Aminoglycoside stress together with the 12S rRNA 1494C>T mutation leads to mitophagy

Area of Science:

• Mitochondrial biology
• Genetics
• Toxicology

Background:

• Mitochondrial rRNA mutations can cause hearing loss.
• Aminoglycosides (AGs) are known to affect mitochondrial function.
• The interaction between specific mutations and AGs is not fully understood.

Purpose of the Study:

• To investigate how the m.1494C>T mitochondrial rRNA mutation affects mitochondrial function.
• To determine the impact of gentamycin exposure on cells with the m.1494C>T mutation.
• To elucidate the cellular response to combined mitochondrial stress and gentamycin.

Main Methods:

• Utilized cybrid cell models harboring the m.1494C>T mutation.
• Assessed mitochondrial dysfunction, including ATP production and reactive oxygen species (ROS) levels.
• Analyzed mitochondrial membrane potential and mitophagy markers (LC3-B) after gentamycin exposure.

Main Results:

• The m.1494C>T mutation significantly reduced mtDNA-encoded proteins and ATP production, increasing ROS.
• Gentamycin exacerbated mitochondrial dysfunction in mutant cybrids, decreasing ATP production and membrane potential.
• Combined stress induced mitochondrial fusion and mitophagy as a protective response, rather than apoptosis.

Conclusions:

• Gentamycin aggravates mitochondrial dysfunction associated with the m.1494C>T mutation.
• The study provides insights into the interplay between mitochondrial mutations, AG toxicity, and hearing loss.
• Mitophagy acts as a compensatory mechanism against combined mitochondrial stress.