<em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is a novel hormone-like polypeptide that when administered exogenously, has been shown to have beneficial effects on food intake, body weight, and metabolism. The in vivo mechanisms of action for its positive metabolic effects remain to be fully elucidated. It has been shown that PEGylation of human FGF<em>21</em> at specific and preferred sites confer superior metabolic pharmacology. We therefore hypothesized that low doses of PEGylated (30K PEG on position Q108) FGF<em>21</em> (PEG30-Q108) would improve insulin action, independent of any effect on food intake or body weight. We identified a dose (0.25mg/kg) that had no effect on food intake or body weight, yet did show beneficial metabolic effects. Four groups of 12 weeks, high-fat fed, insulin resistant mice were studied: mice dosed subcutaneously once with vehicle or 0.25mg/kg of PEG30-Q108 24h before the experiment, or mice dosed 4 times over 2 weeks with vehicle or PEG30-Q108. Conscious, unrestrained mice were fasted for 5h and underwent a hyperinsulinemic-euglycemic clamp. Both PEG30-Q108 treatments significantly lowered fasting insulin compared to vehicle, with no difference in food intake or body weight. Insulin-stimulated whole body glucose utilization was normalized to that of lean mice with both PEG30-Q108 treatments compared to vehicle. This accounted for all of the enhanced insulin action, as there was no improvement in insulin's ability to suppress endogenous glucose production. In line with these findings, neither PEG30-Q108 treatment lowered hepatic triglycerides. These results demonstrate the profound ability of PEG30-Q108 to increase whole body insulin sensitivity.

OBJECTIVE

Newborns with congenital diaphragmatic hernia (CDH) still have a high mortality rate, which has been attributed to pulmonary hypoplasia and pulmonary hypertension. Fibroblast growth factors (FGFs) are essential components of the gene network that regulates lung development. Recent studies suggest that the new member of FGF family, FGF-10, plays a fundamental role in branching morphogenesis and is essential for lung formation. FGF-10-deficient mice exhibit complete absence of lungs. FGF-7 promotes epithelial proliferation and expansion leading to the formation of cystlike structures. The aim of this study was to determine the gene level expression of FGF-10 and FGF-7 in the lung of nitrofen-induced CDH.

METHODS

Congenital diaphragmatic hernia (CDH) was induced in pregnant rats after administration of 100 mg of nitrofen on day 9.5 of gestation (term, 22 days). In control animals, the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 3 groups: normal controls (n = 16), nitrofen induced without CDH (n = 16), and nitrofen-induced CDH (n = 16). Total RNA and DNA were extracted from the lung in each group and measured. mRNA was extracted from total RNA. Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expressions of FGF-10 and FGF-7. Levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a house-keeping gene.

RESULTS

FGF-10 mRNA expression was decreased significantly in CDH lung (2.914 +/- 0.320) compared with controls (4.062 +/- 0.307; P <.05) and nitrofen induced without CDH lung (3.923 +/- 0.250; P <.01). FGF-7 mRNA expression was decreased significantly in CDH lung (0.777 +/- 0.097) compared with controls (1.028 +/- 0.093; P <.01).

CONCLUSIONS

Decreased gene expression of FGF-10 and FGF-7 in the hypoplastic lung suggests that pulmonary hypoplasia in nitrofen-induced CDH rat may be caused by reduced synthesis of FGF-10 and FGF-7 during lung morphogenesis.

Transgenic (UCP1-TG) mice with ectopic expression of UCP1 in skeletal muscle (SM) show a phenotype of increased energy expenditure, improved glucose tolerance and increase substrate metabolism in SM. To investigate the potential role of skeletal muscle AMPKα2 activation in the metabolic phenotype of UCP1-TG mice we generated double transgenic (DTG) mice, by crossing of UCP1-TG mice with DN-AMPKα2 mice overexpressing a dominant negative α2 subunit of AMPK in SM which resulted in an impaired AMPKα2 activity by 90±9% in SM of DTG mice. Biometric analysis of young male mice showed decreased body weight, lean and fat mass for both UCP1-TG and DTG compared to WT and DN-AMPKα2 mice. Energy intake and weight-specific total energy expenditure were increased, both in UCP1-TG and DTG mice. Moreover, glucose tolerance, insulin sensitivity and fatty acid oxidation were not altered in DTG compared to UCP1-TG. Also uncoupling induced induction and secretion of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) from SM was preserved in DTG mice. However, voluntary physical cage activity as well as ad libitum running wheel access during night uncovered a severe activity intolerance of DTG mice. Histological analysis showed a progressive degenerative morphology in SM of DTG mice which was not observed in SM of UCP1-TG mice. Moreover, ATP-depletion related cellular stress response via heat shock protein 70 was highly induced, whereas capillarization regulator VEGF was suppressed in DTG muscle. In addition, AMPKα2-mediated induction of mitophagy regulator ULK1 was suppressed in DTG mice, as well as mitochondrial respiratory capacity and content. In conclusion, we demonstrate that AMPKα2 is dispensable for SM mitochondrial uncoupling induced metabolic effects on whole body energy balance, glucose homeostasis and insulin sensitivity. But strikingly, activation of AMPKα2 seems crucial for maintaining SM function, integrity and the ability to compensate chronic metabolic stress induced by SM mitochondrial uncoupling.

The liver responds to fasting-refeeding cycles by reprogramming expression of metabolic genes. Fasting potently induces one of the key hepatic hormones, <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), to promote lipolysis, fatty acid oxidation, and ketogenesis, whereas refeeding suppresses its expression. We previously reported that the basic leucine zipper transcription <em>factor</em> E4BP4 (E4 binding protein 4) represses Fgf<em>21</em> expression and disrupts its circadian oscillations in cultured hepatocytes. However, the epigenetic mechanism for E4BP4-dependent suppression of Fgf<em>21</em> has not yet been addressed. Here we present evidence that histone methyltransferase G9a mediates E4BP4-dependent repression of Fgf<em>21</em> during refeeding by promoting repressive histone modification. We find that Fgf<em>21</em> expression is up-regulated in E4bp4 knock-out mouse liver. We demonstrate that the G9a-specific inhibitor BIX01294 abolishes suppression of the Fgf<em>21</em> promoter activity by E4BP4, whereas overexpression of E4bp4 leads to increased levels of dimethylation of histone 3 lysine 9 (H3K9me2) around the Fgf<em>21</em> promoter region. Furthermore, we also show that E4BP4 interacts with G9a, and knockdown of G9a blocks repression of Fgf<em>21</em> promoter activity and expression in cells overexpressing E4bp4. A G9a mutant lacking catalytic activity, due to deletion of the SET domain, fails to inhibit the Fgf<em>21</em> promoter activity. Importantly, acute hepatic knockdown by adenoviral shRNA targeting G9a abolishes Fgf<em>21</em> repression by refeeding, concomitant with decreased levels of H3K9me2 around the Fgf<em>21</em> promoter region. In summary, we show that G9a mediates E4BP4-dependent suppression of hepatic Fgf<em>21</em> by enhancing histone methylation (H3K9me2) of the Fgf<em>21</em> promoter.

We identified a homozygous missense mutation (c.196G->>T) in <em>fibroblast</em> <em>growth</em> <em>factor</em> 3 (FGF3) in <em>21</em> affected individuals from a large extended consanguineous Saudi family, phenotypically characterized by autosomal recessive syndromic congenital sensorineural deafness, microtia and microdontia. All affected family members are descendents of a common ancestor who had lived six generations ago in a geographically isolated small village. This is the second report of FGF3 involvement in syndromic deafness in humans, and independently confirms the gene's positive role in inner ear development. The c.196G->>T mutation results in substitution of glycine by cysteine at amino acid 66 (p.G66C). This residue is conserved in several species and across 18 FGF family members. Conserved glycine/proline residues are central to the 'beta-trefoil fold' characteristic of the secondary structure of FGF family proteins and substitution of these residues is likely to disrupt structure and consequently function.

<AbstractText>The objective of this study was to measure changes in glucose, lipid, and inflammation parameters after transitioning from a baseline diet (BD) to an isocaloric ketogenic diet (KD).</AbstractText><p><div><b>METHODS</b></div>Glucose homeostasis, lipid homeostasis, and inflammation were studied in 17 men (BMI: 25-35 kg/m² ) during 4 weeks of a BD (15% protein, 50% carbohydrate, 35% fat) followed by 4 weeks of an isocaloric KD (15% protein, 5% carbohydrate, 80% fat). Postprandial responses were assessed following mixed-meal tests matched to compositions of the BD (control meal [CM]) and KD (ketogenic meal).</p><AbstractText>Fasting ketones, glycerol, free fatty acids, glucagon, adiponectin, gastric inhibitory peptide, total and low-density lipoprotein cholesterol, and C-reactive protein were significantly increased on the KD. Fasting insulin, C-peptides, triglycerides, and <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> were significantly decreased. During the KD, the glucose area under the curve was significantly higher with both test meals, and the insulin area under the curve was significantly higher only for the CM. Analyses of glucose homeostasis suggested that the KD insulin sensitivity decreased during the CM but increased during the ketogenic meal. Insulin-mediated antilipolysis was decreased on the KD regardless of meal type.</AbstractText><AbstractText>Switching to the KD was associated with increased cholesterol and inflammatory markers, decreased triglycerides, and decreased insulin-mediated antilipolysis. Glucose homeostasis parameters were diet dependent and test meal dependent.</AbstractText>

The expression of basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (bFGF) mRNA and bFGF receptor mRNA was investigated in developing rat brain. In embryonic rat brain days 13-<em>21</em> (E13-E<em>21</em>), an abundant 1.8 kb bFGF mRNA was detected. Expression of 1.8 kb bFGF mRNA was the highest at E17 to E19 and was relatively undetectable 20 days after birth. However, very little mitogenic activity was associated with prenatal brain. On the other hand, multiple bFGF mRNA species of 6.0, 3.7, 2.5, 1.8, 1.6, 1.4 and 1.0 kb were detected in total adult rat brain and a significant amount of mitogenic activity was present. Differential and spatial bFGF mRNA expression was found in different parts of developing rat brain. Embryonic hypothalamus was found to contain the 1.8 kb bFGF mRNA while the 6.0 kb bFGF mRNA transcript was predominant in adult hypothalamus. Adult pituitary and cortex transcribed the lower molecular weight mRNAs but not the 6.0 kb mRNA. Expression of high-affinity bFGF receptor (flg) mRNA was found to be temporally regulated. flg 4.3 kb mRNA expression was high in embryonic rat brain (E13-E19). There appears to be coordinate expression between the 1.8 kb bFGF mRNA and flg. These results suggest that the expression of basic FGF mRNA is complex since it is both temporally and differentially regulated with different species being expressed at different times in development.

Viruses are the most abundant biological entities and carry a wide variety of genetic material, including the ability to encode host-like proteins. Here we show that viruses carry sequences with significant homology to several human peptide hormones including insulin, insulin-like <em>growth</em> <em>factors</em> (IGF)-1 and -2, FGF-19 and -<em>21</em>, endothelin-1, inhibin, adiponectin, and resistin. Among the strongest homologies were those for four viral insulin/IGF-1-like peptides (VILPs), each encoded by a different member of the family Iridoviridae VILPs show up to 50% homology to human insulin/IGF-1, contain all critical cysteine residues, and are predicted to form similar 3D structures. Chemically synthesized VILPs can bind to human and murine IGF-1/insulin receptors and stimulate receptor autophosphorylation and downstream signaling. VILPs can also increase glucose uptake in adipocytes and stimulate the proliferation of <em>fibroblasts</em>, and injection of VILPs into mice significantly lowers blood glucose. Transfection of mouse hepatocytes with DNA encoding a VILP also stimulates insulin/IGF-1 signaling and DNA synthesis. Human microbiome studies reveal the presence of these Iridoviridae in blood and fecal samples. Thus, VILPs are members of the insulin/IGF superfamily with the ability to be active on human and rodent cells, raising the possibility for a potential role of VILPs in human disease. Furthermore, since only 2% of viruses have been sequenced, this study raises the potential for discovery of other viral hormones which, along with known virally encoded <em>growth</em> <em>factors</em>, may modify human health and disease.

BACKGROUND

Age-related hepatic fat accumulation increases the risk of cardiometabolic diseases, and the <em>fibroblast</em> <em>growth</em> <em>factor</em> (FGF) <em>21</em>-resistant state caused by fatty liver underlies the pathogenesis of these diseases.

OBJECTIVE

Previous studies suggested that a higher level of cardiorespiratory fitness was associated with both lower hepatic fat content and serum FGF<em>21</em> levels; however, the effect of endurance exercise on hepatic fat content and serum FGF<em>21</em> concentration has not been studied. Therefore, we aimed to elucidate whether endurance exercise reduced hepatic fat content and serum FGF<em>21</em> levels.

METHODS

This is a randomized crossover trial.

METHODS

The study setting was an institutional practice.

METHODS

Thirty-three elderly Japanese men participated in the study.

METHODS

The intervention was a 5-week endurance exercise program comprising three cycle ergometer sessions per week.

METHODS

Hepatic fat content was assessed by proton magnetic resonance spectroscopy, and serum FGF<em>21</em> level was determined by ELISA.

RESULTS

A 5-week endurance exercise program decreased the hepatic fat content and serum FGF<em>21</em> levels without weight loss, and the changes were higher in the exercise period than in the control period (P = .0<em>21</em> and P = .026, respectively). Correlation analysis demonstrated that only the change in hepatic fat content was significantly and positively correlated with change in serum FGF<em>21</em> levels (r = 0.366, P = .006).

CONCLUSIONS

A 5-week endurance exercise program decreased hepatic fat content and serum FGF<em>21</em> levels without weight loss in elderly men, and exercise-induced hepatic fat reduction mediated the reduction in serum FGF<em>21</em> levels. These findings suggest that endurance exercise modulates hepatic fat content and FGF<em>21</em> resistance, regardless of obesity status.

Metabolic tissues, including skeletal muscle, adipose tissue and the digestive system, dynamically secrete various <em>factors</em> depending on the metabolic state, communicate with each other and orchestrate functions to maintain body homeostasis. Skeletal muscle secretes cytokines such as interleukin-6 (IL-6), IL-15, <em>fibroblast</em> <em>growth</em> <em>factor</em>-<em>21</em> (FGF<em>21</em>) and IL-8. These compounds, myokines, play important roles in biological homeostasis such as energy metabolism, angiogenesis and myogenesis. New technological advances have allowed secretomics - analysis of the secretome - to be performed. The application of highly sensitive mass spectrometry makes qualitative and quantitative analysis of the secretome of skeletal muscle possible. Secretory proteins derived from skeletal muscle cells under various conditions were analyzed, and many important <em>factors</em> were suggested. In-depth studies of the secretome from metabolic cells in various conditions are strongly recommended. This study will provide information on methods of novel communication between metabolic tissues.

BACKGROUND

Hepatokines such as fetuin-A or <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) are reasonable candidates affecting the pathophysiology of type 2 diabetes mellitus (T2DM). However, studies in humans at the onset of disease are scarce.

OBJECTIVE

The objective of the study was to compare FGF<em>21</em> and fetuin-A levels between adolescents with and without T2DM.

METHODS

This was a cross-sectional comparison of adolescents with and without T2DM.

METHODS

The study was conducted at diabetes and obesity treatment centers.

METHODS

Seventy-four predominantly Caucasian adolescents with T2DM aged 12-18 years and 74 body mass index (BMI)-, age-, and gender-matched controls participated in the study.

METHODS

There were no interventions.

METHODS

FGF<em>21</em> and fetuin-A and their correlation to age, BMI, glycated hemoglobin, blood pressure, lipids, adiponectin, and leptin were measured.

RESULTS

Adolescents with T2DM showed significant higher FGF<em>21</em> serum concentrations compared with obese controls without T2DM [median 277 pg/mL (interquartile range [IQR] 161-586) vs 200 pg/mL (IQR 116-323), respectively, P = .009] and higher fetuin-A serum concentrations (median 0.30 g/L (IQR 0.27-0.33) vs 0.28 g/L (IQR 0.25-0.30), respectively, P = .005). In a multiple linear regression analysis, fetuin-A was positively associated with glycated hemoglobin [β-coefficient 0.005 (95% confidence interval ± 0.004), P = .013], negatively with adiponectin (β-coefficient -0.004 (95% confidence interval ±0.002, P = .006) but not with BMI, age, gender, ethnicity, or leptin. FGF<em>21</em> was not associated with any parameter in multiple linear regression analysis.

CONCLUSIONS

Increased FGF<em>21</em> serum levels in obese adolescents with T2DM compared with obese adolescents without T2DM suggest a FGF<em>21</em>-resistant state in T2DM because FGF<em>21</em> improves insulin sensitivity. The increase of fetuin-A levels in obese adolescents with T2DM supports the hypothesis that fetuin-A is involved in the pathogenesis of T2DM because this hepatokine leads to insulin resistance.

OBJECTIVE

The very low-density lipoprotein receptor (VLDLR) plays an important role in the development of hepatic steatosis. In this study, we investigated the role of Peroxisome Proliferator-Activated Receptor (PPAR)β/δ and <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) in hepatic VLDLR regulation.

METHODS

Studies were conducted in wild-type and Pparβ/δ-null mice, primary mouse hepatocytes, human Huh-7 hepatocytes, and liver biopsies from control subjects and patients with moderate and severe hepatic steatosis.

RESULTS

Increased VLDLR levels were observed in liver of Pparβ/δ-null mice and in Pparβ/δ-knocked down mouse primary hepatocytes through mechanisms involving the heme-regulated eukaryotic translation initiation <em>factor</em> 2α (eIF2α) kinase (HRI), activating transcription <em>factor</em> (ATF) 4 and the oxidative stress-induced nuclear <em>factor</em> (erythroid-derived 2)-like 2 (Nrf2) pathways. Moreover, by using a neutralizing antibody against FGF<em>21</em>, Fgf<em>21</em>-null mice and by treating mice with recombinant FGF<em>21</em>, we show that FGF<em>21</em> may protect against hepatic steatosis by attenuating endoplasmic reticulum (ER) stress-induced VLDLR upregulation. Finally, in liver biopsies from patients with moderate and severe hepatic steatosis, we observed an increase in VLDLR levels that was accompanied by a reduction in PPARβ/δ mRNA abundance and DNA-binding activity compared with control subjects.

CONCLUSIONS

Overall, these findings provide new mechanisms by which PPARβ/δ and FGF<em>21</em> regulate VLDLR levels and influence hepatic steatosis development.

Brain-derived neurotropic <em>factor</em> (BDNF) mediates many aspects of neuronal function, and plays a chief role in the central regulation of energy balance. In the periphery, it is expressed in organs involved in energy, lipid, and glucose homeostasis, including the liver, but its role there remains unclear. Here, we describe studies examining the effect of selectively depleting hepatic BDNF. Liver-specific mutant mice exhibited normal food intake and body weights when fed standard chow or high-fat diets (HFDs). However, whereas HFD intake induced mild hyperglycemia and hyperinsulinemia in wild-types (WTs), liver-specific BDNF mutants were protected from these effects. Serum levels of cholesterol and triglycerides were also elevated in HFD-fed WTs, but they were normal or slightly increased in BDNF mutants. Furthermore, whereas WTs fed HFD exhibited elevated levels of circulating alanine aminotransferase and aspartate aminotransferase, BDNF mutant males fed a similar diet had a normal content of both enzymes. Molecular analysis indicated that the livers of BDNF mutants fed HFD contained elevated levels of peroxisome proliferator-activated receptor alpha (Pparalpha or Ppara as listed in the MGI Database) and <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (Fgf<em>21</em>) transcripts compared with WTs. This is a notable finding as this pathway has anti-diabetic and lipid clearance effects. Accordingly, genes involved in lipid and glucose handling and targets of PPARalpha and FGF<em>21</em> were upregulated in the BDNF mutant livers. The collective data indicate that hepatic BDNF might facilitate the emergence of insulin resistance, dyslipidemia, and liver disease following HFD challenge by suppressing PPARalpha and FGF<em>21</em>.

Dietary leucine was incrementally restricted to test whether limiting this essential amino acid (EAA) would fully reproduce the beneficial responses produced by dietary methionine restriction. Restricting leucine by 85% increased energy intake and expenditure within 5 to 7 days of its introduction and reduced overall accumulation of adipose tissue. Leucine restriction (LR) also improved glucose tolerance, increased hepatic release of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> into the blood stream, and enhanced insulin-dependent activation of Akt in liver. However, LR had no effect on hepatic lipid levels and failed to lower lipogenic gene expression in the liver. LR did affect remodeling of white and brown adipose tissues, increasing expression of both thermogenic and lipogenic genes. These findings illustrate that dietary LR reproduces many but not all of the physiological responses of methionine restriction. The primary differences occur in the liver, where methionine and LR cause opposite effects on tissue lipid levels and expression of lipogenic genes. Altogether, these findings suggest that the sensing systems which detect and respond to dietary restriction of EAAs act through mechanisms that both leucine and methionine are able to engage, and in the case of hepatic lipid metabolism, may be unique to specific EAAs such as methionine.

Gestational diabetes mellitus (GDM) is defined as the presence of high blood glucose levels with the onset, or detected for the first time during pregnancy, as a result of increased insulin resistance. GDM may be induced by dysregulation of pancreatic β-cell function and/or by alteration of secreted gestational hormones and peptides related with glucose homeostasis. It may affect one out of five pregnancies, leading to perinatal morbidity and adverse neonatal outcomes, and high risk of chronic metabolic and cardiovascular injuries in both mother and offspring. Currently, GDM diagnosis is based on evaluation of glucose homeostasis at late stages of pregnancy, but increased age and body-weight, and familiar or previous occurrence of GDM, may conditionate this criteria. In addition, an earlier and more specific detection of GDM with associated metabolic and cardiovascular risk could improve GDM development and outcomes. In this sense, 1st-2nd trimester-released biomarkers found in maternal plasma including adipose tissue-derived <em>factors</em> such as adiponectin, visfatin, omentin-1, fatty acid-binding protein-4 and retinol binding-protein-4 have shown correlations with GDM development. Moreover, placenta-related <em>factors</em> such as sex hormone-binding globulin, afamin, fetuin-A, <em>fibroblast</em> <em>growth</em> <em>factors</em>-<em>21</em>/23, ficolin-3 and follistatin, or specific micro-RNAs may participate in GDM progression and be useful for its recognition. Finally, urine-excreted metabolites such as those related with serotonin system, non-polar amino-acids and ketone bodies, may complete a predictive or early-diagnostic panel of biomarkers for GDM.

OBJECTIVE

The family of acyl-CoA synthetase enzymes (ACSL) activates fatty acids within cells to generate long chain fatty acyl CoA (FACoA). The differing metabolic fates of FACoAs such as incorporation into neutral lipids, phospholipids, and oxidation pathways are differentially regulated by the ACSL isoforms. In vitro studies have suggested a role for ACSL5 in triglyceride synthesis; however, we have limited understanding of the in vivo actions of this ACSL isoform.

METHODS

To elucidate the in vivo actions of ACSL5 we generated a line of mice in which ACSL5 expression was ablated in all tissues (ACSL5 (-/-) ).

RESULTS

Ablation of ACSL5 reduced ACSL activity by ∼80% in jejunal mucosa, ∼50% in liver, and ∼37% in brown adipose tissue lysates. Body composition studies revealed that ACSL5 (-/-) , as compared to control ACSL5 (loxP/loxP) , mice had significantly reduced fat mass and adipose fat pad weights. Indirect calorimetry studies demonstrated that ACSL5 (-/-) had increased metabolic rates, and in the dark phase, increased respiratory quotient. In ACSL5 (-/-) mice, fasting glucose and serum triglyceride were reduced; and insulin sensitivity was improved during an insulin tolerance test. Both hepatic mRNA (∼16-fold) and serum levels of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) (∼13-fold) were increased in ACSL5 (-/-) as compared to ACSL5 (loxP/loxP) . Consistent with increased FGF<em>21</em> serum levels, uncoupling protein-1 gene (Ucp1) and PPAR-gamma coactivator 1-alpha gene (Pgc1α) transcript levels were increased in gonadal adipose tissue. To further evaluate ACSL5 function in intestine, mice were gavaged with an olive oil bolus; and the rate of triglyceride appearance in serum was found to be delayed in ACSL5 (-/-) mice as compared to control mice.

CONCLUSIONS

In summary, ACSL5 (-/-) mice have increased hepatic and serum FGF<em>21</em> levels, reduced adiposity, improved insulin sensitivity, increased energy expenditure and delayed triglyceride absorption. These studies suggest that ACSL5 is an important regulator of whole-body energy metabolism and ablation of ACSL5 may antagonize the development of obesity and insulin resistance.

OBJECTIVE

To investigate whether resveratrol (3,4,5-trihydroxy-trans-stilbene) inhibits collagen I synthesis induced by insulin growth factor-1 (IGF-1) in intestinal fibroblasts, and to explore the possible molecular mechanisms.

METHODS

Male Sprague-Dawley rats were randomly divided into two groups: a control group and a 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis group. After 21 d of TNBS administration, the degree of inflammation and fibrosis in colon was measured by HE staining and Masson's trichrome staining. Western blotting was used to examine collagen I, IGF-1 and silent information regulator 1 (SIRT1) protein expression in colitis tissues. Western blotting and quantitative real-time polymerase chain reaction were used to characterize collagen I protein and col1a2 mRNA expression in mouse intestinal fibroblasts and CCD-(18)Co cells treated with IGF-1. A MEK inhibitor (U0126) was used to determine whether IGF-1-induced collagen I expression was mediated by extracellular signal-regulated kinase 1/2 (ERK1/2)-dependent mechanism. Effects of resveratrol on collagen I protein level, insulin growth factor-1 receptor (IGF-1R) and ERK1/2 phosphorylation levels were also examined after IGF-1 treatment in fibroblasts. To evaluate whether SIRT1 was necessary for the anti-fibrosis effect of resveratrol, cells were transfected with SIRT1-specific small interfering RNAs, wild-type SIRT1, and deacetylase-inactive mutant SIRT1.

RESULTS

Collagen I and IGF-1 expression was increased, and SIRT1 expression was decreased (0.67 ± 0.04 vs 1.05 ± 0.07, P < 0.001) in TNBS-induced colitis compared with the control group. In vitro, IGF-1 could induce collagen I expression, mainly through the ERK 1/2 signal pathway. Resveratrol reduced basal and IGF-1-induced collagen I gene and protein expression in intestinal fibroblasts. Overexpression of wild-type SIRT1, not deacetylase-inactive mutant SIRT1, decreased expression of collagen I induced by IGF-1. Moreover, silencing SIRT1 restored collagen I expression in fibroblasts challenged with resveratrol. However, disruption of SIRT1 did not influence the anti-fibrotic effects of resveratrol and IGF-1-induced collagen I expression. Further analysis revealed that resveratrol significantly decreased phosphorylation of IGF-1R and its downstream signaling molecules by inhibiting IGF-1 binding to its receptor.

CONCLUSIONS

Our data suggest that resveratrol effectively inhibits collagen I synthesis in IGF-1-stimulated fibroblasts, partly by inhibiting IGF-1R activation, and SIRT1 is also responsible for the process.

<AbstractText>Transcriptomic analysis of gene expression in brown adipose tissue (BAT) from mice in response to cold revealed strong induction of <em>growth</em> and differentiation <em>factor</em> 15 (GDF15). This study aimed to characterize GDF15 as a brown adipokine released in response to thermogenic activation and to determine its target functions.</AbstractText><AbstractText>GDF15 expression was measured in adipose tissues from mice in response to physiological and pharmacological modulators of thermogenesis. Brown and beige cell cultures were used to dissect the mechanisms regulating GDF15 expression. Brown adipocyte cellular models of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> and β-klotho invalidation were employed to identify the autocrine regulators of GDF15. RAW 264.7 macrophages were used to explore the targeting of GDF15 released by brown adipocytes.</AbstractText><AbstractText>Cold exposure of mice strongly induced GDF15 expression in BAT. Norepinephrine and cyclic adenosine monophosphate induced GDF15 expression and release by cells through protein kinase A-mediated mechanisms. Noradrenergic regulation of GDF15 required the active <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> pathway in brown adipocytes. GDF15 released by brown adipocytes targeted macrophages and downregulated the expression of proinflammatory genes.</AbstractText><AbstractText>GDF15 is a brown adipokine released by brown and beige cells in response to thermogenic activity. GDF15 released by BAT targets macrophages and may mediate downregulation of local inflammatory pathways.</AbstractText>

Carbohydrate-response element-binding protein (ChREBP) has been identified as a transcription <em>factor</em> that binds to carbohydrate response element in the promoter of pyruvate kinase, liver and red blood cells. ChREBP is activated by metabolites derived from glucose and suppressed by adenosine monophosphate (AMP), ketone bodies and cyclic cAMP. ChREBP regulates gene transcription related to glucose and lipid metabolism. Findings from knockout mice and human subjects suggest that ChREBP helps to induce hepatic steatosis, dyslipidemia, and glucose intolerance. Moreover, in tumor cells, ChREBP promotes aerobic glycolysis through p53 inhibition, resulting in tumor cell proliferation. Anti-diabetic and anti-lipidemic drugs such as atorvastatin, metformin, bile acid sequestrants, docosahexaenoic acid and eicosapentaenoic acid may affect ChREBP transactivity. Secretory proteins such as <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> and ANGPTL8 (Betatrophin) may be promising candidates for biologic markers reflecting ChREBP transactivity. Thus, ChREBP is associated with metabolic diseases and cancers, and may be a link between them.

OBJECTIVE

To determine the value of <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), a recently discovered biomarker for mitochondrial disease, in predicting clinical disease severity and disease progression in adult carriers of the m.3243A>G mutation.

METHODS

In the context of a national inventory, the heteroplasmy levels of the m.3243A>G mutation were measured in leukocytes and urinary epithelial cells. The Newcastle Mitochondrial Disease Adult Scale score was determined and blood was drawn for measuring FGF<em>21</em> concentration. Twenty-five of the included initial patients studied were then selected randomly for a follow-up study.

RESULTS

This prognostic study included 99 adult carriers of the m.3243A>G mutation. Our analysis revealed a moderate, significant correlation between FGF<em>21</em> concentration and disease severity (r = 0.49; p = <0.001). No significant correlations were found between disease severity and the heteroplasmy percentage determined in urinary epithelial cells or the heteroplasmy percentage determined in leukocytes. Weak but significant correlations were also found between FGF<em>21</em> concentration and the severity of the myopathy (r = 0.38; p = <0.001) and between the concentration of FGF<em>21</em> and the severity of the encephalopathy (r = 0.30; p = <0.001). Repeated measurements following 25 subjects for 2 years revealed no significant correlation between FGF<em>21</em> concentration and disease progression.

CONCLUSIONS

Measuring FGF<em>21</em> concentration had little added value in monitoring and predicting the disease course in this specific patient group.

Cardiovascular disease (CVD) is one of the most severe diseases in clinics. <em>Fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>) is regarded as an important metabolic regulator playing a therapeutic role in diabetes and its complications. The heart is a key target as well as a source of FGF<em>21</em> which is involved in heart development and also induces beneficial effects in CVDs. Our review is to clarify the roles of FGF<em>21</em> in CVDs. Strong evidence showed that the development of CVDs including atherosclerosis, coronary heart disease, myocardial ischemia, cardiac hypertrophy, and diabetic cardiomyopathy is associated with serum FGF<em>21</em> levels increase which was regarded as a compensatory response to induced cardiac protection. Furthermore, administration of FGF<em>21</em> suppressed the above CVDs. Mechanistic studies revealed that FGF<em>21</em> induced cardiac protection likely by preventing cardiac lipotoxicity and the associated oxidative stress, inflammation, and apoptosis. Normally, FGF<em>21</em> induced therapeutic effects against CVDs via activation of the above kinases-mediated pathways by directly binding to the FGF receptors of the heart in the presence of β-klotho. However, recently, <em>growing</em> evidence showed that FGF<em>21</em> induced beneficial effects on peripheral organs through an indirect way mediated by adiponectin. Therefore whether adiponectin is also involved in FGF<em>21</em>-induced cardiac protection still needs further investigation.

<AbstractText>The relationship between plasma <em>fibroblast</em> <em>growth</em> <em>factor</em> <em>21</em> (FGF<em>21</em>), insulin resistance, and steatohepatitis has not been systematically assessed.</AbstractText><AbstractText>To determine if higher plasma FGF<em>21</em> is associated with worse steatohepatitis on liver biopsy in patients with nonalcoholic fatty liver disease (NAFLD).</AbstractText><AbstractText>Cross-sectional study in a university hospital.</AbstractText><AbstractText>Patients with a body mass index >25 (n = 187) underwent: (i) euglycemic hyperinsulinemic clamp to assess tissue-specific insulin resistance (IR); (ii) liver magnetic resonance spectroscopy for intrahepatic triglyceride quantification, (iii) liver biopsy (if NAFLD present; n = 146); and (iv) fasting plasma FGF<em>21</em> levels.</AbstractText><AbstractText>Patients were divided into three groups: (i) No NAFLD (n = 41); (ii) No nonalcoholic steatohepatitis (NASH) (patients with isolated steatosis or borderline NASH; n = 52); and (iii) NASH (patients with definite NASH; n = 94). Groups were well-matched for age/sex, prevalence of type 2 diabetes mellitus, and hemoglobin A1c. During euglycemic hyperinsulinemic insulin clamp, insulin sensitivity in skeletal muscle and adipose tissue worsened from No NAFLD to NASH (both P < 0.001). Plasma FGF<em>21</em> levels correlated inversely with insulin sensitivity in adipose tissue (r = -0.17, P = 0.006) and skeletal muscle (r = -0.23, P = 0.007), but not with liver insulin sensitivity. Plasma FGF<em>21</em> was higher in patients with NASH (453 ± 262 pg/mL) when compared with the No NASH (341 ± 198 pg/mL, P = 0.03) or No NAFLD (325 ± 289 pg/mL, P = 0.02) groups. Plasma FGF<em>21</em> increased with the severity of necroinflammation (P = 0.02), and most significantly with worse fibrosis (P < 0.001), but not with worsening steatosis (P = 0.60).</AbstractText><AbstractText>Plasma FGF<em>21</em> correlates with severity of steatohepatitis, in particular of fibrosis, in patients with NASH. Measurement of FGF<em>21</em> may help identify patients at the highest risk of disease progression.</AbstractText>

Oral squamous cell carcinoma (OSCC) is among the most commonly diagnosed malignancies in the world. Patients with OSCC often develop treatment resistance, resulting in a poor prognosis. Mounting evidence indicates that interactions between cancerous cells and other components of the tumor microenvironment (TME) determine their response to treatment. Herein, we examined the role of cancer stem cell-derived extracellular vesicles (CSC_EVs) generated from CAL27 and SCC-15 OSCC cells in the development of cisplatin (CDDP) resistance. We demonstrated that CSC_EVs enhance CDDP resistance, clonogenicity, and the tumorsphere formation potential of OSCC cells. Our bioinformatics analyses revealed that OSCC_EVs are enriched with microRNA (miR)-<em>21</em>-5p and are associated with increased metastasis, stemness, chemoresistance, and poor survival in patients with OSCC. Mechanistically, enhanced activity of CSC_EVs was positively correlated with upregulated β-catenin, phosphatidylinositol-3 kinase (PI3K), signal transducer and activator of transcription 3 (STAT3), mammalian target of rapamycin (mTOR), and transforming <em>growth</em> <em>factor</em> (TGF)-β1 messenger (m)RNA and protein expression levels. CSC_EVs also conferred a cancer-associated <em>fibroblast</em> (CAF) phenotype on normal gingival <em>fibroblasts</em> (NGFs), with the resultant CAFs enhancing the oncogenicity of OSCC cells. Interestingly, treatment with ovatodiolide (OV), the bioactive component of <i>Anisomeles</i><i>indica</i>, suppressed OSCC tumorigenesis by reducing the cargo content of EVs derived from CSCs, suppressing self-renewal, and inhibiting the NGF-CAF transformation by disrupting EV-TME interactions. Moreover, by suppressing miR-<em>21</em>-5p, STAT3, and mTOR expressions in CSC_EVs, OV re-sensitized CSCs to CDDP and suppressed OSCC tumorigenesis. In vivo, treatment with OV alone or in combination with CDDP significantly reduced the tumor sphere-forming ability and decreased EV cargos containing mTOR, PI3K, STAT3, β-catenin, and miR-<em>21</em>-5p. In summary, our findings provide further strong evidence of OV's therapeutic effect in OSCC.

Herpes simplex virus type 1 (HSV-1) infection of the cornea induces vascular endothelial <em>growth</em> <em>factor</em> A (VEGF-A)-dependent lymphangiogenesis that continues to develop well beyond the resolution of infection. Inflammatory leukocytes infiltrate the cornea and have been implicated to be essential for corneal neovascularization, an important clinically relevant manifestation of stromal keratitis. Here we report that cornea infiltrating leukocytes including neutrophils and T cells do not have a significant role in corneal neovascularization past virus clearance. Antibody-mediated depletion of these cells did not impact lymphatic or blood vessel genesis. Multiple pro-angiogenic <em>factors</em> including IL-6, angiopoietin-2, hepatocyte <em>growth</em> <em>factor</em>, <em>fibroblast</em> <em>growth</em> <em>factor</em>-2 (FGF-2), VEGF-A, and matrix metalloproteinase-9 were expressed within the cornea following virus clearance. A single bolus of dexamethasone at day 10 post infection (pi) resulted in suppression of blood vessel genesis and regression of lymphatic vessels at day <em>21</em> pi compared to control-treated mice. Whereas IL-6 neutralization had a modest impact on hemangiogenesis (days 14-<em>21</em> pi) and lymphangiogenesis (day <em>21</em> pi) in a time-dependent fashion, neutralization of FGF-2 had a more pronounced effect on the suppression of neovascularization (blood and lymphatic vessels) in a time-dependent, leukocyte-independent manner. Furthermore, FGF-2 neutralization suppressed the expression of all pro-angiogenic <em>factors</em> measured and preserved visual acuity.