Details for: CL0000057

Cell ID: CL0000057

Cell Name: fibroblast

Description: These cells may be vimentin-positive, fibronectin-positive, fsp1-positive, MMP-1-positive, collagen I-positive, collagen III-positive, and alpha-SMA-negative.

Selected Context(s): Overall

Gene Significance Landscape

Display Options
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 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. 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. 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. 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 (CL0000057)

 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.

Loading network (please wait)...

## Summary The [fibroblast](/details-cell/CL0000057) is a mesenchymal cell type characterized by its contribution to the synthesis of the extracellular matrix, including collagen and fibronectin. **Overall**, the gene significance profile, based on expression specificity (Z-score), reveals that fibroblasts are not merely structural cells but are highly active in protein synthesis, cellular metabolism, and immune surveillance. The high specificity scores for genes involved in protein translation ([`EEF1B2`](/details-gene/1933)), antigen presentation ([`B2M`](/details-gene/567)), and cell adhesion ([`CDH19`](/details-gene/28513)) underscore its multifaceted role in maintaining tissue homeostasis and responding to environmental cues. Notably, the most specific marker, [`PGM5P3 AS1`](/details-gene/101929127), and the third most specific marker, the long non-coding RNA [`NEAT1`](/details-gene/283131), point towards complex and potentially uncharacterized regulatory networks governing fibroblast identity and function. ## Key Characteristics and Function The top-ranking genes for [fibroblasts](/details-cell/CL0000057) highlight several core functional clusters that define this cell type's identity. * **High Biosynthetic and Metabolic Activity:** A prominent group of top markers is associated with protein synthesis and modification. This includes multiple translation elongation factors such as [`EEF1B2`](/details-gene/1933) and [`EEF1D`](/details-gene/1936), the poly(A)-binding protein [`PABPC1`](/details-gene/26986), and the ubiquitin-coding gene [`UBC`](/details-gene/7316). The high specificity of these genes suggests that fibroblasts maintain a robust machinery for protein production, consistent with their primary role in secreting large quantities of extracellular matrix proteins like [`COL6A2`](/details-gene/1292), which also appears as a significant marker. Genes involved in cellular metabolism and stress response, such as the ferritin light chain [`FTL`](/details-gene/2512) for iron storage and glutathione S-transferase [`GSTP1`](/details-gene/2950) for detoxification, further underscore the cell's high metabolic turnover. * **Structural Integrity and Cell Adhesion:** As expected, genes related to structural roles are defining features. The cadherin [`CDH19`](/details-gene/28513), involved in cell-cell communication and morphogenesis, shows a very high specificity score (CSI-Z: 22.28). This, along with the significance of [`COL6A2`](/details-gene/1292), confirms the classical function of fibroblasts in establishing and maintaining tissue architecture. * **Immune Interaction and Signaling:** The high specificity of Beta-2-microglobulin ([`B2M`](/details-gene/567)), an essential component of MHC class I molecules, is particularly noteworthy. It suggests that fibroblasts play a crucial role in presenting endogenous antigens to the immune system, acting as potential sentinels within tissues. Furthermore, the significant expression of the immediate early gene [`FOS`](/details-gene/2353) and the calcium-binding protein [`S100A6`](/details-gene/6277) indicates that fibroblasts are highly responsive to extracellular stimuli, capable of rapidly altering their transcriptional programs. * **Negative Markers and Metabolic Profile:** The list of anti-markers provides critical insight into what is *not* a defining feature of fibroblasts. The negative Z-scores for multiple core components of the mitochondrial electron transport chain, including [`COX1`](/details-gene/4512), [`COX2`](/details-gene/4513), [`COX3`](/details-gene/4514), and [`ATP6`](/details-gene/4508), are striking. This does not imply low expression, but rather that high oxidative phosphorylation is not a uniquely specific characteristic of fibroblasts compared to other cell types. This may suggest a reliance on other metabolic pathways, such as aerobic glycolysis, to fuel their high biosynthetic demands. ## Clinical Significance and Contextual Roles The gene expression profile of [fibroblasts](/details-cell/CL0000057) points to their deep involvement in a wide range of physiological and pathological processes. The role of fibroblasts extends far beyond simple tissue scaffolding. The specific expression of [`B2M`](/details-gene/567) positions them as active participants in immune surveillance, with potential implications for autoimmune diseases, cancer immunology, and response to infection. Dysregulation of fibroblast-mediated antigen presentation could contribute to either the breakdown of self-tolerance or immune evasion by tumors. Several top marker genes are directly implicated in human disease. For instance, mutations in [`COL6A2`](/details-gene/1292) are associated with congenital muscular dystrophies. The high specificity of the cardiac ryanodine receptor [`RYR2`](/details-gene/6262), typically associated with [cardiac muscle cells](/details-cell/CL0000746), is unexpected and may suggest a role for fibroblasts in cardiac arrhythmias and cardiomyopathy, potentially through paracrine signaling or direct electromechanical coupling in the heart. Similarly, the marker [`ITM2B`](/details-gene/9445) is linked to familial British and Danish dementias ([Link](https://doi.org/10.1038/21637), [Link](https://doi.org/10.1073/pnas.080076097)), suggesting a potential contribution of central nervous system fibroblasts or perivascular fibroblasts to neurodegenerative processes. The proto-oncogene [`FOS`](/details-gene/2353) as a specific marker highlights the fibroblast's potential for transformation and its well-established role in the tumor microenvironment as cancer-associated fibroblasts (CAFs), which are known to promote tumor growth, invasion, and therapeutic resistance. ## Potential Mechanisms and Research Directions 1. **Hypothesis: Fibroblasts act as dynamic tissue sentinels that integrate microenvironmental signals and communicate them to the adaptive immune system.** The data suggest that fibroblasts are not passive structural cells but are poised to respond to tissue stress. The high specificity of the immediate-early transcription factor [`FOS`](/details-gene/2353) indicates a capacity for rapid transcriptional reprogramming in response to stimuli, while the high specificity of [`B2M`](/details-gene/567) provides the machinery to translate this intracellular state into an extracellular signal for T-lymphocytes via MHC-I presentation. * **Surprising Findings:** The ranking of [`B2M`](/details-gene/567), an immune-related gene, as the second most specific protein-coding marker for a cell traditionally defined by its structural role is unexpected and re-frames the fibroblast as a semi-professional antigen-presenting cell. * **Testable Questions:** In a co-culture model, does stimulation of fibroblasts with pro-inflammatory cytokines (e.g., IFN-gamma) or damage-associated molecular patterns lead to an increase in surface MHC-I expression and subsequent activation of antigen-specific [CD8-positive, alpha-beta T cells](/details-cell/CL0000625)? 2. **Hypothesis: The defining metabolic signature of fibroblasts is skewed towards aerobic glycolysis rather than oxidative phosphorylation to support their high biosynthetic needs.** This hypothesis is based on the strong negative specificity scores for multiple essential genes of the mitochondrial electron transport chain ([`COX1`](/details-gene/4512), [`COX2`](/details-gene/4513), [`ATP6`](/details-gene/4508)). This pattern is characteristic of the Warburg effect, where cells favor glycolysis even in the presence of oxygen. This metabolic state provides the necessary anabolic precursors (e.g., for amino acid and nucleotide synthesis) required for the rapid proliferation and high protein secretion characteristic of activated fibroblasts during wound healing or in the tumor microenvironment. * **Surprising Findings:** It is counterintuitive that core components of cellular respiration are "anti-markers" for a cell type with such a high energy demand for extracellular matrix production. This suggests that metabolic pathway preference, rather than just total energy output, is a key aspect of fibroblast identity. * **Testable Questions:** What is the relative contribution of glycolysis versus oxidative phosphorylation to ATP production in fibroblasts under basal and stimulated (e.g., with TGF-beta) conditions, as measured by a Seahorse XF metabolic flux analyzer?