Fibroblast Growth Factor mRNA Research Articles

Function of fibroblast growth factor 2 in gastric cancer occurrence and prognosis.

The present study aimed to explore the role of fibroblast growth factor 2 (FGF2) in the development and prognosis of gastric cancer (GC). The relationship between FGF2 mRNA expression levels and the clinical characteristics of GC was investigated using microarray data from four GC cohorts involving 726 patients obtained from the Gene Expression Omnibus. The results of the present study indicated that FGF2 expression levels were an independent factor affecting the prognosis of GC. The primary functions of FGF2 were related to cell adhesion and angiogenesis, and patients with high levels of FGF2 expression had poorer TNM staging and prognosis; these differences were statistically significant. In terms of immune infiltration, a higher extent of M2 macrophage intrusion was observed in patients with higher levels of FGF2. However, the degree of infiltration by dendritic and CD4+ T cells was lower, and this difference was statistically significant. Multivariate Cox proportional hazards model analysis revealed that age, TNM staging and FGF2 expression levels were independent prognostic factors for GC. In summary, FGF2 expression was demonstrated to be an independent prognostic factor in GC, and higher levels of FGF2 may promote the progression of this malignancy.

Downregulation of Linc-RNA activator of myogenesis lncRNA participates in FGF2-mediated proliferation of human periodontal ligament stem cells.

Accelerated proliferation of human periodontal ligament stem cells (PDLSCs) is present in periodontitis. It is known that fibroblast growth factor 2 (FGF2) regulates the proliferation of PDLSCs, while the function of FGF2 in myogenic cell differentiation is mediated by Linc-RNA Activator of Myogenesis (Linc-RAM) lncRNA. Therefore, Linc-RAM lncRNA may also participate in periodontitis. This study included 28 patients with periodontitis (patient group) and 22 patients without periodontitis but received orthodontic treatment (control group) in the stomatological hospital of Sun Yat-Sen university. Gingival biopsies were obtained from participants. RT-qPCR, cell transfection, cell proliferation assay and western blot were carrying out to analyze the samples. We found that FGF2 mRNA was upregulated, while Linc-RAM was downregulated in PDLSCs derived from periodontitis-affected teeth than in healthy teeth. FGF2 mRNA and Linc-RAM were inversely correlated in both types of PDLSCs. FGF2 overexpression led to inhibited Linc-RAM expression in PDLSCs derived from periodontitis-affected teeth and promoted the proliferation of PDLSCs. Linc-RAM overexpression failed to significantly affect FGF2 expression but attenuated the enhancing effects of FGF2 overexpression on the proliferation of PDLSCs. Therefore, downregulation of Linc-RAM lncRNA may participate in FGF-2 mediated- proliferation of human PDLSCs.

Klotho-beta and fibroblast growth factor 19 expression correlates with early recurrence of resectable hepatocellular carcinoma.

Fibroblast growth factor 19 (FGF19) and fibroblast growth factor receptor 4 (FGFR4) signalling play critical roles in hepatocarcinogenesis. This study explored the potential of FGF19- and FGFR4-related biomarkers in predicting early tumour recurrence (ETR) and survival in patients with resectable hepatocellular carcinoma (HCC). We examined the mRNA expressions of FGF19, FGFR4, klotho-beta (KLB), cyclin D1 (CCND1) and FGF4 in 151 surgically resected, primary unifocal HCCs through quantitative real-time polymerase chain reaction. Generalized additive models were fitted to detect nonlinear effects of continuous covariates and define thresholds of biomarker expressions. Univariate and multivariate analyses were performed to evaluate prognostic values of these biomarkers for tumour recurrence and patient survival. Overexpression of FGF19, FGFR4, KLB, CCND1 and FGF4 mRNA was detected in 40%, 32%, 26%, 15% and 35% of 151 tumours respectively. ETR was the strongest prognostic factor predicting worse overall survival (hazard ratio [HR], 5.678; 95% confidence interval, 3.7-8.713; P<0.001). Furthermore, we revealed that mRNA expression levels of KLB (HR, 3.857; P=0.021) and FGF19 (HR, 3.248; P=0.017) were significantly associated with the occurrence of ETR. Frequent overexpression of FGF19/FGFR4-related biomarkers was detected in resectable HCC. Expression levels of KLB and FGF19 may determine patient survival outcomes through their effects on ETR.

MALAT1 overexpression promotes the proliferation of human periodontal ligament stem cells by upregulating fibroblast growth factor 2.

Fibroblast growth factor 2 (FGF2) has been revealed to promote human periodontal ligament stem cell (PDLSC) proliferation. The abnormal proliferation of PDLSCs has also been associated with the pathogenesis of periodontitis. The long non-coding RNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), has been demonstrated to regulate FGF2 secretion. Therefore, MALAT1 may also be associated with periodontitis. The aim of the present study was to investigate the effect of MALAT1 overexpression on the proliferation of PDLSCs. In the current study, PDLSCs derived from healthy and periodontitis-affected teeth were collected. MALAT1 and FGF2 mRNA expression in PDLSCs was detected using reverse transcription-quantitative PCR. PDLSCs overexpressing MALAT1 were subsequently generated. PDLSC proliferation was analyzed using a Cell Counting kit-8 assay. FGF2 protein expression was detected using western blot analysis. The results revealed that MALAT1 and FGF2 mRNA were significantly upregulated in PDLSCs derived from periodontitis-affected teeth when compared with PDLSCs derived from healthy teeth. PDLSCs derived from periodontitis-affected teeth also demonstrated a significantly higher proliferation rate than PDLSCs derived from healthy teeth. MALAT1 and FGF2 mRNA expression were positively correlated in both PDLSC groups. MALAT1 overexpression promoted the proliferation of healthy and periodontitis-affected PDLSC groups and upregulated FGF2 protein expression. The present study concluded that MALAT1 overexpression promoted the proliferation of human PDLSC potentially via upregulating FGF2.

Potential biomarker of fibroblast growth factor 21 in valproic acid-treated livers.

Valproic acid (VPA) is a clinical medicine primarily prescribed to control epileptic symptoms. VPA has potential side-effects, such as hepatotoxicity. Fibroblast growth factor 21 (FGF21) is a functional cytokine for metabolic regulation. In this article, we aimed to evaluate the possible clinical application of FGF21 in VPA-treated livers in early undetected liver injury (EULI). Methodologically, plasma samples of VPA-treated epileptic patients were isolated for biochemical and high-performance liquid chromatography tests. In addition, VPA-dosed mice were subjected to determinations of serological parameters, key regulatory effectors and FGF21 expressions through biochemical analyses, enzyme-linked immunosorbent assay, immunohistochemistry stain, immunofluorescence stain, and reverse transcription-polymerase chain reaction (RT-PCR) test, respectively. The serological data suggested that VPA-treated epileptic patients showed visibly elevated FGF21 contents in plasma samples. However, other diagnostic parameters showed inconspicuous changes. As revealed in animal study, VPA-dosed mice exhibited undetected morphological alterations and hormonal changes in the liver, pancreas, and kidneys. Furthermore, serological parameters and key regulatory proteins in VPA-dosed livers and controls showed inconspicuous changes. Interestingly, endogenous FGF21 expressions in VPA-dosed mice were increased in sera. In further experiments, the findings showed that intracellular expressions of FGF21 mRNA and protein were upregulated in VPA-dosed livers as revealed in RT-PCR and immunoassay. Taken together, these preliminary data reveal that functional FGF21 cytokine may serve as a potent predictor in VPA-related EULI.

MS-275 induces hepatic FGF21 expression via H3K18ac-mediated CREBH signal.

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.

Translational Control of FGF21 mRNA Expression is Responsive to Nutritional Stress

Fibroblast growth factor 21 (FGF21) is a peptide hormone associated with the pathogenesis of several metabolic disorders such as Non‐alcoholic Fatty Liver Disease (NAFLD), Type‐2‐Diabetes, and obesity. Notably, FGF21 treatment is associated with enhanced insulin sensitivity, and in rodents, attenuation of the metabolic defects associated with consumption of a high‐fat diet. Because the majority of circulating FGF21 is secreted by the liver in mammals, understanding the mechanisms that regulate hepatic expression of the hormone is critical. Hepatic FGF21 expression has been shown to be regulated in part through changes in FGF21 gene transcription. However, recent studies have shown transcription‐independent changes in FGF21 secretion from isolated hepatocytes, implying that FGF21 protein expression is also regulated at the level of mRNA translation. Thus, the goal of the present study was to assess whether or not the FGF21 mRNA is translationally regulated using H4IIE hepatoma cells as a model system. In these studies, cells were treated with rapamycin as a mimic of starvation and translation of the FGF21 mRNA was assessed using sucrose density gradient centrifugation to separate mRNAs that are poorly translated, i.e. mRNAs associated with 3 or fewer ribosomes (“light” polysomes) from well‐translated mRNAs, i.e. mRNAs associated with four or more ribosomes (“heavy” polysomes). As a positive control, mRNAs bearing a terminal oligopyrimidine tract (TOP) at the 5′‐end of the message were also assessed, as previous studies have shown them to be translationally downregulated under the conditions used in this study. As expected rapamycin treatment resulted in repressed translation of the TOP mRNAs, as demonstrated by a shift of the mRNAs from heavy to light polysomes. In contrast, translation of the FGF21 mRNA was enhanced by rapamycin, suggesting that it is regulated through an mTORC1‐dependent mechanism distinct from, and opposite to, mRNAs with a TOP motif. Current efforts are directed toward identifying the regulatory element(s) in the FGF21 mRNA that engenders sensitivity to rapamycin‐induced translational upregulation.Support or Funding Information(Supported by NIH grant DK13499)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Intestinal serine protease inhibition increases FGF21 and improves metabolism in obese mice.

Trypsin is the major serine protease responsible for intestinal protein digestion. An inhibitor, camostat (CS), reduced weight gain, hyperglycemia, and dyslipidemia in obese rats; however, the mechanisms for these are largely unknown. We reasoned that CS creates an apparent dietary protein restriction, which is known to increase hepatic fibroblast growth factor 21 (FGF21). Therefore, metabolic responses to CS and a gut-restricted CS metabolite, FOY-251, were measured in mice. Food intake, body weight, blood glucose, branched-chain amino acids (LC/MS), hormone levels (ELISA), liver pathology (histology), and transcriptional changes (qRT-PCR) were measured in ob/ob, lean and diet-induced obese (DIO) C57BL/6 mice. In ob/ob mice, CS in chow (9-69 mg/kg) or FOY-251 (46 mg/kg) reduced food intake and body weight gain to a similar extent as pair-fed mice. CS decreased blood glucose, liver weight, and lipidosis and increased FGF21 gene transcription and plasma levels. In lean mice, CS increased liver FGF21 mRNA and plasma levels. Relative to pair feeding, FOY-251 also increased plasma FGF21 and induced liver FGF21 and integrated stress response (ISR) transcription. In DIO mice, FOY-251 (100 mg/kg po) did not alter peak glucose levels but reduced the AUC of the glucose excursion in response to an oral glucose challenge. FOY-251 increased plasma FGF21 levels. In addition to previously reported satiety-dependent (cholecystokinin-mediated) actions, intestinal trypsin inhibition engages non-satiety-related pathways in both leptin-deficient and DIO mice. This novel mechanism improves metabolism by a liver-integrated stress response and increased FGF21 expression levels in mice. NEW & NOTEWORTHY Trypsin inhibitors, including plant-based consumer products, have long been associated with metabolic improvements. Studies in the 1980s and 1990s suggested this was due to satiety hormones and caloric wasting by loss of protein and fatty acids in feces. This work suggests an entirely new mechanism based on the lower amounts of digested protein available in the gut. This apparent protein reduction may cause beneficial metabolic adaptation by the intestinal-liver axis to perceived nutrient stress.

Impact of aging and caloric restriction on fibroblast growth factor 21 signaling in rat white adipose tissue

Caloric restriction (CR) suppresses age-related pathophysiology and extends lifespan. We recently reported that metabolic remodeling of white adipose tissue (WAT) plays an important role in the beneficial actions of CR; however, the detailed molecular mechanisms of this remodeling remain to be established. In the present study, we aimed to identify CR-induced alterations in the expression of fibroblast growth factor 21 (FGF21), a regulator of lipid and glucose metabolism, and of its downstream signaling mediators in liver and WAT, across the lifespan of rats. We evaluated groups of rats that had been either fed ad libitum or calorie restricted from 3 months of age and were euthanized at 3.5, 9, or 24 months of age, under fed and fasted conditions. The expression of FGF21 mRNA and/or protein increased with age in liver and WAT. Interestingly, in the WAT of 9-month-old fed rats, CR further upregulated FGF21 expression and eliminated the aging-associated reductions in the expression of FGFR1 and beta-klotho (KLB; FGF21 receptor complex). It also enhanced the expression of FGF21 targets, including glucose transporter 1 and peroxisome proliferator-activated receptor (PPAR)γ coactivator-1α. The analysis of transcriptional regulators of Fgf21 suggested that aging and CR might upregulate Fgf21 expression via different mechanisms. In adipocytes in vitro, constitutive FGF21 overexpression upregulated the FGF21 receptor complex and FGF21 targets at the mRNA or protein level. Thus, both aging and CR induced FGF21 expression in rat WAT; however, only CR activated FGF21 signaling. Our results suggest that FGF21 signaling contributes to the CR-induced metabolic remodeling of WAT, likely activating glucose uptake and mitochondrial biogenesis.

Fibroblast growth factor 21, adiposity, and macronutrient balance in a healthy, pregnant population with overweight and obesity

ABSTRACTAim of the study: The regulation and actions of fibroblast growth factor 21 (FGF21) are responsive to energy status and macronutrient balance, and investigations of FGF21 in normal pregnancy, which could be informative for FGF21 biology, are seldom. The goal of our study was to examine FGF21 levels in a contemporary healthy, pregnant population.Methods: We phenotyped 43 women with overweight and obesity during pregnancy for weight, body composition, and fasting blood. Serum FGF21 was measured during the first and third trimesters. Placentas were collected at delivery.Results: Maternal FGF21 concentrations were positively correlated with body mass index and adiposity, but not lean mass or glucose homeostasis. FGF21 concentrations significantly increased from the first to third trimester of pregnancy (0.105 vs. 0.256 ng/mL, p < 0.0001). Changes in FGF21 concentrations across pregnancy were not associated with changes in body weight or composition but inversely with the change in fasting glucose. FGF21 mRNA levels in placenta were very low and do not likely contribute to FGF21 in the maternal circulation.Conclusions: FGF21 increases throughout pregnancy in our healthy cohort with overweight and obesity, independent of the placenta, and does not appear to be sensing the changes in energy balance (reflected in the change in maternal energy stores), but changes in macronutrient status. Thus, we propose FGF21 may be a potential signal of maternal nutrient status in pregnancy.

HDAC3 inhibition in diabetic mice may activate Nrf2 preventing diabetes-induced liver damage and FGF21 synthesis and secretion leading to aortic protection.

Vascular complications are common pathologies associated with type 1 diabetes. In recent years, histone deacetylation enzyme (HDAC) inhibitors have been shown to be successful in preventing atherosclerosis. To investigate the mechanism for HDAC3 inhibition in preventing diabetic aortic pathologies, male OVE26 type 1 diabetic mice and age-matched wild-type (FVB) mice were given the HDAC3-specific inhibitor RGFP-966 or vehicle for 3 mo. These mice were then euthanized immediately or maintained for an additional 3 mo without treatment. Levels of aortic inflammation and fibrosis and plasma and fibroblast growth factor 21 (FGF21) levels were determined. Because the liver is the major organ for FGF21 synthesis in diabetic animals, the effects of HDAC3 inhibition on hepatic FGF21 synthesis were examined. Additionally, hepatic miR-200a and kelch-like ECH-associated protein 1 (Keap1) expression and nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation were measured. HDAC3 inhibition significantly reduced aortic fibrosis and inflammation in OVE26 mice at both 3 and 6 mo. Plasma FGF21 levels were significantly higher in RGFP-966-treated OVE26 mice compared with vehicle-treated mice at both time points. It also significantly reduced hepatic pathologies associated with diabetes, accompanied by increased FGF21 mRNA and protein expression. HDAC3 inhibition also increased miR-200a expression, reduced Keap1 protein levels, and increased Nrf2 nuclear translocation with an upregulation of antioxidant gene and FGF21 transcription. Our results support a model where HDAC3 inhibition may promote Nrf2 activity by increasing miR-200a expression with a concomitant decrease in Keap1 to preserve hepatic FGF21 synthesis. The preservation of hepatic FGF21 synthesis ultimately leads to a reduction in diabetes-induced aorta pathologies.

Effect of EPO on PRDM16, FGF21 expression and STAT phosphorylation of brown adipose tissue in HFD mice

To investigate the effect of erythropoietin (EPO) on blood glucoseand plasma insulin level, index of insulin resistance (HOMA-IR), introperitoneal glucose tolerance test (IPGTT), the mRNA and protein level of PR domain-containing 16 (PRDM16), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), fibroblast growth factor 21 (FGF21) of brown adipose tissue (BAT) in mice fed with high fat diet (HFD) in order to provide clues for the mechanism of obesity and complication. Twenty C57BL/6J male mice fed with HFD were randomly divided into control group (HFD-Con) and EPO group (HFD-EPO), mice in the two groups were injected intraperitoneally normal saline and EPO (200 IU/kg) res pectively, 3 times per week for consecutive 4 weeks.Then the body weight, blood glucose, plasma insulin level, HOMA-IR and IPGTT were detected.The mRNA and protein level of PRDM16, FGF21, p-STAT3/STAT3 in brown adipose tissue were detected by real-time quantitative RT-PCR and Western blot respectively. After intraperitoneal injection of EPO for 4 weeks, the body weight of the mice in HFD-EPO and HFD-Con groups was (26.65±0.85) g and (31.50±1.6 0) g respectively.The blood glucose of the mice in HFD-EPO group[(62.79±8.09) mg/dl]was significantly decreased compared with that in HFD-Con group[(91.06±9.86) mg/dl].The plasmainsulin level in HFD-EPO group[(10.56±1.06)μU/ml]was significantly decreased compared with that in HFD-Con group[(13.2±1.1)μU/ml, P< 0.01].The level of IPGTT in HFD-EPO group was significantly ameliorated and th e HOMA-IR decreased compared with those in HFD-Con group.The mRNA and protein expressions of PRDM16, FGF21 and the level of STAT3 of brown adipose tissue in HFD-E PO group were increased obviously.And there was no difference of FGF21 mRNA content in liver and FGF21 content in plasmabetween the two groups. EPO could promote differentiation of brown adipose tissue by increase in the express ion of PRDM16, and decrease the blood glucose level, ameliorate glucose metabolism in obses mice.

Effects of non‐esterified fatty acids on the expression and secretion of angiopoietin‐like protein 4 and fibroblast growth factor 21 in calf hepatocytes cultured in vitro

IntroductionNegative energy balance (NEB) is considered as the pathological basis of energy metabolic disorders, such as fatty liver and ketosis, in periparturient dairy cows. An elevated serum non‐esterified fatty acids (NEFA) concentration is one of the most important indicators of NEB. Angiopoietin‐like protein 4 (ANGPTL4) and fibroblast growth factor 21 (FGF21) have been identified as hepatokines, which involved in regulation of metabolic adaptations. In dairy cows, most circulating ANGPTL4 and FGF21 originate from the liver. However, the direct effects of NEFA on the expression and secretion of ANGPTL4 and FGF21 in bovine hepatocytes are not entirely clear. The purpose of the present study was to investigate the effects of different NEFA concentrations on the expression and secretion of these two hepatokines in calf hepatocytes cultured in vitro.MethodsBovine hepatocytes were cultured using the collagenase perfusion method. After culture for 72 h, the hepatocytes were treated with NEFA at final concentrations of 0 (control), 0.6, 1.2, 1.8 and 2.4 mmol/L. After 24 h of continuous culture, the mRNA and protein expression levels of ANGPTL4 and FGF21 in the hepatocytes were determined by real‐time PCR and Western blot, respectively. ANGPTL4 and FGF21 secretions in the supernatant were determined by enzyme‐linked immunosorbent assay (ELISA).ResultsThe results showed similar levels of ANGPTL4 expression and secretion following treatment with 0.6 and 1.2 mmol/L NEFA, which were higher than those observed for the controls (P&lt;0.05). ANGPTL4 expression and secretion were also similar at 1.8 and 2.4 mmol/L NEFA and significantly higher than those observed for controls (P&lt;0.01). The expression and secretion of FGF21 at 0.6 mmol/L NEFA‐treated hepatocytes was higher than that of the control group (P&lt;0.05). The FGF21 expression and secretion were similar at 1.2, 1.8 and 2.4 mmol/L NEFA‐treated hepatocytes and significantly higher than those observed for controls (P&lt;0.01).ConclusionThe results of this study indicate that high concentrations of NEFA significantly increase the expression and secretion of ANGPTL4 and FGF21 in bovine hepatocytes cultured in vitro in a dose‐dependent manner. Specifically, NEFA promotes the expression and secretion of ANGPTL4 and FGF21, which may worsen fat mobilization under NEB conditions and thereby lead to the pathological processes of energy metabolism disorders in dairy cows in the peripartum period. However, further studies are needed to elucidate the underlying mechanisms.Support or Funding InformationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Purinergic Signaling Controls Fibroblast Growth Factor‐21 Expression in Skeletal Muscle through Akt/mTOR Pathway.

Fibroblast Growth Factor‐21 (FGF‐21) is a myokine which induce fiber type transformation and metabolic adaptations in muscle. However, little is known about the molecular mechanisms involved in the regulation of FGF‐21 expression in skeletal muscle in non‐pathological conditions. We have previously described that purinergic signaling is related with muscle adaptations and IL6‐myokine production through the “excitation‐transcription coupling” (ETC) mechanism, in which extracellular ATP (eATP) promotes gene expression in skeletal muscle. We have also demonstrated that eATP activates the PI3K/Akt signaling pathway in myotubes. Considering that Akt has been proposed as a master regulator for FGF‐21 expression control, the aim of this work is to determine the role of extracellular ATP over the FGF‐21 production in adult mouse skeletal muscle, and their dependence on the Akt/mTOR signaling pathway. Mice FDB‐isolated fibers or whole‐muscle were used in this study. The mRNA levels of FGF‐21 after electrical (20 Hz, 270 pulses, 0.3 msec each) or exogenous ATP (100 μM) stimulation were assessed by qPCR. FGF‐21 protein levels were assessed by immunoblot. We used pharmacological inhibitors of purinergic receptors (100 μM Suramin) and Akt/mTOR pathway inhibitors (50 μM LY294002; 1 μM Akt inhibitor VIII; 100 nM rapamycin), to turn off different interactors of the putative signaling pathway. ATP stimulation (100 μM) evoked an 8‐fold increase in FGF‐21 mRNA levels in isolated FDB fibers at 30 min post stimulation. The increase in FGF‐21 mRNA levels evoked by eATP was inhibited by suramin, a general antagonist of P2Y/P2X nucleotide receptors. Electrical stimulation also evokes an increase in FGF‐21 mRNA levels, which was inhibited by both nifedipine (a DHPR blocker) and suramin. Exogenous ATP increased protein levels of FGF‐21 in whole FDB‐muscles at 120 min, in a concentration‐dependent manner, with a maximal increase of 3.5 folds with 3 μM ATP. The increase in FGF‐21 protein level evoked by ATP, was abolished by LY294002 (a PI3K inhibitor), Akt inhibitor VIII, and rapamycin (mTOR inhibitor). In this work, we demonstrated for the first time that extracellular ATP evokes an increase in the mRNA and protein levels of FGF‐21 in skeletal muscle. The increase on FGF‐21 levels evoked by ATP is dependent on Akt/mTOR pathway activation. These results suggest that ETC mechanism could be involved in regulation of FGF‐21 expression in skeletal muscle.Support or Funding InformationFunded by CONICYT PCHA 21151035(MA‐C), 63140009(CM) and Fondecyt 1151353(SB), 1151293(EJ)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Expression level of fibroblast growth factor 5 (FGF5) in the peripheral blood of primary hypertension and its clinical significance.

ObjectiveTo explore the expression level of FGF5 in the peripheral blood of primary hypertension patients and its clinical significance.MethodsThe 34 patients with primary hypertension treated in this hospital from June 2012 to June 2014 were selected as the observation group, while the 25 patients at this hospital who had physical exam with heathy results were selected as control group. Venous blood was drawn early in the morning after an overnight fast. FGF5, mRNA and protein level changes in the peripheral blood cells and peripheral blood serum were analyzed by real-time fluorescence based quantitative PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). FGF5 gene SNP (rs16998073) were amplified by PCR and inserted into T vector, and its genetic variation were analyzed by sequencing. The relationship of FGF5 protein levels and genetic variation with diastolic/systolic blood pressure was also analyzed.ResultsComparing with the control group, the observation group’s FGF5 mRNA and protein levels significantly increased in the peripheral blood cells and peripheral blood. The difference was statistically significant (P < .05). Correlation analysis showed that FGF5 protein level and systolic/diastolic blood pressure were positively correlated (P < .05). T/A genetic variation of FGF5 gene SNP (rs16998073) and diastolic/systolic blood pressure were positively correlated (P < .05).ConclusionThe FGF5 mRNA and protein expression levels of the patients with primary hypertension were abnormal and had genetic variation, which were associated with blood pressure of the patients with primary hypertension.

Therapeutic effects of fibroblast growth factor‑21 against atherosclerosis via the NF‑κB pathway.

Fibroblast growth factor-21 (FGF-21) is a pleiotropic protein predominantly secreted in the liver, adipose tissue and pancreas. It has been reported that the metabolic hormone effects of FGF-21 on energy metabolism are essential for human vascular endothelial cells. The aim of the present study was to investigate the therapeutic effects and the underlying primary mechanism of FGF-21 on atherosclerosis in a rat model induced by vitamin D3 and a high fat diet. The rats with atherosclerosis were randomly divided into vehicle (PBS; negative control), FGF-21 (6 mg/kg/d) and atorvastatin (6 mg/kg/d; positive control) groups (n=40 in each group). The rats with atherosclerosis received continuous drug or PBS administration via intravenous injection for a treatment period of 30 days, following which all animals were sacrificed. The expression levels of FGF-21 were determined prior to and following treatment with the drug or PBS. Alterations in ultrastructure and histopathology in vascular endothelial cells were examined, and the expression of nuclear transcription factor kappa B (NF-κB) and levels of blood lipids in the thoracic aorta tissues were also determined. The results showed that typical atheromatous plaques formed, and the mRNA and protein expression levels of FGF-21 were lower in the vascular endothelial cells of the rats with atherosclerosis, compared with the normal rats. FGF-21 significantly reduced blood lipids and glucose in the rats with atherosclerosis, compared with those in the PBS and atorvastatin groups (P<0.01). The expression levels of Rho kinase and NF-κB were significantly lower in the FGF-21 group, compared with the normal control group (P<0.01). Statistically significant differences were found in atheromatous plaques and inflammatory factors in the FGF-21 group, compared with the PBS and atorvastatin groups (P<0.01). In conclusion, FGF-21 significantly downregulated the levels of blood lipids, Rho kinase and NF-κB, which contributed to atherosclerosis therapy in the model rats and indicated the potential mechanisms against atherosclerosis in the model rats.

Effect of circulating glucagon and free fatty acids on hepatic FGF21 production in dairy cows.

Modern dairy cows meet the energy demand of early lactation by calling on hormonally driven mechanisms to increase the use of lipid reserves. In this context, we recently reported that fibroblast growth factor-21 (FGF21), a hormone required for efficient use of lipid reserves in rodents, is upregulated in periparturient dairy cows. Increased plasma FGF21 in early lactation coincides with elevated circulating concentrations of glucagon (GCG) and nonesterified fatty acids (NEFA). To assess the relative contribution of these factors in regulating FGF21, two experiments were performed in energy-sufficient, nonpregnant, nonlactating dairy cows. In the first study, cows were injected with saline or GCG every 8 h over a 72-h period. GCG increased hepatic FGF21 mRNA by an average of fivefold over matched controls but had no effect on plasma FGF21. In the second study, cows were infused and injected with saline, infused with Intralipid and injected with saline, or infused with Intralipid and injected with GCG. Infusions and injections were administered intravenously over 16 h and subcutaneously every 8 h, respectively. Intralipid infusion increased plasma NEFA from 92 to 550 µM within 3 h and increased plasma FGF21 from 1.3 to >11 ng/ml 6 h later; FGF21 mRNA increased by 34-fold in liver but remained invariant in adipose tissue. GCG injections during the Intralipid infusion had no additional effects on plasma NEFA, liver FGF21 mRNA, or plasma FGF21. These data implicate plasma NEFA as a key factor triggering hepatic production and increased circulating concentrations of FGF21 in early lactation.

Lowered fasting chenodeoxycholic acid correlated with the decrease of fibroblast growth factor 19 in Chinese subjects with impaired fasting glucose

The gut-derived hormone Fibroblast growth factor 19 (FGF19) could regulate glucose metabolism and is induced by bile acids (BAs) through activating Farnesoid X Receptor (FXR). FGF19 was found to decrease in subjects with isolated-impaired fasting glucose (I-IFG) and type 2 diabetes mellitus (T2DM). However, the reason for the change of FGF19 in subjects with different glucometabolic status remained unclear. Here we measured six BAs including chenodeoxycholic acid (CDCA), cholic acid, deoxycholic acid, their glycine conjugates and FGF19 levels during oral glucose tolerance test (OGTT) in normal glucose tolerance (NGT), isolated-impaired glucose tolerance, I-IFG, combined glucose intolerance (CGI) and T2DM subjects. After OGTT, serum FGF19 peaked at 120 min in all subjects. Glycine conjugated BAs peaked at 30 min, while free BAs did not elevated significantly. Consistent with the decrease trend in FGF19 levels, fasting serum CDCA levels in subjects with I-IFG, CGI and T2DM were significantly lower than NGT subjects (P < 0.05). Fasting serum CDCA was independently associated with FGF19. CDCA strongly upregulated FGF19 mRNA levels in LS174T cells in a dose- and time-dependent manner. These results suggest that the decrease of FGF19 in subjects with I-IFG was at least partially due to their decrease of CDCA acting via FXR.

Cigarette Smoking Affects Uterine Receptivity Markers.

Smoking negatively affects fertility and the rate of other endometrial diseases. To determine the effect of smoking on endometrial physiology, we evaluated 2 endometrial regulatory cytokines and receptivity markers, C-X-C motif chemokine ligand 12 (CXCL12) and fibroblast growth factor 2 (FGF2), both in vitro and in vivo. The human endometrial stromal cell line (HESC) and primary human endometrial stromal cells were treated with cigarette smoking extract (CSE) or with vehicle control. Twenty female mice were randomly assigned to either cigarette smoke (CS) exposure for 8 weeks or to a nonsmoke (NS) group that received room air. Immunohistochemical analysis of CXCL12 and FGF2 expression was performed in mouse uterine tissue. Human endometrial samples were obtained from both nonsmokers and smokers. Real-time reverse transcription-polymerase chain reaction was performed for all cell cultures and human samples. Compared to controls, CXCL12 and FGF2 mRNA expression were significantly decreased in CSE-exposed HESC and primary cells. In mice, immunohistochemical analysis showed that both CXCL12 and FGF2 protein expression was lower in the CS group compared to controls. Similarly, both CXCL12 and FGF2 expression were decreased in women who smoke compared to nonsmokers. Decreased endometrial CXCL12 and FGF2 expression contribute to the impaired endometrial receptivity in women who smoke. Smoking is also associated with decreased rates of endometrial cancer and endometriosis; increased CXCL12 and FGF2 are implicated in both conditions. The changes in the expression of cytokines described here may explain the impact of smoking on all of these diseases. Tobacco has direct effects on normal endometrium that impacts endometrial health and disease.

Beta-adrenergic receptors are critical for weight loss but not for other metabolic adaptations to the consumption of a ketogenic diet in male mice

ObjectiveWe have previously shown that the consumption of a low-carbohydrate ketogenic diet (KD) by mice leads to a distinct physiologic state associated with weight loss, increased metabolic rate, and improved insulin sensitivity [1]. Furthermore, we identified fibroblast growth factor 21 (FGF21) as a necessary mediator of the changes, as mice lacking FGF21 fed KD gain rather than lose weight [2]. FGF21 activates the sympathetic nervous system (SNS) [3], which is a key regulator of metabolic rate. Thus, we considered that the SNS may play a role in mediating the metabolic adaption to ketosis. MethodsTo test this hypothesis, we measured the response of mice lacking all three β-adrenergic receptors (β-less mice) to KD feeding. ResultsIn contrast to wild-type (WT) controls, β-less mice gained weight, increased adipose tissue depots mass, and did not increase energy expenditure when consuming KD. Remarkably, despite weight-gain, β-less mice were insulin sensitive. KD-induced changes in hepatic gene expression of β-less mice were similar to those seen in WT controls eating KD. Expression of FGF21 mRNA rose over 60-fold in both WT and β-less mice fed KD, and corresponding circulating FGF21 levels were 12.5 ng/ml in KD-fed wild type controls and 35.5 ng/ml in KD-fed β-less mice. ConclusionsThe response of β-less mice distinguishes at least two distinct categories of physiologic effects in mice consuming KD. In the liver, KD regulates peroxisome proliferator-activated receptor alpha (PPARα)-dependent pathways through an action of FGF21 independent of the SNS and beta-adrenergic receptors. In sharp contrast, induction of interscapular brown adipose tissue (BAT) and increased energy expenditure absolutely require SNS signals involving action on one or more β-adrenergic receptors. In this way, the key metabolic actions of FGF21 in response to KD have diverse effector mechanisms.