ACUTE MYOCARDITIS--ROLES OF REOVIRUS AND INTERFERON BETA

急性病毒性心肌炎是一种重要的人类疾病。 而 肠道病毒引起免疫介导的损伤， 其他病毒引起的心肌炎仍在很大程度上未被探索。呼肠孤病毒- 诱导的鼠心肌炎不是由免疫细胞功能决定的， 为研究非免疫介导的心肌炎提供了理想的模型。 我们的数据表明，不同的诱导和敏感性， 干扰素-β（IFN-β）在心肌细胞中是 呼肠孤病毒引起的心肌炎，并确定这些活动 通过参与RNA合成的呼肠孤病毒核心蛋白。 IFN提供了一种 是抵御病毒感染的第一道防线 病毒rna 合成刺激调节IFN-β转录的细胞因子。 分泌的IFN结合受体并诱导IFN应答基因， 介导干扰素的抗病毒作用，但其中一些需要双重 链-[ds] RNA激活。IFN-γ的诱导和敏感性 β高度依赖于病毒株和细胞类型，然而， 还没有研究心脏IFN对病毒的反应。 我们的第一 假设是呼肠孤病毒对IFN-β不同诱导 感染通过PKR的差异诱导或激活来确定， IRF-1和/或IRF-2。 在具体目标1中，我们将确定PKR是否 （dsRNA活化的蛋白激酶）、IRF-1（IFN调节因子-1）和/或 IRF-2，每种都调节其他病毒/细胞中的IFN-β诱导 系统，调节呼肠孤病毒诱导IFN-β在原发性心脏 肌细胞培养，我们将使用基因敲除小鼠来研究它们的 体内的作用。 在具体目标2中，我们将使用两种额外的细胞类型 以识别细胞特异性反应。第二个假设是， 对IFN-α/β的不同敏感性是由于 PKR，2 '，5'-寡腺苷酸的激活和/或敏感性 合成酶和/或RNA酶L。 在具体目标3中，我们将确定 是否这三个因素，其中每一个都需要dsRNA激活， 在其他病毒/细胞系统中的抗病毒作用，介导呼肠孤病毒 在原代心肌细胞培养物中对IFN-α/β的敏感性，和 我们将使用基因敲除小鼠来研究它们在体内的作用。 在 具体目标4，我们将使用两种额外的细胞类型，如上所述。 呼肠孤病毒提供了一个独特的工具，调查干扰素反应调用 由心脏中密切相关的病毒引起。 我们的工作将是第一个 确定作为心脏IFN应答决定因素的细胞因子 和心肌炎。

Acute viral myocarditis is an important human disease. While enteroviruses cause immune-mediated damage, the mechanisms by which other viruses induce myocarditis remain largely unexplored. Reovirus- induced murine myocarditis is not determined by immune cell function, and presents an ideal model for studying nonimmune mediated myocarditis. Our data suggest that differential induction of and sensitivity to interferon-beta (IFN-beta) in cardiac myocytes are determinants of reovirus-induced myocarditis, and that these activities are determined by reovirus core proteins involved in RNA synthesis. IFN provides a critical first line of defense against viral infection. Viral RNA synthesis stimulates cell factors which regulate IFN-beta transcription. Secreted IFN binds receptors and induces IFN-responsive genes which mediate IFN's antiviral effects, but several of these require double stranded-[ds]RNA activation. Both induction of and sensitivity to IFN- beta are highly dependent on virus strain and cell type, and yet, there have been no studies on the cardiac IFN response to viruses. Our first hypothesis is that differential induction of IFN-beta by reovirus infection is determined by differential induction or activation of PKR, IRF-1, and/or IRF-2. In Specific Aim 1, we will determine whether PKR (dsRNA activated protein kinase), IRF-1 (IFN regulatory factor-1) and/or IRF-2, each of which regulate IFN-beta induction in other virus/cell systems, regulate reovirus induction of IFN-beta in primary cardiac myocyte cultures, and we will use knockout mice to investigate their roles in vivo. In Specific Aim 2, we will use two additional cell types to identify cell-specific responses. Our second hypothesis is that differential sensitivity to IFN-alpha/beta is due to differential activation of and/or sensitivity to PKR, 2',5'-oligoadenylate synthetase, and/or RNase L. In Specific Aim 3, we will determine whether these three factors, each of which requires dsRNA activation for antiviral effects in other virus/cell systems, mediate reovirus sensitivity to IFN-alpha/beta in primary cardiac myocyte cultures, and we will use knockout mice to investigate their roles in vivo. In Specific Aim 4, we will use two additional cell types, as above. Reoviruses offer a unique tool to investigate the IFN response invoked by closely related viruses in the heart. Our work will be the first to identity cell factors that are determinants of this cardiac IFN response and myocarditis.