Dysregulation of Mitochondrial Quality Control Processes Contribute to Sarcopenia in a Mouse Model of Premature Aging

Mitochondrial DNA (mtDNA) mutations lead to decrements in mitochondrial function and accelerated rates of these mutations has been linked to skeletal muscle loss (sarcopenia). The purpose of this study was to investigate the effect of mtDNA mutations on mitochondrial quality control processes in skeletal muscle from animals (young; 3–6 months and older; 8–15 months) expressing a proofreading-deficient version of mtDNA polymerase gamma (PolG). This progeroid aging model exhibits elevated mtDNA mutation rates, mitochondrial dysfunction, and a premature aging phenotype that includes sarcopenia. We found increased expression of the mitochondrial biogenesis regulator peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and its target proteins, nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (Tfam) in PolG animals compared to wild-type (WT) (P<0.05). Muscle from older PolG animals displayed higher mitochondrial fission protein 1 (Fis1) concurrent with greater induction of autophagy, as indicated by changes in Atg5 and p62 protein content (P<0.05). Additionally, levels of the Tom22 import protein were higher in PolG animals when compared to WT (P<0.05). In contrast, muscle from normally-aged animals exhibited a distinctly different expression profile compared to PolG animals. Older WT animals appeared to have higher fusion (greater Mfn1/Mfn2, and lower Fis1) and lower autophagy (Beclin-1 and p62) compared to young WT suggesting that autophagy is impaired in aging muscle. In conclusion, muscle from mtDNA mutator mice display higher mitochondrial fission and autophagy levels that likely contribute to the sarcopenic phenotype observed in premature aging and this differs from the response observed in normally-aged muscle.

[1]  Jan Nedergaard,et al.  Random point mutations with major effects on protein-coding genes are the driving force behind premature aging in mtDNA mutator mice. , 2009, Cell metabolism.

[2]  U. Brunk,et al.  The lysosomal-mitochondrial axis theory of postmitotic aging and cell death. , 2006, Chemico-biological interactions.

[3]  J. Aiken,et al.  Age-associated Changes in Function, Structure and Mitochondrial Genetic and Enzymatic Abnormalities in the Fischer 344×Brown Norway F1Hybrid Rat Heart , 2002 .

[4]  Mitochondrial pathways in sarcopenia of aging and disuse muscle atrophy , 2013, Biological chemistry.

[5]  J. Shaw,et al.  Dnm1p Gtpase-Mediated Mitochondrial Fission Is a Multi-Step Process Requiring the Novel Integral Membrane Component Fis1p , 2000, The Journal of cell biology.

[6]  T. Manini,et al.  The impact of aging on mitochondrial function and biogenesis pathways in skeletal muscle of sedentary high‐ and low‐functioning elderly individuals , 2012, Aging cell.

[7]  K. Truscott,et al.  Insertion and Assembly of Human Tom7 into the Preprotein Translocase Complex of the Outer Mitochondrial Membrane* , 2002, The Journal of Biological Chemistry.

[8]  C. Hoppel,et al.  Studies on Giant Mitochondria , 1986, Annals of the New York Academy of Sciences.

[9]  Young-sil Yoon,et al.  Formation of elongated giant mitochondria in DFO‐induced cellular senescence: Involvement of enhanced fusion process through modulation of Fis1 , 2006, Journal of cellular physiology.

[10]  A. Hegde,et al.  NRF-1 is the major transcription factor regulating the expression of the human TOMM34 gene. , 2008, Biochemistry and cell biology = Biochimie et biologie cellulaire.

[11]  S. Salamat,et al.  Mitochondrial DNA-deletion mutations accumulate intracellularly to detrimental levels in aged human skeletal muscle fibers. , 2006, American journal of human genetics.

[12]  A. Betik,et al.  No decline in skeletal muscle oxidative capacity with aging in long-term calorically restricted rats: effects are independent of mitochondrial DNA integrity. , 2006, The journals of gerontology. Series A, Biological sciences and medical sciences.

[13]  C. Leeuwenburgh,et al.  Skeletal muscle autophagy and apoptosis during aging: Effects of calorie restriction and life-long exercise , 2010, Experimental Gerontology.

[14]  C. Leeuwenburgh,et al.  Age- and calorie restriction-related changes in rat brain mitochondrial DNA and TFAM binding , 2012, AGE.

[15]  D. Hood,et al.  Thyroid hormone modifies mitochondrial phenotype by increasing protein import without altering degradation. , 1998, American journal of physiology. Cell physiology.

[16]  D. Harman Free radical theory of aging: dietary implications , 1972 .

[17]  B. Robinson,et al.  Events upstream of mitochondrial protein import limit the oxidative capacity of fibroblasts in multiple mitochondrial disease. , 2002, Biochimica et biophysica acta.

[18]  Michael F. N. O'Leary,et al.  Effect of denervation on mitochondrially mediated apoptosis in skeletal muscle. , 2007, Journal of applied physiology.

[19]  D. Hood Plasticity in Skeletal, Cardiac, and Smooth Muscle Invited Review: Contractile activity-induced mitochondrial biogenesis in skeletal muscle , 2001 .

[20]  Tilman Grune,et al.  Lipofuscin: formation, distribution, and metabolic consequences. , 2007, Annals of the New York Academy of Sciences.

[21]  O. Shirihai,et al.  Mitochondrial fusion, fission and autophagy as a quality control axis: the bioenergetic view. , 2008, Biochimica et biophysica acta.

[22]  M. Tarnopolsky,et al.  Mitochondrial myopathies: diagnosis, exercise intolerance, and treatment options. , 2005, Medicine and science in sports and exercise.

[23]  T. Prolla,et al.  Mitochondrial Fusion Is Required for mtDNA Stability in Skeletal Muscle and Tolerance of mtDNA Mutations , 2010, Cell.

[24]  J. Blesa,et al.  NRF-2 transcription factor is required for human TOMM20 gene expression. , 2007, Gene.

[25]  T. Prolla,et al.  Increased mitochondrial biogenesis in muscle improves aging phenotypes in the mtDNA mutator mouse. , 2012, Human molecular genetics.

[26]  H. Pilegaard,et al.  The role of PGC-1alpha on mitochondrial function and apoptotic susceptibility in muscle. , 2009, American journal of physiology. Cell physiology.

[27]  D. Wallace,et al.  Mouse models for mitochondrial disease. , 2001, American journal of medical genetics.

[28]  E. Dupont-Versteegden,et al.  Age-related changes of cell death pathways in rat extraocular muscle , 2009, Experimental Gerontology.

[29]  H. Westerblad,et al.  Impaired mitochondrial respiration and decreased fatigue resistance followed by severe muscle weakness in skeletal muscle of mitochondrial DNA mutator mice , 2012, The Journal of physiology.

[30]  D. Stojanovski,et al.  Dissection of the Mitochondrial Import and Assembly Pathway for Human Tom40* , 2005, Journal of Biological Chemistry.

[31]  Jiandie D. Lin,et al.  Transcriptional co-activator PGC-1 alpha drives the formation of slow-twitch muscle fibres. , 2002, Nature.

[32]  Terje Johansen,et al.  p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on huntingtin-induced cell death , 2005, The Journal of cell biology.

[33]  M. Sandri,et al.  Mitochondrial Biogenesis and Fragmentation as Regulators of Muscle Protein Degradation , 2010, Current hypertension reports.

[34]  K. Mihara,et al.  Two mitofusin proteins, mammalian homologues of FZO, with distinct functions are both required for mitochondrial fusion. , 2003, Journal of biochemistry.

[35]  Howard T. Jacobs,et al.  Premature ageing in mice expressing defective mitochondrial DNA polymerase , 2004, Nature.

[36]  K. Nair,et al.  Skeletal muscle aging and the mitochondrion , 2013, Trends in Endocrinology & Metabolism.

[37]  B. Robinson,et al.  Compensatory responses of protein import and transcription factor expression in mitochondrial DNA defects. , 2004, American journal of physiology. Cell physiology.

[38]  J. Aiken,et al.  Mitochondrial DNA deletion mutations colocalize with segmental electron transport system abnormalities, muscle fiber atrophy, fiber splitting, and oxidative damage in sarcopenia , 2001, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[39]  G. Bjørkøy,et al.  p62/SQSTM1 Binds Directly to Atg8/LC3 to Facilitate Degradation of Ubiquitinated Protein Aggregates by Autophagy* , 2007, Journal of Biological Chemistry.

[40]  N. Larsson Somatic mitochondrial DNA mutations in mammalian aging. , 2010, Annual review of biochemistry.

[41]  Ana Maria Cuervo,et al.  Autophagy and Aging: The Importance of Maintaining "Clean" Cells , 2005, Autophagy.

[42]  Y. Kubo,et al.  Primary Structure of a Dynamin-related Mouse Mitochondrial GTPase and Its Distribution in Brain, Subcellular Localization, and Effect on Mitochondrial Morphology* , 2002, The Journal of Biological Chemistry.

[43]  Gregory C Kujoth,et al.  Endurance exercise rescues progeroid aging and induces systemic mitochondrial rejuvenation in mtDNA mutator mice , 2011, Proceedings of the National Academy of Sciences.

[44]  J. Hayashi,et al.  Inter-mitochondrial complementation: Mitochondria-specific system preventing mice from expression of disease phenotypes by mutant mtDNA , 2001, Nature Medicine.

[45]  Hong-Gang Wang,et al.  The Association of AMPK with ULK1 Regulates Autophagy , 2010, PloS one.

[46]  Luca Scorrano,et al.  Mitochondrial fission and remodelling contributes to muscle atrophy , 2010, The EMBO journal.

[47]  A. M. van der Bliek,et al.  Dynamin-related protein Drp1 is required for mitochondrial division in mammalian cells. , 2001, Molecular biology of the cell.

[48]  B. Viollet,et al.  AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1 , 2011, Nature Cell Biology.

[49]  Takuya Miyakawa,et al.  Mitochondrial DNA Mutations Induce Mitochondrial Dysfunction, Apoptosis and Sarcopenia in Skeletal Muscle of Mitochondrial DNA Mutator Mice , 2010, PloS one.

[50]  D. Freyssenet,et al.  Contractile activity-induced adaptations in the mitochondrial protein import system. , 1998, The American journal of physiology.

[51]  Jiandie D. Lin,et al.  Transcriptional co-activator PGC-1α drives the formation of slow-twitch muscle fibres , 2002, Nature.

[52]  T. Prolla,et al.  Evaluation of sex differences on mitochondrial bioenergetics and apoptosis in mice , 2007, Experimental Gerontology.

[53]  T. Lamark,et al.  Selective autophagy mediated by autophagic adapter proteins , 2011, Autophagy.

[54]  T. Reynolds,et al.  PKB signaling and atrogene expression in skeletal muscle of aged mice. , 2011, Journal of applied physiology.

[55]  I. Bossis,et al.  Aging: Central role for autophagy and the lysosomal degradative system , 2009, Ageing Research Reviews.

[56]  U. Brunk,et al.  Oxidative stress, accumulation of biological 'garbage', and aging. , 2006, Antioxidants & redox signaling.

[57]  Michael F. N. O'Leary,et al.  Adaptive plasticity of autophagic proteins to denervation in aging skeletal muscle. , 2013, American journal of physiology. Cell physiology.

[58]  C. Fraga,et al.  Enalapril and losartan attenuate mitochondrial dysfunction in aged rats , 2003, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[59]  J. Aiken,et al.  Age-associated changes in function, structure and mitochondrial genetic and enzymatic abnormalities in the Fischer 344 x Brown Norway F(1) hybrid rat heart. , 2002, Journal of molecular and cellular cardiology.

[60]  M. Pfaffl,et al.  A new mathematical model for relative quantification in real-time RT-PCR. , 2001, Nucleic acids research.

[61]  T. D. Pugh,et al.  Mitochondrial DNA Mutations, Oxidative Stress, and Apoptosis in Mammalian Aging , 2005, Science.

[62]  M. Beal,et al.  Mitochondrial DNA deletions in human brain: regional variability and increase with advanced age , 1992, Nature Genetics.

[63]  M. Manjanatha,et al.  Accumulation of point mutations in mitochondrial DNA of aging mice. , 2003, Mutation research.

[64]  V. Mootha,et al.  Mechanisms Controlling Mitochondrial Biogenesis and Respiration through the Thermogenic Coactivator PGC-1 , 1999, Cell.

[65]  福家 聡,et al.  DNA deletions and clonal mutations drive premature aging in mitochondrial mutator mice , 2008 .

[66]  B. Spiegelman,et al.  Increased muscle PGC-1α expression protects from sarcopenia and metabolic disease during aging , 2009, Proceedings of the National Academy of Sciences.

[67]  L. Larsson,et al.  Skeletal muscle metabolism and ultrastructure in relation to age in sedentary men. , 1978, Acta physiologica Scandinavica.

[68]  J. Blesa,et al.  NRF-2 transcription factor is essential in promoting human Tomm70 gene expression. , 2004, Mitochondrion.

[69]  B. Spiegelman,et al.  AMP-activated protein kinase (AMPK) action in skeletal muscle via direct phosphorylation of PGC-1alpha. , 2007, Proceedings of the National Academy of Sciences of the United States of America.

[70]  H. Westerblad,et al.  Increased mitochondrial mass in mitochondrial myopathy mice , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[71]  C. Leeuwenburgh,et al.  New insights into the role of mitochondria in aging: mitochondrial dynamics and more , 2010, Journal of Cell Science.