Microglia Cytokines and HIV

描述（由申请人提供）：toll样受体（TLRs）已成为免疫细胞上介导对病原体的先天免疫的关键受体。TLRs通过MyD88（一种包含TLR-IL-1受体结构域（TIR）的接头分子）发出信号，激活NF-KB和MAP激酶。在TLR家族的11个成员中，TLR3和TLR4还通过另一种称为TRIP的TIR蛋白发出信号，该蛋白激活关键转录因子IRF3，导致IFNb的产生。这引发了大量ifn刺激基因的诱导，最终产生抗病毒免疫。TLR配体和IL-1是小胶质细胞和星形胶质细胞调节炎症和抗病毒反应基因的强大激活剂，但它们在抗病毒免疫中的作用及其所涉及的信号转导途径尚不清楚。我们观察到TLR3配体，合成dsRNA，多核糖素多核糖素酸（PIC），限制了HIV在小胶质细胞和星形胶质细胞中的复制，而IL- 1，也激活IRF3和类似PIC的基因阵列，却没有。在这一竞争性更新中，我们提出研究人类初级胶质细胞中的dsRNA信号传导，假设在HIV感染期间，TLR3被上调，但由于缺乏可用的配体和/或HIV的抑制而没有有效的dsRNA信号传导。我们进一步提出PIC可用于增强体内抗病毒免疫。提出了三个具体目标。特异性目的1是阐明TLRS信号转导通路在人类星形胶质细胞和小胶质细胞中导致先天抗病毒免疫反应的机制。特异性目的2是在体外确定pic诱导的人类胶质细胞和神经元中HIV复制、胶质细胞炎症激活和神经毒性的调节。特异性目的3是表征PIC和hiv诱导的基因在体内的表达和活性。我们将在HIV转基因小鼠模型中研究PIC诱导TLR3和抗病毒分子的功效。此外，还将确定tlr和先天免疫分子在HIV脑炎脑组织中的表达情况。这些研究将为PIC及其下游效应物（如吲哚胺2,3 -双加氧酶）在调节HIV神经发病机制的各个方面的潜在作用提供分子见解。这些研究与公共卫生相关，因为它们将提供关于人类脑细胞如何对抗病毒感染的关键信息，此外，它们可能会导致神经艾滋病的新疗法。由于大脑中含有像小胶质细胞这样的长期感染HIV的细胞，因此从这个部位清除HIV也可能导致治愈HIV/ aids。

DESCRIPTION (provided by applicant): Toll-like receptors (TLRs) have emerged as crucial receptors on immune cells that mediate innate immunity against pathogens. TLRs signal through MyD88, an adaptor molecule containing the TLR-IL-1 receptor domain (TIR), to activate NF-KB and MAP kinases. Of the 11 members of the TLR family, TLR3 and TLR4 also signal through another TIR protein called TRIP that activates the key transcription factor IRF3 resulting in the production of IFNb. This sets off the induction of numerous IFN-stimulated genes, culminating in anti- viral immunity. TLR ligands and IL-1 are powerful activators of microglia and astrocytes modulating inflammatory and antiviral response genes, yet their role in anti-viral immunity and the signal transduction pathways involved are not known. We made a novel observation that the TLR3 ligand, synthetic dsRNA, poly-riboinosinic poly-ribocytidylic acid (PIC), limits HIV replication in microglia and astrocytes, whereas IL- 1, which also activates IRF3 and the arrays of genes similar to PIC, does not. In this competing renewal, we propose to study dsRNA signaling in primary human glia with the hypothesis that during HIV infection, TLR3 is upregulated but no effective dsRNA signaling occurs due to lack of available ligands and/or inhibition by HIV. We further propose that PIC can be used to boost antiviral immunity in vivo. Three specific aims are proposed. Specific Aim 1 is to elucidate TLRS signal transduction pathways in human astrocytes and microglia with respect to the mechanisms that lead to innate anti-viral immune response. Specific Aim 2 is to determine PIC-induced modulation of HIV replication, glial inflammatory activation and neurotoxicity in human glia and neurons in vitro. Specific Aim 3 is to characterize PIC- and HIV-induced gene expression and activity in vivo. We will study the efficacy of PIC to induce TLR3 and antiviral molecules in an HIV transgenic mouse model. In addition, the expression of TLRs and innate immune molecules in the brains of HIV encephalitis will be determined. These studies will provide molecular insights into the potential role of PIC and its downstream effectors such as indoleamine 2, 3-dioxygenase in modulating various aspects of HIV neuropathogenesis. These studies are relevant to public health because they will provide crucial information regarding how human brain cells fight against viral infections, and furthermore, they may lead to a new therapy for neuroAIDS. Since the brain harbors long-lived HIV- infected cells such as microglia, eradication of HIV from this site could also lead to cure of HIV/AID.