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Gonzalez-Alcocer A, Gopar-Cuevas Y, Soto-Dominguez A, Loera-Arias MDJ, Saucedo-Cardenas O, Montes de Oca-Luna R, Rodriguez-Rocha H, Garcia-Garcia A. Peripheral tissular analysis of rapamycin's effect as a neuroprotective agent in vivo. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2022; 395:1239-1255. [PMID: 35895156 DOI: 10.1007/s00210-022-02276-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/15/2022] [Indexed: 10/16/2022]
Abstract
Rapamycin is the best-characterized autophagy inducer, which is related to its antiaging and neuroprotective effects. Although rapamycin is an FDA-approved drug for human use in organ transplantation and cancer therapy, its administration as an antiaging and neuroprotective agent is still controversial because of its immunosuppressive and reported side effects. Therefore, it is critical to determine whether the dose that exerts a neuroprotective effect, 35 times lower than that used as an immunosuppressant agent, harms peripheral organs. We validated the rapamycin neuroprotective dosage in a Parkinson's disease (PD) model induced with paraquat. C57BL/6 J mice were treated with intraperitoneal (IP) rapamycin (1 mg/kg) three times per week, followed by paraquat (10 mg/kg) twice per week for 6 weeks, along with rapamycin on alternate days. Rapamycin significantly decreased dopaminergic neuronal loss induced by paraquat. Since rapamycin's neuroprotective effect in a PD model was observed at 7 weeks of treatment; we evaluated its effect on the liver, kidney, pancreas, and spleen. In addition, we prolonged treatment with rapamycin for 14 weeks. Tissue sections were subjected to histochemical, immunodetection, and morphometric analysis. Chronic rapamycin administration does not affect bodyweight, survival, and liver or kidney morphology. Although the pancreas tissular architecture and cellular distribution in Langerhans islets are modified, they may be reversible. The spleen B lymphocyte and macrophage populations were decreased. Notably, the lymphocyte T population was not affected. Therefore, chronic administration of a rapamycin neuroprotective dose does not produce significant tissular alterations. Our findings support the therapeutic potential of rapamycin as a neuroprotective agent.
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Affiliation(s)
- Alfredo Gonzalez-Alcocer
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Yareth Gopar-Cuevas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Adolfo Soto-Dominguez
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Maria de Jesus Loera-Arias
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Odila Saucedo-Cardenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Roberto Montes de Oca-Luna
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Humberto Rodriguez-Rocha
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México
| | - Aracely Garcia-Garcia
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Francisco I. Madero S/N, 64460, Monterrey, Nuevo León, México.
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Wan T, Wang Y, Wang C, Wang H, Li X, Li Y. Overexpression of TRIM32 promotes pancreatic β-cell autophagic cell death through Akt/mTOR pathway under high glucose conditions. Cell Biol Int 2022; 46:2095-2106. [PMID: 36040726 DOI: 10.1002/cbin.11897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 07/25/2022] [Accepted: 08/10/2022] [Indexed: 11/09/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a growing worldwide epidemic and is characterized by progressive pancreatic β-cell dysfunction and insulin resistance. Tripartite motif protein 32 (TRIM32) belongs to the TRIM family protein and has been shown to be involve in insulin resistance in skeletal muscle and the liver. However, the effect of TRIM32 on pancreatic β-cell dysfunction and its mechanism remains unknown. In the current study, we found that serum TRIM32 concentrations of T2DM in patients were significantly elevated compared to those in healthy controls, which indicated that TRIM32 might be used as a diagnostic biomarker in T2DM patients. In INS-1 cells, exposure to high glucose (HG) conditions caused a significant elevation in TRIM32 expression and TRIM32 was located in the nucleus. Overexpression of TRIM32 in INS-1 cells exacerbated the effects of HG-induced autophagy and impaired insulin secretion. In contrast, the silencing of TRIM32 produced the opposite effect. Furthermore, TRIM32 overexpression decreased the phosphorylation levels of Akt and mTOR under HG conditions. However, the activation of Akt/mTOR by MHY1485 reversed the effects of TRIM32 on HG-treated INS-1 cells. Collectively, the present results suggested that TRIM32 participates in the development of T2DM by modulating autophagic cell death and insulin secretion, which might occur through the Akt/mTOR pathway. Thus, TRIM32 might be a promising target in T2DM therapy.
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Affiliation(s)
- Tingting Wan
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.,The Key Laboratory of Myocardial Ischemia, Ministry of Education, Harbin, Heilongjiang, China
| | - Yidan Wang
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.,The Key Laboratory of Myocardial Ischemia, Ministry of Education, Harbin, Heilongjiang, China
| | - Chunxu Wang
- The Key Laboratory of Myocardial Ischemia, Ministry of Education, Harbin, Heilongjiang, China.,Department of Hematology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Hongjie Wang
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiudan Li
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.,The Key Laboratory of Myocardial Ischemia, Ministry of Education, Harbin, Heilongjiang, China
| | - Yanbo Li
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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Sherafati-Moghadam M, Pahlavani HA, Daryanoosh F, Salesi M. The effect of high-intensity interval training (HIIT) on protein expression in Flexor Hallucis Longus (FHL) and soleus (SOL) in rats with type 2 diabetes. J Diabetes Metab Disord 2022. [PMID: 36404870 PMCID: PMC9672293 DOI: 10.1007/s40200-022-01091-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose In people with diabetes, one of the problems for patients is muscle wasting and inhibition of the protein synthesis pathway. This study aimed to evaluate the effects of HIIT on protein expression in two skeletal muscles, flexor hallucis longus (FHL) and soleus (SOL) in rats with type 2 diabetes mellitus (T2DM). Materials and methods Diabetes initially was induced by streptozotocin (STZ) and nicotinamide. Rats with type 2 diabetes were randomly and equally divided into control (n = 6) and HIIT groups (n = 6). After 8 weeks of training, the content of total and phosphorylated proteins of serine/threonine-protein kinases (AKT1), mammalian target of rapamycin (mTOR), P70 ribosomal protein S6 kinase 1 (P70S6K1), and 4E (eIF4E)-binding protein 1 (4E-BP1) in FHL and SOL muscles were measured by Western blotting. While body weight and blood glucose were also controlled. Results In the HIIT training group, compared to the control group, a significant increase in the content of AKT1 (0.003) and mTOR (0.001) proteins was observed in the FHL muscle. Also, after 8 weeks of HIIT training, protein 4E-BP1 (0.001) was increased in SOL muscle. However, there was no significant change in other proteins in FHL and SOL muscle. Conclusions In rats with type 2 diabetes appear to HIIT leading to more protein expression of fast-twitch muscles than slow-twitch muscles. thus likely HIIT exercises can be an important approach to increase protein synthesis and prevent muscle atrophy in people with type 2 diabetes.
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Soni R, Shah J. Deciphering Intertwined Molecular Pathways Underlying Metabolic Syndrome Leading to Parkinson's Disease. ACS Chem Neurosci 2022; 13:2240-2251. [PMID: 35856649 DOI: 10.1021/acschemneuro.2c00165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that gradually develops over time in a progressive manner. The main culprit behind the disease pathology is dopaminergic deficiency in Substantia nigra Pars Compacta (SNpc) due to neuronal degeneration. However, there are other factors that are not only associated with it but also somehow responsible for inception of pathology. Metabolic syndrome is one such risk factor for PD. Metabolic syndrome is a cluster of diseases mainly including diabetes, hypertension, obesity, and hyperlipidemia which pose a risk for developing cardiovascular disorders. All of these disorders have their own pathological pathways that intertwine with PD pathology. This leads to alpha-synuclein aggregation, neuroinflammation, mitochondrial dysfunction, and oxidative stress which are facets in initiating PD pathology. Although few reports are available, this area is underexplored and has contradictory views. Hence, further studies are needed in order to establish a definite relationship between PD and metabolic syndrome. In this review, we aim to elucidate the molecular mechanisms to confirm the association between them and pave the way for potential repurposing of therapies.
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Affiliation(s)
- Ritu Soni
- Department of Pharmacology, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
| | - Jigna Shah
- Department of Pharmacology, Institute of Pharmacy, Nirma University, Ahmedabad, Gujarat 382481, India
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Rashidmayvan M, Sahebi R, Ghayour-Mobarhan M. Long non-coding RNAs: a valuable biomarker for metabolic syndrome. Mol Genet Genomics 2022; 297:1169-1183. [PMID: 35854006 DOI: 10.1007/s00438-022-01922-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/25/2022] [Indexed: 10/17/2022]
Abstract
Long non-coding RNAs (lncRNAs) have become important regulators of gene expression because they affect a wide range of biological processes, such as cell growth, death, differentiation, and aging. More and more evidence suggests that lncRNAs play a role in maintaining metabolic homeostasis. When certain lncRNAs are out of balance, metabolic disorders like diabetes, obesity, and heart disease get worse. In this review, we talk about what we know about how lncRNAs control metabolism, with a focus on diseases caused by long-term inflammation and the characteristics of the metabolic syndrome. We looked at lncRNAs and their molecular targets in the pathogenesis of signaling pathways. We also talked about how lncRNAs are becoming more and more interesting as diagnostic and therapeutic targets for improving metabolic homeostasis.
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Affiliation(s)
- Mohammad Rashidmayvan
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reza Sahebi
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Majid Ghayour-Mobarhan
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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RyR2/IRBIT regulates insulin gene transcript, insulin content, and secretion in the insulinoma cell line INS-1. Sci Rep 2022; 12:7713. [PMID: 35562179 PMCID: PMC9095623 DOI: 10.1038/s41598-022-11276-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/31/2022] [Indexed: 12/01/2022] Open
Abstract
The role of ER Ca2+ release via ryanodine receptors (RyR) in pancreatic β-cell function is not well defined. Deletion of RyR2 from the rat insulinoma INS-1 (RyR2KO) enhanced IP3 receptor activity stimulated by 7.5 mM glucose, coincident with reduced levels of the protein IP3Receptor Binding protein released with Inositol 1,4,5 Trisphosphate (IRBIT). Insulin content, basal (2.5 mM glucose) and 7.5 mM glucose-stimulated insulin secretion were reduced in RyR2KO and IRBITKO cells compared to controls. INS2 mRNA levels were reduced in both RyR2KO and IRBITKO cells, but INS1 mRNA levels were specifically decreased in RyR2KO cells. Nuclear localization of S-adenosylhomocysteinase (AHCY) was increased in RyR2KO and IRBITKO cells. DNA methylation of the INS1 and INS2 gene promotor regions was very low, and not different among RyR2KO, IRBITKO, and controls, but exon 2 of the INS1 and INS2 genes was more extensively methylated in RyR2KO and IRBITKO cells. Exploratory proteomic analysis revealed that deletion of RyR2 or IRBIT resulted in differential regulation of 314 and 137 proteins, respectively, with 41 in common. These results suggest that RyR2 regulates IRBIT levels and activity in INS-1 cells, and together maintain insulin content and secretion, and regulate the proteome, perhaps via DNA methylation.
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Roles of mTOR in the Regulation of Pancreatic β-Cell Mass and Insulin Secretion. Biomolecules 2022; 12:biom12050614. [PMID: 35625542 PMCID: PMC9138643 DOI: 10.3390/biom12050614] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 12/07/2022] Open
Abstract
Pancreatic β-cells are the only type of cells that can control glycemic levels via insulin secretion. Thus, to explore the mechanisms underlying pancreatic β-cell failure, many reports have clarified the roles of important molecules, such as the mechanistic target of rapamycin (mTOR), which is a central regulator of metabolic and nutrient cues. Studies have uncovered the roles of mTOR in the function of β-cells and the progression of diabetes, and they suggest that mTOR has both positive and negative effects on pancreatic β-cells in the development of diabetes.
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Wang X, Zhang Y, Zheng W, Wang J, Wang Y, Song W, Liang S, Guo C, Ma X, Li G. Dynamic changes and early predictive value of branched-chain amino acids in gestational diabetes mellitus during pregnancy. Front Endocrinol (Lausanne) 2022; 13:1000296. [PMID: 36313758 PMCID: PMC9614652 DOI: 10.3389/fendo.2022.1000296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Branched-chain amino acids (BCAAs) are closely associated with type 2 diabetes mellitus, but their roles in gestational diabetes mellitus (GDM) are still controversial. This study aims to explore the dynamic changes of BCAAs during pregnancy and identify potential early biomarkers for GDM. METHODS This study is a nested case-control study involved 49 women with GDM and 50 age- and body mass index (BMI)-matched healthy pregnant women. The dynamic changes of valine (Val), isoleucine (Ile), and leucine (Leu) were detected in the first (8-12 weeks) and second trimesters (24-28 weeks) by liquid chromatography-mass spectrometry. RESULTS Serum Val, Ile, and Leu were higher in GDM patients than in controls in the first trimester. Compared with the first trimester, the serum Val, Ile, and Leu in GDM patients were decreased in the second trimester. In addition, Val, Ile, and Leu in the first trimester were the risk factors for GDM, and Ile presented a high predictive value for GDM. Ile + age (≥ 35) + BMI (≥ 24) exhibited the highest predictive value for GDM (AUC = 0.902, sensitivity = 93.9%, specificity = 80%). CONCLUSION Maternal serum Ile in the first trimester was a valuable biomarker for GDM. Ile combined with advanced maternal age and overweight may be used for the early prediction of GDM.
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Affiliation(s)
- Xiaoxin Wang
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Ya Zhang
- Department of Genetics, National Research Institute for Family Planning, Beijing, China
- Environmental and Spatial Epidemiology Research Center, National Human Genetic Resources Center, Beijing, China
| | - Wei Zheng
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Jia Wang
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Yuanyuan Wang
- Department of Genetics, National Research Institute for Family Planning, Beijing, China
- Environmental and Spatial Epidemiology Research Center, National Human Genetic Resources Center, Beijing, China
| | - Wei Song
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Shengnan Liang
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Cuimei Guo
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Xu Ma
- Department of Genetics, National Research Institute for Family Planning, Beijing, China
- Environmental and Spatial Epidemiology Research Center, National Human Genetic Resources Center, Beijing, China
- *Correspondence: Xu Ma, ; Guanghui Li,
| | - Guanghui Li
- Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
- *Correspondence: Xu Ma, ; Guanghui Li,
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Insulin Signal Transduction Perturbations in Insulin Resistance. Int J Mol Sci 2021; 22:ijms22168590. [PMID: 34445300 PMCID: PMC8395322 DOI: 10.3390/ijms22168590] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/23/2021] [Accepted: 07/28/2021] [Indexed: 12/11/2022] Open
Abstract
Type 2 diabetes mellitus is a widespread medical condition, characterized by high blood glucose and inadequate insulin action, which leads to insulin resistance. Insulin resistance in insulin-responsive tissues precedes the onset of pancreatic β-cell dysfunction. Multiple molecular and pathophysiological mechanisms are involved in insulin resistance. Insulin resistance is a consequence of a complex combination of metabolic disorders, lipotoxicity, glucotoxicity, and inflammation. There is ample evidence linking different mechanistic approaches as the cause of insulin resistance, but no central mechanism is yet described as an underlying reason behind this condition. This review combines and interlinks the defects in the insulin signal transduction pathway of the insulin resistance state with special emphasis on the AGE-RAGE-NF-κB axis. Here, we describe important factors that play a crucial role in the pathogenesis of insulin resistance to provide directionality for the events. The interplay of inflammation and oxidative stress that leads to β-cell decline through the IAPP-RAGE induced β-cell toxicity is also addressed. Overall, by generating a comprehensive overview of the plethora of mechanisms involved in insulin resistance, we focus on the establishment of unifying mechanisms to provide new insights for the future interventions of type 2 diabetes mellitus.
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Ding C, Egli L, Bosco N, Sun L, Goh HJ, Yeo KK, Yap JJL, Actis-Goretta L, Leow MKS, Magkos F. Plasma Branched-Chain Amino Acids Are Associated With Greater Fasting and Postprandial Insulin Secretion in Non-diabetic Chinese Adults. Front Nutr 2021; 8:664939. [PMID: 33996878 PMCID: PMC8113402 DOI: 10.3389/fnut.2021.664939] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 03/30/2021] [Indexed: 12/22/2022] Open
Abstract
Background: Plasma branched-chain amino acids (BCAA) are consistently elevated in subjects with obesity and type 2 diabetes (T2DM) and correlate with insulin resistance. The association of BCAA with insulin secretion and clearance rates has not been adequately described. Objective: To evaluate the relationships between fasting and postprandial plasma BCAA, insulin secretion and insulin clearance. Design: Ninety-five non-diabetic Chinese subjects (43 females) underwent a mixed-meal tolerance test; blood biomarkers including BCAAs (leucine, isoleucine, valine) were measured for 6 h. Fasting and postprandial insulin secretion rates (ISR) and insulin clearance were determined by oral minimal modeling of glucose and C-peptide. Results: Fasting and postprandial plasma BCAA correlated strongly with each other (ρ = 0.796, P < 0.001), and both were positively associated with basal ISR (ρ = 0.45/0.36, P < 0.001), total postprandial ISR AUC (ρ = 0.37/0.45, P < 0.001), and negatively with insulin clearance (ρ = -0.29/-0.29, P < 0.01), after adjusting for sex and body mass index. These relationships largely persisted after adjusting further for insulin resistance and postprandial glucose. Compared with subjects in the middle and lowest tertiles for fasting or postprandial plasma BCAA, subjects in the highest tertile had significantly greater postprandial glucose (by 7-10%) and insulin (by 74-98%) concentrations, basal ISRs (by 34-53%), postprandial ISR AUCs (by 41-49%), and lower insulin clearance rates (by 17-22%) (all P < 0.05). Conclusions: Fasting and postprandial plasma BCAA levels are associated with greater fasting and postprandial insulin secretion and reduced insulin clearance in healthy Chinese subjects. These observations potentially highlight an additional layer of involvement of BCAA in the regulation of glucose homeostasis.
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Affiliation(s)
| | - Leonie Egli
- Nestlé Institute of Health Sciences, Nestlé Research, Lausanne, Switzerland
| | - Nabil Bosco
- Nestlé Research, Singapore, Singapore
- Nestlé Institute of Health Sciences, Nestlé Research, Lausanne, Switzerland
| | - Lijuan Sun
- Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - Hui Jen Goh
- Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - Khung Keong Yeo
- Duke-NUS Medical School, Singapore, Singapore
- National Heart Centre Singapore, Singapore, Singapore
| | - Jonathan Jiunn Liang Yap
- National Heart Centre Singapore, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | | | - Melvin Khee-Shing Leow
- Singapore Institute for Clinical Sciences, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore, Singapore
| | - Faidon Magkos
- Department of Nutrition, Exercise & Sports, University of Copenhagen, Frederiksberg, Denmark
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Soliman GA, Schooling CM. Causal association between mTOR-dependent EIF-4E and EIF-4A circulating protein levels and type 2 diabetes: a Mendelian randomization study. Sci Rep 2020; 10:15737. [PMID: 32978410 PMCID: PMC7519073 DOI: 10.1038/s41598-020-71987-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
The mammalian Target of Rapamycin complex 1 (mTORC1) nutrient-sensing pathway is a central regulator of cell growth and metabolism and is dysregulated in diabetes. The eukaryotic translation initiation factor 4E (EIF-4E) protein, a key regulator of gene translation and protein function, is controlled by mTORC1 and EIF-4E Binding Proteins (EIF4EBPs). Both EIF4EBPs and ribosomal protein S6K kinase (RP-S6K) are downstream effectors regulated by mTORC1 but converge to regulate two independent pathways. We investigated whether the risk of type 2 diabetes varied with genetically predicted EIF-4E, EIF-4A, EIF-4G, EIF4EBP, and RP-S6K circulating levels using Mendelian Randomization. We estimated the causal role of EIF-4F complex, EIF4EBP, and S6K in the circulation on type 2 diabetes, based on independent single nucleotide polymorphisms strongly associated (p = 5 × 10–6) with EIF-4E (16 SNPs), EIF-4A (11 SNPs), EIF-4G (6 SNPs), EIF4EBP2 (12 SNPs), and RP-S6K (16 SNPs). The exposure data were obtained from the INTERVAL study. We applied these SNPs for each exposure to publically available genetic associations with diabetes from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) case (n = 26,676) and control (n = 132,532) study (mean age 57.4 years). We meta-analyzed SNP-specific Wald-estimates using inverse variance weighting with multiplicative random effects and conducted sensitivity analysis. Mendelian Randomization (MR-Base) R package was used in the analysis. The PhenoScanner curated database was used to identify disease associations with SNP gene variants. EIF-4E is associated with a lowered risk of type 2 diabetes with an odds ratio (OR) 0.94, 95% confidence interval (0.88, 0.99, p = 0.03) with similar estimates from the weighted median and MR-Egger. Similarly, EIF-4A was associated with lower risk of type 2 diabetes with odds ratio (OR) 0.90, 95% confidence interval (0.85, 0.97, p = 0.0003). Sensitivity analysis using MR-Egger and weighed median analysis does not indicate that there is a pleiotropic effect. This unbiased Mendelian Randomization estimate is consistent with a protective causal association of EIF-4E and EIF-4A on type 2 diabetes. EIF-4E and EIF-4A may be targeted for intervention by repurposing existing therapeutics to reduce the risk of type 2 diabetes.
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Affiliation(s)
- Ghada A Soliman
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.
| | - C Mary Schooling
- Department of Environmental, Occupational and Geospatial Health Sciences, The City University of New York, Graduate School of Public Health and Health Policy, 55 West 125th St, New York, NY, 10027, USA.,School of Public Health, Li Ka Shing, Faculty of Medicine, The University of Hong Kong, 7 Sassoon Road, Hong Kong, China
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12
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Fawzy MS, Abdelghany AA, Toraih EA, Mohamed AM. Circulating long noncoding RNAs H19 and GAS5 are associated with type 2 diabetes but not with diabetic retinopathy: A preliminary study. Bosn J Basic Med Sci 2020; 20:365-371. [PMID: 31999937 PMCID: PMC7416173 DOI: 10.17305/bjbms.2019.4533] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 12/14/2019] [Indexed: 12/11/2022] Open
Abstract
Recently, a wide range of biological and pathological roles of long noncoding RNAs (lncRNAs) have been discovered. However, the potential role of circulating lncRNAs H19 and GAS5 in type 2 diabetes mellitus (T2DM) and diabetic retinopathy (DR) is not clear. Here, we assessed the plasma levels of H19 and GAS5 lncRNAs in T2DM patients with/without DR and evaluated if H19 and GAS5 pre-treatment plasma levels are a predictor of early response to a single aflibercept dose in DR subgroup. Plasma lncRNA expression profiles of 119 T2DM patients (66 with DR and 53 without DR) and 110 healthy controls were determined by quantitative reverse transcription PCR. The association of lncRNA expression profiles with clinical features and aflibercept early response in DR patients was investigated. Relative H19 expression levels were significantly increased in T2DM group (including DR and non-DR subgroups) vs. controls, while GAS5 levels were decreased in T2DM group (p < 0.001). There was no significant difference in H19 and GAS5 expression levels between DR and non-DR subgroups. H19 and GAS5 expression profiles were not significantly correlated with clinical parameters or response to aflibercept therapy in DR subgroup. Our findings indicate that the circulating lncRNAs H19 and GAS5 may be associated with T2DM prevalence but may not have an important diagnostic/prognostic role in DR or early response to aflibercept intravitreal injection in DR patients. Large-scale transcriptomic studies are warranted to validate our results and investigate other lncRNA candidates in T2DM.
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Affiliation(s)
- Manal S Fawzy
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; Department of Biochemistry, Faculty of Medicine, Northern Border University, Arar, Saudi Arabia
| | - Ahmed A Abdelghany
- Department of Ophthalmology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Eman A Toraih
- Department of Surgery, School of Medicine, Tulane University, New Orleans, Louisiana, USA; Department of Histology and Cell Biology (Genetics Unit), Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Abeer M Mohamed
- Department of Clinical Pathology and Clinical Chemistry, Faculty of Medicine, Sohag University, Sohag, Egypt; Department of Clinical Laboratory Sciences, Al-Ghad International College for Applied Medical Sciences, Abha, Saudi Arabia
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13
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Saleh AA, Kasem HE, Zahran ES, El-Hefnawy SM. Cell-free long non-coding RNAs (LY86-AS1 & HCG27_201and GAS5) as biomarkers for pre-diabetes and type 2 DM in Egypt. Biochem Biophys Rep 2020; 23:100770. [PMID: 32514472 PMCID: PMC7267222 DOI: 10.1016/j.bbrep.2020.100770] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/14/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022] Open
Abstract
Background Increasing interest has been focused on lncRNAs as potential markers in the pathogenesis and progression of numerous diseases. Aim We aimed to investigate the expression pattern and role of cell-free lncRNAs (GAS5, HCG27_201 and LY86-AS1) in pre-diabetic, diabetic and T2DM groups. Subjects & methods Quantification of the expression level of cell-free lncRNAs (GAS5, HCG27_201 and LY86-AS1) was performed by real-time PCR in 210 individuals classified in diabetic (T2DM), pre-diabetic and control groups. Results Significant differences were observed in the relative expression level of lncRNAs (GAS5, LY86-AS1 and HCG27_201) among the three studied groups. The LncRNA expression levels decreased gradually from the control to the pre-diabetic group and reached the lowest values in the T2DM group. The A receiver operating characteristic curve (ROC) was applied to identify a cut-off value for each of the three genes among our groups. The three lncRNAs showed promising results in discriminating between the diabetic patients and controls, with HCG27_201 gene expression having the best performance. Furthermore, lncRNA expression was able to predict the future development of DM in the pre-diabetics because ROC analysis among diabetics and pre-diabetics revealed considerable results. GAS5 gene expression showed the best performance. Additionally, HCG27_201 expression was the most valuable biomarker for differentiating between pre-diabetics and controls and presented a sensitivity of 91% and specificity of 64%. Conclusions We concluded that cell free lncRNAs (GAS5, LY86-AS1 and HCG27_201) could be considered promising diagnostic and predictive biomarkers for DM and that HCG27_201 could act as a potential diagnostic biomarker for pre-diabetes. lncRNAs are involved in T2DM pathological process. lncRNA showed ability to predict development of DM. GAS5, LY86-AS1 and HCG27_201 could be considered as diagnostic biomarkers for DM. The three studied lncRNA could also be considered as predictive biomarkers for DM. HCG27_201 could act as a potential diagnostic biomarker for pre-diabetes.
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Affiliation(s)
- Amany A Saleh
- Medical Biochemistry & Molecular Biology, Menoufia University, Egypt
| | - Heba E Kasem
- Internal Medicine Departments, Faculty of Medicine, Menoufia University, Egypt
| | - Enas S Zahran
- Internal Medicine Departments, Faculty of Medicine, Menoufia University, Egypt
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Shen L, Gu Y, Qiu Y, Cheng T, Nie A, Cui C, Fu C, Li T, Li X, Fu L, Wang Y, Ni Q, Wang Q, Wang W, Feng B. Atorvastatin Targets the Islet Mevalonate Pathway to Dysregulate mTOR Signaling and Reduce β-Cell Functional Mass. Diabetes 2020; 69:48-59. [PMID: 31649162 DOI: 10.2337/db19-0178] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 10/14/2019] [Indexed: 11/13/2022]
Abstract
Statins are cholesterol-lowering agents that increase the incidence of diabetes and impair glucose tolerance via their detrimental effects on nonhepatic tissues, such as pancreatic islets, but the underlying mechanism has not been determined. In atorvastatin (ator)-treated high-fat diet-fed mice, we found reduced pancreatic β-cell size and β-cell mass, fewer mature insulin granules, and reduced insulin secretion and glucose tolerance. Transcriptome profiling of primary pancreatic islets showed that ator inhibited the expression of pancreatic transcription factor, mechanistic target of rapamycin (mTOR) signaling, and small G protein (sGP) genes. Supplementation of the mevalonate pathway intermediate geranylgeranyl pyrophosphate (GGPP), which is produced by 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, significantly restored the attenuated mTOR activity, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) expression, and β-cell function after ator, lovastatin, rosuvastatin, and fluvastatin treatment; this effect was potentially mediated by sGP prenylation. Rab5a, the sGP in pancreatic islets most affected by ator treatment, was found to positively regulate mTOR signaling and β-cell function. Rab5a knockdown mimicked the effect of ator treatment on β-cells. Thus, ator impairs β-cell function by regulating sGPs, for example, Rab5a, which subsequently attenuates islet mTOR signaling and reduces functional β-cell mass. GGPP supplementation could constitute a new approach for preventing statin-induced hyperglycemia.
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Affiliation(s)
- Linyan Shen
- Department of Metabolism and Endocrinology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yanyun Gu
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yixuan Qiu
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tingting Cheng
- Department of Metabolism and Endocrinology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Aifang Nie
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Canqi Cui
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chenyang Fu
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tingting Li
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuelin Li
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lihong Fu
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanqiu Wang
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qicheng Ni
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qidi Wang
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiqing Wang
- National Research Centre for Endocrine and Metabolic Diseases, Shanghai Institute for Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bo Feng
- Department of Metabolism and Endocrinology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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Hidayat K, Du X, Shi BM. Milk in the prevention and management of type 2 diabetes: The potential role of milk proteins. Diabetes Metab Res Rev 2019; 35:e3187. [PMID: 31111646 DOI: 10.1002/dmrr.3187] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 03/31/2019] [Accepted: 05/07/2019] [Indexed: 12/17/2022]
Abstract
Globally, diabetes mellitus is not only considered a leading cause of mortality and morbidities but has also created a substantial economic burden. There is growing evidence that foods and their components can be implemented in the prevention and management of type 2 diabetes mellitus (T2DM). Increased dairy consumption has been linked to a lower risk of T2DM. The protective role of dairy foods in the development of T2DM is thought to be largely attributable to dairy nutrients, one of them being dairy protein. There is considerable evidence that milk proteins increase the postprandial insulin response and lower the postprandial blood glucose response in both healthy subjects and patients with T2DM. The exact mechanisms by which milk proteins lower postprandial glucose levels are yet to established; however, the amino acids and bioactive peptides derived from milk proteins are thought to modify a physiological milieu, which includes delayed gastric emptying and the enhancement of incretin and insulin responses, consequently leading to lower postprandial glucose levels. The present review will focus on providing a clear presentation of the potential implementation of milk proteins as a dietary supplement in the prevention and management of T2DM by summarizing the relevant supporting evidence for this particular topic.
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Affiliation(s)
- Khemayanto Hidayat
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xuan Du
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Bi-Min Shi
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Soochow University, Suzhou, China
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Mohamadi M, Ghaedi H, Kazerouni F, Erfanian Omidvar M, Kalbasi S, Shanaki M, Miraalamy G, Rahimipour A. Deregulation of long noncoding RNA SNHG17 and TTC28-AS1 is associated with type 2 diabetes mellitus. Scandinavian Journal of Clinical and Laboratory Investigation 2019; 79:519-523. [PMID: 31509021 DOI: 10.1080/00365513.2019.1664760] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Long noncoding RNAs (lncRNAs) have emerged as key players in several biological processes and complex diseases including type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the expression levels of SNHG17 and TTC28-AS1 in T2DM patients. Quantitative real-time RT-PCR analysis was performed using peripheral blood mononuclear cells (PBMCs) samples from patients diagnosed with T2DM and healthy controls. Binary logistic regression analysis was carried out to determine the odds of development of T2DM based on expression levels of lncRNAs and clinical characteristic of the subjects. Spearman's correlation analysis was used to clarify the correlation between SNHG17 and TTC28-AS1 expressions to metabolic features. We found that SNHG17 and TTC28-AS1were down-regulated in the T2DM group compared to the healthy control group. The logistic regression revealed that body mass index (BMI), systolic blood pressure (SBP), fasting blood glucose (FBG) and TTC28-AS1 expression substantially affect T2DM susceptibility. Furthermore, expression of SNHG17 was negatively correlated with high-density lipoprotein cholesterol (HDL-C) and expression of TTC28-AS1 was positively correlated with low-density lipoprotein cholesterol (LDL-C). Decreased expressions of lncRNAs TTC28-AS1 and SNHG17 in T2DM are possibly associated with the development of T2DM.
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Affiliation(s)
- Mahroo Mohamadi
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Hamid Ghaedi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Faranak Kazerouni
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Maryam Erfanian Omidvar
- Department of Clinical Biochemistry, Faculty of Medicine, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Saeid Kalbasi
- Department of Endocrinology, Loghman Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Mehrnoosh Shanaki
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Ghasem Miraalamy
- Ali-Asghar Hospital, Iran University of Medical Sciences , Tehran , Iran
| | - Ali Rahimipour
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences , Tehran , Iran.,Department of Clinical Biochemistry, Faculty of Medicine, Shahid Beheshti University of Medical Sciences , Tehran , Iran
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Marafie SK, Al-Shawaf EM, Abubaker J, Arefanian H. Palmitic acid-induced lipotoxicity promotes a novel interplay between Akt-mTOR, IRS-1, and FFAR1 signaling in pancreatic β-cells. Biol Res 2019; 52:44. [PMID: 31426858 PMCID: PMC6699284 DOI: 10.1186/s40659-019-0253-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/12/2019] [Indexed: 01/05/2023] Open
Abstract
Background Free fatty acid receptor 1 (FFAR1) is G-protein coupled receptor predominantly expressed in pancreatic β-cells that is activated by a variety of free fatty acids (FFAs). Once activated, it promotes glucose-stimulated insulin secretion (GSIS). However, increased levels of FFAs lead to lipotoxicity, inducing loss of β-cell function. FFAR1 plays a key role in the development of type 2 diabetes (T2D), and previous studies have indicated the importance of developing anti-diabetic therapies against FFAR1, although its role in the regulation of β-cell function remains unclear. The present study investigated the role of FFAR1 under lipotoxic conditions using palmitic acid (PA). The rat insulinoma 1 clone 832/13 (INS-1 832/13) cell line was used as a model as it physiologically resembles native pancreatic β-cells. Key players of the insulin signaling pathway, such as mTOR, Akt, IRS-1, and the insulin receptor (INSR1β), were selected as candidates to be analyzed under lipotoxic conditions. Results We revealed that PA-induced lipotoxicity affected GSIS in INS-1 cells and negatively modulated the activity of both IRS-1 and Akt. Reduced phosphorylation of both IRS-1 S636/639 and Akt S473 was observed, in addition to decreased expression of both INSR1β and FFAR1. Moreover, transient knockdown of FFAR1 led to a reduction in IRS-1 mRNA expression and an increase in INSR1β mRNA. Finally, PA affected localization of FFAR1 from the cytoplasm to the perinucleus. Conclusions In conclusion, our study suggests a novel regulatory involvement of FFAR1 in crosstalk with mTOR–Akt and IRS-1 signaling in β-cells under lipotoxic conditions.
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Affiliation(s)
- Sulaiman K Marafie
- Biochemistry & Molecular Biology Department, Dasman Diabetes Institute, P. O. Box 1180, 15462, Dasman, Kuwait.
| | - Eman M Al-Shawaf
- Biochemistry & Molecular Biology Department, Dasman Diabetes Institute, P. O. Box 1180, 15462, Dasman, Kuwait
| | - Jehad Abubaker
- Biochemistry & Molecular Biology Department, Dasman Diabetes Institute, P. O. Box 1180, 15462, Dasman, Kuwait
| | - Hossein Arefanian
- Microbiology & Immunology Department, Dasman Diabetes Institute, P. O. Box 1180, 15462, Dasman, Kuwait.
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Orexin-A Stimulates Insulin Secretion Through the Activation of the OX1 Receptor and Mammalian Target of Rapamycin in Rat Insulinoma Cells. Pancreas 2019; 48:568-573. [PMID: 30946236 DOI: 10.1097/mpa.0000000000001280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The study aimed to investigate the involvement of the mammalian target of rapamycin (mTOR) signaling pathway in orexin-A/OX1 receptor-induced insulin secretion in rat insulinoma INS-1 cells. METHODS Rat insulinoma INS-1 cells were grown and treated with various concentrations of orexin-A, with or without OX1 receptor-selective antagonist SB674042 or the phosphatidylinositol 3-kinase/mTOR antagonist PF-04691502. Insulin release experiments, Western blot analysis, and statistical analysis were conducted using INS-1 cells. RESULTS Our results showed that treating cells with orexin-A increased the expression of the OX1 receptor and the phosphorylation of mTOR in a concentration-dependent manner. An increase in insulin secretion was also observed for cells treated with orexin-A. We further demonstrated that the increase in insulin secretion was dependent on the activation of the OX1 receptor and mTOR signaling pathway by using the OX1 receptor-selective antagonist SB674042 or the phosphatidylinositol 3-kinase/mTOR antagonist PF-04691502, which abolished the effects of orexin-A treatment. CONCLUSIONS Our results concluded that orexin-A/OX1 receptor stimulates insulin secretion by activating AKT and its downstream target, mTOR. Therefore, orexins may regulate the energy balance for cell survival with the involvement of mTOR in this process.
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MicroRNA-125b-5p improves pancreatic β-cell function through inhibiting JNK signaling pathway by targeting DACT1 in mice with type 2 diabetes mellitus. Life Sci 2019; 224:67-75. [PMID: 30684546 DOI: 10.1016/j.lfs.2019.01.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 01/08/2019] [Accepted: 01/18/2019] [Indexed: 11/23/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a progressive disease, accompanied by increased insulin resistance and deteriorating β-cell function. Previous studies have revealed that microRNA (miRNA) plays a crucial role in the treatment of T2DM. Hence, we aim to investigate the role of microRNA-125b-5p (miR-125b-5p) in pancreatic β-cell function and insulin sensitivity of mice with T2DM with the involvement of Dishevelled antagonist Dapper1 (DACT1) and the c-Jun NH2-terminal kinases (JNK) signaling pathway. Firstly, a mouse model of T2DM was established by administering a high-fat diet plus low dosage of streptozotocin, and function of pancreatic β-cell and insulin sensitivity in the normal and T2DM mice were detected. Then, the pancreatic β-cells were collected from pancreatic islet tissues and treated with different mimics, inhibitors and siRNAs. After that, the relationship among miR-125b-5p, DACT1, and the JNK signaling-related factors in T2DM mice was determined. Finally, cell proliferation and apoptosis were determined. Mice with T2DM had lower pancreatic β-cell function and insulin sensitivity, as well as diminished expression of miR-125b-5p but enhanced expressions of DACT1, JNK and c-Jun. miR-125b-5p inhibited DACT1 expression and the activation of the JNK signaling pathway, as well as restrained cell proliferation and promoted cell apoptosis. The current results suggest that up-regulated miR-125b-5p promotes insulin sensitivity and enhances pancreatic β-cell function through inhibiting the JNK signaling pathway by negatively mediating DACT1.
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20
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Tobassum S, Tahir HM, Arshad M, Zahid MT, Ali S, Ahsan MM. Nature and applications of scorpion venom: an overview. TOXIN REV 2018. [DOI: 10.1080/15569543.2018.1530681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Saadia Tobassum
- Department of Zoology, Government College University, Lahore, Pakistan
| | | | - Muhammad Arshad
- Department of Zoology, University of Education Lower Mall Campus, Lahore, Pakistan
| | | | - Shaukat Ali
- Department of Zoology, Government College University, Lahore, Pakistan
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Chu KY, O'Reilly L, Mellet N, Meikle PJ, Bartley C, Biden TJ. Oleate disrupts cAMP signaling, contributing to potent stimulation of pancreatic β-cell autophagy. J Biol Chem 2018; 294:1218-1229. [PMID: 30518550 DOI: 10.1074/jbc.ra118.004833] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is critical for maintaining cellular function via clearance of excess nutrients and damaged organelles. In pancreatic β-cells, it helps counter the endoplasmic reticulum (ER) stress that impairs insulin secretory capacity during Type 2 diabetes. Chronic exposure of β-cells to saturated fatty acids (FAs) such as palmitate stimulates ER stress and modulates autophagy, but the effects of unsaturated FAs such as oleate, which are also elevated during obesity, are less well understood. We therefore treated MIN6 cells and mouse islets for 8-48 h with either palmitate or oleate, and then monitored autophagic flux, signaling pathways, lysosomal biology, and phospholipid profiles. Compared with palmitate, oleate more effectively stimulated both autophagic flux and clearance of autophagosomes. The flux stimulation occurred independently of ER stress, nutrient-sensing (mTOR) and signaling pathways (protein kinases A, C, and D). Instead the mechanism involved the exchange factor directly activated by cAMP 2 (EPAC2). Oleate reduced cellular cAMP, and its effects on autophagic flux were reproduced or inhibited, respectively, by Epac2 knockdown or activation. Oleate also increased lysosomal acidity and increased phospholipid saturation, consistent with improved autophagosomal fusion with lysosomes. We conclude that a potent stimulation of autophagy might help explain the known benefits of unsaturated FAs in countering the toxicity of saturated FAs in β-cells during obesity and lipid loading.
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Affiliation(s)
- Kwan Yi Chu
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW 2052
| | - Liam O'Reilly
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010
| | - Natalie Mellet
- Baker IDI Heart and Diabetes Institute, Prahran, Victoria 3004, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Prahran, Victoria 3004, Australia
| | - Clarissa Bartley
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010
| | - Trevor J Biden
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010; St. Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW 2052.
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Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:6141902. [PMID: 30305865 PMCID: PMC6165581 DOI: 10.1155/2018/6141902] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/04/2018] [Indexed: 12/21/2022]
Abstract
Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.
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Yang SJ, Kwak SY, Jo G, Song TJ, Shin MJ. Serum metabolite profile associated with incident type 2 diabetes in Koreans: findings from the Korean Genome and Epidemiology Study. Sci Rep 2018; 8:8207. [PMID: 29844477 PMCID: PMC5974077 DOI: 10.1038/s41598-018-26320-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 05/03/2018] [Indexed: 02/07/2023] Open
Abstract
The identification of metabolic alterations in type 2 diabetes (T2D) is useful for elucidating the pathophysiology of the disease and in classifying high-risk individuals. In this study, we prospectively examined the associations between serum metabolites and T2D risk in a Korean community-based cohort (the Ansan-Ansung cohort). Data were obtained from 1,939 participants with available metabolic profiles and without diabetes, cardiovascular disease, or cancer at baseline. The acylcarnitine, amino acid, amine, and phospholipid levels in fasting serum samples were analyzed by targeted metabolomics. During the 8-year follow-up period, we identified 282 cases of incident T2D. Of all metabolites measured, 22 were significantly associated with T2D risk. Specifically, serum levels of alanine, arginine, isoleucine, proline, tyrosine, valine, hexose and five phosphatidylcholine diacyls were positively associated with T2D risk, whereas lyso-phosphatidylcholine acyl C17:0 and C18:2 and other glycerophospholipids were negatively associated with T2D risk. The associated metabolites were further correlated with T2D-relevant risk factors such as insulin resistance and triglyceride indices. In addition, a healthier diet (as measured by the modified recommended food score) was independently associated with T2D risk. Alterations of metabolites such as amino acids and choline-containing phospholipids appear to be associated with T2D risk in Korean adults.
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Affiliation(s)
- Soo Jin Yang
- Department of Food and Nutrition, Seoul Women's University, Seoul, 01797, Republic of Korea
| | - So-Young Kwak
- Department of Public Health Sciences, BK21PLUS Program in Embodiment: Health-Society Interaction, Graduate School, Korea University, Seoul, 02841, Republic of Korea
| | - Garam Jo
- Department of Public Health Sciences, BK21PLUS Program in Embodiment: Health-Society Interaction, Graduate School, Korea University, Seoul, 02841, Republic of Korea
| | - Tae-Jin Song
- Department of Neurology, Ewha Womans University School of Medicine, Seoul, 07985, Republic of Korea
| | - Min-Jeong Shin
- Department of Public Health Sciences, BK21PLUS Program in Embodiment: Health-Society Interaction, Graduate School, Korea University, Seoul, 02841, Republic of Korea.
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Ardestani A, Lupse B, Kido Y, Leibowitz G, Maedler K. mTORC1 Signaling: A Double-Edged Sword in Diabetic β Cells. Cell Metab 2018; 27:314-331. [PMID: 29275961 DOI: 10.1016/j.cmet.2017.11.004] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/11/2017] [Accepted: 11/15/2017] [Indexed: 12/21/2022]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a central regulator of metabolic and nutrient cues that integrates environmental inputs into downstream signaling pathways to control cellular metabolism, growth, and survival. While numerous in vitro and in vivo studies reported the positive functions of mTORC1 in the regulation of β cell survival and proliferation under physiological conditions, more recent work demonstrates the opposite in the long term; this is exemplified by the constitutive inappropriate hyper-activation of mTORC1 in diabetic islets or β cells under conditions of increased β cell stress and metabolic demands. These recent findings uncover mTORC1's importance as an emerging significant player in the development and progression of β cell failure in type 2 diabetes and suggest that mTORC1 may act as a "double edge sword" in the regulation of β cell mass and function in response to metabolic stress such as nutrient overload and insulin resistance.
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Affiliation(s)
- Amin Ardestani
- University of Bremen, Centre for Biomolecular Interactions Bremen, Bremen 28359, Germany.
| | - Blaz Lupse
- University of Bremen, Centre for Biomolecular Interactions Bremen, Bremen 28359, Germany
| | - Yoshiaki Kido
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; Division of Metabolism and Disease, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe 654-0142, Japan
| | - Gil Leibowitz
- Endocrinology and Metabolism Service and the Hadassah Diabetes Unit, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Kathrin Maedler
- University of Bremen, Centre for Biomolecular Interactions Bremen, Bremen 28359, Germany.
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Ye Q, Fu JF. Paediatric type 2 diabetes in China-Pandemic, progression, and potential solutions. Pediatr Diabetes 2018; 19:27-35. [PMID: 28326652 DOI: 10.1111/pedi.12517] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/06/2017] [Accepted: 02/09/2017] [Indexed: 02/06/2023] Open
Abstract
China is gradually taking its place as one of the world's economic giants and concurrently learning to cope with the burden of diseases that are more common in the developed world, such as paediatric type 2 diabetes mellitus. The prevalence of type 2 diabetes has been recently observed among children and adolescents in China; hence, there is a lack of information about the incidence, prevalence, pathogenesis, and pathophysiology of the disease. Diagnosis, treatment, and management have been standardized to a large degree, but there is still a need for data regarding optimal management protocols and how to achieve the best control over current state of the disease. The objective of this review is to consolidate the available information about paediatric diabetes, with a focus on the increasing prevalence of type 2 diabetes in Chinese youth. Here we emphasize the prevention strategies and have included literature with respect to pathogenesis, diagnosis, and treatment published in English and Chinese within the past 10 years.
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Affiliation(s)
- Qing Ye
- The Children's Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Jun-Fen Fu
- The Children's Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
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Peng M, Yang XF. Relationship between mTOR signaling pathway and hepatic stellate cells function. Shijie Huaren Xiaohua Zazhi 2017; 25:3141-3148. [DOI: 10.11569/wcjd.v25.i35.3141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The activation of hepatic stellate cells (HSCs) is generally considered to be the central link in the formation of hepatic fibrosis. Various factors can regulate the function of HSCs through multiple signaling pathways, of which the mammalian target of rapamycin (mTOR) signaling pathway is especially important. Elucidating the relationship between the mTOR signaling pathway and the proliferation, apoptosis, autophagy, and senescence of HSCs can provide new therapeutic targets and methods for the clinical treatment of hepatic fibrosis. This paper discusses the relationship between the mTOR signaling pathway and the function of HSCs.
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Affiliation(s)
- Min Peng
- Department of Gastroenterology, Affiliated Nanhua Hospital, University of South China, Hengyang 421002, Hunan Province, China
| | - Xue-Feng Yang
- Department of Gastroenterology, Affiliated Nanhua Hospital, University of South China, Hengyang 421002, Hunan Province, China
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27
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Raptor regulates functional maturation of murine beta cells. Nat Commun 2017; 8:15755. [PMID: 28598424 PMCID: PMC5472774 DOI: 10.1038/ncomms15755] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 04/26/2017] [Indexed: 02/08/2023] Open
Abstract
Diabetes is associated with beta cell mass loss and islet dysfunctions. mTORC1 regulates beta cell survival, proliferation and function in physiological and pathological conditions, such as pregnancy and pancreatectomy. Here we show that deletion of Raptor, which is an essential component of mTORC1, in insulin-expressing cells promotes hypoinsulinemia and glucose intolerance. Raptor-deficient beta cells display reduced glucose responsiveness and exhibit a glucose metabolic profile resembling fetal beta cells. Knockout islets have decreased expression of key factors of functional maturation and upregulation of neonatal markers and beta cell disallowed genes, resulting in loss of functional maturity. Mechanistically, Raptor-deficient beta cells show reduced expression of DNA-methyltransferase 3a and altered patterns of DNA methylation at loci that are involved in the repression of disallowed genes. The present findings highlight a novel role of mTORC1 as a core mechanism governing postnatal beta cell maturation and physiologic beta cell mass during adulthood. mTORC1 regulates beta cell survival, function and adaptation to physiologic and pathological stimuli. Here Ni et al. demonstrate that that deficiency of Raptor, a component of mTORC1 complex, impairs insulin secretion and glucose tolerance in mice by affecting maturation of beta cells during the postnatal period.
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Kovač J, Šutuš Temovski T, Rozmarič T, Horvat S, Beltram J, Trebušak Podkrajšek K, Battelino T, Kotnik P. DEPTOR promoter genetic variants and insulin resistance in obese children and adolescents. Pediatr Diabetes 2017; 18:152-158. [PMID: 26871578 DOI: 10.1111/pedi.12371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 01/14/2016] [Accepted: 12/03/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Insulin resistance (IR) is one of the major metabolic complications of obesity in children and adolescents. DEP domain-containing mammalian target of rapamycin interacting protein (DEPTOR) is involved in downstream insulin signaling and DEPTOR's effects are regulated by its level of expression. OBJECTIVES To analyze promoter region of DEPTOR for genetic variants associated with altered IR in obese children and adolescents. SUBJECTS AND METHODS IR was determined in 322 normoglycemic obese subjects [173 females, 149 males; mean age 13.3 ± 3.5 yr, mean BMI-SDS 2.85 ± 0.83, HbA1C 5.2 ± 0.2% (33 ± 2.5 mmol/mol)] using homeostatic model assessment - insulin resistance [HOMA-IR (>2 prepubertal and >3 pubertal)] and whole body insulin sensitivity index [WBISI (<6.5 prepubertal and <4.5 pubertal)]. Genetic variants, determined by high resolution melting analysis, were confirmed by Sanger sequencing, whereas population allele distribution was determined by TaqMan genotyping probes. RESULTS Genetic variant c.-143T>C (rs7840156) was associated with a significant 2-fold decreased risk to present with IR, determined by HOMA-IR [odds ratio (OR) = 0.614, 95% confidence interval (CI) = 0.435-0.867, p = 0.0057) and WBISI (OR = 0.582, 95% CI = 0.414-0.817, p = 0.0018). The CC genotype had lower mean HOMA-IR value (2.47 ± 0.44 vs. 3.04 ± 0.14, p = 0.0177) and higher mean WBISI value (7.00 ± 0.71 vs. 5.27 ± 0.33, p = 0.0235) than TT genotype. Variant c.-143T>C was located in evolutionary highly conserved region in DEPTOR promoter region. CONCLUSION Presented results on association between insulin sensitivity and genetic variants in DEPTOR gene suggest DEPTOR and mammalian target of rapamycin signaling pathway to be potential target for future research and pharmacological interventions.
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Affiliation(s)
- Jernej Kovač
- Unit of Special Laboratory Diagnostics, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Tamara Šutuš Temovski
- Unit of Special Laboratory Diagnostics, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Tomaž Rozmarič
- Unit of Special Laboratory Diagnostics, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Simon Horvat
- National Institute of Chemistry, Ljubljana, Slovenia.,Biotechnical faculty, University of Ljubljana, Ljubljana, Slovenia
| | | | - Katarina Trebušak Podkrajšek
- Unit of Special Laboratory Diagnostics, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tadej Battelino
- Department of Endocrinology, Diabetes and Metabolic Diseases, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Pediatrics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Primož Kotnik
- Department of Endocrinology, Diabetes and Metabolic Diseases, University Children's Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Pediatrics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Erdogan CS, Mørup-Lendal M, Dalgaard LT, Vang O. Sirtuin 1 independent effects of resveratrol in INS-1E β-cells. Chem Biol Interact 2017; 264:52-60. [PMID: 28108221 DOI: 10.1016/j.cbi.2017.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/22/2016] [Accepted: 01/16/2017] [Indexed: 11/26/2022]
Abstract
Resveratrol (Resv), a natural polyphenol, is suggested to have various health benefits including improved insulin sensitivity. Resv activates Sirtuin (Sirt1) in several species and tissues. Sirt1 is a protein deacetylase with an important role in ageing, metabolism and β-cell function. In insulinoma β-cells (INS-1E), Resv is previously shown to improve glucose-stimulated insulin secretion in a Sirt1-dependent mechanism and to protect against β-cell dedifferentiation in non-human primates, while inducing hypertrophy in myoblasts. Mammalian (mechanistic) Target of Rapamycin (mTOR), is a key regulator of cellular metabolism and regulates the cell size, β-cell survival and proliferation. In order to understand the interaction of Sirt1 and mTOR cascade activity with Resv-induced changes in the INS-1E cell line, we generated stable Sirt1-down-regulated INS-1E cells, and analysed Sirt1-dependent effects of Resv with respect to mTOR cascade activity. Sirt1-knockdown (KD) had a significant increase in cell size compared to negative-control (NEG CTR) cells. Resveratrol treatment increased cell size in both cell types in a dose-dependent manner at 24 h (Resv conc: 15-60 μM), and decreased the cell number (Resv conc: 30-60 μM). Cell area was increased in NEG CTR cells (Resv conc: 60 μM) at 24 h and KD cells at 48 h (Resv conc: 15-60 μM). Rapamycin, a specific mTOR inhibitor, counteracted the Resv-induced cell enlargement (both cell diameter and area). Furthermore, Sirt1-downregulation by itself did not affect the mTOR cascade activities as measured by Western blotting for total and phosphorylated Akt and mTOR. Rapamycin decreased the mTORC1 activity, while increasing the pAkt levels. Resveratrol did not interfere with the mTOR activity or with Sirt1 expression. Altogether, this work indicates that Sirt1 is a negative regulator of cell size. Moreover, the effect of Resv on cell size increase is mTOR-cascade dependent.
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Affiliation(s)
- Cihan S Erdogan
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | | | - Louise T Dalgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Ole Vang
- Department of Science and Environment, Roskilde University, Roskilde, Denmark.
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30
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Bouafir Y, Ait-Lounis A, Laraba-Djebari F. Improvement of function and survival of pancreatic beta-cells in streptozotocin-induced diabetic model by the scorpion venom fraction F1. TOXIN REV 2016. [DOI: 10.1080/15569543.2016.1260591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Yesmine Bouafir
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria
| | - Aouatef Ait-Lounis
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria
| | - Fatima Laraba-Djebari
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria
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31
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Cheng Q, Beltran VD, Chan SMH, Brown JR, Bevington A, Herbert TP. System-L amino acid transporters play a key role in pancreatic β-cell signalling and function. J Mol Endocrinol 2016; 56:175-87. [PMID: 26647387 DOI: 10.1530/jme-15-0212] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The branched-chain amino acids (BCAA) leucine, isoleucine and valine, are essential amino acids that play a critical role in cellular signalling and metabolism. They acutely stimulate insulin secretion and activate the regulatory serine/threonine kinase mammalian target of rapamycin complex 1 (mTORC1), a kinase that promotes increased β-cell mass and function. The effects of BCAA on cellular function are dependent on their active transport into the mammalian cells via amino acid transporters and thus the expression and activity of these transporters likely influence β-cell signalling and function. In this report, we show that the System-L transporters are required for BCAA uptake into clonal β-cell lines and pancreatic islets, and that these are essential for signalling to mTORC1. Further investigation revealed that the System-L amino acid transporter 1 (LAT1) is abundantly expressed in the islets, and that knockdown of LAT1 using siRNA inhibits mTORC1 signalling, leucine-stimulated insulin secretion and islet cell proliferation. In summary, we show that the LAT1 is required for regulating β-cell signalling and function in islets and thus may be a novel pharmacological/nutritional target for the treatment and prevention of type 2 diabetes.
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Affiliation(s)
- Qi Cheng
- Research School of BiologyAustralian National University, Acton, Australia
| | - Violeta D Beltran
- Department of InfectionImmunity and Inflammation, University of Leicester, UK
| | - Stanley M H Chan
- Health Innovations Research Institute (HIRI)School of Medical Sciences, RMIT University, Bundoora, Australia
| | - Jeremy R Brown
- Department of InfectionImmunity and Inflammation, University of Leicester, UK
| | - Alan Bevington
- Department of InfectionImmunity and Inflammation, University of Leicester, UK
| | - Terence P Herbert
- Health Innovations Research Institute (HIRI)School of Medical Sciences, RMIT University, Bundoora, Australia
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32
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Branched-chain and aromatic amino acid profiles and diabetes risk in Chinese populations. Sci Rep 2016; 6:20594. [PMID: 26846565 PMCID: PMC4742847 DOI: 10.1038/srep20594] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/07/2016] [Indexed: 12/12/2022] Open
Abstract
Recent studies revealed strong evidence that branched-chain and aromatic amino acids (BCAAs and AAAs) are closely associated with the risk of developing type 2 diabetes in several Western countries. The aim of this study was to evaluate the potential role of BCAAs and AAAs in predicting the diabetes development in Chinese populations. The serum levels of valine, leucine, isoleucine, tyrosine, and phenylalanine were measured in a longitudinal and a cross sectional studies with a total of 429 Chinese participants at different stages of diabetes development, using an ultra-performance liquid chromatography triple quadruple mass spectrometry platform. The alterations of the five AAs in Chinese populations are well in accordance with previous reports. Early elevation of the five AAs and their combined score was closely associated with future development of diabetes, suggesting an important role of these metabolites as early markers of diabetes. On the other hand, the five AAs were not as good as existing clinical markers in differentiating diabetic patients from their healthy counterparts. Our findings verified the close correlation of BCAAs and AAAs with insulin resistance and future development of diabetes in Chinese populations and highlighted the predictive value of these markers for future development of diabetes.
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Yang Z, Liu F, Qu H, Wang H, Xiao X, Deng H. 1, 25(OH)2D3 protects β cell against high glucose-induced apoptosis through mTOR suppressing. Mol Cell Endocrinol 2015. [PMID: 26213322 DOI: 10.1016/j.mce.2015.07.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetes mellitus is a leading cause of death and disability worldwide, which presents a serious public health crisis in China nowadays. It has been well recognized that excessive β-cell apoptosis is the key pathogenesis of diabetes, of which the mammalian target of rapamycin (mTOR) serves as the critical signaling pathway. Emerging evidence indicates that vitamin D deficiency acts as a potential risk factor for diabetes. The present study aims to test the hypothesis that 1 alpha, 25-dihydroxyvitamin D(3) [1, 25(OH)2D3] can inhibit β-cell apoptosis via the suppression of mTOR signaling pathway. β-cells (INS-1) were cultured in the context of normal glucose or high glucose media with or without 1, 25(OH)2D3 treatment. β-cell apoptosis was evaluated by inverted fluorescence microscope, flow cytometry and electron microscope, respectively. Quantitative RT-PCR and Western blotting were performed to assess the possible perturbations in mTOR signaling pathway. High glucose significantly increased β-cell apoptosis. Of importance, RT-PCR and Western blotting demonstrated that high glucose inhibited DNA-damage-inducible transcript 4 (DDIT4) and TSC1/TSC2, up-regulated Rheb/mTOR/p70S6K and enhanced expression of the apoptosis regulating proteins, such as phospho-Bcl-2, cytochrome C and cleaved caspase. Interestingly, 1, 25(OH)2D3 treatment reversed high glucose induced pathological changes in mTOR signaling pathway, restored expression of DDIT4 and TSC1/TSC2, blocked aberrant up-regulation of Rheb/mTOR/p70S6K and the apoptosis regulating proteins, and effectively inhibited β-cell apoptosis. Therefore, 1, 25(OH)2D3 treatment can effectively protects β cell against high glucose-induced apoptosis mainly via the suppression of mTOR signaling pathway, which may be considered as a potential therapy for patients with diabetes.
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Affiliation(s)
- Zesong Yang
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China
| | - Fang Liu
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China
| | - Hua Qu
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China
| | - Hang Wang
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China
| | - Xiaoqiu Xiao
- Laboratory of Lipid and Glucose Metabolism, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China
| | - Huacong Deng
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, PR China.
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Gui YS, Wang L, Tian X, Li X, Ma A, Zhou W, Zeng N, Zhang J, Cai B, Zhang H, Chen JY, Xu KF. mTOR Overactivation and Compromised Autophagy in the Pathogenesis of Pulmonary Fibrosis. PLoS One 2015; 10:e0138625. [PMID: 26382847 PMCID: PMC4575195 DOI: 10.1371/journal.pone.0138625] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/31/2015] [Indexed: 01/13/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway in pulmonary fibrosis was investigated in cell and animal models. mTOR overactivation in alveolar epithelial cells (AECs) was achieved in the conditional and inducible Tsc1 knock-down mice SPC-rtTA/TetO-Cre/Tsc1fx/+ (STT). Doxycycline caused Tsc1 knock-down and consequently mTOR activation in AECs for the STT mice. Mice treated with bleomycin exhibited increased mortality and pulmonary fibrosis compared with control mice. In wild-type C57BL/6J mice, pretreatment with rapamycin attenuated the bleomycin-mediated mortality and fibrosis. Rapamycin-mediated mouse survival benefit was inhibited by chloroquine, an autophagy inhibitor. Autophagosomes were decreased in the lungs after bleomycin exposure. Rapamycin induced the production of autophagosomes and diminished p62. We concluded that mTOR overactivation in AECs and compromised autophagy in the lungs are involved in the pathogenesis of pulmonary fibrosis. The suppression of mTOR and enhancement of autophagy may be used for treatment of pulmonary fibrosis.
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Affiliation(s)
- Yao-Song Gui
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Lianmei Wang
- State Key Laboratory of Medical Molecular Biology, Department of Physiology and Pathophysiology, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xinlun Tian
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xue Li
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Aiping Ma
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Weixun Zhou
- Department of Pathology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ni Zeng
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ji Zhang
- Department of Thoracic Surgery, Wuxi People’s Hospital affiliated to Nanjing Medical University, Wuxi, China
| | - Baiqiang Cai
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Hongbing Zhang
- State Key Laboratory of Medical Molecular Biology, Department of Physiology and Pathophysiology, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Jing-Yu Chen
- Department of Thoracic Surgery, Wuxi People’s Hospital affiliated to Nanjing Medical University, Wuxi, China
- * E-mail: (JYC); (KFX)
| | - Kai-Feng Xu
- Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- * E-mail: (JYC); (KFX)
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Carter G, Miladinovic B, Patel AA, Deland L, Mastorides S, Patel NA. Circulating long noncoding RNA GAS5 levels are correlated to prevalence of type 2 diabetes mellitus. BBA CLINICAL 2015; 4:102-7. [PMID: 26675493 PMCID: PMC4661729 DOI: 10.1016/j.bbacli.2015.09.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/03/2015] [Accepted: 09/08/2015] [Indexed: 12/16/2022]
Abstract
Background Diabetes mellitus (DM), a metabolic disease, is characterized by impaired fasting glucose levels. Type 2 DM is adult onset diabetes. Long non-coding RNAs (lncRNAs) regulate gene expression and multiple studies have linked lncRNAs to human diseases. Methods Serum samples obtained from 96 participating veterans at JAH VA were deposited in the Research Biospecimen Repository. We used a two-stage strategy to identify an lncRNA whose levels correlated with T2DM. Initially we screened five serum samples from diabetic and non-diabetic individuals using lncRNA arrays. Next, GAS5 lncRNA levels were analyzed in 96 serum samples using quantitative PCR. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff GAS5 for diagnosis of DM. Results Our results demonstrate that decreased GAS5 levels in serum were associated with diabetes in a cohort of US military veterans. The ROC analysis revealed an optimal cutoff GAS5 value of less than or equal to 10. qPCR results indicated that individuals with absolute GAS5 < 10 ng/μl have almost twelve times higher odds of having diabetes (Exact Odds Ratio [OR] = 11.79 (95% CI: 3.97, 37.26), p < 0.001). Analysis indicated area under curve (AUC) of ROC of 0.81 with 85.1% sensitivity and 67.3% specificity in distinguishing non-diabetic from diabetic subjects. The positive predictive value is 71.4%. Conclusion lncRNA GAS5 levels are correlated to prevalence of T2DM. General Significance Assessment of GAS5 in serum along with other parameters offers greater accuracy in identifying individuals at-risk for diabetes. Serum samples from participating veterans were analyzed. Levels of serum lncRNAs were analyzed for correlation to diabetes. ROC analysis was performed to determine GAS5 optimal cutoff. Individuals with absolute GAS5 < 10 ng/μl have almost 12 times higher odds of diabetes. We identified GAS5 lncRNA as significant indicator of diabetes.
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Affiliation(s)
- Gay Carter
- James A. Haley Veterans Hospital, Tampa, FL 33612, United States
| | | | | | - Lauren Deland
- James A. Haley Veterans Hospital, Tampa, FL 33612, United States
| | | | - Niketa A Patel
- James A. Haley Veterans Hospital, Tampa, FL 33612, United States ; University of South Florida, Tampa, FL 33612, United States
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Bartolomé A, Kimura-Koyanagi M, Asahara SI, Guillén C, Inoue H, Teruyama K, Shimizu S, Kanno A, García-Aguilar A, Koike M, Uchiyama Y, Benito M, Noda T, Kido Y. Pancreatic β-cell failure mediated by mTORC1 hyperactivity and autophagic impairment. Diabetes 2014; 63:2996-3008. [PMID: 24740570 DOI: 10.2337/db13-0970] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hyperactivation of the mammalian target of rapamycin complex 1 (mTORC1) in β-cells is usually found as a consequence of increased metabolic load. Although it plays an essential role in β-cell compensatory mechanisms, mTORC1 negatively regulates autophagy. Using a mouse model with β-cell-specific deletion of Tsc2 (βTsc2(-/-)) and, consequently, mTORC1 hyperactivation, we focused on the role that chronic mTORC1 hyperactivation might have on β-cell failure. mTORC1 hyperactivation drove an early increase in β-cell mass that later declined, triggering hyperglycemia. Apoptosis and endoplasmic reticulum stress markers were found in islets of older βTsc2(-/-) mice as well as accumulation of p62/SQSTM1 and an impaired autophagic response. Mitochondrial mass was increased in β-cells of βTsc2(-/-) mice, but mitophagy was also impaired under these circumstances. We provide evidence of β-cell autophagy impairment as a link between mTORC1 hyperactivation and mitochondrial dysfunction that probably contributes to β-cell failure.
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Affiliation(s)
- Alberto Bartolomé
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
| | - Maki Kimura-Koyanagi
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shun-Ichiro Asahara
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Carlos Guillén
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
| | - Hiroyuki Inoue
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Kyoko Teruyama
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Shinobu Shimizu
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Ayumi Kanno
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ana García-Aguilar
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
| | - Masato Koike
- Department of Cell Biology and Neurosciences, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cell Biology and Neurosciences, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Manuel Benito
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain CIBERDEM, Instituto de Salud Carlos III, Madrid, Spain
| | - Tetsuo Noda
- Department of Cell Biology, Cancer Institute, Japanese Foundation of Cancer Research, Tokyo, Japan
| | - Yoshiaki Kido
- Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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Xie J, El Sayed NM, Qi C, Zhao X, Moore CE, Herbert TP. Exendin-4 stimulates islet cell replication via the IGF1 receptor activation of mTORC1/S6K1. J Mol Endocrinol 2014; 53:105-15. [PMID: 24994913 DOI: 10.1530/jme-13-0200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glucagon-like peptide 1 receptor (GLP1R) agonists, such as exendin-4, potentiate glucose-stimulated insulin secretion and are currently used in the management of type 2 diabetes. Interestingly, GLP1R agonists also have the ability to augment β-cell mass. In this report, we provide evidence that in the presence of glucose, exendin-4 stimulates rodent islet cell DNA replication via the activation of ribosomal protein S6 kinase 1 (S6K1) and that this is mediated by the protein kinase B (PKB)-dependent activation of mTOR complex 1 (mTORC1). We show that activation of this pathway is caused by the autocrine or paracrine activation of the IGF1 receptor (IGF1R), as siRNA-mediated knockdown of the IGF1R effectively blocked exendin-4-stimulated PKB and mTORC1 activation. In contrast, pharmacological inactivation of the epidermal growth factor receptor has no discernible effect on exendin-4-stimulated PKB or mTORC1 activation. Therefore, we conclude that GLP1R agonists stimulate β-cell proliferation via the PKB-dependent stimulation of mTORC1/S6K1 whose activation is mediated through the autocrine/paracrine activation of the IGF1R. This work provides a better understanding of the molecular basis of GLP1 agonist-induced β-cell proliferation which could potentially be exploited in the identification of novel drug targets that increase β-cell mass.
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Affiliation(s)
- Jianling Xie
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Norhan M El Sayed
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Cheng Qi
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Xuechan Zhao
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Claire E Moore
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Terence P Herbert
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
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38
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Plaisance V, Waeber G, Regazzi R, Abderrahmani A. Role of microRNAs in islet beta-cell compensation and failure during diabetes. J Diabetes Res 2014; 2014:618652. [PMID: 24734255 PMCID: PMC3964735 DOI: 10.1155/2014/618652] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/24/2014] [Indexed: 12/12/2022] Open
Abstract
Pancreatic beta-cell function and mass are markedly adaptive to compensate for the changes in insulin requirement observed during several situations such as pregnancy, obesity, glucocorticoids excess, or administration. This requires a beta-cell compensation which is achieved through a gain of beta-cell mass and function. Elucidating the physiological mechanisms that promote functional beta-cell mass expansion and that protect cells against death, is a key therapeutic target for diabetes. In this respect, several recent studies have emphasized the instrumental role of microRNAs in the control of beta-cell function. MicroRNAs are negative regulators of gene expression, and are pivotal for the control of beta-cell proliferation, function, and survival. On the one hand, changes in specific microRNA levels have been associated with beta-cell compensation and are triggered by hormones or bioactive peptides that promote beta-cell survival and function. Conversely, modifications in the expression of other specific microRNAs contribute to beta-cell dysfunction and death elicited by diabetogenic factors including, cytokines, chronic hyperlipidemia, hyperglycemia, and oxidized LDL. This review underlines the importance of targeting the microRNA network for future innovative therapies aiming at preventing the beta-cell decline in diabetes.
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Affiliation(s)
- Valérie Plaisance
- Lille 2 University, European Genomic Institute for Diabetes (EGID), FR 3508, UMR-8199 Lille, France
| | - Gérard Waeber
- Service of Internal Medicine, Hospital-University of Lausanne (CHUV), 1011 Lausanne, Switzerland
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | - Amar Abderrahmani
- Lille 2 University, European Genomic Institute for Diabetes (EGID), FR 3508, UMR-8199 Lille, France
- *Amar Abderrahmani:
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Dalbøge LS, Almholt DLC, Neerup TSR, Vassiliadis E, Vrang N, Pedersen L, Fosgerau K, Jelsing J. Characterisation of age-dependent beta cell dynamics in the male db/db mice. PLoS One 2013; 8:e82813. [PMID: 24324833 PMCID: PMC3855780 DOI: 10.1371/journal.pone.0082813] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 11/06/2013] [Indexed: 12/20/2022] Open
Abstract
Aim To characterise changes in pancreatic beta cell mass during the development of diabetes in untreated male C57BLKS/J db/db mice. Methods Blood samples were collected from a total of 72 untreated male db/db mice aged 5, 6, 8, 10, 12, 14, 18, 24 and 34 weeks, for measurement of terminal blood glucose, HbA1c, plasma insulin, and C-peptide. Pancreata were removed for quantification of beta cell mass, islet numbers as well as proliferation and apoptosis by immunohistochemistry and stereology. Results Total pancreatic beta cell mass increased significantly from 2.1 ± 0.3 mg in mice aged 5 weeks to a peak value of 4.84 ± 0.26 mg (P < 0.05) in 12-week-old mice, then gradually decreased to 3.27 ± 0.44 mg in mice aged 34 weeks. Analysis of islets in the 5-, 10-, and 24-week age groups showed increased beta cell proliferation in the 10-week-old animals whereas a low proliferation is seen in older animals. The expansion in beta cell mass was driven by an increase in mean islet mass as the total number of islets was unchanged in the three groups. Conclusions/Interpretation The age-dependent beta cell dynamics in male db/db mice has been described from 5-34 weeks of age and at the same time alterations in insulin/glucose homeostasis were assessed. High beta cell proliferation and increased beta cell mass occur in young animals followed by a gradual decline characterised by a low beta cell proliferation in older animals. The expansion of beta cell mass was caused by an increase in mean islet mass and not islet number.
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Affiliation(s)
| | | | - Trine S. R. Neerup
- Department of Research and Development, Zealand Pharma A/S, Glostrup, Denmark
| | | | - Niels Vrang
- Department of Histology, Gubra ApS, Hørsholm, Denmark
| | - Lars Pedersen
- Department of Stereology, Visiopharm, Hørsholm, Denmark
| | - Keld Fosgerau
- Department of Research and Development, Zealand Pharma A/S, Glostrup, Denmark
| | - Jacob Jelsing
- Department of Histology, Gubra ApS, Hørsholm, Denmark
- * E-mail:
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40
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Nesca V, Guay C, Jacovetti C, Menoud V, Peyot ML, Laybutt DR, Prentki M, Regazzi R. Identification of particular groups of microRNAs that positively or negatively impact on beta cell function in obese models of type 2 diabetes. Diabetologia 2013; 56:2203-12. [PMID: 23842730 DOI: 10.1007/s00125-013-2993-y] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/19/2013] [Indexed: 01/11/2023]
Abstract
AIMS/HYPOTHESIS MicroRNAs are key regulators of gene expression involved in health and disease. The goal of our study was to investigate the global changes in beta cell microRNA expression occurring in two models of obesity-associated type 2 diabetes and to assess their potential contribution to the development of the disease. METHODS MicroRNA profiling of pancreatic islets isolated from prediabetic and diabetic db/db mice and from mice fed a high-fat diet was performed by microarray. The functional impact of the changes in microRNA expression was assessed by reproducing them in vitro in primary rat and human beta cells. RESULTS MicroRNAs differentially expressed in both models of obesity-associated type 2 diabetes fall into two distinct categories. A group including miR-132, miR-184 and miR-338-3p displays expression changes occurring long before the onset of diabetes. Functional studies indicate that these expression changes have positive effects on beta cell activities and mass. In contrast, modifications in the levels of miR-34a, miR-146a, miR-199a-3p, miR-203, miR-210 and miR-383 primarily occur in diabetic mice and result in increased beta cell apoptosis. These results indicate that obesity and insulin resistance trigger adaptations in the levels of particular microRNAs to allow sustained beta cell function, and that additional microRNA deregulation negatively impacting on insulin-secreting cells may cause beta cell demise and diabetes manifestation. CONCLUSIONS/INTERPRETATION We propose that maintenance of blood glucose homeostasis or progression toward glucose intolerance and type 2 diabetes may be determined by the balance between expression changes of particular microRNAs.
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Affiliation(s)
- Valeria Nesca
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 9, CH-1005 Lausanne, Switzerland
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41
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Galat A. Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands. Cell Mol Life Sci 2013; 70:3243-75. [PMID: 23224428 PMCID: PMC11113493 DOI: 10.1007/s00018-012-1206-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 10/24/2012] [Accepted: 10/25/2012] [Indexed: 12/25/2022]
Abstract
From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence-structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.
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Affiliation(s)
- Andrzej Galat
- Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Biologie et de Technologies de Saclay, Service d'Ingénierie Moléculaire des Protéines, Bat. 152, 91191, Gif-sur-Yvette Cedex, France.
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42
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Abstract
In healthy individuals, insulin resistance is associated with physiological conditions such as pregnancy or body weight gain and triggers an increase in beta cell number and insulin secretion capacity to preserve normoglycaemia. Failure of this beta cell compensation capacity is a fundamental cause of diabetic hyperglycaemia. Incomplete understanding of the molecular mechanisms controlling the plasticity of adult beta cells mechanisms and how these cells fail during the pathogenesis of diabetes strongly limits the ability to develop new beta cell-specific therapies. Here, current knowledge of the signalling pathways controlling beta cell plasticity is reviewed, and possible directions for future research are discussed.
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Affiliation(s)
- B Thorens
- Center for Integrative Genomics, University of Lausanne, Switzerland.
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43
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Barlow AD, Nicholson ML, Herbert TP. Evidence for rapamycin toxicity in pancreatic β-cells and a review of the underlying molecular mechanisms. Diabetes 2013; 62:2674-82. [PMID: 23881200 PMCID: PMC3717855 DOI: 10.2337/db13-0106] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Rapamycin is used frequently in both transplantation and oncology. Although historically thought to have little diabetogenic effect, there is growing evidence of β-cell toxicity. This Review draws evidence for rapamycin toxicity from clinical studies of islet and renal transplantation, and of rapamycin as an anticancer agent, as well as from experimental studies. Together, these studies provide evidence that rapamycin has significant detrimental effects on β-cell function and survival and peripheral insulin resistance. The mechanism of action of rapamycin is via inhibition of mammalian target of rapamycin (mTOR). This Review describes the complex mTOR signaling pathways, which control vital cellular functions including mRNA translation, cell proliferation, cell growth, differentiation, angiogenesis, and apoptosis, and examines molecular mechanisms for rapamycin toxicity in β-cells. These mechanisms include reductions in β-cell size, mass, proliferation and insulin secretion alongside increases in apoptosis, autophagy, and peripheral insulin resistance. These data bring into question the use of rapamycin as an immunosuppressant in islet transplantation and as a second-line agent in other transplant recipients developing new-onset diabetes after transplantation with calcineurin inhibitors. It also highlights the importance of close monitoring of blood glucose levels in patients taking rapamycin as an anticancer treatment, particularly those with preexisting glucose intolerance.
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Affiliation(s)
- Adam D Barlow
- Department of Transplant Surgery, University Hospitals of Leicester, Leicester, UK.
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Harcourt BE, Penfold SA, Forbes JM. Coming full circle in diabetes mellitus: from complications to initiation. Nat Rev Endocrinol 2013; 9:113-23. [PMID: 23296171 DOI: 10.1038/nrendo.2012.236] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Glycaemic control, reduction of blood pressure using agents that block the renin-angiotensin system and control of dyslipidaemia are the major strategies used in the clinical management of patients with diabetes mellitus. Each of these approaches interrupts a number of pathological pathways, which directly contributes to the vascular complications of diabetes mellitus, including renal disease, blindness, neuropathy and cardiovascular disease. However, research published over the past few years has indicated that many of the pathological pathways important in the development of the vascular complications of diabetes mellitus are equally relevant to the initiation of diabetes mellitus itself. These pathways include insulin signalling, generation of cellular energy, post-translational modifications and redox imbalances. This Review will examine how the development of diabetes mellitus has come full circle from initiation to complications and suggests that the development of diabetes mellitus and the progression to chronic complications both require the same mechanistic triggers.
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Affiliation(s)
- Brooke E Harcourt
- Glycation and Diabetes Complications, Mater Medical Research Institute, Raymond Terrace, South Brisbane, QLD, Australia
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45
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Miao XY, Gu ZY, Liu P, Hu Y, Li L, Gong YP, Shu H, Liu Y, Li CL. The human glucagon-like peptide-1 analogue liraglutide regulates pancreatic beta-cell proliferation and apoptosis via an AMPK/mTOR/P70S6K signaling pathway. Peptides 2013; 39:71-9. [PMID: 23116613 DOI: 10.1016/j.peptides.2012.10.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 10/15/2012] [Accepted: 10/22/2012] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide-1 (GLP-1), an effective therapeutic agent for the treatment of diabetes, has been proven to protect pancreatic beta cells through many pathways. Recent evidence demonstrates that AMP-activated protein kinase (AMPK), as a metabolic regulator, coordinates beta-cell protein synthesis through regulation of the mammalian target of rapamycin (mTOR) signaling pathway. The purpose of the present study was to explore whether liraglutide, a human GLP-1 analogue, protects beta cells via AMPK/mTOR signaling. We evaluated INS-1 beta-cell line proliferation using the Cell Counting Kit-8, and examined the effect of GLP-1 on cellular ATP levels using an ATP assay kit. mTOR pathway protein expression levels were tested by Western blotting and glucolipotoxicity-induced cell apoptosis was evaluated by flow cytometry. Liraglutide increased beta-cell viability at an optimum concentration of 100 nmol/L in the presence of 11.1 or 30 mmol/L glucose. Liraglutide (100 nmol/L) activated mTOR and its downstream effectors, 70-kDa ribosomal protein S6 kinase and eIF4E-binding protein-1, in INS-1 cells. This effect was abated by pathway blockers: the AMPK activator AICAR and the mTOR inhibitor rapamycin. Furthermore, the effect of liraglutide on beta-cell proliferation was inhibited by AICAR and rapamycin. Liraglutide increased cellular ATP levels. In addition, liraglutide protected beta cells from glucolipotoxicity-induced apoptosis. This response was also prevented by rapamycin treatment. These results suggest that the enhancement of beta-cell proliferation by that GLP-1 receptor agonist liraglutide is mediated, at least in part, by AMPK/mTOR signaling. Liraglutide also prevents beta-cell glucolipotoxicity by activating mTOR.
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Affiliation(s)
- Xin-Yu Miao
- Department of Geriatric Endocrinology, General Hospital of PLA, 100853 Beijing, China
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Kaeberlein M. mTOR Inhibition: From Aging to Autism and Beyond. SCIENTIFICA 2013; 2013:849186. [PMID: 24379984 PMCID: PMC3860151 DOI: 10.1155/2013/849186] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/27/2013] [Indexed: 05/10/2023]
Abstract
The mechanistic target of rapamycin (mTOR) is a highly conserved protein that regulates growth and proliferation in response to environmental and hormonal cues. Broadly speaking, organisms are constantly faced with the challenge of interpreting their environment and making a decision between "grow or do not grow." mTOR is a major component of the network that makes this decision at the cellular level and, to some extent, the tissue and organismal level as well. Although overly simplistic, this framework can be useful when considering the myriad functions ascribed to mTOR and the pleiotropic phenotypes associated with genetic or pharmacological modulation of mTOR signaling. In this review, I will consider mTOR function in this context and attempt to summarize and interpret the growing body of literature demonstrating interesting and varied effects of mTOR inhibitors. These include robust effects on a multitude of age-related parameters and pathologies, as well as several other processes not obviously linked to aging or age-related disease.
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Affiliation(s)
- Matt Kaeberlein
- Department of Pathology, University of Washington, 1959 NE Pacific Street, D-514, Seattle, WA 98195-7470, USA
- *Matt Kaeberlein:
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Barlow AD, Xie J, Moore CE, Campbell SC, Shaw JAM, Nicholson ML, Herbert TP. Rapamycin toxicity in MIN6 cells and rat and human islets is mediated by the inhibition of mTOR complex 2 (mTORC2). Diabetologia 2012; 55:1355-65. [PMID: 22314813 PMCID: PMC3328678 DOI: 10.1007/s00125-012-2475-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 01/09/2012] [Indexed: 11/05/2022]
Abstract
AIMS/HYPOTHESIS Rapamycin (sirolimus) is one of the primary immunosuppressants for islet transplantation. Yet there is evidence that the long-term treatment of islet-transplant patients with rapamycin may be responsible for subsequent loss of islet graft function and viability. Therefore, the primary objective of this study was to elucidate the molecular mechanism of rapamycin toxicity in beta cells. METHODS Experiments were performed on isolated rat and human islets of Langerhans and MIN6 cells. The effects of rapamycin and the roles of mammalian target of rapamycin complex 2 (mTORC2)/protein kinase B (PKB) on beta cell signalling, function and viability were investigated using cell viability assays, insulin ELISA assays, kinase assays, western blotting, pharmacological inhibitors, small interfering (si)RNA and through the overproduction of a constitutively active mutant of PKB. RESULTS Rapamycin treatment of MIN6 cells and islets of Langerhans resulted in a loss of cell function and viability. Although rapamycin acutely inhibited mTOR complex 1 (mTORC1), the toxic effects of rapamycin were more closely correlated to the dissociation and inactivation of mTORC2 and the inhibition of PKB. Indeed, the overproduction of constitutively active PKB protected islets from rapamycin toxicity whereas the inhibition of PKB led to a loss of cell viability. Moreover, the selective inactivation of mTORC2 using siRNA directed towards rapamycin-insensitive companion of target of rapamycin (RICTOR), mimicked the toxic effects of chronic rapamycin treatment. CONCLUSIONS/INTERPRETATION This report provides evidence that rapamycin toxicity is mediated by the inactivation of mTORC2 and the inhibition of PKB and thus reveals the molecular basis of rapamycin toxicity and the essential role of mTORC2 in maintaining beta cell function and survival.
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Affiliation(s)
- A. D. Barlow
- Transplant Surgery Group, Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - J. Xie
- Department of Cell Physiology and Pharmacology, University of Leicester, The Henry Wellcome Building, University Road, Leicester, LE1 9HN UK
| | - C. E. Moore
- Department of Cell Physiology and Pharmacology, University of Leicester, The Henry Wellcome Building, University Road, Leicester, LE1 9HN UK
| | - S. C. Campbell
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
| | - J. A. M. Shaw
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
| | - M. L. Nicholson
- Transplant Surgery Group, Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - T. P. Herbert
- Department of Cell Physiology and Pharmacology, University of Leicester, The Henry Wellcome Building, University Road, Leicester, LE1 9HN UK
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