MicroRNA-146a靶向调控树突状细胞来源的exosome疫苗在防治动脉粥样硬化中的作用及其机制研究

Atherosclerosis (AS) is one of the chronic immune and inflammatory diseases. Destruction of the immune tolerance balance of the organism for the autoantigens of AS, such as ox-LDL, may lead to the development of autoimmune inflammatory reaction of AS. In previous studies, we detected that targeted up-regulation of microRNA-146a might inhibit the functional activation of dendritic cells (DC) induced by antigen impulse of ox-LDL, which resulting in formation of the antigen-specific tolerogenesis DC. The DC-derived exosomes (Dexo) which have similar functions of DC can also induce antigen-specific immune tolerance, and have more advantages than the DC vaccines as a non-cell vaccines. In this study,we regulated the microRNA-146a targeting in DC loaded with ox-LDL, immunized the AS model mice with the isolated Dexo, and then detected the effect of Dexo transfusion in vivo on the prevention and treatment of the immune and inflammatory response of AS, and further explored the possible mechanisms by which the Dexo vaccines induction of negative immune regulatory and reconstruction of antigen-specific immune tolerance of the organism for ox-LDL and thus inhibiting the development of AS. This study will provide a scientific experimental basis for the prevention and treatment of AS with a new biological and immunology way by microRNA targeted regulation of Dexo as a non-cell vaccines.

动脉粥样硬化（AS）是一种慢性免疫炎症性疾病，机体对AS自身抗原如ox-LDL免疫耐受平衡的破坏是导致AS自身免疫炎症反应发生发展的关键。我们前期的研究发现靶向上调miRNA-146a能够抑制ox-LDL抗原冲击树突状细胞（DC）所致的功能活化，使其成为抗原特异的致耐受性DC。DC来源的exosomes（Dexo）具有与DC相类似的功能，也能诱导抗原特异性免疫耐受，而且作为一种非细胞疫苗比DC疫苗更有优势。本项目研究通过miRNA-146a靶向调控DC同时负载ox-LDL，再分离获得Dexo，免疫接种AS模型小鼠，观测Dexo体内回输对AS免疫炎症反应的预防和治疗作用，进一步探讨Dexo疫苗通过诱导负性免疫调节重建机体对ox-LDL抗原特异的免疫耐受，进而防治AS发生发展的可能机制。本研究将为miRNA靶向调控Dexo作为一种非细胞疫苗从全新的生物免疫学角度防治AS提供科学的实验依据。

动脉粥样硬化（AS）是一种慢性免疫炎症性疾病，机体对AS自身抗原如ox-LDL免疫耐受平衡的破坏是导致AS自身免疫炎症反应发生发展的关键。我们前期的研究发现靶向上调miRNA-146a能够抑制ox-LDL抗原冲击树突状细胞（DC）所致的功能活化，使其成为抗原特异的致耐受性DC。DC来源的exosomes（Dexo）具有与DC相类似的功能，也能诱导抗原特异性免疫耐受，而且作为一种非细胞疫苗比DC疫苗更有优势。本项目研究通过miRNA-146a转染DC同时负载ox-LDL获得抗原特异致耐受性DC，成功制备了此种DC来源的exosomes（Dexo）并证实其同样具有抗原特异致耐受性，能抑制T淋巴细胞的增殖及免疫炎症刺激因子的分泌，从而诱导免疫耐受；通过体内回输Dexo免疫接种LDLR-/-小鼠AS模型，发现经miRNA-146a转染并负载ox-LDL抗原的Dexo预处理后虽未能降低LDLR-/-小鼠体内LDL水平，但能降低LDLR-/-小鼠血液中AS相关危险因子及炎症刺激因子的水平，同时提高炎症抑制因子的水平，并能减少LDLR-/-小鼠AS斑块内免疫炎症细胞的浸润，降低AS斑块严重程度，改善斑块稳定性。因此，miRNA-146a靶向调控的Dexo疫苗可能通过调节循环及AS斑块内免疫炎症反应，诱导机体免疫耐受，对AS具有明显的预防作用，但对于已经发生的AS无明显治疗作用。本研究将为AS的免疫炎症机制提供重要的理论支持，并将为临床研究应用miRNA靶向调控Dexo作为一种非细胞疫苗从全新的生物免疫学角度预防AS提供科学的实验依据。