Project description:This experiment used RNA-Seq technology to explore gene expression in mouse Insm1^GFP/Pdx1^CFP HIGH [het/het] FACS sorted pancreatic cells (pre-beta cells) and Insm1^GFP/Pdx1^CFP LOW [het/het] cells (other endocrine progenitors) at E15.5 and E18.5. Comparison of Insm1 +/Pdx HIGH and Insm1 +/Pdx LOW cells revealed a set of differentially expressed genes that are required for beta cell specification.
Project description:The Insm1 gene encodes a zinc finger factor expressed in many endocrine organs. We show here that Insm1 is required for differentiation of all endocrine cell types in the pituitary. Thus, in Insm1 mutant mice, hormones characteristic of the different pituitary cell types (thyroid, follicle and melanocyte stimulating hormone, adrenocorticotrope hormone, growth hormone and prolactin) are absent or produced at markedly reduced levels. The differentiation deficit is accompanied by an up-regulated expression of components of the Notch signaling pathway. Further, skeletal muscle-specific genes are ectopically expressed, indicating that Insm1 blocks a muscle-specific expression program. Since Insm1 is also essential for differentiation of endocrine cells in the pancreas, intestine and adrenal gland, it is emerging as a transcription factor that acts in a pan-endocrine manner. The Insm1 factor contains a SNAG domain at its N-terminus, and we show here that the SNAG domain recruits histone modifying factors (Kdm1a, Hdac1/2 and Rcor1-3) and other proteins implicated in transcriptional regulation (Hmg20a/b and Gse1). Deletion of the SNAG domain in mice disrupted differentiation of pituitary endocrine cells, and resulted in an upregulated expression of components of the Notch signaling pathway and ectopic expression of skeletal muscle-specific genes. Our work demonstrates that Insm1 acts in the transcriptional network that controls differentiation of endocrine cells in the anterior pituitary gland, and requires the SNAG domain to exert this function in vivo. Analysis of genes regulated by Insm1 in embryonic day 17.5 pituitary gland. Total RNA from pituitary glands of E17.5 control embryos was compared to E17.5 Insm1 mutant embryos.
Project description:The Insm1 gene encodes a zinc finger factor expressed in many endocrine organs. We show here that Insm1 is required for differentiation of all endocrine cell types in the pituitary. Thus, in Insm1 mutant mice, hormones characteristic of the different pituitary cell types (thyroid, follicle and melanocyte stimulating hormone, adrenocorticotrope hormone, growth hormone and prolactin) are absent or produced at markedly reduced levels. The differentiation deficit is accompanied by an up-regulated expression of components of the Notch signaling pathway. Further, skeletal muscle-specific genes are ectopically expressed, indicating that Insm1 blocks a muscle-specific expression program. Since Insm1 is also essential for differentiation of endocrine cells in the pancreas, intestine and adrenal gland, it is emerging as a transcription factor that acts in a pan-endocrine manner. The Insm1 factor contains a SNAG domain at its N-terminus, and we show here that the SNAG domain recruits histone modifying factors (Kdm1a, Hdac1/2 and Rcor1-3) and other proteins implicated in transcriptional regulation (Hmg20a/b and Gse1). Deletion of the SNAG domain in mice disrupted differentiation of pituitary endocrine cells, and resulted in an upregulated expression of components of the Notch signaling pathway and ectopic expression of skeletal muscle-specific genes. Our work demonstrates that Insm1 acts in the transcriptional network that controls differentiation of endocrine cells in the anterior pituitary gland, and requires the SNAG domain to exert this function in vivo.
Project description:MicroRNAs (miRNAs) are small non-coding RNA molecules that have the ability to drive cell lineage decisions by regulating the expression of hundreds of genes. Although evidence indicates that miRNAs have roles in pancreas development and endocrine cell function, the role of miRNAs in pancreatic endocrine cell differentiation has not been systematically explored. To address this, we performed genome-wide small RNA sequencing analysis in pancreatic progenitor cells differentiated in vitro from human embryonic stem cells and endocrine cells isolated from whole human islets. This analysis revealed miRNAs that increase in expression during endocrine cell differentiation. Employing gain-of-function experiments, we identified four miRNAs that can repress a large number of genes that are normally down-regulated during endocrine cell differentiation, including genes encoding transcription factors known to regulate endocrine cell development as well as cell cycle regulators. This knowledge about miRNA target genes in conjunction with HITS-CLIP data allowed us to construct an integrated miRNA-gene regulatory network of endocrine cell differentiation. Our integrated analysis indicates a key role for the identified miRNAs in establishing a transcriptional landscape that promotes the differentiation of pancreatic progenitor cells into endocrine cells. This study not only sheds light on the mechanisms that underlie human endocrine cell differentiation, but also has important implications for devising improved protocols for producing replacement beta cells for diabetes cell therapy.
Project description:MicroRNAs (miRNAs) are small non-coding RNA molecules that have the ability to drive cell lineage decisions by regulating the expression of hundreds of genes. Although evidence indicates that miRNAs have roles in pancreas development and endocrine cell function, the role of miRNAs in pancreatic endocrine cell differentiation has not been systematically explored. To address this, we performed genome-wide small RNA sequencing analysis in pancreatic progenitor cells differentiated in vitro from human embryonic stem cells and endocrine cells isolated from whole human islets. This analysis revealed miRNAs that increase in expression during endocrine cell differentiation. Employing gain-of-function experiments, we identified four miRNAs that can repress a large number of genes that are normally down-regulated during endocrine cell differentiation, including genes encoding transcription factors known to regulate endocrine cell development as well as cell cycle regulators. This knowledge about miRNA target genes in conjunction with HITS-CLIP data allowed us to construct an integrated miRNA-gene regulatory network of endocrine cell differentiation. Our integrated analysis indicates a key role for the identified miRNAs in establishing a transcriptional landscape that promotes the differentiation of pancreatic progenitor cells into endocrine cells. This study not only sheds light on the mechanisms that underlie human endocrine cell differentiation, but also has important implications for devising improved protocols for producing replacement beta cells for diabetes cell therapy.
Project description:MicroRNAs (miRNAs) are small non-coding RNA molecules that have the ability to drive cell lineage decisions by regulating the expression of hundreds of genes. Although evidence indicates that miRNAs have roles in pancreas development and endocrine cell function, the role of miRNAs in pancreatic endocrine cell differentiation has not been systematically explored. To address this, we performed genome-wide small RNA sequencing analysis in pancreatic progenitor cells differentiated in vitro from human embryonic stem cells and endocrine cells isolated from whole human islets. This analysis revealed miRNAs that increase in expression during endocrine cell differentiation. Employing gain-of-function experiments, we identified four miRNAs that can repress a large number of genes that are normally down-regulated during endocrine cell differentiation, including genes encoding transcription factors known to regulate endocrine cell development as well as cell cycle regulators. This knowledge about miRNA target genes in conjunction with HITS-CLIP data allowed us to construct an integrated miRNA-gene regulatory network of endocrine cell differentiation. Our integrated analysis indicates a key role for the identified miRNAs in establishing a transcriptional landscape that promotes the differentiation of pancreatic progenitor cells into endocrine cells. This study not only sheds light on the mechanisms that underlie human endocrine cell differentiation, but also has important implications for devising improved protocols for producing replacement beta cells for diabetes cell therapy.
Project description:MicroRNAs (miRNAs) are small non-coding RNA molecules that have the ability to drive cell lineage decisions by regulating the expression of hundreds of genes. Although evidence indicates that miRNAs have roles in pancreas development and endocrine cell function, the role of miRNAs in pancreatic endocrine cell differentiation has not been systematically explored. To address this, we performed genome-wide small RNA sequencing analysis in pancreatic progenitor cells differentiated in vitro from human embryonic stem cells and endocrine cells isolated from whole human islets. This analysis revealed miRNAs that increase in expression during endocrine cell differentiation. Employing gain-of-function experiments, we identified four miRNAs that can repress a large number of genes that are normally down-regulated during endocrine cell differentiation, including genes encoding transcription factors known to regulate endocrine cell development as well as cell cycle regulators. This knowledge about miRNA target genes in conjunction with HITS-CLIP data allowed us to construct an integrated miRNA-gene regulatory network of endocrine cell differentiation. Our integrated analysis indicates a key role for the identified miRNAs in establishing a transcriptional landscape that promotes the differentiation of pancreatic progenitor cells into endocrine cells. This study not only sheds light on the mechanisms that underlie human endocrine cell differentiation, but also has important implications for devising improved protocols for producing replacement beta cells for diabetes cell therapy.