Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, No.58 Zhongshan Road 2, Guangzhou 510080, China.
Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou 510663, China.
Exp Neurol. 2025 Jan;383:115020. doi: 10.1016/j.expneurol.2024.115020. Epub 2024 Oct 18.
Cognitive impairment is often found at the acute stages and sequelae of coronavirus disease 2019 (COVID-19), and the underlying mechanisms remain unclear. The S1 protein from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be a cause of cognitive impairment associated with COVID-19. The nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome and neuroinflammation play important roles in Alzheimer's disease (AD) with cognitive impairment. However, their roles remain unknown in COVID-19 with cognitive impairment. We stimulated BV2 cells with S1 protein in vitro and injected the hippocampi of wild-type (WT) mice, NLRP3 knockout (KO), and microglia NLRP3 KO mice in vivo with S1 protein to induce cognitive impairment. We assessed exploratory behavior as associative memory using novel object recognition and Morris water maze tests. Neuroinflammation was analyzed using immunofluorescence and western blotting to detect inflammatory markers. Co-localized NLRP3 and S1 proteins were investigated using confocal microscopy. We found that S1 protein injection led to cognitive impairment, neuronal loss, and neuroinflammation by activating NLRP3 inflammation, and this was reduced by global NLRP3 KO and microglia NLRP3 KO. Furthermore, TAK 242, a specific inhibitor of Toll-like receptor-4, resulted in a significant reduction in NLRP3 and pro-IL-1β in BV2 cells with S1 protein stimulation. These results reveal a distinct mechanism through which the SARS-CoV-2 spike S1 protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses.
认知障碍在新型冠状病毒病 2019（COVID-19）的急性期和后遗症中经常被发现，但其潜在机制尚不清楚。严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的 S1 蛋白可能是 COVID-19 相关认知障碍的一个原因。核苷酸结合域、富含亮氨酸重复家族、pyrin 域包含 3（NLRP3）炎症小体和神经炎症在伴有认知障碍的阿尔茨海默病（AD）中发挥重要作用。然而，它们在 COVID-19 伴有认知障碍中的作用仍不清楚。我们在体外用 S1 蛋白刺激 BV2 细胞，并在体内用 S1 蛋白注射野生型（WT）小鼠、NLRP3 敲除（KO）和小神经胶质 NLRP3 KO 小鼠的海马，以诱导认知障碍。我们使用新物体识别和 Morris 水迷宫测试评估探索性行为作为联想记忆。通过免疫荧光和 Western blot 分析神经炎症，以检测炎症标志物。使用共聚焦显微镜研究 NLRP3 和 S1 蛋白的共定位。我们发现，S1 蛋白注射通过激活 NLRP3 炎症导致认知障碍、神经元丢失和神经炎症，而全身性 NLRP3 KO 和小神经胶质 NLRP3 KO 可减轻这种情况。此外，Toll 样受体 4 的特异性抑制剂 TAK 242 可显著减少 S1 蛋白刺激的 BV2 细胞中 NLRP3 和 pro-IL-1β。这些结果揭示了 SARS-CoV-2 刺突 S1 蛋白促进 NLRP3 炎症小体激活并诱导过度炎症反应的独特机制。
