CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

distinct transcriptomic differences between HIV+ and HIV- T cells. Across all T cells (gut and blood), the HIV+ cells exhibited elevated expression of a set of cytokines including IL-2, IL-21 and CCL20, while the HIV-regulating long non-coding RNA MALAT1 was downregulated. NFKBID and JARID, which encode proteins that repress HIV expression, were also upregulated in HIV+ T cells. Within the HIV+ gut T cells, MTRNR2L1, a negative regulator of apoptosis, was upregulated, suggesting a mechanism by which GI resident HIV+ cells can persist. Conclusions: By identifying molecular mechanisms of differential transcriptional regulation in GI tissue resident T cells, we generate testable hypotheses that may lead to a better understanding of HIV latency and persistence. HIV Transcriptional Regulation in the CNS of ART-Suppressed People With HIV Janna Jamal Eddine 1 , Emily Chalmers 1 , Jingling Zhou 1 , Sarah Byrnes 1 , Sushama Telwatte 2 , Bruce Brew 3 , Michael Roche 2 , Thomas Angelovich 1 , Melissa Churchill 4 1 RMIT University, Melbourne, Australia, 2 Peter Doherty Institute for Infection and Immunity, Melbourne, Australia, 3 St Vincent's Hospital, Sydney, Australia, 4 Royal Melbourne Institute of Technology, Melbourne, Australia Background: We and others have previously demonstrated that intact, transcriptionally competent HIV genomes persist within the brain of virally suppressed people with HIV (PWH). Long terminal repeats (LTRs) isolated from the brain of non-virally suppressed PWH are genetically distinct from those isolated in matched peripheral tissue and have a reduced responsiveness to select latency reversing agents (LRAs) in brain cell lines. Whether promotors isolated from the brain of virally suppressed individuals are functional, genetically distinct and responsive to LRAs is unclear. Methods: Autopsy frontal cortex brain tissue and matched peripheral tissue (spleen, lymph node, gut) from virally suppressed PWH (n=6; undetectable plasma viral load for a median of 3.41 years) were provided by the National NeuroAIDS Tissue Consortium. HIV LTRs were isolated using triple nested single genome amplification. Phylogenetic compartmentalisation and transcription factor binding site analyses was performed. Transcriptional activity of isolated LTRs transfected into astrocyte and microglia cell lines was assessed in the presence and absence of LRAs. Results: 66 LTR sequences, including 45 unique sequences, were isolated from the brain and matched peripheral tissue of 6 virally suppressed PWH. In contrast to our previous findings in non-virally suppressed PWH, phylogenetic compartmentalisation was not observed between brain and peripheral sequences in virally suppressed PWH. Identical LTR sequences were isolated from frontal cortex brain, gut and lymph node of two participants. Most of the sequences isolated from the frontal cortex of virally suppressed PWH retained intact core promotor regions (TATA, Sp1, NF-κB). Some promotors had additional sites, including Sp1 and TCF-α. Hypermutated sequences within frontal cortex and gut tissue were also isolated. Promoters were demonstrated to be active under basal and tat-activated conditions, with activities heterogenous across the compartments analysed. Conclusions: Promotors isolated from virally suppressed PWH appear to be regulated differently to those isolated from the CNS of non-virally suppressed PWH. Compartmentalization of LTR sequences characteristic of non-virally suppressed promotors was not observed in LTR sequence isolated from virally suppressed PWH. Association of CSF Viral Compartmentalization and Macrophage Tropism With Neurosymptomatic HIV Laura P. Kincer 1 , Sarah B. Joseph 1 , Natalie M. Bowman 1 , Chris Evans 1 , Alyssa Vecchio 1 , Ameet Dravid 2 , Serena Spudich 3 , Magnus Gisslén 4 , Prema Menezes 1 , Joseph J. Eron 1 , Richard W. Price 5 , Ronald I. Swanstrom 6 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 2 Poona Hospital and Research Centre, Pune, India, 3 Yale University, New Haven, CT, USA, 4 Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden, 5 University of California San Francisco, San Francisco, CA, USA, 6 CIDRZ / University of North Carolina, Chapel Hill, NC, USA Background: HIV-1 can be detected in cerebrospinal fluid (CSF) throughout untreated infection but it is unknown how often this is due to local replication in the CNS. In people with HIV-associated dementia (HAD), local replication can generate genetically distinct viral populations in the CNS (compartmentalized) with the unique ability to efficiently infect myeloid lineage cells (macrophage- or M-tropic; see panel A). Little is known about the frequency of

compartmentalized and/or M-tropic HIV-1 in the CNS of people with HIV (PWH) who are neuroasymptomatic or have less severe symptoms. Methods: Partial HIV-1 env genes were sequenced from viral RNA in plasma and CSF samples collected from a cross-sectional cohort of ART-naïve PWH (N=109). For a subset of PWH (N=45), full-length env genes were also generated and analyzed for the ability to efficiently enter cells expressing a low CD4 density (M tropism); distinguishing them from T-tropic HIV-1 which requires high CD4. Phylogenetic analyses identified compartmentalized viral populations in CSF and a modified CSF viral load was calculated to represent the amount of virus produced by replication in the CNS (CSF compartmentalized viral load, CCVL). Inflammatory biomarkers were measured in plasma and CSF. Standardized questionnaires were used to determine if PWH were neurosymptomatic (NS) or neuroasymptomatic. Results: In PWH who were NS (53%), CSF HIV-1 RNA was higher (p<0.01), but plasma HIV-1 RNA, CD4+ T cell count, nadir CD4+ T cell count, and CSF WBC count were similar. CSF compartmentalization was more common in PWH who were NS (44% vs 16%, p<0.01), but was detected in both groups (panel B). Overall, compartmentalization (48% vs 18%, p<0.01) and M tropism (85% vs 38%, p=0.02) were more frequent when blood CD4+ T cells were <200/ml. M tropism was only detected with compartmentalization (62% vs 0%, p<0.01). Increasing CCVL was correlated with greater CSF neopterin, NFL, IP10, MMP9, sCD14 and sCD163 (p<0.05). Conclusions: In this ART-naive cohort, compartmentalized HIV-1 replication in the CNS was more common in participants who were neurosymptomatic, but also occurred in the absence of symptoms and in PWH lacking severe immunosuppression. Compartmentalized viral replication in either myeloid-lineage or T cells in the CNS associates with active brain injury and inflammation. Longitudinal studies are needed to determine whether neuroasymptomatic individuals with viral replication in the CNS are at risk of developing neurologic symptoms over time. The figure, table, or graphic for this abstract has been removed. Humanized Glia Mice Show HIV-Induced Behavioral, Neuro, and Metabolic Changes as in Clinical Disease Amanda Fernandes, Ed Makarov, Matthew Thiele, Yutong Liu, Mystera Samuelson, Santhi Gorantla University of Nebraska Medical Center, Omaha, NE, USA Background: Effective ART has lessened the severity but not the frequency of HAND, defined as a spectrum of cognitive, mood, and/or motor deficits affecting the quality of life of PLWH. We recently developed a novel humanized glial mouse reconstituted with the human immune system and glia to study HAND pathology and behavioral phenotype during ART suppressed HIV-infection, to understand the human disease. Methods: Humanized glia mice were infected with HIV-1 ADA at 20w age and treated with ART. Magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) were performed to measure brain metabolic and structural abnormalities. Corresponding neuropathology was analyzed using immunofluorescence. Mood disorders like depression and cognitive deficits in memory and learning were analyzed by sucrose anhedonia test and novel object recognition test. Uninfected, HIV-infected and HIV+ART mice were used in the study (n=6/group). Results: DTI results showed changes in fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the whisker barrel (FA p=0.02; ADC p=0.02), frontal cortex (FA p<0.001), and corpus callosum (ADC p=0.02) with HIV infection and ART suppression demonstrating altered white matter integrity in the brain. This was further co-represented in neuropathological analysis, where demyelination was significant in the cc and cerebellum (p<0.0001). MRS analysis yielded a significant increase in the concentration of different metabolites like phosphocholine (p<0.0001), choline (p<0.0001), and glutamine (p=0.02) in the hippocampus as well as a significant decrease in glucose levels (p=0.0047) and altered myoinositol levels (p=0.0047) in the cortex of HIV infected and ART-treated mice which could in turn lead to increased depression, memory loss and altered astrocytic function as observed in human patients. This was confirmed by both neuropathology and behavior analysis, where a significant decrease in sucrose preference as a measure of anhedonia (p=0.0039), recognition index for memory (p<0.05), and increased astrocytic activation (p<0.05) was observed in the brains of infected mice.

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