REGULATION OF XENOBIOTIC-METABOLIZING CYP3A

描述：（改编自研究者摘要）细胞色素P450 3A （CYP3A）水平是黄曲霉毒素和对乙酰氨基酚的重要决定因素 毒性以及许多治疗剂的吸收和消除。CYP3A 据报道，一些CYP3A底物可稳定蛋白质。的PI 报道了几种结构和功能不同的药物， 未知CYP3A底物改变原代培养物中CYP3A蛋白的稳定性 大鼠肝细胞。CYP3A稳定性的变化与以下因素的影响一致 这些试剂对磷脂酶C或D（分别为PLC或PLD）起作用。研究 微粒体表明PLD代谢产物磷脂酸（PA）是 对确定CYP3A稳定性很重要。我们建议检验这一假设 CYP3A蛋白稳定性依赖于微粒体PA水平， 进一步阐明磷脂酶和其他 调节PA水平的酶有助于CYP3A蛋白的稳定性。的 具体目标是：1）进一步确立PLD和PLC在 CYP3A蛋白稳定性的调节。2)以确定是否代理人改变 原代肝细胞培养物中的CYP3A稳定性也在体外发挥作用 孵化。3.）第三章为了确定具有不同脂肪酸部分的PA类似物是否 对微粒体样品中CYP3A蛋白稳定性有明显影响。4)到 确定调节大鼠CYP3A稳定性的药物是否以类似方式起作用 在人原代培养的肝细胞和微粒体中。这些研究将 提供可用于预测药物相互作用的信息， 了解参与的潜在分子机制， CYP3A的翻译后调节，并将测试一个新的假设 关于磷脂酶活性的相互作用， 药物代谢酶

DESCRIPTION: (Adapted from the Investigator's Abstract) Cytochrome P450 3A (CYP3A) levels are important determinants of aflatoxin and acetaminophen toxicity and the uptake and elimination of numerous therapeutic agents. CYP3A protein has been reported to be stabilized by some CYP3A substrates. The PI reported that several structurally and functionally distinct agents that are not known CYP3A substrates alter CYP3A protein stability in primary cultured rat hepatocytes. The changes in CYP3A stability are consistent with effects of these agents on phospholipase C or D (PLC or PLD, respectively). Studies in microsomes have indicated that the PLD metabolite, phosphatidic acid (PA), is important in determining CYP3A stability. We propose to test this hypothesis that CYP3A protein stability is dependent upon microsomal PA levels and to further elucidate the molecular mechanism by which phospholipases and other enzymes that regulate PA levels contribute to CYP3A protein stability. The specific aims are: 1) To further establish the role of PLD and PLC in the regulation of CYP3A protein stability. 2) To determine if agents that alter CYP3A stability in primary cultured hepatocytes also function in in vitro incubations. 3.) To determine if PA analogs with different fatty acid moieties have distinct effects on CYP3A protein stability in microsomal samples. 4) To determine whether agents that regulate rat CYP3A stability act in a like manner in human primary cultured hepatocytes and microsomes. These studies will provide information that can be used to predict drug interactions by providing an understanding of the underlying molecular mechanisms involved in the post-translational regulation of CYP3A, and will test a new hypothesis regarding the interactions of phospholipase activities and a key drug-metabolizing enzyme.