Yiqi Huoxue Yangyin Decoction attenuates diabetic nephropathy in db/db mice by modulating METTL3-mediated m6A methylation of mTOR to restore podocyte autophagy

Background Diabetic nephropathy (DN) is a major complication of diabetes with limited therapeutic options. Yiqi Huoxue Yangyin Decoction (YHY), a traditional Chinese medicine formula designed to treat the TCM syndrome of “Qi and Yin deficiency with blood stasis” often observed in DN, has shown clinical potential. However, its precise mechanism of action, particularly concerning the regulation of podocyte autophagy, remains unclear. Methods The chemical profile of YHY was characterized using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The therapeutic effects and mechanisms were evaluated in a db/db mouse model of DN and in high glucose-stimulated MPC-5 podocytes. Key assessments included renal function, podocyte injury markers, autophagy flux, and the activity of the METTL3-m6A-mTOR pathway. Results UPLC-MS/MS analysis successfully identified multiple chemical metabolites in YHY, providing a comprehensive phytochemical profile of the formula. Treatment with YHY significantly ameliorated renal dysfunction and attenuated podocyte injury in db/db mice. Both in vivo and in vitro models exhibited impaired autophagy and hyperactivated mTOR signaling under diabetic conditions. Crucially, YHY treatment inhibited METTL3 expression and m6A methylation levels, leading to decreased mTOR mRNA stability and protein expression, which subsequently restored autophagic activity. Conclusion YHY, a traditional Chinese medicine formula with defined chemical metabolites, ameliorates podocyte damage in DN by activating autophagy via the METTL3-m6A-mTOR signaling pathway. This study provides novel insights into the epigenetic regulation of DN and underscores the potential of YHY as a therapeutic agent for this condition.