ABSTRACT: Mouse FGF15 and human FGF19 are orthologous proteins that regulate bile acid metabolism. However, other hepatic functions of FGF15/19 are not well characterized. We used microarrays to analyze global hepatic gene expression in mice administered FGF15 or FGF19. Total liver RNA was isolated from wild-type mice administered vehicle, purified FGF15 or recombinant FGF19 for 6 hr via a jugular vein injection as described (Inagaki et al., 2005). Mice did not have access to food throughout the 6 hr treatment, and livers were harvested and immediately frozen in liquid nitrogen. Microarray analyses were performed using the Mouse Genome 430A 2.0 array.
Project description:Background: Fibroblast growth factor-19 (FGF19) is an intestinal hormone that mediates postprandial metabolic responses in the liver. The unusual orphan nuclear receptor, Small Heterodimer Partner (SHP), acts as a co-repressor for many transcriptional factors and has been implicated in diverse biological pathways including FGF19-mediated repression of bile acid synthesis. To explore global functions of SHP in mediating FGF19 action, we identify genome-wide SHP binding sites in hepatic chromatin in mice treated with vehicle or FGF19 by ChIP-seq analysis. Results: The overall pattern of SHP binding sites between these two groups is similar, but SHP binding is enhanced at the sites by addition of FGF19. SHP binding is detected preferentially in promoter regions that are enriched in motifs for unexpected non-nuclear receptors. We observe global co-localization of SHP sites with published sites for SREBP-2, a master transcriptional activator of cholesterol biosynthesis. FGF19 increases functional interaction between endogenous SHP and SREBP-2 and inhibits SREBP-2 target genes, and these effects were blunted in SHP-knockout mice. Furthermore, FGF19-induced phosphorylation of SHP at Thr-55 is shown to be important for its functional interaction with SREBP-2 and reduction of liver/serum cholesterol levels. Conclusion: This study reveals SHP as a global transcriptional partner of SREBP-2 in regulation of sterol biosynthetic gene networks and provides a potential mechanism for cholesterol-lowering action of FGF19. Genome-wide SHP binding profiles in hepatic chromatin in mice under treatment of FGF19 or vehicle were generated using high throughput sequencing followed by chromatin immunoprecipitation.
Project description:Primary human hepatocytes were treated with recombinant FGF19 (n=3), CDCA (n=3), endogenously produced FGF19 (n=3), or vehicle controls (n=3+3). Total RNA was harvested and sequenced with a strand-specific paired end RNA-seq protocol.
Project description:DU145 prostate cancer cells were treated with 50 ng/ml FGF19 and 50 ug/ml heparin, or 10 ng/ml TNFalpha, or both drug treatment groups
Project description:We studied the effect of bile acid CDCA, FXR agonsit GW4064 and FGF19 on the expression levels of microRNA in cultured human primary hepatocytes
Project description:Cholesterol is an essential cell membrane component and precursor in metabolic pathways. Control of cholesterol levels is essential to human health. The endocrine hormone FGF19 potently inhibits CYP7A1, which controls a key step in cholesterol catabolism. However, the molecular mechanisms that integrate FGF19 with other cholesterol metabolic pathways are incompletely understood. Here we show that FGF19 and analogue promote HDL biogenesis and cholesterol efflux from the liver by selectively modulating liver X receptor signaling without inducing hepatic steatosis. We further identify ATP-binding cassette transporter A1 and FGFR4 as mediators of this effect. In dyslipidemic Apoe-/- mice fed a Western diet, treatment with FGF19 analogue dramatically reduced atherosclerotic lesion area in aortas. In healthy human volunteers, FGF19 analogue caused a placebo-adjusted increase in HDL cholesterol levels of 26% in seven days. These findings outline a regulatory role for FGF19 in cholesterol metabolism and advance our understanding of the mechanisms that coordinate sterol homeostasis. We used microarrays to detail the global programme of gene expression affected by FGF19 treatment in mice.
Project description:Farnesoid-X-Receptor (FXR) plays a central role in maintaining bile acid (BA) homeostasis by transcriptional control of numerous enterohepatic genes, including intestinal FGF19, a hormone that strongly represses hepatic BA synthesis. How activation of the FGF19 receptor at the membrane is transmitted to the nucleus for transcriptional regulation of BA levels and whether FGF19 signaling posttranslationally modulates function of FXR remain largely unknown. Here we show that FXR is phosphorylated at Y67 by non-receptor tyrosine kinase, Src, in response to postprandial FGF19, which is critical for its nuclear localization and transcriptional regulation of BA levels. Liver-specific expression of phospho-defective Y67F-FXR or Src-downregulation in mice result in impaired homeostatic responses to acute BA feeding, and exacerbate cholestatic pathologies upon drug-induced hepatobiliary insults. Also, the hepatic FGF19-Src-FXR pathway is defective in primary biliary cirrhosis patients. This study identifies Src-mediated FXR phosphorylation as a potential therapeutic target and biomarker for BA-related enterohepatic diseases.
Project description:Mouse FGF15 and human FGF19 are orthologous proteins that regulate bile acid metabolism. However, other hepatic functions of FGF15/19 are not well characterized.
Project description:Fibroblast growth factor 19 (FGF19) is a gut-derived peptide hormone that is produced following activation of Farnesoid X Receptor (FXR). FGF19 is secreted and signals to the liver, where it contributes to the homeostasis of bile acid (BA), lipid and carbohydrate metabolism. FGF19 is a promising therapeutic target in metabolic syndrome and cholestatic diseases, but enthusiasm for its use has been tempered by FGF19-mediated induction of proliferation and hepatocellular carcinoma. To inform future rational design of FGF19-variants, we have conducted temporal quantitative proteomic and gene expression analyses to identify FGF19-targets related to metabolism and proliferation. Mice were fasted for 16 hours, and injected with human FGF19 (1 mg/kg body weight) or vehicle. Liver protein extracts (containing 'light' lysine) were mixed 1:1 with a spike-in protein extract from 13C6-lysine metabolically labelled mouse liver (containing 'heavy' lysine) and analysed by LC-MS/MS. Our analyses provide a resource of FGF19 target proteins in the liver. 189 proteins were upregulated (≥ 1.5 folds) and 73 proteins were downregulated (≤ -1.5 folds) by FGF19. FGF19 treatment decreased the expression of proteins involved in fatty acid (FA) synthesis, i.e. Fabp5, Scd1, and Acsl3 and increased the expression of Acox1, involved in FA oxidation. As expected, FGF19 increased the expression of proteins known to drive proliferation (i.e. Tgfbi, Vcam1, Anxa2 and Hdlbp). Importantly, many of the FGF19 targets (i.e. Pdk4, Apoa4, Fas and Stat3) have a dual function in both metabolism and cell proliferation. Therefore, our findings challenge the development of FGF19-variants that uncouple full metabolic benefit from mitogenic potential.
Project description:Liver metastasis is the main cause of death for human colorectal cancer (CRC), thus effective biomarkers and therapeutic target of colorectal cancer liver metastasis (CRLM) are urgently needed. Here, we report that FGF19 mediated the polarization of hepatic stellate cells to inflammatory CAFs by activating the autocrine effect of IL-1α via JAK2-STAT3 pathway. FGF19-induced iCAFs produced complement C5a and IL-1β to enhance neutrophil extracellular traps (NETs) formation in liver metastases, which in turn accelerated the liver colonization of CRC cells.
Project description:Background: Fibroblast growth factor-19 (FGF19) is an intestinal hormone that mediates postprandial metabolic responses in the liver. The unusual orphan nuclear receptor, Small Heterodimer Partner (SHP), acts as a co-repressor for many transcriptional factors and has been implicated in diverse biological pathways including FGF19-mediated repression of bile acid synthesis. To explore global functions of SHP in mediating FGF19 action, we identify genome-wide SHP binding sites in hepatic chromatin in mice treated with vehicle or FGF19 by ChIP-seq analysis. Results: The overall pattern of SHP binding sites between these two groups is similar, but SHP binding is enhanced at the sites by addition of FGF19. SHP binding is detected preferentially in promoter regions that are enriched in motifs for unexpected non-nuclear receptors. We observe global co-localization of SHP sites with published sites for SREBP-2, a master transcriptional activator of cholesterol biosynthesis. FGF19 increases functional interaction between endogenous SHP and SREBP-2 and inhibits SREBP-2 target genes, and these effects were blunted in SHP-knockout mice. Furthermore, FGF19-induced phosphorylation of SHP at Thr-55 is shown to be important for its functional interaction with SREBP-2 and reduction of liver/serum cholesterol levels. Conclusion: This study reveals SHP as a global transcriptional partner of SREBP-2 in regulation of sterol biosynthetic gene networks and provides a potential mechanism for cholesterol-lowering action of FGF19.