Effect Of The Glycoprotein Content And The Glucose Metabolites On The Pathogenicity Of Rabies Virus

Rabies is a widespread fatal zoonosis with a mortality rate of nearly 100% once the clinical symptoms have developed.Rabies virus(RABV)is the causative agent of rabies.Rabies still threatens most parts of the world,especially the developing country in Asia and Africa.Though the number of people dying of rabies in China has been decreasing year by year,the death number of rabies is still in the forefront of all kinds of infectious diseases.Glycoprotein(G)is critical for the pathogenicity of RABV.LBNSE-dOG with two copies of codon-optimized G gene was constructed.The growth curves of LBNSE-dOG on the mouse source cells were consistent with the parent strains,but the expression level of G protein in the culture medium and the G protein content of the purified viron were enhanced.LBNSE-dOG induced stronger apoptosis than LBNSE-d G and LBNSE did both in vitro and in vivo,resulting in reduced virulence in the mouse brains.Our results demonstrate that LBNSE-dOG enhances the expression of G protein and displays attenuated pathogenicity.In the early study,the survival rate of mice was improved by immunizing with vaccine strain Tri GAS,meanwhile,the glucose metabolism in the brain of mice was also enhanced.This suggests that the influence of RABV G protein expression on pathogenicity may be related to glucose metabolism alteration in the brain.The G protein content in the lab-fixed RABV strain was higher than that in the wild-type RABV strain.In our study,the uptake of glucose was increased in the mouse brains at the late stage with the infection of different lethal RABV strains(lab-attenuated strain CVS-B2 c and wild-type strain DRV-AH08).Extensive studies have identified important roles for lysine acetylaion in the regulation of intermediate metabolism.Besides,the acetyl group donor,acetyl-Co A,is the intermediate connecting glycolysis and tricarboxylic acid cycle(TCA).We speculate that the host may realize the regulation of metabolic pathway through acetylation modification.Thus,the comprehensive analysis of the lysine acetylation and the target analysis of energy-metabolites in the mouse brains infected with different RABV strains were conducted.Total 156 acetylated sites and 115 acetylated proteins were identified as significant differences during RABV infection.Comparing to the DMEM-and CVSinfected mouse brains,the lysine acetylation level of the enzymes of glycolysis and TCA were altered and the enzyme activity were enhanced in DRV-infected mouse brains.The metabolomic analysis revealed the abundant accumulation of oxaloacetate(OAA)in the mouse brains infected with RABV,while CVS led to more OAA accumulation(29.3-fold to mock)in the brains than DRV did(6.9-fold to mock),which could contribute to the enhancement of the metabolic rate in substrate level.Finally,the in vivo test confirmed that the OAA could reduce the excessive inflammation induced by CVS in the mouse brains by inhibiting the JNK and P38phosphorylation.Our study reveals a negative correlation between the content of G protein with the pathogenicity.Comparing the two RABV strains with different G protein expression level,our research provides insight into the different strategies the host adopt to regulate the glucose metabolism for the energy requirement with the infection of different RABV strains and suggests that implementation of OAA could be a potential strategy to prevent neuron damage during RABV infection.