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Ceglarek VM, Coelho ML, Coelho RL, Almeida DL, de Souza Rodrigues WDN, Camargo RL, Barella LF, de Freitas Mathias PC, Grassiolli S. Chronic leucine supplementation does not prevent the obesity and metabolic abnormalities induced by monosodium glutamate. CLINICAL NUTRITION EXPERIMENTAL 2020. [DOI: 10.1016/j.yclnex.2019.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Guadagnini D, Rocha GZ, Santos A, Assalin HB, Hirabara SM, Curi R, Oliveira AG, Prada PO, Saad MJA. Microbiota determines insulin sensitivity in TLR2-KO mice. Life Sci 2019; 234:116793. [PMID: 31465735 DOI: 10.1016/j.lfs.2019.116793] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/17/2019] [Accepted: 08/25/2019] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Environmental factors have a key role in the control of gut microbiota and obesity. TLR2 knockout (TLR2-/-) mice in some housing conditions are protected from diet-induced insulin resistance. However, in our housing conditions these animals are not protected from diet-induced insulin-resistance. AIM The aim of the present study was to investigate the influence of our animal housing conditions on the gut microbiota, glucose tolerance and insulin sensitivity in TLR2-/- mice. MATERIAL AND METHODS The microbiota was investigated by metagenomics, associated with hyperinsulinemic euglycemic clamp and GTT associated with insulin signaling through immunoblotting. RESULTS The results showed that TLR2-/- mice in our housing conditions presented a phenotype of metabolic syndrome characterized by insulin resistance, glucose intolerance and increase in body weight. This phenotype was associated with differences in microbiota in TLR2-/- mice that showed a decrease in the Proteobacteria and Bacteroidetes phyla and an increase in the Firmicutesphylum, associated with and in increase in the Oscillospira and Ruminococcus genera. Furthermore there is also an increase in circulating LPS and subclinical inflammation in TLR2-/-. The molecular mechanism that account for insulin resistance was an activation of TLR4, associated with ER stress and JNK activation. The phenotype and metabolic behavior was reversed by antibiotic treatment and reproduced in WT mice by microbiota transplantation. CONCLUSIONS Our data show, for the first time, that the intestinal microbiota can induce insulin resistance and obesity in an animal model that is genetically protected from these processes.
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Affiliation(s)
- Dioze Guadagnini
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Guilherme Zweig Rocha
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Andrey Santos
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Heloisa Balan Assalin
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Sandro Massao Hirabara
- Interdisciplinary Post-Graduate Program in Health Science, Cruzeiro do Sul University, Sao Paulo, Brazil
| | - Rui Curi
- Interdisciplinary Post-Graduate Program in Health Science, Cruzeiro do Sul University, Sao Paulo, Brazil
| | - Alexandre Gabarra Oliveira
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil.; Department of Physical Education, Biosciences Institute, São Paulo State University (UNESP), Rio Claro, SP, Brazil
| | - Patricia O Prada
- Graduate Program in Nutritional and Sport Sciences and Metabolism, School of Applied Sciences, University of Campinas- UNICAMP, Campinas, Brazil
| | - Mario J A Saad
- Department of Internal Medicine-FCM, University of Campinas-UNICAMP, Campinas, SP, Brazil..
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Vuolo MM, Lima GC, Batista ÂG, Carazin CBB, Cintra DE, Prado MA, Júnior MRM. Passion fruit peel intake decreases inflammatory response and reverts lipid peroxidation and adiposity in diet-induced obese rats. Nutr Res 2019; 76:106-117. [PMID: 32033839 DOI: 10.1016/j.nutres.2019.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 08/09/2019] [Accepted: 08/15/2019] [Indexed: 12/23/2022]
Abstract
This study investigated Passiflora edulis peel flour (PEPF) intake and its effect against high-fat diet-induced obesity. PEPF is a source of fiber and phenolic compounds, which can decrease oxidative stress and inflammatory cytokines, both linked to chronic inflammatory response and fat deposition in obesity. Therefore, we hypothesized that PEPF intake could decrease inflammatory cytokines and oxidative stress observed in obesity, leading to decrease of fatness and chronic inflammatory response. The aims of the study were to evaluate the lipid peroxidation, the expression of antioxidants enzymes, and inflammatory parameters in obese rats. Male Sprague-Dawley rats were divided into 3 groups (n = 8 per group) according to the diets: control (based on AIN-93G), high-fat (HF, 35% fat w/w), and HF with PEPF (HFPF), and the experiment lasted for 10 weeks. PEPF showed high dietary fiber content and bioactive compounds, such as ferulic acid, and β-carotene. PEPF intake was effective in reducing body weight gain (13.31%) and total body fat (22.58%). The lipid peroxidation in the liver and adipose tissue decreased in the HFPF group compared to HF-fed animals, whereas hepatic glutathione peroxidase and glutathione reductase activity and their expressions in the liver were higher in HFPF than HF. In addition, the PEPF intake decreased inflammatory cytokines in serum. These results suggest that PEPF intake decreases oxidative stress, possibly by the increase of antioxidant enzymes expression. Furthermore, PEPF decreases inflammatory response and protects from adiposity. Then, PEPF could act as an adjuvant to control of early parameters in obesity dysfunction.
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Affiliation(s)
- Milena Morandi Vuolo
- School of Food Engineering, Food and Nutrition Department, University of Campinas, Monteiro Lobato 80, Zip Code: 13083-862, Campinas, São Paulo, Brazil.
| | - Glaucia Carielo Lima
- Nutrition School- Federal University of Goias, 227 st, Qd 68, S/N-Setor Leste Universitário, Goiânia-GO, 74605-080, Brazil.
| | - Ângela Giovana Batista
- Department of Food and Nutrition, Federal University of Santa Maria (UFSM), Palmeira das Missões-RS, 98300-000, Brazil.
| | - Cinthia Baú Betim Carazin
- School of Food Engineering, Food and Nutrition Department, University of Campinas, Monteiro Lobato 80, Zip Code: 13083-862, Campinas, São Paulo, Brazil.
| | - Dennys Esper Cintra
- School of Applied Sciences, University of Campinas, Pedro Zaccaria, 1300, ZIP: 13484-350 Limeira, São Paulo, Brazil.
| | - Marcelo Alexandre Prado
- School of Food Engineering, Food and Nutrition Department, University of Campinas, Monteiro Lobato 80, Zip Code: 13083-862, Campinas, São Paulo, Brazil.
| | - Mário Roberto Maróstica Júnior
- School of Food Engineering, Food and Nutrition Department, University of Campinas, Monteiro Lobato 80, Zip Code: 13083-862, Campinas, São Paulo, Brazil.
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Abboud KY, Reis SK, Martelli ME, Zordão OP, Tannihão F, de Souza AZZ, Assalin HB, Guadagnini D, Rocha GZ, Saad MJA, Prada PO. Oral Glutamine Supplementation Reduces Obesity, Pro-Inflammatory Markers, and Improves Insulin Sensitivity in DIO Wistar Rats and Reduces Waist Circumference in Overweight and Obese Humans. Nutrients 2019; 11:nu11030536. [PMID: 30832230 PMCID: PMC6471297 DOI: 10.3390/nu11030536] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/18/2019] [Accepted: 02/24/2019] [Indexed: 12/16/2022] Open
Abstract
In the present study, we aimed to investigate whether chronic oral glutamine (Gln) supplementation may alter metabolic parameters and the inflammatory profile in overweight and obese humans as well as whether Gln may modulate molecular pathways in key tissues linked to the insulin action in rats. Thirty-nine overweight/obese volunteers received 30 g of Gln or alanine (Ala-control) for 14 days. Body weight (BW), waist circumference (WC), hormones, and pro-inflammatory markers were evaluated. To investigate molecular mechanisms, Gln or Ala was given to Wistar rats on a high-fat diet (HFD), and metabolic parameters, euglycemic hyperinsulinemic clamp with tracers, and Western blot were done. Gln reduced WC and serum lipopolysaccharide (LPS) in overweight volunteers. In the obese group, Gln diminished WC and serum insulin. There was a positive correlation between the reduction on WC and LPS. In rats on HFD, Gln reduced adiposity, improved insulin action and signaling, and reversed both defects in glucose metabolism in the liver and muscle. Gln supplementation increased muscle glucose uptake and reversed the increased hepatic glucose production, in parallel with a reduced glucose uptake in adipose tissue. This insulin resistance in AT was accompanied by enhanced IRS1 O-linked-glycosamine association in this tissue, but not in the liver and muscle. These data suggest that Gln supplementation leads to insulin resistance specifically in adipose tissue via the hexosamine pathway and reduces adipose mass, which is associated with improvement in the systemic insulin action. Thus, further investigation with Gln supplementation should be performed for longer periods in humans before prescribing as a beneficial therapeutic approach for individuals who are overweight and obese.
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Affiliation(s)
- Kahlile Youssef Abboud
- School of Applied Sciences, State University of Campinas (UNICAMP), Limeira 13484-350 SP, Brazil.
| | - Sabrina Karen Reis
- School of Applied Sciences, State University of Campinas (UNICAMP), Limeira 13484-350 SP, Brazil.
| | - Maria Eduarda Martelli
- School of Applied Sciences, State University of Campinas (UNICAMP), Limeira 13484-350 SP, Brazil.
| | - Olivia Pizetta Zordão
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
| | - Fabiana Tannihão
- School of Applied Sciences, State University of Campinas (UNICAMP), Limeira 13484-350 SP, Brazil.
| | | | - Heloisa Balan Assalin
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
| | - Dioze Guadagnini
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
| | - Guilherme Zweig Rocha
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
| | - Mario Jose Abdalla Saad
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
| | - Patricia Oliveira Prada
- School of Applied Sciences, State University of Campinas (UNICAMP), Limeira 13484-350 SP, Brazil.
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas 13083-887 SP, Brazil.
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da Silva KLC, Camacho AP, Mittestainer FC, Carvalho BM, Santos A, Guadagnini D, Oliveira AG, Saad MJA. Atorvastatin and diacerein reduce insulin resistance and increase disease tolerance in rats with sepsis. JOURNAL OF INFLAMMATION-LONDON 2018; 15:8. [PMID: 29760586 PMCID: PMC5944072 DOI: 10.1186/s12950-018-0184-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 04/30/2018] [Indexed: 12/30/2022]
Abstract
Background Sepsis is one of the leading causes of death among hospitalized patients. At the onset of this condition, there is an over-production of pro-inflammatory mediators that contribute to organ failure and death. The excess production of pro-inflammatory mediators also impairs insulin signaling, which may be a pathophysiological tissue marker of proinflammatory cytokine action before organ failure. Statins and diacerein have pleiotropic effects, such as the blockage of inflammatory signaling pathways, suggesting that these drugs may be an attractive therapeutic or prophylactic strategy against sepsis. The aim of the present study was to investigate whether a statin or diacerein can improve insulin signaling, disease tolerance and survival in sepsis by inhibiting inflammatory pathways. Methods We investigated the effect of these drugs on survival, tissue insulin signaling and inflammatory pathways in the liver and muscle of rats with sepsis induced by cecal ligation and puncture (CLP). Results The results showed that administration of medications, with anti-inflammatory ability, to septic animals increased survival and improved disease tolerance and insulin resistance in the liver and muscle. The treatment also attenuated ER stress, NF-κB, JNK activation and restored glucose-6-phosphatase (G6Pase) levels in the liver. Conclusions Our results indicate that atorvastatin and diacerein treatment can modulate inflammatory pathways and, in parallel, attenuate insulin resistance in sepsis. Since these two drugs have safety profiles and minimal side effects, we suggest that these drugs may be alternative therapies for the prevention or therapies for the treatment of insulin resistance in sepsis, which could potentially reduce mortality in patients with sepsis. Electronic supplementary material The online version of this article (10.1186/s12950-018-0184-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- K L C da Silva
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil
| | - A P Camacho
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil
| | - F C Mittestainer
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil
| | - B M Carvalho
- 2Department of Biology Science, Federal University of Pernambuco, Recife, PE Brazil
| | - A Santos
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil.,Departamento de Clínica Médica, FCM-UNICAMP, Cidade Universitária Zeferino Vaz, Campinas, SP 13083-887 Brazil
| | - D Guadagnini
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil
| | - A G Oliveira
- 3Department of Physical Education, São Paulo State University (UNESP), Bioscience Institute, Rio Claro, SP Brazil
| | - M J A Saad
- 1Department of Internal Medicine, State University of Campinas, Campinas, SP Brazil.,Departamento de Clínica Médica, FCM-UNICAMP, Cidade Universitária Zeferino Vaz, Campinas, SP 13083-887 Brazil
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Pedro MN, Rocha GZ, Guadagnini D, Santos A, Magro DO, Assalin HB, Oliveira AG, Pedro RDJ, Saad MJA. Insulin Resistance in HIV-Patients: Causes and Consequences. Front Endocrinol (Lausanne) 2018; 9:514. [PMID: 30233499 PMCID: PMC6133958 DOI: 10.3389/fendo.2018.00514] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/16/2018] [Indexed: 12/14/2022] Open
Abstract
Here we review how immune activation and insulin resistance contribute to the metabolic alterations observed in HIV-infected patients, and how these alterations increase the risk of developing CVD. The introduction and evolution of antiretroviral drugs over the past 25 years has completely changed the clinical prognosis of HIV-infected patients. The deaths of these individuals are now related to atherosclerotic CVDs, rather than from the viral infection itself. However, HIV infection, cART, and intestinal microbiota are associated with immune activation and insulin resistance, which can lead to the development of a variety of diseases and disorders, especially with regards to CVDs. The increase in LPS and proinflammatory cytokines circulating levels and intracellular mechanisms activate serine kinases, resulting in insulin receptor substrate-1 (IRS-1) serine phosphorylation and consequently a down regulation in insulin signaling. While lifestyle modifications and pharmaceutical interventions can be employed to treat these altered metabolic functions, the mechanisms involved in the development of these chronic complications remain largely unresolved. The elucidation and understanding of these mechanisms will give rise to new classes of drugs that will further improve the quality of life of HIV-infected patients, over the age of 50.
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Affiliation(s)
- Marcelo N. Pedro
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Guilherme Z. Rocha
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Dioze Guadagnini
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Andrey Santos
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Daniela O. Magro
- Department of Surgery, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Heloisa B. Assalin
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Alexandre G. Oliveira
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
- Biosciences Institute, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Rogerio de Jesus Pedro
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Mario J. A. Saad
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas-UNICAMP, Campinas, Brazil
- *Correspondence: Mario J. A. Saad
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Zanotto TM, Quaresma PGF, Guadagnini D, Weissmann L, Santos AC, Vecina JF, Calisto K, Santos A, Prada PO, Saad MJA. Blocking iNOS and endoplasmic reticulum stress synergistically improves insulin resistance in mice. Mol Metab 2016; 6:206-218. [PMID: 28180062 PMCID: PMC5279911 DOI: 10.1016/j.molmet.2016.12.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/02/2016] [Accepted: 12/12/2016] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Recent data show that iNOS has an essential role in ER stress in obesity. However, whether iNOS is sufficient to account for obesity-induced ER stress and Unfolded Protein Response (UPR) has not yet been investigated. In the present study, we used iNOS knockout mice to investigate whether high-fat diet (HFD) can still induce residual ER stress-associated insulin resistance. METHODS For this purpose, we used the intraperitoneal glucose tolerance test (GTT), euglycemic-hyperinsulinemic clamp, western blotting and qPCR in liver, muscle, and adipose tissue of iNOS KO and control mice on HFD. RESULTS The results of the present study demonstrated that, in HFD fed mice, iNOS-induced alteration in insulin signaling is an essential mechanism of insulin resistance in muscle, suggesting that iNOS may represent an important target that could be blocked in order to improve insulin sensitivity in this tissue. However, in liver and adipose tissue, the insulin resistance induced by HFD was only partially dependent on iNOS, and, even in the presence of genetic or pharmacological blockade of iNOS, a clear ER stress associated with altered insulin signaling remained evident in these tissues. When this ER stress was blocked pharmacologically, insulin signaling was improved, and a complete recovery of glucose tolerance was achieved. CONCLUSIONS Taken together, these results reinforce the tissue-specific regulation of insulin signaling in obesity, with iNOS being sufficient to account for insulin resistance in muscle, but in liver and adipose tissue ER stress and insulin resistance can be induced by both iNOS-dependent and iNOS-independent mechanisms.
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Key Words
- AKT, Protein kinase B
- ATF6, activating transcription factor 6
- Blocking
- ER, endoplasmic reticulum
- Endoplasmic reticulum stress
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- GTT, glucose tolerance test
- HFD, high-fat diet
- IKK, kappa α/β kinase
- IRE1, inositol requiring enzyme 1
- ITT, insulin tolerance test
- Improving
- Insulin resistance
- JNK, c-JunN-terminal kinase
- NO, nitric oxide
- PERK, protein kinase RNA-like ER kinase
- UPR, unfolded protein response
- iNOS
- iNOS, inducible nitric oxide synthase
- qPCR, real time PCR
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Affiliation(s)
- Tamires M Zanotto
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Paula G F Quaresma
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Dioze Guadagnini
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Lais Weissmann
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Andressa C Santos
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Juliana F Vecina
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Kelly Calisto
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Andrey Santos
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Patrícia O Prada
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; School of Applied Sciences, State University of Campinas (UNICAMP), Limeira, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Mario J A Saad
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Medical Clinics, Obesity and Comorbidities Research Center (O.C.R.C.), State University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Acupuncture Alters Expression of Insulin Signaling Related Molecules and Improves Insulin Resistance in OLETF Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:9651592. [PMID: 27738449 PMCID: PMC5055976 DOI: 10.1155/2016/9651592] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/27/2016] [Indexed: 11/17/2022]
Abstract
To determine effect of acupuncture on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats and to evaluate expression of insulin signaling components. Rats were divided into three groups: Sprague-Dawley (SD) rats, OLETF rats, and acupuncture+OLETF rats. Acupuncture was subcutaneously applied to Neiguan (PC6), Zusanli (ST36), and Sanyinjiao (SP6); in contrast, acupuncture to Shenshu (BL23) was administered perpendicularly. For Neiguan (PC6) and Zusanli (ST36), needles were connected to an electroacupuncture (EA) apparatus. Fasting blood glucose (FPG) was measured by glucose oxidase method. Plasma fasting insulin (FINS) and serum C peptide (C-P) were determined by ELISA. Protein and mRNA expressions of insulin signaling molecules were determined by Western blot and real-time RT-PCR, respectively. OLETF rats exhibit increased levels of FPG, FINS, C-P, and homeostasis model assessment-estimated insulin resistance (HOMA-IR), which were effectively decreased by acupuncture treatment. mRNA expressions of several insulin signaling related molecules IRS1, IRS2, Akt2, aPKCζ, and GLUT4 were decreased in OLETF rats compared to SD controls. Expression of these molecules was restored back to normal levels upon acupuncture administration. PI3K-p85α was increased in OLETF rats; this increase was also reversed by acupuncture treatment. Acupuncture improves insulin resistance in OLETF rats, possibly via regulating expression of key insulin signaling related molecules.
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Zhang X, Yu B, Yang D, Qiao Z, Cao T, Zhang P. Gastric volume reduction is essential for the remission of type 2 diabetes mellitus after bariatric surgery in nonobese rats. Surg Obes Relat Dis 2016; 12:1569-1576. [DOI: 10.1016/j.soard.2016.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 04/18/2016] [Indexed: 01/19/2023]
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Ryan AS, Serra MC. Skeletal Muscle CAP Expression Increases after Dietary Restriction and Aerobic Training in Women with a History of Gestational Diabetes. ACTA ACUST UNITED AC 2016; 5. [PMID: 28989819 DOI: 10.4172/2167-7182.1000354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose is to determine the effects of 6 months caloric restriction and aerobic training (3x/wk) (CR+AEX) on c-CBL associated protein (CAP) gene expression in women with a history of GDM. CAP is involved in cell signaling and protein ubiquitination, and is linked to the development of insulin resistance. Obese (BMI=32 ± 1 kg/m2, % fat=46 ± 2, X ± SEM), sedentary (VO2 max=21.2 ± 1.2 ml/kg/min), women aged 52 ± 2 years participated in 6 months D+WL (n=10) with body composition, fitness (VO2 max), and glucose tolerance testing. Insulin sensitivity was assessed during the last 30 min of 2-hour hyperinsulinemic-euglycemic clamps (40 mU.m-2.min-1) pre and post interventions. Vastus lateralis skeletal muscle biopsies (n=7) were conducted and CAP, GLUT4 and glycogen synthase (GS) gene expression measured by RT-PCR. No change in FFM by DXA was observed, but body weight decreased 8% with losses of total body fat mass (P<0.05) and a 10% increase in VO2 max (P<0.01). Glucose and insulin areas under the curve by OGTT decreased (P<0.05). Glucose utilization during the clamp increased 27% (23.1 ± 3.8 vs. 29.4 ± 3.6 umol.kg.min-1, P<0.05). Vastus lateralis skeletal muscle CAP expression increased 21% (P<0.05) but GLUT4 did not. Results suggest that changes in CAP could be involved in the improvement in glucose metabolism with caloric restriction and aerobic training in women with a history of gestational diabetes.
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Affiliation(s)
- Alice S Ryan
- Department of Medicine, University of Maryland School of Medicine, USA
| | - Monica C Serra
- Department of Medicine, University of Maryland School of Medicine, USA
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Carnagarin R, Dharmarajan AM, Dass CR. Molecular aspects of glucose homeostasis in skeletal muscle--A focus on the molecular mechanisms of insulin resistance. Mol Cell Endocrinol 2015; 417:52-62. [PMID: 26362689 DOI: 10.1016/j.mce.2015.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023]
Abstract
Among all the varied actions of insulin, regulation of glucose homeostasis is the most critical and intensively studied. With the availability of glucose from nutrient metabolism, insulin action in muscle results in increased glucose disposal via uptake from the circulation and storage of excess, thereby maintaining euglycemia. This major action of insulin is executed by redistribution of the glucose transporter protein, GLUT4 from intracellular storage sites to the plasma membrane and storage of glucose in the form of glycogen which also involves modulation of actin dynamics that govern trafficking of all the signal proteins of insulin signal transduction. The cellular mechanisms responsible for these trafficking events and the defects associated with insulin resistance are largely enigmatic, and this review provides a consolidated overview of the various molecular mechanisms involved in insulin-dependent glucose homeostasis in skeletal muscle, as insulin resistance at this major peripheral site impacts whole body glucose homeostasis.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Biomedical Science, Curtin University, Bentley 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia.
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Lee SH, Huang H, Choi K, Lee DH, Shi J, Liu T, Chun KH, Seo JA, Lima IS, Zabolotny JM, Wei L, Kim YB. ROCK1 isoform-specific deletion reveals a role for diet-induced insulin resistance. Am J Physiol Endocrinol Metab 2014; 306:E332-43. [PMID: 24326423 PMCID: PMC3920011 DOI: 10.1152/ajpendo.00619.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Rho kinase (ROCK) isoforms regulate insulin signaling and glucose metabolism negatively or positively in cultured cell lines and skeletal muscle. However, the in vivo function of the ROCK1 isoform in adipose tissue has not been addressed. To determine the specific role of the adipose ROCK1 isoform in the development of insulin resistance and obesity, mice lacking ROCK1 in adipose tissue globally or selectively were studied. Here, we show that insulin's ability to activate IRS-1/PI3K/Akt signaling was greatly enhanced in adipose tissue of ROCK1(-/-) mice compared with wild-type mice. These effects resulted from the inhibitory effect of ROCK1 on insulin receptor action, as evidenced by the fact that IR tyrosine phosphorylation was abolished in ROCK1(-/-) MEF cells when ROCK1 was reexpressed. Consistently, adipose-specific disruption of ROCK1 increased IR tyrosine phosphorylation in adipose tissue and modestly improved sensitivity to insulin in obese mice induced by high-fat feeding. This effect is independent of any changes in adiposity, number or size of adipocytes, and metabolic parameters, including glucose, insulin, leptin, and triglyceride levels, demonstrating a minimal effect of adipose ROCK1 on whole body metabolism. Enzymatic activity of ROCK1 in adipose tissue remained ∼50%, which likely originated from the fraction of stromal vascular cells, suggesting involvement of these cells for adipose metabolic regulation. Moreover, ROCK isoform activities were increased in adipose tissue of diet-induced or genetically obese mice. These data suggest that adipose ROCK1 isoform plays an inhibtory role for the regulation of insulin sensitivity in diet-induced obesity in vivo.
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Affiliation(s)
- Seung-Hwan Lee
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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13
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Abstract
The peel of the native Brazilian fruit jaboticaba is rich in anthocyanins, which are known for their anti-obesity effects in animal models. The aim of the present study was to evaluate the effects of freeze-dried jaboticaba peel powder (FDJPP) on a number of metabolic parameters in a model of diet-induced obesity. Mice (n 8 per group) were initially fed on a high-fat diet (HFD, 35 % w/w) for 4 weeks and then switched to a HFD supplemented with FDJPP (1, 2 or 4 % w/w) for an additional 6 weeks. Energy intake, weight loss, glucose tolerance, insulin resistance and lipid profile were determined, and the results were evaluated using ANOVA and Tukey's tests. The FDJPP exerted no protective effect on HFD-induced weight gain, hyperleptinaemia and glucose intolerance. However, the supplementation was effective to reduce insulin resistance, as evidenced in the insulin tolerance test, and subsequently confirmed by improved signal transduction through the insulin receptor/insulin receptor substrate-1/Akt/forkhead box protein pathway and by the attenuation of HFD-induced inflammation in the liver, verified by lower expressions of IL-1β and IL-6 and decreased phosphorylated IκB-α protein levels in all jaboticaba-treated mice. These results suggest that FDJPP may exert a protective role against obesity-associated insulin resistance.
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14
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Carvalho-Filho MA, Carvalho BM, Oliveira AG, Guadagnini D, Ueno M, Dias MM, Tsukumo DM, Hirabara SM, Reis LF, Curi R, Carvalheira JBC, Saad MJA. Double-stranded RNA-activated protein kinase is a key modulator of insulin sensitivity in physiological conditions and in obesity in mice. Endocrinology 2012; 153:5261-74. [PMID: 22948222 DOI: 10.1210/en.2012-1400] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase β. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase β phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.
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Affiliation(s)
- M A Carvalho-Filho
- Department of Internal Medicine, State University of Campinas, São Paulo, Brazil
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15
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Konrad SP, Farah V, Rodrigues B, Wichi RB, Machado UF, Lopes HF, D'Agord Schaan B, De Angelis K, Irigoyen MC. Monosodium glutamate neonatal treatment induces cardiovascular autonomic function changes in rodents. Clinics (Sao Paulo) 2012; 67:1209-14. [PMID: 23070349 PMCID: PMC3460025 DOI: 10.6061/clinics/2012(10)14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 05/17/2012] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The aim of this study was to evaluate cardiovascular autonomic function in a rodent obesity model induced by monosodium glutamate injections during the first seven days of life. METHOD The animals were assigned to control (control, n = 10) and monosodium glutamate (monosodium glutamate, n = 13) groups. Thirty-three weeks after birth, arterial and venous catheters were implanted for arterial pressure measurements, drug administration, and blood sampling. Baroreflex sensitivity was evaluated according to the tachycardic and bradycardic responses induced by sodium nitroprusside and phenylephrine infusion, respectively. Sympathetic and vagal effects were determined by administering methylatropine and propranolol. RESULTS Body weight, Lee index, and epididymal white adipose tissue values were higher in the monosodium glutamate group in comparison to the control group. The monosodium glutamate-treated rats displayed insulin resistance, as shown by a reduced glucose/insulin index (-62.5%), an increased area under the curve of total insulin secretion during glucose overload (39.3%), and basal hyperinsulinemia. The mean arterial pressure values were higher in the monosodium glutamate rats, whereas heart rate variability (>7 times), bradycardic responses (>4 times), and vagal (~38%) and sympathetic effects (~36%) were reduced as compared to the control group. CONCLUSION Our results suggest that obesity induced by neonatal monosodium glutamate treatment impairs cardiac autonomic function and most likely contributes to increased arterial pressure and insulin resistance.
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Affiliation(s)
- Signorá Peres Konrad
- Basic Health Sciences Institute, Physiology Department, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre/RS, Brazil
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16
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Tobar N, Oliveira AG, Guadagnini D, Bagarolli RA, Rocha GZ, Araújo TG, Santos-Silva JC, Zollner RL, Boechat LHB, Carvalheira JBC, Prada PO, Saad MJA. Diacerhein improves glucose tolerance and insulin sensitivity in mice on a high-fat diet. Endocrinology 2011; 152:4080-93. [PMID: 21896669 DOI: 10.1210/en.2011-0249] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Obesity and type 2 diabetes are characterized by insulin resistance, and the common basis of these events is a chronic and systemic inflammatory process marked by the activation of the c-Jun N-terminal kinase (JNK) and inhibitor-κB kinase (IKKβ)/nuclear factor-κB (NFκB) pathways, up-regulated cytokine synthesis, and endoplasmic reticulum dysfunction. The aim of this study was to evaluate the effects of diacerhein administration, an antiinflammatory drug that reduces the levels of inflammatory cytokines, on insulin sensitivity and signaling in diet-induced obese (DIO) mice. Swiss mice were fed with conventional chow (control group) or a high-fat diet (DIO group). Later, DIO mice were randomly subdivided into a new subgroup (DAR) that received 20 mg/kg diacerhein for 10 d. Western blotting was used to quantify the expression and phosphorylation of insulin receptor, insulin receptor substrate 1, and Akt and of inflammatory mediators that modulate insulin signaling in a negative manner (IKKβ, JNK, and inducible nitric oxide synthase). We show here, for the first time, that the administration of diacerhein in DIO mice improved endoplasmic reticulum stress, reduced JNK and IKKβ phosphorylation, and resulted in a marked improvement in fasting glucose, a decrease in macrophage infiltration in adipose tissue, and a reduced expression and activity of proinflammatory mediators accompanied by an improvement in the insulin signaling mainly in the liver and adipose tissue. Taken together, these results indicate that diacerhein treatment improves insulin sensitivity in obesity, mediated by the reversal of subclinical inflammation, and that this drug may be an alternative therapy for insulin resistance.
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Affiliation(s)
- Natália Tobar
- Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, Brazil
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17
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Impaired sympathoadrenal axis function contributes to enhanced insulin secretion in prediabetic obese rats. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:947917. [PMID: 21860615 PMCID: PMC3157162 DOI: 10.1155/2011/947917] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 06/13/2011] [Indexed: 12/22/2022]
Abstract
The involvement of sympathoadrenal axis activity in obesity onset was investigated using the experimental model of treating neonatal rats with monosodium L-glutamate. To access general sympathetic nervous system activity, we recorded the firing rates of sympathetic superior cervical ganglion nerves in animals. Catecholamine content and secretion from isolated adrenal medulla were measured. Intravenous glucose tolerance test was performed, and isolated pancreatic islets were stimulated with glucose and adrenergic agonists. The nerve firing rate of obese rats was decreased compared to the rate for lean rats. Basal catecholamine secretion decreased whereas catecholamine secretion induced by carbachol, elevated extracellular potassium, and caffeine in the isolated adrenal medulla were all increased in obese rats compared to control. Both glucose intolerance and hyperinsulinaemia were observed in obese rats. Adrenaline strongly inhibited glucose-induced insulin secretion in obese animals. These findings suggest that low sympathoadrenal activity contributes to impaired glycaemic control in prediabetic obese rats.
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18
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Oliveira AG, Carvalho BM, Tobar N, Ropelle ER, Pauli JR, Bagarolli RA, Guadagnini D, Carvalheira JB, Saad MJ. Physical exercise reduces circulating lipopolysaccharide and TLR4 activation and improves insulin signaling in tissues of DIO rats. Diabetes 2011; 60:784-96. [PMID: 21282367 PMCID: PMC3046839 DOI: 10.2337/db09-1907] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Insulin resistance in diet-induced obesity (DIO) is associated with a chronic systemic low-grade inflammation, and Toll-like receptor 4 (TLR4) plays an important role in the link among insulin resistance, inflammation, and obesity. The current study aimed to analyze the effect of exercise on TLR4 expression and activation in obese rats and its consequences on insulin sensitivity and signaling. RESEARCH DESIGN AND METHODS The effect of chronic and acute exercise was investigated on insulin sensitivity, insulin signaling, TLR4 activation, c-Jun NH(2)-terminal kinase (JNK) and IκB kinase (IKKβ) activity, and lipopolysaccharide (LPS) serum levels in tissues of DIO rats. RESULTS The results showed that chronic exercise reduced TLR4 mRNA and protein expression in liver, muscle, and adipose tissue. However, both acute and chronic exercise blunted TLR4 signaling in these tissues, including a reduction in JNK and IKKβ phosphorylation and IRS-1 serine 307 phosphorylation, and, in parallel, improved insulin-induced IR, IRS-1 tyrosine phosphorylation, and Akt serine phosphorylation, and reduced LPS serum levels. CONCLUSIONS Our results show that physical exercise in DIO rats, both acute and chronic, induces an important suppression in the TLR4 signaling pathway in the liver, muscle, and adipose tissue, reduces LPS serum levels, and improves insulin signaling and sensitivity. These data provide considerable progress in our understanding of the molecular events that link physical exercise to an improvement in inflammation and insulin resistance.
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19
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Calisto KL, Carvalho BDM, Ropelle ER, Mittestainer FC, Camacho ACA, Guadagnini D, Carvalheira JBC, Saad MJA. Atorvastatin improves survival in septic rats: effect on tissue inflammatory pathway and on insulin signaling. PLoS One 2010; 5:e14232. [PMID: 21151908 PMCID: PMC2997789 DOI: 10.1371/journal.pone.0014232] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Accepted: 11/13/2010] [Indexed: 12/14/2022] Open
Abstract
The aim of the present study was to investigate whether the survival-improving effect of atorvastatin in sepsis is accompanied by a reduction in tissue activation of inflammatory pathways and, in parallel, an improvement in tissue insulin signaling in rats. Diffuse sepsis was induced by cecal ligation and puncture surgery (CLP) in male Wistar rats. Serum glucose and inflammatory cytokines levels were assessed 24 h after CLP. The effect of atorvastatin on survival of septic animals was investigated in parallel with insulin signaling and its modulators in liver, muscle and adipose tissue. Atorvastatin improves survival in septic rats and this improvement is accompanied by a marked improvement in insulin sensitivity, characterized by an increase in glucose disappearance rate during the insulin tolerance test. Sepsis induced an increase in the expression/activation of TLR4 and its downstream signaling JNK and IKK/NF-κB activation, and blunted insulin-induced insulin signaling in liver, muscle and adipose tissue; atorvastatin reversed all these alterations in parallel with a decrease in circulating levels of TNF-α and IL-6. In summary, this study demonstrates that atorvastatin treatment increased survival, with a significant effect upon insulin sensitivity, improving insulin signaling in peripheral tissues of rats during peritoneal-induced sepsis. The effect of atorvastatin on the suppression of the TLR-dependent inflammatory pathway may play a central role in regulation of insulin signaling and survival in sepsis insult.
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Affiliation(s)
- Kelly Lima Calisto
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Bruno de Melo Carvalho
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Eduardo Rochete Ropelle
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | | | - Dioze Guadagnini
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | - Mario José Abdalla Saad
- Department of Internal Medicine, FCM, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- * E-mail:
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20
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Muthusamy VS, Saravanababu C, Ramanathan M, Bharathi Raja R, Sudhagar S, Anand S, Lakshmi BS. Inhibition of protein tyrosine phosphatase 1B and regulation of insulin signalling markers by caffeoyl derivatives of chicory ( Cichorium intybus) salad leaves. Br J Nutr 2010; 104:813-23. [PMID: 20444318 DOI: 10.1017/s0007114510001480] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Evaluations of molecular mechanisms of dietary plants with their active molecules are essential for the complete exploration of their nutritive and therapeutic value. In the present study, we investigated the effect of chicory (Cichorium intybus) salad leaves in inhibiting protein tyrosine phosphatase 1B (PTP1B), and evaluated their role in modulating the key markers involved in insulin cell signalling and adipogenesis using 3T3-L1 adipocytes. Bioactivity-directed purification studies enlightened the additive effects of chlorogenic acid (CGA) along with other caffeic acid derivatives present in methanolic extract of C. intybus (CME). Incubation of CME and CGA with 3T3-L1 adipocytes significantly enhanced the 2-deoxy-d-3[H]-glucose uptake and inhibited adipogenesis through altering the expressions of insulin signalling and adipogenesis markers. Extending to an in vivo model, the effect of CME was also investigated on insulin sensitivity in high-fat diet with low streptozotocin-induced diabetic rats. Supplementation of CME for 2 weeks reinstated the insulin sensitivity along with plasma metabolic profile. The present results demonstrate that the caffeoyl derivatives of chicory salad leaves show promising pharmacological effect on energy homoeostasis via PTP1B inhibition both in vitro and in vivo.
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Affiliation(s)
- V S Muthusamy
- Centre for Biotechnology, Tissue Culture and Drug Discovery Laboratory, Anna University, Chennai 600 025, Tamil Nadu, India
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21
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Chow L, From A, Seaquist E. Skeletal muscle insulin resistance: the interplay of local lipid excess and mitochondrial dysfunction. Metabolism 2010; 59:70-85. [PMID: 19766267 PMCID: PMC2789850 DOI: 10.1016/j.metabol.2009.07.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 06/02/2009] [Accepted: 07/09/2009] [Indexed: 01/07/2023]
Affiliation(s)
- Lisa Chow
- University of Minnesota Medical School, Minneapolis, MN 55455, United States.
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22
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Prada PO, Ropelle ER, Mourão RH, de Souza CT, Pauli JR, Cintra DE, Schenka A, Rocco SA, Rittner R, Franchini KG, Vassallo J, Velloso LA, Carvalheira JB, Saad MJ. EGFR tyrosine kinase inhibitor (PD153035) improves glucose tolerance and insulin action in high-fat diet-fed mice. Diabetes 2009; 58:2910-9. [PMID: 19696185 PMCID: PMC2780887 DOI: 10.2337/db08-0506] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE In obesity, an increased macrophage infiltration in adipose tissue occurs, contributing to low-grade inflammation and insulin resistance. Epidermal growth factor receptor (EGFR) mediates both chemotaxis and proliferation in monocytes and macrophages. However, the role of EGFR inhibitors in this subclinical inflammation has not yet been investigated. We investigated, herein, in vivo efficacy and associated molecular mechanisms by which PD153035, an EGFR tyrosine kinase inhibitor, improved diabetes control and insulin action. RESEARCH DESIGN AND METHODS The effect of PD153035 was investigated on insulin sensitivity, insulin signaling, and c-Jun NH(2)-terminal kinase (JNK) and nuclear factor (NF)-kappaB activity in tissues of high-fat diet (HFD)-fed mice and also on infiltration and the activation state of adipose tissue macrophages (ATMs) in these mice. RESULTS PD153035 treatment for 1 day decreased the protein expression of inducible nitric oxide synthase, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 in the stroma vascular fraction, suggesting that this drug reduces the M1 proinflammatory state in ATMs, as an initial effect, in turn reducing the circulating levels of TNF-alpha and IL-6, and initiating an improvement in insulin signaling and sensitivity. After 14 days of drug administration, there was a marked improvement in glucose tolerance; a reduction in insulin resistance; a reduction in macrophage infiltration in adipose tissue and in TNF-alpha, IL-6, and free fatty acids; accompanied by an improvement in insulin signaling in liver, muscle, and adipose tissue; and also a decrease in insulin receptor substrate-1 Ser(307) phosphorylation in JNK and inhibitor of NF-kappaB kinase (IKKbeta) activation in these tissues. CONCLUSIONS Treatment with PD153035 improves glucose tolerance, insulin sensitivity, and signaling and reduces subclinical inflammation in HFD-fed mice.
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Affiliation(s)
- Patricia O. Prada
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Eduardo R. Ropelle
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Rosa H. Mourão
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Claudio T. de Souza
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Jose R. Pauli
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Dennys E. Cintra
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - André Schenka
- Chemistry Institute, State University of Campinas, Campinas, Brazil
| | - Silvana A. Rocco
- Department of Pathology, State University of Campinas, Campinas, Brazil
| | - Roberto Rittner
- Department of Pathology, State University of Campinas, Campinas, Brazil
| | - Kleber G. Franchini
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - José Vassallo
- Chemistry Institute, State University of Campinas, Campinas, Brazil
| | - Lício A. Velloso
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - José B. Carvalheira
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
| | - Mario J.A. Saad
- Department of Internal Medicine, State University of Campinas, Campinas, Brazil
- Corresponding author: Mario J.A. Saad,
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Saito M, Lessard SJ, Rivas DA, Reeder DW, Hawley JA, Yaspelkis BB. Activation of atypical protein kinase Czeta toward TC10 is regulated by high-fat diet and aerobic exercise in skeletal muscle. Metabolism 2008; 57:1173-80. [PMID: 18702941 PMCID: PMC2597576 DOI: 10.1016/j.metabol.2008.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Accepted: 03/04/2008] [Indexed: 12/29/2022]
Abstract
We determined whether sustained aerobic exercise reverses high-fat diet-induced impairments in the c-Cbl associated protein (CAP)/Casitas b-lineage lymphoma (c-Cbl) signaling cascade in rodent skeletal muscle. Sprague-Dawley rats were placed into either control (n = 16) or high-fat-fed (n = 32) diet groups for 4 weeks. During a subsequent 4-week experimental period, 16 high-fat-fed rats remained sedentary, 16 high-fat-fed rats completed 4 weeks of exercise training, and control animals were sedentary and remained on the control diet. After the intervention period, animals were subjected to hind limb perfusions in the presence (n = 8 per group) or absence (n = 8 per group) of insulin. In the plasma membrane fractions, neither high-fat feeding nor exercise training altered adaptor protein with PH and SH2 domains, (APS), c-Cbl, or TC10 protein concentrations. In contrast, CAP protein concentration and insulin-stimulated plasma membrane c-Cbl tyrosine phosphorylation were reduced by high-fat feeding; but exercise training reversed these impairments. Of note was that insulin-stimulated atypical protein kinase Czeta kinase activity toward TC10 was reduced by high-fat feeding but normalized by exercise training. We conclude that sustained (4 weeks) exercise training can reverse high-fat diet-induced impairments on the CAP/c-Cbl pathway in high-fat-fed rodent skeletal muscle. We also provide the first evidence that the CAP/c-Cbl insulin signaling cascade in skeletal muscle may directly interact with components of the classic (phosphoinositide 3-kinase dependent) insulin signaling cascade.
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Affiliation(s)
- Misato Saito
- Exercise Biochemistry Laboratory, Department of Kinesiology, California State University Northridge, CA 91330-8287, USA
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24
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Bernard JR, Saito M, Liao YH, Yaspelkis BB, Ivy JL. Exercise training increases components of the c-Cbl-associated protein/c-Cbl signaling cascade in muscle of obese Zucker rats. Metabolism 2008; 57:858-66. [PMID: 18502271 DOI: 10.1016/j.metabol.2008.01.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 01/07/2008] [Indexed: 11/28/2022]
Abstract
The purpose of this investigation was to determine whether alterations in the c-Cbl-associated protein/c-Cbl pathway and/or p38-mitogen-activated protein kinase (p38 MAP kinase) were associated with improved skeletal muscle insulin responsiveness in exercise-trained obese Zucker rats. Obese Zucker rats ran 5 d/wk on a motorized treadmill for 90 minutes over a 7-week period. Age-matched obese Zucker rats (OB-SED) and their lean littermates (LN-SED) were obtained to serve as nontrained controls. Twenty-four (OB-EX-24 h) or 48 hours (OB-EX-48 h) after the last exercise bout, the trained rats were studied via the hind limb perfusion technique in the presence of insulin. Insulin-stimulated glucose uptake was significantly decreased across the skeletal muscle of OB-SED rats compared with LN-SED, but was normalized in the obese rats by 7 weeks of training. The insulin-stimulated plasma membrane protein concentrations of TC10 and glucose transporter 4 were reduced in the sedentary Zuckers, but both proteins were increased by the training protocol. Training did not increase insulin-stimulated p38 MAP kinase protein concentration, nor did it have an effect on insulin-stimulated p38 MAP kinase phosphorylation at the plasma membrane. These results suggest that skeletal muscle insulin resistance is associated with reduced expression of TC10 and that this deficiency can be corrected with exercise training.
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Affiliation(s)
- Jeffrey R Bernard
- Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX 78712, USA
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25
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Tsukumo DML, Carvalho-Filho MA, Carvalheira JBC, Prada PO, Hirabara SM, Schenka AA, Araújo EP, Vassallo J, Curi R, Velloso LA, Saad MJA. Loss-of-function mutation in Toll-like receptor 4 prevents diet-induced obesity and insulin resistance. Diabetes 2007; 56:1986-98. [PMID: 17519423 DOI: 10.2337/db06-1595] [Citation(s) in RCA: 647] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Obesity is associated with insulin resistance and a state of abnormal inflammatory response. The Toll-like receptor (TLR)4 has an important role in inflammation and immunity, and its expression has been reported in most tissues of the body, including the insulin-sensitive ones. Because it is activated by lipopolysaccharide and saturated fatty acids, which are inducers of insulin resistance, TLR4 may be a candidate for participation in the cross-talk between inflammatory and metabolic signals. Here, we show that C3H/HeJ mice, which have a loss-of-function mutation in TLR4, are protected against the development of diet-induced obesity. In addition, these mice demonstrate decreased adiposity, increased oxygen consumption, a decreased respiratory exchange ratio, improved insulin sensitivity, and enhanced insulin-signaling capacity in adipose tissue, muscle, and liver compared with control mice during high-fat feeding. Moreover, in these tissues, control mice fed a high-fat diet show an increase in IkappaB kinase complex and c-Jun NH(2)-terminal kinase activity, which is prevented in C3H/HeJ mice. In isolated muscles from C3H/HeJ mice, protection from saturated fatty acid-induced insulin resistance is observed. Thus, TLR4 appears to be an important mediator of obesity and insulin resistance and a potential target for the therapy of these highly prevalent medical conditions.
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Affiliation(s)
- Daniela M L Tsukumo
- Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, Brazil
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26
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Grassiolli S, Gravena C, de Freitas Mathias PC. Muscarinic M2 receptor is active on pancreatic islets from hypothalamic obese rat. Eur J Pharmacol 2007; 556:223-8. [PMID: 17174301 DOI: 10.1016/j.ejphar.2006.11.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 11/06/2006] [Accepted: 11/08/2006] [Indexed: 11/16/2022]
Abstract
Hypothalamic obese rats, obtained by neonatal treatment with monosodium L-glutamate (MSG), are hyperinsulinemic, and secrete more insulin than lean ones do when stimulated by glucose, while acetylcholine insulinotropic effect decreases. The effect of acetylcholine on glucose-induced insulin secretion is attributed to muscarinic receptors of pancreatic beta cells, mainly to M(3) subtype. However, it has been observed that activation of M(2) or M(4) subtypes causes inhibition of glucose-induced insulin secretion in insulin secreting cell line. Insulin secretion was measured, stimulated by glucose in the presence of acetylcholine plus methoctramine, a muscarinic M(2) antagonist, on pancreatic islets isolated from MSG-obese and lean rats to investigate whether impairment of acetylcholine insulinotropic effect on pancreatic islets from MSG-obese rats has any relationship with muscarinic M(2) receptor function in beta cells. Insulin secretion stimulated by 8.3 mM glucose was higher in islets from obese rats than from lean ones. Insulinotropic effect of acetylcholine was reported in islets of both animals, albeit less than in obese ones. Blockage of muscarinic M(2) receptor, using methoctramine at 1; 5 and 10 microM, increased acetylcholine secretory response in islets of obese rats, while no effect has been observed in lean ones. Results demonstrate that muscarinic M(2) receptors are functioning in pancreatic islets of MSG-obese rats. The inhibitory action of muscarinic M(2) receptor may be a mechanism by which acetylcholine discloses weak insulinotropic effect in MSG-obese rats.
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Affiliation(s)
- Sabrina Grassiolli
- Laboratory of Secretion Cell Biology, Department of Cell Biology and Genetics, State University of Maringá, Avenida Colombo 5790, 87020-900 Maringá, Brazil
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Swaminathan G, Tsygankov AY. The Cbl family proteins: ring leaders in regulation of cell signaling. J Cell Physiol 2006; 209:21-43. [PMID: 16741904 DOI: 10.1002/jcp.20694] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The proto-oncogenic protein c-Cbl was discovered as the cellular form of v-Cbl, a retroviral transforming protein. This was followed over the years by important discoveries, which identified c-Cbl and other Cbl-family proteins as key players in several signaling pathways. c-Cbl has donned the role of a multivalent adaptor protein, capable of interacting with a plethora of proteins, and has been shown to positively influence certain biological processes. The identity of c-Cbl as an E3 ubiquitin ligase unveiled the existence of an important negative regulatory pathway involved in maintaining homeostasis in protein tyrosine kinase (PTK) signaling. Recent years have also seen the emergence of novel regulators of Cbl, which have provided further insights into the complexity of Cbl-influenced pathways. This review will endeavor to provide a summary of current studies focused on the effects of Cbl proteins on various biological processes and the mechanism of these effects. The major sections of the review are as follows: Structure and genomic organization of Cbl proteins; Phosphorylation of Cbl; Interactions of Cbl; Localization of Cbl; Mechanism of effects of Cbl: (a) Ubiquitylation-dependent events: This section elucidates the mechanism of Cbl-mediated downregulation of EGFR and details the PTK and non-PTKs targeted by Cbl. In addition, it addresses the functional requirements for E3 Ubiquitin ligase activity of Cbl and negative regulation of Cbl-mediated downregulation of PTKs, (b) Adaptor functions: This section discusses the mechanisms of adaptor functions of Cbl in mitogen-activated protein kinase (MAPK) activation, insulin signaling, regulation of Ras-related protein 1 (Rap1), PI-3' kinase signaling, and regulation of Rho-family GTPases and cytoskeleton; Biological functions: This section gives an account of the diverse biological functions of Cbl and includes the role of Cbl in transformation, T-cell signaling and thymus development, B-cell signaling, mast-cell degranulation, macrophage functions, bone development, neurite growth, platelet activation, muscle degeneration, and bacterial invasion; Conclusions and perspectives.
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Affiliation(s)
- Gayathri Swaminathan
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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Prada PO, Pauli JR, Ropelle ER, Zecchin HG, Carvalheira JBC, Velloso LA, Saad MJA. Selective modulation of the CAP/Cbl pathway in the adipose tissue of high fat diet treated rats. FEBS Lett 2006; 580:4889-94. [PMID: 16919274 DOI: 10.1016/j.febslet.2006.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 07/28/2006] [Accepted: 08/01/2006] [Indexed: 02/07/2023]
Abstract
A high-fat diet (HFD) is associated with reduced glucose uptake in muscle, but not in adipose tissue. In the present study, we investigated whether a HFD can modulate glucose uptake in adipose tissue by increasing signal transduction through the CAP/Cbl pathway, independently of the PI3-K/Akt pathway. Our results suggest that, in HFD, the differential regulation of insulin-induced glucose uptake between skeletal muscle and adipose tissue may, in part, be a consequence of the CAP/Cbl/C3G pathway, since the expression of CAP and Cbl, and also the activation of this pathway were increased in adipose tissue but not in muscle.
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Affiliation(s)
- Patrícia Oliveira Prada
- Departamento de Clínica Médica da Universidade Estadual de Campinas, FCM-UNICAMP, Campinas, São Paulo 13083-970, Brazil
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Pourcet B, Fruchart JC, Staels B, Glineur C. Selective PPAR modulators, dual and pan PPAR agonists: multimodal drugs for the treatment of Type 2 diabetes and atherosclerosis. Expert Opin Emerg Drugs 2006; 11:379-401. [PMID: 16939380 DOI: 10.1517/14728214.11.3.379] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
More than 70% of patients with Type 2 diabetes mellitus (T2DM) die because of cardiovascular diseases. Current therapeutic strategies are based on separate treatment of insulin resistance and dyslipidaemia. Development of drugs with multimodal activities should improve management of the global cardiovascular risk of T2DM patients and result in better patient compliance. New therapeutic strategies are aimed at targeting the entire spectrum of dysfunctioning organs, cells and regulatory pathways implicated in the pathogenesis of T2DM, dyslipidaemia and atherosclerosis. PPAR family members play major roles in the regulation of lipid metabolism, glucose homeostasis and inflammatory processes, making these transcription factors ideal targets for therapeutic strategies against these diseases. This review discusses why PPARs and development of novel selective PPAR modulators, dual and pan PPAR agonists constitute promising approaches for the treatment of diabetes, dyslipidaemia and atherosclerosis.
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Affiliation(s)
- Benoit Pourcet
- Institut Pasteur de Lille, Département d'Athérosclérose, 01 rue du Professeur Calmette, BP 245, Lille 59019, France
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Vinciguerra M, Foti M. PTEN and SHIP2 phosphoinositide phosphatases as negative regulators of insulin signalling. Arch Physiol Biochem 2006; 112:89-104. [PMID: 16931451 DOI: 10.1080/13813450600711359] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Insulin resistance in peripheral tissues is the primary cause responsible for onset of type II diabetes mellitus. Recently, the genetic and biochemical dissection of intracellular signalling pathways transducing the metabolic and mitogenic effects of insulin has contributed to the understanding of the molecular causes of this insulin resistance. In particular, important efforts have been developed to comprehend the role of negative regulators of insulin signalling, since they might represent future therapeutical targets to reduce insulin resistance in peripheral tissues. Herein, we will briefly review major intracellular signalling pathways activated by insulin and how they are negatively regulated by distinct mechanisms. In particular, the role of PTEN and SHIP2, two phosphoinositide phosphatases recently implicated as negative modulators of insulin signalling, is in focus. Current knowledge on the role of PTEN and SHIP2 in insulin resistance, type II diabetes and related disorders will also be discussed.
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Affiliation(s)
- Manlio Vinciguerra
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Gupte A, Mora S. Activation of the Cbl insulin signaling pathway in cardiac muscle; Dysregulation in obesity and diabetes. Biochem Biophys Res Commun 2006; 342:751-7. [PMID: 16494846 DOI: 10.1016/j.bbrc.2006.02.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Accepted: 02/07/2006] [Indexed: 11/16/2022]
Abstract
In adipocytes, the Cbl/CAP dependent signaling pathway has been involved in regulating insulin-stimulated glucose uptake. We investigated activation of Cbl and its downstream effector TC10 in cardiac and skeletal muscle of Balb/C mice. Insulin administration resulted in Cbl phosphorylation in cardiac, skeletal muscle, and adipose tissue. Subsequent TC10 activation was detected only in heart and adipose tissue. c-Cbl and CAP gene expression was significantly reduced in the heart tissue of streptozotocin-induced diabetic animals, whereas no change was observed for other components of the pathway. No changes in Cbl expression were detected in hindlimb muscle. In leptin-/- obese mice Cbl expression in heart and adipose tissue was maintained, although insulin-mediated Cbl phosphorylation and subsequent TC10 activation were significantly reduced. In conclusion, our data demonstrate that Cbl/CAP/TC10 insulin signaling pathway is active in cardiac muscle and impaired during obesity and insulin deficiency.
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Affiliation(s)
- Anisha Gupte
- Division of Biology, Kansas State University, 232 Ackert Hall, Manhattan, KS 66506, USA
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Bernard JR, Reeder DW, Herr HJ, Rivas DA, Yaspelkis BB. High-fat feeding effects on components of the CAP/Cbl signaling cascade in Sprague-Dawley rat skeletal muscle. Metabolism 2006; 55:203-12. [PMID: 16423627 DOI: 10.1016/j.metabol.2005.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 08/21/2005] [Indexed: 10/25/2022]
Abstract
The aim of this investigation was to determine whether the CAP (Cbl-associated protein)/Cbl signaling cascade is present and responsive to insulin in skeletal muscle and if high-fat feeding impairs insulin-stimulated activation of this signaling cascade. Sprague-Dawley rats were assigned to either control (n = 16) or high fat-fed (n = 16) dietary groups. After a 12-week dietary period, animals were subjected to hind limb perfusions in the presence (n = 8 per group) or absence (n = 8 per group) of insulin. High-fat feeding reduced rates of insulin-stimulated skeletal muscle phosphatidylinositol 3-kinase activity and 3-O-methylglucose transport. In plasma membrane fractions, neither the high-fat diet nor insulin altered the insulin receptor beta subunit (IR-beta), APS (adaptor protein containing PH and SH2 domains), c-Cbl, or TC10 protein concentration, but high-fat feeding did decrease CAP protein concentration. APS, c-Cbl, CAP, and TC10 messenger RNA were present in the skeletal muscle and reflected the protein concentration of experimental groups. Despite insulin-stimulated plasma membrane IR-beta tyrosine phosphorylation being unaffected by high-fat feeding, c-Cbl tyrosine phosphorylation, the kinase activity of IR-beta toward APS, and glucose transporter 4 protein concentration were all significantly reduced in insulin-stimulated plasma membrane prepared from the skeletal muscle of high fat-fed animals. These findings suggest that the CAP/Cbl signaling cascade is present in skeletal muscle, activated by insulin, and impaired by high-fat feeding.
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Affiliation(s)
- Jeffrey R Bernard
- Department of Kinesiology, College of Health and Human Development, California State University Northridge, Northridge, CA 91330-8287, USA
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Guo L, Tabrizchi R. Peroxisome proliferator-activated receptor gamma as a drug target in the pathogenesis of insulin resistance. Pharmacol Ther 2005; 111:145-73. [PMID: 16305809 DOI: 10.1016/j.pharmthera.2005.10.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 10/03/2005] [Indexed: 01/08/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. The activation of PPAR-gamma, an isotype of PPARs, can either increase or decrease the transcription of target genes. The genes controlled by this form of PPAR have been shown to encode proteins or peptides that participate in the pathogenesis of insulin resistance. Insulin resistance is defined as a state of reduced responsiveness to normal circulating concentrations of insulin and it often co-exists with central obesity, hypertension, dyslipidemia, and atherosclerosis. There is substantial evidence that links obesity with insulin resistance and type-2 diabetes. The early phase of obesity-related insulin resistance has 2 components: (a) interruption of lipid homeostasis leading to the increased plasma concentration of fatty acids that is normally suppressed by the activation of PPAR-gamma, and (b) activation of factors such as cytokines depressed by PPAR-gamma that cause insulin resistance. Therefore, it is logical to suggest that activation of PPAR-gamma may partially reverse the state of insulin resistance. Evidently, activation of the nuclear receptor, PPAR-gamma, by thiazolidinediones has been reported to ameliorate insulin resistance. Although hepatotoxity and possibility to induce congestive heart failure (CHF) limit the widely use of thiazolodinediones, they are still powerful weapon to fight against insulin resistance and type-2 diabetes if use properly. This article reviews the physiology of PPAR-gamma and insulin-signaling transduction, the pathogenesis of insulin resistance in obesity-related type-2 diabetes, the pharmacological role of PPAR-gamma in insulin resistance, and additional effects of thiazolidinediones.
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Affiliation(s)
- Liang Guo
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3V6
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Thong FSL, Dugani CB, Klip A. Turning signals on and off: GLUT4 traffic in the insulin-signaling highway. Physiology (Bethesda) 2005; 20:271-84. [PMID: 16024515 DOI: 10.1152/physiol.00017.2005] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Insulin stimulation of glucose uptake into skeletal muscle and adipose tissues is achieved by accelerating glucose transporter GLUT4 exocytosis from intracellular compartments to the plasma membrane and minimally reducing its endocytosis. The round trip of GLUT4 is intricately regulated by diverse signaling molecules impinging on specific compartments. Here we highlight the key molecular signals that are turned on and off by insulin to accomplish this task.
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Affiliation(s)
- Farah S L Thong
- Programme in Cell Biology, The Hospital for Sick Children, Ontario, Canada
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Zorzano A, Palacín M, Gumà A. Mechanisms regulating GLUT4 glucose transporter expression and glucose transport in skeletal muscle. ACTA ACUST UNITED AC 2005; 183:43-58. [PMID: 15654919 DOI: 10.1111/j.1365-201x.2004.01380.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Skeletal muscle is a major glucose-utilizing tissue in the absorptive state and the major glucose transporter expressed in muscle in adulthood is GLUT4. GLUT4 expression is exquisitely regulated in muscle and this seems important in the regulation of insulin-stimulated glucose uptake by this tissues. Thus, muscle GLUT4 overexpression in transgenic animals ameliorates insulin resistance associated with obesity or diabetes. Recent information indicates that glut4 gene transcription is regulated by a number of factors in skeletal muscle that include MEF2, MyoD myogenic proteins, thyroid hormone receptors, Kruppel-like factor KLF15, NF1, Olf-1/Early B cell factor and GEF/HDBP1. In addition, studies in vivo indicate that under normal conditions the activity of the muscle-specific GLUT4 enhancer is low in adult skeletal muscle compared with the maximal potential activity that it can attain at high levels of the MRF transcription factors, MEF2, and TRalpha1. This finding indicates that glut4 transcription may be greatly up-regulated via activation of this enhancer through an increase in the levels of expression or activity of these transcription factors. Understanding the molecular basis of the expression of glut4 will be useful for the appropriate therapeutic design of treatments for insulin-resistant states. The nature of the intracellular signals that mediate the stimulation of glucose transport in response to insulin or exercise is also reviewed.
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Affiliation(s)
- A Zorzano
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, and IRBB- Parc Científic de Barcelona, Barcelona, Spain
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Cardoso AR, Carvalho CRO, Velloso LA, Brenelli SL, Saad MJA, Carvalheira JBC. Effect of thiopental, pentobarbital and diethyl ether on early steps of insulin action in liver and muscle of the intact rat. Life Sci 2005; 76:2287-97. [PMID: 15748623 DOI: 10.1016/j.lfs.2004.10.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2004] [Accepted: 10/04/2004] [Indexed: 02/07/2023]
Abstract
A large number of experimental studies have investigated insulin signaling in rats. In these studies different anaesthetics have been used to anaesthetize rats. However, the direct effects of anaesthetics on the regulation of the early steps of insulin action are not known. In the present study, we investigated the effect of thiopental, pentobarbital and diethyl ether on the plasma glucose disappearance rate, IR, IRS-1 and IRS-2 tyrosine phosphorylation, IRSs association with PI 3-kinase, Akt and Erk phosphorylation, in liver and muscle of rats. Fasting plasma glucose levels were higher in animals anaesthetized with ether. No differences in plasma glucose disappearance rates were observed, however. Insulin-induced IR, IRS-1 and IRS-2 tyrosine phosphorylation, association of these substrates with PI 3-kinase and Akt and ERK phosphorylation were similar in the three groups of animals in both tissues. These data suggest that both thiopental and pentobarbital may be used in studies where changes in insulin signaling are being measured and where adequate general anaesthesia is required.
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Affiliation(s)
- Adilson R Cardoso
- Departamento de Anestesia, FCM, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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Bernard JR, Crain AM, Rivas DA, Herr HJ, Reeder DW, Yaspelkis BB. Chronic aerobic exercise enhances components of the classical and novel insulin signalling cascades in Sprague-Dawley rat skeletal muscle. ACTA ACUST UNITED AC 2005; 183:357-66. [PMID: 15799772 DOI: 10.1111/j.1365-201x.2005.01408.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AIM The aim of this study was to provide a more extensive evaluation of the effects of chronic aerobic exercise on various components of the insulin signalling cascade in normal rodent skeletal muscle because of the limited body of literature that exists in this area of investigation. METHODS Male Sprague-Dawley rats were assigned to either control (n = 7) or chronic aerobic exercise (n = 7) groups. Aerobic exercise animals were run 3 day week(1) for 45 min on a motor-driven treadmill (32 m min(1), 15% grade) for a 12 week period. Following the training period, all animals were subjected to hind limb perfusion in the presence of 500 microU mL(1) insulin to determine what effect chronic aerobic training had on various components of the insulin signalling cascade, c-Cbl protein concentration and c-Cbl phosphorylation. RESULTS Twelve weeks of aerobic training did not alter skeletal muscle Akt 1/2 protein concentration, Akt Ser 473 phosphorylation, Akt Thr 308 phosphorylation, Akt 1 activity, aPKC-zeta protein concentration, aPKC-lambda protein concentration or c-Cbl protein concentration. In contrast, chronic aerobic exercise increased insulin-stimulated phosphatidylinositol 3-kinase, Akt 2 kinase and aPKC-zeta/lambda kinase activities, as well as c-Cbl tyrosine phosphorylation, in a fibre type specific response to aerobic training. In addition, chronic aerobic exercise enhanced insulin-stimulated plasma membrane glucose transporter 4 (GLUT4) protein concentration. CONCLUSION Collectively, these findings suggest that chronic aerobic exercise enhances components of both the classical and novel insulin signalling cascades in normal rodent skeletal muscle, which may contribute to an increased insulin-stimulated plasma membrane GLUT4 protein concentration.
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Affiliation(s)
- J R Bernard
- Exercise Biochemistry Laboratory, Department of Kinesiology, College of Health and Human Development, California State University Northridge, 91330-8287, USA
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Ueno M, Carvalheira JBC, Tambascia RC, Bezerra RMN, Amaral ME, Carneiro EM, Folli F, Franchini KG, Saad MJA. Regulation of insulin signalling by hyperinsulinaemia: role of IRS-1/2 serine phosphorylation and the mTOR/p70 S6K pathway. Diabetologia 2005; 48:506-18. [PMID: 15692808 DOI: 10.1007/s00125-004-1662-6] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Accepted: 11/11/2004] [Indexed: 02/07/2023]
Abstract
AIM/HYPOTHESIS Several epidemiological studies have suggested an association between chronic hyperinsulinaemia and insulin resistance. However, the causality of this relationship remains uncertain. METHODS We performed chronic hyperinsulinaemic-euglycaemic clamps and delineated, by western blotting, an IR/IRSs/phosphatidylinositol 3-kinase(PI[3]K)/Akt pathway in insulin-responsive tissues of hyperinsulinaemic rats. IRS-1/2 serine phosphorylation, IR/protein tyrosine phosphatase 1B (PTP1B) association, and mammalian target of rapamycin (mTOR)/p70 ribosomal S6 kinase (p70 S6K) activity were also evaluated in the liver, skeletal muscle and white adipose tissue of hyperinsulinaemic animals. RESULTS We found that chronic hyperinsulinaemic rats have insulin resistance and reduced levels of glycogen content in liver and muscle. In addition, we demonstrated an impairment of the insulin-induced IR/IRSs/PI3K/Akt pathway in liver and muscle of chronic hyperinsulinaemic rats that parallels increases in IRS1/2 serine phosphorylation, IR/PTP1B association and mTOR activity. Despite a higher association of IR/PTP1B, there was an increase in white adipose tissue of chronic hyperinsulinaemic rats in IRS-1/2 protein levels, tyrosine phosphorylation and IRSs/PI3K association, which led to an increase in basal Akt serine phosphorylation. No increases in IRS-1/2 serine phosphorylation and mTOR activity were observed in white adipose tissue. Rapamycin reversed the insulin resistance and the changes induced by hyperinsulinaemia in the three tissues studied. CONCLUSIONS/INTERPRETATION Our data provide evidence that chronic hyperinsulinaemia itself, imposed on normal rats, appears to have a dual effect, stimulating insulin signalling in white adipose tissue, whilst decreasing it in liver and muscle. The underlying mechanism of these differential effects may be related to the ability of hyperinsulinaemia to increase mTOR/p70 S6K pathway activity and IRS-1/2 serine phosphorylation in a tissue-specific fashion. In addition, we demonstrated that inhibition of the mTOR pathway with rapamycin can prevent insulin resistance caused by chronic hyperinsulinaemia in liver and muscle. These findings support the hypothesis that defective and tissue-selective insulin action contributes to the insulin resistance observed in hyperinsulinaemic states.
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Affiliation(s)
- M Ueno
- Department of Internal Medicine, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
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Strålfors P. Chapter 8 Insulin Signaling and Caveolae. CAVEOLAE AND LIPID RAFTS: ROLES IN SIGNAL TRANSDUCTION AND THE PATHOGENESIS OF HUMAN DISEASE 2005. [DOI: 10.1016/s1569-2558(05)36008-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Mitra P, Zheng X, Czech MP. RNAi-based Analysis of CAP, Cbl, and CrkII Function in the Regulation of GLUT4 by Insulin. J Biol Chem 2004; 279:37431-5. [PMID: 15258163 DOI: 10.1074/jbc.c400180200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stimulation of glucose transport by insulin in cultured adipocytes through translocation of intracellular GLUT4 glucose transporters to the plasma membrane has been suggested to require phosphatidylinositol (PI) 3-kinase-dependent and independent mechanisms. To test the involvement of a PI 3-kinase-independent pathway leading to activation of the TC10 GTPase, the putative intermediates CAP, c-Cbl, Cbl-b, and CrkII were selectively depleted in 3T3-L1 adipocytes using highly efficient small interfering (si) RNAs. Simultaneous depletion of the ubiquitination factors c-Cbl plus Cbl-b in cultured adipocytes had the expected effect of delaying dephosphorylation of EGF receptors upon removal of EGF. However, siRNA-mediated gene silencing of both Cbl isoforms or CAP or CrkII in these cells failed to attenuate insulin-stimulated deoxyglucose transport or Myc-tagged GLUT4-GFP translocation at either sub-maximal or maximal concentrations of insulin. The dose-response relationship for insulin stimulation of deoxyglucose transport in primary adipocytes derived from c-Cbl knock-out mice was also identical to insulin action on adipocytes from wild type mice. These data are consistent with the hypothesis that CAP, Cbl iso-forms, and CrkII are not required components of insulin signaling to GLUT4 transporters.
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Affiliation(s)
- Prasenjit Mitra
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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Brozinick JT, Hawkins ED, Strawbridge AB, Elmendorf JS. Disruption of cortical actin in skeletal muscle demonstrates an essential role of the cytoskeleton in glucose transporter 4 translocation in insulin-sensitive tissues. J Biol Chem 2004; 279:40699-706. [PMID: 15247264 PMCID: PMC2409066 DOI: 10.1074/jbc.m402697200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Cell culture work suggests that signaling to polymerize cortical filamentous actin (F-actin) represents a required pathway for the optimal redistribution of the insulin-responsive glucose transporter, GLUT4, to the plasma membrane. Recent in vitro study further suggests that the actin-regulatory neural Wiskott-Aldrich syndrome protein (N-WASP) mediates the effect of insulin on the actin filament network. Here we tested whether similar cytoskeletal mechanics are essential for insulin-regulated glucose transport in isolated rat epitrochlearis skeletal muscle. Microscopic analysis revealed that cortical F-actin is markedly diminished in muscle exposed to latrunculin B. Depolymerization of cortical F-actin with latrunculin B caused a time- and concentration-dependent decline in 2-deoxyglucose transport. The loss of cortical F-actin and glucose transport was paralleled by a decline in insulin-stimulated GLUT4 translocation, as assessed by photolabeling of cell surface GLUT4 with Bio-LC-ATB-BMPA. Although latrunculin B impaired insulin-stimulated GLUT4 translocation and glucose transport, activation of phosphatidylinositol 3-kinase and Akt by insulin was not rendered ineffective. In contrast, the ability of insulin to elicit the cortical F-actin localization of N-WASP was abrogated. These data provide the first evidence that actin cytoskeletal mechanics are an essential feature of the glucose transport process in intact skeletal muscle. Furthermore, these findings support a distal actin-based role for N-WASP in insulin action in vivo.
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Alcazar O, Ho RC, Fujii N, Goodyear LJ. cDNA cloning and functional characterization of a novel splice variant of c-Cbl-associated protein from mouse skeletal muscle. Biochem Biophys Res Commun 2004; 317:285-93. [PMID: 15047181 DOI: 10.1016/j.bbrc.2004.03.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Indexed: 11/30/2022]
Abstract
c-Cbl-associated protein (CAP) is an SH3-containing adapter protein that binds to the proto-oncogene c-Cbl. Recent work suggests that signaling through these molecules is involved in the regulation of insulin-stimulated glucose uptake in 3T3-L1 adipocytes. Skeletal muscle is the major site of insulin-stimulated glucose disposal but there have been no reports of CAP function in this tissue. Using RT-PCR of mouse skeletal muscle RNA, we discovered a novel splice variant of CAP (CAPSM; GenBank Accession No. AF521593) that is different from the adipocyte form by inclusion of a novel 168 bp fragment. This fragment encodes a peptide sequence that shows very high similarity with exon 25 of the human homologue of CAP (SORBS1). To understand the function of CAPSM in glucose uptake regulation, L6 myotubes were transfected with either CAPSM or a truncated CAPSM devoid of all three SH3-binding domains (CAPDeltaSH3), which prevents CAP association with c-Cbl. Transfection with CAPDeltaSH3 decreased insulin-stimulated 2-deoxyglucose (2-DG) uptake and reduced c-Cbl phosphorylation. In contrast, transfection of L6 myotubes with CAPDeltaSH3 had no effect on dinitrophenol (DNP)- or hypoxia-stimulated glucose uptake, stimuli that work through insulin-independent mechanisms for the regulation of glucose uptake. These data demonstrate the existence of a novel CAP isoform expressed in skeletal muscle, and suggest the involvement of the CAP/Cbl pathway in the regulation of insulin-stimulated glucose uptake in L6 myotubes.
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Affiliation(s)
- Oscar Alcazar
- The Research Division, Joslin Diabetes Center and Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02215, USA
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JeBailey L, Rudich A, Huang X, Di Ciano-Oliveira C, Kapus A, Klip A. Skeletal muscle cells and adipocytes differ in their reliance on TC10 and Rac for insulin-induced actin remodeling. Mol Endocrinol 2003; 18:359-72. [PMID: 14615606 DOI: 10.1210/me.2003-0294] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Insulin causes distinct cortical actin remodeling in muscle and fat cells, and interfering with actin dynamics halts glucose transporter 4 (GLUT4) translocation to the membrane. Phosphatidylinositol 3-kinase (PI3-K) and the small G protein Rac govern myocyte actin remodeling, whereas TC10 alpha contributes to adipocyte actin dynamics downstream of Cbl-associated protein (CAP) and Cbl, independently of PI3-K. Given the importance of insulin action in both cell types, it is paramount to determine whether signaling pathways and actin manifestations are cell type specific. We found CAP expression and insulin-mediated Cbl phosphorylation in differentiated myotubes but not in myoblasts. Unlike adipocytes, Cbl is phosphorylated on Y774 and Y731 in myotubes. TC10 alpha and beta-transcripts are amplified by RT-PCR in muscle cells, but the endogenous proteins are barely detectable using two unrelated antibodies. TC10 alpha transfected into myoblasts is activated by insulin despite the lack of CAP expression and Cbl phosphorylation. Moreover, dominant-negative TC10 alpha mutants do not prevent insulin-induced actin remodeling in either myoblasts or myotubes and do not interfere with insulin-mediated recruitment of c-myc epitope-tagged GLUT4 to the cell surface. In contrast to TC10 alpha, endogenous Rac is readily detectable in both muscle cells and adipocytes and binds GTP after insulin in a PI3-K-dependent manner. These data suggest that whereas individual components of the CAP to TC10 pathway are regulated by insulin, a functional TC10-dependent signaling pathway leading to actin remodeling and GLUT4 translocation may not operate in myocytes, as it does in adipocytes.
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Affiliation(s)
- Lellean JeBailey
- Programme in Cell Biology, Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G 1X8.
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