#2940 Expression and modulation of SGLT2 in human podocytes. Not all in tubule

Abstract

Abstract Background and Aims Inhibitors of the sodium-glucose cotransporter type 2 (iSGLT2) modify important non-glycemic pathways that lead to the protection of target organs. Its renoprotective pleiotropic effects in CKD, associated or not with diabetes, justifies further studies to elucidate the mechanisms of action (MoA) of these drugs. Although the co-transporter SGLT2 is mostly expressed in the proximal tubule, its location and function in other cells, that can be potential therapeutic targets for inhibitor drugs, has not been well studied. We explored the presence of SGLT2 in human podocyte cells and whether it is modified in different situations of cellular stress. Method Differentiated immortalized human podocytes were cultured under different experimental conditions for 24 or 48 h: Normoxia (Control); Normoxia + High concentration of glucose (HG); Hypoxia(1%)+2 h Reoxygenation(H) and the combination H + HG. Cells were also incubated with 0.1 uM Dihydrotestosterone (DHT). SGLT2 gene expression was determined by quantitative PCR and SGLT2 protein was detected by Western Blot (WB) and immunofluorescence (IF). Results Sglt2 gene expression was detected in human podocytes in culture, with an increase of expression after 24 h of exposure to HG. Protein expression by WB showed a trend to increase after 48h of exposure to HG and hypoxia, which was significant with co-incubation with DHT. HG plus DHT also increased the protein expression of SGLT2 under normoxic conditions. The IF measured by intensity of area did not show an increase in the protein expression of the transporter under HG incubation. However, protein expression increased under all hypoxic conditions: Control 50.05 ± 3, Hypoxia 140 ± 16.3 (p < 0.05 vs control) and HG + Hypoxia 253 ± 21.29 (p < 0.001 vs control). Conclusion Our data suggest that podocyte may be one of the therapeutic targets on which the iSGLT2 is acting. The experimental conditions described did not show differences in the expression of the transporter before the single stimulus of glucose, but they did under hypoxia and the combination Hypoxia-high glucose. In addition, co-incubation with testosterone seems to enhance the expression. Studying the MoA of iSGLT2 will open better comprehension of the kidney pathophysiology, particularly in the podocytopathies, regardless of diabetes.