Mitochondrial biogenesis is a target of many aging interventions. While the induction of mitochondrial biogenesis is generally thought to be beneficial, our data indicate that activating mitochondrial biogenesis at old age drives the intracellular accumulation of mitochondrial DNA (mtDNA) deletion mutations and results in an 18% loss of muscle fibers and a 1,200% increase in electron transport chain (ETC) deficient muscle fiber segments. These effects were antagonistically pleiotropic; they were not observed in treated young rats. Based on our data, up-regulation of mitochondrial biogenesis in aged humans may cause significant skeletal muscle damage. These studies will clarify the role of mitochondrial biogenesis in mtDNA deletion mutation accumulation and evaluate the old-age specific effects of compounds that stimulate mitochondrial biogenesis in skeletal muscle. This project will: define the antagonistic pleiotropy of mitochondrial biogenesis in muscle fiber loss; test the hypothesis that mtDNA deletion genome accumulation drives fiber loss; specify the order of events and time required between mitochondrial biogenesis, mtDNA deletion mutation accumulation and cell death; refine proposed mechanisms for deletion accumulation; determine if geroprotectors, which target mitochondrial biogenesis, antagonistically induce mtDNA deletion mutation accumulation. By understanding the mechanisms of inducing mitochondrial biogenesis at old ages, we will specify targets and treatment strategies that mitigate the antagonistic effects. This K02 award, if funded, will protect the candidate's research time from overextended clinical and administrative duties to allow further research development.

Public Health Relevance

A significant contributor to aging is the chronic loss of individual cells throughout the lifespan. With age, 46 percent of the muscle cells are lost, leading to frailty, a rapidly growing challenge to aging Americans. These studies will test mechanisms and explore interventions that affect the accumulation of mutations within the mitochondrial genome, muscle cell loss and muscle function.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02AG059847-02
Application #
9767003
Study Section
Neuroscience of Aging Review Committee (NIA)
Program Officer
Fridell, Yih-Woei
Project Start
2018-09-01
Project End
2023-05-31
Budget Start
2019-06-01
Budget End
2020-05-31
Support Year
2
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095