Frailty represents the summation of the effects of motor neuron degeneration, muscle fiber denervation and degeneration, decreased muscle mass and strength, and mitochondrial dysfunction, but the cause-effect relationships among these variables are unknown. The primary long term goal of the Program Project is to understand the mechanisms underlying the age-related deterioration of motor nerves, muscle fibers, and mitochondria responsible for physical frailty. During our previous five years of support, dozens of knockout (KO) and over-expressor adult and old mice were investigated and superoxide-mediated oxidative stress was identified as a key factor in the age-related changes in the neuromuscular system. The Sod1-/- mouse was identified as the most promising animal model to test hypotheses regarding the role of oxidative stress in the age-related changes in nerves, neuromuscular junctions, muscle fibers, and mitochondria. In addition, CuZnSOD activity was rescued separately in nerves, Sod1-/-(N) mice, and muscles, Sod1-/-(M) mice, to address additional hypotheses related to the specific tissues in which oxidative stress is critical to the age-related changes. The three research groups in Ann Arbor, Liverpool and San Antonio have demonstrated their ability to collaborate with numerous meetings and the publication of major co-authored papers linking their expertise in physiology, biochemistry, molecular and cell biology, and bioengineering in the studies of the structure and function of muscles and mitochondria. The addition of Eva Feldman to Project 1 adds a further dimension in the fields of neurobiology and neurology for studies of the timing and interactions among age-related changes motor neurons, muscle fibers, and mitochondria. The Transgenic Animal Core in San Antonio has linked with that in Ann Arbor to facilitate the provision of KO and transgenic mice. The overall working hypothesis of the Program Project is that impaired regulation of superoxide in the Sod1-/- mouse leads to increased oxidative stress and damage in motor neurons, skeletal muscle fibers and mitochondria that cause acceleration in the development of age-related muscle atrophy and weakness. Testing this working hypothesis will provide insights into the underlying mechanisms associated with 'frailty'and 'failure to thrive'of elderly humans. The investigators in the three Projects have the diverse, well-established investigative skills, productivity, and proven ability in long term collaborations necessary to undertake this challenging task. The relevance to public health of the PPG lies in its focus on the major public health problem among the elderly of 'frailty and failure to thrive', estimated to cost $90 billion per year. Geriatricians cite a lack of understanding of the mechanisms underlying frailty as a major factor contributing to the lack of progress in the treatment of the condition. The scientific outcomes of this PPG should provide substantial scientific insights regarding the underlying causes of the condition and possible treatments.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
5P01AG020591-07
Application #
7614472
Study Section
Special Emphasis Panel (ZAG1-ZIJ-5 (J4))
Program Officer
Williams, John
Project Start
2002-05-01
Project End
2013-04-30
Budget Start
2009-05-01
Budget End
2010-04-30
Support Year
7
Fiscal Year
2009
Total Cost
$1,190,287
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Physiology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Snider, Timothy A; Richardson, Arlan; Stoner, Julie A et al. (2018) The Geropathology Grading Platform demonstrates that mice null for Cu/Zn-superoxide dismutase show accelerated biological aging. Geroscience 40:97-103
Zhang, Yiqiang; Unnikrishnan, Archana; Deepa, Sathyaseelan S et al. (2017) A new role for oxidative stress in aging: The accelerated aging phenotype in Sod1-/- mice is correlated to increased cellular senescence. Redox Biol 11:30-37
Deepa, Sathyaseelan S; Bhaskaran, Shylesh; Espinoza, Sara et al. (2017) A new mouse model of frailty: the Cu/Zn superoxide dismutase knockout mouse. Geroscience 39:187-198
Pollock, Natalie; Staunton, Caroline A; Vasilaki, Aphrodite et al. (2017) Denervated muscle fibers induce mitochondrial peroxide generation in neighboring innervated fibers: Role in muscle aging. Free Radic Biol Med 112:84-92
Vasilaki, Aphrodite; Pollock, Natalie; Giakoumaki, Ifigeneia et al. (2016) The effect of lengthening contractions on neuromuscular junction structure in adult and old mice. Age (Dordr) 38:259-272
Sloboda, Darcée D; Brooks, Susan V (2016) Treatment with selectin blocking antibodies after lengthening contractions of mouse muscle blunts neutrophil accumulation but does not reduce damage. Physiol Rep 4:
Zhang, Yiqiang; Liu, Yuhong; Walsh, Michael et al. (2016) Liver specific expression of Cu/ZnSOD extends the lifespan of Sod1 null mice. Mech Ageing Dev 154:1-8
Sakellariou, Giorgos K; Pearson, Timothy; Lightfoot, Adam P et al. (2016) Mitochondrial ROS regulate oxidative damage and mitophagy but not age-related muscle fiber atrophy. Sci Rep 6:33944
Sakellariou, Giorgos K; Pearson, Timothy; Lightfoot, Adam P et al. (2016) Long-term administration of the mitochondria-targeted antioxidant mitoquinone mesylate fails to attenuate age-related oxidative damage or rescue the loss of muscle mass and function associated with aging of skeletal muscle. FASEB J 30:3771-3785
Jackson, Malcolm J (2016) Reactive oxygen species in sarcopenia: Should we focus on excess oxidative damage or defective redox signalling? Mol Aspects Med 50:33-40

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