Virologic and Immunologic Studies of Murine CMV Retinitis

描述（由申请方提供）：随着高效抗逆转录病毒治疗（HAART）的广泛使用，人类免疫缺陷病毒（HIV）感染患者的巨细胞病毒视网膜炎发病率下降。然而，尽管这种减少，但仍有HIV感染患者存在CMV视网膜炎的风险，因为他们没有/不能遵循抗HIV药物的处方治疗方案。因此，对CMV发病机制的深入了解有可能转化为预防或改善治疗仍有发生CMV视网膜炎风险的患者。在本申请中，使用小鼠，小鼠组织，和培养的细胞被提出来破译小鼠巨细胞病毒（MCMV）视网膜炎的几个特征的机制，包括从外层视网膜连续感染的过程（通过睫状体上途径接种病毒后，病毒可进入视网膜下腔）以及从小鼠和人类研究中观察到的巨细胞病毒感染的细胞通常不经历细胞凋亡。本申请中提出的研究将利用最近在理解细胞凋亡途径以及巨细胞病毒如何与宿主相互作用以诱导视网膜损伤方面的进展。第一个具体目标将确定RPE细胞的感染如何诱导上覆视网膜中的细胞凋亡。这一目的将检验以下假设：在MCMV视网膜炎期间，受感染的RPE细胞产生iNOS和NO开始视网膜感染和损伤的级联反应。这一目标也将使我们能够确定TNF-1在RPE初始感染过程中的作用。第二个具体目标将确定TNF-1和NO分别通过半胱天冬酶依赖性和半胱天冬酶非依赖性途径引起未感染视网膜细胞凋亡的程度。这一目标将测试的假设，半胱天冬酶依赖性以及半胱天冬酶非依赖性细胞凋亡有助于视网膜病变在MCMV视网膜炎。第三个特异性目的将确定为什么MCMV感染的视网膜细胞不发生凋亡。该目的将检验MCMV立即早期蛋白3（IE-3）通过上调细胞FLICE抑制蛋白（c-FLIP）在保护感染细胞免于凋亡中起重要作用的假设。这些研究的结果将提供有关视网膜MCMV感染机制的新信息，这些信息可能适用于预防视网膜巨细胞病毒感染或减少人类患者视网膜损伤的新治疗方法。公共卫生相关性：随着高效抗逆转录病毒治疗（HAART）的广泛应用，人类免疫缺陷病毒（HIV）感染患者中巨细胞病毒视网膜炎的发病率有所下降。然而，尽管这种减少，但仍有HIV感染患者存在巨细胞病毒视网膜炎的风险，因为他们没有/不能遵循抗HIV药物的处方治疗方案或他们的病毒变得耐药。对巨细胞病毒感染发病机制的进一步了解有可能转化为对仍有发生CMV视网膜炎风险的患者的预防或改善治疗。拟议的研究结果将提供有关视网膜巨细胞病毒感染机制的新信息，这些信息可能适用于预防视网膜感染和/或减少视网膜损伤的新治疗方法。

DESCRIPTION (provided by applicant): The incidence of cytomegalovirus retinitis has decreased in human immunodeficiency virus (HIV)-infected patients concomitant with the widespread use of highly actively antiretroviral therapy (HAART). However despite this decrease, there are HIV infected patients who are still at risk for CMV retinitis because they do not/cannot follow the prescribed therapeutic regimen of anti-HIV drugs. Therefore, an increased understanding of the mechanisms underlying the pathogenesis of CMV has the potential for translation into preventative or ameliorative treatments in patients who are at still at risk for developing CMV retinitis. In this application, a combination of in vitro and in vivo studies using mice, mouse tissues, and cultured cells are proposed to decipher the mechanism of several features of murine cytomegalovirus (MCMV) retinitis including the process of sequential infection from the outer retina (following inoculation of virus via the supraciliary route which allows the virus to gain access to the subretinal space) to the inner retina and the observation from both mouse and from human studies that cytomegalovirus infected cells usually do not undergo apoptosis. The studies proposed in this application will take advantage of recent advances in understanding apoptotic pathways and in how cytomegalovirus may interact with the host to induce retinal damage. The first specific aim will determine how infection of RPE cells induces apoptosis in the overlying retina. This aim will test the hypothesis that production of iNOS and NO by infected RPE cells begins the cascade of retinal infection and damage during MCMV retinitis. This aim will also allow us to determine the contribution of TNF-1 during initial infection of the RPE. The second Specific Aim will determine to what extent TNF-1 and NO cause apoptosis of uninfected retinal cells via caspase-dependent and caspase-independent pathways, respectively. This aim will test the hypothesis that caspase-dependent as well as caspase-independent apoptosis contributes to retinal pathology during MCMV retinitis. The third Specific Aim will determine why MCMV infected retinal cells do not undergo apoptosis. This aim will test the hypothesis that MCMV immediate early protein 3 (IE-3) plays an important role in protecting infected cells from apoptosis by upregulating the cellular FLICE-inhibitory protein (c-FLIP). The results of these studies will provide new information about the mechanisms of MCMV infection of the retina which may be applicable to new therapeutic approaches to prevent cytomegalovirus infection of the retina or to reduce retinal damage in human patients. PUBLIC HEALTH RELEVANCE: The incidence of cytomegalovirus retinitis has decreased in human immunodeficiency virus (HIV)-infected patients concomitant with the widespread use of highly actively antiretroviral therapy (HAART). Despite this decrease however, there are HIV infected patients who are still at risk for cytomegalovirus retinitis because they do not/cannot follow the prescribed therapeutic regimen of anti-HIV drugs or their virus becomes drug resistant. Increased understanding of the mechanisms underlying the pathogenesis of cytomegalovirus infections has the potential for translation into preventative or ameliorative treatments in patients who are at still at risk for development of CMV retinitis. Results of the proposed studies will provide new information about the mechanisms of cytomegalovirus infection of the retina which may be applicable to new therapeutic approaches to prevent retinal infection and/or to reduce retinal damage.