Anti-Inflammatory Viral Proteins to Treat Sepsis

This proposal looks to improve the health and well-being of the active military, Veterans, and beneficiaries by specifically addressing the Fiscal Year 2019 (FY19) Peer Reviewed Medical Research Program (PRMRP) topic area: Emerging Infectious Diseases. By addressing the problems associated with treatment of viral sepsis, this program targets the FY19 PRMRP Areas of Encouragement: defining the immune correlates of protection for emerging infectious disease, and understanding viral sepsis. Viral sepsis is a preventable cause of morbidity and mortality for the U.S. military. Sepsis is caused by a dysregulation of the host response to a pathogen. One-third of those who develop sepsis die and those that survive are left with chronic debilitating conditions. While a large majority of cases of sepsis are caused by bacterial pathogens, over 30 percent of sepsis cases are not bacterial in origin and currently antibiotics are the only treatment for sepsis. Emerging infectious diseases including dengue (DENV), Murray Valley encephalitis (MVE), Japanese encephalitis virus (JEV), Venezuelan encephalitis (VEE), and influenza (IAV) are all known to cause viral sepsis. One factor often overlooked in sepsis is that the diseases have striking similarities. By focusing on the similarities between diseases, this proposal aims to prevent the rapid onset of inflammation associated with sepsis independent of a disease diagnosis. Rationale: The viral proteins encoded by poxviruses have evolved over millions of years to control host inflammation during infection. For example, chemokine response modifier (Crm) proteins are a series of proteins encoded by several poxviruses that inhibit immune function by blocking chemokine and cytokine functions. Another poxvirus protein that has a strong anti-inflammatory history is the vaccinia virus complement control protein (VCP). VCP is part of a group of complement regulatory proteins; it is secreted and functions by binding of C3 and C5b to inhibit the classic and alternative complement pathways. The polyfunctionality of these virally encoded proteins make them effective inflammatory inhibitors, and they are an untapped resource for controlling sepsis disease. The goal is to use viral cytokine and/or complement suppressors to get people past the crisis point that occurs with sepsis in order to give time for disease diagnosis to occur and effective treatments to be administered. Innovation: This discovery proposal utilizes an existing model to test CrmD and VCP for the control of viral sepsis. This proposal uses virally encoded anti-inflammatories in a high-risk, high-reward hypothesis-driven strategy. The innovations within this proposal are: (1) the exploitation of virally encoded anti-inflammatories to treat sepsis, (2) the proposed use of novel anti-inflammatories for sepsis treatment, (3) the availability of a tractable animal model that mimics the symptoms of viral sepsis, and (4) the ability to treat sepsis independent of the instigating pathogen. Specific Aims Aim 1: Determine therapeutic window of chemokine response modifier D (CrmD) in a murine DENV model of sepsis. The hypothesis to be tested is that Poxvirus encoded CrmD will reduce the DENV disease through reduction of inflammatory cytokines. This hypothesis will be challenged by treating DENV-infected LysM Cre Ifnar1l/f mice with CrmD at different time points after infection. Efficacy of the CrmD treatment will be determined through measurements of weight loss, clinical score, and survival as well as viral tiers, cytokine levels, chemistry, and hematology to assess the improvement in disease outcome following therapeutic treatment. To identify if the cells making the cytokine are also the infected cells, we will single cell sort cells from DENV-infected mice and using qRT-PCR techniques identify the number of cells infected with DENV2 and determine if those cells are making cytokine. Aim 2: Test the vaccinia virus complement control protein (VCP) in the murine DENV model of sepsis. The hypothesis to be tested is that targeting complement activation through administration of VCP will reduce symptoms of disease associated with viral sepsis in our model. This hypothesis will be challenged using similar procedures as in Aim 1 with additional studies to address complement activation and possible VCP toxicity. Less