REGULATION OF XENOBIOTIC-METABOLIZING CYP3A

描述：(改编自《调查者摘要》)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 毒性以及对多种治疗剂的吸收和消除。细胞色素P3A 据报道，一些细胞色素P3A底物可以稳定蛋白质。《少年派》 据报道，几种结构和功能截然不同的制剂 未知的细胞色素P3A底物对原代培养的细胞色素P3A蛋白稳定性的影响 大鼠肝细胞。细胞色素P3A稳定性的变化与药物的作用一致 这些药物作用于磷脂酶C或D(分别为PLC或PLD)。研究项目： 微粒子表明，PLD的代谢物磷脂酸(PA)是 对确定细胞色素P3A的稳定性很重要。我们建议检验这一假设 CYP3A蛋白的稳定性依赖于微粒体PA水平和 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。这个 具体目标是：1)进一步确立可编程逻辑器件和PLC在 细胞色素P3A蛋白稳定性的调节。2)确定代理是否更改 原代培养肝细胞中细胞色素P3A的稳定性也在体外发挥作用 孵化。3.)确定PA是否与不同的脂肪酸部分类似 对微粒体样品中的CYP3A蛋白稳定性有明显的影响。4)至 确定调节大鼠细胞色素P3A稳定性的药物是否以类似的方式起作用 在人类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，方法是 对涉及到的潜在分子机制的理解 翻译后对CYP3A的调节，并将检验一个新的假说 关于磷脂酶活性的相互作用和一个关键 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.