The Role of HSP60 in Alzheimer's Disease

阿尔茨海默病(AD)是最常见的痴呆症类型，其特征是进行性记忆丧失和 认知功能受损。这些表型的发展与细胞外b-受体的沉积有关。 淀粉样蛋白，过度磷酸化的tau蛋白在脑内的积聚，以及 线粒体生物学和功能。线粒体是否以及如何在b-淀粉样斑块的形成中发挥作用 由b-淀粉样多肽和含有磷酸-tau蛋白的神经原纤维缠结(Nft)组成，目前尚不清楚。 明白了。线粒体蛋白质稳态(线粒体蛋白稳态)是由线粒体未折叠介导的 蛋白质反应(UPRmt)。UPRmt受伴侣蛋白调节，如热休克蛋白60(HSP60)。齐聚 HSP60及其辅因子HSP10通过折叠幼稚蛋白维持线粒体蛋白稳定 以及错误折叠的蛋白质的重新折叠。我们已经通过引入一个点突变来产生一个独特的小鼠模型 通过CRISPR-Cas9方法获得成熟线粒体HSP60蛋白(HSP60D3G)的第3位点(D3G)。 HSP60D3G破坏HSP60寡聚的稳定性，导致未折叠/错误折叠的蛋白质在 线粒体。重要的是，成熟线粒体HSP60蛋白(HSP60D3G或)第3位(D3G)的点突变 HSPD1基因D29G突变)也与神经退行性疾病有关。因此，利用这一独特的 小鼠模型将解决一个关键的未得到满足的需求，以表征b-淀粉样蛋白的水平和功能意义 在破坏线粒体蛋白平衡时，磷酸-tau的积累。使用HSP60D3G敲入小鼠模型，我们 将研究AD生物学的分子洞察力和线粒体蛋白平衡缺陷的功能意义。我们 将剖析破坏线粒体蛋白平衡是否/如何导致增强的潜在机制 B-淀粉样蛋白和磷酸-tau堆积水平导致hsp60d3G小鼠认知功能下降。我们会 验证我们的假设，即线粒体蛋白平衡的失稳增强了b-淀粉样蛋白的积累 和大脑中的磷酸-tau导致HSP60D3G小鼠的AD表型。提出了两个具体的目标来测试这一点 假设。 目的1.确定有缺陷的HSP60寡聚在调节b-HSP60的细胞信号中的意义。 小鼠脑中的淀粉样蛋白和磷酸化tau蛋白。目的2.缺陷HSP60齐聚产物的功能特性 HSP60D3G小鼠的认知功能。 影响：雄激素剥夺疗法(ADT)与前列腺癌(PCA)患者AD风险增加相关。 HSP60高度上调，是前列腺癌发生和发展所必需的。因此，了解影响 对有缺陷的HSP60寡聚的了解将使我们更深入地了解发展的原因和后果 接受ADT治疗的前列腺癌患者的AD。这一发现可能提供了线粒体蛋白平衡在脑内的影响 AD生物学和预后，包括在PCa患者中，以及确定HSP60作为治疗的新靶点和 人类阿尔茨海默病的管理。

Alzheimer’s disease (AD), the most common type of dementia, is characterized by progressive memory loss and impaired cognitive function. The development of these phenotypes associates with extracellular deposition of b- amyloid peptide, accumulation of hyperphosphorylated tau (phospho-tau) protein in brain, and alteration in mitochondrial biology and function. Whether and how mitochondria play role in the formation of b-amyloid plaques, which consist of b-amyloid peptide and neurofibrillary tangles (NFTs) containing phosphor-tau protein, are not clearly understood. Mitochondrial protein homeostasis (mitochondrial proteostasis) is mediated by mitochondrial unfolded protein response (UPRmt). UPRmt is regulated by chaperones such as heat shock protein 60 (HSP60). Oligomerization of HSP60 and association with its cofactor HSP10, maintain mitochondrial proteostasis via folding of naïve proteins and refolding of misfolded proteins. We have generated a unique mouse model by introducing a point mutation at position 3 (D3G) of the mature mitochondrial HSP60 protein (HSP60D3G knock-in mice) via CRISPR-Cas9 approach. HSP60D3G destabilizes the oligomerization of HSP60 leading to the accumulation of unfolded/misfolded proteins in mitochondria. Importantly, a point mutation at position 3 (D3G) of the mature mitochondrial HSP60 protein (HSP60D3G or D29G mutation in HSPD1 gene) also associates with neurodegenerative disorder. Therefore, the utilization of this unique mouse model will address a critical unmet need to characterize the levels and functional significance of b-amyloid and phospho-tau accumulation upon disrupting the mitochondrial proteostasis. Using HSP60D3G knock-in mouse model, we will study molecular insights of AD biology and functional significance of defects in mitochondrial proteostasis. We will dissect the underlying mechanism on whether/how destabilizing mitochondrial proteostasis leads to enhanced levels of b-amyloid and phospho-tau accumulation causing decline of cognitive function in HSP60D3G mouse. We will test our hypothesis that destabilization of mitochondrial proteostasis enhances the accumulation of b-amyloid and phospho-tau in brain causing AD phenotypes in HSP60D3G mice. Two Specific Aims are proposed to test this hypothesis. Aim 1. Determine the significance of defective HSP60 oligomerization on cellular signaling that regulates b- amyloid and phospho-tau in mouse brain. Aim 2. Functional characterization of defective HSP60 oligomerization on cognitive function in HSP60D3G mice. Impact: Androgen deprivation therapy (ADT) associates with increased risk of AD in prostate cancer (PCa) patients. HSP60 is highly upregulated and required for PCa development and progression. Therefore, understanding the impact of defective HSP60 oligomerization will provide deeper understanding on the causes and consequences of developing AD in PCa patients undergoing ADT therapy. The findings may provide the impact of mitochondrial proteostasis in AD biology and prognosis including in PCa patients as well as identify HSP60 as a novel target for the treatment and management of AD in humans.