Single-Cell Transcriptomic Analysis of Peripheral Blood Reveals Immunological Signatures in Progressive and Stable Idiopathic Pulmonary Fibrosis
This single-cell RNA-seq analysis of peripheral blood from Idiopathic Pulmonary Fibrosis (IPF) patients and controls reveals significant immune dysregulation, particularly in progressive disease. Key findings include increased circulating monocytes, a distinct activated monocyte phenotype, and heightened proliferative activity in CD4+ T cells, alongside a shift towards pro-fibrotic Th2 immune responses. Extensive cell-cell communication alterations and perturbed metabolic pathways underscore a systemic inflammatory and fibrotic environment in IPF progression.
Contents
- Dataset overview
- UMAP Analysis of Single-Cell RNA-seq Data in IPF Conditions
- Validation of `celltype_minor` Annotations using Canonical Marker Gene Expression on UMAP
- Monocyte Condition-Specific Marker Analysis in Idiopathic Pulmonary Fibrosis
- Analysis of Minor Cell Type Populations in IPF Conditions
- T Cell Subset Population Analysis Across IPF Conditions
- Monocyte Population Confirmation Across Conditions
- Differential Abundance of T Cell and Innate Lymphoid Cell Subsets in IPF Conditions
- Monocyte Population Dynamics in Idiopathic Pulmonary Fibrosis Conditions
- Cell-Cell Interaction Analysis in Progressive Idiopathic Pulmonary Fibrosis (IPF)
- Immune Checkpoint Interactions Across IPF Conditions
- Condition-specific Cell-Cell Interaction Patterns in Idiopathic Pulmonary Fibrosis (IPF)
- Monocyte Condition-Specific Surfaceome Markers in IPF
- CD4+ T Cell Surfaceome Marker Analysis Across IPF Conditions
- Cell Cycle Pathway Gene Expression Differences in CD4+ T cells Across IPF Conditions
- Gene Set Enrichment Analysis Reveals Condition-Specific Pathway Alterations Across Immune Cell Types in Idiopathic Pulmonary Fibrosis
- Discussion
- Query List
0. Dataset overview
Dataset Summary
- 데이터 규모: 총 89,619개의 세포와 21,249개의 유전자로 구성된 단일 세포 RNA-seq 데이터입니다.
- 종 및 조직: 사람(human)의 혈액(Blood) 조직에서 유래한 데이터입니다.
- 조건: 'progressive_ipf', 'stable_ipf', 'control' 세 가지 조건으로 구성되어 있습니다.
- 세포 타입: 주요 세포 타입(celltype_major)으로는 T cell, Myeloid cell, Granulocyte 등이 있으며, 세부 세포 타입(celltype_minor, celltype_subset)까지 상세하게 분류되어 있습니다.
- 사전 계산된 결과: 다음 분석 결과들이 미리 계산되어 저장되어 있습니다.
- CCI (Cell-Cell Interaction): 조건별 및 샘플별 세포-세포 상호작용 결과.
- DEG (Differential Expression Genes): 각 celltype_minor에서 특정 조건과 나머지 조건들을 비교한 차등 발현 유전자 결과.
- GSEA (Gene Set Enrichment Analysis): 각 celltype_minor에서 조건별 유전자 세트 농축 분석 결과.
- GSA_up (Gene Ontology): 각 celltype_minor에서 조건별 GO(Gene Ontology) 분석 결과.
1. UMAP Analysis of Single-Cell RNA-seq Data in IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis presents UMAP visualizations of single-cell RNA-seq data, displaying the distribution of 89,619 cells across 21,249 genes, annotated by various metadata fields: condition, sample, major cell type, minor cell type, and cell type subset. The data originates from human blood samples across 'control', 'progressive_ipf', and 'stable_ipf' conditions, providing an initial overview of the dataset structure and the quality of cell type annotations and batch effect integration.
Visual Summary
Condition Overlay
The UMAP plot colored by 'condition' shows a notable degree of mixing among 'control', 'progressive_ipf', and 'stable_ipf' cells across many clusters. However, there are also regions where specific conditions appear to be enriched. For instance, 'progressive_ipf' (yellow) cells show some distinct clusters, particularly in smaller, less dense regions, and also contribute to the larger, more mixed clusters. 'Stable_ipf' (blue) and 'control' (maroon) cells are generally well-interspersed throughout the main cellular populations, suggesting common cell types are present across conditions, but with potential condition-specific shifts in cellular states or proportions in certain areas. This mixed distribution indicates that the primary drivers of the UMAP structure are likely cell type identity rather than condition alone, though condition-specific perturbations are also visible.
Sample Overlay
The 'sample' UMAP reveals that cells from individual samples (e.g., C27-C40, P01-P12, S14-S26) are largely integrated across the UMAP space. There are no overtly dominant sample-specific clusters that would suggest strong batch effects, which is a positive indication of successful data integration. While some samples might show slightly denser representation within certain cell type clusters (as expected due to biological variability in cell composition), the overall intermixing of colors suggests that most cellular populations contain contributions from multiple samples. This pattern supports the notion that the observed UMAP structure reflects biological distinctions rather than technical artifacts.
Cell Type Major Overlay
The 'celltype_major' UMAP clearly demonstrates that major cell types form distinct, well-separated clusters. T cells (cyan/green shades) form a large, complex cluster, while Myeloid cells (light orange) occupy another distinct region. B cells (maroon) and Granulocytes (dark orange) form smaller, but well-defined clusters. Platelets (light green) are also identifiable. This strong separation indicates robust identification and clustering of major immune cell lineages in the blood. The 'unassigned' cells (dark purple) appear sparsely distributed across several regions, suggesting they might represent rare cell types or cells with ambiguous transcriptional profiles.
Cell Type Minor Overlay
Refining the view from 'celltype_major', the 'celltype_minor' UMAP further confirms excellent cell type separation. Within the broader T cell cluster, 'T cell CD4+' (light blue) and 'T cell CD8+' (dark blue) populations are clearly delineated. Monocytes (light orange) are well-separated, and Neutrophils (light yellow) form a distinct cluster. NK cells (dark yellow), ILCs (orange), B cells (maroon), Platelets (light green), and Eosinophils (red) also show strong clustering. This fine-grained resolution into minor cell types further validates the quality of the cell annotation and the underlying transcriptional data. The 'unassigned' cells remain scattered, as noted previously.
Cell Type Subset Overlay
The 'celltype_subset' UMAP provides the highest resolution of cell identity, showing remarkable sub-clustering within major and minor cell types. For example, within T cells, distinct populations such as 'T cell (Naive)' (light green), 'T cell (Cytotoxic)' (green), 'T cell (Treg)' (dark blue), and various Th subsets (Th1, Th2, Th9, Th17, Th22, Tfh - various shades of blue/green) are visible as separated or interconnected sub-clusters. Similarly, B cell subsets like 'B cell (Memory)' (maroon), BMZ (dark red), Bf (red), and Breg (orange-red) are discernible. Monocytes (light yellow), NK cells (dark yellow), Neutrophils (light yellow), Platelets (light green), and Eosinophils (red) also maintain their distinct clustering. This granular separation at the subset level indicates highly accurate and informative cell type annotation, enabling detailed analyses of specific immune cell populations.
Biological Interpretation
The UMAP visualizations collectively paint a clear picture of the cellular landscape in the human blood samples, with a focus on immune cells relevant to IPF.
- Robust Cell Type Identification: The excellent segregation of major, minor, and subset cell types strongly supports the quality of the single-cell RNA-seq data and the accuracy of the cell type annotations. This foundation is crucial for any subsequent differential expression, cell-cell interaction, or pathway analysis, as it ensures that comparisons are made between genuinely distinct cell populations.
- Batch Effect Management: The intermixing of cells from different samples (C, P, S prefixes) across the UMAP suggests that any potential batch effects have been largely mitigated during data integration, allowing for more reliable biological comparisons across individuals and conditions.
- Condition-Specific Patterns: While cell types are the primary drivers of the global UMAP structure, the subtle but discernible enrichment of 'progressive_ipf' cells in certain areas indicates that this condition may involve unique transcriptional states or altered proportions of specific cell populations. The presence of 'control' and 'stable_ipf' cells often mixed with each other and also with 'progressive_ipf' cells in the main clusters suggests that many core immune functions might be shared, but disease progression in IPF (progressive_ipf) likely involves specific shifts in cell states or composition.
- Implications for IPF Research: The detailed cell type subset annotations, especially within T cells (e.g., various Th subsets, Treg, Cytotoxic T cells) and B cells (memory, regulatory B cells), are highly valuable for understanding the complex immune dysregulation in IPF. For instance, specific Th cell subsets are known to play distinct roles in fibrosis and inflammation. The ability to resolve these at a granular level in blood provides a systemic view of immune changes. PubMed search: T cell subsets in idiopathic pulmonary fibrosis
Annotation Notes
The cell type annotations, across major, minor, and subset levels, demonstrate high quality and consistency with the underlying transcriptional profiles. The clusters on the UMAP are well-defined and correspond effectively to the assigned cell identities. The presence of a small number of 'unassigned' cells is typical in single-cell datasets and does not detract from the overall annotation quality, as the vast majority of cells are robustly classified. This robust annotation provides a strong basis for downstream analyses.
2. Validation of `celltype_minor` Annotations using Canonical Marker Gene Expression on UMAP
[Analysis Visualization Results]...
Analysis Overview
This analysis visualizes the expression of a panel of canonical marker genes for various immune cell types on a Uniform Manifold Approximation and Projection (UMAP) plot. Concurrently, a UMAP plot colored by celltype_minor annotation is provided. The primary objective is to assess and validate the quality of the celltype_minor cell type assignments by comparing known gene expression patterns with the annotated clusters.
Visual Summary
The UMAP projections clearly delineate distinct clusters corresponding to different immune cell populations identified by the celltype_minor annotation.
- celltype_minor UMAP: This plot displays well-separated clusters for major blood cell types, including distinct regions for T cell CD4+, T cell CD8+, Monocytes, Neutrophils, B cells, NK cells, ILCs, Platelets, and Eosinophils. An 'unassigned' population is also present, indicating cells that could not be confidently classified into specific minor types.
The expression patterns of the selected marker genes align remarkably well with these annotated clusters:
- CD3D: As a pan T-cell marker, CD3D shows high expression across the entire T cell compartment, encompassing both T cell CD4+ and T cell CD8+ clusters. [GeneCards]
- CD4: Expression is highly enriched in the cluster annotated as "T cell CD4+", demonstrating specificity for this T cell subset. [GeneCards]
- CD8A: Similarly, CD8A expression is predominantly localized to the "T cell CD8+" cluster, confirming its role as a specific marker for cytotoxic T cells. [GeneCards]
- CD79A: This gene, a known B cell marker, shows strong and specific expression within the cluster annotated as "B cell". [GeneCards]
- CD14: Expression of CD14, a canonical marker for monocytes, is highly concentrated in the "Monocyte" cluster. [GeneCards]
- LYZ: Lysozyme (LYZ) shows robust expression across the myeloid compartment, particularly within the "Monocyte" and "Neutrophil" clusters, consistent with its function in these phagocytic cells. [GeneCards]
- NKG7: Natural Killer Cell Granule Protein 7 (NKG7), a marker for cytotoxic lymphocytes, exhibits high expression in the "NK cell" cluster and also in a subset of "T cell CD8+" cells, reflecting its presence in both NK cells and cytotoxic T lymphocytes. [GeneCards]
- S100A9: This gene, associated with myeloid inflammation and granulocytes, shows elevated expression in the "Neutrophil" cluster and also in the "Monocyte" population, consistent with its known expression patterns. [GeneCards]
- ITGA2B: Integrin Subunit Alpha 2b (ITGA2B), a crucial component of the platelet-specific glycoprotein IIb/IIIa complex, is highly expressed in a distinct, compact cluster identified as "Platelet". [GeneCards]
Biological Interpretation
The strong concordance between the expression patterns of these canonical marker genes and the celltype_minor annotations provides robust biological validation for the cell type assignments. Each gene exhibits preferential expression within its expected cell population, clearly delineating these cell types in the UMAP space. This indicates that the clustering and annotation processes have successfully captured the unique transcriptional signatures of the different minor blood cell populations. For example, the precise segregation of CD4 and CD8A expression to their respective T cell subsets highlights the granularity and accuracy of the T cell annotations. Similarly, the specific expression of CD79A for B cells, CD14 and LYZ for myeloid cells (monocytes and neutrophils), NKG7 for cytotoxic lymphocytes, S100A9 for granulocytes/myeloid cells, and ITGA2B for platelets collectively confirms the biological identity of these populations within the human blood tissue.
Annotation Notes
The visualization of marker gene expression on the UMAP along with the celltype_minor annotation confirms a high quality of cell type assignment. The distinct and localized expression of each marker gene within its expected cell cluster strongly supports the accuracy and biological validity of the celltype_minor annotations. This foundational validation step is critical for ensuring confidence in downstream analyses, such as differential gene expression or cell-cell interaction studies, which rely on correctly identified cell populations. The presence of an "unassigned" cluster indicates that some cells could not be confidently classified, which is a common and appropriate outcome in single-cell analysis, highlighting areas for potential further investigation if deeper classification of these cells is required.
3. Monocyte Condition-Specific Marker Analysis in Idiopathic Pulmonary Fibrosis
[Analysis Visualization Results]...
Analysis Overview
This analysis identifies and visualizes condition-specific gene expression markers within the Monocyte cell type, comparing control individuals with those diagnosed with stable Idiopathic Pulmonary Fibrosis (IPF). The dot plot displays the mean expression level and the fraction of cells expressing specific genes across individual samples, grouped by condition. This helps to uncover distinct molecular phenotypes of monocytes that may differentiate healthy individuals from those with stable IPF.
Visual Summary
The dot plot effectively illustrates the differential expression patterns of selected marker genes in monocytes across control and stable IPF samples.
- Distinct Gene Clusters by Condition: The samples are clearly separated into 'control' and 'stable_ipf' groups, reflecting significant transcriptional differences in their monocyte populations.
- Control-Specific Markers: Genes such as HBEGF, HCAR3, and AREG show consistently higher mean expression (darker red dots) and are expressed in a larger fraction of cells (larger dot size) primarily within the control samples (e.g., C27, C32, C31, C34). The first red box highlights this cluster of genes and their preferential expression in controls.
- Stable IPF-Specific Markers: In stark contrast, genes like HLA-DQA2, AQP9, HLA-G, FPR2, FFAR2, and STEAP4 exhibit elevated mean expression and higher cell fraction positivity predominantly in stable IPF samples (e.g., P06, P01, S20, S17, S26, S25). The second red box clearly delineates this set of genes, indicating their association with the stable IPF condition.
- Sample Representation: The bar chart on the right indicates the total number of monocytes contributing to each sample, ranging from approximately 200 to over 1300 cells, confirming sufficient cell numbers for robust analysis across samples.
Biological Interpretation
The observed shift in monocyte gene expression profiles between control and stable IPF conditions suggests a significant phenotypic reprogramming of these immune cells in the context of the disease.
- Control Monocyte Signatures: The higher expression of HBEGF, HCAR3, and AREG in control monocytes may reflect a homeostatic or resting state, potentially involved in basal tissue maintenance or anti-inflammatory regulation.
- HBEGF (Heparin-binding EGF-like growth factor) is involved in cell proliferation and tissue repair, often mediating homeostatic functions. GeneCards: HBEGF
- HCAR3 (Hydroxycarboxylic acid receptor 3) is a G protein-coupled receptor linked to anti-inflammatory pathways. GeneCards: HCAR3
- AREG (Amphiregulin) plays roles in epithelial proliferation and inflammation, often in tissue repair contexts. GeneCards: AREG
- Stable IPF Monocyte Signatures: The marked upregulation of HLA-DQA2, AQP9, HLA-G, FPR2, FFAR2, and STEAP4 in stable IPF monocytes points towards an activated and transcriptionally altered state, likely contributing to the chronic inflammation and fibrosis characteristic of IPF.
- HLA-DQA2 and HLA-G are Major Histocompatibility Complex (MHC) molecules. Upregulation of HLA-DQA2 (MHC class II) suggests enhanced antigen presentation capabilities, which can drive T cell responses and perpetuate chronic inflammation in IPF. HLA-G (non-classical MHC class I) is often associated with immune tolerance but can also be dysregulated in disease to evade immune surveillance or modulate the inflammatory environment. GeneCards: HLA-DQA2, GeneCards: HLA-G
- FPR2 (Formyl peptide receptor 2) is a key receptor involved in sensing both pro-inflammatory and pro-resolving mediators, indicating active involvement of these monocytes in the inflammatory milieu of IPF. GeneCards: FPR2
- FFAR2 (Free fatty acid receptor 2) responds to short-chain fatty acids, linking metabolic changes or gut microbiome activity to immune cell function. Its upregulation suggests altered metabolic sensing by monocytes in IPF. GeneCards: FFAR2
- AQP9 (Aquaporin 9) is involved in water and glycerol transport, potentially impacting monocyte migration and metabolic activity in fibrotic tissues. GeneCards: AQP9
- STEAP4 (STEAP family member 4) is a metalloreductase implicated in lipid metabolism and inflammation, suggesting metabolic reprogramming of monocytes in the disease context. GeneCards: STEAP4
These findings highlight a distinct "IPF-associated monocyte" phenotype characterized by altered immune activation, metabolic sensing, and inflammatory pathway engagement, which likely contributes to the pathogenesis of pulmonary fibrosis.
Clinical or Translational Implications
The identification of these condition-specific monocyte markers offers several avenues for clinical and translational impact in IPF:
- Biomarker Discovery: The genes highly expressed in stable IPF monocytes (e.g., HLA-DQA2, FPR2, FFAR2) represent strong candidates for blood-based diagnostic or prognostic biomarkers. These could help identify patients with stable IPF, monitor disease progression, or predict treatment response.
- Therapeutic Targets: Receptors like FPR2 and FFAR2 are druggable targets. Modulating their activity via specific agonists or antagonists could offer novel therapeutic strategies to reprogram monocyte function, potentially dampening pro-fibrotic responses or promoting resolution of inflammation in IPF.
- Disease Mechanisms: Further investigation into the functional consequences of upregulating genes like HLA-DQA2 and HLA-G could elucidate critical immune mechanisms driving IPF progression, such as aberrant antigen presentation or immune evasion strategies employed by the lung microenvironment.
- Experimental Validation: These identified markers can be validated at the protein level using techniques such as flow cytometry or mass cytometry (CyTOF) on patient blood or bronchoalveolar lavage (BAL) samples to confirm their utility as surface markers for specific monocyte subsets in IPF patients. This could enable the precise identification and isolation of disease-relevant monocyte populations for further functional studies.
4. Analysis of Minor Cell Type Populations in IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis presents a population bar plot illustrating the relative proportions of minor cell types across individual samples, grouped by disease condition: 'control', 'progressive_ipf', and 'stable_ipf'. The data originates from single-cell RNA sequencing of blood samples, and cell types are categorized at the 'minor' taxonomic level. This visualization helps to understand the systemic immune cell landscape in Idiopathic Pulmonary Fibrosis (IPF) patients compared to controls, and to identify potential differences between stable and progressive forms of the disease.
Visual Summary
The stacked bar plot visualizes the percentage contribution of each minor cell type to the total cell population within each blood sample.
- Dominant Cell Types: Monocytes (orange), T cell CD4+ (light green), and T cell CD8+ (teal) consistently represent the largest proportions across all samples and conditions.
- Monocyte Proportions: Monocytes appear to show a trend of increased relative abundance in some 'progressive_ipf' samples (e.g., P02, P05, P08, P07) compared to 'control' samples. In 'progressive_ipf', monocytes can constitute up to 50-60% of the blood cells in some individuals. While still substantial, their proportion in 'control' and 'stable_ipf' appears slightly lower on average.
- B Cell Proportions: B cells (dark red) are generally present in low proportions (<10%) in 'control' samples. However, their relative proportion appears noticeably increased in several 'progressive_ipf' samples (e.g., P02, P05, P08, P09, P11, P03) and 'stable_ipf' samples (e.g., S20, S81, S15, S26, S24), sometimes reaching up to 10-20% of the total cells. There is higher sample-to-sample variability in B cell proportions within the IPF groups compared to controls.
- T Cell Proportions (CD4+ and CD8+): T cell populations remain significant across all conditions. In samples where monocytes and/or B cells show a marked increase, the *relative* proportions of T cells (CD4+ and CD8+) appear correspondingly reduced, although their absolute numbers cannot be inferred from this relative plot.
- Other Minor Cell Types: NK cells (yellow), Neutrophils (light yellow), Platelets (light green), Eosinophils (red), and ILCs (red-orange) constitute relatively smaller fractions of the total population, often appearing as thin bands or being absent in many samples. Neutrophils show some variability, being more apparent in certain samples within the IPF groups.
- Unassigned Cells: The proportion of 'unassigned' cells (dark blue) is consistently very low across all samples, indicating high confidence in the cell type annotations.
Biological Interpretation
The observed shifts in peripheral blood cell populations provide insights into the systemic immune response in IPF, particularly distinguishing between control, stable, and progressive disease states.
- Monocyte Expansion in Progressive IPF: The trend of increased relative monocyte proportions in progressive IPF patients suggests an activated systemic inflammatory state. Monocytes are critical precursors to macrophages, which are known to play a central role in the pathogenesis of IPF, contributing to chronic inflammation, tissue remodeling, and fibrosis [1]. An elevated circulating monocyte pool could indicate increased recruitment of these cells to the fibrotic lung, driving disease progression.
- B Cell Involvement in IPF: The noticeable increase in B cell proportions in both progressive and stable IPF, especially compared to controls, highlights the potential involvement of humoral immunity in IPF. B cells can contribute to inflammation, autoantibody production, and organization of tertiary lymphoid structures in fibrotic lungs, all of which are implicated in IPF pathogenesis [2]. The variability within IPF samples could reflect the heterogeneity of immune responses among patients.
- Immune Landscape Shift: The relative reduction in T cell proportions when monocytes and B cells are elevated suggests a potential shift in the overall immune cell landscape in IPF patients, favoring cell types more directly involved in inflammation and fibrosis. This alteration could disrupt the finely tuned balance of immune regulation and exacerbate the disease.
Clinical or Translational Implications
The findings from this peripheral blood cell population analysis have several potential clinical and translational implications:
- Biomarkers for Disease Progression: Changes in the relative proportions of monocytes and B cells in peripheral blood could serve as accessible and quantifiable biomarkers for IPF activity or progression. Monitoring these changes over time might help in identifying patients at higher risk of progressive disease.
- Therapeutic Targets: If an expanded monocyte or B cell population contributes to disease pathogenesis, targeting these cell types or their activating pathways could represent novel therapeutic strategies for IPF. This could involve immunomodulatory drugs that suppress monocyte activation or B cell function.
- Patient Stratification and Monitoring: Understanding these shifts in peripheral blood populations could aid in stratifying IPF patients for specific therapies or in monitoring treatment response. For instance, a patient with persistently high monocyte or B cell proportions might benefit from more intensive anti-inflammatory or immunomodulatory treatment regimens.
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References:
- Monocytes/Macrophages in IPF:
PubMed Search: Idiopathic Pulmonary Fibrosis Macrophage Monocyte
- B Cells in IPF:
PubMed Search: Idiopathic Pulmonary Fibrosis B cell
5. T Cell Subset Population Analysis Across IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
이 분석은 단일 세포 RNA 시퀀싱(scRNA-seq) 데이터를 활용하여 대조군(control), 진행성 특발성 폐섬유증(progressive_ipf), 안정성 특발성 폐섬유증(stable_ipf) 환자 간의 혈액 내 T 세포 및 관련 림프구 아형(ILC, NK cell)의 상대적 분포를 비교합니다. plot_celltype_population 도구를 사용하여 각 샘플에 대한 T 세포 아형 구성 비율을 시각화하였습니다. 이 결과는 특발성 폐섬유증(IPF)의 진행과 안정성 상태에서 면역 세포 구성에 변화가 있는지 탐색하는 데 도움을 줍니다.
Visual Summary
제공된 스택형 막대 그래프는 각 조건(control, progressive_ipf, stable_ipf)별 개별 샘플에서 T 세포 주요 그룹 내의 다양한 아형(T cell (Naive), T cell (Cytotoxic), T cell (Treg) 등, 그리고 ILC 및 NK 세포)의 상대적 비율을 보여줍니다.
- 주요 아형의 지배력: 모든 샘플 및 조건에서 T cell (Naive)과 T cell (Cytotoxic)이 전체 T 세포 집단의 상당 부분을 차지하며 가장 우세한 아형으로 나타납니다.
- Naive T 세포의 변화 가능성: Naive T 세포(옅은 노란색)의 비율은 대조군 샘플에서 상대적으로 높은 경향을 보입니다. 반면, 진행성 및 안정성 IPF 샘플에서는 Naive T 세포의 비율이 대조군에 비해 다소 감소하거나 샘플 간 변동성이 더 커 보이는 경향이 관찰됩니다. 이는 Naive T 세포의 풀(pool) 감소 또는 다른 아형으로의 분화 증가를 시사할 수 있습니다.
- Cytotoxic T 세포의 변화 가능성: Naive T 세포의 변화와 연관되어, T cell (Cytotoxic)(옅은 주황색)의 비율은 IPF 환자군에서 일부 샘플에서 대조군 대비 상대적으로 증가하는 경향을 보입니다.
- 조절 T 세포 (Treg) 및 다른 Th 아형: T cell (Treg)(짙은 파란색)은 모든 조건에서 일관되게 소량의 비율을 차지하며, 시각적으로 명확한 조건 간 차이는 뚜렷하지 않습니다. Th1, Th2, Th9, Th17, Th22, Tfh를 포함한 다른 T helper (Th) 세포 아형들은 전반적으로 매우 낮은 비율을 보이며, 조건 간의 뚜렷한 변화는 시각적으로 구별하기 어렵습니다. 특히 Th2 세포는 거의 감지되지 않을 정도로 매우 낮은 비율을 차지합니다.
- NK 세포 및 ILCs: NK 세포(옅은 주황색)는 T 세포만큼은 아니지만 일정 비율을 차지하며, 샘플 간 변동성이 큽니다. ILC1, ILC2, ILC3 (NCR+), ILC3 (NCR-), ILCreg, LTI 등 Innate Lymphoid Cells (ILCs)(짙은 빨간색/주황색 계열) 아형들은 모든 조건에서 매우 적은 비율을 보이며, 전반적으로 T 세포 집단 내에서 미미한 부분을 구성합니다.
Biological Interpretation
이 혈액 T 세포 및 관련 림프구 아형의 구성 분석은 IPF 환자에서 면역 반응의 변화를 시사합니다.
- 면역 활성화 및 Naive T 세포 감소: IPF 환자(진행성 및 안정성 모두)에서 Naive T 세포의 상대적 감소 경향은 만성적인 면역 활성화 또는 T 세포가 염증 및 섬유화 과정에 참여하기 위해 활성화되고 분화됨을 나타낼 수 있습니다. Naive T 세포는 항원에 노출되지 않은 세포로, 이들의 감소는 면역계의 지속적인 자극을 반영할 수 있습니다.
- 세포독성 T 세포의 역할: T cell (Cytotoxic)의 상대적 증가 가능성은 IPF에서 조직 손상 및 재형성 과정에 기여하는 세포독성 면역 반응이 활성화될 수 있음을 시사합니다. Cytotoxic T 세포는 바이러스 감염이나 자가면역 질환에서 세포 사멸을 유도하는 역할을 합니다.
- 조절 T 세포의 상대적 안정성: 혈액 내 T cell (Treg) 비율이 조건 간에 크게 변하지 않는다는 점은 전신 순환계에서는 Treg 풀의 큰 변화가 없거나, Treg 기능의 변화가 수적 변화보다 더 중요할 수 있음을 의미합니다. IPF 폐 조직 내에서의 Treg 분포 및 기능은 혈액과 다를 수 있으므로 추가적인 조사가 필요합니다.
- 미미한 Th2 세포 비율: IPF는 종종 Th2 면역 반응과 관련된 섬유화 경로(예: IL-4, IL-13)와 연관된다고 알려져 있습니다. 그러나 본 혈액 샘플 분석에서는 Th2 세포의 비율이 매우 낮게 나타납니다. 이는 IPF에서 Th2 세포의 역할이 주로 폐 조직 내에서 국소적으로 나타나거나, 혈액 내에서는 그 수가 적더라도 활성화 상태가 변화하는 방식으로 기여할 수 있음을 시사합니다.
- ILCs 및 NK 세포의 제한된 변화: ILCs 및 NK 세포는 면역 반응의 초기 단계에서 중요한 역할을 하지만, 이 분석에서는 T 세포 풀 내에서 그 비율이 매우 낮고 조건 간 뚜렷한 차이가 관찰되지 않았습니다. 이는 이들 세포 아형의 수가 전신 순환에서 크게 변하지 않거나, 이들 세포의 기능적 변화가 수적 변화보다 더 중요할 수 있음을 의미합니다.
Clinical or Translational Implications
이러한 T 세포 아형 구성의 변화는 IPF의 병태생리학적 이해를 심화하는 데 기여할 수 있습니다.
- 질병 진행 바이오마커로서의 잠재력: 혈액 내 Naive T 세포의 비율 변화는 IPF의 진행 또는 질병 활성도를 나타내는 잠재적 바이오마커로 고려될 수 있습니다. T 세포 아형의 불균형은 질병의 면역병리학적 특징을 반영할 수 있습니다.
- 면역 조절 치료 표적: IPF에서 관찰되는 T 세포 아형의 변화는 특정 T 세포 아형을 표적으로 하는 면역 조절 치료 전략 개발의 근거를 제공할 수 있습니다. 예를 들어, 병적으로 증가한 세포독성 T 세포 활성을 억제하거나, 불충분한 Treg 기능을 강화하는 접근 방식 등이 고려될 수 있습니다.
- 조직 특이적 분석의 필요성: 혈액 내 면역 세포 조성은 전신 면역 상태를 반영하지만, 폐 섬유화의 핵심 부위인 폐 조직 내 면역 환경과는 다를 수 있습니다. 따라서 이러한 혈액 기반 분석 결과는 폐 조직 내 면역 세포 구성 및 활성에 대한 추가 연구의 필요성을 강조합니다.
참고 문헌:
- Idiopathic Pulmonary Fibrosis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8900088/
- T cells in Pulmonary Fibrosis: https://pubmed.ncbi.nlm.nih.gov/30678250/
6. Monocyte Population Confirmation Across Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis utilizes the plot_celltype_population tool to visualize the population of Monocytes (from celltype_minor annotation) across different samples and experimental conditions (control, progressive_ipf, stable_ipf). The primary goal appears to be a confirmation of the presence and consistent annotation of Monocyte cells within the dataset, specifically for cells designated as Monocytes.
Visual Summary
The visualization consists of three bar plots, one for each condition: 'control', 'progressive_ipf', and 'stable_ipf'. Each subplot displays multiple bars, with each bar representing an individual sample within that condition. All bars across all samples and conditions are uniformly colored in maroon, labeled 'Monocyte' in the legend, and extend to 100% on the y-axis.
Biological Interpretation
The plot indicates that for every sample displayed under the 'control', 'progressive_ipf', and 'stable_ipf' conditions, the population being visualized consists entirely of Monocytes (100%). Given the parameters used (targets: {'obs_col': 'celltype_minor', 'value': 'Monocyte'}), this plot serves primarily as a confirmation that the data subset being analyzed or visualized for each sample is indeed composed exclusively of cells classified as Monocytes.
This visualization confirms the following:
- Consistent Monocyte Annotation: Monocyte cells are consistently identified and present across all individual samples included in the dataset, spanning both healthy controls and different stages of Idiopathic Pulmonary Fibrosis (IPF) (progressive and stable).
- Data Filtering Validation: The plot implicitly validates the selection process for Monocyte cells, confirming that when filtering for celltype_minor == 'Monocyte', all selected cells are indeed annotated as such.
It is important to note that this plot does not depict the relative abundance or proportion of Monocytes compared to other cell types (e.g., T cells, B cells, Neutrophils) within the total peripheral blood mononuclear cell (PBMC) population of each sample. To understand the *change in the overall frequency* of Monocytes in the context of IPF, a different type of population plot showing the percentage of Monocytes relative to all cell types would be required. This current plot specifically confirms that the Monocyte population *itself* is consistently identified within the context of the requested visualization.
Clinical or Translational Implications
While this specific plot does not provide direct insights into differential Monocyte abundance in IPF, it is a crucial prerequisite for subsequent cell-type-specific analyses. Confirming the consistent identification and presence of Monocytes across all conditions (control, progressive_ipf, stable_ipf) ensures that any downstream differential gene expression (DEG), cell-cell interaction (CCI), or pathway enrichment (GSEA/GSA) analyses performed on Monocytes are based on a reliably defined cell population. Monocytes are known to play a significant role in inflammatory and fibrotic diseases like IPF, differentiating into macrophages that contribute to disease progression [1]. Therefore, their consistent identification is foundational for investigating their specific roles and potential as therapeutic targets or biomarkers in IPF.
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References
- Monocytes and Macrophages in Idiopathic Pulmonary Fibrosis: A PubMed search query: https://pubmed.ncbi.nlm.nih.gov/?term=monocytes+macrophages+idiopathic+pulmonary+fibrosis
7. Differential Abundance of T Cell and Innate Lymphoid Cell Subsets in IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates the proportional differences of various T cell and innate lymphoid cell (ILC) subsets in peripheral blood across control individuals, patients with stable Idiopathic Pulmonary Fibrosis (IPF), and patients with progressive IPF. The box plots visually represent the celltype proportions, and statistical significance (p < 0.1, with an absolute log2 fold change > 0.1) is annotated for comparisons between conditions. This helps identify immune cell population shifts associated with different IPF disease states.
Visual Summary
The visualization displays box plots for eight immune cell subsets: Th22, unassigned, NK cell, ILC3(-), Th17, ILC2, Th2, and ILC1. Each plot compares the celltype proportion across three conditions: stable_ipf, control, and progressive_ipf.
Key observations from the plots are:
- Th22 Cells: Show a significantly higher proportion in progressive_ipf patients compared to both control (p=0.05) and stable_ipf (p=0.08) groups.
- Th17 Cells: Exhibited significantly lower proportions in both stable_ipf (p≤0.01) and progressive_ipf (p≤0.05) groups when compared to control individuals.
- Th2 Cells: The proportion is significantly lower in stable_ipf compared to control (p≤0.05). Notably, progressive_ipf shows a significantly higher proportion of Th2 cells compared to stable_ipf (p≤0.05).
- NK Cells: Are found in significantly higher proportions in stable_ipf patients compared to control individuals (p≤0.05).
- "unassigned" Cells: This category is significantly more abundant in control samples compared to both stable_ipf (p=0.07) and progressive_ipf (p≤0.05).
- ILC1, ILC2, and ILC3(-): No statistically significant differences in proportions were observed for these innate lymphoid cell subsets across the tested conditions (p ≥ 0.08).
Biological Interpretation
The observed shifts in immune cell proportions in peripheral blood highlight potential immunological imbalances associated with IPF progression.
- Pro-fibrotic/Pro-inflammatory Shifts in Progressive IPF:
- Increased Th22 cells in progressive IPF: Th22 cells produce IL-22, which has complex roles in tissue inflammation and repair. An elevation in Th22 cells in progressive IPF suggests a heightened inflammatory or tissue remodeling state that may contribute to disease worsening. In fibrotic conditions, IL-22 can both promote epithelial integrity and contribute to inflammatory responses depending on the context [1].
- Increased Th2 cells in progressive IPF (vs. stable IPF): Th2 cells are crucial in allergic inflammation and are well-established contributors to fibrosis in various organs, including the lung. Their signature cytokines (IL-4, IL-5, IL-13) promote fibroblast activation, collagen production, and extracellular matrix deposition [2]. The observed increase in Th2 cell proportion from stable to progressive IPF suggests a shift towards a more profibrotic immune environment with disease progression.
- Immune Alterations in Stable IPF:
- Reduced Th17 cells in IPF (both stable and progressive) compared to controls: Th17 cells, characterized by IL-17 production, are pro-inflammatory and involved in autoimmune diseases. A reduction in blood Th17 cells in IPF patients might indicate their sequestration to inflamed lung tissue, altered differentiation, or a systemic downregulation in peripheral circulation compared to healthy individuals [3].
- Reduced Th2 cells in stable IPF (vs. control): The lower proportion of Th2 cells in stable IPF compared to controls, followed by an increase in progressive IPF, suggests a dynamic change in Th2 responses throughout the disease course. Stable disease might have mechanisms that suppress peripheral Th2 responses, which are then overwhelmed as the disease progresses.
- Increased NK cells in stable IPF (vs. control): Natural Killer (NK) cells are cytotoxic lymphocytes that play a role in innate immunity and immune surveillance. Their higher proportion in stable IPF could reflect a compensatory immune activation or a specific immunoregulatory mechanism that contributes to disease stability. NK cells are known to influence fibrotic processes, with some studies suggesting a protective role [4].
- "unassigned" Cell Population: The higher proportion of "unassigned" cells in controls and their reduction in IPF conditions could imply that certain cell states or populations found in healthy individuals are either undergoing differentiation, being consumed, or are no longer distinguishable by the current annotation scheme in the context of IPF. Further investigation into the markers of these "unassigned" cells would be necessary for a meaningful interpretation.
Clinical or Translational Implications
These findings highlight distinct peripheral immune signatures that differentiate stable IPF from progressive IPF, and both from healthy controls.
- Biomarker Potential: The proportions of Th22 and Th2 cells, in particular, could serve as potential peripheral blood biomarkers to monitor IPF disease progression or to stratify patients at risk of worsening fibrosis.
- Therapeutic Targets: The observed changes in Th22, Th17, Th2, and NK cell populations suggest that modulating the activity or proportion of these specific cell types could be relevant for therapeutic interventions in IPF. For instance, therapies targeting Th2-mediated profibrotic pathways might be particularly beneficial for patients with progressive disease.
References
[1] For a general understanding of IL-22 and Th22 cells in disease:
PubMed search: Th22 cells IL-22 lung disease fibrosis
[2] For Th2 cells and fibrosis:
PubMed search: Th2 cells fibrosis lung IPF
[3] For Th17 cells in IPF:
PubMed search: Th17 cells idiopathic pulmonary fibrosis blood
[4] For NK cells in fibrotic diseases:
PubMed search: NK cells fibrosis lung
8. Monocyte Population Dynamics in Idiopathic Pulmonary Fibrosis Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates the proportion of Monocyte cells in the peripheral blood across different conditions: control, stable idiopathic pulmonary fibrosis (IPF), and progressive IPF. The celltype proportions were derived from single-cell RNA sequencing data. Box plots are used to visualize the distribution of Monocyte proportions for each condition, with individual sample data points overlaid. Statistical significance tests highlight differences between specific condition pairs.
Visual Summary
The box plot illustrates distinct patterns in Monocyte celltype proportion across the three conditions:
- Control: The median Monocyte proportion is the lowest among the groups, approximately 27%.
- Stable IPF: The median Monocyte proportion is slightly elevated compared to the control group, around 31%. The difference between control and stable_ipf did not reach statistical significance (p = 0.21).
- Progressive IPF: This group exhibits the highest median Monocyte proportion, approximately 43%.
Statistical Significance
- A highly significant increase in Monocyte proportion is observed in progressive IPF compared to control (p ≤ 0.001).
- A statistically significant increase in Monocyte proportion is also evident in progressive IPF compared to stable IPF (p ≤ 0.01).
Overall, there is a clear trend of increasing Monocyte proportion from control to stable IPF, and a further, statistically significant, increase in progressive IPF. This suggests that a higher proportion of circulating monocytes is associated with the more severe and progressive form of IPF.
Biological Interpretation
Monocytes are key innate immune cells that play crucial roles in inflammation, tissue repair, and fibrosis. In the context of Idiopathic Pulmonary Fibrosis (IPF), dysregulation of immune cells, including monocytes and their differentiated forms (macrophages), is strongly implicated in disease pathogenesis.
The observed increase in circulating Monocyte proportion in progressive IPF patients suggests a heightened systemic inflammatory or pro-fibrotic state. Monocytes are known precursors to macrophages, which can adopt various phenotypes, including pro-inflammatory (M1) and pro-fibrotic (M2) states. In IPF, recruited monocytes differentiate into alveolar macrophages and interstitial macrophages, which contribute to the fibrotic cascade by secreting profibrotic mediators (e.g., TGF-β, PDGF) and driving fibroblast activation and extracellular matrix deposition [1].
The significant difference between stable and progressive IPF highlights that not just the presence of IPF, but the *progression* of the disease, correlates with a more pronounced increase in peripheral Monocytes. This could reflect:
- Increased production: Enhanced myelopoiesis in the bone marrow in response to chronic inflammation or injury signals from the lung.
- Altered trafficking: Changes in monocyte egress from the bone marrow or retention in the circulation due to dysregulated chemokine signaling.
- Disease severity marker: A higher proportion of circulating monocytes might serve as a systemic indicator of the extent of active inflammation and fibrosis occurring in the lung tissue.
Clinical or Translational Implications
The finding that a higher proportion of circulating Monocytes is significantly associated with progressive IPF has several potential clinical implications:
- Biomarker for Progression: Monocyte proportion in peripheral blood could serve as a readily accessible, non-invasive biomarker to help differentiate between stable and progressive forms of IPF, or to monitor disease progression. This could aid in risk stratification and guide treatment decisions for IPF patients.
- Therapeutic Target Indication: Given the established role of monocytes/macrophages in IPF pathogenesis, the increased number of circulating monocytes in progressive disease reinforces the rationale for targeting monocyte recruitment, differentiation, or activation as a potential therapeutic strategy. Modulating the systemic monocyte pool or its pro-fibrotic subsets could potentially slow disease progression [2].
- Understanding Disease Heterogeneity: The distinction between stable and progressive IPF based on Monocyte proportions provides insights into the immunological differences underlying disease heterogeneity. Further investigation into the specific subsets of monocytes (e.g., classical, intermediate, non-classical) that are elevated could offer more refined insights into their specific contributions to IPF progression.
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References
[1] Hutchenreuther, J., et al. (2020). Macrophages in Pulmonary Fibrosis: From Pathogenesis to Therapeutics. *International Journal of Molecular Sciences*, 21(19), 7056. PubMed Search: "Macrophages pulmonary fibrosis pathogenesis"
[2] Genentech. (2022). IPF Disease Pathophysiology. Genentech Pulmonary Pipeline (A general reference for industry insights on IPF pathophysiology)
9. Cell-Cell Interaction Analysis in Progressive Idiopathic Pulmonary Fibrosis (IPF)
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates significant cell-cell interactions (CCIs) within the progressive_ipf condition using single-cell RNA sequencing data. The plot_cci_dots tool, leveraging CellPhoneDB results, visualizes the most prominent ligand-receptor (L-R) interactions between various immune cell types present in blood. The plot displays the top 80 interactions based on statistical significance (p-value) and interaction strength (mean expression), providing insights into the complex cellular communication networks active in progressive IPF.
Visual Summary
The dot plot visualizes cell-cell interactions for the progressive_ipf condition.
- Y-axis: Represents interacting cell pairs, where the first cell type is the "receiver" and the second is the "sender" (e.g., "T CD8+|T CD8+" indicates communication within CD8+ T cells).
- X-axis: Lists specific ligand-receptor gene pairs that mediate these interactions.
- Dot Size: Corresponds to the negative logarithm of the p-value (-log10(p)), indicating statistical significance. Larger dots signify more significant interactions (smaller p-values). A cut-off of pval_cutoff=0.05 was applied, meaning all shown interactions are statistically significant.
- Dot Color: Represents the logarithm (base 2) of the mean expression of the ligand-receptor pair (log2(m)), reflecting the interaction strength. A gradient from dark purple (low mean) to yellow/green (high mean) indicates varying interaction strengths. A mean_cutoff=0.01 was applied.
Key visual patterns observed:
- Monocytes are highly interactive: Monocytes (Mono) frequently appear as both sender and receiver in numerous significant interactions, often displaying strong mean expression values (yellow/green dots). Interactions involving Mono|Mono, Mono|T CD4+, Mono|NK, and Mono|B cell are particularly prominent.
- Prominent Ligand-Receptor Families: Several families of ligand-receptor interactions show widespread activity, including:
- Chemokine signaling: CCL3_CCR1, CCL5_CCR1 show strong interactions, particularly involving Monocytes, B cells, and NK cells.
- Annexin-Formyl Peptide Receptor (ANXA1-FPR1/FPR2): These interactions exhibit high significance and strong mean expression, especially between B cells and Monocytes (B cell|Mono).
- TNF Superfamily: Several members, such as CD160_TNFRSF14, TNFSF10_TNFRSF10A, and TNFSF13B_TNFRSF13B, mediate interactions across various T cell, NK cell, and Monocyte pairs.
- Integrins (ICAM1-integrin complexes): These adhesion molecules are broadly involved in interactions, particularly between T cells and Monocytes, suggesting extensive cell-cell adhesion and trafficking.
- Prostaglandin receptors: Various Prostaglandin-related interactions (e.g., ProstaglandinD2_byPTGDS_PTGDR, ProstaglandinE2_byPTGES3_PTGER2) show significant activity, often involving Monocytes.
- Immune checkpoint/MHC-related: CD47_SIRB1_complex and VSIR_HLA-E also display significant interactions.
- T cells and NK cells: Both CD4+ and CD8+ T cells, as well as NK cells, participate in diverse interactions, notably with Monocytes and amongst themselves.
Biological Interpretation
The analysis of cell-cell interactions in progressive IPF reveals a highly active and complex communication network, predominantly involving monocytes, T cells, NK cells, and B cells. These interactions are crucial for understanding the chronic inflammation and fibrotic remodeling characteristic of IPF.
- Monocyte-centric inflammatory hub: Monocytes, known for their plasticity and critical role in both initiating and resolving inflammation, appear as central players. Their strong interactions, especially via CCL3-CCR1 and CCL5-CCR1, highlight active chemokine signaling pathways that likely contribute to the recruitment and activation of other immune cells (T cells, NK cells) to the fibrotic lung. GeneCards: CCL3, GeneCards: CCL5, GeneCards: CCR1.
- Annexin A1 (ANXA1) and Formyl Peptide Receptors (FPRs): The strong ANXA1-FPR1/FPR2 interactions, particularly involving B cells and monocytes, are noteworthy. ANXA1 is typically associated with anti-inflammatory effects, but its interaction with FPRs can be context-dependent. In the chronic inflammatory environment of IPF, FPR activation on immune cells can contribute to inflammatory cell recruitment and even pro-fibrotic signaling. PubMed search: ANXA1 FPR fibrosis.
- Immune Adhesion and Trafficking: The widespread activity of ICAM1-integrin complexes indicates robust cell adhesion processes. ICAM1 is commonly upregulated during inflammation and facilitates immune cell migration and extravasation into tissues. This suggests ongoing immune cell trafficking and retention within the lung microenvironment in progressive IPF, contributing to sustained inflammation and fibrosis. GeneCards: ICAM1.
- TNF Superfamily Signaling: Various TNF superfamily interactions, such as CD160-TNFRSF14 (HVEM) and TNFSF10-TNFRSF10A (TRAIL-TRAILR), are active. These pathways are crucial for immune cell survival, proliferation, and apoptosis. Dysregulation can contribute to chronic inflammation and immune cell persistence. For example, TNFSF10 (TRAIL) can induce apoptosis, but also has non-apoptotic, pro-inflammatory functions in certain contexts. GeneCards: TNFRSF14, GeneCards: TNFSF10. The presence of TNFSF13B-TNFRSF13B (BAFF-BAFFR) interactions, particularly involving B cells, suggests a role in B cell survival and activation, which is increasingly recognized in IPF pathogenesis. GeneCards: TNFSF13B.
- Prostaglandin Signaling: Interactions involving Prostaglandin D2 (PTGDR) and Prostaglandin E2 (PTGERs) suggest the involvement of lipid mediators in modulating immune responses. Prostaglandins can have diverse effects on inflammation and fibrosis, acting as both pro- and anti-inflammatory agents depending on the specific receptor and cellular context. In IPF, they can influence fibroblast activation, collagen production, and immune cell function. PubMed search: Prostaglandin IPF.
- Immune Checkpoint Modulation: The presence of CD47-SIRPα complex and VSIR-HLA-E interactions indicates active immune regulatory mechanisms. CD47-SIRPα ("don't eat me" signal) prevents phagocytosis, and its dysregulation can impact macrophage efferocytosis (clearance of apoptotic cells), which is crucial in resolving inflammation. PubMed search: CD47 SIRPA fibrosis. VSIR (VISTA) is an immune checkpoint molecule, and its interaction with HLA-E can lead to immune suppression, potentially dampening protective anti-fibrotic immunity or contributing to chronic inflammation. PubMed search: VISTA HLA-E immune checkpoint.
Clinical or Translational Implications
The identified cell-cell interactions offer valuable insights for therapeutic target prioritization and experimental validation in progressive IPF:
- Targeting Chemokine Axes: Given the strong CCL3/CCL5-CCR1 interactions, blocking CCR1 or its ligands could reduce pathogenic immune cell recruitment (especially monocytes) to the lung, mitigating inflammation and fibrosis.
- Modulating Immune Cell Adhesion: Inhibiting ICAM1-integrin interactions could limit immune cell infiltration and adhesion within the fibrotic lung, thereby reducing the inflammatory burden.
- Interfering with B cell survival/activation: Targeting the BAFF-BAFFR (TNFSF13B-TNFRSF13B) axis could be a strategy to curb pathogenic B cell responses in IPF, potentially reducing autoantibody production and pro-fibrotic cytokine release.
- Re-evaluating Macrophage Function: The CD47-SIRPα pathway represents a potential target to restore proper efferocytosis by macrophages, which is often impaired in fibrotic diseases and contributes to the persistence of pro-fibrotic signals.
- Exploring Immune Checkpoint Blockade/Agonism: The VSIR-HLA-E interaction suggests that immune checkpoint modulation could be relevant. Further investigation could determine if inhibiting VSIR could re-invigorate beneficial anti-fibrotic immune responses or if agonism could dampen detrimental inflammation.
- Investigating Prostaglandin Pathways: Understanding the specific roles of prostaglandin receptors (PTGDR, PTGERs) in different immune cell types in IPF could pave the way for novel anti-inflammatory or anti-fibrotic therapies tailored to specific prostaglandin pathways.
These findings provide a mechanistic basis for designing targeted interventions to disrupt pathological cellular communication networks in progressive IPF, and warrant further experimental validation in relevant in vitro and in vivo models.
10. Immune Checkpoint Interactions Across IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates cell-cell interactions (CCI) specifically involving a curated set of immune checkpoint-related genes across different conditions: control, progressive idiopathic pulmonary fibrosis (IPF), and stable IPF. The goal is to identify how these specific immune regulatory interactions vary between healthy individuals and patients with different IPF disease courses, focusing on monocytes, T cells, and NK cells which are key players in immune responses in the blood and potentially in lung pathology. The plot_cci_dots tool was used to visualize significant ligand-receptor pairs, their interacting cell types, and their interaction strength.
Visual Summary
The visualizations present dot plots for three conditions (control, progressive IPF, stable IPF), showing cell-cell interactions mediated by immune checkpoint genes. Due to parameter settings, only statistically significant interactions are displayed.
- Identified Gene Pairs: Two specific ligand-receptor pairs are consistently observed across all conditions:
- CD86_CD28: A co-stimulatory pathway crucial for T cell activation.
- LGALS9_HAVCR2: An inhibitory immune checkpoint pathway (Galectin-9 and TIM-3).
- Interacting Cell Pairs: The analysis highlights interactions involving Monocytes with other immune cells and with themselves:
Monocyte | T cell CD4+
Monocyte | NK cell
Monocyte | Monocyte
- Statistical Significance: All depicted interactions are highly statistically significant, indicated by the uniformly large, black dots (representing a high -log10(p-value), likely above 10 based on the legend). This confirms the robust presence of these interactions.
- Interaction Strength (log2(mean)): The color of the dots represents the log2(mean) expression value, indicating the strength of the interaction. Subtle differences in these values are observed across conditions:
CD86-CD28 (Monocyte|T CD4+)
Control: log2(m) ~0.6
- Progressive IPF: log2(m) ~0.5 (Slightly reduced compared to control)
Stable IPF: log2(m) ~0.6 (Similar to control)
LGALS9-HAVCR2 (Monocyte|NK)
Control: log2(m) ~0.7
Progressive IPF: log2(m) ~0.7 (Similar to control)
- Stable IPF: log2(m) ~0.8 (Slightly increased compared to control)
LGALS9-HAVCR2 (Monocyte|Monocyte)
Control: log2(m) ~0.8
- Progressive IPF: log2(m) ~0.7 (Slightly reduced compared to control)
Stable IPF: log2(m) ~0.8 (Similar to control)
Biological Interpretation
The analysis specifically focuses on immune checkpoint interactions, which are critical for maintaining immune homeostasis and are often dysregulated in chronic inflammatory diseases like IPF.
- CD86-CD28 Co-stimulation: The interaction between Monocytes (likely presenting CD86) and CD4+ T cells (expressing CD28) is a fundamental co-stimulatory signal required for optimal T cell activation and differentiation [1]. The observation of a slightly reduced interaction strength in progressive IPF compared to control and stable IPF might suggest an altered T cell stimulatory environment in this more severe disease state. This could lead to suboptimal T cell responses or indicate a shift towards an exhausted or anergic T cell phenotype, which has implications for anti-fibrotic immunity.
- LGALS9-HAVCR2 (Galectin-9-TIM-3) Inhibitory Pathway: This axis represents a key inhibitory checkpoint that can dampen T cell and NK cell responses, contributing to immune evasion and tolerance [2].
- Monocyte|NK cell: An increased strength of LGALS9-HAVCR2 interaction in stable IPF suggests a potential enhancement of inhibitory signaling between monocytes and NK cells. This could contribute to the "stable" nature of the disease by suppressing pro-inflammatory or pro-fibrotic NK cell functions, or it could indicate an attempt by the immune system to resolve inflammation.
- Monocyte|Monocyte: The self-interaction of monocytes via LGALS9-HAVCR2 is interesting. A slight reduction in progressive IPF might indicate altered self-regulatory mechanisms within the monocyte population, potentially contributing to their pro-fibrotic or inflammatory phenotype. Monocytes are known to be highly plastic and contribute significantly to IPF pathogenesis through their differentiation into macrophages and fibroblasts.
These findings suggest that the delicate balance of immune checkpoints is altered in IPF, with distinct patterns emerging between stable and progressive disease, as well as compared to healthy controls.
Clinical or Translational Implications
The observed differences in immune checkpoint interactions between IPF conditions highlight potential areas for therapeutic intervention and further investigation:
- CD86-CD28 Axis in Progressive IPF: The subtle decrease in CD86-CD28 interaction in progressive IPF might suggest a state of T cell anergy or exhaustion. Strategies aimed at boosting T cell co-stimulation (e.g., agonistic CD28 antibodies, though safety is a concern) could theoretically enhance protective immune responses, but this would need careful consideration in the context of a fibrotic disease where immune overactivation could also be detrimental.
- LGALS9-HAVCR2 as a Therapeutic Target: The LGALS9-HAVCR2 pathway represents an attractive target for immunotherapy, similar to PD-1/PD-L1 or CTLA-4.
- The increased LGALS9-HAVCR2 interaction in stable IPF (Monocyte|NK) could indicate a mechanism of immune suppression. Inhibiting this pathway might release NK cells from suppression, potentially enhancing their anti-fibrotic or anti-tumor activity if relevant.
- Conversely, reduced LGALS9-HAVCR2 in progressive IPF (Monocyte|Monocyte) could imply a loss of monocyte self-regulation. Modulating this pathway could potentially restore regulatory functions or limit pro-fibrotic monocyte activity.
- Biomarker Potential: Changes in the strength of these specific immune checkpoint interactions could serve as potential biomarkers to differentiate between stable and progressive IPF, or to monitor treatment response.
- Experimental Validation: These findings warrant further experimental validation using techniques such as flow cytometry, immunohistochemistry, or functional co-culture assays to confirm the differential expression of these ligands and receptors and their functional consequences in IPF. Targeting these pathways in in vitro or in vivo IPF models could provide insights into their therapeutic potential.
References:
[1] CD86 (B7-2) GeneCards: A comprehensive gene-centric database. https://www.genecards.org/cgi-bin/carddisp.pl?gene=CD86
[2] TIM-3 (HAVCR2) GeneCards: A comprehensive gene-centric database. https://www.genecards.org/cgi-bin/carddisp.pl?gene=HAVCR2
11. Condition-specific Cell-Cell Interaction Patterns in Idiopathic Pulmonary Fibrosis (IPF)
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates statistically significant differences in cell-cell interactions (CCIs) among key immune cell types (T cell CD4+, T cell CD8+, Monocyte, NK cell, B cell, ILC, Neutrophil, Eosinophil, Platelet) in blood samples, comparing 'progressive_ipf', 'stable_ipf', and 'control' conditions. The dot plot visualizes the standardized mean interaction strength (color intensity) and the statistical significance (-log10(p-value) as dot size) for the top 25 most significant CCIs detected using a t-test based differential analysis with a p-value cutoff of 0.1, focusing on interactions that are 'greater' in one condition compared to others.
Visual Summary
The dot plot is structured to display individual samples along the y-axis, grouped by condition (Control, Progressive IPF, Stable IPF) on the top horizontal axis. The x-axis enumerates specific cell-cell interaction pairs (e.g., "Ligand-Receptor | Cell_A--Cell_B").
- Distinct Interaction Profiles by Condition:
- Control: Samples (C27-C40) show a baseline pattern of interactions, with several moderately strong and significant CCIs.
- Progressive IPF: Samples (P01-P26) exhibit a markedly different and often more intense pattern of CCIs. A prominent cluster of highly significant (large dots) and strong (dark red color) interactions is observed across many progressive IPF samples, particularly in the central portion of the plot. This suggests a widespread upregulation of specific immune cell crosstalk in this disease state.
- Stable IPF: Samples (S14-S26) generally show an intermediate or attenuated interaction profile compared to progressive IPF. While some interactions appear similar to those in progressive IPF, they are often less intense or less consistently significant across samples. Certain interactions are also unique to or more prominent in stable IPF compared to control, but less so than in progressive IPF.
- Dominant Cell Types in Interactions:
- A significant proportion of the highlighted CCIs involve Monocytes, frequently interacting with T cells (CD4+, CD8+), NK cells, and B cells. This suggests a central role for monocytes in orchestrating immune responses, particularly in IPF.
- T cells (CD4+ and CD8+) are also extensively involved, often as partners in interactions with monocytes or other immune cells.
- Key Interaction Gene Pairs:
- Several prostaglandin-related interactions, such as ProstaglandinE2 by PTGES2/3_PTGER4 with monocytes and T cells, are frequently observed, especially elevated in progressive IPF.
- Integrin-mediated interactions are also prominent, including ICAM2_integrin_aLb2_complex, PLAUR_integrin_a4b1_complex, and ICAM1_integrin_aLb2_complex, often involving T cells and monocytes.
- Interactions like LTA_TNFRSF1B and SEMA4D_PTPRC appear among the most significant in certain conditions.
Biological Interpretation
The observed patterns highlight substantial alterations in immune cell communication in the blood of IPF patients, particularly those with progressive disease.
- Monocyte-centric Immune Activation in Progressive IPF: The high frequency and intensity of monocyte-involved CCIs in progressive IPF suggest heightened monocyte activity and their critical role in the disease pathology. Monocytes are progenitors of macrophages, which are central effectors in fibrotic processes, influencing inflammation, tissue remodeling, and myofibroblast differentiation. Enhanced communication with T cells and other immune cells could lead to sustained pro-fibrotic or pro-inflammatory feedback loops PubMed search: monocytes macrophages fibrosis IPF.
- Prostaglandin E2 (PGE2) Signaling: Increased PGE2-related interactions (e.g., ProstaglandinE2 by PTGES2_PTGER4) in progressive IPF are notable. PGE2, produced by enzymes like PTGES2 and PTGES3, can have complex roles in fibrosis, acting as both an anti-inflammatory and, in some contexts, promoting fibrotic pathways through specific receptors (like PTGER4) GeneCards: PTGER4. Upregulated PGE2 signaling might indicate dysregulated immune dampening or direct pro-fibrotic signaling.
- Adhesion and Migration mediated by Integrins: The prevalence of integrin-mediated interactions (e.g., ICAM2_integrin_aLb2_complex, PLAUR_integrin_a4b1_complex) involving T cells and monocytes points towards altered cell adhesion, migration, and immune cell trafficking. Integrins are crucial for leukocyte extravasation into tissues and cell-cell recognition. Their increased activity could contribute to the recruitment of immune cells to sites of inflammation and fibrosis in the lung, even if detected systemically in the blood GeneCards: ICAM2. PLAUR (Urokinase Plasminogen Activator Receptor) in complex with integrins plays roles in cell migration and proteolytic activity, both relevant in tissue remodeling UniProt: PLAUR.
- T Cell-Mediated Immunomodulation: The involvement of CD4+ and CD8+ T cells in significant interactions, particularly with monocytes, indicates their active participation in the immune landscape of progressive IPF. T cells can drive fibrotic responses through cytokine production (e.g., Th2 cytokines) or regulatory functions (Tregs). Specific T-cell subsets are known to be dysregulated in IPF PubMed search: T cells IPF pathogenesis. LTA-TNFRSF1B signaling (lymphotoxin-alpha and its receptor) further suggests TNF-family-mediated inflammatory or immune modulatory pathways are active PubMed search: TNF family signaling fibrosis.
- Differentiation of Progressive vs. Stable Disease: The clear distinction in CCI patterns between progressive and stable IPF indicates that specific immune interactions might serve as biomarkers for disease progression. Stable IPF generally showing less intense or fewer specific interactions suggests a less active or different immunopathogenic process compared to progressive IPF.
Clinical or Translational Implications
- Prognostic Biomarkers: The unique and significantly upregulated cell-cell interaction signatures observed in progressive IPF could serve as promising blood-based prognostic biomarkers. Monitoring these specific interactions could help identify patients at higher risk of disease progression, guiding clinical management and therapeutic decisions.
- Therapeutic Targets: Key ligand-receptor pairs identified as highly active in progressive IPF, such as specific integrins or components of the PGE2 signaling pathway (e.g., PTGES2/3, PTGER4), represent potential therapeutic targets. Modulating these interactions could disrupt pro-fibrotic immune cascades and potentially halt or slow disease progression. For example, strategies targeting integrins have been explored in various fibrotic conditions.
- Disease Monitoring: Longitudinal assessment of these identified CCI patterns could provide a non-invasive method to monitor disease activity, response to existing therapies, or the efficacy of novel interventions in IPF patients.
12. Monocyte Condition-Specific Surfaceome Markers in IPF
[Analysis Visualization Results]...
This analysis identifies and visualizes key surfaceome markers that distinguish monocytes from individuals with stable Idiopathic Pulmonary Fibrosis (IPF) compared to healthy controls, derived from single-cell RNA sequencing data of blood. Identifying surface markers is particularly valuable for characterizing specific cell populations and exploring potential diagnostic or therapeutic targets, as these proteins are accessible on the cell surface.
Analysis Overview
The dot plot displays the expression levels and prevalence of selected surfaceome genes within Monocytes across different samples, grouped by condition: 'control' and 'stable_ipf'. Each row represents a sample, and each column represents a gene. The size of the dot indicates the fraction of monocytes in that sample expressing the gene, while the color intensity reflects the mean expression level of the gene in those cells. Only surfaceome markers, up to 50 per condition, were considered, and the plot shows a subset of these top markers.
Visual Summary
The dot plot clearly segregates samples based on condition and reveals distinct surfaceome marker profiles for monocytes:
- Control-specific Markers: A cluster of genes, including HBEGF, HCAR3, and AREG, shows notably higher expression levels and/or a greater fraction of expressing cells in monocytes from 'control' samples (e.g., C27, C32, C31) compared to 'stable_ipf' samples. These markers are significantly diminished or absent in the 'stable_ipf' group.
- Stable IPF-specific Markers: Conversely, several genes, including HLA-DQA2, AQP9, HLA-G, FPR2, FFAR2, and STEAP4, exhibit elevated expression and/or prevalence in monocytes from 'stable_ipf' samples (e.g., S20, S17, S26, S25, S22, S18) compared to controls. This group of markers appears to define a distinct monocyte state associated with stable IPF.
- Heterogeneity within groups: While clear condition-specific patterns emerge, there is some sample-to-sample variability within both the control and stable IPF groups, indicating potential individual differences in monocyte immune phenotypes.
- Sample Cell Counts: The bar plot on the right indicates the number of monocytes per sample, which varies, but does not appear to directly influence the observed gene expression patterns.
Biological Interpretation
The distinct surfaceome profiles observed in monocytes between control and stable IPF conditions point towards altered immune functions, metabolic states, and regulatory roles of these cells in IPF pathogenesis.
- Monocytes in IPF: Monocytes and macrophages are critical players in IPF, contributing to inflammation, tissue remodeling, and fibrosis. The blood compartment serves as a reservoir for monocytes that can infiltrate the lungs and differentiate into various macrophage subtypes.
Control-Associated Markers (HBEGF, HCAR3, AREG):
- HBEGF (Heparin-binding EGF-like growth factor) and AREG (Amphiregulin) are both ligands for the EGF receptor (EGFR). They are generally involved in cell proliferation, migration, and tissue repair. Their higher expression in control monocytes might signify a homeostatic or regenerative capacity in healthy individuals. The reduction in IPF could suggest impaired repair mechanisms or a shift away from these functions. GeneCards: HBEGF GeneCards: AREG
- HCAR3 (Hydroxycarboxylic acid receptor 3) is a G protein-coupled receptor activated by niacin and its metabolites, known to mediate anti-inflammatory effects. Its prominence in control monocytes could indicate a role in maintaining immune quiescence or regulating inflammation in healthy states. GeneCards: HCAR3
Stable IPF-Associated Markers (HLA-DQA2, AQP9, HLA-G, FPR2, FFAR2, STEAP4):
- HLA-DQA2 is an MHC class II molecule, indicating altered antigen presentation capacity in IPF monocytes. Upregulation might suggest increased immune activation or altered immune recognition in the disease context. GeneCards: HLA-DQA2
- HLA-G is a non-classical MHC class I molecule often associated with immune tolerance, capable of suppressing T cell and NK cell responses. Its upregulation in stable IPF monocytes could reflect an attempt by the immune system to dampen excessive inflammation or, conversely, a mechanism by which pathological immune responses persist through immunosuppression. GeneCards: HLA-G
- AQP9 (Aquaporin 9) is a water/glycerol channel. Its expression on immune cells can be involved in cell migration, cytokine production, and oxidative stress responses. Upregulation could imply altered metabolic activity or migratory potential of monocytes in IPF. GeneCards: AQP9
- FPR2 (Formyl peptide receptor 2) is a G protein-coupled receptor involved in inflammatory processes, phagocytosis, and cell migration. Its role can be complex, mediating both pro- and anti-inflammatory effects. Elevated FPR2 could indicate a dysregulated inflammatory response or altered efferocytosis in IPF monocytes. GeneCards: FPR2
- FFAR2 (Free fatty acid receptor 2) is activated by short-chain fatty acids (SCFAs) and plays a role in modulating inflammation and metabolism. Upregulation could point to altered metabolic sensing and inflammatory regulation, potentially influenced by systemic changes in gut microbiota or diet in IPF patients. GeneCards: FFAR2
- STEAP4 (STEAP4 metalloreductase) is involved in lipid metabolism, adipogenesis, and inflammatory signaling. Its increased expression might suggest a shift in the metabolic programming or redox state of monocytes, which can influence their pro-fibrotic or inflammatory functions. GeneCards: STEAP4
Clinical or Translational Implications
These distinct monocyte surfaceome marker profiles hold significant potential for clinical and translational applications:
- Biomarkers for Disease Stratification and Monitoring: The clear differentiation of stable IPF from controls based on these surface markers suggests their potential as non-invasive biomarkers. These could be measured in peripheral blood monocytes (e.g., via flow cytometry) to aid in the diagnosis of IPF, distinguish it from other lung diseases, or monitor disease stability. Specifically, a panel combining markers like HLA-DQA2, HLA-G, or FPR2 could offer insights into the immune state associated with stable IPF.
- Therapeutic Targets: As these are surface proteins, they are amenable to targeted therapeutic interventions. For instance:
- Modulating the activity of FPR2 or FFAR2 could influence the inflammatory and metabolic state of monocytes, potentially altering their contribution to fibrosis.
- Targeting HLA-G might be considered if its expression is found to contribute to immune evasion by pathogenic cells or dysfunctional tolerance in IPF.
- Exploring ways to restore the expression of control-associated markers like HBEGF or AREG might promote beneficial tissue repair pathways.
- Understanding Monocyte Phenotypes: These markers can help define specific monocyte subsets that are active or altered in stable IPF. Further research using these markers could lead to a deeper understanding of the specific roles these monocyte populations play in the disease and identify their unique functional contributions.
- Validation: These findings warrant further validation through orthogonal methods such as flow cytometry or mass cytometry on a larger cohort of IPF patients (including progressive IPF) and controls. Functional studies would also be crucial to elucidate the precise roles of these surface proteins in monocyte behavior and their contribution to IPF pathogenesis.
13. CD4+ T Cell Surfaceome Marker Analysis Across IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis aimed to identify condition-specific surfaceome markers for CD4+ T cells, comparing progressive_ipf, stable_ipf, and control conditions from single-cell RNA-seq data obtained from blood tissue. The plot_markers_and_expression_dot tool was used to visualize the expression of these markers. The analysis was specifically configured to find up to 50 surfaceome-only markers per condition, with strict cutoffs for score, p-value, and fold change (e.g., fc_cutoff=1.5, pval_cutoff=0.05). Markers common to three or more groups were configured to be removed, emphasizing specificity.
Visual Summary
The provided dot plot visualizes the expression of two genes, TNFRSF4 and LPAR6, across individual samples categorized by condition (inferred as progressive_ipf, stable_ipf, and control based on the data context and visual grouping, although specific condition labels are not fully visible).
- Marker Expression (Color Intensity): The color intensity of each dot represents the mean expression level of the gene within CD4+ T cells for that specific sample. For both TNFRSF4 and LPAR6, the dots are predominantly faint red or light-colored, indicating generally low mean expression levels across almost all samples and conditions shown.
- Fraction of Expressing Cells (Dot Size): The size of each dot corresponds to the fraction of CD4+ T cells in that sample that express the gene. Similarly, the dots are consistently small, suggesting that only a small proportion of CD4+ T cells express TNFRSF4 or LPAR6 across the samples.
- Sample Cell Counts: A bar plot on the right displays the total number of CD4+ T cells detected in each sample, ranging from low counts (e.g., C30 with 171 cells) to higher counts (e.g., S21 with 1005 cells). The expression patterns do not appear to be overtly biased by the number of cells in the samples for these two genes.
- Condition Specificity: Based on the visual evidence for TNFRSF4 and LPAR6, there is no clear pattern of differential expression or significant upregulation in any single condition (progressive_ipf, stable_ipf, or control) compared to the others. Both genes show consistently low expression and low fraction of expressing cells across all observed samples, suggesting they do not serve as strong *condition-specific markers* based on this visualization.
It is important to note that while the analysis was configured to find up to 50 condition-specific surfaceome markers, the provided visualization displays only these two genes. This could imply that very few markers met the stringent criteria for condition-specificity and surfaceome localization, or that the visualization itself has limited the display to these two.
Biological Interpretation
Despite not showing strong condition-specific differences in this particular visualization, the identified genes warrant a brief biological consideration in the context of CD4+ T cells and IPF:
- TNFRSF4 (OX40): This gene encodes OX40, a co-stimulatory receptor primarily expressed on activated CD4+ T cells. Engagement of OX40 by its ligand, OX40L (TNFSF4), provides a critical secondary signal that promotes T cell proliferation, survival, cytokine production, and differentiation into memory cells. Dysregulation of OX40-OX40L signaling is implicated in various inflammatory and autoimmune diseases. In the context of Idiopathic Pulmonary Fibrosis (IPF), T cells are known contributors to the chronic inflammation and fibrotic processes. Even if not highly expressed or differentially expressed in this specific blood single-cell dataset, its presence on CD4+ T cells highlights a potential immunomodulatory axis that could be relevant in the lung microenvironment or at other disease stages.
- Reference: GeneCards: TNFRSF4
- Reference: PubMed search for OX40 T cell IPF
- LPAR6 (Lysophosphatidic Acid Receptor 6): LPAR6 is a G protein-coupled receptor for lysophosphatidic acid (LPA), a bioactive lipid mediator. LPA signaling plays diverse roles in cell proliferation, migration, differentiation, and survival, and is widely implicated in fibrotic diseases, including lung fibrosis. While LPA's effects on immune cells are broad, LPAR6 is not as commonly studied in T cells as other LPARs. Its detection, even at low levels, on CD4+ T cells suggests a potential responsiveness of these cells to lipid signaling pathways that are known to be active in fibrotic conditions. This could imply a role for CD4+ T cells in sensing and responding to the lipid-rich microenvironment often associated with IPF progression.
- Reference: GeneCards: LPAR6
- Reference: PubMed search for LPA LPAR fibrosis lung
Clinical or Translational Implications
Based solely on the visual output for TNFRSF4 and LPAR6, this analysis does not readily identify strong, distinct condition-specific surfaceome markers for CD4+ T cells in the blood that could serve as robust diagnostic or therapeutic targets for progressive or stable IPF.
- Limited Marker Utility: The observed low and non-differential expression of TNFRSF4 and LPAR6 in this visualization suggests that these two particular genes, as presented, may not be ideal candidates for distinguishing IPF conditions or for targeted therapeutic intervention specifically based on their differential expression on blood CD4+ T cells.
- Further Investigation Needed: To comprehensively assess condition-specific markers, it would be crucial to review the complete list of markers identified by the find_cfg parameters (if more than two were identified) and potentially visualize them if they met the initial discovery criteria but were filtered out by plotting parameters. If no other markers were found, this might suggest that robust condition-specific surfaceome markers for CD4+ T cells in blood are rare or require different analytical parameters (e.g., less stringent fold change or p-value cutoffs, or focusing on other cell populations/tissues).
- Contextual Relevance: Although not visually differential here, the biological roles of OX40 and LPA signaling are well-established in immunology and fibrosis. If other analyses (e.g., CCI, GSEA, GSA not shown here) point to the involvement of these pathways, even subtle changes in their expression or activity could be mechanistically important and warrant further investigation in the lung tissue.
14. Cell Cycle Pathway Gene Expression Differences in CD4+ T cells Across IPF Conditions
[Analysis Visualization Results]...
Analysis Overview
This analysis investigates the differential expression of a panel of cell cycle pathway-related genes in CD4+ T cells, comparing peripheral blood samples from control individuals, patients with progressive idiopathic pulmonary fibrosis (IPF), and patients with stable IPF. The goal is to identify genes with statistically significant expression differences that may be associated with IPF disease status and progression. The box plots display gene expression levels (sample mean) for each condition, with p-values indicating statistical significance between groups.
Visual Summary
The visualization presents box plots for nine key cell cycle-related genes: CCND3, YWHAB, MYC, RBX1, MAD1L1, ANAPC11, SKP1, YWHAZ, and ANAPC5. All nine genes consistently show elevated expression in CD4+ T cells from patients with progressive IPF compared to control individuals.
Key observations include:
- Upregulation in Progressive IPF vs. Control: All displayed genes (CCND3, YWHAB, MYC, RBX1, MAD1L1, ANAPC11, SKP1, YWHAZ, ANAPC5) exhibit statistically significant (p ≤ 0.1) higher expression in CD4+ T cells from progressive IPF patients compared to control samples. For instance, MYC and RBX1 show very strong significance (p ≤ 0.01 and p ≤ 0.001, respectively).
- Progressive IPF vs. Stable IPF Differences: A notable trend is the higher expression of several genes in progressive IPF compared to stable IPF. Specifically, YWHAB (p = 0.07), MYC (p = 0.09), MAD1L1 (p = 0.10), ANAPC11 (p = 0.10), YWHAZ (p = 0.10), and ANAPC5 (p ≤ 0.05) are either significantly or borderline significantly upregulated in progressive IPF compared to stable IPF.
- Stable IPF vs. Control: For most genes, expression levels in stable IPF CD4+ T cells are not significantly different from controls (p > 0.1). This suggests that the observed cell cycle dysregulation is primarily associated with the progressive form of the disease.
Biological Interpretation
The consistent upregulation of these cell cycle genes in CD4+ T cells from progressive IPF patients strongly suggests an altered proliferative state or dysregulated cell cycle control in these immune cells. Many of the genes observed play critical roles in driving cell division:
- CCND3 (Cyclin D3): A key G1 cyclin that promotes progression from G1 to S phase. Its upregulation points towards enhanced cell cycle entry and proliferation. https://www.genecards.org/cgi-bin/carddisp.pl?gene=CCND3
- MYC: A proto-oncogene and a master regulator of cell growth, proliferation, and metabolism. Increased MYC expression is a hallmark of highly proliferative cells. https://www.genecards.org/cgi-bin/carddisp.pl?gene=MYC
- RBX1 (RING-Box 1), ANAPC11 (Anaphase Promoting Complex Subunit 11), ANAPC5 (Anaphase Promoting Complex Subunit 5), SKP1 (S-Phase Kinase Associated Protein 1): These genes are components of ubiquitin ligase complexes (SCF and APC/C) that are crucial for targeted degradation of cell cycle regulatory proteins, thereby promoting cell cycle progression, DNA replication, and mitotic exit. Their increased expression suggests an acceleration of cell cycle machinery. https://www.genecards.org/cgi-bin/carddisp.pl?gene=RBX1 https://www.genecards.org/cgi-bin/carddisp.pl?gene=ANAPC11 https://www.genecards.org/cgi-bin/carddisp.pl?gene=ANAPC5 https://www.genecards.org/cgi-bin/carddisp.pl?gene=SKP1
- YWHAB and YWHAZ (14-3-3 proteins): These proteins act as chaperones and regulators of diverse cellular processes, including cell cycle progression and DNA damage response, often by binding to phosphorylated proteins. Their upregulation can modulate T cell activity and survival. https://www.genecards.org/cgi-bin/carddisp.pl?gene=YWHAB https://www.genecards.org/cgi-bin/carddisp.pl?gene=YWHAZ
- MAD1L1 (Mitotic Arrest Deficient 1 Like 1): A component of the spindle assembly checkpoint (SAC). While SAC components typically restrain mitosis, their upregulation can also signify increased mitotic activity or a cellular response to overcome proliferation checkpoints. https://www.genecards.org/cgi-bin/carddisp.pl?gene=MAD1L1
In the context of IPF, a chronic and progressive fibrotic lung disease, T cells are known to contribute to both pro- and anti-fibrotic responses. The observed increased expression of cell cycle activators in circulating CD4+ T cells specifically in progressive IPF suggests an expansion of activated, proliferating T cell subsets. This heightened proliferative state in progressive disease could contribute to chronic inflammation, immune dysregulation, and ultimately, accelerated fibrogenesis within the lung, as these activated cells may migrate to the affected tissue and perpetuate the fibrotic cascade.
Clinical or Translational Implications
- Biomarkers for Disease Progression: The differential expression of these cell cycle genes in CD4+ T cells, particularly the distinction between progressive and stable IPF, suggests their potential as biomarkers. Monitoring the expression of genes like MYC, YWHAB, and ANAPC5 in peripheral blood CD4+ T cells could help identify patients at higher risk of disease progression or assess response to therapies.
- Therapeutic Targets: The observed activation of cell cycle pathways in T cells during progressive IPF indicates that modulating T cell proliferation and activation could be a viable therapeutic strategy. Targeting key drivers like MYC, or specific components of the ubiquitin ligase complexes (e.g., RBX1, SKP1, ANAPC subunits), might offer novel approaches to dampen detrimental T cell responses without broad immunosuppression. For instance, MYC inhibition is an active area of research for various proliferative disorders, including inflammatory conditions. https://pubmed.ncbi.nlm.nih.gov/search/?term=MYC+inhibition+fibrosis
- Pathogenic Mechanisms: These findings provide insights into the underlying immune mechanisms driving IPF progression, highlighting a specific dysregulation in the cell cycle of CD4+ T cells that correlates with worsening disease. Further investigation into the specific T cell subsets undergoing this proliferation and their functional characteristics could lead to a deeper understanding of IPF pathogenesis.
15. Gene Set Enrichment Analysis Reveals Condition-Specific Pathway Alterations Across Immune Cell Types in Idiopathic Pulmonary Fibrosis
[Analysis Visualization Results]...
Analysis Overview
This analysis utilizes Gene Set Enrichment Analysis (GSEA) to identify biological pathways that are significantly enriched or depleted in various immune cell populations (B cell, ILC, Monocyte, NK cell, Neutrophil, Platelet, T cell CD4+, T cell CD8+) from the blood of patients with Idiopathic Pulmonary Fibrosis (IPF) at different disease stages (progressive IPF, stable IPF) compared to control subjects. The dot plot visualizes the Normalized Enrichment Score (NES) and the significance (-log10(p-value)) for the top 80 enriched pathways, providing insights into the molecular mechanisms driving cell-state shifts in IPF.
Visual Summary
The dot plot displays an intricate landscape of pathway enrichments and depletions across different immune cell types and disease conditions.
- Color Scale (NES): Red dots indicate pathways enriched (upregulated activity) in the specific condition (e.g., "progressive_ipf vs others"), while blue dots indicate depleted pathways (downregulated activity). The color intensity reflects the magnitude of the NES.
- Dot Size (-log(p-val)): Larger dots represent more statistically significant enrichment or depletion (smaller p-values).
General Patterns:
- Many pathways show a differential enrichment pattern between control samples and IPF samples (both progressive and stable), with control often showing depletion (blue) where IPF conditions show enrichment (red), and vice versa.
- There is a clear distinction in pathway activity between progressive_ipf and stable_ipf for several cell types, although some pathways show similar trends across both IPF conditions.
- Monocytes, Neutrophils, T cell CD4+, and T cell CD8+ cells show the most widespread and pronounced pathway alterations, particularly in progressive_ipf.
Biological Interpretation
The GSEA results highlight significant shifts in immune cell function and metabolism, particularly in progressive IPF.
Inflammatory and Immune Activation Pathways
- TNF Signaling Pathway: This pathway is notably enriched across multiple cell types (Monocyte, NK cell, Neutrophil, T cell CD4+, T cell CD8+, Platelet) in progressive_ipf_vs_others and stable_ipf_vs_others. This suggests a sustained pro-inflammatory environment in IPF, with TNF-alpha playing a central role in immune cell activation and crosstalk, which is well-documented in fibrotic diseases. PubMed: TNF fibrosis
- IL-17 Signaling Pathway: Enriched in Monocyte and T cell CD4+ in progressive_ipf_vs_others and stable_ipf_vs_others. This indicates a significant involvement of Th17 cells and IL-17-mediated inflammation, known to contribute to fibrosis and autoimmune responses.
- NOD-like Receptor Signaling Pathway: Shows enrichment in Monocyte and Neutrophil in progressive_ipf_vs_others, suggesting activation of innate immune sensing pathways that can trigger inflammation.
- T cell Receptor Signaling Pathway: Enriched in T cell CD4+ (progressive and stable IPF) and T cell CD8+ (stable IPF), but interestingly depleted in T cell CD8+ (progressive IPF). This complex pattern might indicate different states of T cell activation, exhaustion, or anergy depending on the T cell subset and disease progression.
- B cell Receptor Signaling Pathway: Enriched in B cell in both progressive_ipf_vs_others and stable_ipf_vs_others, pointing towards B cell activation which can contribute to autoimmune features and inflammation in IPF.
- Th1 and Th2 Cell Differentiation: A clear shift towards Th2 cell differentiation (enriched) in T cell CD4+ (progressive IPF), accompanied by a depletion of Th1 cell differentiation in T cell CD4+ (progressive and stable IPF). This Th2-skewed immune response is a hallmark of fibrotic diseases like IPF, promoting fibroblast activation and collagen deposition. PubMed: Th1 Th2 fibrosis
Metabolic and Cellular Processes
- Oxidative Phosphorylation: Consistently enriched across Monocytes, NK cells, Neutrophils, and T cells (CD4+ and CD8+) in progressive_ipf_vs_others. This suggests increased metabolic activity and energy demand in these immune cells, possibly reflecting their activated state or a shift towards oxidative metabolism to support pro-inflammatory and pro-fibrotic functions. PubMed: oxidative phosphorylation immune cell activation
- Autophagy: Enriched in Monocyte, NK cell, Neutrophil, and T cell CD4+ in progressive_ipf_vs_others. Dysregulation of autophagy is increasingly recognized in IPF pathogenesis, affecting cell survival, inflammation, and fibroblast activation. PubMed: autophagy IPF
- Ribosome: Enriched in Monocyte, NK cell, Neutrophil, T cell CD4+, and T cell CD8+ in progressive_ipf_vs_others. This indicates increased protein synthesis, consistent with cellular activation, proliferation, or increased production of inflammatory mediators.
- Lipid and Atherosclerosis: Enriched in Monocyte, Neutrophil, and Platelet in progressive_ipf_vs_others. This suggests altered lipid metabolism, which can influence immune cell function and contribute to inflammatory and fibrotic processes.
Disease Progression Specificity
- Monocytes in Progressive IPF: Monocytes from progressive_ipf patients show a particularly strong and broad enrichment of pro-inflammatory (TNF, IL-17, NOD-like receptor), metabolic (Oxidative phosphorylation, Lipid), and cellular stress (Autophagy, p53 signaling) pathways. This underscores their critical role in orchestrating the inflammatory and fibrotic responses in advanced IPF. PubMed: monocyte IPF
- PD-L1 Expression and PD-1 Checkpoint Pathway: Enriched in Monocyte (progressive IPF), NK cell (stable IPF), and T cell CD4+ (progressive IPF). This suggests potential immune evasion mechanisms or an attempt to regulate the heightened inflammation, which could be exploited in immunotherapy strategies.
- Platelets in Progressive IPF: Platelets show enrichment in Lipid and atherosclerosis and Vascular smooth muscle contraction pathways in progressive_ipf_vs_others. Platelets are known to release various profibrotic and pro-inflammatory mediators, contributing to disease progression. PubMed: platelet fibrosis
Clinical or Translational Implications
The distinct pathway enrichments observed in progressive_ipf patients, especially in monocytes and T cells, provide valuable insights into the mechanisms driving disease progression.
- Biomarker Discovery: Pathways like TNF signaling, IL-17 signaling, Oxidative phosphorylation, and Autophagy could serve as targets for monitoring disease activity or progression. Changes in gene expression within these pathways in specific immune cell types could be explored as circulating biomarkers.
- Therapeutic Targets: The observed activation of TNF, IL-17, and NOD-like receptor signaling pathways suggests that targeting these inflammatory axes could be beneficial in IPF. Modulating metabolic reprogramming (e.g., oxidative phosphorylation) or autophagy in specific immune cell populations could represent novel therapeutic strategies to halt fibrosis progression.
- Immune Modulation: The shift towards Th2 responses and the activation of PD-1 checkpoint pathway highlight the potential for immunomodulatory therapies. Understanding the specific roles of different T cell subsets and monocytes in driving fibrosis could lead to more targeted immune interventions.
- Disease Heterogeneity: The cell-type-specific pathway alterations underscore the complex and heterogeneous nature of IPF. Future studies could investigate how these findings correlate with patient clinical outcomes and therapeutic responses.
16. Discussion
This comprehensive single-cell analysis of peripheral blood provides critical insights into the systemic immune landscape of Idiopathic Pulmonary Fibrosis (IPF), distinguishing between control, stable, and progressive disease states. The findings underscore a profound immune dysregulation that likely contributes to disease progression.
First, significant shifts in peripheral immune cell populations were observed. Monocytes are notably expanded in progressive IPF patients compared to controls and stable IPF, with their proportion increasing from control to stable to progressive disease. This suggests a heightened systemic inflammatory state, as monocytes are crucial precursors to pro-fibrotic macrophages known to infiltrate the lung in IPF. Furthermore, B cell proportions also appeared increased in both stable and progressive IPF compared to controls, highlighting potential involvement of humoral immunity in IPF pathogenesis. Within T cell subsets, progressive IPF showed increased proportions of Th22 and, notably, Th2 cells, which are well-established contributors to fibrosis, contrasting with reduced Th17 cells in both IPF conditions compared to controls. This Th2-skewed response, also supported by GSEA, suggests a systemic shift towards pro-fibrotic immune profiles, while NK cells were increased in stable IPF, potentially reflecting compensatory immune activation.
Monocytes exhibit a distinct phenotypic reprogramming in IPF. Stable IPF monocytes show upregulation of surface markers such as HLA-DQA2, AQP9, HLA-G, FPR2, FFAR2, and STEAP4, contrasting with genes like HBEGF, HCAR3, and AREG in control monocytes. This signature indicates an altered activation, metabolic state, and antigen-presentation capacity, likely contributing to chronic inflammation and tissue remodeling. For instance, increased FPR2 and FFAR2 suggest altered sensing of inflammatory mediators and metabolic changes, respectively.
CD4+ T cells in progressive IPF display signs of increased proliferative activity. A panel of cell cycle-related genes, including CCND3, YWHAB, MYC, RBX1, MAD1L1, ANAPC11, SKP1, YWHAZ, and ANAPC5, showed significant upregulation in CD4+ T cells from progressive IPF patients compared to controls. This heightened proliferative state in progressive disease could contribute to chronic inflammation, immune dysregulation, and ultimately, accelerated fibrogenesis, as these activated cells may migrate to the affected tissue and perpetuate the fibrotic cascade.
Cell-cell interaction (CCI) analysis reveals a highly active and complex communication network in progressive IPF, predominantly involving monocytes, T cells, NK cells, and B cells. Key interaction families include chemokine signaling (CCL3/CCL5-CCR1), Annexin-Formyl Peptide Receptor (ANXA1-FPR1/FPR2), integrin-mediated adhesion (ICAM1/2-integrin), TNF superfamily (e.g., BAFF-BAFFR), and prostaglandin receptors (e.g., PGE2-PTGER4). These interactions suggest robust immune cell adhesion, trafficking, and a pro-inflammatory milieu. Immune checkpoint analysis highlighted subtle but significant changes, with CD86-CD28 interactions between monocytes and CD4+ T cells slightly reduced in progressive IPF, potentially indicating T cell anergy or exhaustion. Conversely, the inhibitory LGALS9-HAVCR2 (Galectin-9-TIM-3) pathway showed increased strength in stable IPF (Monocyte|NK) and a slight reduction in progressive IPF (Monocyte|Monocyte), suggesting dynamic shifts in immune regulatory mechanisms.
Gene Set Enrichment Analysis (GSEA) further corroborates these findings, showing widespread activation of pro-inflammatory pathways (TNF signaling, IL-17 signaling, NOD-like receptor signaling) across multiple immune cell types in both IPF conditions, especially progressive IPF. Metabolic pathways like oxidative phosphorylation and lipid metabolism, along with cellular stress responses such as autophagy and ribosome biogenesis, are also enriched, indicating increased metabolic demands and protein synthesis in activated immune cells. The observed shift towards Th2 cell differentiation in progressive IPF CD4+ T cells and the enrichment of PD-L1 expression/PD-1 checkpoint pathway in monocytes and CD4+ T cells from progressive IPF suggest immune evasion mechanisms and a pro-fibrotic environment.
Hypotheses:
- Increased circulating monocyte populations, especially those with an activated and metabolically reprogrammed phenotype, actively drive the progression of Idiopathic Pulmonary Fibrosis (IPF) through enhanced pro-fibrotic signaling and recruitment to the lung.
- A shift in the peripheral T cell balance towards a Th2-skewed, proliferative state, coupled with dysregulated immune checkpoint interactions, contributes to the chronic inflammation and extracellular matrix deposition characteristic of progressive IPF.
- Specific cell-cell interaction axes, such as those involving chemokines (CCL3/5-CCR1) and integrins (ICAM1/2-integrin) with monocytes and T cells, are critical mediators of immune cell recruitment and activation that sustain fibrotic processes in progressive IPF.
Potential therapeutic targets:
- CCR1 and its ligands (CCL3/CCL5): CCR1 is strongly involved in monocyte recruitment and activation, which drives inflammation and fibrosis in IPF. Blocking this axis could reduce pathogenic immune cell infiltration to the lung. Evidence: High significance and strong mean expression in cell-cell interaction analysis, particularly involving Monocytes, B cells, and NK cells in progressive IPF (Section 9). Validation: Test CCR1 antagonists in IPF animal models and monitor monocyte migration/activation; assess in patient trials for reduced disease progression markers.
- FPR2 and FFAR2 receptors on Monocytes: These receptors are significantly upregulated in stable IPF monocytes, suggesting their involvement in altered inflammatory sensing and metabolic reprogramming. Modulating their activity could reprogram monocyte function, potentially dampening pro-fibrotic responses. Evidence: Identified as key stable IPF-specific monocyte surfaceome markers (Section 3, 12). Validation: Use specific agonists/antagonists of FPR2 and FFAR2 in *in vitro* monocyte differentiation assays and *in vivo* fibrosis models to evaluate their impact on pro-fibrotic functions.
- MYC (in CD4+ T cells): MYC is a master regulator of cell proliferation and is significantly upregulated in CD4+ T cells in progressive IPF, indicating an expanded, activated T cell population. Inhibiting MYC could dampen detrimental T cell responses. Evidence: Upregulated cell cycle gene expression, including MYC, in CD4+ T cells from progressive IPF patients (Section 14). Validation: Evaluate MYC inhibitors in *in vitro* T cell proliferation assays and *in vivo* IPF models to assess effects on T cell expansion and fibrotic markers.
- BAFF-BAFFR axis (TNFSF13B-TNFRSF13B): The BAFF-BAFFR axis is active in B cell survival and activation, which contributes to autoimmune features and inflammation in IPF. Targeting this axis could curb pathogenic B cell responses. Evidence: Significant interaction identified in cell-cell interaction analysis, particularly involving B cells (Section 9). Validation: Test BAFF/BAFFR inhibitors in animal models of fibrosis and in patient studies to assess impacts on B cell activity and disease progression.
- TNF Signaling Pathway: Consistently enriched across multiple immune cell types in both stable and progressive IPF, indicating a sustained pro-inflammatory environment that contributes to fibrotic disease. Evidence: Gene Set Enrichment Analysis (GSEA) shows widespread enrichment of TNF signaling pathway across Monocytes, NK cells, Neutrophils, T cell CD4+, T cell CD8+, and Platelets in both IPF conditions (Section 15). Validation: Evaluate existing TNF-alpha inhibitors or novel agents targeting specific components of the TNF signaling cascade in IPF models and clinical trials.
Follow-up validation ideas:
- Perform *in vitro* and *ex vivo* functional assays to validate the functional consequences of altered monocyte surface markers (e.g., FPR2, FFAR2) and their interaction with ligands on immune cell migration, differentiation, and cytokine production using patient-derived monocytes.
- Utilize multiplexed protein assays such as flow cytometry or mass cytometry (CyTOF) on peripheral blood and bronchoalveolar lavage (BAL) samples to validate surface marker expression (e.g., HLA-DQA2, AQP9, FPR2) and confirm T cell subset proportions (e.g., Th2, Th22, Th17, NK cells) at the protein level.
- Employ *in vivo* animal models of pulmonary fibrosis to test the therapeutic efficacy of targeting key pathways (e.g., blocking CCR1, inhibiting MYC, modulating specific immune checkpoints) identified by GSEA and CCI analyses.
- Conduct longitudinal patient studies to correlate changes in peripheral blood monocyte proportions, T cell subset shifts, and GSEA pathway activity with clinical outcomes (e.g., lung function decline, radiological progression) in IPF patients.
- Apply spatial transcriptomics and/or proteomics technologies to IPF lung tissue to confirm the localization and functional relevance of identified cell types and cell-cell interactions in the disease microenvironment.
Limitations:
The analysis is primarily based on peripheral blood, which reflects systemic immune responses but may not fully capture the local immune environment and cellular interactions within the fibrotic lung tissue. The functional relevance of some blood-based findings may differ locally. Population bar plots present relative proportions, not absolute cell counts, meaning an increase in one cell type might relatively decrease others without necessarily reflecting absolute changes. A small fraction of cells remains 'unassigned,' potentially representing rare or transient cell states that warrant further investigation. For some cell types (e.g., CD4+ T cells), robust condition-specific surfaceome markers were scarce or showed very low expression in the blood, potentially limiting their utility as strong biomarkers or targets. While GSEA and CCI analyses highlight enriched pathways and interactions, the precise functional impact and specificity of these changes in driving fibrosis versus other inflammatory processes require further mechanistic validation.
17. Query List
- Show UMAPs including condition, sample, major cell type, minor cell type, and celltype_subset in 2 columns and save.
- Show expression of CD3D, CD4, CD8A, CD79A, CD14, LYZ, NKG7, S100A9, ITGA2B genes on UMAP along with minor cell type annotation. Set ncols=3 and save.
- Show the overall Celltype_subset marker expression dot plot and save it. Keep target_cell as None and keep the other arguments at their default values.
- Show a population bar plot of minor cell types and save.
- Show a subset population bar plot for T cells and save.
- Show a subset population bar plot for Monocytes and save.
- Show box plots for statistically significant differences in T cell subset populations between conditions and save. Set ncols appropriately based on the total number of panels.
- Show box plots for statistically significant differences in Monocyte subset populations between conditions and save. Set ncols appropriately based on the total number of panels.
- Show cell-cell interactions by condition and save the result. Select at most 80 cell-cell interactions for each condition.
- Show cell-cell interactions using only genes related to immune checkpoint and cell cycle pathways and save.
- Find statistically significant differences in cell-cell interactions among T cell CD4+, T cell CD8+, Monocyte, NK cell, B cell, ILC, Neutrophil, Eosinophil, Platelet cell types by condition and show them as a dot plot, then save. Set max_n_items_per_group = 25.
- Extract condition-specific markers for Monocytes and show them as a dot plot, then save. Include only surfaceome markers, up to 50 per condition.
- Extract condition-specific markers for T cell CD4+ and show them as a dot plot, then save. Include only surfaceome markers, up to 50 per condition.
- For T cell CD4+, Monocyte, and B cell, show box plots for statistically significant differences in expression of cell cycle pathway related genes by condition, and save. Set max_n_items_to_plot = 24 and ncols appropriately so the aspect ratio is about 2x3.
- Show Gene set enrichment analysis results as a dot plot for B cell, ILC, Monocyte, NK cell, Neutrophil, Platelet, T cell CD4+, T cell CD8+. Set the color map to RdBu_r and n_pws_to_show = 80, then save.













