Explore the vast range of titles available.

Peroxisome proliferator-activated receptor (PPAR)γ is a global transcriptional regulator associated with anti-inflammatory actions. It is highly expressed in alveolar macrophages (AMs), which are unable to clear the intracellular pathogen Mycobacterium tuberculosis (M.tb). Although M.tb infection induces PPARγ in human macrophages, which contributes to M.tb growth, the mechanisms underlying this are largely unknown. We undertook NanoString gene expression analysis to identify novel PPARγ effectors that condition macrophages to be more susceptible to M.tb infection. This revealed several genes that are differentially regulated in response to PPARγ silencing during M.tb infection, including the Bcl-2 family members Bax (pro-apoptotic) and Mcl-1 (pro-survival). Apoptosis is an important defense mechanism that prevents the growth of intracellular microbes, including M.tb, but is limited by virulent M.tb. This suggested that M.tb differentially regulates Mcl-1 and Bax expression through PPARγ to limit apoptosis. In support of this, gene and protein expression analysis revealed that Mcl-1 expression is driven by PPARγ during M.tb infection in human macrophages. Further, 15-lipoxygenase (15-LOX) is critical for PPARγ activity and Mcl-1 expression. We also determined that PPARγ and 15-LOX regulate macrophage apoptosis during M.tb infection, and that pre-clinical therapeutics that inhibit Mcl-1 activity significantly limit M.tb intracellular growth in both human macrophages and an in vitro TB granuloma model. In conclusion, identification of the novel PPARγ effector Mcl-1 has determined PPARγ and 15-LOX are critical regulators of apoptosis during M.tb infection and new potential targets for host-directed therapy for M.tb.

Abnormally high spiking activity can damage neurons. Signaling systems to protect neurons from the consequences of abnormal discharge activity have been postulated. We generated conditional mutant mice that lack expression of the cannabinoid receptor type 1 in principal forebrain neurons but not in adjacent inhibitory intemeurons. In mutant mice, the excitotoxin kainic acid (KA) induced excessive seizures in vivo. The threshold to KA-induced neuronal excitation in vitro was severely reduced in hippocampal pyramidal neurons of mutants. KA administration rapidly raised hippocampal levels of anandamide and induced protective mechanisms in wild-type principal hippocampal neurons. These protective mechanisms could not be triggered in mutant mice. The endogenous cannabinoid system thus provides on-demand protection against acute excitotoxicity in central nervous system neurons.

Maternal and neonatal mortality rates remain high in many low-income and middle-income countries. Different approaches for the improvement of birth outcomes have been used in community-based interventions, with heterogeneous effects on survival. We assessed the effects of women's groups practising participatory learning and action, compared with usual care, on birth outcomes in low-resource settings. We did a systematic review and meta-analysis of randomised controlled trials undertaken in Bangladesh, India, Malawi, and Nepal in which the effects of women's groups practising participatory learning and action were assessed to identify population-level predictors of effect on maternal mortality, neonatal mortality, and stillbirths. We also reviewed the cost-effectiveness of the women's group intervention and estimated its potential effect at scale in Countdown countries. Seven trials (119 428 births) met the inclusion criteria. Meta-analyses of all trials showed that exposure to women's groups was associated with a 23% non-significant reduction in maternal mortality (odds ratio 0·77, 95% CI 0·48–1·23), a 20% reduction in neonatal mortality (0·80, 0·67–0·96), and a 7% non-significant reduction in stillbirths (0·93, 0·82–1·05), with high heterogeneity for maternal (I2=64·0%, p=0·011) and neonatal results (I2=73·2%, p=0·001). In the meta-regression analyses, the proportion of pregnant women in groups was linearly associated with reduction in both maternal and neonatal mortality (p=0·019 and p=0·009, respectively). A subgroup analysis of the four studies in which at least 30% of pregnant women participated in groups showed a 49% reduction in maternal mortality (0·51, 0·29–0·89) and a 33% reduction in neonatal mortality (0·67, 0·60–0·75). The intervention was cost effective by WHO standards and could save an estimated 283 000 newborn infants and 36 600 mothers per year if implemented in rural areas of 74 Countdown countries. With the participation of at least a third of pregnant women and adequate population coverage, women's groups practising participatory learning and action are a cost-effective strategy to improve maternal and neonatal survival in low-resource settings. Wellcome Trust, Ammalife, and National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care for Birmingham and the Black Country programme.

The PIWI-interacting RNA (piRNA) pathway prevents endogenous genomic parasites, i.e. transposable elements, from damaging the genetic material of animal gonadal cells. Specific regions in the genome, called piRNA clusters, are thought to define each species’ piRNA repertoire and therefore its capacity to recognize and silence specific transposon families. The unistrand cluster flamenco ( flam ) is essential in the somatic compartment of the Drosophila ovary to restrict Gypsy -family transposons from infecting the neighbouring germ cells. Disruption of flam results in transposon de-repression and sterility, yet it remains unknown whether this silencing mechanism is present more widely. Here, we systematically characterise 119 Drosophila species and identify five additional flam -like clusters separated by up to 45 million years of evolution. Small RNA-sequencing validated these as bona-fide unistrand piRNA clusters expressed in somatic cells of the ovary, where they selectively target transposons of the Gypsy family. Together, our study provides compelling evidence of a widely conserved transposon silencing mechanism that co-evolved with virus-like Gypsy -family transposons. To control transposable elements, fruit flies rely on distinct genomic regions called piRNA clusters. Here, new piRNA clusters were identified across diverse Drosophila species, displaying a conserved and specialised role in the control of endogenous retroviruses in ovarian somatic cells.

BackgroundA cluster randomised trial of mHealth and participatory learning and action (PLA) community mobilisation interventions showed that PLA significantly reduced the prevalence of intermediate hyperglycaemia and type 2 diabetes mellitus (T2DM) and the incidence of T2DM among adults in rural Bangladesh; mHealth improved knowledge but showed no effect on glycaemic outcomes. We explore the equity of intervention reach and impact.MethodsIntervention reach and primary outcomes of intermediate hyperglycaemia and T2DM were assessed through interview surveys and blood fasting glucose and 2-hour oral glucose tolerance tests among population-based samples of adults aged ≥30 years. Age-stratified, gender-stratified and wealth-stratified intervention effects were estimated using random effects logistic regression.ResultsPLA participants were similar to non-participants, though female participants were younger and more likely to be married than female non-participants. Differences including age, education, wealth and marital status were observed between individuals exposed and those not exposed to the mHealth intervention.PLA reduced the prevalence of T2DM and intermediate hyperglycaemia in all age, gender and wealth strata. Reductions in 2-year incidence of T2DM of at least 51% (0.49, 95% CI 0.26 to 0.92) were observed in all strata except among the oldest and least poor groups. mHealth impact on glycaemic outcomes was observed only among the youngest group, where a 47% reduction in the 2-year incidence of T2DM was observed (0.53, 95% CI 0.28 to 1.00).ConclusionLarge impacts of PLA across all strata indicate a highly effective and equitable intervention. mHealth may be more suitable for targeting higher risk, younger populations.Trial registration number ISRCTN41083256.

Background Diabetes is 7th largest cause of death worldwide, and prevalence is increasing rapidly in low-and middle-income countries. There is an urgent need to develop and test interventions to prevent and control diabetes and develop the theory about how such interventions can be effective. We conducted a participatory learning and action (PLA) intervention with community groups in rural Bangladesh which was evaluated through a cluster randomised controlled trial. There was a large reduction in the combined prevalence of type 2 diabetes and intermediate hyperglycaemia in the PLA group compared with the control group. We present findings from qualitative process evaluation research to explore how this intervention was effective. Methods We conducted group interviews and focus group discussions using photovoice with purposively sampled group attenders and non-attenders, and intervention implementers. Data were collected before the trial analysis. We used inductive content analysis to generate theory from the data. Results The intervention increased the health literacy of individuals and communities - developing their knowledge, capacity and self-confidence to enact healthy behaviours. Community, household and individual capacity increased through social support and social networks, which then created an enabling community context, further strengthening agency and enabling community action. This increased opportunities for healthy behaviour. Community actions addressed lack of awareness about diabetes, gendered barriers to physical activity and lack of access to blood glucose testing. The interaction between the individual, household, and community contexts amplified change, and yet there was limited engagement with macro level, or ‘state’, barriers to healthy behaviour. Conclusions The participatory approach enabled groups to analyse how context affected their ability to have healthy behaviours and participants engaged with issues as a community in the ways that they felt comfortable. We suggest measuring health literacy and social networks in future interventions and recommend specific capacity strengthening to develop public accountability mechanisms and health systems strengthening to complement community-based interventions. Trial registration Registered at ISRCTN on 30th March 2016 (Retrospectively Registered) Registration number: ISRCTN41083256 .

Glioblastoma multiforme (GBM) is a highly aggressive malignant brain tumor with fatal outcome. Tumor-associated macrophages and microglia (TAMs) have been found to be major tumor-promoting immune cells in the tumor microenvironment. Hence, modulation and reeducation of tumor-associated macrophages and microglia in GBM is considered a promising antitumor strategy. Resident microglia and invading macrophages have been shown to have distinct origin and function. Whereas yolk sac-derived microglia reside in the brain, blood-derived monocytes invade the central nervous system only under pathological conditions like tumor formation. We recently showed that disruption of the SIRPα-CD47 signaling axis is efficacious against various brain tumors including GBM primarily by inducing tumor phagocytosis. However, most effects are attributed to macrophages recruited from the periphery but the role of the brain resident microglia is unknown. Here, we sought to utilize a model to distinguish resident microglia and peripheral macrophages within the GBM-TAM pool, using orthotopically xenografted, immunodeficient, and syngeneic mouse models with genetically color-coded macrophages (Ccr2 RFP) and microglia (Cx3cr1 GFP). We show that even in the absence of phagocytizing macrophages (Ccr2 RFP/RFP), microglia are effector cells of tumor cell phagocytosis in response to anti-CD47 blockade. Additionally, macrophages and microglia show distinct morphological and transcriptional changes. Importantly, the transcriptional profile of microglia shows less of an inflammatory response which makes them a promising target for clinical applications.

Antigen presentation by major histocompatibility complex class II (MHC-II) molecules is crucial for eliciting an efficient immune response by CD4+ T cells and maintaining self-antigen tolerance. Some MHC-II alleles are known to be positively or negatively associated with the risk of the development of different autoimmune diseases (ADs), including those characterized by the emergence of autoreactive T cells. Apparently, the MHC-II presentation of self-antigens contributes to the autoimmune T cell response, initiated through a breakdown of central tolerance to self-antigens in the thymus. The appearance of autoreactive T cell might be the result of (i) the unusual interaction between T cell receptors (TCRs) and self-antigens presented on MHC-II; (ii) the posttranslational modifications (PTMs) of self-antigens; (iii) direct loading of the self-antigen to classical MHC-II without additional nonclassical MHC assistance; (iv) the proinflammatory environment effect on MHC-II expression and antigen presentation; and (v) molecular mimicry between foreign and self-antigens. The peculiarities of the processes involved in the MHC-II-mediated presentation may have crucial importance in the elucidation of the mechanisms of triggering and developing ADs as well as for clarification on the protective effect of MHC-II alleles that are negatively associated with ADs.

Acquisition and storage of aversive memories is one of the basic principles of central nervous systems throughout the animal kingdom 1 . In the absence of reinforcement, the resulting behavioural response will gradually diminish to be finally extinct. Despite the importance of extinction 2 , its cellular mechanisms are largely unknown. The cannabinoid receptor 1 (CB1) 3 and endocannabinoids 4 are present in memory-related brain areas 5 , 6 and modulate memory 7 , 8 . Here we show that the endogenous cannabinoid system has a central function in extinction of aversive memories. CB1-deficient mice showed strongly impaired short-term and long-term extinction in auditory fear-conditioning tests, with unaffected memory acquisition and consolidation. Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction. Consistently, tone presentation during extinction trials resulted in elevated levels of endocannabinoids in the basolateral amygdala complex, a region known to control extinction of aversive memories 9 . In the basolateral amygdala, endocannabinoids and CB1 were crucially involved in long-term depression of GABA (γ-aminobutyric acid)-mediated inhibitory currents. We propose that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.