SLC25A47最初被认定为线粒体肝细胞癌（HCC）下调载体蛋白，但其生理功能和转运底物不明。我们旨在研究SLC25A47在肝代谢中的生理作用。使用二甲双胍处理肝细胞发现，二甲双胍可以转录激活Slc25a47的表达，这是AMPKα磷酸化所必需的。Slc25a47缺失小鼠具有增加的肝脂含量、甘油三酯和胆固醇水平，我们发现Slc25a47缺乏抑制了AMPKα的磷酸化，并导致升高的核SREBP脂肪酸和胆固醇生物合成活性。相反，当Slc25a47在小鼠肝脏中过度表达时，AMPKα被激活并导致抑制脂肪合成。此外，使用二乙基亚硝胺（DEN）诱导的小鼠HCC模型，我们发现Slc25a47的删除通过激活mTOR级联促进了HCC肿瘤发生和发展。采用SLC25A47的同源建模和人类代谢组数据库的虚拟筛选，我们证明NAD +是SLC25A47的内源底物，Slc25a47缺失小鼠中NAD +-依赖性SIRT3的活性下降，随后是AMPKα的失活。我们的研究结果表明，SLC25A47是肝细胞特异性的线粒体NAD +转运蛋白之一，是二甲双胍的药理靶点之一，并通过AMPKα调节脂质稳态，可能成为治疗非酒精性脂肪肝病（NAFLD）和HCC的潜在药物靶点。版权所有 © 2023美国肝脏病研究协会。

SLC25A47 was initially identified as mitochondrial hepatocellular carcinoma (HCC)-downregulated carrier protein, but its physiological functions and transport substrates are unknown. We aimed to investigate the physiological role of SLC25A47 in hepatic metabolism.Treatment of hepatocytes with metformin found that metformin can transcriptionally activate the expression of Slc25a47, which is required for AMPKα phosphorylation. Slc25a47-deficient mice had increased hepatic lipid content, triglycerides and cholesterol levels, and we found that Slc25a47-deficiency suppressed AMPKα phosphorylation and led to an increased accumulation of nuclear SREBPs with elevated fatty acid and cholesterol biosynthetic activities. Conversely, when Slc25a47 was overexpressed in mouse liver, AMPKα was activated and resulted in inhibition of lipogenesis. Moreover, using a diethylnitrosamine (DEN)-induced mouse HCC model, we found that the deletion of Slc25a47 promoted HCC tumorigenesis and development through the activated mTOR cascade. Employing homology modeling of SLC25A47 and virtual screening of the human metabolome database, we demonstrated that NAD+ was an endogenous substrate for SLC25A47 and the activity of NAD+-dependent SIRT3 declined in Slc25a47-deficient mice, followed by inactivation of AMPKα.Our findings reveal that SLC25A47, a hepatocyte-specific mitochondrial NAD+ transporter, is one of the pharmacological targets of metformin and regulates lipid homeostasis through AMPKα, and may serve as a potential drug target for treating non-alcoholic fatty liver disease (NAFLD) and HCC.Copyright © 2023 American Association for the Study of Liver Diseases.