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Martínez-Redondo V, Pettersson AT, Ruas JL. The hitchhiker's guide to PGC-1α isoform structure and biological functions. Diabetologia 2015; 58:1969-77. [PMID: 26109214 DOI: 10.1007/s00125-015-3671-z] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/03/2015] [Indexed: 12/16/2022]
Abstract
Proteins of the peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1 (PGC-1) family of transcriptional coactivators coordinate physiological adaptations in many tissues, usually in response to demands for higher nutrient and energy supply. Of the founding members of the family, PGC-1α (also known as PPARGC1A) is the most highly regulated gene, using multiple promoters and alternative splicing to produce a growing number of coactivator variants. PGC-1α promoters are selectively active in distinct tissues in response to specific stimuli. To date, more than ten novel PGC-1α isoforms have been reported to be expressed from a novel promoter (PGC-1α-b, PGC-1α-c), to undergo alternative splicing (NT-PGC-1α) or both (PGC-1α2, PGC-1α3, PGC-1α4). The resulting proteins display differential regulation and tissue distribution and, most importantly, exert specific biological functions. In this review we discuss the structural and functional characteristics of the novel PGC-1α isoforms, aiming to provide an integrative view of this constantly expanding system of transcriptional coactivators.
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Affiliation(s)
- Vicente Martínez-Redondo
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177, Stockholm, Sweden
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52
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Lipovich L, Hou ZC, Jia H, Sinkler C, McGowen M, Sterner KN, Weckle A, Sugalski AB, Pipes L, Gatti DL, Mason CE, Sherwood CC, Hof PR, Kuzawa CW, Grossman LI, Goodman M, Wildman DE. High-throughput RNA sequencing reveals structural differences of orthologous brain-expressed genes between western lowland gorillas and humans. J Comp Neurol 2015; 524:288-308. [PMID: 26132897 DOI: 10.1002/cne.23843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/20/2015] [Accepted: 06/23/2015] [Indexed: 12/22/2022]
Abstract
The human brain and human cognitive abilities are strikingly different from those of other great apes despite relatively modest genome sequence divergence. However, little is presently known about the interspecies divergence in gene structure and transcription that might contribute to these phenotypic differences. To date, most comparative studies of gene structure in the brain have examined humans, chimpanzees, and macaque monkeys. To add to this body of knowledge, we analyze here the brain transcriptome of the western lowland gorilla (Gorilla gorilla gorilla), an African great ape species that is phylogenetically closely related to humans, but with a brain that is approximately one-third the size. Manual transcriptome curation from a sample of the planum temporale region of the neocortex revealed 12 protein-coding genes and one noncoding-RNA gene with exons in the gorilla unmatched by public transcriptome data from the orthologous human loci. These interspecies gene structure differences accounted for a total of 134 amino acids in proteins found in the gorilla that were absent from protein products of the orthologous human genes. Proteins varying in structure between human and gorilla were involved in immunity and energy metabolism, suggesting their relevance to phenotypic differences. This gorilla neocortical transcriptome comprises an empirical, not homology- or prediction-driven, resource for orthologous gene comparisons between human and gorilla. These findings provide a unique repository of the sequences and structures of thousands of genes transcribed in the gorilla brain, pointing to candidate genes that may contribute to the traits distinguishing humans from other closely related great apes.
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Affiliation(s)
- Leonard Lipovich
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, 48201
| | - Zhuo-Cheng Hou
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,Department of Animal Genetics, China Agricultural University, Beijing, China
| | - Hui Jia
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201
| | - Christopher Sinkler
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201
| | - Michael McGowen
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
| | - Kirstin N Sterner
- Department of Anthropology, University of Oregon, Eugene, Oregon, 97403
| | - Amy Weckle
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, 61801.,Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois, 61801
| | - Amara B Sugalski
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201
| | - Lenore Pipes
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, 10021
| | - Domenico L Gatti
- Department of Biochemistry and Molecular Biology, School of Medicine, Wayne State University, Detroit, Michigan, 48201.,Cardiovascular Research Institute, School of Medicine, Wayne State University, Detroit, Michigan, 48201
| | - Christopher E Mason
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, 10021
| | - Chet C Sherwood
- Department of Anthropology and the Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, 20052
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, 10029.,New York Consortium in Evolutionary Primatology, New York, New York, 10024
| | | | - Lawrence I Grossman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201
| | - Morris Goodman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,Department of Anatomy and Cell Biology, School of Medicine, Wayne State University, Detroit, Michigan, 48201
| | - Derek E Wildman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, 48201.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, 61801.,Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois, 61801
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53
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Schwalm C, Jamart C, Benoit N, Naslain D, Prémont C, Prévet J, Van Thienen R, Deldicque L, Francaux M. Activation of autophagy in human skeletal muscle is dependent on exercise intensity and AMPK activation. FASEB J 2015; 29:3515-26. [DOI: 10.1096/fj.14-267187] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/27/2015] [Indexed: 12/21/2022]
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54
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Zamora M, Pardo R, Villena JA. Pharmacological induction of mitochondrial biogenesis as a therapeutic strategy for the treatment of type 2 diabetes. Biochem Pharmacol 2015. [PMID: 26212547 DOI: 10.1016/j.bcp.2015.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Defects in mitochondrial oxidative function have been associated with the onset of type 2 diabetes. Although the causal relationship between mitochondrial dysfunction and diabetes has not been fully established, numerous studies indicate that improved glucose homeostasis achieved via lifestyle interventions, such as exercise or calorie restriction, is tightly associated with increased mitochondrial biogenesis and oxidative function. Therefore, it is conceivable that potentiating mitochondrial biogenesis by pharmacological means could constitute an efficacious therapeutic strategy that would particularly benefit those diabetic patients who cannot adhere to comprehensive programs based on changes in lifestyle or that require a relatively rapid improvement in their diabetic status. In this review, we discuss several pharmacological targets and drugs that modulate mitochondrial biogenesis as well as their potential use as treatments for insulin resistance and diabetes.
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Affiliation(s)
- Mònica Zamora
- Cell Biology Group, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, CIBER on Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Rosario Pardo
- Laboratory of Metabolism and Obesity, Vall d'Hebron-Institut de Recerca, Universitat Autònoma de Barcelona, CIBER on Diabetes and Associated Metabolic Diseases (CIBERDEM), Barcelona, Spain
| | - Josep A Villena
- Laboratory of Metabolism and Obesity, Vall d'Hebron-Institut de Recerca, Universitat Autònoma de Barcelona, CIBER on Diabetes and Associated Metabolic Diseases (CIBERDEM), Barcelona, Spain.
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55
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Popov DV, Lysenko EA, Miller TF, Bachinin AV, Perfilov DV, Vinogradova OL. The effect of single aerobic exercise on the regulation of mitochondrial biogenesis in skeletal muscles of trained men: A time-course study. ACTA ACUST UNITED AC 2015. [DOI: 10.1134/s0362119715030123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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56
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Lochmann TL, Thomas RR, Bennett JP, Taylor SM. Epigenetic Modifications of the PGC-1α Promoter during Exercise Induced Expression in Mice. PLoS One 2015; 10:e0129647. [PMID: 26053857 PMCID: PMC4460005 DOI: 10.1371/journal.pone.0129647] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/12/2015] [Indexed: 11/18/2022] Open
Abstract
The transcriptional coactivator, PGC-1α, is known for its role in mitochondrial biogenesis. Although originally thought to exist as a single protein isoform, recent studies have identified additional promoters which produce multiple mRNA transcripts. One of these promoters (promoter B), approximately 13.7kb upstream of the canonical PGC-1α promoter (promoter A), yields alternative transcripts present at levels much lower than the canonical PGC-1α mRNA transcript. In skeletal muscle, exercise resulted in a substantial, rapid increase of mRNA of these alternative PGC-1α transcripts. Although the β2-adrenergic receptor was identified as a signaling pathway that activates transcription from PGC-1α promoter B, it is not yet known what molecular changes occur to facilitate PGC-1α promoter B activation following exercise. We sought to determine whether epigenetic modifications were involved in this exercise response in mouse skeletal muscle. We found that DNA hydroxymethylation correlated to increased basal mRNA levels from PGC-1α promoter A, but that DNA methylation appeared to play no role in the exercise-induced activation of PGC-1α promoter B. The level of the activating histone mark H3K4me3 increased with exercise 2–4 fold across PGC-1α promoter B, but remained unaltered past the canonical PGC-1α transcriptional start site. Together, these data show that epigenetic modifications partially explain exercise-induced changes in the skeletal muscle mRNA levels of PGC-1α isoforms.
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Affiliation(s)
- Timothy L. Lochmann
- Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ravindar R. Thomas
- Parkinson’s Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - James P. Bennett
- Parkinson’s Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Shirley M. Taylor
- Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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57
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Lally JSV, Ford RJ, Johar J, Crane JD, Kemp BE, Steinberg GR. Skeletal muscle AMPK is essential for the maintenance of FNDC5 expression. Physiol Rep 2015; 3:3/5/e12343. [PMID: 25948819 PMCID: PMC4463812 DOI: 10.14814/phy2.12343] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Fibronectin type III domain-containing protein 5 (FNDC5) expression is controlled by the transcriptional co-activator, peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC1α). FNDC5 expression has been shown to be increased in muscle in response to endurance exercise in some but not all studies, therefore a greater understanding of the mechanisms controlling this process are needed. The AMP-activated protein kinase (AMPK) is activated by exercise in an intensity dependent manner and is an important regulator of PGC1α activity; therefore, we explored the role of AMPK in the regulation of FNDC5 using AMPK β1β2 double muscle-null mice (AMPK DMKO), which lack skeletal muscle AMPK activity. We found that FNDC5 expression is dramatically reduced in resting muscles of AMPK DMKO mice compared to wild-type littermates. In wild-type mice, activating phosphorylation of AMPK was elevated immediately post contraction and was abolished in muscle from AMPK DMKO mice. In contrast, PGC1α was increased in both wild-type and AMPK DMKO mice 3 h post contraction but FNDC5 protein expression was not altered. Lastly, acute or chronic activation of AMPK with the pharmacological AMPK activator AICAR did not increase PGC1α or FNDC5 expression in muscle. These data indicate that skeletal muscle AMPK is required for the maintenance of basal FNDC5 expression.
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Affiliation(s)
- James S V Lally
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Rebecca J Ford
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Jasper Johar
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Justin D Crane
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Bruce E Kemp
- St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Fitzroy, Victoria, Australia
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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58
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Mille-Hamard L, Breuneval C, Rousseau AS, Grimaldi P, Billat VL. Transcriptional modulation of mitochondria biogenesis pathway at and above critical speed in mice. Mol Cell Biochem 2015; 405:223-32. [DOI: 10.1007/s11010-015-2413-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 04/18/2015] [Indexed: 01/08/2023]
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59
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Pugh JK, Faulkner SH, Jackson AP, King JA, Nimmo MA. Acute molecular responses to concurrent resistance and high-intensity interval exercise in untrained skeletal muscle. Physiol Rep 2015; 3:e12364. [PMID: 25902785 PMCID: PMC4425969 DOI: 10.14814/phy2.12364] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/04/2015] [Indexed: 01/17/2023] Open
Abstract
Concurrent training involving resistance and endurance exercise may augment the benefits of single-mode training for the purpose of improving health. However, muscle adaptations, associated with resistance exercise, may be blunted by a subsequent bout of endurance exercise, via molecular interference. High-intensity interval training (HIIT), generating similar adaptations to endurance exercise, may offer an alternative exercise mode to traditional endurance exercise. This study examined the influence of an acute HIIT session on the molecular responses following resistance exercise in untrained skeletal muscle. Ten male participants performed resistance exercise (4 × 8 leg extensions, 70% 1RM, (RE)) or RE followed by HIIT (10 × 1 min at 90% HRmax, (RE+HIIT)). Muscle biopsies were collected from the vastus lateralis before, 2 and 6 h post-RE to determine intramuscular protein phosphorylation and mRNA responses. Phosphorylation of Akt (Ser(473)) decreased at 6 h in both trials (P < 0.05). Phosphorylation of mTOR (Ser(2448)) was higher in RE+HIIT (P < 0.05). All PGC-1α mRNA variants increased at 2 h in RE+HIIT with PGC-1α and PGC-1α-ex1b remaining elevated at 6 h, whereas RE-induced increases at 2 and 6 h for PGC-1α-ex1b only (P < 0.05). Myostatin expression decreased at 2 and 6 h in both trials (P < 0.05). MuRF-1 was elevated in RE+HIIT versus RE at 2 and 6 h (P < 0.05). Atrogin-1 was lower at 2 h, with FOXO3A downregulated at 6 h (P < 0.05). These data do not support the existence of an acute interference effect on protein signaling and mRNA expression, and suggest that HIIT may be an alternative to endurance exercise when performed after resistance exercise in the same training session to optimize adaptations.
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Affiliation(s)
- Jamie K Pugh
- School of Sport Exercise and Health Sciences Loughborough University, Loughborough, UK
| | - Steve H Faulkner
- School of Sport Exercise and Health Sciences Loughborough University, Loughborough, UK
| | - Andrew P Jackson
- School of Sport Exercise and Health Sciences Loughborough University, Loughborough, UK
| | - James A King
- School of Sport Exercise and Health Sciences Loughborough University, Loughborough, UK
| | - Myra A Nimmo
- School of Sport Exercise and Health Sciences Loughborough University, Loughborough, UK College of Life and Environmental Sciences University of Birmingham, Birmingham, UK
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60
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Eschbach J, von Einem B, Müller K, Bayer H, Scheffold A, Morrison BE, Rudolph KL, Thal DR, Witting A, Weydt P, Otto M, Fauler M, Liss B, McLean PJ, Spada ARL, Ludolph AC, Weishaupt JH, Danzer KM. Mutual exacerbation of peroxisome proliferator-activated receptor γ coactivator 1α deregulation and α-synuclein oligomerization. Ann Neurol 2014; 77:15-32. [PMID: 25363075 DOI: 10.1002/ana.24294] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 09/29/2014] [Accepted: 10/05/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson disease (PD), with accumulating evidence that prefibrillar oligomers and protofibrils are the pathogenic species in PD and related synucleinopathies. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a key regulator of mitochondrial biogenesis and cellular energy metabolism, has recently been associated with the pathophysiology of PD. Despite extensive effort on studying the function of PGC-1α in mitochondria, no studies have addressed whether PGC-1α directly influences oligomerization of α-syn or whether α-syn oligomers impact PGC-1α expression. MATERIALS AND METHODS We tested whether pharmacological or genetic activation of PGC-1α or PGC-11α knockdown could modulate the oligomerization of α-syn in vitro by using an α-syn -fragment complementation assay. RESULTS In this study, we found that both PGC-1α reference gene (RG-PGC-1α) and the central nervous system (CNS)-specific PGC-1α (CNS-PGC-1α) are downregulated in human PD brain, in A30P α-syn transgenic animals, and in a cell culture model for α-syn oligomerization. Importantly, downregulation of both RG-PGC-1α and CNS-PGC-1α in cell culture or neurons from RG-PGC-1α-deficient mice leads to a strong induction of α-syn oligomerization and toxicity. In contrast, pharmacological activation or genetic overexpression of RG-PGC-1α reduced α-syn oligomerization and rescued α-syn-mediated toxicity. INTERPRETATION Based on our results, we propose that PGC-1α downregulation and α-syn oligomerization form a vicious circle, thereby influencing and/or potentiating each other. Our data indicate that restoration of PGC-1α is a promising approach for development of effective drugs for the treatment of PD and related synucleinopathies.
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Affiliation(s)
- Judith Eschbach
- Department of Neurology, Ulm University, Ulm, Germany; Inoviem Scientific, Strasbourg, France
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61
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Swerdlow RH. Bioenergetic medicine. Br J Pharmacol 2014; 171:1854-69. [PMID: 24004341 DOI: 10.1111/bph.12394] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 08/17/2013] [Accepted: 08/22/2013] [Indexed: 12/12/2022] Open
Abstract
Here we discuss a specific therapeutic strategy we call 'bioenergetic medicine'. Bioenergetic medicine refers to the manipulation of bioenergetic fluxes to positively affect health. Bioenergetic medicine approaches rely heavily on the law of mass action, and impact systems that monitor and respond to the manipulated flux. Since classically defined energy metabolism pathways intersect and intertwine, targeting one flux also tends to change other fluxes, which complicates treatment design. Such indirect effects, fortunately, are to some extent predictable, and from a therapeutic perspective may also be desirable. Bioenergetic medicine-based interventions already exist for some diseases, and because bioenergetic medicine interventions are presently feasible, new approaches to treat certain conditions, including some neurodegenerative conditions and cancers, are beginning to transition from the laboratory to the clinic.
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Affiliation(s)
- Russell H Swerdlow
- Departments of Neurology, Molecular and Integrative Physiology, Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, KS, USA; Alzheimer's Disease Center, University of Kansas Medical Center, Fairway, KS, USA
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Popov DV, Bachinin AV, Lysenko EA, Miller TF, Vinogradova OL. Exercise-induced expression of peroxisome proliferator-activated receptor γ coactivator-1α isoforms in skeletal muscle of endurance-trained males. J Physiol Sci 2014; 64:317-23. [PMID: 24907054 PMCID: PMC10718011 DOI: 10.1007/s12576-014-0321-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 05/20/2014] [Indexed: 12/13/2022]
Abstract
The aim of the present study was to investigate the effect of acute aerobic exercise on the expression of PGC-1α transcript variants in human skeletal muscle. Seven endurance-trained athletes performed a 90-min cycling test (62% of VO2max). At resting state, the levels of N-truncated (NT)-PGC-1α and PGC-1α exon 1a-derived transcripts were significantly higher (>20-fold; P<0.05) than those of PGC-1α exon 1b- and 1c-derived transcripts. Acute exercise did not change the PGC-1α exon 1a-derived expression level, but it did increase the expression level of NT-PGC-1α mRNAs 6-fold, and the expression levels of PGC-1α exon 1b- and 1c-derived mRNAs>200-fold (P<0.05). We conclude that NT-PGC-1α transcript expression in resting muscle and after acute moderate-intensity exercise constituted a significant share of total PGC-1α expression. The exercise led to a higher level of PGC-1α expression from alternative promoters (exon 1b- and 1c-derived mRNA) than from the canonical proximal promoter (exon 1a-derived mRNA).
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Affiliation(s)
- Daniil V Popov
- Institute of Biomedical Problems, Russian Academy of Sciences, 76A Khoroshevskoe Shosse, Moscow, 123007, Russia,
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63
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Effect of exercise intensity on isoform-specific expressions of NT-PGC-1 α mRNA in mouse skeletal muscle. BIOMED RESEARCH INTERNATIONAL 2014; 2014:402175. [PMID: 25136584 PMCID: PMC4106048 DOI: 10.1155/2014/402175] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/02/2014] [Accepted: 04/28/2014] [Indexed: 11/17/2022]
Abstract
PGC-1α is an inducible transcriptional coactivator that regulates mitochondrial biogenesis and cellular energy metabolism in skeletal muscle. Recent studies have identified two additional PGC-1α transcripts that are derived from an alternative exon 1 (exon 1b) and induced by exercise. Given that the PGC-1α gene also produces NT-PGC-1α transcript by alternative 3′ splicing between exon 6 and exon 7, we have investigated isoform-specific expression of NT-PGC-1α mRNA in mouse skeletal muscle during physical exercise with different intensities. We report here that NT-PGC-1α-a mRNA expression derived from a canonical exon 1 (exon 1a) is increased by high-intensity exercise and AMPK activator AICAR in mouse skeletal muscle but not altered by low- and medium-intensity exercise and β2-adrenergic receptor agonist clenbuterol. In contrast, the alternative exon 1b-driven NT-PGC-1α-b (PGC-1α4) and NT-PGC-1α-c are highly induced by low-, medium-, and high-intensity exercise, AICAR, and clenbuterol. Ectopic expression of NT-PGC-1α-a in C2C12 myotube cells upregulates myosin heavy chain (MHC I, MHC II a) and Glut4, which represent oxidative fibers, and promotes the expression of mitochondrial genes (Cyc1, COX5B, and ATP5B). In line with gene expression data, citrate synthase activity was significantly increased by NT-PGC-1α-a in C2C12 myotube cells. Our results indicate the regulatory role for NT-PGC-1α-a in mitochondrial biogenesis and adaptation of skeletal muscle to endurance exercise.
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64
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Abstract
Skeletal muscle is the largest organ in the body and contributes to innumerable aspects of organismal biology. Muscle dysfunction engenders numerous diseases, including diabetes, cachexia, and sarcopenia. At the same time, skeletal muscle is also the main engine of exercise, one of the most efficacious interventions for prevention and treatment of a wide variety of diseases. The transcriptional coactivator PGC-1α has emerged as a key driver of metabolic programming in skeletal muscle, both in health and in disease. We review here the many aspects of PGC-1α function in skeletal muscle, with a focus on recent developments.
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Affiliation(s)
- Mun Chun Chan
- Cardiovascular Institute and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center and Harvard Medical School
| | - Zolt Arany
- Cardiovascular Institute and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center and Harvard Medical School.
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65
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Hatazawa Y, Tadaishi M, Nagaike Y, Morita A, Ogawa Y, Ezaki O, Takai-Igarashi T, Kitaura Y, Shimomura Y, Kamei Y, Miura S. PGC-1α-mediated branched-chain amino acid metabolism in the skeletal muscle. PLoS One 2014; 9:e91006. [PMID: 24638054 PMCID: PMC3956461 DOI: 10.1371/journal.pone.0091006] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 02/06/2014] [Indexed: 11/20/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α) is a coactivator of various nuclear receptors and other transcription factors, which is involved in the regulation of energy metabolism, thermogenesis, and other biological processes that control phenotypic characteristics of various organ systems including skeletal muscle. PGC-1α in skeletal muscle is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Branched-chain amino acid (BCAA) metabolism mainly occurs in skeletal muscle mitochondria, and enzymes related to BCAA metabolism are increased by exercise. Using murine skeletal muscle overexpressing PGC-1α and cultured cells, we investigated whether PGC-1α stimulates BCAA metabolism by increasing the expression of enzymes involved in BCAA metabolism. Transgenic mice overexpressing PGC-1α specifically in the skeletal muscle had increased the expression of branched-chain aminotransferase (BCAT) 2, branched-chain α-keto acid dehydrogenase (BCKDH), which catabolize BCAA. The expression of BCKDH kinase (BCKDK), which phosphorylates BCKDH and suppresses its enzymatic activity, was unchanged. The amount of BCAA in the skeletal muscle was significantly decreased in the transgenic mice compared with that in the wild-type mice. The amount of glutamic acid, a metabolite of BCAA catabolism, was increased in the transgenic mice, suggesting the activation of muscle BCAA metabolism by PGC-1α. In C2C12 cells, the overexpression of PGC-1α significantly increased the expression of BCAT2 and BCKDH but not BCKDK. Thus, PGC-1α in the skeletal muscle is considered to significantly contribute to BCAA metabolism.
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Affiliation(s)
- Yukino Hatazawa
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Miki Tadaishi
- Department of Food Function and Labeling, National Institute of Health and Nutrition, Tokyo, Japan
| | - Yuta Nagaike
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Akihito Morita
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yoshihiro Ogawa
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Osamu Ezaki
- Department of Human Health and Design, Showa Women's University, Tokyo, Japan
| | - Takako Takai-Igarashi
- Department of Health Record Informatics, Tohoku Medical Megabank Organization, Tohoku University, Miyagi, Japan
| | - Yasuyuki Kitaura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yoshiharu Shimomura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yasutomi Kamei
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
- * E-mail: (YS); (SM)
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
- * E-mail: (YS); (SM)
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66
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Svensson K, Handschin C. Modulation of PGC-1α activity as a treatment for metabolic and muscle-related diseases. Drug Discov Today 2014; 19:1024-9. [PMID: 24631683 DOI: 10.1016/j.drudis.2014.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 02/27/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Kristoffer Svensson
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Christoph Handschin
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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67
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Yang CS, Kim JJ, Lee HM, Jin HS, Lee SH, Park JH, Kim SJ, Kim JM, Han YM, Lee MS, Kweon GR, Shong M, Jo EK. The AMPK-PPARGC1A pathway is required for antimicrobial host defense through activation of autophagy. Autophagy 2014; 10:785-802. [PMID: 24598403 DOI: 10.4161/auto.28072] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a crucial energy sensor and plays a key role in integration of cellular functions to maintain homeostasis. Despite this, it is largely unknown whether targeting the AMPK pathway can be used as a therapeutic strategy for infectious diseases. Herein, we show that AMPK activation robustly induces antibacterial autophagy, which contributes to antimicrobial defense against Mycobacterium tuberculosis (Mtb). AMPK activation led to inhibition of Mtb-induced phosphorylation of the mechanistic target of rapamycin (MTOR) in macrophages. In addition, AMPK activation increased the genes involved in oxidative phosphorylation, mitochondrial ATP production, and biogenesis in Mtb-infected macrophages. Notably, peroxisome proliferator-activated receptor-gamma, coactivator 1α (PPARGC1A) was required for AMPK-mediated antimicrobial activity, as well as enhancement of mitochondrial function and biogenesis, in macrophages. Further, the AMPK-PPARGC1A pathway was involved in the upregulation of multiple autophagy-related genes via CCAAT/enhancer binding protein (C/EBP), β (CEBPB). PPARGC1A knockdown inhibited the AMPK-mediated induction of autophagy and impaired the fusion of phagosomes with MAP1LC3B (LC3B) autophagosomes in Mtb-infected macrophages. The link between autophagy, mitochondrial function, and antimicrobial activity was further demonstrated by studying LysMCre-mediated knockout of atg7, demonstrating mitochondrial ultrastructural defects and dysfunction, as well as blockade of antimicrobial activity against mycobacteria. Collectively, our results identify the AMPK-PPARGC1A axis as contributing to autophagy activation leading to an antimicrobial response, as a novel host defense mechanism.
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Affiliation(s)
- Chul-Su Yang
- Department of Microbiology; Chungnam National University School of Medicine; Daejeon, Korea; Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea
| | - Jwa-Jin Kim
- Department of Microbiology; Chungnam National University School of Medicine; Daejeon, Korea; Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea
| | - Hye-Mi Lee
- Department of Microbiology; Chungnam National University School of Medicine; Daejeon, Korea; Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea
| | - Hyo Sun Jin
- Department of Microbiology; Chungnam National University School of Medicine; Daejeon, Korea; Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea
| | - Sang-Hee Lee
- BioMedical Research Center; Korea Advanced Institute of Science and Technology; Daejeon, Korea
| | - Ji-Hoon Park
- Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea; Department of Biochemistry; Chungnam National University School of Medicine; Daejeon, Korea
| | - Soung Jung Kim
- Department of Internal Medicine and Research Center for Endocrine and Metabolic Diseases; Chungnam National University School of Medicine; Daejeon, Korea
| | - Jin-Man Kim
- Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea; Department of Pathology; Chungnam National University School of Medicine; Daejeon, Korea
| | - Yong-Mahn Han
- Department of Biological Sciences and Center for Stem Cell Differentiation; Korea Advanced Institute of Science and Technology; Daejeon, Korea
| | - Myung-Shik Lee
- Department of Medicine; Samsung Medical Center; Sungkyunkwan University School of Medicine; Seoul, Korea
| | - Gi Ryang Kweon
- Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea; Department of Biochemistry; Chungnam National University School of Medicine; Daejeon, Korea
| | - Minho Shong
- Department of Internal Medicine and Research Center for Endocrine and Metabolic Diseases; Chungnam National University School of Medicine; Daejeon, Korea
| | - Eun-Kyeong Jo
- Department of Microbiology; Chungnam National University School of Medicine; Daejeon, Korea; Infection Signaling Network Research Center; Chungnam National University School of Medicine; Daejeon, Korea
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68
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Miura S, Tadaishi M, Kamei Y, Ezaki O. Mechanisms of exercise- and training-induced fatty acid oxidation in skeletal muscle. THE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2014. [DOI: 10.7600/jpfsm.3.43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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69
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Dietary stimulators of the PGC-1 superfamily and mitochondrial biosynthesis in skeletal muscle. A mini-review. J Physiol Biochem 2013; 70:271-84. [DOI: 10.1007/s13105-013-0301-4] [Citation(s) in RCA: 260] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/21/2013] [Indexed: 11/26/2022]
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70
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Jamart C, Naslain D, Gilson H, Francaux M. Higher activation of autophagy in skeletal muscle of mice during endurance exercise in the fasted state. Am J Physiol Endocrinol Metab 2013; 305:E964-74. [PMID: 23964069 DOI: 10.1152/ajpendo.00270.2013] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of autophagy in skeletal muscle has been reported in response to endurance exercise and food deprivation independently. The purpose of this study was to evaluate whether autophagy was more activated when both stimuli were combined, namely when endurance exercise was performed in a fasted rather than a fed state. Mice performed a low-intensity running exercise (10 m/min for 90min) in both dietary states after which the gastrocnemius muscles were removed. LC3b-II, a marker of autophagosome presence, increased in both conditions, but the increase was higher in the fasted state. Other protein markers of autophagy, like Gabarapl1-II and Atg12 conjugated form as well as mRNA of Lc3b, Gabarapl1, and p62/Sqstm1 were increased only when exercise was performed in a fasted state. The larger activation of autophagy by exercise in a fasted state was associated with a larger decrease in plasma insulin and phosphorylation of Akt(Ser473), Akt(Thr308), FoxO3a(Thr32), and ULK1(Ser757). AMPKα(Thr172), ULK1(Ser317), and ULK1(Ser555) remained unchanged in both conditions, whereas p38(Thr180/Tyr182) increased during exercise to a similar extent in the fasted and fed conditions. The marker of mitochondrial fission DRP1(Ser616) was increased by exercise independently of the nutritional status. Changes in mitophagy markers BNIP3 and Parkin suggest that mitophagy was increased during exercise in the fasted state. In conclusion, our results highlight a major implication of the insulin-Akt-mTOR pathway and its downstream targets FoxO3a and ULK1 in the larger activation of autophagy observed when exercise is performed in a fasted state compared with a fed state.
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Affiliation(s)
- Cécile Jamart
- Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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71
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Whitaker RM, Wills LP, Stallons LJ, Schnellmann RG. cGMP-selective phosphodiesterase inhibitors stimulate mitochondrial biogenesis and promote recovery from acute kidney injury. J Pharmacol Exp Ther 2013; 347:626-34. [PMID: 24042162 DOI: 10.1124/jpet.113.208017] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Recent studies demonstrate that mitochondrial dysfunction is a mediator of acute kidney injury (AKI). Consequently, restoration of mitochondrial function after AKI may be key to the recovery of renal function. Mitochondrial function can be restored through the generation of new, functional mitochondria in a process called mitochondrial biogenesis (MB). Despite its potential therapeutic significance, very few pharmacological agents have been identified to induce MB. To examine the efficacy of phosphodiesterase (PDE) inhibitors (PDE3: cAMP and cGMP activity; and PDE4: cAMP activity) in stimulating MB, primary cultures of renal proximal tubular cells (RPTCs) were treated with a panel of inhibitors for 24 hours. PDE3, but not PDE4, inhibitors increased the FCCP-uncoupled oxygen consumption rate (OCR), a marker of MB. Exposure of RPTCs to the PDE3 inhibitors, cilostamide and trequinsin, for 24 hours increased peroxisome proliferator-activated receptor γ coactivator-1α, and multiple mitochondrial electron transport chain genes. Cilostamide and trequinsin also increased mRNA expression of mitochondrial genes and mitochondrial DNA copy number in mice renal cortex. Consistent with these experiments, 8-Br-cGMP increased FCCP-uncoupled OCR and mitochondrial gene expression, whereas 8-Br-cAMP had no effect. The cGMP-specific PDE5 inhibitor sildenafil also induced MB in RPTCs and in vivo in mouse renal cortex. Treatment of mice with sildenafil after folic acid-induced AKI promoted restoration of MB and renal recovery. These data provide strong evidence that specific PDE inhibitors that increase cGMP are inducers of MB in vitro and in vivo, and suggest their potential efficacy in AKI and other diseases characterized by mitochondrial dysfunction and suppressed MB.
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Affiliation(s)
- Ryan M Whitaker
- Center for Cell Death, Injury, and Regeneration, Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina; and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
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72
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Miura S, Kai Y, Tadaishi M, Tokutake Y, Sakamoto K, Bruce CR, Febbraio MA, Kita K, Chohnan S, Ezaki O. Marked phenotypic differences of endurance performance and exercise-induced oxygen consumption between AMPK and LKB1 deficiency in mouse skeletal muscle: changes occurring in the diaphragm. Am J Physiol Endocrinol Metab 2013; 305:E213-29. [PMID: 23695215 DOI: 10.1152/ajpendo.00114.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
LKB1 phosphorylates members of the AMP-activated protein kinase (AMPK) family. LKB1 and AMPK in the skeletal muscle are believed to regulate not only fuel oxidation during exercise but also exercise capacity. LKB1 was also required to prevent diaphragm fatigue, which was shown to affect exercise performance. Using mice expressing dominant negative (DN) mutants of LKB1 and AMPK, specifically in the skeletal muscle but not in the heart, we investigated the roles of LKB1 and AMPK activity in exercise performance and the effects of these kinases on the characteristics of respiratory and locomotive muscles. In the diaphragm and gastrocnemius, both AMPK-DN and LKB1-DN mice showed complete loss of AMPKα2 activity, and LKB1-DN mice showed a reduction in LKB1 activity. Exercise capacity was significantly reduced in LKB1-DN mice, with a marked reduction in oxygen consumption and carbon dioxide production during exercise. The diaphragm from LKB1-DN mice showed an increase in myosin heavy chain IIB and glycolytic enzyme expression. Normal respiratory chain function and CPT I activity were shown in the isolated mitochondria from LKB1-DN locomotive muscle, and the expression of genes related to fiber type, mitochondria function, glucose and lipid metabolism, and capillarization in locomotive muscle was not different between LKB1-DN and AMPK-DN mice. We concluded that LKB1 in the skeletal muscle contributes significantly to exercise capacity and oxygen uptake during exercise. LKB1 mediated the change of fiber-type distribution in the diaphragm independently of AMPK and might be responsible for the phenotypes we observed.
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Affiliation(s)
- Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan.
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73
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Wang SCM, Muscat GEO. Nuclear receptors and epigenetic signaling: novel regulators of glycogen metabolism in skeletal muscle. IUBMB Life 2013; 65:657-64. [PMID: 23846999 DOI: 10.1002/iub.1181] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/18/2013] [Indexed: 02/04/2023]
Abstract
Glycogen is an energy storage depot for the mammalian species. This review focuses on recent developments that have identified the role of nuclear hormone receptor (NR) signaling and epigenomic control in the regulation of important genes that modulate glycogen metabolism. Specifically, new studies have revealed that the NR4A subgroup (of the NR superfamily) are strikingly sensitive to beta-adrenergic stimulation in skeletal muscle, and transgenic studies in mice have revealed the expression of these NRs affects endurance and glycogen levels in muscle. Furthermore, other studies have demonstrated that one of the NR coregulator class of enzymes that mediate chromatin remodeling, the histone methyltransferases (for example, protein arginine methyltransferase 4) regulates the expression of several genes involved in glycogen metabolism and glycogen storage diseases in skeletal muscle. Importantly, NRs and histone methyltransferases, have the potential to be pharmacologically exploited and may provide novel targets in the quest to treat disorders of glycogen storage.
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Affiliation(s)
- Shu-Ching Mary Wang
- The University of Queensland, Institute for Molecular Bioscience, Obesity Research Centre, Australia
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74
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Ramjiawan A, Bagchi RA, Blant A, Albak L, Cavasin MA, Horn TR, McKinsey TA, Czubryt MP. Roles of histone deacetylation and AMP kinase in regulation of cardiomyocyte PGC-1α gene expression in hypoxia. Am J Physiol Cell Physiol 2013; 304:C1064-72. [DOI: 10.1152/ajpcell.00262.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transcriptional coactivator peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a key determinant of cardiac metabolic function by regulating genes governing fatty acid oxidation and mitochondrial biogenesis. PGC-1α expression is reduced in many cardiac diseases, and gene deletion of PGC-1α results in impaired cardiomyocyte metabolism and function. Reduced fuel supply generally induces PGC-1α expression, but the specific role of oxygen deprivation is unclear, and the mechanisms governing PGC-1α gene expression in these situations are poorly understood. During hypoxia of primary rat cardiomyocytes up to 12 h, we found that PGC-1α expression was downregulated via a histone deacetylation-dependent mechanism. Conversely, extended hypoxia to 24 h concomitant with glucose depletion upregulated PGC-1α expression via an AMP-activated protein kinase (AMPK)-mediated mechanism. Our previous work demonstrated that estrogen-related receptor-α (ERRα) regulates PGC-1α expression, and we show here that overexpression of ERRα was sufficient to attenuate PGC-1α downregulation in hypoxia. We confirmed that chronic hypoxia downregulated cardiac PGC-1α expression in a hypoxic but nonischemic hypobaric rat model of pulmonary hypertension. Our data demonstrate that depletion of oxygen or fuel results in repression or induction, respectively, of PGC-1α expression via discrete mechanisms, which may contribute to cardiac energetic derangement during hypoxia, ischemia, and failure.
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Affiliation(s)
- Angela Ramjiawan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada; and
| | | | - Alexandra Blant
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada; and
| | - Laura Albak
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada; and
| | - Maria A. Cavasin
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, Colorado
| | - Todd R. Horn
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, Colorado
| | - Timothy A. McKinsey
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, Colorado
| | - Michael P. Czubryt
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada; and
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75
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New insights in the regulation of skeletal muscle PGC-1α by exercise and metabolic diseases. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.ddmod.2012.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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76
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Kim SH, Asaka M, Higashida K, Takahashi Y, Holloszy JO, Han DH. β-Adrenergic stimulation does not activate p38 MAP kinase or induce PGC-1α in skeletal muscle. Am J Physiol Endocrinol Metab 2013; 304:E844-52. [PMID: 23443926 PMCID: PMC3625780 DOI: 10.1152/ajpendo.00581.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/08/2013] [Indexed: 12/16/2022]
Abstract
There are reports that the β-adrenergic agonist clenbuterol induces a large increase in peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in skeletal muscle. This has led to the hypothesis that the increases in PGC-1α and mitochondrial biogenesis induced in muscle by endurance exercise are mediated by catecholamines. In the present study, we evaluated this possibility and found that injecting rats with clenbuterol or norepinephrine induced large increases in PGC-1α and mitochondrial proteins in brown adipose tissue but had no effect on PGC-1α expression or mitochondrial biogenesis in skeletal muscle. In brown adipocytes, the increase in PGC-1α expression induced by β-adrenergic stimulation is mediated by activation of p38 mitogen-activated protein kinase (p38 MAPK), which phosphorylates and activates the cAMP response element binding protein (CREB) family member activating transcription factor 2 (ATF2), which binds to a cyclic AMP response element (CRE) in the PGC-1α promoter and mediates the increase in PGC-1α transcription. Phospho-CREB does not have this effect. Our results show that the reason for the lack of effect of β-adrenergic stimulation on PGC-1α expression in muscle is that catecholamines do not activate p38 or increase ATF2 phosphorylation in muscle.
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MESH Headings
- Activating Transcription Factor 2/metabolism
- Adipose Tissue, Brown/cytology
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/enzymology
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic beta-Agonists/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Aminoimidazole Carboxamide/analogs & derivatives
- Aminoimidazole Carboxamide/pharmacology
- Animals
- Cells, Cultured
- Clenbuterol/pharmacology
- Cyclic AMP Response Element-Binding Protein/metabolism
- Enzyme Activation/drug effects
- Enzyme Activation/physiology
- Gene Expression/drug effects
- Gene Expression/physiology
- Hypoglycemic Agents/pharmacology
- Male
- Mice
- Muscle, Skeletal/cytology
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/physiology
- Myoblasts, Skeletal/cytology
- Myoblasts, Skeletal/drug effects
- Myoblasts, Skeletal/enzymology
- Norepinephrine/pharmacology
- Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
- Phosphorylation/drug effects
- Phosphorylation/physiology
- Physical Endurance/physiology
- Propranolol/pharmacology
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Rats
- Rats, Wistar
- Ribonucleotides/pharmacology
- Transcription Factors/genetics
- Transcription Factors/metabolism
- p38 Mitogen-Activated Protein Kinases/metabolism
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Affiliation(s)
- Sang Hyun Kim
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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77
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O'Neill HM, Holloway GP, Steinberg GR. AMPK regulation of fatty acid metabolism and mitochondrial biogenesis: implications for obesity. Mol Cell Endocrinol 2013; 366:135-51. [PMID: 22750049 DOI: 10.1016/j.mce.2012.06.019] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/13/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
Skeletal muscle plays an important role in regulating whole-body energy expenditure given it is a major site for glucose and lipid oxidation. Obesity and type 2 diabetes are causally linked through their association with skeletal muscle insulin resistance, while conversely exercise is known to improve whole body glucose homeostasis simultaneously with muscle insulin sensitivity. Exercise activates skeletal muscle AMP-activated protein kinase (AMPK). AMPK plays a role in regulating exercise capacity, skeletal muscle mitochondrial content and contraction-stimulated glucose uptake. Skeletal muscle AMPK is also thought to be important for regulating fatty acid metabolism; however, direct genetic evidence in this area is currently lacking. This review will discuss the current paradigms regarding the influence of AMPK in regulating skeletal muscle fatty acid metabolism and mitochondrial biogenesis at rest and during exercise, and highlight the potential implications in the development of insulin resistance.
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Affiliation(s)
- Hayley M O'Neill
- University of Melbourne, Department of Medicine, St. Vincent's Institute of Medical Research, Melbourne, Victoria, Australia.
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78
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Abstract
Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12 to 15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50% to 1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking approximately five times per week, at a significant intensity that requires frequent rest periods, are most significant. Preclinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, and mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a lifestyle pattern that includes enhanced physical activity prior to the advance of PAD limitations is the most desirable and beneficial.
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Affiliation(s)
- Tara L Haas
- Angiogenesis Research Group, Muscle Health Research Centre, Faculty of Health, York University, Toronto, Ontario, Canada
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79
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Abstract
Sarcopenia remains largely undiagnosed and undertreated because of the lack of a universally accepted definition, effective ways to measure it, and identification of the outcomes that should guide treatment efficacy. An ever-growing number of clinicians and researchers along with funding and regulatory agencies have gradually recognized that sarcopenia is a human condition that requires both prevention and treatment. In this article, we review sarcopenia and its common and less known pharmacological treatments, attempt to define sarcopenia in its broader context, and present some new ideas for potential future treatment for this devastating condition.
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Affiliation(s)
- Marco Brotto
- Muscle Biology Research Group-MUBIG, University of Missouri-Kansas City, School of Nursing, Kansas City, MO 64108, USA.
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80
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Santulli G, Lombardi A, Sorriento D, Anastasio A, Del Giudice C, Formisano P, Béguinot F, Trimarco B, Miele C, Iaccarino G. Age-related impairment in insulin release: the essential role of β(2)-adrenergic receptor. Diabetes 2012; 61:692-701. [PMID: 22315324 PMCID: PMC3282797 DOI: 10.2337/db11-1027] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In this study, we investigated the significance of β(2)-adrenergic receptor (β(2)AR) in age-related impaired insulin secretion and glucose homeostasis. We characterized the metabolic phenotype of β(2)AR-null C57Bl/6N mice (β(2)AR(-/-)) by performing in vivo and ex vivo experiments. In vitro assays in cultured INS-1E β-cells were carried out in order to clarify the mechanism by which β(2)AR deficiency affects glucose metabolism. Adult β(2)AR(-/-) mice featured glucose intolerance, and pancreatic islets isolated from these animals displayed impaired glucose-induced insulin release, accompanied by reduced expression of peroxisome proliferator-activated receptor (PPAR)γ, pancreatic duodenal homeobox-1 (PDX-1), and GLUT2. Adenovirus-mediated gene transfer of human β(2)AR rescued these defects. Consistent effects were evoked in vitro both upon β(2)AR knockdown and pharmacologic treatment. Interestingly, with aging, wild-type (β(2)AR(+/+)) littermates developed impaired insulin secretion and glucose tolerance. Moreover, islets from 20-month-old β(2)AR(+/+) mice exhibited reduced density of β(2)AR compared with those from younger animals, paralleled by decreased levels of PPARγ, PDX-1, and GLUT2. Overexpression of β(2)AR in aged mice rescued glucose intolerance and insulin release both in vivo and ex vivo, restoring PPARγ/PDX-1/GLUT2 levels. Our data indicate that reduced β(2)AR expression contributes to the age-related decline of glucose tolerance in mice.
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Affiliation(s)
- Gaetano Santulli
- Department of Clinical Medicine, Cardiovascular & Immunologic Sciences, “Federico II” University of Naples, Naples, Italy
- Columbia-Presbyterian Medical Center, College of Physicians & Surgeons, Columbia University, New York, New York
| | - Angela Lombardi
- Columbia University Medical Center, Columbia University, New York, New York
- Department of Cellular and Molecular Biology and Pathology and Institute of Experimental Endocrinology and Oncology “Gaetano Salvatore,” “Federico II” University of Naples, Naples, Italy
| | - Daniela Sorriento
- Department of Clinical Medicine, Cardiovascular & Immunologic Sciences, “Federico II” University of Naples, Naples, Italy
| | - Antonio Anastasio
- Department of Clinical Medicine, Cardiovascular & Immunologic Sciences, “Federico II” University of Naples, Naples, Italy
| | - Carmine Del Giudice
- Department of Clinical Medicine, Cardiovascular & Immunologic Sciences, “Federico II” University of Naples, Naples, Italy
| | - Pietro Formisano
- Department of Cellular and Molecular Biology and Pathology and Institute of Experimental Endocrinology and Oncology “Gaetano Salvatore,” “Federico II” University of Naples, Naples, Italy
| | - Francesco Béguinot
- Department of Cellular and Molecular Biology and Pathology and Institute of Experimental Endocrinology and Oncology “Gaetano Salvatore,” “Federico II” University of Naples, Naples, Italy
| | - Bruno Trimarco
- Department of Clinical Medicine, Cardiovascular & Immunologic Sciences, “Federico II” University of Naples, Naples, Italy
| | - Claudia Miele
- Department of Cellular and Molecular Biology and Pathology and Institute of Experimental Endocrinology and Oncology “Gaetano Salvatore,” “Federico II” University of Naples, Naples, Italy
- Corresponding authors: Guido Iaccarino, , and Claudia Miele,
| | - Guido Iaccarino
- School of Medicine, University of Salerno, Salerno, Italy
- Corresponding authors: Guido Iaccarino, , and Claudia Miele,
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Abstract
The increasing prevalence of obesity and its comorbidities represents a major threat to human health globally. Pharmacological treatments exist to achieve weight loss, but the subsequent weight maintenance is prone to fail in the long run. Accordingly, efficient new strategies to persistently control body weight need to be elaborated. Exercise and dietary interventions constitute classical approaches to reduce and maintain body weight, yet people suffering from metabolic diseases are often unwilling or unable to move adequately. The administration of drugs that partially mimic exercise adaptation might circumvent this problem by easing and supporting physical activity. The thermogenic peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) largely mediates the adaptive response of skeletal muscle to endurance exercise and is a potential target for such interventions. Here, we review the role of PGC-1α in mediating exercise adaptation, coordinating metabolic circuits and enhancing thermogenic capacity in skeletal muscle. We suggest a combination of elevated muscle PGC-1α and exercise as a modified approach for the efficient long-term control of body weight and the treatment of the metabolic syndrome.
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Affiliation(s)
- S Summermatter
- Biozentrum, Division of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
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82
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Chang JS, Fernand V, Zhang Y, Shin J, Jun HJ, Joshi Y, Gettys TW. NT-PGC-1α protein is sufficient to link β3-adrenergic receptor activation to transcriptional and physiological components of adaptive thermogenesis. J Biol Chem 2012; 287:9100-11. [PMID: 22282499 DOI: 10.1074/jbc.m111.320200] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PGC-1α is an inducible transcriptional coactivator that regulates cellular energy metabolism and adaptation to environmental and nutritional stimuli. In tissues expressing PGC-1α, alternative splicing produces a truncated protein (NT-PGC-1α) corresponding to the first 267 amino acids of PGC-1α. Brown adipose tissue also expresses two novel exon 1b-derived isoforms of PGC-1α and NT-PGC-1α, which are 4 and 13 amino acids shorter in the N termini than canonical PGC-1α and NT-PGC-1α, respectively. To evaluate the ability of NT-PGC-1α to substitute for PGC-1α and assess the isoform-specific role of NT-PGC-1α, adaptive thermogenic responses of adipose tissue were evaluated in mice lacking full-length PGC-1α (FL-PGC-1(-/-)) but expressing slightly shorter but functionally equivalent forms of NT-PGC-1α (NT-PGC-1α(254)). At room temperature, NT-PGC-1α and NT-PGC-1α(254) were produced from conventional exon 1a-derived transcripts in brown adipose tissue of wild type and FL-PGC-1α(-/-) mice, respectively. However, cold exposure shifted transcription to exon 1b, increasing exon 1b-derived mRNA levels. The resulting transcriptional responses produced comparable increases in energy expenditure and maintenance of core body temperature in WT and FL-PGC-1α(-/-) mice. Moreover, treatment of the two genotypes with a selective β(3)-adrenergic receptor agonist produced similar increases in energy expenditure, mitochondrial DNA, and reductions in adiposity. Collectively, these findings illustrate that the transcriptional and physiological responses to sympathetic input are unabridged in FL-PGC-1α(-/-) mice, and that NT-PGC-1α is sufficient to link β(3)-androgenic receptor activation to adaptive thermogenesis in adipose tissue. Furthermore, the transcriptional shift from exon 1a to 1b supports isoform-specific roles for NT-PGC-1α in basal and adaptive thermogenesis.
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Affiliation(s)
- Ji Suk Chang
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA
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83
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AICAR prevents heat-induced sudden death in RyR1 mutant mice independent of AMPK activation. Nat Med 2012; 18:244-51. [PMID: 22231556 PMCID: PMC3274651 DOI: 10.1038/nm.2598] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/08/2011] [Indexed: 11/08/2022]
Abstract
Mice with a knock-in mutation (Y524S) in the type I ryanodine receptor (RyR1) die when exposed to short periods of temperature elevation (≥ 37 °C). We demonstrate that treatment with 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) prevents heat-induced sudden death in Y524S mice. The AICAR protection is independent of AMPK activation and results from a newly identified action on the mutant RyR1 to reduce Ca2+ leak, preventing Ca2+ dependent increases in both reactive oxygen and reactive nitrogen species that act to further increase resting Ca2+ concentrations. If unchecked, the temperature driven increases in resting Ca2+ and ROS/RNS create an amplifying cycle that ultimately triggers sustained muscle contractions, rhabdomyolysis and death. Although antioxidants are effective in reducing this cycle in vitro, only AICAR prevents the heat induced death in vivo. Our findings suggest that AICAR is likely to be effective in prophylactic treatment of humans with enhanced susceptibility to exercise/heat-induced sudden death associated with RyR1 mutations.
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84
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Skeletal muscle-specific expression of PGC-1α-b, an exercise-responsive isoform, increases exercise capacity and peak oxygen uptake. PLoS One 2011; 6:e28290. [PMID: 22174785 PMCID: PMC3234261 DOI: 10.1371/journal.pone.0028290] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 11/04/2011] [Indexed: 11/19/2022] Open
Abstract
Background Maximal oxygen uptake (VO2max) predicts mortality and is associated with endurance performance. Trained subjects have a high VO2max due to a high cardiac output and high metabolic capacity of skeletal muscles. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a nuclear receptor coactivator, promotes mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. Because exercise training increases PGC-1α in skeletal muscle, PGC-1α-mediated changes may contribute to the improvement of exercise capacity and VO2max. There are three isoforms of PGC-1α mRNA. PGC-1α-b protein, whose amino terminus is different from PGC-1α-a protein, is a predominant PGC-1α isoform in response to exercise. We investigated whether alterations of skeletal muscle metabolism by overexpression of PGC-1α-b in skeletal muscle, but not heart, would increase VO2max and exercise capacity. Methodology/Principal Findings Transgenic mice showed overexpression of PGC-1α-b protein in skeletal muscle but not in heart. Overexpression of PGC-1α-b promoted mitochondrial biogenesis 4-fold, increased the expression of fatty acid transporters, enhanced angiogenesis in skeletal muscle 1.4 to 2.7-fold, and promoted exercise capacity (expressed by maximum speed) by 35% and peak oxygen uptake by 20%. Across a broad range of either the absolute exercise intensity, or the same relative exercise intensities, lipid oxidation was always higher in the transgenic mice than wild-type littermates, suggesting that lipid is the predominant fuel source for exercise in the transgenic mice. However, muscle glycogen usage during exercise was absent in the transgenic mice. Conclusions/Significance Increased mitochondrial biogenesis, capillaries, and fatty acid transporters in skeletal muscles may contribute to improved exercise capacity via an increase in fatty acid utilization. Increases in PGC-1α-b protein or function might be a useful strategy for sedentary subjects to perform exercise efficiently, which would lead to prevention of life-style related diseases and increased lifespan.
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85
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Norrbom J, Sällstedt EK, Fischer H, Sundberg CJ, Rundqvist H, Gustafsson T. Alternative splice variant PGC-1α-b is strongly induced by exercise in human skeletal muscle. Am J Physiol Endocrinol Metab 2011; 301:E1092-8. [PMID: 21862727 DOI: 10.1152/ajpendo.00119.2011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study investigated whether exercise induces the expression of PGC-1α splice variants in human skeletal muscle and the possible influence of metabolic perturbation on this response. The subjects exercised one leg for 45 min with restricted blood flow (R-leg), followed by 45 min of exercise using the other leg at the same absolute workload but with normal blood flow (NR-leg). This ischemic model (R-leg) has been shown previously to induce a greater metabolic perturbation and enhance the expression of PGC-1α beyond that observed in the NR-leg. Cultured human myotubes were used to test suggested exercise-induced regulatory stimuli of PGC-1α. We showed, for the first time, that transcripts from both the canonical promoter (PGC-1α-a) and the proposed upstream-located promoter (PGC-1α-b) are present in human skeletal muscle. Both transcripts were upregulated after exercise in the R-leg, but the fold change increase of PGC-1α-b was much greater than that of PGC-1α-a. No differences were observed between the two conditions regarding the marker for calcineurin activation, MCIP1, or p38 phosphorylation. AMPK phosphorylation increased to a greater extent in the R-leg, and AICAR stimulation of cultured human myotubes induced the expression of PGC-1α-a and PGC-1α-b. AICAR combined with norepinephrine yielded an additive effect on the PGC-1α-b expression only. Our results indicate clearly that exercise can activate an upstream promoter in humans and support AMPK as a major regulator of transcripts from the canonical PGC-1α promoter and the involvement of β-adrenergic stimulation in combination with AMPK in the regulation of PGC-1α-b.
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Affiliation(s)
- J Norrbom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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86
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Robinson MM, Bell C, Peelor FF, Miller BF. β-Adrenergic receptor blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in humans. Am J Physiol Regul Integr Comp Physiol 2011; 301:R327-34. [PMID: 21613574 DOI: 10.1152/ajpregu.00160.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
β-Adrenergic receptor (AR) signaling is a regulator of skeletal muscle protein synthesis and mitochondrial biogenesis in mice. We hypothesized that β-AR blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in adult humans. Six healthy men (mean ± SD: 26 ± 6 yr old, 39.9 ± 4.9 ml·kg(-1)·min(-1) peak O(2) uptake, 26.7 ± 2.0 kg/m(2) body mass index) performed 1 h of stationary cycle ergometer exercise (60% peak O(2) uptake) during 1) β-AR blockade (intravenous propranolol) and 2) administration of saline (control). Skeletal muscle mitochondrial, myofibrillar, and sarcoplasmic protein synthesis rates were assessed using [(2)H(5)]phenylalanine incorporation into skeletal muscle proteins after exercise. The mRNA content of signals for mitochondrial biogenesis was determined using real-time PCR. β-AR blockade decreased mitochondrial (from 0.217 ± 0.076 to 0.135 ± 0.031%/h, P < 0.05), but not myofibrillar or sarcoplasmic, protein synthesis rates. Peroxisome proliferator-activated receptor-γ coactivator-1α mRNA was increased ∼2.5-fold (P < 0.05) at 5 h compared with 1 h postexercise but was not influenced by β-AR blockade. We conclude that decreased β-AR signaling during cycling can blunt the postexercise increase in mitochondrial protein synthesis rates without affecting mRNA content.
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Affiliation(s)
- Matthew M Robinson
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado 80523, USA
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87
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Mendelsohn A, Larrick JW. Master switch of mitochondrial biogenesis: a clinical target for health span enhancement? Rejuvenation Res 2011; 14:223-6. [PMID: 21595503 DOI: 10.1089/rej.2011.1194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Andrew Mendelsohn
- Panorama Research Institute and Regenerative Sciences Institute, Sunnyvale, California 94089, USA.
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