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Jongsook Kim Kemper - One of the best experts on this subject based on the ideXlab platform.
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intestinal FGF15 19 physiologically repress hepatic lipogenesis in the late fed state by activating shp and dnmt3a
Nature Communications, 2020Co-Authors: Young Chae Kim, Sunmi Seok, Byron Kemper, Bo Kong, Yang Zhang, Grace L. Guo, Jongsook Kim KemperAbstract:Hepatic lipogenesis is normally tightly regulated but is aberrantly elevated in obesity. Fibroblast Growth Factor-15/19 (mouse FGF15, human FGF19) are bile acid-induced late fed-state gut hormones that decrease hepatic lipid levels by unclear mechanisms. We show that FGF15/19 and FGF15/19-activated Small Heterodimer Partner (SHP/NR0B2) have a role in transcriptional repression of lipogenesis. Comparative genomic analyses reveal that most of the SHP cistrome, including lipogenic genes repressed by FGF19, have overlapping CpG islands. FGF19 treatment or SHP overexpression in mice inhibits lipogenesis in a DNA methyltransferase-3a (DNMT3A)-dependent manner. FGF19-mediated activation of SHP via phosphorylation recruits DNMT3A to lipogenic genes, leading to epigenetic repression via DNA methylation. In non-alcoholic fatty liver disease (NAFLD) patients and obese mice, occupancy of SHP and DNMT3A and DNA methylation at lipogenic genes are low, with elevated gene expression. In conclusion, FGF15/19 represses hepatic lipogenesis by activating SHP and DNMT3A physiologically, which is likely dysregulated in NAFLD. Hepatic lipogenesis is a tightly regulated process, which is elevated in obesity. Here the authors report that FGF15/19, bile acid-induced gut hormones, repress lipogenic genes in the late fed-state by activating small heterodimer partner (SHP) and promoting SHP-dependent recruitment of DNA methyltransferase DNMT3A to lipogenic genes.
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phosphorylation of hepatic farnesoid x receptor by fgf19 signaling activated src maintains cholesterol levels and protects from atherosclerosis
Journal of Biological Chemistry, 2019Co-Authors: Sangwon Byun, Hyunkyung Jung, Jinjing Chen, Byron Kemper, Bo Kong, Jongsook Kim KemperAbstract:: The bile acid (BA) nuclear receptor, farnesoid X receptor (FXR/NR1H4), maintains metabolic homeostasis by transcriptional control of numerous genes, including an intestinal hormone, fibroblast growth factor-19 (FGF19; FGF15 in mice). Besides activation by BAs, the gene-regulatory function of FXR is also modulated by hormone or nutrient signaling-induced post-translational modifications. Recently, phosphorylation at Tyr-67 by the FGF15/19 signaling-activated nonreceptor tyrosine kinase Src was shown to be important for FXR function in BA homeostasis. Here, we examined the role of this FXR phosphorylation in cholesterol regulation. In both hepatic FXR-knockout and FXR-knockdown mice, reconstitution of FXR expression up-regulated cholesterol transport genes for its biliary excretion, including scavenger receptor class B member 1 (Scarb1) and ABC subfamily G member 8 (Abcg5/8), decreased hepatic and plasma cholesterol levels, and increased biliary and fecal cholesterol levels. Of note, these sterol-lowering effects were blunted by substitution of Phe for Tyr-67 in FXR. Moreover, consistent with Src's role in phosphorylating FXR, Src knockdown impaired cholesterol regulation in mice. In hypercholesterolemic apolipoprotein E-deficient mice, expression of FXR, but not Y67F-FXR, ameliorated atherosclerosis, whereas Src down-regulation exacerbated it. Feeding or treatment with an FXR agonist induced Abcg5/8 and Scarb1 expression in WT, but not FGF15-knockout, mice. Furthermore, FGF19 treatment increased occupancy of FXR at Abcg5/8 and Scarb1, expression of these genes, and cholesterol efflux from hepatocytes. These FGF19-mediated effects were blunted by the Y67F-FXR substitution or Src down-regulation or inhibition. We conclude that phosphorylation of hepatic FXR by FGF15/19-induced Src maintains cholesterol homeostasis and protects against atherosclerosis.
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small heterodimer partner and fibroblast growth factor 19 inhibit expression of npc1l1 in mouse intestine and cholesterol absorption
Gastroenterology, 2019Co-Authors: Sangwon Byun, Sunmi Seok, Eric H Xu, Byron Kemper, Jongsook Kim KemperAbstract:Background & Aims The nuclear receptor subfamily 0 group B member 2 (NR0B2, also called SHP) is expressed at high levels in the liver and intestine. Postprandial fibroblast growth factor 19 (human FGF19, mouse FGF15) signaling increases the transcriptional activity of SHP. We studied the functions of SHP and FGF19 in the intestines of mice, including their regulation of expression of the cholesterol transporter NPC1L1 )NPC1-like intracellular cholesterol transporter 1) and cholesterol absorption. Methods We performed histologic and biochemical analyses of intestinal tissues from C57BL/6 and SHP-knockout mice and performed RNA-sequencing analyses to identify genes regulated by SHP. The effects of fasting and refeeding on intestinal expression of NPC1L1 were examined in C57BL/6, SHP-knockout, and FGF15-knockout mice. Mice were given FGF19 daily for 1 week; fractional cholesterol absorption, cholesterol and bile acid (BA) levels, and composition of BAs were measured. Intestinal organoids were generated from C57BL/6 and SHP-knockout mice, and cholesterol uptake was measured. Luciferase reporter assays were performed with HT29 cells. Results We found that the genes that regulate lipid and ion transport in intestine, including NPC1L1, were up-regulated and that cholesterol absorption was increased in SHP-knockout mice compared with C57BL/6 mice. Expression of NPC1L1 was reduced in C57BL/6 mice after refeeding after fasting but not in SHP-knockout or FGF15-knockout mice. SHP-knockout mice had altered BA composition compared with C57BL/6 mice. FGF19 injection reduced expression of NPC1L1, decreased cholesterol absorption, and increased levels of hydrophilic BAs, including tauro-α- and -β-muricholic acids; these changes were not observed in SHP-knockout mice. SREBF2 (sterol regulatory element binding transcription factor 2), which regulates cholesterol, activated transcription of NPC1L1. FGF19 signaling led to phosphorylation of SHP, which inhibited SREBF2 activity. Conclusions Postprandial FGF19 and SHP inhibit SREBF2, which leads to repression of intestinal NPC1L1 expression and cholesterol absorption. Strategies to increase FGF19 signaling to activate SHP might be developed for treatment of hypercholesterolemia.
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a postprandial fgf19 shp lsd1 regulatory axis mediates epigenetic repression of hepatic autophagy
The EMBO Journal, 2017Co-Authors: Sangwon Byun, Jun Ichi Sadoshima, Byron Kemper, Bo Kong, Yang Zhang, Jongsook Kim KemperAbstract:Abstract Lysosome‐mediated autophagy is essential for cellular survival and homeostasis upon nutrient deprivation, but is repressed after feeding. Despite the emerging importance of transcriptional regulation of autophagy by nutrient‐sensing factors, the role for epigenetic control is largely unexplored. Here, we show that Small Heterodimer Partner (SHP) mediates postprandial epigenetic repression of hepatic autophagy by recruiting histone demethylase LSD1 in response to a late fed‐state hormone, FGF19 (hFGF19, mFGF15). FGF19 treatment or feeding inhibits macroautophagy, including lipophagy, but these effects are blunted in SHP‐null mice or LSD1‐depleted mice. In addition, feeding‐mediated autophagy inhibition is attenuated in FGF15‐null mice. Upon FGF19 treatment or feeding, SHP recruits LSD1 to CREB‐bound autophagy genes, including Tfeb, resulting in dissociation of CRTC2, LSD1‐mediated demethylation of gene‐activation histone marks H3K4‐me2/3, and subsequent accumulation of repressive histone modifications. Both FXR and SHP inhibit hepatic autophagy interdependently, but while FXR acts early, SHP acts relatively late after feeding, which effectively sustains postprandial inhibition of autophagy. This study demonstrates that the FGF19‐SHP‐LSD1 axis maintains homeostasis by suppressing unnecessary autophagic breakdown of cellular components, including lipids, under nutrient‐rich postprandial conditions.
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microrna 34a and impaired fgf19 21 signaling in obesity
Vitamins and Hormones Series, 2016Co-Authors: T Fu, Jongsook Kim KemperAbstract:Abstract The obesity epidemic and the urgent need for effective and safe drugs to treat obesity-related diseases have greatly increased research interest in the metabolic hormones, fibroblast growth factor-19 (FGF19, FGF15 in mice), and FGF21. FGF19 and FGF21 function as endocrine hormones that play key roles in energy metabolism and counteract obesity. Importantly, in obese humans and lab animals, circulating FGF19 and FGF21 levels are elevated, and metabolic actions of these hormones are impaired but the underlying mechanisms remained unknown. Recent microRNA (miR) studies have revealed that aberrantly elevated miR-34a in obesity directly targets β-Klotho, the obligate coreceptor for both FGF19 and FGF21, and attenuates metabolic signaling of these hormones. In this review, we will discuss recent findings in the miR and FGF19/21 fields, emphasizing the novel function of obesity-associated miR-34a in attenuation of FGF19/21 metabolic actions, and further discuss miRs, including miR-34a, as potential drug targets for obesity-related diseases.
Makoto Akashi - One of the best experts on this subject based on the ideXlab platform.
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fibroblast growth factor 12 fgf12 translocation into intestinal epithelial cells is dependent on a novel cell penetrating peptide domain involvement of internalization in the in vivo role of exogenous fgf12
Journal of Biological Chemistry, 2011Co-Authors: Fumiaki Nakayama, Sachiko Umeda, Viktor Meineke, Toru Imamura, Takeshi Yasuda, Masahiro Asada, Makoto AkashiAbstract:Abstract The extracellular effect of fibroblast growth factor-12 (FGF12) remains unknown because FGF12 cannot activate any fibroblast growth factor receptors (FGFRs), and FGF12 is not currently thought to be released from cells. We reported previously that FGF12 plays an intracellular role in the inhibition of radiation-induced apoptosis. In this study, we demonstrated that recombinant FGF12 was able to be internalized into the cytoplasm of a rat intestinal epithelial cell line, IEC6, and this process was dependent on two novel cell-penetrating peptide (CPP) domains (CPP-M and CPP-C). In particular, CPP-C, composed of ∼10 amino acids, was identified as a specific domain of FGF12 and its subfamily in the C-terminal region (residues 140–149), although CPP-M was a common domain in the internal region of the FGF family. The absence of CPP-C from FGF12 or a mutation (E142L) in the CPP-C domain drastically reduced the internalization of FGF12 into cells. Therefore, CPP-C played an essential role in the internalization of FGF12. In addition, CPP-C was able to deliver other polypeptides into cells as a CPP because an FGF1/CPP-C chimeric protein was internalized into IEC6 cells more efficiently than wild-type FGF1. Finally, intraperitoneally added FGF12 inhibited radiation-induced apoptosis in the intestinal epithelial cells of BALB/c mice, and deletion of the CPP-C domain decreased the inhibition of the apoptosis. These findings suggest that exogenous FGF12 can play a role in tissues by translocating into cells through the plasma membrane, and the availability of this novel CPP provides a new tool for the intracellular delivery of bioactive molecules.
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fibroblast growth factor 12 fgf12 translocation into intestinal epithelial cells is dependent on a novel cell penetrating peptide domain involvement of internalization in the in vivo role of exogenous fgf12
Journal of Biological Chemistry, 2011Co-Authors: Fumiaki Nakayama, Sachiko Umeda, Viktor Meineke, Toru Imamura, Takeshi Yasuda, Masahiro Asada, Makoto AkashiAbstract:Abstract The extracellular effect of fibroblast growth factor-12 (FGF12) remains unknown because FGF12 cannot activate any fibroblast growth factor receptors (FGFRs), and FGF12 is not currently thought to be released from cells. We reported previously that FGF12 plays an intracellular role in the inhibition of radiation-induced apoptosis. In this study, we demonstrated that recombinant FGF12 was able to be internalized into the cytoplasm of a rat intestinal epithelial cell line, IEC6, and this process was dependent on two novel cell-penetrating peptide (CPP) domains (CPP-M and CPP-C). In particular, CPP-C, composed of ∼10 amino acids, was identified as a specific domain of FGF12 and its subfamily in the C-terminal region (residues 140–149), although CPP-M was a common domain in the internal region of the FGF family. The absence of CPP-C from FGF12 or a mutation (E142L) in the CPP-C domain drastically reduced the internalization of FGF12 into cells. Therefore, CPP-C played an essential role in the internalization of FGF12. In addition, CPP-C was able to deliver other polypeptides into cells as a CPP because an FGF1/CPP-C chimeric protein was internalized into IEC6 cells more efficiently than wild-type FGF1. Finally, intraperitoneally added FGF12 inhibited radiation-induced apoptosis in the intestinal epithelial cells of BALB/c mice, and deletion of the CPP-C domain decreased the inhibition of the apoptosis. These findings suggest that exogenous FGF12 can play a role in tissues by translocating into cells through the plasma membrane, and the availability of this novel CPP provides a new tool for the intracellular delivery of bioactive molecules.
Iker Uriarte - One of the best experts on this subject based on the ideXlab platform.
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FGF15 19 is required for adipose tissue plasticity in response to thermogenic adaptations
Molecular metabolism, 2021Co-Authors: Samantha Moronros, Iker Uriarte, Carmen Berasain, Matias A Avila, Monica Sabatermasdeu, Jose Maria Morenonavarrete, Jose Manuel Fernandezreal, Marta Giralt, Francesc VillarroyaAbstract:Abstract Objective To determine the role of enterokine FGF15/19 in adipose tissue thermogenic adaptations. Methods Circulating FGF19 and gene expression (qRT-PCR) levels were assessed in subcutaneous adipose tissue from obese human patients. Effects of experimentally increased FGF15 and FGF19 levels in vivo were determined in mice using adenoviral and adeno-associated vectors. Adipose tissues were characterized in FGF15-null mice under distinct cold-related thermogenic challenges. The analyses spanned metabolic profiling, tissue characterization, histology, gene expression, and immunoblot assays. Results In humans, FGF19 levels are directly associated with UCP1 gene expression in subcutaneous adipose tissue. Experimental increases in FGF15 or FGF19 induced white fat browning in mice as demonstrated by the appearance of multilocular beige cells and markers indicative of a beige phenotype, including increased UCP1 protein levels. Mice lacking FGF15 showed markedly impaired white adipose tissue browning and a mild reduction in parameters indicative of BAT activity in response to cold-induced environmental thermogenic challenges. This was concomitant with signs of altered systemic metabolism, such as reduced glucose tolerance and impaired cold-induced insulin sensitization. Conclusions Enterokine FGF15/19 is a key factor required for adipose tissue plasticity in response to thermogenic adaptations.
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FGF15 19 is required for adipose tissue plasticity in response to thermogenic adaptation
Molecular metabolism, 2020Co-Authors: Iker Uriarte, Samantha Moronros, Carmen Berasain, Matias A Avila, Monica Sabatermasdeu, Jose Maria MorenonavarreteAbstract:Abstract Objective To determine the role of the enterokine, FGF15/19, in adipose tissue thermogenic adaptations. Methods Circulating FGF19 and gene expression (qRT-PCR) levels were assessed in subcutaneous adipose tissue from human patients with obesity. Effects of experimentally increased FGF15 and FGF19 levels in vivo were determined in mice using adenoviral and adeno-associated vectors. Adipose tissues were characterized in FGF15-null mice under distinct cold-related thermogenic challenges. The analyses performed spanned metabolic profiling, tissue characterization, histology, gene expression and immunoblot assays. Results In humans, FGF19 levels are directly associated with UCP1 gene expression in subcutaneous adipose tissue. Experimental increases of FGF15 or FGF19 induced white fat browning in mice, as evidence by the appearance of multilocular beige cells and markers indicative of a beige phenotype, including increased UCP1 protein levels. Mice lacking FGF15 showed markedly impaired white adipose tissue browning and a mild reduction in parameters indicative of BAT activity in response to cold-induced environmental thermogenic challenges. This was concomitant with signs of altered systemic metabolism, such as reduced glucose tolerance and impaired cold-induced insulin sensitization. Conclusions The enterokine FGF15/19 is a key factor required for adipose tissue plasticity in response to thermogenic adaptations.
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fibroblast growth factor 15 19 FGF15 19 protects from diet induced hepatic steatosis development of an fgf19 based chimeric molecule to promote fatty liver regeneration
Gut, 2017Co-Authors: Gloria Alvarezsola, Ujue M Latasa, Marina Barcenavarela, Maddalen Jimenez, Maite G Fernandezbarrena, Maria Elizalde, Iker Uriarte, Haisul C Y Chang, Raquel Urtasun, Roberto BarberoAbstract:Objective Fibroblast growth factor 15/19 (FGF15/19), an enterokine that regulates synthesis of hepatic bile acids (BA), has been proposed to influence fat metabolism. Without FGF15/19, mouse liver regeneration after partial hepatectomy (PH) is severely impaired. We studied the role of FGF15/19 in response to a high fat diet (HFD) and its regulation by saturated fatty acids. We developed a fusion molecule encompassing FGF19 and apolipoprotein A-I, termed Fibapo, and evaluated its pharmacological properties in fatty liver regeneration. Design FGF15 −/− mice were fed a HFD. Liver fat and the expression of fat metabolism and endoplasmic reticulum (ER) stress-related genes were measured. Influence of palmitic acid (PA) on FGF15/19 expression was determined in mice and in human liver cell lines. In vivo half-life and biological activity of Fibapo and FGF19 were compared. Hepatoprotective and proregenerative activities of Fibapo were evaluated in obese db/db mice undergoing PH. Results Hepatosteatosis and ER stress were exacerbated in HFD-fed FGF15 −/− mice. Hepatic expression of Pparγ2 was elevated in FGF15 −/− mice, being reversed by FGF19 treatment. PA induced FGF15/19 expression in mouse ileum and human liver cells, and FGF19 protected from PA-mediated ER stress and cytotoxicity. Fibapo reduced liver BA and lipid accumulation, inhibited ER stress and showed enhanced half-life. Fibapo provided increased db/db mice survival and improved regeneration upon PH. Conclusions FGF15/19 is essential for hepatic metabolic adaptation to dietary fat being a physiological regulator of Pparγ2 expression . Perioperative administration of Fibapo improves fatty liver regeneration.
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ileal FGF15 contributes to fibrosis associated hepatocellular carcinoma development
International Journal of Cancer, 2015Co-Authors: Ujue M Latasa, Maite G Fernandezbarrena, Maria Elizalde, Iker Uriarte, Raquel Urtasun, Simone Carotti, Oihane Garciairigoyen, Umberto VespasianigentilucciAbstract:Fibroblast growth factor 15 (FGF15), FGF19 in humans, is a gut-derived hormone and a key regulator of bile acids and carbohydrate metabolism. FGF15 also participates in liver regeneration after partial hepatectomy inducing hepatocellular proliferation. FGF19 is overexpressed in a significant proportion of human hepatocellular carcinomas (HCC), and activation of its receptor FGFR4 promotes HCC cell growth. Here we addressed for the first time the role of endogenous FGF15 in hepatocarcinogenesis. FGF15(+/+) and FGF15(-/-) mice were subjected to a clinically relevant model of liver inflammation and fibrosis-associated carcinogenesis. FGF15(-/-) mice showed less and smaller tumors, and histological neoplastic lesions were also smaller than in FGF15(+/+) animals. Importantly, ileal FGF15 mRNA expression was enhanced in mice undergoing carcinogenesis, but at variance with human HCC it was not detected in liver or HCC tissues, while circulating FGF15 protein was clearly upregulated. Hepatocellular proliferation was also reduced in FGF15(-/-) mice, which also expressed lower levels of the HCC marker alpha-fetoprotein (AFP). Interestingly, lack of FGF15 resulted in attenuated fibrogenesis. However, in vitro experiments showed that liver fibrogenic stellate cells were not direct targets for FGF15/FGF19. Conversely we demonstrate that FGF15/FGF19 induces the expression of the pro-fibrogenic and pro-tumorigenic connective tissue growth factor (CTGF) in hepatocytes. These findings suggest the existence of an FGF15-triggered CTGF-mediated paracrine action on stellate cells, and an amplification mechanism for the hepatocarcinogenic effects of FGF15 via CTGF production. In summary, our observations indicate that ileal FGF15 may contribute to HCC development in a context of chronic liver injury and fibrosis.
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identification of fibroblast growth factor 15 as a novel mediator of liver regeneration and its application in the prevention of post resection liver failure in mice
Gut, 2013Co-Authors: Iker Uriarte, Maite G Fernandezbarrena, Haisul C Y Chang, Simone Carotti, Sergio Morini, Umberto Vespasianigentilucci, Maria J Monte, Maria U Latasa, Eva Vicente, Axel R ConcepcionAbstract:Objective Cholestasis is associated with increased liver injury and morbidity after partial hepatectomy (PH), yet bile acids (BAs) are emerging as important mediators of liver regeneration. Fibroblast growth factor 15 (FGF15, human FGF19) is a BA-induced ileum-derived enterokine that governs BA metabolism. We evaluated the relevance of FGF15 in the preservation of BA homeostasis after PH and its potential role in the regenerative process. Design Liver regeneration after PH was studied in FGF15 −/− and FGF15 +/+ mice. The effects of the BA sequestrant cholestyramine and adenovirally delivered FGF15 were examined in this model. The role of FGF15 in BA-induced liver growth was tested in FGF15 −/− mice upon cholic acid (CA) feeding. The direct mitogenic effect of FGF15 was evaluated in cultured mouse hepatocytes and cholangiocytes. Results FGF15 −/− mice showed marked liver injury and mortality after PH accompanied by persistently elevated intrahepatic BA levels. Cholestyramine feeding and adenovirally delivered FGF15 reduced BA levels and significantly prevented this lethal outcome. FGF15 also reduced mortality after extensive hepatectomy in FGF15 +/+ animals. Liver growth elicited by CA feeding was significantly diminished in FGF15 −/− mice. Proliferation of hepatocytes and cholangiocytes was also noticeably reduced in CA-fed FGF15 −/− mice. FGF15 induced intracellular signalling and proliferation of cultured hepatocytes and cholangiocytes. Conclusions FGF15 is necessary to maintain BA homeostasis and prevent liver injury during liver regeneration. Moreover, FGF15 is an essential mediator of the liver growth-promoting effects of BA. Preoperative administration of this enterokine to patients undergoing liver resection might be useful to reduce damage and foster regeneration.
Fumiaki Nakayama - One of the best experts on this subject based on the ideXlab platform.
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fibroblast growth factor 12 fgf12 translocation into intestinal epithelial cells is dependent on a novel cell penetrating peptide domain involvement of internalization in the in vivo role of exogenous fgf12
Journal of Biological Chemistry, 2011Co-Authors: Fumiaki Nakayama, Sachiko Umeda, Viktor Meineke, Toru Imamura, Takeshi Yasuda, Masahiro Asada, Makoto AkashiAbstract:Abstract The extracellular effect of fibroblast growth factor-12 (FGF12) remains unknown because FGF12 cannot activate any fibroblast growth factor receptors (FGFRs), and FGF12 is not currently thought to be released from cells. We reported previously that FGF12 plays an intracellular role in the inhibition of radiation-induced apoptosis. In this study, we demonstrated that recombinant FGF12 was able to be internalized into the cytoplasm of a rat intestinal epithelial cell line, IEC6, and this process was dependent on two novel cell-penetrating peptide (CPP) domains (CPP-M and CPP-C). In particular, CPP-C, composed of ∼10 amino acids, was identified as a specific domain of FGF12 and its subfamily in the C-terminal region (residues 140–149), although CPP-M was a common domain in the internal region of the FGF family. The absence of CPP-C from FGF12 or a mutation (E142L) in the CPP-C domain drastically reduced the internalization of FGF12 into cells. Therefore, CPP-C played an essential role in the internalization of FGF12. In addition, CPP-C was able to deliver other polypeptides into cells as a CPP because an FGF1/CPP-C chimeric protein was internalized into IEC6 cells more efficiently than wild-type FGF1. Finally, intraperitoneally added FGF12 inhibited radiation-induced apoptosis in the intestinal epithelial cells of BALB/c mice, and deletion of the CPP-C domain decreased the inhibition of the apoptosis. These findings suggest that exogenous FGF12 can play a role in tissues by translocating into cells through the plasma membrane, and the availability of this novel CPP provides a new tool for the intracellular delivery of bioactive molecules.
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fibroblast growth factor 12 fgf12 translocation into intestinal epithelial cells is dependent on a novel cell penetrating peptide domain involvement of internalization in the in vivo role of exogenous fgf12
Journal of Biological Chemistry, 2011Co-Authors: Fumiaki Nakayama, Sachiko Umeda, Viktor Meineke, Toru Imamura, Takeshi Yasuda, Masahiro Asada, Makoto AkashiAbstract:Abstract The extracellular effect of fibroblast growth factor-12 (FGF12) remains unknown because FGF12 cannot activate any fibroblast growth factor receptors (FGFRs), and FGF12 is not currently thought to be released from cells. We reported previously that FGF12 plays an intracellular role in the inhibition of radiation-induced apoptosis. In this study, we demonstrated that recombinant FGF12 was able to be internalized into the cytoplasm of a rat intestinal epithelial cell line, IEC6, and this process was dependent on two novel cell-penetrating peptide (CPP) domains (CPP-M and CPP-C). In particular, CPP-C, composed of ∼10 amino acids, was identified as a specific domain of FGF12 and its subfamily in the C-terminal region (residues 140–149), although CPP-M was a common domain in the internal region of the FGF family. The absence of CPP-C from FGF12 or a mutation (E142L) in the CPP-C domain drastically reduced the internalization of FGF12 into cells. Therefore, CPP-C played an essential role in the internalization of FGF12. In addition, CPP-C was able to deliver other polypeptides into cells as a CPP because an FGF1/CPP-C chimeric protein was internalized into IEC6 cells more efficiently than wild-type FGF1. Finally, intraperitoneally added FGF12 inhibited radiation-induced apoptosis in the intestinal epithelial cells of BALB/c mice, and deletion of the CPP-C domain decreased the inhibition of the apoptosis. These findings suggest that exogenous FGF12 can play a role in tissues by translocating into cells through the plasma membrane, and the availability of this novel CPP provides a new tool for the intracellular delivery of bioactive molecules.
Bo Kong - One of the best experts on this subject based on the ideXlab platform.
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intestinal FGF15 19 physiologically repress hepatic lipogenesis in the late fed state by activating shp and dnmt3a
Nature Communications, 2020Co-Authors: Young Chae Kim, Sunmi Seok, Byron Kemper, Bo Kong, Yang Zhang, Grace L. Guo, Jongsook Kim KemperAbstract:Hepatic lipogenesis is normally tightly regulated but is aberrantly elevated in obesity. Fibroblast Growth Factor-15/19 (mouse FGF15, human FGF19) are bile acid-induced late fed-state gut hormones that decrease hepatic lipid levels by unclear mechanisms. We show that FGF15/19 and FGF15/19-activated Small Heterodimer Partner (SHP/NR0B2) have a role in transcriptional repression of lipogenesis. Comparative genomic analyses reveal that most of the SHP cistrome, including lipogenic genes repressed by FGF19, have overlapping CpG islands. FGF19 treatment or SHP overexpression in mice inhibits lipogenesis in a DNA methyltransferase-3a (DNMT3A)-dependent manner. FGF19-mediated activation of SHP via phosphorylation recruits DNMT3A to lipogenic genes, leading to epigenetic repression via DNA methylation. In non-alcoholic fatty liver disease (NAFLD) patients and obese mice, occupancy of SHP and DNMT3A and DNA methylation at lipogenic genes are low, with elevated gene expression. In conclusion, FGF15/19 represses hepatic lipogenesis by activating SHP and DNMT3A physiologically, which is likely dysregulated in NAFLD. Hepatic lipogenesis is a tightly regulated process, which is elevated in obesity. Here the authors report that FGF15/19, bile acid-induced gut hormones, repress lipogenic genes in the late fed-state by activating small heterodimer partner (SHP) and promoting SHP-dependent recruitment of DNA methyltransferase DNMT3A to lipogenic genes.
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direct and indirect effects of fibroblast growth factor fgf 15 and fgf19 on liver fibrosis development
Hepatology, 2020Co-Authors: Justin D Schumacher, Daniel Rizzolo, Laura E Armstrong, Monica D Chow, Jason Wu, Bo Kong, Michael J. GoedkenAbstract:: Farnesoid X receptor (FXR) induces fibroblast growth factor 15 (FGF15; human ortholog FGF19) in the gut to potently inhibit bile acid (BA) synthesis in the liver. FXR activation in hepatic stellate cells (HSCs) reduces liver fibrosis (LF). FGF15-/- mice develop attenuated LF, but the underlying mechanisms for this protection are unclear. We hypothesized that FGF15/19 functions as a profibrotic mediator or mitogen to HSCs and increased BAs in FGF15-/- mice leads to enhanced FXR activation in HSCs, subsequently reducing fibrogenesis. In this study, complimentary in vivo and in vitro approaches were used: (1) CCl4 -induced LF model in wild type (WT), FGF15-/- , and FGF15 transgenic (TG) mice with BA levels modulated by feeding cholestyramine- or cholic acid-containing diets; (2) analysis of primary HSCs isolated from WT and FGF15-/- mice; and (3) treatment of a human HSC line, LX-2, with FXR activators and/or recombinant FGF19 protein. The results showed that FGF15-/- mice had lower basal collagen expression, which was increased by BA sequestration. CCl4 induced fibrosis with similar severity in all genotypes; however, cholestyramine increased fibrosis severity only in FGF15-/- mice. HSCs from FGF15-/- mice showed increased FXR activity and reduced expression of profibrotic mediators. In LX-2 cells, FXR activation increased peroxisome proliferator-activated receptor gamma activity and reduced proliferation. FGF19 activated both signal transducer and activator of transcription 3 and c-Jun N-terminal kinase pathways and reduced nuclear factor kappa-light-chain-enhancer of activated B cells signaling without increasing fibrogenic gene expression or cell proliferation. Conclusion: FGF15/19 does not act as a direct profibrotic mediator or mitogen to HSCs in our models, and the protection against fibrosis by FGF15 deficiency may be mediated through increased BA activation of FXR in HSCs.
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phosphorylation of hepatic farnesoid x receptor by fgf19 signaling activated src maintains cholesterol levels and protects from atherosclerosis
Journal of Biological Chemistry, 2019Co-Authors: Sangwon Byun, Hyunkyung Jung, Jinjing Chen, Byron Kemper, Bo Kong, Jongsook Kim KemperAbstract:: The bile acid (BA) nuclear receptor, farnesoid X receptor (FXR/NR1H4), maintains metabolic homeostasis by transcriptional control of numerous genes, including an intestinal hormone, fibroblast growth factor-19 (FGF19; FGF15 in mice). Besides activation by BAs, the gene-regulatory function of FXR is also modulated by hormone or nutrient signaling-induced post-translational modifications. Recently, phosphorylation at Tyr-67 by the FGF15/19 signaling-activated nonreceptor tyrosine kinase Src was shown to be important for FXR function in BA homeostasis. Here, we examined the role of this FXR phosphorylation in cholesterol regulation. In both hepatic FXR-knockout and FXR-knockdown mice, reconstitution of FXR expression up-regulated cholesterol transport genes for its biliary excretion, including scavenger receptor class B member 1 (Scarb1) and ABC subfamily G member 8 (Abcg5/8), decreased hepatic and plasma cholesterol levels, and increased biliary and fecal cholesterol levels. Of note, these sterol-lowering effects were blunted by substitution of Phe for Tyr-67 in FXR. Moreover, consistent with Src's role in phosphorylating FXR, Src knockdown impaired cholesterol regulation in mice. In hypercholesterolemic apolipoprotein E-deficient mice, expression of FXR, but not Y67F-FXR, ameliorated atherosclerosis, whereas Src down-regulation exacerbated it. Feeding or treatment with an FXR agonist induced Abcg5/8 and Scarb1 expression in WT, but not FGF15-knockout, mice. Furthermore, FGF19 treatment increased occupancy of FXR at Abcg5/8 and Scarb1, expression of these genes, and cholesterol efflux from hepatocytes. These FGF19-mediated effects were blunted by the Y67F-FXR substitution or Src down-regulation or inhibition. We conclude that phosphorylation of hepatic FXR by FGF15/19-induced Src maintains cholesterol homeostasis and protects against atherosclerosis.
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a postprandial fgf19 shp lsd1 regulatory axis mediates epigenetic repression of hepatic autophagy
The EMBO Journal, 2017Co-Authors: Sangwon Byun, Jun Ichi Sadoshima, Byron Kemper, Bo Kong, Yang Zhang, Jongsook Kim KemperAbstract:Abstract Lysosome‐mediated autophagy is essential for cellular survival and homeostasis upon nutrient deprivation, but is repressed after feeding. Despite the emerging importance of transcriptional regulation of autophagy by nutrient‐sensing factors, the role for epigenetic control is largely unexplored. Here, we show that Small Heterodimer Partner (SHP) mediates postprandial epigenetic repression of hepatic autophagy by recruiting histone demethylase LSD1 in response to a late fed‐state hormone, FGF19 (hFGF19, mFGF15). FGF19 treatment or feeding inhibits macroautophagy, including lipophagy, but these effects are blunted in SHP‐null mice or LSD1‐depleted mice. In addition, feeding‐mediated autophagy inhibition is attenuated in FGF15‐null mice. Upon FGF19 treatment or feeding, SHP recruits LSD1 to CREB‐bound autophagy genes, including Tfeb, resulting in dissociation of CRTC2, LSD1‐mediated demethylation of gene‐activation histone marks H3K4‐me2/3, and subsequent accumulation of repressive histone modifications. Both FXR and SHP inhibit hepatic autophagy interdependently, but while FXR acts early, SHP acts relatively late after feeding, which effectively sustains postprandial inhibition of autophagy. This study demonstrates that the FGF19‐SHP‐LSD1 axis maintains homeostasis by suppressing unnecessary autophagic breakdown of cellular components, including lipids, under nutrient‐rich postprandial conditions.
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soluble expression of disulfide bond containing proteins FGF15 and fgf19 in the cytoplasm of escherichia coli
PLOS ONE, 2014Co-Authors: Bo KongAbstract:Fibroblast growth factor 19 (FGF19) is the human ortholog of mouse FGF15, and both proteins function as an endocrine signal to regulate various liver functions. FGF15/FGF19 protein contains two disulfide bonds. It is unfavorable to form disulfide bonds in Escherichia coli (E. coli) cytoplasm because of the bacterial cytoplasmic reducing environment. Modification of the cytoplasmic reducing environment and/or co-expression of protein chaperones are common strategies to express disulfide bond containing proteins in E. coli. In the current study, we report a method to produce soluble FGF15/FGF19 protein in cytoplasm of E. coli. Several commercial available strains with the disruption of thiol-redox pathways, and/or co-expression of redoxase or refolding chaperones were used to develop this novel method for expression of FGF15/FGF19 in E. coli. Mutation of the thiol-disulfide bond reducing pathway in E. coli or N-terminal fusion of thioredox (TRX) alone is not enough to support disulfide bond formation in FGF15/19 proteins. However, TRX fusion protein improved FGF19 solubility in strains of thiol-redox system mutants. In addition, DsbC co-expressed in thiol-redox system mutants alone improved and further enhanced FGF19 solubility with combination of TRX fusion tag. The soluble FGF19 proteins were easily purified through Ni-NTA affinity chromatography and anion exchange chromatography, and the purified protein maintained its biological activities, confirmed by suppressing hepatic Cyp7a1 gene transcription in mice and by activating ERK1/2 signaling pathway in HepG2 cells. In contrast, soluble FGF15 protein in cytoplasm remained very low using these strategies. In summary, we have successfully developed a method to express functional FGF19 protein in prokaryotic cells, and this strategy may be adapted for the expression of other disulfide-containing proteins.