Project description:Dendritic cells (DCs) are essential for antiviral immunity but are also susceptible to HIV-1 infection. Although sensing and restriction pathways in DCs are well described, the mechanisms underlying latent infection and its functional consequences remain unclear. Here, we performed transcriptomic profiling of monocyte-derived DCs harboring transcriptionally active (Active-HIV) or latent HIV-1 (Latent-HIV) proviruses using a dual-reporter virus. Gene set enrichment analysis revealed suppression of metabolic and stress-modulatory programs in Active-HIV compared to unexposed DCs. In contrast, Latent-HIV showed broad downregulation of pathways, including interferon and innate responses and metabolic programs, indicating a hyporesponsive and dampened antiviral state despite the absence of differentially expressed genes (DEGs). DEG analysis of Active-HIV versus Latent-HIV showed that active transcription associates with cellular stress, cytoskeletal remodeling, and RNA-processing. Functional analyses further demonstrated activation of RNA processes, suppression of antigen-presentation pathways, and altered membrane and cytoskeletal signaling in Active-HIV. These pathways suggest that transcriptionally active HIV-1 leverages cellular machinery to support replication, creating a metabolically strained yet immunologically engaged state that disrupts antigen presentation. Conversely, latently infected DCs display a hyporesponsive state consistent with proviral silencing. This dichotomy reveals distinct mechanisms of DC dysfunction that may facilitate HIV-1 persistence and immune evasion.
Project description:A growing body of data suggests that the human brain serves as a sanctuary for HIV persistence despite life-long antiretroviral therapy. Microglia, the innate immune cells of the brain parenchyma, may serve as a reservoir for rebound of HIV infection. The extent of the latent brain reservoir and molecular phenotype of HIV infected microglia cells, however, are unknown. To address this major knowledge gap, we leveraged the ‘Last Gift’ rapid autopsy cohort to perform a multi-omics approach (single cell RNA-seq, single cell ATAC-seq, and H3K27ac ChIP-seq) of the myeloid compartment creating a gene expression and chromatin accessibility atlas of human microglia isolated from three male individuals with HIV on suppressive antiretroviral therapy.
Project description:A growing body of data suggests that the human brain serves as a sanctuary for HIV persistence despite life-long antiretroviral therapy. Microglia, the innate immune cells of the brain parenchyma, may serve as a reservoir for rebound of HIV infection. The extent of the latent brain reservoir and molecular phenotype of HIV infected microglia cells, however, are unknown. To address this major knowledge gap, we leveraged the ‘Last Gift’ rapid autopsy cohort to perform a multi-omics approach (single cell RNA-seq, single cell ATAC-seq, and H3K27ac ChIP-seq) of the myeloid compartment creating a gene expression and chromatin accessibility atlas of human microglia isolated from three male individuals with HIV on suppressive antiretroviral therapy.
Project description:A growing body of data suggests that the human brain serves as a sanctuary for HIV persistence despite life-long antiretroviral therapy. Microglia, the innate immune cells of the brain parenchyma, may serve as a reservoir for rebound of HIV infection. The extent of the latent brain reservoir and molecular phenotype of HIV infected microglia cells, however, are unknown. To address this major knowledge gap, we leveraged the ‘Last Gift’ rapid autopsy cohort to perform a multi-omics approach (single cell RNA-seq, single cell ATAC-seq, and H3K27ac ChIP-seq) of the myeloid compartment creating a gene expression and chromatin accessibility atlas of human microglia isolated from three male individuals with HIV on suppressive antiretroviral therapy.
Project description:Dendritic cells (DC) serve a key function in host defense, linking innate detection of microbes to the activation of pathogen-specific adaptive immune responses. Whether there is cell-intrinsic recognition of HIV-1 by host innate pattern-recognition receptors and subsequent coupling to antiviral T cell responses is not yet known. DC are largely resistant to infection with HIV-1, but facilitate infection of co-cultured T-helper cells through a process of trans-enhancement. We show here that, when DC resistance to infection is circumvented, HIV-1 induces DC maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly-synthesized HIV-1 capsid (CA) with cellular cyclophilin A (CypA) and the subsequent activation of the transcription factor IRF3. Because the peptidyl-prolyl isomerase CypA also interacts with CA to promote HIV-1 infectivity, our results suggest that CA conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell intrinsic sensor for HIV-1 exists in DC and mediates an antiviral immune response, but it is not typically engaged due to absence of DC infection. The virulence of HIV-1 may be related to evasion of this response, whose manipulation may be necessary to generate an effective HIV-1 vaccine. We analyzed the gene expression profiles of uninfected human monocyte-derived dendritic cells (MDDCs) and MDDCs infected with an envelope-defective GFP-encoding VSV-G-pseudotyped HIV-1 vector (HIVGFP(G)) and with VSV-G pseudotyped virus-like particles derived from SIVmac to deliver Vpx (SIVVLP(G)), alone or in combination. Cells were infected at day 4 of differentiation and cells were harvested 48 hours later. RNA was extracted with TRIzol. RNA was labeled and hybridized to Human Genome U133A 2.0 arrays arrays following the Affymetrix protocols. Data were analyzed in R and Bioconductor.
Project description:Despite effective treatment, HIV can persist in latent reservoirs, which represent a major obstacle towards HIV eradication. Targeting and reactivating latent cells is challenging due to the heterogeneous nature of HIV infected cells. Here, we used a primary model of HIV latency and single-cell RNA sequencing to characterize transcriptional heterogeneity during HIV latency and reactivation. Our analysis identified transcriptional programs leading to successful reactivation of HIV expression. We further validated our results using primary CD4+ T cells isolated from HIV+ individuals.
Project description:The study examined proviral and neighboring gene transcription at sites of intact latent HIV-1 integration in cultured T cells obtained directly from people living with HIV, as well as engineered primary T cells and cell lines and showed that the site of integration has a dominant effect on the transcriptional activity of intact HIV-1 proviruses in the latent reservoir