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Aziel Alvarado-Ojeda Z, Zamilpa A, Costet-Mejia A, Méndez-Martínez M, Trejo-Moreno C, Jiménez-Ferrer JE, Salazar-Martínez AM, Cruz-Muñoz ME, Fragoso G, Rosas-Salgado G. Hydroalcoholic extract from Sechium edule (Jacq.) S.w. root reverses oleic acid-induced steatosis and insulin resistance in vitro. Heliyon 2024; 10:e24567. [PMID: 38312619 PMCID: PMC10835324 DOI: 10.1016/j.heliyon.2024.e24567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/17/2023] [Accepted: 01/10/2024] [Indexed: 02/06/2024] Open
Abstract
Steatosis is characterized by fat accumulation and insulin resistance (IR) in hepatocytes, which triggers a pro-oxidant, pro-inflammatory environment that may eventually lead to cirrhosis or liver carcinoma. This work was aimed to assess the effect of Sechium edule root hydroalcoholic extract (rSe-HA) (rich in cinnamic and coumaric acid, among other phenolic compounds) on triglyceride esterification, lipid degradation, AMPK expression, and the phosphorylation of insulin receptor in a Ser312 residue, as well as on the redox status, malondialdehyde (MDA) production, and the production of proinflammatory cytokines in an in vitro model of steatosis induced by oleic acid, to help develop a phytomedicine that could reverse this pathology. rSe-HA reduced triglyceride levels in hepatocyte lysates, increased lipolysis by activating AMPK at Thr172, and improved the redox status, as evidenced by the concentration of glycerol and formazan, respectively. It also prevented insulin resistance (IR), as measured by glucose consumption and the phosphorylation of the insulin receptor at Ser312. It also prevented TNFα and IL6 production and decreased the levels of MDA and nitric oxide (ON). Our results indicate that rSe-HA reversed steatosis and controlled the proinflammatory and prooxidant environment in oleic acid-induced dysfunctional HepG2 hepatocytes, supporting its potential use to control this disorder.
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Affiliation(s)
- Zimri Aziel Alvarado-Ojeda
- Facultad de Medicina, Universidad Autónoma Del Estado de Morelos, Leñeros S/N, Cuernavaca, Morelos, 62350, Mexico
| | - Alejandro Zamilpa
- Laboratorio de Farmacología, Centro de Investigaciones Biomédicas Del Sur, Instituto Mexicano Del Seguro Social, Xochitepec, Morelos, 62790, Mexico
| | - Alejandro Costet-Mejia
- Laboratorio de Farmacología, Centro de Investigaciones Biomédicas Del Sur, Instituto Mexicano Del Seguro Social, Xochitepec, Morelos, 62790, Mexico
| | - Marisol Méndez-Martínez
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana-Xochimilco, 04960, Mexico City, Mexico
| | - Celeste Trejo-Moreno
- Facultad de Medicina, Universidad Autónoma Del Estado de Morelos, Leñeros S/N, Cuernavaca, Morelos, 62350, Mexico
| | - Jesús Enrique Jiménez-Ferrer
- Laboratorio de Farmacología, Centro de Investigaciones Biomédicas Del Sur, Instituto Mexicano Del Seguro Social, Xochitepec, Morelos, 62790, Mexico
| | - Ana Maria Salazar-Martínez
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Coyoacán, 04510, Mexico City, Mexico
| | - Mario Ernesto Cruz-Muñoz
- Facultad de Medicina, Universidad Autónoma Del Estado de Morelos, Leñeros S/N, Cuernavaca, Morelos, 62350, Mexico
| | - Gladis Fragoso
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Coyoacán, 04510, Mexico City, Mexico
| | - Gabriela Rosas-Salgado
- Facultad de Medicina, Universidad Autónoma Del Estado de Morelos, Leñeros S/N, Cuernavaca, Morelos, 62350, Mexico
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Lee DK, Jo SH, Lee ES, Ha KB, Park NW, Kong DH, Park SI, Park JS, Chung CH. DWN12088, A Prolyl-tRNA Synthetase Inhibitor, Alleviates Hepatic Injury in Nonalcoholic Steatohepatitis. Diabetes Metab J 2024; 48:97-111. [PMID: 38173372 PMCID: PMC10850270 DOI: 10.4093/dmj.2022.0367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/22/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGRUOUND Nonalcoholic steatohepatitis (NASH) is a liver disease caused by obesity that leads to hepatic lipoapoptosis, resulting in fibrosis and cirrhosis. However, the mechanism underlying NASH is largely unknown, and there is currently no effective therapeutic agent against it. DWN12088, an agent used for treating idiopathic pulmonary fibrosis, is a selective prolyl-tRNA synthetase (PRS) inhibitor that suppresses the synthesis of collagen. However, the mechanism underlying the hepatoprotective effect of DWN12088 is not clear. Therefore, we investigated the role of DWN12088 in NASH progression. METHODS Mice were fed a chow diet or methionine-choline deficient (MCD)-diet, which was administered with DWN12088 or saline by oral gavage for 6 weeks. The effects of DWN12088 on NASH were evaluated by pathophysiological examinations, such as real-time quantitative reverse transcription polymerase chain reaction, immunoblotting, biochemical analysis, and immunohistochemistry. Molecular and cellular mechanisms of hepatic injury were assessed by in vitro cell culture. RESULTS DWN12088 attenuated palmitic acid (PA)-induced lipid accumulation and lipoapoptosis by downregulating the Rho-kinase (ROCK)/AMP-activated protein kinase (AMPK)/sterol regulatory element-binding protein-1c (SREBP-1c) and protein kinase R-like endoplasmic reticulum kinase (PERK)/α subunit of eukaryotic initiation factor 2 (eIF2α)/activating transcription factor 4 (ATF4)/C/EBP-homologous protein (CHOP) signaling cascades. PA increased but DWN12088 inhibited the phosphorylation of nuclear factor-κB (NF-κB) p65 (Ser536, Ser276) and the expression of proinflammatory genes. Moreover, the DWN12088 inhibited transforming growth factor β (TGFβ)-induced pro-fibrotic gene expression by suppressing TGFβ receptor 1 (TGFβR1)/Smad2/3 and TGFβR1/glutamyl-prolyl-tRNA synthetase (EPRS)/signal transducer and activator of transcription 6 (STAT6) axis signaling. In the case of MCD-diet-induced NASH, DWN12088 reduced hepatic steatosis, inflammation, and lipoapoptosis and prevented the progression of fibrosis. CONCLUSION Our findings provide new insights about DWN12088, namely that it plays an important role in the overall improvement of NASH. Hence, DWN12088 shows great potential to be developed as a new integrated therapeutic agent for NASH.
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Affiliation(s)
- Dong-Keon Lee
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
- Division of Research Program, Scripps Korea Antibody Institute, Chuncheon, Korea
| | - Su Ho Jo
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Eun Soo Lee
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Kyung Bong Ha
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Na Won Park
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Deok-Hoon Kong
- Division of Research Program, Scripps Korea Antibody Institute, Chuncheon, Korea
| | - Sang-In Park
- Division of Research Program, Scripps Korea Antibody Institute, Chuncheon, Korea
| | - Joon Seok Park
- Drug Discovery Center, Daewoong Pharmaceutical Co. Ltd., Seoul, Korea
| | - Choon Hee Chung
- Department of Internal Medicine and Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
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Ha KB, Lee ES, Park NW, Jo SH, Shim S, Kim DK, Ahn CM, Chung CH. Beneficial Effects of a Curcumin Derivative and Transforming Growth Factor-β Receptor I Inhibitor Combination on Nonalcoholic Steatohepatitis. Diabetes Metab J 2023; 47:500-513. [PMID: 37096379 PMCID: PMC10404525 DOI: 10.4093/dmj.2022.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/19/2022] [Indexed: 04/26/2023] Open
Abstract
BACKGRUOUND Curcumin 2005-8 (Cur5-8), a derivative of curcumin, improves fatty liver disease via AMP-activated protein kinase activation and autophagy regulation. EW-7197 (vactosertib) is a small molecule inhibitor of transforming growth factor β (TGF-β) receptor I and may scavenge reactive oxygen species and ameliorate fibrosis through the SMAD2/3 canonical pathway. This study aimed to determine whether co-administering these two drugs having different mechanisms is beneficial. METHODS Hepatocellular fibrosis was induced in mouse hepatocytes (alpha mouse liver 12 [AML12]) and human hepatic stellate cells (LX-2) using TGF-β (2 ng/mL). The cells were then treated with Cur5-8 (1 μM), EW-7197 (0.5 μM), or both. In animal experiments were also conducted during which, methionine-choline deficient diet, Cur5-8 (100 mg/kg), and EW-7197 (20 mg/kg) were administered orally to 8-week-old C57BL/6J mice for 6 weeks. RESULTS TGF-β-induced cell morphological changes were improved by EW-7197, and lipid accumulation was restored on the administration of EW-7197 in combination with Cur5-8. In a nonalcoholic steatohepatitis (NASH)-induced mouse model, 6 weeks of EW-7197 and Cur5-8 co-administration alleviated liver fibrosis and improved the nonalcoholic fatty liver disease (NAFLD) activity score. CONCLUSION Co-administering Cur5-8 and EW-7197 to NASH-induced mice and fibrotic hepatocytes reduced liver fibrosis and steatohepatitis while maintaining the advantages of both drugs. This is the first study to show the effect of the drug combination against NASH and NAFLD. Similar effects in other animal models will confirm its potential as a new therapeutic agent.
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Affiliation(s)
- Kyung Bong Ha
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Eun Soo Lee
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Na Won Park
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Su Ho Jo
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Soyeon Shim
- Department of Pharmacy, College of Pharmacy, Ewha Womans University, Seoul, Korea
| | - Dae-Kee Kim
- Department of Pharmacy, College of Pharmacy, Ewha Womans University, Seoul, Korea
| | - Chan Mug Ahn
- Department of Basic Science, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Choon Hee Chung
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Research Institute of Metabolism and Inflammation, Yonsei University Wonju College of Medicine, Wonju, Korea
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Den Hartogh DJ, Vlavcheski F, Tsiani E. Muscle Cell Insulin Resistance Is Attenuated by Rosmarinic Acid: Elucidating the Mechanisms Involved. Int J Mol Sci 2023; 24:ijms24065094. [PMID: 36982168 PMCID: PMC10049470 DOI: 10.3390/ijms24065094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/16/2023] [Accepted: 01/26/2023] [Indexed: 03/30/2023] Open
Abstract
Obesity and elevated blood free fatty acid (FFA) levels lead to impaired insulin action causing insulin resistance in skeletal muscle, and contributing to the development of type 2 diabetes mellitus (T2DM). Mechanistically, insulin resistance is associated with increased serine phosphorylation of the insulin receptor substrate (IRS) mediated by serine/threonine kinases including mTOR and p70S6K. Evidence demonstrated that activation of the energy sensor AMP-activated protein kinase (AMPK) may be an attractive target to counteract insulin resistance. We reported previously that rosemary extract (RE) and the RE polyphenol carnosic acid (CA) activated AMPK and counteracted the FFA-induced insulin resistance in muscle cells. The effect of rosmarinic acid (RA), another polyphenolic constituent of RE, on FFA-induced muscle insulin resistance has never been examined and is the focus of the current study. Muscle cell (L6) exposure to FFA palmitate resulted in increased serine phosphorylation of IRS-1 and reduced insulin-mediated (i) Akt activation, (ii) GLUT4 glucose transporter translocation, and (iii) glucose uptake. Notably, RA treatment abolished these effects, and restored the insulin-stimulated glucose uptake. Palmitate treatment increased the phosphorylation/activation of mTOR and p70S6K, kinases known to be involved in insulin resistance and RA significantly reduced these effects. RA increased the phosphorylation of AMPK, even in the presence of palmitate. Our data indicate that RA has the potential to counteract the palmitate-induced insulin resistance in muscle cells, and further studies are required to explore its antidiabetic properties.
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Affiliation(s)
- Danja J Den Hartogh
- Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Filip Vlavcheski
- Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Evangelia Tsiani
- Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada
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Pavlovic K, Krako Jakovljevic N, Isakovic AM, Ivanovic T, Markovic I, Lalic NM. Therapeutic vs. Suprapharmacological Metformin Concentrations: Different Effects on Energy Metabolism and Mitochondrial Function in Skeletal Muscle Cells in vitro. Front Pharmacol 2022; 13:930308. [PMID: 35873556 PMCID: PMC9299382 DOI: 10.3389/fphar.2022.930308] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/16/2022] [Indexed: 11/30/2022] Open
Abstract
Metformin is an oral antidiabetic agent that has been widely used in clinical practice for over 60 years, and is currently the most prescribed antidiabetic drug worldwide. However, the molecular mechanisms of metformin action in different tissues are still not completely understood. Although metformin-induced inhibition of mitochondrial respiratory chain Complex I and activation of AMP-activated protein kinase have been observed in many studies, published data is inconsistent. Furthermore, metformin concentrations used for in vitro studies and their pharmacological relevance are a common point of debate. The aim of this study was to explore the effects of different metformin concentrations on energy metabolism and activity of relevant signaling pathways in C2C12 muscle cells in vitro. In order to determine if therapeutic metformin concentrations have an effect on skeletal muscle cells, we used micromolar metformin concentrations (50 µM), and compared the effects with those of higher, millimolar concentrations (5 mM), that have already been established to affect mitochondrial function and AMPK activity. We conducted all experiments in conditions of high (25 mM) and low glucose (5.5 mM) concentration, in order to discern the role of glucose availability on metformin action. According to our results, micromolar metformin treatment did not cause Complex I inhibition nor AMPK activation. Also, cells cultured in low glucose medium were more sensitive to Complex I inhibition, mitochondrial membrane depolarization and AMPK activation by millimolar metformin, but cells cultured in high glucose medium were more prone to induction of ROS production. In conclusion, even though suprapharmacological metformin concentrations cause Complex I inhibition and AMPK activation in skeletal muscle cells in vitro, therapeutic concentrations cause no such effect. This raises the question if these mechanisms are relevant for therapeutic effects of metformin in skeletal muscle.
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Affiliation(s)
- Kasja Pavlovic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center of Serbia, Belgrade, Serbia
| | - Nina Krako Jakovljevic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center of Serbia, Belgrade, Serbia
| | - Andjelka M Isakovic
- Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Tijana Ivanovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ivanka Markovic
- Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Nebojsa M Lalic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center of Serbia, Belgrade, Serbia
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Carnosic Acid Attenuates the Free Fatty Acid-Induced Insulin Resistance in Muscle Cells and Adipocytes. Cells 2022; 11:cells11010167. [PMID: 35011728 PMCID: PMC8750606 DOI: 10.3390/cells11010167] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/10/2021] [Accepted: 12/28/2021] [Indexed: 12/12/2022] Open
Abstract
Elevated blood free fatty acids (FFAs), as seen in obesity, impair insulin action leading to insulin resistance and Type 2 diabetes mellitus. Several serine/threonine kinases including JNK, mTOR, and p70 S6K cause serine phosphorylation of the insulin receptor substrate (IRS) and have been implicated in insulin resistance. Activation of AMP-activated protein kinase (AMPK) increases glucose uptake, and in recent years, AMPK has been viewed as an important target to counteract insulin resistance. We reported previously that carnosic acid (CA) found in rosemary extract (RE) and RE increased glucose uptake and activated AMPK in muscle cells. In the present study, we examined the effects of CA on palmitate-induced insulin-resistant L6 myotubes and 3T3L1 adipocytes. Exposure of cells to palmitate reduced the insulin-stimulated glucose uptake, GLUT4 transporter levels on the plasma membrane, and Akt activation. Importantly, CA attenuated the deleterious effect of palmitate and restored the insulin-stimulated glucose uptake, the activation of Akt, and GLUT4 levels. Additionally, CA markedly attenuated the palmitate-induced phosphorylation/activation of JNK, mTOR, and p70S6K and activated AMPK. Our data indicate that CA has the potential to counteract the palmitate-induced muscle and fat cell insulin resistance.
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Pavlović K, Lalić N. Cell models for studying muscle insulin resistance. MEDICINSKI PODMLADAK 2021. [DOI: 10.5937/mp72-31381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Type 2 diabetes is one of the most prevalent chronic diseases in the world today. Insulin resistance - a reduced responsiveness of tissues to insulin - is a hallmark of type 2 diabetes pathology. Skeletal muscle plays a pivotal role in glucose homeostasis - it is responsible for the majority of insulin-mediated glucose disposal and thus is one of the tissues most affected by insulin resistance. To study the molecular mechanisms of a disease, researchers often turn to cell models - they are inexpensive, easy to use, and exist in a controlled environment with few unknown variables. Cell models for exploring muscle insulin resistance are constructed using primary cell cultures or immortalised cell lines and treating them with fatty acids, high insulin or high glucose concentrations. The choice of cell culture, concentration and duration of the treatment and the methods for measuring insulin sensitivity, in order to confirm the model, are rarely discussed. Choosing an appropriate and physiologically relevant model for a particular topic of interest is required in order for the results to be reproducible, relevant, comparable and translatable to more complex biological systems. Cell models enable research that would otherwise be inaccessible but, especially when studying human disease, they do not serve a purpose if they are not in line with the biological reality. This review aims to summarise and critically evaluate the most commonly used cell models of muscle insulin resistance: the rationale for choosing these exact treatments and conditions, the protocols for constructing the models and the measurable outcomes used for confirming insulin resistance in the cells.
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Chrysophanol Alleviates Metabolic Syndrome by Activating the SIRT6/AMPK Signaling Pathway in Brown Adipocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7374086. [PMID: 33274005 PMCID: PMC7683138 DOI: 10.1155/2020/7374086] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/21/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
Chrysophanol, a primary active ingredient of Cassia mimosoides Linn or Rhei radix et rhizoma, has various pharmacological properties, including anticancer, antidiabetic, and anti-inflammatory, as well as blood lipid regulation. However, whether chrysophanol can mitigate obesity, and its underlying mechanisms remains unclear. This study investigated whether chrysophanol effects energy metabolism in high-fat diet- (HFD-) induced obese mice and fat-specific Sirtuin 6- (SIRT6-) knockout (FKO) mice, targeting the SIRT6/AMPK signaling pathway in brown and white fat tissue. Our results showed that chrysophanol can effectively inhibit lipid accumulation in vitro and reduce mice's body weight, improve insulin sensitivity and reduced fat content of mice, and induce energy consumption in HFD-induced obese mice by activating the SIRT6/AMPK pathway. However, a treatment with OSS-128167, an SIRT6 inhibitor, or si-SIRT6, SIRT6 target specific small interfering RNA, in vitro blocked chrysophanol inhibition of lipid accumulation. Similar results were obtained when blocking the AMPK pathway. Moreover, in the HFD-induced obese model with SIRT6 FKO mice, histological analysis and genetic test results showed that chrysophanol treatment did not reduce lipid droplets and upregulated the uncoupling protein 1 (UCP1) expression. Rather, it upregulated the expression of thermogenic genes and activated white fat breakdown by inducing phosphorylation of adenosine 5′-monophosphate- (AMP-) activated protein kinase (AMPK), both in vitro and in vivo. OSS-128167 or si-SIRT6 blocked chrysophanol's upregulation of peroxisome proliferator-activated receptor-γ coactivator-1α (Pgc-1α) and Ucp1 expression. In conclusion, this study demonstrated that chrysophanol can activate brown fat through the SIRT6/AMPK pathway and increase energy consumption, insulin sensitivity, and heat production, thereby alleviating obesity and metabolic disorders.
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Attenuation of Free Fatty Acid (FFA)-Induced Skeletal Muscle Cell Insulin Resistance by Resveratrol is Linked to Activation of AMPK and Inhibition of mTOR and p70 S6K. Int J Mol Sci 2020; 21:ijms21144900. [PMID: 32664532 PMCID: PMC7404286 DOI: 10.3390/ijms21144900] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/03/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Insulin resistance, a main characteristic of type 2 diabetes mellitus (T2DM), is linked to obesity and excessive levels of plasma free fatty acids (FFA). Studies indicated that significantly elevated levels of FFAs lead to skeletal muscle insulin resistance, by dysregulating the steps in the insulin signaling cascade. The polyphenol resveratrol (RSV) was shown to have antidiabetic properties but the exact mechanism(s) involved are not clearly understood. In the present study, we examined the effect of RSV on FFA-induced insulin resistance in skeletal muscle cells in vitro and investigated the mechanisms involved. Parental and GLUT4myc-overexpressing L6 rat skeletal myotubes 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 FFA palmitate decreased the insulin-stimulated glucose uptake, indicating insulin resistance. Palmitate increased ser307 (131% ± 1.84% of control, p < 0.001) and ser636/639 (148% ± 10.1% of control, p < 0.01) phosphorylation of IRS-1, and increased the phosphorylation levels of mTOR (174% ± 15.4% of control, p < 0.01) and p70 S6K (162% ± 20.2% of control, p < 0.05). Treatment with RSV completely abolished these palmitate-induced responses. In addition, RSV increased the activation of AMPK and restored the insulin-mediated increase in (a) plasma membrane GLUT4 glucose transporter levels and (b) glucose uptake. These data suggest that RSV has the potential to counteract the FFA-induced muscle insulin resistance.
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Shen S, Liao Q, Zhang T, Pan R, Lin L. Myricanol modulates skeletal muscle-adipose tissue crosstalk to alleviate high-fat diet-induced obesity and insulin resistance. Br J Pharmacol 2019; 176:3983-4001. [PMID: 31339170 DOI: 10.1111/bph.14802] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/18/2019] [Accepted: 07/18/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Skeletal muscle is the predominant site for glucose disposal and fatty acid consumption. Emerging evidence indicates that the crosstalk between adipose tissue and skeletal muscle is critical in maintaining insulin sensitivity and lipid homeostasis. The current study was designed to investigate whether myricanol improves insulin sensitivity and alleviates adiposity through modulating skeletal muscle-adipose tissue crosstalk. EXPERIMENTAL APPROACH The therapeutic effect of myricanol was evaluated on palmitic acid (PA)-treated C2C12 myotubes and high-fat diet (HFD)-fed mice. The crosstalk between myotubes and adipocytes was evaluated using Transwell assay. The cellular lipid content was examined by Nile red staining. The mitochondrial content was assessed by MitoTracker Green staining and citrate synthase activity, and the mitochondrial function was examined by Seahorse assay. Expression of mitochondria-related and insulin signalling pathway proteins was analysed by Western blot, and the irisin level was determined by elisa kit. KEY RESULTS Myricanol increased mitochondrial quantity and function through activating AMP-activated protein kinase, resulting in reduced lipid accumulation and enhanced insulin-stimulated glucose uptake, in PA-treated C2C12 myotubes. Furthermore, myricanol stimulated irisin production and secretion from myotubes to reduce lipid content in 3T3-L1 adipocytes. In HFD-fed mice, myricanol treatment alleviated adiposity and insulin resistance through enhancing lipid utilization and irisin production in skeletal muscle and inducing browning of inguinal fat. CONCLUSIONS AND IMPLICATIONS Myricanol modulates skeletal muscle-adipose tissue crosstalk, to stimulate browning of adipose tissue and improve insulin sensitivity in skeletal muscle. Myricanol might be a potential candidate for treating insulin resistance and obesity.
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Affiliation(s)
- Shengnan Shen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
| | - Qiwen Liao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
| | - Tian Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
| | - Ruile Pan
- Institute of Medicinal Plant Development, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Ligen Lin
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
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Varshney R, Mishra R, Das N, Sircar D, Roy P. A comparative analysis of various flavonoids in the regulation of obesity and diabetes: An in vitro and in vivo study. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.05.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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12
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Attenuation of Free Fatty Acid-Induced Muscle Insulin Resistance by Rosemary Extract. Nutrients 2018; 10:nu10111623. [PMID: 30400151 PMCID: PMC6267446 DOI: 10.3390/nu10111623] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/24/2018] [Accepted: 10/29/2018] [Indexed: 12/13/2022] Open
Abstract
Elevated blood free fatty acids (FFAs), as seen in obesity, impair muscle insulin action leading to insulin resistance and Type 2 diabetes mellitus. Serine phosphorylation of the insulin receptor substrate (IRS) is linked to insulin resistance and a number of serine/threonine kinases including JNK, mTOR and p70 S6K have been implicated in this process. Activation of the energy sensor AMP-activated protein kinase (AMPK) increases muscle glucose uptake, and in recent years AMPK has been viewed as an important target to counteract insulin resistance. We reported recently that rosemary extract (RE) increased muscle cell glucose uptake and activated AMPK. However, the effect of RE on FFA-induced muscle insulin resistance has never been examined. In the current study, we investigated the effect of RE in palmitate-induced insulin resistant L6 myotubes. Exposure of myotubes to palmitate reduced the insulin-stimulated glucose uptake, increased serine phosphorylation of IRS-1, and decreased the insulin-stimulated phosphorylation of Akt. Importantly, exposure to RE abolished these effects and the insulin-stimulated glucose uptake was restored. Treatment with palmitate increased the phosphorylation/activation of JNK, mTOR and p70 S6K whereas RE completely abolished these effects. RE increased the phosphorylation of AMPK even in the presence of palmitate. Our data indicate that rosemary extract has the potential to counteract the palmitate-induced muscle cell insulin resistance and further studies are required to explore its antidiabetic properties.
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The ameliorative effect of hemp seed hexane extracts on the Propionibacterium acnes-induced inflammation and lipogenesis in sebocytes. PLoS One 2018; 13:e0202933. [PMID: 30148860 PMCID: PMC6110517 DOI: 10.1371/journal.pone.0202933] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/10/2018] [Indexed: 11/21/2022] Open
Abstract
In this study, we investigated the anti-microbial, anti-inflammatory, and anti-lipogenic effects of hemp (Cannabis sativa L.) seed hexane extracts, focusing on the Propionibacterium acnes-triggered inflammation and lipogenesis. Hemp seed hexane extracts (HSHE) showed anti-microbial activity against P. acnes. The expression of iNOS, COX-2, and the subsequent production of nitric oxide and prostaglandin increased after infection of P. acnes in HaCaT cells, however, upon treating with HSHE, their expressions were reduced. P. acnes-induced expressions of IL-1β and IL-8 were also reduced. HSHE exerted anti-inflammatory effects by regulating NF-κB and MAPKs signaling and blunting the translocation of p-NF-κB to the nucleus in P. acnes-stimulated HaCaT cells. Moreover, P. acnes-induced phosphorylation of ERK and JNK, and their downstream targets c-Fos and c-Jun, was also inhibited by HSHE. In addition, the transactivation of AP-1 induced by P. acnes infection was also downregulated by HSHE. Notably, HSHE regulated inflammation and lipid biosynthesis via regulating AMPK and AKT/FoxO1 signaling in IGF-1-induced inflammation and lipogenesis of sebocytes. In addition, HSHE inhibited 5-lipoxygenase level and P. acnes-induced MMP-9 activity, and promoted collagen biosynthesis in vitro. Thus, HSHE could be utilized to treat acne vulgaris, through its anti-microbial, anti-inflammatory, anti-lipogenic, and collagen-promoting properties.
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Tanokashira D, Kurata E, Fukuokaya W, Kawabe K, Kashiwada M, Takeuchi H, Nakazato M, Taguchi A. Metformin treatment ameliorates diabetes-associated decline in hippocampal neurogenesis and memory via phosphorylation of insulin receptor substrate 1. FEBS Open Bio 2018; 8:1104-1118. [PMID: 29988567 PMCID: PMC6026705 DOI: 10.1002/2211-5463.12436] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/28/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
Age‐related reduction in adult hippocampal neurogenesis is correlated with cognitive impairment. Diabetes is a chronic systemic disease that negatively affects adult neural stem cells and memory functions in the hippocampus. Despite growing concern regarding the potential role of diabetic drugs in neural abnormalities, their effects on progressive deterioration of neurogenesis and cognitive functions remain unknown. Here, we show that the combination of aging and diabetes in mice causes a marked decrease in hippocampal neurogenesis along with memory impairment and elevated neuroinflammation. Prolonged treatment with metformin, a biguanide antidiabetic medication, promotes cell proliferation and neuronal differentiation and inhibits aging‐ and diabetes‐associated microglial activation, which is related to homeostatic neurogenesis, leading to enhanced hippocampal neurogenesis in middle‐aged diabetic mice. Although chronic therapy with metformin fails to achieve recovery from hyperglycemia, a key feature of diabetes in middle‐aged diabetic mice, it improves hippocampal‐dependent spatial memory functions accompanied by increased phosphorylation of adenosine monophosphate‐activated protein kinase (AMPK), atypical protein kinase C ζ (aPKC ζ), and insulin receptor substrate 1 (IRS1) at selective serine residues in the hippocampus. Our findings suggest that signaling networks acting through long‐term metformin‐stimulated phosphorylation of AMPK, aPKC ζ/λ, and IRS1 serine sites contribute to neuroprotective effects on hippocampal neurogenesis and cognitive function independent of a hypoglycemic effect.
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Affiliation(s)
- Daisuke Tanokashira
- Department of Integrative Aging Neuroscience National Center for Geriatrics and Gerontology Obu Japan
| | - Eiko Kurata
- Department of Neurology, Respirology, Endocrinology and Metabolism Miyazaki University School of Medicine Japan
| | - Wataru Fukuokaya
- Department of Neurology, Respirology, Endocrinology and Metabolism Miyazaki University School of Medicine Japan
| | - Kenshiro Kawabe
- Department of Neurology, Respirology, Endocrinology and Metabolism Miyazaki University School of Medicine Japan
| | - Mana Kashiwada
- Department of Integrative Aging Neuroscience National Center for Geriatrics and Gerontology Obu Japan
| | - Hideyuki Takeuchi
- Department of Neurology and Stroke Medicine Yokohama City University Graduate School of Medicine Japan
| | - Masamitsu Nakazato
- Department of Neurology, Respirology, Endocrinology and Metabolism Miyazaki University School of Medicine Japan
| | - Akiko Taguchi
- Department of Integrative Aging Neuroscience National Center for Geriatrics and Gerontology Obu Japan.,Department of Neurology, Respirology, Endocrinology and Metabolism Miyazaki University School of Medicine Japan
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Jung TW, Park HS, Choi GH, Kim D, Lee T. β-aminoisobutyric acid attenuates LPS-induced inflammation and insulin resistance in adipocytes through AMPK-mediated pathway. J Biomed Sci 2018; 25:27. [PMID: 29592806 PMCID: PMC5875012 DOI: 10.1186/s12929-018-0431-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 03/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND β-aminoisobutyric acid (BAIBA) is produced in skeletal muscle during exercise and has beneficial effects on obesity-related metabolic disorders such as diabetes and non-alcoholic fatty liver disease. Thus, it is supposed to prevent high fat diet (HFD)-induced inflammation and insulin resistance in adipose tissue though anti-inflammatory effects in obesity. Previous reports have also demonstrated strong anti-inflammatory effects of BAIBA. METHODS We used BAIBA treated fully differentiated 3T3T-L1 mouse adipocytes to investigate the effects of exogenous BAIBA on inflammation and insulin signaling in adipocytes. Insulin signaling-mediated proteins and inflammation markers were measured by Western blot analysis. Secretion of pro-inflammatory cytokines were measured by ELISA. Lipid accumulation in differentiated 3 T3-L1 cells was stained by Oil red-O. Statistical analysis was performed by ANOVA and student's t test. RESULTS BAIBA treatment suppressed adipogenesis assessed by adipogenic markers as well as lipid accumulation after full differentiation. We showed that BAIBA treatment stimulated AMP-activated protein kinase (AMPK) phosphorylation in a dose-dependent manner and lipopolysaccharide (LPS)-induced secretion of pro-inflammatory cytokines such as TNFα and MCP-1 was abrogated in BAIBA-treated 3 T3-L1 cells. Treatment of 3 T3-L1 cells with BAIBA reduced LPS-induced NFκB and IκB phosphorylation. Furthermore, BAIBA treatment ameliorated LPS-induced impairment of insulin signaling measured by IRS-1 and Akt phosphorylation and fatty acid oxidation. Suppression of AMPK by small interfering (si) RNA significantly restored these changes. CONCLUSIONS We demonstrated anti-inflammatory and anti-insulin resistance effects of BAIBA in differentiated 3 T3-L1 cells treated with LPS through AMPK-dependent signaling. These results provide evidence for the beneficial effects of BAIBA not only in liver and skeletal muscle cells but also in adipose tissue.
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Affiliation(s)
- Tae Woo Jung
- Research Administration Team, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea.,Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea
| | - Hyung Sub Park
- Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea
| | - Geum Hee Choi
- Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea
| | - Daehwan Kim
- Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea
| | - Taeseung Lee
- Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea. .,Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
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Tang S, Wu W, Tang W, Ge Z, Wang H, Hong T, Zhu D, Bi Y. Suppression of Rho-kinase 1 is responsible for insulin regulation of the AMPK/SREBP-1c pathway in skeletal muscle cells exposed to palmitate. Acta Diabetol 2017; 54:635-644. [PMID: 28265821 DOI: 10.1007/s00592-017-0976-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/19/2017] [Indexed: 11/28/2022]
Abstract
AIMS Clinical and experimental data suggest that early insulin therapy could reduce lipotoxicity in subjects and animal models with type 2 diabetes mellitus. However, the underlying mechanisms need to be clarified. Sterol regulatory element-binding protein 1c (SREBP-1c), which is negatively regulated by AMP-activated protein kinase (AMPK), plays a critical role in lipotoxicity and insulin resistance in skeletal muscle cells. Here, we investigated the effect and molecular mechanism of insulin intervention on the AMPK/SREBP-1c pathway in skeletal muscle cells with chronic exposure to palmitic acid (PA). METHODS Male C57BL/6 mice were fed with a high-fat diet for 12 weeks and were then treated with insulin, AMPK inhibitor, or metformin. L6 myotubes incubated with palmitic acid (PA) were treated with insulin or metformin. Dominant-negative AMPKα2 (DN-AMPKα2) lentivirus, AMPKα2 siRNA, or Rho-kinase 1 (ROCK1) siRNA were transfected into PA-treated L6 myotubes. RESULTS We found that the ability of PA to stimulate SREBP-1c and inhibit AMPK was reversed by insulin in L6 cells. Moreover, DN-AMPKα2 lentivirus and AMPKα2 siRNA were transfected into PA-treated L6 myotubes, and the decrease in SREBP-1c expression caused by insulin was blocked by AMPK inhibition independent of the phosphatidylinositol-4,5-biphosphate-3-kinase (PI3K)/AKT pathway. The serine/threonine kinase Rho-kinase (ROCK) 1, a downstream effector of the small G protein RhoA, was activated by PA. Interestingly, knockdown of ROCK1 by siRNA blocked the downregulation of AMPK phosphorylation under PA-treated L6 myotubes, which indicated that ROCK1 mediated the effect of insulin action on AMPK. CONCLUSIONS Our study indicated that insulin reduced lipotoxicity via ROCK1 and then improved AMPK/SREBP-1c signaling in skeletal muscle under PA-induced insulin resistance.
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Affiliation(s)
- Sunyinyan Tang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Wenjun Wu
- Department of Endocrinology, Wuxi People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China
| | - Wenjuan Tang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Zhijuan Ge
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Hongdong Wang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Ting Hong
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Dalong Zhu
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China.
| | - Yan Bi
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China.
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TNF-α stimulates endothelial palmitic acid transcytosis and promotes insulin resistance. Sci Rep 2017; 7:44659. [PMID: 28304381 PMCID: PMC5356338 DOI: 10.1038/srep44659] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/13/2017] [Indexed: 01/15/2023] Open
Abstract
Persistent elevation of plasma TNF-α is a marker of low grade systemic inflammation. Palmitic acid (PA) is the most abundant type of saturated fatty acid in human body. PA is bound with albumin in plasma and could not pass through endothelial barrier freely. Albumin-bound PA has to be transported across monolayer endothelial cells through intracellular transcytosis, but not intercellular diffusion. In the present study, we discovered that TNF-α might stimulate PA transcytosis across cardiac microvascular endothelial cells, which further impaired the insulin-stimulated glucose uptake by cardiomyocytes and promoted insulin resistance. In this process, TNF-α-stimulated endothelial autophagy and NF-κB signaling crosstalk with each other and orchestrate the whole event, ultimately result in increased expression of fatty acid transporter protein 4 (FATP4) in endothelial cells and mediate the increased PA transcytosis across microvascular endothelial cells. Hopefully the present study discovered a novel missing link between low grade systemic inflammation and insulin resistance.
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Yuan H, Hu Y, Zhu Y, Zhang Y, Luo C, Li Z, Wen T, Zhuang W, Zou J, Hong L, Zhang X, Hisatome I, Yamamoto T, Cheng J. Metformin ameliorates high uric acid-induced insulin resistance in skeletal muscle cells. Mol Cell Endocrinol 2017; 443:138-145. [PMID: 28042024 DOI: 10.1016/j.mce.2016.12.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/23/2016] [Accepted: 12/26/2016] [Indexed: 02/05/2023]
Abstract
Hyperuricemia occurs together with abnormal glucose metabolism and insulin resistance. Skeletal muscle is an important organ of glucose uptake, disposal, and storage. Metformin activates adenosine monophosphate-activated protein kinase (AMPK) to regulate insulin signaling and promote the translocation of glucose transporter type 4 (GLUT4), thereby stimulating glucose uptake to maintain energy balance. Our previous study showed that high uric acid (HUA) induced insulin resistance in skeletal muscle tissue. However, the mechanism of metformin ameliorating UA-induced insulin resistance in muscle cells is unknown and we aimed to determine it. In this study, differentiated C2C12 cells were exposed to UA (15 mg/dl), then reactive oxygen species (ROS) was detected with DCFH-DA and glucose uptake with 2-NBDG. The levels of phospho-insulin receptor substrate 1 (IRS1; Ser307), phospho-AKT (Ser473) and membrane GLUT4 were examined by western blot analysis. The impact of metformin on UA-induced insulin resistance was monitored by adding Compound C, an AMPK inhibitor, and LY294002, a PI3K/AKT inhibitor. Our data indicate that UA can increase ROS production, inhibit IRS1-AKT signaling and insulin-stimulated glucose uptake, and induce insulin resistance in C2C12 cells. Metformin can reverse this process by increasing intracellular glucose uptake and ameliorating UA-induced insulin resistance.
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Affiliation(s)
- Huier Yuan
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yaqiu Hu
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yuzhang Zhu
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yongneng Zhang
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Chaohuan Luo
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Zhi Li
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Tengfei Wen
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Wanling Zhuang
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Jinfang Zou
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Liangli Hong
- Department of Pathology, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Xin Zhang
- The Laboratory of Molecular Cardiology, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, Yonago, Japan
| | - Tetsuya Yamamoto
- Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Jidong Cheng
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
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Maniar K, Moideen A, Mittal A, Patil A, Chakrabarti A, Banerjee D. A story of metformin-butyrate synergism to control various pathological conditions as a consequence of gut microbiome modification: Genesis of a wonder drug? Pharmacol Res 2016; 117:103-128. [PMID: 27939359 DOI: 10.1016/j.phrs.2016.12.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/25/2016] [Accepted: 12/05/2016] [Indexed: 12/19/2022]
Abstract
The most widely prescribed oral anti-diabetic agent today in the world today is a member of the biguanide class of drugs called metformin. Apart from its use in diabetes, it is currently being investigated for its potential use in many diseases such as cancer, cardiovascular diseases, Alzheimer's disease, obesity, comorbidities of diabetes such as retinopathy, nephropathy to name a few. Numerous in-vitro and in-vivo studies as well as clinical trials have been and are being conducted with a vast amount of literature being published every day. Numerous mechanisms for this drug have been proposed, but they have been unable to explain all the actions observed clinically. It is of interest that insulin has a stimulatory effect on cellular growth. Metformin sensitizes the insulin action but believed to be beneficial in cancer. Like -wise metformin is shown to have beneficial effects in opposite sets of pathological scenario looking from insulin sensitization point of view. This requires a comprehensive review of the disease conditions which are claimed to be affected by metformin therapy. Such a comprehensive review is presently lacking. In this review, we begin by examining the history of metformin before it became the most popular anti-diabetic medication today followed by a review of its relevant molecular mechanisms and important clinical trials in all areas where metformin has been studied and investigated till today. We also review novel mechanistic insight in metformin action in relation to microbiome and elaborate implications of such aspect in various disease states. Finally, we highlight the quandaries and suggest potential solutions which will help the researchers and physicians to channel their research and put this drug to better use.
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Affiliation(s)
- Kunal Maniar
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Amal Moideen
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Ankur Mittal
- Department of Experimental Medicine & Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Amol Patil
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Amitava Chakrabarti
- Department of Pharmacology, Post Graduate Institute of Medical Education & Research, Chandigarh, India
| | - Dibyajyoti Banerjee
- Department of Experimental Medicine & Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh, India.
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ZHU RONGFENG, ZHENG JIANJUN, CHEN LIZHEN, GU BIN, HUANG SHENGLI. Astragaloside IV facilitates glucose transport in C2C12 myotubes through the IRS1/AKT pathway and suppresses the palmitate-induced activation of the IKK/IκBα pathway. Int J Mol Med 2016; 37:1697-705. [DOI: 10.3892/ijmm.2016.2555] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/29/2016] [Indexed: 11/05/2022] Open
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Palmitate activates mTOR/p70S6K through AMPK inhibition and hypophosphorylation of raptor in skeletal muscle cells: Reversal by oleate is similar to metformin. Biochimie 2015; 118:141-50. [PMID: 26344902 DOI: 10.1016/j.biochi.2015.09.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/02/2015] [Indexed: 01/24/2023]
Abstract
Excessive saturated free fatty acids (SFFAs; e.g. palmitate) in blood are a pathogenic factor in diabetes, obesity, cardiovascular disease and liver failure. In contrast, monounsaturated free fatty acids (e.g. oleate) prevent the toxic effect of SFFAs in various types of cells. The mechanism is poorly understood and involvement of the mTOR complex is untested. In the present study, we demonstrate that oleate preconditioning, as well as coincubation, completely prevented palmitate-induced markers of inflammatory signaling, insulin resistance and cytotoxicity in C2C12 myotubes. We then examined the effect of palmitate and/or oleate on the mammalian target of rapamycin (mTOR) signal path and whether their link is mediated by AMP-activated protein kinase (AMPK). Palmitate decreased the phosphorylation of raptor and 4E-BP1 while increasing the phosphorylation of p70S6K. Palmitate also inhibited phosphorylation of AMPK, but did not change the phosphorylated levels of mTOR or rictor. Oleate completely prevented the palmitate-induced dysregulation of mTOR components and restored pAMPK whereas alone it produced no signaling changes. To understand this more, we show activation of AMPK by metformin also prevented palmitate-induced changes in the phosphorylations of raptor and p70S6K, confirming that the mTORC1/p70S6K signaling pathway is responsive to AMPK activity. By contrast, inhibition of AMPK phosphorylation by Compound C worsened palmitate-induced changes and correspondingly blocked the protective effect of oleate. Finally, metformin modestly attenuated palmitate-induced insulin resistance and cytotoxicity, as did oleate. Our findings indicate that palmitate activates mTORC1/p70S6K signaling by AMPK inhibition and phosphorylation of raptor. Oleate reverses these effects through a metformin-like facilitation of AMPK.
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