Virus-Receptor Interaction and CYP3A Expression

描述（由申请人提供）：在感染和炎症期间，由于肝脏细胞色素P450 （CYP）含量减少，肝脏代谢药物的能力受损，这可能使临床上重要的药物无效或有毒。细胞因子和趋化因子作为血液介质对肝脏的影响。然而，细胞因子改变CYP的确切机制尚不清楚。感染后，病毒从与细胞表面的受体结合起就接管细胞机制进行自我复制和存活。整合素是在所有有核细胞上表达的异二聚体蛋白，是各种病原体的进入位点。它们还在细胞内启动信号来调节基因转录、细胞增殖和存活。对大鼠和人肝细胞原代培养中CYP表达的研究表明，整合素影响CYP的表达和功能。本研究的目的是利用重组腺病毒载体作为原型病原体，研究病毒引起的药物代谢长期改变的机制。正在验证的假设是，病毒蛋白与整合素受体的相互作用是导致肝脏CYP基因表达和功能改变的原因。衣壳蛋白的作用将通过以下两种方法来评估：用去除所有病毒基因的“去内脏”病毒、不与整合素受体相互作用的聚乙二醇化病毒、紫外线灭活病毒或野生型病毒治疗大鼠。我们还将确定这些药物对CYP的改变是否通过体内和大鼠肝细胞无巨噬细胞原代培养中的转录、转录后或翻译后机制实现，以排除细胞因子的影响。这一假设尚未得到验证，可能会对目前关于CYP基因表达调控的思想产生重大影响。这是非常重要的，因为病毒感染病例在普通人群中不断升级，病毒被用作基因治疗和疫苗接种方案的药物。这些研究的结果可能会导致新的抗病毒药物的开发，鉴定遗传标记以筛选患者潜在的药物代谢异常，并可能找到减轻病毒感染期间药物诱导毒性的方法，以及设计更安全的重靶向病毒用于治疗应用。

DESCRIPTION (provided by applicant): During infection and inflammation, the capacity of the liver to metabolize drugs is impaired due to a reduction in hepatic content of cytochrome P450 (CYP), which can render clinically important medications ineffective or toxic. Cytokines and chemokines contribute as blood borne mediators of this effect on the liver. However, the exact mechanism by which cytokines alter CYP is unknown. Upon infection, viruses take over cellular machinery for self-replication and survival from the time the virus binds to receptors on the cell surface. Integrins, heterodimeric proteins expressed on all nucleated cells, serve as a site of entry for various pathogens. They also initiate signals inside the cell to regulate gene transcription, cell proliferation and survival. Studies of CYP expression in primary cultures of rat and human hepatocytes suggest that integrins influence CYP expression and function. The objective of this study is to investigate mechanisms of long-term virus-induced alterations in drug metabolism, using recombinant adenoviral vectors as prototype pathogens. The hypothesis being tested is that interaction of viral proteins with integrin receptors is responsible for changes of hepatic CYP gene expression and function. Capsid protein effects will be assessed by treating rats with either a "gutted" virus with all viral genes deleted, PEGylated virus which does not interact with integrin receptors, UV inactivated or wild type virus. We will also determine if changes in CYP by these agents is achieved by transcriptional, posttranscriptiontional or postranslational mechanisms in vivo and in macrophage free primary cultures of rat hepatocytes to rule out cytokine effects. This hypothesis has not been tested and could have significant impact on current thought on regulation of CYP gene expression. This is of vast importance as cases of viral infection escalate in the general population and viruses are used as medicinal agents for gene therapy and vaccination protocols. Results from these studies could lead to the development of new anti-viral agents, identification of genetic markers to screen patients for potential aberrations in drug metabolism, and possibly to methods to mitigate drug-induced toxicity during viral infection and design of safer retargeted viruses for therapeutic applications.