Neuron - glial communication and brain aging

该项目的一个主要主题是了解导致慢性上升状态的原因和条件， 调节促炎症过程中的老化，这是背景，其中神经退行性疾病 疾病发生。我们已经证明，趋化因子Fractalkine（FKN）的缺失是一个早期事件， 脑老化，并且这沉淀了对促炎信号如ILI 3和TNFa的偏好。 Fractalkine（CX 3CL 1）在神经元中表达，受体（CX 3CR 1）在小胶质细胞上。结扎 CX 3CR 1导致11-1 β、TNFα和其他促炎细胞因子的下调。我们将研究 CX 3CL 1以裂解的可溶形式和膜结合形式存在时，CX 3CL 1的调节。有 有证据表明膜结合形式和可溶形式控制免疫调节的不同方面， 但人们对此知之甚少。为了解决这个问题，我们已经产生了表达 1）可溶的，2）天然的和3）突变的未切割的CX 3CL 1。我们将使用这些独特而新颖的工具， 了解这些形式的FKN在控制小胶质细胞功能中的作用及其在调节神经元功能中的作用。 可塑性测量为老年小鼠的神经发生和长时程增强（LTP）和认知功能， CX 3CL 1缺陷小鼠，以确定在早期（12个月）更换FKN是否会导致King 持久调节小胶质细胞功能，防止先天免疫功能随年龄增长而增加， 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与星形胶质细胞 CX 3CL 1的特异性表达改变了功能特性。CX 3CL 1通常在神经元中表达， 然而在某些条件下，在星形胶质细胞中观察到了这种现象。在目标3中，我们将进一步研究 CX 3CL 1及其受体的作用，因为它可能与M1和M2对年龄刺激的反应相互作用，正如我们所做的那样， 在老年脑中观察到对IL 4/IL 13的迟钝反应。我们将在CX 3CR 1 null中检查这一点， CX 3CL 1缺失小鼠以及正常老年C57 BL/6小鼠。我们将分离原代小胶质细胞用于体外细胞培养， 培养实验，以确定M1和M2反应调节中的任何变化是否是细胞自主的 或非细胞自主。

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.