Elucidation of the Roles of Mitochondrial Protein Vdac3 in Metabolic Regulation and Viral Pathogenesis

Our previous studies have indicated that enteroviral infection causes mitochondrial dysfunction. Mitochondria lie at the central hub of metabolism, energy production, redox homeostasis and antiviral signaling. Being the sites for numerous biochemical reactions, mitochondria regulate the abundance of NADH and NADPH, and hence the cellular energetic and redox status. During infection, virus hijacks the mitochondria to meet the metabolic needs for viral replication. The inter-relationship between mitochondria, metabolism and viral pathogenesis is not completely understood. On studying the interactome of enterovirus 71 protein 2B, we found that it binds to mitochondrial protein VDAC3. Voltage-dependent anion channels (VDACs) are known to be involved in transport of metabolites and ions, and regulation of mitochondrial metabolism and redox milieu. In the present project, we will use animal and cellular models to study how changes in VDAC3 expression affect EV71 replication and the outcome of infection. Besides, we will apply protein domain analysis and site directed mutagenesis to define the interacting domains of 2B and VDAC3, and the domains of VDAC3 related to infection. It is postulated that interaction between 2B and VDAC3 can lead to alterations in metabolic pathways and redox metabolism, and to enhanced viral replication. Another aim of this proposal is to apply metabolomics to explore whether altered VDAC3 expression and/or exogenous 2B expression affects metabolic reprogramming in host cells, and to compare such changes in metabolites with those accompanying EV71-infected VDAC3-knockdown/knockout cells. This helps us to delineate which metabolic pathways may be altered by 2B-VDAC3 interaction. We will further use stable isotopes to measure any changes in fluxes of these pathways. These data will be analyzed along with the data on mitochondrial functions and redox parameters. Functional approach will be taken to study the roles of specific metabolic changes in viral pathogenesis. For validation of findings from cellular models, VDAC3 knockout mice will be infected, and examined for changes in pathology, metabolite profiles and mitochondrial functions of affected tissues. Moreover, VDAC3 interacts with proteins that include enzymes. It is hypothesized that the binding of VDAC3 to 2B may alter its interaction with specific enzymes and hence metabolism. In the present project, we will study whether 2B expression changes interaction of VDAC3 with these proteins. Using targeted metabolomic and functional approaches, we will examine if the metabolic pathways in which these enzymes participate are affected by 2B expression. The present study gives us an insight of the roles of VDAC3 in enteroviral pathogenesis. Broadly speaking, the present project will give us a better understanding of the roles of mitochondria, cellular metabolism and redox microenvironment in host-virus interactions. In the era of preventive medicine, this project will pave a new way for prevention and therapeutic intervention of viral infection.

Project ID:PC10901-0302
External Project ID:MOST107-2320-B182-011-MY3