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
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
Project description:Human immunodeficiency virus (HIV) infection is a chronic condition, where viral DNA integrates into the genome. The fate of the provirus determines the infection course. Latently infected cells form a persistent, heterogeneous reservoir. The reservoir that reinstates an active infection comprises cells with intact provirus that can be reactivated. We confirmed that latent cells from patients exhibited active transcription throughout the provirus. To find transcriptional determinants, we characterized the establishment and maintenance of latency during proviral chromatin maturation in primary CD4+ T-cells for four months after HIV infection. As heterochromatin (marked with H3K9me3 or H3K27me3) gradually stabilized, the provirus became less accessible and lost activation potential. In a subset of infected cells, active marks (i.e., H3K27ac) remained detectable, even after prolonged proviral silencing. After T-cell activation, the proviral activation occurred uniquely in cells with H3K27ac-marked proviruses. Our observations suggested that, after transient proviral activation, cells were actively returned to latency.
Project description:We investigated the link between HIV-1 integration by using B-HIVE and LEDGINs. B-HIVE tracks insert-specific HIV expression by tagging a unique barcode in the HIV genome. LEDGINs are antivirals that inhibit the interaction between HIV-IN and its chromatin tethering cofactor LEDGF/p75. They are known to retarget HIV-1 integration sites. Here, we confirmed that LEDGIN treatment retargets integration out of transcriptionally active regions and reduce HIV expression. Silent provirus was located at increased distance to H3K36me3, the recognition marker of LEDGF/p75, after treatment with LEDGINs. Viral RNA expression was also influenced by the proximity of enhancers, regardless of the presence of LEDGINs.
Project description:Antiretroviral therapy controls but does not cure HIV-1 infection due to a reservoir of rare CD4 + T cells harboring latent proviruses. Little is known about the transcriptional program of latent cells. Here we report a novel strategy to enrich clones of latent cells carrying intact, replication-competent HIV-1 proviruses from blood based on their expression of unique T cell receptors. Latent cell enrichment enabled single cell transcriptomic analysis of 1,050 CD4 + T cells belonging to expanded clones harboring intact HIV-1 proviruses from 6 different individuals. The analysis revealed that most of these cells are T effector memory cells that are enriched for expression of HLA-DR, HLA-DP, CD74, CCL5, Granzymes A and K, cystatin F, LYAR and DUSP2. We conclude that expanded clones of latent cells carrying intact HIV-1 proviruses persist preferentially in a distinct CD4 + T cell population opening new possibilities for eradication.
Project description:Background and objectivesHIV-1 provirus integration in host genomes provides a lifelong reservoir of virally infected cells. Although not able to generate viral progeny, the expression of defective proviruses has been associated with activation. Provirus integration may influence host gene transcription and shifts may occur during disease progression or antiretroviral therapy (ART). The study aimed to analyze intact/defective provirus and sites of provirus integration in acute infections: changes after 48 weeks of early therapy were also evaluated.MethodsDNA from peripheral blood lymphomonocytes of 8 acute HIV-1 infections at serodiagnosis (T0) and after 48 weeks of therapy (T1) was used to quantify intact and defective provirus by digital-droplet PCR and to analyze provirus integration sites, by next-generation sequencing of libraries derived from ligation-mediated PCR.ResultsA high variability in the amount of intact proviral DNA was observed at both T0 and T1, in the different subjects. Although the ratio of intact/total proviral HIV-1 DNA did not dramatically change between T0 (8.05%) and T1 (9.34%), after early therapy both intact and total HIV-1 DNA declined significantly, p = 0.047 and p = 0.008, respectively. The median number of different (IQR) integration sites in human chromosomes/subject was 5 (2.25-13.00) at T0 and 4 (3.00-6.75) at T1. Of all the integration sites observed at T1, 64% were already present at T0. Provirus integration was observed in introns of transcriptionally active genes. Some sites of integration, among which the most represented was in the neuregulin 2 gene, were shared by different patients, together with the orientation of the insertion. Provirus integration was also observed in intergenic regions, with median (IQR) % of 15.13 (6.81-21.40) at T0 and 18.46 (8.98-22.18) at T1 of all read matches.ConclusionsIn acute HIV-1 infection, the amount of intact proviral DNA in peripheral lymphomonocytes did not exceed 10% of total HIV-1 DNA, a percentage that was not substantially changed by early administrated ART. Provirus displayed a relatively small number of recurrent integration sites in introns of transcriptionally active genes, mainly related to cell-cycle control. Consideration should be given to therapeutic strategies able to target the cells harboring defective proviruses, that are not reached by conventional antiviral drugs, these potentially also impacting on replicative competent integrated provirus.