Details for: CL0002553

Cell ID: CL0002553

Cell Name: fibroblast of lung

Description: A fibroblast that is part of lung.

Selected Context(s): Overall

Gene Significance Landscape

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Score:
Display
Genes

Contexts:

Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for fibroblast of lung within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for fibroblast of lung. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for fibroblast of lung. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for fibroblast of lung. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

Maximum number of selected genes.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  fibroblast of lung (CL0002553)

 Legend
Nodes (Genes):
 Query Gene
Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
 Very High
 High
 Medium
 Low
 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

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## Summary The [fibroblast of lung](/details-cell/CL0002553) is a mesenchymal cell type integral to the structure and homeostasis of the lung parenchyma. Based on its gene significance profile, this cell is characterized by exceptionally high and specific expression of genes involved in iron metabolism, antigen presentation, and protein synthesis. The prominence of [B2M](/details-gene/567) as a top marker suggests these fibroblasts are not merely structural scaffolds but may also serve as active participants in immune surveillance within the lung microenvironment. Furthermore, the high specificity of ferritin subunits ([FTH1](/details-gene/2495) and [FTL](/details-gene/2512)) points to a specialized role in managing iron homeostasis and mitigating oxidative stress in the oxygen-rich pulmonary context. ## Key Characteristics and Function **Overall**, the gene expression landscape of the lung fibroblast highlights its role as a metabolically active, homeostatic cell with significant immunomodulatory potential. The top marker genes can be organized into several key functional clusters: * **Immune System Interaction and Antigen Presentation:** The most specific marker, Beta-2-microglobulin ([B2M](/details-gene/567), CSI: 102.35), is an essential component of the MHC class I molecule. This strongly suggests that lung fibroblasts are constitutively engaged in presenting endogenous antigens, a critical process for immune surveillance by cytotoxic [T cells](/details-cell/CL0000084), particularly in the context of viral infections or malignancy. * **Iron Metabolism and Oxidative Stress Response:** Two of the top five markers are Ferritin Heavy Chain 1 ([FTH1](/details-gene/2495), CSI: 101.24) and Ferritin Light Chain ([FTL](/details-gene/2512), CSI: 97.99). Ferritin is the primary intracellular iron storage protein, and its high specificity indicates that lung fibroblasts play a crucial role in sequestering iron to prevent the formation of reactive oxygen species via the Fenton reaction. This function is further supported by the high significance of [GSTP1](/details-gene/2950), which is involved in detoxifying reactive oxygen species. * **High Translational and Proteostatic Activity:** A large number of top markers are associated with protein synthesis, folding, and degradation. These include ubiquitin genes ([UBC](/details-gene/7316), [UBB](/details-gene/7314)), translation elongation factors ([EEF1D](/details-gene/1936), [EEF1B2](/details-gene/1933)), and components of the signal recognition particle ([SRP14](/details-gene/6727)). This profile is consistent with the fibroblast's primary function of synthesizing and remodeling the extracellular matrix, indicating a high level of protein turnover and quality control. * **Calcium Signaling and Cytoskeletal Regulation:** The high significance of [S100A6](/details-gene/6277), a calcium-binding protein, and [MYL6](/details-gene/4637), a myosin light chain, underscores the importance of calcium-dependent signaling pathways and cytoskeletal dynamics. These functions are central to fibroblast activities such as migration, contraction, and mechanotransduction. The anti-markers for this cell type further refine its identity. The lack of significance for hematopoietic cytokines like [CSF3](/details-gene/1440) or specific developmental markers like [PHEX](/details-gene/5251) confirms its distinct mesenchymal lineage, distinguishing it from immune cells and other specialized cell types within the lung. ## Clinical Significance and Contextual Roles Given that this analysis represents an **Overall** context, the top markers suggest potential roles for lung fibroblasts in a variety of pathological states. The highly specific expression of ferritin genes ([FTH1](/details-gene/2495) and [FTL](/details-gene/2512)) positions these cells as central players in diseases characterized by iron dysregulation and oxidative stress, such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD). Aberrant iron handling by fibroblasts could contribute to a pro-fibrotic microenvironment through excess oxidative damage. The role of lung fibroblasts in immunity, highlighted by [B2M](/details-gene/567) expression, is clinically significant. During viral infections (e.g., influenza, SARS-CoV-2), these fibroblasts could act as a reservoir of viral antigen presentation, potentially contributing to the recruitment and activation of cytotoxic T lymphocytes. Conversely, in lung cancer, their antigen presentation machinery could be co-opted by tumors to induce T-cell exhaustion or could be targeted by immunotherapies to enhance anti-tumor responses. Furthermore, the significance of [NPM1](/details-gene/4869), which is encoded by an mRNA from interferon-treated cells ([Link](https://pubmed.ncbi.nlm.nih.gov/2478125/)), reinforces the cell's capacity to respond to inflammatory and anti-viral signals. The gene [ITM2B](/details-gene/9445) is associated with amyloid-beta binding and familial British dementia ([Link](https://doi.org/10.1038/21637)), and its specific expression in lung fibroblasts may suggest a role in local protein aggregation or clearance processes in the lung, which could be relevant in age-related lung diseases. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** Lung fibroblasts function as a critical iron-buffering system in the pulmonary interstitium, sequestering free iron to protect against oxygen toxicity and regulate local inflammation. * **Surprising Findings:** It is notable that genes for iron metabolism ([FTH1](/details-gene/2495), [FTL](/details-gene/2512)) exhibit higher expression specificity than many canonical fibroblast markers (e.g., collagens). This suggests that iron handling is a more defining and specialized function for this cell type than previously appreciated, possibly distinguishing it from fibroblasts in other, less oxygen-rich tissues. * **Testable Questions:** Does conditional knockout of [Fth1](/details-gene/2495) in murine lung fibroblasts exacerbate lung injury and fibrosis in response to hyperoxic or bleomycin-induced challenges? 2. **Hypothesis:** Lung fibroblasts act as significant non-professional antigen-presenting cells (APCs) that directly shape the local CD8+ T-cell response during pulmonary infections and cancer. * **Surprising Findings:** The status of [B2M](/details-gene/567) as the single most specific gene marker for a structural cell is unexpected. This finding elevates the fibroblast from a passive bystander in adaptive immunity to a potential front-line participant, capable of directly "displaying" the intracellular health of the lung parenchyma to the immune system. * **Testable Questions:** Using an *in vitro* co-culture system, can human lung fibroblasts pulsed with a defined viral or tumor peptide trigger antigen-specific proliferation and cytokine production (e.g., IFN-γ) from autologous CD8+ [T cells](/details-cell/CL0000084)?