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Rabies, caused by rabies virus (RABV), is a widespread zoonosis that is nearly 100% fatal. Alteration of the metabolic environment affects viral replication and the immune response during viral infection. In this study, glucose uptake was increased in mouse brains at the late stage of infection with different RABV strains (lab-attenuated CVS strain and wild-type DRV strain). To illustrate the mechanism underlying glucose metabolism alteration, comprehensive analysis of lysine acetylation and target analysis of energy metabolites in mouse brains infected with CVS and DRV strains were performed. A total of 156 acetylated sites and 115 acetylated proteins were identified as significantly different during RABV infection. Compared to CVS- and mock-infected mice, the lysine acetylation levels of glycolysis and tricarboxylic acid (TCA) cycle enzymes were decreased, and enzyme activity was upregulated in DRV-infected mouse brains. Metabolomic analysis revealed high levels of oxaloacetate (OAA) in RABV-infected mouse brains. Specifically, the OAA level in CVS-infected mouse brains was higher than that in DRV-infected mouse brains, which contributed to the enhancement of the metabolic rate at the substrate level. Finally, we confirmed that OAA could reduce excessive neuroinflammation in CVSinfected mouse brains by inhibiting JNK and P38 phosphorylation. Taken together, this study provides fresh insight into the different strategies the host adapts to regulate glucose metabolism for energy requirements after different RABV strain infections and suggests that OAA treatment is a strategy to prevent neural damage during RABV infection. IMPORTANCE Both viral replication and the host immune response are highly energy dependent. It is important to understand how the rabies virus affects energy metabolism in the brain. Glucose is the direct energy source for cell metabolism. Previous studies have revealed that there is some association between acetylation and metabolic processes. In this study, comprehensive protein acetylation and glucose metabolism analysis were conducted to compare glucose metabolism in mouse brains infected with different RABV strains. Our study demonstrates that the regulation of enzyme activity by acetylation and OAA accumulation at the substrate level are two strategies for the host to respond to energy requirements after RABV infection. Our study also indicates the role OAA could play in neuronal protection by suppressing excessive neuroinflammation. [ABSTRACT FROM AUTHOR]

Coronaviruses pose serious health threats to humans and other animals. Understanding the mechanisms of their replication has important implications for global health and economic stability. Nonstructural protein 9 (nsp9) is an essential RNA binding protein for coronavirus replication. However, the mechanisms of the dimerization and nucleic acid binding of nsp9 remain elusive. Here, we report four crystal structures, including wild-type porcine delta coronavirus (PDCoV) nsp9, PDCoV nsp9-ΔN7 (N-terminal 7 amino acids deleted), wild-type porcine epidemic diarrhea virus (PEDV) nsp9, and PEDV nsp9-C59A mutant. These structures reveal the diverse dimerization forms of coronavirus nsp9. We first found that the N-finger of nsp9 from PDCoV plays a critical role in dimerization. Meanwhile, PEDV nsp9 is distinguished by the presence of a disulfide bond in the dimer interface. Interestingly, size exclusion chromatography and analytical ultracentrifugation analyses indicate that the PDCoV nsp9-ΔN7 and PEDV nsp9-C59A mutants are monomeric in solution. In addition, electrophoretic mobility shift assays and microscale thermophoresis analysis indicate that the monomeric forms of PDCoV nsp9 and PEDV nsp9 still have nucleic acid binding affinity, although it is lower than that of the wild type. Our results show that the diverse dimerization forms of coronavirus nsp9 proteins enhance their nucleic acid binding affinity. IMPORTANCE Coronaviruses cause widespread respiratory, gastrointestinal, and central nervous system diseases in humans and other animals, threatening human health and causing economic loss. Coronavirus nsp9, a member of the replication complex, is an important RNA binding subunit in the RNA-synthesizing machinery of all coronaviruses. However, the mechanisms of the dimerization and nucleic acid binding of nsp9 remain elusive. In this study we determined the nsp9 crystal structures of PDCoV and PEDV. We first found that the N-finger of nsp9 from PDCoV plays a critical role in dimerization. Meanwhile, PEDV nsp9 is distinguished by the presence of a disulfide bond in the dimer interface. This study provides a structural and functional basis for understanding the mechanism of dimerization and shows that the diverse dimerization modes of coronavirus nsp9 proteins enhance their nucleic acid binding affinity. Importantly, these findings may provide a new insight for antiviral drug development. [ABSTRACT FROM AUTHOR]