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Behavioral and metabolic characterization of heterozygous and homozygous POLG mutator mice

Ying Dai1, Tomas Kiselak, Joanne Clark

  • 1Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. ydai@bidmc.harvard.edu

Mitochondrion
|April 2, 2013
PubMed

Insights

Mitochondrial DNA (mtDNA) mutations in POLG mice impair motor function and metabolism. Older homozygous mice showed reduced dopaminergic terminals, while both genotypes exhibited decreased energy production, indicating mtDNA mutation significance.

Area of Science:

  • Neuroscience
  • Genetics
  • Mitochondrial Biology

Background:

  • Mitochondrial DNA (mtDNA) mutations are implicated in aging and disease.
  • The POLG mutator mouse model allows investigation of mtDNA mutation effects.
  • Somatic mtDNA mutations' functional significance requires experimental validation.

Purpose of the Study:

  • To investigate the functional impact of somatic mtDNA mutations in POLG mutator mice.
  • To assess age-related changes in dopaminergic function, motor behavior, and metabolism.
  • To determine the role of POLG-induced mtDNA mutations in these deficits.

Main Methods:

  • Utilized POLG mutator mice (homozygous and heterozygous) and age-matched controls.
  • Assessed striatal dopaminergic terminals using immunohistochemistry.
  • Evaluated motor function through behavioral tests.
  • Measured resting oxygen consumption, heat production, and mtDNA content.
  • Analyzed mitochondrial electron transport chain activities.

Main Results:

  • Older homozygous POLG mice exhibited significant reductions in striatal dopaminergic terminals.
  • Motor function deficits were observed in older homozygous POLG mice.
  • Resting oxygen consumption, heat production, mtDNA content, and ETC activities were decreased in both homozygous and heterozygous older POLG mice.

Conclusions:

  • High levels of somatic mtDNA mutations are functionally significant, contributing to dopaminergic dysfunction.
  • These mutations are linked to behavioral and metabolic deficits observed in aging.
  • The POLG mutator mouse model is valuable for studying mtDNA mutation-related pathologies.

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