背景:大脑中α-Syn突变引起的蛋白质错误折叠和包涵体聚集通常会引起神经变性和认知障碍,其中A53T点突变较为常见。抑制腺苷A2A受体(A2AR)可以缓解A53T-α-Syn原纤引起的脑功能障碍的病理症状,但其作用机制尚不清楚。
目的:本研究旨在研究A2AR抑制剂KW6002在脑突触核蛋白病小鼠模型中的潜在治疗作用。
方法:将A53T-α-Syn纤维前体细胞核蛋白注入小鼠双侧前额叶皮质,建立突触核蛋白病动物模型,腹腔注射A2AR抑制剂KW6002(5mg/kg)进行干预。
结果:脑内注射A53T-α-Syn原纤维触发脑内包涵体的形成,导致星形胶质细胞激活,凋亡细胞的数量增加,和抑制自噬通量。KW6002的施用显著逆转了这些现象。体外实验表明,A53T-α-Syn原原纤维抑制小鼠海马神经元细胞HT-22自噬,而KW6002增加细胞自噬通量,上调LAMP2A和Hsc70蛋白的表达,抑制SQSTM1蛋白的表达。本研究提示KW6002通过抑制A2AR蛋白降低α-Syn磷酸化水平,同时,增强神经元细胞的自噬通量,导致A53T-α-Syn原原纤维降解,从而减少A53T-α-Syn原原纤维诱导的神经元毒性和凋亡。
结论:KW6002对A53T-α-Syn诱导的神经元损伤具有明显的保护作用。
BACKGROUND: Protein misfolding and inclusion body aggregation caused by α-Syn mutations in the brain often cause neurodegeneration and cognitive impairment, among which the A53T point mutation is more common. Inhibition of adenosine A2A receptor (A2AR) can alleviate the pathological symptoms of brain dysfunction caused by A53T-α-Syn protofibrils, but the mechanism of action is still unclear.
OBJECTIVE: This studies aimed to investigate the potential therapeutic role of the A2AR inhibitor KW6002 in a mouse model of brain synucleinopathy.
METHODS: A53T-α-Syn fibre precursor cell nuclear protein was injected into the bilateral prefrontal cortex of mice to establish a synucleinopathy animal model, and the A2AR inhibitor KW6002 (5 mg/kg) was injected intraperitoneally to intervene.
RESULTS: The intracerebral injection of A53T-α-Syn protofibrils triggers the formation of inclusion bodies in the brain, leading to astrocyte activation, an increased number of apoptotic cells, and suppression of autophagic flux. The administration of KW6002 significantly reversed these phenomena. In vitro experiments revealed that A53T-α-Syn protofibrils inhibited HT-22 autophagy in mouse hippocampal neuronal cells, whereas KW6002 increased cellular autophagic flux, upregulated the expression of LAMP2A and Hsc70 proteins and inhibited the expression of SQSTM1 protein. The present study suggests that KW6002 reduces the level of α-Syn phosphorylation by inhibiting A2AR protein, at the same time, enhances the autophagic flux of neuronal cells, resulting in the degradation of A53T-α-Syn protofibrils and thus reducing the neuronal toxicity and apoptosis induced by A53T-α-Syn protofibrils.
CONCLUSIONS: KW6002 has a significant protective effect on neuronal injury induced by A53T-α-Syn.