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Wobus, C. E.

Publications and source records attributed to Wobus, C. E..

2 recordsLinked to original sources
bioRxiv2018

Central carbon metabolism is an intrinsic factor for optimal replication of a norovirus

The metabolic pathways of central carbon metabolism, glycolysis and oxidative phosphorylation (OXPHOS), are important host factors that determine the outcome of viral infections and can therefore be manipulated by some viruses to favor infection. However, mechanisms of metabolic modulation and their effects on viral replication vary widely. Herein, we present the first metabolomics profile of norovirus-infected cells, which revealed increases in glycolysis, OXPHOS, and the pentose phosphate pathway (PPP) during murine norovirus infection. Inhibiting glycolysis with 2-deoxyglucose (2DG) in transformed and primary macrophages revealed that host cell metabolism is an important factor for optimal murine norovirus (MNV) infection. 2DG affected an early stage in the viral life cycle after viral uptake and capsid uncoating, leading to decreased levels of viral protein translation and viral RNA replication. The requirement of central carbon metabolism was specific for MNV (but not astrovirus) infection, independent of the Type I interferon antiviral response, and unlikely to be due to a lack of host cell nucleotide synthesis. MNV infection increased activation of the protein kinase Akt, but not AMPK, two master regulators of cellular metabolism, suggesting Akt signaling may play a role in upregulating central carbon metabolism during norovirus infection. In conclusion, our findings suggest that the metabolic state of target cells is an intrinsic host factor that determines the extent of norovirus replication and implicates metabolism as a virulence determinant. They further implicate cellular metabolism as a novel therapeutic target for norovirus infections and improvements of current human norovirus culture systems.\n\nIMPORTANCEViruses depend on the host cells they infect to provide the machinery and substrates for replication. Host cells are highly dynamic systems that can alter their intracellular environment and metabolic behavior, which may be helpful or inhibitory for an infecting virus. In this study, we show that macrophages, a target cell of murine norovirus (MNV), increase central carbon metabolism upon viral infection, which is important for early steps in MNV infection. Human noroviruses (hNoV) are a major cause of gastroenteritis globally, causing enormous morbidity and economic burden. Currently, no effective antivirals or vaccines exist for hNoV, mainly due to the lack of high efficiency in vitro culture models for their study. Thus, insights gained from the MNV model may reveal aspects of host cell metabolism that can be targeted for improving hNoV cell culture systems and for developing effective antiviral therapies.

microbiology↗
bioRxiv2018

Natural Secretory Immunoglobulins Enhance Norovirus Infection

Secretory immunoglobulins (SIg) are a first line of mucosal defense by the host. They are secreted into the gut lumen via the polymeric immunoglobulin receptor (pIgR) where they bind to antigen and are transported back across the FAE via M cells. Noroviruses are highly prevalent, enteric pathogens that cause significant morbidity, mortality and economic losses worldwide. Murine norovirus (MNV) exploits microfold (M) cells to cross the lymphoid follicle-associated epithelium (FAE) and infect the underlying population of immune cells. However, whether natural, innate SIg can protect against norovirus infection remains unknown. To investigate the role of natural SIg during murine norovirus pathogenesis, we used pIgR-deficient animals, which lack SIg in the intestinal lumen. Contrary to other enteric pathogens, acute MNV replication was significantly reduced in the gastrointestinal tract of pIgR-deficient animals compared to controls, despite increased numbers of dendritic cells, macrophages, and B cells in the Peyers patch, established MNV target cell types. Also, natural SIg did not alter MNV FAE binding or FAE crossing into the lymphoid follicle. Instead, further analysis revealed enhanced baseline levels of the antiviral molecules interferon gamma (IFN{gamma}) and inducible nitric oxide synthase (iNOS) in the small intestine of naive pIgR-deficient animals compared to controls. Removing the microbiota equalized IFN{gamma} and iNOS transcript levels as well as MNV viral loads in germ-free pIgR KO mice compared to germ-free controls. These data are consistent with a model whereby SIg sensing reduces pro-inflammatory, antiviral molecules, which facilitates intestinal homeostasis but thereby promotes MNV infection. In conclusion, these findings demonstrate that natural SIg are not protective during norovirus infection in mice and represent another example of indirect modulation of enteric virus pathogenesis by the microbiota.

microbiology↗