PHF15, a potential repressor of inflammation in the brain and its relevance to Alzheimer's disease

摘要 虽然阿尔茨海默氏病（AD）的遗传风险因素已经确定，但大约90%的 患者为散发病例。因此，在本提案中，我们试图了解 在建立AD的散发病例的背后。最近，我们发现一种假定的表观遗传 调节因子PHD指15（PHD 15）是调节小胶质细胞中炎症的基因的转录阻遏物。 事实上，敲除小鼠小胶质细胞中的Phf 15足以增加促炎介质， 抗病毒基因，值得注意的是，包括淀粉样前体蛋白（APP）和补体因子，在缺乏 任何刺激。因为PHF 15在人类和小鼠小胶质细胞中的mRNA表达在 健康老龄化，我们假设PHF 15表观遗传抑制小胶质细胞中年龄诱导的炎症， 未能上调PHF 15会导致神经炎症和认知能力下降。为了验证我们的假设， 我们将通过质谱法使用人来鉴定含有PHF 15的蛋白质复合物的成员。 小胶质细胞系。在使用生物化学测定确认蛋白结合后，我们将 通过建立获得和丧失功能的细胞系进行功能测定，以验证所鉴定的 复合蛋白与PHF 15合作抑制炎症。除了分离PHF 15蛋白外， 复杂，我们也将尝试确定非遗传因素，防止PHF 15 mRNA上调使用两种方法， 体内和体外模型。根据我们的初步数据，我们将重点放在病毒感染和高脂肪饮食的 体内实验以及氧化应激和感染模拟物（Toll样受体的配体， 炎性小体）用于体外实验。总的来说，这项提案的目标是确定分子 PHF 15如何抑制小胶质细胞炎症的机制，并确定非遗传因素， 阻止PHF 15表达的上调。这些结果可能有助于我们更好地了解 AD的散发病例，从而指导治疗和/或预防这一疾病的治疗策略的发展。 疾病

Abstract While genetic risk factors for Alzheimer’s disease (AD) have been identified, around ninety percent of patients are sporadic cases. Therefore, in this proposal, we seek to understand the molecular mechanisms behind the establishment of sporadic cases of AD. Recently, we have found that a putative epigenetic regulator, PHD finger 15 (PHD15), is a transcriptional repressor of genes regulating inflammation in microglia. Indeed, knockout of Phf15 in mouse microglial cells was sufficient to increase pro-inflammatory mediators and anti-viral genes, of note, including amyloid precursor protein (APP) and complement factors, in the absence of any stimuli. Because the mRNA expression of PHF15 in human and mouse microglia is increased upon healthy aging, we hypothesize that PHF15 epigenetically represses age-induced inflammation in microglia and that failure to up-regulate PHF15 results in neuroinflammation and cognitive decline. To test our hypothesis, we will identify members of the protein complex containing PHF15 by mass-spectrometry using a human microglial cell line that we have established. After confirming protein binding using biochemical assays, we will perform functional assays by establishing gain- and loss-of-function cell lines to validate whether the identified complex proteins cooperate with PHF15 to repress inflammation. In addition to isolating the PHF15 protein complex, we will also try to identify non-genetic factors that prevent PHF15 mRNA up-regulation using both in vivo and in vitro models. Based on our preliminary data, we will focus on virus infection and high-fat diet for the in vivo experiments, as well as oxidative stress and infection mimics (ligands for toll-like receptors and inflammasomes) for the in vitro experiments. Overall, the goals of this proposal are to determine the molecular mechanism behind how PHF15 represses inflammation in microglia and to identify non-genetic factors that prevent up-regulation of PHF15 expression. These results may help us to better understand the causes of sporadic cases of AD and, thus, direct the development of treatment strategies to treat and/or prevent this disease.