Pyruvate is the end product of glycolysis and transported into the mitochondria for use in the tricarboxylic acid (TCA) cycle. It is also a common additive in cell culture media. We discovered that inclusion of sodium pyruvate in culture media during infection of mouse bone marrow derived macrophages with influenza A virus impaired cytokine production (IL-6, IL-1β, and TNF-α). Sodium pyruvate did not inhibit viral RNA replication. Instead, the addition of sodium pyruvate alters cellular metabolism and diminished mitochondrial reactive oxygen species (ROS) production and lowered immune signaling. Overall, sodium pyruvate affects the immune response produced by macrophages but does not inhibit virus replication.

Influenza A virus (IAV) causes seasonal epidemics annually and pandemics every few decades. Most antiviral treatments used for IAV are only effective if administered during the first 48 h of infection and antiviral resistance is possible. Therapies that can be initiated later during IAV infection and that are less likely to elicit resistance will significantly improve treatment options. Pyruvate, a key metabolite, and an end product of glycolysis, has been studied for many uses, including its anti-inflammatory capabilities. Sodium pyruvate was recently shown by us to decrease inflammasome activation during IAV infection. Here, we investigated sodium pyruvate’s effects on IAV in vivo. We found that nebulizing mice with sodium pyruvate decreased morbidity and weight loss during infection. Additionally, treated mice consumed more chow during infection, indicating improved symptoms. There were notable improvements in pro-inflammatory cytokine production (IL-1β) and lower virus titers on day 7 post-infection in mice treated with sodium pyruvate compared to control animals. As pyruvate acts on the host immune response and metabolic pathways and not directly on the virus, our data demonstrate that sodium pyruvate is a promising treatment option that is safe, effective, and unlikely to elicit antiviral resistance.

Influenza A virus (IAV) causes seasonal epidemics annually and pandemics every few decades. Most antiviral treatments used for IAV are only effective if administered during the first 48 hours of infection and antiviral resistance is possible. Therapies that can be initiated later during IAV infection and that are less likely to elicit resistance will significantly improve treatment options. Pyruvate, a key metabolite, and end product of glycolysis, has been studied for many uses, including its anti-inflammatory capabilities. Sodium pyruvate was recently shown by us to decrease inflammasome activation during IAV infection. Here, we investigated sodium pyruvate’s effects on IAV in vivo. We found that nebulizing mice with sodium pyruvate decreased morbidity and weight loss during infection. Additionally, treated mice consumed more chow during infection indicating improved symptoms. There were notable improvements in pro-inflammatory cytokine production (IL-1β) and lower virus titers on days 7 post-infection in mice treated with sodium pyruvate compared to control animals. As pyruvate acts on the host immune response and metabolic pathways and not directly on the virus, our data demonstrate that sodium pyruvate is a promising treatment option that is safe, effective, and unlikely to elicit antiviral resistance.

Pyruvate is a key metabolite for energy synthesis. After the production of pyruvate through glycolysis, the molecule then gets shuttled into the mitochondria. Once there, it is modified for use in the TCA cycle. While it is a key metabolite for the cell, it has been shown to have anti-inflammatory properties in vitro. Sodium pyruvate has been shown to have effects on metabolic pathways and their influence on the immune response to diseases. Previously we found that infecting mouse bone marrow derived macrophages (BMDM) with influenza A virus (IAV) and treating those macrophages with sodium pyruvate dampened the immune response compared to untreated controls and other infections. We found that subcutaneous injections in vivo, while increasing activity, did not show noticeable differences between placebo and sodium pyruvate treated groups during IAV infection. However, nebulizing sodium pyruvate significantly improved proportional weight loss compared to saline controls. Sodium pyruvate treated groups were found to lose less weight and consume more chow over the course of infection. Nebulizing C57BL/6J mice with sodium pyruvate decreased viral titer and pro-inflammatory cytokines 7 days post-infection as well. Conclusively, nebulizing sodium pyruvate ameliorates IAV infection in vivo.

Pyruvate is a key metabolite for energy synthesis. After the production of pyruvate through glycolysis, the molecule is shuttled into the mitochondria. Once there, it is modified for use in the TCA cycle and the energy derived from pyruvate is eventually converted into ATP. While pyruvate is a key metabolite, it also appears to have anti-inflammatory properties. In models of sterile inflammation, like ischemia, pyruvate limits inflammation. We observed that infecting murine bone marrow derived macrophages (BMDM) with influenza A virus (IAV) and treating those macrophages with sodium pyruvate results in lower inflammasome activation and reactive oxygen species (ROS) production. However, this was specific to IAV infection as inflammasome activation and ROS were not affected by sodium pyruvate during E. coli infection or lipopolysaccharide (LPS) and ATP treatment of BMDMs. Our results show that IAV induces a potent and unique metabolic reprograming of infected cells. The addition of sodium pyruvate facilitates ATP production, which correlates with less mitochondrial damage and reduced inflammasome activation. Thus, pyruvate deserves additional examination as an anti-inflammatory treatment in diseases where mitochondrial metabolic stress is a factor.