The focus of the proposed study is innate immune activation by HIV-1 infection. Innate inflammation is caused by HIV-1 replication and/or microbial toll-like receptor [TLR] ligands (e.g. lipopolysaccharide) that leak from the intestinal lumen into the circulation (microbial translocation). The consequences of HIV-1-associated innate inflammation remain unclear, although enhanced HIV-1 replication and a spectrum of sequelae including HIV-associated neurocognitive impairment, endothelial dysfunction, cardiovascular disease, cancer, or coagulopathy are associated with immune activation. The long-term objective is to improve treatment of HIV-1-associated innate inflammation by developing novel approaches to target immune activation. I hypothesize that HIV-1 and TLR ligands cooperatively mediate classical macrophage activation through novel signaling networks that can be targeted for inhibition by HIV-1 protease inhibitors. HIV-1 augments lipopolysaccharide-induced classical activation of macrophages via a priming effect phenotypically similar to interferon-γpriming, although with greater molecular complexity.
Aim 1 will determine the molecular mechanism of HIV-1 induced priming of human macrophages using a systems biology approach. Identification of molecular bioprofiles, candidate genes/proteins, or cellular processes that contribute to HIV-1- induced macrophage activation will be the first step in a long-term approach to study the immunopathogenesis of HIV-1 infection.
Aim 1 is designed to lay the groundwork for future studies that investigate HIV-1-induced innate immune activation in vivo. Findings will also provide novel insights into the HIV-1/host interaction and will provide the basis for studies of HIV-1 replication/persistence in macrophages.
Aim 2 will investigate anti-inflammatory properties of two HIV-1 protease inhibitor drugs nelfinavir and tipranavir, independent of anti-viral effects. Preliminary data demonstrates that nelfinavir and tipranavir, unique from other HIV-1 protease inhibitors, exert anti-inflammatory effects upon macrophages.
Aim 2 will determine the molecular basis of inhibition with the long term goal of identifying a specific cellular protein target(s) of the drugs, potentially a host cell protease(s). Here innovative proteomics approaches will be applied to interrogate cell signaling events downstream of the primary lipopolysaccharide receptor TLR4. In this regard, nelfinavir and tipranavir will be evaluated not only as potential therapeutic agents, but also as investigative tools for dissecting inflammatory cell signaling events related to HIV-1 infection. Outcomes of this study will advance understanding of HIV-1 immune pathogenesis and lead to improved treatments/interventions for inflammatory complications of HIV-1 infection. The study is poised to achieve not only scientific goals, but also goals for my independent career development. Achieving the objectives of the Specific Aims will lay the groundwork for two NIH R01 applications and enhance institutional commitment to my research program.
HIV-1 is the causative agent of acquired immune deficiency syndrome [AIDS];however emerging evidence implicates HIV-1 in a broader illness that includes systemic immune system activation. This study will determine the mechanism of HIV-1-induced macrophage activation while also developing novel approaches to suppress harmful inflammation. The findings of this study will directly impact human health by bringing about changes to current HIV-1 therapy regimens to include drugs that treat inflammation while still striving to suppress HIV-1 replication. The scientific goals of the proposed study support my career goals by providing a basis for long-term funding and a pathway to independence.
|Appelberg, K Sofia; Wallet, Mark A; Taylor, Jared P et al. (2017) HIV-1 Infection Primes Macrophages Through STAT Signaling to Promote Enhanced Inflammation and Viral Replication. AIDS Res Hum Retroviruses 33:690-702|
|Wallet, Mark A; Buford, Thomas W; Joseph, Anna-Maria et al. (2015) Increased inflammation but similar physical composition and function in older-aged, HIV-1 infected subjects. BMC Immunol 16:43|
|Wallet, Mark A; Reist, Caroline M; Williams, Julie C et al. (2012) The HIV-1 protease inhibitor nelfinavir activates PP2 and inhibits MAPK signaling in macrophages: a pathway to reduce inflammation. J Leukoc Biol 92:795-805|