iTRAQ-coupled 2D LC-MS/MS analysis on differentially expressed proteins in denervated tibialis anterior muscle of Rattus norvegicus.

To understand the molecular aspects of denervation-induced atrophy of skeletal muscles, isobaric tags for relative and absolute quantitation (iTRAQ) coupled with two-dimensional liquid chromatography-tandem mass spectrometry were performed to detect a total of 260 proteins that were differentially expressed in the rat tibialis anterior muscle at different times (1, 4, and 8 weeks) after rat sciatic nerve transection. Western blot, gene ontology, and Kyoto Encyclopedia of Genes and Genomes analyses were further conducted for protein validation, functional annotation, and pathway identification, respectively. Among 260 dysregulated proteins, metabolic enzymes represented the largest class of proteins differentially expressed; a down-regulation of β-enolase might be associated with a decreased expression of fast-twitch myosin-4; the 14-3-3 proteins displayed an up-regulation, which might facilitate the inhibition of mTOR signaling; an up-regulation of α-crystallin B chain might be related to the later onset and the slower progress of atrophy; an up-regulation of phosphatidylethanolamine-binding protein-1 perhaps progressively abrogated the cell survival and antiapoptotic properties during muscle atrophy. These results might contribute to the understanding of molecular mechanisms regulating denervation-induced muscle atrophy.