The circFASN/miR-33a pathway participates in tacrolimus-induced dysregulation of hepatic triglyceride homeostasis.

Dyslipidemia exhibits a high incidence after liver transplantation, in which tacrolimus, a widely used immunosuppressant, plays a fundamental role. MicroRNAs and related circRNAs represent a class of noncoding RNAs that have been recognized as important regulators of genes associated with lipid metabolism. However, their transcriptional activities and functional mechanisms in tacrolimus-related dyslipidemia remain unclear. In this study, we observed that tacrolimus could induce triglyceride accumulation in hepatocytes by stimulating sterol response element-binding proteins (SREBPs) and miR-33a. Our in silico and experimental analyses identified miR-33a as a direct target of circFASN. Tacrolimus could downregulate circFASN and result in elevated miR-33a in vivo and in vitro. Overexpression of circFASN or silencing of miR-33a decreased the promoting effects of tacrolimus on triglyceride accumulation. Clinically, the incidence of dyslipidemia in liver transplant recipients with elevated serum miR-33a after liver transplantation was higher than that in patients without elevated serum miR-33a (46.3% vs. 18.8% p = 0.012, n = 73). Our results showed that the circFASN/miR-33a regulatory system plays a distinct role in tacrolimus-induced disruption of lipid homeostasis. MiR-33a is likely a risk factor for tacrolimus-related dyslipidemia, providing a potential therapeutic target to combat tacrolimus-induced dyslipidemia after liver transplantation.