Project description:HNF4a has been shown to be a central regulator of hepatocyte differentiation and function in adult mice. It was recently shown the HNF4a regulates the onset of hepatic gene expression during liver differentiation in vitro and is critical for the specification of liver towards a hepatic fate We examined the global gene expression of the differentiaiton of iPS cells into specified hepatic cells on consecutive days of liver differentiation (Mallanna et al 2013) to determine the onset of hepatic gene expression and the role HNF4a plays during hepatic specification.
Project description:The winged helix transcription factor Foxl1 is a marker for progenitor cells and their descendants in the mouse liver in vivo. Here, we purify progenitor cells from Foxl1-Cre; RosaYFP mice and evaluate their proliferative and differentiation potential in vitro. Treatment of Foxl1-Cre; RosaYFP mice with 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet led to an increase of the percentage of YFP-labeled Foxl1+ cells. Clonogenic assays demonstrated that up to 3.6% of Foxl1+ cells had proliferative potential. Foxl1+ cells differentiated into cholangiocytes and into hepatocytes in vitro, depending on the culture condition employed. Microarray analyses indicated that Foxl1+ cells express stem cell markers such as Prom1 as well as differentiation markers such as Ck19 and Hnf4a. Thus, the Foxl1-Cre; RosaYFP model allows for easy isolation of adult hepatic progenitor cells that can be expanded and differentiated in culture. Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE28890: Foxl1-Cre-marked Adult Hepatic Progenitors Have Clonogenic and Bi-Lineage Differentiation Potential - Time Course GSE28891: Foxl1-Cre-marked Adult Hepatic Progenitors Have Clonogenic and Bi-Lineage Differentiation Potential - Differentiated vs Primary
Project description:We observed gene expression changes in livers of cold exposed mice along with changes in global genome occupancy for the transcription factor HNF4a, RNA polymerase II and the histone marker H3K27Ac, suggesting a hepatic transcriptional response to cold xposure.
Project description:Generating insulin-producing β-cells from human induced pluripotent stem cells is a promising cell replacement therapy aimed at improving or curing certain forms of diabetes. Nevertheless, despite important recent advances, the efficient production of functionally mature β-cells is yet to be achieved, with most current differentiation protocols generating a heterogeneous population comprising of subpopulation of cells expressing different islet hormones, including hybrid polyhormonal entities. A solution to this issue is transplanting end-stages differentiating cells into living hosts, which was demonstrated to majorly improve β-cell maturation. Yet, to date, the cellular and molecular mechanisms underlying the transplanted cells response to the in vivo environment exposure was not yet properly characterized. Here we use global proteomics and large-scale imaging techniques aimed at demultiplexing and filtering cellular processes and molecular signatures modulated by the immediate in vivo effect. We show that in vivo exposure swiftly confines in vitro generated human pancreatic progenitors to single hormone expression. The global proteome landscape of the transplanted cells was closer to the one presented by native human islets, especially in regard to energy metabolism and redox balance. Moreover our study indicates a possible link between these processed and certain epigenetic regulators involved in maintenance and propagation of the islet cells identity. Pathway analysis predicted HNF1A and HNF4A as key regulators controlling the in vivo islet-promoting response, with experimental evidence confirming their involvement in confining islet cell identity. To our knowledge this is the first study demultiplexing the immediate response of the transplanted pancreatic progenitors to in vivo exposure.
Project description:The nuclear receptor HNF4A regulates embryonic and post-natal hepatocyte gene expression. Using hepatocyte-specific inactivation in mice, we show that the TAF4 subunit of TFIID acts as a cofactor for HNF4A in vivo and that HNF4A interacts directly with the TAF4-TAF12 heterodimer in vitro. In vivo, TAF4 is required to maintain HNF4A-directed embryonic gene expression at post-natal stages and for HNF4A-directed activation of post-natal gene expression. TAF4 promotes HNF4A occupancy of functional cis-regulatory elements located adjacent to the transcription start sites of post-natal expressed genes and for pre-initiation complex formation required for their expression. Promoter-proximal HNF4A-TFIID interactions are therefore required for pre-initiation complex formation and stable HNF4A occupancy of regulatory elements as two concomitant mutually dependent processes. Examination of PIC, H3k4me3, Ctcf and Hnf4a occupancy in wild-type and Taf4-/- livers by deep sequencing
Project description:The nuclear receptor HNF4A regulates embryonic and post-natal hepatocyte gene expression. Using hepatocyte-specific inactivation in mice, we show that the TAF4 subunit of TFIID acts as a cofactor for HNF4A in vivo and that HNF4A interacts directly with the TAF4-TAF12 heterodimer in vitro. In vivo, TAF4 is required to maintain HNF4A-directed embryonic gene expression at post-natal stages and for HNF4A-directed activation of post-natal gene expression. TAF4 promotes HNF4A occupancy of functional cis-regulatory elements located adjacent to the transcription start sites of post-natal expressed genes and for pre-initiation complex formation required for their expression. Promoter-proximal HNF4A-TFIID interactions are therefore required for pre-initiation complex formation and stable HNF4A occupancy of regulatory elements as two concomitant mutually dependent processes. RNA profiles in wild-type and Taf4-/- livers by deep sequencing
Project description:To determine the downstream regulatory network of HNF4A and HNF1A, two transcription factors that play important roles in the pancreas and liver and that are associated with diabetes, we generated a comprehensive genome-wide map of the binding targets of HNF4A and HNF1A in hiPSC-derived pancreatic and hepatic cells and relevant cell lines using ChIP-Seq and molecular validation. We report binding targets of HNF4A and HNF1A that map to both known and novel gene promoters, that are common or differentially bound across different cell types and developmental stages. Overall, the detailed characterisation of the regulatory roles of HNF4A and HNF1A in pancreatic beta cells and hepatic cells will potentially shed light on how dysregulation of these factors can contribute to altered tissue development and function, and thus pathogenesis of both monogenic diabetes and T2D.