Probing the Role of Secondary Lymphoid Tissue Architecture in HIV-1 Associated NLRP3 Inflammasome Signaling

Human immunodeficiency virus type 1 (HIV-1) infection can lead to both acute and chronic states of inflammation in people with HIV (PWH), even in the setting of effective viral suppression with antiretroviral therapy (ART). Dysfunctional and hyperactive inflammation in PWH is associated with an accelerated aging phenotype that results in increased risk for severe sequelae like neurocognitive impairment and atherosclerotic cardiovascular disease. Development of targeted anti-inflammatory therapies capable of synergizing with existing ART regimens to reduce the long-term burden of HIV disease is limited by a gap in knowledge of the specific molecular mechanisms underlying HIV-associated immune activation. Studies of HIV-1 infection in the lymphoid environment have revealed inflammatory signaling distinct from that in the periphery, prompting the need for methods to probe the types of immune cells directly and indirectly impacted by infection as well as the underlying inflammatory signaling pathways. We have developed a human tonsil tissue explant histoculture model of HIV- 1 infection in which intact tonsil tissue blocks preserve the full native architecture, cellular repertoire, and milieu of lymphoid tissue, and therefore many of the associated cell-cell interactions and functions. Intriguingly, unlike in peripheral blood, abortive HIV-1 infection in lymphoid tissues can cause pyroptosis, a highly inflammatory form of programmed cell death mediated by the NLRP3 inflammasome, affecting bystander cells adjacent to HIV-1 infected CD4+ T cells. This proposal seeks to test the overarching hypothesis that the architecture of intact human lymphoid tissue supports the close apposition of HIV-1 infected CD4+ T cells to activate NLRP3 inflammasome signaling and IL-1ß release in bystander myeloid cells. Aim 1 will evaluate how the presence or absence of lymphoid tissue structure affects HIV-1 infection and inflammatory signaling by comparing intact tonsil tissue with dissociated cell suspensions for differences in cell types, gene expression, and cytokine production. Aim 2 will interrogate the spatial and functional relationships within lymphoid tissue that facilitate NLRP3 activation and generate a molecular morphologic atlas of the HIV-exposed tonsil. This innovative approach, combining single-cell sequencing and spatial transcriptomics with an ex vivo human tonsil model of HIV-1 infection, can yield insights into the innate immune mechanisms driving dysfunctional inflammation in PWH. This work will take place within the Icahn School of Medicine at Mount Sinai (ISMMS) in the Mount Sinai Health System. Between the Department of Medicine Division of Infectious Diseases, Department of Immunology and Immunotherapy, and Center for Advanced Genomic Technology, I am supported by over 100,000 ft2 of research programs and an additional 4500 ft2 of institutional core facilities, in addition to over $200 million in scientific computing resources such as the Minerva supercomputer. Together, this fellowship leverages the resources of my institution and the expertise of my sponsor to support my training in four key areas: 1) scientific excellence, 2) mentorship, teaching, leadership, & advocacy, 3) professional development, and 4) clinical skills.