Life Science Division, AU-KBC Research Centre, MIT Campus of Anna University, Chromepet, Chennai-600044, India.
Life Sci. 2013 Mar 14;92(6-7):325-36. doi: 10.1016/j.lfs.2012.12.014. Epub 2013 Jan 24.
Ethanol metabolism leads to the formation of acetaldehyde and malondialdehyde. Acetaldehyde and malondialdehyde can together form malondialdehyde-acetaldehyde (MAA) adducts. The role of alcohol dehydrogenase (ADH) and cytochrome P4502E1 (CYP2E1) in the formation of MAA-adducts in liver cells has been investigated.
Chronic ethanol treated VL-17A cells over-expressing ADH and CYP2E1 were pretreated with the specific CYP2E1 inhibitor - diallyl sulfide or ADH inhibitor - pyrazole or ADH and CYP2E1 inhibitor - 4-methyl pyrazole. Malondialdehyde, acetaldehyde or MAA-adduct formation was measured along with assays for viability, oxidative stress and apoptosis.
Inhibition of CYP2E1 with 10 μM diallyl sulfide or ADH with 2mM pyrazole or ADH and CYP2E1 with 5mM 4-methyl pyrazole led to decreased oxidative stress and toxicity in chronic ethanol (100 mM) treated VL-17A cells. In vitro incubation of VL-17A cell lysates with acetaldehyde and malondialdehyde generated through ethanol led to increased acetaldehyde (AA)-, malondialdehyde (MDA)-, and MAA-adduct formation. Specific inhibition of CYP2E1 or ADH and the combined inhibition of ADH and CYP2E1 greatly decreased the formation of the protein aldehyde adducts. Specific inhibition of CYP2E1 led to the greatest decrease in oxidative stress, toxicity and protein aldehyde adduct formation, implicating that CYP2E1 accelerates the formation of protein aldehyde adducts which can be an important mechanism for alcohol mediated liver injury.
CYP2E1-mediated metabolism of ethanol leads to increased AA-, MDA-, and MAA-adduct formation in liver cells which may aggravate liver injury.
乙醇代谢会导致乙醛和丙二醛的形成。乙醛和丙二醛可以共同形成丙二醛-乙醛（MAA）加合物。已经研究了在肝细胞中形成 MAA 加合物的醇脱氢酶（ADH）和细胞色素 P4502E1（CYP2E1）的作用。
用特异性 CYP2E1 抑制剂 - 二烯丙基硫醚或 ADH 抑制剂 - 吡唑或 ADH 和 CYP2E1 抑制剂 - 4-甲基吡唑预处理过表达 ADH 和 CYP2E1 的慢性乙醇处理的 VL-17A 细胞。同时测定丙二醛、乙醛或 MAA 加合物的形成以及活力、氧化应激和细胞凋亡的测定。
用 10 μM 二烯丙基硫醚抑制 CYP2E1，用 2mM 吡唑抑制 ADH，或用 5mM 4-甲基吡唑抑制 ADH 和 CYP2E1，可导致慢性乙醇（100mM）处理的 VL-17A 细胞的氧化应激和毒性降低。体外将 VL-17A 细胞裂解物与通过乙醇产生的乙醛和丙二醛孵育，会导致乙醛（AA）-、丙二醛（MDA）-和 MAA 加合物形成增加。特异性抑制 CYP2E1 或 ADH 以及 ADH 和 CYP2E1 的联合抑制大大降低了蛋白质醛加合物的形成。特异性抑制 CYP2E1 导致氧化应激、毒性和蛋白质醛加合物形成的最大减少，这表明 CYP2E1 加速了蛋白质醛加合物的形成，这可能是酒精介导的肝损伤的重要机制。
CYP2E1 介导的乙醇代谢会导致肝细胞中 AA-、MDA-和 MAA 加合物形成增加，从而可能加重肝损伤。
