Neuron - glial communication and brain aging

这个项目的一个主要主题是了解导致慢性UP状态的原因和条件- 衰老过程中促炎过程的调节是神经退行性变的背景 疾病就会发生。我们已经证明趋化因子Fractalkine(FKN)的丢失是一种早期事件 大脑老化，这加速了对促炎信号的偏爱，如ILI3和TNFa。 Fractalkine(CX3CL1)表达于神经元，其受体(CX3CR1)位于小胶质细胞上。结扎术 CX3CR1可下调11-1？、肿瘤坏死因子α等促炎细胞因子的表达。我们将研究 对CX3CL1的调节，因为它既以裂解的可溶性形式存在，又以膜结合的形式存在。的确有 膜结合形式和可溶性形式控制免疫调节的不同方面的证据， 然而，人们对此知之甚少。为了解决这个问题，我们生成了rAAV9向量，以表达 1)可溶的，2)天然的和3)未裂解的突变体CX3CL1。我们将使用这些独特而新颖的工具来 了解这些形式的FKN在控制小胶质细胞功能中的作用及其对神经调节的作用 以神经发生、长时程增强(LTP)和认知功能为指标测量衰老小鼠的可塑性 CX3CL1缺陷小鼠确定早期(12个月)更换FKN是否会导致国王 持续调节小胶质细胞功能，防止天然免疫功能随年龄和年龄的增加而增加 神经可塑性和认知功能丧失。在目标2中，我们将检查神经特异性细胞与星形胶质细胞 CX3CL1的特异性表达改变了其功能特性。CX3CL1通常用神经符号表示， 然而，在某些条件下，已经在星形胶质细胞中观察到了它。在目标3中，我们将进一步了解 CX3CL1及其受体可能与M1和M2对刺激的反应随着年龄的增长而相互作用，就像我们所做的那样 观察到老年人大脑对IL4/IL13的迟钝反应。我们将在CX3CR1 NULL和 CX3CL1基因缺失小鼠以及正常衰老的C57BL/6小鼠。我们将为体外细胞分离原代小胶质细胞 培养实验以确定M1和M2反应调节的任何变化是否是细胞自主的 或非细胞自主的。

A major theme of this project is understanding the causes and conditions that lead to a state of chronic up- regualtion of pro-inflammatory process in aging that are the backround within which neurodegeneartive disease occurs. We have demonstrated that loss of the chemokine fractalkine (FKN) is an early event in brain aging and that this precipitates a bias towards pro-inflammatory signals such as ILI3 and TNFa. Fractalkine (CX3CL1) is expressed in neurons and the receptor (CX3CR1) is on microglia. Ligation of CX3CR1 results in down regulation of 11-1 ß, TNFα and other pro-inflammatory cytokines. We will examine regulation of CX3CL1 as it is present as both a cleaved soluble form and a membrane bound form. There is evidence that the membrane bound form and the soluble form control different aspects of immune regulation, however this is poorly understood. To address this question we have generated rAAV9 vectors that express 1 )soluble, 2) native and 3) a mutant uncleaved CX3CL1. We will use these unique and novel tools to understand the role these forms of FKN in control of microglial function and its role to regulate neural plasticity measured as neurogensis and long term potentiaion (LTP) and cognitive function in aged mice and CX3CL1 deficient mice to determine if replacement of FKN at an early age (12 months) will lead to king lasting regulation of microglial function and prevent increased innate immune function with age and preverit a loss in neural plasticity and cognitive function. In aim 2 we will examine if neural specific versus astrocyte specific expression of CX3CL1 alters the functional properties. CX3CL1 is normally epxressed in nuerons, hoever under certain conditions it has been observed in astrocytes. In aim 3 we will then look further at the role of CX3CL1 and its receptor as it may interact with Ml and M2 responses to stimuli with age, as we have observed blunted responses to iL4/IL13 in the aged brain. We will examine this in the CX3CR1 null and CX3CL1 null mice as well as normal aged C57BL/6 mice. We will isolate primary microglia for ex vivo cell culture experiments to determine if any changes in regulation of M1 and M2 responses are cell autonomous or non cell autonomous.