Neuroinflammation during cerebral Toxoplasma gondii infection

项目总结 弓形虫是一种细胞内寄生虫，感染全球三分之一的人类，并可导致 HIV/AIDS患者合并感染期间的疾病。这些寄生虫会造成长期的脑部感染， 感染的重新激活会在免疫受损的艾滋病毒/艾滋病患者中引起弓形体脑炎。T. 弓形虫是艾滋病患者最常见的机会性寄生虫感染之一，也是主要原因。 合并艾滋病的中枢神经系统局灶性感染。尽管T细胞对T细胞的保护性免疫是必不可少的。 最近的证据表明，包括单核细胞在内的髓系细胞在宿主防御中也发挥着关键作用。 在弓形虫慢性感染期间，炎性单核细胞从血液到中枢神经系统的运输 对于防止脑弓形体病的宿主保护至关重要。尽管单核细胞在中枢神经系统中的重要作用 对弓形虫感染的免疫力，对驱动单核细胞的趋化因子知之甚少 脑内单核细胞介导的神经炎性反应的结果。 我们最近对小鼠的弓形虫感染进行了全脑成像和神经解剖学分析， 这表明炎性单核细胞以高度区域化的方式渗透到大脑中， 优先定位于嗅结节，这是一个参与气味引导行为的多感官大脑区域， 社交和奖励认知，以及行为灵活性。这项建议的目标是确定 在弓形虫感染过程中驱动神经炎症的分子线索及其定义结果 对寄生虫和大脑驻留细胞的反应。日本弓形虫慢性复活感染模型的建立 将使用老鼠。在这个模型中，慢性感染的小鼠受到免疫抑制以诱导 寄生虫重新激活，从而模拟艾滋病毒/艾滋病患者的免疫妥协。在目标1中，我们将 弓形虫慢性感染和复活过程中小鼠脑内炎性单核细胞和弓形虫的定位 对受感染转基因的光学透明、完整的脑进行光片显微镜观察的感染 老鼠。我们还将评估星形胶质细胞CCL2在中枢神经系统炎性单核细胞浸润中的作用。 利用星形胶质细胞产生CCL2缺陷的小鼠控制寄生虫。在目标2中，我们将定义结果 在弓形虫感染期间寄生虫和大脑驻留细胞上的局灶性神经炎性反应。 我们将研究小胶质细胞和星形胶质细胞的激活，抗微生物iNOS和IRG蛋白的水平，以及 单核细胞浸润率高、低的脑区寄生虫负荷。我们还将不偏不倚地进行 RNA-Seq分析比较高水平和低水平单核细胞浸润性脑区以确定 感染期间神经炎症对转录图谱的影响。这项研究具有重要的意义 因为局灶性神经炎可能是多种中枢神经系统病理的基础，包括艾滋病毒脑病。 了解神经炎症是如何调节的，将有助于我们基本理解 与艾滋病毒/艾滋病相关的免疫缺陷对中枢神经系统生物学的神经炎症。

PROJECT SUMMARY Toxoplasma gondii is an intracellular parasite that infects one-third of humans worldwide and can cause fatal disease during co-infection of HIV/AIDS patients. The parasites establish a long-term brain infection, and reactivation of the infection causes Toxoplasmic encephalitis in immune-compromised HIV/AIDS patients. T. gondii is among the most common opportunistic parasitic infections in AIDS patients and is the leading cause of focal CNS infection complicating AIDS. Although T cells are essential for protective immunity against T. gondii, recent evidence indicates that myeloid cells, including monocytes, also play a key role in host defense. The trafficking of inflammatory monocytes from the blood to the CNS during chronic T. gondii infection is critical for host protection against cerebral toxoplasmosis. Despite the important role of monocytes in CNS immunity against T. gondii infection, remarkably little is known about the chemokines that drive monocyte infiltration to the brain or the outcome of the neuroinflammatory response mediated by monocytes in the brain. We recently performed a brain-wide imaging and neuroanatomical analysis of T. gondii infection in mice, which revealed that inflammatory monocytes infiltrate the brain in a highly regionalized manner and preferentially localize to the olfactory tubercle, a multisensory brain region involved in odor-guided behavior, social and reward cognition, and behavioral flexibility. The objective of this proposal is to determine the molecular cues that drive neuroinflammation during T. gondii infection and to define the outcome of this response on the parasites and brain-resident cells. A model of chronic and reactivated T. gondii infection in mice will be used. In this model, chronically-infected mice are subject to immune suppression to induce parasite reactivation, thereby modeling the immune compromise of HIV/AIDS patients. In Aim 1, we will localize inflammatory monocytes and T. gondii in the brains of mice during chronic and reactivated T. gondii infection by performing light sheet microscopy on optically transparent, intact brains from infected transgenic mice. We will also evaluate a role for astrocyte CCL2 in inflammatory monocyte infiltration of the CNS and in parasite control by using mice deficient in astrocyte production of CCL2. In Aim 2, we will define the outcome of the focal neuroinflammatory response on the parasites and on brain-resident cells during T. gondii infection. We will investigate microglia and astrocyte activation, the levels of antimicrobial iNOS and IRG proteins, and parasite burden in brain regions with high and low monocyte infiltration. We will also conduct an unbiased RNA-Seq analysis comparing brain regions with high and low levels of infiltrating monocytes to determine the effects of neuroinflammation on the transcriptional landscape during infection. This research is significant because focal neuroinflammation may underlie a variety of CNS pathologies, including HIV encephalopathies. An understanding of how neuroinflammation is regulated will inform our basic understanding of the effects of neuroinflammation on CNS biology in the context of immune deficiency associated with HIV/AIDS.