Project description:The satellite cell of skeletal muscle provides a paradigm for quiescent and activated tissue stem cell states. We have carried out transcriptome analyses by comparing satellite cells from adult skeletal muscles, where they are mainly quiescent, with cells from growing muscles, regenerating (mdx) muscles, or with cells in culture, where they are activated. Our study gives new insights into the satellite cell biology during activation and in respect with its niche. We used microarrays to study the global programme of gene expression underlying adult satellite cell quiescence compared to activation states and to identify distinct classes of up-regulated genes in these two different states Skeletal muscle satellite cells were isolated by flow cytrometry using the GFP fluorescence marker from Pax3GFP/+ mice skeletal muscle. The transcriptome of quiescent satellite cells from adult Pax3GFP/+ muscle was compared to the transcriptome of activated satellite cells obtained from three different samples: 1) regenerating Pax3GFP/+:mdx/mdx muscle (Ad.mdx) , 2) growing 1 week old Pax3GFP/+ muscle (1wk), and 3) adult Pax3GFP/+ cells after 3 days in culture (Ad.cult).
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:(Abstract of publication submitted currently) To clarify molecular regulation of satellite cells, we performed genome-wide gene expression analysis of quiescent satellite cells isolated from mouse skeletal muscle by flow cytometry. We identified 53 novel quiescent satellite cell-specific genes whose expressions are sharply down-regulated upon activation. The gene list contains a number of cell surface molecules, transcriptional factors, and cytokines and other signal transduction molecules. We further confirmed that Odz4 and calcitonin receptor proteins were expressed by quiescent but not by activated satellite cells in vivo. Importantly, we found that Pax7+/calcitonin receptor+ satellite cells reappear in close association with regenerating myofibers 7 days after muscle damage, often outside the basal lamina. Moreover, an agonist of calcitonin receptor suppressed the activation of quiescent satellite cells on myofibers in in vitro culture, suggesting that calcitonin receptor signaling plays an important role in renewal and maintenance of satellite cells. Our results show the gene expression profile of quiescent satellite cells for the first time and reveal the temporal and spatial reappearance of a satellite cell pool. Experiment Overall Design: Satellite cells and non-satellite cells were examined. Totally three types of cells (groups), the satellite cells in quiescent and activated states and the non-satellite cells, were compared. Each has 4 replicates.
Project description:We performed genome-wide gene expression analysis of quiescent/activated muscle stem cells isolated from mouse skeletal muscle by flow cytometry. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions or after cardiotoxin (CTX) injury (3 days). Pure satellite cell populations from dissociated skeletal muscle from mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:Utilizing glycerol intramuscular injections in M. musculus provide a models of skeletal muscle damage followed by skeletal muscle regeneration. In particular, glycerol-induced muscle injury triggers accute activation of skeletal muscle stem cells, called satellite cells. However, aging dramatically impairs the regenerative capacity of satellite cells. We characterized genome-wide expression profiles of young and old satellite cells in the non-proliferative and activated state, freshly isolated to non-injured or damaged muscles, respectively. Our goal was to uncover new regulatory signaling specific to satellite cells entry into the activation and myogenic program that are affected with age. Satellite cells were isolated in either quiescent / non-proliferative or activated state from uninjured or 3 days after glycerol-induced injury of tibialis anterior, gastrocnemius and quadriceps, respectively. Young (2-4 months old) and old (20-24 months old) wildtype C57BL/6J male were used, with five to six biological replicates per group.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:(Abstract of publication submitted currently) To clarify molecular regulation of satellite cells, we performed genome-wide gene expression analysis of quiescent satellite cells isolated from mouse skeletal muscle by flow cytometry. We identified 53 novel quiescent satellite cell-specific genes whose expressions are sharply down-regulated upon activation. The gene list contains a number of cell surface molecules, transcriptional factors, and cytokines and other signal transduction molecules. We further confirmed that Odz4 and calcitonin receptor proteins were expressed by quiescent but not by activated satellite cells in vivo. Importantly, we found that Pax7+/calcitonin receptor+ satellite cells reappear in close association with regenerating myofibers 7 days after muscle damage, often outside the basal lamina. Moreover, an agonist of calcitonin receptor suppressed the activation of quiescent satellite cells on myofibers in in vitro culture, suggesting that calcitonin receptor signaling plays an important role in renewal and maintenance of satellite cells. Our results show the gene expression profile of quiescent satellite cells for the first time and reveal the temporal and spatial reappearance of a satellite cell pool. Keywords: cell type comparison
Project description:The influence of the extracellular matrix (ECM) within the stem cell niche remains poorly understood. We found that Syndecan-4 (Sdc4) and Frizzled-7 (Fzd7) form a coreceptor complex in satellite cells and that binding of the ECM glycoprotein Fibronectin (FN) to Sdc4 stimulates the ability of Wnt7a to induce the symmetric expansion of satellite stem cells. Newly activated satellite cells dynamically remodel their niche via transient high-level expression of FN. Knockdown of FN in prospectively isolated satellite cells severely impaired their ability to repopulate the satellite cell niche. Conversely, in vivo overexpression of FN with Wnt7a dramatically stimulated the expansion of satellite stem cells in regenerating muscle. Therefore, activating satellite cells remodel their niche through autologous expression of FN that provides feedback to stimulate Wnt7a signaling through the Fzd7/Sdc4 coreceptor complex. Thus, FN and Wnt7a together regulate the homeostatic levels of satellite stem cells and satellite myogenic cells during regenerative myogenesis. The data set contains one microarray of pooled quiescent skeletal muscle satellite cells
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)