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Free keywords:
Acetylcysteine/pharmacology
Animals
Cell Differentiation/genetics
DNA, Mitochondrial/*genetics/metabolism
Electron Transport
Erythropoiesis
Hematopoietic Stem Cells/*cytology/drug effects/metabolism
Lymphopoiesis
Mice
Mice, Mutant Strains
Mitochondrial Diseases/pathology
Mutagenesis
Neural Stem Cells/*cytology/drug effects/metabolism
Oxidation-Reduction
Phenotype
Reactive Oxygen Species/metabolism
Abstract:
Somatic stem cell (SSC) dysfunction is typical for different progeroid phenotypes in mice with genomic DNA repair defects. MtDNA mutagenesis in mice with defective Polg exonuclease activity also leads to progeroid symptoms, by an unknown mechanism. We found that Polg-Mutator mice had neural (NSC) and hematopoietic progenitor (HPC) dysfunction already from embryogenesis. NSC self-renewal was decreased in vitro, and quiescent NSC amounts were reduced in vivo. HPCs showed abnormal lineage differentiation leading to anemia and lymphopenia. N-acetyl-L-cysteine treatment rescued both NSC and HPC abnormalities, suggesting that subtle ROS/redox changes, induced by mtDNA mutagenesis, modulate SSC function. Our results show that mtDNA mutagenesis affected SSC function early but manifested as respiratory chain deficiency in nondividing tissues in old age. Deletor mice, having mtDNA deletions in postmitotic cells and no progeria, had normal SSCs. We propose that SSC compartment is sensitive to mtDNA mutagenesis, and that mitochondrial dysfunction in SSCs can underlie progeroid manifestations.
