Li Mengyuan, Yuan Hang, Yang Xiaofei, Lei Yingfeng, Lian Jianqi
Department of Infectious Diseases, Tangdu Hospital, Air Force Medical University, Xi'an, 710038, China.
Pathogenic Biology, Medical College of Yan'an University, Yan'an, 716000, China.
Cell Biosci. 2025 Jan 22;15(1):6. doi: 10.1186/s13578-024-01340-3.
Japanese encephalitis (JE) induced by Japanese encephalitis virus (JEV) infection is the most prevalent diagnosed epidemic viral encephalitis globally. The underlying pathological mechanisms remain largely unknown. Given that viruses are obligate intracellular parasites, cellular metabolic reprogramming triggered by viral infection is intricately related to the establishment of infection and progression of disease. Therefore, uncovering and manipulating the metabolic reprogramming that underlies viral infection will help elucidate the pathogenic mechanisms and develop novel therapeutic strategies.
Metabolomics analysis was performed to comprehensively delineate the metabolic profiles in JEV-infected mice brains and neurons. Metabolic flux analysis, quantitative real-time PCR, western blotting and fluorescence immunohistochemistry were utilized to describe detailed glutamine-glutamate metabolic profiles during JEV infection. Exogenous addition of metabolites and associated compounds and RNA interference were employed to manipulate glutamine-glutamate metabolism to clarify its effects on viral replication. The survival rate, severity of neuroinflammation, and levels of viral replication were assessed to determine the efficacy of glutamine supplementation in JEV-challenged mice.
Here, we have delineated a novel perspective on the pathogenesis of JE by identifying an aberrant low flux in glutamine-glutamate metabolism both in vivo and in vitro, which was critical in the establishment of JEV infection and progression of JE. The perturbed glutamine-glutamate metabolism induced neurotransmitter imbalance and created an immune-inhibitory state with increased gamma-aminobutyric acid/glutamate ratio, thus facilitating efficient viral replication both in JEV-infected neurons and the brain of JEV-infected mice. In addition, viral infection restrained the utilization of glutamine via the glutamate-α-ketoglutaric acid axis in neurons, thus avoiding the adverse effects of glutamine oxidation on viral propagation. As the conversion of glutamine to glutamate was inhibited after JEV infection, the metabolism of glutathione (GSH) was simultaneously impaired, exacerbating oxidative stress in JEV-infected neurons and mice brains and promoting the progression of JE. Importantly, the supplementation of glutamine in vivo alleviated the intracranial inflammation and enhanced the survival of JEV-challenged mice.
Altogether, our study highlights an aberrant glutamine-glutamate metabolism during JEV infection and unveils how this facilitates viral replication and promotes JE progression. Manipulation of these metabolic alterations may potentially be exploited to develop therapeutic approaches for JEV infection.
日本脑炎病毒（JEV）感染所致的日本脑炎（JE）是全球最常见的确诊流行性病毒性脑炎。其潜在的病理机制仍 largely 未知。鉴于病毒是专性细胞内寄生虫，病毒感染引发的细胞代谢重编程与感染的建立和疾病进展密切相关。因此，揭示和调控病毒感染背后的代谢重编程将有助于阐明致病机制并开发新的治疗策略。
进行代谢组学分析以全面描绘 JEV 感染小鼠脑和神经元中的代谢谱。利用代谢通量分析、定量实时 PCR、蛋白质印迹和荧光免疫组织化学来描述 JEV 感染期间详细的谷氨酰胺 - 谷氨酸代谢谱。通过外源添加代谢物及相关化合物和 RNA 干扰来调控谷氨酰胺 - 谷氨酸代谢，以阐明其对病毒复制的影响。评估存活率、神经炎症严重程度和病毒复制水平，以确定谷氨酰胺补充对 JEV 攻击小鼠的疗效。
在此，我们通过鉴定体内和体外谷氨酰胺 - 谷氨酸代谢中异常的低通量，描绘了 JE 发病机制的新视角，这对 JEV 感染的建立和 JE 的进展至关重要。受干扰的谷氨酰胺 - 谷氨酸代谢导致神经递质失衡，并产生γ-氨基丁酸/谷氨酸比值升高的免疫抑制状态，从而促进 JEV 感染神经元和 JEV 感染小鼠脑中的病毒高效复制。此外，病毒感染通过谷氨酸 -α-酮戊二酸轴抑制神经元中谷氨酰胺的利用，从而避免谷氨酰胺氧化对病毒传播的不利影响。由于 JEV 感染后谷氨酰胺向谷氨酸的转化受到抑制，谷胱甘肽（GSH）的代谢同时受损，加剧了 JEV 感染神经元和小鼠脑中的氧化应激并促进了 JE 的进展。重要的是，体内补充谷氨酰胺减轻了颅内炎症并提高了 JEV 攻击小鼠的存活率。
总之，我们的研究突出了 JEV 感染期间异常的谷氨酰胺 - 谷氨酸代谢，并揭示了其如何促进病毒复制和推动 JE 进展。对这些代谢改变的调控可能被用于开发 JEV 感染的治疗方法。
