Study on 4 weeks medium intensity aeraobic exercise induce the difference expression of the proteomics in rat atrial muscle / 中国应用生理学杂志

OBJECTIVE@#To investigate the effect of moderate-intensity aerobic exercise on the differential expression of rat atrial muscle Proteomics and genes, which provide research basis for the rehabilitation of chronic cardiovascular diseases and exercise -induced cardiac remodeling research.@*METHODS@#Twenty male SD rats were randomly divided into control group and experimental group (=10) according to body weight. Rats in the experimental group were trained (6 days per week),which lasted for 4 weeks of moderate-intensity aerobic exercise at a rate of 24 m·min for 40 min (load intensity equivalent to 60%~70% VO). The proteins were separated by two dimensional gel electrophoresis, and the tandem time-of- flight mass spectrometer technique was used to identify 13 candidate target protein spots. The expression levels of these 13 protein spots were up-regulated more than 5 times or down -regulated to below 1/5. The mRNA of six target proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR).@*RESULTS@#By software analysis, the experimental group compared with the control group, there were 8 protein points which their expression reduced more than 4/5 and 5 protein points up-regulated more than 5 times, 13 proteins were identified by mass spectrometry protein spots, the final identification results acquired 8 proteins and a unknown protein of molecular mass 54 KDa, such as:pyruvate dehydrogenase E1α1, mitochondrial aconitate hydratase, protein disulfide isomerase A3, methylmalonic acid semialdehyde dehydrogenase, mitochondrial dihydrolipoic acid dehydrogenase, isovaleryl coenzyme A dehydrogenase, glutathione synthetase, mitogen-activated protein kinase 3 and so on. Compared with the control group, the mRNA expression of methylmalonic acid semialdehyde dehydrogenase in the atrial muscle of rats was decreased after 4 weeks of moderate aerobic exercise (0.05); The mRNA expression level of isopentenyl-CoA dehydrogenase was increased (>0.05). The results indicated that the mRNA expression level was not completely consistent with the changes in mass spectrometry identification results.@*CONCLUSIONS@#The 4 weeks moderate-intensity aerobic exercise induced ignificant changes of rats atrial muscle protemics. The majority of the 13 identified target proteins in this experiment are energy metabolism enzymes. The majority of the expression of the target protein and the mRNA expression in the atrial muscle is inconsistent and different. Exercise may affect the regulation of gene transcription or downstream translation and modification of these target proteins, resulting in the change of differential expression.

Selumetinib Attenuates Skeletal Muscle Wasting in Murine Cachexia Model through ERK Inhibition and AKT Activation.

Cancer cachexia is a multifactorial syndrome affecting the skeletal muscle. Previous clinical trials showed that treatment with MEK inhibitor selumetinib resulted in skeletal muscle anabolism. However, it is conflicting that MAPK/ERK pathway controls the mass of the skeletal muscle. The current study investigated the therapeutic effect and mechanisms of selumetinib in amelioration of cancer cachexia. The classical cancer cachexia model was established via transplantation of CT26 colon adenocarcinoma cells into BALB/c mice. The effect of selumetinib on body weight, tumor growth, skeletal muscle, food intake, serum proinflammatory cytokines, E3 ligases, and MEK/ERK-related pathways was analyzed. Two independent experiments showed that 30 mg/kg/d selumetinib prevented the loss of body weight in murine cachexia mice. Muscle wasting was attenuated and the expression of E3 ligases, MuRF1 and Fbx32, was inhibited following selumetinib treatment of the gastrocnemius muscle. Furthermore, selumetinib efficiently reduced tumor burden without influencing the cancer cell proliferation, cumulative food intake, and serum cytokines. These results indicated that the role of selumetinib in attenuating muscle wasting was independent of cancer burden. Detailed analysis of the mechanism revealed AKT and mTOR were activated, while ERK, FoxO3a, and GSK3ß were inhibited in the selumetinib -treated cachexia group. These indicated that selumetinib effectively prevented skeletal muscle wasting in cancer cachexia model through ERK inhibition and AKT activation in gastrocnemius muscle via cross-inhibition. The study not only elucidated the mechanism of MEK/ERK inhibition in skeletal muscle anabolism, but also validated selumetinib therapy as an effective intervention against cancer cachexia. Mol Cancer Ther; 16(2); 334-43. ©2016 AACR.