Parkinson’s disease (PD) is the second most common neurodegenerative disorder. The etiology of the disease remains largely unknown, but evidence have suggested that the overexpression and aggregation of alpha-synuclein (α-syn) play key roles in the pathogenesis and progression of PD. Mesenchymal stromal cells (MSCs) have been earning attention in this field, mainly due to their paracrine capacity. The bioactive molecules secreted by MSCs, i.e. their secretome, have been associated with enhanced neuronal survival as well as a strong modulatory capacity of the microenvironments where the disease develops. The selection of the appropriate animal model is crucial in studies of efficacy assessment. Given the involvement of α-syn in the pathogenesis of PD, the evidence generated from the use of animal models that develop a pathologic phenotype due to the action of this protein is extremely valuable. Therefore, in this work, we established an animal model based on the viral vector-mediated overexpression of A53T α-syn and studied the impact of the secretome of bone marrow mesenchymal stromal cells MSC(M) as a therapeutic strategy. Adult male rats were subjected to α-syn over expression in the nigrostriatal pathway to model dopaminergic neurodegeneration. The impact of locally administered secretome treatment from MSC(M) was studied. Motor impairments were assessed throughout the study coupled with whole-region (striatum and substantia nigra) confocal microscopy evaluation of histopathological changes associated with dopaminergic neurodegeneration and glial cell reactivity. Ten weeks after lesion induction, the animals received secretome injections in the substantia nigra pars compacta (SNpc) and striatum (STR). The secretome used was produced from bone marrow mesenchymal stromal cells MSC(M) expanded in a spinner flask (SP) system. Nine weeks later, animals that received the viral vector containing the gene for A53T α-syn and treated with vehicle (Neurobasal-A medium) presented dopaminergic cell loss in the SNpc and denervation in the STR. The treatment with secretome significantly reduced the levels of α-syn in the SNpc and protected the dopaminergic neurons (DAn) within the SNpc and STR. Our results are aligned with previous studies in both α-syn Caenorhabditis elegans models, as well as 6-OHDA rodent model, revealing that secretome exerted a neuroprotective effect. Moreover, these effects were associated with a modulation of microglial reactivity supporting an immunomodulatory role for the factors contained within the secretome. This further supports the development of new studies exploring the effects and the mechanism of action of secretome from MSC(M) against α-syn-induced neurotoxicity.

中文翻译：

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在动态系统中培养的骨髓间充质基质细胞的分泌组在 α-突触核蛋白过表达大鼠模型中诱导神经保护并调节小胶质细胞反应性

帕金森病 (PD) 是第二常见的神经退行性疾病。该疾病的病因尚不清楚，但有证据表明 α-突触核蛋白 (α-syn) 的过度表达和聚集在 PD 的发病机制和进展中发挥着关键作用。间充质基质细胞（MSC）在该领域引起了人们的关注，主要是由于它们的旁分泌能力。间充质干细胞分泌的生物活性分子，即它们的分泌蛋白组，与神经元存活率的提高以及疾病发生的微环境的强大调节能力有关。选择合适的动物模型对于疗效评估研究至关重要。鉴于 α-syn 参与 PD 的发病机制，使用由于该蛋白质的作用而形成病理表型的动物模型所产生的证据非常有价值。因此，在这项工作中，我们建立了基于病毒载体介导的A53T α-syn过表达的动物模型，并研究了骨髓间充质基质细胞MSC（M）的分泌组作为治疗策略的影响。成年雄性大鼠在黑质纹状体通路中进行 α-syn 过度表达，以建立多巴胺能神经变性模型。研究了 MSC(M) 局部施用分泌组治疗的影响。在整个研究过程中评估了运动障碍，并结合全区域（纹状体和黑质）共聚焦显微镜评估与多巴胺能神经变性和神经胶质细胞反应性相关的组织病理学变化。损伤诱导十周后，动物在黑质致密部（SNpc）和纹状体（STR）中接受分泌蛋白组注射。所使用的分泌组是由在转瓶（SP）系统中扩增的骨髓间充质基质细胞MSC（M）产生的。九周后，接受含有 A53T α-syn 基因的病毒载体并用媒介物（Neurobasal-A 培养基）处理的动物表现出 SNpc 中的多巴胺能细胞损失和 STR 中的去神经支配。分泌组治疗显着降低了 SNpc 中的 α-syn 水平，并保护了 SNpc 和 STR 内的多巴胺能神经元 (DAn)。我们的结果与之前在 α-syn 线虫模型和 6-OHDA 啮齿动物模型中的研究结果一致，表明分泌蛋白组发挥了神经保护作用。此外，这些效应与小胶质细胞反应性的调节有关，支持分泌组中所含因子的免疫调节作用。这进一步支持了探索 MSC(M) 分泌蛋白组对抗 α-syn 诱导的神经毒性的作用和作用机制的新研究的发展。