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Jokinen R, Pirnes-Karhu S, Pietiläinen KH, Pirinen E. Adipose tissue NAD +-homeostasis, sirtuins and poly(ADP-ribose) polymerases -important players in mitochondrial metabolism and metabolic health. Redox Biol 2017; 12:246-263. [PMID: 28279944 PMCID: PMC5343002 DOI: 10.1016/j.redox.2017.02.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/13/2017] [Indexed: 12/14/2022] Open
Abstract
Obesity, a chronic state of energy overload, is characterized by adipose tissue dysfunction that is considered to be the major driver for obesity associated metabolic complications. The reasons for adipose tissue dysfunction are incompletely understood, but one potential contributing factor is adipose tissue mitochondrial dysfunction. Derangements of adipose tissue mitochondrial biogenesis and pathways associate with obesity and metabolic diseases. Mitochondria are central organelles in energy metabolism through their role in energy derivation through catabolic oxidative reactions. The mitochondrial processes are dependent on the proper NAD+/NADH redox balance and NAD+ is essential for reactions catalyzed by the key regulators of mitochondrial metabolism, sirtuins (SIRTs) and poly(ADP-ribose) polymerases (PARPs). Notably, obesity is associated with disturbed adipose tissue NAD+ homeostasis and the balance of SIRT and PARP activities. In this review we aim to summarize existing literature on the maintenance of intracellular NAD+ pools and the function of SIRTs and PARPs in adipose tissue during normal and obese conditions, with the purpose of comprehending their potential role in mitochondrial derangements and obesity associated metabolic complications. Understanding the molecular mechanisms that are the root cause of the adipose tissue mitochondrial derangements is crucial for developing new effective strategies to reverse obesity associated metabolic complications.
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Affiliation(s)
- Riikka Jokinen
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, Biomedicum Helsinki, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Sini Pirnes-Karhu
- Molecular Neurology, Research Programs Unit, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Kirsi H Pietiläinen
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, Biomedicum Helsinki, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland; Endocrinology, Abdominal Center, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; FIMM, Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland
| | - Eija Pirinen
- Molecular Neurology, Research Programs Unit, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland.
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Bartolome F, Antequera D, Tavares E, Pascual C, Maldonado R, Camins A, Carro E. Obesity and neuroinflammatory phenotype in mice lacking endothelial megalin. J Neuroinflammation 2017; 14:26. [PMID: 28143489 PMCID: PMC5282716 DOI: 10.1186/s12974-017-0800-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The multiligand receptor megalin controls the brain uptake of a number of ligands, including insulin and leptin. Despite the role of megalin in the transport of these metabolically relevant hormones, the role of megalin at the blood-brain-barrier (BBB) has not yet been explored in the context of metabolic regulation. METHODS Here we investigate the role of brain endothelial megalin in energy metabolism and leptin signaling using an endothelial cell-specific megalin deficient (EMD) mouse model. RESULTS We found megalin is important to protect mice from developing obesity and metabolic syndrome when mice are fed a normal chow diet. EMD mice developed neuroinflammation, by triggering several pro-inflammatory cytokines, displayed reduced neurogenesis and mitochondrial deregulation. CONCLUSIONS These results implicate brain endothelial megalin expression in obesity-related metabolic changes through the leptin signaling pathway proposing a potential link between obesity and neurodegeneration.
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Affiliation(s)
- Fernando Bartolome
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i + 12), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Desiree Antequera
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i + 12), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Eva Tavares
- Clinical and Experimental Pharmacology Research Unit, Valme University Hospital, Seville, Spain
| | - Consuelo Pascual
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i + 12), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Rosario Maldonado
- Clinical and Experimental Pharmacology Research Unit, Valme University Hospital, Seville, Spain
| | - Antoni Camins
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain.,Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Eva Carro
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i + 12), Madrid, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain.
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Heinonen S, Muniandy M, Buzkova J, Mardinoglu A, Rodríguez A, Frühbeck G, Hakkarainen A, Lundbom J, Lundbom N, Kaprio J, Rissanen A, Pietiläinen KH. Mitochondria-related transcriptional signature is downregulated in adipocytes in obesity: a study of young healthy MZ twins. Diabetologia 2017; 60:169-181. [PMID: 27734103 DOI: 10.1007/s00125-016-4121-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/09/2016] [Indexed: 01/04/2023]
Abstract
AIMS/HYPOTHESIS Low mitochondrial activity in adipose tissue is suggested to be an underlying factor in obesity and its metabolic complications. We aimed to find out whether mitochondrial measures are downregulated in obesity also in isolated adipocytes. METHODS We studied young adult monozygotic (MZ) twin pairs discordant (n = 14, intrapair difference ΔBMI ≥ 3 kg/m2) and concordant (n = 5, ΔBMI < 3 kg/m2) for BMI, identified from ten birth cohorts of 22- to 36-year-old Finnish twins. Abdominal body fat distribution (MRI), liver fat content (magnetic resonance spectroscopy), insulin sensitivity (OGTT), high-sensitivity C-reactive protein, serum lipids and adipokines were measured. Subcutaneous abdominal adipose tissue biopsies were obtained to analyse the transcriptomics patterns of the isolated adipocytes as well as of the whole adipose tissue. Mitochondrial DNA transcript levels in adipocytes were measured by quantitative real-time PCR. Western blots of oxidative phosphorylation (OXPHOS) protein levels in adipocytes were performed in obese and lean unrelated individuals. RESULTS The heavier (BMI 29.9 ± 1.0 kg/m2) co-twins of the discordant twin pairs had more subcutaneous, intra-abdominal and liver fat and were more insulin resistant (p < 0.01 for all measures) than the lighter (24.1 ± 0.9 kg/m2) co-twins. Altogether, 2538 genes in adipocytes and 2135 in adipose tissue were significantly differentially expressed (nominal p < 0.05) between the co-twins. Pathway analysis of these transcripts in both isolated adipocytes and adipose tissue revealed that the heavier co-twins displayed reduced expression of genes relating to mitochondrial pathways, a result that was replicated when analysing the pathways behind the most consistently downregulated genes in the heavier co-twins (in at least 12 out of 14 pairs). Consistently upregulated genes in adipocytes were related to inflammation. We confirmed that mitochondrial DNA transcript levels (12S RNA, 16S RNA, COX1, ND5, CYTB), expression of mitochondrial ribosomal protein transcripts and a major mitochondrial regulator PGC-1α (also known as PPARGC1A) were reduced in the heavier co-twins' adipocytes (p < 0.05). OXPHOS protein levels of complexes I and III in adipocytes were lower in obese than in lean individuals. CONCLUSIONS/INTERPRETATION Subcutaneous abdominal adipocytes in obesity show global expressional downregulation of oxidative pathways, mitochondrial transcripts and OXPHOS protein levels and upregulation of inflammatory pathways. DATA AVAILABILITY The datasets analysed and generated during the current study are available in the figshare repository, https://dx.doi.org/10.6084/m9.figshare.3806286.v1.
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Affiliation(s)
- Sini Heinonen
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, University of Helsinki, Biomedicum Helsinki, C424b, P.O. Box 63, Haartmaninkatu 8, 00014, Helsinki, Finland
| | - Maheswary Muniandy
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, University of Helsinki, Biomedicum Helsinki, C424b, P.O. Box 63, Haartmaninkatu 8, 00014, Helsinki, Finland
| | - Jana Buzkova
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Adil Mardinoglu
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Amaia Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain
- CIBEROBN, Instituto de Salud Carlos III, Pamplona, Spain
| | - Gema Frühbeck
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain
- CIBEROBN, Instituto de Salud Carlos III, Pamplona, Spain
| | - Antti Hakkarainen
- HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Jesper Lundbom
- HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany
| | - Nina Lundbom
- HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Jaakko Kaprio
- FIMM, Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland
- Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki, Finland
- National Institute for Health and Welfare, Department of Health, Helsinki, Finland
| | - Aila Rissanen
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, University of Helsinki, Biomedicum Helsinki, C424b, P.O. Box 63, Haartmaninkatu 8, 00014, Helsinki, Finland
- Department of Psychiatry, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Kirsi H Pietiläinen
- Obesity Research Unit, Research Programs Unit, Diabetes and Obesity, University of Helsinki, Biomedicum Helsinki, C424b, P.O. Box 63, Haartmaninkatu 8, 00014, Helsinki, Finland.
- FIMM, Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland.
- Endocrinology, Abdominal Center, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland.
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