LncRNA Hoxb3os protects podocytes from high glucose-induced cell injury through autophagy dependent on the Akt-mTOR signaling pathway.

Background: Diabetic nephropathy (DN) is in the first place of the causes that lead to end-stage renal disease in the world. Thus, it is urgent to develop a novel diagnostic or therapeutic strategy that could stop the progression of diabetic nephropathy.

Methods: RNA-sequencing was conducted in high glucose (HG)-treated MPC5 cells (podocytes). Cell morphology was examined under a light microscope. Upon high-glucose challenge, the effects of lncRNA Hoxb3os overexpression on MPC5 cells apoptosis, viability, autophagy and Akt-mTOR signaling were evaluated using flow cytometry, Cell Counting Kit-8, qRT-PCR, and Western blotting. TUNEL staining and ELISA were performed to confirm the establishment of DN model in db/db mice.

Results: High-glucose exposure dramatically altered lncRNA expression profile in MPC5 cells (fold change>2), including 305 upregulated lncRNAs and 451 downregulated lncRNAs. LncRNA Hoxb3os expression was significantly reduced in the HG-induced podocyte damage model, as well as in the renal tissues from db/db mice with spontaneous DN. Overexpression of Hoxb3os significantly reduced the apoptosis rate and increased the viability of MPC5 cells under HG conditions. Further study revealed that exogenous Hoxb3os increased autophagy level in HG-exposed MPC5 cells via abrogating Akt-mTOR signaling pathway and that the process was possibly implicated in the upregulation of SIRT1.

Conclusion: LncRNA Hoxb3os protected podocytes from HG-induced damage by regulating Akt-mTOR pathway and cell autophagy. Thus, lncRNA Hoxb3os appears as a potential biomarker in the diagnosis and treatment of DN in the future.