Overcoming muscle atrophy during prolonged disuse in hibernation: iTRAQ-based quantitative proteomic

• 作 者: Hui CHANG Yun-Fang GAO
• 机 构: Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Nor
• 出 处: 第四届中国西部动物学学术研讨会
• 发表日期: 2015年11期
• 关键词: Daurian ground squirrel Hibernation Protein metabolism Proteomic Disuse atrophy

　　Hibernators like Daurian ground squirrels (Spermophilus dauricus) appear to deviate from significant increase of protein catabolism and loss of myofibrillar contents during long period of hibernation inactivity, which provides a useful model to study mechanisms of preventing disuse-induced skeletal muscle atrophy.We explored proteomic assessment of soleus muscle (SOL) in hibernating Daurian ground squirrels to test a hypothesis that expression levels of major myofibrillar proteins are retained during hibernation, with inhibition of protein degradation as a key potential mechanism to prevent disuse atrophy.Here we use iTRAQ-based quantitative analysis to examine proteomic changes in myofibrillar contents and proteolytic pathways from the SOL of squirrels in non hibernation/pre-hibernation (PRE) and hibernation (HB) states.We found the SOL in squirrels showed limited sign of atrophy over 60-day winter dormancy.Levels of most cytoskeletal and contractile proteins examined were maintained through hibernation period, with 2 cytoskeletal proteins (vimentin and calreticulin) and 2 contractile proteins (myosin-2 and troponin C) 1.2-to 2.l-fold upregulated in HB compared to PRE, whereas 2 cytoskeletal proteins (fibrinogen and tropomodulin) and 1 contractile protein (myosin-3) were respectively reduced by 46%, 30%, 41% in HB compared to PRE.Moreover, expression levels of six protease subunits from ubiquitin-proteasome proteolytic pathway were 1.2-to 1.5-fold higher in HB than in PRE, meanwhile, the level of catalase from lysosomal proteolytic pathway was 1.2-fold higher in HB than in PRE, however consistent with our previous study, proteomics showed that calpain proteolytic pathway did not change significantly in hibernation.Thus, partial suppression of myofibrillar proteolysis was likely responsible for preventing skeletal muscle atrophy during prolonged disuse in hibernation.