HIF-1α和NSCs联合移植经外泌体转移microRNA促进NSCs存活和增殖治疗心脏骤停后脑损伤

Neural stem cell–based therapies have gained increasing interest as a potential therapy for affording neural regeneration after cardiopulmonary cerebral resuscitation. Unfortunately, progress in stem cell–based therapies has been hindered by the low percentages of transplanted cells that engraft and survive long term. Exosomes have been found to be released by various cell types. Exosomes are automatically secreted homogenous membrane vesicles, with multiple functions such as microRNAs transfer. HIF-1α has been shown to mediate activation of various adaptive responses under low levels of oxygen, including glucose metabolism, cell proliferation and cellular differentiation. Our initial study found co-delivery of NSCs with HIF-1α improve the survival and proliferation of transplanted NSCs in vitro. The NSCs had higher contents of miR-126 and miR-210. Therefore, we propose hypothesis: HIF1α can be used to modulate the host microenvironment for improving survival of transplanted cells. The exosomal transfer of microRNAs from host cells to transplanted cells represents a mechanism that can be potentially targeted for improving survival of transplanted cells and neural outcomes. Through this research, we could reveal the role and molecular mechanism of co-delivery of NSCs with HIF-1α improving the survival and proliferation of transplanted NSCs, and provide innovatory scientific theory in it.

神经干细胞(NSCs)移植是治疗心脏骤停后脑损伤的希望。但NSCs移植后长期存活率极低，成为临床应用的瓶颈问题。外泌体是由细胞分泌的囊性小泡，在细胞间microRNA传递等过程中发挥调节作用。HIF-1α与低氧条件下细胞增殖等生命过程有关。我们预实验提示：在体外低氧微环境中HIF-1α与NSCs联合移植可增加NSCs的存活率、促进其增殖，使其 miR-210和miR-126表达上调。初步提示两者联合移植在增加NSCs存活率和促进NSCs增殖中发挥调控作用，但具体机制未明。因此我们提出研究假说: HIF-1α和NSCs联合移植能增加NSCs存活率、促进NSCs增殖，其机制可能与宿主神经元产生外泌体转移miR-210、miR-126到NSCs有关。本研究可揭示HIF-1α和NSCs联合移植能否增加NSCs存活率、促进NSCs增殖并探讨其分子机制，为临床上改善心脏骤停患者的预后提供新的科学思路。

在急诊医学重点研究的领域中，由心脏骤停(Cardiac Arrest, CA)所致全脑和心肌的缺血缺氧性损伤最常见，心脏和全脑缺血再灌注后的脑保护越发受到临床医生和研究者的关注。本课题组长期致力于心肺脑复苏后心脏和全脑损伤修复的分子学和动物研究，在神经干细胞、亚低温和心脏骤停动物模型建立方面取得一系列成果。本次研究继承此前获批的国自然研究成果，结合了作为当前的国际研究热点之一的外泌体，以氯化钴和过氧化氢作为体外细胞凋亡模型，窒息为体内心脏骤停模型，大鼠作为实验用动物，亚低温作为动物实验干预手段，先后研究了以下几个内容：1）氯化钴诱导神经元凋亡；2）神经干细胞外泌体抑制低氧状态下神经元凋亡；3）低温预适应对心脏骤停大鼠脑损伤的影响；4）低温预适应对大鼠血浆外泌体的影响；5）血浆外泌体对原代神经元的保护作用及其机制；6）低温预适应通过促进线粒体自噬改善心肺复苏后心功能的机制研究。通过以上研究，本课题组在前期相关成果的基础上，以外泌体为契机，将本课题组的基础医学研究领域拓展到细胞间通讯，进一步巩固了亚低温模型和窒息模型的动物建模。基于外泌体的巨大临床治疗潜力，为今后更好的贴近临床转化和进一步研究打下了基础。依靠本课题基金的支持，先后培养了2名博士和2名硕士。