Homocysteine accelerates hepatocyte autophagy by upregulation of TFEB via DNMT3b-mediated DNA hypomethylation

Autophagy plays a critical role in the physiology and pathophysiology of hepatocytes. High levels of homocysteine (Hcy) promote autophagy in hepatocytes, but the underlying mechanism is still unknown. Here, we investigated the relation between Hcy increased autophagy levels and the expression of nuclear transcription factor EB (TFEB). We demonstrate that Hcy increased autophagy levels is mediated by upregulation of TFEB. Silencing TFEB decreases the autophagy-related protein LC3BII/I and increases p62 expression levels in hepatocytes after exposure to Hcy. Moreover, the effect of Hcy on the expression of TFEB is regulated by hypomethylation of TFEB promoter catalyzed by DNA methyltransferase 3b (DNMT3b). In summary, this study shows that Hcy can activate autophagy by inhibiting DNMT3b-mediated DNA methylation and upregulating TFEB expression. These findings provide another new mechanism for Hcy-induced autophagy in hepatocytes.