Monocytes/macrophages are innate immune cells that play a crucial role in the resolution of inflammation. In presence of Th2 cytokines interleukin-4 (IL-4) and interleukin-13 (IL-13), they display an anti-inflammatory profile and this activation pathway is known as alternative activation. In this study we compare and differentiate pathways mediated by IL-4 and IL-13 activation of human monocytes/macrophage. Here we report differential regulation of IL-4 and IL-13 signaling in monocytes/macrophages starting from IL-4/IL-13 cytokine receptors to Jak-Stat-mediated signaling pathways that ultimately control expression of several infl1ammatory genes. Our data demonstrate that while the receptor-associated tyrosine kinases Jak2 and Tyk2 are activated after the recruitment of IL-13 to its receptor (containing IL-4Rα and IL-13Rα1), IL-4 stimulates Jak1 activation. We further show that Jak2 is upstream of Stat3 activation and Tyk2 controls Stat1 and Stat6 activation in response to IL-13 stimulation. In contrast, Jak1 regulates Stat3 and Stat6 activation in IL-4-induced monocytes. Our results further reveal that while IL-13 utilizes both IL-4Rα-Jak2-Stat3 and IL-13Rα1-Tyk2-Stat1/Stat6 signaling pathways, IL-4 can only use the IL-4Rα-Jak1-Stat3/Stat6 cascade to regulate the expression of some critical inflammatory genes including 15-lipoxygenase (15-LO), monoamine oxidase A (MAO-A) and scavenger receptor CD36. Moreover, we demonstrate here that IL-13 and IL-4 can uniquely affect the expression of particular genes like dual specificity phosphatase 1 (DUSP1) and tissue inhibitor of metalloprotease-3 (TIMP3) and do so through different Jak kinaes. As evidence of differential regulation of gene function by IL-4 and IL-13, we further report that MAO-A-mediated reactive oxygen species (ROS) generation is influenced by different Jak kinases. Collectively, these results have major implications for understanding the mechanism and function of alternatively activated monocytes/macrophages by IL-4 and IL-13 and add novel insights into the pathogenesis and potential treatment of different inflammatory diseases.

Objective-Although consumption of dietary supplements containing pomegranate extract by arthritis patients is on the rise, efficacy of such preparations in suppressing joint inflammation and damage is not known. The present study was designed to evaluate a standardized preparation of pomegranate extract (POMx) using collagen-induced arthritis in mice (CIA)-a widely used animal model of rheumatoid arthritis (RA).Methods-CIA susceptible DBA/1 mice were fed POMx by gavage before and after immunization with chicken type-II collagen (CII). Severity of clinical arthritis was scored using a visual scoring system. Arthritic joints were analyzed by histopathology and graded. Lysates were generated from mouse joints and the levels of anti-type-II collagen IgG and inflammatory cytokines IL-1β, IL-6 and TNF-α were quantified by ELISA. Effect of POMx on LPS-induced NO production was determined by Griess reaction and MAP kinase activation was studied by Western immunoblotting in mouse macrophages.Results-Consumption of POMx potently delayed the onset and reduced the incidence of CIA in mice. Severity of arthritis was also significantly lower in POMx -fed animals. Histopathology of the arthritic joints from POMx-fed mice demonstrated reduced joint infiltration by the inflammatory cells and the destruction of bone and cartilage were alleviated. Levels of IL-6 were significantly decreased in the joints of POMx-fed mice with CIA. In mouse macrophages, POMx abrogated multiple signal transduction pathways and downstream mediators implicated in RA pathogenesis.Conclusions-Our studies suggest that inhibition of a spectrum of signal transduction pathways and the downstream pathogenic cellular response by POMx or compounds derived from it may be a useful approach for the prevention of onset and severity of inflammatory arthritis.

Background: Mast cells and basophils are multifunctional effector cells and contain plentiful secretary granules in their cytoplasm. These cell types are involved in several inflammatory and immune events and are known to produce an array of mediators including a broad spectrum of cytokines. Pomegranate fruit is rich in anthocyanins and hydrolysable tannins; a group of polyphenolic compounds shown to be potent antioxidant with anti-inflammatory activity. However, no studies have been undertaken to investigate whether a polyphenol-rich pomegranate fruit extract (POMx) inhibits the inflammatory activity of activated human mast cells and basophils. The aim of this study was to examine whether POMx modulates inflammatory reactions using human basophilic cell line KU812.

Objective. Expression of matrix metalloproteinase 9 (MMP-9) is up-regulated in osteoarthritis (OA) and usually presents as multiple bands when synovial fluid (SF) from OA patients is analyzed by zymography. Among these bands is an ϳ125-130-kd band for high molecular weight (HMW) gelatinase, which has not been characterized. This study was undertaken to characterize the HMW MMP activity in OA SF.Methods. MMP activity in OA SF was determined by gelatin zymography. Recombinant MMPs were used to identify MMP activity on the zymogram. Western immunoblotting, immunoprecipitation, and immunodepletion analyses were performed using antibodies specific for human MMP-9 and human neutrophil gelatinase-associated lipocalin (NGAL). Human cartilage matrix degradation was determined by dimethylmethylene blue assay.Results. Zymographic analysis showed that the HMW gelatinase in OA SF comigrated with a purified NGAL-MMP-9 complex. Results of Western immunoblotting showed that the HMW gelatinase was also recognized by antibodies specific for human NGAL or human MMP-9. These same antibodies also immunoprecipitated the HMW gelatinase activity from OA SF. The NGAL-MMP-9 complex was reconstituted in vitro in gelatinase buffer. In the presence of NGAL, MMP-9 activity was stabilized; in the absence of NGAL, rapid loss of MMP-9 activity occurred. MMP-9-mediated release of cartilage matrix proteoglycans was significantly higher in the presence of NGAL (P < 0.05).Conclusion. Our findings demonstrate that the HMW gelatinase activity in OA SF represents a complex of NGAL and MMP-9. The ability of NGAL to protect MMP-9 activity is relevant to cartilage matrix degradation in OA and may represent an important mechanism by which NGAL may contribute to the loss of cartilage matrix proteins in OA.The developed world's aging population has experienced a dramatic increase in the incidence of joint dysfunction and osteoarthritis (OA), leading to a compromised quality of life. Aging, biomechanical stress, and oxidative stress, in addition to genetic factors and trauma, all appear to be associated with degenerative and progressive cartilage and bone changes in OA, particularly in the weight-bearing joints. Although OA is not considered an inflammatory disease by traditional standards, elevated levels of proinflammatory cytokines, such as interleukin-1␤ (IL-1␤) and tumor necrosis factor ␣, have been observed in OA synovial fluid (SF), supporting the notion that there is an inflammatory component associated with the pathogenesis of OA (for review, see refs. 1-3).The only cell type present in articular cartilage is the chondrocyte, which is embedded within an extracellular matrix (ECM) primarily composed of type II collagen and aggrecan. Chondrocytes arise from a mesenchymal progenitor cell and are responsible for the biosynthesis of ECM proteins and their transport into the space occupied by the ECM. Chondrocytes play an important role in cartilage homeostasis by maintaining the proper balance between anabolic pathways, which Supported in part by the NIH...

Several recent studies have documented that supplementation with pomegranate fruit extract inhibits inflammatory symptoms in vivo. However, the molecular basis of the observed effects has not been fully revealed. Although previous studies have documented the inhibition of nitric oxide and cyclooxygenase (COX) activity in vitro by plant and fruit extracts added directly into the culture medium but whether concentrations of bioactive compounds sufficient enough to exert such inhibitory effects in vivo can be achieved through oral consumption has not been reported. In the present study we determined the effect of rabbit plasma obtained after ingestion of a polyphenol rich extract of pomegranate fruit (PFE) on COX enzyme activity ex vivo and the IL-1β-induced production of NO and PGE 2 in chondrocytes in vitro. Plasma samples collected before and 2 hr after supplementation with PFE were tested. Plasma samples collected after oral ingestion of PFE were found to inhibit the IL-1β-induced PGE 2 and NO production in chondrocytes. These same plasma samples also inhibited both COX-1 and COX-2 enzyme activity ex vivo but the effect was more pronounced on the enzyme activity of COX-2 enzyme. Taken together these results provide additional evidence of the bioavailability and bioactivity of compounds present in pomegranate fruit after oral ingestion. Furthermore, these studies suggest that PFE-derived bioavailable compounds may exert an anti-inflammatory effect by inhibiting the inflammatory cytokine-induced production of PGE 2 and NO in vivo.

The latent HIV reservoir is generated following HIV infection of activated effector CD4 T cells, which then transition to a memory phenotype. Here, we describe an ex vivo method, called QUECEL (quiescent effector cell latency), that mimics this process efficiently and allows production of large numbers of latently infected CD4+ T cells. Naïve CD4+ T cells were polarized into the four major T cell subsets (Th1, Th2, Th17, and Treg) and subsequently infected with a single-round reporter virus which expressed GFP/CD8a. The infected cells were purified and coerced into quiescence using a defined cocktail of cytokines, including tumor growth factor beta, interleukin-10 (IL-10), and IL-8, producing a homogeneous population of latently infected cells. Flow cytometry and transcriptome sequencing (RNA-Seq) demonstrated that the cells maintained the correct polarization phenotypes and had withdrawn from the cell cycle. Key pathways and gene sets enriched during transition from quiescence to reactivation include E2F targets, G2M checkpoint, estrogen response late gene expression, and c-myc targets. Reactivation of HIV by latency-reversing agents (LRAs) closely mimics RNA induction profiles seen in cells from well-suppressed HIV patient samples using the envelope detection of in vitro transcription sequencing (EDITS) assay. Since homogeneous populations of latently infected cells can be recovered, the QUECEL model has an excellent signal-to-noise ratio and has been extremely consistent and reproducible in numerous experiments performed during the last 4 years. The ease, efficiency, and accuracy of the mimicking of physiological conditions make the QUECEL model a robust and reproducible tool to study the molecular mechanisms underlying HIV latency. IMPORTANCE Current primary cell models for HIV latency correlate poorly with the reactivation behavior of patient cells. We have developed a new model, called QUECEL, which generates a large and homogenous population of latently infected CD4+ memory cells. By purifying HIV-infected cells and inducing cell quiescence with a defined cocktail of cytokines, we have eliminated the largest problems with previous primary cell models of HIV latency: variable infection levels, ill-defined polarization states, and inefficient shutdown of cellular transcription. Latency reversal in the QUECEL model by a wide range of agents correlates strongly with RNA induction in patient samples. This scalable and highly reproducible model of HIV latency will permit detailed analysis of cellular mechanisms controlling HIV latency and reactivation.

Objectives: Although the prevalence and mental health consequences of childhood maltreatment among adolescents have been studied widely, there are few data addressing these issues in Asian lower middle–income countries. Here, we assessed the prevalence and types of childhood maltreatment and, for the first time, examined their association with current mental health problems in Indian adolescents with a history of child work. Methods: One hundred and thirty-two adolescents (12–18 years; 114 males, 18 females) with a history of child work were interviewed using the Child Maltreatment, Conventional Crime, and Witnessing and Indirect Victimisation modules of the Juvenile Victimization Questionnaire. Potential psychiatric diagnoses and current emotional and behavioural problems were assessed using the culturally adapted Hindi versions of the Youth’s Inventory–4R and the Strengths and Difficulties Questionnaire, respectively. Results: A large proportion of the sample reported childhood abuse or neglect (83.36%), direct or indirect victimisation (100%) and experienced symptoms of one or more psychiatric disorders (83.33%). Of the most common maltreatment types, physical abuse was present for 72.73% (extra-familial 56.25%, intra-familial 42.71%), emotional abuse for 47.7% (extra-familial 74.6%, intra-familial 12.9%), general neglect for 17.4% and unsafe home for 45.5% of the adolescents. All these maltreatment types were associated with poor mental health, with emotional abuse showing the strongest and wide-ranging impact. Conclusions: Indian adolescents with a history of child work are at an extremely high risk of extra-familial physical and emotional abuse as well as victimisation. They also experience a range of psychiatric symptoms, especially if they suffered emotional abuse. There is an urgent need for routine mental health screening and to consider emotional abuse in all current and future top-down and bottom-up approaches to address childhood maltreatment, as well as in potential interventions to ameliorate its adverse effects on mental health and well-being, of child and adolescent workers.

One strategy for a functional cure of HIV-1 is “block and lock”, which seeks to permanently suppress the rebound of quiescent HIV-1 by epigenetic silencing. For the bivalent promoter in the HIV LTR, both histone 3 lysine 27 tri-methylation (H3K27me3) and DNA methylation are associated with viral suppression, while H3K4 tri-methylation (H3K4me3) is correlated with viral expression. However, H3K27me3 is readily reversed upon activation of T-cells through the T-cell receptor. In an attempt to suppress latent HIV-1 in a stable fashion, we knocked down the expression or inhibited the activity of UTX/KDM6A, the major H3K27 demethylase, and investigated its impact on latent HIV-1 reactivation in T cells. Inhibition of UTX dramatically enhanced H3K27me3 levels at the HIV LTR and were associated with increased DNA methylation. In latently infected cells from patients, GSK-J4, which is a potent dual inhibitor of the H3K27me3/me2-demethylases JMJD3/KDM6B and UTX/KDM6A, effectively suppressed the reactivation of latent HIV-1 and also induced DNA methylation at specific sites in the 5’LTR of latent HIV-1 by the enhanced recruitment of DNMT3A to HIV-1. Nonetheless, suppression of HIV-1 through epigenetic silencing required the continued treatment with GSK-J4 and was rapidly reversed after removal of the drug. DNA methylation was also rapidly lost after removal of drug, suggesting active and rapid DNA-demethylation of the HIV LTR. Thus, induction of epigenetic silencing by histone and DNA methylation appears to be insufficient to permanently silence HIV-1 proviral transcription.