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Objective: To evaluate the effects of uncoupling protein (UCP) 1, UCP2 and UCP3 gene variants on body composition and metabolic changes in response to chronic overfeeding and the recovery after the period of overfeeding. Subjects and design: Twenty-four normal weight men (21±2 y), who constituted 12 pairs of identical twins, ate a 4.2 MJ/day energy surplus, 6 days a week, during a period of 100 days. The subjects were asked to return to the laboratory for testing at 4 months and for a final examination 5 y after completion of the overfeeding protocol. Methods: Resting metabolic rate (RMR) measurements were performed before and after overfeeding. A 4.2 MJ test meal was consumed, after which calorimetric measurements were continued for 240 min. Total body fat was assessed by hydrodensitometry and total subcutaneous fat by the sum of eight skinfolds. Polymorphisms were typed by PCR and PCR-RFLP-techniques. Thyroid stimulating hormone (TSH) concentrations after a thyrotropin releasing hormone (TRH) injection were measured by radioimmunoassay (RIA). Results: The changes in body weight and adiposity were not different between UCP1 Bcl I, UCP2 alanine to valine (A55V), UCP2 insertion/deletion (I/D) or UCP3 Rsa I genotypes. However, the recovery from overfeeding was worse among G-allele carriers of the UCP1 Bcl I, I allele non-carriers of the UCP2 I/D, AV heterozygote subjects of the UCP2 A55V and CC subjects of the UCP3 Rsa I polymorphisms. RMR was lower both before (P=0.01) and after (P=0.001) overfeeding in subjects with the CC genotype of the UCP3 Rsa I polymorphism. Moreover, after overfeeding, the UCP2 A55V heterozygote and UCP3 Rsa I CC homozygote subjects had significantly higher respiratory quotient (RQ) values at rest (P

Herein we detected single nucleotide polymorphisms in MEF2B and UCP3 by DNA sequencing and the KASPar technology and analyzed their association with sheep growth traits. Two synonymous mutations, g.1826 C > T and g.10266 G > C, were detected, respectively, and they were found to be significantly associated with sheep growth traits (p T, the average body weight and chest and cannon circumference of sheep with the CC genotype were significantly higher than those of sheep with the CT and TT genotypes (p C, the average body weight and chest and cannon circumference of sheep with the GG genotype were significantly higher than those of sheep with the GC and CC genotypes (p < 0.05). Moreover, the average body weight of sheep with the CC/GG genotype was higher compared with those of other genotype combinations. We also assessed MEF2B and UCP3 expression in different sheep tissues, confirming their expression in all examined tissues. To summarize, we believe that the polymorphisms identified in MEF2B and UCP3 can serve as molecular markers for sheep growth traits.

Growth hormone receptor knockout (GHRKO) mice are smaller, long living, and have an increased metabolic rate compared with normal (N) littermates. However, it is known that thermoneutral conditions (30–32°C) elicit metabolic adaptations in mice, increasing the metabolic rate. Therefore, we hypothesized that environmental temperature would affect the expression profile of different adipose tissue depots in GHRKO mice. For this, N (n = 12) and GHRKO (n = 11) male mice were maintained at 23 or 30°C from weaning until 11 months of age. RNA sequencing from adipose tissue depots (epididymal—eWAT, perirenal—pWAT, subcutaneous—sWAT, and brown fat—BAT) was performed. Thermoneutrality increased body weight gain in GHRKO mice, but not in N mice. Only a few genes were commonly regulated by temperature in N and GHRKO mice. The BAT was the most responsive to changes in temperature in both N and GHRKO mice. BAT Ucp1 and Ucp3 expression were decreased to a similar extent in both N and GHRKO mice under thermoneutrality. In contrast, eWAT was mostly unresponsive to changes in temperature. The response to thermoneutrality in GHRKO mice was most divergent from N mice in sWAT. Relative weight of sWAT was almost 4 times greater in GHRKO mice. Very few genes were regulated in N mice sWAT when compared with GHRKO mice. This suggests that this WAT depot has a central role in the adaptation of GHRKO mice to changes in temperature.

Background As a laboratory animal resource, the ICR mouse is commonly used in a variety of research fields. However, information on differences in exercise-related characteristics in ICR mice derived from different lineages and the underlying mechanisms remains to be elucidated. In this study, we investigated the intrinsic exercise capacity and a magnitude of response to acute exercise, and sought to identify mechanisms contributing to difference in Korl:ICR (a novel ICR lineage recently established by the National Institute of Food and Drug Safety Evaluation, Korea) and two commercialized ICR lineages derived from different origins (viz., A:ICR mouse from Orient Bio Com, the United States, and B:ICR mouse from Japan SLC Inc., Japan). Results Results showed that despite no significant difference in body weight and weight-proportioned tissue mass of heart and skeletal muscles among groups, the relatively low intrinsic exercise capacity and exaggerated response to acute exercise were identified in B:ICR comparted with Korl:ICR and A:ICR, as reflected by total work and lactate threshold (LT). Also, the mitochondrial efficiency expressed as the complex 1 and complex 1 + 2 respiratory control ratio (RCR) values for cardiac mitochondrial O2 consumption in B:ICR was significantly lower than that in Korl:ICR with higher level of state 2 respiration by glutamate/malate and UCP3 expression in cardiac muscle. Conclusions Taken together, these results indicate that the intrinsic exercise capacity of ICR mouse varies according to lineages, suggesting the role of cardiac mitochondrial coupling efficiency as a possible mechanism that might contribute to differences in the intrinsic exercise capacity and magnitude of response to exercise.

Objectives: We aimed to examine the protective effects of dapagliflozin (dapa) on thoracic aortic constriction (TAC)-induced heart failure in a nondiabetic mouse model. More specifically, we determined the effects of dapa on uncoupling protein 3 (UCP3) activation and subsequent metabolic remodeling. Methods: Sixty C57BL/6J mice were divided into six groups for TAC surgery and received different doses of dapa via gavage for 4 weeks. Echocardiography was performed to evaluate cardiac structure and function. Histological and molecular markers of cardiac remodeling and metabolic changes were assessed through staining assays, RT-PCR, western blot, and ELISA. HL-1 cells were used to explore the role of UCP3 in metabolic remodeling through transfection with UCP3 siRNA. Results: Mice that received TAC exhibited elevated heart weight/body weight ratios (HW/BW), left ventricular (LV) hypertrophy, impaired LV ejection fraction, and increased rates of fibrosis and apoptosis, unlike mice that received sham operation. Treatment with dapa after TAC restored HW/BW, improved LV parameters, and reduced fibrosis and apoptosis. dapa changed the expression levels of enzymes involved in glucose and fatty acid (FA) metabolism, such as pyruvate dehydrogenase lipoamide kinase isozyme 4, glucose transporter 4, carnitine palmitoyltransferase-1α, carnitine O-acetyltransferase, carnitine O-octanoyltransferase, acyl-CoA thioesterase 1, acyl-CoA thioesterase 2, peroxisome proliferator-activated receptors α and β, proliferator-activated receptor-gamma coactivator-1α, and UCP3, relative to the levels in mice in the TAC group. UCP3 siRNA reduced the expression of AMP-activated protein kinase and of factors involved in FA oxidation in vitro. Conclusions: Dapa exhibits cardioprotective effects in the model and augments expression of UCP3, which may be involved in metabolic remodeling in the failing heart.

Background Browning of white adipose tissue (WAT) is a promising approach to obesity treatment. During browning, WAT transforms into beige adipose tissue through stimulation of the peroxisome proliferator activated receptor γ (PPARγ). Nutmeg, one of the Indonesian herbs, reportedly has dual roles as a PPARα/γ partial agonist. Even though nutmeg has been traditionally used in body weight reduction, there is limited information regarding the potential role of nutmeg in browning of WAT. Objectives In this study, we explored the effect of nutmeg seed extract (NuSE) as a potential inductor of WAT browning. Methods Twelve male Wistar rats, 5–6 weeks old, were divided into control and nutmeg groups. The rats in nutmeg group were given NuSE for 12 weeks by oral gavage. After 12 weeks, the rat's inguinal WAT and brown adipose tissue (BAT) were collected, weighed and stored at − 80°C until use. Results We observed that even though NuSE did not reduce the final body weight, it significantly reduced body weight gain. NuSE also increased protein levels of peroxisome proliferator activated receptor γ coactivator 1α (PGC‐1α) and uncoupling protein 3 (UCP3) significantly and tended to increase UCP2 and UCP1 levels. Furthermore, NuSE induced macroscopic and microscopic morphological changes of inguinal WAT, marked by significantly increased adipocyte numbers and decreased adipocyte size. Conclusions Even though NuSE did not increase UCP1 significantly, it potentially alters inguinal WAT characteristics and leads to browning through PGC‐1α and UCP3 induction. However, UCP3’s specific mechanism in WAT browning remains unclear. Our findings could contribute to obesity treatment in the future., White adipose tissue (WAT) browning has been considered as one of the promising approaches in obesity treatment. In WAT browning process, the characteristics of WAT are transformed into brown‐like adipose tissue (known as beige adipose tissue) via stimulation of peroxisome proliferator activated receptors γ (PPARγ) pathway. Interestingly, Indonesian society has been using nutmeg which may mimic browning effect via inducing macroscopic and microscopic morphological changes of iWAT, marked by significant increase of adipocyte number and decrease of adipocyte size. in addition, The increases in UCP1 and PGC‐1α along with histological changes reveal that NuSE may potentially alter the characteristic of iWAT that lead to browning process and contribute to obesity treatment.

Background Bariatric surgery is currently the most effective treatment for patients with severe obesity. Uncoupling proteins (UCP) 1, 2, and 3 play key roles in the regulation of energy balance and weight. Previous studies have suggested that changes in UCP1–3 genes could influence weight loss after bariatric surgery. However, it is still unclear if these UCPs are indeed involved in weight loss variability after surgery. Therefore, we performed a systematic review aiming to summarize the results of studies on this subject. Methods A literature search was performed for all studies that evaluated associations of UCP1–3 expressions and their polymorphisms with obesity-related outcomes after bariatric surgery. Results Twenty-six studies were eligible for inclusion in this systematic review. Among them, 18 evaluated UCP1–3 expressions while 8 studies investigated the association between UCP1–3 polymorphisms and weight loss after bariatric surgery. In general, UCP2 and UCP3 expressions in adipose tissue and skeletal muscle seem to be affected by metabolic changes of bariatric surgery, which might be influenced by the surgery type. Data on UCP1 expression in adipose tissue is still inconclusive. Only few studies investigated the association between polymorphisms in UCP1–3 genes and weight loss after bariatric surgery, with contradictory results. Conclusion Available studies suggest that changes caused by bariatric surgery could influence UCP2 and UCP3 expressions in adipose tissue and muscles, consequently affecting weight loss. However, because of the reduced number of studies, further studies are needed to confirm whether these UCPs and their polymorphisms are indeed involved in weight loss after bariatric surgery.

This study aimed to assess the impact of high-fat diet (HFD) and vitamin D3 supplementation on cardiac apoptosis, inflammation, oxidative stress, and cardiac uncoupling proteins (UCPs) 2&3 expression. Forty rats were fed either (45%) or (10%) fat diet with or without vitamin D3 (500 U/kg/day) for 6 months, then cardiac tissue expression of Bax, Bcl2, Fas, Fas-L (markers for apoptotic pathways), TNF-α, MDA7, GPX1 (inflammatory and oxidative markers) and UCP 2&3 were assessed. Results revealed the enhancement of intrinsic and extrinsic cardiomyocyte apoptosis cascades and increased inflammatory and oxidative burdens on the heart in HFD rats. Downregulation of UCP2 and upregulation of UCP3 gene expression at 6 months. After vitamin D3 supplementation with HFD, cardiac apoptotic, inflammatory and oxidative markers were mitigated and expression of UCP3 was downregulated and UCP2 was upregulated. This work highlights the novel cardioprotective effect of vitamin D3 in the experimental model of HFD feeding through the downregulation of UCP3.

Ryanodine receptor type-1 (RYR1) and Calsequestrin-1 (CASQ1) proteins, located in the sarcoplasmic reticulum (SR), are two of the main players in skeletal excitation–contraction (EC) coupling. Mutations in the human RYR1 gene (encoding for the SR Ca2+ release channel) and ablation in mice of CASQ1 (a SR Ca2+ binding protein) cause hypersensitivity to halogenated anesthetics (malignant hyperthermia [MH] susceptibility) and to heat (heat stroke; HS). As both MH and HS are characterized by excessive cytosolic Ca2+ levels and hypermetabolic responses, we studied the metabolism of 4-mo-old mice from two different lines that are MH/HS susceptible: knock-in mice carrying a human MH mutation (RYR1YS) and CASQ1-knockout (ko) mice. RYR1YS and, to a lesser degree, CASQ1-null mice show an increased volume of oxygen consumption (VO2) and a lower respiratory quotient (RQ) compared with WT mice (indicative of a metabolism that relies more on lipids). This finding is accompanied by a reduction in total body fat mass in both Y522S and CASQ1-null mice (again, compared with WT). In addition, we found that RYR1YS and CASQ1-null mice have an increased food consumption (+26.04% and +25.58% grams/day, respectively) and higher basal core temperature (+0.57°C and +0.54°C, respectively) compared with WT mice. Finally, Western blots and electron microscopy indicated that, in hyperthermic mice, (1) SERCA (used to remove myoplasmic Ca2+) and UCP3 (responsible for a thermogenic process that dissipates mitochondrial H+ gradient) are overexpressed, and (2) mitochondrial volume and percentage of damaged mitochondria are both increased. In conclusion, the MH/HS phenotype in RYR1YS and CASQ1-null mice is associated with an intrinsically increased basal metabolism.

This study was designed to examine the potentials of telomere length, mitochondria, and acute phase protein genes as novel biomarkers of gastrointestinal (GI) tract pathologies and meat quality traits. Chickens were fed a diet containing corticosterone (CORT) for 4 weeks and records on body weight, telomere length, GI tract and muscle histopathological test, meat quality traits, mitochondria, and acute phase protein genes were obtained at weeks 4 and 6 of age. The body weight of CORT-fed chickens was significantly suppressed (p &lt, 0.05). CORT significantly altered the GI tract and meat quality traits. The interaction effect of CORT and age on body weight, duodenum and ileum crypt depth, pH, and meat color was significant (p &lt, 0.05). CORT significantly (p &lt, 0.05) shortened buffy coat telomere length. UCP3 and COX6A1 were diversely and significantly expressed in the muscle, liver, and heart of the CORT-fed chicken. Significant expression of SAAL1 and CRP in the liver and hypothalamus of the CORT-fed chickens was observed at week 4 and 6. Therefore, telomere lengths, mitochondria, and acute phase protein genes could be used as novel biomarkers for GI tract pathologies and meat quality traits.

Background Left ventricular diastolic dysfunction, an early stage in the pathogenesis of heart failure with preserved ejection fraction, is exacerbated by joint exposure to hypertension and obesity; however, the molecular mechanisms involved remain uncertain. The mitochondrial UCP3 (uncoupling protein 3) is downregulated in the heart with obesity. Here, we used a rat model of UCP3 haploinsufficiency (ucp3 +/‐ ) to test the hypothesis that decreased UCP3 promotes left ventricular diastolic dysfunction during hypertension. Methods and Results Ucp3 +/‐ rats and ucp3 +/+ littermates fed a high‐salt diet (HS; 2% NaCl) and treated with angiotensin II (190 ng/kg per min for 28 days) experienced a similar rise in blood pressure (158±4 versus 155±7 mm Hg). However, UCP3 insufficiency worsened diastolic dysfunction according to echocardiographic assessment of left ventricular filling pressures (E/e’; 18.8±1.0 versus 14.9±0.6; P P P +/‐ rats. Histological and molecular analyses further revealed that UCP3 insufficiency accelerated left ventricular concentric remodeling, detrimental interstitial matrix remodeling, and fetal gene reprogramming during hypertension. Moreover, UCP3 insufficiency increased oxidative stress and led to greater impairment of protein kinase G signaling. Conclusions Our findings identified UCP3 insufficiency as a cause for increased incidence of left ventricular diastolic dysfunction during hypertension. The results add further support to the use of antioxidants targeting mitochondrial reactive oxygen species as an adjuvant therapy for preventing heart failure with preserved ejection fraction in individuals with obesity.

BACKGROUND In the present work, we investigated the cardioprotective potential of pyridoxal-5-phosphate (PLP) in old rats as a cofactor of enzymes that synthesize hydrogen sulphide (H2 S). MATERIALS AND METHODS PLP was administered per os in a dose of 0.7 mg per kg daily for 2 weeks. Rats were divided into three groups (adult, old and old +PLP) of 20 animals. The cardiac mRNA levels of genes encoding H2 S-synthesizing enzymes cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), uncoupling proteins (UCP3), subunits of ATP-sensitive potassium (KATP ) channels were determined using real-time polymerase chain reaction analysis. We also studied the effect of PLP-administration on the content of H2 S, oxidative stress, the activities of inducible and constitutive NO-synthase (iNOS, cNOS), arginase and nitrate reductase in the heart homogenates as well as cardiac resistance to ischemia-reperfusion in Langendorff-isolated heart model. RESULTS It was shown that PLP restored mRNA levels of CSE, 3-MST and UCP3 genes, and H2 S content and also significantly increased the expression of SUR2 and Kir6.1 (2.2 and 3.3 times, respectively) in the heart of old rats. PLP significantly reduced the formation of superoxide, malondialdehyde, diene conjugates as well as the activity of iNOS and arginase. PLP significantly increased constitutive synthesis of NO and prevented reperfusion disturbances of the heart function after ischemia. CONCLUSIONS Thus, PLP-administration in old rats was associated with up-expression of CSE, 3-MST, UCP3 and SUR2 and Kir6.1 subunits of KATP channels, and also increased cNOS activity and reduced oxidative stress and prevented reperfusion dysfunction of the heart in ischemia-reperfusion.

The Mulberry (Morus alba L.) fruit is a rich source of polyphenolic compounds, most of these are anthocyanins. Obesity is intimately related to low-grade inflammation, with increased pro-inflammatory cytokine secretion and macrophage infiltration in white adipose tissue (WAT). This study investigated whether mulberry fruit extract (ME) has beneficial effects on obesity-induced inflammation and skeletal muscle mitochondrial dysfunction. Sprague-Dawley rats were divided into four groups and fed either a low-fat diet (LFD), high-fat diet (HFD), HFD + 5 g/kg of ME (ME-L), or HFD + 10 g/kg of ME (ME-H) for 14 weeks. ME alleviated dyslipidemia and lipid accumulation, as well as pro-inflammatory cytokine production such as tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and monocyte chemoattractant protein 1 (MCP1) in the WAT. ME mitigated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation and macrophage infiltration in WAT. Notably, microRNA (miR)-21, miR-132, and miR-43 expressions were downregulated in the WAT of the ME groups compared to the HFD group. Moreover, ME increased the mitochondrial size and mitochondrial DNA (mtDNA) content, as well as key genes’ expression related to mitochondrial function, including sirtuin (SIRT)1, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), carnitine palmitoyltransferase 1β (CPT-1β), and uncoupling protein 3 (UCP3), and adenosine monophosphate-activated protein kinase (AMPK)/SIRT activities in skeletal muscle. These results suggested that ME might alleviate obesity-induced inflammation and mitochondrial dysfunction by regulating miR-21, miR-132, and miR-43 expression in WAT, and by activating the PGC-1α/SIRT1 pathway in muscle.

Cajanolactone A (CLA) is a stilbenoid isolated from Cajanus canjan (L.) Millsp with the potential to prevent postmenopausal obesity. In this study, the effect of CLA on high-fat diet (HFD)-induced obesity in female C57BL/6 mice was investigated. It was found that, treatment with CLA reduced the energy intake and effectively protected the mice from HFD-induced body weight gain, fat accumulation within the adipose tissues and liver, and impairment in energy metabolism. Further investigation revealed that CLA significantly down-regulated the expression of ORX, ORXR2, pMCH, and Gal in the hypothalamus and antagonized HFD-induced changes in the expression of UCP1, Pgc-1α, Tfam, and Mfn1 in the inguinal white adipose tissue (iWAT); Caveolin-1, MT and UCP3 in the perigonadal white adipose tissue (pWAT); and Pdhb, IRS2, Mttp, Hadhb, and Cpt1b in the liver. CLA also protected the pWAT and liver from HFD-induced mitochondrial damage. However, neither HFD nor CLA showed an effect on the mass of brown adipose tissue (BAT) or the expression of UCP1 in the BAT. In summary, our findings suggest that CLA is a potential drug candidate for preventing diet-induced obesity, at least in females. CLA works most likely by suppressing the hypothalamic expression of orexigenic genes, which leads to reduced energy intake, and subsequently, reduced fat accumulation, thereby protecting the adipose tissues and the liver from lipid-induced mitochondrial dysfunction.

The toxidrome associated with death from the synthetic cathinones includes hyperthermia as part of the sympathomimetic syndrome. Here, we examine the gender differences in the development of tolerance to the hyperthermia mediated by the synthetic cathinone methylone. In addition to temperature changes, expression differences in genes encoding the uncoupling proteins (UCP) 1 & 3, and TGR5 in skeletal muscle (SKM) and brown adipose tissue (BAT) were examined. Male and female rats were treated weekly with methylone (10 mg/kg). The females developed a tolerance to the methylone-induced hyperthermia by week two of drug exposure. By the third week, females displayed a hypothermic response to methylone. Conversely, males continued to display a hyperthermic response up to and including week four. At week four, the males demonstrated a significantly lower hyperthermia and a complete tolerance seen at week five with no significant hyperthermia. Tissue samples collected after treatment on the sixth week indicate that chronic exposure to methylone reduced UCP1 expression in SKM and BAT of the female rats. Only the females displayed increased TGR5 expression in BAT. UCP3 expression increased in both the SKM and BAT of the males and females. The differences between responses in male and female subjects further demonstrate the need for gender studies in the toxicology associated with drugs with abuse potential.

Objective To determine whether occlusal alteration contributes to masticatory muscle damage by inducing oxidative stress. Design Thirty Sprague-Dawley rats were randomly divided into six groups, including occlusal interference groups (3 days, 7 days, 14 days, 21 days, and removal for 3 days) and a sham group. A rat experimental model of occlusal interference was generated by a 0.6-mm unilateral bite-raise. The rats were euthanised for evaluation of histologic changes in the masseter muscles using haematoxylin-eosin staining. To further investigate the role of oxidative stress and uncoupling protein (UCP3) in the development of occlusal dysfunction-induced masseter damage, levels of UCP3 protein were measured by western blot analysis. Results Compared with the sham group, the connective tissue of the masseter muscle was extended partially and inflammatory cells appeared following the induction of malocclusion. With respect to the oxidative stress markers, there were increases in malondialdehyde (MDA) content but decreases in superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities; furthermore, the expression of UCP3 was upregulated. After eliminating the occlusal interference for 3 days, the degree of inflammation was substantially alleviated, the MDA content decreased, and SOD and GPX activities increased. The expression of UCP3 decreased. Conclusions Occlusal interference induces oxidative stress in the masseter muscle, regulated by UCP3. Overall, these findings have significant implications for the understanding of how occlusal dysfunction causes muscle fatigue and pain.

High Ambient Temperature (AT) provokes Heat Stress (HS) in animals, which is characterized by increased body temperature, Reactive Oxygen Species (ROS) production and cell damage. Uncoupling Proteins (UCP) may contribute to dissipate body heat, cytochrome P450 (CYP3A4) reduces ROS and Heat Shock Proteins (HSP) prevent protein denaturalization. This study analyzed the expression of HSP70, UCP3 and CYP3A in liver, Longissimus Dorsi (LD) and Semitendinosus (ST) muscles of pigs exposed to HS conditions. A 21-d experiment was conducted with 18 pigs (32.6±3.2 kg body weight) divided into 3 treatments: (1) HS, pigs exposed to natural AT (29.5-37.2°C) fed ad libitum; (2) TNad, thermoneutral conditions (24.0±2.0°C) fed ad libitum; (3) TNpf, thermoneutral fed same amount as HS pigs. Hepatic expression of HSP70 in HS pigs was 4-fold higher than in TNad pigs (p=0.039); no differences were observed between HS and TNpf, or between TNad and TNpf pigs (p>0.10). There were no differences in HSP70 expression in both muscles (p>0.10) because of HS or feed intake. Expression of UCP3 in LD and ST did not differ (p>0.10) between treatments; neither the expression of CYP3A in liver was affected by HS, or feed intake level (p>0.10). Apparently, pigs became adapted to HS because expression of mitochondrial UCP3 and CYP3A was not affected after 21 d of HS exposure and the increased HSP70 expression in liver could have helped cells to maintain their proteins integrity.

Increased fat mass, which is induced by the storage of excess nutrients, is considered a causal factor for various metabolic disorders, including insulin resistance, type 2 diabetes, hyperlipidemia, hyperglycemia, hypertension, atherosclerosis, and non-alcoholic fatty liver disease. Therefore, it is necessary to prevent hyperadiposity to sustain a healthy life. Recently, uncoupling proteins (UCPs) were suggested to be molecular targets for curing obesity and its complications. In this study, green satsuma mandarin orange (Citrus unshiu) extract (GME) increased UCP3 expression in cultured myocytes. In a diet-induced obese animal model, administration of GME reduced fat mass and average fat cell size. Similar to in vitro experiments, GME restored expression of UCP3 in skeletal muscle. Moreover, GME also induced UCP2 expression in skeletal muscle. In conclusion, GME is suggested to be a novel functional dietary supplement for adiposity control through induction of UCPs.

While it has been hypothesized that brown adipocytes responsible for mammalian thermogenesis are absent in birds, the existence of beige fat has yet to be studied directly. The present study tests the hypothesis that beige fat emerges in birds as a mechanism of physiological adaptation to cold environments. Subcutaneous neck adipose tissue from cold-acclimated or triiodothyronine (T3)-treated chickens exhibited increases in the expression of avian uncoupling protein (avUCP, an ortholog of mammalian UCP2 and UCP3) gene and some known mammalian beige adipocyte-specific markers. Morphological characteristics of white adipose tissues of treated chickens showed increased numbers of both small and larger clusters of multilocular fat cells within the tissues. Increases in protein levels of avUCP and mitochondrial marker protein, voltage-dependent anion channel, and immunohistochemical analysis for subcutaneous neck fat revealed the presence of potentially thermogenic mitochondria-rich cells. This is the first evidence that the capacity for thermogenesis may be acquired by differentiating adipose tissue into beige-like fat for maintaining temperature homeostasis in the subcutaneous fat ‘neck warmer’ in chickens exposed to a cold environment. Supplementary Information The online version contains supplementary material available at 10.1007/s00726-021-02953-5.

Background: The study aimed to investigate whether ligustrazine, a traditional Chinese medicine, could attenuate myocardial ischemia/reperfusion (I/R) injury and explore the potential mechanism.Methods: 32 Sprague-Dawley rats were divided equally into four groups: sham operation (S); (I/R); I/R + ligustrazine preconditioning (Lig); I/R + ligustrazine preconditioning + mitochondrial permeability transition pore (mPTP) opener lonidamine (LND) (Lig + LND). Myocardial I/R model was established and ligustrazine was administered intraperitoneally 5 min prior to ischemia, LND was administered intraperitoneally 10 min prior to reperfusion. The infarct area (IA) was measured by Evans blue staining, where levels of Myocardial injury markers, malondialdehyde (MDA), superoxide dismutase (SOD), adenosine triphosphate (ATP) were detected. RT-PCR and Western Blot were adopted to measure the uncoupling protein 3 (UCP3) expression.Results: Compared to I/R group, the IA/area at risk (AAR) in Lig, and Lig + LND groups were significantly decreased, UCP3 levels of mRNA and protein were increased (P < 0.05). Compared to Lig group, the IA/AAR in Lig + LND group was significantly increased (P < 0.05). Ligustrazine pretreatment increased SOD, ATP activity, and decreased cardiac troponin I (cTnI), creatine kinase-muscle/brain (CK-MB), lactate dehydrogenase (LDH) and MDA activities. The effect of ligustrazine was reversed by LND.Conclusion: The present results indicated that ischemic preconditioning of ligustrazine might protect myocardium against I/R injury through upregulating UCP3 expression.

Brown adipose tissue (BAT) might be a beneficial mediator in the development and treatment of nonalcoholic steatohepatitis (NASH). We aim to evaluate the gene expression of BAT activity-related genes during the development and the dietary and surgical treatment of NASH. BAT was collected from male C57BL/6J mice that received a high fat-high sucrose diet (HF-HSD) or a normal chow diet (NCD) for 4 and 20 weeks (n=8–9 per dietary group and timepoint) and from mice that underwent dietary intervention (return to NCD) (n=8), roux-en-y gastric bypass (RYGB) (n=6), or sham procedure (n=6) after 12 weeks HF-HSD. Expression of BAT genes involved in lipid metabolism (Cd36 and Cpt1b; p

Exogenous lactate administration has more recently been investigated for its various prophylactic effects. Lactate derived from potential functional foods, such as fermented oyster extract (FO), may emerge as a practical and effective method of consuming exogenous lactate. The current study endeavored to ascertain whether the lactate derived from FO may act on muscle cell biology, and to what extent this may translate into physical fitness improvements. We examined the effects of FO in vitro and in vivo, on mouse C2C12 cells and exercise performance indicators in mice, respectively. In vitro, biochemical analysis was carried out to determine the effects of FO on lactate content and muscle cell energy metabolism, including adenosine triphosphate (ATP) activity. Western blot analysis was also utilized to measure the protein expression of total adenosine monophosphate-activated protein kinase (AMPK), p-AMPK (Thr172), lactate dehydrogenase (LDH), succinate dehydrogenase (SDHA) and peroxisome proliferator-activated receptor gamma coactivator-1&alpha, (PGC-1&alpha, ) in response to FO administration. Three experimental groups were formed: a positive control (PC) treated with 1% horse serum, FO10 treated with 10 &mu, g/mL and FO50 treated with 50 &mu, g/mL. In vivo, the effects of FO supplementation on exercise endurance were measured using the Rota-rod test, and Western blot analysis measured myosin heavy-chain 2 (MYH2) to assess skeletal muscle growth, alongside p-AMPK, total-AMPK, PGC-1&alpha, cytochrome C and UCP3 protein expression. Biochemical analysis was also performed on muscle tissue to measure the changes in concentration of liver lactate, lactate dehydrogenase (LDH), glycogen and citrate. Five groups (n = 10/per group) consisted of a control group (CON), exercise group (Ex), positive control treated with Ex and 500 mg/kg Taurine (Ex-Tau), Ex and 100 mg/kg FO supplementation (Ex-FO100) and Ex and 200 mg/kg FO supplementation (Ex-FO200) orally administered over the 4-week experimental period.FO50 significantly increased PGC-1&alpha, expression (p &lt, 0.001), whereas both FO10 and FO50 increased the expression of p-AMPK (p &lt, 0.001), in C2C12 muscle cells, showing increased signaling important for mitochondrial metabolism and biogenesis. Muscle lactate levels were also significantly increased following FO10 (p &lt, 0.05) and FO50 (p &lt, 0.001). In vivo, muscle protein expression of p-AMPK (p &lt, 0.05) and PGC-1&alpha, were increased, corroborating our in vitro results. Cytochrome C also significantly increased following FO200 intake. These results suggest that the effects of FO supplementation may manifest in a dose-response manner. FO administration, in vitro, and supplementation, in vivo, both demonstrate a potential for improvements in mitochondrial metabolism and biogenesis, and even for potentiating the adaptive effects of endurance exercise. Mechanistically, lactate may be an important molecule in explaining the aforementioned positive effects of FO.

Thyroid hormones are important for homeostatic control of energy metabolism and body temperature. Although skeletal muscle is considered a key site for thyroid action, the contribution of thyroid hormone receptor signaling in muscle to whole-body energy metabolism and body temperature has not been resolved. Here, we show that T3-induced increase in energy expenditure requires thyroid hormone receptor alpha 1 (TRα1 ) in skeletal muscle, but that T3-mediated elevation in body temperature is achieved in the absence of muscle-TRα1 . In slow-twitch soleus muscle, loss-of-function of TRα1 (TRαHSACre ) alters the fiber-type composition toward a more oxidative phenotype. The change in fiber-type composition, however, does not influence the running capacity or motivation to run. RNA-sequencing of soleus muscle from WT mice and TRαHSACre mice revealed differentiated transcriptional regulation of genes associated with muscle thermogenesis, such as sarcolipin and UCP3, providing molecular clues pertaining to the mechanistic underpinnings of TRα1-linked control of whole-body metabolic rate. Together, this work establishes a fundamental role for skeletal muscle in T3-stimulated increase in whole-body energy expenditure.

Skeletal muscle is the most abundant tissue in the adult body and plays an essential role in maintaining heat production for the entire body. Recently, muscle-derived non-shivering thermogenesis under cold conditions has received much attention. Zinc-α2-glycoprotein (ZAG) is an adipokine that was shown to influence energy metabolism in the adipose tissue. We used ZAG knock-out (ZAG KO) and wild-type (WT) mice to investigate the effect of ZAG on the lipid metabolism of skeletal muscle upon exposure to a low temperature (6°C) for one week. The results show that cold stress significantly increases the level of lipolysis, energy metabolism, and fat browning-related proteins in the gastrocnemius muscle of WT mice. In contrast, ZAG KO mice did not show any corresponding changes. Increased expression of β3-adrenoceptor (β3-AR) and protein kinase A (PKA) might be involved in the ZAG pathway in mice exposed cold stress. Furthermore, expression of lipolysis-related proteins (ATGL and p-HSL) and energy metabolism-related protein (PGC1α, UCP2, UCP3 and COX1) was significantly enhanced in ZAG KO mice after injection of ZAG-recombinant plasmids. These results indicate that ZAG promotes lipid-related metabolism in the skeletal muscle when the animals are exposed to low temperatures. This finding provides a promising target for the development of new therapeutic approaches to improve skeletal muscle energy metabolism.

The purpose of the present study was to investigate how the effects of high-fat diet feeding on the skeletal muscle persisted during aging using mice. Post-weaned male mice were fed a high-fat diet between 1- and 3-mo-old followed by return to supply a normal diet until 13-mo-old. Monthly physical tests demonstrated that age-related glucose intolerance that was generally developed after 10-mo-old in the control mice was significantly improved in mice fed a high-fat diet. Interestingly, mRNA expressions of Pdk4, Ucp3, and Zmynd17 were up-regulated by high-fat feeding and persisted in the tibialis anterior muscle until 13-mo-old. At Pdk4 and Ucp3 loci, enhanced distributions of active histone modifications were noted in the high-fat-fed mice at 13-mo-old. In contrast, age-related accumulation of histone variant H3.3 at these loci was suppressed. These results indicated that epigenetic modifications caused by early nutrition mediated the changes in skeletal muscle gene expression during aging.

Background: Sepsis can cause the nonthyroidal illness syndrome (NTIS), resulting in perturbed thyroid hormone (TH) signaling and reduced thyroxine (T4) levels. TH is a major regulator of muscle function, via its influence on mitochondria. This study aimed at evaluating the relationship between TH signaling, mitochondrial function, and the antioxidant defense system in the diaphragms of septic mice. Methods: Male C57Bl/6 mice were divided into two groups: cecal ligation and puncture (CLP) and sham. Twenty-four hours after surgery, plasma, diaphragms, and livers were collected. TH metabolism and responses were analyzed by measuring messenger RNA (mRNA) expression of Dio1 in the liver, and Thra, Thrb, Dio2, Slc16a10, and Slc16a2 (encodes MCT 10 and 8), in the diaphragm. T4 plasma levels were measured by radioimmunoassay. Damage to diaphragm mitochondria was assessed by electron microscopy and real-time polymerase chain reaction (qPCR), and function with oxygraphy. The diaphragm antioxidative defense system was examined by qPCR, analyzing superoxide dismutase (SOD) 1 (Sod1), mitochondrial superoxide dismutase (SOD 2; Sod2), extracellular superoxide dismutase (SOD 3; Sod3), glutathione peroxidase 1 (Gpx1), and catalase (Cat) expression. The effect of TH replacement was tested by treating the mice with T4 and triiodothyronine (T3) (CLP+TH) after surgery. Results: CLP mice presented reduced total plasma T4 concentrations, downregulated Dio1, and upregulated Il1b mRNA expression in the liver. CLP mice also displayed downregulated Thra, Thrb, Slc16a10, and Slc16a2 expression in the diaphragm, suggesting that TH signaling was compromised. The expression of Ppargc1a (encoding PGC1a) was downregulated, which correlated with the decrease in the number of total mitochondria, increase in the percentage of injured mitochondria, downregulation of respiratory chain complex 2 and 3 mRNA expression, and reduced maximal respiration. In addition, septic animals presented a three-fold increase in Ucp3 and G6pdh expression; downregulated Sod3, Gpx1, and Cat expression; and upregulated Sod2 expression, potentially due to elevated reactive oxygen species levels. The mitochondrial number and the percentage of injured mitochondrial were similar between sham and CLP+TH mice. Conclusions: Sepsis induced responses consistent with NTIS, resulted in mitochondrial damage and functional impairment, and modulated the expression of key antioxidant enzymes in the diaphragm. Thus, impaired diaphragm function during sepsis seems to involve altered local TH signaling, mitochondrial dysfunction, and oxidative stress defense.

Maternal dietary supplementation of n−3 polyunsaturated fatty acids (n−3 PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is considered to play positive roles in fetal neuro system development. However, maternal n−3 PUFAs may induce molecular reprogramming of uncommitted fetal myoblasts into adipocyte phenotype, in turn affecting lipid metabolism and energy expenditure of the offspring. The objective of this in vitro study was to investigate the combined effects of EPA and DHA on C2C12 cells undergoing brown adipogenic differentiation. C2C12 myoblasts were cultured to confluency and then treated with brown adipogenic differentiation medium with and without 50 μM EPA and 50 μM DHA. After differentiation, mRNA and protein samples were collected. Gene expression and protein levels were analyzed by real-time PCR and western blot. General Proteomics analysis was conducted using mass spectrometric evaluation. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XFP Analyzer. Cells treated with n−3 PUFAs had significantly less (P < 0.05) expression of the brown adipocyte marker genes PGC1α, DIO2, and UCP3. Expression of mitochondrial biogenesis-related genes TFAM, PGC1α, and PGC1β were significantly downregulated (P < 0.05) by n−3 PUFAs treatment. Expression of mitochondrial electron transportation chain (ETC)-regulated genes were significantly inhibited (P < 0.05) by n−3 PUFAs, including ATP5J2, COX7a1, and COX8b. Mass spectrometric and western blot evaluation showed protein levels of enzymes which regulate the ETC and Krebs cycle, including ATP synthase α and β (F1F0 complex), citrate synthase, succinate CO-A ligase, succinate dehydrogenase (complex II), ubiquinol-cytochrome c reductase complex subunits (complex III), aconitate hydratase, cytochrome c, and pyruvate carboxylase were all decreased in the n−3 PUFAs group (P < 0.05). Genomic and proteomic changes were accompanied by mitochondrial dysfunction, represented by significantly reduced oxygen consumption rate, ATP production, and proton leak (P < 0.05). This study suggested that EPA and DHA may alter the BAT fate of myoblasts by inhibiting mitochondrial biogenesis and activity and induce white-like adipogenesis, shifting the metabolism from lipid oxidation to synthesis.

It is well known that GLP-1 activates GLP-1R to reduce body weight by inhibiting eating. GLP-1 is cleaved by the neutral endopeptidase (NEP) 24.11 into a pentapeptide GLP-1 (32-36) amide, which increases basal energy expenditure and inhibits weight gain in obese mice. It is well known that GLP-1 analogs can reduce weight by suppressing eating. However, there are few reports of reducing weight through the dual effects of inhibiting eating and increasing basic energy. Here, we report the peptide EGLP-1, a GLP-1 analogue, which can reduce food intake and increase basal energy expenditure. In C2C12 myotubes, EGLP-1 can increase both phosphorylation of acetyl CoA carboxylase (ACC) and the ratio between phosphorylation of ACC and the total expression of ACC (pACC/ACC). In diet-induced obese mice, EGLP-1 is more effective than exendin-4 in reducing body weight, reducing fat mass and improving hepatic steatosis. At the same time, EGLP-1 can improve hyperglycemia, reduce food intake, and improve insulin resistance, just like exendin-4. In addition, EGLP-1, not exendin-4, can improve physiological parameters associated with lipid metabolism and increase oxygen consumption by increasing uncoupling proteins 3 (UCP3) expression and pACC/ACC ratio in skeletal muscle. Taken together, this data showed that EGLP-1 is able to reduce body weight by reducing food intake and increasing basal energy expenditure, suggesting it may be more effective in treating diabetic and non-diabetic overweight or obese people than pure GLP-1R agonist exendin-4.

Our previous study showed that feeding mice with vitamin D deficiency diet markedly alleviated high-fat-diet-induced overweight, hyperinsulinemia, and hepatic lipid accumulation. Moreover, vitamin D deficiency up-regulated the expression of uncoupling protein 3 (Ucp3) in white adipose tissue (WAT) and brown adipose tissue (BAT). The present study aimed to further investigate the effects of vitamin D and vitamin D receptor (Vdr) on Ucp1–3 (Ucps) expression in brown adipocyte and the mechanism involved in it. Rat primary brown adipocytes were separated and purified. The effects of the 1,25(OH)2D3 (1,25-dihydroxyvitamin D3; the hormonal form of vitamin D) and Vdr system on Ucps expression in brown adipocytes were investigated in basal condition and activated condition by isoproterenol (ISO) and triiodothyronine (T3). Ucps expression levels were significantly down-regulated by 1,25(OH)2D3 in the activated brown adipocyte. Vdr silencing reversed the down-regulation of Ucps by 1,25(OH)2D3, whereas Vdr overexpression strengthened the down-regulation effects. Hairless protein did express in brown adipocyte and was localized in cell nuclei. 1,25(OH)2D3 increased Hairless protein expression in the cell nuclei. Hairless (Hr) silencing notably elevated Ucps expression in activated condition induced by ISO and T3. Moreover, immunoprecipitation results revealed that Vdr could interact with Hairless, which might contribute to decreasing expression of Vdr target gene Ucps. These data suggest that vitamin D suppresses expression of Ucps in brown adipocyte in a Vdr-dependent manner and the corepressor Hairless protein probably plays a role in the down-regulation.

The hereditary aspect of obesity is a major focus of modern medical genetics. The genetic background is known to determine a higher-than-average prevalence of obesity in certain regions, like Oceania. There is evidence that dysfunction of brown adipose tissue (BAT) may be a risk factor for obesity and type 2 diabetes (T2D). A significant number of studies in the field focus on the UCP family. TheUcpgenes code for electron transport carriers. UCP1 (thermogenin) is the most abundant protein of the UCP superfamily and is expressed in BAT, contributing to its capability of generating heat. Single nucleotide polymorphisms (SNPs) ofUcp1–Ucp3were recently associated with risk of cardiometabolic diseases. This review covers the mainUcpSNPs A–3826G, A–1766G, A–112C, Met229Leu, Ala64Thr (Ucp1), Ala55Val, G–866A (Ucp2), and C–55 T (Ucp3), which may be associated with the development of obesity, disturbance in lipid metabolism, T2D, and cardiovascular diseases.

Background Bariatric surgery is well established as a treatment for obesity and associated complications. This procedure improves metabolic homeostasis through changes in energy expenditure. We hypothesized that sleeve gastrectomy (SG) improves metabolic homeostasis by modulating energy expenditure and enhancing thermogenesis through increasing the expression level of meteorin-like protein (METRNL) and fibronectin type III domain-containing protein 5 (FNDC5/Irisin) through uncoupling proteins 1/2/3 (UCP1, UCP2, and UCP3). Objectives To study the effect of SG on the levels of proteins involved in thermogenesis process. Setting Laboratory rats at Kuwait University. Methods Male Sprague-Dawley rats, aged 4 to 5 weeks, were divided into 2 groups, control (n = 11) and diet-induced obesity (DIO) (n = 22). The control group was fed regular rat chow ad libitum, whereas the DIO group was fed cafeteria diet “high-fat/carbohydrate diet” ad libitum. At 21 weeks, rats in the DIO group that weighed 20% more than the control group animals underwent surgery. These rats were randomly subdivided into Sham and SG operation groups. Gene expression was evaluated, and enzyme-linked immunosorbent assays were employed to assess the changes in gene and protein levels in tissue and circulation. Results The protein expression data revealed an increase in METRNL levels in the muscles and white adipose tissue of SG animals. METRNL level in circulation in SG animals was reduced compared with control and Sham rats. The level of Irisin increased in the muscle of SG animals compared with the control and Sham group animals; however, a decrease in Irisin level was observed in the white adipose tissue and brown adipose tissue of SG animals compared with controls. Gene expression analysis revealed decreased METRNL levels in muscle tissues in the SG group compared with the control group animals. Increased expression of FNDC5 (Irisin), UCP2, and UCP3 in the muscle tissue of SG animals was also observed. Furthermore, the levels of UCP1, UCP2, UCP3, and METRNL in the brown adipose tissue of SG animals were upregulated. No significant alteration in the gene expression of Irisin was observed in brown adipose tissue. Conclusions Sleeve gastrectomy induces weight loss through complex mechanisms that may include browning of fat.

Background: exercise conditions can affect the expression of genes. Our study investigated the effects of acute and chronic exercise on the expression of genes related to oxidative stress (Tfam,UCP2,UCP3 ) and immune system (IL-1α,IL-1β,IL-2,IL-8,IL12A,IL12B,TLR2,TLR4 ). Methods: was formed with 24 people: 12 healthy females and 12 healthy males. Maximal oxygen use capacities of the participants were determined by the Bruce test protocol at the beginning and end of the 8-week training program. After calculating their maximal oxygen use capacity, each participant was given a acute running exercise on the tread mill at the speed and incline that the participant would reach to his/her maxVO2 until exhausted. The same people was built to continuous runs (%50-70) for 8 weeks in a week, and two days of medium-term interval training program (%90-95). Peripheral blood samples were taken before and after acute exercise with immediately after chronic exercises. RNA isolation was performed using TRIzol Reagent from peripheral blood mononuclear cells. Gene expression was determined by Biomark Real-Time PCR (RT-PCR). Comparisons were performed by using two independent sample t-test and Mann-Whitney U for quantitative data and calculated gene expression values. The statistical significance level was taken as p

Skeletal muscle long non-coding RNAs (lncRNAs) were reported to be involved in the development of type 2 diabetes (T2D). However, little is known about the mechanism of skeletal muscle lncRNAs on hyperglycemia of diabetic Goto-Kakizaki (GK) rats at the age of 3 and 4 weeks. To elucidate this, we used RNA-sequencing to profile the skeletal muscle transcriptomes including lncRNAs and mRNAs, in diabetic GK and control Wistar rats at the age of 3 and 4 weeks. In total, there were 438 differentially expressed mRNAs (DEGs) and 401 differentially expressed lncRNAs (DELs) in skeletal muscle of 3-week-old GK rats compared with age-matched Wistar rats, and 1000 DEGs and 726 DELs between GK rats and Wistar rats at 4 weeks of age. The protein–protein interaction analysis of overlapping DEGs between 3 and 4 weeks, the correlation analysis of DELs and DEGs, as well as the prediction of target DEGs of DELs showed that these DEGs (Pdk4, Stc2, Il15, Fbxw7 and Ucp3) might play key roles in hyperglycemia, glucose intolerance, and increased fatty acid oxidation. Considering the corresponding co-expressed DELs with high correlation coefficients or targeted DELs of these DEGs, our study indicated that these dysregulated lncRNA-mRNA pairs (NONRATG017315.2-Pdk4, NONRATG003318.2-Stc2, NONRATG011882.2-Il15, NONRATG013497.2-Fbxw7, MSTRG.1662-Ucp3) might be related to above biological processes in GK rats at the age of 3 and 4 weeks. Our study could provide more comprehensive knowledge of mRNAs and lncRNAs in skeletal muscle of GK rats at 3 and 4 weeks of age. And our study may provide deeper understanding of the underlying mechanism in T2D of GK rats at the age of 3 and 4 weeks.

Alcohol consumption leads to the dysfunction of multiple organs including liver, heart, and skeletal muscle. Alcohol effects on insulin resistance in liver are well evidenced, whereas its effects in skeletal muscle remain controversial. Emerging evidence indicates that alcohol promotes adipose tissue dysfunction, which may induce organ dysregulation. We show that consumption of ethanol (EtOH) reduces the activation of 5′AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) as well as the protein of carnitine palmitoyltransferase 1 (CPT1) and glucose transporter type 4 (GLUT4) in C2C12 myotube. We observed that chronic EtOH consumption increases free fatty acid levels in plasma and triglyceride (TG) accumulation in skeletal muscle and that these increases induce insulin resistance and decrease glucose uptake. Hence, ethanol dysregulates metabolic factors and induces TG accumulation. We found peroxisome proliferator-activated receptor β/δ (PPARδ) activation recovers AMPK activation and increases carnitine-acylcarnitine translocase (CACT) protein. These effects may contribute to enhance mitochondrial activation via uncoupling protein 3 (UCP3) when fatty acids are used as a substrate, thus reduces EtOH-induced increases in TG levels in skeletal muscle. In addition, PPARδ activation recovered EtOH-induced loss of protein kinase B (AKT) phosphorylation at serine 473 via rapamycin-insensitive companion of mammalian target of rapamycin (Rictor) activation. Importantly, PPARδ activation enhanced mitochondrial uncoupling via UCP3. Taken together, the study shows PPARδ enhances fatty acid utilization and uncoupled respiration via UCP3 and protects against EtOH-induced lipotoxicity and insulin resistance in skeletal muscle.

MAP kinase-activated protein kinase-2 (MK2) is protein serine/threonine kinase activated by p38α/β. Herein we examined the cardiac phenotype of pan MK2-null (MK2-/-) mice. Survival curves for male MK2+/+ and MK2-/- mice did not differ (Mantel-Cox test, P = 0.580). At 12-weeks of age, MK2-/- mice exhibited normal systolic function along with signs of possible early diastolic dysfunction; however, ageing was not associated with an abnormal reduction in diastolic function. Both R-R interval and P-R segment durations were prolonged in MK2-deficient mice. However, heart rates normalized when isolated hearts were perfused ex vivo in working mode. Ca2+ transients evoked by field stimulation or caffeine were similar in ventricular myocytes from MK2+/+ and MK2-/- mice. MK2-/- mice had lower body temperature and an age-dependent reduction in body weight. mRNA levels of key metabolic genes, including Ppargc1a, Acadm, Lipe, and Ucp3 were increased in hearts from MK2-/- mice. For equivalent respiration rates, mitochondria from MK2-/- hearts showed a significant decrease in Ca2+-sensitivity to mitochondrial permeability transition pore (mPTP) opening. Finally, the pressure overload-induced increase in heart weight/tibia length and decrease in systolic function were attenuated in MK2-/- mice two weeks, but not eight weeks, after constriction of the transverse aorta. Collectively, these results implicate MK2 in (i) autonomic regulation of heart rate, (ii) cardiac mitochondrial function, and (iii) the early stages of myocardial remodeling in response to chronic pressure overload.

Objective Uncoupling protein 3 (UCP3) is a mitochondrial carrier related to fatty acid metabolism. Although gene variants of UCP3 are associated with human obesity, their contribution to increased adiposity remains unclear. This study investigated the impact that loss of UCP3 has on diet-induced obesity in rats. Methods Male UCP3 knockout rats (ucp3-/- ) and wild-type littermates (ucp3+/+ ) were fed a high-fat, high-carbohydrate Western diet for 21 weeks. Body composition was analyzed by EchoMRI. Whole-body insulin sensitivity and rates of tissue glucose uptake were determined by using hyperinsulinemic-euglycemic clamp. Changes in tissue physiology were interrogated by microscopy and RNA sequencing. Results Loss of UCP3 decreased fat mass gain, white adipocytes size, and systemic inflammation. The ucp3-/- rats also exhibited preserved insulin sensitivity and increased glucose uptake in interscapular brown adipose tissue (iBAT). Brown adipocytes from ucp3-/- rats were protected from cellular degeneration caused by lipid accumulation and from reactive oxygen species-induced protein sulfonation. Increased glutathione levels in iBAT from ucp3-/- rats were linked to upregulation of genes encoding enzymes from the transsulfuration pathway in that tissue. Conclusions Loss of UCP3 partially protects rats from diet-induced obesity. This phenotype is related to induction of a compensatory antioxidant mechanism and prevention of iBAT whitening.

BACKGROUND: Inorganic nitrate, abundant in leafy green vegetables and beetroot, is thought to have protective health benefits. Adherence to a Mediterranean diet reduces the incidence and severity of coronary artery disease, whereas supplementation with nitrate can improve submaximal exercise performance. Once ingested, oral commensal bacteria may reduce nitrate to nitrite, which may subsequently be reduced to nitric oxide during conditions of hypoxia and in the presence of "nitrite reductases" such as heme- and molybdenum-containing enzymes.OBJECTIVE: We aimed to explore the putative effects of inorganic nitrate and nitrite on mitochondrial function in skeletal muscle.METHODS: Mice were subjected to a nitrate/nitrite-depleted diet for 2 wk, then supplemented with sodium nitrate, sodium nitrite, or sodium chloride (1 g/L) in drinking water ad libitum for 7 d before killing. Skeletal muscle mitochondrial function and expression of uncoupling protein (UCP) 3, ADP/ATP carrier protein (AAC) 1 and AAC2, and pyruvate dehydrogenase (PDH) were assessed by respirometry and Western blotting. Studies were also undertaken in human skeletal muscle biopsies from a cohort of coronary artery bypass graft patients treated with either sodium nitrite (30-min infusion of 10 μmol/min) or vehicle [0.9% (wt:vol) saline] 24 h before surgery.RESULTS: Neither sodium nitrate nor sodium nitrite supplementation altered mitochondrial coupling efficiency in murine skeletal muscle, and expression of UCP3, AAC1, or AAC2, and PDH phosphorylation status did not differ between the nitrite and saline groups. Similar results were observed in human samples.CONCLUSIONS: Sodium nitrite failed to improve mitochondrial metabolic efficiency, rendering this mechanism implausible for the purported exercise benefits of dietary nitrate supplementation. This trial was registered at clinicaltrials.gov as NCT04001283.

Recently, we reported that bangle intake promotes exercise-induced effects such as reducing insulin resistance and non-esterified fatty acid levels and ameliorating the loss of autophagy function in rats fed high-fat diets. In the present study, we examined the physiological effects of cis-banglene on C2C12 skeletal muscle cells. cis-Banglene activated AMPK, an exercise mimic target. It also promoted glucose uptake (2-NBDG uptake) and mitochondrial biogenesis (Rho 123 uptake and mtDNA copy number) as well as increased the mRNA expression (real-time PCR) and secretion of IL-6 (ELISA), a myokine produced by exercising skeletal muscles. Furthermore, cis-banglene significantly increased the mRNA expression levels of PPARγ, PGC-1α, LPL, CD36, and UCP3. These findings are consistent with previously reported changes in mRNA expression levels in the muscles during exercise. Thus, cis-banglene is a candidate exercise mimetic for increasing mitochondrial biogenesis and glucose uptake by activating the IL-6/AMPK signaling pathway.

Angiotensin-converting enzyme (ACE) is expressed in human skeletal muscle. The ACE I/D polymorphism has been associated with athletic performance in some studies. Studies have suggested that the ACE I/D gene variant is associated with ACE enzyme content in serum, and there is an interaction between ACE and uncoupling proteins 2 and 3 (UCP2 and UCP3). However, no studies have explored the effect of ACE I/D on ACE, UCP2, and UCP3 protein content in human skeletal muscle. Utilizing the Gene SMART cohort ( n = 81), we investigated whether the ACE I/D gene variant is associated with ACE enzyme content in blood and ACE, UCP2, and UCP3 protein content in skeletal muscle at baseline and following a session of high-intensity interval exercise (HIIE). Using a stringent and robust statistical analyses, we found that the ACE I/D gene variant was associated with ACE enzyme content in blood ( P < 0.005) at baseline but not the ACE, UCP2, and UCP3 protein content in muscle at baseline. A single session of HIIE tended (0.005 < P < 0.05) to increase blood ACE content immediately postexercise, whereas muscle ACE protein content was lower 3 h after a single session of HIIE ( P < 0.005). Muscle UCP3 protein content decreased immediately after a single session of HIIE ( P < 0.005) and remained low 3 h postexercise. However, those changes in the muscle were not genotype dependent. In conclusion, The ACE I/D gene variant predicts ACE enzyme content in blood but not the ACE, UCP2, and UCP3 protein content of human skeletal muscle.NEW & NOTEWORTHY This paper describes the association between ACE I/D gene variant and ACE protein content in blood and ACE, UCP2, and UCP3 protein content in skeletal muscle at baseline and after exercise in a large cohort of healthy males. Our data suggest that ACE I/D is a strong predictor of blood ACE content but not muscle ACE content.

Fasting is often used for obesity correction but the &ldquo, refeeding syndrome&rdquo, limits its efficiency, and molecular mechanisms underlying metabolic response to different food availability are under investigation. Sex was shown to affect hormonal and metabolic reactions to fasting/refeeding. The aim of this study was to evaluate hormonal and transcriptional responses to fasting and refeeding in male and female C57Bl/6J mice. Sex asymmetry was observed both at the hormonal and transcriptional levels. Fasting (24 h) induced increase in hepatic Fgf21 gene expression, which was associated with elevation of plasma FGF21 and adiponectin levels, and the upregulation of expression of hepatic (Ppar&alpha, Cpt1&alpha, ) and muscle (Cpt1&beta, Ucp3) genes involved in fatty acid oxidation. These changes were more pronounced in females. Refeeding (6 h) evoked hyperinsulinemia and increased hepatic expression of gene related to lipogenesis (Fasn) only in males and hyperleptinemia and increase in Fgf21 gene expression in muscles and adipose tissues only in females. The results suggest that in mice, one of the molecular mechanisms underlying sex asymmetry in hepatic Ppar&alpha, muscle Cpt1&beta, and Ucp3 expression during fasting is hepatic Fgf21 expression, and the reason for sex asymmetry in hepatic Fasn expression during refeeding is male-specific hyperinsulinemia.

The aim of this study was to investigate the effects of excess leucine (Leu) vs. its metabolites α-ketoisocaproate (KIC) and β-hydroxy-β-methyl butyrate (HMB) on Leu metabolism, muscle fibre composition and muscle growth in growing pigs. Thirty-two pigs with a similar initial weight (9.55 ± 0.19 kg) were fed 1 of 4 diets for 45 days: basal diet, basal diet + 1.25% L-Leu, basal diet + 1.25% KIC-Ca, basal diet + 0.62% HMB-Ca. Results indicated that relative to the basal diet and HMB groups, Leu and KIC groups exhibited increased Leu concentrations and decreased concentrations of isoleucine, valine and EAAs in selected muscle (p < 0.05) and had lower mRNA levels of MyHC I and higher expression of MyHC IIx/IIb (p < 0.05), and there was no significant difference between the basal and HMB-supplemented groups. Moreover, the mRNA expression levels of AMPKα and UCP3 were higher but the myostatin mRNA levels were lower in the soleus muscle of the HMB group than those from other groups (p < 0.05). These findings demonstrated that doubling dietary Leu content exerted growth-depressing effects in growing pigs; dietary KIC supplementation induced muscular branched-chain amino acid imbalance and promoted muscle toward a more glycolytic phenotype; while dietary HMB supplementation promoted the generation of more oxidative muscle types and increased muscle growth specially in oxidative skeletal muscle, and these effects of HMB might be associated with the AMPKα-Sirt1-PGC-1α axis and mitochondrial biogenesis.

The real mechanisms of intensive exercise training-induced energy efficiency have not yet been well examined. Therefore, the aim of the present study was to investigate the effects of sprint interval training (SIT) on gene expression of uncoupling proteins (UCPs) and endothelial nitric oxide synthase (eNOS). For this purpose, 16 Albino Wistar rats (250–300 g) were randomly divided into equal groups of control and sprint training. The animals run on treadmill for 10 weeks, 5 days per week at intensity corresponding to 90–95% maximal oxygen consumption. The gene expression of UCP2, UCP3 and eNOS was analyzed by RT-PCR method in hearts. The data were analyzed by independent samples T test at P

BACKGROUND Revascularization is a successful therapeutic strategy for myocardial infarction. However, restoring coronary blood flow can lead to ischemia-reperfusion (I/R) injury. Low-dose 4-hydroxy-2-nonenal (HNE) therapy appears to play a key role in myocardial tolerance to I/R injury. We hypothesized that the positive effects of HNE on myocardial I/R injury may be UCP3-dependent. MATERIAL AND METHODS Adult male wild-type (WT) or UCP3 knockout (UCP3-/-) mice were pre-treated with the UCP inhibitor genipin or saline 1 h before ischemia and underwent 30-min coronary artery ligation followed by 24-h reperfusion. Mice were treated with intravenous HNE (4 mg/kg) or saline 5 min before reperfusion. Echocardiography was conducted to measure left ventricular end-diastolic posterior wall thickness (LVPWd), end-diastolic diameter (LVEDD), and fractional shortening (FS). Infarct size was measured by TTC staining. qRT-PCR and Western blotting were used to assess the expression of UCP3, UCP2, and the apoptosis markers cytochrome C and cleaved caspase-3. RESULTS HNE improved survival at 24 h post-MI in wild-type mice (p

Purpose The effects of a low rate (100 mGy/min) fractionated whole body gamma irradiation (FWBGI) at different doses were assessed using a real-time PCR technique on the expression of some target genes implicated in the development of type 2 diabetes mellitus in high-fat diet (HFD) Wistar rats. Method HFD Wistar rats were exposed to different doses (12, 24 and 48 Gy) divided into 24 fractions (three times a week for two months), thus, the daily doses were 0.5, 1, 2 Gy, respectively. Total RNA was extracted and the expression of target genes was measured in the four intestinal segments (duodenum, jejunum, ileum and colon). Results The pre-diabetic state already induced by HFD was found to be improved by irradiation exposure. This irradiation effect occurs mainly via altered anti-diabetic gene expressions (mRNA and protein levels) of the incretin glucagon-like peptide-1 (GLP-1) overall bowel segments except the colon which has its own specific response to irradiation exposure by the induction of the insulin receptor substrate 4 (IRS-4) and the uncoupling protein 3 (UCP3). Conclusions Results could be of great importance suggesting for the first time, a protective role for FWBGI on HFD animal models by increasing GLP-1 and UCP3 levels.

The effects of feeding behavior and diet composition, as well as their possible interactions, on daily (clock) gene expression rhythms have mainly been studied in the liver, and to a lesser degree in white adipose tissue (WAT), but hardly in other metabolic tissues such as skeletal muscle (SM) and brown adipose tissues (BAT). We therefore subjected male Wistar rats to a regular chow or free choice high-fat-high sugar (fcHFHS) diet in combination with time restricted feeding (TRF) to either the light or dark phase. In SM, all tested clock genes lost their rhythmic expression in the chow light fed group. In the fcHFHS light fed group rhythmic expression for some, but not all, clock genes was maintained, but shifted by several hours. In BAT the daily rhythmicity of clock genes was maintained for the light fed groups, but expression patterns were shifted as compared with ad libitum and dark fed groups, whilst the fcHFHS diet made the rhythmicity of clock genes become more pronounced. Most of the metabolic genes in BAT tissue tested did not show any rhythmic expression in either the chow or fcHFHS groups. In SM Pdk4 and Ucp3 were phase-shifted, but remained rhythmically expressed in the chow light fed groups. Rhythmic expression was lost for Ucp3 whilst on the fcHFHS diet during the light phase. In summary, both feeding at the wrong time of day and diet composition disturb the peripheral clocks in SM and BAT, but to different degrees and thereby result in a further desynchronization between metabolically active tissues such as SM, BAT, WAT and liver., Highlights • Both timing of feeding and diet composition affect clock genes in BAT and SM. • Light phase time-restricted feeding abolishes SM clock gene rhythms. • A fcHSHS diet strengthens rhythmic expression of several clock genes in BAT and SM. • Metabolic genes PDK4 and UCP1/3 are affected by both timing of feeding and diet. • Light phase time-restricted feeding causes desynchronization of BAT and SM clocks.

Background/Aims: Many clinical and experimental studies have shown that treatment with statins could prevent myocardial hypertrophy and remodeling induced by hypertension and myocardial infarction. But the molecular mechanism was not clear. We aimed to investigate the beneficial effects of atorvastatin on hypertension-induced myocardial hypertrophy and remodeling in spontaneously hypertensive rats (SHR) with the hope of revealing other potential mechanisms or target pathways to interpret the pleiotropic effects of atorvastatin on myocardial hypertrophy. Methods: The male and age-matched animals were randomly divided into three groups: control group (8 WKY), SHR (8 rats) and intervention group (8 SHR). The SHR in intervention group were administered by oral gavage with atorvastatin (suspension in distilled water, 10 mg/Kg once a day) for 6 weeks, and the other two groups were administered by gavage with equal quantity distilled water. Blood pressure of rats was measured every weeks using a standard tail cuff sphygmomanometer. Left ventricular (LV) dimensions were measured from short-axis views of LV under M-mode tracings using Doppler echocardiograph. Cardiomyocyte apoptosis was assessed by the TUNEL assay. The protein expression of C/EBPβ, PGC-1α and UCP3 were detected by immunohistochemistry or Western blot analysis. Results: At the age of 16 weeks, the mean arterial pressure of rats in three groups were 103.6±6.1, 151.8±12.5 and 159.1±6.2 mmHg respectively, and there wasn’t statistically significant difference between the SHR and intervention groups. Staining with Masson’s trichrome demonstrated that the increased interstitial fibrosis of LV and ventricular remodeling in the SHR group were attenuated by atorvastatin treatment. Echocardiography examination exhibited that SHR with atorvastatin treatment showed an LV wall thickness that was obviously lower than that of water-treated SHR. In hypertrophic myocardium, accompanied by increasing C/EBPβ expression and the percentage of TUNEL-positive cells, the expression of Bcl-2/Bax ratio, PGC-1α and UCP3 were reduced, all of which could be abrogated by treatment with atorvastatin for 6 weeks. Conclusion: This study further confirmed that atorvastatin could attenuate myocardial hypertrophy and remodeling in SHR by inhibiting apoptosis and reversing changes in mitochondrial metabolism. The C/EBPβ/PGC-1α/UCP3 signaling pathway might also be important for elucidating the beneficial pleiotropic effects of atorvastatin on myocardial hypertrophy.

Reduced mitochondrial capacity in skeletal muscle has been observed in obesity and type 2 diabetes. In humans, the aetiology of this abnormality is not well understood but the possibility that it is secondary to the stress of nutrient overload has been suggested. To test this hypothesis, we examined whether sustained overfeeding decreases skeletal muscle mitochondrial content or impairs function. Twenty-six healthy volunteers (21 men, 5 women, age 25.3 ± 4.5 years, BMI 25.5 ± 2.4 kg/m2) underwent a supervised protocol consisting of 8 weeks of high-fat overfeeding (40% over baseline energy requirements). Before and after overfeeding, we measured systemic fuel oxidation by indirect calorimetry and performed skeletal muscle biopsies to measure mitochondrial gene expression, content and function in vitro. Mitochondrial function in vivo was measured by 31P NMR spectroscopy. With overfeeding, volunteers gained 7.7 ± 1.8 kg (% change 9.8 ± 2.3). Overfeeding increased fasting NEFA, LDL-cholesterol and insulin concentrations. Indirect calorimetry showed a shift towards greater reliance on lipid oxidation. In skeletal muscle tissue, overfeeding increased ceramide content, lipid droplet content and perilipin-2 mRNA expression. Phosphorylation of AMP-activated protein kinase was decreased. Overfeeding increased mRNA expression of certain genes coding for mitochondrial proteins (CS, OGDH, CPT1B, UCP3, ANT1). Despite the stress of nutrient overload, mitochondrial content and mitochondrial respiration in muscle did not change after overfeeding. Similarly, overfeeding had no effect on either the emission of reactive oxygen species or on mitochondrial function in vivo. Skeletal muscle mitochondria are significantly resilient to nutrient overload. The lower skeletal muscle mitochondrial oxidative capacity in human obesity is likely to be caused by reasons other than nutrient overload per se. ClinicalTrials.gov NCT01672632.

Apelin, a ligand for G protein-coupled APJ receptor, is a peptide hormone. Although apelin and APJ receptors are determined in hypothalamus and thyroid gland its role in the hypothalamus–pituitary–thyroid (HPT) axis and mechanism of action on energy metabolism is not clear. This suggests that apelin may play a role in the HPT axis and energy metabolism. This study was designed to determine possible effects of centrally administered apelin-13 on the HPT axis and energy metabolism. A total of 40 adult male Sprague Dawley rats were divided into four groups (n = 10 each group). Intact rats served as control group while the sham group received vehicle of apelin. Apelin-13 was injected intracerebroventricularly at the doses of 1 and 10 nmol, for 7 days in the rats in the experimental group. At the end of the experimental protocol, animals were decapitated and brain, blood, white and brown adipose tissues samples were collected. There was no significant difference between the groups in terms of hypothalamic TRH mRNA levels. Serum TSH levels were significantly higher in all groups compared to the control group (p

Metabolic disturbance and mitochondrial dysfunction are a hallmark of diabetic cardiomyopathy (DC). Resistance exercise (RE) not only enhances the condition of healthy individuals but could also improve the status of those with disease. However, the beneficial effects of RE in the prevention of DC and mitochondrial dysfunction are uncertain. Therefore, this study investigated whether RE attenuates DC by improving mitochondrial function using an in vivo rat model of diabetes. Fourteen Otsuka Long-Evans Tokushima Fatty rats were assigned to sedentary control (SC, n = 7) and RE (n = 7) groups at 28 weeks of age. Long-Evans Tokushima Otsuka rats were used as the non-diabetic control. The RE rats were trained by 20 repetitions of climbing a ladder 5 days per week. RE rats exhibited higher glucose uptake and lower lipid profiles, indicating changes in energy metabolism. RE rats significantly increased the ejection fraction and fractional shortening compared with the SC rats. Isolated mitochondria in RE rats showed increase in mitochondrial numbers, which were accompanied by higher expression of mitochondrial biogenesis proteins such as proliferator-activated receptor-γ coactivator-1α and TFAM. Moreover, RE rats reduced proton leakage and reactive oxygen species production, with higher membrane potential. These results were accompanied by higher superoxide dismutase 2 and lower uncoupling protein 2 (UCP2) and UCP3 levels in RE rats. These data suggest that RE is effective at ameliorating DC by improving mitochondrial function, which may contribute to the maintenance of diabetic cardiac contractility.

Hepatic mitochondrial function, APOC-III, and LPL are potential targets for triglyceride (TG)-lowering drugs. After 3 weeks of dietary treatment with the compound 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA), the hepatic mitochondrial FA oxidation increased more than 5-fold in male Wistar rats. Gene expression analysis in liver showed significant downregulation of APOC-III and upregulation of LPL and the VLDL receptor. This led to lower hepatic (53%) and plasma (73%) TG levels. Concomitantly, liver-specific biomarkers related to mitochondrial biogenesis and function (mitochondrial DNA, citrate synthase activity, and cytochrome c and TFAM gene expression) were elevated. Interestingly, 1-triple TTA lowered plasma acetylcarnitine levels, whereas the concentration of β-hydroxybutyrate was increased. The hepatic energy state was reduced in 1-triple TTA-treated rats, as reflected by increased AMP/ATP and decreased ATP/ADP ratios, whereas the energy state remained unchanged in muscle and heart. The 1-triple TTA administration induced gene expression of uncoupling protein (UCP)2 and UCP3 in liver. In conclusion, the 1-triple TTA-mediated clearance of blood TG may result from lowered APOC-III production, increased hepatic LPL gene expression, mitochondrial FA oxidation, and (re)uptake of VLDL facilitating drainage of FAs to the liver for β-oxidation and production of ketone bodies as extrahepatic fuel. The possibility that UCP2 and UCP3 mediate a moderate degree of mitochondrial uncoupling should be considered.