Investigating a neuroprotective role of GBA in astrocytes

帕金森病（PD）的一个关键特征是大脑神经元内的异常蛋白质聚集。 这些神经元蛋白质聚集体随着PD的进展而扩散到整个神经系统，但这是如何发生的呢？ 发生的情况尚不清楚。最近的研究表明，星形胶质细胞，支持神经功能，通过提供 能量和保护免受细胞应激，也可能在PD和其他疾病中具有神经保护作用。 神经退行性疾病这项提议调查了基因GBA的潜在新作用， PD的遗传风险因素也与疾病进展更快相关。虽然大多数关于GBA的研究 专注于其在神经元中的作用，我们将测试GBA是否需要在星形胶质细胞摄取， 降解细胞外基质中的神经元衍生蛋白以减少致病性神经元的增殖 蛋白质聚集体。 我们最近的工作使用我们的果蝇GBA缺陷模型（GBADel）的PD表明，外泌体是一个 介导蛋白质聚集扩散的重要载体。GBA缺乏失调外泌体形成， 融合和/或内容。令人惊讶的是，我们发现野生型GBA的神经胶质表达可以减少蛋白质的表达。 存在于GBADel果蝇脑中的聚集。为了进一步研究GBA可能的神经保护作用， 星形胶质细胞，我们将使用从人类诱导多能干细胞分化的培养神经元和星形胶质细胞 来自携带GBA突变的PD患者。年龄和性别匹配的无关健康对照， 通过CRISPR/Cas9将GBA突变回复为野生型产生的等基因对照将用作对照。 我们将首先确定GBA是否对星形胶质细胞摄取和神经源性EV的加工很重要 通过检查GBA PD相对于对照星形胶质细胞的摄取和含有GBA PD的神经元EV的细胞内运输， 突触核蛋白-GFP融合蛋白。然后，我们将测试GBA是否在星形胶质细胞中具有神经保护作用， 将GBA PD或对照星形胶质细胞与GBA PD或对照神经元一起培养并检测蛋白质聚集， 两种细胞类型中的内溶酶体运输和细胞存活。这项研究的结果可以揭示新的 治疗目标，以增强星形胶质细胞的神经保护功能，导致治疗， 或阻止PD和以蛋白质聚集体为特征的其它神经变性疾病的进展。

A key feature of Parkinson’s disease (PD) is abnormal protein aggregation within neurons in the brain. These neuronal protein aggregates spread throughout the nervous system as PD progresses, but how this occurs remains unclear. Recent work suggests that astrocytes, which support neuronal function by providing energy and protection from cellular stressors, may also have a neuroprotective role in PD and other neurodegenerative diseases. This proposal investigates a potential new role for the gene GBA, a common genetic risk factor for PD that is also associated with faster disease progression. While most studies of GBA focus exclusively on its role in neurons, we will test whether GBA is required in astrocytes to uptake and degrade neuronal-derived proteins in the extracellular matrix to reduce propagation of pathogenic neuronal protein aggregates. Our recent work using our Drosophila GBA deficient model (GBAdel) of PD indicates that exosomes are an important vehicle mediating the spread of protein aggregation. GBA deficiency dysregulates exosome formation, fusion, and/or content. Surprisingly, we found that glial expression of wildtype GBA can reduce protein aggregation present in GBAdel fly brains. To further investigate a possible neuroprotective role for GBA in astrocytes, we will use cultured neurons and astrocytes differentiated from human induced pluripotent stem cells generated from PD patients carrying GBA mutations. Unrelated healthy age- and sex-matched control and isogenic controls generated by CRISPR/Cas9 reversion of the GBA mutation to wildtype will be used as controls. We will first determine whether GBA is important for astrocyte uptake and processing of neuronal-derived EVs by examining GBA PD versus control astrocyte uptake and intracellular trafficking of neuronal EVs containing synuclein-GFP fusion protein. We will then test whether GBA has a neuroprotective role in astrocytes by co- culturing GBA PD or control astrocytes with GBA PD or control neurons and examine protein aggregation, endolysosomal trafficking and cell survival in both cell types. The results from this study could uncover new therapeutic targets to enhance the neuroprotective function of astrocytes, leading to treatments that could slow or halt the progression of PD and other neurodegenerative diseases characterized by protein aggregates.