Details for: CL4033043

Cell ID: CL4033043

Cell Name: lung interstitial macrophage

Description: A macrophage that is part of the lung connective tissue (pulmonary interstitium). This cell performs tissue remodeling and contributes to barrier immunity through antigen presentation.

Synonyms: lung IM

Selected Context(s): Overall

Gene Significance Landscape

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Score:
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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 interstitial macrophage 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 interstitial macrophage. 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 interstitial macrophage. 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 interstitial macrophage. 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 interstitial macrophage (CL4033043)

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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 [lung interstitial macrophage](/details-cell/CL4033043) is a myeloid cell residing within the connective tissue of the lung, where it is described to perform tissue remodeling and contribute to barrier immunity via antigen presentation. The gene significance profile suggests this cell type possesses a highly specialized metabolic state, distinguished by the exceptional specific expression of [SAT1](/details-gene/6303), the rate-limiting enzyme in polyamine catabolism. This, combined with high expression of genes involved in managing oxidative stress ([GSTP1](/details-gene/2950)), immune signaling ([CXCR4](/details-gene/7852), [TYROBP](/details-gene/7305)), and post-transcriptional regulation ([NEAT1](/details-gene/283131)), indicates a cell that is metabolically poised to perform robust homeostatic and immune surveillance functions within the delicate lung microenvironment. ## Key Characteristics and Function **Overall**, the gene expression landscape of the [lung interstitial macrophage](/details-cell/CL4033043) points to a cell with a sophisticated and multi-faceted functional profile, defined by several key biological themes. * **Myeloid Lineage and Immune Readiness:** The cell's identity as a macrophage is strongly supported by the specific expression of the myeloid transcription factor [SPI1](/details-gene/6688) (PU.1) and pan-leukocyte marker [PTPRC](/details-gene/5788) (CD45). Its role in immunity is further underscored by high CSI scores for genes critical to immune signaling and function. These include [B2M](/details-gene/567), a component of the MHC class I molecule essential for antigen presentation to [CD8-positive, alpha-beta T cells](/details-cell/CL0000625) ([Link](https://pubmed.ncbi.nlm.nih.gov/3312414/)); [TYROBP](/details-gene/7305) (DAP12), an activating signal-transducing adaptor for numerous receptors on myeloid cells ([Link](https://doi.org/10.1038/35642)); [CXCR4](/details-gene/7852), a chemokine receptor vital for cell trafficking; and [AIF1](/details-gene/199) (Iba1), a well-established marker for macrophage activation and microglial cells ([Link](https://doi.org/10.1006/bbrc.1996.1612)). Other notable myeloid-associated markers include [MNDA](/details-gene/4332) and [MS4A7](/details-gene/58475). * **Specialized Polyamine and Redox Metabolism:** The most distinguishing feature of this cell is the top-ranking significance of [SAT1](/details-gene/6303) (spermidine/spermine N1-acetyltransferase). As the rate-limiting enzyme in polyamine catabolism, its prominence suggests this pathway is central to the cell's function, potentially regulating proliferation, differentiation, and inflammatory responses. This high metabolic activity appears coupled with a robust capacity to manage oxidative stress, evidenced by the high significance of [GSTP1](/details-gene/2950) (glutathione S-transferase Pi 1) and [PRDX1](/details-gene/5052) (peroxiredoxin 1). Furthermore, the high expression of [ALDH1A1](/details-gene/216), involved in retinoic acid synthesis, points to immunomodulatory roles through vitamin A metabolism. * **Post-Transcriptional and Nuclear Regulation:** A significant investment in post-transcriptional gene regulation is suggested by the high CSI scores for [PABPC1](/details-gene/26986), a key poly(A)-binding protein that influences mRNA stability and translation, and [NEAT1](/details-gene/283131), a long non-coding RNA that is an essential structural component of nuclear paraspeckles. This suggests these cells may utilize paraspeckle formation and mRNA management to rapidly modulate their protein expression in response to environmental cues. * **Energy and Cytoskeletal Functions:** Consistent with an active phagocytic and motile cell, the profile shows significant expression of genes related to energy production ([ATP5F1E](/details-gene/514)) and cytoskeletal function ([MYL6](/details-gene/4637)), which are necessary for tissue surveillance and cellular remodeling. The **Anti-Markers** provide further insight, indicating what this cell is *not* specialized in compared to others. The negative CSI for numerous general RNA binding proteins ([HNRNPC](/details-gene/3183), [CIRBP](/details-gene/1153)) and splicing factors ([SRSF5](/details-gene/6430)) contrasts with the high specificity of [PABPC1](/details-gene/26986) and [NEAT1](/details-gene/283131), reinforcing the idea of a specialized, rather than generalized, system of post-transcriptional control. Similarly, the low specific expression of the antioxidant enzyme [SOD1](/details-gene/6647) may indicate a preferential reliance on glutathione-based pathways ([GSTP1](/details-gene/2950)) for managing oxidative stress. ## Clinical Significance and Contextual Roles While this analysis is based on an **Overall** context, the specific gene signature of [lung interstitial macrophages](/details-cell/CL4033043) has significant implications for lung health and disease. The central role of polyamine metabolism, highlighted by [SAT1](/details-gene/6303), is particularly relevant. Polyamines are essential for cell growth, and their dysregulation is implicated in inflammation and cancer. High [SAT1](/details-gene/6303) activity in these macrophages could be a key mechanism for controlling inflammation in the lung, either by depleting pro-proliferative polyamines or by generating byproducts like hydrogen peroxide that have signaling roles. The strong expression of detoxification and antioxidant genes like [GSTP1](/details-gene/2950) suggests these cells are well-equipped to protect the lung interstitium from inhaled toxins and endogenous oxidative damage generated during inflammation. This protective function is critical in conditions like chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF). The high significance of immune modulators such as [CXCR4](/details-gene/7852) and [AIF1](/details-gene/199) positions these cells as key players in immune responses within the lung. [CXCR4](/details-gene/7852) is a known co-receptor for HIV and is involved in cell trafficking in both inflammation and cancer metastasis. The expression of [AIF1](/details-gene/199), a marker of macrophage activation, suggests this population could be a major contributor to inflammatory lung diseases, including acute respiratory distress syndrome (ARDS) or sarcoidosis. The expression of [TYROBP](/details-gene/7305) further implicates these cells in driving potent inflammatory responses through various activating receptors. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The highly specific expression of [SAT1](/details-gene/6303) establishes polyamine catabolism as a core metabolic program in [lung interstitial macrophages](/details-cell/CL4033043), which functions to control their inflammatory state and redox balance within the lung tissue. This pathway may act as a rheostat, where its activity dictates whether the macrophage adopts a pro-inflammatory or a tissue-remodeling phenotype. * **Surprising Findings:** It is highly unusual for a metabolic enzyme involved in polyamine catabolism to be the top defining marker of a tissue-resident macrophage population, ranking higher than canonical immune genes. This suggests a unique metabolic adaptation to the lung environment. The co-expression of robust antioxidant systems ([GSTP1](/details-gene/2950)) alongside a potentially ROS-generating pathway ([SAT1](/details-gene/6303)) points to a tightly controlled redox system. * **Testable Question:** How does pharmacological inhibition of [SAT1](/details-gene/6303) in primary human [lung interstitial macrophages](/details-cell/CL4033043) alter their metabolic flux, cytokine secretion profile, and phagocytic capacity in response to stimulation with bacterial ligands (e.g., LPS) or fibrotic mediators (e.g., TGF-beta)? 2. **Hypothesis:** The [lung interstitial macrophage](/details-cell/CL4033043) leverages a specialized post-transcriptional regulatory network, centered on [NEAT1](/details-gene/283131)-dependent paraspeckles and [PABPC1](/details-gene/26986)-mediated mRNA stabilization, to maintain a state of immune readiness. This allows for the rapid translation of a specific subset of inflammatory and remodeling-associated transcripts upon detection of danger signals, without requiring de novo transcription. * **Surprising Findings:** The high rank of a structural long non-coding RNA, [NEAT1](/details-gene/283131), as a specific cell type marker is unexpected. It implies that the dynamic assembly and disassembly of paraspeckles are not a generic cellular stress response but rather an integral part of this macrophage's specialized function and identity. The contrast with the low specificity of many other RNA-binding proteins further highlights the specialized nature of this regulatory axis. * **Testable Question:** Does conditional knockout of [NEAT1](/details-gene/283131) in a mouse model of lung interstitial macrophages lead to altered localization of key immune transcription factors or the destabilization of specific mRNAs (e.g., for cytokines or chemokines) following a viral lung infection, and does this impact viral clearance and lung injury?