Paeonol ameliorates diabetic nephropathy by promoting TFEB-mediated lysosome biogenesis and lipophagy

Diabetic nephropathy (DN) is a significant clinical and public health burden worldwide whose magnitude underscores the urgent need for more effective treatment options. Excessive lipid accumulation in renal tubular cells leads to their injury and dysfunction, thereby contributing to DN progression, suggesting that the alleviation of renal tubular lipid accumulation is a potential strategy for treating DN.

The effects of paeonol (PAE), a natural phenolic compound, on renal tubular lipid accumulation were evaluated using a glucolipotoxicity-treated HK-2 cell line and C57BL/6 J mice treated with streptozotocin (STZ) injection combined with a high-fat diet (HFD). Autophagic flux and lipophagy were assessed through immunofluorescence, adenoviral mRFP-GFP-LC3 transfection, and western blotting. Small interfering RNA (siRNA) was used for in vitro experiments to silence Tfeb in HK-2 cells, while a Cre-loxP system was employed to induce Tfeb knockout specifically in renal tubules in vivo, to validate the therapeutic target of PAE. RNA sequencing, pulldown assays, surface plasmon resonance (SPR), and molecular docking were utilized to further explore the specific molecular mechanisms involved.

We found that PAE dose-dependently alleviated renal tubular lipid accumulation in glucolipotoxicity-treated HK-2 cells and the DN mouse model. Mechanistically, PAE directly binds to RHEB, functioning as an mTOR suppressor, thereby activating TFEB to promote lysosome biogenesis and lipophagy, subsequently alleviating renal tubular lipid accumulation and DN progression.

Per our findings, PAE holds promise as a therapeutic agent for DN, with the unique mechanism of activating renal TFEB-mediated lipophagy.