Endogenous retroviruses and gene regulation after injury

描述（由申请人提供）：我们已经确定了烧伤后C57 BL/6 J小鼠远端器官中鼠内源性逆转录病毒（MuERV）表达的变化（激活或抑制）。内源性逆转录病毒（ERVs）在炎症和疾病中的作用通过最近的发现来例证，即合胞素（syncytin），由人内源性逆转录病毒编码的包膜蛋白，直接参与多发性硬化的病理过程。我们的假设是，烧伤介导的某些ERV活性的改变有助于全身反应，特别是烧伤后的免疫紊乱。这些ERV通过其逆转录病毒活性和基因产物以及改变其整合位点附近的相邻细胞基因的表达来发挥病理作用。目的1：建立C57 BL/6 J小鼠基因组中MuERV的染色体图谱。这一目标将在计算机上进行MuERVs的染色体定位，评价其编码逆转录病毒多肽的潜力，并鉴定邻近单个前病毒基因座的细胞基因。目的2将集中于确定具有相同U3启动子序列的每组MuERV的体外转录潜力。由于负责MuERV表达的关键转录调控元件主要位于高度多态性的U3启动子序列上，因此将通过荧光素酶报告基因测定和转录调控元件分析来确定每组U3启动子的转录活性。在目标3中，将分析MuERV的病理生理作用，其表达响应于烧伤/应激信号在烧伤后免疫紊乱中被调节。最初，为了鉴定可能在烧伤后免疫紊乱中起作用的MuERVs，将检查远端器官以及体循环中逆转录病毒表达的改变。将构建携带特异性U3序列的重组MuERV，其转录活性响应于烧伤和/或应激信号而改变，并且将在体外细胞培养以及体内感染模型中研究这些MuERV在烧伤后免疫病症中的作用。来自这些研究的数据可以阐明开发新的治疗方案的替代方向（例如，逆转录病毒逆转录酶抑制剂、蛋白酶抑制剂）在烧伤、创伤、细菌感染和其它类型应激条件下调节内源性逆转录病毒活性方面的作用。

DESCRIPTION (provided by applicant): We have identified changes (activation or repression) in the expression of murine endogenous retroviruses (MuERVs) in distant organs of C57BL/6J mice after burn. A role for endogenous retroviruses (ERVs) in inflammation and disease is exemplified by the recent finding that syncytin, an envelope protein encoded by a human endogenous retrovirus, is directly involved in the pathologic processes of multiple sclerosis. It is our hypothesis that burn-mediated alterations in activities of certain ERVs contribute to the systemic response, particularly the immune disorder after burn. These ERVs exert pathologic effects via their retroviral activities and gene products as well as altering expression of neighboring cellular genes near their integration sites. In aim 1, we will establish a chromosomal map of MuERVs in the genome of C57BL/6J mice. This aim will perform in silico chromosomal mapping of MuERVs, evaluation of their coding potentials for retroviral polypeptides, and identification of cellular genes neighboring individual proviral loci. Aim 2 will focus on determination of the transcriptional potential of each group of MuERVs sharing the same U3 promoter sequence in vitro. Because the key transcriptional regulatory elements responsible for the expression of MuERVs reside mainly on the highly polymorphic U3 promoter sequences, transcriptional activities from each group of U3 promoters will be determined by luciferase reporter assay and transcription regulatory element analysis. In aim 3, the pathophysiologic roles of MuERVs whose expression is modulated in response to burn/stress signals in the post-burn immune disorder will be analyzed. Initially, to identify MuERVs which may play a role in the post-burn immune disorder, alterations in retroviral expression in distant organs as well as the systemic circulation will be examined. Recombinant MuERVs that carry specific U3 sequences whose transcriptional activities are altered in response to burn and/or stress signals will be constructed and the role of these MuERVs in the post-burn immune disorder will be investigated in vitro cell culture as well as in vivo infection model. The data from these studies may elucidate an alternative direction for the development of a novel therapeutic regimen (e.g., retroviral reverse transcriptase inhibitor, protease inhibitor) in regard to the modulation of endogenous retroviral activities under the conditions of burn, trauma, bacterial infection, and other types of stresses.