Details for: CL1000909

Cell ID: CL1000909

Cell Name: kidney loop of Henle epithelial cell

Description: Any nephron tubule epithelial cell that is part of some loop of Henle.

Selected Context(s): Overall

Gene Significance Landscape

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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 kidney loop of Henle epithelial 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 kidney loop of Henle epithelial 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 kidney loop of Henle epithelial 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 kidney loop of Henle epithelial 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:  kidney loop of Henle epithelial cell (CL1000909)

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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 [kidney loop of Henle epithelial cell](/details-cell/CL1000909) is a specialized cell type within the nephron tubule, critical for creating the concentration gradient in the renal medulla. The gene significance profile for this cell, **Overall**, is dominated by an exceptionally strong signature of genes involved in mitochondrial energy production and aerobic respiration. This suggests that its primary physiological function—the active transport of ions to facilitate water reabsorption—is supported by a remarkably high and specific metabolic engine. The specific expression of [UMOD](/details-gene/7369), a key protein in renal water homeostasis and innate immunity, further solidifies its identity as a distinct and highly specialized renal cell type. ## Key Characteristics and Function Analysis of top marker genes, ranked by expression specificity (`csi_z`), reveals several core functional clusters that define the [kidney loop of Henle epithelial cell](/details-cell/CL1000909). * **Intense Mitochondrial and Metabolic Activity:** The most prominent characteristic is a profound enrichment for genes encoding components of the mitochondrial respiratory chain and ATP synthesis. This includes numerous subunits of cytochrome c oxidase ([COX6C](/details-gene/1345), [COX7C](/details-gene/1350), [COX4I1](/details-gene/1327), [COX5B](/details-gene/1329)), NADH:ubiquinone oxidoreductase ([NDUFA4](/details-gene/4697)), and ATP synthase ([ATP5F1B](/details-gene/506), [ATP5MG](/details-gene/10632)). The high specificity of genes like [LDHB](/details-gene/3945) and [ENO1](/details-gene/2023) further underscores a reliance on energetic metabolic pathways. This metabolic machinery is consistent with the high ATP demand required to power the ion pumps essential for the kidney's countercurrent multiplication mechanism. * **Ion Transport and Homeostasis:** The cell's primary function is directly supported by the specific expression of [ATP1B1](/details-gene/481), the beta subunit of the Na+/K+-ATPase pump, which is fundamental for active ion transport across the epithelial barrier. Furthermore, the high significance of [UMOD](/details-gene/7369) (Uromodulin), which is involved in renal water homeostasis and ion channel regulation, highlights a specialized role in maintaining fluid and electrolyte balance ([Link](https://doi.org/10.1126/science.3453112)). * **Immune Surveillance and Cell Identity:** The top-ranked gene by specificity is [B2M](/details-gene/567), a component of MHC class I molecules. While broadly expressed, its high `csi_z` score in this context may suggest a specialized role in antigen presentation or an unexpected level of immune interaction within this nephron segment. The significance of [UMOD](/details-gene/7369) also points to a role in the organ-specific immune response, as it is known to prevent urinary tract infections by binding to pathogens ([Link](https://doi.org/10.1126/science.3498215)). * **Detoxification and Cytoprotection:** The specific expression of [GSTP1](/details-gene/2950), a glutathione S-transferase, indicates a capacity for cellular detoxification, protecting the cell from oxidative stress and xenobiotics, a critical function within the kidney. * **Structural and Housekeeping Functions:** Genes such as [MYL6](/details-gene/4637) (myosin light chain) suggest maintenance of the specialized cell shape required for tubular architecture. The high specificity of ubiquitin ([UBB](/details-gene/7314)) and ferritin ([FTL](/details-gene/2512)) points to robust protein turnover and iron management systems, respectively, necessary for a metabolically active cell. The anti-marker profile lacks genes specific to other renal segments or non-epithelial lineages, confirming the distinct identity of this cell type. For instance, the low significance of genes like [CLCNKB](/details-gene/1188), which is more prominently expressed in the distal tubule, helps differentiate this cell's specific location within the nephron. ## Clinical Significance and Contextual Roles The gene signature of the [kidney loop of Henle epithelial cell](/details-cell/CL1000909) provides insights into its potential role in renal disease. The most clinically relevant marker is [UMOD](/details-gene/7369). Mutations in this gene are directly causative for autosomal dominant tubulointerstitial kidney disease (ADTKD), formerly known as medullary cystic kidney disease 2 and familial juvenile hyperuricaemic nephropathy ([Link](https://doi.org/10.1136/jmg.39.12.882)). The high specificity of [UMOD](/details-gene/7369) in this cell type underscores its central role in the pathophysiology of these disorders. The profound dependence on mitochondrial function, as evidenced by the suite of highly specific respiratory chain genes, suggests that these cells are likely highly vulnerable to mitochondrial dysfunction. This could be a key mechanism in drug-induced nephrotoxicity (e.g., from cisplatin), ischemic injury during acute kidney injury (AKI), or genetic mitochondrial diseases that manifest with renal phenotypes. The high energy demand for ion transport likely leaves little metabolic reserve, making any disruption to ATP production particularly damaging. The specific expression of [ATP1B1](/details-gene/481) highlights its importance in renal physiology, and dysregulation of Na+/K+-ATPase activity is implicated in hypertension and various forms of renal salt wasting or retention. ## Potential Mechanisms and Research Directions 1. **Hypothesis: The high specificity of mitochondrial respiratory chain components renders the Loop of Henle epithelium a primary target in ischemic kidney injury.** The data suggest an extreme reliance on aerobic respiration. We hypothesize that under hypoxic conditions, this metabolic specialization becomes a critical vulnerability, leading to rapid ATP depletion, loss of ion gradients, and subsequent cell death, which is a key event in the pathogenesis of Acute Kidney Injury (AKI). * **Surprising Finding:** The most specific marker, [B2M](/details-gene/567), is part of the antigen presentation pathway, not a metabolic or transport protein. This is unexpected for a cell primarily defined by its bioenergetic and transport functions and suggests a potentially underappreciated role in immune signaling. * **Testable Question:** Using single-cell RNA sequencing on kidney tissue from an animal model of ischemia-reperfusion injury, do [kidney loop of Henle epithelial cells](/details-cell/CL1000909) show the most significant and rapid downregulation of key mitochondrial genes (e.g., [COX4I1](/details-gene/1327), [ATP5F1B](/details-gene/506)) compared to other renal epithelial cells? 2. **Hypothesis: Uromodulin ([UMOD](/details-gene/7369)) functions not only as a structural and immune protein but also as a key regulator of the metabolic phenotype in the thick ascending limb.** Given that [UMOD](/details-gene/7369) mutations lead to severe tubulointerstitial disease, we hypothesize that its function is linked to maintaining the high metabolic capacity required for ion transport, possibly by stabilizing ion transporters or influencing mitochondrial biogenesis or function. * **Surprising Finding:** Despite the cell's immense energy expenditure on ion transport, the gene profile does not highlight a uniquely specific ion transporter as the top marker. Instead, it emphasizes the generic power source (mitochondria) and a unique immunomodulatory protein ([UMOD](/details-gene/7369)), suggesting that cell identity and vulnerability may be defined more by energy supply and defense than by the transport machinery itself. * **Testable Question:** In a conditional knockout mouse model lacking [UMOD](/details-gene/7369) specifically in the loop of Henle, is there a measurable defect in maximal mitochondrial respiration or ATP production in isolated tubules, even before the onset of overt pathology?