Bohara Vijay Singh, Deshmukh Atharva, Kumar Sachin
Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India.
J Gen Virol. 2025 Sep;106(9). doi: 10.1099/jgv.0.002140.
Japanese encephalitis is a neuroinflammatory condition caused by the Japanese encephalitis virus (JEV). Pyruvate kinase muscle isozyme M2 (PKM2) is a key modulator of glucose metabolism. The role of PKM2 in the autoimmune response and inflammation is now increasingly being acknowledged. However, its role in modulating virus replication has not been explored. In the current study, we have explored the role of PKM2 in JEV replication. Our results show that endogenous PKM2 expression is significantly upregulated in JEV-infected mouse neuroblastoma cells. Moreover, overexpression and knockdown studies substantiate the negative effect of PKM2 on JEV replication. Additionally, JEV infection induced signal transducers and activators of transcription 3 (STAT3) activation in the infected neuronal cells. Overexpression of PKM2 enhanced STAT3 activation, while its downregulation reduced STAT3 activation in the JEV-infected neuronal cells. The results suggested that the overexpression of PKM2 exhibited elevated levels of TNF- and IL-1, whereas the downregulation of PKM2 decreased their expression. The studies revealed the potential interaction between PKM2 and non-structural protein 1 (NS1), which was subsequently validated by co-immunoprecipitation assay. The microscopic studies also unveiled the cellular co-localization of PKM2 and NS1 in the endoplasmic reticulum of infected cells. Altogether, these findings indicate that PKM2 negatively regulates JEV replication by inducing the expression of proinflammatory cytokines such as TNF- and IL-1. The study also establishes PKM2 as a binding partner of the NS1 protein. Thus, the study paves the path towards understanding the multifaceted role of PKM2 in JEV pathology.
日本脑炎是一种由日本脑炎病毒（JEV）引起的神经炎症性疾病。丙酮酸激酶肌肉同工酶M2（PKM2）是葡萄糖代谢的关键调节因子。PKM2在自身免疫反应和炎症中的作用如今越来越受到认可。然而，其在调节病毒复制方面的作用尚未得到探索。在当前的研究中，我们探讨了PKM2在JEV复制中的作用。我们的结果表明，在JEV感染的小鼠神经母细胞瘤细胞中，内源性PKM2表达显著上调。此外，过表达和敲低研究证实了PKM2对JEV复制的负面影响。此外，JEV感染在受感染的神经元细胞中诱导了信号转导和转录激活因子3（STAT3）的激活。PKM2的过表达增强了STAT3的激活，而其下调则降低了JEV感染的神经元细胞中STAT3的激活。结果表明，PKM2的过表达使肿瘤坏死因子和白细胞介素-1水平升高，而PKM2的下调则降低了它们的表达。这些研究揭示了PKM2与非结构蛋白1（NS1）之间的潜在相互作用，随后通过免疫共沉淀试验进行了验证。显微镜研究还揭示了PKM2和NS1在受感染细胞内质网中的细胞共定位。总之，这些发现表明，PKM2通过诱导肿瘤坏死因子和白细胞介素-1等促炎细胞因子的表达来负向调节JEV复制。该研究还确定PKM2是NS1蛋白的结合伴侣。因此，该研究为理解PKM2在JEV病理学中的多方面作用铺平了道路。
