Data_Sheet_1_Intranasally delivered mesenchymal stromal cells decrease glial inflammation early in prion disease.docx

Mesenchymal stromal cells (MSCs) are an intriguing avenue for the treatment of neurological disorders due to their ability to migrate to sites of neuroinflammation and respond to paracrine signaling in those sites by secreting cytokines, growth factors, and other neuromodulators. We potentiated this ability by stimulating MSCs with inflammatory molecules, improving their migratory and secretory properties. We investigated the use of intranasally delivered adipose-derived MSCs (AdMSCs) in combating prion disease in a mouse model. Prion disease is a rare, lethal neurodegenerative disease that results from the misfolding and aggregation of the prion protein. Early signs of this disease include neuroinflammation, activation of microglia, and development of reactive astrocytes. Later stages of disease include development of vacuoles, neuronal loss, abundant aggregated prions, and astrogliosis. We demonstrate the ability of AdMSCs to upregulate anti-inflammatory genes and growth factors when stimulated with tumor necrosis factor alpha (TNFα) or prion-infected brain homogenates. We stimulated AdMSCs with TNFα and performed biweekly intranasal deliveries of AdMSCs on mice that had been intracranially inoculated with mouse-adapted prions. At early stages in disease, animals treated with AdMSCs showed decreased vacuolization throughout the brain. Expression of genes associated with Nuclear Factor-kappa B (NF-κB) and Nod-Like Receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling were decreased in the hippocampus. AdMSC treatment promoted a quiescent state in hippocampal microglia by inducing changes in both number and morphology. Animals that received AdMSCs showed a decrease in both overall and reactive astrocyte number, and morphological changes indicative of homeostatic astrocytes. Although this treatment did not prolong survival or rescue neurons, it demonstrates the benefits of MSCs in combatting neuroinflammation and astrogliosis.

间充质基质细胞（Mesenchymal stromal cells, MSCs）是治疗神经系统疾病的颇具前景的研究途径，因其能够迁移至神经炎症病灶，并通过分泌细胞因子、生长因子及其他神经调节因子响应病灶内的旁分泌信号。本研究通过炎症分子刺激间充质基质细胞，强化了其迁移与分泌特性，进而增强了上述治疗潜能。本研究在小鼠模型中探究了经鼻递送的脂肪来源间充质基质细胞（adipose-derived MSCs, AdMSCs）对抗朊病毒病的效果。

朊病毒病（prion disease）是一类罕见的致死性神经退行性疾病，由朊蛋白的错误折叠与聚集引发。该疾病的早期特征包括神经炎症、小胶质细胞激活以及反应性星形胶质细胞的形成；晚期则会出现脑空泡形成、神经元丢失、大量聚集的朊蛋白以及星形胶质细胞增生。

本研究证实，当用肿瘤坏死因子α（tumor necrosis factor alpha, TNFα）或朊病毒感染的脑匀浆刺激时，脂肪来源间充质基质细胞可上调抗炎基因与生长因子的表达。本研究使用肿瘤坏死因子α刺激脂肪来源间充质基质细胞，并对颅内接种了小鼠适应株朊病毒的小鼠进行每两周一次的经鼻递送治疗。在疾病早期，接受治疗的小鼠全脑空泡化程度均有所降低；小鼠海马体中与核因子κB（Nuclear Factor-kappa B, NF-κB）及核苷酸结合寡聚化结构域样受体蛋白3（Nod-Like Receptor family pyrin domain containing 3, NLRP3）炎症小体信号通路相关的基因表达均出现下调。脂肪来源间充质基质细胞治疗可通过改变海马体小胶质细胞的数量与形态，促进其进入静息状态；接受治疗的小鼠总星形胶质细胞与反应性星形胶质细胞数量均有所减少，且细胞形态呈现出稳态星形胶质细胞的特征。

尽管该治疗未能延长小鼠生存期或挽救神经元，但本研究证实了间充质基质细胞在对抗神经炎症与星形胶质细胞增生方面的应用价值。