Modulation by SAMe of CYP2E1-dependent Effects in Liver.

SAMe 对肝脏中 CYP2E1 依赖性效应的调节。

• 批准号: 6795965
• 负责人: ARTHUR I CEDERBAUM
• 金额: $ 33.9万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6795965
• 关键词: S adenosylmethionine; antioxidants; apoptosis; cell proliferation; cytotoxicity; ethanol; free radicals; gene expression; gene targeting; genetically modified animals; hepatotoxin; laboratory mouse; laboratory rat; liver cells; liver toxic disorder; mitogen activated protein kinase; oxidative stress; tissue /cell culture

DESCRIPTION (provided by applicant): There is interest in the role of oxidative stress and generation of reactive radical species in the mechanism(s) by which ethanol is toxic. Induction of CYP2E1 is one pathway by which ethanol generates oxidative stress. S-Adenosyl- L-Methionine (SAM) is a regulator of cellular growth, differentiation and function. Impairment of SAM synthesis plays an important role in hepatic injury induced by various agents, including alcohol. CYP2E1 levels were increased in the MAT1A knockout mouse suggesting SAM could regulate or modulate CYP2E1. The goal of this application is to study possible interactions/modulation between CYP2E1 and SAM and to investigate the effects of SAM on CYP2E1- dependent toxicity and generation of reactive oxygen species. Aim 1 will evaluate the effect of SAM, and the SAM metabolite 5-methylthioadenosine (MTA) on CYP2E 1-dependent toxicity in cultured hepatocytes from pyrazole-treated rats and HepG2 cells overexpressing CYP2E1 (E47 cells). Aim 2 will study the effect of SAM and MTA on hepatic stellate cell activation by CYP2El-derived diffusible mediators in co-cultures of primary hepatic stellate cells with pyrazole hepatocytes or E47 cells. Aim 3 will assess the effect of SAM and MTA on CYP2El-dependent activation of antioxidants genes which reflect an adaptive response to CYP2El-dependent oxidative stress. The ability of SAM or MTA to prevent activation of P38 MAP kinasc or other stress kinascs by CYP2E1 will be determined, since such actions may be important in mechanisms by which SAM or MTA prevent CYP2E1 toxicity. Aim 4 will study in-vivo effects of SAM and MTA on CYP2E1 expression, content and actions. Control rats or rats induced by pyrazole, ethanol, starvation with high levels of CYP2E 1 will be treated with SAM or MTA in-vivo and the effect on basal or induced CYP2E1 protein, activity, mRNA level on up regulation of GSH and antioxidants and on CYP2El-dependent toxicity in several in-vivo models determined. The effect of CYP2E1 induction on expression of the MAT1A and MAT2A genes or enzyme activities responsible for the synthesis of SAM will be determined. Aim 5 will evaluate the ability of SAM or MTA, in-vitro, to inhibit CYP2El-dependent generation of reactive oxygen species. It is hoped that this study utilizing hepatocyte cell culture models, in-vivo models and mechanistic studies will help to define the effects of SAM on CYP2E 1-dependent toxicity and may prove valuable in understanding the hepatoprotective actions of SAM in many models of liver injury, including alcohol-induced liver injury.

描述（由申请人提供）：人们对氧化应激和活性自由基物质的产生在乙醇有毒的机制中的作用感兴趣。 CYP2E1 的诱导是乙醇产生氧化应激的途径之一。 S-腺苷-L-甲硫氨酸 (SAM) 是细胞生长、分化和功能的调节剂。 SAM 合成受损在多种药物（包括酒精）引起的肝损伤中发挥着重要作用。 MAT1A 敲除小鼠中 CYP2E1 水平升高，表明 SAM 可以调控 CYP2E1。本申请的目的是研究 CYP2E1 和 SAM 之间可能的相互作用/调节，并研究 SAM 对 CYP2E1 依赖性毒性和活性氧生成的影响。目标 1 将评估 SAM 和 SAM 代谢物 5-甲硫腺苷 (MTA) 对经吡唑处理的大鼠培养的肝细胞和过表达 CYP2E1 的 HepG2 细胞（E47 细胞）中 CYP2E 1 依赖性毒性的影响。目标 2 将研究 SAM 和 MTA 在原代肝星状细胞与 CYP2El 衍生的扩散介质的共培养物中对肝星状细胞活化的影响 吡唑肝细胞或E47细胞。目标3将评估SAM和MTA对CYP2E1依赖性抗氧化剂基因激活的影响，这反映了对CYP2E1依赖性氧化应激的适应性反应。将确定 SAM 或 MTA 防止 CYP2E1 激活 P38 MAP 激酶或其他应激激酶的能力，因为此类作用在 SAM 或 MTA 防止 CYP2E1 毒性的机制中可能很重要。目标 4 将研究 SAM 和 MTA 对 CYP2E1 表达、内容和作用的体内影响。对照大鼠或由吡唑、乙醇、高水平CYP2E 1饥饿诱导的大鼠将在体内用SAM或MTA处理，并观察对基础或诱导的CYP2E1蛋白、活性、mRNA水平对GSH和抗氧化剂的上调以及对CYP2E1的影响。在几种体内模型中确定了CYP2E1依赖性毒性。 CYP2E1诱导对MAT1A和MAT1A表达的影响 将测定负责合成 SAM 的 MAT2A 基因或酶活性。目标5将评估SAM或MTA在体外抑制CYP2E1依赖性活性氧生成的能力。希望这项利用肝细胞培养模型、体内模型和机制研究的研究将有助于确定 SAM 对 CYP2E 1 依赖性毒性的影响，并可能对了解 SAM 在许多肝损伤模型中的保肝作用有价值。 ，包括酒精引起的肝损伤。