Defining the transcriptomic profile of rat ageing skeletal muscle using cDNA array, 2D- and Blue Native-PAGE

We defined the transcriptomic and proteomic profiles of rat ageing skeletal muscle using acombined cDNA array, 2D- and Blue native-PAGE approach. This was allowed to obtain anoverview of the interrelated events leading to the transcriptome/proteome/mitoproteomechanges likely to underlie the structural/metabolic features of aged skeletal muscle. The maindifferences were found in genes/proteins related to energy metabolism, mitochondrialpathways, myofibrillar filaments, and detoxification. Concerning the abundance ofmitochondrial OXPHOS complexes as well as their supramolecular organization and activity,mitochondria fromold rats,when compared with those from young rats, contained significantlylower amounts of complex I (NADH:ubiquinone oxidoreductase), V (FoF1-ATP synthase), and III(ubiquinol:cytochrome c oxidoreductase). The same mitochondria contained a significantlylarger amount of complex II (succinate:ubiquinone oxidoreductase), but an unchanged amountof complex IV(cytochrome c oxidase,COX).Whencomparing the supercomplex profiles betweenyoung and old muscle mitochondria, the densitometric analysis revealed that lightersupercomplexes were significantly reduced in older mitochondria, and that in the older groupthe major supercomplex bands were those representing heavier supercomplexes, likelysuggesting a compensatory mechanism that, in ageing muscle, is functionally directedtowards substrate channeling and catalytic enhancement advantaging the respirosome.