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Hai Y, Ren K, Zhang Y, Yang L, Cao H, Yuan X, Su L, Li H, Feng X, Liu D. HIF-1α serves as a co-linker between AD and T2DM. Biomed Pharmacother 2024; 171:116158. [PMID: 38242039 DOI: 10.1016/j.biopha.2024.116158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/21/2024] Open
Abstract
Alzheimer's disease (AD)-related brain deterioration is linked to the type 2 diabetes mellitus (T2DM) features hyperglycemia, hyperinsulinemia, and insulin resistance. Hypoxia as a common risk factor for both AD and T2DM. Hypoxia-inducible factor-1 alpha (HIF-1α) acts as the main regulator of the hypoxia response and may be a key target in the comorbidity of AD and T2DM. HIF-1α expression is closely related to hyperglycemia, insulin resistance, and inflammation. Tissue oxygen consumption disrupts HIF-1α homeostasis, leading to increased reactive oxygen species levels and the inhibition of insulin receptor pathway activity, causing neuroinflammation, insulin resistance, abnormal Aβ deposition, and tau hyperphosphorylation. HIF-1α activation also leads to the deposition of Aβ by promoting the abnormal shearing of amyloid precursor protein and inhibiting the degradation of Aβ, and it promotes tau hyperphosphorylation by activating oxidative stress and the activation of astrocytes, which further exasperates AD. Therefore, we believe that HIF-α has great potential as a target for the treatment of AD. Importantly, the intracellular homeostasis of HIF-1α is a more crucial factor than its expression level.
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Affiliation(s)
- Yang Hai
- Scientific Research and Experimental Center, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China; Key Laboratory of Dunhuang Medicine, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China.
| | - Ke Ren
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Yarong Zhang
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Lili Yang
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Haoshi Cao
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Xianxia Yuan
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Linling Su
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Hailong Li
- The First Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Xiaoli Feng
- Scientific Research and Experimental Center, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China; Key Laboratory of Dunhuang Medicine, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China
| | - Dongling Liu
- School of Pharmacy, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, PR China; Northwest Collaborative Innovation Center for Traditional Chinese Medicine, Lanzhou 730000, Gansu Province, PR China; Gansu Pharmaceutical Industry Innovation Research Institute, Lanzhou 730000, Gansu Province, PR China.
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2
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Mukai E, Fujimoto S, Inagaki N. Role of Reactive Oxygen Species in Glucose Metabolism Disorder in Diabetic Pancreatic β-Cells. Biomolecules 2022; 12:biom12091228. [PMID: 36139067 PMCID: PMC9496160 DOI: 10.3390/biom12091228] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
The dysfunction of pancreatic β-cells plays a central role in the onset and progression of type 2 diabetes mellitus (T2DM). Insulin secretory defects in β-cells are characterized by a selective impairment of glucose stimulation, and a reduction in glucose-induced ATP production, which is essential for insulin secretion. High glucose metabolism for insulin secretion generates reactive oxygen species (ROS) in mitochondria. In addition, the expression of antioxidant enzymes is very low in β-cells. Therefore, β-cells are easily exposed to oxidative stress. In islet studies using a nonobese T2DM animal model that exhibits selective impairment of glucose-induced insulin secretion (GSIS), quenching ROS generated by glucose stimulation and accumulated under glucose toxicity can improve impaired GSIS. Acute ROS generation and toxicity cause glucose metabolism disorders through different molecular mechanisms. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is a master regulator of antioxidant defense and a potential therapeutic target in oxidative stress-related diseases, suggesting the possible involvement of Nrf2 in β-cell dysfunction caused by ROS. In this review, we describe the mechanisms of insulin secretory defects induced by oxidative stress in diabetic β-cells.
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Affiliation(s)
- Eri Mukai
- Medical Physiology and Metabolism Laboratory, Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kusatsu 5258577, Japan
- Correspondence:
| | - Shimpei Fujimoto
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi 7838505, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto 6068507, Japan
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3
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Bitter melon fruit extract enhances intracellular ATP production and insulin secretion from rat pancreatic β-cells. Br J Nutr 2021; 127:377-383. [PMID: 33762029 DOI: 10.1017/s0007114521001082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bitter melon (Momordica charantia L.) has been shown to have various health-promoting activities, including antidiabetic and hypoglycaemic effects. Improvement in insulin sensitivity and increase in glucose utilisation in peripheral tissues have been reported, but the effect on insulin secretion from pancreatic β-cells remains unclear. In this study, we investigated the effect of bitter melon fruit on insulin secretion from β-cells and the underlying mechanism. The green fruit of bitter melon was freeze-dried and extracted with methanol. The bitter melon fruit extract (BMFE) was fractionated using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). Insulin secretory capacity from INS-1 rat insulinoma cell line and rat pancreatic islets, as well as glucose tolerance in rats by oral glucose tolerance test (OGTT), was measured using BMFE and fractions. ATP production in β-cells was also examined. BMFE augmented insulin secretion from INS-1 cells in a dose-dependent manner. The significant augmentation of insulin secretion was independent of the glucose dose. Fraction A (i.e. hydrophobic fraction), but not fractions B and C, augmented insulin secretion significantly at the same level as that by BMFE. This finding was also observed in pancreatic islets. In OGTT, BMFE and fraction A decreased blood glucose levels and increased serum insulin levels after glucose loading. The decrease in blood glucose levels was also observed in streptozotocin-induced diabetic rats. In addition, BMFE and fraction A increased the ATP content in β-cells. We concluded that hydrophobic components of BMFE increase ATP production and augment insulin secretion from β-cells, consequently decreasing blood glucose levels.
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4
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Fujimoto S. Novel mechanism of impaired metabolism-secretion coupling in β-cells: Loss of cytosolic adenosine triphosphate by leakage. J Diabetes Investig 2019; 10:1401-1404. [PMID: 31168903 PMCID: PMC6825920 DOI: 10.1111/jdi.13094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 01/18/2023] Open
Abstract
Zhang et al. recently proposed a new mechanism of metabolism‐secretion coupling impairment in diabetic β‐cells involving the loss of cytosolic adenosine triphosphate by leakage through plasma membrane. Hyperglycemia increases mistargeting expression of the adenosine triphosphate‐conducting mitochondrial outer membrane voltage‐dependent anion channel‐1 on the plasma membrane leading to adenosine triphosphate depletion. The interaction between reactive oxygen species overproduction and voltage‐dependent anion channel‐1 induction is an interesting issue to be resolved.![]()
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Affiliation(s)
- Shimpei Fujimoto
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Nankoku, Japan
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5
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Wang LN, Jiang HW, Li JL, Li JY. Enhancement of Glucose Utilization by Loesenerine through AMPK Activation in Myotubes. Chem Pharm Bull (Tokyo) 2018; 66:885-886. [DOI: 10.1248/cpb.c18-00253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Luo-Na Wang
- School of Life Sciences, Nanchang University
| | - Hao-Wen Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences
| | | | - Jing-Ya Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences
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6
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Sirolimus induces depletion of intracellular calcium stores and mitochondrial dysfunction in pancreatic beta cells. Sci Rep 2017; 7:15823. [PMID: 29158477 PMCID: PMC5696524 DOI: 10.1038/s41598-017-15283-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/20/2017] [Indexed: 12/19/2022] Open
Abstract
Sirolimus (rapamycin) is an immunosuppressive drug used in transplantation. One of its major side effects is the increased risk of diabetes mellitus; however, the exact mechanisms underlying such association have not been elucidated. Here we show that sirolimus impairs glucose-stimulated insulin secretion both in human and murine pancreatic islets and in clonal β cells in a dose- and time-dependent manner. Importantly, we demonstrate that sirolimus markedly depletes calcium (Ca2+) content in the endoplasmic reticulum and significantly decreases glucose-stimulated mitochondrial Ca2+ uptake. Crucially, the reduced mitochondrial Ca2+ uptake is mirrored by a significant impairment in mitochondrial respiration. Taken together, our findings indicate that sirolimus causes depletion of intracellular Ca2+ stores and alters mitochondrial fitness, eventually leading to decreased insulin release. Our results provide a novel molecular mechanism underlying the increased incidence of diabetes mellitus in patients treated with this drug.
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ATP synthase β-subunit abnormality in pancreas islets of rats with polycystic ovary syndrome and type 2 diabetes mellitus. ACTA ACUST UNITED AC 2017; 37:210-216. [PMID: 28397049 DOI: 10.1007/s11596-017-1717-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/06/2017] [Indexed: 10/18/2022]
Abstract
This study investigated the abnormal expression of ATP synthase β-subunit (ATPsyn-β) in pancreas islets of rat model of polycystic ovary syndrome (PCOS) with type 2 diabetes mellitus (T2DM), and the secretion function changes after up-regulation of ATP5b. Sixty female SD rats were divided into three groups randomly and equally. The rat model of PCOS with T2DM was established by free access to the high-carbohydrate/high-fat diet, subcutaneous injections of DHEA, and a single injection of streptozotocin. The pancreas was removed for the detection of the ATPsyn-β expression by immunohistochemical staining, Western blotting and reverse transcription-PCR (RT-PCR). The pancreas islets of the rats were cultured, isolated with collagenase V and purified by gradient centrifugation, and the insulin secretion after treatment with different glucose concentrations was tested. Lentivirus ATP5b was successfully constructed with the vector of GV208 and transfected into the pancreas islets for the over-expression of ATPsyn-β. The insulin secretion and intracellular ATP content were determined after transfection of the PCOS-T2DM pancreas islets with Lenti-ATP5b. The results showed that the expression of ATPsyn-β protein and mRNA was significantly decreased in the pancreas of PCOS-T2DM rats. The ATP content in the pancreas islets was greatly increased and the insulin secretion was improved after the up-regulation of ATPsyn-β in the pancreas islets transfected with lenti-ATP5b. These results indicated that for PCOS, the ATPsyn-β might be one of the key factors for the attack of T2DM.
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Altuntas S, D'Eletto M, Rossin F, Hidalgo LD, Farrace MG, Falasca L, Piredda L, Cocco S, Mastroberardino PG, Piacentini M, Campanella M. Type 2 Transglutaminase, mitochondria and Huntington's disease: menage a trois. Mitochondrion 2014; 19 Pt A:97-104. [PMID: 25262960 DOI: 10.1016/j.mito.2014.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 01/07/2023]
Abstract
Mitochondria produce the bulk of cellular energy and work as decisional "hubs" for cellular responses by integrating different input signals. The determinant in the physiopathology of mammals, they attract major attention, nowadays, for their contribution to brain degeneration. How they can withstand or succumb to insults leading to neuronal death is an object of great attention increasing the need for a better understanding of the interplay between inner and outer mitochondrial pathways residing in the cytosol. Of the latter, those dictating protein metabolism and therefore influencing the quality function and control of the organelle are of our most immediate interest and here we describe the Transglutaminase type 2 (TG2) contribution to mitochondrial function, dysfunction and neurodegeneration. Besides reviewing the latest evidences we share also the novel ones on the IF1 pathway depicting a molecular conduit governing mitochondrial turnover and homeostasis relevant to envisaging preventive and therapeutic strategies to respectively predict and counteract deficiencies associated with deregulated mitochondrial function in neuropathology.
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Affiliation(s)
- Sara Altuntas
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy
| | - Manuela D'Eletto
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy
| | - Federica Rossin
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy
| | - Laura Diaz Hidalgo
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy
| | | | - Laura Falasca
- National Institute for Infectious Diseases I.R.C.C.S. 'L. Spallanzani', Rome 00149, Italy
| | - Lucia Piredda
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy
| | - Stefania Cocco
- European Brain Research Institute (EBRI), Rita Levi-Montalcini Foundation, Rome 00143, Italy
| | | | - Mauro Piacentini
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy; National Institute for Infectious Diseases I.R.C.C.S. 'L. Spallanzani', Rome 00149, Italy.
| | - Michelangelo Campanella
- Department of Biology, University of Rome 'Tor Vergata', Rome 00133, Italy; European Brain Research Institute (EBRI), Rita Levi-Montalcini Foundation, Rome 00143, Italy; Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, UCL Consortium for Mitochondrial Research (CfMR), London, NW1 0TU, UK.
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9
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Funakoshi S, Fujimoto S, Hamasaki A, Fujiwara H, Fujita Y, Ikeda K, Takahara S, Seino Y, Inagaki N. Analysis of factors influencing postprandial C-peptide levels in Japanese patients with type 2 diabetes: Comparison with C-peptide levels after glucagon load. J Diabetes Investig 2014; 2:429-34. [PMID: 24843526 PMCID: PMC4014901 DOI: 10.1111/j.2040-1124.2011.00126.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Aims/Introduction: Postprandial serum C‐peptide levels are readily determined in clinical practice and have a good correlation with serum C‐peptide levels after glucagon load; the measurement is often used as an index of endogenous insulin secretion. However, the factors affecting postprandial serum C‐peptide levels remain to be evaluated. Materials and Methods: To investigate the clinical factors affecting postprandial serum C‐peptide, 2‐h postprandial C‐peptide levels after breakfast (PPCPR) were analyzed retrospectively for comparison with glucagon‐stimulated C‐peptide (CPR‐6min) levels measured during hospital admission in 273 Japanese patients with type 2 diabetes. Results: Multiple regression analysis showed that years from diagnosis, body mass index (BMI) and HbA1c were the major independent variables predicting PPCPR (R2 = 0.315). HbA1c was a major factor predicting PPCPR, but did not predict CPR‐6min. In addition, HbA1c was negatively correlated with PPCPR (r = −0.410, P < 0.0001) and PPCPR/CPR‐6min (r = −0.313, P < 0.0001). Conclusions: PPCPR was correlated with common factors predicting CPR, including years from diagnosis and BMI, but also was negatively correlated with HbA1c, a unique factor. These results show that chronic elevation of the glucose level might impair endogenous insulin secretion after meal load, but might have little effect on endogenous insulin secretion after glucagon load. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00126.x, 2011)
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Affiliation(s)
- Shogo Funakoshi
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Shimpei Fujimoto
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Akihiro Hamasaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Hideya Fujiwara
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Yoshihito Fujita
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Kaori Ikeda
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | - Shiho Takahara
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
| | | | - Nobuya Inagaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto
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10
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Abstract
Recently, Leahy et al. issued a “consensus statement” in regard to targeting β‐cell function in therapy for type 2 diabetes that recommends continued multidisciplinary efforts to realign treatment of type 2 diabetes to preserve β‐cell function by early intervention. This might be applicable not only for obese type 2 diabetes in Europe and America, but also for lean type 2 diabetes in Asia. To establish evidence, development of non‐invasive measurements of β‐cell mass for longitudinal observation during long duration of diabetes is critical. In addition, studies that clarify the development of β‐cell dysfunction with regard to both mass reduction and functional impairment are required for the development of novel strategies to preserve β‐cell function by treatment of type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00117.x, 2011)
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Affiliation(s)
- Shimpei Fujimoto
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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11
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Jin HS, Kim J, Lee SJ, Kim K, Go MJ, Lee JY, Lee HJ, Song J, Jeon BT, Roh GS, Kim SJ, Kim BY, Hong KW, Yoo YH, Oh B, Kang Y, Jeong SY. The PARK2 gene is involved in the maintenance of pancreatic β-cell functions related to insulin production and secretion. Mol Cell Endocrinol 2014; 382:178-189. [PMID: 24096089 DOI: 10.1016/j.mce.2013.09.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 09/18/2013] [Accepted: 09/24/2013] [Indexed: 01/18/2023]
Abstract
Several association studies have implicated the PARK2 gene that encodes parkin--the key molecule orchestrating the mitochondrial quality control system--as a candidate susceptibility gene for diabetes. A total of 7551 unrelated Korean KARE cohort subjects were analyzed to investigate the association between the PARK2 single nucleotide polymorphism (SNP) and quantitative glycemic traits. Two SNPs, rs10455889 and rs9365294, were significantly associated with fasting plasma glucose level (p=∼1.2×10(-4)) and insulin secretion indices (p=∼7.4×10(-5)) in male KARE subjects. Parkin was expressed predominantly in the rat pancreatic islets. Downregulation of the Park2 gene in rat INS-1 β-cells resulted in a significant decrease in the glucose-stimulated insulin secretion, intracellular insulin gene expression, and intracellular ATP level. The Park2-depleted β-cells also exhibited increased mitochondrial fragmentation and ROS production and decreased mitochondrial membrane potential. Both population-based statistical evaluation and experimental evidence demonstrated a fundamental role of the PARK2 gene in the maintenance of β-cell function.
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Affiliation(s)
- Hyun-Seok Jin
- Department of Medical Genetics, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jeonghyun Kim
- Department of Medical Genetics, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Soo-Jin Lee
- Institute for Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Kyunga Kim
- Department of Statistics, Sookmyung Women's University, Seoul, Republic of Korea
| | - Min Jin Go
- Centre for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Jong-Young Lee
- Centre for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Hye-Ja Lee
- Division of Metabolic Diseases, Centre for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, Republic of Korea
| | - Jihyun Song
- Division of Metabolic Diseases, Centre for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, Republic of Korea
| | - Byeong Tak Jeon
- Department of Anatomy and Neurobiology, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - Gu Seob Roh
- Department of Anatomy and Neurobiology, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - Sung-Jun Kim
- Drug Evaluation Centre, CJ CheilJedang Corporation, Icheon, Republic of Korea
| | - Bo-Young Kim
- Department of Medical Genetics, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Kyung-Won Hong
- Division of Epidemiology and Health Index, Centre for Genome Science, Korea Centres for Disease Control & Prevention, Chungcheongbuk-do, Republic of Korea
| | - Young-Hyun Yoo
- Department of Anatomy and Cell Biology and Mitochondria Hub Regulation Centre, College of Medicine, Dong-A University, Republic of Korea
| | - Beomseok Oh
- Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Yup Kang
- Institute for Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea.
| | - Seon-Yong Jeong
- Department of Medical Genetics, Ajou University School of Medicine, Suwon, Republic of Korea.
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12
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Ghaly H, Jörns A, Rustenbeck I. Effect of fluoroquinolones on mitochondrial function in pancreatic beta cells. Eur J Pharm Sci 2013; 52:206-14. [PMID: 24284031 DOI: 10.1016/j.ejps.2013.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 11/04/2013] [Accepted: 11/12/2013] [Indexed: 11/19/2022]
Abstract
Hyper- and hypoglycaemias are known side effects of fluoroquinolone antibiotics, resulting in a number of fatalities. Fluoroquinolone-induced hypoglycaemias are due to stimulated insulin release by the inhibition of the KATP channel activity of the beta cell. Recently, it was found that fluoroquinolones were much less effective on metabolically intact beta cells than on open cell preparations. Thus the intracellular effects of gatifloxacin, moxifloxacin and ciprofloxacin were investigated by measuring NAD(P)H- and FAD-autofluorescence, the mitochondrial membrane potential, and the adenine nucleotide content of isolated pancreatic islets and beta cells. 100 μM of moxifloxacin abolished the NAD(P)H increase elicited by 20mM glucose, while gatifloxacin diminished it and ciprofloxacin had no significant effect. This pattern was also seen with islets from SUR1 Ko mice, which have no functional KATP channels. Moxifloxacin also diminished the glucose-induced decrease of FAD-fluorescence, which reflects the intramitochondrial production of reducing equivalents. Moxifloxacin, but not ciprofloxacin or gatifloxacin significantly reduced the effect of 20mM glucose on the ATP/ADP ratio. The mitochondrial hyperpolarization caused by 20mM glucose was partially antagonized by moxifloxacin, but not by ciprofloxacin or gatifloxacin. Ultrastructural analyses after 20 h tissue culture showed that all three compounds (at 10 and 100 μM) diminished the number of insulin secretory granules and that gatifloxacin and ciprofloxacin, but not moxifloxacin induced fission/fusion configurations of the beta cell mitochondria. In conclusion, fluoroquinolones affect the function of the mitochondria in pancreatic beta cells which may diminish the insulinotropic effect of KATP channel closure and contribute to the hyperglycaemic episodes.
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Affiliation(s)
- Hany Ghaly
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Anne Jörns
- Institute of Clinical Biochemistry, Hannover Medical School, 30623 Hannover, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany.
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13
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Shizukaol D isolated from Chloranthus japonicas inhibits AMPK-dependent lipid content in hepatic cells by inducing mitochondrial dysfunction. PLoS One 2013; 8:e73527. [PMID: 23967345 PMCID: PMC3743771 DOI: 10.1371/journal.pone.0073527] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/22/2013] [Indexed: 11/19/2022] Open
Abstract
This study is the first to demonstrate that shizukaol D, a natural compound isolated from Chloranthusjaponicus, can activate AMP- activated protein kinase (AMPK), a key sensor and regulator of intracellular energy metabolism, leading to a decrease in triglyceride and cholesterol levels in HepG2 cells. Furthermore, we found that shizukaol D induces mitochondrial dysfunction by depolarizing the mitochondrial membrane and suppressing energy production, which may result in AMPK activation. Our results provide a possible link between mitochondrial dysfunction and AMPK activation and suggest that shizukaol D might be used to treat metabolic syndrome.
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14
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Sasaki M, Fujimoto S, Sato Y, Nishi Y, Mukai E, Yamano G, Sato H, Tahara Y, Ogura K, Nagashima K, Inagaki N. Reduction of reactive oxygen species ameliorates metabolism-secretion coupling in islets of diabetic GK rats by suppressing lactate overproduction. Diabetes 2013; 62:1996-2003. [PMID: 23349483 PMCID: PMC3661648 DOI: 10.2337/db12-0903] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We previously demonstrated that impaired glucose-induced insulin secretion (IS) and ATP elevation in islets of Goto-Kakizaki (GK) rats, a nonobese model of diabetes, were significantly restored by 30-60-min suppression of endogenous reactive oxygen species (ROS) overproduction. In this study, we investigated the effect of a longer (12 h) suppression of ROS on metabolism-secretion coupling in β-cells by exposure to tempol, a superoxide (O2(-)) dismutase mimic, plus ebselen, a glutathione peroxidase mimic (TE treatment). In GK islets, both H2O2 and O2(-) were sufficiently reduced and glucose-induced IS and ATP elevation were improved by TE treatment. Glucose oxidation, an indicator of Krebs cycle velocity, also was improved by TE treatment at high glucose, whereas glucokinase activity, which determines glycolytic velocity, was not affected. Lactate production was markedly increased in GK islets, and TE treatment reduced lactate production and protein expression of lactate dehydrogenase and hypoxia-inducible factor 1α (HIF1α). These results indicate that the Warburg-like effect, which is characteristic of aerobic metabolism in cancer cells by which lactate is overproduced with reduced linking to mitochondria metabolism, plays an important role in impaired metabolism-secretion coupling in diabetic β-cells and suggest that ROS reduction can improve mitochondrial metabolism by suppressing lactate overproduction through the inhibition of HIF1α stabilization.
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Affiliation(s)
- Mayumi Sasaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shimpei Fujimoto
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Nankoku, Japan
| | - Yuichi Sato
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuichi Nishi
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Nankoku, Japan
| | - Eri Mukai
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Gen Yamano
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroki Sato
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yumiko Tahara
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kasane Ogura
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kazuaki Nagashima
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Corresponding author: Nobuya Inagaki,
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15
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Ma Z, Wirström T, Borg LH, Larsson-Nyrén G, Hals I, Bondo-Hansen J, Grill V, Björklund A. Diabetes reduces β-cell mitochondria and induces distinct morphological abnormalities, which are reproducible by high glucose in vitro with attendant dysfunction. Islets 2012; 4:233-42. [PMID: 22854606 PMCID: PMC3442821 DOI: 10.4161/isl.20516] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We investigated the impact of a diabetic state with hyperglycemia on morphometry of β cell mitochondria and modifying influence of a K (+) -ATP channel opener and we related in vivo findings with glucose effects in vitro. For in vivo experiments islets from syngeneic rats were transplanted under the kidney capsule to neonatally streptozotocin-diabetic or non-diabetic recipients. Diabetic recipients received vehicle, or tifenazoxide (NN414), intragastrically for 9 weeks. Non-diabetic rats received vehicle. Transplants were excised 7 d after cessation of treatment (wash-out) and prepared for electron microscopy. Morphological parameters were measured from approx. 25,000 mitochondria. Rat islets were cultured in vitro for 2-3 weeks at 27 or 11 (control) mmol/l glucose. Transplants to diabetic rats displayed decreased numbers of mitochondria (-31%, p < 0.05), increased mitochondrial volume and increased mitochondrial outer surface area, p < 0.001. Diabetes increased variability in mitochondrial size with frequent appearance of mega-mitochondria. Tifenazoxide partly normalized diabetes-induced effects, and mega-mitochondria disappeared. Long-term culture of islets at 27 mmol/l glucose reproduced the in vivo morphological abnormalities. High-glucose culture was also associated with reduced ATP and ADP contents, reduced oxygen consumption, reduced signaling by MitoTracker Red and reduction of mitochondrial proteins (complexes I-IV), OPA 1 and glucose-induced insulin release. We conclude that (1) a long-term diabetic state leads to a reduced number of mitochondria and to distinct morphological abnormalities which are replicated by high glucose in vitro; (2) the morphological abnormalities are coupled to dysfunction; (3) K (+) -ATP channel openers may have potential to partly reverse glucose-induced effects.
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MESH Headings
- Animals
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cyclic S-Oxides/pharmacology
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Female
- Hyperglycemia/metabolism
- Hyperglycemia/pathology
- Hypoglycemic Agents/pharmacology
- Islets of Langerhans/metabolism
- Islets of Langerhans/pathology
- Male
- Microscopy, Electron
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondria/ultrastructure
- Rats
- Rats, Inbred WF
- Rats, Sprague-Dawley
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Affiliation(s)
- Zuheng Ma
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm, Sweden
| | - Tina Wirström
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm, Sweden
| | - L.A. Håkan Borg
- Department of Medical Cell Biology; University of Uppsala; Uppsala, Sweden
| | - Gerd Larsson-Nyrén
- Department of Integrative Medical Biology; Section for Histology and Cell Biology; Umeå University; Umeå, Sweden
| | - Ingrid Hals
- Institute of Cancer Research and Molecular Medicine; The Medical Faculty; Norwegian University of Science and Technology; Trondheim, Norway
| | | | - Valdemar Grill
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm, Sweden
- Institute of Cancer Research and Molecular Medicine; The Medical Faculty; Norwegian University of Science and Technology; Trondheim, Norway
- Department of Endocrinology; St. Olav’s University Hospital; Trondheim, Norway
| | - Anneli Björklund
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm, Sweden
- Correspondence to: Anneli Björklund,
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16
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Cambier L, Rassam P, Chabi B, Mezghenna K, Gross R, Eveno E, Auffray C, Wrutniak-Cabello C, Lajoix AD, Pomiès P. M19 modulates skeletal muscle differentiation and insulin secretion in pancreatic β-cells through modulation of respiratory chain activity. PLoS One 2012; 7:e31815. [PMID: 22363741 PMCID: PMC3282743 DOI: 10.1371/journal.pone.0031815] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 01/13/2012] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial dysfunction due to nuclear or mitochondrial DNA alterations contributes to multiple diseases such as metabolic myopathies, neurodegenerative disorders, diabetes and cancer. Nevertheless, to date, only half of the estimated 1,500 mitochondrial proteins has been identified, and the function of most of these proteins remains to be determined. Here, we characterize the function of M19, a novel mitochondrial nucleoid protein, in muscle and pancreatic β-cells. We have identified a 13-long amino acid sequence located at the N-terminus of M19 that targets the protein to mitochondria. Furthermore, using RNA interference and over-expression strategies, we demonstrate that M19 modulates mitochondrial oxygen consumption and ATP production, and could therefore regulate the respiratory chain activity. In an effort to determine whether M19 could play a role in the regulation of various cell activities, we show that this nucleoid protein, probably through its modulation of mitochondrial ATP production, acts on late muscle differentiation in myogenic C2C12 cells, and plays a permissive role on insulin secretion under basal glucose conditions in INS-1 pancreatic β-cells. Our results are therefore establishing a functional link between a mitochondrial nucleoid protein and the modulation of respiratory chain activities leading to the regulation of major cellular processes such as myogenesis and insulin secretion.
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Affiliation(s)
- Linda Cambier
- CNRS UMR5237, Centre de Recherche en Biochimie Macromoléculaire, Montpellier, France
- Université Montpellier 1, Montpellier, France
- Université Montpellier 2, Montpellier, France
| | - Patrice Rassam
- CNRS UMR5237, Centre de Recherche en Biochimie Macromoléculaire, Montpellier, France
- Université Montpellier 1, Montpellier, France
- Université Montpellier 2, Montpellier, France
| | - Béatrice Chabi
- INRA UMR866, Dynamique Musculaire et Métabolisme, Montpellier, France
- Université Montpellier 1, Montpellier, France
- Université Montpellier 2, Montpellier, France
| | - Karima Mezghenna
- CNRS UMR5232, Centre for Pharmacology and Innovation in Diabetes, Montpellier, France
- Université Montpellier 1, Montpellier, France
| | - René Gross
- CNRS UMR5232, Centre for Pharmacology and Innovation in Diabetes, Montpellier, France
- Université Montpellier 1, Montpellier, France
| | - Eric Eveno
- Genexpress, Functional Genomics and Systems Biology for Health, CNRS Institute of Biological Sciences, Villejuif, France
| | - Charles Auffray
- Genexpress, Functional Genomics and Systems Biology for Health, CNRS Institute of Biological Sciences, Villejuif, France
| | - Chantal Wrutniak-Cabello
- INRA UMR866, Dynamique Musculaire et Métabolisme, Montpellier, France
- Université Montpellier 1, Montpellier, France
- Université Montpellier 2, Montpellier, France
| | - Anne-Dominique Lajoix
- CNRS UMR5232, Centre for Pharmacology and Innovation in Diabetes, Montpellier, France
- Université Montpellier 1, Montpellier, France
| | - Pascal Pomiès
- CNRS UMR5237, Centre de Recherche en Biochimie Macromoléculaire, Montpellier, France
- Université Montpellier 1, Montpellier, France
- Université Montpellier 2, Montpellier, France
- INSERM U1046, Physiologie et Médecine Expérimentale du Coeur et des Muscles, Montpellier, France
- * E-mail:
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17
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Fridlyand LE, Phillipson LH. Mechanisms of glucose sensing in the pancreatic β-cell: A computational systems-based analysis. Islets 2011; 3:224-30. [PMID: 21814042 PMCID: PMC3219158 DOI: 10.4161/isl.3.5.16409] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pancreatic β-cells respond to rising blood glucose by increasing oxidative metabolism, leading to an increased ATP/ADP ratio in the cytoplasm with a subsequent influx of calcium and the eventual secretion of insulin. The mechanisms of glucose sensing in the pancreatic β-cell involve the coupling of cytoplasmic and mitochondrial processes. Our analysis, based on mathematical models of data from multiple sources has implications for β-cell function and the treatment of type 2 diabetes (Fridlyand and Philipson, 2010). This β-cell glucose response model correctly predicts changes in the ATP/ADP ratio, cytoplasmic and mitochondrial calcium levels, and other metabolic parameters in response to alterations in substrate delivery at steady-state and during cytoplasmic calcium oscillations. Here we consider how peculiarities of β-cell pathways that result in dysfunction can be a consequence of specific mechanisms of glucose sensitivity, using our computational systems-based analysis. We found that the mitochondrial membrane potential must be relatively low in β-cells compared with other cell types to permit precise mitochondrial regulation of the cytoplasmic ATP/ADP ratio. This key difference may follow from a relative reduction in cellular respiratory activity. Our analysis additionally demonstrates how activity of lactate dehydrogenase, uncoupling proteins, and the redox shuttles all working in concert can regulate β-cell function. We further show that a decreased mitochondrial membrane potential may lead to a low rate of production of reactive oxygen species in β-cells under physiological conditions. This computational systems analysis aids in providing a more complete understanding of the complex process of β-cell glucose sensing.
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18
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Fujimoto S, Mukai E, Inagaki N. Role of endogenous ROS production in impaired metabolism-secretion coupling of diabetic pancreatic β cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:304-10. [PMID: 21839765 DOI: 10.1016/j.pbiomolbio.2011.07.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 07/30/2011] [Accepted: 07/31/2011] [Indexed: 12/25/2022]
Abstract
One of the characteristics of type 2 diabetes is that the insulin secretory response of β cells is selectively impaired to glucose. In the Goto-Kakizaki (GK) rat, a genetic model of type 2 diabetes mellitus, glucose-induced insulin secretion is selectively impaired due to deficient ATP production derived from impaired glucose metabolism. In addition, islets in GK rat and human type 2 diabetes are oxidatively stressed. In this issue, role of endogenous reactive oxygen species (ROS) production in impaired metabolism-secretion coupling of diabetic pancreatic β cells is reviewed. In β cells, ROS is endogenously produced by activation of Src, a non-receptor tyrosine kinase. Src inhibitors restore the impaired insulin release and impaired ATP elevation by reduction in ROS production in diabetic islets. Src is endogenously activated in diabetic islets, since the level of Src pY416 in GK islets is higher than that in control islets. In addition, exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, decreases Src pY416 and glucose-induced ROS production and ameliorates impaired ATP production dependently on Epac in GK islets. These results indicate that GLP-1 signaling regulates endogenous ROS production due to Src activation and that incretin has unique therapeutic effects on impaired glucose metabolism in diabetic β cells.
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Affiliation(s)
- Shimpei Fujimoto
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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19
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Zhang Z, Wakabayashi N, Wakabayashi J, Tamura Y, Song WJ, Sereda S, Clerc P, Polster BM, Aja SM, Pletnikov MV, Kensler TW, Shirihai OS, Iijima M, Hussain MA, Sesaki H. The dynamin-related GTPase Opa1 is required for glucose-stimulated ATP production in pancreatic beta cells. Mol Biol Cell 2011; 22:2235-45. [PMID: 21551073 PMCID: PMC3128526 DOI: 10.1091/mbc.e10-12-0933] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The physiological function of Opa1, a dynamin-related GTPase required for mitochondrial fusion, is described in glucose-stimulated ATP production in pancreatic beta cells. Previous studies using in vitro cell culture systems have shown the role of the dynamin-related GTPase Opa1 in apoptosis prevention and mitochondrial DNA (mtDNA) maintenance. However, it remains to be tested whether these functions of Opa1 are physiologically important in vivo in mammals. Here, using the Cre-loxP system, we deleted mouse Opa1 in pancreatic beta cells, in which glucose-stimulated ATP production in mitochondria plays a key role in insulin secretion. Beta cells lacking Opa1 maintained normal copy numbers of mtDNA; however, the amount and activity of electron transport chain complex IV were significantly decreased, leading to impaired glucose-stimulated ATP production and insulin secretion. In addition, in Opa1-null beta cells, cell proliferation was impaired, whereas apoptosis was not promoted. Consequently, mice lacking Opa1 in beta cells develop hyperglycemia. The data suggest that the function of Opa1 in the maintenance of the electron transport chain is physiologically relevant in beta cells.
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Affiliation(s)
- Zhongyan Zhang
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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20
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Lidocaine depolarizes the mitochondrial membrane potential by intracellular alkalization in rat dorsal root ganglion neurons. J Anesth 2011; 25:229-39. [PMID: 21212988 DOI: 10.1007/s00540-010-1079-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE The mitochondrial membrane potential (ΔΨm) is an important factor for apoptosis, and it is produced by the proton electrochemical gradient (ΔµH(+)). Therefore, the intracellular proton concentration (pH(in)) is an important factor for modifying the ΔΨm. However, the effects of lidocaine on pH(in) are unclear. To investigate mitochondrial responses to lidocaine, therefore, we simultaneously measured pH(in) with ΔΨm, flavin adenine dinucleotide (FAD), and reduced form of nicotinamide adenine dinucleotide (NADH) fluorescence, and calculated the FAD/NADH ratio (redox ratio), the superoxide production in mitochondria. METHODS Morphological change and early apoptosis were observed by annexin-V FITC staining under fluorescent microscope. The ratiometric fluorescent probe JC-1 and HPTS were used for the simultaneous measurements of ΔΨm with pH(in) in rat dorsal root ganglion (DRG) neurons. FAD and NADH autofluorescence were simultaneously measured, and the FAD/NADH fluorescence ratio (redox ratio) was calculated. The superoxide was measured by mitosox-red fluorescent probe for mitochondrial superoxide. Lidocaine was evaluated at 1, 5, and 10 mM. RESULTS Morphological change and early apoptosis were observed after 10 mM lidocaine administration. Lidocaine depolarized ΔΨm with increased pH(in) in a dose-dependent manner. In low-pH saline (pH 6), in the presence of both the weak acids (acetate and propionate), lidocaine failed to depolarize ΔΨm and increase pH(in). On the other hand, lidocaine decreased the redox ratio in the cell and increased the levels of superoxide in a dose-dependent manner. CONCLUSION These results demonstrated that lidocaine depolarizes ΔΨm by intracellular alkalization. These results may indicate one of the mechanisms responsible for lidocaine-induced neurotoxicity.
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21
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Kruglov AG, Andersson MA, Mikkola R, Roivainen M, Kredics L, Saris NEL, Salkinoja-Salonen MS. Novel mycotoxin from Acremonium exuviarum is a powerful inhibitor of the mitochondrial respiratory chain complex III. Chem Res Toxicol 2010; 22:565-73. [PMID: 19193189 DOI: 10.1021/tx800317z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A novel mycotoxin named acrebol, consisting of two closely similar peptaibols (1726 and 1740 Da), was isolated from an indoor strain of the mitosporic ascomycete fungus Acremonium exuviarum. This paper describes the unique mitochondrial toxicity of acrebol, not earlier described for any peptaibol. Acrebol inhibited complex III of the respiratory chain of isolated rat liver mitochondria (1 mg of protein mL(-1)) with an IC(50) of approximately 80 ng mL(-1) (50 nM) after a short preincubation, and 350 ng mL(-1) caused immediate and complete inhibition. Acrebol thus is a complex III inhibitor almost as potent as antimycin A and myxothiazol but completely different in structure. Similarly to myxothiazol but in contrast to antimycin A, acrebol decreased the level of mitochondrial superoxide anion detectable by chemiluminescent probe 3,7-dihydro-2-methyl-6-(4-methoxyphenyl)imidazol[1,2-a]pyrazine-3-one. Unlike other peptaibols, acrebol in toxic concentrations did not increase the ionic and solute permeability of membranes of isolated rat liver mitochondria, did not induce disturbance of the ionic homeostasis or the osmotic balance of mitochondria, and did not release apoptogenic proteins like cytochrome c from the intermembrane space of mitochondria. In boar spermatozoa, acrebol inhibited the respiratory chain and caused ATP depletion by activation of the oligomycin-sensitive F(0)F(1)-ATPase, which resulted in the inhibition of the progressive movement. In mouse insulinoma MIN-6 cells, whose energy supply solely depends on oxidative phosphorylation, acrebol induced necrosis-like death. The pathophysiological relevance of these findings is discussed.
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Affiliation(s)
- Alexey G Kruglov
- Department of Applied Chemistry and Microbiology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
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22
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Fridlyand LE, Philipson LH. Glucose sensing in the pancreatic beta cell: a computational systems analysis. Theor Biol Med Model 2010; 7:15. [PMID: 20497556 PMCID: PMC2896931 DOI: 10.1186/1742-4682-7-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 05/24/2010] [Indexed: 12/29/2022] Open
Abstract
Background Pancreatic beta-cells respond to rising blood glucose by increasing oxidative metabolism, leading to an increased ATP/ADP ratio in the cytoplasm. This leads to a closure of KATP channels, depolarization of the plasma membrane, influx of calcium and the eventual secretion of insulin. Such mechanism suggests that beta-cell metabolism should have a functional regulation specific to secretion, as opposed to coupling to contraction. The goal of this work is to uncover contributions of the cytoplasmic and mitochondrial processes in this secretory coupling mechanism using mathematical modeling in a systems biology approach. Methods We describe a mathematical model of beta-cell sensitivity to glucose. The cytoplasmic part of the model includes equations describing glucokinase, glycolysis, pyruvate reduction, NADH and ATP production and consumption. The mitochondrial part begins with production of NADH, which is regulated by pyruvate dehydrogenase. NADH is used in the electron transport chain to establish a proton motive force, driving the F1F0 ATPase. Redox shuttles and mitochondrial Ca2+ handling were also modeled. Results The model correctly predicts changes in the ATP/ADP ratio, Ca2+ and other metabolic parameters in response to changes in substrate delivery at steady-state and during cytoplasmic Ca2+ oscillations. Our analysis of the model simulations suggests that the mitochondrial membrane potential should be relatively lower in beta cells compared with other cell types to permit precise mitochondrial regulation of the cytoplasmic ATP/ADP ratio. This key difference may follow from a relative reduction in respiratory activity. The model demonstrates how activity of lactate dehydrogenase, uncoupling proteins and the redox shuttles can regulate beta-cell function in concert; that independent oscillations of cytoplasmic Ca2+ can lead to slow coupled metabolic oscillations; and that the relatively low production rate of reactive oxygen species in beta-cells under physiological conditions is a consequence of the relatively decreased mitochondrial membrane potential. Conclusion This comprehensive model predicts a special role for mitochondrial control mechanisms in insulin secretion and ROS generation in the beta cell. The model can be used for testing and generating control hypotheses and will help to provide a more complete understanding of beta-cell glucose-sensing central to the physiology and pathology of pancreatic β-cells.
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Affiliation(s)
- Leonid E Fridlyand
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA.
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23
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Abstract
There are many instances in life when the environment plays a critical role in the health outcomes of an individual, yet none more so than those experienced in fetal and neonatal life. One of the most detrimental environmental problems encountered during this critical growth period are changes in nutrition to the growing fetus and newborn. Disturbances in the supply of nutrients and oxygen to the fetus can not only lead to adverse fetal growth patterns, but they have also been associated with the development of features of metabolic syndrome in adult life. This fetal response has been termed developmental programming or the developmental origins of health and disease. The present review focuses on the epidemiological studies that identified this association and the importance that animal models have played in studying this concept. We also address the potential mechanisms that may underpin the developmental programming of future disease. It also highlights (i) how developmental plasticity, although beneficial for short-term survival, can subsequently programme glucose intolerance and insulin resistance in adult life by eliciting changes in key organ structures and the epigenome, and (ii) how aberrant mitochondrial function can potentially lead to the development of Type 2 diabetes and other features of metabolic syndrome.
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Affiliation(s)
- Matthew J Warner
- Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, UK
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24
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Qiu BY, Turner N, Li YY, Gu M, Huang MW, Wu F, Pang T, Nan FJ, Ye JM, Li JY, Li J. High-throughput assay for modulators of mitochondrial membrane potential identifies a novel compound with beneficial effects on db/db mice. Diabetes 2010; 59:256-65. [PMID: 19833880 PMCID: PMC2797930 DOI: 10.2337/db09-0223] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Recently, several drugs have been shown to exert beneficial effects for metabolic syndrome through mild regulation of mitochondrial function. Hence, we explored a strategy of targeting mitochondrial function to improve glucose and lipid metabolism. RESEARCH DESIGN AND METHODS Mitochondrial membrane potential (Deltapsim) is a marker of mitochondrial function; therefore, we set up a high-throughput screening assay of Deltapsim in L6 myotubes. The effects of a selected lead compound were investigated in vitro and in vivo in relation to metabolic syndrome. RESULTS A novel small-molecule compound, C1, was identified through this high-throughput screening. C1 depolarized Deltapsim in L6 myotubes without cytotoxicity and led to increased cellular AMP-to-ATP ratio, activation of AMP-activated protein kinase (AMPK), and enhanced glucose uptake. It also stimulated the AMPK pathway in HepG2 cells, leading to decreased lipid content. Intriguingly, C1 inhibited respiration in L6 myotubes but did not affect respiration in isolated muscle mitochondria, suggesting that it may depolarize Deltapsim indirectly by affecting the supply of electron donors. Acute administration of C1 in C57BL/6J mice markedly increased fat oxidation and the phosphorylation of AMPK and acetyl-CoA carboxylase in the liver. In diabetic db/db mice, chronic administration of C1 significantly reduced hyperglycemia, plasma fatty acids, glucose intolerance, and the mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase in the liver. CONCLUSIONS Our results demonstrate a novel small molecule that mildly depolarizes Deltapsim and is able to improve glucose and lipid metabolism to exert beneficial effects for metabolic syndrome. These findings suggest that compounds regulating mitochondrial function may have therapeutic potential for type 2 diabetes.
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Affiliation(s)
- Bei-Ying Qiu
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Nigel Turner
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia
- St. Vincent's Hospital Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Yuan-Yuan Li
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Min Gu
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | | | - Fang Wu
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Tao Pang
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Fa-Jun Nan
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ji-Ming Ye
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jing-Ya Li
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Corresponding authors: Jia Li, , and Jing-Ya Li,
| | - Jia Li
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Corresponding authors: Jia Li, , and Jing-Ya Li,
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25
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Abstract
OBJECTIVE The Vhlh gene codes for the von Hippel-Lindau protein (VHL), a tumor suppressor that is a key player in the cellular response to oxygen sensing. In humans, a germline mutation in the VHL gene leads to the von Hippel-Lindau disease, a familial syndrome characterized by benign and malignant tumors of the kidney, central nervous system, and pancreas. RESEARCH DESIGN AND METHODS We use Cre-lox recombination to eliminate Vhlh in adult mouse pancreatic beta-cells. Morphology of mutant islets is assessed by immunofluorescence analysis. To determine the functional state of Vhlh(-/-) islets, insulin secretion is measured in vivo and in vitro, and quantitative PCR is used to identify changes in gene expression. RESULTS Loss of VHL in beta-cells leads to a severe glucose-intolerant phenotype in adult animals. Although VHL is not required for beta-cell specification and development, it is critical for beta-cell function. Insulin production is normal in beta-cells lacking VHL; however, insulin secretion in the presence of high concentrations of glucose is impaired. Furthermore, the loss of VHL leads to dysregulation of glycolytic enzymes, pointing to a perturbation of the intracellular energy homeostasis. CONCLUSIONS We show that loss of VHL in beta-cells leads to defects in glucose homeostasis, indicating an important and previously unappreciated role for VHL in beta-cell function. We believe that the beta-cell-specific Vhlh-deficient mice might be a useful tool as a "genetic hypoxia" model, to unravel the possible link between hypoxia signaling and impairment of beta-cell function.
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Affiliation(s)
- Sapna Puri
- Diabetes Center, Department of Medicine, University of California, San Francisco, California, USA
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26
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Stoppiglia LF, Rezende LF, Cappelli APG, Ferreira F, Boschero AC. Altered NAD(P)H production in neonatal rat islets resistant to H2O2. Life Sci 2008; 83:709-16. [PMID: 18930068 DOI: 10.1016/j.lfs.2008.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 08/12/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
Abstract
AIMS We determined the involvement of NAD(P)H generation ability on the resistance of pancreatic islets B-cells to oxidative stress caused by culture exposition to H2O2. MAIN METHODS We cultured isolated neonatal Wistar rat islets for four days in medium containing 5.6 or 20 mM glucose, with or without H2O2 (200 microM), and analyzed several parameters associated with islet survival in different media. High glucose was used since it protects neonatal islets against the loss of GSIS. KEY FINDINGS While none of the culture conditions increased the rate of NAD(P)H content at 16.7 mM glucose, the islets resistant to H2O2 and those exposed to 20 mM glucose showed a greater use of the pentose phosphate pathway and increased ATP synthesis from glucose. SIGNIFICANCE Oxidative stress contributes to the loss of glucose-induced insulin secretion (GSIS) during the onset of diabetes mellitus. Although immature rat islets have reduced GSIS compared to mature islets, they adapt better to oxidative stress and are a good model for understanding the causes involved in the destruction or survival of islet cells. These data support the idea that GSIS and resistance against oxidative stress in immature islets rely on NADH shuttle activities, with little contribution of reduced equivalents from the tricarboxylic acid cycle (TCAC).
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Affiliation(s)
- Luiz F Stoppiglia
- Departamento de Química, Instituto de Ciências Exatas e da Terra, Universidade Federal de Cuiabá, MT, Brazil
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