Project description:RNAseq of osteocyte and osteoblasts enriched bone fraction from the tibiae of 6 week-old male mice with a conditional deletion of Hnf4a in osteoblasts and and WT littermates.
Project description:Intermittent fasting (IF) increases lifespan, decreases metabolic disease phenotypes, and cancer risk in model organisms, but the mechanisms mediating these effects are not fully characterized. In particular, the altered transcriptional programming has yet to be defined in key fasting responsive tissues such as liver from animals undergoing intermittent fasting. In this study, we employed every-other-day-fasting (EODF) in mice and high-resolution proteome analysis of liver and blood plasma as a screening tool to identify key regulated pathways with comparison to ad libitum fed animals. We observed many changes in the liver proteome abundance profile that were distinct from those observed after a single bout of fasting. Key among these were the induction by EODF of de novo lipogenesis (DNL) and cholesterol biosynthesis pathway enzymes, which were mirrored by related metabolite changes such as increased triacylglycerides and HMG-CoA in EODF liver of fed mice. Paradoxically, we also observed the up-regulation of mitochondrial proteins associated with fatty-acid beta oxidation including ACOT2, which is known to accelerate this pathway in vivo. The most surprising observation was the EODF-mediated 16-fold down-regulation of alpha-1-antitrypsin (SERPINA1E) in liver, which is an abundant plasma protein made exclusively in this tissue. Plasma proteome analysis confirmed a 3-fold decrease in SERPINA1E after 2 weeks of EODF among other significant changes such as increased levels of APOA4, a finding in common with previous human EODF intervention studies. We determined that in liver the SREBP1c and HNF4A transcription factors were playing a major role in the up-regulation of lipid/cholesterol synthesis and down-regulation of AAT, respectively. Further characterization of HNF4A function suggested a global inhibition of its ability to bind promoters of target genes in livers from EODF animals, which we hypothesize is mediated by either increased linoleic acid binding, or post translational modifications of HNF4A protein in EODF animal liver tissue. Together these data provide a comprehensive Omics resource highlighting the key changes observed during the intermittent fasting response in a model animal.
Project description:We profiled the genome-wide occupancy of three tissue-specific transcription factors, HNF4A, CEBPA and FOXA1, as well as the genome-wide occurrence of the histone mark, H3K4me3 in the livers of two inbred parental mouse strains (C57BL/6J and CAST/EiJ) and their F1 crosses. We also included H3K27ac data generated from F1 hybrids as well as the profiling of HNF4A, CEBPA and FOXA1 in both CEBPA and HNF4a heterozygous knock-outs.
Project description:The transcriptional regulation of drug-metabolizing enzymes and transporters (here collectively referred to as DMEs) in the developing proximal tubule is not well understood. As in the liver, DME regulation in the PT may be mediated through nuclear receptors which are thought to “sense” deviations from homeostasis by being activated by ligands, some of which are handled by DMEs, including drug transporters. Systems analysis of transcriptomic data during kidney development predicted a set of upstream transcription factors, including Hnf4a and Hnf1a, as well as Nr3c1 (Gr), Nfe2l2 (Nrf2), Ppara, and Tp53. Motif analysis of cis-regulatory further suggested that Hnf4a and Hnf1a are the main transcriptional regulators in the PT. Available expression data from tissue-specific Hnf4a KO tissues revealed that distinct subsets of DMEs were regulated by Hnf4a in a tissue-specific manner. ChIP-seq was performed to characterize the PT-specific binding sites of Hnf4a in rat kidneys at three developmental stages (prenatal, immature, adult), which further supported a major role for Hnf4a in regulating PT gene expression, including DMEs. In ex vivo kidney organ culture, an antagonist of Hnf4a (but not a similar inactive compound) led to predicted changes in DME expression, including among others Fmo1, Cyp2d2, Cyp2d4, Nqo2, as well as organic cation transporters and organic anion transporters Slc22a1(Oct1), Slc22a2 (Oct2), Slc22a6 (Oat1), Slc22a8(Oat3), and Slc47a1(Mate1). Conversely, overexpression of Hnf1a and Hnf4a in primary mouse embryonic fibroblasts (MEFs), sometimes considered a surrogate for mesenchymal stem cells, induced expression of several of these proximal tubule DMEs, as well as epithelial markers and a PT-specific brush border marker Ggt1. These cells had organic anion transporter function. Taken together, the data strongly supports a critical role for HNF4a and Hnf1a in the tissue-specific regulation of drug handling and differentiation toward a PT cellular identity. Hnf4a binding was examined in rat kidneys at three timepoints (E20, P13 and Adult) and p300 binding was examined in adult rat kidney cortex tissue using ChIP-seq. Four corresponding input DNA samples were used as controls for peak calling.
Project description:To understand how HNF4A loss affects gene expression in mouse liver. We used control and HNF4A KO mouse livers for RNA sequencing. In addition, we also examined the effect of HNF4A gain in mouse fibroblast cells by ectropically expressing HNF4A in NIH3T3 cell to identify genes that are regulated by HNF4A.
Project description:Pancreatic ductal adenocarcinoma is aggressive disease with a dismal five-year survival of 5%. Gene expression profiling has been instrumental for subtype classification in cancer, highlighting fundamental differences in tumors at the molecular level. Over the last years, multiple genomics studies have led to the classification of PDAC into two major subtypes: classical and basal-type. The classical subtype expresses higher levels of endodermal lineage specifiers, including HNF4A, GATA6, FOXA2, FOXA3 than the basal-type. The basal-type confers a worse prognosis, raising the possibility that loss of these lineage specifiers might enhance the malignant potential of PDAC. We found that the lineage specifier HNF4a plays a key role in maintaining a transcriptional network that characterizes the classical subtype, restraining growth in different PDAC models. Additionally, we demonstrated that HNF4a controls PDAC cell identity and proliferation, and represses the expression of SIX family members, two mesodermal lineage specifiers highly expressed in basal-type.