RESUMO
Background: Cis-regulatory elements (CREs) play crucial roles in regulating gene expression during erythroid cell differentiation. Genome-wide erythroid-specific CREs have not been characterized in chicken erythroid cells, which is an organism model used to study epigenetic regulation during erythropoiesis. Methods: Analysis of public genome-wide accessibility (ATAC-seq) maps, along with transcription factor (TF) motif analysis, CTCF, and RNA Pol II occupancy, as well as transcriptome analysis in fibroblasts and erythroid HD3 cells, were used to characterize erythroid-specific CREs. An α-globin CRE was identified, and its regulatory activity was validated in vitro and in vivo by luciferase activity and genome-editing assays in HD3 cells, respectively. Additionally, circular chromosome conformation capture (UMI-4C) assays were used to distinguish its role in structuring the α-globin domain in erythroid chicken cells. Results: Erythroid-specific CREs displayed occupancy by erythroid TF binding motifs, CTCF, and RNA Pol II, as well as an association with genes involved in hematopoiesis and cell differentiation. An α-globin CRE, referred to as CRE-2, was identified as exhibiting enhancer activity over αD and αA genes in vitro and in vivo. Induction of terminal erythroid differentiation showed that α-globin CRE-2 is required for the induction of αD and αA. Analysis of TF binding motifs at α-globin CRE-2 shows apparent regulation mediated by GATA-1, YY1, and CTCF binding. Conclusion: Our findings demonstrate that cell-specific CREs constitute a key mechanism that contributes to the fine-tuning gene regulation of erythroid cell differentiation and provide insights into the annotation and characterization of CREs in chicken cells.
RESUMO
BACKGROUND: While the bioavailability of cocoa polyphenols, particularly of the monomer (-)-epicatechin, has been investigated after a single-dose intake, the effect of sustained cocoa consumption on the metabolic profile of the structurally related (-)-epicatechin metabolites (SREMs) has not been investigated. METHODS: A randomized, controlled crossover clinical trial in healthy young adults (18-40 year) was conducted to evaluate SREMs after consumption of a single-dose and after daily consumption of 1.3 g of polyphenol-rich cocoa powder for 28 days. The circulating SREMs were measured by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). RESULTS: Twenty subjects (eleven males and nine females) were enrolled. The SREMs concentrations increased to 1741 ± 337 nM after a single-dose and to 1445 ± 270 nM after sustained supplementation. Sulfate conjugates showed higher levels in females (p < 0.05). The epicatechin-3'-glucuronide (E3'G) and epicatechin-3'-sulfate (E3'S) were the most abundant metabolites in all subjects. A high intra-individual correlation (r = 0.72, p < 0.001) between SREMs concentrations after single-dose and sustained supplementation was observed. The antioxidant capacity of plasma did not change in response to the intervention and was not correlated with any of the SREMs. CONCLUSION: The individual SREMs profile and concentrations after a 28-day supplementation are comparable to those after a single dose.
