title: A correlation of reactive oxygen species accumulation by depletion of superoxide dismutases with age-dependent impairment in the nervous system and muscles of Drosophila adults.
abstract: The theory that accumulation of reactive oxygen species (ROS) in internal organs is a major promoter of aging has been considered negatively. However, it is still controversial whether overexpression of superoxide dismutases (SODs), which remove ROS, extends the lifespan in Drosophila adults. We examined whether ROS accumulation by depletion of Cu/Zn-SOD (SOD1) or Mn-SOD (SOD2) influenced age-related impairment of the nervous system and muscles in Drosophila. We confirmed the efficient depletion of Sod1 and Sod2 through RNAi and ROS accumulation by monitoring of ROS-inducible gene expression. Both RNAi flies displayed accelerated impairment of locomotor activity with age and shortened lifespan. Similarly, adults with nervous system-specific depletion of Sod1 or Sod2 also showed reduced lifespan. We then found an accelerated loss of dopaminergic neurons in the flies with suppressed SOD expression. A half-dose reduction of three pro-apoptotic genes resulted in a significant suppression of the neuronal loss, suggesting that apoptosis was involved in the neuronal loss caused by SOD silencing. In addition, depletion of Sod1 or Sod2 in musculature is also associated with enhancement of age-related locomotion impairment. In indirect flight muscles from SOD-depleted adults, abnormal protein aggregates containing poly-ubiquitin accumulated at an early adult stage and continued to increase as the flies aged. Most of these protein aggregates were observed between myofibril layers. Moreover, immuno-electron microscopy indicated that the aggregates were predominantly localized in damaged mitochondria. These findings suggest that muscular and neuronal ROS accumulation may have a significant effect on age-dependent impairment of the Drosophila adults.
authors: Insect Biomedical Research Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-0962, Japan.
authors: Saori
authors: S
authors: Oka
authors: Jun
authors: J
authors: Hirai
authors: Takashi
authors: T
authors: Yasukawa
authors: Yasuyuki
authors: Y
authors: Nakahara
authors: Yoshihiro H
authors: YH
authors: Inoue
mesh_terms: D000367:Age Factors; D000375:Aging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D017209:Apoptosis; D059290:Dopaminergic Neurons / Q000378:metabolism / Q000473:pathology; D029721:Drosophila Proteins / Q000172:deficiency* / Q000235:genetics; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics; D005426:Flight, Animal; D005838:Genotype; D008136:Longevity; D008931:Mitochondria, Muscle / Q000378:metabolism / Q000473:pathology; D009043:Motor Activity; D009132:Muscles / Q000201:enzymology* / Q000473:pathology; D009420:Nervous System / Q000201:enzymology* / Q000473:pathology; D018384:Oxidative Stress; D010641:Phenotype; D066329:Protein Aggregates; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000172:deficiency* / Q000235:genetics; D000072105:Superoxide Dismutase-1; D015854:Up-Regulation; D000099156:Superoxide Dismutase 2
chemical_list: D029721:Drosophila Proteins; D066329:Protein Aggregates; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2