Modulation of HIV-1 virulence via the host glucocorticoid receptor: towards further understanding the molecular mechanisms of HIV-1 pathogenesis

Circadian orchestration of host and gut microbiota in infection

Circadian rhythms are present in almost every organism and regulate multiple aspects of biological and physiological processes (e.g. metabolism, immune responses, and microbial exposure). There exists a bidirectional circadian interaction between the host and its gut microbiota, and potential circadian orchestration of both host and gut microbiota in response to invading pathogens. In this review, we summarize what is known about these intestinal microbial oscillations and the relationships between host circadian clocks and various infectious agents (bacteria, fungi, parasites, and viruses), and discuss how host circadian clocks prime the immune system to fight pathogen infections as well as the direct effects of circadian clocks on viral activity (e.g. SARS-CoV-2 entry and replication). Finally, we consider strategies employed to realign normal circadian rhythmicity for host health, such as chronotherapy, dietary intervention, good sleep hygiene, and gut microbiota-targeted therapy. We propose that targeting circadian rhythmicity may provide therapeutic opportunities for the treatment of infectious diseases.

Increased HIV-1 infection in PBMCs treated in vitro with menstrual cycle phase hormones or medroxyprogesterone acetate likely occurs via different mechanisms

PROBLEM

Both luteal phase progesterone (P4) levels and use of the intramuscular (IM) injectable progestin-only contraceptive depo-medroxyprogesterone acetate (DMPA-IM) have been linked to increased S/HIV acquisition in animal, clinical and in vitro models. Several plausible mechanisms could explain MPA-induced HIV-1 acquisition while those for the luteal phase are underexplored.

METHOD OF STUDY

Peripheral blood mononuclear cells (PBMCs) were treated with P4 and estrogen at concentrations mimicking the luteal phase, follicular phase or with levels of MPA mimicking peak serum levels in DMPA-IM users. Cells were infected with an R5-tropic infectious molecular clone and HIV-1 infection was measured. A role for the glucocorticoid receptor (GR) was investigated using the GR/PR antagonist RU486. CCR5 protein levels and activation status, assessed by levels of the activation marker CD69, were measured by flow cytometry after treatment in vitro and in PBMCs from naturally-cycling women or DMPA-IM users.

RESULTS

Both MPA and luteal phase hormones significantly increased HIV-1 infection in vitro. However, MPA but not luteal phase hormones increased the CD4+/CD8+ T cell ratio, CCR5 protein expression on CD4+ T cells and increased expression of the activation marker CD69. The GR is involved in MPA-induced, but not luteal phase hormone-induced increased HIV-1 infection. In DMPA-IM users, the frequency of CCR5-expressing CD3+ and CD8+ cells was higher than for women in the luteal phase.

CONCLUSIONS

MPA increases HIV-1 infection in a manner different from that of luteal phase hormones, most likely involving the GR and at least in part changes in the frequency and/or expression of CCR5 and CD69.

Hormonally Active Contraceptives Part I: Risks Acknowledged and Unacknowledged

Hormonal contraceptives have been on the market for over fifty years and, while their formulations have changed, the basic mechanism of action has remained the same. During this time, numerous studies have been performed documenting side effects, some of which appear over time, some within weeks or months, but all can have a serious impact on health and quality of life. An effort was made to perform a series of comprehensive literature surveys to better understand immediate and long-term side effects of these agents. The results of this literature review uncovered a number of potential side effects, some of which are acknowledged and many of which are not noted in the prescribing information for these agents. Among the unacknowledged side effects are: an increased risk of HIV transmission for depot medroxyprogesterone acetate (DMPA), and for combination contraceptives breast cancer, cervical cancer, Crohn's disease, ulcerative colitis, systemic lupus erythematosus, depression, mood disorders and suicides (especially among women twenty-five years of age and younger, in the first six months of use), multiple sclerosis, interstitial cystitis, female sexual dysfunction, osteoporotic bone fractures (especially for progesterone-only contraceptives), and fatty weight gain. Misleading prescribing information regarding cardiovascular and thrombotic risks are also noted. Women seeking birth control have a right to be informed and educated about risk avoidance through the use of effective nonhormonal methods like fertility awareness methods. In one case-that of DMPA-the increased risk of HIV acquisition has been conclusively demonstrated to be both real and unique to this drug. Considering the availability of numerous alternatives, there is no justification for the continued marketing of DMPA to the public.

SUMMARY

We reviewed the effect of hormonal contraceptives on women's health. A number of potential side effects were noted including increased risks of breast cancer, cervical cancer, inflammatory bowel  disease, lupus, multiple sclerosis, cystitis, bone fractures, depression, mood disorders and suicides,  fatty weight gain, and female sexual dysfunction.  With the long-acting injectable contraceptives there is an increased risk of getting HIV.  Misleading prescribing information regarding the risks of heart attacks, strokes and blood clotting problems were also noted. Women seeking birth control have a right to know about how to avoid these risks by using effective hormone-free Fertility Awareness Methods.

Balance between Retroviral Latency and Transcription: Based on HIV Model

The representative of the Lentivirus genus is the human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome (AIDS). To date, there is no cure for AIDS because of the existence of the HIV-1 reservoir. HIV-1 infection can persist for decades despite effective antiretroviral therapy (ART), due to the persistence of infectious latent viruses in long-lived resting memory CD4+ T cells, macrophages, monocytes, microglial cells, and other cell types. However, the biology of HIV-1 latency remains incompletely understood. Retroviral long terminal repeat region (LTR) plays an indispensable role in controlling viral gene expression. Regulation of the transcription initiation plays a crucial role in establishing and maintaining a retrovirus latency. Whether and how retroviruses establish latency and reactivate remains unclear. In this article, we describe what is known about the regulation of LTR-driven transcription in HIV-1, that is, the cis-elements present in the LTR, the role of LTR transcription factor binding sites in LTR-driven transcription, the role of HIV-1-encoded transactivator protein, hormonal effects on virus transcription, impact of LTR variability on transcription, and epigenetic control of retrovirus LTR. Finally, we focus on a novel clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/dCas9)-based strategy for HIV-1 reservoir purging.

Cervical and systemic concentrations of long acting hormonal contraceptive (LARC) progestins depend on delivery method: Implications for the study of HIV transmission

Progestin-only long-acting reversible contraceptives (LARCs) are increasingly popular among women seeking contraception; however, recent epidemiological studies suggest that systemically administered medroxyprogesterone acetate (MPA) may increase HIV acquisition. In order to determine the exact mechanisms underlying increases in transmission specific to MPA use and to test safer, alternative contraceptive progestin types and delivery methods, in vitro modeling studies must be performed. To achieve this, it is imperative that accurate hormone concentrations be utilized when modeling progestin-mediated outcomes, as the down-stream effects are dose-dependent. The local concentrations of progestins to which the lower female genital tract tissues are exposed after initiation of LARCs are unknown, but they likely differ from peripheral concentrations, dependent upon the progestin type and delivery method. Here, we measured in vivo endocervical and plasma concentrations of (1) systemically-delivered depo MPA (DMPA), (2) levonorgestrel (LNG) delivered via intrauterine system (IUS) and (3) etonogestrel (ETG) delivered via vaginal ring in women who recently initiated contraception treatment. Levels of ETG and LNG in cervical secretions were 100-200 fold higher than plasma levels. In contrast, measurable MPA levels were approximately 10-fold higher in plasma compared to cervical secretions. These results will inform the design of accurate in vitro studies on the influence of progestins on epithelial cells, tissue explants, and peripheral blood cells, to be able to better predict in vivo outcomes. Subsequent observations will aid in determining how MPA might influence HIV acquisition and may facilitate identification of optimal progestin-containing LARC alternatives for women at high risk for HIV infection.

HIV-1 Latency Is Maintained by the Estrogen Receptor

Persistence of the latent reservoir remains a challenge to curing HIV infection. Using shRNA screening, new insights into the molecular mechanisms underlying latency regulation indicate that the estrogen receptor is a potent repressor of proviral reactivation and may serve as a promising therapeutic target in combination with other latency-reversing agents.

HIV and symptoms of depression are independently associated with impaired glucocorticoid signaling

Chronic inflammation caused by HIV infection may lead to deficient glucocorticoid (GC) signaling predisposing people living with HIV to depression and other psychiatric disorders linked to GC resistance. We hypothesized that comorbid HIV and depressive symptoms in women would synergistically associate with deficits in GC signaling. This cross-sectional study used samples obtained from the Women's Interagency HIV Study (WIHS). The Centers for Epidemiological Studies (CES-D) was used to define depression in four groups of women from the Women's Interagency HIV Study (WIHS): 1) HIV-negative, non-depressed (n = 37); 2) HIV-negative, depressed (n = 34); 3) HIV-positive, non-depressed (n = 38); and 4) HIV-positive, depressed (n = 38). To assess changes in GC signaling from peripheral blood mononuclear cells (PBMCs), we examined baseline and dexamethasone (Dex)-stimulated changes in the expression of the GC receptor (GR, gene: Nr3c1) and its negative regulator Fkbp5 via quantitative RT-PCR. GR sensitivity was evaluated in vitro by assessing the Dex inhibition of lipopolysaccharide (LPS)-stimulated IL-6 and TNF-α levels. Depressive symptoms and HIV serostatus were independently associated with elevated baseline expression of Fkbp5 and Nr3c1. Depressive symptoms, but not HIV status, was independently associated with reduced LPS-induced release of IL-6. Counter to predictions, there was no interactive association of depressive symptoms and HIV on any outcome. Comorbid depressive symptoms with HIV infection were associated with a gene expression and cytokine profile similar to that of healthy control women, a finding that may indicate further disruptions in disease adaptation.

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

Access to effective affordable contraception is critical for individual and public health. A wide range of hormonal contraceptives (HCs), which differ in composition, concentration of the progestin component, frequency of dosage, and method of administration, is currently available globally. However, the options are rather limited in settings with restricted economic resources that frequently overlap with areas of high HIV-1 prevalence. The predominant contraceptive used in sub-Saharan Africa is the progestin-only three-monthly injectable depot medroxyprogesterone acetate. Determination of whether HCs affect HIV-1 acquisition has been hampered by behavioral differences potentially confounding clinical observational data. Meta-analysis of these studies shows a significant association between depot medroxyprogesterone acetate use and increased risk of HIV-1 acquisition, raising important concerns. No association was found for combined oral contraceptives containing levonorgestrel, nor for the two-monthly injectable contraceptive norethisterone enanthate, although data for norethisterone enanthate are limited. Susceptibility to HIV-1 and other sexually transmitted infections may, however, be dependent on the type of progestin present in the formulation. Several underlying biological mechanisms that may mediate the effect of HCs on HIV-1 and other sexually transmitted infection acquisition have been identified in clinical, animal, and ex vivo studies. A substantial gap exists in the translation of basic research into clinical practice and public health policy. To bridge this gap, we review the current knowledge of underlying mechanisms and biological effects of commonly used progestins. The review sheds light on issues critical for an informed choice of progestins for the identification of safe, effective, acceptable, and affordable contraceptive methods.

Interplay between circadian clock and viral infection

The circadian clock underpins most physiological conditions and provides a temporal dimension to our understanding of body and tissue homeostasis. Disruptions of circadian rhythms have been associated with many diseases, including metabolic disorders and cancer. Recent literature highlights a role for the circadian clock to regulate innate and adaptive immune functions that may prime the host response to infectious organisms. Viruses are obligate parasites that rely on host cell synthesis machinery for their own replication, survival and dissemination. Here, we review key findings on how circadian rhythms impact viral infection and how viruses modulate molecular clocks to facilitate their own replication. This emerging area of viral-clock biology research provides a fertile ground for discovering novel anti-viral targets and optimizing immune-based therapies.

Glucocorticoid-independent modulation of GR activity: Implications for immunotherapy

Pharmacological doses of glucocorticoids (GCs), acting via the glucocorticoid receptor (GR) to repress inflammation and immune function, remain the most effective therapy in the treatment of inflammatory and immune diseases. Since many patients on GC therapy exhibit GC resistance and severe side-effects, much research is focused on developing more selective GCs and combination therapies, with greater anti-inflammatory potency. GCs mediate their classical genomic transcriptional effects by binding to the cytoplasmic GR, followed by nuclear translocation and modulation of transcription of target genes by direct DNA binding of the GR or its tethering to other transcription factors. Recent evidence suggests, however, that the responses mediated by the GR are much more complex and involve multiple parallel mechanisms integrating simultaneous signals from other receptors, both in the absence and presence of GCs, to shift the sensitivity of a target cell to GCs. The level of cellular stress, immune activation status, or the cell cycle phase may be crucial for determining GC sensitivity and GC responsiveness as well as subcellular localization of the GR and GR levels. Central to the development of new drugs that target GR signaling alone or as add-on therapies, is an in-depth understanding of the molecular mechanisms of GC-independent GR desensitization, priming and activation of the unliganded GR, as well as synergy and cross-talk with other signaling pathways. This review will discuss the information currently available on these topics and their relevance to immunotherapy, as well as identify unanswered questions and future areas of research.

Hormonal contraception and the risk of HIV acquisition: an individual participant data meta-analysis

BACKGROUND

Observational studies of a putative association between hormonal contraception (HC) and HIV acquisition have produced conflicting results. We conducted an individual participant data (IPD) meta-analysis of studies from sub-Saharan Africa to compare the incidence of HIV infection in women using combined oral contraceptives (COCs) or the injectable progestins depot-medroxyprogesterone acetate (DMPA) or norethisterone enanthate (NET-EN) with women not using HC.

METHODS AND FINDINGS

Eligible studies measured HC exposure and incident HIV infection prospectively using standardized measures, enrolled women aged 15-49 y, recorded ≥15 incident HIV infections, and measured prespecified covariates. Our primary analysis estimated the adjusted hazard ratio (aHR) using two-stage random effects meta-analysis, controlling for region, marital status, age, number of sex partners, and condom use. We included 18 studies, including 37,124 women (43,613 woman-years) and 1,830 incident HIV infections. Relative to no HC use, the aHR for HIV acquisition was 1.50 (95% CI 1.24-1.83) for DMPA use, 1.24 (95% CI 0.84-1.82) for NET-EN use, and 1.03 (95% CI 0.88-1.20) for COC use. Between-study heterogeneity was mild (I(2) < 50%). DMPA use was associated with increased HIV acquisition compared with COC use (aHR 1.43, 95% CI 1.23-1.67) and NET-EN use (aHR 1.32, 95% CI 1.08-1.61). Effect estimates were attenuated for studies at lower risk of methodological bias (compared with no HC use, aHR for DMPA use 1.22, 95% CI 0.99-1.50; for NET-EN use 0.67, 95% CI 0.47-0.96; and for COC use 0.91, 95% CI 0.73-1.41) compared to those at higher risk of bias (p(interaction) = 0.003). Neither age nor herpes simplex virus type 2 infection status modified the HC-HIV relationship.

CONCLUSIONS

This IPD meta-analysis found no evidence that COC or NET-EN use increases women's risk of HIV but adds to the evidence that DMPA may increase HIV risk, underscoring the need for additional safe and effective contraceptive options for women at high HIV risk. A randomized controlled trial would provide more definitive evidence about the effects of hormonal contraception, particularly DMPA, on HIV risk.

Genetic variation in the promoter region of pro-inflammatory cytokine TNF-α in perinatal HIV transmission from Mumbai, India

Various host factors such as cytokines and HLA, regulate the immune system and influence HIV transmission to infants exposed to HIV-1 through their mothers. Tumor Necrosis Factor Alpha (TNF-α) is a strong pro-inflammatory mediator and thought to influence vulnerability to HIV infection (and/or) transmission. Polymorphisms in regulatory regions are known to govern the production of this cytokine. However, the association of these variations in perinatal HIV transmission is yet to be established. Present study aimed to evaluate if polymorphisms in promoter region of TNF-α gene is associated with perinatal HIV transmission. With informed consent from parents, infants' blood was collected for HIV screening and SNPs analysis at 2 loci: TNF (rs1800629) and TNF (rs361525) using PCR-SSP method. HIV positive (n = 27) and negative (n = 54) children at the end of 18th month follow up were considered for this study. GG genotype, responsible for low expression of TNF (rs1800629) was significantly (p = 0.005) higher in uninfected children, while higher GA genotype frequency was observed in infected children. The 'G' allele frequency was significantly higher in negative children (p = 0.016). We conclude that genotypic variants of TNF (rs1800629) are a likely contributor to perinatal HIV transmission. This provides new insights in markers of differential susceptibility to perinatal HIV transmission.

Frienemies of infection: A chronic case of host nuclear receptors acting as cohorts or combatants of infection

Macrophages and dendritic cells provide critical effector functions to efficiently resist and promptly eliminate infection. Pattern recognition receptors signaling operative in these cell types is imperative for their innate properties. However, it is now emerging that besides these conventional signaling pathways, nuclear receptors coupled gene regulation and transrepression pathways assemble immune regulatory networks. A couple of these networks associated with members of nuclear receptor superfamily decide heterogeneity in macrophages and dendritic cells population and thereby play decisive role in determining protective immunity against bacteria, viruses, fungi, protozoa and helminths. Pathogens also direct shift in the expression of nuclear receptors and their target genes and this is proclaimed to be a sui generis mechanism whereby microbes disconnect the genomic component from the peripheral immune response. Many endogenous and synthetic nuclear receptor ligands have been tested in various in vitro and in vivo infection models to study their effect on pathogen burden. Here, we discuss current advances in our understanding of the composite interactions between nuclear receptor and pathogens and their implications on the causatum infectious diseases.

Modulation of the long terminal repeat promoter activity of small ruminant lentiviruses by steroids

Production and excretion of small ruminant lentiviruses (SRLVs) varies with the stage of the host reproductive cycle, suggesting hormonal involvement in this variation. Stress may also affect viral expression. To determine if hormones affect SRLV transcriptional activity, the expression of green fluorescent protein (GFP) driven by the promoters in the U3-cap region of the long terminal repeats (LTRs) of different strains of SRLV was assessed in cell culture. High concentrations of steroids (progesterone, cortisol and dehydroepiandrosterone) inhibited expression of GFP driven by SRLV promoters. This effect decreased in a dose-dependent manner with decreasing concentrations of steroids. In some strains, physiological concentrations of cortisol or dehydroepiandrosterone (DHEA) induced the expression of GFP above the baseline. There was strain variation in sensitivity to hormones, but this differed for different hormones. The presence of deletions and a 43 base repeat in the U3 region upstream of the TATA box of the LTR made strain EV1 less sensitive to DHEA. However, no clear tendencies or patterns were observed when comparing strains of different genotypes and/or subtypes, or those triggering different forms of disease.

Effect of progestins on immunity: medroxyprogesterone but not norethisterone or levonorgestrel suppresses the function of T cells and pDCs

OBJECTIVES

The potential effect of hormonal contraception on HIV-1 acquisition and transmission represents an important public health issue. Several observational studies have suggested an association between the use of hormonal contraception, in particular injectable depot medroxyprogesterone acetate (DMPA), and an increased risk of HIV-1 acquisition and transmission. We and others have previously demonstrated that DMPA acts as a potent inhibitor of innate and adaptive immune mechanisms. The study presented here addresses the immunomodulatory properties of several common progestins with a potential to replace DMPA.

STUDY DESIGN

To identify safe alternatives to DMPA, we tested the effect of commonly used progestins on the function of human primary T cells and plasmacytoid dendritic cells (pDCs) obtained from the blood of healthy premenopausal women.

RESULTS

Medroxyprogesterone acetate (MPA) inhibited the activation of T cells and pDCs in response to T cell receptor- and Toll-like receptor-mediated activation at physiological concentrations. Etonogestrel exerted a partial suppressive activity at high concentrations. In sharp contrast, norethisterone (NET) and levonorgestrel (LNG) did not exhibit detectable immunosuppressive activity.

CONCLUSION

Evidence indicating the immunosuppressive properties of DMPA strongly suggests that DMPA should be discontinued and replaced with other forms of long-term contraception. Since NET and LNG do not exert immunosuppressive properties at physiological concentrations, these progestins should be considered as alternative contraceptives for women at high risk for HIV-1 infection.

IMPLICATIONS

The presented data suggest that, at physiological levels, the progestins NET and LNG do not suppress cytokine production by immune cells and should be considered as alternatives to DMPA; however, more in vivo testing is needed to confirm this data.

The progestin-only contraceptive medroxyprogesterone acetate, but not norethisterone acetate, enhances HIV-1 Vpr-mediated apoptosis in human CD4+ T cells through the glucocorticoid receptor

The glucocorticoid receptor (GR) regulates several physiological functions, including immune function and apoptosis. The HIV-1 virus accessory protein, viral protein R (Vpr), can modulate the transcriptional response of the GR. Glucocorticoids (GCs) and Vpr have been reported to induce apoptosis in various cells, including T-cells. We have previously shown that the injectable contraceptive, medroxyprogesterone acetate (MPA) is a partial to full agonist for the GR, unlike norethisterone acetate (NET-A). We investigated the functional cross talk between the GR and Vpr in inducing apoptosis in CD4(+) T-cells, in the absence and presence of GCs and these progestins, as well as progesterone. By using flow cytometry, we show that, in contrast to NET-A and progesterone, the synthetic GR ligand dexamethasone (Dex), cortisol and MPA induce apoptosis in primary CD4(+) T-cells. Furthermore, the C-terminal part of the Vpr peptide, or HIV-1 pseudovirus, together with Dex or MPA further increased the apoptotic phenotype, unlike NET-A and progesterone. By a combination of Western blotting, PCR and the use of receptor- selective agonists, we provide evidence that the GR and the estrogen receptor are the only steroid receptors expressed in peripheral blood mononuclear cells. These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4(+) T-cells via the GR. We show that apoptotic induction involves differential expression of key apoptotic genes by both Vpr and GCs/MPA. This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4(+) T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency. The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1.

Hormonal contraception and HIV-1 infection: medroxyprogesterone acetate suppresses innate and adaptive immune mechanisms

Recent observational studies indicate an association between the use of hormonal contraceptives and acquisition and transmission of HIV-1. The biological and immunological mechanisms underlying the observed association are unknown. Depot medroxyprogesterone acetate (DMPA) is a progestin-only injectable contraceptive that is commonly used in regions with high HIV-1 prevalence. Here we show that medroxyprogesterone acetate (MPA) suppresses the production of key regulators of cellular and humoral immunity involved in orchestrating the immune response to invading pathogens. MPA inhibited the production of interferon (IFN)-γ, IL-2, IL-4, IL-6, IL-12, TNFα, macrophage inflammatory protein-1α (MIP-1α), and other cytokines and chemokines by peripheral blood cells and activated T cells and reduced the production of IFNα and TNFα by plasmacytoid dendritic cells in response to Toll-like receptor-7, -8, and -9 ligands. Women using DMPA displayed lower levels of IFNα in plasma and genital secretions compared with controls with no hormonal contraception. In addition, MPA prevented the down-regulation of HIV-1 coreceptors CXCR4 and CCR5 on the surface of T cells after activation and increased HIV-1 replication in activated peripheral blood mononuclear cell cultures. The presented results suggest that MPA suppresses both innate and adaptive arms of the immune system resulting in a reduction of host resistance to invading pathogens.