Unknown,Transcriptomics,Genomics,Proteomics

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Gene expression profiling in skeletal muscle 3 hours following the performance of an eccentric exercise

ABSTRACT: Eccentric exercise (ECC) can result in ultra-structural and histological damage to skeletal muscle. The damage incurred following ECC is typically followed by a subsequent regenerative and adaptive response. The specific mechanisms that drive this response, particularly in human muscle, are not well understood. The objective of this study was to characterize the early molecular response in skeletal muscle following ECC in humans. We used an Agilent whole human genome microarray to assess global gene expression in male subjects (N=35) at 3 hours post-100 eccentric contractions of the knee extensors. ANCOVA (age and BMI covariates) was used to compare mRNA expression between the ECC and non-exercised (CON) legs of each subject. Novel transcripts from IPA identified networks were confirmed with quantitative real-time (qRT)-PCR. qRT-PCR analysis of 3 of these transcripts (IkBÎ±, TNFRSF1A and ICAM-1) confirmed changes observed in the microarray analysis. 35 male subjects performed an eccentric exercise protocol consisting of 100 maximal eccentric contrations of the knee extensors. 3 hours after the completion of the exercise regimen, a muscle biopsy was taken from the vastus lateralis of both legs. The non-exercised leg served as the control. Gene expresssion was analyzed using an ANCOVA, with covariates for age and BMI.

ORGANISM(S): Homo sapiens

SUBMITTER: Robert Hyldahl

PROVIDER: E-GEOD-23697 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Mice were subjected to 50 eccentric contractions (EC) or 50 isometric contractions (IC) using a non-invasive model, and then sacrificed 48 hours later. RNA from the tibialis anterior of 4 animals were pooled and then split into two groups for hybridization onto two separate Affymetrix MGU74Av2 chips. Control samples were contralateral to the exercised legs, and were only subjected to enough contractions to measure isometric torque. Eccentric contractions (ECs), in which a muscle is forced to lengthen while activated, result in muscle injury and, eventually, muscle strengthening and prevention of further injury. Although the mechanical basis of eccentric contraction-induced injury has been studied in detail, muscle's biological response is less well characterized. This study presents the development of a minimally-invasive model of EC injury in the mouse, follows the time course of torque recovery after an injurious bout of ECs, and uses Affymetrix microarrays to compare the gene expression profile 48 hours after ECs to both isometrically stimulated muscles and contralateral muscles. Torque dropped by about 55% immediately after the exercise bout, and recovered to initial levels 7 days later. 36 known genes were upregulated after ECs compared to contralateral and isometrically stimulated muscles, including five muscle specific genes: muscle LIM protein (MLP), Muscle Ankyrin Repeat Proteins (MARP 1 and 2; also known as cardiac ankyrin repeat protein and Arpp/Ankrd2, respectively), Xin, and Myosin Binding Protein H. The time courses of MLP and MARP expression after the injury bout (determined by quantitative real-time polymerase chain reaction) indicate that these genes are rapidly induced, reaching a peak expression level of 6-11 times contralateral values 12-24 hours after the EC bout and returning to baseline within 72 hours. Very little gene induction was seen after either isometric activation or passive stretch, indicating that the MLP and MARP genes may play an important and specific role in the biological response of muscle to EC-induced injury. Keywords = mouse tibialis anterior eccentric contraction muscle

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Gene expression profiling in skeletal muscle 3 hours following the performance of an eccentric exercise

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