Neuroprotection by IFN-beta in AIDS

 描述(申请人提供)：感染人类免疫缺陷病毒(HIV)-1可导致痴呆症，目前尚无治疗方法。一些证据有力地表明，神经变性的发生是由于HIV-1感染和脑内小胶质细胞和巨噬细胞(MΦ)的神经毒性免疫刺激和神经发生的损害。HIV-1还会触发包括产生干扰素(IFN)在内的先天免疫反应。干扰素β被认为与控制脑内艾滋病毒感染有关，并具有显著的抗炎作用。在之前的资助期间，我们发现：首先，对HIV/gp120转基因(TG)小鼠的中枢神经系统基因表达分析显示，干扰素反应有限。HIV/gp120tg的大脑在1岁半时瞬时表达干扰素β，但在3或6个月龄时不表达，此时出现神经病理和行为障碍。其次，我们发现一个四周的鼻腔(I.N.)从3.5月龄开始的干扰素β治疗完全防止了艾滋病毒/gp120tg小鼠的神经元损伤。第三，干扰素β通过早期诱导CCl_3来保护体外培养的神经元免受艾滋病毒/gp120的神经毒性，这种毒性在小胶质细胞存在的情况下发生得最有效。在这一新的应用中，我们建议表征：1)内源性干扰素应答的贡献；2)干扰素α/β受体1(IFNAR1)和干扰素刺激基因(ISGs)在干扰素β对抗HIV-1或gp120毒性的神经保护中的细胞类型特异性作用。我们推测干扰素β可以通过诱导神经保护性干扰素刺激基因(如IRF1和CCL3)和抑制炎症反应来保护神经元免受HIV-1/gp120的毒性和维持行为功能。本研究的具体目的是：(1)在体内研究内源性干扰素β对HIV/gp120转基因小鼠模型神经元损伤的影响以及动物对鼻腔注射干扰素β治疗的反应。(2)体内检测小胶质细胞、星形胶质细胞或神经元的干扰素α/β受体1(IFNAR1)是否是干扰素β抗HIV/Gp120毒性所必需的。(3)评价持续外源性干扰素β能否通过诱导抗病毒Φ亚群来抑制HIV-1感染和M-ISG的神经毒性。针对特定目标1和2，干扰素β 将通过鼻腔给药，这允许在将药物输送到大脑的同时绕过血脑屏障。在缺乏内源性干扰素β或其受体IFNAR1的转基因小鼠中，将比较干扰素β和赋形剂治疗的转基因小鼠基于记忆和认知的行为表现、神经元损伤和胶质形成。我们还将评估哪种神经细胞类型(S)需要与干扰素β相互作用，以保存记忆和认知，并在艾滋病毒/Gp120存在的情况下减少胶质细胞增生。具体目标3将使用核糖核酸测序确定神经毒性艾滋病毒-1感染MΦ的核糖核酸特征，并将测试外源干扰素β可以克服艾滋病毒-1下调抗病毒因子和产生神经毒素的前提。这三个特异性靶点都将检验以下假设：干扰素β诱导神经保护性β趋化因子，增加AKT活性，降低p38MAPK活性，从而保护神经元及其树突和突触免受艾滋病毒或gp120诱导的小胶质细胞和MΦ的毒性。

 DESCRIPTION (provided by applicant): Infection with Human Immunodeficiency virus (HIV)-1 can induce dementia for which currently no treatment is available. Several lines of evidence strongly suggest that neurodegeneration occurs as a consequence of HIV-1 infection and neurotoxic immune stimulation of microglia and macrophages (MΦ) in the brain and impairment of neurogenesis. HIV-1 also triggers an innate immune response that includes production of interferons (IFNs). IFNβ has been implicated in the control of HIV infection in the brain and has pronounced anti-inflammatory effects. In the previous funding period we found: First, a CNS gene expression analysis of HIV/gp120 transgenic (tg) mice revealed a limited IFN response. HIV/gp120tg brains transiently expressed IFNβ at 1.5 but not 3 or 6 months of age when neuropathology and behavioral impairment developed. Second, we found that a four-week intranasal (i.n.) IFNβ treatment starting at 3.5 months of age completely prevented neuronal damage in HIV/gp120tg mice. Third, IFNβ protected neurons in vitro against neurotoxicity of HIV/gp120 by early induction of CCL3, which occurred most efficiently in the presence of microglia. In this renewal application we propose to characterize i) the contribution of the endogenous IFN response and ii) the cell type-specific role of IFNα/β receptor 1 (IFNAR1) and IFN-stimulated genes (ISGs) in neuroprotection by IFNβ against toxicity of HIV-1 or gp120. We hypothesize that IFNβ can protect neurons from HIV-1/gp120 induced toxicity and preserve behavioral performance by a mechanisms, comprising induction of neuroprotective IFN-stimulated genes (ISG) such as IRF1 and CCL3 and inhibition of inflammation. The specific aims are: (1) To study in vivo how endogenous IFNβ affects neuronal damage in a HIV/gp120 transgenic mouse model and the animals' response to intranasal IFNβ treatment. (2) To examine in vivo whether the interferon α/β receptor 1 (IFNAR1) of microglia or astrocytes or neurons are necessary for neuroprotection by IFNβ against toxicity of HIV/gp120. (3) To assess whether a continuous supply of exogenous IFNβ can restrict HIV-1 infection and the associated neurotoxicity of MΦ via induction of a subset of anti-viral ISGs. For Specific Aims 1 and 2, IFNβ will be administered via an intranasal route, which allows bypassing the blood brain barrier while delivering the drug to the brain. Memory and cognition-based behavioral performance, neuronal injury and gliosis will be compared in IFNβ- versus vehicle-treated HIV/gp120-transgenic mice lacking endogenous IFNβ or its receptor IFNAR1. We will also assess which neural cell type(s) are required to interact with IFNβ in order to preserve memory and cognition and to reduce gliosis in the presence of HIV/gp120. Specific Aim 3 will define an RNA signature of neurotoxic HIV-1 infected MΦ using RNA-sequencing and will test the premise that exogenous IFNβ can overcome the down- regulation of antiviral factors and production of neurotoxins by HIV-1. All three Specific Aims will test the premise that IFNβ induces neuroprotective β-chemokines, increases activity of Akt and reduces activity of p38 MAPK, and thus protects neurons and their dendrites and synapses from HIV or gp120-induced toxicity of microglia and MΦ.