TFAP2A orchestrates gene regulatory networks and tubular architecture in kidney outer medullary collecting ducts
Janna Leiz, … , Christian Hinze, Kai M. Schmidt-Ott
Janna Leiz, … , Christian Hinze, Kai M. Schmidt-Ott
Published August 28, 2025
Citation Information: JCI Insight. 2025;10(19):e192361. https://doi.org/10.1172/jci.insight.192361.
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Research Article Cell biology Nephrology

TFAP2A orchestrates gene regulatory networks and tubular architecture in kidney outer medullary collecting ducts

Abstract

Mutations in the transcription factor TFAP2A are linked to congenital anomalies of the kidney and urinary tract in humans. While Tfap2a knockout (KO) in mouse collecting ducts leads to tubular epithelial abnormalities, its precise molecular functions in kidney tubules remain unclear. To investigate Tfap2a-dependent gene regulatory networks in the mouse kidney collecting ducts, we employed conditional KO (Hoxb7-Cre; Tfap2afl/fl) models combined with transcriptomics. Histomorphological and physiological assessments of Tfap2a-KO mice revealed progressive postnatal dilation of the outer medullary collecting ducts. Integrating bulk and single-nucleus RNA sequencing with in silico motif mapping in ATAC-seq datasets demonstrated that Tfap2a is highly expressed and active in normal collecting duct principal cells. Comparative transcriptomics between 3-month-old Tfap2a-KO and control mice identified dysregulated genes associated with cell adhesion and WNT signaling, including Alcam and Wnt9b. These changes were confirmed by in situ hybridization. Our findings reveal that Tfap2a regulates medullary collecting duct diameter by orchestrating a transcriptional network involving Wnt9b and Alcam, providing insights into its role in kidney structural integrity.

Authors

Janna Leiz, Karen I. López-Cayuqueo, Shuang Cao, Louisa M.S. Gerhardt, Christian Hinze, Kai M. Schmidt-Ott

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Figure 5

Hoxb7Cre+;Tfap2afl/fl mice show no overt changes in cell type abundance compared to controls, based on snRNA-seq and immunofluorescence.

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Hoxb7Cre+;Tfap2afl/fl mice show no overt changes in cell type abundance...
(A) snRNA-seq was performed on kidneys from 3-month-old male control and Hoxb7Cre+;Tfap2afl/fl mice (n = 2 per group). (B) Uniform manifold approximation and projection (UMAP) of snRNA-seq data (26,105 nuclei) from both genotypes. Nuclei were annotated using known marker genes as podocytes (Podo), proximal tubule (PT), thin limb (tL), thick ascending limb (TAL), distal convoluted tubule (DCT), connecting tubule (CNT), collecting duct principal cells (CD-PCs), collecting duct intercalated cells (CD-ICs), deep medullary epithelium of pelvis (DMEP), endothelial cells (ECs), interstitial cells (IntCs), and immune cells (ImCs). Damaged nuclei were excluded. (C) Dot plot showing expression of cell-type-specific markers in broad cell types. Dot color reflects scaled average expression; size indicates the percentage of cells expressing the gene. (D) UMAP of subclustered CD-PC nuclei, annotated into cortical (CCD), outer medullary (OMCD), and inner medullary (IMCD1–3) PCs. (E) Dot plot showing marker gene expression for CD-PC subclusters. (F) Cell type proportions across broad populations in both genotypes (mean ± SD; n = 2 per group). (G) Distribution of CD-PC subclusters in control and mutant mice (mean ± SD; n = 2 per group). (H) Left: Immunofluorescent staining for PC marker aquaporin-2 (AQP2, cyan) and intercalated cell marker V-ATPase B1/2 (yellow) in OMCDs from 11-week-old control and mutant mice. Scale bar: 100 μm. Right: Quantification of PC and IC percentages in OMCDs (n ≥ 4 mice per group; mean ± SD). No significant differences were observed (2-tailed t test, equal variances not assumed).