Despite the success of combination antiretroviral therapy (cART), HIV persists in long lived latently infected cells in the blood and tissue, and treatment is required lifelong. Recent clinical studies have trialed latency-reversing agents (LRA) as a method to eliminate latently infected cells; however, the effects of LRA on the central nervous system (CNS), a well-known site of virus persistence on cART, are unknown. In this study, we evaluated the toxicity and potency of a panel of commonly used and well-known LRA (panobinostat, romidepsin, vorinostat, chaetocin, disulfiram, hexamethylene bisacetamide [HMBA], and JQ-1) in primary fetal astrocytes (PFA) as well as monocyte-derived macrophages as a cellular model for brain perivascular macrophages. We show that most LRA are non-toxic in these cells at therapeutic concentrations. Additionally, romidepsin, JQ-1, and panobinostat were the most potent at inducing viral transcription, with greater magnitude observed in PFA. In contrast, vorinostat, chaetocin, disulfiram, and HMBA all demonstrated little or no induction of viral transcription. Together, these data suggest that some LRA could potentially activate transcription in latently infected cells in the CNS. We recommend that future trials of LRA also examine the effects of these agents on the CNS via examination of cerebrospinal fluid.
BackgroundDifferent classes of latency reversing agents (LRAs) are being evaluated to measure their effects in reactivating HIV replication from latently infected cells. A limited number of studies have demonstrated additive effects of LRAs with the viral protein Tat in initiating transcription, but less is known about how LRAs interact with Tat, particularly through basic residues that may be post-translationally modified to alter the behaviour of Tat for processive transcription and co-transcriptional RNA processing.ResultsHere we show that various lysine and arginine mutations reduce the capacity of Tat to induce both transcription and mRNA splicing. The lysine 28 and lysine 50 residues of Tat, or the acetylation and methylation modifications of these basic amino acids, were essential for Tat transcriptional control, and also for the proviral expression effects elicited by histone deacetylase inhibitors (HDACi) or the bromodomain inhibitor JQ1. We also found that JQ1 was the only LRA tested that could induce HIV mRNA splicing in the absence of Tat, or rescue splicing for Tat lysine mutants in a BRD4-dependent manner.ConclusionsOur data provide evidence that Tat activities in both co-transcriptional RNA processing together with transcriptional initiation and processivity are crucial during reactivation of latent HIV infection. The HDACi and JQ1 LRAs act with Tat to increase transcription, but JQ1 also enables post-transcriptional mRNA splicing. Tat residues K28 and K50, or their modifications through acetylation or methylation, are critical for LRAs that function in conjunction with Tat.Electronic supplementary materialThe online version of this article (10.1186/s12977-018-0421-6) contains supplementary material, which is available to authorized users.
Respiratory bacterial-viral coinfections (such as pneumococci and influenza virus) are often synergistic, resulting in enhanced disease severity. Although colonization of the nasopharynx is the precursor to disease and transmission, little is known about bacterial-viral interactions that occur within this niche.
Context In contrast with other respiratory viruses, children infected with SARS-CoV-2 are largely spared from severe COVID-19. Objectives To critically assess age-related differences in three host proteins involved in SARS-CoV-2 cellular entry: angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin. Methods We systematically searched Medline, Embase, and PubMed databases for relevant publications. Studies were eligible if they evaluated ACE2, TMPRSS2 or furin expression, methylation, or protein level in children. Results Sixteen papers were included. Age-dependent differences in membrane-bound and soluble ACE2 were shown in several studies, with ACE2 expression increasing with age. TMPRSS2 and furin are key proteases involved in SARS-CoV-2 spike protein cleavage. TMPRSS2 expression is increased by circulating androgens and is thus low in pre-pubertal children. Furin has not currently been well researched. Limitations High levels of study heterogeneity. Conclusions Low expression of key host proteins may partially explain the reduced incidence of severe COVID-19 among children, although further research is needed.
Background: Drug hepatotoxicity is a potentially serious adverse reaction of antiretroviral therapy in human immunodeficiency virus‐infected patients. The impact of this problem in the routine treatment of patients with human immunodeficiency virus infection is poorly defined. Objectives: Our aim was to determine what clinical features are associated with hepatotoxicity in human immunodeficiency virus‐infected patients receiving antiretroviral therapy. Methods: Consecutive patients in a primary care‐based human immunodeficiency virus clinic were evaluated for hepatotoxicity. Clinic records were used to obtain patient characteristics, as well as independent variables including CD4+ count, coexisting hepatitis C and current alcohol use. Results: Sixty‐five patients taking antiretroviral therapy were evaluated. Twenty‐four were identified to have antiretroviral hepatotoxicity. An age over 40 years (P=0.019), an absolute CD4+ count of less than 310 cells/mL (P=0.002) and coexisting hepatitis C infection (P=0.035) were significantly associated with hepatotoxicity. Patients older than 40 years had a sevenfold increased risk (risk ratio, 6.9; 95% confidence interval, 1.7–27.3) and those with an absolute CD4+ count of less than 310 cells/mL had a tenfold increased risk (risk ratio, 10.2; 95% confidence interval, 2.5–41.9) for antiretroviral hepatotoxicity, in comparison with those who were younger or who had a greater absolute CD4+ count. Of the eight patients documented to have coexisting hepatitis C infection, six (75%) were in the antiretroviral hepatotoxicity group. Conclusions: An age older than 40 years and an absolute CD4+ count of less than 310 cells/mL were significantly associated with antiretroviral‐induced hepatotoxicity. The majority of our patients with chronic hepatitis C had hepatotoxicity from antiretroviral therapy.
OBJECTIVE:To determine whether latency can be established and reversed in both proliferating and non-proliferating CD4 + T cells in the same model in vitro.METHODS: Activated CD4 + T cells were infected with either a non-replication competent, luciferase reporter virus or wild-type full-length enhanced green fluorescent protein (EGFP) reporter virus and cultured for 12 days. The cells were then sorted by flow cytometry to obtain two distinct T cell populations that did not express the T cell activation markers, CD69, CD25 and HLA-DR: CD69 − CD25 − HLA-DR − small cells (non-blasts) that had not proliferated in vitro following mitogen stimulation and CD69 − CD25 − HLA-DR − large cells (which we here call transitional blasts) that had proliferated. The cells were then reactivated with latency reversing agents (LRAs) and either luciferase or EGFP quantified.
The persistent reservoir of cells latently infected with human immunodeficiency virus (HIV)-integrated proviral DNA necessitates lifelong suppressive antiretroviral therapy (ART). Epigenetic targeted compounds have shown promise as potential latency-reversing agents; however, these drugs have undesirable toxicity and lack specificity for HIV. We utilized a novel HEK293-derived FlpIn dual-reporter cell line, which quantifies specific HIV provirus reactivation (LTR promoter) relative to nonspecific host cell gene expression (CMV promoter), to identify the 5-substituted 2-acylaminothiazole hit class. Here, we describe the optimization of the hit class, defining the functionality necessary for HIV gene activation and for improving in vitro metabolism and solubility. The optimized compounds displayed enhanced HIV gene expression in HEK293 and Jurkat 10.6 latency cellular models and increased unspliced HIV RNA in resting CD4+ T cells isolated from HIV-infected individuals on ART, demonstrating the potential of the 2-acylaminothiazole class as latency-reversing agents.
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