The estrogen receptor α (ERα) controls cell proliferation and tumorigenesis by recruiting various cofactors to estrogen response elements (EREs) to control gene transcription. A deeper understanding of these transcriptional mechanisms may uncover therapeutic targets for ERα-dependent cancers. We show that BRD4 regulates ERα-induced gene expression by affecting elongation-associated phosphorylation of RNA polymerase II (RNAPII) and histone H2B monoubiquitination. Consistently, BRD4 activity is required for proliferation of ER(+) breast and endometrial cancer cells and uterine growth in mice. Genome-wide studies revealed an enrichment of BRD4 on transcriptional start sites of active genes and a requirement of BRD4 for H2B monoubiquitination in the transcribed region of estrogen-responsive genes. Importantly, we demonstrate that BRD4 occupancy on distal EREs enriched for H3K27ac is required for recruitment and elongation of RNAPII on EREs and the production of ERα-dependent enhancer RNAs. These results uncover BRD4 as a central regulator of ERα function and potential therapeutic target.
Proper temporal epigenetic regulation of gene expression is essential for cell fate determination and tissue development. The Bromodomain-containing Protein-4 (BRD4) was previously shown to control the transcription of defined subsets of genes in various cell systems. In this study we examined the role of BRD4 in promoting lineage-specific gene expression and show that BRD4 is essential for osteoblast differentiation. Genome-wide analyses demonstrate that BRD4 is recruited to the transcriptional start site of differentiation-induced genes. Unexpectedly, while promoter-proximal BRD4 occupancy correlated with gene expression, genes which displayed moderate expression and promoter-proximal BRD4 occupancy were most highly regulated and sensitive to BRD4 inhibition. Therefore, we examined distal BRD4 occupancy and uncovered a specific co-localization of BRD4 with the transcription factors C/EBPb, TEAD1, FOSL2 and JUND at putative osteoblast-specific enhancers. These findings reveal the intricacies of lineage specification and provide new insight into the context-dependent functions of BRD4.
The prevalence of anemia is high among children and adolescents in low- and middle-income countries because of undernutrition resulting from their poor socioeconomic status and lack of knowledge on proper nutrition. We conducted a systematic review and meta-analysis to determine the prevalence of anemia among children and adolescents aged between 6 months and 19 years in Bangladesh. Databases such as PubMed, Scopus, and Google Scholar were searched to identify the studies that reported the prevalence of anemia among children and adolescents. A total of 24 studies, including the data of 14,062 cases, were included in the systematic review and meta-analysis of the time period between 1997 and 2019. The random-effects model was used to calculate the summary estimates. The protocol was registered with PROSPERO (CRD42021246960). The pooled prevalence of anemia, iron deficiency anemia (IDA), and non-severe and severe anemia were 46.8% [95% CI: 36.0–57.6], 13.6% [95% CI: 8.0–19.2], 56.4% [95% CI: 39.6–73.1] and 0.7% [95% CI: 0.1–1.4], respectively. Prevalence of anemia exhibited the highest among the children aged ≤2 years. Briefly, 91.67% of the studies were of high quality. No significant publication bias was found; however, two outlier studies were detected. The prevalence of anemia among children and adolescents was estimated as high in Bangladesh.
Behçet’s disease (BD) is a multifactorial systemic inflammatory disease of unknown aetiology characterised by several clinical manifestations including vascular involvements (i.e., both arterial and venous thrombosis). Antiphospholipid antibodies (aPLs)—including anticardiolipin (aCL), anti-β2-glycoprotein I (β2-GPI) antibodies and lupus anticoagulant (LA) are detected in systemic autoimmune diseases which contribute to thrombosis. The aim of this systematic review and meta-analysis was to evaluate the prevalence of aPLs in patients with BD as compared to controls. A protocol was registered in PROSPERO (Registration No. CRD42018088125) and a systematic literature search was conducted through PubMed, Web of Science, Embase, Scopus and ScienceDirect databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. Quality assessment was carried out by using the modified 9-star Newcastle-Ottawa Scale (NOS). Publication bias was evaluated via visualisation of contour- enhanced and trim and fill funnel plots along with Begg's and Egger's tests. We included ten case-control studies (a total of 999 participants from 380 BD patients and 619 controls) based on the inclusion criteria. The prevalence of aCL (OR: 12.10, 95% CI: 5.15–28.41, p<0.00001) and anti-β2-GPI antibodies (OR: 23.57, 95% CI: 1.31–423.63, p = 0.03) were statistically significant, however, the prevalence of LA was not significant (OR: 13.77, 95% CI: 0.65–293.59, p = 0.09). The results remained statistically significant from different sensitivity analyses which represented the robustness of this meta-analysis. According to the NOS, 50.0% of the studies were considered as of high methodological quality (low risk of bias). No significant publication bias was detected from contour-enhanced and trim and fill funnel plots or Begg's and Egger’s tests. This meta-analysis established that there is a significantly high prevalence of aPLs (i.e., aCL and anti-β2-GPI antibodies) in patients with BD when compared to controls.
The coordinated temporal and spatial activation of gene expression is essential for proper stem cell differentiation. The Chromodomain Helicase DNA-binding protein 1 (CHD1) is a chromatin remodeler closely associated with transcription and nucleosome turnover downstream of the transcriptional start site (TSS). In this study, we show that CHD1 is required for the induction of osteoblast-specific gene expression, extracellular-matrix mineralization and ectopic bone formation in vivo. Genome-wide occupancy analyses revealed increased CHD1 occupancy around the TSS of differentiation-activated genes. Furthermore, we observed that CHD1-dependent genes are mainly induced during osteoblast differentiation and are characterized by higher levels of CHD1 occupancy around the TSS. Interestingly, CHD1 depletion resulted in increased pausing of RNA Polymerase II (RNAPII) and decreased H2A.Z occupancy close to the TSS, but not at enhancer regions. These findings reveal a novel role for CHD1 during osteoblast differentiation and provide further insights into the intricacies of epigenetic regulatory mechanisms controlling cell fate determination.