Project description:Molecules mimicking the active N-terminal tetrapeptide of the second mitochondrial-derived activator of caspases (SMACm) potently reverse HIV latency in vitro and ex vivo without the pleotropic cellular effects seen with other LRAs. We verified that SMACm facilitate latency reversal through activation of the non-canonical NFκB pathway as exemplified by rapid degradation of cIAP1, followed by a slower conversion of inactive p100 into active p52. A potent representative of this class, AZD5582, increases cell-associated HIV gag RNA expression in resting CD4+ T cells from ART-suppressed, HIV-infected donors while altering the expression of a restricted number of human genes. These findings represent the first demonstration that SMACm have single agent latency reversal activity in patient-derived cells and support evaluation of SMACm in preclinical animal models.
Project description:Resting CD4+ T cells that are both persistent and latently infected with HIV represent the most important challenge to HIV eradication. Estimates indicate the need for >70 years of continuous, fully suppressive, antiretroviral therapy (ART) to eliminate the HIV reservoir. Alternatively, induction of HIV from its latent state could accelerate the decline of the reservoir, thereby shortening the time to eradication. Previous attempts to reactivate latent HIV in preclinical animal models and in clinical trials have measured HIV induction in peripheral blood with minimal focus on tissue reservoirs and had limited effect. We found that activation of the non-canonical NF-B signaling pathway via AZD5582 results in induction of HIV- and SIV-RNA expression in the blood and tissues of ART-suppressed humanized mice and rhesus macaques. Analysis of resting CD4+ T cells from tissues after AZD55852 treatment revealed increased SIV-RNA in lymph nodes in macaques and robust induction of HIV in virtually all tissues analyzed in humanized mice including lymph nodes, thymus, bone marrow, liver, and lung. This promising new approach to latency reversal, in combination with the appropriate tools for systemic clearance of persistent HIV infection, greatly increases opportunities for HIV eradication.
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:Background: In contrast to HIV-1, lentiviruses of the HIV-2/SIVmac/SIVsmm lineage are capable of efficient replication in myeloid cells due to the presence of their accessory protein Vpx. Vpx has been shown to induce degradation of the dNTP triphosphohydrolase SAMHD1, which is a cellular restriction factor of lentiviral replication. Furthermore, Vpx is important for nuclear import of the viral pre-integration complex. To identify further functions of Vpx, we have analyzed the effect of Vpx on cellular gene expression in monocytes. Therefore, we performed whole genome microarray analysis of unstimulated primary human monocytes treated with SIV–based virus-like particles containing Vpx (VLP+Vpx) or lacking Vpx (VLP). Results: Comparison of the gene expression profiles of human monocytes treated with VLP+Vpx and VLP revealed that Vpx down-regulates various genes involved in innate immunity, in particular genes that are known to be regulated by the transcription factor NF-κB. Subsequent analysis of p65 nuclear translocation revealed that Vpx inhibits the VLP-induced activation of NF-κB. Counteraction of NF-κB was also obtained using Vpx mutants lacking the capacity to induce SAMHD1 degradation. Conclusions: Independent of its capacity to induce degradation of SAMHD1, Vpx is involved in regulation of cellular gene expression. In particular, Vpx is able to modulate innate immune responses through down-regulation of TLR-induced NF-κB activation. This points to a significant role of Vpx in the pathogenicity of SIV, as the lower pathogenicity of SIV compared to HIV-1 has been associated to lower innate immunity responses.
Project description:The goal of this study was to utilize CaptureSeq to be able to measure HIV-1 transcription after reversal of latency in primary cells from antiretroviral-treated HIV-1 infected individuals.
Project description:T cells are the primary target of the virus HIV-1. Upon infection, the expression of the virus may come to a complete shutdown, a phenomenon known as latency. The molecular mechanisms responsible for the latency of HIV-1 are still poorly understood. To shed light on those mechanisms, we used the J-Lat A2 model for latency reversal, that consists of a Jurkat T cell clone containing a mini HIV construct that is transcriptionally silent. We treated J-Lat A2 and Jurkat cells with the latency-reversing drugs SAHA (suberoylanilide hydroxamic acid) and PMA (phorbol 12-myristate 13-acetate), and we performed single-cell RNA-seq to identify transcriptional signatures shared among the cells where HIV is reactivated.
Project description:HIV-1 persistence during ART is due to the establishment of long-lived viral reservoirs in resting immune cells. Using an NHP model of barcoded SIVmac239 intravenous infection and therapeutic dosing of the anti-TGFBR1 inhibitor galunisertib (LY2157299), we confirmed the latency reversal properties of in vivo TGF-beta blockade, decreased viral reservoirs and stimulated immune responses. Eight SIV-infected macaques on suppressive ART were treated with 4 2-week cycles of galunisertib. ART was discontinued 3 weeks after the last dose, and macaques euthanized 6 weeks after ART-interruption(ATI). One macaque did not rebound, while the remaining rebounded between week 2 and 6 post-ATI. Galunisertib led to viral reactivation as indicated by plasma viral load and immunoPET/CT with the 64Cu-DOTA-F(ab')2-p7D3-probe. Half to 1 Log decrease in cell-associated (CA-)SIV DNA was detected in lymph nodes, gut and PBMC, while intact pro-virus in PBMC decreased by 3-fold. No systemic increase in inflammatory cytokines was observed. High-dimensions cytometry, bulk and single-cell RNAseq revealed a shift toward an effector phenotype in T and NK cells.
Project description:HIV-1 persistence during ART is due to the establishment of long-lived viral reservoirs in resting immune cells. Using an NHP model of barcoded SIVmac239 intravenous infection and therapeutic dosing of the anti-TGFBR1 inhibitor galunisertib (LY2157299), we confirmed the latency reversal properties of in vivo TGF-beta blockade, decreased viral reservoirs and stimulated immune responses. Eight SIV-infected macaques on suppressive ART were treated with 4 2-week cycles of galunisertib. ART was discontinued 3 weeks after the last dose, and macaques euthanized 6 weeks after ART-interruption(ATI). One macaque did not rebound, while the remaining rebounded between week 2 and 6 post-ATI. Galunisertib led to viral reactivation as indicated by plasma viral load and immunoPET/CT with the 64Cu-DOTA-F(ab')2-p7D3-probe. Half to 1 Log decrease in cell-associated (CA-)SIV DNA was detected in lymph nodes, gut and PBMC, while intact pro-virus in PBMC decreased by 3-fold. No systemic increase in inflammatory cytokines was observed. High-dimensions cytometry, bulk and single-cell RNAseq revealed a shift toward an effector phenotype in T and NK cells.