ETHNIC VARIABILITY IN AN ETHANOL INDUCIBLE P450 ENZYME

酗酒的发生率在美洲原住民和 高加索人的墨西哥裔美国人。原因可能是社会学的， 心理的、生化的或这些因素的组合。在……里面 除了酗酒的发生率更高之外，还有一个增加的 这两个人群中酒精性肝病的易感性 这在一定程度上可能与酒精的代谢有关。P4502E1为 已知可将包括乙醇在内的几种化合物代谢成对肝脏有毒性的化合物 代谢物。此外，长期接触酒精会导致 在这种特殊的P450酶的表达中。这一增长 表达可能在隐匿性肝病的发生发展中起作用 从酒精和由这种酶代谢的其他肝毒素中提取。一个焦点 这项建议的目的是确定P4502E1是否在 某些人对与酒精有关的肝损伤的易感性。 这将通过筛选来自三个不同种族的淋巴细胞来进行调查。 人口，土著美国人，墨西哥裔美国人和高加索人 酒精性和非酒精性，对于表达的差异 酵素。为了确定酶的表达，将分离淋巴细胞 从酗酒和非酗酒的受试者身上采集的全血 这三个亚群都是。P4502E1将通过免疫印迹进行监测 用单细胞凝胶电泳法分析淋巴细胞微粒体 制备抗人肝脏P4502E1的特异性抗体。检测到一个 这种酶的升高可以作为预测化学或 酒精引起的肝毒性可能会导致。这项提案的重点是 以确定不同种族人群是否可以使用这种酶 作为酒精依赖型肝病的生化标志物 被认为是高危人群的亚群。鉴定 还提出了在CYP2E1调控区域的特定RFLP的建议 这将与表型表达、种族和 酗酒。淋巴细胞中P4502E1的进一步鉴定将 包括检查酒精是否会导致P4502E1mRNA的增加 随后酶的增加。这将通过以下方式实现 酒精性和非酒精性组织中mRNA的Northern印迹分析 受试者和结果可能提供一种乙醇增加的机制 淋巴细胞中的P4502E1。来自我们实验室的初步证据 提示淋巴细胞酶表现出一个相对分子质量(MW) 与肝脏的P450不同。因此， 还将检测淋巴细胞蛋白，并与肝脏P4502E1进行比较 为了评估改变的结构是否改变了活动 酶的活性。P4502E1在卵巢癌组织中的表达及调控 淋巴细胞与肝脏中的淋巴细胞平行将在 氯唑沙宗作为肝脏P4502E1标志物的临床研究 功能。如果这种酶可以被酒精诱导，淋巴细胞和它的 调节和表达反映了肝脏的调节和表达，人类血液可能 一个易于获得的组织，用于表型和研究肝脏的调节 P4502E1在人类中的表达。

The incidence of alcoholism is much higher in Native Americans and Mexican Americans that in Caucasians. The reasons may be sociological, psychological, biochemical, or a combination of these factors. In addition to a higher incidence of alcoholism, there is also an increased susceptibility of alcohol related liver disease in these two populations which may, in part, be related to metabolism of alcohol. P4502E1 is known to metabolize several compounds including ethanol to hepatotoxic metabolites. Moreover, chronic exposure to alcohol causes an increase in the expression of this particular P450 enzyme. This increase in expression may play a role in the development of occult liver disease from alcohol and other hepatotoxins metabolized by this enzyme. A focus of this proposal is to determine whether P4502E1 plays a role in the susceptibility of certain individuals to alcohol-related liver injury. this will be investigated by screening lymphocytes from 3 separate ethnic populations, Native Americans, Mexican Americans and Caucasians both alcoholic and non-alcoholic, for differences in the expression of the enzyme. To determine enzyme expression, lymphocytes will be isolated from whole blood collected from alcoholic and nonalcoholic subjects from all three subpopulations. P4502E1 will be monitored by immunoblot analysis of microsomes isolated from the lymphocytes using a mono- specific antibody prepared to human liver P4502E1. Detection of an elevation in this enzyme may serve as a predictor that chemical or alcohol-induced hepatotoxicity may result. This proposal focuses on different ethnic populations to determine whether this enzyme can be used as a biochemical marker of alcohol-dependent liver disease in subpopulations which are considered to be at high risk. Identification of specific RFLPs in the regulatory region of CYP2E1 is also proposed which will be correlated with phenotypic expression, ethnicity and alcoholism. Further characterization of P4502E1 in lymphocytes will involve examining whether ethanol causes an increase in P4502E1 mRNA with a subsequent increase in the enzyme. This will be accomplished by Northern blot analysis of mRNA isolated from alcoholic and non-alcoholic subjects and results may provide a mechanism in which ethanol increases P4502E1 in lymphocytes. Preliminary evidence from our laboratory suggests that the lymphocyte enzyme exhibits a molecular weight (MW) difference from that of the liver P450. Thus, the structure of the lymphocyte protein will also be examined and compared to liver P4502E1 in order to assess whether the altered structure modifies the activity of the enzyme. Whether the expression and regulation of P4502E1 in lymphocytes parallels that which is in liver will be determined in a clinical study using the drug chlorozoxazone as a marker of liver P4502E1 function. If the enzyme is inducible by alcohol in lymphocytes and its regulation and expression mirrors that of the liver, human blood may be a readily accessible tissue to phenotype and study regulation of liver P4502E1 in humans.