CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

intestinal biological aging and whether microbial dysbiosis and translocation contribute to aging in PWH on ART. Methods: Colon and ileal biopsies, blood, and stool were collected from 25 PWH on ART (viral load <50 copies/ml) and 23 age, sex, and ethnicity matched HIV-negative controls. Accelerated biological aging in colon, ileum, and blood was assessed by regressing biological age estimated by several epigenetic aging clocks (Horvath1, Horvath2, Hannum, PhenoAge, GrimAge, and DunedinPACE) against chronological age. Intestinal integrity was assessed by immunofluorescence staining for tight junction proteins (ZO1, occludin). Markers of microbial translocation (e.g., LBP) and inflammation were measured by ELISA/multiplex arrays. Microbiota profiles of stool, ileum, and colon were determined via 16S rRNA sequencing, and metabolic analyses of plasma and stool were conducted using mass spectrometry. Results: Despite similar chronological age (Fig. 1A), PWH exhibited accelerated biological aging of the ileum, colon, and blood. Colon and ileum from PWH showed reduced tight junction proteins and increased microbial translocation, significantly associated with accelerated biological aging and higher inflammation (P<0.05). Putative pro-inflammatory bacteria like Catenibacterium and Prevotella 2/9 were enriched in PWH, correlating with accelerated aging (FDR<10%). Conversely, short-chain-fatty-acid producing and anti-inflammatory bacterial genera, like Subdoligranulum and Erysipelotrichaceae UCG-003 were depleted in PWH, correlating with decelerated aging. Correlation networks revealed associations between specific microbial genera in the colon and ileum (not shown) with accelerated aging, enrichment of pro- inflammatory microbial-related metabolites, and depletion of anti-inflammatory metabolites (P<0.05). Conclusion: Distinct microbial profiles are linked to intestinal and systemic biological aging in PWH on ART. Further research is needed to understand the mechanisms connecting microbial dysbiosis/translocation to intestinal and systemic biological aging in PWH and to develop preventive strategies. The figure, table, or graphic for this abstract has been removed. Deep Metabolic Profiling for Tissue-Specific Responses Against SARS-CoV-2 Variants in Hamster Models Urvinder Kaur Sardarni 1 , Anoop Ambikan 2 , Arpan Acharya 1 , Samuel D. Johnson 1 , Rajesh Rajaiah 1 , Kabita Pandey 1 , Ujjwal Neogi 2 , Siddappa N. Byrareddy 1 1 University of Nebraska Medical Center, Omaha, NE, USA, 2 Karolinska Institute, Stockholm, Sweden Background: While most people recover from acute COVID-19, a significant percentage experience long-term health issues known as post-acute sequelae of SARS-CoV-2 infection (PASC). The underlying host tissue response during acute infection might contribute to long-term effects in people with PASC. To understand this, we investigated the host-tissue responses of SARS-CoV-2 variants using the hamster model. Methods: Syrian golden hamsters (SGHs) were infected with the delta and omicron variant, and uninfected SGHs were used as controls. The hamsters were euthanized four days post-infection, plasma and tissue samples from the lung, brain, heart and kidney were collected to analyse SARS-CoV-2 viral load and untargeted metabolomics. Results: Compared to omicron-infected SGHs, delta-infected SGHs had a higher viral load in lungs (p=0.02), heart (p=0.009), brain (p=0.019), and plasma (p=0007). However, viral load in the kidney of delta- and omicron- infected SGHs did not differ significantly. Principal component analysis (PCA) identified distinct brain metabolite profiles, while showing no disparity in heart metabolites between three groups. Kidney metabolites in infected SGHs differed from naïve ones, and plasma metabolites in omicron-infected and naïve SGHs were distinct from delta-infected SGHs. Detailed investigation of individual metabolites showed the varied effect of delta and omicron variants across multiple tissues. Delta variant infection led to differential regulation of 46, 34, 60, 165, and 37 metabolites, whereas omicron variant infection resulted in 21, 112, 67, 160 and 4 differentially regulated metabolites in lung, brain, heart, kidney and plasma respectively. In the brain and heart, major distinctions were observed in amino acids, with arginine, aspartate, methionine, proline, and tyrosine levels being higher in omicron-infected SGHs compared to those infected with the delta variant suggesting the dysregulation of amino acid biosynthesis/metabolism, nucleotide metabolism and energy metabolism pathways. Conclusion: Our findings indicate that SARS-CoV-2 mediated tissue insult leads to altered host metabolites during acute infection in a strain specific manner.

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Bacteria-Induced Granzyme B Contributes to HIV-1-Mediated Gut CD4 T-Cell Depletion Ex Vivo Kaylee Mickens , Stephanie M. Dillon, Kejun Guo, Ashley Thompson, Bradley S. Barrett, Mario L. Santiago, Cara C. Wilson University of Colorado Anschutz Medical Campus, Aurora, CO, USA Background: The gastrointestinal (GI) tract is a major site for early, massive, and persistent CD4 T cell depletion following acute HIV-1 infection. The mechanisms driving this profound death of gut CD4 T cells remain poorly understood. Among persons with HIV-1 (PWH), a disrupted epithelial barrier results in the translocation of bacteria from the gut lumen to the underlying lamina propria (LP) and systemic circulation. We reported that ex vivo exposure of LP mononuclear cells (LPMC) to enteric bacteria augmented HIV-1-mediated gut CD4 T cell death, shifting the death mechanism from pyroptosis to apoptosis. Microbial exposure of gut CD4 T cells ex vivo upregulated granzyme B (GZB) – an enzyme that facilitates target cell killing by cytotoxic T/NK cells via apoptosis. GZB+ CD4 T cells were detected at higher frequencies in colon biopsies of PWH compared to uninfected controls, despite lower overall CD4 T cell frequencies. Methods: To test if GZB plays a critical role in HIV-1-mediated gut CD4 T cell death, LPMC (n=6 donors) were infected with Transmitter/Founder (TF) HIV-1 (CH040) or mock then exposed to bacterial lysate (Escherichia coli) in the presence/absence of a specific GZB inhibitor, Z-AAD-CMK. 4dpi LPMC were collected and GZB expression, infection (HIV-1 p24), apoptosis (AnnexinV, viability dye/AqVi), and number of CD4 T cells were determined by flow cytometry. OX40 and TNFR2 expression were assessed by flow cytometry. Results: Higher levels of TF HIV-1 infection were observed in GZB+ versus GZB- CD4 T cells (3-fold, p=0.003). GZB+ CD4 T cells showed 1.56-fold higher levels of apoptosis markers (AqVi- AnnexinV+) compared to GZB- cells (p=0.007). TF HIV-1 infection led to substantial CD4 T cell death compared to mock – on average 44% of CD4 T cells depleted in TF HIV-1 infected cultures (p=0.01). Z-AAD-CMK inhibited GZB activity in E. coli-stimulated CD4 T cells by 64%; GZB inhibition rescued CD4 T cells from HIV-1-mediated death (16% vs 44% depletion; p=0.02). HIV-1-infected GZB+ CD4 T cells that survive to 4dpi showed higher expression of anti-apoptotic factors OX40 and TNFR2 compared to GZB- cells (p<0.05). Conclusion: Our findings suggest that bacteria-mediated GZB induction may be a mechanism contributing to massive CD4 T cell death in the GI tract during acute HIV-1 infection. The induction of anti-apoptotic factors in GZB+ CD4 T cells that survive in vitro HIV-1 infection raise the possibility that surviving GZB+ CD4 T cells in the gut may serve as a significant HIV-1 reservoir. Distinct Intestinal Microbial Signatures Linked to Accelerated Biological Aging in People With HIV Shalini Singh 1 , Leila B. Giron 1 , Maliha W. Shaikh 2 , Shivanjali Shankaran 2 , Phillip A. Engen 2 , Zlata R. Bogin 2 , Simona A. Bambi 2 , Aaron Goldman 1 , Toshitha Kannan 1 , Ceylan E. Tanes 3 , Kyle Bittinger 3 , Alan Landay 2 , Michael J. Corley 4 , Ali Keshavarzian 2 , Mohamed Abdel-Mohsen 1 1 Wistar Institute, Philadelphia, PA, USA, 2 Rush University, Chicago, IL, USA, 3 Children's Hospital of Philadelphia, Philadelphia, PA, USA, 4 Weill Cornell Medicine, New York, NY, USA Background: HIV infection disrupts the intestinal barrier, resulting in persistent inflammation, even with antiretroviral therapy (ART). This inflammation contributes to aging-related comorbidities in people with HIV (PWH). However, it remains unclear whether ART-suppressed HIV affects

Poster Abstracts

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CROI 2024