Details for: CL1001567

Cell ID: CL1001567

Cell Name: lung endothelial cell

Description: Any endothelial cell of vascular tree that is part of some lung.

Synonyms: endothelial cell of lung, pulmonary vessel endothelial cell

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 lung endothelial cell 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 lung endothelial cell. 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 lung endothelial cell. 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 lung endothelial cell. 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:  lung endothelial cell (CL1001567)

 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 [lung endothelial cell](/details-cell/CL1001567) is a fundamental component of the pulmonary vasculature, forming the critical interface between blood and the lung parenchyma. Based on gene significance analysis, the **Overall** defining characteristic of this cell type is an exceptionally high level of metabolic and biosynthetic activity. The top markers are not canonical endothelial-specific genes but are dominated by factors involved in protein translation ([TPT1](/details-gene/7178)), glycolysis ([GAPDH](/details-gene/2597)), and RNA processing ([PABPC1](/details-gene/26986)). This suggests that the primary role and unique identity of lung endothelial cells, relative to other lung cell types, are centered on their function as highly active "workhorse" cells, likely necessary to maintain the vast and physiologically demanding capillary network of the lung. ## Key Characteristics and Function The gene expression profile of [lung endothelial cells](/details-cell/CL1001567) highlights several core functional axes. * **Intense Protein Synthesis and Metabolism:** A large proportion of the top markers are involved in fundamental cellular processes. Genes like [TPT1](/details-gene/7178) (translationally controlled tumor protein), [PABPC1](/details-gene/26986) (poly(A) binding protein), [EEF1B2](/details-gene/1933) (eukaryotic translation elongation factor), and [NPM1](/details-gene/4869) (nucleophosmin) underscore a high capacity for protein synthesis. This is energetically supported by the high specificity of genes involved in glycolysis ([GAPDH](/details-gene/2597)) and mitochondrial respiration ([ATP5F1E](/details-gene/514), [ND4](/details-gene/4538)), indicating robust energy production to fuel their biosynthetic and barrier-maintenance functions. * **RNA Processing and Regulation:** The high significance of multiple heterogeneous nuclear ribonucleoproteins ([HNRNPU](/details-gene/3192), [HNRNPA2B1](/details-gene/3181)) and RNA helicases ([DDX5](/details-gene/1655)) points to extensive post-transcriptional regulation. This suggests that lung endothelial cells employ complex mechanisms of mRNA splicing, stability, and transport to fine-tune their proteome in response to the dynamic lung microenvironment. * **Immune Surveillance Interface:** The high z-scores for [B2M](/details-gene/567) (Beta-2-microglobulin) and the non-classical MHC class I molecule [HLA E](/details-gene/3133) are notable. This indicates that a key specific function of these cells is antigen presentation. The prominence of [HLA E](/details-gene/3133), which primarily interacts with NK cell and activated T-cell inhibitory receptors, suggests a specialized role in modulating immune responses and maintaining tolerance at the blood-air barrier. * **Iron Homeostasis:** The strong signature of ferritin light chain ([FTL](/details-gene/2512)) and heavy chain ([FTH1](/details-gene/2495)) suggests a significant role in iron sequestration and management. In the high-oxygen environment of the lung, this function may be critical for mitigating oxidative stress by safely storing reactive iron. * **Anti-Markers:** The analysis reveals that several canonical endothelial markers, such as the receptor tyrosine kinase [TEK](/details-gene/7010) (Tie2) and the gap junction protein [GJA4](/details-gene/2701), are among the least significant genes. This does not imply their absence but indicates that their expression is not a uniquely defining feature of these cells in the context of the entire lung tissue. Instead, the cell's identity appears to be overwhelmingly dominated by its high metabolic and biosynthetic state rather than its specialized vascular signaling machinery. ## Clinical Significance and Contextual Roles **Overall**, the gene profile of [lung endothelial cells](/details-cell/CL1001567) points to their central role in both homeostasis and pathology. Their high metabolic rate makes them potentially vulnerable to metabolic insults and oxidative stress, key factors in lung injury and diseases like acute respiratory distress syndrome (ARDS). The strong immune signature conferred by [B2M](/details-gene/567) and [HLA E](/details-gene/3133) positions these cells as critical players in pulmonary infections and inflammation. Dysregulation of their antigen presentation machinery could contribute to failed viral clearance or autoimmune-mediated damage. For instance, changes in [HLA E](/details-gene/3133) expression could alter the activation threshold of NK cells, impacting the innate immune response to pathogens or transformed cells. Furthermore, the presence of [ITM2B](/details-gene/9445) as a marker, a gene associated with a form of familial dementia through protein aggregation ([Link](https://doi.org/10.1038/21637)), is unexpected. While its function in the lung is unclear, it may hint at a role for endothelial cells in processing or clearing amyloidogenic proteins, a process that could be relevant in age-related lung diseases or systemic amyloidosis. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The defining transcriptional signature of [lung endothelial cells](/details-cell/CL1001567) is a state of "constitutive activation" characterized by exceptionally high basal metabolism and protein synthesis, which is essential for maintaining the vast surface area and integrity of the pulmonary capillary network, rather than the expression of specific angiogenic or junctional markers. * **Surprising Findings:** The most significant finding is that well-established endothelial-specific genes like [TEK](/details-gene/7010), [RASIP1](/details-gene/54922), and [GJA4](/details-gene/2701) are ranked as anti-markers or have very low specificity. This challenges the conventional view of what defines an endothelial cell at the transcriptional level in a complex tissue, suggesting that metabolic phenotype can be a more dominant identifier than lineage-specific signaling receptors. * **Testable Questions:** Does selective inhibition of glycolysis (e.g., targeting [GAPDH](/details-gene/2597)) or protein synthesis compromise the barrier function of pulmonary microvascular endothelial cells more severely than endothelial cells from other vascular beds (e.g., aorta, brain) under basal conditions? 2. **Hypothesis:** [Lung endothelial cells](/details-cell/CL1001567) serve as specialized sentinels for the immune system, primarily through the [HLA E](/details-gene/3133) pathway, to continuously signal tissue health and modulate the activity of circulating NK cells and cytotoxic T lymphocytes at the blood-air interface. * **Surprising Findings:** While expression of MHC class I components like [B2M](/details-gene/567) is expected, the high specificity of the non-classical molecule [HLA E](/details-gene/3133) is particularly noteworthy. It suggests a shift in focus from conventional foreign antigen presentation to a more nuanced immunomodulatory role focused on regulating innate and adaptive lymphocyte activation, making it a distinguishing feature of these cells. * **Testable Questions:** In a co-culture system, does silencing [HLA E](/details-gene/3133) expression on human [lung endothelial cells](/details-cell/CL1001567) lead to increased NK cell degranulation and cytotoxicity, particularly under sub-lethal inflammatory or viral stress conditions?