Estrogen-Wnt signaling cascade regulates expression of hepatic fibroblast growth Factor 21

Author(s):  
Yasaman Badakhshi ◽  
Weijuan Shao ◽  
Dinghui Liu ◽  
Lili Tian ◽  
Juan Pang ◽  
...  

We have generated the transgenic mouse line LTCFDN in which dominant negative TCF7L2 (TCF7L2DN) is specifically expressed in the liver during adulthood. Male but not female LTCFDN mice showed elevated hepatic and plasma TG levels, indicating the existence of estrogen-β-cat/TCF signaling cascade that regulates hepatic lipid homeostasis. We show here that hepatic FGF21 expression was reduced in male but not in female LTCFDN mice. The reduction was not associated with altered hepatic expression of peroxisome proliferator-activated receptor α (PPARα). In mouse primary hepatocytes (MPH), Wnt-3a treatment increased FGF21 expression in the presence of PPARα inhibitor. Results from our luciferase-reporter assay and chromatin immunoprecipitation suggest that evolutionarily conserved TCF binding motifs (TCFBs) on Fgf21 promoter mediate Wnt-3a induced Fgf21 transactivation. Female mice showed reduced hepatic FGF21 production and circulating FGF21 level following ovariectomy (OVX), associated with reduced hepatic TCF expression and β-catenin S675 phosphorylation. Finally, in MPH, estradiol (E2) treatment enhanced FGF21 expression, as well as binding of TCF7L2 and RNA polymerase II to the Fgf21 promoter; and the enhancement can be attenuated by the G-protein-coupled estrogen receptor 1 (GPER) antagonist G15. Our observations hence indicate that hepatic FGF21 is among the effectors of the newly recognized E2-β-cat/TCF signaling cascade.

2010 ◽  
Vol 299 (4) ◽  
pp. E607-E614 ◽  
Author(s):  
Eric D. Berglund ◽  
Li Kang ◽  
Robert S. Lee-Young ◽  
Clinton M. Hasenour ◽  
Daniel G. Lustig ◽  
...  

Hepatic glucagon action increases in response to accelerated metabolic demands and is associated with increased whole body substrate availability, including circulating lipids. The hypothesis that increases in hepatic glucagon action stimulate AMP-activated protein kinase (AMPK) signaling and peroxisome proliferator-activated receptor-α (PPARα) and fibroblast growth factor 21 (FGF21) expression in a manner modulated by fatty acids was tested in vivo. Wild-type ( gcgr+/+) and glucagon receptor-null ( gcgr−/−) littermate mice were studied using an 18-h fast, exercise, and hyperglucagonemic-euglycemic clamps plus or minus increased circulating lipids. Fasting and exercise in gcgr+/+, but not gcgr−/− mice, increased hepatic phosphorylated AMPKα at threonine 172 (p-AMPKThr172) and PPARα and FGF21 mRNA. Clamp results in gcgr+/+ mice demonstrate that hyperlipidemia does not independently impact or modify glucagon-stimulated increases in hepatic AMP/ATP, p-AMPKThr172, or PPARα and FGF21 mRNA. It blunted glucagon-stimulated acetyl-CoA carboxylase phosphorylation, a downstream target of AMPK, and accentuated PPARα and FGF21 expression. All effects were absent in gcgr−/− mice. These findings demonstrate that glucagon exerts a critical regulatory role in liver to stimulate pathways linked to lipid metabolism in vivo and shows for the first time that effects of glucagon on PPARα and FGF21 expression are amplified by a physiological increase in circulating lipids.


2015 ◽  
Vol 29 (2) ◽  
pp. 213-223 ◽  
Author(s):  
Rucha Patel ◽  
Angie L. Bookout ◽  
Lilia Magomedova ◽  
Bryn M. Owen ◽  
Giulia P. Consiglio ◽  
...  

Abstract Hormones such as fibroblast growth factor 21 (FGF21) and glucocorticoids (GCs) play crucial roles in coordinating the adaptive starvation response. Here we examine the interplay between these hormones. It was previously shown that FGF21 induces corticosterone levels in mice by acting on the brain. We now show that this induces the expression of genes required for GC synthesis in the adrenal gland. FGF21 also increases corticosterone secretion from the adrenal in response to ACTH. We further show that the relationship between FGF21 and GCs is bidirectional. GCs induce Fgf21 expression in the liver by acting on the GC receptor (GR). The GR binds in a ligand-dependent manner to a noncanonical GR response element located approximately 4.4 kb upstream of the Fgf21 transcription start site. The GR cooperates with the nuclear fatty acid receptor, peroxisome proliferator-activated receptor-α, to stimulate Fgf21 transcription. GR and peroxisome proliferator-activated receptor-α ligands have additive effects on Fgf21 expression both in vivo and in primary cultures of mouse hepatocytes. We conclude that FGF21 and GCs regulate each other's production in a feed-forward loop and suggest that this provides a mechanism for bypassing negative feedback on the hypothalamic-pituitary-adrenal axis to allow sustained gluconeogenesis during starvation.


2019 ◽  
Vol 62 (4) ◽  
pp. 187-196 ◽  
Author(s):  
Qi Zhang ◽  
Qin Zhu ◽  
Ruyuan Deng ◽  
Feiye Zhou ◽  
Linlin Zhang ◽  
...  

Fibroblast growth factor 21 (FGF21) plays an important role in the regulation of lipid and glucose metabolism. MS-275, as a class I-specific histone deacetylase (HDAC) inhibitor, has also been reported to affect energy metabolism. In this current study, we investigated the effects of MS-275 on hepatic FGF21 expression in vitro and in vivo and explored whether cAMP-responsive element-binding protein H (CREBH) was involved in the action of MS-275. Our results showed that MS-275 stimulated hepatic FGF21 mRNA and protein expressions in a dose- and time-dependent manner, as well as FGF21 secretion in primary mouse hepatocytes. Serum concentration and hepatic expression of FGF21 were elevated after injection of MS-275, along with increased expressions of genes involved in fatty acid oxidation and ketogenic production (peroxisome proliferator-activated receptor gammacoactivator1α, PGC-1α; carnitine palmitoyl-transferase 1a, CPT1a; 3-hydroxy-3-methylglutaryl-CoA synthase 2, Hmgcs2) as well as improved blood lipid profile. As a proved transcription factor of FGF21, the expression of CREBH was initiated by MS-275, with increased histone H3 lysine 18 acetylation (H3K18ac) signals and hepatocyte nuclear factor 4 alpha (HNF-4α) recruitment in CREBH promoter. Adenovirus-mediated knockdown of CREBH abolished MS-275-induced hepatic FGF21 and lipid metabolism-related gene expressions. These results suggest that MS-275 induces hepatic FGF21 by H3K18ac-mediated CREBH expression.


PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Allan Ramirez ◽  
Erin N. Ballard ◽  
Jesse Roman

Transforming growth factorβ1 (TGFβ1) promotes fibrosis by, among other mechanisms, activating quiescent fibroblasts into myofibroblasts and increasing the expression of extracellular matrices. Recent work suggests that peroxisome proliferator-activated receptorγ(PPARγ) is a negative regulator of TGFβ1-induced fibrotic events. We, however, hypothesized that antifibrotic pathways mediated by PPARγare influenced by TGFβ1, causing an imbalance towards fibrogenesis. Consistent with this, primary murine primary lung fibroblasts responded to TGFβ1 with a sustained downregulation of PPARγtranscripts. This effect was dampened in lung fibroblasts deficient in Smad3, a transcription factor that mediates many of the effects of TGFβ1. Paradoxically, TGFβ1 stimulated the activation of the PPARγgene promoter and induced the phosphorylation of PPARγin primary lung fibroblasts. The ability of TGFβ1 to modulate the transcriptional activity of PPARγwas then tested in NIH/3T3 fibroblasts containing a PPARγ-responsive luciferase reporter. In these cells, stimulation of TGFβ1 signals with a constitutively active TGFβ1 receptor transgene blunted PPARγ-dependent reporter expression induced by troglitazone, a PPARγactivator. Overexpression of PPARγprevented TGFβ1 repression of troglitazone-induced PPARγ-dependent gene transcription, whereas coexpression of PPARγand Smad3 transgenes recapitulated the TGFβ1 effects. We conclude that modulation of PPARγis controlled by TGFβ1, in part through Smad3 signals, involving regulation of PPARγexpression and transcriptional potential.


2007 ◽  
Vol 293 (1) ◽  
pp. R70-R77 ◽  
Author(s):  
Sebastian Luci ◽  
Beatrice Giemsa ◽  
Holger Kluge ◽  
Klaus Eder

This study investigated the effect of clofibrate treatment on expression of target genes of peroxisome proliferator-activated receptor (PPAR)-α and various genes of the lipid metabolism in liver and adipose tissue of pigs. An experiment with 18 pigs was performed in which pigs were fed either a control diet or the same diet supplemented with 5 g clofibrate/kg for 28 days. Pigs treated with clofibrate had heavier livers, moderately increased mRNA concentrations of various PPAR-α target genes in liver and adipose tissue, a higher concentration of 3-hydroxybutyrate, and markedly lower concentrations of triglycerides and cholesterol in plasma and lipoproteins than control pigs ( P < 0.05). mRNA concentrations of sterol regulatory element-binding proteins (SREBP)-1 and -2, insulin-induced genes ( Insig) -1 and Insig-2, and the SREBP target genes acetyl-CoA carboxylase, 3-methyl-3-hydroxyglutaryl-CoA reductase, and low-density lipoprotein receptor in liver and adipose tissue and mRNA concentrations of apolipoproteins A-I, A-II, and C-III in the liver were not different between both groups of pigs. In conclusion, this study shows that clofibrate treatment activates PPAR-α in liver and adipose tissue and has a strong hypotriglyceridemic and hypocholesterolemic effect in pigs. The finding that mRNA concentrations of some proteins responsible for the hypolipidemic action of fibrates in humans were not altered suggests that there were certain differences in the mode of action compared with humans. It is also shown that PPAR-α activation by clofibrate does not affect hepatic expression of SREBP target genes involved in synthesis of triglycerides and cholesterol homeostasis in liver and adipose tissue of pigs.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Elisa Benetti ◽  
Raffaella Mastrocola ◽  
Mara Rogazzo ◽  
Fausto Chiazza ◽  
Manuela Aragno ◽  
...  

Peroxisome Proliferator Activated Receptor (PPAR)-δagonists may serve for treating metabolic diseases. However, the effects of PPAR-δagonism within the skeletal muscle, which plays a key role in whole-body glucose metabolism, remain unclear. This study aimed to investigate the signaling pathways activated in the gastrocnemius muscle by chronic administration of the selective PPAR-δagonist, GW0742 (1 mg/kg/day for 16 weeks), in male C57Bl6/J mice treated for 30 weeks with high-fructose corn syrup (HFCS), the major sweetener in foods and soft-drinks (15% wt/vol in drinking water). Mice fed with the HFCS diet exhibited hyperlipidemia, hyperinsulinemia, hyperleptinemia, and hypoadiponectinemia. In the gastrocnemius muscle, HFCS impaired insulin and AMP-activated protein kinase signaling pathways and reduced GLUT-4 and GLUT-5 expression and membrane translocation. GW0742 administration induced PPAR-δupregulation and improvement in glucose and lipid metabolism. Diet-induced activation of nuclear factor-κB and expression of inducible-nitric-oxide-synthase and intercellular-adhesion-molecule-1 were attenuated by drug treatment. These effects were accompanied by reduction in the serum concentration of interleukin-6 and increase in muscular expression of fibroblast growth factor-21. Overall, here we show that PPAR-δactivation protects the skeletal muscle against the metabolic abnormalities caused by chronic HFCS exposure by affecting multiple levels of the insulin and inflammatory cascades.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Pimonrat Ketsawatsomkron ◽  
Deborah R Davis ◽  
Aline M Hilzendeger ◽  
Justin L Grobe ◽  
Curt D Sigmund

PPARG, a ligand-activated transcription factor plays a critical role in the regulation of blood pressure and vascular function. We hypothesized that smooth muscle cell (SMC) PPARG protects against hypertension (HT) and resistance vessel dysfunction. Transgenic mice expressing dominant negative PPARG (S-P467L) in SMC or non-transgenic controls (NT) were implanted with DOCA pellet and allowed ad libitum access to 0.15 M NaCl for 21 days in addition to regular chow and water. Blood pressure was monitored by telemetry and mesenteric arterial (MA) function was assessed by pressurized myograph. At baseline, 24-hour mean arterial pressure (MAP) was similar between NT and S-P467L mice, while the transgenic mice were tachycardic. DOCA-salt increased MAP to a much greater degree in S-P467L mice (Δ MAP; S-P467L: +34.2±6.0, NT: +13.3±5.7, p<0.05 vs NT). Heart rate was similarly decreased in both groups after DOCA-salt. Vasoconstriction to KCl, phenylephrine and endothelin-1 did not differ in MA from DOCA-salt treated NT and S-P467L, while the response to vasopressin was significantly reduced in S-P467L after DOCA-salt (% constriction at 10-8 M, S-P467L: 31.6±5.6, NT: 46.7±3.8, p<0.05 vs NT). Urinary copeptin, a surrogate marker for arginine vasopressin was similar in both groups regardless of treatment. Vasorelaxation to acetylcholine was slightly impaired in S-P467L MA compared to NT at baseline whereas this effect was further exaggerated after DOCA-salt (% relaxation at 10-5 M, S-P467L: 56.1±8.3, NT: 79.4±5.6, p<0.05 vs NT). Vascular morphology at luminal pressure of 75 mmHg showed a significant increase in wall thickness (S-P467L: 18.7±0.8, NT: 16.0±0.4, p<0.05 vs NT) and % media/lumen (S-P467L: 8.4±0.3, NT: 7.1±0.2, p<0.05 vs NT) in S-P467L MA after DOCA-salt. Expression of tissue inhibitor of metalloproteinases (TIMP)-4 and regulator of G-protein signaling (RGS)-5 transcript were 2- and 3.5-fold increased, respectively, in MA of NT with DOCA-salt compared to NT baseline. However, this induction was markedly blunted in S-P467L MA. We conclude that interference with PPARG function in SMC leads to altered gene expression crucial for normal vascular homeostasis, thereby sensitizing the mice to the effects of DOCA-salt induced HT and vascular dysfunction.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Terry D Hinds ◽  
Nader G Abraham

The peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that is known to regulate glucose and lipid homeostasis and increases expression of the hormone fibroblast growth factor 21 (FGF21), which is secreted to blood, increases phosphorylation of AMPK and AKT in adipocytes and has been purported to stimulate adiponectin synthesis. The heme oxygenase (HO) system is functionally important for reducing ROS and inflammation whose induction has been shown to increase serum adiponectin levels and affect lowering of blood glucose and fatty acids. This study was designed to examine the hypothesis that a HO-1-PPARα crosstalk could elevate hepatic FGF21 thus leading to enhanced adiponectin secretion and abatement of metabolic imbalance. Preliminary experiments were conducted in human hepatocellular carcinoma cells (Hep G2) cultured in the absence or presence of the HO-1 inducer, cobalt protoporphyrin (CoPP, 2μmoles/l). A 2.0 fold induction of HO-1 in Hep G2 cells by CoPP (p<0.05) increased expression of FGF21 1.5 fold (n=3, p=0.0119 vs. vehicle control) without affecting PPARα expression. Additional experiments in obese (ob/ob) mice treated with CoPP (5mg/kg/day) resulted in 2 fold (p<0.05) increase of FGF21 mRNA expression in liver as compared to mice treated with the vehicle. These observations were complemented by blood glucose measurements, which showed significant attenuation in obese mice treated with CoPP (vehicle: 285.0±24 vs. CoPP: 160.0±27.3, p<0.05, n= 5), along with enhancement of adiponectin levels in CoPP treated obese mice (p<0.05). Taken together these results demonstrate that HO-1 could increase serum adiponectin levels and insulin sensitivity by elevating hepatic FGF21 levels. Our overall hypothesis is that the HO-1 can stimulate PPARα activity with resultant activation of hepatic FGF21 secretion and that this HO-PPARα-FGF21 axis could work in concert to modulate the development of insulin resistance and diabetes.


PPAR Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Sakil Kulkarni ◽  
Jiansheng Huang ◽  
Eric Tycksen ◽  
Paul F. Cliften ◽  
David A. Rudnick

Pioglitazone (Pio) is a thiazolidinedione (TZD) insulin-sensitizing drug whose effects result predominantly from its modulation of the transcriptional activity of peroxisome proliferator-activated-receptor-gamma (PPARγ). Pio is used to treat human insulin-resistant diabetes and also frequently considered for treatment of nonalcoholic steatohepatitis (NASH). In both settings, Pio’s beneficial effects are believed to result primarily from its actions on adipose PPARγ activity, which improves insulin sensitivity and reduces the delivery of fatty acids to the liver. Nevertheless, a recent clinical trial showed variable efficacy of Pio in human NASH. Hepatocytes also express PPARγ, and such expression increases with insulin resistance and in nonalcoholic fatty liver disease (NAFLD). Furthermore, mice that overexpress hepatocellular PPARγ and Pio-treated mice with extrahepatic PPARγ gene disruption develop features of NAFLD. Thus, Pio’s direct impact on hepatocellular gene expression might also be a determinant of this drug’s ultimate influence on insulin resistance and NAFLD. Previous studies have characterized Pio’s PPARγ-dependent effects on hepatic expression of specific adipogenic, lipogenic, and other metabolic genes. However, such transcriptional regulation has not been comprehensively assessed. The studies reported here address that consideration by genome-wide comparisons of Pio’s hepatic transcriptional effects in wildtype (WT) and liver-specific PPARγ-knockout (KO) mice given either control or high-fat (HFD) diets. The results identify a large set of hepatic genes for which Pio’s liver PPARγ-dependent transcriptional effects are concordant with its effects on RXR-DNA binding in WT mice. These data also show that HFD modifies Pio’s influence on a subset of such transcriptional regulation. Finally, our findings reveal a broader influence of Pio on PPARγ-dependent hepatic expression of nuclear genes encoding mitochondrial proteins than previously recognized. Taken together, these studies provide new insights about the tissue-specific mechanisms by which Pio affects hepatic gene expression and the broad scope of this drug’s influence on such regulation.


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