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Cai J, Wang F, Shao M. The Emerging Importance of Mitochondria in White Adipocytes: Neither Last nor Least. Endocrinol Metab (Seoul) 2023; 38:493-503. [PMID: 37816498 PMCID: PMC10613775 DOI: 10.3803/enm.2023.1813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/05/2023] [Accepted: 09/14/2023] [Indexed: 10/12/2023] Open
Abstract
The growing recognition of mitochondria's crucial role in the regulation of white adipose tissue remodeling and energy balance underscores its significance. The marked metabolic diversity of mitochondria provides the molecular and cellular foundation for enabling adipose tissue plasticity in response to various metabolic cues. Effective control of mitochondrial function at the cellular level, not only in thermogenic brown and beige adipocytes but also in energy-storing white adipocytes, exerts a profound influence on adipose homeostasis. Furthermore, mitochondria play a pivotal role in intercellular communication within adipose tissue via production of metabolites with signaling properties. A more comprehensive understanding of mitochondrial regulation within white adipocytes will empower the development of targeted and efficacious strategies to enhance adipose function, leading to advancements in overall metabolic health.
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Affiliation(s)
- Juan Cai
- CAS Key Laboratory of Molecular Virology and Immunology, The Center for Microbes, Development and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Fenfen Wang
- Department of Anesthesiology, Critical Care and Pain Medicine, Center for Perioperative Medicine, McGovern Medical School, UT Health Science Center at Houston, Houston, TX, USA
| | - Mengle Shao
- CAS Key Laboratory of Molecular Virology and Immunology, The Center for Microbes, Development and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
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2
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Chen L, Zhou M, Li H, Liu D, Liao P, Zong Y, Zhang C, Zou W, Gao J. Mitochondrial heterogeneity in diseases. Signal Transduct Target Ther 2023; 8:311. [PMID: 37607925 PMCID: PMC10444818 DOI: 10.1038/s41392-023-01546-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 02/21/2023] [Accepted: 06/13/2023] [Indexed: 08/24/2023] Open
Abstract
As key organelles involved in cellular metabolism, mitochondria frequently undergo adaptive changes in morphology, components and functions in response to various environmental stresses and cellular demands. Previous studies of mitochondria research have gradually evolved, from focusing on morphological change analysis to systematic multiomics, thereby revealing the mitochondrial variation between cells or within the mitochondrial population within a single cell. The phenomenon of mitochondrial variation features is defined as mitochondrial heterogeneity. Moreover, mitochondrial heterogeneity has been reported to influence a variety of physiological processes, including tissue homeostasis, tissue repair, immunoregulation, and tumor progression. Here, we comprehensively review the mitochondrial heterogeneity in different tissues under pathological states, involving variant features of mitochondrial DNA, RNA, protein and lipid components. Then, the mechanisms that contribute to mitochondrial heterogeneity are also summarized, such as the mutation of the mitochondrial genome and the import of mitochondrial proteins that result in the heterogeneity of mitochondrial DNA and protein components. Additionally, multiple perspectives are investigated to better comprehend the mysteries of mitochondrial heterogeneity between cells. Finally, we summarize the prospective mitochondrial heterogeneity-targeting therapies in terms of alleviating mitochondrial oxidative damage, reducing mitochondrial carbon stress and enhancing mitochondrial biogenesis to relieve various pathological conditions. The possibility of recent technological advances in targeted mitochondrial gene editing is also discussed.
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Affiliation(s)
- Long Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Mengnan Zhou
- Department of Pathogenic Biology, School of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Hao Li
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Delin Liu
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Peng Liao
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Yao Zong
- Centre for Orthopaedic Research, Medical School, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Changqing Zhang
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Weiguo Zou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China.
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Junjie Gao
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
- Shanghai Sixth People's Hospital Fujian, No. 16, Luoshan Section, Jinguang Road, Luoshan Street, Jinjiang City, Quanzhou, Fujian, China.
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3
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Li G, Tang J, Huang J, Jiang Y, Fan Y, Wang X, Ren J. Genome-Wide Estimates of Runs of Homozygosity, Heterozygosity, and Genetic Load in Two Chinese Indigenous Goat Breeds. Front Genet 2022; 13:774196. [PMID: 35559012 PMCID: PMC9086400 DOI: 10.3389/fgene.2022.774196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
Runs of homozygosity (ROH) and heterozygosity (ROHet) are windows into population demographic history and adaptive evolution. Numerous studies have shown that deleterious mutations are enriched in the ROH of humans, pigs, cattle, and chickens. However, the relationship of deleterious variants to ROH and the pattern of ROHet in goats have been largely understudied. Here, 240 Guangfeng and Ganxi goats from Jiangxi Province, China, were genotyped using the Illumina GoatSNP50 BeadChip and genome-wide ROH, ROHet, and genetic load analyses were performed in the context of 32 global goat breeds. The classes with the highest percentage of ROH and ROHet were 0.5–2 Mb and 0.5–1 Mb, respectively. The results of inbreeding coefficients (based on SNP and ROH) and ROHet measurements showed that Guangfeng goats had higher genetic variability than most Chinese goats, while Ganxi goats had a high degree of inbreeding, even exceeding that of commercial goat breeds. Next, the predicted damaging homozygotes were more enriched in long ROHs, especially in Guangfeng goats. Therefore, we suggest that information on damaging alleles should also be incorporated into the design of breeding and conservation programs. A list of genes related to fecundity, growth, and environmental adaptation were identified in the ROH hotspots of two Jiangxi goats. A sense-related ROH hotspot (chromosome 12: 50.55–50.81 Mb) was shared across global goat breeds and may have undergone selection prior to goat domestication. Furthermore, an identical ROHet hotspot (chromosome 1: 132.21–132.54 Mb) containing two genes associated with embryonic development (STAG1 and PCCB) was detected in domestic goat breeds worldwide. Tajima’s D and BetaScan2 statistics indicated that this region may be caused by long-term balancing selection. These findings not only provide guidance for the design of conservation strategies for Jiangxi goat breeds but also enrich our understanding of the adaptive evolution of goats.
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Affiliation(s)
- Guixin Li
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Jianhong Tang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China.,Laboratory Animal Engineering Research Center of Ganzhou, Gannan Medical University, Ganzhou, China
| | - Jinyan Huang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yongchuang Jiang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yin Fan
- Department of Animal Science, Jiangxi Biotech Vocational College, Nanchang, China
| | - Xiaopeng Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Jun Ren
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
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Barrea L, Caprio M, Watanabe M, Cammarata G, Feraco A, Muscogiuri G, Verde L, Colao A, Savastano S. Could very low-calorie ketogenic diets turn off low grade inflammation in obesity? Emerging evidence. Crit Rev Food Sci Nutr 2022; 63:8320-8336. [PMID: 35373658 DOI: 10.1080/10408398.2022.2054935] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is an emerging non-communicable disease associated with chronic low-grade inflammation and oxidative stress, compounded by the development of many obesity-related diseases, such as cardiovascular disease, type 2 diabetes mellitus, and a range of cancers. Originally developed for the treatment of epilepsy in drug non-responder children, the ketogenic diet (KD) is being increasingly used in the treatment of many diseases, including obesity and obesity-related conditions. The KD is a dietary pattern characterized by high fat intake, moderate to low protein consumption, and very low carbohydrate intake (<50 g) that has proved to be an effective and weight-loss tool. In addition, it also appears to be a dietary intervention capable of improving the inflammatory state and oxidative stress in individuals with obesity by means of several mechanisms. The main activity of the KD has been linked to improving mitochondrial function and decreasing oxidative stress. β-hydroxybutyrate, the most studied ketone body, has been shown to reduce the production of reactive oxygen species, improving mitochondrial respiration. In addition, KDs exert anti-inflammatory activity through several mechanisms, e.g., by inhibiting activation of the nuclear factor kappa-light-chain-enhancer of activated B cells, and the inflammatory nucleotide-binding, leucine-rich-containing family, pyrin domain-containing-3, and inhibiting histone deacetylases. Given the rising interest in the topic, this review looks at the underlying anti-inflammatory and antioxidant mechanisms of KDs and their possible recruitment in the treatment of obesity and obesity-related disorders.
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Affiliation(s)
- Luigi Barrea
- Dipartimento di Scienze Umanistiche, Università Telematica Pegaso, Napoli, Italy
- Centro Italiano per la cura e il Benessere del paziente con Obesità (C.I.B.O), Department of Clinical Medicine and Surgery, Endocrinology Unit, University Medical School of Naples, Naples, Italy
| | - Massimiliano Caprio
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Roma, Rome, Italy
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, Rome, Italy
| | - Mikiko Watanabe
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, Rome, Italy
| | - Giuseppe Cammarata
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DiMI) and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Alessandra Feraco
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Roma, Rome, Italy
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Roma Open University, Rome, Italy
| | - Giovanna Muscogiuri
- Centro Italiano per la cura e il Benessere del paziente con Obesità (C.I.B.O), Department of Clinical Medicine and Surgery, Endocrinology Unit, University Medical School of Naples, Naples, Italy
- Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Naples, Italy
- Cattedra Unesco "Educazione alla salute e allo sviluppo sostenibile", University Federico II, Naples, Italy
| | - Ludovica Verde
- Centro Italiano per la cura e il Benessere del paziente con Obesità (C.I.B.O), Department of Clinical Medicine and Surgery, Endocrinology Unit, University Medical School of Naples, Naples, Italy
- Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Naples, Italy
| | - Annamaria Colao
- Centro Italiano per la cura e il Benessere del paziente con Obesità (C.I.B.O), Department of Clinical Medicine and Surgery, Endocrinology Unit, University Medical School of Naples, Naples, Italy
- Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Naples, Italy
- Cattedra Unesco "Educazione alla salute e allo sviluppo sostenibile", University Federico II, Naples, Italy
| | - Silvia Savastano
- Centro Italiano per la cura e il Benessere del paziente con Obesità (C.I.B.O), Department of Clinical Medicine and Surgery, Endocrinology Unit, University Medical School of Naples, Naples, Italy
- Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Naples, Italy
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Oxidative Phosphorylation Dysfunction Modifies the Cell Secretome. Int J Mol Sci 2020; 21:ijms21093374. [PMID: 32397676 PMCID: PMC7246988 DOI: 10.3390/ijms21093374] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/29/2020] [Accepted: 05/09/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial oxidative phosphorylation disorders are extremely heterogeneous conditions. Their clinical and genetic variability makes the identification of reliable and specific biomarkers very challenging. Until now, only a few studies have focused on the effect of a defective oxidative phosphorylation functioning on the cell’s secretome, although it could be a promising approach for the identification and pre-selection of potential circulating biomarkers for mitochondrial diseases. Here, we review the insights obtained from secretome studies with regard to oxidative phosphorylation dysfunction, and the biomarkers that appear, so far, to be promising to identify mitochondrial diseases. We propose two new biomarkers to be taken into account in future diagnostic trials.
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Santacatterina F, Torresano L, Núñez-Salgado A, Esparza-Molto PB, Olive M, Gallardo E, García-Arumi E, Blazquez A, González-Quintana A, Martín MA, Cuezva JM. Different mitochondrial genetic defects exhibit the same protein signature of metabolism in skeletal muscle of PEO and MELAS patients: A role for oxidative stress. Free Radic Biol Med 2018; 126:235-248. [PMID: 30138712 DOI: 10.1016/j.freeradbiomed.2018.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/15/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022]
Abstract
A major challenge in mitochondrial diseases (MDs) is the identification of biomarkers that could inform of the mechanisms involved in the phenotypic expression of genetic defects. Herein, we have investigated the protein signature of metabolism and of the antioxidant response in muscle biopsies of clinically and genetically diagnosed patients with Progressive External Ophthalmoplegia due to single large-scale (PEO-sD) or multiple (PEO-mD) deletions of mtDNA and Mitochondrial Encephalopathy Lactic Acidosis and Stroke-like episode (MELAS) syndrome, and healthy donors. A high-throughput immunoassay technique that quantitates the expression of relevant proteins of glycolysis, glycogenolysis, pentose phosphate pathway, oxidative phosphorylation, pyruvate and fatty acid oxidation, tricarboxylic acid cycle and the antioxidant response in two large independent and retrospectively collected cohorts of PEO-sD, PEO-mD and MELAS patients revealed that despite the heterogeneity of the genetic alterations, the three MDs showed the same metabolic signatures in both cohorts of patients, which were highly divergent from those of healthy individuals. Linear Discriminant Analysis and Support Vector Machine classifier provided a minimum of four biomarkers to discriminate healthy from pathological samples. Regardless of the induction of a large number of enzymes involved in ameliorating oxidative stress, the down-regulation of mitochondrial superoxide dismutase (SOD2) and catalase expression favored the accumulation of oxidative damage in patients' proteins. Down-regulation of SOD2 and catalase expression in MD patients is not due to relevant changes in the availability of their mRNAs, suggesting that oxidative stress regulates the expression of the two enzymes post-transcriptionally. We suggest that SOD2 and catalase could provide specific targets to improve the detoxification of reactive oxygen species that affects muscle proteins in these patients.
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Affiliation(s)
- Fulvio Santacatterina
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain
| | - Laura Torresano
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain
| | - Alfonso Núñez-Salgado
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Spain
| | - Pau B Esparza-Molto
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain
| | - Montse Olive
- Servicio de Anatomía Patológica, Unidad Patología Neuromuscular, IDIBELL-Hospital Universitario de Bellvitge, Spain
| | - Eduard Gallardo
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Elena García-Arumi
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Laboratorio de Patología Mitocondrial y Neuromuscular, Área de Genética Clínica y Molecular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Alberto Blazquez
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain; Laboratorio de Enfermedades Mitocondriales y Neuromusculares, Hospital Universitario, 12 de Octubre, Madrid, Spain
| | - Adrián González-Quintana
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain; Laboratorio de Enfermedades Mitocondriales y Neuromusculares, Hospital Universitario, 12 de Octubre, Madrid, Spain
| | - Miguel A Martín
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain; Laboratorio de Enfermedades Mitocondriales y Neuromusculares, Hospital Universitario, 12 de Octubre, Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Spain; Instituto de Investigación Hospital, 12 de Octubre (i+12), Madrid, Spain.
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Lv J, Bhatia M, Wang X. Roles of Mitochondrial DNA in Energy Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1038:71-83. [PMID: 29178070 DOI: 10.1007/978-981-10-6674-0_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Mitochondria are independent double-membrane organelles responsible for energy production, specifically by completing oxidative phosphorylation. Mitochondria are essential to regulate energy metabolism, signaling pathways, and cell death. Mitochondrial DNA (mtDNA) can be altered by metabolic disorders, oxidative stress, or inflammation in the progression and development of various diseases. In this chapter, we overview the role of mtDNA in energy metabolism and the diseases that are associated with mtDNA abnormality, with a special focus on the major factors which regulate the mechanism of mtDNA in metabolism.
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Affiliation(s)
- Jiapei Lv
- Zhongshan Hospital Institute of Fudan University, Shanghai Medical School, Shanghai, China
| | - Madhav Bhatia
- Department of Pathology, University of Otago, Wellington, New Zealand
| | - Xiangdong Wang
- Zhongshan Hospital Institute of Clinical Science, Fudan University, Shanghai Medical College, Shanghai, China.
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Llobet L, Bayona-Bafaluy MP, Pacheu-Grau D, Torres-Pérez E, Arbones-Mainar JM, Navarro MÁ, Gómez-Díaz C, Montoya J, López-Gallardo E, Ruiz-Pesini E. Pharmacologic concentrations of linezolid modify oxidative phosphorylation function and adipocyte secretome. Redox Biol 2017; 13:244-254. [PMID: 28600981 PMCID: PMC5466587 DOI: 10.1016/j.redox.2017.05.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 11/16/2022] Open
Abstract
The oxidative phosphorylation system is important for adipocyte differentiation. Therefore, xenobiotics inhibitors of the oxidative phosphorylation system could affect adipocyte differentiation and adipokine secretion. As adipokines impact the overall health status, these xenobiotics may have wide effects on human health. Some of these xenobiotics are widely used therapeutic drugs, such as ribosomal antibiotics. Because of its similarity to the bacterial one, mitochondrial translation system is an off-target for these compounds. To study the influence of the ribosomal antibiotic linezolid on adipokine production, we analyzed its effects on adipocyte secretome. Linezolid, at therapeutic concentrations, modifies the levels of apolipoprotein E and several adipokines and proteins related with the extracellular matrix. This antibiotic also alters the global methylation status of human adipose tissue-derived stem cells and, therefore, its effects are not limited to the exposure period. Besides their consequences on other tissues, xenobiotics acting on the adipocyte oxidative phosphorylation system alter apolipoprotein E and adipokine production, secondarily contributing to their systemic effects. Linezolid decreases oxidative phosphorylation system capacity. Linezolid reduces adipocyte differentiation from human adipose-derived stem cells. Linezolid modifies APOE, adipokine and extracellular matrix proteins levels. Linezolid changes DNA methylation of human adipose tissue-derived stem cells. Xenobiotics, acting on adipocyte oxidative phosphorylation, affect human health.
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Affiliation(s)
- Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain.
| | - M Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain.
| | - David Pacheu-Grau
- Department of Cellular Biochemistry, University Medical Center, Humboldtalle 23, 37073 Göttingen, Germany.
| | - Elena Torres-Pérez
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Unidad de Investigación Traslacional, Instituto Aragones de Ciencias de la Salud (IACS), Hospital Universitario Miguel Servet, Paseo de Isabel la Católica 1-3, 50009 Zaragoza, Spain.
| | - José M Arbones-Mainar
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Unidad de Investigación Traslacional, Instituto Aragones de Ciencias de la Salud (IACS), Hospital Universitario Miguel Servet, Paseo de Isabel la Católica 1-3, 50009 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red Fisiopatología de la Obesidad y Nutrición (CIBERObn), Hospital Universitario Miguel Servet, Paseo de Isabel la Católica 1-3, 50009 Zaragoza, Spain.
| | - M Ángeles Navarro
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red Fisiopatología de la Obesidad y Nutrición (CIBERObn), Hospital Universitario Miguel Servet, Paseo de Isabel la Católica 1-3, 50009 Zaragoza, Spain.
| | - Covadonga Gómez-Díaz
- Servicio de Otorrinolaringología, Hospital Universitario Miguel Servet, Paseo de Isabel la Católica 1-3, 50009 Zaragoza, Spain.
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain.
| | - Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain.
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; Fundación ARAID, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain.
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9
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Wang L. Mitochondrial purine and pyrimidine metabolism and beyond. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 35:578-594. [PMID: 27906631 DOI: 10.1080/15257770.2015.1125001] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Carefully balanced deoxynucleoside triphosphate (dNTP) pools are essential for both nuclear and mitochondrial genome replication and repair. Two synthetic pathways operate in cells to produce dNTPs, e.g., the de novo and the salvage pathways. The key regulatory enzymes for de novo synthesis are ribonucleotide reductase (RNR) and thymidylate synthase (TS), and this process is considered to be cytosolic. The salvage pathway operates both in the cytosol (TK1 and dCK) and the mitochondria (TK2 and dGK). Mitochondrial dNTP pools are separated from the cytosolic ones owing to the double membrane structure of the mitochondria, and are formed by the salvage enzymes TK2 and dGK together with NMPKs and NDPK in postmitotic tissues, while in proliferating cells the mitochondrial dNTPs are mainly imported from the cytosol produced by the cytosolic pathways. Imbalanced mitochondrial dNTP pools lead to mtDNA depletion and/or deletions resulting in serious mitochondrial diseases. The mtDNA depletion syndrome is caused by deficiencies not only in enzymes in dNTP synthesis (TK2, dGK, p53R2, and TP) and mtDNA replication (mtDNA polymerase and twinkle helicase), but also in enzymes in other metabolic pathways such as SUCLA2 and SUCLG1, ABAT and MPV17. Basic questions are why defects in these enzymes affect dNTP synthesis and how important is mitochondrial nucleotide synthesis in the whole cell/organism perspective? This review will focus on recent studies on purine and pyrimidine metabolism, which have revealed several important links that connect mitochondrial nucleotide metabolism with amino acids, glucose, and fatty acid metabolism.
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Affiliation(s)
- Liya Wang
- a Department of Anatomy, Physiology and Biochemistry , Swedish University of Agricultural Sciences , Uppsala , Sweden
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10
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Gao C, McDowell IC, Zhao S, Brown CD, Engelhardt BE. Context Specific and Differential Gene Co-expression Networks via Bayesian Biclustering. PLoS Comput Biol 2016; 12:e1004791. [PMID: 27467526 PMCID: PMC4965098 DOI: 10.1371/journal.pcbi.1004791] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 02/03/2016] [Indexed: 01/15/2023] Open
Abstract
Identifying latent structure in high-dimensional genomic data is essential for exploring biological processes. Here, we consider recovering gene co-expression networks from gene expression data, where each network encodes relationships between genes that are co-regulated by shared biological mechanisms. To do this, we develop a Bayesian statistical model for biclustering to infer subsets of co-regulated genes that covary in all of the samples or in only a subset of the samples. Our biclustering method, BicMix, allows overcomplete representations of the data, computational tractability, and joint modeling of unknown confounders and biological signals. Compared with related biclustering methods, BicMix recovers latent structure with higher precision across diverse simulation scenarios as compared to state-of-the-art biclustering methods. Further, we develop a principled method to recover context specific gene co-expression networks from the estimated sparse biclustering matrices. We apply BicMix to breast cancer gene expression data and to gene expression data from a cardiovascular study cohort, and we recover gene co-expression networks that are differential across ER+ and ER- samples and across male and female samples. We apply BicMix to the Genotype-Tissue Expression (GTEx) pilot data, and we find tissue specific gene networks. We validate these findings by using our tissue specific networks to identify trans-eQTLs specific to one of four primary tissues.
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Affiliation(s)
- Chuan Gao
- Department of Statistical Science, Duke University, Durham, North Carolina, United States of America
| | - Ian C. McDowell
- Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina, United States of America
| | - Shiwen Zhao
- Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina, United States of America
| | - Christopher D. Brown
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Barbara E. Engelhardt
- Department of Computer Science, Center for Statistics and Machine Learning, Princeton University, Princeton, New Jersey, United States of America
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11
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Llobet L, Toivonen JM, Montoya J, Ruiz-Pesini E, López-Gallardo E. Xenobiotics that affect oxidative phosphorylation alter differentiation of human adipose-derived stem cells at concentrations that are found in human blood. Dis Model Mech 2015; 8:1441-55. [PMID: 26398948 PMCID: PMC4631789 DOI: 10.1242/dmm.021774] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/03/2015] [Indexed: 12/17/2022] Open
Abstract
Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture or other human activities affect oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, such as ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. By contrast, the environmental chemical pollutant tributyltin chloride, which inhibits the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as postulated by the obesogen hypothesis. Summary: Some medical drugs and environmental chemical pollutants acting on the oxidative phosphorylation system can alter adipocyte differentiation and adipogenesis and, thus, have important consequences for human health.
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Affiliation(s)
- Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013-Zaragoza, Spain Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, 50013-Zaragoza, Spain CIBER de Enfermedades Raras (CIBERER), Universidad de Zaragoza, 50013-Zaragoza, Spain
| | - Janne M Toivonen
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013-Zaragoza, Spain Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, 50013-Zaragoza, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013-Zaragoza, Spain Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, 50013-Zaragoza, Spain CIBER de Enfermedades Raras (CIBERER), Universidad de Zaragoza, 50013-Zaragoza, Spain
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013-Zaragoza, Spain Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, 50013-Zaragoza, Spain CIBER de Enfermedades Raras (CIBERER), Universidad de Zaragoza, 50013-Zaragoza, Spain Fundación ARAID, Universidad de Zaragoza, 50013-Zaragoza, Spain
| | - Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013-Zaragoza, Spain Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, 50013-Zaragoza, Spain CIBER de Enfermedades Raras (CIBERER), Universidad de Zaragoza, 50013-Zaragoza, Spain
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12
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Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
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Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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Vernochet C, Damilano F, Mourier A, Bezy O, Mori MA, Smyth G, Rosenzweig A, Larsson NG, Kahn CR. Adipose tissue mitochondrial dysfunction triggers a lipodystrophic syndrome with insulin resistance, hepatosteatosis, and cardiovascular complications. FASEB J 2014; 28:4408-19. [PMID: 25005176 PMCID: PMC4202105 DOI: 10.1096/fj.14-253971] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/16/2014] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction in adipose tissue occurs in obesity, type 2 diabetes, and some forms of lipodystrophy, but whether this dysfunction contributes to or is the result of these disorders is unknown. To investigate the physiological consequences of severe mitochondrial impairment in adipose tissue, we generated mice deficient in mitochondrial transcription factor A (TFAM) in adipocytes by using mice carrying adiponectin-Cre and TFAM floxed alleles. These adiponectin TFAM-knockout (adipo-TFAM-KO) mice had a 75-81% reduction in TFAM in the subcutaneous and intra-abdominal white adipose tissue (WAT) and interscapular brown adipose tissue (BAT), causing decreased expression and enzymatic activity of proteins in complexes I, III, and IV of the electron transport chain (ETC). This mitochondrial dysfunction led to adipocyte death and inflammation in WAT and a whitening of BAT. As a result, adipo-TFAM-KO mice were resistant to weight gain, but exhibited insulin resistance on both normal chow and high-fat diets. These lipodystrophic mice also developed hypertension, cardiac hypertrophy, and cardiac dysfunction. Thus, isolated mitochondrial dysfunction in adipose tissue can lead a syndrome of lipodystrophy with metabolic syndrome and cardiovascular complications.
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Affiliation(s)
- Cecile Vernochet
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Federico Damilano
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA; Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; and
| | - Arnaud Mourier
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Olivier Bezy
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcelo A Mori
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Graham Smyth
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Anthony Rosenzweig
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA; Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; and
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA;
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14
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Koczor CA, Torres RA, Fields EJ, Boyd A, He S, Patel N, Lee EK, Samarel AM, Lewis W. Thymidine kinase and mtDNA depletion in human cardiomyopathy: epigenetic and translational evidence for energy starvation. Physiol Genomics 2013; 45:590-6. [PMID: 23695887 DOI: 10.1152/physiolgenomics.00014.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
This study addresses how depletion of human cardiac left ventricle (LV) mitochondrial DNA (mtDNA) and epigenetic nuclear DNA methylation promote cardiac dysfunction in human dilated cardiomyopathy (DCM) through regulation of pyrimidine nucleotide kinases. Samples of DCM LV and right ventricle (n = 18) were obtained fresh at heart transplant surgery. Parallel samples from nonfailing (NF) controls (n = 12) were from donor hearts found unsuitable for clinical use. We analyzed abundance of mtDNA and nuclear DNA (nDNA) using qPCR. LV mtDNA was depleted in DCM (50%, P < 0.05 each) compared with NF. No detectable change in RV mtDNA abundance occurred. DNA methylation and gene expression were determined using microarray analysis (GEO accession number: GSE43435). Fifty-seven gene promoters exhibited DNA hypermethylation or hypomethylation in DCM LVs. Among those, cytosolic thymidine kinase 1 (TK1) was hypermethylated. Expression arrays revealed decreased abundance of the TK1 mRNA transcript with no change in transcripts for other relevant thymidine metabolism enzymes. Quantitative immunoblots confirmed decreased TK1 polypeptide steady state abundance. TK1 activity remained unchanged in DCM samples while mitochondrial thymidine kinase (TK2) activity was significantly reduced. Compensatory TK activity was found in cardiac myocytes in the DCM LV. Diminished TK2 activity is mechanistically important to reduced mtDNA abundance and identified in DCM LV samples here. Epigenetic and genetic changes result in changes in mtDNA and in nucleotide substrates for mtDNA replication and underpin energy starvation in DCM.
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Affiliation(s)
- Christopher A Koczor
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia, USA
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15
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Zhou X, Kannisto K, Curbo S, von Döbeln U, Hultenby K, Isetun S, Gåfvels M, Karlsson A. Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation. PLoS One 2013; 8:e58843. [PMID: 23505564 PMCID: PMC3591375 DOI: 10.1371/journal.pone.0058843] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/07/2013] [Indexed: 02/06/2023] Open
Abstract
Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2−/−) that progressively loses its mtDNA. The TK2−/− mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2−/− mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2−/− mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2−/− mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2−/− mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.
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Affiliation(s)
- Xiaoshan Zhou
- Division of Clinical Microbiology F-68, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
| | - Kristina Kannisto
- Division of Clinical Chemistry, C1-72, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
| | - Sophie Curbo
- Division of Clinical Microbiology F-68, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
- * E-mail:
| | - Ulrika von Döbeln
- Division of Metabolic Diseases, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
| | - Kjell Hultenby
- Division of Clinical Research Center, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
| | - Sindra Isetun
- Division of Metabolic Diseases, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
| | - Mats Gåfvels
- Division of Clinical Chemistry, C1-72, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
- Division of Clinical Chemistry, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Anna Karlsson
- Division of Clinical Microbiology F-68, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, Huddinge, Sweden
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Gene expression deregulation in postnatal skeletal muscle of TK2 deficient mice reveals a lower pool of proliferating myogenic progenitor cells. PLoS One 2013; 8:e53698. [PMID: 23341978 PMCID: PMC3544874 DOI: 10.1371/journal.pone.0053698] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 12/03/2012] [Indexed: 01/07/2023] Open
Abstract
Loss of thymidine kinase 2 (TK2) causes a heterogeneous myopathic form of mitochondrial DNA (mtDNA) depletion syndrome (MDS) in humans that predominantly affects skeletal muscle tissue. In mice, TK2 deficiency also affects several tissues in addition to skeletal muscle, including brain, heart, adipose tissue, kidneys and causes death about 3 weeks after birth. We analysed skeletal muscle and heart muscle tissues of Tk2 knockout mice at postnatal development phase and observed that TK2 deficient pups grew slower and their skeletal muscles appeared significantly underdeveloped, whereas heart was close to normal in size. Both tissues showed mtDNA depletion and mitochondria with altered ultrastructure, as revealed by transmission electron microscopy. Gene expression microarray analysis showed a strong down-regulation of genes involved in cell cycle and cell proliferation in both tissues, suggesting a lower pool of undifferentiated proliferating cells. Analysis of isolated primary myoblasts from Tk2 knockout mice showed slow proliferation, less ability to differentiate and signs of premature senescence, even in absence of mtDNA depletion. Our data demonstrate that TK2 deficiency disturbs myogenic progenitor cells function in postnatal skeletal muscle and we propose this as one of the causes of underdeveloped phenotype and myopathic characteristic of the TK2 deficient mice, in addition to the progressive mtDNA depletion, mitochondrial damage and respiratory chain deficiency in post-mitotic differentiated tissue.
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Pref-1 in brown adipose tissue: specific involvement in brown adipocyte differentiation and regulatory role of C/EBPδ. Biochem J 2012; 443:799-810. [PMID: 22324440 DOI: 10.1042/bj20111714] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pref-1 (pre-adipocyte factor-1) is known to play a central role in regulating white adipocyte differentiation, but the role of Pref-1 in BAT (brown adipose tissue) has not been analysed. In the present study we found that Pref-1 expression is high in fetal BAT and declines progressively after birth. However, Pref-1-null mice showed unaltered fetal development of BAT, but exhibited signs of over-activation of BAT thermogenesis in the post-natal period. In C/EBP (CCAAT/enhancer-binding protein) α-null mice, a rodent model of impaired fetal BAT differentiation, Pref-1 was dramatically overexpressed, in association with reduced expression of the Ucp1 (uncoupling protein 1) gene, a BAT-specific marker of thermogenic differentiation. In brown adipocyte cell culture models, Pref-1 was mostly expressed in pre-adipocytes and declined with brown adipocyte differentiation. The transcription factor C/EBPδ activated the Pref-1 gene transcription in brown adipocytes, through binding to the proximal promoter region. Accordingly, siRNA (small interfering RNA)-induced C/EBPδ knockdown led to reduced Pref-1 gene expression. This effect is consistent with the observed overexpression of C/EBPδ in C/EBPα-null BAT and high expression of C/EBPδ in brown pre-adipocytes. Dexamethasone treatment of brown pre-adipocytes suppressed Pref-1 down-regulation occurring throughout the brown adipocyte differentiation process, increased the expression of C/EBPδ and strongly impaired expression of the thermogenic markers UCP1 and PGC-1α [PPARγ (peroxisome-proliferator-activated receptor γ) co-activator-α]. However, it did not alter normal fat accumulation or expression of non-BAT-specific genes. Collectively, these results specifically implicate Pref-1 in controlling the thermogenic gene expression program in BAT, and identify C/EBPδ as a novel transcriptional regulator of Pref-1 gene expression that may be related to the specific role of glucocorticoids in BAT differentiation.
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