Mechanisms of Interferon-alpha Neurotoxicity

全世界有超过3500万艾滋病毒携带者。多达50%的艾滋病毒感染者 尽管联合使用抗逆转录病毒药物，个体仍会患上HIV相关的神经认知障碍(HAND) 治疗(购物车)。然而，自CART问世以来，艾滋病毒相关痴呆症的发病率是最严重的 手的形式，已经减少，在Cart所在的美国等国家只占不到5%的手 可用。因此，手部的轻度形式，如无症状的神经认知障碍和轻度 神经认知障碍，现在占主导地位。最终，这些轻微的手型会导致HIV相关 痴呆症及其严重后果。此外，由于感染艾滋病毒的人寿命更长，他们 容易患上阿尔茨海默氏症等与年龄相关的疾病，这会加重手部疾病。因此， 必须开发辅助疗法(对CART)。脑脊液中干扰素-α升高 并与认知功能障碍相关。包括临床和基础研究在内的研究已经 已证实干扰素α具有神经毒性，可导致认知功能障碍和神经元树突异常。我们的 研究表明，干扰素α可能成为手部辅助治疗的靶点。 在SCID小鼠中建立了手部模型，并形成了翻译的重要部分 本提案的组成部分。这个模型展示了与人类的行为相似之处。模型 在研究发病机制和开发新的治疗方法方面一直是有用的。最近的改进 在治疗前后使用物体识别测试使我们能够确定行为的逆转 通过新的治疗方法产生的异常。模型的这一方面特别重要，因为它反映了温和的 认知障碍在人类中是最常见的形式，并因此模拟了发生在 人体临床试验。因此，手部模型是一种有价值的新的临床前筛选工具。 辅助疗法。此外，干扰素α在手小鼠的大脑中升高，而阻断手小鼠的干扰素α是一种 可能被证明对手部病人有效的有效治疗。然而，中和人类体内的干扰素α可能会 由于潜在的副作用，最终不切实际。因此，大鼠神经元培养被用来研究 干扰素α的神经毒性机制。通过研究干扰素α的神经毒性机制，新的治疗方法 手部的治疗，也许还有其他认知障碍，可能会被开发出来。 研究表明干扰素α的神经毒性是通过干扰素α受体(IFNAR)和 NMDA受体(NMDAR)。大鼠神经细胞暴露于干扰素α后，树突状细胞长度和 分支。最近的研究表明，PSD-95沿树突的斑点减少，提示更具特异性 毒性机制。蛋白质组学显示arf1、cdc42和β-catenin减少，这是至关重要的。 与树突棘支架密切相关的细胞内信号蛋白。Arf1减少显示 通过蛋白质组学，通过蛋白质印迹得到了验证。PSD-95稳定NMDAR和AMPA受体 因此，在干扰素α潜在地将其与arf1、cdc42和可能的β-连环蛋白联系起来后，PsD-95降低。验证后 Cdc42和β-catenin减少，我们将在神经元培养中[个别]过度表达它们。 暴露于干扰素α以确定过度表达是否纠正了PSD-95的下降。 我们还假设，由于干扰素α减少了脊柱上的PSD-95，这导致了内化 体外和体内的AMPA受体。这最终会导致神经元网络的破坏，减少 可塑性和长期抑郁会导致认知能力低下。我们计划调查以下方面的相对贡献 IFNAR和NMDAR对这些效应的影响，最终相信这两种受体都有作用，任何 未来手部的辅助治疗将需要解决这两个受体。

Worldwide there are over 35 million individuals living with HIV. As many as 50% of these HIV-infected individuals will develop HIV associated neurocognitive disorders (HAND), despite combined antiretroviral therapy (cART). Yet, since the advent of cART the incidence of HIV associated dementia, the most severe form of HAND, has diminished and represents less than 5% of HAND in countries like the US where cART is available. Therefore, mild forms of HAND, such as Asymptomatic Neurocognitive Impairment and Mild Neurocognitive Disorder, now predominate. Eventually these mild forms of HAND lead to HIV associated dementia and its severe consequences. In addition, because HIV-infected individuals are living longer, they are susceptible to age related diseases like Alzheimer’s disease, which can exacerbate HAND. Consequently, adjunctive therapies [to cART] must be developed. Interferon-alpha (IFNα) is elevated in the cerebrospinal fluid of HAND patients and correlates with cognitive dysfunction. Studies, including both clinical and basic, have established that IFNα is neurotoxic causing cognitive dysfunction and neuronal dendritic abnormalities. Our investigations suggest that IFNα could be a target for adjunctive therapies for HAND. A model of HAND in SCID mice was developed and forms an important part of the translational component of this proposal. This model demonstrates behavioral similarities to HAND in humans. The model has been useful in studying pathogenesis and the development of novel treatments. Recent improvements using object recognition testing before and after treatment enable us to determine reversal of behavioral abnormalities by novel therapies. This aspect of the model is particularly important because it reflects mild cognitive impairment in humans with HAND, the most common forms, and thus models conditions occurring in human clinical trials. As a result, the HAND model represents a valuable tool for pre-clinical screening of novel adjunctive therapies. Also, IFNα is elevated in brains of HAND mice and blocking IFNα in HAND mice is an effective treatment that may prove effective in HAND patients. Nevertheless, neutralizing IFNα in humans may not be ultimately practical due to potential side effects. Therefore, rat neuronal cultures are used to study the mechanisms of IFNα neurotoxicity. By studying the mechanisms of IFNα neurotoxicity, novel approaches to treatment of HAND, and perhaps other cognitive disorders, may be developed. Studies have shown that IFNα neurotoxicity is mediated through both the IFNα receptor (IFNAR) and the NMDA receptor (NMDAR). Rat neurons exposed to IFNα exhibit decreases in dendritic length and branching. Recent work demonstrates decreased PSD-95 puncta along dendrites, suggesting more specific mechanisms of toxicity. Proteomics demonstrate decreases in Arf1, Cdc42, and β-catenin, which are critical intracellular signaling proteins that are intimately involved in dendritic spine scaffolding. Arf1 decreases shown by proteomics have been verified through Western blotting. PSD-95 stabilizes NMDAR and AMPA receptors and thus PSD-95 decreases after IFNα potentially link it to Arf1, Cdc42 and possibly β-catenin. After validation that Cdc42 and β-catenin are decreased, we will overexpress all of them [individually] in neuronal cultures exposed to IFNα to determine if overexpression corrects PSD-95 decreases. We also hypothesize that because IFNα decreases PSD-95 on the spine, this leads to internalization of AMPA receptors both in vitro and in vivo. This ultimately results in disruption of neuronal networks, decreased plasticity, and long-term depression leading to poor cognition. We plan to investigate the relative contribution of the IFNAR and NMDAR to these effects, with the ultimate belief that both receptors contribute and that any future adjunctive treatments for HAND will need to address both receptors.