Project description:Genome-wide H3S10ph marks from mouse gastrocnemius muscles after 50 eccentric contractions compared to contralateral unstimulated gastrocnemius muscles from the same mice.
Project description:Duchenne muscular dystrophy (DMD) is an X-linked recessive disease caused by deleterious mutations in the DMD gene, rendering non-functional forms or complete absence of the protein dystrophin. Eccentric contraction-induced force loss is the most robust and reproducible phenotype of dystrophin-deficient skeletal muscle, yet the molecular mechanisms underlying force loss remain obscure. To this end, we utilized the mdx mouse model of DMD, which displays extreme sensitivity to eccentric contractions. An existing mouse line from our lab that overexpresses cytoplasmic gamma-actin specifically in skeletal muscle (mdx/Actg1-TG) was shown to significantly protect mdx muscle against contraction-induced force loss. To understand the mechanism behind this protection, we performed iTRAQ proteomics on mdx/Actg1-TG tibialis anterior (TA) muscle versus non-transgenic littermate controls to identify differentially-expressed proteins that may afford protection upon gamma-actin overexpression.
Project description:We examined global mRNA expression using cDNA microarrays in skeletal muscle of humans before, and 3h and 48h after 300 maximal eccentric contractions. Keywords: Time course
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
Project description:We examined global mRNA expression using cDNA microarrays in skeletal muscle of humans before, and 3h and 48h after 300 maximal eccentric contractions. Keywords: Time course Healthy, non-trained university-aged subjects performed 300 single leg maximal eccentric contractions. Skeletal muscle biopsies were taken from the vastus lateralis before, 3h and 48h after the exercise bout. Total RNA was extracted, amplified, reverse transcribed, and cDNA was analyzed on a custom made cDNA microarray. Four subjects were analyzed, and samples were not pooled between subjects (i.e. individual microarrays were used for baseline vs. 3H and baseline vs. 48h for EACH subject; repeated measures design).
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 isometric contraction muscle Keywords: other
Project description:Desmin is a cytoskeletal protein in muscle involved in integrating cellular space and transmitting forces. In this study we sought to determine the combinatory effects of desmin deletion, aging and eccentric exercise on skeletal muscle at the transcriptional level across many pathways of muscle physiology. RNA was isolated from the TA muscle of mice of two genotypes (wildtype (WT) and desmin knockout (KO)) and two ages (7-9 weeks (Adult) and 12-14 months (Aged)). TA muscles were subjected to a bout of 50 eccentric contractions 12 hours prior to RNA isolation. Numbers per group are as follows: WT_Adult (5), WT_Aged (5), KO_Adult (5), KO_Aged (4).
Project description:We generated a large transcriptome atlas of human skeletal muscles by collecting biopsies from 6 different muscles to determine molecular signatures that may be distinct between leg muscles. The biopsies were collected from gracilis (GR), semitendinosus (ST), vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), and gastrocnemius lateralis (GL) muscles. We also investigated molecular differences within the muscle by including two biopsies from the middle and distal sides of the semitendinosus muscle (STM and STD, respectively). In total, 128 samples from 20 individuals (aged 25 ± 3.6 yr) were analyzed.
Project description:Background: Niemann-Pick disease type A (NPDA), a disease caused by mutations in acid sphingomyelinase (ASM), involves severe neurodegeneration and early death. Intracellular lipid accumulation and plasma membrane alterations are implicated in the pathology. ASM is also linked to the mechanism of plasma membrane repair, so we investigated the impact of ASM deficiency in skeletal muscle, a tissue that undergoes frequent cycles of injury and repair in vivo. Methods: Utilizing the NPDA/B mouse model ASM−/− and wild type (WT) littermates, we performed excitation- contraction coupling/Ca2+ mobilization and sarcolemma injury/repair assays with isolated flexor digitorum brevis fibers, proteomic analyses with quadriceps femoris, flexor digitorum brevis, and tibialis posterior muscle and in vivo tests of the contractile force (maximal isometric torque) of the quadriceps femoris muscle before and after eccentric contraction-induced muscle injury. Results: ASM−/− flexor digitorum brevis fibers showed impaired excitation-contraction coupling compared to WT, a defect expressed as reduced tetanic [Ca2+]i in response to electrical stimulation and early failure in sustaining [Ca2+]i during repeated tetanic contractions. When injured mechanically by needle passage, ASM−/− flexor digitorum brevis fibers showed susceptibility to injury similar to WT, but a reduced ability to reseal the sarcolemma. Proteomic analyses revealed changes in a small group of skeletal muscle proteins as a consequence of ASM deficiency, with downregulation of calsequestrin occurring in the three different muscles analyzed. In vivo, the loss in maximal isometric torque of WT quadriceps femoris was similar immediately after and 2 min after injury. The loss in ASM−/− mice immediately after injury was similar to WT, but was markedly larger at 2 min after injury. Conclusions: Skeletal muscle fibers from ASM−/− mice have an impairment in intracellular Ca2+ handling that results in reduced Ca2+ mobilization and a more rapid decline in peak Ca2+ transients during repeated contraction-relaxation cycles. Isolated fibers show reduced ability to repair damage to the sarcolemma, and this is associated with an exaggerated deficit in force during recovery from an in vivo eccentric contraction- induced muscle injury. Our findings uncover the possibility that skeletal muscle functional defects may play a role in the pathology of NPDA/B disease.
Project description:Male skeletal muscles are generally faster and have a higher maximum power output than female muscles. Conversely, during repeated contractions female muscles sre generally more fatigue resistant and recover faster. we hypothesized that estrogen receptor beta is involved in this gender difference. The Affymetrix micorarray were used to deteced the differently expressed genes between male BERKO and WT mice in soleus muscles. Soleus muscles from 3 individual mouse of each genotype were used to perform the experiment. Keywords: repeat sample