Superoxide Production by NADPH Oxidase Intensifies Macrophage Antiviral Responses during Diabetogenic Coxsackievirus Infection

Abstract

Coxsackievirus B infections are suspected environmental triggers of type 1 diabetes (T1D) and macrophage antiviral responses may provide a link to virus-induced T1D. We previously demonstrated an important role for NADPH oxidase (NOX)–derived superoxide production during T1D pathogenesis, as NOX-deficient NOD mice (NOD.Ncf1m1J) were protected against T1D due, in part, to impaired proinflammatory TLR signaling in NOD.Ncf1m1J macrophages. Therefore, we hypothesized that loss of NOX-derived superoxide would dampen diabetogenic antiviral macrophage responses and protect from virus-induced diabetes. Upon infection with a suspected diabetogenic virus, Coxsackievirus B3 (CB3), NOD.Ncf1m1J mice remained resistant to virus-induced autoimmune diabetes. A concomitant decrease in circulating inflammatory chemokines, blunted antiviral gene signature within the pancreas, and reduced proinflammatory M1 macrophage responses were observed. Importantly, exogenous superoxide addition to CB3-infected NOD.Ncf1m1J bone marrow–derived macrophages rescued the inflammatory antiviral M1 macrophage response, revealing reduction-oxidation–dependent mechanisms of signal transducer and activator of transcription 1 signaling and dsRNA viral sensors in macrophages. We report that superoxide production following CB3 infection may exacerbate pancreatic β cell destruction in T1D by influencing proinflammatory M1 macrophage responses, and mechanistically linking oxidative stress, inflammation, and diabetogenic virus infections.