Introduction and Objective: Diabetic Kidney Disease (DKD) occurs commonly in people with diabetes and often presents with albuminuria resulting from glomerular filtration barrier injury. The glycocalyx, an extracellular matrix (ECM) produced by endothelial cells, plays a critical role in regulating glomerular filtration.Methods: To test if diabetes induces ECM changes, we examined the abundance of glomerular glycocalyx in a mouse model of DKD (BTBR Lepob; OB) and in nondiabetic (ND) mice. Glycocalyx abundance was assessed using wheat germ agglutinin (WGA) staining, which selectively marks glycocalyx, quantified through immunohistochemistry and flow cytometry. Single-cell RNA sequencing (scRNA-seq) was used to examine the expression of genes involved in ECM remodeling.Results: Diabetes significantly reduced glomerular glycocalyx in OB vs ND mice. Glomerular WGA accumulation was 27.1±2.7% (mean±SEM) of glomerular area in ND compared to 19.6±2.7% in OB mice (p=4.5×10-2; n=20-21). Flow cytometric analysis of cortical endothelial cells similarly showed diabetes decreased endothelial cell WGA binding by 19.8±4.7% compared to ND mice (p=4.2×10-3; n=17-21), indicating a reduction in the glycocalyx in DKD. Gene Set Enrichment analysis of scRNA-seq data from adults with DKD from the Kidney Precision Medicine Project and our data from OB vs ND mice indicated ECM remodeling is a key pathway altered in human and mouse endothelial cells in DKD. Consistent with an increased turnover of the ECM, expression of enzymes such as Adamts6, a protease that cleaves ECM components, was increased in the scRNA-seq dataset (1.6-fold, p=2.1×10-6) and in isolated endothelial cells from diabetic mice (2.5±0.5-fold, p=2.9×10-2; n=4).Conclusion: ECM remodeling may be induced by increased expression of ECM-degrading enzymes in diabetes, contributing to the glomerular filtration barrier breakdown seen in DKD.
A.E. Reed: None. F. Kramer: None. J. Cervantes: None. C. Limonte: None. J.E. Kanter: None.
American Diabetes Association (11-22-IBSPM-09); National Institutes of Health (R01DK121756)
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