CPT2 F352C突变通过MAVS/STING通路加重EV71脑炎脑干损害的机制研究

EV71 encephalitis can cause severe brain stem damage, however, its pathogenesis is still unclear and the treatment is limited. The autoimmune function of host plays an important role in the occurrence and prognosis of EV71 encephalitis. CPT2 is one of the key enzymes in fatty acid oxidation. In previous study, we found CPT2 F352C mutation was significantly associated with the severity of EV71 encephalitis. In pilot experiments, we found CPT2 enzyme activity and ATP levels decreased in CPT2 F352C mutant astrocytes after EV71 infection and hyperthermia, mitochondria antiviral signaling protein and its pathways were blocked, and production of type Ⅰ interferon in host immune cells reduced. And these resulted in that EV71 could escape from the antiviral reaction of host immune cells and brain tissue damage of EV71 encephalitis could be aggravated. To verify this hypothesis, we intended to use astrocytes and mouse models with CPT2 F352C point mutation which had been established successfully to analyze the effects of CPT2 dysfunction on MAVS/STING pathway related protein expression and the pathological damage of brain stem. The abnormal expression above will be verified in peripheral blood mononuclear cells from patients with CPT2 F352C mutation. In this study, we will try to reveal the new pathogenesis of brain stem damage in EV71 encephalitis and provide theoretical basis for exploring new preventive and therapeutic methods.

EV71脑炎可致严重脑干损害，其发病机理不清，治疗措施有限。宿主的自身免疫功能对该疾病的发生及预后起重要作用。前期研究发现脂肪酸氧化关键酶CPT2的F352C突变与EV71脑炎的严重性明显相关。体外预实验结果显示，含CPT2 F352C突变的星型胶质细胞的酶活性和ATP水平在EV71感染及高热时降低，线粒体抗病毒信号蛋白及其通路被阻断，宿主免疫细胞的Ⅰ型干扰素产出降低，从而导致EV71逃逸宿主免疫细胞的抗病毒反应而加重EV71脑炎脑组织损害。为验证该假说，本课题拟采用已制备成功的含CPT2 F352C点突变的星型胶质细胞和小鼠模型，分别从体外和体内研究CPT2功能异常对MAVS/STING通路相关蛋白功能及脑干病理损害的影响；并利用CPT2 F352C突变病人的外周血单核细胞验证上述机理。该研究将深入揭示EV71脑炎脑干损害的机制，为探索新的防治方法提供理论依据。

EV71感染引起的脑炎可致严重脑干损害，致死率和致残率高，但其发病机理不清，治疗措施有限。宿主的自身免疫功能对该疾病的发生及预后起重要作用。有前期研究发现脂肪酸氧化关键酶CPT2的F352C突变与EV71脑炎的严重性明显相关。体外预实验结果显示，含CPT2 F352C突变的星型胶质细胞的酶活性和ATP水平在EV71感染及高热时降低，线粒体抗病毒信号蛋白及其通路被阻断，宿主免疫细胞的Ⅰ型干扰素产出降低，从而导致EV71逃逸宿主免疫细胞的抗病毒反应而加重EV71脑炎脑组织损害。在本课题组拟采用已制备成功的含CPT2 F352C点突变的星型胶质细胞和小鼠模型，分别从体外和体内研究CPT2功能异常对MAVS/STING通路相关蛋白功能及脑干病理损害的影响；并利用CPT2 F352C突变病人的外周血单核细胞验证上述机理。通过我们的实验研究发现：携带有CPT2 F352C突变的小鼠和细胞，在感染EV71病毒后，小鼠出现严重的EV71脑炎症状，星形胶质细胞出现细胞膜破碎、死亡等现象。高热处理的携带CPT2 F352C突变的小鼠更容易引发重症脑炎，且感染高热情况下突变小鼠较野生型CPT2、MAVS、STING、TRAF3等基因表达下降，同时感染的突变小鼠在发生高热情况下CPT2、MAVS、STING、TRAF3等基因表达较非高热小鼠下降。