Renal glycosphingolipid Gb3Cer/CD77 expression in rat models of type 1 and type 2 diabetes

Background: The kidney expresses relatively high levels of glycosphingolipid globotriaosylceramide (Gb3Cer or CD77) compared with other organs. Glycosphingolipids are found in membrane lipid rafts where they influence function of receptors and transporters embedded in these domains. In addition, CD77 serves se E. coli verotoxin receptor. Renal glucose reabsorption in diabetes mellitus (DM) is altered, and glycosuria provides a favorable environment for bacteria to reside and grow in the urinary tract, often leading to urinary tract infection. Therefore, the aim of our study was to determine CD77 expression on renal endothelial and non-endothelial cells, in rat models of DM type 1 (T1DM) and type 2 (T2DM). Methods: Diabetes was induced with streptozotocin (55 mg kg−1 for T1DM and 35 mg kg−1 for T2DM) injection to rats which were fed with normal pellet diet (T1DM) or high-fat diet (T2DM). The endothelial marker CD34 and glycosphingolipid CD77 were determined in renal cell suspensions by flow cytometry. Results: Rats of T2DM model showed twice lower proportion of renal CD77 positive non-endothelial cells in comparison to corresponding control rats (P = 0.016). Conclusions: Our study showed that the CD77 positive non-endothelial renal cells could specifically mirror diabetic nephropathy. The reason of increased susceptibility to bacteria other than E. coli in diabetic patients could lay in changed membrane glycosphingolipid composition.