The persistent pool of HIV-1-infected cells is formed episodically during untreated infection.

Previous studies have shown that the majority of long-lived cells harboring persistent HIV-1 proviral genomes originates from viruses circulating in the year prior to antiretroviral therapy (ART) initiation, but a smaller proportion originates from viruses circulating much earlier in untreated infection. These observations suggest that discrete biological factors influence the entry and persistence of viruses into the persistent proviral pool, and there may be periods earlier in untreated infection with increased seeding. Therefore, we examined the timing of formation of the long-lived pool of infected cells that persists during ART in seven women (after a median of 5.

The histone methyltransferase SETD2 regulates HIV expression and latency.

Understanding the mechanisms that drive HIV expression and latency is a key goal for achieving an HIV cure. Here we investigate the role of the SETD2 histone methyltransferase, which deposits H3K36 trimethylation (H3K36me3), in HIV infection. We show that prevention of H3K36me3 by a potent and selective inhibitor of SETD2 (EPZ-719) leads to reduced post-integration viral gene expression and accelerated emergence of latently infected cells.

The timing of HIV-1 infection of cells that persist on therapy is not strongly influenced by replication competency or cellular tropism of the provirus.

People with HIV-1 (PWH) on antiretroviral therapy (ART) can maintain undetectable virus levels, but a small pool of infected cells persists. This pool is largely comprised of defective proviruses that may produce HIV-1 proteins but are incapable of making infectious virus, with only a fraction (~10%) of these cells harboring intact viral genomes, some of which produce infectious virus following ex vivo stimulation (i.e.

Nonsuppressible viremia during HIV-1 therapy meets molecular virology.

HIV-1 replication can be suppressed with antiretroviral therapy (ART), but individuals who stop taking ART soon become viremic again. Some people experience extended times of detectable viremia despite optimal adherence to ART. In this issue of the JCI, White, Wu, and coauthors elucidate a source of nonsuppressible viremia (NSV) in treatment-adherent patients - clonally expanded T cells harboring HIV-1 proviruses with small deletions or mutations in the 5'-leader, the UTR that includes the major splice donor site of viral RNA.

Encoded Conformational Dynamics of the HIV Splice Site A3 Regulatory Locus: Implications for Differential Binding of hnRNP Splicing Auxiliary Factors.

Alternative splicing of the HIV transcriptome is controlled through cis regulatory elements functioning as enhancers or silencers depending on their context and the type of host RNA binding proteins they recruit. Splice site acceptor A3 (ssA3) is one of the least used acceptor sites in the HIV transcriptome and its activity determines the levels of tat mRNA. Splice acceptor 3 is regulated by a combination of cis regulatory sequences, auxiliary splicing factors, and presumably RNA structure.

Combined noncanonical NF-κB agonism and targeted BET bromodomain inhibition reverse HIV latency ex vivo.

Latency reversal strategies for HIV cure using inhibitor of apoptosis protein (IAP) antagonists (IAPi) 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 (BD) and extraterminal domain protein inhibitors (BETi).

Epitranscriptomic addition of mA regulates HIV-1 RNA stability and alternative splicing.

Previous work has demonstrated that the epitranscriptomic addition of mA to viral transcripts can promote the replication and pathogenicity of a wide range of DNA and RNA viruses, including HIV-1, yet the underlying mechanisms responsible for this effect have remained unclear. It is known that mA function is largely mediated by cellular mA binding proteins or readers, yet how these regulate viral gene expression in general, and HIV-1 gene expression in particular, has been controversial. Here, we confirm that mA addition indeed regulates HIV-1 RNA expression and demonstrate that this effect is largely mediated by the nuclear mA reader YTHDC1 and the cytoplasmic mA reader YTHDF2.

HIV-1: To Splice or Not to Splice, That Is the Question.

The transcription of the HIV-1 provirus results in only one type of transcript-full length genomic RNA. To make the mRNA transcripts for the accessory proteins Tat and Rev, the genomic RNA must completely splice. The mRNA transcripts for Vif, Vpr, and Env must undergo splicing but not completely.

Author Correction: Determination of RNA structural diversity and its role in HIV-1 RNA splicing.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Determination of RNA structural diversity and its role in HIV-1 RNA splicing.

Human immunodeficiency virus 1 (HIV-1) is a retrovirus with a ten-kilobase single-stranded RNA genome. HIV-1 must express all of its gene products from a single primary transcript, which undergoes alternative splicing to produce diverse protein products that include structural proteins and regulatory factors. Despite the critical role of alternative splicing, the mechanisms that drive the choice of splice site are poorly understood.

Acetylation of Cytidine Residues Boosts HIV-1 Gene Expression by Increasing Viral RNA Stability.

Epitranscriptomic RNA modifications, including methylation of adenine and cytidine residues, are now recognized as key regulators of both cellular and viral mRNA function. Moreover, acetylation of the N position of cytidine (ac4C) was recently reported to increase the translation and stability of cellular mRNAs. Here, we show that ac4C and N-acetyltransferase 10 (NAT10), the enzyme that adds ac4C to RNAs, have been subverted by human immunodeficiency virus 1 (HIV-1) to increase viral gene expression.

The ResidentialCare Transition Module: a single-blinded randomized controlled evaluation of a telehealth support intervention for family caregivers of persons with dementia living in residential long-term care.

Background: Families do not fully disengage from care responsibilities following relatives' admissions to residential long-term (RLTC) care settings such as nursing homes. Caregiver stress, depression, or other key outcomes remain stable or sometimes increase following a relative's RLTC entry. Some interventions have attempted to increase family involvement after institutionalization, but few rigorous studies have demonstrated whether these interventions are effective in helping families navigate the potential emotional and psychological upheaval presented by relatives' transitions to RLTC environments.

Epitranscriptomic Addition of mC to HIV-1 Transcripts Regulates Viral Gene Expression.

How the covalent modification of mRNA ribonucleotides, termed epitranscriptomic modifications, alters mRNA function remains unclear. One issue has been the difficulty of quantifying these modifications. Using purified HIV-1 genomic RNA, we show that this RNA bears more epitranscriptomic modifications than the average cellular mRNA, with 5-methylcytosine (mC) and 2'O-methyl modifications being particularly prevalent.

Genome-Wide Analysis of Heterogeneous Nuclear Ribonucleoprotein (hnRNP) Binding to HIV-1 RNA Reveals a Key Role for hnRNP H1 in Alternative Viral mRNA Splicing.

Alternative splicing of HIV-1 mRNAs increases viral coding potential and controls the levels and timing of gene expression. HIV-1 splicing is regulated in part by heterogeneous nuclear ribonucleoproteins (hnRNPs) and their viral target sequences, which typically repress splicing when studied outside their native viral context. Here, we determined the location and extent of hnRNP binding to HIV-1 mRNAs and their impact on splicing in a native viral context.

Global synonymous mutagenesis identifies cis-acting RNA elements that regulate HIV-1 splicing and replication.

The ~9.5 kilobase HIV-1 genome contains RNA sequences and structures that control many aspects of viral replication, including transcription, splicing, nuclear export, translation, packaging and reverse transcription. Nonetheless, chemical probing and other approaches suggest that the HIV-1 genome may contain many more RNA secondary structures of unknown importance and function.

Virion-Associated Vpr Alleviates a Postintegration Block to HIV-1 Infection of Dendritic Cells.

Viral protein R (Vpr) is an HIV-1 accessory protein whose function remains poorly understood. In this report, we sought to determine the requirement of Vpr for facilitating HIV-1 infection of monocyte-derived dendritic cells (MDDCs), one of the first cell types to encounter virus in the peripheral mucosal tissues. In this report, we characterize a significant restriction of Vpr-deficient virus replication and spread in MDDCs alone and in cell-to-cell spread in MDDC-CD4 T cell cocultures.

Characterizing HIV-1 Splicing by Using Next-Generation Sequencing.

Full-length human immunodeficiency virus type 1 (HIV-1) RNA serves as the genome or as an mRNA, or this RNA undergoes splicing using four donors and 10 acceptors to create over 50 physiologically relevant transcripts in two size classes (1.8 kb and 4 kb). We developed an assay using Primer ID-tagged deep sequencing to quantify HIV-1 splicing.

Rb1 and Pten Co-Deletion in Osteoblast Precursor Cells Causes Rapid Lipoma Formation in Mice.

The Rb and Pten tumor suppressor genes are important regulators of bone development and both are frequently mutated in the bone cancer osteosarcoma (OS). To determine if Rb1 and Pten synergize as tumor suppressor genes for osteosarcoma, we co-deleted them in osteoprogenitor cells. Surprisingly, we observed rapid development of adipogenic but not osteosarcoma tumors in the ΔRb1/Pten mice.

Deletion of histone deacetylase 7 in osteoclasts decreases bone mass in mice by interactions with MITF.

Molecular regulators of osteoclast formation and function are an important area of research due to the central role of osteoclasts in bone resorption. Transcription factors such as MITF are essential for osteoclast generation by regulating expression of the genes required for cellular differentiation and resorptive function. We recently reported that histone deacetylase 7 (HDAC7) binds to and represses the transcriptional activity of MITF in osteoclasts, and that loss of HDAC7 in vitro accelerated osteoclastogenesis.

Bone morphogenetic proteins signal via SMAD and mitogen-activated protein (MAP) kinase pathways at distinct times during osteoclastogenesis.

To investigate the role of bone morphogenetic protein (BMP) signaling in osteoclastogenesis in vivo, we eliminated BMPRII in osteoclasts by creating a BMPRII(fl/fl);lysM-Cre mouse strain. Conditional knock-out (cKO) mice are osteopetrotic when compared with WT controls due to a decrease in osteoclast activity. Bone marrow macrophages (BMMs) isolated from cKO mice are severely inhibited in their capacity to differentiate into mature osteoclasts in the presence of M-CSF and receptor activator of NF-κB (RANK) ligand.

Long-term follow up of patients undergoing reoperative surgery with aortic or mitral valve replacement using a St. Jude Medical prosthesis.

Background And Aim Of The Study: Between June 1978 and September 2002, a total of 440 reoperative open-heart patients (mean age 62 +/- 14 years; range: 18-91 years), following various primary cardiac operations, underwent single-valve replacement with the St. Jude Medical (SJM) heart valve. Of 241 patients having aortic replacement (AVR) and 199 mitral valve replacement (MVR), 86 (35%) and 42 (21%), respectively, underwent concomitant coronary artery bypass grafting.