Project description:We sought to explore the hypothesis that host factors required for HIV-1 replication also play a role in latency reversal. Using a CRISPR gene library of putative HIV dependency factors, we performed a screen to identify genes required for latency reactivation. We identified several HIV- 1 dependency factors that play a key role in HIV-1 latency reactivation including ELL, UBE2M, TBL1XR1, HDAC3, AMBRA1, and ALYREF. Knockout of Cyclin T1 (CCNT1), a component of the P-TEFb complex important for transcription elongation, was the top hit in the screen and had the largest effect on HIV latency reversal with a wide variety of latency reversal agents. Moreover, CCNT1 knockout prevents latency reactivation in a primary CD4+ T cell model of HIV latency without affecting activation of these cells. RNA sequencing data showed that CCNT1 regulates HIV-1 proviral genes to a larger extent than any other host gene and had no significant effects on RNA transcripts in primary T cells after activation. We conclude that CCNT1 function is redundant in T cells but is absolutely required for HIV latency reversal.
Project description:We sought to explore the hypothesis that host factors required for HIV-1 replication also play a role in latency reversal. Using a CRISPR gene library of putative HIV dependency factors, we performed a screen to identify genes required for latency reactivation. We identified several HIV- 1 dependency factors that play a key role in HIV-1 latency reactivation including ELL, UBE2M, TBL1XR1, HDAC3, AMBRA1, and ALYREF. Knockout of Cyclin T1 (CCNT1), a component of the P-TEFb complex important for transcription elongation, was the top hit in the screen and had the largest effect on HIV latency reversal with a wide variety of latency reversal agents. Moreover, CCNT1 knockout prevents latency reactivation in a primary CD4+ T cell model of HIV latency without affecting activation of these cells. RNA sequencing data showed that CCNT1 regulates HIV-1 proviral genes to a larger extent than any other host gene and had no significant effects on RNA transcripts in primary T cells after activation. We conclude that CCNT1 function is redundant in T cells but is absolutely required for HIV latency reversal.
Project description:The goal of this CRISPR-based screen (Latency HIV-CRISPR) is to identify HIV-1 latency factors by evaluating multiple pathways simultaneously. Here are Illumina sequencing data and counts files from a Latency HIV-CRISPR screen using a custom guide RNA library targeting human epigenome genes (HuEpi). The Latency HIV-CRISPR screens described here were performed in clonal ZAP knockout J-Lat 10.6 (PMID: 12682019) or J-Lat 5A8 (PMID: 24204950) cells lines as ZAP inhibition of the HIV-CRISPR vector has been previously described (PMID: 30520725). The screens were performed in the presence or absence of AZD5582, a SMAC mimetic and latency reversal agent, in order to identify factors that are dependent and independent of this transcriptional activator.
Project description:To identify novel host factors as putative targets to reverse HIV-1 latency, we performed an insertional mutagenesis genetic screen in a latently HIV-1-infected pseudohaploid KBM7 cell line (Hap-Lat). Following mutagenesis, insertions were mapped to the genome, and bioinformatic analysis resulted in the identification of 69 candidate host genes involved in maintaining HIV-1 latency.
Project description:Latency reversal and clearance strategies for HIV cure are beginning to employ IAP antagonists (IAPi) to induce unprecedented levels of latent reservoir expression without immunotoxicity during suppressive antiretroviral therapy (ART). However, full targeting of the reservoir may require combinatorial approaches. A Jurkat latency model screen for IAPi combination partners demonstrated synergistic latency reversal with Bromodomain and Extra-Terminal domain protein inhibitors (BETi). Mechanistic investigations using CRISPR-CAS9 and single cell-RNAseq informed comprehensive ex vivo evaluations of IAPi plus pan-BET, bromodomain (BD)-selective BET, or selective BET isoform targeting in CD4 T cells from ART-suppressed donors. IAPi+BETi treatment resulted in striking induction of cell-associated HIV gag RNA but lesser induction of fully elongated and tat-rev RNA, especially compared to T cell activation positive controls. IAPi/BETi resulted in HIV protein induction in bulk cultures of CD4 T cells using an ultrasensitive p24 assay, but did not translate to enhanced viral outgrowth frequency using a standard quantitative viral outgrowth assay. Overall, this study defines HIV transcriptional elongation and splicing as key barriers to latent HIV protein expression following latency reversal, delineates the roles of BET proteins and their bromodomains in HIV latency, and provides rationale for testing of IAPi+BETi in animal models of HIV latency.
Project description:Purpose: The goal of this study is to identify host micro RNAs (miRNAs) whose expression is dysregulated during HIV latency, cell activation and productive infection. This information provides a mechanistic insight into an additional layer of miRNA-mediated regulation of gene expression and cellular pathways that are involved in HIV latency establishment and maintenance. Methods: An in vitro model of HIV latency and mock-infected cells before and after activation with antiCD3/antiCD28 coated magnetic beads was used for miRNA expression profiling using small RNA sequencing (smRNA-Seq). Results: Read counts of the 418 miRNAs survived filtering. Differential expression analysis identified 26 miRNAs dysregulated in latency. Messenger RNA (mRNA) targets and cellular pathways enriched for mRNA targets were identified using several analytical methods. Our analyses showed that many protein-coding genes and pathways targeted by dysregulated miRNAs have relevance to regulation of HIV expression or establishment of HIV latency. The p53 signalling pathway was found among pathways that were targeted by dysregulated miRNAs at a greater level than expected by chance. Conclusions: The present study identifies miRNAs dysregulated during HIV latency and provides a mechanistic insight into regulation of the p53 pathway via miRNAs that may contribute to latency establishment.
Project description:Transcriptional silencing of latent HIV-1 proviruses entails complex and overlapping mechanisms and are a major barrier to in vivo elimination of HIV-1. We developed a new latency CRISPR screening strategy, called Latency HIV-CRISPR, which uses the packaging of guideRNA-encoding lentiviral vector genomes into the supernatant of budding virions as a direct readout of factors involved in the maintenance of HIV-1 latency. We developed a custom guideRNA library targeting epigenetic regulatory genes and paired the screen with and without a latency reversal agent – AZD5582, an activator of the non-canonical NFkB pathway – to examine a combination of mechanisms controlling HIV-1 latency. A component of the Nucleosome Acetyltransferase of H4 histone acetylation (NuA4 HAT) complex, ING3, acts in concert with AZD5582 to activate proviruses in J-Lat cell lines and in a primary CD4+ T cell model of HIV-1 latency. We found that the knockout of ING3 reduces acetylation of the H4 histone tail and BRD4 occupancy on the HIV-1 LTR, and the combination of ING3 knockout with the activation of non-canonical NFkB via AZD5582 act together to dramatically increase initiation and elongation of RNA Polymerase II on the HIV-1 provirus in a manner that is nearly unique among all cellular promoters.