Japanese encephalitis virus NS1 and NS1' proteins induce vimentin rearrangement via the CDK1-PLK1 axis to promote viral replication.

The host cytoskeleton plays crucial roles in various stages of virus infection, including viral entry, transport, replication, and release. However, the specific mechanisms by which intermediate filaments are involved in orthoflavivirus infection have not been well understood. In this study, we demonstrate that the Japanese encephalitis virus (JEV) remodels the vimentin network, resulting in the formation of cage-like structures that support viral replication. Mechanistically, JEV NS1 and NS1' proteins induce the translocation of CDK1 from the nucleus to the cytoplasm and interact with it, leading to the phosphorylation of vimentin at Ser56. This phosphorylation event recruits PLK1, which further phosphorylates vimentin at Ser83. Consequently, these phosphorylation modifications convert the typically filamentous vimentin into non-filamentous "particles" or "squiggles." These vimentin "particles" or "squiggles" are then transported retrogradely along microtubules to the endoplasmic reticulum, where they form cage-like structures. Notably, NS1' is more effective than NS1 in triggering the CDK1-PLK1 cascade response. Overall, our study provides new insights into how JEV NS1 and NS1' proteins manipulate the vimentin network to facilitate efficient viral replication. IMPORTANCE: Japanese encephalitis virus (JEV) is a mosquito-borne orthoflavivirus that causes severe encephalitis in humans, particularly in Asia. Despite the availability of a safe and effective vaccine, JEV infection remains a significant public health threat due to limited vaccination coverage. Understanding the interactions between JEV and host proteins is essential for developing more effective antiviral strategies. In this study, we investigated the role of vimentin, an intermediate filament protein, in JEV replication. Our findings reveal that JEV NS1 and NS1' proteins induce vimentin rearrangement, resulting in the formation of cage-like structures that envelop the viral replication factories (RFs), thus facilitating efficient viral replication. Our research highlights the importance of the interplay between the cytoskeleton and orthoflavivirus, suggesting that targeting vimentin could be a promising approach for the development of antiviral strategies to inhibit JEV propagation.

Effect of Bacillus coagulans on maintaining the integrity intestinal mucosal barrier in broilers.

Bacillus coagulans (B. coagulans), a spore-forming bacteria, has been further studied for its high tolerance to extreme environmental stressors and probiotic characteristics. But the modulatory effect of B. coagulans on the intestinal mucosal barrier remains unclear. To investigate the effects of B. coagulans on intestinal mucosal barrier, 1-day-old broiler chickens were orally administrated with 108 CFU/mL B. coagulans for consecutive 42 days. In this study, the body weight, jejunum villus height and crypt depth of broiler chickens were significantly increased after B. coagulans treatment. B. coagulans also increased the contents of total protein (TP) and albumin (ALB) in serum, and reduced the contents of low-density lipoprotein (LDL-C), blood urea nitrogen (BUN) and triglyceride (TG). In addition, B. coagulans improved the intestinal flora, significantly increasing the relative abundance of beneficial bacteria in the intestine. The ability of B. coagulans to enhance innate immunity is observed by the increased number of goblet cells and the decreased mRNA expression of IL-1ß, IL-6, TNF-α, and sIgA content. Moreover, B. coagulans promoted intestinal epithelial proliferation through the Wnt/ß-catenin signaling pathway. This study demonstrated that B. coagulans could maintain the intestinal mucosal barrier by improving the intestinal flora, enhancing innate immunity and promoting intestinal epithelial proliferation.