Mitochondrial DNA Mutations and Age-Related Muscle Loss

What are Mitochondria?

Definition: Mitochondria are membrane-bound organelles present in the cytoplasm of most eukaryotic cells, often called the “powerhouses” of the cell.
Maternal inheritance: Mitochondria are inherited exclusively from the mother via the egg cell.

Key functions:

Energy production: Generate adenosine triphosphate (ATP), the primary energy carrier required for muscle contraction, protein synthesis, and cell division.
Cellular respiration: Facilitates the breakdown of food into energy in the form of ATP.
Regulating cell death: Control apoptosis, ensuring the maintenance of healthy tissues.
Mitochondrial DNA (mtDNA): Contains its DNA, which is prone to mutations that significantly affect cellular functions.

Key Findings of the Study

Deletion mutation’s role: Deletion mutations in mtDNA reduce its size and functionality, gradually eroding mitochondrial efficiency.
- These mutated mtDNA molecules outcompete healthy ones, leading to a decline in ATP production.
Chimeric genes: Deletion mutations create chimeric genes by fusing different mitochondrial genes, forming abnormal sequences.
- Chimeric genes disrupt mtDNA expression, accelerating mitochondrial dysfunction and muscle degradation.
Age-related changes: Older individuals exhibit a two-fold increase in chimeric mitochondrial mRNA, correlating with biological ageing.
- Mutations also affect brain and muscle tissues, emphasizing their systemic impact on ageing.
Biomarkers for biological ageing: mtDNA deletion mutations and chimeric mRNA are key indicators of biological ageing.
- Understanding these markers could pave the way for therapies to prevent or repair mutations, delaying age-related muscle loss.