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1.
Biol Res ; 53(1): 45, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023658

RESUMO

BACKGROUND: Skeletal muscle has an important role in regulating whole-body energy homeostasis, and energy production depends on the efficient function of mitochondria. We demonstrated previously that AT-rich interactive domain 5b (Arid5b) knockout (Arid5b-/-) mice were lean and resistant to high-fat diet (HFD)-induced obesity. While a potential role of Arid5b in energy metabolism has been suggested in adipocytes and hepatocytes, the role of Arid5b in skeletal muscle metabolism has not been studied. Therefore, we investigated whether energy metabolism is altered in Arid5b-/- skeletal muscle. RESULTS: Arid5b-/- skeletal muscles showed increased basal glucose uptake, glycogen content, glucose oxidation and ATP content. Additionally, glucose clearance and oxygen consumption were upregulated in Arid5b-/- mice. The expression of glucose transporter 1 (GLUT1) and 4 (GLUT4) in the gastrocnemius (GC) muscle remained unchanged. Intriguingly, the expression of TBC domain family member 1 (TBC1D1), which negatively regulates GLUT4 translocation to the plasma membrane, was suppressed in Arid5b-/- skeletal muscle. Coimmunofluorescence staining of the GC muscle sections for GLUT4 and dystrophin revealed increased GLUT4 localization at the plasma membrane in Arid5b-/- muscle. CONCLUSIONS: The current study showed that the knockout of Arid5b enhanced glucose metabolism through the downregulation of TBC1D1 and increased GLUT4 membrane translocation in skeletal muscle.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas Ativadoras de GTPase/genética , Glucose , Músculo Esquelético , Fatores de Transcrição/genética , Animais , Transporte Biológico , Regulação para Baixo , Glucose/metabolismo , Transportador de Glucose Tipo 1/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Camundongos , Camundongos Knockout , Músculo Esquelético/metabolismo
2.
J Oral Sci ; 62(4): 423-426, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32863319

RESUMO

PURPOSE: Diabetes causes hyperglycemic disorders due to insufficient activity of insulin, and it also increases blood glucose level. Recent studies have reported the relationship between diabetes and periodontal disease. Periodontitis is advanced by inflammatory cytokines stimulated with LPS. The purpose of this study was to investigate the effects of hyperglycemia on the expression of inflammatory cytokines induced by LPS in osteoblasts. METHODS: Cells were cultured for 7 and 14 days in the presence or absence of LPS and glucose. The expression mRNA level of IL-6, RANKL and OCN was determined using real-time PCR. The protein expression of IL-6 and RANKL was also measured using ELISA. RESULTS: LPS and glucose increased the mRNA expression of IL-6, coupled with a decrease in the mRNA expression of OCN, which is associated with IL-6 and glucose. It also increased the protein expression of IL-6 compared to LPS. However, LPS+Glucose did not affect the mRNA and protein expression of RANKL. Furthermore, GLUT4 inhibitor, WZB117, blocked the stimulatory effect of glucose on LPS-induced IL-6 mRNA expression. WZB117 did not affect LPS-reduced OCN mRNA expression. CONCLUSION: These results suggest that high glucose levels increase LPS-induced IL-6 expression mediated by GLUT4.


Assuntos
Transportador de Glucose Tipo 4/fisiologia , Interleucina-6 , Lipopolissacarídeos , Glucose , Proteínas Facilitadoras de Transporte de Glucose , Interleucina-6/metabolismo , Osteoblastos/metabolismo
3.
Acta Diabetol ; 57(11): 1383-1393, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32647998

RESUMO

AIMS: Steroid diabetes mellitus (SDM) is a metabolic syndrome caused by an increase in glucocorticoids, and its pathogenesis is unclear. 18F-FDG PET/CT can reflect the glucose metabolism of tissues and organs under living conditions. Here, PET/CT imaging of SDM and type 2 diabetes mellitus (T2DM) rats was used to visualize changes in glucose metabolism in the main glucose metabolizing organs and investigate the pathogenesis of SDM. METHODS: SDM and T2DM rat models were established. During this time, PET/CT imaging was used to measure the %ID/g value of skeletal muscle and liver to evaluate glucose uptake. The pancreatic, skeletal muscle and liver were analyzed by immunohistochemistry. RESULTS: SDM rats showed increased fasting blood glucose and insulin levels, hyperplasia of islet α and ß cells, increased FDG uptake in skeletal muscle accompanied by an up-regulation of PI3Kp85α, IRS-1, and GLUT4, no significant changes in liver uptake, and that glycogen storage in the liver and skeletal muscle increased. T2DM rats showed atrophy of pancreatic islet ß cells and decreased insulin levels, significantly reduced FDG uptake and glycogen storage in skeletal muscle and liver. CONCLUSIONS: The pathogenesis of SDM is different from that of T2DM. The increased glucose metabolism of skeletal muscle may be related to the increased compensatory secretion of insulin. Glucocorticoids promote the proliferation of islet α cells and cause an increase in gluconeogenesis in the liver, which may cause increased blood glucose.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico por imagem , Diabetes Mellitus/diagnóstico por imagem , Animais , Glicemia/metabolismo , Diabetes Mellitus/sangue , Diabetes Mellitus Tipo 2/sangue , Jejum/sangue , Fluordesoxiglucose F18/administração & dosagem , Glucocorticoides/metabolismo , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Glicogênio/metabolismo , Humanos , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/metabolismo , Fígado/diagnóstico por imagem , Fígado/metabolismo , Masculino , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/metabolismo , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Ratos , Ratos Wistar
4.
Am J Chin Med ; 48(5): 1073-1090, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32668968

RESUMO

Pro-inflammatory cytokines interfere with blood glucose homeostasis, which leads to hyperglycemia. Andrographis paniculata (AP) has been shown to possess anti-inflammatory activity and to reduce blood glucose levels in diabetes. The two major bioactive diterpenoids in AP, andrographolide (AND) and 14-deoxy-11,12-didehydroandrographolide (deAND), have potent anti-inflammatory activity. We studied whether APE (an ethanolic extract of AP), AND, and deAND could improve a high-fat diet (HFD)-induced hyperglycemia in vivo and TNF[Formula: see text]-induced impairment of insulin signaling in vitro. Male C57BL/6JNarl mice were fed a normal diet (ND) or the HFD, and the fatty mice were treated with APE, deAND, or AND for 16 weeks. 3T3-L1 cells were used to study the underlying mechanisms by which APE, deAND, or AND attenuated TNF[Formula: see text]-induced insulin resistance. The HFD significantly induced obesity, hyperglycemia, insulin resistance, and inflammation, whereas APE and deAND significantly ameliorated HFD-induced obesity, hyperglycemia, insulin resistance, and TNF[Formula: see text] production. The HFD significantly impaired insulin signaling by decreasing the protein expression of p-IRS1 tyr632 and p-AKT ser473, as well as the membrane translocation of GLUT4 in response to insulin stimulation in epididymal adipose tissue. HFD-impaired the membrane translocation of GLUT4 was significantly reversed by deAND and APE. In addition, deAND and APE markedly reversed the detrimental effect of TNF[Formula: see text] on the insulin signaling pathway and glucose uptake in 3T3-L1 cells. Despite no significant positive effect on p-AS160, a trend for recovery by deAND and APE was observed. These results suggest that deAND and APE protect against HFD-induced insulin resistance by ameliorating inflammation-driven impairment of insulin sensitivity.


Assuntos
Andrographis/química , Dieta Hiperlipídica/efeitos adversos , Resistência à Insulina , Obesidade/metabolismo , Extratos Vegetais/farmacologia , Células 3T3 , Animais , Transportador de Glucose Tipo 4/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/tratamento farmacológico , Obesidade/etiologia , Fitoterapia , Extratos Vegetais/uso terapêutico , Fator de Necrose Tumoral alfa/metabolismo
5.
Chem Biol Interact ; 330: 109198, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32692981

RESUMO

Quercetin 3-O-beta-d-glucopyranoside (isoquercetin) is one of the most frequent metabolites of the Passiflora ligularis Juss. The purpose of this study was to investigate the effect of the aqueous extract and ethanol fraction from P. ligularis Juss leaves on glycaemia and the mechanism of action of isoquercetin on glucose uptake. In the glucose tolerance test, the aqueous extract and ethanol fraction from P. ligularis Juss (125 mg/kg to 500 mg/kg o. g.) reduced glycaemia and increased the hepatic and muscular glycogen content. Phytochemical analysis evidenced the dominant presence of isoquercetin in the extract and fraction from leaves of P. ligularis Juss. Isoquercetin mediates the stimulatory effect on glucose uptake independent of insulin receptor activation but, involve PI3K, MAPK, MEK/ERK pathways and de novo protein synthesis to GLUT-4 translocation. Overall findings revealed that isoquercetin and aqueous extract and ethanol fraction of P. ligularis Juss leaves might be a promising functional food or medicine for the treatment or prevention of diabetes.


Assuntos
Glucose/farmacocinética , Músculo Esquelético/metabolismo , Passiflora/química , Quercetina/análogos & derivados , Animais , Transporte Biológico , Diabetes Mellitus/prevenção & controle , Transportador de Glucose Tipo 4/metabolismo , Compostos Fitoquímicos/análise , Extratos Vegetais/química , Folhas de Planta/química , Quercetina/isolamento & purificação , Quercetina/farmacologia , Ratos
6.
Zhongguo Ying Yong Sheng Li Xue Za Zhi ; 36(1): 12-16, 2020 Jan 28.
Artigo em Chinês | MEDLINE | ID: mdl-32476367

RESUMO

OBJECTIVE: To study the effects of acute and chronic exercise on phosphatidylinositol 3-hydroxy kinase(PI3K)/protein kinase B(AKT)/glucose transporter 4(GLUT4)signaling pathway in adipose tissue of rats with type 2 diabetes mellitus (T2DM) induced by high-fat diet and low-dose streptozotocin (STZ). METHODS: A total of 52 SD male rats aged 15 months were randomly divided into normal control group (13) and high-fat group (39), and fed normal and high fat diets. After 8 weeks, the body weight of the high-fat group was higher 20% than that of the normal control group. After a small dose of STZ, the blood glucose level was >16.7 mmol/l, and the model was successfully established. The diabetic model group was randomly divided into a diabetic control group (DC, n=13), a diabetic chronic exercise group (DCE, n=13), and a diabetic acute exercise group (DAE, n=13). The DCE group underwent an 8-week swimming exercise and the DAE group performed a one-time swimming exercise. Blood lipids, blood glucose and serum insulin levels were measured, and the contents of fat PI3K, AKT and GLUT4 proteins were determined by Western blot method. RESULTS: The levels of body weight, blood lipids, blood glucose and insulin in the diabetic group were significantly higher than those in the normal control group (P<0.01); high density liptein cholesterol(HDL-C) levels were decreased (P<0.05), and the expressions of PI3K, AKT and GLUT4 protein in adipose tissue were decreased (P<0.01). After 8 weeks of swimming training, the levels of body weight, blood lipids, blood glucose and insulin all were decreased significantly (P<0.01); while the level of HDL-C was increased (P<0.05), and the expressions of PI3K, AKT and GLUT4 protein were increased (P<0.01). After acute exercise, the levels of blood lipids, blood glucose and insulin were decreased (P<0.05); the level of HDL-C was increased (P<0.05), and the expression levels of fat PI3K, AKT and GLUT4 were increased significantly (P<0.05). CONCLUSION: ①High fat diet combined with low-dose STZ induced damage to the PI3K/AKT pathway in adipose tissue of T2DM rats reduced insulin sensitivity. ②Acute and chronic aerobic exercise can improve the disorder of glucose and lipid metabolism through PI3K/AKT pathway, and the chronic exercise is better than acute exercise.


Assuntos
Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 2/terapia , Resistência à Insulina , Condicionamento Físico Animal , Transdução de Sinais , Animais , Glicemia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Insulina/sangue , Lipídeos/sangue , Masculino , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Sprague-Dawley
7.
Exerc Sport Sci Rev ; 48(3): 110-118, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32568924

RESUMO

The glucose transporter GLUT4 is critical for skeletal muscle glucose uptake in response to insulin and muscle contraction/exercise. Exercise increases GLUT4 translocation to the sarcolemma and t-tubule and, over the longer term, total GLUT4 protein content. Here, we review key aspects of GLUT4 biology in relation to exercise, with a focus on exercise-induced GLUT4 translocation, postexercise metabolism and muscle insulin sensitivity, and exercise effects on GLUT4 expression.


Assuntos
Exercício Físico/fisiologia , Transportador de Glucose Tipo 4/metabolismo , Músculo Esquelético/metabolismo , Animais , Glucose/metabolismo , Transportador de Glucose Tipo 4/genética , Humanos , Resistência à Insulina/fisiologia , Contração Muscular/fisiologia , Transporte Proteico , Sarcolema/metabolismo , Transcrição Genética
8.
Chemosphere ; 253: 126772, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32464760

RESUMO

Zeranol is an approved but controversial growth-promoting agent for livestock in North America. It is a mycotoxin metabolite secreted by the Fusarium family fungi. The regulatory bodies in this region have established the acceptable daily intake and exposure below the level would not significantly increase the health risk for humans. However, their European counterparts have yet to establish an acceptable level and do not permit the use of this agent in farm animals. Given the growth-promoting ability of zeranol, its effect on energy metabolism was investigated in the current study. Our results indicated that zeranol could induce glucose transporter type 4 (GLUT4) expression in 3T3 L1 cells at 10 µM and initiate the translocation of the glucose transporter to the membrane as assayed by confocal microscopy. The translocation was likely triggered by the increase of GLUT4 and p-Akt. The insulin signal transduction pathway of glucose translocation was analyzed by Western blot analysis. Since no increase in the phosphorylated insulin receptor substrate in zeranol-treated cells was evidenced, the increased p-Akt and GLUT4 amount should be the mechanism dictating the GLUT4 translocation. In summary, this study showed that zeranol could perturb glucose metabolism in differentiated 3T3 L1 adipocytes. Determining the growth-promoting mechanism is crucial to uncover an accepted alternative to the general public.


Assuntos
Transportador de Glucose Tipo 4/metabolismo , Reguladores de Crescimento de Planta/toxicidade , Zeranol/toxicidade , Células 3T3-L1 , Adipócitos , Animais , Antígenos CD , Metabolismo dos Carboidratos , Glucose/metabolismo , Insulina/metabolismo , Gado , Camundongos , América do Norte , Fosforilação , Receptor de Insulina/metabolismo , Transdução de Sinais/efeitos dos fármacos
9.
Clin Sci (Lond) ; 134(10): 1167-1180, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32458968

RESUMO

In the present study, we evaluated the metabolic effects of green tea polyphenols (GTPs) in high-fat diet (HFD) fed Zucker fatty (ZF) rats, in particular the effects of GTP on skeletal muscle insulin sensitivity. Body weight, visceral fat, glucose tolerance, lipid profiles and whole-body insulin sensitivity were measured in HFD-fed ZF rats after 8-week-treatment with GTP (200 mg/kg of body weight) or saline (5 ml/kg of body weight). Zucker lean rats were studied as controls. Ex vivo insulin-mediated muscle glucose uptake was assessed. Immunoblotting was used to evaluate the expression of key insulin signalling proteins in skeletal muscle. GTP treatment attenuated weight gain (P<0.05) and visceral fat accumulation (27.6%, P<0.05), and significantly reduced fasting serum glucose (P<0.05) and insulin (P<0.01) levels. Homoeostasis model assessment of insulin resistance (HOMA-IR), a measure of insulin resistance, was lower (P<0.01) in GTP-treated animals compared with ZF controls. Moreover, insulin-stimulated glucose uptake by isolated soleus muscle was increased (P<0.05) in GTP-ZF rats compared with ZF-controls. GTP treatment attenuated the accumulation of ectopic lipids (triacyl- and diacyl-glycerols), enhanced the expression and translocation of glucose transporter-4, and decreased pSer612IRS-1 and increased pSer473Akt2 expression in skeletal muscle. These molecular changes were also associated with significantly decreased activation of the inhibitory (muscle-specific) protein kinase (PKC) isoform, PKC-θ. Taken together, the present study has shown that regular ingestion of GTP exerts a number of favourable metabolic and molecular effects in an established animal model of obesity and insulin resistance. The benefits of GTP are mediated in part by inhibiting PKC-θ and improving muscle insulin sensitivity.


Assuntos
Resistência à Insulina , Insulina/metabolismo , Músculo Esquelético/metabolismo , Polifenóis/farmacologia , Transdução de Sinais , Chá/química , Adiposidade/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Glucose/metabolismo , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 4/metabolismo , Gordura Intra-Abdominal/efeitos dos fármacos , Gordura Intra-Abdominal/metabolismo , Isoenzimas/metabolismo , Masculino , Proteínas Musculares/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Fosforilação/efeitos dos fármacos , Proteína Quinase C/metabolismo , Transporte Proteico/efeitos dos fármacos , Ratos Zucker
10.
Am J Physiol Endocrinol Metab ; 318(6): E943-E955, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32369414

RESUMO

Myokines, such as irisin, have been purported to exert physiological effects on skeletal muscle in an autocrine/paracrine fashion. In this study, we aimed to investigate the mechanistic role of in vivo fibronectin type III domain-containing 5 (Fndc5)/irisin upregulation in muscle. Overexpression (OE) of Fndc5 in rat hindlimb muscle was achieved by in vivo electrotransfer, i.e., bilateral injections of Fndc5 harboring vectors for OE rats (n = 8) and empty vector for control rats (n = 8). Seven days later, a bolus of D2O (7.2 mL/kg) was administered via oral gavage to quantify muscle protein synthesis. After an overnight fast, on day 9, 2-deoxy-d-glucose-6-phosphate (2-DG6P; 6 mg/kg) was provided during an intraperitoneal glucose tolerance test (2 g/kg) to assess glucose handling. Animals were euthanized, musculus tibialis cranialis muscles and subcutaneous fat (inguinal) were harvested, and metabolic and molecular effects were evaluated. Muscle Fndc5 mRNA increased with OE (~2-fold; P = 0.014), leading to increased circulating irisin (1.5 ± 0.9 to 3.5 ± 1.2 ng/mL; P = 0.049). OE had no effect on protein anabolism or mitochondrial biogenesis; however, muscle glycogen was increased, along with glycogen synthase 1 gene expression (P = 0.04 and 0.02, respectively). In addition to an increase in glycogen synthase activation in OE (P = 0.03), there was a tendency toward increased glucose transporter 4 protein (P = 0.09). However, glucose uptake (accumulation of 2-DG6P) was identical. Irisin elicited no endocrine effect on mitochondrial biogenesis or uncoupling proteins in white adipose tissue. Hindlimb overexpression led to physiological increases in Fndc5/irisin. However, our data indicate limited short-term impacts of irisin in relation to muscle anabolism, mitochondrial biogenesis, glucose uptake, or adipose remodeling.


Assuntos
Fibronectinas/genética , Músculo Esquelético/metabolismo , Gordura Subcutânea/metabolismo , Animais , Desoxiglucose/metabolismo , Óxido de Deutério , Eletroporação , Fibronectinas/metabolismo , Expressão Gênica , Glucose/metabolismo , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 4/genética , Glucose-6-Fosfato/análogos & derivados , Glucose-6-Fosfato/metabolismo , Glicogênio/metabolismo , Glicogênio Sintase/genética , Glicogênio Sintase/metabolismo , Membro Posterior , Masculino , Proteínas de Desacoplamento Mitocondrial/genética , Biogênese de Organelas , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , Ratos
11.
Diabetes ; 69(8): 1636-1649, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32439824

RESUMO

Insulin resistance due to overnutrition places a burden on energy-producing pathways in skeletal muscle (SkM). Nevertheless, energy state is not compromised. The hypothesis that the energy sensor AMPK is necessary to offset the metabolic burden of overnutrition was tested using chow-fed and high-fat (HF)-fed SkM-specific AMPKα1α2 knockout (mdKO) mice and AMPKα1α2lox/lox littermates (wild-type [WT]). Lean mdKO and WT mice were phenotypically similar. HF-fed mice were equally obese and maintained lean mass regardless of genotype. Results did not support the hypothesis that AMPK is protective during overnutrition. Paradoxically, mdKO mice were more insulin sensitive. Insulin-stimulated SkM glucose uptake was approximately twofold greater in mdKO mice in vivo. Furthermore, insulin signaling, SkM GLUT4 translocation, hexokinase activity, and glycolysis were increased. AMPK and insulin signaling intersect at mammalian target of rapamycin (mTOR), a critical node for cell proliferation and survival. Basal mTOR activation was reduced by 50% in HF-fed mdKO mice, but was normalized by insulin stimulation. Mitochondrial function was impaired in mdKO mice, but energy charge was preserved by AMP deamination. Results show a surprising reciprocity between SkM AMPK signaling and insulin action that manifests with diet-induced obesity, as insulin action is preserved to protect fundamental energetic processes in the muscle.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Insulina/metabolismo , Músculo Esquelético/metabolismo , Animais , Composição Corporal/fisiologia , Peso Corporal/fisiologia , Transportador de Glucose Tipo 4/metabolismo , Hexoquinase/metabolismo , Humanos , Resistência à Insulina/fisiologia , Camundongos , Camundongos Knockout , Camundongos Obesos , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
12.
Chem Biol Interact ; 324: 109093, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32298659

RESUMO

Polycystic Ovary Syndrome (PCOS), as a common endocrine disorder is accompanied by hyperandrogenism, insulin resistance, ovulation problems, and infertility. Various types of off-label drugs like metformin have been used for the management of targeted problems caused by PCOS such as insulin resistance and hyperandrogenism. Nicotinamide (NAM) acts as a substrate of visfatin and Nicotinamide N-Methyltransferase (NNMT) leading to the generation of Nicotinamide Adenine Dinucleotide (NAD) and N1-Methylnicotinamide (MNAM), respectively. MNAM is known as an anti-inflammatory, anti-thrombosis, and anti-diabetic agent. In this study, the effects of NAM and MNAM on metabolic and endocrine abnormalities were evaluated in the adipose and ovarian tissues of a letrozole-induced rat model of PCOS. Our results showed that MNAM and NAM reversed abnormal estrous cycle and reduced the serum testosterone levels and CYP17A1 gene expression. Furthermore, all therapeutic factors improved HOMA-IR after treatment and NAM significantly increased the expression of GLUT4 and decreased the gene expression of visfatin. Also, MNAM diminished the gene expression of visfatin and resistin. It is noteworthy that all the therapeutic factors successfully activated the AMPK. In summary, this study is the first study reported beneficial effects of NAM and MNAM on the treatment of PCOS. Additionally, the alleviative effects of our therapeutic factors may be partially mediated by the AMPK-dependent manner due to the contribution of the AMPK in the expression of CYP17A1, visfatin, resistin, and GLUT4. Although more studies are required to unravel the exact mode of actions of MNAM and NAM in the PCOS, the findings of the current study shed light on an urgent need for discovering novel therapeutic pharmaceuticals regarding the treatment of PCOS.


Assuntos
Tecido Adiposo/efeitos dos fármacos , Niacinamida/análogos & derivados , Niacinamida/uso terapêutico , Ovário/efeitos dos fármacos , Síndrome do Ovário Policístico/tratamento farmacológico , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Citocinas/genética , Citocinas/metabolismo , Ciclo Estral/efeitos dos fármacos , Feminino , Expressão Gênica/efeitos dos fármacos , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Hiperandrogenismo/tratamento farmacológico , Hormônio Luteinizante/metabolismo , Metformina/uso terapêutico , Nicotinamida Fosforribosiltransferase/genética , Nicotinamida Fosforribosiltransferase/metabolismo , Ratos Wistar , Resistina/genética , Resistina/metabolismo , Esteroide 17-alfa-Hidroxilase/genética , Esteroide 17-alfa-Hidroxilase/metabolismo , Testosterona/metabolismo
13.
Int J Mol Sci ; 21(6)2020 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-32245267

RESUMO

As emerging evidence suggesting neurodegenerative diseases and metabolic diseases have common pathogenesis, we hypothesized that the neurite outgrowth-controlling collapsin response mediator protein 2 (CRMP2) was involved in energy homeostasis. Therefore, putative roles of CRMP2 in adipocyte differentiation (adipogenesis) and lipid metabolism were explored and addressed in this study. CRMP2 expression profiles were in vitro and in vivo characterized during adipogenic process of 3T3-L1 pre-adipocytes and diet-induced obese (DIO) mice, respectively. Effects of CRMP2 on lipid metabolism and deposits were also analyzed. Our data revealed that CRMP2 expression pattern was coupled with adipogenic stages. CRMP2 overexpression inhibited cell proliferation at MCE phase, and significantly reduced lipid contents by down-regulating adipogenesis-driving transcription factors and lipid-synthesizing enzymes. Interestingly, GLUT4 translocation and the lipid droplets fusion were disturbed in CRMP2-silencing cells by affecting actin polymerization. Moreover, adipose CRMP2 was significantly increased in DIO mice, indicating CRMP2 is associated with obesity. Accordingly, CRMP2 exerts multiple functions in adipogenesis and lipid deposits through mediating cell proliferation, glucose/lipid metabolism and cytoskeleton dynamics. The present study identifies novel roles of CRMP2 in mediating adipogenesis and possible implication in metabolic disorders, as well as provides molecular evidence supporting the link of pathogenesis between neurodegenerative diseases and metabolic abnormalities.


Assuntos
Adipócitos/metabolismo , Citoesqueleto/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Metabolismo dos Lipídeos/genética , Proteínas do Tecido Nervoso/metabolismo , Obesidade/metabolismo , Células 3T3-L1 , Actinas/metabolismo , Adipócitos/citologia , Adipogenia/genética , Animais , Proliferação de Células/genética , Dieta Hiperlipídica , Técnicas de Silenciamento de Genes , Inativação Gênica , Glucose/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/genética , Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Obesidade/genética , RNA Interferente Pequeno , Transdução de Sinais/genética , Regulação para Cima
14.
Arch Biochem Biophys ; 686: 108365, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315651

RESUMO

Pelargonidin is a natural compound that exists widely in fruits, and exerts antioxidant, anti-atherosclerotic, anti-inflammatory, anti-hyperglycemic, and anti-diabetic activities. However, there have not been any studies concerning its anti-obesity potential to date. Therefore, we evaluated the anti-obesity potential of pelargonidin via inhibition of adipogenesis in 3T3-L1 cells. The cellular oil droplet content was decreased to 68.14%, 56.75%, and 48.39% and triglyceride accumulation decreased to 74.53%, 61.54%, and 47.86% after incubation with 5 µM, 10 µM, and 20 µM pelargonidin, respectively, when compared with DMSO group. Furthermore, pelargonidin treatment led to decrease in glucose consumption. Western blot assay illustrated that the expression of PPAR-γ was suppressed to 63.25%, 47.52%, and 21.23% after incubation with 5 µM, 10 µM, and 20 µM pelargonidin when compared with DMSO group. Then, we measured the expression of some target proteins of PPAR-γ, and found that pelargonidin decreased the expressions of HMGCR, LPL, Glut4, and A-FABP. Besides, the result of Luciferase Reporter Assay indicated that pelargonidin inhibited PPAR-γ transcription activity. These results indicated that pelargonidin exerts anti-adipogenic activity in 3T3-L1 cells through inhibition of PPAR-γ signaling pathway, and pelargonidin could be used as a potential anti-obesity agent.


Assuntos
Adipogenia/efeitos dos fármacos , Antocianinas/farmacologia , Fármacos Antiobesidade/farmacologia , PPAR gama/metabolismo , Células 3T3-L1 , Animais , Antocianinas/metabolismo , Fármacos Antiobesidade/metabolismo , Regulação para Baixo/efeitos dos fármacos , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Lipase Lipoproteica/genética , Lipase Lipoproteica/metabolismo , Camundongos , Triglicerídeos/genética , Triglicerídeos/metabolismo
15.
Nutrients ; 12(4)2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32230718

RESUMO

Insulin resistance, the hallmark of type 2 diabetes mellitus (T2DM), is linked to hyperinsulinemia, which develops to counterbalance initial peripheral hormone resistance. Studies indicate that chronically elevated levels of insulin lead to skeletal muscle insulin resistance by deregulating steps within the insulin signaling cascade. The polyphenol resveratrol (RSV) has been shown to have antidiabetic properties in vitro and in vivo. In the present study, we examined the effect of RSV on high insulin (HI)-induced insulin resistance in skeletal muscle cells in vitro and investigated the mechanisms involved. Parental and GLUT4myc-overexpressing L6 rat skeletal muscle cells were used. [3H]2-deoxyglucose (2DG) uptake was measured, and total and phosphorylated levels of specific proteins were examined by immunoblotting. Exposure of L6 cells to HI levels (100 nM) for 24 h decreased the acute-insulin-stimulated 2DG uptake, indicating insulin resistance. HI increased ser307 and ser636/639 phosphorylation of IRS-1 (to 184% ± 12% and 225% ± 28.9% of control, with p < 0.001 and p < 0.01, respectively) and increased the phosphorylation levels of mTOR (174% ± 6.7% of control, p < 0.01) and p70 S6K (228% ± 33.5% of control, p < 0.01). Treatment with RSV abolished these HI-induced responses. Furthermore, RSV increased the activation of AMPK and restored the insulin-mediated increase in plasma membrane GLUT4 glucose transporter levels. These data suggest that RSV has a potential to counteract the HI-induced muscle insulin resistance.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Resistência à Insulina/fisiologia , Músculo Esquelético/citologia , Resveratrol/farmacologia , Animais , Linhagem Celular , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina/metabolismo , Ratos , Serina-Treonina Quinases TOR/metabolismo
16.
Environ Toxicol Pharmacol ; 78: 103387, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32339907

RESUMO

Bisphenol-A (BPA), a widespread endocrine-disrupting chemical, has been recognized as a risk factor for metabolic disorders. BPA is considered to be involved in the impairment of carbohydrate and lipid metabolism but the underlying mechanisms still need to be elucidated. Present study was aimed to investigate the impact of BPA exposure on enzymatic and metabolic pathways that are responsible to regulate the carbohydrate and lipid metabolism. Experimental rats were exposed to different doses of BPA (50, 500, 2500 and 5000 µg/kg/day orally) dissolved in 1.5% dimethyl sulfoxide for a period of 3 months. Serum level of key metabolic enzymes (α-amylase, α-glucosidase, hexokinase, glucose-6-phosphatase and HMG-CoA-reductase) was measured by ELISA method. BPA-exposure suppressed the mRNA expression of gene encoding insulin resulting in poor insulin production. While hexokinase, acetyl-CoA carboxylase and squalene epoxide were up-regulated upon BPA exposure that justified the increased lipid profile. Moreover, BPA exposure showed considerably decreased glucose uptake through insulin signaling via Akt/GLUT4 pathways. There was a significant (p < 0.001) reduction in tissue level of glucose transporters. BPA significantly (p < 0.001) decreased the serum levels of oxidative stress biomarkers (GSH, CAT, and SOD). Serum levels of leptin, TNF-α, and IL-6 were rapidly increased upon exposure to BPA (p < 0.001). It was clearly evident from this study that BPA disturbed the carbohydrate and lipid metabolism after chronic exposure. It also accelerated the inflammatory processes by increasing the oxidative stress which ultimately lead towards the insulin resistance and impaired carbohydrate and lipid metabolism.


Assuntos
Compostos Benzidrílicos/toxicidade , Metabolismo dos Carboidratos/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Metabolismo dos Lipídeos/efeitos dos fármacos , Fenóis/toxicidade , Animais , Glicemia/efeitos dos fármacos , Transportador de Glucose Tipo 2/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Insulina/sangue , Redes e Vias Metabólicas/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pâncreas/efeitos dos fármacos , Pâncreas/metabolismo , Pâncreas/patologia , Ratos Wistar
17.
Life Sci ; 248: 117474, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32112869

RESUMO

BACKGROUND/OBJECTIVES: Nicotinamide N-methyltransferase (NNMT) is a novel regulator of energy homeostasis in adipocytes. NNMT expression in adipose tissue is increased in obesity and diabetes. Knockdown of NNMT prevents mice from developing diet-induced obesity, which is closely linked to insulin resistance. An early sign of systemic insulin resistance is reduced expression of glucose transporter 4 (GLUT4) selectively in adipose tissue. Adipose tissue-specific knockout and overexpression of GLUT4 cause reciprocal changes in NNMT expression. The aim of the current study was to elucidate the mechanism that regulates NNMT expression in adipocytes. METHODS: 3T3-L1 adipocytes were cultured in media with varying glucose concentrations or activators and inhibitors of intracellular pathways. NNMT mRNA and protein levels were measured with quantitative polymerase chain reaction and Western blotting. RESULTS: Glucose deprivation of 3T3-L1 adipocytes induced a 2-fold increase in NNMT mRNA and protein expression. This effect was mimicked by inhibition of glucose transport with phloretin, and by inhibition of glycolysis with the phosphoglucose isomerase inhibitor 2-deoxyglucose. Conversely, inhibition of the pentose phosphate pathway did not affect NNMT expression. Pharmacological activation of the cellular energy sensor AMP-activated protein kinase (AMPK) and inhibition of the mammalian target of rapamycin (mTOR) pathway caused an increase in NNMT levels that was similar to the effect of glucose deprivation. Activation of mTOR with MHY1485 prevented the effect of glucose deprivation on NNMT expression. Furthermore, upregulation of NNMT levels depended on functional autophagy and protein translation. CONCLUSION: Glucose availability regulates NNMT expression via an mTOR-dependent mechanism.


Assuntos
Adipócitos/efeitos dos fármacos , Transportador de Glucose Tipo 4/genética , Glucose/farmacologia , Nicotinamida N-Metiltransferase/genética , Serina-Treonina Quinases TOR/genética , Células 3T3-L1 , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Autofagia/efeitos dos fármacos , Autofagia/genética , Transporte Biológico/efeitos dos fármacos , Diferenciação Celular , Desoxiglucose/farmacologia , Metabolismo Energético/genética , Regulação da Expressão Gênica , Glucose/metabolismo , Transportador de Glucose Tipo 4/antagonistas & inibidores , Transportador de Glucose Tipo 4/metabolismo , Glucose-6-Fosfato Isomerase/antagonistas & inibidores , Glucose-6-Fosfato Isomerase/genética , Glucose-6-Fosfato Isomerase/metabolismo , Homeostase/genética , Camundongos , Morfolinas/farmacologia , Nicotinamida N-Metiltransferase/antagonistas & inibidores , Nicotinamida N-Metiltransferase/metabolismo , Via de Pentose Fosfato/efeitos dos fármacos , Via de Pentose Fosfato/genética , Floretina/farmacologia , Biossíntese de Proteínas , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Triazinas/farmacologia
18.
Indian J Pharmacol ; 52(1): 31-38, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32201444

RESUMO

OBJECTIVE: Our published literature indicated that chromium citrate could regulate the glycemic index in alloxaninduced diabetic mice. The present study investigated the mechanism of chromium citrate in insulin resistance (IR) buffalo rat liver (BRL) cells. MATERIALS And METHODS: Chromium citrate was synthesized in our laboratory. BRL cells were purchased from the Chinese Academy of Sciences Cell Bank. The glucose transport and IR affected by chromium citrate in BRL cells were examined. The Thiazolyl Blue Tetrazolium Bromide (MTT) and glucose assay experiments were measured by microplate ELISA reader. The protein kinase B (Akt), glucose transporter-4 (Glut4), and phosphor-AMP-activated protein kinase ß1 levels were tested by Western blot, and the mRNA expression of glucose transport proteins (Akt2, Glut4, and AMPactivated protein kinase α2 (AMPKα2)) and insulin sensitivity proteins (insulin receptor substrate1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), and peroxisome proliferator-activated receptor γ (PPARγ)) was measured by reverse transcription-polymerase chain reaction. RESULTS: The results indicated that the glucose absorption level of chromium citrate groups was higher than model group significantly. It demonstrated that chromium citrate could significantly improve glucose absorption in IR BRL cells. The Akt, Glut4, and phosphor-AMPKß1 levels in chromium citrate groups (at doses of 0.4, 0.2, and 0.1 µg Cr/mL) were markedly improved when compared with the other experiment groups, and chromium citrate could more effectively increase the Akt level than chromium trichloride. In addition, the mRNA expression of Akt2, Glut4, and AMPKα2 in chromium citrate groups was significantly improved when contrasted with model group. CONCLUSION: The consequences illustrated that chromium citrate can affect the IR BRL cells' ameliorating glucose transport and IR.


Assuntos
Compostos de Cromo/farmacologia , Glucose/metabolismo , Resistência à Insulina , Fígado/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Transportador de Glucose Tipo 4/genética , Proteínas Substratos do Receptor de Insulina/genética , Fígado/citologia , PPAR gama/genética , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Ratos Endogâmicos BUF
19.
Nutrients ; 12(3)2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32121211

RESUMO

This study aimed to investigate the long-term effects of training intervention and resting on protein expression and stability of peroxisome proliferator-activated receptor ß/δ (PPARß), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC1α), glucose transporter type 4 (GLUT4), and mitochondrial proteins, and determine whether glucose homeostasis can be regulated through stable expression of these proteins after training. Rats swam daily for 3, 6, 9, 14, or 28 days, and then allowed to rest for 5 days post-training. Protein and mRNA levels were measured in the skeletal muscles of these rats. PPARß was overexpressed and knocked down in myotubes in the skeletal muscle to investigate the effects of swimming training on various signaling cascades of PGC-1α transcription, insulin signaling, and glucose uptake. Exercise training (Ext) upregulated PPARß, PGC-1α, GLUT4, and mitochondrial enzymes, including NADH-ubiquinone oxidoreductase (NUO), cytochrome c oxidase subunit I (COX1), citrate synthase (CS), and cytochrome c (Cyto C) in a time-dependent manner and promoted the protein stability of PPARß, PGC-1α, GLUT4, NUO, CS, and Cyto C, such that they were significantly upregulated 5 days after training cessation. PPARß overexpression increased the PGC-1α protein levels post-translation and improved insulin-induced signaling responsiveness and glucose uptake. The present results indicate that Ext promotes the protein stability of key mitochondria enzymes GLUT4, PGC-1α, and PPARß even after Ext cessation.


Assuntos
Glucose/metabolismo , Insulina/farmacologia , Músculo Esquelético/metabolismo , PPAR beta/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Condicionamento Físico Animal , Animais , Transportador de Glucose Tipo 4/metabolismo , Meia-Vida , Masculino , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Proteínas Mitocondriais/metabolismo , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/efeitos dos fármacos , PPAR beta/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Biossíntese de Proteínas/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Ratos Wistar , Transcrição Genética/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
20.
Food Chem Toxicol ; 138: 111252, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32156565

RESUMO

The brain is a highly metabolic organ and requires regulatory mechanisms to meet its high energy demand, with the PI3K/Akt and AMPK signalling pathways being central regulators of cellular energy and metabolism, also making them major targets for the development of neurometabolic disorders. Fusaric acid (FA), a toxin of fungal origin, was found to be a potent hypotensive agent in vivo and in clinical trials by altering brain neurochemistry thus demonstrating its neurological effects. Notably, FA is a putative mitochondrial toxin, however, the metabolic effects of FA in the brain remains unknown. Therefore, this study investigates the neurometabolic effects of FA via alterations to Akt and AMPK signalling pathways in C57BL/6 mice at acute (1 day) and prolonged exposure (10 days). Following 1 day exposure, FA augmented Akt signalling by increasing Akt S473 phosphorylation and the upstream regulators PI3K, mTOR and p70S6K. Activated Akt showed inhibition of GSK3 activity with the simultaneous activation of AMPK, p53 phosphorylation and reduced GLUT-1 and -4 receptor expressions, potentially suppressing neuronal glucose entry. However, after 10 days exposure, FA dampened PI3K/Akt and AMPK signalling, but increased the expression of GLUT receptors (1 and 4) in mice brain. Further, FA significantly depleted ATP levels, at 10 days exposure, despite increased PDHE1ß activity (at both 1 and 10 days), strongly suggesting that FA mediates ATP depletion independent of metabolic signalling. In conclusion, FA mediates neurometabolic disturbances, at 1 and 10 day exposures, which may negatively influence normal brain aging and predispose to neurodegenerative disorders.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Ácido Fusárico/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosfatidilinositol 3-Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Serina-Treonina Quinases TOR/metabolismo
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