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High-abundance mRNAs in human muscle: comparison between young and old
S Welle1, K Bhatt, C A Thornton
1Departments of Medicine, Pharmacology and Physiology, and Neurology, University of Rochester, Rochester, New York 14642, USA. stephen_welle@urmc.rochester.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 25, 2000
Summary
Aging muscle shows reduced gene expression for key proteins involved in energy production and glucose metabolism. These changes in gene transcription may contribute to the decline in muscle function observed in older adults.
Area of Science:
- Molecular Biology
- Gerontology
- Skeletal Muscle Physiology
Background:
- Muscle function declines with age, a process known as senescence.
- Altered gene expression is a potential contributor to age-related muscle dysfunction.
Purpose of the Study:
- To investigate differences in gene expression between young and old human vastus lateralis muscle.
- To identify specific transcripts affected by aging that may impact muscle function.
Main Methods:
- Serial Analysis of Gene Expression (SAGE) was used to analyze pooled muscle RNA from young and old individuals.
- Quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) validated SAGE findings in individual muscle samples.
Main Results:
- 89 out of 702 detected SAGE tags showed significant differences in expression between young and old muscle (P < 0.01).
- Reduced ratios of myosin heavy chain 2a mRNA to myosin heavy chain 1 mRNA were observed in older muscle.
- MRNAs for mitochondrial electron transport proteins (cytochrome-c oxidase, NADH dehydrogenase) and ATP synthase subunits were ~30% less abundant in older muscle.
- Several mRNAs for glucose metabolism enzymes were also less abundant in older muscle.
Conclusions:
- Aging is associated with decreased transcription of genes critical for mitochondrial function and glucose metabolism in skeletal muscle.
- These age-related changes in gene expression likely contribute to the diminished muscle function observed in older individuals.
- Findings suggest that altered gene transcription plays a significant role in muscle senescence.