ABSTRACT: Skeletal muscle has great regenerative capacity, which is dependent on muscle stem cells, also known as satellite cells. We established the purification system of myogenic cells. We used microarrays to identify specific genes during the muscle regenerative process. Myogenic cells were purified at regenerative stages for RNA extraction and hybridization on Affymetrix microarrays. CTX-2d and CTX-5d are the samples derived from injured muscles 2 days and 5 days after cardiotoxin-injection, respectively.
Project description:Regeneration of skeletal muscle following injury is accompanied by transient inflammation initiation and resolution. However, it is unclear what signals control these processes. To better understand the biological pathways by C3a-C3aR activation in monocyte druing muscle regeneration,we examined global transcriptional changes in macrophages from the muscle after CTX injury.Male C57BL/6J mice were used at 12 weeks of age. 30 ul 10uM Cardiotoxin (CTX) was injected to TA muscle to injury muscle. CD11b+ cells was isolated from WT and C3aR-/- muscle at 1 day after CTX injury by FACS , then total RNA obtained from these cells were used for the analysis of RNA-seq.
Project description:The BM-derived CD45+/Sca1+ cells are haematopoietic stem/progenitor cells that have the ability to circulate and migrate and engraft to the muscle tissue, and therefore they are of particular interest. Notably, these cells retain their haematopoietic potential, as revealed both by in vitro and in vivo assays; but they also acquire myogenic potential, as shown by their ability to participate in muscle regeneration. Whether, this latter remarkable ability is the result of the reprogramming of the BM-CD45+/Sca1+ cells and the activation of a myogenic molecular program within these cells, remains controversial. This study aims to clarify this aspect of the process, investigating the role of the muscle microenviroment and key myogenic transcription factors. Keywords: CD45+/Sca1+ cells, BM, muscle CD45+/Sca1+ cells isolated from the BM or the muscle were processed fresh and their RNA was extracted. Moreover, CD45+/Sca1+ cells isolated from the muscle of BM transplanted or untransplanted mice after injury with Cardiotoxin were processed fresh and their RNA was extracted.
Project description:Utilizing glycerol and cardiotoxin (CTX) injections in the tibialis anterior muscles of M. musculus provides models of skeletal muscle damages followed by skeletal muscle regeneration. In particular, glycerol-induced muscle regeneration is known to be associated with ectopic adipogenesis. We characterized genome-wide expression profiles of tibialis anterior muscles from wild-type mice injured by either glycerol or CTX injection. Our goal was to detect gene expression changes during the time course of glycerol-induced and CTX-induced muscle regeneration models, that can lead to ectopic adipocyte accumulation. Tibialis anterior muscle of 12 week old wildtype C57BL/6J male mice injected i.m with either glycerol or CTX were collected 3, 7, 14 or 21 days after injection. 6 biological replicates were used for each time points. Please note that a few replicate samples did not pass QC test, thus, were removed from the submission. Unchallenged tibialis anterior muscles from a group of 5 wildtype C57BL/6J mice were also as a control. Total RNA was extracted, QCed and hybridized to Affymetrix microarrays.
Project description:We identified genes expressed in mouse skeletal muscle, during the process of muscle regeneration after injury, which are dysregulated in the absence of Mef2a expression. MEF2A is a member of the evolutionarily conserved MEF2 transcription factor family which has known roles in cardiac muscle development and function, but is not well studied in skeletal muscle. We performed a comparison of gene expression profiles in wild type and MEF2A knockout tibialis anterior muscle, seven days post-injury with cardiotoxin. The results indicated that a variety of genes expressed during muscle regeneration, predominantly microRNAs in the Gtl2-Dio3 locus, are dysregulated by the loss of MEF2A expression. Skeletal muscle RNA used in the present study included the following two sample groups: (WT) pooled total RNA from tibialis anterior muscle taken from 5 wild type mice at seven days post-injury with 10uM cardiotoxin; (KO) pooled total RNA from tibialis anterior muscle taken from 5 Mef2a knockout mice at seven days post-injury with 10uM cardiotoxin. All mice were between 2-4 months of age. Both male and female mice were used.
Project description:Muscle injury was elicited by cardiotoxin injection into the tibialis anterior muscle. Macrophages were isolated 2 days post-injury from the regenerating muscle. We used microarray to obtain global gene expression data of muscle-derived tissue macrophage subsets. Tissue macrophages were collected from regenerating muscle samples of three animals, Ly6C+ F4/80low and Ly6C- F4/80high macrophage subsets were sorted. The global gene expression patterns of distinct macrophage subsets were analyzed on Affymetrix microarrays.
Project description:Muscle injury was elicited by cardiotoxin injection into the tibialis anterior muscle. Macrophages were isolated 2 days post-injury from the regenerating muscle. We used microarray to obtain global gene expression data of muscle-derived tissue macrophage subsets. Tissue macrophages were collected from regenerating muscle samples of three animals, Ly6C+ F4/80low and Ly6C- F4/80high macrophage subsets were sorted. The global gene expression patterns of distinct macrophage subsets were analyzed on Affymetrix microarrays.
Project description:Tibialis anterior muscle was damaged by cardiotoxin injection and macrophage subsets were isolated and analyzed by gene expression analysis. We used microarray to obtain global gene expression data of muscle-derived tissue macrophage subsets. Tissue macrophages were collected from regenerating muscle samples, Gr1+/Cx3cr1low and Gr1-/Cx3cr1high macrophage subsets were sorted. The global gene expression patterns of distinct macrophage subsets were analyzed on Affymetrix microarrays.
Project description:We report age-related gene expression of Treg cells isolated from injured muscle and spleen. Male C57BL/6 Foxp3-GFP reporter mice were injured intramuscularly with cardiotoxin. Tregs were sorted directly into Trizol from injured muscle and spleen 4 days post-injury. Gene expression profiling of muscle and splenic Tregs from 2- vs >6-month old mice (biological duplicate for each).
Project description:MicroRNAs (miRNAs) are important in the regulation of many biological processes including muscle development. However, little is known regarding miRNA regulation of muscle regeneration. In mature murine tibialis anterior muscle following injury, 298 miRNAs were significantly changed during the time course of muscle regeneration including 86 that were altered greater than 10-fold as compared to uninjured muscle. Temporal miRNA expression patterns were identified and included inflammation-related miRNAs (miR-223 and -147) that increased immediately after injury; this pattern contrasted to that of mature muscle-specific miRNAs (miR-1, -133a and -499) that were abruptly decreased following injury and then up-regulated in later regenerative events. Another cluster of miRNAs were transiently increased in the early days of muscle regeneration. This included miR-351, a miRNA that was also transiently expressed during myogenic progenitor cell (MPC) differentiation in vitro. Based on computational predictions, further studies demonstrated that E2f3 was a target of miR-351 in myoblasts. Moreover, knockdown of miR-351 expression inhibited MPC proliferation and promoted apoptosis during MPC differentiation, whereas miR-351 overexpression protected MPC from apoptosis during differentiation. Collectively, these observations suggest that miR-351 is involved in both the maintenance of MPC proliferation and the transition of MPC into differentiated myotubes. Thus, a novel, time-dependent sequence of molecular events during skeletal muscle regeneration has been identified, i.e., miR-351 inhibits E2f3 expression, a key regulator of cell cycle progression and proliferation, and promotes MPC proliferation and protects early differentiating MPC from apoptosis, important events in the hostile tissue environment after acute muscle injury. Skeletal muscles are damaged and repaired repeatedly throughout life. Muscle regeneration maintains locomotor function during aging and delays the appearance of clinical symptoms in neuromuscular diseases, such as Duchenne muscular dystrophy. The capacity for skeletal muscle growth and regeneration is conferred by satellite cells located between the basal lamina and the sarcolemma of mature myofibers. Upon injury, satellite cells reenter the cell cycle, proliferate, and then exit the cell cycle either to renew the quiescent satellite cell pool or to differentiate into mature myofibers. Despite recent advances, genes involved in these processes are still largely unknown. Understanding the molecular mechanisms that regulate satellite cell activities could promote development of novel countermeasures to enhance muscle regeneration that is compromised by diseases or aging. Using a muscle injury mouse model, we profiled miRNA expression during muscle regeneration.
Project description:In order to understand the role of miRNAs in muscle regeneration we injected cardiotoxin into the tibialis muscle of mice and isolated using FACS two different groups of adult muscle stem cells. RNA was isolated directly from sorted cells and analyzed by miRNA deep sequencing.