Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy.
FASEB J. 2018 Jun;32(6):3278-3288. doi: 10.1096/fj.201701124R. Epub 2018 Jan 18.
Alcohol acts through numerous pathways leading to alcoholic liver disease (ALD). Cytochrome P450 (CYP2E1), an ethanol-inducible enzyme, metabolizes ethanol-producing toxic reactive oxygen species (ROS) and is regulated at the posttranslational level. Small ubiquitin-like modifier (SUMO)ylation is a posttranslational modification that involves the addition of SUMOs, which modulate protein stability, activity, and localization. We demonstrated that ubiquitin-conjugation enzyme 9, the SUMO-conjugating enzyme, is induced in the livers of an intragastric ethanol mouse model. Our aim is to examine whether SUMOylation could regulate ethanol-induced CYP2E1 expression in ALD and to elucidate the molecular mechanism(s). CYP2E1 and UBC9 expression in vitro and in vivo was detected by real-time PCR and immunoblotting/immunostaining. SUMOylation was assayed by mass spectrometry and coimmunoprecipitation. Ubc9 expression was induced in ethanol-fed mouse livers, and silencing inhibited ethanol-mediated CYP2E1 microsomal retention and enzymatic activity. CYP2E1 SUMOylation was found to be induced by ethanol in vitro and in vivo. Ubc9 silencing prevents ethanol-induced lipid accumulation and ROS production. UBC9 was highly expressed in human ALD livers. Finally, we found that lysine 410 is a key SUMOylated residue contributing to CYP2E1 protein stability and activity preventing CYP2E1 SUMOylation. Ethanol-mediated up-regulation of CYP2E1 via SUMOylation enhancing its protein stability and activity and may have important implications in ALD.-Tomasi, M. L., Ramani, K., Ryoo, M., Cossu, C., Floris, A., Murray, B. J., Iglesias-Ara, A., Spissu, Y., Mavila, N. SUMOylation regulates cytochrome P450 2E1 expression and activity in alcoholic liver disease.
酒精通过多种途径导致酒精性肝病 (ALD)。细胞色素 P450 (CYP2E1) 是一种乙醇诱导的酶，代谢乙醇产生的有毒活性氧 (ROS)，并在翻译后水平上受到调节。小泛素样修饰物 (SUMO) 化是一种翻译后修饰，涉及 SUMO 的添加，SUMO 调节蛋白质稳定性、活性和定位。我们证明，在胃内乙醇小鼠模型的肝脏中，泛素连接酶 9，即 SUMO 连接酶，被诱导。我们的目的是研究 SUMO 化是否可以调节 ALD 中乙醇诱导的 CYP2E1 表达，并阐明分子机制。通过实时 PCR 和免疫印迹/免疫染色检测 CYP2E1 和 UBC9 在体外和体内的表达。通过质谱和共免疫沉淀测定 SUMOylation。在乙醇喂养的小鼠肝脏中诱导 Ubc9 表达，沉默抑制乙醇介导的 CYP2E1 微粒体保留和酶活性。发现 CYP2E1 在体外和体内被乙醇诱导 SUMO 化。Ubc9 沉默可防止乙醇诱导的脂质积累和 ROS 产生。UBC9 在人类 ALD 肝脏中高表达。最后，我们发现赖氨酸 410 是一个关键的 SUMO 化残基，有助于 CYP2E1 蛋白质稳定性和活性，防止 CYP2E1 SUMO 化。乙醇通过 SUMO 化上调 CYP2E1，增强其蛋白质稳定性和活性，这可能对 ALD 具有重要意义。
