PR001492 (Project)

Description:Metabolic changes of immune cells contribute to both physiological and pathophysiological outcomes of immune reactions. How viruses alter the metabolic states of mucosal T cells and the precise mechanisms underlying the persisting immune dysfunction during chronic viral infections are key questions that have not been fully addressed. Here, by comparing transcriptome and salivary metabolome profiles of the uninfected individuals and people living with HIV (PLWH) on treatment, we found a role of polyamine metabolism in immune perturbations of the oral mucosa of HIV+ patients. Flow cytometry analysis confirmed the higher expression of ornithine decarboxylase (ODC-1) and eukaryotic translation initiation factor 5A (EIF5A), the polyamine metabolism intermediates in CD4+ T cells in PLWH. Mechanistic studies using an in vitro human tonsil organoid infection model revealed that HIV infection of activated T cells also resulted in increased polyamine synthesis, which was dependent on the activities of caspase-1, IL-1ß, and ODC-1. HIV-1 also led to elevated dysfunctional regulatory T cells (TregDys) /Thelper 17 (Th17) cell ratios as well as heightened expression of ODC-1, EIF5A, and hypusinated EIF5A. Blockade of caspase-1, ODC-1, and EIF5A hypusination and not HIF-1? or NLRP3 reversed the frequency of TregDys showing the direct impact of polyamine pathway in Treg dysfunction during HIV-1 infection. The addition of exogenous polyamines increased TregDys percentages independent of HIV-1 infection in vitro. Finally, oral mucosal TregDys/Th17 ratios and CD4 hyperactivation positively correlated with the increases in salivary putrescine levels, which were found to be elevated in the saliva of PLWH. Thus, by revealing the role of aberrantly increased polyamine synthesis during HIV infection, our study unveils a new mechanism by which chronic viral infections could drive distinct T cell effector programs and Treg dysfunction.