CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

EC 50 ranging from 5.3uM to 49.1uM in HIV-1 subtype B and C: CCR5-tropic viruses but not CXCR4-viruses. The viral release assay showed significantly low released measured by p24 in presence of DP-am. Conclusion: We posit that the enriched dipeptides act as CCR5-antagonist that efficiently controls viral replication in EC, and this mechanism contributes to the efficient HIV elite control status.

249 OVERT GUT IL-32 ISOFORM EXPRESSION DURING TREATED HIV INFECTION: REGULATION BY IL-17A

Poster Abstracts

Etiene Moreira Gabriel 1 , Tomas Wiche Salinas 1 , Mohamed El-Far 1 , Etienne Larouche-Anctil 1 , Annie Gosselin 1 , Madeleine Durand 1 , Jean-Pierre Routy 2 , Cécile L. Tremblay 1 , Petronela Ancuta 1 1 Centre de Recherche du CHUM, Montreal, QC, Canada, 2 McGill University, Montreal, QC, Canada Background: The interplay between intestinal epithelial cells (IEC) and Th17 cells is key for mucosal immunity homeostasis. HIV infection provokes intestinal barrier function impairment and chronic immune activation, which are not normalized by antiretroviral therapy (ART). Such alterations coincide with the overexpression of IL-32, a newly described cytokine, with multiple isoforms. IL-32 overexpression was predictive of the loss of viral control in HIV slow progressors and associated with non-AIDS co-morbidities such as cardiovascular disease (CVD). The role of specific IL-32 isoforms in HIV pathogenesis remains poorly investigated. Here, we quantified the expression of IL-32 isoforms in the colon and blood of ART-treated people living with HIV (ART+PLWH), and explored the regulation of IL-32 expression by the Th17 hallmark cytokine IL-17A. Methods: Matched PBMC and sigmoid colon biopsies were available from n=17 ART+PLWH (median age: 55 years; CD4 counts: 679 cells/ul; time on ART: 72 months) and n=5 age-matched HIV-uninfected controls. The HT-29 IEC line was used to study the modulation of IL-32 expression upon exposure to recombinant TNF-α and/or IL-17A, the TLR-3 agonist Poly:IC, or the HIV NL4.3BaL or THRO strains. IL-32α, β, γ, d, ε, t mRNA expression was measured by real-time RT-PCR. IL-32 protein production was measured in cell-culture supernatant and cell lysates by ELISA. Results: Our results reveal a significant increase in IL-32 mRNA expression, specifically IL-32β and ε, in colon biopsies and PBMC of ART+PLWH compared to uninfected controls. IL-32 mRNA expression, especially IL-32β, γ and ε, was induced by exposure of HT-29 cells to recombinant TNF-α, Poly:IC and HIV THRO strain. IL-32 mRNA levels positively correlated with intracellular IL-32 protein expression, but no soluble IL-32 was detected in cell culture supernatants, indicative that IL-32 protein expression in IEC is mainly intracellular. Of note, recombinant IL-17A significantly decreased IL-32 mRNA/protein expression induced by TNF-α and Poly:IC, supporting an immune-regulatory role played by IL-17A. Conclusion: Our results document the overexpression of specific IL-32 isoforms in colon biopsies and PBMC of ART-treated PLWH and point to the negative consequences of mucosal Th17 paucity, in line with our discovery that IL-17A acts as a negative regulator of IL-32 isoforms with pro-inflammatory and/or antiviral features.

250 DISTINCT INTERFEROMES ASSOCIATE WITH CHRONIC HIV PATHOGENESIS IN THE GUT Stephanie Dillon 1 , Kejun Guo 1 , Guannan Shen 1 , Harry Smith 1 , Miranda E. Kroehl 1 , Katerina Kechris 1 , Cara Wilson 1 , Mario Santiago 1 1 University of Colorado Anschutz Medical Campus, Aurora, CO, USA Background: Type I Interferons (IFN-Is) protect against early HIV infection, but were linked to pathogenesis during the chronic stages. Previously, we showed that IFNβ, but not IFNα, was upregulated in the colon of chronically infected people with HIV (PWH) relative to uninfected persons (PMID29762170). To gain understanding on how IFNβ may influence chronic gut HIV pathogenesis, we profiled the transcriptome of uninfected gut CD4 T cells exposed to dominant IFNα subtypes or IFNβ in vitro. This analysis revealed a set of IFN-stimulated genes (ISGs) upregulated by all IFN-Is tested (core ISGs) and genes specifically induced by IFNβ (βISGs). Here, we evaluated these 2 gene sets in chronic, untreated HIV-1 infection. Methods: Colon biopsies (previously collected with informed consent) from 19 untreated, chronically infected PWH (median VL 26000 HIV-1 RNA/ml; median CD4 count 429 cells/μl) and 13 uninfected controls were transcriptomically profiled using RNAseq. Differential gene analysis was conducted using edgeR and correlations between ISGs and clinical/immunological parameters tested using linear regression models adjusted for age and gender and corrected for multiple comparisons. Significance was established at FDR <5% for all analyses. Results: Of 246 core ISGs, 51%were significantly altered in PWH vs. controls. Of these 126 altered core ISGs, 89%were upregulated in PWH. Upregulated core ISGs included genes linked to innate sensing (e.g. IRF9 3.9x; NLRC5 3.5x), immune activation (e.g. CD38 2.4x) and exhaustion (e.g. LAG3 6.2x). Majority (78%) of altered core ISGs positively correlated with gut IFNβ transcripts and plasma LPS levels and inversely with gut CD4 T cell frequencies. Of 406 βISGs, 28%were significantly altered in PWH. Of these 112 altered βISGs, >90% were downregulated in PWH and included genes linked to anti-inflammatory responses (e.g. SMAD4 -1.5x) and maintaining genomic DNA integrity (e.g. NUP54 -1.6x, MUS81 -1.6x). In contrast to the core ISGs, majority (85%) of altered βISGs inversely correlated with IFNβ and LPS levels, and 50% positively correlated with gut CD4 T cell frequencies. Conclusion: Our data reveals a complex picture of how IFNβ may promote HIV pathogenesis in the gut. While IFNβ is associated with increased core ISG expression linked to inflammation, immune activation and exhaustion, it is also linked to decreased expression of genes with potential anti-inflammatory properties. These data could guide IFN-I blockade strategies to reduce chronic inflammation in PWH.

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CROI 2020