Single-cell analysis of endothelial cell injury in IgA nephropathy
Description
Abstract Background The molecular mechanisms underlying kidney damage in IgA nephropathy (IgAN) are not fully understood. The development of single-cell RNA sequencing (scRNA-seq) technology provides a novel strategy for investigating IgAN pathogenesis. Methods We obtained scRNA-seq data from the Gene Expression Omnibus database and performed bioinformatics analysis, including differentially expressed gene enrichment, AUCell, and high-dimensional weighted gene co-expression network analysis (hdWGCNA). The findings of these analyses were verified in human renal glomerular endothelial cells (HRGECs). The expression of vascular endothelial cell cadherin (VE-cad) was detected by western blotting, and Rac1-GTP expression was monitored by pull-down assays. Results scRNA-seq data revealed significantly differentially expressed genes between IgAN and control kidney tissues, enriched in the adhesion junction pathway. AUCell analysis showed that adhesion molecules and mitogen-activated protein kinase signaling pathway components were highly expressed in renal endothelial cells. Genes differentially expressed in renal endothelial cells were also found to be enriched in the focal adhesion pathway following Kyoto Encyclopedia of Genes and Genomes analysis, and cadherin binding was identified by gene ontogeny analysis. In addition, hdWGCNA revealed that interleukin (IL)-6, Rac1, and cadherin were associated with renal endothelial cells. IL-6/IL-6 receptor stimulation of HRGECs significantly decreased VE-cad expression; Rac1 inhibition significantly decreased Rac1-GTP and increased VE-cad expression. Conclusions To the best of our knowledge, this is the first study to show the involvement of renal endothelial cells in IgAN using scRNA-seq. Cell experiments confirmed that IL-6 downregulates the expression of VE-cad in glomerular endothelial cells through Rac1, suggesting that the renal endothelial system plays an important role in the pathogenesis of IgAN. These results provide a new perspective for understanding the pathogenesis of IgAN and identifying new therapeutic targets.