Interleukin-17 Induced Signaling in Renal Endothelial Cells in Diabetes

Diabetes increases the risk of cardiovascular and kidney disease, in part, by increasing endothelial dysfunction through impaired NO bioavailability and is a hallmark in the progression of diabetic nephropathy. However, the precise molecular mechanisms are not well understood. Diabetes increases renal infiltration of immune cells homing the kidney and increases plasma interleukin 17 (IL17) levels in patients. In addition, IL17 has been associated to diabetes-induced end-organ damage. It’s not known whether IL17 can directly induce signaling in renal endothelial cells and its potential implication on endothelial dysfunction. We hypothesize that in a diabetic mouse model, there is an increase of kidney tissue resident immune cells that contribute to endothelial dysfunction through the release of interleukin 17. First, we isolated immune cells from kidneys of wild-type (WT) and diabetic Akita mice and performed flow cytometry analysis (FACs). FACs results showed increased resident CD8/CD4+ and TH17+ lymphocytes in Akita, compared to age-matched C57BL/6J controls (n=6; p<0.05), supporting a role of TH17 in diabetes. To test the role of IL17 on renal endothelial cells (EC), we first characterized primary kidney EC in culture. By qPCR and Western Blot, we confirmed expression of signature genes such as endothelial nitric oxide (eNOS/NOS3) (n=6), CD31 and Selectin (n=4) in cultured EC under normal glucose (NG) conditions. Additionally, vascular endothelial VE-Catherin/CD144 was localized to the plasma membrane in EC by immunofluorescence and confocal microscopy (n=3). Then, we cultured primary kidney EC in either normal glucose, NG (5mM) or high glucose, HG (20mM) media to 80-90% confluency and treated them with IL17A (50ng/ml) for 24 hours. Our results showed that IL17A significantly increased the expression of IL17 receptor (IL17RA) mRNA only when cells were grown on high glucose (NG:1.01±0.12; NG+IL17:0.83±0.08; HG: 2.11±0.71; HG+IL17A: 4.36±1.31 A.U.; p <0.05 vs control, n=6) suggesting enhanced signaling of IL17 in diabetic conditions. To study a role of IL17A on EC dysfunction we studied NOS3 expression. IL17 did not affect NOS3 in NG (n=6; p =N.S.) but increased expression in EC on HG (HG 2.03±0.15; HG+IL17A=4.6±1.1; n=6 p, 0.05 vs HG). RNAseq was performed in kidney endothelial cells which identified the expression of IL17RA, IL17RC and IL17RD receptors. We found only 94 DEG genes that were induced by IL17A in normal glucose (FDR>1 Log2 fold change, p <0.05). However, 1200 DEG were induced by IL17A in EC on HG. Bioinformatics analysis identified 1150 DEGs that were ONLY stimulated by IL17A, independently of those changed by HG alone. IL17 stimulated several genes involved in cell-cell adhesion and interactions at the vascular surface. Importantly, CAV1, and NOSTRIN which are known to inhibit NOS3 were significantly upregulated, which could be associated to compensatory increased in NOS3 and could explain our data on NOS3 protein expression. Our data support a role for IL17A on EC that only occurs under diabetic/high glucose conditions. It remains to be studied the potential implications of IL17A on renal arteriolar reactivity and its contribution to kidney damage in diabetes. This research work was supported by grant from the National Institutes of Health (NIH-R21-DK138393-01) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.