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Dos Reis Araujo T, Alves BL, Dos Santos LMB, Gonçalves LM, Carneiro EM. Association between protein undernutrition and diabetes: Molecular implications in the reduction of insulin secretion. Rev Endocr Metab Disord 2024; 25:259-278. [PMID: 38048021 DOI: 10.1007/s11154-023-09856-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/20/2023] [Indexed: 12/05/2023]
Abstract
Undernutrition is still a recurring nutritional problem in low and middle-income countries. It is directly associated with the social and economic sphere, but it can also negatively impact the health of the population. In this sense, it is believed that undernourished individuals may be more susceptible to the development of non-communicable diseases, such as diabetes mellitus, throughout life. This hypothesis was postulated and confirmed until today by several studies that demonstrate that experimental models submitted to protein undernutrition present alterations in glycemic homeostasis linked, in part, to the reduction of insulin secretion. Therefore, understanding the changes that lead to a reduction in the secretion of this hormone is essential to prevent the development of diabetes in undernourished individuals. This narrative review aims to describe the main molecular changes already characterized in pancreatic β cells that will contribute to the reduction of insulin secretion in protein undernutrition. So, it will provide new perspectives and targets for postulation and action of therapeutic strategies to improve glycemic homeostasis during this nutritional deficiency.
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Affiliation(s)
- Thiago Dos Reis Araujo
- Obesity and Comorbidities Research Center (OCRC), Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Carl Von Linnaeus Bloco Z, Campinas, SP, Cep: 13083-864, Brazil
| | - Bruna Lourençoni Alves
- Obesity and Comorbidities Research Center (OCRC), Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Carl Von Linnaeus Bloco Z, Campinas, SP, Cep: 13083-864, Brazil
| | - Lohanna Monali Barreto Dos Santos
- Obesity and Comorbidities Research Center (OCRC), Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Carl Von Linnaeus Bloco Z, Campinas, SP, Cep: 13083-864, Brazil
| | - Luciana Mateus Gonçalves
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Everardo Magalhães Carneiro
- Obesity and Comorbidities Research Center (OCRC), Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Carl Von Linnaeus Bloco Z, Campinas, SP, Cep: 13083-864, Brazil.
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Israeli T, Riahi Y, Garzon P, Louzada RA, Werneck-de-Castro JP, Blandino-Rosano M, Yeroslaviz-Stolper R, Kadosh L, Tornovsky-Babeay S, Hacker G, Israeli N, Agmon O, Tirosh B, Cerasi E, Bernal-Mizrachi E, Leibowitz G. Nutrient Sensor mTORC1 Regulates Insulin Secretion by Modulating β-Cell Autophagy. Diabetes 2022; 71:453-469. [PMID: 34862201 PMCID: PMC8893949 DOI: 10.2337/db21-0281] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 11/30/2021] [Indexed: 01/23/2023]
Abstract
The dynamic regulation of autophagy in β-cells by cycles of fasting-feeding and its effects on insulin secretion are unknown. In β-cells, mechanistic target of rapamycin complex 1 (mTORC1) is inhibited while fasting and is rapidly stimulated during refeeding by a single amino acid, leucine, and glucose. Stimulation of mTORC1 by nutrients inhibited the autophagy initiator ULK1 and the transcription factor TFEB, thereby preventing autophagy when β-cells were continuously exposed to nutrients. Inhibition of mTORC1 by Raptor knockout mimicked the effects of fasting and stimulated autophagy while inhibiting insulin secretion, whereas moderate inhibition of autophagy under these conditions rescued insulin secretion. These results show that mTORC1 regulates insulin secretion through modulation of autophagy under different nutritional situations. In the fasting state, autophagy is regulated in an mTORC1-dependent manner, and its stimulation is required to keep insulin levels low, thereby preventing hypoglycemia. Reciprocally, stimulation of mTORC1 by elevated leucine and glucose, which is common in obesity, may promote hyperinsulinemia by inhibiting autophagy.
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Affiliation(s)
- Tal Israeli
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Yael Riahi
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Perla Garzon
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ruy Andrade Louzada
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Joao Pedro Werneck-de-Castro
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Manuel Blandino-Rosano
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Roni Yeroslaviz-Stolper
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Liat Kadosh
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Sharona Tornovsky-Babeay
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Gilad Hacker
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Nitzan Israeli
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Orly Agmon
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Boaz Tirosh
- Stress Signaling Laboratory, School of Pharmacy, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Erol Cerasi
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Gil Leibowitz
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- Corresponding author: Gil Leibowitz,
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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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Gao X, Hou R, Li X, Qiu XH, Luo HH, Liu SL, Fang ZZ. The Association Between Leucine and Diabetic Nephropathy in Different Gender: A Cross-Sectional Study in Chinese Patients With Type 2 Diabetes. Front Endocrinol (Lausanne) 2020; 11:619422. [PMID: 33633688 PMCID: PMC7900620 DOI: 10.3389/fendo.2020.619422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/14/2020] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE This study aimed to evaluate how leucine are associated with diabetic nephropathy (DN) in type 2 diabetes (T2D) patients and the gender difference of this association. METHODS We retrieved 1,031 consecutive patients with T2D who meet the inclusion and exclusion criteria from the same tertiary care center and extracted clinical information from electronic medical record. Plasma leucine was measured by liquid chromatography-mass spectrometer. Restricted cubic spline (RCS) was conducted to examine potential non-linear relationship between leucine and the risk of DN. Logistic regression was used to obtain odds ratio (OR) and confidence interval (CI). Additive interaction was used to estimate the interaction effect between leucine and gender for DN. RESULTS We found there was a negative correlation between leucine and the risk of DN. After stratifying all patients by gender, this relationship only remained significant in women (OR:0.57, CI:0.41-0.79). CONCLUSIONS In conclusion, T2D patients with high levels of leucine have a lower risk of developing DN in female.
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Affiliation(s)
- Xiaoqian Gao
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Ruiqin Hou
- Department of Blood Transfusion, Peking University People’s Hospital, Beijing, China
| | - Xin Li
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Xing-Hua Qiu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Hui-Huan Luo
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Sheng-Lin Liu
- Department of Laboratory Center of Tianjin Xiqing Hospital, Tianjin, China
- *Correspondence: Sheng-Lin Liu, ; Zhong-Ze Fang,
| | - Zhong-Ze Fang
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China
- Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China
- *Correspondence: Sheng-Lin Liu, ; Zhong-Ze Fang,
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Zhang J, Xu W, Han H, Zhang L, Wang T. Dietary Leucine Supplementation Restores Serum Glucose Levels, and Modifying Hepatic Gene Expression Related to the Insulin Signal Pathway in IUGR Piglets. Animals (Basel) 2019; 9:ani9121138. [PMID: 31847151 PMCID: PMC6941017 DOI: 10.3390/ani9121138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/09/2019] [Accepted: 12/11/2019] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Intrauterine malnutrition may compromise the size and structure of fetal organs and tissues, which leads to lower birth weight and a slower rate of growth after weaning. Intrauterine growth restriction/retardation (IUGR) impairs pancreas function, resulting in the decreased glucose levels in serum. Leucine, one of branched chain amino acids, is an essential amino acid and the substrate of protein synthesis. Leucine also acts as a major regulator of hormone signal transduction, like insulin. Dietary branched chain amino acids or leucine have beneficial effects on the glucose metabolism and glycogen synthesis of muscle. Leucine supplementation improves the insulin sensitivity in liver and muscle and then influences the systemic glucose homeostasis. However, it is still unclear whether leucine supplementation would alter insulin sensitivity in IUGR neonatal piglets. Our results showed that dietary leucine supplementation restored serum glucose concentrations, increased insulin and creatinine concentrations, and enhanced protein kinase adenosine monophosphate-activated γ 3-subunit and glucose transporter type 2 expression. These findings suggest that leucine might play a positive role in hepatic lipid metabolism and glucose metabolism in IUGR. Abstract This study aimed to investigate the effects of leucine with different levels on the insulin resistance in intrauterine growth restriction/retardation (IUGR) piglets. Thirty-two weaned piglets were arranged in a 2 × 2 factorial design and four treatments (n = 8) were as follow: (1) normal weaned piglets fed a basal diet (CONT), (2) IUGR weaned piglets fed a basal diet (IUGR), (3) normal weaned piglets fed a basal diet with the addition of 0.35% l-leucine (C-LEU), and (4) IUGR fed a basal diet with the addition of 0.35% l-leucine (I-LEU) for a 21-days trial. The results showed that compared to the IUGR group, the I-LEU group had higher final body weight and body weight gain, higher serum glucose concentrations, and higher serum insulin concentrations (p < 0.05). The gene expression of phosphatidylinositol 3-kinase p110 gamma, protein kinase adenosine monophosphate-activated γ 3-subunit, glycogen synthase kinase-3 alpha, and glucose transporter type 2 were increased in the I-LEU group as compared to the IUGR group (p < 0.05). It was concluded that dietary leucine supplementation restored serum glucose concentrations, increased insulin and creatinine concentrations, and enhanced protein kinase adenosine monophosphate-activated γ 3-subunit and glucose transporter type 2 expression, suggesting that leucine might play a positive role in hepatic lipid metabolism and glucose metabolism in IUGR.
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Affiliation(s)
| | | | | | | | - Tian Wang
- Correspondence: ; Tel./Fax: +86-25-84395156
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Liang H, Mokrani A, Chisomo-Kasiya H, Ji K, Ge X, Ren M, Liu B, Xi B, Sun A. Dietary leucine affects glucose metabolism and lipogenesis involved in TOR/PI3K/Akt signaling pathway for juvenile blunt snout bream Megalobrama amblycephala. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:719-732. [PMID: 30632024 DOI: 10.1007/s10695-018-0594-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 11/26/2018] [Indexed: 05/12/2023]
Abstract
The present study evaluated the mechanisms governing insulin signaling, glucose metabolism, and lipogenesis in juvenile fish fed with different dietary leucine levels. Fish were fed six practical diets with graded leucine levels ranging from 0.90 to 2.94% of dry basis for 8 weeks. The trial results showed that, compared to the control group (0.90%), optimal dietary leucine level (1.72%) resulted in the up-regulation of mRNA expression related to insulin signaling pathway, including target of rapamycin (TOR), insulin receptor substrate 1 (IRS-1), phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt). However, an excessive leucine level (2.94%) led to protein S6 kinase 1 (S6K1) overexpression and inhibited TOR, IRS-1, PI3K, and Akt mRNA expressions. The protein level of TOR, S6K1, IRS-1, PI3K, and Akt showed a similar result with mRNA level of these genes. Optimal dietary leucine level (1.72%) significantly improved plasma insulin content, while high level of leucine showed an inhibiting phenomenon. Optimal dietary leucine level (1.72%) could reduce plasma glucose by enhancing the ability of glycometabolism including improving glucose transporter 2 (GLUT2), glucokinase (GK) expressions and down-regulating phosphoenolpyruvate carboxykinase (PEPCK) expression. While an excessive leucine level (2.94%) resulted in high plasma glucose by inhibiting the ability of glycometabolism including lowering GLUT2 and GK expressions, and improving glucose-6-phosphatase (G6Pase) and PEPCK expressions. The relative expressions of pyruvate kinase (PK) and glycogen synthase (GS) were not significantly affected by dietary leucine levels. Dietary leucine level of 1.33% could improve plasma triglyceride content (TG) by enhancing lipogenesis including improving sterol-response element-binding protein 1 (SREBP1), fatty acid synthase (FAS), acetyl CoA carboxylase (ACC), and glucose-6-phosphate dehydrogenase (G6PDH) expressions compared to the control group (0.90%). Total cholesterol (TC) was not significantly affected by dietary leucine levels. The present results indicate that optimal leucine level could improve glycolysis and fatty acid synthesis through improving insulin sensitivity in juvenile blunt snout bream. However, excessive dietary leucine level resulted in high plasma glucose, which led to insulin resistance by inhibiting the gene expressions of insulin signaling pathway and activating gluconeogenesis-related gene expression.
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Affiliation(s)
- Hualiang Liang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | - Ahmed Mokrani
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | | | - Ke Ji
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | - Xianping Ge
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China.
| | - Mingchun Ren
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China.
| | - Bo Liu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China
| | - Bingwen Xi
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China
| | - Ajun Sun
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China
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Offspring of Mice Exposed to a Low-Protein Diet in Utero Demonstrate Changes in mTOR Signaling in Pancreatic Islets of Langerhans, Associated with Altered Glucagon and Insulin Expression and a Lower β-Cell Mass. Nutrients 2019; 11:nu11030605. [PMID: 30871106 PMCID: PMC6471519 DOI: 10.3390/nu11030605] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 02/07/2023] Open
Abstract
Low birth weight is a risk factor for gestational and type 2 diabetes (T2D). Since mammalian target of rapamycin (mTOR) controls pancreatic β-cell mass and hormone release, we hypothesized that nutritional insult in utero might permanently alter mTOR signaling. Mice were fed a low-protein (LP, 8%) or control (C, 20%) diet throughout pregnancy, and offspring examined until 130 days age. Mice receiving LP were born 12% smaller and β-cell mass was significantly reduced throughout life. Islet mTOR levels were lower in LP-exposed mice and localized predominantly to α-rather than β-cells. Incubation of isolated mouse islets with rapamycin significantly reduced cell proliferation while increasing apoptosis. mRNA levels for mTORC complex genes mTOR, Rictor and Raptor were elevated at 7 days in LP mice, as were the mTOR and Raptor proteins. Proglucagon gene expression was similarly increased, but not insulin or the immune/metabolic defense protein STING. In human and mouse pancreas STING was strongly associated with islet β-cells. Results support long-term changes in islet mTOR signaling in response to nutritional insult in utero, with altered expression of glucagon and insulin and a reduced β-cell mass. This may contribute to an increased risk of gestational or type 2 diabetes.
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Viana ALM, Doriguetto AC, Viana OMMS, Ruela ALM, Freitas JTJ, Souto BEM, de Araújo MB, de Araújo Paula FB. Pharmacokinetics and pharmacodynamics of glimepiride polymorphs. Int J Pharm 2018; 553:272-280. [DOI: 10.1016/j.ijpharm.2018.10.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 10/28/2022]
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Shi YG, Zhang N, Guo QQ, Guan HN, Ikeda S, Guo CH, Piekoszewski W, Kalenik TK, Motkina E. Effects of casein non-phosphopeptide on the development of rat muscle analyzed using computed tomography scanning technology. Food Funct 2018; 9:5805-5812. [PMID: 30352111 DOI: 10.1039/c8fo01405a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of casein non-phosphopeptide (CNPP) on the muscle development of healthy rats and selected blood hormones levels were investigated. CT technology and the ELISA kit were employed to detect the cross-sectional area of each muscle group and blood hormone levels, respectively. The cross-sectional area of the trunk and lower limb muscles of resistance exercise group (REG) rats that were administered a high daily dose of CNPP for 50 days increased more significantly than that of the blank group rats, no exercise group (NEG) rats administered with the same daily dose of CNPP, and REG rats administered with the same daily dose of lactalbumin (P < 0.05).The more enhanced development of trunk and lower limb muscles in CNPP-administered REG rats was associated with a higher blood level of insulin, while no clear trends in blood levels of growth hormone and testosterone were observed. The present results have demonstrated that a combination of physical exercise and diet supplementation with CNPP can synergistically improve muscle mass.
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Affiliation(s)
- Yan-Guo Shi
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, 36# No. 138, Tongda Street, Daoli District, Harbin 150076, P R China.
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Guo L, Liang Z, Zheng C, Liu B, Yin Q, Cao Y, Yao J. Leucine Affects α-Amylase Synthesis through PI3K/Akt-mTOR Signaling Pathways in Pancreatic Acinar Cells of Dairy Calves. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:5149-5156. [PMID: 29733580 DOI: 10.1021/acs.jafc.8b01111] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dietary nutrient utilization, particularly starch, is potentially limited by digestion in dairy cow small intestine because of shortage of α-amylase. Leucine acts as an effective signal molecular in the mTOR signaling pathway, which regulates a series of biological processes, especially protein synthesis. It has been reported that leucine could affect α-amylase synthesis and secretion in ruminant pancreas, but mechanisms have not been elaborated. In this study, pancreatic acinar (PA) cells were used as a model to determine the cellular signal of leucine influence on α-amylase synthesis. PA cells were isolated from newborn Holstein dairy bull calves and cultured in Dulbecco's modifed Eagle's medium/nutrient mixture F12 liquid media containing four leucine treatments (0, 0.23, 0.45, and 0.90 mM, respectively), following α-amylase activity, zymogen granule, and signal pathway factor expression detection. Rapamycin, a specific inhibitor of mTOR, was also applied to PA cells. Results showed that leucine increased ( p < 0.05) synthesis of α-amylase as well as phosphorylation of PI3K, Akt, mTOR, and S6K1 while reduced ( p < 0.05) GCN2 expression. Inhibition of mTOR signaling downregulated the α-amylase synthesis. In addition, the extracellular leucine dosage significantly influenced intracellular metabolism of isoleucine ( p < 0.05). Overall, leucine regulates α-amylase synthesis through promoting the PI3K/Akt-mTOR pathway and reducing the GCN2 pathway in PA cells of dairy calves. These pathways form the signaling network that controls the protein synthesis and metabolism. It would be of great interest in future studies to explore the function of leucine in ruminant nutrition.
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Affiliation(s)
- Long Guo
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Ziqi Liang
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Chen Zheng
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Baolong Liu
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Qingyan Yin
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Yangchun Cao
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Junhu Yao
- College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
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Gannon NP, Schnuck JK, Vaughan RA. BCAA Metabolism and Insulin Sensitivity - Dysregulated by Metabolic Status? Mol Nutr Food Res 2018; 62:e1700756. [PMID: 29377510 DOI: 10.1002/mnfr.201700756] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/29/2017] [Indexed: 12/18/2022]
Abstract
Branched-chain amino acids (BCAAs) appear to influence several synthetic and catabolic cellular signaling cascades leading to altered phenotypes in mammals. BCAAs are most notably known to increase protein synthesis through modulating protein translation, explaining their appeal to resistance and endurance athletes for muscle hypertrophy, expedited recovery, and preservation of lean body mass. In addition to anabolic effects, BCAAs may increase mitochondrial content in skeletal muscle and adipocytes, possibly enhancing oxidative capacity. However, elevated circulating BCAA levels have been correlated with severity of insulin resistance. It is hypothesized that elevated circulating BCAAs observed in insulin resistance may result from dysregulated BCAA degradation. This review summarizes original reports that investigated the ability of BCAAs to alter glucose uptake in consequential cell types and experimental models. The review also discusses the interplay of BCAAs with other metabolic factors, and the role of excess lipid (and possibly energy excess) in the dysregulation of BCAA catabolism. Lastly, this article provides a working hypothesis of the mechanism(s) by which lipids may contribute to altered BCAA catabolism, which often accompanies metabolic disease.
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Affiliation(s)
| | - Jamie K Schnuck
- School of Medicine, Medical College of Wisconsin, Milwaukee, WI
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, NC
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Diet-induced glucose homeostasis dysregulation is enhanced by taurine supplementation in ovariectomized mice. Amino Acids 2017; 50:469-477. [PMID: 29282544 DOI: 10.1007/s00726-017-2533-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 12/19/2017] [Indexed: 01/02/2023]
Abstract
Low levels of estrogens are associated with obesity-related comorbidities. Mice with lower levels of estrogens are thereby more sensitive to the effects of a high-fat-diet (HFD) for the development of glucose intolerance and insulin resistance. Studies in vivo have demonstrated that taurine (TAU) supplementation prevents glucose and insulin resistance. Thus, we aimed to investigate the potential beneficial effects of TAU supplementation on glucose homeostasis of mice with low levels of estrogens fed with a HFD. 3-month-old female C57BL/6J mice underwent bilateral ovariectomy (OVX). After 1 week of recovery, mice were divided into 4 groups and either received: a standard chow diet (OVXC), chow diet plus drinking water enriched with 3% of TAU (OVXCT), HFD (OVXH), and HFD plus supplementation of TAU (OVXHT) for 14 weeks. Exposure to the HFD increased adiposity and plasma levels of glucose and insulin. Contrary to our prediction, the addition of TAU enhanced the deleterious effects of the HFD. Glucose and insulin tolerance tests (ipGTT and ipITT) indicated that mice maintained on the HFD + TAU had worse glucose intolerance and insulin resistance that was linked to lower insulin signaling in skeletal muscle and liver. Insulin secretion of isolated pancreatic islets of OVXH mice was higher than OVXC, and the addition of TAU associated with a HFD did not modulate insulin secretion, suggesting a failure of pancreatic β cells of OVXHT mice. These results suggest that despite the beneficial reports of TAU, it should be used cautiously in situations where the levels of estrogens are low.
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Horiuchi M, Takeda T, Takanashi H, Ozaki-Masuzawa Y, Taguchi Y, Toyoshima Y, Otani L, Kato H, Sone-Yonezawa M, Hakuno F, Takahashi SI, Takenaka A. Branched-chain amino acid supplementation restores reduced insulinotropic activity of a low-protein diet through the vagus nerve in rats. Nutr Metab (Lond) 2017; 14:59. [PMID: 28932254 PMCID: PMC5602936 DOI: 10.1186/s12986-017-0215-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/05/2017] [Indexed: 02/09/2023] Open
Abstract
Background Previously, we reported that a low-protein diet significantly reduced insulin secretion in response to feeding within 1 h in rats, suggesting that the insulinotropic effect of dietary protein plays an important role in maintaining normal insulin release. The current study aimed to elucidate whether deficiency of certain amino acids could diminish the insulinotropic activity and to investigate whether reduced insulin secretion in response to a low-protein diet is restored by supplementation with certain amino acids. Methods First, we fed male Wistar rats (5–6 rats per group) with diets deficient in every single amino acid or three branched-chain amino acids (BCAAs); within 1–2 h after the onset of feeding, we measured the plasma insulin levels by using an enzyme-linked immunosorbent assay (ELISA). As insulin secretion was reduced in BCAA-deficient groups, we fed low-protein diets supplemented with BCAAs to assess whether the reduced insulin secretion was restored. In addition, we treated the pancreatic beta cell line MIN6 with BCAAs to investigate the direct insulinotropic activity on beta cells. Lastly, we investigated the effect of the three BCAAs on sham-operated or vagotomized rats to assess involvement of the vagus nerve in restoration of the insulinotropic activity. Results Feeding a low-protein diet reduced essential amino acid concentrations in the plasma during an absorptive state, suggesting that reduced plasma amino acid levels can be an initial signal of protein deficiency. In normal rats, insulin secretion was reduced when leucine, valine, or three BCAAs were deficient. Insulin secretion was restored to normal levels by supplementation of the low-protein diet with three BCAAs, but not by supplementation with any single BCAA. In MIN6 cells, each BCAA alone stimulated insulin secretion but the three BCAAs did not show a synergistic stimulatory effect. The three BCAAs showed a synergistic stimulatory effect in sham-operated rats but failed to stimulate insulin secretion in vagotomized rats. Conclusions Leucine and valine play a role in maintaining normal insulin release by directly stimulating beta cells, and supplementation with the three BCAAs is sufficient to compensate for the reduced insulinotropic activity of the low-protein diet, through the vagus nerve.
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Affiliation(s)
- Mami Horiuchi
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Tomoya Takeda
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Hiroyuki Takanashi
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Yori Ozaki-Masuzawa
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kanagawa, Japan.,Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, Kanagawa, Japan
| | - Yusuke Taguchi
- Institute for Advanced Medical Sciences, Nippon Medical School, Kanagawa, Japan
| | - Yuka Toyoshima
- Institute for Advanced Medical Sciences, Nippon Medical School, Kanagawa, Japan
| | - Lila Otani
- Corporate Sponsored Research Program "Food for Life" Organization for Interdisciplinary Research Projects, The University of Tokyo, Tokyo, Japan
| | - Hisanori Kato
- Corporate Sponsored Research Program "Food for Life" Organization for Interdisciplinary Research Projects, The University of Tokyo, Tokyo, Japan
| | - Meri Sone-Yonezawa
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Fumihiko Hakuno
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shin-Ichiro Takahashi
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Asako Takenaka
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kanagawa, Japan
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14
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Borck PC, Batista TM, Vettorazzi JF, Camargo RL, Boschero AC, Vieira E, Carneiro EM. Protein malnutrition after weaning disrupts peripheral clock and daily insulin secretion in mice. J Nutr Biochem 2017; 50:54-65. [PMID: 29032081 DOI: 10.1016/j.jnutbio.2017.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 07/13/2017] [Accepted: 08/28/2017] [Indexed: 12/22/2022]
Abstract
Changes in nutritional state may alter circadian rhythms through alterations in expression of clock genes. Protein deficiency has a profound effect on body metabolism, but the effect of this nutrient restriction after weaning on biological clock has not been explored. Thus, this study aims to investigate whether the protein restriction affects the daily oscillation in the behavior and metabolic rhythms, as well as expression of clock genes in peripheral tissues. Male C57BL/6 J mice, after weaning, were fed a normal-protein (NP) diet or a low-protein (LP) diet for 8 weeks. Mice fed an LP diet did not show difference in locomotor activity and energy expenditure, but the food intake was increased, with parallel increased expression of the orexigenic neuropeptide Npy and disruption of the anorexigenic Pomc oscillatory pattern in the hypothalamus. LP mice showed disruption in the daily rhythmic patterns of plasma glucose, triglycerides and insulin. Also, the rhythmic expression of clock genes in peripheral tissues and pancreatic islets was altered in LP mice. In pancreatic islets, the disruption of clock genes was followed by impairment of daily glucose-stimulated insulin secretion and the expression of genes involved in exocytosis. Pharmacological activation of REV-ERBα could not restore the insulin secretion in LP mice. The present study demonstrates that protein restriction, leading to development of malnutrition, alters the peripheral clock and metabolic outputs, suggesting that this nutrient provides important entraining cues to regulate the daily fluctuation of biological clock.
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MESH Headings
- Adipose Tissue, White/metabolism
- Animals
- Biological Clocks
- CLOCK Proteins/genetics
- CLOCK Proteins/metabolism
- Diet, Protein-Restricted/adverse effects
- Gene Expression Regulation, Developmental/drug effects
- Glycine/analogs & derivatives
- Glycine/pharmacology
- Hypothalamus/metabolism
- Insulin/genetics
- Insulin/metabolism
- Insulin Secretion
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Isoquinolines/pharmacology
- Liver/metabolism
- Male
- Mice, Inbred C57BL
- Muscle, Skeletal/metabolism
- Neurons/metabolism
- Neuropeptide Y/genetics
- Neuropeptide Y/metabolism
- Nuclear Receptor Subfamily 1, Group D, Member 1/agonists
- Nuclear Receptor Subfamily 1, Group D, Member 1/antagonists & inhibitors
- Nuclear Receptor Subfamily 1, Group D, Member 1/metabolism
- Organ Specificity
- Pro-Opiomelanocortin/genetics
- Pro-Opiomelanocortin/metabolism
- Protein Deficiency/etiology
- Protein Deficiency/physiopathology
- Random Allocation
- Thiophenes/pharmacology
- Weaning
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Affiliation(s)
- Patricia Cristine Borck
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
| | - Thiago Martins Batista
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
| | - Jean Franciesco Vettorazzi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
| | - Rafael Ludemann Camargo
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
| | - Antonio Carlos Boschero
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
| | - Elaine Vieira
- Postgraduate Program on Physical Education, Universidade Católica de Brasília-UCB, Brasília, DF, Brazil.
| | - Everardo Magalhães Carneiro
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
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15
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Cappelli APG, Zoppi CC, Silveira LR, Batista TM, Paula FM, da Silva PMR, Rafacho A, Barbosa-Sampaio HC, Boschero AC, Carneiro EM. Reduced glucose-induced insulin secretion in low-protein-fed rats is associated with altered pancreatic islets redox status. J Cell Physiol 2017; 233:486-496. [PMID: 28370189 DOI: 10.1002/jcp.25908] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/13/2017] [Indexed: 01/01/2023]
Abstract
In the present study, we investigated the relationship between early life protein malnutrition-induced redox imbalance, and reduced glucose-stimulated insulin secretion. After weaning, male Wistar rats were submitted to a normal-protein-diet (17%-protein, NP) or to a low-protein-diet (6%-protein, LP) for 60 days. Pancreatic islets were isolated and hydrogen peroxide (H2 O2 ), oxidized (GSSG) and reduced (GSH) glutathione content, CuZn-superoxide dismutase (SOD1), glutathione peroxidase (GPx1) and catalase (CAT) gene expression, as well as enzymatic antioxidant activities were quantified. Islets that were pre-incubated with H2 O2 and/or N-acetylcysteine, were subsequently incubated with glucose for insulin secretion measurement. Protein malnutrition increased CAT mRNA content by 100%. LP group SOD1 and CAT activities were 50% increased and reduced, respectively. H2 O2 production was more than 50% increased whereas GSH/GSSG ratio was near 60% lower in LP group. Insulin secretion was, in most conditions, approximately 50% lower in LP rat islets. When islets were pre-incubated with H2 O2 (100 μM), and incubated with glucose (33 mM), LP rats showed significant decrease of insulin secretion. This effect was attenuated when LP islets were exposed to N-acetylcysteine.
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Affiliation(s)
- Ana Paula G Cappelli
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão (UFMA), São Luís, Maranhão, Brazil.,Department of Physiology and Biophysiology, Institute of Biomedical Sciences, University of Sao Paulo (USP), São Paulo, Brazil
| | - Claudio C Zoppi
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Leonardo R Silveira
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Thiago M Batista
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Flávia M Paula
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | - Alex Rafacho
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Department of Physiologic Sciences, Center of Biologic Sciences, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil
| | - Helena C Barbosa-Sampaio
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Antonio C Boschero
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Everardo M Carneiro
- Department of Structural and Functional Biology, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
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16
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Santos RS, Batista TM, Camargo RL, Morato PN, Borck PC, Leite NC, Kurauti MA, Wanschel ACBA, Nadal Á, Clegg DJ, Carneiro EM. Lacking of estradiol reduces insulin exocytosis from pancreatic β-cells and increases hepatic insulin degradation. Steroids 2016; 114:16-24. [PMID: 27192429 DOI: 10.1016/j.steroids.2016.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/18/2016] [Accepted: 05/11/2016] [Indexed: 01/08/2023]
Abstract
Low levels of plasma estrogens are associated with weight-gain, android fat distribution, and a high prevalence of obesity-related comorbidities such as glucose intolerance and type II diabetes. The mechanisms underlying the association between low levels of estrogens and impaired glucose homeostasis are not completely understood. To begin to test this, we used three-month-old female C57BL/6J mice that either underwent ovariectomy (OVX) or received a sham surgery (Sham), and we characterized glucose homeostasis. In a subsequent series of experiments, OVX mice received estradiol treatment (OVX+E2) or vehicle (OVX) for 6 consecutive days. As has been previously reported, lack of ovarian hormones resulted in dysregulated glucose homeostasis. To begin to explore the mechanisms by which this occurs, we characterized the impact of estrogens on insulin secretion and degradation in these mice. Insulin secretion and plasma insulin levels were lower in OVX mice. OVX mice had lower levels of pancreatic Syntaxin 1-A (Synt-1A) protein, which is involved in insulin extrusion from the pancreas. In the liver, OVX mice had higher levels of insulin-degrading enzyme (IDE) and this was associated with higher insulin clearance. Estradiol treatment improved glucose intolerance in OVX mice and restored insulin secretion, as well as normalized the protein content of pancreatic Synt-1A. The addition of estrogens to OVX mice reduced IDE protein to that of Sham mice. Our data suggest loss of ovarian estradiol following OVX led to impaired glucose homeostasis due to pancreatic β-cell dysfunction in the exocytosis of insulin, and upregulation of hepatic IDE protein content resulting in lower insulinemia, which was normalized by estradiol replacement.
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Affiliation(s)
- Roberta S Santos
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil; Biomedical Research Department, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Beverly Hills, CA, United States.
| | - Thiago M Batista
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Rafael L Camargo
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Priscila N Morato
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Patrícia C Borck
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Nayara C Leite
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Mirian A Kurauti
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Amarylis C B A Wanschel
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ángel Nadal
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Universidad Miguel Hernández de Elche, Elche, Alicante, Spain
| | - Deborah J Clegg
- Biomedical Research Department, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Beverly Hills, CA, United States
| | - Everardo M Carneiro
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, e Centro de Pesquisa em Obesidade e Comorbidades, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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17
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Effect of Oral Branched-Chain Amino Acid Supplementation Prior to Resistance Exercise on Metabolic Hormones, Plasma Amino Acids, and Serum Indices of Muscle Damage in the Recovery Period. TOP CLIN NUTR 2016. [DOI: 10.1097/tin.0000000000000085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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18
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Leucine-induced anabolic-catabolism: two sides of the same coin. Amino Acids 2015; 48:321-36. [DOI: 10.1007/s00726-015-2109-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/28/2015] [Indexed: 10/22/2022]
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19
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Reviewing the Effects of L-Leucine Supplementation in the Regulation of Food Intake, Energy Balance, and Glucose Homeostasis. Nutrients 2015; 7:3914-37. [PMID: 26007339 PMCID: PMC4446786 DOI: 10.3390/nu7053914] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 04/30/2015] [Accepted: 05/12/2015] [Indexed: 12/18/2022] Open
Abstract
Leucine is a well-known activator of the mammalian target of rapamycin (mTOR). Because mTOR signaling regulates several aspects of metabolism, the potential of leucine as a dietary supplement for treating obesity and diabetes mellitus has been investigated. The objective of the present review was to summarize and discuss the available evidence regarding the mechanisms and the effects of leucine supplementation on the regulation of food intake, energy balance, and glucose homeostasis. Based on the available evidence, we conclude that although central leucine injection decreases food intake, this effect is not well reproduced when leucine is provided as a dietary supplement. Consequently, no robust evidence indicates that oral leucine supplementation significantly affects food intake, although several studies have shown that leucine supplementation may help to decrease body adiposity in specific conditions. However, more studies are necessary to assess the effects of leucine supplementation in already-obese subjects. Finally, although several studies have found that leucine supplementation improves glucose homeostasis, the underlying mechanisms involved in these potential beneficial effects remain unknown and may be partially dependent on weight loss.
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20
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Ribeiro CB, Christofoletti DC, Pezolato VA, de Cássia Marqueti Durigan R, Prestes J, Tibana RA, Pereira ECL, de Sousa Neto IV, Durigan JLQ, da Silva CA. Leucine minimizes denervation-induced skeletal muscle atrophy of rats through akt/mtor signaling pathways. Front Physiol 2015; 6:73. [PMID: 25852565 PMCID: PMC4364154 DOI: 10.3389/fphys.2015.00073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/20/2015] [Indexed: 11/20/2022] Open
Abstract
The aim of the present study was to evaluate the effect of leucine treatment (0.30 mM) on muscle weight and signaling of myoproteins related to synthesis and degradation pathways of soleus muscle following seven days of complete sciatic nerve lesion. Wistar rats (n = 24) of 3–4 months of age (192 ± 23 g) were used. The animals were randomly distributed into four experimental groups (n = 6/group): control, treated with leucine (L), denervated (D) and denervated treated with leucine (DL). Dependent measures were proteins levels of AKT, AMPK, mTOR, and ACC performed by Western blot. Leucine induced a reduction in the phosphorylation of AMPK (p < 0.05) by 16% in the L and by 68% in the DL groups as compared with control group. Denervation increased AMPK by 24% in the D group as compared with the control group (p < 0.05). AKT was also modulated by denervation and leucine treatment, highlighted by the elevation of AKT phosphorylation in the D (65%), L (98%) and DL (146%) groups as compared with the control group (p < 0.05). AKT phosphorylation was 49% higher in the D group as compared with the DL group. Furthermore, denervation decreased mTOR phosphorylation by 29% in the D group as compared with the control group. However, leucine treatment induced an increase of 49% in the phosphorylation of mTOR in the L group as compared with the control group, and an increase of 154% in the DL as compared with the D group (p < 0.05). ACC phosphorylation was 20% greater in the D group than the control group. Furthermore, ACC in the soleus was 22% lower in the in the L group and 50% lower in the DL group than the respective control group (p < 0.05). In conclusion, leucine treatment minimized the deleterious effects of denervation on rat soleus muscle by increasing anabolic (AKT and mTOR) and decreasing catabolic (AMPK) pathways. These results may be interesting for muscle recovery following acute denervation, which may contribute to musculoskeletal rehabilitation after denervation.
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Affiliation(s)
- Carolina B Ribeiro
- Programa de Pós-graduação em Ciências do Movimento Humano, Methodist University of Piracicaba, UNIMEP Piracicaba, Brazil
| | - Daiane C Christofoletti
- Programa de Pós-graduação em Ciências do Movimento Humano, Methodist University of Piracicaba, UNIMEP Piracicaba, Brazil
| | - Vitor A Pezolato
- Programa de Pós-graduação em Ciências do Movimento Humano, Methodist University of Piracicaba, UNIMEP Piracicaba, Brazil
| | | | - Jonato Prestes
- Graduate Program of Physical Education, Catholic University of Brasília Brasilia, Brazil
| | - Ramires A Tibana
- Graduate Program of Physical Education, Catholic University of Brasília Brasilia, Brazil
| | - Elaine C L Pereira
- Graduate Program of Science and Technology of Health, University of Brasília Brasilia, Brazil
| | - Ivo V de Sousa Neto
- Graduate Program of Physical Education, Catholic University of Brasília Brasilia, Brazil
| | - João L Q Durigan
- Graduate Program of Science and Technology of Health, University of Brasília Brasilia, Brazil ; Graduate Program of Physical Education, University of Brasília Brasilia, Brazil
| | - Carlos A da Silva
- Programa de Pós-graduação em Ciências do Movimento Humano, Methodist University of Piracicaba, UNIMEP Piracicaba, Brazil
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21
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Cappelli AP, Zoppi CC, Barbosa-Sampaio HC, Costa JM, Protzek AO, Morato PN, Boschero AC, Carneiro EM. Taurine-induced insulin signalling improvement of obese malnourished mice is associated with redox balance and protein phosphatases activity modulation. Liver Int 2014; 34:771-83. [PMID: 23998525 DOI: 10.1111/liv.12291] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 07/24/2013] [Indexed: 02/13/2023]
Abstract
BACKGROUND & AIMS Obese protein malnourished mice display liver insulin resistance and taurine (TAU) seems to attenuate this effect. The association between early-life malnutrition and hepatic redox balance in diet-induced insulin resistance is unknown. We investigated TAU supplementation effects upon liver redox state and insulin signalling in obese protein malnourished mice. METHODS Weaned male C57BL-6 mice were fed a control (14% protein - C) or a protein-restricted diet (6% protein - R) for 6 weeks. Afterwards, mice received a high-fat diet (34% fat - HFD) for 8 weeks (CH - RH). Half of the HFD-mice were supplemented with TAU (5%) throughout the treatment (CHT - RHT). Body and tissues' weight, respiratory quotient (RQ), glucose tolerance and insulin sensitivity, hepatic oxidant and antioxidant markers and insulin cascade proteins were assessed. RESULTS Protein restriction leads to typical features whereas HFD was able to induce a catch-up growth in RH. HFD-groups showed higher energy intake and adiposity, lower energy expenditure and altered RQ. Glucose tolerance and insulin sensitivity were impaired in HFD-groups and TAU attenuated these effects. H2 O2 content was increased in CHT and RHT despite no differences in antioxidant enzymes and GSH concentration. AKT and PTEN phosphorylation were significantly increased in CHT but not in RHT. CONCLUSION Our data provide evidence for an association between TAU-induced improved glycaemic control because of PTEN inactivation and higher AKT phosphorylation. These effects seem to be related with altered hepatic redox balance in obese mice, and this effect is impaired by protein malnutrition.
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Affiliation(s)
- Ana P Cappelli
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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22
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Ozaki Y, Takeda T, Akanishi N, Hakuno F, Toyoshima Y, Takahashi SI, Takenaka A. Insulin injection restored increased insulin receptor substrate (IRS)-2 protein during short-term protein restriction but did not affect reduced insulin-like growth factor (IGF)-I mRNA or increased triglyceride accumulation in the liver of rats. Biosci Biotechnol Biochem 2014; 78:130-8. [DOI: 10.1080/09168451.2014.877825] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
Dietary protein restriction reduces insulin-like growth factor (IGF)-I synthesis and impairs growth. Moreover, insulin secretion is impaired and hepatic insulin signaling is activated presumably through upregulation of insulin receptor substrate (IRS)-2, which can stimulate lipogenesis thereby resulting in steatosis. In order to determine whether impaired insulin secretion is the primary cause of these changes, we injected insulin into protein-restricted rats and compensated for the reduction in insulin secretion for 1 and 7 d. Insulin infusion did not overcome the reduction in liver IGF-I mRNA nor the hepatic triglyceride accumulation. In contrast, it clearly suppressed the upregulation of hepatic IRS-2 on day 1, but not on day 7. Furthermore, insulin elimination increased IRS-2 in H4IIE-C3 cells. In summary, we found that reduced insulin secretion during protein restriction directly increased hepatic IRS-2 as a rapid response on day 1, while additional mechanisms contributed to the upregulation of IRS-2 on day 7.
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Affiliation(s)
- Yori Ozaki
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Japan
| | - Tomoya Takeda
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Japan
| | - Narumi Akanishi
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Fumihiko Hakuno
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuka Toyoshima
- Department of Bioregulation, Nippon Medical School, Kawasaki, Japan
| | - Shin-Ichiro Takahashi
- Department of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Asako Takenaka
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Japan
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23
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Rafacho A, Gonçalves-Neto LM, Ferreira FBD, Protzek AOP, Boschero AC, Nunes EA, Zoccal DB. Glucose homoeostasis in rats exposed to acute intermittent hypoxia. Acta Physiol (Oxf) 2013; 209:77-89. [PMID: 23692825 DOI: 10.1111/apha.12118] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 01/15/2013] [Accepted: 05/15/2013] [Indexed: 11/29/2022]
Abstract
AIM Chronic exposure to intermittent hypoxia commonly induces the activation of sympathetic tonus and the disruption of glucose homoeostasis. However, the effects of exposure to acute intermittent hypoxia (AIH) on glucose homoeostasis are not yet fully elucidated. Herein, we evaluated parameters related to glucose metabolism in rats exposed to AIH. METHODS Male adult rats were submitted to 10 episodes of hypoxia (6% O2 , for 45 s) interspersed with 5-min intervals of normoxia (21%), while the control (CTL) group was kept in normoxia. RESULTS Acute intermittent hypoxia rats presented higher fasting glycaemia, normal insulinaemia, increased lactataemia and similar serum lipid levels, compared to controls (n = 10, P < 0.05). Additionally, AIH rats exhibited increased glucose tolerance (GT) (n = 10, P < 0.05) and augmented insulin sensitivity (IS) (n = 10, P < 0.05). The p-Akt/Akt protein ratio was increased in the muscle, but not in the liver and adipose tissue of AIH rats (n = 6, P < 0.05). The elevated glycaemia in AIH rats was associated with a reduction in the hepatic glycogen content (n = 10, P < 0.05). Moreover, the AIH-induced increase in blood glucose concentration, as well as reduced hepatic glycogen content, was prevented by prior systemic administration of the β-adrenergic antagonist (P < 0.05). The effects of AIH on glycaemia and Akt phosphorylation were transient and not observed after 60 min. CONCLUSIONS We suggest that AIH induces an increase in blood glucose concentration as a result of hepatic glycogenolysis recruitment through sympathetic activation. The augmentation of GT and IS might be attributed, at least in part, to increased β-adrenergic sympathetic stimulation and Akt protein activation in skeletal muscles, leading to a higher glucose availability and utilization.
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Affiliation(s)
- A. Rafacho
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - L. M. Gonçalves-Neto
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - F. B. D. Ferreira
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - A. O. P. Protzek
- Department of Structural and Functional Biology; Institute of Biology; UNICAMP - State University of Campinas; Campinas; São Paulo; Brazil
| | - A. C. Boschero
- Department of Structural and Functional Biology; Institute of Biology; UNICAMP - State University of Campinas; Campinas; São Paulo; Brazil
| | - E. A. Nunes
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
| | - D. B. Zoccal
- Department of Physiological Sciences; Centre of Biological Sciences; UFSC - Federal University of de Santa Catarina; Florianópolis; Santa Catarina; Brazil
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Moon HS, Dalamaga M, Kim SY, Polyzos SA, Hamnvik OP, Magkos F, Paruthi J, Mantzoros CS. Leptin's role in lipodystrophic and nonlipodystrophic insulin-resistant and diabetic individuals. Endocr Rev 2013; 34:377-412. [PMID: 23475416 PMCID: PMC3660716 DOI: 10.1210/er.2012-1053] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Leptin is an adipocyte-secreted hormone that has been proposed to regulate energy homeostasis as well as metabolic, reproductive, neuroendocrine, and immune functions. In the context of open-label uncontrolled studies, leptin administration has demonstrated insulin-sensitizing effects in patients with congenital lipodystrophy associated with relative leptin deficiency. Leptin administration has also been shown to decrease central fat mass and improve insulin sensitivity and fasting insulin and glucose levels in HIV-infected patients with highly active antiretroviral therapy (HAART)-induced lipodystrophy, insulin resistance, and leptin deficiency. On the contrary, the effects of leptin treatment in leptin-replete or hyperleptinemic obese individuals with glucose intolerance and diabetes mellitus have been minimal or null, presumably due to leptin tolerance or resistance that impairs leptin action. Similarly, experimental evidence suggests a null or a possibly adverse role of leptin treatment in nonlipodystrophic patients with nonalcoholic fatty liver disease. In this review, we present a description of leptin biology and signaling; we summarize leptin's contribution to glucose metabolism in animals and humans in vitro, ex vivo, and in vivo; and we provide insights into the emerging clinical applications and therapeutic uses of leptin in humans with lipodystrophy and/or diabetes.
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Affiliation(s)
- Hyun-Seuk Moon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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25
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Li X, Wang X, Liu R, Ma Y, Guo H, Hao L, Yao P, Liu L, Sun X, He K, Cao W, Yang X. Chronic leucine supplementation increases body weight and insulin sensitivity in rats on high-fat diet likely by promoting insulin signaling in insulin-target tissues. Mol Nutr Food Res 2013; 57:1067-79. [DOI: 10.1002/mnfr.201200311] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 12/02/2012] [Accepted: 12/29/2012] [Indexed: 01/08/2023]
Affiliation(s)
- Xiang Li
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Xiaolei Wang
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | | | - Yan Ma
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Huailan Guo
- Department of Preventive Medicine; Hubei University of Medicine; Shiyan; Hubei; P. R. China
| | - Liping Hao
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Ping Yao
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Liegang Liu
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Xiufa Sun
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
| | - Ka He
- Department of Nutrition; Gillings School of Global Public Health and School of Medicine, The University of North Carolina at Chapel Hill; Chapel Hill; NC; USA
| | - Wenhong Cao
- Department of Nutrition; Gillings School of Global Public Health and School of Medicine, The University of North Carolina at Chapel Hill; Chapel Hill; NC; USA
| | - Xuefeng Yang
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology; Wuhan; Hubei; P. R. China
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26
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Yang X, Mei S, Wang X, Li X, Liu R, Ma Y, Hao L, Yao P, Liu L, Sun X, Gu H, Liu Z, Cao W. Leucine facilitates insulin signaling through a Gαi protein-dependent signaling pathway in hepatocytes. J Biol Chem 2013; 288:9313-20. [PMID: 23404499 DOI: 10.1074/jbc.m112.409409] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this study, we addressed the direct effect of leucine on insulin signaling. In investigating the associated mechanisms, we found that leucine itself does not activate the classical Akt- or ERK1/2 MAP kinase-dependent signaling pathways but can facilitate the insulin-induced phosphorylations of Akt(473) and ERK1/2 in a time- and dose-dependent manner in cultured hepatocytes. The leucine-facilitated insulin-induced phosphorylation of Akt at residue 473 was not affected by knocking down the key component of mTORC1 or -2 complexes but was blocked by inhibition of c-Src (PP2), PI3K (LY294002), Gαi protein (pertussis toxin or siRNA against Gαi1 gene, or β-arrestin 2 (siRNA)). Similarly, the leucine-facilitated insulin activation of ERK1/2 was also blunted by pertussis toxin. We further show that leucine facilitated the insulin-mediated suppression of glucose production and expression of key gluconeogenic genes in a Gαi1 protein-dependent manner in cultured primary hepatocytes. Together, these results show that leucine can directly facilitate insulin signaling through a Gαi protein-dependent intracellular signaling pathway. This is the first evidence showing that macronutrients like amino acid leucine can facilitate insulin signaling through G proteins directly.
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Affiliation(s)
- Xuefeng Yang
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.
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27
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Taurine Supplementation Restores Insulin Secretion and Reduces ER Stress Markers in Protein-Malnourished Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 776:129-39. [DOI: 10.1007/978-1-4614-6093-0_14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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28
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da Silva PMR, Batista TM, Ribeiro RA, Zoppi CC, Boschero AC, Carneiro EM. Decreased insulin secretion in islets from protein malnourished rats is associated with impaired glutamate dehydrogenase function: effect of leucine supplementation. Metabolism 2012; 61:721-32. [PMID: 22078937 DOI: 10.1016/j.metabol.2011.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 08/27/2011] [Accepted: 09/27/2011] [Indexed: 02/06/2023]
Abstract
We herein studied the role of glutamate dehydrogenase (GDH), in response to leucine (LEU) supplementation, upon insulin secretion of malnourished rats. Weaned male Wistar rats were fed normal-protein (17%) or low-protein diet (6%, LP) for 8 weeks. Half of the rats of each group were supplemented with LEU (1.5%) in the drinking water for the following 4 weeks. Gene and protein expressions, static insulin secretion, and cytoplasmic Ca(2+) oscillations were measured. Glutamate dehydrogenase messenger RNA was 58% lower in LP islets, and LEU supplementation augmented it in 28%. The LP islets secreted less insulin when exposed to 20 mmol/L LEU, 20 mmol/L LEU + 2 mmol/L glutamine (with or without 5 mmol/L aminooxyacetic acid, a branched chain aminotransferase inhibitor, or 20 μmol/L epigallocatechin gallate, a GDH inhibitor), 20 mmol/L α-ketoisocaproate, glutamine + 20 mmol/L β-2-aminobicyclo[2.2.1]heptane-2-carboxylic acid (a GDH activator), and 22.2 mmol/L glucose. Leucine supplementation augmented insulin secretion to levels found in normal-protein islets in all the above conditions, an effect that was blunted when islets were incubated with epigallocatechin gallate. The glutamine + β-2-aminobicyclo[2.2.1]heptane-2-carboxylic acid-induced increased [Ca(2+)](i) and oscillations were higher than those for LP islets. Leucine supplementation normalized these parameters in LP islets. Impaired GDH function was associated with lower insulin release in LP islets, and LEU supplementation normalized insulin secretion via restoration of GDH function. In addition, GDH may contribute to insulin secretion through ameliorations of Ca(2+) handling in LP islets.
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Affiliation(s)
- Priscilla Muniz Ribeiro da Silva
- Department of Anatomy, Cellular Biology and Physiology and Biophysics, Institute of Biology, University of Campinas,PO Box 6109, CEP 13083-970 Campinas, SP, Brazil
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29
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Nicastro H, Zanchi NE, da Luz CR, de Moraes WM, Ramona P, de Siqueira Filho MA, Chaves DF, Medeiros A, Brum PC, Dardevet D, Lancha AH. Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats. Nutrition 2012; 28:465-71. [DOI: 10.1016/j.nut.2011.08.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 06/23/2011] [Accepted: 08/17/2011] [Indexed: 10/15/2022]
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30
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Batista TM, Ribeiro RA, Amaral AG, de Oliveira CA, Boschero AC, Carneiro EM. Taurine supplementation restores glucose and carbachol-induced insulin secretion in islets from low-protein diet rats: involvement of Ach-M3R, Synt 1 and SNAP-25 proteins. J Nutr Biochem 2012; 23:306-12. [DOI: 10.1016/j.jnutbio.2010.12.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 11/21/2010] [Accepted: 12/13/2010] [Indexed: 10/18/2022]
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31
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Leucine nutrition in animals and humans: mTOR signaling and beyond. Amino Acids 2011; 41:1185-93. [DOI: 10.1007/s00726-011-0983-2] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Accepted: 06/15/2011] [Indexed: 12/14/2022]
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32
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Laviano A, Aghilone F, Colagiovanni D, Fiandra F, Giambarresi R, Tordiglione P, Molfino A, Muscaritoli M, Rosa G, Rossi Fanelli F. Metabolic and clinical effects of the supplementation of a functional mixture of amino acids in cerebral hemorrhage. Neurocrit Care 2011; 14:44-9. [PMID: 20972646 DOI: 10.1007/s12028-010-9461-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Oral supplementation of a specific mixture of essential and non-essential amino acids has been shown to modulate hypercatabolism in patients with chronic heart failure, leading to improved clinical outcome. The aim of this study was to test whether such effects could be replicated in an acute clinical model of hypercatabolism. METHODS After approval by the Ethics Committee, patients with acute brain hemorrhage admitted to the Neurosurgical ICU were randomly assigned to receive enterally for 14 days 20% of their estimated nitrogen requirements as a standard protein supplement (control group; n = 9) or as a functional amino acid mixture (Aminotrofic®, Errekappa Euroterapici; study group; n = 10). Metabolic and clinical outcome measures were monitored. RESULTS In the study group, insulin sensitivity and total lymphocyte count appeared to improve when compared with control patients. Less positive blood cultures were found in the study group against control patients (4 vs. 7, respectively; P = 0.05). Also, mortality in the study group was reduced than in control patients (60 vs. 77%; P = n.s.). CONCLUSIONS Supplementation with specific amino acids in critically ill patients may modulate metabolic response and improve clinical outcome.
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33
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Li J, Liu J, Song J, Wang X, Weiss HL, Townsend CM, Gao T, Evers BM. mTORC1 inhibition increases neurotensin secretion and gene expression through activation of the MEK/ERK/c-Jun pathway in the human endocrine cell line BON. Am J Physiol Cell Physiol 2011; 301:C213-26. [PMID: 21508335 DOI: 10.1152/ajpcell.00067.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The mammalian target of rapamycin (mTOR) signaling exists in two complexes: mTORC1 and mTORC2. Neurotensin (NT), an intestinal hormone secreted by enteroendocrine (N) cells in the small bowel, has important physiological effects in the gastrointestinal tract. The human endocrine cell line BON abundantly expresses the NT gene and synthesizes and secretes NT in a manner analogous to that of N cells. Here, we demonstrate that the inhibition of mTORC1 by rapamycin (mTORC1 inhibitor), torin1 (both mTORC1 and mTORC2 inhibitor) or short hairpin RNA-mediated knockdown of mTOR, regulatory associated protein of mTOR (RAPTOR), and p70 S6 kinase (p70S6K) increased basal NT release via upregulating NT gene expression in BON cells. c-Jun activity was increased by rapamycin or torin1 or p70S6K knockdown. c-Jun overexpression dramatically increased NT promoter activity, which was blocked by PD98059, an mitogen-activated protein kinase kinase (MEK) inhibitor. Furthermore, overexpression of MEK1 or extracellular signal-regulated kinase 1 (ERK1) increased c-Jun expression and NT promoter activity. More importantly, PD98059 blocked rapamycin- or torin1-enhanced NT secretion. Consistently, rapamycin and torin1 also increased NT gene expression in Hep3B cells, a human hepatoma cell line that, similar to BON, expresses high levels of NT. Phosphorylation of c-Jun and ERK1/2 was also increased by rapamycin and torin1 in Hep3B cells. Finally, we showed activation of mTOR in BON cells treated with amino acids, high glucose, or serum and, concurrently, the attenuation of ERK1/2 and c-Jun phosphorylation and NT secretion. Together, mTORC1, as a nutrient sensor, negatively regulates NT secretion via the MEK/ERK/c-Jun signaling pathway. Our results identify a physiological link between mTORC1 and MEK/ERK signaling in controlling intestinal hormone gene expression and secretion.
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Affiliation(s)
- Jing Li
- Department of Surgery, University of Kentucky, Lexington, Kentucky 40536, USA
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de Oliveira CAM, Latorraca MQ, de Mello MAR, Carneiro EM. Mechanisms of insulin secretion in malnutrition: modulation by amino acids in rodent models. Amino Acids 2010; 40:1027-34. [DOI: 10.1007/s00726-010-0716-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 07/26/2010] [Indexed: 11/27/2022]
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Soriano S, Gonzalez A, Marroquí L, Tudurí E, Vieira E, Amaral AG, Batista TM, Rafacho A, Boschero AC, Nadal A, Carneiro EM, Quesada I. Reduced insulin secretion in protein malnourished mice is associated with multiple changes in the beta-cell stimulus-secretion coupling. Endocrinology 2010; 151:3543-54. [PMID: 20555033 DOI: 10.1210/en.2010-0008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mechanism by which protein malnutrition impairs glucose-stimulated insulin secretion in the pancreatic beta-cell is not completely known but may be related to alterations in the signaling events involved in insulin release. Here, we aimed to study the stimulus-secretion coupling of beta-cells from mice fed with low-protein (LP) diet or normal-protein (NP) diet for 8 wk after weaning. Patch-clamp measurements in isolated cells showed that beta-cells from LP mice had a resting membrane potential that was more hyperpolarized than controls. Additionally, depolarization and generation of action potentials in response to stimulatory glucose concentrations were also impaired in beta-cells of LP mice. All these alterations in the LP group were most likely attributed to higher ATP-dependent K(+) (K(ATP)) channel activity in resting conditions and lower efficiency of glucose to induce the closure of these channels. Moreover, a Western blot analysis revealed higher protein levels of the sulphonylurea receptor of the K(ATP) channel in islets of LP mice. Because beta-cell Ca(2+) signals depend on electrical activity, intracellular Ca(2+) oscillations were measured by fluorescence microscopy in intact islets, indicating a lower response to glucose in the LP group. Finally, cell-to-cell synchrony of Ca(2+) signals was analyzed by confocal microscopy. Islets from LP mice exhibited a decreased level of coupling among beta-cells, which was probably due to the low expression levels of connexin 36. Therefore, low-protein diet leads to several alterations in the stimulus-secretion coupling of pancreatic beta-cells that might explain the diminished insulin secretion in response to glucose in this malnutrition state.
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Affiliation(s)
- Sergi Soriano
- Instituto de Bioingeniería and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Universidad Miguel Hernández, 03202 Elche, Spain.
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36
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Nicastro H, Artioli GG, Costa ADS, Solis MY, da Luz CR, Blachier F, Lancha AH. An overview of the therapeutic effects of leucine supplementation on skeletal muscle under atrophic conditions. Amino Acids 2010; 40:287-300. [PMID: 20514547 DOI: 10.1007/s00726-010-0636-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Accepted: 05/17/2010] [Indexed: 12/11/2022]
Abstract
The characterization of the mechanisms underlying skeletal muscle atrophy under different conditions has been a constant focus of research. Among anti-atrophic therapies, amino acid supplementation, particularly with leucine, has received a lot of attention. Supplementation has been shown to have remarkable effects on muscle remodeling through protein turnover modulation. This may then impact physiological parameters related to muscle function, and even quality of life. In light of this, leucine supplementation could be a useful therapy for mitigating the atrophic effects of catabolic conditions. The purpose of this review is to present the major results of human studies evaluating the effects of leucine supplementation on structure and function of skeletal muscle in atrophic conditions such as muscle disuse, sarcopenia, and cancer.
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Affiliation(s)
- Humberto Nicastro
- Laboratory of Applied Nutrition and Metabolism, School of Physical Education and Sports, University of São Paulo, São Paulo, Brazil.
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