IGF-1 signaling pathway in HIV-1 in CNS disease

二号工程。HIV-1 CMS疾病中的IGF-1信号通路。 相当多的艾滋病毒患者会出现认知障碍和痴呆症。据信， HIV-1感染细胞在白色物质中释放的病毒因子，最明显的是TNF α， 艾滋病患者大脑中的神经元损伤。因此，我们证明， 向TNFa c诱导分化的神经元导致在缺乏神经元分化的情况下神经元突起的收缩。 凋亡HIV-1感染还可以损害神经保护途径，包括胰岛素样生长 因子1（IGF-1）信号系统。因此，在早期的研究中，我们证明IGF-1可以保护 TNF α诱导的神经元突起回缩。我们已经证明了TNF α会触发 IRS-1（pS-IRS-1）在分化神经元膜筏上的丝氨酸磷酸化，pSIRS-1在分化神经元膜筏上的丝氨酸磷酸化， 1干扰整合素介导的细胞反应，这直接参与维持 神经过程和神经生长。 这些观察使我们假设，在HIV脑炎中，神经元过程的变性是 由TNF α诱导的pS-IRS-1和神经元整合素之间的相互作用引起，其导致分离 和神经突起的收缩。TNF α的这种有害作用被IGF-I介导的TNF α抑制。 IRS-1的酪氨酸磷酸化（pY-IRS-1），其支持神经元过程的结合， 促进组织重塑和神经元生长。我们已经通过实验证实了这一假设 具体目标有三个。在目标1中。我们将分析神经元过程的密度在区域 HIV脑炎（HIVE）受TNF α积累的不同影响。在目标#2中。我们将评估 TNF α对IRS-1的亚细胞定位和磷酸化状态的影响;并将分析分子生物学特性。 胰岛素样生长因子-IR基因敲除的原代神经元培养物中IRS-1、β 1-整联蛋白和亚当斯之间的相互作用 胚胎和来自年龄匹配的非转基因同窝仔。最后，目标#3。我们将研究 IGF-I刺激对TNF α介导的牵拉后神经元再生和组织重塑的影响 来自IGF-IR敲除胚胎和来自年龄匹配的分化神经球培养物中的神经元突起 非转基因同窝仔。该项目的结果将确定和表征新的分子 事件，其影响HIVE范例中的神经元过程的稳定性，以及可能的其他神经系统事件。 以TNFa积累为特征的疾病。了解IGF-1之间的交叉作用 和TNFa信号通路将有助于开发新的基于IGF-1的治疗方法， 其中神经元过程的回缩/变性是常见事件的神经病症。

Project #2. IGF-1 signaling pathway in HIV-1 CMS disorders. A significant number of HIV patients develop cognitive disorders and dementia. It is believed that cellular and viral factors released by the HIV-1 infected cells in the white matter, most notably TNFa , are responsible for neuronal injury seen in AIDS brains. Accordingly, we demonstrated that prolonged exposure of differentiated neurons to TNFoc leads to the retraction of neuronal processes in the absence of neuronal apoptosis. HIV-1 infection can also compromise neuroprotective pathways including the insulin-like growth factor 1 (IGF-1) signaling system. Accordingly, in earlier studies we demonstrated that IGF-1 protects neurons from TNFa-induced retraction of neuronal processes. We have demonstrated that TNFa triggers serine phosphorylation of IRS-1 (pS-IRS-1) at the membrane rafts of differentiated neurons, and that pSIRS- 1 interferes with integrin-mediated cellular responses, which are directly involved in the maintenance of neuronal processes and neuronal outgrowth. These observations led us to hypothesize that in HIV encephalitis degeneration of neuronal processes is caused by TNFa-induced interaction between pS-IRS-1 and neuronal integrins, which leads to detachment and retraction of neuronal processes. This detrimental action of TNFoc is counteracted by IGF-l-mediated tyrosine phosphorylation of IRS-1 (pY-IRS-1), which supports the binding of neuronal processes and facilitates tissue remodeling and neuronal outgrowth. We have addressed this hypothesis by experiments described in three Specific Aims. In Aim#1. we will analyze density of neuronal processes in the regions of HIV encephalitis (HIVE) differentially affected by the accumulation of TNFoc. In Aim#2. we will evaluate effects of TNFcc on subcellular localization and phosphorylation status of IRS-1; and will analyze molecular interactions between IRS-1, (31-integrin and ADAMs in primary neuronal cultures from the IGF-IR knockout embryos and from age-matching non-transgenic littermates. Finally, in Aim#3. we will examine effects of IGF-I stimulation on neuronal regeneration and tissue remodeling after TNFa -mediated retraction of neuronal processes in differentiated neurosphere cultures from the IGF-IR knockout embryos and from agematching non-transgenic littermates. The outcome of this project will identify and characterize new molecular events, which affect stability of neuronal processes in the paradigm of HIVE, and possibly other neurological disorders characterized by the accumulation of TNFcc. Understanding the cross interaction between IGF-1 and TNFa signaling pathways will help to develop new IGF-l-based therapeutic approaches against neurological disorders in which retraction/degeneration of neuronal processes is a common event.