1
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Zheng P, Ma W, Gu Y, Wu H, Bian Z, Liu N, Yang D, Chen X. High-fat diet causes mitochondrial damage and downregulation of mitofusin-2 and optic atrophy-1 in multiple organs. J Clin Biochem Nutr 2023; 73:61-76. [PMID: 37534099 PMCID: PMC10390808 DOI: 10.3164/jcbn.22-73] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 02/19/2023] [Indexed: 08/04/2023] Open
Abstract
High-fat consumption promotes the development of obesity, which is associated with various chronic illnesses. Mitochondria are the energy factories of eukaryotic cells, maintaining self-stability through a fine-tuned quality-control network. In the present study, we evaluated high-fat diet (HFD)-induced changes in mitochondrial ultrastructure and dynamics protein expression in multiple organs. C57BL/6J male mice were fed HFD or normal diet (ND) for 24 weeks. Compared with ND-fed mice, HFD-fed mice exhibited increased body weight, cardiomyocyte enlargement, pulmonary fibrosis, hepatic steatosis, renal and splenic structural abnormalities. The cellular apoptosis of the heart, liver, and kidney increased. Cellular lipid droplet deposition and mitochondrial deformations were observed. The proteins related to mitochondrial biogenesis (TFAM), fission (DRP1), autophagy (LC3 and LC3-II: LC3-I ratio), and mitophagy (PINK1) presented different changes in different organs. The mitochondrial fusion regulators mitofusin-2 (MFN2) and optic atrophy-1 (OPA1) were consistently downregulated in multiple organs, even the spleen. TOMM20 and ATP5A protein were enhanced in the heart, skeletal muscle, and spleen, and attenuated in the kidney. These results indicated that high-fat feeding caused pathological changes in multiple organs, accompanied by mitochondrial ultrastructural damage, and MFN2 and OPA1 downregulation. The mitochondrial fusion proteins may become promising targets and/or markers for treating metabolic disease.
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Affiliation(s)
- Peng Zheng
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Wenjing Ma
- Core Facility, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Yilu Gu
- Department of Pathology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Hengfang Wu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Zhiping Bian
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Nannan Liu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Di Yang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
- Core Facility, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
| | - Xiangjian Chen
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu, China
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2
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Chen TH, Koh KY, Lin KMC, Chou CK. Mitochondrial Dysfunction as an Underlying Cause of Skeletal Muscle Disorders. Int J Mol Sci 2022; 23:12926. [PMID: 36361713 PMCID: PMC9653750 DOI: 10.3390/ijms232112926] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/21/2022] [Accepted: 10/21/2022] [Indexed: 09/19/2023] Open
Abstract
Mitochondria are an important energy source in skeletal muscle. A main function of mitochondria is the generation of ATP for energy through oxidative phosphorylation (OXPHOS). Mitochondrial defects or abnormalities can lead to muscle disease or multisystem disease. Mitochondrial dysfunction can be caused by defective mitochondrial OXPHOS, mtDNA mutations, Ca2+ imbalances, mitochondrial-related proteins, mitochondrial chaperone proteins, and ultrastructural defects. In addition, an imbalance between mitochondrial fusion and fission, lysosomal dysfunction due to insufficient biosynthesis, and/or defects in mitophagy can result in mitochondrial damage. In this review, we explore the association between impaired mitochondrial function and skeletal muscle disorders. Furthermore, we emphasize the need for more research to determine the specific clinical benefits of mitochondrial therapy in the treatment of skeletal muscle disorders.
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Affiliation(s)
- Tsung-Hsien Chen
- Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan
| | - Kok-Yean Koh
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan
| | - Kurt Ming-Chao Lin
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 35053, Taiwan
| | - Chu-Kuang Chou
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan
- Obesity Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan
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3
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Abad-Jiménez Z, Vezza T, López-Domènech S, Fernández-Reyes M, Canet F, Morillas C, Gómez-Abril SÁ, Bañuls C, Víctor VM, Rocha M. Impact of Roux-en-Y Gastric Bypass on Mitochondrial Biogenesis and Dynamics in Leukocytes of Obese Women. Antioxidants (Basel) 2022; 11:antiox11071302. [PMID: 35883794 PMCID: PMC9312345 DOI: 10.3390/antiox11071302] [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: 05/16/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 02/05/2023] Open
Abstract
The chronic low-grade inflammation widely associated with obesity can lead to a prooxidant status that triggers mitochondrial dysfunction. To date, Roux-en-Y gastric bypass (RYGB) is considered the most effective strategy for obese patients. However, little is known about its molecular mechanisms. This interventional study aimed to investigate whether RYGB modulates oxidative stress, inflammation and mitochondrial dynamics in the leukocytes of 47 obese women at one year follow-up. We evaluated biochemical parameters and serum inflammatory cytokines -TNFα, IL6 and IL1β- to assess systemic status. Total superoxide production -dHe-, mitochondrial membrane potential -TMRM-, leucocyte protein expression of inflammation mediators -MCP1 and NF-kB-, antioxidant defence -GPX1-, mitochondrial regulation—PGC1α, TFAM, OXPHOS and MIEAP- and dynamics -MFN2, MNF1, OPA1, FIS1 and p-DRP1- were also determined. After RYGB, a significant reduction in superoxide and mitochondrial membrane potential was evident, while GPX1 content was significantly increased. Likewise, a marked upregulation of the transcription factors PGC1α and TFAM, complexes of the oxidative phosphorylation chain (I–V) and MIEAP and MFN1 was observed. We conclude that women undergoing RYGB benefit from an amelioration of their prooxidant and inflammatory status and an improvement in mitochondrial dynamics of their leukocytes, which is likely to have a positive effect on clinical outcome.
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Affiliation(s)
- Zaida Abad-Jiménez
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Teresa Vezza
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Sandra López-Domènech
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Meylin Fernández-Reyes
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Francisco Canet
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Carlos Morillas
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Segundo Ángel Gómez-Abril
- Department of General and Digestive System Surgery, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain;
- Department of Surgery, Faculty of Medicine and Dentistry, University of Valencia, Av. Blasco Ibáñez 13, 46010 Valencia, Spain
| | - Celia Bañuls
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
| | - Víctor M. Víctor
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
- CIBERehd-Department of Pharmacology, University of Valencia, Av. Blasco Ibáñez 13, 46010 Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, 46010 Valencia, Spain
- Correspondence: (V.M.V.); (M.R.); Tel.: +34-96-318-91-32 (M.R.)
| | - Milagros Rocha
- Department of Endocrinology and Nutrition, University Hospital Doctor Peset, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), 46017 Valencia, Spain; (Z.A.-J.); (T.V.); (S.L.-D.); (M.F.-R.); (F.C.); (C.M.); (C.B.)
- CIBERehd-Department of Pharmacology, University of Valencia, Av. Blasco Ibáñez 13, 46010 Valencia, Spain
- Correspondence: (V.M.V.); (M.R.); Tel.: +34-96-318-91-32 (M.R.)
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4
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Fealy CE, Grevendonk L, Hoeks J, Hesselink MKC. Skeletal muscle mitochondrial network dynamics in metabolic disorders and aging. Trends Mol Med 2021; 27:1033-1044. [PMID: 34417125 DOI: 10.1016/j.molmed.2021.07.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/13/2021] [Accepted: 07/26/2021] [Indexed: 01/05/2023]
Abstract
With global demographics trending towards an aging population, the numbers of individuals with an age-associated loss of independence is increasing. A key contributing factor is loss of skeletal muscle mitochondrial, metabolic, and contractile function. Recent advances in imaging technologies have demonstrated the importance of mitochondrial morphology and dynamics in the pathogenesis of disease. In this review, we examine the evidence for altered mitochondrial dynamics as a mechanism in age and obesity-associated loss of skeletal muscle function, with a particular focus on the available human data. We highlight some of the areas where more data are needed to identify the specific mechanisms connecting mitochondrial morphology and skeletal muscle dysfunction.
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Affiliation(s)
- Ciarán E Fealy
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands; Department of Physical Education and Sport Sciences, University of Limerick, Castletroy, Limerick, Ireland
| | - Lotte Grevendonk
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Joris Hoeks
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Matthijs K C Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
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5
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Castro-Sepulveda M, Fernández-Verdejo R, Tuñón-Suárez M, Morales-Zúñiga J, Troncoso M, Jannas-Vela S, Zbinden-Foncea H. Low abundance of Mfn2 protein correlates with reduced mitochondria-SR juxtaposition and mitochondrial cristae density in human men skeletal muscle: Examining organelle measurements from TEM images. FASEB J 2021; 35:e21553. [PMID: 33749943 DOI: 10.1096/fj.202002615rr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/24/2021] [Accepted: 03/08/2021] [Indexed: 12/29/2022]
Abstract
The role of mitofusin 2 (Mfn2) in the regulation of skeletal muscle (SM) mitochondria-sarcoplasmic (SR) juxtaposition, mitochondrial morphology, mitochondrial cristae density (MCD), and SM quality has not been studied in humans. In in vitro studies, whether Mfn2 increases or decreases mitochondria-SR juxtaposition remains controversial. Transmission electron microscopy (TEM) images are commonly used to measure the organelle juxtaposition, but the measurements are performed "by-hand," thus potentially leading to between-rater differences. The purposes of this study were to: (1) examine the repeatability and reproducibility of mitochondrial-SR juxtaposition measurement from TEM images of human SM between three raters with different experience and (2) compare the mitochondrial-SR juxtaposition, mitochondrial morphology, MCD (stereological-method), and SM quality (cross-sectional area [CSA] and the maximum voluntary contraction [MVC]) between subjects with high abundance (Mfn2-HA; n = 6) and low abundance (Mfn2-LA; n = 6) of Mfn2 protein. The mitochondria-SR juxtaposition had moderate repeatability and reproducibility, with the most experienced raters showing the best values. There were no differences between Mfn2-HA and Mfn2-LA groups in mitochondrial size, distance from mitochondria to SR, CSA, or MVC. Nevertheless, the Mfn2-LA group showed lower mitochondria-SR interaction, MCD, and VO2max . In conclusion, mitochondrial-SR juxtaposition measurement depends on the experience of the rater, and Mfn2 protein seems to play a role in the metabolic control of human men SM, by regulating the mitochondria-SR interaction.
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Affiliation(s)
- Mauricio Castro-Sepulveda
- Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile.,Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Fernández-Verdejo
- Carrera de Nutrición y Dietética, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mauro Tuñón-Suárez
- Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Jorge Morales-Zúñiga
- Laboratorio de Ciencias del Deporte, Clínica Sports Medicina Deportiva, Viña del Mar, Chile
| | - Mayarling Troncoso
- Faculty of Chemical and Pharmaceutical Science & Faculty of Medicine, Advanced Center for Chronic Diseases (ACCDiS), Universidad de Chile, Santiago, Chile
| | - Sebastian Jannas-Vela
- Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Hermann Zbinden-Foncea
- Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile.,Centro de Salud Deportiva, Clinica Santa Maria, Santiago, Chile
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6
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Abstract
Mounting evidence suggests a role for mitochondrial dysfunction in the pathogenesis of many diseases, including type 2 diabetes, aging, and ovarian failure. Because of the central role of mitochondria in energy production, heme biosynthesis, calcium buffering, steroidogenesis, and apoptosis signaling within cells, understanding the molecular mechanisms behind mitochondrial dysregulation and its potential implications in disease is critical. This review will take a journey through the past and summarize what is known about mitochondrial dysfunction in various disorders, focusing on metabolic alterations and reproductive abnormalities. Evidence is presented from studies in different human populations, and rodents with genetic manipulations of pathways known to affect mitochondrial function.
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Affiliation(s)
- Manasi Das
- VA San Diego Healthcare System, San Diego, California
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, California
| | - Consuelo Sauceda
- VA San Diego Healthcare System, San Diego, California
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, California
| | - Nicholas J G Webster
- VA San Diego Healthcare System, San Diego, California
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, California
- Moores Cancer Center, University of California, San Diego, La Jolla, California
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7
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Garcia BM, Machado TS, Carvalho KF, Nolasco P, Nociti RP, Del Collado M, Capo Bianco MJD, Grejo MP, Augusto Neto JD, Sugiyama FHC, Tostes K, Pandey AK, Gonçalves LM, Perecin F, Meirelles FV, Ferraz JBS, Vanzela EC, Boschero AC, Guimarães FEG, Abdulkader F, Laurindo FRM, Kowaltowski AJ, Chiaratti MR. Mice born to females with oocyte-specific deletion of mitofusin 2 have increased weight gain and impaired glucose homeostasis. Mol Hum Reprod 2020; 26:938-952. [PMID: 33118034 DOI: 10.1093/molehr/gaaa071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 08/27/2020] [Indexed: 12/19/2022] Open
Abstract
Offspring born to obese and diabetic mothers are prone to metabolic diseases, a phenotype that has been linked to mitochondrial dysfunction and endoplasmic reticulum (ER) stress in oocytes. In addition, metabolic diseases impact the architecture and function of mitochondria-ER contact sites (MERCs), changes which associate with mitofusin 2 (MFN2) repression in muscle, liver and hypothalamic neurons. MFN2 is a potent modulator of mitochondrial metabolism and insulin signaling, with a key role in mitochondrial dynamics and tethering with the ER. Here, we investigated whether offspring born to mice with MFN2-deficient oocytes are prone to obesity and diabetes. Deletion of Mfn2 in oocytes resulted in a profound transcriptomic change, with evidence of impaired mitochondrial and ER function. Moreover, offspring born to females with oocyte-specific deletion of Mfn2 presented increased weight gain and glucose intolerance. This abnormal phenotype was linked to decreased insulinemia and defective insulin signaling, but not mitochondrial and ER defects in offspring liver and skeletal muscle. In conclusion, this study suggests a link between disrupted mitochondrial/ER function in oocytes and increased risk of metabolic diseases in the progeny. Future studies should determine whether MERC architecture and function are altered in oocytes from obese females, which might contribute toward transgenerational transmission of metabolic diseases.
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Affiliation(s)
- Bruna M Garcia
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Thiago S Machado
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil.,Programa de Pós-Graduação em Anatomia dos Animais Domésticos e Silvestres, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo 05508-270, Brazil
| | - Karen F Carvalho
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Patrícia Nolasco
- Translational Cardiovascular Biology Unit, Instituto do Coração, Universidade de São Paulo, São Paulo 05403-904, Brazil
| | - Ricardo P Nociti
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga 13635-900, Brazil
| | - Maite Del Collado
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga 13635-900, Brazil
| | - Maria J D Capo Bianco
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Mateus P Grejo
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - José Djaci Augusto Neto
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Fabrícia H C Sugiyama
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Katiane Tostes
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil
| | - Anand K Pandey
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil.,Departament of Veterinary Gynaecology and Obstetrics, College of Veterinary Science, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar 125004, India
| | - Luciana M Gonçalves
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas 13083-865, Brazil
| | - Felipe Perecin
- Programa de Pós-Graduação em Anatomia dos Animais Domésticos e Silvestres, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo 05508-270, Brazil.,Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga 13635-900, Brazil
| | - Flávio V Meirelles
- Programa de Pós-Graduação em Anatomia dos Animais Domésticos e Silvestres, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo 05508-270, Brazil.,Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga 13635-900, Brazil
| | - José Bento S Ferraz
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga 13635-900, Brazil
| | - Emerielle C Vanzela
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas 13083-865, Brazil
| | - Antônio C Boschero
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas 13083-865, Brazil
| | - Francisco E G Guimarães
- Departamento de Física e Ciências dos Materiais, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos 13563-120, Brazil
| | - Fernando Abdulkader
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, Brazil
| | - Francisco R M Laurindo
- Translational Cardiovascular Biology Unit, Instituto do Coração, Universidade de São Paulo, São Paulo 05403-904, Brazil
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Marcos R Chiaratti
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil.,Programa de Pós-Graduação em Anatomia dos Animais Domésticos e Silvestres, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo 05508-270, Brazil
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8
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Chiaratti MR, Macabelli CH, Augusto Neto JD, Grejo MP, Pandey AK, Perecin F, Collado MD. Maternal transmission of mitochondrial diseases. Genet Mol Biol 2020; 43:e20190095. [PMID: 32141474 PMCID: PMC7197987 DOI: 10.1590/1678-4685-gmb-2019-0095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/01/2019] [Indexed: 12/19/2022] Open
Abstract
Given the major role of the mitochondrion in cellular homeostasis, dysfunctions of this organelle may lead to several common diseases in humans. Among these, maternal diseases linked to mitochondrial DNA (mtDNA) mutations are of special interest due to the unclear pattern of mitochondrial inheritance. Multiple copies of mtDNA are present in a cell, each encoding for 37 genes essential for mitochondrial function. In cases of mtDNA mutations, mitochondrial malfunctioning relies on mutation load, as mutant and wild-type molecules may co-exist within the cell. Since the mutation load associated with disease manifestation varies for different mutations and tissues, it is hard to predict the progeny phenotype based on mutation load in the progenitor. In addition, poorly understood mechanisms act in the female germline to prevent the accumulation of deleterious mtDNA in the following generations. In this review, we outline basic aspects of mitochondrial inheritance in mammals and how they may lead to maternally-inherited diseases. Furthermore, we discuss potential therapeutic strategies for these diseases, which may be used in the future to prevent their transmission.
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Affiliation(s)
- Marcos R Chiaratti
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Carolina H Macabelli
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - José Djaci Augusto Neto
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Mateus Priolo Grejo
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Anand Kumar Pandey
- Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Felipe Perecin
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
| | - Maite Del Collado
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
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9
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Ramzan F, D'Souza RF, Durainayagam BR, Milan AM, Roy NC, Kruger MC, Henry CJ, Mitchell CJ, Cameron-Smith D. Inflexibility of the plasma miRNA response following a high-carbohydrate meal in overweight insulin-resistant women. GENES AND NUTRITION 2020; 15:2. [PMID: 32042348 PMCID: PMC7001289 DOI: 10.1186/s12263-020-0660-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/15/2020] [Indexed: 12/14/2022]
Abstract
Context Metabolic inflexibility is a characteristic of insulin resistance, limiting the ability to transiently regulate oxidative metabolism and gene expression in response to nutrient availability. Little is known of the flexibility of post-transcriptional regulation, including circulatory miRNAs (c-miRNAs). Design The abundances of targeted c-miRNAs, with reported functions in metabolic regulation, were analysed in response to a high-carbohydrate meal in healthy weight insulin-sensitive (IS) and overweight insulin-resistant (IR) women. Participants Age-matched healthy weight IS (n = 20, BMI = 24.3 ± 0.70) and overweight IR (n = 20, BMI = 28.6 ± 0.67) women. Methods An abundance of c-miRNAs was quantified prior to and following a high-carbohydrate breakfast meal (2500 kJ; 50% carbohydrate, 20% fat and 27% protein). Target genes of the differentially regulated c-miRNA were measured in RNA extracted from circulatory peripheral blood mononuclear cells (PBMCs). Results In healthy weight IS women, both miR-15a-5p (p = 0.03) and miR-17-5p (p < 0.01) levels were halved at 4 h post-meal. These miRNA remained unaltered following the same meal in the overweight IR women. Furthermore, amongst genes targeted by these miRNA, CPT1A (p = 0.01) and IL8 (p = 0.03) had also reduced expression 4 h post-meal only in the healthy weight IS women. Conclusions The study findings provide preliminary evidence for a possible extension of metabolic inflexibility to include c-miRNAs. Trial registration The clinical trial is registered with Australian New Zealand Clinical Trials Registry under Trial registration: ANZCTR: ACTRN12615001108505. Registered on 21 October 2015.
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Affiliation(s)
- F Ramzan
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand.,2The Riddet Institute, Palmerston North, New Zealand
| | - R F D'Souza
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand.,3School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - B R Durainayagam
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand
| | - A M Milan
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand
| | - N C Roy
- 2The Riddet Institute, Palmerston North, New Zealand.,4Food Nutrition & Health Team, AgResearch Ltd, Palmerston North, New Zealand.,The High-Value Nutrition National Science Challenge, Auckland, New Zealand
| | - M C Kruger
- 6Institute of Food Science and Technology, Massey University, Palmerston North, New Zealand
| | - C J Henry
- 7Clinical Nutrition Research Centre, Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore, 117609 Singapore
| | - C J Mitchell
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand.,8School of Kinesiology, The University of British Columbia, Vancouver, Canada
| | - D Cameron-Smith
- 1The Liggins Institute, The University of Auckland, 85 Park Road, Grafton, Private Bag, 92019, Auckland, 1142 New Zealand.,2The Riddet Institute, Palmerston North, New Zealand.,9Food & Bio-Based Products Group, AgResearch Ltd, Palmerston North, New Zealand.,10Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (ASTAR), Singapore, 117609 Singapore
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10
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Chang YH, Lin HY, Shen FC, Su YJ, Chuang JH, Lin TK, Liou CW, Lin CY, Weng SW, Wang PW. The Causal Role of Mitochondrial Dynamics in Regulating Innate Immunity in Diabetes. Front Endocrinol (Lausanne) 2020; 11:445. [PMID: 32849261 PMCID: PMC7403198 DOI: 10.3389/fendo.2020.00445] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Plenty of evidence suggested that chronic low-grade inflammation triggered by innate immunity activation contributes to the pathogenesis of type 2 diabetes (T2D). Using the trans-mitochondrial cybrid cell model, we have demonstrated that mitochondria independently take part in the pathological process of insulin resistance (IR) and pro-inflammatory phenotype in cybrid cells harboring mitochondrial haplogroup B4, which are more likely to develop T2D. The mitochondrial network is more fragmented, and the expression of fusion-related proteins is low in Cybrid B4. We also discovered the causal role of mitochondrial dynamics (mtDYN) proteins in regulating IR in this cybrid model, and the bidirectional interaction between mtDYN and mitochondrial oxidative stress is considered etiologically important. In this study, we further investigated whether mtDYN bridges the gap between nutrient excess and chronic inflammation in T2D. Methods: Trans-mitochondrial cybrid cells derived from the 143B human osteosarcoma cell line were cultured in a medium containing glucose (25 mM) with or without saturated fatty acid (0.25 mM BSA-conjugated palmitate), and the expression of innate immunity/inflammasome molecules was compared between cybrid B4 (the major T2D-susceptible haplogroup among the Chinese population) and cybrid D4 (the major T2D-resistant haplogroup among the Chinese population). We investigated the causal relationship between mtDYN and nutrient excess-induced inflammation in cybrid B4 by genetic manipulation of mtDYN and by pharmacologically inhibiting mitochondrial fission using the Drp1 inhibitor, mdivi-1, and metformin. Results: Under nutrient excess with high fatty acid, cybrid B4 presented increased mitochondrial pro-fission profiles and enhanced chronic inflammation markers (RIG-I, MDA5, MAVS) and inflammasome (NLRP3, Caspase-1, IL-1β), whereas the levels in cybrid D4 were not or less significantly altered. In cybrid B4 under nutrient excess, overexpression of fusion proteins (Mfn1 or Mfn2) significantly repressed the expression of innate immunity/inflammasome-related molecules, while knockdown had a less significant effect. On the contrary, knockdown of fission proteins (Drp1 or Fis1) significantly repressed the expression of innate immunity/inflammasome-related molecules, while overexpression had a less significant effect. In addition, Drp1 inhibitor mdivi-1 and metformin inhibited mitochondrial fission and attenuated the pro-inflammation expression as well. Conclusion: Our results discovered the causal relationship between mtDYN and nutrient excess-induced chronic inflammation in a diabetes-susceptible cell model. Targeting mtDYN by direct interfering pro-fission can be a therapeutic intervention for chronic inflammation in T2D.
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Affiliation(s)
- Yen-Hsiang Chang
- Department of Nuclear Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Hung-Yu Lin
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Feng-Chih Shen
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yu-Jih Su
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Jiin-Haur Chuang
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tsu-Kung Lin
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chia-Wei Liou
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Ching-Yi Lin
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Shao-Wen Weng
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Pei-Wen Wang
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
- *Correspondence: Pei-Wen Wang
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11
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Gordaliza‐Alaguero I, Cantó C, Zorzano A. Metabolic implications of organelle-mitochondria communication. EMBO Rep 2019; 20:e47928. [PMID: 31418169 PMCID: PMC6726909 DOI: 10.15252/embr.201947928] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/10/2019] [Accepted: 05/28/2019] [Indexed: 12/31/2022] Open
Abstract
Cellular organelles are not static but show dynamism-a property that is likely relevant for their function. In addition, they interact with other organelles in a highly dynamic manner. In this review, we analyze the proteins involved in the interaction between mitochondria and other cellular organelles, especially the endoplasmic reticulum, lipid droplets, and lysosomes. Recent results indicate that, on one hand, metabolic alterations perturb the interaction between mitochondria and other organelles, and, on the other hand, that deficiency in proteins involved in the tethering between mitochondria and the ER or in specific functions of the interaction leads to metabolic alterations in a variety of tissues. The interaction between organelles is an emerging field that will permit to identify key proteins, to delineate novel modulation pathways, and to elucidate their implications in human disease.
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Affiliation(s)
- Isabel Gordaliza‐Alaguero
- Institute for Research in Biomedicine (IRB Barcelona)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- CIBER de Diabetes y Enfermedades Metabolicas AsociadasBarcelonaSpain
- Departamento de Bioquimica i Biomedicina MolecularFacultat de BiologiaUniversitat de BarcelonaBarcelonaSpain
| | - Carlos Cantó
- Nestle Institute of Health Sciences (NIHS)LausanneSwitzerland
- School of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- CIBER de Diabetes y Enfermedades Metabolicas AsociadasBarcelonaSpain
- Departamento de Bioquimica i Biomedicina MolecularFacultat de BiologiaUniversitat de BarcelonaBarcelonaSpain
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12
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Kristensen MD, Petersen SM, Møller KE, Lund MT, Hansen M, Hansen CN, Courraud J, Helge JW, Dela F, Prats C. Obesity leads to impairments in the morphology and organization of human skeletal muscle lipid droplets and mitochondrial networks, which are resolved with gastric bypass surgery-induced improvements in insulin sensitivity. Acta Physiol (Oxf) 2018; 224:e13100. [PMID: 29791782 DOI: 10.1111/apha.13100] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/29/2022]
Abstract
AIMS Skeletal muscle lipid stores and mitochondrial function have been appointed as key players in obesity-induced insulin resistance. However, there are conflicting reports in the literature based on in vitro quantitative measurements. Here, we test the hypothesis that it is not the quantity but the quality that matters. METHODS This study combines quantitative and qualitative structural measurements of lipid stores and mitochondrial dynamics in skeletal muscle from lean subjects, and subjects with morbid obesity, with and without type 2 diabetes, before and after gastric bypass surgery. RESULTS The structural organization of muscle mitochondrial networks in type II muscle fibres from subjects with morbid obesity is impaired. In addition, the amount of skeletal muscle perilipin 2 protein per intramyocellular lipid is reduced in subjects with morbid obesity, resulting in qualitative alterations in perilipin 2 coat around some lipid droplets. Gastric bypass surgery-induced weight loss and insulin resistance remission were associated with decreases in intramyocellular lipid stores and, qualitative improvements in lipid droplets' morphology, perilipin 2 coat and mitochondrial dynamics. CONCLUSION Morbid obesity leads to severe qualitative alterations of both skeletal muscle lipid stores and mitochondrial networks. The degree of structural improvements after gastric bypass surgery was proportional to the improvements in whole body insulin sensitivity, suggesting an association between these events.
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Affiliation(s)
- M. D. Kristensen
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - S. M. Petersen
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - K. E. Møller
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - M. T. Lund
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - M. Hansen
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - C. N Hansen
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - J. Courraud
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - J. W. Helge
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - F. Dela
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
- Department of Geriatrics; Bispebjerg University Hospital; Copenhagen Denmark
| | - C. Prats
- X-lab, Center for Healthy Aging; University of Copenhagen; Copenhagen Denmark
- Core Facility for Integrated Microscopy; Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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13
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Fealy CE, Mulya A, Axelrod CL, Kirwan JP. Mitochondrial dynamics in skeletal muscle insulin resistance and type 2 diabetes. Transl Res 2018; 202:69-82. [PMID: 30153426 DOI: 10.1016/j.trsl.2018.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/08/2018] [Accepted: 07/23/2018] [Indexed: 01/09/2023]
Abstract
The traditional view of mitochondria as isolated, spherical, energy producing organelles, is undergoing a revolutionary change. Emerging data show that mitochondria form a dynamic reticulum that is regulated by cycles of fission and fusion. The discovery of proteins that modulate these activities has led to important advances in understanding human disease. Here, we review the latest evidence that connects the emerging field of mitochondrial dynamics to skeletal muscle insulin resistance and propose some potential mechanisms that may explain the long debated link between mitochondria and the development of type 2 diabetes.
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Affiliation(s)
- CiarÁn E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Christopher L Axelrod
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana.
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14
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Ruegsegger GN, Creo AL, Cortes TM, Dasari S, Nair KS. Altered mitochondrial function in insulin-deficient and insulin-resistant states. J Clin Invest 2018; 128:3671-3681. [PMID: 30168804 DOI: 10.1172/jci120843] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Diabetes profoundly alters fuel metabolism; both insulin deficiency and insulin resistance are characterized by inefficient mitochondrial coupling and excessive production of reactive oxygen species (ROS) despite their association with normal to high oxygen consumption. Altered mitochondrial function in diabetes can be traced to insulin's pivotal role in maintaining mitochondrial proteome abundance and quality by enhancing mitochondrial biogenesis and preventing proteome damage and degradation, respectively. Although insulin enhances gene transcription, it also induces decreases in amino acids. Thus, if amino acid depletion is not corrected, increased transcription will not result in enhanced translation of transcripts to proteins. Mitochondrial biology varies among tissues, and although most studies in humans are performed in skeletal muscle, abnormalities have been reported in multiple organs in preclinical models of diabetes. Nutrient excess, especially fat excess, alters mitochondrial physiology by driving excess ROS emission that impairs insulin action. Excessive ROS irreversibly damages DNA and proteome with adverse effects on cellular functions. In insulin-resistant people, aerobic exercise stimulates both mitochondrial biogenesis and efficiency concurrent with enhancement of insulin action. This Review discusses the association between both insulin-deficient and insulin-resistant diabetes and alterations in mitochondrial proteome homeostasis and function that adversely affect cellular functions, likely contributing to many diabetic complications.
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15
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Scaini G, Quevedo J, Velligan D, Roberts DL, Raventos H, Walss-Bass C. Second generation antipsychotic-induced mitochondrial alterations: Implications for increased risk of metabolic syndrome in patients with schizophrenia. Eur Neuropsychopharmacol 2018; 28:369-380. [PMID: 29449054 DOI: 10.1016/j.euroneuro.2018.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/27/2017] [Accepted: 01/26/2018] [Indexed: 12/21/2022]
Abstract
Metabolic syndrome (MetS) is seen more frequently in persons with schizophrenia than in the general population, and these metabolic abnormalities are further aggravated by second generation antipsychotic (SGA) drugs. Although the underlying mechanisms responsible for the increased prevalence of MetS among patients under SGA treatment are not well understood, alterations in mitochondria function have been implicated. We performed a comprehensive evaluation of the role of mitochondrial dysfunction in the pathophysiology of drug-induced MetS in schizophrenia. We found a downregulation in genes encoding subunits of the electron transport chain complexes (ETC), enzyme activity, and mitochondrial dynamics in peripheral blood cells from patients at high-risk for MetS. Additionally, we evaluated several markers of energy metabolism in lymphoblastoid cell lines from patients with schizophrenia and controls following exposure to antipsychotics. We found that the high-risk drugs clozapine and olanzapine induced a general down-regulation of genes involved in the ETC, as well as decreased activities of the corresponding enzymes, ATP levels and a significant decrease in all the functional parameters of mitochondrial oxygen consumption in cells from patients and controls. We also observed that the medium-risk SGA quetiapine decreased oxygen consumption and respiratory control ratio in controls and patients. Additionally, clozapine and olanzapine induced a downregulation of Drp1 and Mfn2 both in terms of mRNA and protein levels. Together, these data suggest that an intrinsic defect in multiple components of oxidative metabolism may contribute to the increased prevalence of MetS in patients under treatment with SGAs known to cause risk for MetS.
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Affiliation(s)
- Giselli Scaini
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - João Quevedo
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Translational Psychiatry Laboratory, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Dawn Velligan
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - David L Roberts
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Henriette Raventos
- Centro de Investigacion en Biologia Celular y Molecular, University of Costa Rica, San Jose, Costa Rica
| | - Consuelo Walss-Bass
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.
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16
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Boulinguiez A, Staels B, Duez H, Lancel S. Mitochondria and endoplasmic reticulum: Targets for a better insulin sensitivity in skeletal muscle? Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:901-916. [PMID: 28529179 DOI: 10.1016/j.bbalip.2017.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 12/16/2022]
Abstract
Obesity and its associated metabolic disorders represent a major health burden, with economic and social consequences. Although adapted lifestyle and bariatric surgery are effective in reducing body weight, obesity prevalence is still rising. Obese individuals often become insulin-resistant. Obesity impacts on insulin responsive organs, such as the liver, adipose tissue and skeletal muscle, and increases the risk of cardiovascular diseases, type 2 diabetes and cancer. In this review, we discuss the effects of obesity and insulin resistance on skeletal muscle, an important organ for the control of postprandial glucose. The roles of mitochondria and the endoplasmic reticulum in insulin signaling are highlighted and potential innovative research and treatment perspectives are proposed.
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Affiliation(s)
- Alexis Boulinguiez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Bart Staels
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Hélène Duez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Steve Lancel
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
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17
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Theurey P, Rieusset J. Mitochondria-Associated Membranes Response to Nutrient Availability and Role in Metabolic Diseases. Trends Endocrinol Metab 2017; 28:32-45. [PMID: 27670636 DOI: 10.1016/j.tem.2016.09.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/13/2022]
Abstract
Metabolic diseases are associated with nutrient excess and metabolic inflexibility. Mitochondria and endoplasmic reticulum are important organelles and nutrient sensors, and their dysfunction has been extensively and independently implicated in metabolic diseases. Both organelles interact at sites known as mitochondria-associated membranes (MAMs), in order to exchange metabolites and calcium. Recent evidence indicates that MAM could be a hub of hepatic insulin signaling and nutrient sensing. In this review, we discuss the roles organelle function and communication play in the cell's adaptation to nutrient availability, in both physiology and metabolic diseases. We highlight how dynamic regulation of MAM affects mitochondria physiology and adaptation of cellular metabolism to nutrient availability, and how chronic MAM disruption participates in the metabolic inflexibility associated with metabolic disorders.
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Affiliation(s)
- Pierre Theurey
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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18
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Abstract
Mitochondrial architecture is involved in several functions crucial for cell viability, proliferation, senescence, and signaling. In particular, mitochondrial dynamics, through the balance between fusion and fission events, represents a central mechanism for bioenergetic adaptation to metabolic needs of the cell. As key regulators of mitochondrial dynamics, the fusogenic mitofusins have recently been linked to mitochondrial biogenesis and respiratory functions, impacting on cell fate and organism homeostasis. Here we review the implication of mitofusins in the regulation of mitochondrial metabolism, and their consequence on energy homeostasis at the cellular and physiological level, highlighting their crucial role in metabolic disorders, cancer, and aging.
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19
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Koliaki C, Roden M. Alterations of Mitochondrial Function and Insulin Sensitivity in Human Obesity and Diabetes Mellitus. Annu Rev Nutr 2016; 36:337-67. [PMID: 27146012 DOI: 10.1146/annurev-nutr-071715-050656] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondrial function refers to a broad spectrum of features such as resting mitochondrial activity, (sub)maximal oxidative phosphorylation capacity (OXPHOS), and mitochondrial dynamics, turnover, and plasticity. The interaction between mitochondria and insulin sensitivity is bidirectional and varies depending on tissue, experimental model, methodological approach, and features of mitochondrial function tested. In human skeletal muscle, mitochondrial abnormalities may be inherited (e.g., lower mitochondrial content) or acquired (e.g., impaired OXPHOS capacity and plasticity). Abnormalities ultimately lead to lower mitochondrial functionality due to or resulting in insulin resistance and type 2 diabetes mellitus. Similar mechanisms can also operate in adipose tissue and heart muscle. In contrast, mitochondrial oxidative capacity is transiently upregulated in the liver of obese insulin-resistant humans with or without fatty liver, giving rise to oxidative stress and declines in advanced fatty liver disease. These data suggest a highly tissue-specific interaction between insulin sensitivity and oxidative metabolism during the course of metabolic diseases in humans.
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Affiliation(s)
- Chrysi Koliaki
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf 40225, Germany.,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf 40225, Germany.,German Center for Diabetes Research (DZD e.V.), Düsseldorf 40225, Germany;
| | - Michael Roden
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf 40225, Germany.,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf 40225, Germany.,German Center for Diabetes Research (DZD e.V.), Düsseldorf 40225, Germany;
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20
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Zhang Y, Zhao YP, Gao YF, Fan ZM, Liu MY, Cai XY, Xia ZK, Gao CL. Silencing miR-106b improves palmitic acid-induced mitochondrial dysfunction and insulin resistance in skeletal myocytes. Mol Med Rep 2015; 11:3834-41. [PMID: 25529328 DOI: 10.3892/mmr.2014.3124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 10/24/2014] [Indexed: 11/06/2022] Open
Abstract
MicroRNA‑106b (miR‑106b) is reported to correlate closely with skeletal muscle insulin resistance. In the current study the effect of miR‑106b on palmitic acid (PA)‑induced mitochondrial dysfunction and insulin resistance was investigated in C2C12 myotubes via the silencing of miR‑106b. MiR‑106b expression was increased under PA treatment, while miR‑106b loss of function improved insulin sensitivity by upregulating its target mitofusin‑2 (Mfn2) in C2C12 myocytes. Furthermore, miR‑106b loss of function partly improved mitochondrial morphological lesions and increased the levels of mitochondial DNA and intracellular adenosine triphosphate that had been impaired by PA exposure in C2C12 myocytes. MiR‑106b loss of function attenuated the levels of intracellular reactive oxygen species (ROS), and upregulated the expression levels of the estrogen‑related receptor (ERR)‑α/peroxisome proliferative activated receptor γ coactivator (PGC)‑1α/Mfn2 axis under PA exposure. In addition, miR‑106b negatively regulated skeletal muscle mitochondrial function and insulin sensitivity under PA‑induced insulin resistance by targeting Mfn2, which may be associated with reduced ROS and upregulation of the ERR‑α/PGC‑1α/Mfn2 axis.
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Affiliation(s)
- Ying Zhang
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Ya-Ping Zhao
- Department of Pediatrics, The 82nd Hospital of the People's Liberation Army, Huai'an, Jiangsu 223001, P.R. China
| | - Yuan-Fu Gao
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Zhong-Min Fan
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Meng-Yuan Liu
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Xiao-Yi Cai
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Zheng-Kun Xia
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Chun-Lin Gao
- Department of Pediatrics, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, Jiangsu 210002, P.R. China
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21
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Zorzano A, Hernández-Alvarez MI, Sebastián D, Muñoz JP. Mitofusin 2 as a driver that controls energy metabolism and insulin signaling. Antioxid Redox Signal 2015; 22:1020-31. [PMID: 25567790 DOI: 10.1089/ars.2014.6208] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Mitochondrial dynamics is a complex process that impacts on mitochondrial biology. RECENT ADVANCES Recent evidence indicates that proteins participating in mitochondrial dynamics have additional cellular roles. Mitofusin 2 (Mfn2) is a potent modulator of mitochondrial metabolism with an impact on energy metabolism in muscle, liver, and hypothalamic neurons. In addition, Mfn2 is subjected to tight regulation. Hence, factors such as proinflammatory cytokines, lipid availability, or glucocorticoids block its expression, whereas exercise and increased energy expenditure promote its upregulation. CRITICAL ISSUES Importantly, Mfn2 controls cell metabolism and insulin signaling by limiting reactive oxygen species production and by modulation of endoplasmic reticulum stress. In this connection, it is critical to understand precisely the molecular mechanisms involved in the global actions of Mfn2. FUTURE DIRECTIONS Future directions should concentrate into the analysis of those mechanisms, and to fully demonstrate that Mfn2 represents a cellular hub that senses the metabolic and hormonal milieu and drives the control of metabolic homeostasis.
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Affiliation(s)
- Antonio Zorzano
- 1 Institute for Research in Biomedicine (IRB Barcelona) , Barcelona, Spain
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22
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Montgomery MK, Turner N. Mitochondrial dysfunction and insulin resistance: an update. Endocr Connect 2015; 4:R1-R15. [PMID: 25385852 PMCID: PMC4261703 DOI: 10.1530/ec-14-0092] [Citation(s) in RCA: 358] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction has been implicated in the development of insulin resistance (IR); however, a large variety of association and intervention studies as well as genetic manipulations in rodents have reported contrasting results. Indeed, even 39 years after the first publication describing a relationship between IR and diminished mitochondrial function, it is still unclear whether a direct relationship exists, and more importantly if changes in mitochondrial capacity are a cause or consequence of IR. This review will take a journey through the past and summarise the debate about the occurrence of mitochondrial dysfunction and its possible role in causing decreased insulin action in obesity and type 2 diabetes. Evidence is presented from studies in various human populations, as well as rodents with genetic manipulations of pathways known to affect mitochondrial function and insulin action. Finally, we have discussed whether mitochondria are a potential target for the treatment of IR.
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Affiliation(s)
- Magdalene K Montgomery
- Department of PharmacologyUNSW Medicine, School of Medical Sciences, University of New South Wales, Kensington, Sydney, New South Wales 2052, Australia
| | - Nigel Turner
- Department of PharmacologyUNSW Medicine, School of Medical Sciences, University of New South Wales, Kensington, Sydney, New South Wales 2052, Australia
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23
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Bereiter-Hahn J. Do we age because we have mitochondria? PROTOPLASMA 2014; 251:3-23. [PMID: 23794102 DOI: 10.1007/s00709-013-0515-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
The process of aging remains a great riddle. Production of reactive oxygen species (ROS) by mitochondria is an inevitable by-product of respiration, which has led to a hypothesis proposing the oxidative impairment of mitochondrial components (e.g., mtDNA, proteins, lipids) that initiates a vicious cycle of dysfunctional respiratory complexes producing more ROS, which again impairs function. This does not exclude other processes acting in parallel or targets for ROS action in other organelles than mitochondria. Given that aging is defined as the process leading to death, the role of mitochondria-based impairments in those organ systems responsible for human death (e.g., the cardiovascular system, cerebral dysfunction, and cancer) is described within the context of "garbage" accumulation and increasing insulin resistance, type 2 diabetes, and glycation of proteins. Mitochondrial mass, fusion, and fission are important factors in coping with impaired function. Both biogenesis of mitochondria and their degradation are important regulatory mechanisms stimulated by physical exercise and contribute to healthy aging. The hypothesis of mitochondria-related aging should be revised to account for the limitations of the degradative capacity of the lysosomal system. The processes involved in mitochondria-based impairments are very similar across a large range of organisms. Therefore, studies on model organisms from yeast, fungi, nematodes, flies to vertebrates, and from cells to organisms also add considerably to the understanding of human aging.
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Affiliation(s)
- Jürgen Bereiter-Hahn
- Institut für Zellbiologie und Neurowissenschaften, Goethe Universität Frankfurt am Main, Max-von-Lauestrasse 13, 60438, Frankfurt am Main, Germany,
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24
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Gao Y, Li F, Zhang A, Wang L, Tong W, Liu B. Evaluation of mitochondrial divisions in mouse with type-2 diabetes and effect of glucose-oxidase on mouse islet cells RIN-m5F. Cell Biol Int 2014; 38:368-73. [PMID: 24375791 DOI: 10.1002/cbin.10212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/27/2013] [Indexed: 01/07/2023]
Abstract
To elucidate the relationship between dynamic variations of insular β cell mitochondria and type-2 diabetes by using a mouse model, the dynamic variation (fusion or fission) of insular β cell mitochondria present in two groups of Wistar mice with type-2 diabetes (high fat feeding and streptozotocin (STZ) adding with low dose and high frequency, high fat feeding and STZ adding with high dose and low frequency), and normal Wistar mouse were systematically compared. By analysing the insulin secretion level and other related indexes, the molecular mechanism of the fusion or fission phenomenon of insular β cell mitochondria in two different models (high fat feeding and STZ adding with low dose and high frequency, high fat feeding and STZ adding with high dose and low frequency) of mice with type-2 diabetes were initially elucidated. The phenomenon of mitochondrial fusion and fission was clearly seen. In initially determining the relationship between the change of insular β cell mitochondrial structure and its cell apoptosis generated by some factors such as treatment by glucose-oxidase (GO), the effect of GO on the mouse islet cells RIN-m5F including the effects on cell growth, reactive oxygen species (ROS), cell cycle, cell apoptosis of RIN-m5F were systematically examined. GO showed some influence on the mouse islet cells RIN-m5F cell activity, ROS and apoptosis, but its effect on the cell cycle was not significant.
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Affiliation(s)
- Yu Gao
- Department of General Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China
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25
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Zhang Y, Yang L, Gao YF, Fan ZM, Cai XY, Liu MY, Guo XR, Gao CL, Xia ZK. MicroRNA-106b induces mitochondrial dysfunction and insulin resistance in C2C12 myotubes by targeting mitofusin-2. Mol Cell Endocrinol 2013; 381:230-40. [PMID: 23954742 DOI: 10.1016/j.mce.2013.08.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 08/01/2013] [Accepted: 08/05/2013] [Indexed: 11/16/2022]
Abstract
MicroRNA-106b (miR-106b) is reported to correlate closely with skeletal muscle insulin resistance and type 2 diabetes. The aim of this study was to identify an mRNA targeted by miR-106b which regulates skeletal muscle insulin sensitivity. MiR-106b was found to target the 3' untranslated region (3' UTR) of mitofusin-2 (Mfn2) through miR-106b binding sites and to downregulate Mfn2 protein abundance at the post-transcriptional level by luciferase activity assay combined with mutational analysis and immunoblotting. Overexpression of miR-106b resulted in mitochondrial dysfunction and insulin resistance in C2C12 myotubes. MiR-106b was increased in insulin-resistant cultured C2C12 myotubes induced by TNF-α, and accompanied by increasing Mfn2 level, miR-106b loss of function improved mitochondrial function and insulin sensitivity impaired by TNF-α in C2C12 myotubes. In addition, both overexpression and downregulation of miR-106b upregulated peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and estrogen-related receptor (ERR)-α expression. MiR-106b targeted Mfn2 and regulated skeletal muscle mitochondrial function and insulin sensitivity. Therefor, Inhibition of miR-106b may be a potential new strategy for treating insulin resistance and type 2 diabetes.
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Affiliation(s)
- Ying Zhang
- Department of Pediatrics, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, People's Republic of China
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26
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Segalés J, Paz JC, Hernández-Alvarez MI, Sala D, Muñoz JP, Noguera E, Pich S, Palacín M, Enríquez JA, Zorzano A. A form of mitofusin 2 (Mfn2) lacking the transmembrane domains and the COOH-terminal end stimulates metabolism in muscle and liver cells. Am J Physiol Endocrinol Metab 2013; 305:E1208-21. [PMID: 23941871 DOI: 10.1152/ajpendo.00546.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitofusin 2 (Mfn2), a protein that participates in mitochondrial fusion, is required to maintain normal mitochondrial metabolism in skeletal muscle and liver. Given that muscle Mfn2 is repressed in obese or type 2 diabetic subjects, this protein may have a potential pathophysiological role in these conditions. To evaluate whether the metabolic effects of Mfn2 can be dissociated from its function in mitochondrial dynamics, we studied a form of human Mfn2, lacking the two transmembrane domains and the COOH-terminal coiled coil (ΔMfn2). This form localized in mitochondria but did not alter mitochondrial morphology in cells or in skeletal muscle fibers. The expression of ΔMfn2 in mouse skeletal muscle stimulated glucose oxidation and enhanced respiratory control ratio, which occurred in the absence of changes in mitochondrial mass. ΔMfn2 did not stimulate mitochondrial respiration in Mfn2-deficient muscle cells. The expression of ΔMfn2 in mouse liver or in hepatoma cells stimulated gluconeogenesis. In addition, ΔMfn2 activated basal and maximal respiration both in muscle and liver cells. In all, we show that a form of Mfn2 lacking mitochondrial fusion activity stimulates mitochondrial function and enhances glucose metabolism in muscle and liver tissues. This study suggests that Mfn2 regulates metabolism independently of changes in mitochondrial morphology.
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Affiliation(s)
- Jessica Segalés
- Institute for Research in Biomedicine (IRB Barcelona Barcelona, Spain
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27
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Mingrone G, Castagneto-Gissey L, Macé K. Use of dicarboxylic acids in type 2 diabetes. Br J Clin Pharmacol 2013; 75:671-6. [PMID: 22242741 DOI: 10.1111/j.1365-2125.2012.04177.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Even-number, medium-chain dicarboxylic acids (DAs), naturally occurring in higher plants, are a promising alternative energy substrate. Unlike the homologous fatty acids, DAs are soluble in water as salts. They are β-oxidized, providing acetyl-CoA and succinyl-CoA, the latter being an intermediate of the tricarboxylic acid cycle. Sebacic acid and dodecanedioic acid, DAs with 10 and 12 carbon atoms respectively, provide 6.6 and 7.2 kcal g⁻¹ each; therefore, their energy density is intermediate between glucose and fatty acids. Dicarboxylic acids have been proved to be safe in both experimental animals and humans, and their use has recently been proposed in diabetes. Studies in animals and humans with type 2 diabetes showed that oral administration of sebacic acid improved glycaemic control, probably by enhancing insulin sensitivity, and reduced hepatic gluconeogenesis and glucose output. Moreover, dodecanedioic acid intake reduced muscle fatigue during exercise in subjects with type 2 diabetes, suggesting an improvement of energy utilization and 'metabolic flexibility'. In this article, we review the natural sources of DAs, their fate in animals and humans and their effect in improving glucose metabolism in type 2 diabetes.
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Affiliation(s)
- Geltrude Mingrone
- Department of Internal Medicine, Catholic University of Rome, Rome, Italy.
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28
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Obesity affects mitochondrial citrate synthase in human omental adipose tissue. ISRN OBESITY 2013; 2013:826027. [PMID: 24555156 PMCID: PMC3901984 DOI: 10.1155/2013/826027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/07/2013] [Indexed: 01/07/2023]
Abstract
The activities of some key enzymes in mitochondria from 135 human omental adipose tissue samples of obese and nonobese patients were analyzed for potential association with the patients' state of obesity. The activities of respiratory complexes I and II as well as citrate synthase in isolated mitochondria were measured using spectrophotometric enzyme assays. ATP generation of mitochondria was determined with a bioluminescence assay. Protein levels of citrate synthase were quantified by western blot. The rates of ATP generation and the enzymatic activities of complexes I and II did not display associations with age, gender, obesity, or diabetes. By contrast, the enzymatic activities of citrate synthase and its protein levels were significantly reduced in obesity as compared to controls. In diabetic patients, protein levels but not enzymatic activities of citrate synthase were elevated. Thus, this investigation based on enzymatic assay and determination of protein levels revealed that the development of obesity is associated with a significant impact on citrate synthase in mitochondria of human omental adipose tissue. The state of obesity appears to affect mitochondrial function in human omental adipose tissue by limiting this key enzyme of the tricarboxylic acid cycle rather than by limiting the activities of respiratory chain enzymes.
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29
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Anti-tumor effects of Mfn2 in gastric cancer. Int J Mol Sci 2013; 14:13005-21. [PMID: 23797661 PMCID: PMC3742171 DOI: 10.3390/ijms140713005] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/19/2013] [Accepted: 06/07/2013] [Indexed: 11/24/2022] Open
Abstract
Mitofusin-2 (Mfn2) is a mitochondrial outer membrane protein involved in mitochondrial fusion. Its mutation can cause Charcot-Marie-Tooth disease. Recent studies of Mfn2 in cancer research have not included gastric cancer. We confirmed that Mfn2 expression was lower in tumor tissue than in normal gastric mucosal tissue and that it was negatively correlated with tumor size, indicating an anti-tumor role for Mfn2. In vitro experiments showed that Mfn2 overexpression suppressed gastric cancer cell proliferation and colony formation, weakened the invasion and migratory ability of cancer cells by downregulating MMP-2 and MMP-9, halted the cell cycle and induced apoptosis. Western blotting indicated the likely involvement of P21 and PI3K/Akt signaling. Therefore, Mfn2 is a potential anti-tumor gene and a potential therapeutic target for treating gastric cancer. The progress of gastric cancer may be delayed by controlling Mfn2 expression.
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30
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Fuentes M, Andrews M, Arredondo-Olguín M. Effects of high iron and glucose concentrations over the relative expression of Bcl2, Bax, and Mfn2 in MIN6 cells. Biol Trace Elem Res 2013; 153:390-5. [PMID: 23605050 DOI: 10.1007/s12011-013-9666-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 04/08/2013] [Indexed: 12/28/2022]
Abstract
Type 2 diabetes is characterized by hyperglycemia and oxidative stress. Hyperglycemia is linked to mitochondrial dysfunction and reduced β-cell mass due to the reduced expression of genes such as Mfn2 as well as the participation of the Bcl2 gene family, responsible for increased apoptosis. The purpose of this study was to describe the effect of different iron and/or glucose concentrations over Mfn2, Bax, and Bcl2 expressions in a β-pancreatic cell line (MIN6 cells). MIN6 cells were pre-incubated with different iron and/or glucose concentrations, and the relative mRNA abundance of the Bcl2/Bax ratio and of Mfn2 genes was measured by qRT-PCR. Heme oxygenase (HO) activity, iron uptake, superoxide dismutase activity, and glutathione content were also determined. The Bcl2/Bax ratio increased and Mfn2 expression decreased in MIN6 cells after glucose stimulation. These effects were higher when glucose and iron were incubated together. Additionally, treatment with glucose/iron showed a higher HO activity. Our study revealed that high glucose/Fe concentrations in MIN6 cells induced an increase of the Bcl2/Bax ratio, an indicator of increased cell apoptosis.
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Affiliation(s)
- Marcela Fuentes
- Micronutrient Laboratory, Nutrition Institute and Food Technology, University of Chile, El Líbano 5524, Macul, Santiago, Chile
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31
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KONG DEXIAN, SONG GUANGYAO, WANG CHAO, MA HUIJUAN, REN LUPING, NIE QIAN, ZHANG XUEMEI, GAN KEXIN. Overexpression of mitofusin 2 improves translocation of glucose transporter 4 in skeletal muscle of high-fat diet-fed rats through AMP-activated protein kinase signaling. Mol Med Rep 2013; 8:205-10. [DOI: 10.3892/mmr.2013.1457] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 04/23/2013] [Indexed: 11/05/2022] Open
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32
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Picard M, Shirihai OS, Gentil BJ, Burelle Y. Mitochondrial morphology transitions and functions: implications for retrograde signaling? Am J Physiol Regul Integr Comp Physiol 2013; 304:R393-406. [PMID: 23364527 DOI: 10.1152/ajpregu.00584.2012] [Citation(s) in RCA: 212] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In response to cellular and environmental stresses, mitochondria undergo morphology transitions regulated by dynamic processes of membrane fusion and fission. These events of mitochondrial dynamics are central regulators of cellular activity, but the mechanisms linking mitochondrial shape to cell function remain unclear. One possibility evaluated in this review is that mitochondrial morphological transitions (from elongated to fragmented, and vice-versa) directly modify canonical aspects of the organelle's function, including susceptibility to mitochondrial permeability transition, respiratory properties of the electron transport chain, and reactive oxygen species production. Because outputs derived from mitochondrial metabolism are linked to defined cellular signaling pathways, fusion/fission morphology transitions could regulate mitochondrial function and retrograde signaling. This is hypothesized to provide a dynamic interface between the cell, its genome, and the fluctuating metabolic environment.
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Affiliation(s)
- Martin Picard
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA
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33
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Caloric restriction alters the metabolic response to a mixed-meal: results from a randomized, controlled trial. PLoS One 2012; 7:e28190. [PMID: 22523532 PMCID: PMC3327714 DOI: 10.1371/journal.pone.0028190] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 11/02/2011] [Indexed: 12/13/2022] Open
Abstract
Objectives To determine if caloric restriction (CR) would cause changes in plasma metabolic intermediates in response to a mixed meal, suggestive of changes in the capacity to adapt fuel oxidation to fuel availability or metabolic flexibility, and to determine how any such changes relate to insulin sensitivity (SI). Methods Forty-six volunteers were randomized to a weight maintenance diet (Control), 25% CR, or 12.5% CR plus 12.5% energy deficit from structured aerobic exercise (CR+EX), or a liquid calorie diet (890 kcal/d until 15% reduction in body weight)for six months. Fasting and postprandial plasma samples were obtained at baseline, three, and six months. A targeted mass spectrometry-based platform was used to measure concentrations of individual free fatty acids (FFA), amino acids (AA), and acylcarnitines (AC). SI was measured with an intravenous glucose tolerance test. Results Over three and six months, there were significantly larger differences in fasting-to-postprandial (FPP) concentrations of medium and long chain AC (byproducts of FA oxidation) in the CR relative to Control and a tendency for the same in CR+EX (CR-3 month P = 0.02; CR-6 month P = 0.002; CR+EX-3 month P = 0.09; CR+EX-6 month P = 0.08). After three months of CR, there was a trend towards a larger difference in FPP FFA concentrations (P = 0.07; CR-3 month P = 0.08). Time-varying differences in FPP concentrations of AC and AA were independently related to time-varying SI (P<0.05 for both). Conclusions Based on changes in intermediates of FA oxidation following a food challenge, CR imparted improvements in metabolic flexibility that correlated with improvements in SI. Trial Registration ClinicalTrials.gov NCT00099151
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Tang WX, Wu WH, Zeng XX, Bo H, Huang SM. Early protective effect of mitofusion 2 overexpression in STZ-induced diabetic rat kidney. Endocrine 2012; 41:236-47. [PMID: 22095488 DOI: 10.1007/s12020-011-9555-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/27/2011] [Indexed: 02/05/2023]
Abstract
Diabetic nephropathy (DN) is a serious complication of diabetes with a poorly defined etiology and limited treatment options. Early intervention is key to preventing the progression of DN. Mitofusin 2 (Mfn2) regulates mitochondrial morphology and signaling, and is involved in the pathogenesis of numerous diseases. Furthermore, Mfn2 is also closely associated with the development of diabetes, but its functional roles in the diabetic kidney remain unknown. This study investigated the effect of Mfn2 at an early stage of DN. Mfn2 was overexpressed by adenovirus-mediated gene transfer in streptozotocin-induced diabetic rats. Clinical parameters (proteinuria, albumin/creatinine ratio), pathological changes, ultra-microstructural changes in nephrons, expression of collagen IV and phosph-p38, ROS production, mitochondrial function, and apoptosis were evaluated and compared with diabetic rats expressing control levels of Mfn2. Endogenous Mfn2 expression decreased with time in DN. Compared to the blank transfection control group, overexpression of Mfn2 decreased kidney weight relative to body weight, reduced proteinuria and ACR, and improved pathological changes typical of the diabetic kidney, like enlargement of glomeruli, accumulation of ECM, and thickening of the basement membrane. In addition, Mfn2 overexpression inhibited activation of p38, and the accumulation of ROS; prevented mitochondrial dysfunction; and reduced the synthesis of collagen IV, but did not affect apoptosis of kidney cells. This study demonstrates that Mfn2 overexpression can attenuate pathological changes in the kidneys of diabetic rats. Further studies are needed to clarify the underlying mechanism of this protective function. Mfn2 might be a potential therapeutic target for the treatment of early stage DN.
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Affiliation(s)
- Wan Xin Tang
- Division of Nephrology, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
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35
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Mitochondrial dysregulation in the pathogenesis of diabetes: potential for mitochondrial biogenesis-mediated interventions. EXPERIMENTAL DIABETES RESEARCH 2011; 2012:642038. [PMID: 22203837 PMCID: PMC3235780 DOI: 10.1155/2012/642038] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/08/2011] [Indexed: 12/25/2022]
Abstract
Muscle mitochondrial metabolism is a tightly controlled process that involves the coordination of signaling pathways and factors from both the nuclear and mitochondrial genomes. Perhaps the most important pathway regulating metabolism in muscle is mitochondrial biogenesis. In response to physiological stimuli such as exercise, retrograde signaling pathways are activated that allow crosstalk between the nucleus and mitochondria, upregulating hundreds of genes and leading to higher mitochondrial content and increased oxidation of substrates. With type 2 diabetes, these processes can become dysregulated and the ability of the cell to respond to nutrient and energy fluctuations is diminished. This, coupled with reduced mitochondrial content and altered mitochondrial morphology, has been directly linked to the pathogenesis of this disease. In this paper, we will discuss our current understanding of mitochondrial dysregulation in skeletal muscle as it relates to type 2 diabetes, placing particular emphasis on the pathways of mitochondrial biogenesis and mitochondrial dynamics, and the therapeutic value of exercise and other interventions.
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Baile CA, Yang JY, Rayalam S, Hartzell DL, Lai CY, Andersen C, Della-Fera MA. Effect of resveratrol on fat mobilization. Ann N Y Acad Sci 2011; 1215:40-7. [PMID: 21261640 DOI: 10.1111/j.1749-6632.2010.05845.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Higher levels of body fat are associated with increased risk for development of numerous adverse health conditions. Phytochemicals are potential agents to inhibit differentiation of preadipocytes, stimulate lipolysis, and induce apoptosis of existing adipocytes, thereby reducing adipose tissue mass. Resveratrol decreased adipogenesis and viability in maturing preadipocytes; these effects were mediated not only through down-regulating adipocyte specific transcription factors and enzymes but also by genes that modulate mitochondrial function. Additionally, resveratrol increased lipolysis and reduced lipogenesis in mature adipocytes. In addition, combining resveratrol with other natural products produced synergistic activities from actions on multiple molecular targets in the adipocyte life cycle. Treatment of mice with resveratrol alone was shown to improve resistance to weight gain caused by a high-fat diet. Moreover, dietary supplementation of aged ovariectomized rats with a combination of resveratrol and vitamin D, quercetin, and genistein not only decreased weight gain but also inhibited bone loss. Combining several phytochemicals, including resveratrol, or using them as templates for synthesizing new drugs, provides a large potential for using phytochemicals to target adipocyte adipogenesis, apoptosis, and lipolysis.
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Seo AY, Joseph AM, Dutta D, Hwang JCY, Aris JP, Leeuwenburgh C. New insights into the role of mitochondria in aging: mitochondrial dynamics and more. J Cell Sci 2011; 123:2533-42. [PMID: 20940129 DOI: 10.1242/jcs.070490] [Citation(s) in RCA: 377] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A decline in mitochondrial function plays a key role in the aging process and increases the incidence of age-related disorders. A deeper understanding of the intricate nature of mitochondrial dynamics, which is described as the balance between mitochondrial fusion and fission, has revealed that functional and structural alterations in mitochondrial morphology are important factors in several key pathologies associated with aging. Indeed, a recent wave of studies has demonstrated the pleiotropic role of fusion and fission proteins in numerous cellular processes, including mitochondrial metabolism, redox signaling, the maintenance of mitochondrial DNA and cell death. Additionally, mitochondrial fusion and fission, together with autophagy, have been proposed to form a quality-maintenance mechanism that facilitates the removal of damaged mitochondria from the cell, a process that is particularly important to forestall aging. Thus, dysfunctional regulation of mitochondrial dynamics might be one of the intrinsic causes of mitochondrial dysfunction, which contributes to oxidative stress and cell death during the aging process. In this Commentary, we discuss recent studies that have converged at a consensus regarding the involvement of mitochondrial dynamics in key cellular processes, and introduce a possible link between abnormal mitochondrial dynamics and aging.
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Affiliation(s)
- Arnold Y Seo
- Department of Aging and Geriatric Research, College of Medicine, Institute on Aging, University of Florida, Gainesville, FL 32611, USA
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Mutation of the protein kinase A phosphorylation site influences the anti-proliferative activity of mitofusin 2. Atherosclerosis 2010; 211:216-23. [DOI: 10.1016/j.atherosclerosis.2010.02.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/05/2010] [Accepted: 02/08/2010] [Indexed: 11/23/2022]
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39
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Liver-specific reduction of Mfn2 protein by RNAi results in impaired glycometabolism and lipid homeostasis in BALB/c mice. ACTA ACUST UNITED AC 2009; 29:689-96. [PMID: 20037808 DOI: 10.1007/s11596-009-0603-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Indexed: 12/13/2022]
Abstract
Mitofusin-2 (Mfn2) gene expression is positively correlated with insulin sensitivity in patients with type 2 diabetes. However, it is unclear if Mfn2 is involved in carbohydrate metabolism and lipid homeostasis. In order to investigate the specific functions of Mfn2 in glycometabolism and lipid homeostasis in BALB/c mice, a RNA interference technique-mediated hydrodynamic injection was developed, in which short hairpin RNAs (shRNAs) were used to inhibit the Mfn2 expression in vivo. Seventy-two mice were randomly divided into two groups: the Mfn2 reduction group (Mfn2/shRNA) and the negative control group (NC). Intraperitoneal glucose tolerance tests and intraperitoneal insulin tolerance tests were used to evaluate glycometabolism and insulin sensitivity. D-(3-3H) glucose or 3H2O was injected into the tail vein or intraperitoneally to facilitate the calculation of the rate of hepatic glucose production and fatty acid synthesis in vivo. The results showed that, in Mfn2/shRNA mice, the liver Mfn2 protein was significantly decreased, and fasting blood glucose concentrations were increased by approximately 48%, when compared with the NC mice. In parallel with the changes in fasting glucose levels, hepatic glucose production was significantly elevated in Mfn2/shRNA mice. When insulin was administrated, these mice exhibited impaired insulin tolerance. It was also found that the reduction of Mfn2 markedly decreased the rate of fatty acid synthesis in the liver, and the Mfn2/shRNA mice exhibited hypertriglyceridema. Taken together, our results indicate that Mfn2 plays an important role in maintaining glucose and lipid homeostasis, and in the development of insulin resistance in vivo.
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Lindinger A, Peterli R, Peters T, Kern B, von Flüe M, Calame M, Hoch M, Eberle AN, Lindinger PW. Mitochondrial DNA content in human omental adipose tissue. Obes Surg 2009; 20:84-92. [PMID: 19826890 DOI: 10.1007/s11695-009-9987-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 09/22/2009] [Indexed: 12/18/2022]
Abstract
BACKGROUND Impairment of mitochondrial function plays an important role in obesity and the development of insulin resistance. The aim of this project was to investigate the mitochondrial DNA copy number in human omental adipose tissue with respect to obesity. METHODS The mitochondrial DNA (mtDNA) content per single adipocyte derived from abdominal omental adipose tissue was determined by quantitative RT-PCR in a group of 75 patients, consisting of obese and morbidly obese subjects, as well as non-obese controls. Additionally, basal metabolic rate and fat oxidation rate were recorded and expressed as total values or per kilogram fat mass. RESULTS MtDNA content is associated with obesity. Higher body mass index (BMI) resulted in a significantly elevated mtDNA count (ratio = 1.56; p = 0.0331) comparing non-obese (BMI < 30) to obese volunteers (BMI >or= 30). The mtDNA count per cell was not correlated with age or gender. Diabetic patients showed a trend toward reduced mtDNA content. A seasonal change in mtDNA copy number could not be identified. In addition, a substudy investigating the basal metabolic rate and the fasting fat oxidation did not reveal any associations to the mtDNA count. CONCLUSIONS The mtDNA content per cell of omental adipose tissue did not correlate with various clinical parameters but tended to be reduced in patients with diabetes, which may partly explain the impairment of mitochondrial function observed in insulin resistance. Furthermore, the mtDNA content was significantly increased in patients suffering from obesity (BMI above 30). This might reflect a compensatory response to the development of obesity, which is associated with impairment of mitochondrial function.
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Role of mitochondrial dynamics proteins in the pathophysiology of obesity and type 2 diabetes. Int J Biochem Cell Biol 2009; 41:1846-54. [DOI: 10.1016/j.biocel.2009.02.004] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 02/03/2009] [Accepted: 02/10/2009] [Indexed: 02/08/2023]
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Liesa M, Palacín M, Zorzano A. Mitochondrial dynamics in mammalian health and disease. Physiol Rev 2009; 89:799-845. [PMID: 19584314 DOI: 10.1152/physrev.00030.2008] [Citation(s) in RCA: 686] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.
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Affiliation(s)
- Marc Liesa
- Institute for Research in Biomedicine (IRB Barcelona), CIBER de Diabetes y Enfermedades Metabólicas Asociadas, and Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Barcelona 08028, Spain
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Hernández-Alvarez MI, Chiellini C, Manco M, Naon D, Liesa M, Palacín M, Mingrone G, Zorzano A. Genes involved in mitochondrial biogenesis/function are induced in response to bilio-pancreatic diversion in morbidly obese individuals with normal glucose tolerance but not in type 2 diabetic patients. Diabetologia 2009; 52:1618-27. [PMID: 19504086 DOI: 10.1007/s00125-009-1403-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 04/20/2009] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS The mechanisms allowing normalisation of insulin sensitivity and reversal of type 2 diabetes after bilio-pancreatic diversion (BPD) have not been elucidated. We studied whether the expression of genes relevant to mitochondrial biogenesis/function is induced in response to BPD and whether the response differs between morbidly obese patients with normal glucose tolerance (NGT) and patients with type 2 diabetes. METHODS The effect of stable weight reduction after BPD on metabolic variables and expression of nuclear genes encoding for mitochondrial proteins or regulators of mitochondrial function was investigated in skeletal muscle. Insulin sensitivity was assessed by euglycaemic-hyperinsulinaemic clamp and substrate oxidation by indirect calorimetry. RESULTS Both NGT and type 2 diabetic patients showed a net improvement of insulin sensitivity, with the latter also showing blood glucose normalisation. NGT patients had a large increase in glucose oxidation and substantial reduction in lipid oxidation. In contrast, type 2 diabetic patients had a blunted response to BPD in terms of glucose oxidation. NGT patients showed increased expression of genes encoding mitofusin 2, porin or citrate synthase; no significant changes were detected in diabetic patients. The expression of genes regulating mitochondrial activity (PGC-1beta [also known as PPARGC1B], PGC-1alpha [also known as PPARGC1A], PPARdelta [also known as PPARD], SIRT1) was induced only in NGT patients. CONCLUSIONS/INTERPRETATION These findings indicate that weight loss after BPD exerts a beneficial effect on insulin sensitivity via mechanisms that are independent of the expression of genes involved in mitochondrial biogenesis/activity. Furthermore, the observation that gene expression is not altered with weight loss in type 2 diabetic patients while it is induced in NGT patients suggests a heritable component.
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Affiliation(s)
- M I Hernández-Alvarez
- Institute for Research in Biomedicine, Parc Cientific de Barcelona, 08028 Barcelona, Spain
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Zorzano A. Regulation of mitofusin-2 expression in skeletal muscleThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process. Appl Physiol Nutr Metab 2009; 34:433-9. [DOI: 10.1139/h09-049] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fusion and fission of mitochondria regulate their morphology and distribution. Mitofusin-2 (Mfn2) is a mitochondrial protein involved in such fusion. Recent observations indicate that Mfn2 is a multifunctional protein that participates in cell proliferation and metabolism and that it is required for normal endoplasmic reticulum morphology. In relation to the metabolic role of Mfn2, alterations in activity have been reported to modify cell respiration, substrate oxidation, and oxidative phosphorylation subunit expression in cultured nonmuscle and muscle cells. Mfn2 expression in skeletal muscle is subject to regulation and conditions characterized by reduced mitochondrial activity, such as obesity or type 2 diabetes, and are associated with repressed Mfn2 . In contrast, cold-exposure treatment with β3-adrenergic agonists or exercise induce the expression of this gene in muscle. Estrogen-related receptor-α transcription factor is a key regulator of Mfn2 transcription and recruits peroxisome proliferator-activated receptor γ coactivator (PGC)-1β and PGC-1α. These 2 nuclear coactivators are potent, positive regulators of Mfn2 expression in muscle cells, and ablation of PGC-1β causes Mfn2 downregulation in skeletal muscle and in the heart. We propose that PGC-1β is a regulator of normal expression of Mfn2 in muscle, whereas PGC-1α participates in the stimulation of Mfn2 expression under a variety of conditions characterized by enhanced energy expenditure.
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Affiliation(s)
- Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), C/Baldiri Reixac 10, Barcelona 08028, Spain
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, Barcelona 08028, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) (e-mail: )
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Hom J, Sheu SS. Morphological dynamics of mitochondria--a special emphasis on cardiac muscle cells. J Mol Cell Cardiol 2009; 46:811-20. [PMID: 19281816 DOI: 10.1016/j.yjmcc.2009.02.023] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 02/22/2009] [Accepted: 02/25/2009] [Indexed: 01/10/2023]
Abstract
Mitochondria play a critical role in cellular energy metabolism, Ca(2+) homeostasis, reactive oxygen species generation, apoptosis, aging, and development. Many recent publications have shown that a continuous balance of fusion and fission of these organelles is important in maintaining their proper function. Therefore, there is a steep correlation between the form and function of mitochondria. Many major proteins involved in mitochondrial fusion and fission have been identified in different cell types, including heart. However, the functional role of mitochondrial dynamics in the heart remains, for the most part, unexplored. In this review we will cover the recent field of mitochondrial dynamics and its physiological and pathological implications, with a particular emphasis on the experimental and theoretical basis of mitochondrial dynamics in the heart.
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Affiliation(s)
- Jennifer Hom
- Department of Pharmacology and Physiology, Mitochondrial Research and Innovation Group, University of Rochester Medical Center, Rochester, NY 14642, USA
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Zorzano A, Liesa M, Palacín M. Mitochondrial dynamics as a bridge between mitochondrial dysfunction and insulin resistance. Arch Physiol Biochem 2009; 115:1-12. [PMID: 19267277 DOI: 10.1080/13813450802676335] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Muscle from obese subjects or from type 2 diabetic patients show mitochondrial dysfunction, and this may participate in the insulin resistance in those conditions. The mechanisms involved in mitochondrial dysfunction are not completely understood. Dynamic mitochondrial filaments or networks form by mitochondrial fusion and fission events. There is substantial evidence that proteins participating in mitochondrial fusion or fission also have a role in metabolism. Thus, mitofusin-2 (Mfn2) a mitochondrial fusion protein, stimulates respiration, substrate oxidation and OXPHOS subunits expression. In this regard, muscle from obese subjects, or from type 2 diabetic patients, show a reduced expression of Mfn2 and, amelioration of insulin sensitivity by bariatric surgery is associated with an increased Mfn2 expression in muscle. Here, we propose the hypothesis that mitochondrial dynamics proteins play a role in mitochondrial dysfunction in obesity or in type 2 diabetes and that it may also participate in the development of insulin resistance.
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Affiliation(s)
- Antonio Zorzano
- Institute for Research in Biomedicine, Baldiri Reixac, Barcelona, Spain.
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Rayalam S, Yang JY, Ambati S, Della-Fera MA, Baile CA. Resveratrol induces apoptosis and inhibits adipogenesis in 3T3-L1 adipocytes. Phytother Res 2008; 22:1367-71. [PMID: 18688788 DOI: 10.1002/ptr.2503] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Resveratrol, a phytoallexin, has recently been reported to slow aging by acting as a sirtuin activator. Resveratrol also has a wide range of pharmacological effects on adipocytes. In this study, we investigated the effects of resveratrol on adipogenesis and apoptosis using 3T3-L1 cells. In mature adipocytes, 100 and 200 microM resveratrol decreased cell viability dose-dependently by 23 +/- 2.7%, and 75.3 +/- 2.8% (p < 0.0001), respectively, after 48 h treatment, and 100 microM resveratrol increased apoptosis by 76 +/- 8.7% (p < 0.0001). Resveratrol at 25 and 50 microM decreased lipid accumulation in maturing preadipocytes significantly by 43 +/- 1.27% and 94.3 +/- 0.3% (p < 0.0001) and decreased cell viability by 25 +/- 1.3% and 70.4 +/- 1.6% (p < 0.0001), respectively. In order to understand the anti-adipogenic effects of resveratrol, maturing 3T3-L1 preadipocytes were treated with 25 microM resveratrol and the change in the expression of several adipogenic transcription factors and enzymes was investigated using real-time RT-PCR. Resveratrol down-regulated the expression of PPAR gamma, C/EBP alpha, SREBP-1c, FAS, HSL, LPL and up-regulated the expression of genes regulating mitochondrial activity (SIRT3, UCP1 and Mfn2). These results indicate that resveratrol may alter fat mass by directly affecting cell viability and adipogenesis in maturing preadipocytes and inducing apoptosis in adipocytes and thus may have applications for the treatment of obesity.
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Affiliation(s)
- Srujana Rayalam
- Department of Animal & Dairy Science, University of Georgia, Athens, GA 30602-2771, USA
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Abstract
Metabolic flexibility is the capacity for the organism to adapt fuel oxidation to fuel availability. The inability to modify fuel oxidation in response to changes in nutrient availability has been implicated in the accumulation of intramyocellular lipid and insulin resistance. The metabolic flexibility assessed by the ability to switch from fat to carbohydrate oxidation is usually impaired during a hyperinsulinemic clamp in insulin-resistant subjects; however, this "metabolic inflexibility" is mostly the consequence of impaired cellular glucose uptake. Indeed, after controlling for insulin-stimulated glucose disposal rate (amount of glucose available for oxidation), metabolic flexibility is not altered in obesity regardless of the presence of type 2 diabetes. To understand how intramyocellular lipids accumulate and cause insulin resistance, the assessment of metabolic flexibility to high-fat diets is more relevant than metabolic flexibility during a hyperinsulinemic clamp. An impaired capacity to upregulate muscle lipid oxidation in the face of high lipid supply may lead to increased muscle fat accumulation and insulin resistance. Surprisingly, very few studies have investigated the response to high-fat diets. In this review, we discuss the role of glucose disposal rate, adipose tissue lipid storage, and mitochondrial function on metabolic flexibility. Additionally, we emphasize the bias of using the change in respiratory quotient to calculate metabolic flexibility and propose novel approaches to assess metabolic flexibility. On the basis of current evidence, one cannot conclude that impaired metabolic flexibility is responsible for the accumulation of intramyocellular lipid and insulin resistance. We propose to study metabolic flexibility in response to high-fat diets in individuals having contrasting degree of insulin sensitivity and/or mitochondrial characteristics.
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Affiliation(s)
- Jose E Galgani
- Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA
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Zhang W, Della-Fera MA, Hartzell DL, Hausman D, Baile CA. Adipose tissue gene expression profiles in ob/ob mice treated with leptin. Life Sci 2008; 83:35-42. [PMID: 18547592 DOI: 10.1016/j.lfs.2008.04.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 04/19/2008] [Accepted: 04/25/2008] [Indexed: 12/22/2022]
Abstract
Leptin plays a critical role in regulating body weight, lipid metabolism, apoptosis and microvasculature of adipose tissue. To explore multiple signaling pathways of leptin action on adipose tissue, real-time PCR utilizing TaqMan low-density arrays was performed to compare mRNA expression in adipose tissue of ob/ob mice treated with vehicle or leptin (2.5 microg/d or 10 microg/d) for 14 days via subcutaneous osmotic minipumps. Of the 24 target genes selected for characterization, many were differentially expressed between control ob/ob mice and leptin-treated ob/ob mice. Increases in mRNA expression were found for hormone sensitive lipase (HSL), uncoupling protein 2 (UCP2), adrenergic receptor 3 (ADR3), mitofusin 2 (Mfn2), sirtuin 3 (Sirt3), transcription factor sterol regulatory element binding factor 1 (SREBF1), Bcl-2, Bax, Caspase 3, tumor necrosis factor alpha (TNFalpha), adiponectin and angiopoietin 2 (Ang-2). Decreases in expression were found for stearoyl-coenzyme A desaturase 1 (SCD1), fatty acid synthase (FAS), and retinol binding protein 4 (RBP4). There were no changes in expression of transcription factors involved in adipocyte differentiation (C/EBPalpha, PPARalpha, and PPARgamma). These results confirm that alterations in the expression of specific adipose tissue genes including those associated with the promotion of lipid mobilization, energy dissipation, and apoptosis may mediate leptin-induced fat loss in ob/ob mice.
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Affiliation(s)
- Wei Zhang
- Department of Foods & Nutrition, University of Georgia, Athens, GA 30602-2271, USA
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de Brito OM, Scorrano L. Mitofusin 2: a mitochondria-shaping protein with signaling roles beyond fusion. Antioxid Redox Signal 2008; 10:621-33. [PMID: 18092941 DOI: 10.1089/ars.2007.1934] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mitochondria are central organelles in metabolism, signal transduction, and programmed cell death. To meet their diverse functional demands, their shape is strictly regulated by a growing family of proteins that impinge on fission and fusion of the organelle. Mitochondrial fusion depends on Mitofusin (Mfn) 1 and 2, two integral outer-membrane proteins. Although MFN1 seems primarily involved in the regulation of the docking and fusion of the organelle, mounting evidence is implicating MFN2 in multiple signaling pathways not restricted to the regulation of mitochondrial shape. Here we review data supporting a role for this mitochondria-shaping protein beyond fusion, in regulating mitochondrial metabolism, apoptosis, shape of other organelles, and even progression through cell cycle. In conclusion, MFN2 appears a multifunctional protein whose biologic function is not restricted to the regulation of mitochondrial shape.
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