Meeting Abstract

P2.131  Friday, Jan. 4  Reactive Oxygen Species May Stimulate Mitochondrial Biogenesis in Response to Cold Temperature in Aerobic Muscle of Threespine Stickleback HARTLEBEN, Goetz; TAWNEY, Rachel; O’BRIEN, Kristin*; University of Alaska, Fairbanks; University of Alaska, Fairbanks; University of Alaska, Fairbanks ffko@uaf.edu

Mitochondrial density increases in the aerobic muscle tissue of many fish species in response to a decrease in temperature and is critical for maintaining ATP production and muscle function. Surprisingly, little is known about the molecular pathway governing this process. We examined the role of reactive oxygen species (ROS) in mediating mitochondrial biogenesis in response to cold temperature in the threespine stickleback, Gasterosteus aculeatus. Fishes were shifted from 20&degC to 5&degC and maintained at this temperature for six weeks. Animals were harvested throughout the acclimation period and aerobic pectoral adductor muscle was isolated. Protein carbonyls and the expression of antioxidants were measured as indicators of ROS production. The expression of aerobically-poised enzymes was assessed as an indicator of mitochondrial biogenesis and expression of key regulatory factors of mitochondrial biogenesis (PGC-1, NRF-1 and Tfam) was quantified throughout the cold acclimation process. Levels of oxidized proteins increase within the first two days of cold acclimation and expression of both the CuZn and Mn superoxide dismutase increases by day three of cold acclimation. Transcript levels of NRF-1 and Tfam also increase by day three of cold acclimation. Expression of genes encoding aerobically-poised enzymes (CS, COXIV, CYC, HOAD) all begin to increase by day three of cold acclimation, but do not peak in expression until six weeks at 5&degC. These results suggest that ROS are produced early during the cold acclimation process in the aerobic muscle tissue of fishes and may play a role in stimulating mitochondrial biogenesis, which may not be complete within six weeks. This work was supported by AK EPSCoR and NSF grant 0643857 to K.O.