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）：对氧化应激和反应性自由基物质在乙醇毒性机制中的作用感兴趣。CYP 2 E1的诱导是乙醇产生氧化应激的一种途径。S-腺苷-L-甲硫氨酸（SAM）是细胞生长、分化和功能的调节剂。SAM合成受损在包括酒精在内的各种药物诱导的肝损伤中起重要作用。在MAT 1A基因敲除小鼠中，CYP 2 E1水平升高，表明SAM可以调节或调节CYP 2 E1。本申请的目的是研究CYP 2 E1和SAM之间可能的相互作用/调节，并研究SAM对CYP 2 E1依赖性毒性和活性氧产生的影响。目的1评价SAM及其代谢产物5-甲硫基腺苷（MTA）对吡唑处理的大鼠肝细胞和过表达CYP 2 E1的HepG 2细胞（E47细胞）的CYP 2 E1依赖性毒性的影响。目的2：研究SAM和MTA对原代肝星状细胞与CYP 2 E1共培养物中CYP 2 E1源性扩散介质激活肝星状细胞的影响。 吡唑肝细胞或E47细胞。目的3将评估SAM和MTA对CYP 2 E1依赖的抗氧化剂基因的激活的影响，所述抗氧化剂基因反映了对CYP 2 E1依赖的氧化应激的适应性反应。将测定SAM或MTA防止P38 MAP激酶或其他应激激酶被CYP 2 E1激活的能力，因为这些作用在SAM或MTA防止CYP 2 E1毒性的机制中可能是重要的。目的4研究SAM和MTA对CYP 2 E1表达、含量和作用的影响。将用SAM或MTA在体内处理对照大鼠或由吡唑、乙醇、饥饿诱导的具有高水平CYP 2 E1的大鼠，并在几种体内模型中测定对基础或诱导的CYP 2 E1蛋白、活性、GSH和抗氧化剂上调的mRNA水平以及对CYP 2 E1依赖性毒性的影响。CYP 2 E1诱导对MAT 1A和 将确定负责SAM合成的MAT 2A基因或酶活性。目的5将评价SAM或MTA在体外抑制CYP 2 E1依赖性活性氧产生的能力。希望本研究利用肝细胞培养模型，体内模型和机制研究将有助于确定SAM对CYP 2 E 1依赖性毒性的影响，并可能在了解SAM在许多肝损伤模型（包括酒精诱导的肝损伤）中的保肝作用方面具有价值。