| Japanese encephalitis virus(JEV), belongs to the family Flaviviridae, genus Flavivirus.JEV genomics a 11 kb positive-sense RNA.There are no special efficient treatment for encephalitis B.Formulating JEV pathogenic mechanism at the molecular level and developing special effective JEV treatment is the hot spot and front of JEV research in recent years.Protein folding is strategically important to cellular function. Secreted,membrane-bound and organelle-targeted proteins are typically processed and folded in the endoplasmic reticulum(ER) in eukaryotes. Normally, cells ensure that proteins are correctly folded using a combination of molecular chaperones, foldases, and lectins. If unfolded or misfolded proteins continue to accumulate, eukaryotes induce the unfolded protein response(UPR).In mammalian cells, UPR is a complex signaling program mediated by three ER transmembrane receptors: activating transcription factor 6(ATF6),inositol requiring kinase 1(IRE1), and double-stranded RNA-activated protein kinase(PKR)-like endoplasmic reticulum kinase(PERK). UPR performs three functions,adaptation, alarm, and apoptosis. During adaptation, the UPR tries to reestablish folding homeostasis by inducing the expression of chaperones that enhance protein folding.Simultaneously, translation is globally attenuated to reduce the ER folding load while the degradation of unfolded proteins is increased. If these steps fail, the UPR induces a cellular alarm and apoptosis program. The alarm phase involves several signal transduction events,ultimately leading to the removal of the translational block and the down-regulation of the expression and activity of pro-survival factors such as the B-cell lymphoma 2(Bcl2)protein. After the alarm phase, cells can undergo apoptosis, although ER stress can also initiate autophagy. Thus, ER folding homeostasis strongly influences physiology.JEV strain SA14-14-2 infection in BHK-21 cell striggered ER stress by elevating mRNA levels of GRP78 and ATF4, increasing protein levels of GRP78 and CHOP, and inducing XBP1 m RNA and ATF6 protein splicing. Cytopathic effect and viability derease in BHK-21 cells by SA14-14-2 infection and ER stress inducer tunicamycin were also observed. At the same time, we observe both JEV and tunicamycin up regulate mRNA levels of a large number of ER correlation protein such as GRP78 and AFT4 through RNA-seq technology. In the condition of these inhibitors had no effect on virus replication,both IRE1 inhibitor 3,5-Dibromosalicylaldehyde and JNK inhibitor SP600125 inhibited significantly SA14-14-2-induced apoptosis,SA14-14-2 and ER stress inducer tunicamycin caused the apoptosis of BHK-21 cells.For the first time, we revealed that JEV induced apoptosis of BHK-21 cells by the activation of IRE1 and JNK. These findings provide important insights into the role of ER Stress response in JEV-associated disease and specific drug target against Japanese encephalitis. |
