Mechanism and Optimization of CBD-mediated analgesic effects

项目概要/摘要 阿尔茨海默病（AD）是一种严重的神经退行性疾病，对人类社会造成重大负担。 AD的病理特征是β-淀粉样蛋白斑块的积累和过度磷酸化， tau蛋白以及涉及小胶质细胞的神经炎症。目前还没有有效的治疗AD的方法， 因此，迫切需要基于对AD病理机制的理解的新的治疗策略。 大麻二酚（CBD）是一种非精神活性植物大麻素，具有广泛的抗炎作用。几 最近的研究报道了CBD减少神经炎症反应和改善行为的能力。 在AD小鼠模型中的功能。然而，CBD对小胶质细胞和AD的体内作用和机制 病理仍然未知。本提案的总体目标是确定以下方面的机械影响： CBD对AD相关细胞病理的影响，以优化其治疗潜力。几行 有证据表明，小胶质细胞是介导CBD体内作用的强有力的候选者， 其在AD模型中的治疗潜力。首先，淀粉样斑块周围反应性小胶质细胞的积累， 长期以来被认为是AD病理学的标志。最近的人类遗传学研究进一步确定了 多个AD风险基因参与小胶质细胞功能，暗示小胶质细胞在AD发病机制中的偶然作用。 第二，单细胞RNA测序研究揭示了AD小胶质细胞中显著的激活多样性 包括疾病相关小胶质细胞（DAM）。实验性的操作， 小胶质细胞恢复其稳态功能已显示出对AD病理学的保护作用，这表明 小胶质细胞的治疗潜力第三，已知CBD与多种膜生物化学相互作用， 受体和在小胶质细胞中表达的细胞内信号分子，包括大麻素受体。 第四，先前的体外细胞研究和我们初步的慢性体内成像数据表明，CBD调节 小胶质细胞活性和形态。CBD如何与小胶质细胞相互作用并影响AD中的淀粉样斑块 转基因模型仍有待研究。我们的中心假设是CBD治疗将改变 细胞活性和小胶质细胞的分子特征并减少脑中的AD病理。为了验证这一 假设，我们的具体目标是1）确定CBD对小胶质细胞活性和β淀粉样蛋白病理学的影响 在AD转基因小鼠模型中通过慢性体内成像，和2）评估CBD对分子水平的影响。 通过单细胞RNA测序确定AD模型中小胶质细胞的表型。确定CBD对小胶质细胞的影响 和AD相关的病理学不仅将提供新的见解的细胞和分子机制， CBD在大脑中的作用，但也提出了开发AD治疗策略的新途径。

Project Summary/Abstract Alzheimer's Disease (AD) is a severe neurodegenerative disorder that poses a major burden on human society. The pathology of AD is characterized by the accumulation of beta-amyloid plaques and hyperphosphorylated tau protein as well as neuroinflammation involving microglia. There is no effective treatment for AD currently, and new therapeutic strategies based on the mechanistic understanding of AD pathology are critically needed. Cannabidiol (CBD) is a non-psychoactive phytocannabinoid that has broad anti-inflammatory effects. Several recent studies have reported the ability of CBD to reduce neuroinflammatory responses and improve behavioral functions in AD mouse models. However, the in vivo actions and mechanisms of CBD on microglia and AD pathology remain unknown. The overall objective of this proposal is to identify the mechanistic effects of CBD on AD-related cellular pathology in order to optimize its therapeutic potentials. Several lines of evidence suggest that microglia are a strong candidate to mediate the in vivo actions of CBD and contribute to its therapeutic potentials in AD models. First, the accumulation of reactive microglia around amyloid plaques has long been recognized as a hallmark of AD pathology. Recent human genetic studies have further identified multiple AD risk genes involved in microglia function, implicating a casual role of microglia in AD pathogenesis. Second, single-cell RNA-sequencing studies have revealed significant activation diversity in AD microglia population, including disease associated microglia (DAM). Experimental manipulations that reprogram reactive microglia to restore their homeostatic functions have shown protective effects against AD pathology, suggesting the therapeutic potentials of microglia. Third, CBD is known to interact biochemically with multiple membrane receptors and intracellular signaling molecules that are expressed in microglia, including cannabinoid receptors. Fourth, prior in vitro cellular studies and our preliminary chronic in vivo imaging data show that CBD modulates microglia activity and morphology. How CBD will interact with microglia and impact amyloid plaques in AD transgenic models remains to be investigated. Our central hypothesis is that CBD treatment will alter the cellular activity and molecular profile of microglia and reduce AD pathology in the brain. To test this hypothesis, we specifically aim to 1) determine CBD's impacts on microglia activity and beta amyloid pathology in AD transgenic mouse models by chronic in vivo imaging, and 2) evaluate CBD's effects on the molecular phenotypes of microglia in AD models by single-cell RNA sequencing. Identifying the effects of CBD on microglia and AD-related pathology in vivo will not only provide novel insights into the cellular and molecular mechanisms underlying CBD's action in the brain, but also suggest new routes to develop therapeutic strategies for AD.