Is Toll-like receptor-3 signaling involved in Alzheimer's disease?

描述（由申请人提供）：该项目将检查Toll样受体-3（TLR-3）表达的功能后果，因为它与阿尔茨海默病的特征有关。Toll样受体是一个由10种模式识别受体组成的家族，在协调宿主防御微生物方面具有多种功能。我们确定TLR-3在AD脑中由小胶质细胞显著表达，特别是斑块相关的小胶质细胞，而其他显著的TLR与胶质细胞无关。由于TLR-3信号转导可能具有不同的后果，我们认为在AD和相关的相关人类模型系统中进行研究是及时的。由于TLR-3主要是一种内体定位的受体，其功能及其激活AD的后果需要研究。我们基于初步结果开发了一个中心假设，即用TLR-3配体刺激小胶质细胞和星形胶质细胞将诱导抗炎和保护性反应，并促进A？去除。作为刺激， 尽管已经提出了相关的内体TLR-9作为从脑中去除淀粉样蛋白的治疗选择，但我们假定TLR-3活化可能具有类似的结果。该项目的目标是确定小胶质细胞和星形胶质细胞在A？存在下对TLR-3配体反应的性质。这将在来自死后大脑的小胶质细胞和星形胶质细胞培养物以及离体人脑切片培养物中进行体外研究。我们还将确定是否慢性TLR-3配体管理斑块发展的转基因小鼠影响A负荷和相关的神经病理学。我们将在三个相关目标中研究这些特征。具体目标1;我们将研究TLR-3激活人类小胶质细胞和星形胶质细胞对促炎和抗炎细胞因子和神经毒性因子产生的功能后果。AD和正常脑的培养物将在A？存在和不存在的情况下用TLR-3配体刺激。我们将使用抗体阵列来测量细胞反应，并进行体外神经毒性和神经保护试验来确定TLR-3刺激的后果。具体目标2;我们将研究TLR-3激活人类小胶质细胞和星形胶质细胞对淀粉样β肽的摄取和降解的功能后果。这两个目的都将使用目的1中所述的TLR 3-配体聚IC和/或A β刺激的人小胶质细胞和星形胶质细胞在体外进行。具体目标3;我们将使用两个复杂的系统，其中发生小胶质细胞，星形胶质细胞和神经元的相互作用，以研究与目标1和2相同的特征。我们将使用人类大脑和淀粉样斑块发育转基因小鼠的体外切片培养物来确定TLR-3激活是否促进或减少炎症和神经元存活，以及增加或减少胶质细胞对A？的摄取和降解。 公共卫生相关性：这项研究与公共卫生的相关性在于，它可以识别阿尔茨海默病炎症的新特征。我们认为，激活人脑中的Toll样受体-3可能是治疗的目标。目前，我们不知道在阿尔茨海默病中是否需要增强或抑制这种信号传导，有证据表明这两种特征;然而，任何一种都可能是改变神经退行性疾病中炎症反应路径的重要方法。这些发现不仅与阿尔茨海默氏症有关，还与其他神经退行性疾病有关。

DESCRIPTION (provided by applicant): This project will examine the functional consequences of Toll-like receptor-3 (TLR-3) expression as it relates to features of Alzheimer's disease. Toll-like receptors, which are a family of 10 related pattern recognition receptors, have multiple functions in coordinating host defenses to microbial agents. We identified TLR-3 as being prominently expressed by microglia in AD brains, particularly those plaque-associated, while other significant TLR were not associated with glia. As TLR-3 signaling can have different consequences, we consider it timely to investigate in AD and related relevant human model systems. As TLR-3 is primarily an endosomal localized receptor, its function and the consequence of its activation to AD requires investigation. We have developed a central hypothesis based on preliminary results that stimulation of microglia and astrocytes with ligands for TLR-3 will induce anti-inflammatory and protective responses, and also promote A¿ removal. As stimulation of related endosomal TLR-9 has been suggested as a therapeutic option for removing amyloid from brain, we are positing that TLR-3 activation may have similar outcome. The goal of this project is to identify the nature of microglia and astrocyte responses to TLR-3 ligands in the presence of A¿. This will be investigated in vitro in microglia and astrocyte cultures derived from postmortem brains, and in ex-vivo human brain slice cultures. We will also determine if chronic TLR-3 ligand administration to plaque-developing transgenic mice affects A¿ load and related neuropathology. We will investigate these features in three related aims. Specific Aim 1; We will investigate what are the functional consequences of TLR-3 activation of human microglia and astrocytes on production of proinflammatory and anti-inflammatory cytokines and neurotoxic factors. Cultures from AD and normal brains will be stimulated with a TLR-3 ligand in the presence and absence of A¿. We will use antibody arrays to measure cellular responses, and also in vitro neurotoxicity and neuroprotective assays to determine consequences of TLR-3 stimulation. Specific Aim 2; We will investigate what are the functional consequences of TLR-3 activation of human microglia and astrocytes on uptake and degradation of amyloid beta peptide. Both aims will be carried out in vitro using the TLR3- ligand poly IC and/or A¿ stimulated human microglia and astrocytes described in Aim 1. Specific Aim 3; We will use two complex systems, where interactions of microglia, astrocytes and neurons occur, to investigate the same features as in aims 1 and 2. We will use ex vivo slice cultures of human brains and also amyloid plaque developing transgenic mice to determine whether TLR-3 activation promotes or reduces inflammation and neuronal survival, and increases or decreases glial uptake and degradation of A¿. PUBLIC HEALTH RELEVANCE: The relevance of this research to public health is that it could identify new features of inflammation in Alzheimer's disease. We are positing that activation of Toll-like receptor-3 in the human brain could be a target for treatment. At present, we do not know if this signaling needs to be enhanced or inhibited in Alzheimer's disease, there is evidence for both features; however either could be significant approaches to changing the path of inflammatory responses in neurodegeneration. These findings will not only be relevant for Alzheimer's but other neurodegenerative diseases.