Protein misfolding and accumulation defines a prevailing feature of many neurodegenerative disorders, finally resulting in the formation of toxic intra- and extracellular aggregates. Intracellular aggregates can enter the extracellular space and be subsequently transferred among different cell types, thus spreading between connected brain districts. Although microglia perform a predominant role in the removal of extracellular aggregated proteins, mounting evidence suggests that astrocytes actively contribute to the clearing process. However, the molecular mechanisms used by astrocytes to remove misfolded proteins are still largely unknown. Here we first provide a brief overview of the progressive transition from soluble monomers to insoluble fibrils that characterizes amyloid proteins, referring to α-Synuclein and Tau as archetypical examples. We then highlight the mechanisms at the basis of astrocyte-mediated clearance with a focus on their potential ability to recognize, collect, internalize and digest extracellular protein aggregates. Finally, we explore the potential of targeting astrocyte-mediated clearance as a future therapeutic approach for the treatment of neurodegenerative disorders characterized by protein misfolding and accumulation.

中文翻译：

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蛋白质聚集体的大脑清除：星形胶质细胞的特写

蛋白质错误折叠和积累是许多神经退行性疾病的普遍特征，最终导致有毒的细胞内和细胞外聚集物的形成。细胞内聚集物可以进入细胞外空间，随后在不同细胞类型之间转移，从而在相连的大脑区域之间传播。尽管小胶质细胞在清除细胞外聚集蛋白方面发挥着主要作用，但越来越多的证据表明星形胶质细胞积极参与清除过程。然而，星形胶质细胞用于去除错误折叠蛋白质的分子机制仍然很大程度上未知。在这里，我们首先简要概述从可溶性单体到不溶性原纤维的逐渐转变，这是淀粉样蛋白的特征，以 α-突触核蛋白和 Tau 为典型例子。然后，我们强调星形胶质细胞介导的清除基础上的机制，重点关注它们识别、收集、内化和消化细胞外蛋白质聚集体的潜在能力。最后，我们探索了以星形胶质细胞介导的清除为目标的潜力，作为治疗以蛋白质错误折叠和积累为特征的神经退行性疾病的未来治疗方法。