LncRNA HOXB3OS improves high glucose-mediated podocyte damage and progression of diabetic kidney disease through enhancing SIRT1 mRNA stability

High glucose (HG)-mediated podocyte damage can be ameliorated by lncRNA HOXB3OS, and exosomes derived from adipose-derived mesenchymal stem cells (ADSCs-Exo) can ameliorate the progression of diabetic kidney disease (DKD) dependening on RNA. To investigate the mechanism by which HOXB3OS improves podocyte injury and the effects of engineered ADSCs-Exo with a high abundance of HOXB3OS on DKD progression, MPC5 cells stimulated with HG and db/db mice were used to develop a podocyte injury model and type II DKD mouse model, respectively. HOXB3OS expression and mRNA level of SIRT1 were detected by qRT-PCR. The protein content of SIRT1 and Ythdc2 was measured through WB, IHC, and IF assays. CCK-8 assay and flow cytometry assay were used to detect cell viability and apoptosis rate of MPC5 cells. RIP assay was used to investigate the binding capacity of Ythdc2 to HOXB3OS or SIRT1 mRNA. Albuminuria, renal function and glomerular structure were observed by kits and PAS, respectively. Consequently, we found that HOXB3OS combined with Ythdc2 and inhibited the binding of Ythdc2 to SIRT1 mRNA, hence inhibiting SIRT1 mRNA degradation. SIRT1 siRNA inhibited the effect of Ythdc2 siRNA on HOXB3OS knock-down or HG-induced podocyte injury. ADSCs-Exo with a high content of HOXB3OS ameliorated HG-mediated podocyte damage and DKD progression. This suggests that engineered ADSCs-Exo with HOXB3OS can suppress Ythdc2-mediated SIRT1 mRNA degradation by disturbing the binding of Ythdc2 to SIRT1 mRNA as well as reverse SIRT1 down-regulation induced by HG, thereby ameliorating podocyte injury and DKD progression.