title: Mitochondrial maintenance failure in aging and role of sexual dimorphism.
abstract: Gene expression changes during aging are partly conserved across species, and suggest that oxidative stress, inflammation and proteotoxicity result from mitochondrial malfunction and abnormal mitochondrial-nuclear signaling. Mitochondrial maintenance failure may result from trade-offs between mitochondrial turnover versus growth and reproduction, sexual antagonistic pleiotropy and genetic conflicts resulting from uni-parental mitochondrial transmission, as well as mitochondrial and nuclear mutations and loss of epigenetic regulation. Aging phenotypes and interventions are often sex-specific, indicating that both male and female sexual differentiation promote mitochondrial failure and aging. Studies in mammals and invertebrates implicate autophagy, apoptosis, AKT, PARP, p53 and FOXO in mediating sex-specific differences in stress resistance and aging. The data support a model where the genes Sxl in Drosophila, sdc-2 in Caenorhabditis elegans, and Xist in mammals regulate mitochondrial maintenance across generations and in aging. Several interventions that increase life span cause a mitochondrial unfolded protein response (UPRmt), and UPRmt is also observed during normal aging, indicating hormesis. The UPRmt may increase life span by stimulating mitochondrial turnover through autophagy, and/or by inhibiting the production of hormones and toxic metabolites. The data suggest that metazoan life span interventions may act through a common hormesis mechanism involving liver UPRmt, mitochondrial maintenance and sexual differentiation.
authors.affiliation: Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, United States. Electronic address: jtower@usc.edu.
authors.forename: John
authors.initials: J
authors.lastname: Tower
mesh_terms: D000375:Aging; D000818:Animals; D001343:Autophagy; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D008136:Longevity; D008928:Mitochondria / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D012727:Sex Characteristics; D056811:Unfolded Protein Response
keywords: Dosage compensation; Heteroplasmy; Mother’s curse; Sexual antagonistic pleiotropy; Sexual conflict; UPRmt