Plasma concentrations of transforming growth factor beta 1 in non-progressive HIV-1 infection correlates with markers of disease progression

Precision Phenotyping of Heart Failure in People with HIV: Early Insights and Challenges

PURPOSE OF REVIEW

People with HIV have an elevated risk of developing heart failure even with optimally controlled disease. In this review, we outline the various mechanisms through which HIV infection may directly and indirectly contribute to heart failure pathology and highlight the emerging relationship between HIV, chronic inflammation, and cardiometabolic disease.

RECENT FINDINGS

HIV infection leads to chronic inflammation, immune dysregulation, and metabolic imbalances even in those with well controlled disease. These dysregulations occur through several diverse mechanisms which may lead to manifestations of different phenotypes of heart failure in people with HIV. While it has long been known that people with HIV are at risk of developing heart failure, recent studies have suggested numerous complex mechanisms involving chronic inflammation, immune dysregulation, and metabolic derangement through which this may be mediated. Further comprehensive studies are needed to elucidate the precise relationship between these mechanisms and the development of different subtypes of heart failure in people with HIV.

Post-Transcriptional HIV-1 Latency: A Promising Target for Therapy?

Human Immunodeficiency Virus type 1 (HIV-1) latency represents a significant hurdle in finding a cure for HIV-1 infections, despite tireless research efforts. This challenge is partly attributed to the intricate nature of HIV-1 latency, wherein various host and viral factors participate in multiple physiological processes. While substantial progress has been made in discovering therapeutic targets for HIV-1 transcription, targets for the post-transcriptional regulation of HIV-1 infections have received less attention. However, cumulative evidence now suggests the pivotal contribution of post-transcriptional regulation to the viral latency in both in vitro models and infected individuals. In this review, we explore recent insights on post-transcriptional latency in HIV-1 and discuss the potential of its therapeutic targets, illustrating some host factors that restrict HIV-1 at the post-transcriptional level.

Transforming Growth Factor β Signaling Promotes HIV-1 Infection in Activated and Resting Memory CD4+ T Cells

Understanding the facilitator of HIV-1 infection and subsequent latency establishment may aid the discovery of potential therapeutic targets. Here, we report the elevation of plasma transforming growth factor β (TGF-β) during acute HIV-1 infection among men who have sex with men (MSM). Using a serum-free in vitro system, we further delineated the role of TGF-β signaling in mediating HIV-1 infection of activated and resting memory CD4+ T cells. TGF-β could upregulate both the frequency and expression of the HIV-1 coreceptor CCR5, thereby augmenting CCR5-tropic viral infection of resting and activated memory CD4+ T cells via Smad3 activation. The production of live HIV-1JR-FL upon infection and reactivation was increased in TGF-β-treated resting memory CD4+ T cells without increasing CD4 expression or inducing T cell activation. The expression of CCR7, a central memory T cell marker that serves as a chemokine receptor to facilitate T cell trafficking into lymphoid organs, was also elevated on TGF-β-treated resting and activated memory CD4+ T cells. Moreover, the expression of CXCR3, a chemokine receptor recently reported to facilitate CCR5-tropic HIV-1 infection, was increased on resting and activated memory CD4+ T cells upon TGF-β treatment. These findings were coherent with the observation that ex vivo CCR5 and CXCR3 expression on total resting and resting memory CD4+ T cells in combination antiretroviral therapy (cART)-naive and cART-treated patients were higher than in healthy individuals. Overall, the study demonstrated that TGF-β upregulation induced by acute HIV-1 infection might promote latency reservoir establishment by increasing infected resting memory CD4+ T cells and lymphoid organ homing of infected central memory CD4+ T cells. Therefore, TGF-β blockade may serve as a potential supplementary regimen for HIV-1 functional cure by reducing viral latency. IMPORTANCE Incomplete eradication of HIV-1 latency reservoirs remains the major hurdle in achieving a complete HIV/AIDS cure. Dissecting the facilitator of latency reservoir establishment may aid the discovery of druggable targets for HIV-1 cure. This study showed that the T cell immunomodulatory cytokine TGF-β was upregulated during the acute phase of infection. Using an in vitro serum-free system, we specifically delineated that TGF-β promoted HIV-1 infection of both resting and activated memory CD4+ T cells via the induction of host CCR5 coreceptor. Moreover, TGF-β-upregulated CCR7 or CXCR3 might promote HIV-1 latent infection by facilitating lymphoid homing or IP-10-mediated viral entry and DNA integration, respectively. Infected resting and central memory CD4+ T cells are important latency reservoirs. Increased infection of these cells mediated by TGF-β will promote latency reservoir establishment during early infection. This study, therefore, highlighted the potential use of TGF-β blockade as a supplementary regimen with cART in acute patients to reduce viral latency.

Blockade of TGF-β signaling reactivates HIV-1/SIV reservoirs and immune responses in vivo

TGF-β plays a critical role in maintaining immune cells in a resting state by inhibiting cell activation and proliferation. Resting HIV-1 target cells represent the main cellular reservoir after long-term antiretroviral therapy (ART). We hypothesized that releasing cells from TGF-β-driven signaling would promote latency reversal. To test our hypothesis, we compared HIV-1 latency models with and without TGF-β and a TGF-β type 1 receptor inhibitor, galunisertib. We tested the effect of galunisertib in SIV-infected, ART-treated macaques by monitoring SIV-env expression via PET/CT using the 64Cu-DOTA-F(ab')2 p7D3 probe, along with plasma and tissue viral loads (VLs). Exogenous TGF-β reduced HIV-1 reactivation in U1 and ACH-2 models. Galunisertib increased HIV-1 latency reversal ex vivo and in PBMCs from HIV-1-infected, ART-treated, aviremic donors. In vivo, oral galunisertib promoted increased total standardized uptake values in PET/CT images in gut and lymph nodes of 5 out of 7 aviremic, long-term ART-treated, SIV-infected macaques. This increase correlated with an increase in SIV RNA in the gut. Two of the 7 animals also exhibited increases in plasma VLs. Higher anti-SIV T cell responses and antibody titers were detected after galunisertib treatment. In summary, our data suggest that blocking TGF-β signaling simultaneously increases retroviral reactivation events and enhances anti-SIV immune responses.

CMV and EBV Co-Infection in HIV-Infected Children: Infection Rates and Analysis of Differential Expression of Cytokines in HIV Mono- and HIV-CMV-EBV Co-Infected Groups

(1) Background: CMV and EBV co-infections can affect the HIV disease progression by modulating the immune system. The disease dynamics can differ in HIV-positive adults and children. In Pakistan, HIV is rapidly expanding, especially in children; however, the prevalence of CMV and EBV co-infection and the effect on immune modulation in HIV-positive children are not known. This study aimed to bridge this gap by estimating the rate of active CMV and EBV co-infection in HIV-positive children, followed by the analysis of differential expression of cytokines in HIV mono- and HIV/CMV/EBV co-infected children. (2) Methods: DNA samples from 319 HIV-positive children, previously recruited as part of a study to investigate the HIV outbreak in Larkana, Pakistan, in 2019, were screened for CMV and EBV through qPCR. Subsequently, differences in HIV viral loads and CD4 counts were analyzed between the HIV mono- and HIV/CMV/EBV co-infected groups. The RNA samples were used to determine the differential expression of both pro- and anti-inflammatory cytokines in the mono- and co-infected groups using RT-qPCR, while unpaired T-test and Pearson correlation test were applied to, respectively, analyze the differential cytokine expression and correlation between cytokine in the two groups. (3) Results: Of 319 samples, the rate of active EBV and CMV co-infection in HIV-positive children was observed in 79.9% and 38.9%, respectively. A significant difference was observed in HIV viral load between HIV mono- and co-infected groups. IFN-γ expression was found to be lower in the HIV mono-infected group, while higher in all other three co-infected groups. Meanwhile, mRNA expression of TGF-β1 was found to be lower in HIV mono- and HIV–CMV–EBV co-infected groups, while higher in HIV–CMV and HIV–EBV co-infected groups. IFN-γ and IL-2 exhibited a significant positive correlation in all except HIV–CMV co-infected group. (4) Conclusions: The study suggests that the presence of EBV/CMV co-infection can affect the HIV viral loads and expression of certain cytokines (IFN-γ and TGF-β1), which may affect the HIV disease dynamics in infected children.

Negative Regulation and Protective Function of Natural Killer Cells in HIV Infection: Two Sides of a Coin

Natural killer (NK) cells play an important immunologic role, targeting tumors and virus-infected cells; however, NK cells do not impede the progression of human immunodeficiency virus (HIV) infection. In HIV infection, NK cells exhibit impaired functions and negatively regulate other immune cell responses, although NK cells can kill HIV-infected cells and thereby suppress HIV replication. Considerable recent research has emerged regarding NK cells in the areas of immune checkpoints, negative regulation, antibody-dependent cell-mediated cytotoxicity and HIV reservoirs during HIV infection; however, no overall summary of these factors is available. This review focuses on several important aspects of NK cells in relation to HIV infection, including changes in NK cell count, subpopulations, and immune checkpoints, as well as abnormalities in NK cell functions and NK cell negative regulation. The protective function of NK cells in inhibiting HIV replication to reduce the viral reservoir and approaches for enhancing NK cell functions are also summarized.

Pulmonary Immune Dysregulation and Viral Persistence During HIV Infection

Despite the success of antiretroviral therapy (ART), people living with HIV continue to suffer from high burdens of respiratory infections, lung cancers and chronic lung disease at a higher rate than the general population. The lung mucosa, a previously neglected HIV reservoir site, is of particular importance in this phenomenon. Because ART does not eliminate the virus, residual levels of HIV that remain in deep tissues lead to chronic immune activation and pulmonary inflammatory pathologies. In turn, continuous pulmonary and systemic inflammation cause immune cell exhaustion and pulmonary immune dysregulation, creating a pro-inflammatory environment ideal for HIV reservoir persistence. Moreover, smoking, gut and lung dysbiosis and co-infections further fuel the vicious cycle of residual viral replication which, in turn, contributes to inflammation and immune cell proliferation, further maintaining the HIV reservoir. Herein, we discuss the recent evidence supporting the notion that the lungs serve as an HIV viral reservoir. We will explore how smoking, changes in the microbiome, and common co-infections seen in PLWH contribute to HIV persistence, pulmonary immune dysregulation, and high rates of infectious and non-infectious lung disease among these individuals.

Inhibition of miR-155 Promotes TGF-β Mediated Suppression of HIV Release in the Cervical Epithelial Cells

TGF-β has been shown to play a differential role in either restricting or aiding HIV infection in different cell types, however its role in the cervical cells is hitherto undefined. Among females, more than 80% of infections occur through heterosexual contact where cervicovaginal mucosa plays a critical role, however the early events during the establishment of infection at female genital mucosa are poorly understood. We earlier showed that increased TGF-β level has been associated with cervical viral shedding in the HIV infected women, however a causal relationship could not be examined. Therefore, here we first established an in vitro cell-associated model of HIV infection in the cervical epithelial cells (ME-180) and demonstrated that TGF-β plays an important role as a negative regulator of HIV release in the infected cervical epithelial cells. Inhibition of miR-155 upregulated TGF-β signaling and mRNA expression of host restriction factors such as APOBEC-3G, IFI-16 and IFITM-3, while decreased the HIV release in ME-180 cells. To conclude, this is the first study to decipher the complex interplay between TGF-β, miR-155 and HIV release in the cervical epithelial cells. Collectively, our data suggest the plausible role of TGF-β in promoting HIV latency in cervical epithelial cells which needs further investigations.

The multi-faceted roles of TGF-β in regulation of immunity to infection

Transforming Growth Factor-β is a potent regulator of the immune system, acting at every stage from thymic differentiation, population of the periphery, control of responsiveness, tissue repair and generation of memory. It is therefore a central player in the immune response to infectious pathogens, but its contribution is often clouded by multiple roles acting on different cells in time and space. Hence, context is all-important in understanding when TGF-β is beneficial or detrimental to the outcome of infection. In this review, a full range of infectious agents from viruses to helminth parasites are explored within this framework, drawing contrasts and general conclusions about the importance of TGF-β in these diseases.

Ultrasensitive Detection of p24 in Plasma Samples from People with Primary and Chronic HIV-1 Infection

HIV-1 Gag p24 has long been identified as an informative biomarker of HIV replication, disease progression, and therapeutic efficacy, but the lower sensitivity of immunoassays in comparison to molecular tests and the interference with antibodies in chronic HIV infection limit its application for clinical monitoring. The development of ultrasensitive protein detection technologies may help in overcoming these limitations. Here, we evaluated whether immune complex dissociation combined with ultrasensitive digital enzyme-linked immunosorbent assay (ELISA) single-molecule array (Simoa) technology could be used to quantify p24 in plasma samples from people with HIV-1 infection. We found that, among different immune complex dissociation methods, only acid-mediated dissociation was compatible with ultrasensitive p24 quantification by digital ELISA, strongly enhancing p24 detection at different stages of HIV-1 infection. We show that ultrasensitive p24 levels correlated positively with plasma HIV RNA and HIV DNA and negatively with CD4-positive (CD4⁺) T cells in the samples from people with primary and chronic HIV-1 infection. In addition, p24 levels also correlated with plasma D-dimers and interferon alpha (IFN-α) levels. p24 levels sharply decreased to undetectable levels after initiation of combined antiretroviral treatment (cART). However, we identified a group of people who, 48 weeks after cART initiation, had detectable p24 levels despite most having undetectable viral loads. These people had different virological and immunological baseline characteristics compared with people who had undetectable p24 after cART. These results demonstrate that ultrasensitive p24 analysis provides an efficient and robust means to monitor p24 antigen in plasma samples from people with HIV-1 infection, including during antiretroviral treatment, and may provide complementary information to other commonly used biomarkers. IMPORTANCE The introduction of combined antiretroviral treatment has transformed HIV-1 infection into a manageable condition. In this context, there is a need for additional biomarkers to monitor HIV-1 residual disease or the outcome of new interventions, such as in the case of HIV cure strategies. The p24 antigen has a long half-life outside viral particles, and it is, therefore, a very promising marker to monitor episodes of viral replication or transient activation of the viral reservoir. However, the formation of immune complexes with anti-p24 antibodies makes its quantification difficult beyond acute HIV-1 infection. We show here that, upon immune complex dissociation, new technologies allow the ultrasensitive p24 quantification in plasma samples throughout HIV-1 infection at levels close to those of viral RNA and DNA determinations. Our results further indicate that ultrasensitive p24 quantification may have added value when used in combination with other classic clinical biomarkers.

Enhanced Intestinal TGF-β/SMAD-Dependent Signaling in Simian Immunodeficiency Virus Infected Rhesus Macaques

Transforming growth factor-β signaling (TGF-β) maintains a balanced physiological function including cell growth, differentiation, and proliferation and regulation of immune system by modulating either SMAD2/3 and SMAD7 (SMAD-dependent) or SMAD-independent signaling pathways under normal conditions. Increased production of TGF-β promotes immunosuppression in Human Immunodeficiency Virus (HIV)/Simian Immunodeficiency Virus (SIV) infection. However, the cellular source and downstream events of increased TGF-β production that attributes to its pathological manifestations remain unknown. Here, we have shown increased production of TGF-β in a majority of intestinal CD3⁻CD20⁻CD68⁺ cells from acute and chronically SIV infected rhesus macaques, which negatively correlated with the frequency of jejunum CD4⁺ T cells. No significant changes in intestinal TGF-β receptor II expression were observed but increased production of the pSMAD2/3 protein and SMAD3 gene expression in jejunum tissues that were accompanied by a downregulation of SMAD7 protein and gene expression. Enhanced TGF-β production by intestinal CD3⁻CD20⁻CD68⁺ cells and increased TGF-β/SMAD-dependent signaling might be due to a disruption of a negative feedback loop mediated by SMAD7. This suggests that SIV infection impacts the SMAD-dependent signaling pathway of TGF-β and provides a potential framework for further study to understand the role of viral factor(s) in modulating TGF-β production and downregulating SMAD7 expression in SIV. Regulation of mucosal TGF-β expression by therapeutic TGF-β blockers may help to create effective antiviral mucosal immune responses.

Immune Dysregulation in Myocardial Fibrosis, Steatosis, and Heart Failure: Current Insights from HIV and the General Population

PURPOSE OF REVIEW

HIV is an independent risk factor for heart failure (HF). Cardiac imaging studies in people with HIV (PWH) have identified myocardial pathologies, namely fibrosis and steatosis, that likely contribute to the higher risk of HF. In this review, we survey existing epidemiological, clinical, and mechanistic literature to identify potential pathways that may contribute to the burden of myocardial fibrosis and steatosis among PWH.

RECENT FINDINGS

Multiple cohort studies over the past 20 years have demonstrated a roughly 2-fold higher risk of incident HF in PWH, as well as a disproportionate burden of myocardial fibrosis and steatosis in PWH without HF. Both myocardial fibrosis and steatosis are known contributors to HF in adults without HIV. Pathways involving the NLRP3 inflammasome, TGF-β1, and adipocyte dysfunction are known to play a crucial role in the development of myocardial fibrosis and steatosis. Upregulation of these pathways in HIV due to direct effects of viral proteins, persistent immune dysregulation, gut epithelial breakdown and dysbiosis, and toxicities from antiretroviral therapy may contribute to myocardial dysfunction in HIV. Understanding these pathways may lead to more precise diagnostic and therapeutic targets to curb HF in PWH. During the past three decades, observational and mechanistic studies have provided important insights into risk factors and pathways that may contribute to the increased HF risk in PWH. Future work is needed to characterize these pathways more precisely in mechanistic studies of PWH, with the goal of ultimately deriving valuable targets for prevention, early diagnosis, and treatment of HF in PWH.

Dynamics of Transforming Growth Factor (TGF)-β Superfamily Cytokine Induction During HIV-1 Infection Are Distinct From Other Innate Cytokines

Human immunodeficiency virus type 1 (HIV-1) infection triggers rapid induction of multiple innate cytokines including type I interferons, which play important roles in viral control and disease pathogenesis. The transforming growth factor (TGF)-β superfamily is a pleiotropic innate cytokine family, some members of which (activins and bone morphogenetic proteins (BMPs)) were recently demonstrated to exert antiviral activity against Zika and hepatitis B and C viruses but are poorly studied in HIV-1 infection. Here, we show that TGF-β₁ is systemically induced with very rapid kinetics (as early as 1-4 days after viremic spread begins) in acute HIV-1 infection, likely due to release from platelets, and remains upregulated throughout infection. Contrastingly, no substantial systemic upregulation of activins A and B or BMP-2 was observed during acute infection, although plasma activin levels trended to be elevated during chronic infection. HIV-1 triggered production of type I interferons but not TGF-β superfamily cytokines from plasmacytoid dendritic cells (DCs) in vitro, putatively explaining their differing in vivo induction; whilst lipopolysaccharide (but not HIV-1) elicited activin A production from myeloid DCs. These findings underscore the need for better definition of the protective and pathogenic capacity of TGF-β superfamily cytokines, to enable appropriate modulation for therapeutic purposes.

Cenicriviroc, a dual CCR2 and CCR5 antagonist leads to a reduction in plasma fibrotic biomarkers in persons living with HIV on antiretroviral therapy

Background: Chronic HIV is associated with increased inflammation and tissue fibrosis despite suppressive antiretroviral therapy (ART). Monocytes and macrophages have been implicated in the pathogenesis of fibrosis, facilitated by chemokine receptor interactions.Methods: We assessed systemic fibrotic biomarkers (transforming growth factor beta-1 [TGF-β1], thrombospondin-1 [TSP-1], C-terminal pro-peptide of collagen type I [CICP], and IL-11) in banked plasma from a previously published 24-week open-label trial of cenicriviroc (CVC), a dual CCR2/CCR5 antagonist, among persons living with HIV (PLWH) on stable ART with undetectable plasma HIV RNA (<50 copies/mL). Fibrotic markers were assessed by ELISA and Luminex. Untreated HIV-seronegative individuals (n = 6) of similar age and demographics served as a comparator group.Results: Median age of PLWH was 55 years. At baseline, PLWH had higher median TGF-β1 (2.11 vs 1.62 ng/mL, p = 0.01), TSP-1 (236.74 vs 83.29 ng/mL, p < 0.0001), and CICP (200.46 vs 111.28 ng/mL, p = 0.01), but lower IL-11 (36.00 vs 53.74 pg/mL, p = 0.01) compared to HIV-uninfected individuals. Over 24 weeks, median TGF-β1 (-0.74 ng/mL, p = 0.006), TSP-1 (-52.12 ng/mL, p < 0.0001), and CICP (-28.12 ng/mL, p < 0.0001) decreased and IL-11 (28.98 pg/mL, p < 0.0001) increased in PLWH. At week 24, TGF-β1, CICP, and IL-11 were similar between the two groups (p > 0.05), while TSP-1 remained elevated in PLWH (p = 0.009) compared to controls.Conclusions: PLWH had higher levels of the plasma fibrotic markers TGF-β1, TSP-1, and CICP. After 24 weeks of CVC, fibrotic markers generally returned to levels comparable to HIV-uninfected controls. Dual CCR2 and CCR5 blockade may ameliorate the detrimental fibrotic events that persist in treated HIV.

High resistance to reverse transcriptase inhibitors among persons infected with human immunodeficiency virus type 1 subtype circulating recombinant form 02_AG in Ghana and on antiretroviral therapy

This study sought to determine the dominant circulating human immunodeficiency virus type 1 (HIV-1) subtype and associated drug resistance mutations in Ghana.This cross-sectional study was conducted with archived samples collected from patients who received care at 2 hospitals in Ghana from 2014 to 2016. Blood samples were earlier processed into plasma and peripheral blood mononuclear cells and stored at -80 °C. Ribonucleic acid (RNA) was extracted from the archived plasma. Two HIV-1 genes; protease and reverse transcriptase, were amplified, sequenced using gene-specific primers and analyzed for subtype and drug resistance mutations using the Stanford HIV Database.Of 16 patient samples successfully sequenced, we identified the predominance of HIV-1 subtype CRF02_AG (11/16, 68%). Subtypes G (2/16, 13%), dual CRF02_AG/G (2/16, 13%), and CRF01_AE (1/16, 6%) were also observed. Major nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations, M184I/V, D67N, T215F, and K70R/E were found. Non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations, K103N, Y181C, V90I, F227L, and V106A were also prevalent. Additionally, and at a lower level, protease inhibitor (PI)-resistance mutations, M46I, I54 V, V82A, L90 M, and I471 V, were also present in the sequences from antiretroviral therapy (ART)-experienced individuals. Two NRTI-associated drug resistance mutations (DRMs) (D67N and T69N) were present in sequences from 1 ART-naive individual.HIV-1 subtype CRF02_AG was most frequently detected in this study thus confirming earlier reports of dominance of this subtype in the West-African sub-region and Ghana in particular. The detection of these drug resistance mutations in individuals on first-line regimen composed of NRTI and NNRTI is an indication of prolonged drug exposure without viral load monitoring. Routine viral load monitoring is necessary for early detection of virologic failure and drug resistance testing will inform appropriate choice of regimens for such patients.

Effects of Tobacco Usage and Antiretroviral Therapy on Biomarkers of Systemic Immune Activation in HIV-Infected Participants

Like HIV infection, smoking, which is common among HIV-infected persons, is associated with chronic, systemic inflammation. However, the possible augmentative effects of HIV infection and smoking and other types of tobacco usage on indices of systemic inflammation and the impact of combination antiretroviral therapy (cART) thereon remain largely unexplored and represent the focus of the current study. Of the total number of HIV-infected persons recruited to the study (n = 199), 100 were categorised as pre-cART and 99 as virally suppressed (HIV viral load < 40 copies/mL). According to serum cotinine levels, 144 and 55 participants were categorised as nonusers and users of tobacco, respectively. In addition to cytokines (IL-6, IL-8, and TNF-α) and chemokines (IP-10, MIG, IL-8, MCP-1, and RANTES), other biomarkers of systemic inflammation included C-reactive protein (CRP), β2-microglobulin, and those of neutrophil activation [ICAM-1, L-selectin, matrix metalloproteinase-9 (MMP-9)], microbial translocation (soluble CD14, LPS-binding protein), and oxidative stress (cyclophilin A, surfactant D). These were measured using multiplex bead array, ELISA, and immunonephelometric procedures. Viral suppression was associated with significant decreases in the levels of most of the biomarkers tested (P < 0.0037-0.0008), with the exceptions of CRP, cyclophilin A, and MMP-9. With respect to tobacco usage, irrespective of cART status, circulating levels of β2-microglobulin, cyclophilin A, and RANTES were significantly elevated (P < 0.042-0.012) in users vs nonusers. Additional analysis of the groups of tobacco users and nonusers according to cART status revealed high levels of RANTES in pre-cART/tobacco users relative to the three other subgroups (P < 0.004-0.0001), while more modest increases in cyclophilin A and MMP-9 (P < 0.019-0.027) were observed in comparison with the cART/tobacco user subgroup. Notwithstanding the efficacy of cART in attenuating HIV-associated, chronic systemic inflammation, the current study has identified RANTES as being significantly and seemingly selectively increased in those with active HIV infection who use tobacco, a mechanism which may underpin augmentative proinflammatory activity.

Detection of HIV-1 and Human Proteins in Urinary Extracellular Vesicles from HIV+ Patients

BACKGROUND

Extracellular vesicles (EVs) are membrane bound, secreted by cells, and detected in bodily fluids, including urine, and contain proteins, RNA, and DNA. Our goal was to identify HIV and human proteins (HPs) in urinary EVs from HIV+ patients and compare them to HIV- samples.

METHODS

Urine samples were collected from HIV+ (n = 35) and HIV- (n = 12) individuals. EVs were isolated by ultrafiltration and characterized using transmission electron microscopy, tandem mass spectrometry (LC/MS/MS), and nanoparticle tracking analysis (NTA). Western blots confirmed the presence of HIV proteins. Gene ontology (GO) analysis was performed using FunRich and HIV Human Interaction database (HHID).

RESULTS

EVs from urine were 30-400 nm in size. More EVs were in HIV+ patients, P < 0.05, by NTA. HIV+ samples had 14,475 HPs using LC/MS/MS, while only 111 were in HIV-. HPs in the EVs were of exosomal origin. LC/MS/MS showed all HIV+ samples contained at least one HIV protein. GO analysis showed differences in proteins between HIV+ and HIV- samples and more than 50% of the published HPs in the HHID interacted with EV HIV proteins.

CONCLUSION

Differences in the proteomic profile of EVs from HIV+ versus HIV- samples were found. HIV and HPs in EVs could be used to detect infection and/or diagnose HIV disease syndromes.

Viruses as key modulators of the TGF-β pathway; a double-edged sword involved in cancer

Transforming growth factor-β (TGF-β) signaling pathway is a key network in cell signaling that controls vital processes such as proliferation, differentiation, apoptosis, epithelial-mesenchymal transition, and migration, thus acting as a double-edged sword in normal development and diseases, in particular organ fibrosis, vascular disorders, and cancer. Early in tumorigenesis, the pathway exerts anti-tumor effects through suppressing cell cycle and inducing apoptosis, while during late stages, it functions as a tumor promoter by enhancing tumor invasiveness and metastasis. This signaling pathway can be perturbed by environmental and genetic factors such as microbial interference and mutation, respectively. In this way, the present review describes the modulation of the TGF-β pathway by oncogenic human viral pathogens and other viruses. The main mechanisms by which viruses interferes with TGF-β signaling seems to be through (1) the alteration of either TGF-β protein expression or activation, (2) the modulation of the TGF-β receptors or SMADs factors (by interfering with their levels and functions), (3) the alteration of none-SMAD pathways, and (4) indirect interaction with the pathway by the modulation of transcriptional co-activator/repressor and regulators of the pathway. Given the axial role of this pathway in tumorigenesis, it can be regarded as an attractive target for cancer therapy. Hence, further investigations on this subject may represent molecular targets among either TGF-β signaling molecules or viral factors for the treatment and management of viral infection consequences such as cancer.

The Role of Transforming Growth Factor Beta-1 in the Progression of HIV/AIDS and Development of Non-AIDS-Defining Fibrotic Disorders

Even after attainment of sustained viral suppression following implementation of highly active antiretroviral therapy, HIV-infected persons continue to experience persistent, low-grade, systemic inflammation. Among other mechanisms, this appears to result from ongoing microbial translocation from a damaged gastrointestinal tract. This HIV-related chronic inflammatory response is paralleled by counteracting, but only partially effective, biological anti-inflammatory processes. Paradoxically, however, this anti-inflammatory response not only exacerbates immunosuppression but also predisposes for development of non-AIDS-related, non-communicable disorders. With respect to the pathogenesis of both sustained immunosuppression and the increased frequency of non-AIDS-related disorders, the anti-inflammatory/profibrotic cytokine, transforming growth factor-β1 (TGF-β1), which remains persistently elevated in both untreated and virally suppressed HIV-infected persons, may provide a common link. In this context, the current review is focused on two different, albeit related, harmful activities of TGF-β1 in HIV infection. First, on the spectrum of anti-inflammatory/immunosuppressive activities of TGF-β1 and the involvement of this cytokine, derived predominantly from T regulatory cells, in driving disease progression in HIV-infected persons via both non-fibrotic and profibrotic mechanisms. Second, the possible involvement of sustained elevations in circulating and tissue TGF-β1 in the pathogenesis of non-AIDS-defining cardiovascular, hepatic, pulmonary and renal disorders, together with a brief comment on potential TGF-β1-targeted therapeutic strategies.

IL-7 and CD4 T Follicular Helper Cells in HIV-1 Infection

IL-7 was previously shown to upregulate the expression of molecules important for interaction of CD4+ T cells with B cells. It is poorly studied whether IL-7 has a role in the biology of T follicular helper (Tfh) cells and whether IL-7 dysregulates the expression of B-cell costimulatory molecules on Tfh cells. We review the literature and provide arguments in favor of IL-7 being involved in the biology of human Tfh cells. The CD127 IL-7 receptor is expressed on circulating Tfh and non-Tfh cells, and we show that IL-7, but not IL-6 or IL-21, upregulates the expression of CD70 and PD-1 on these cells. We conclude that IL-7, a cytokine whose level is elevated during HIV-1 infection, may have a role in increased expression of B cell costimulatory molecules on Tfh cells and lead to abnormal B cell differentiation.

Mucosal Regulatory T Cells and T Helper 17 Cells in HIV-Associated Immune Activation

Residual mucosal inflammation along with chronic systemic immune activation is an important feature in individuals infected with human immunodeficiency virus (HIV), and has been linked to a wide range of co-morbidities, including malignancy, opportunistic infections, immunopathology, and cardiovascular complications. Although combined antiretroviral therapy (cART) can reduce plasma viral loads to undetectable levels, reservoirs of virus persist, and increased mortality is associated with immune dysbiosis in mucosal lymphoid tissues. Immune-based therapies are pursued with the goal of improving CD4⁺ T-cell restoration, as well as reducing chronic immune activation in cART-treated patients. However, the majority of research on immune activation has been derived from analysis of circulating T cells. How immune cell alterations in mucosal tissues contribute to HIV immune dysregulation and the associated risk of non-infectious chronic complications is less studied. Given the significant differences between mucosal T cells and circulating T cells, and the immediate interactions of mucosal T cells with the microbiome, more attention should be devoted to mucosal immune cells and their contribution to systemic immune activation in HIV-infected individuals. Here, we will focus on mucosal immune cells with a specific emphasis on CD4⁺ T lymphocytes, such as T helper 17 cells and CD4⁺Foxp3⁺ regulatory T cells (T_regs), which play crucial roles in maintaining mucosal barrier integrity and preventing inflammation, respectively. We hypothesize that pro-inflammatory milieu in cART-treated patients with immune activation significantly contributes to enhanced loss of Th17 cells and increased frequency of dysregulated T_regs in the mucosa, which in turn may exacerbate immune dysfunction in HIV-infected patients. We also present initial evidence to support this hypothesis. A better comprehension of how pro-inflammatory milieu impacts these two types of cells in the mucosa will shed light on mucosal immune dysfunction and HIV reservoirs, and lead to novel ways to restore immune functions in HIV⁺ patients.