Transcriptional coactivator MED15 is required for beta cell maturation
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ABSTRACT:
PROVIDER: PRJNA564631 | ENA |
REPOSITORIES: ENA
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Project description:Mediator, a co-regulator required for RNA pol II activity, interacts with tissue-specific transcription factors to regulate development and maintain homeostasis. We sought to understand whether Mediator subunit MED15 acts as a node that controls tissue-specific gene expression, using pancreatic insulin-producing β-cell maturation as a model. We found Med15 to be expressed during mouse pancreatic organogenesis and β-cell maturation; moreover, islets from human T2D donors feature reduced MED15 expression. Loss of Med15 in mouse β-cells caused defects in maturation without affecting β-cell mass or insulin expression. ChIP-seq and co-immunoprecipitation analyses determined that Med15 binds β-cell transcription factors Nkx6-1 and NeuroD1 to regulate key β-cell maturation genes. Human embryonic stem cell derived β-like cells, genetically engineered to express high levels of MED15, had increased maturation markers and improved insulin secretion. We provide the first evidence of the importance of Mediator in β-cell maturation and demonstrate an additional layer of control that tunes transcription factor function.
2024-09-10 | GSE137145 | GEO
Project description:Islet β-cells from newborn mammals need a maturation process to become mature functional beta cells. The detailed molecular mechanisms were not completely understood. This study was designed to reveal the dynamic gene expression changes during pancreatic beta-cell maturation in postnatal mice. We also want to understand how genetic mutations that impair beta-cell function change the genetic networks involved in the beta-cell maturation process. For these aims, pancreatic beta cells were isolated at P1 islets based on the expression of a MipeGFP transgene in a genetic background with pancreatic specific inactivation of Myt1, Myt1L, and St18 (denoted as MytDelpanc; MipeGFP).
2018-04-01 | E-MTAB-6615 | biostudies-arrayexpress
Project description:The weaning period consist of a critical postnatal window for structural and physiologic maturation of rat beta cells. To investigate transcriptome changes involved in the maturation of beta cells neighboring this period we performed microarray analysis in FACS beta cell enriched populations to detail the global programme of gene expression to identify its changes during this process. Male Wistar rats were selected at the initial point of a postnatal critical period (postnatal 20d) for pancreatic maturation for RNA extraction and hybridization on Affymetrix microarrays. We obtained immature and mature beta cell-enriched populations from postnatal 20d and 2 months animals in order to compare their expression profiles. To that end, we used primary cultured FACS-enriched beta cell populations according to their FSC, SSC and autoflourescence. We used three replicates for each condition.
2016-07-27 | E-GEOD-76969 | biostudies-arrayexpress
Project description:Activation domains (ADs) within transcription factors (TFs) induce gene expression by recruiting coactivators to specific regulatory regions. Within the prevailing model, TF-coactivator recruitment is independent of DNA binding, which is consistent with direct AD-coactivator interactions seen outside cells. However, this independence was not yet tested within the genomic context. Here, we targeted two Med15-interacting ADs to hundreds of budding yeast promoters through fusions with multiple DNA binding domains (DBDs), gradually controlling their abundances using libraries of synthetic promoters. Genomic profiling revealed that AD identity influences DNA binding locations and that transcription induction and Med15 recruitment are restricted to a subset of DBD-bound promoters displaying flexible expression, multiple-TFs binding, and fuzzy nucleosome architecture. Further, when fused to a DBD, Med15 redirected binding towards promoters of fuzzy nucleosomes, overcoming DBD-based preferences. Our results demonstrate that ADs and their recruited coactivators posses an inherent preference for genomic localization and, therefore, define the subset of induced promoters.
2024-07-27 | GSE234432 | GEO
Project description:Activation domains (ADs) within transcription factors (TFs) induce gene expression by recruiting coactivators to specific regulatory regions. Within the prevailing model, TF-coactivator recruitment is independent of DNA binding, which is consistent with direct AD-coactivator interactions seen outside cells. However, this independence was not yet tested within the genomic context. Here, we targeted two Med15-interacting ADs to hundreds of budding yeast promoters through fusions with multiple DNA binding domains (DBDs), gradually controlling their abundances using libraries of synthetic promoters. Genomic profiling revealed that AD identity influences DNA binding locations and that transcription induction and Med15 recruitment are restricted to a subset of DBD-bound promoters displaying flexible expression, multiple-TFs binding, and fuzzy nucleosome architecture. Further, when fused to a DBD, Med15 redirected binding towards promoters of fuzzy nucleosomes, overcoming DBD-based preferences. Our results demonstrate that ADs and their recruited coactivators posses an inherent preference for genomic localization and, therefore, define the subset of induced promoters.
2023-12-19 | GSE234431 | GEO
Project description:SC-beta Cell in vivo Maturation
| PRJNA560712 | ENA
Project description:We found that in rodents, postnatal beta-cell maturation is associated with changes in the expression of several islet microRNAs and discovered that these modifications are driven by changes in the nutrient supply. Mimicking the microRNA changes observed during β-cell maturation in newborn rat islet cells was sufficient to promote glucose-induced insulin release and to achieve a mature β-cell secretory phenotype. Moreover, the modifications in the level of some of these microRNAs reduced the proliferation of newborn β-cells, suggesting that they contribute to the limited proliferative capacity of adult β-cells. These findings demonstrated that miRNAs contribute to postnatal beta-cell maturation and development. Their role is likely to promote beta-cell adaptation to fuel supply and to maintain glucose homeostasis by regulating insulin release and proliferation. Islets from 10-day-old rats (P10) (n=4) or 3-month-old male rat (n=4) were taken. Total RNA was extracted and microRNA profiling was performed with miRNA Agilent arrays.
2014-09-04 | E-GEOD-61090 | biostudies-arrayexpress
Project description:Stem cell-derived β (SC-β) cells are an emerging regenerative therapy to compensate for loss of functional β cell mass in diabetes. Glucose-stimulated insulin secretion in SC-β cells is variable in vitro but stabilizes after transplantation and maturation under the kidney capsule of mice. We identified mechanisms correlated with functional maturation using RNA-sequencing and co-expression network analysis. In vivo maturation enhanced glucose-stimulated but not basal insulin secretion, up-regulated β cell hormones IAPP and ADCYAP1, increased expression of maturation markers MAFA, UCN3, and SIX2, and resolved endocrine identity of incompletely specified polyhormonal cells produced during differentiation. Transplantation promoted calcium signalling, induced exocytotic machinery supporting hormone secretion and improved stimulus-secretion coupling that fine-tunes insulin secretion. Growth hormone signalling emerged as candidate driver of in vivo maturation and was confirmed in vitro. Also, a large co-expression module correlated with HbA1c and was enriched in genes up-regulated during in vivo maturation but down-regulated in hyperglycaemic and palmitate stress conditions, suggesting that transcriptional maturation of SC-β cells in vivo mirrors processes lost in diabetic β cells.
2019-08-19 | GSE135944 | GEO
Project description:The weaning period consist of a critical postnatal window for structural and physiologic maturation of rat beta cells. To investigate transcriptome changes involved in the maturation of beta cells neighboring this period we performed microarray analysis in FACS beta cell enriched populations to detail the global programme of gene expression to identify its changes during this process.
2016-07-27 | GSE76969 | GEO
Project description:We found that in rodents, postnatal beta-cell maturation is associated with changes in the expression of several islet microRNAs and discovered that these modifications are driven by changes in the nutrient supply. Mimicking the microRNA changes observed during β-cell maturation in newborn rat islet cells was sufficient to promote glucose-induced insulin release and to achieve a mature β-cell secretory phenotype. Moreover, the modifications in the level of some of these microRNAs reduced the proliferation of newborn β-cells, suggesting that they contribute to the limited proliferative capacity of adult β-cells. These findings demonstrated that miRNAs contribute to postnatal beta-cell maturation and development. Their role is likely to promote beta-cell adaptation to fuel supply and to maintain glucose homeostasis by regulating insulin release and proliferation.
2014-09-04 | GSE61090 | GEO