Abstract:

Objective: To dissect the cellular and molecular features of renal fibrosis and identify key regulatory signaling axes via single-cell transcriptome sequencing (scRNA-seq), so as to provide new evidence for mechanistic investigation and targeted intervention of renal fibrosis. Methods: Unilateral Ureteral Obstruction (UUO) rat models of renal fibrosis were established. scRNA-seq was performed for cell clustering, marker gene screening, pseudotime trajectory and cell-cell communication analysis of renal tissues to screen key molecules and characterize cell interaction patterns. HE, Masson and immunofluorescence double staining were used for histological validation. Results: A total of 12 major cell types were identified. PTCs were suggested as core functional cells in renal fibrosis and could be divided into 5 subsets with distinct functional heterogeneity. Pseudotime analysis showed that inflammatory transcriptional signatures gradually increased during PTC injury progression. Cell communication analysis indicated that the Col4a1-Sdc4 axis might mediate abnormal crosstalk among PTCs, endothelial cells and fibroblasts. Immunofluorescence confirmed COL4A1 and SDC4 in fibrotic kidneys, further supporting the involvement of this axis in renal fibrosis. Conclusion: This study reveals the functional heterogeneity of PTCs in renal fibrosis, and suggests that multi-cell abnormal crosstalk mediated by the Col4a1-Sdc4 axis may serve as an important molecular mechanism underlying renal fibrosis.

Key words: single-cell transcriptome sequencing, renal fibrosis, proximal tubular cells, cell heterogeneity, Col4a1-Sdc4