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:We performed bulk RNA-seq and compared complehensive gene expression profiles of kidney organoids induced from wild type, HNF4A-KO, HNF4G-KO, and HNF4A/4G-DKO iPS cell lines.
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.
Project description:Hnf4a is specifically expressed in developing proximal tubule cells in the newborn mouse kidney. In order to identify direct target genes of Hnf4a in the developing proximal tubules, we performed ChIP-Seq of Hnf4a in the mouse kidneys at P0.
Project description:The availability of pluripotent stem cells offers the possibility of using such cells to model hepatic disease and development. With this in mind, we previously established a protocol that facilitates the differentiation of both human embryonic stem cells and induced pluripotent stem cells into cells that share many characteristics with hepatocytes. The use of highly defined culture conditions and the avoidance of feeder cells or embryoid bodies allowed synchronous and reproducible differentiation to occur. The differentiation towards a hepatocyte-like fate appeared to recapitulate many of the developmental stages normally associated with the formation of hepatocytes in vivo. In the current study, we addressed the feasibility of using human pluripotent stem cells to probe the molecular mechanisms underlying human hepatocyte differentiation. We demonstrate (1) that human embryonic stem cells express a number of mRNAs that characterize each stage in the differentiation process, (2) that gene expression can be efficiently depleted throughout the differentiation time course using shRNAs expressed from lentiviruses and (3) that the nuclear hormone receptor HNF4A is essential for specification of human hepatic progenitor cells by establishing the expression of the network of transcription factors that controls the onset of hepatocyte cell fate.
Project description:Specific regulation of target genes by transforming growth factor-β (TGF-β) in a given cellular context is determined in part by transcription factors and cofactors that interact with the Smad complex. In the present study, we determined Smad2 and Smad3 (Smad2/3) binding regions in the promoters of known genes in HepG2 hepatoblastoma cells, and compared them to those in HaCaT epidermal keratinocytes to elucidate the mechanisms of cell type- and context-dependent regulation of transcription induced by TGF-β. Our results show that 81% of the Smad2/3 binding regions in HepG2 cells were not shared with those found in HaCaT cells. Hepatocyte nuclear factor 4α (HNF4α) is expressed in HepG2 cells, but not in HaCaT cells, and the HNF4α binding motif was identified as an enriched motif in the HepG2-specific Smad2/3 binding regions. ChIP-sequencing analysis of HNF4A binding regions under TGF-β stimulation revealed that 32.5% of the Smad2/3 binding regions overlapped HNF4A bindings. MIXL1 was identified as a new combinatorial target of HNF4A and Smad2/3, and both the HNF4A protein and its binding motif were required for the induction of MIXL1 by TGF-β in HepG2 cells. These findings generalize the importance of binding of HNF4A on Smad2/3 binding genomic regions for HepG2-specific regulation of transcription by TGF-β, and suggest that certain transcription factors expressed in a cell-type-specific manner play important roles in the transcription regulated by the TGF-β-Smad signaling pathway. HepG2 cells were treated with TGF-beta for 1.5 h or left untreated. anti-HNF4A ChIP-seq was performed. One lane was used for each sample.
Project description:Specific regulation of target genes by transforming growth factor-β (TGF-β) in a given cellular context is determined in part by transcription factors and cofactors that interact with the Smad complex. In the present study, we determined Smad2 and Smad3 (Smad2/3) binding regions in the promoters of known genes in HepG2 hepatoblastoma cells, and compared them to those in HaCaT epidermal keratinocytes to elucidate the mechanisms of cell type- and context-dependent regulation of transcription induced by TGF-β. Our results show that 81% of the Smad2/3 binding regions in HepG2 cells were not shared with those found in HaCaT cells. Hepatocyte nuclear factor 4α (HNF4α) is expressed in HepG2 cells, but not in HaCaT cells, and the HNF4α binding motif was identified as an enriched motif in the HepG2-specific Smad2/3 binding regions. ChIP-sequencing analysis of HNF4A binding regions under TGF-β stimulation revealed that 32.5% of the Smad2/3 binding regions overlapped HNF4A bindings. MIXL1 was identified as a new combinatorial target of HNF4A and Smad2/3, and both the HNF4A protein and its binding motif were required for the induction of MIXL1 by TGF-β in HepG2 cells. These findings generalize the importance of binding of HNF4A on Smad2/3 binding genomic regions for HepG2-specific regulation of transcription by TGF-β, and suggest that certain transcription factors expressed in a cell-type-specific manner play important roles in the transcription regulated by the TGF-β-Smad signaling pathway.