RESUMO
Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which mediates the effects of a variety of environmental stimuli in multiple tissues. Recent advances in AHR biology have underlined its importance in cells with high developmental potency, including pluripotent stem cells. Nonetheless, there is little data on AHR expression and its role during the initial stages of stem cell differentiation. The purpose of this study was to investigate the temporal pattern of AHR expression during directed differentiation of human embryonic stem cells (hESC) into neural progenitor, early mesoderm and definitive endoderm cells. Additionally, we investigated the effect of the AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the gene expression profile in hESCs and differentiated cells by RNA-seq, accompanied by identification of AHR binding sites by ChIP-seq and epigenetic landscape analysis by ATAC-seq. We showed that AHR is differentially regulated in distinct lineages. We provided evidence that TCDD alters gene expression patterns in hESCs and during early differentiation. Additionally, we identified novel potential AHR target genes, which expand our understanding on the role of this protein in different cell types.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Células-Tronco Embrionárias Humanas/citologia , Dibenzodioxinas Policloradas/toxicidade , Receptores de Hidrocarboneto Arílico/metabolismo , Biomarcadores , Diferenciação Celular/genética , Linhagem Celular , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/genética , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Corpos Embrioides/citologia , Corpos Embrioides/efeitos dos fármacos , Genoma Humano , Células-Tronco Embrionárias Humanas/efeitos dos fármacos , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , LigantesRESUMO
The aryl hydrocarbon receptor (Ahr) is a ligand-activated transcription factor primarily known for its toxicological functions. Recent studies have established its importance in many physiological processes including female reproduction, although there is limited data about the precise mechanisms how Ahr itself is regulated during ovarian follicle maturation. This study describes the expression of Ahr in ovarian granulosa cells (GCs) of immature mice in a gonadotropin-dependent manner. We show that Ahr upregulation in vivo requires both follicle stimulating hormone (FSH) and luteinizing hormone (LH) activities. FSH alone increased Ahr mRNA, but had no effect on Ahr protein level, implicating a possible LH-dependent post-transcriptional regulation. Also, the increase in Ahr protein is specific to large antral follicles in induced follicle maturation. We show that Ahr expression in GCs of mid-phase follicular maturation is downregulated by protein kinase A (PKA) signaling and activation of Ahr promoter is regulated by chromatin remodeling.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Epigênese Genética , Hormônio Foliculoestimulante/metabolismo , Regulação da Expressão Gênica , Células da Granulosa/metabolismo , Hormônio Luteinizante/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Transdução de Sinais , Animais , Biomarcadores , Cromatina/genética , Cromatina/metabolismo , Feminino , Camundongos , Folículo Ovariano/metabolismo , Receptores de Hidrocarboneto Arílico/genética , Transcrição GênicaRESUMO
Recent advances in establishing the role of the aryl hydrocarbon receptor (Ahr) in normophysiology have discovered its fundamental role, amongst others, in female reproduction. Considering previous studies suggesting the hormonal modulation of Ahr, we aimed to investigate whether in murine granulosa cells (GCs) the gonadotropins regulate Ahr expression and how this is mechanistically implemented. We found that the FSH-like substance--pregnant mare serum gonadotropin--led to stimulation of Ahr expression. More importantly hCG produced relatively rapid reduction of Ahr mRNA in GCs of preovulatory follicles. We show for the first time that LHCGR signaling in regulating the Ahr message involves protein kinase A pathway and is attributable to decreased transcription rate. Finally, we found that Ahr promoter accessibility was decreased by hCG, implicating chromatin remodeling in Ahr gene regulation by LH.