Project description:To confirm changing C2C12 cells genetic profile and losing their myogenic ability, we investigated the combined effect of EPA and DHA on the relative expression of genes regulating the terminal differentiation of myoblast into mature multinucleated myotubes.
Project description:Wnt/M-NM-2-catenin signaling is involved in various aspects of skeletal muscle development and regeneration. In addition, Wnt3a and M-NM-2-catenin are required for muscle-specific gene transcription in embryonic carcinoma cells and satellite-cell proliferation during adult skeletal muscle regeneration. Downstream targets of canonical Wnt signaling are cyclin D1 and c-myc. However, both target genes are suppressed during differentiation of mouse myoblast cells, C2C12. Underlying molecular mechanisms of M-NM-2-catenin signaling during myogenic differentiation remain unknown. Using C2C12 cells, we examined intracellular signaling and gene transcription during myoblast proliferation and differentiation. We confirmed that several Wnt signaling components, including Wnt9a, Sfrp2 and porcupine, were consistently upregulated in differentiating C2C12 cells. Troponin T-positive myotubes were decreased by Wnt3a overexpression, but not Wnt4. TOP/FOP reporter assays revealed that co-expression with Wnt4 reduced Wnt3a-induced luciferase activity, suggesting that Wnt4 signaling counteracted Wnt3a signaling in myoblasts. FH535, a small-molecule inhibitor of M-NM-2-catenin/Tcf complex formation, reduced basal M-NM-2-catenin in cytoplasm and decreased myoblast proliferation. K252a, a protein kinase inhibitor, increased membrane-bound M-NM-2-catenin and enhanced myoblast fusion. Treatments with K252a or Wnt4 resulted in increased cytoplasmic vesicles containing phosphorylated M-NM-2-catenin (Tyr654) during myogenic differentiation. These results suggest that various Wnt ligands control subcellular M-NM-2-catenin localization, which regulate myoblast proliferation and myotube formation. Wnt signaling via M-NM-2-catenin likely acts as a molecular switch that regulates the transition from cell proliferation to myogenic differentiation. Control cells (day 0) prior to differentiation induction with n=4; differentiated for two days with n=3; differentiated for four days with n=3.
Project description:Wnt/β-catenin signaling is involved in various aspects of skeletal muscle development and regeneration. In addition, Wnt3a and β-catenin are required for muscle-specific gene transcription in embryonic carcinoma cells and satellite-cell proliferation during adult skeletal muscle regeneration. Downstream targets of canonical Wnt signaling are cyclin D1 and c-myc. However, both target genes are suppressed during differentiation of mouse myoblast cells, C2C12. Underlying molecular mechanisms of β-catenin signaling during myogenic differentiation remain unknown. Using C2C12 cells, we examined intracellular signaling and gene transcription during myoblast proliferation and differentiation. We confirmed that several Wnt signaling components, including Wnt9a, Sfrp2 and porcupine, were consistently upregulated in differentiating C2C12 cells. Troponin T-positive myotubes were decreased by Wnt3a overexpression, but not Wnt4. TOP/FOP reporter assays revealed that co-expression with Wnt4 reduced Wnt3a-induced luciferase activity, suggesting that Wnt4 signaling counteracted Wnt3a signaling in myoblasts. FH535, a small-molecule inhibitor of β-catenin/Tcf complex formation, reduced basal β-catenin in cytoplasm and decreased myoblast proliferation. K252a, a protein kinase inhibitor, increased membrane-bound β-catenin and enhanced myoblast fusion. Treatments with K252a or Wnt4 resulted in increased cytoplasmic vesicles containing phosphorylated β-catenin (Tyr654) during myogenic differentiation. These results suggest that various Wnt ligands control subcellular β-catenin localization, which regulate myoblast proliferation and myotube formation. Wnt signaling via β-catenin likely acts as a molecular switch that regulates the transition from cell proliferation to myogenic differentiation.
Project description:We newly identified skeletal muscle differentiation-associated miRNAs by comparing miRNA expression profile between C2C12 cell and Wnt4-overexpressing C2C12 cell. miR-487b, miR-3963 and miR-6412 are significantly down-regulated in differentiating C2C12 cells, and transfection of their mimics resulted in reduced expression of myogenic differentiation markers including Troponin T, myosin heavy chain fast and slow type. Single analysis for each condition (proliferating C2C12 cells, differentiating C2C12 cells, proliferating Wnt4-overexpressing C2C12 subline cells
Project description:We newly identified skeletal muscle differentiation-associated miRNAs by comparing miRNA expression profile between C2C12 cell and Wnt4-overexpressing C2C12 cell. miR-487b, miR-3963 and miR-6412 are significantly down-regulated in differentiating C2C12 cells, and transfection of their mimics resulted in reduced expression of myogenic differentiation markers including Troponin T, myosin heavy chain fast and slow type.
Project description:To study the gene expression profile difference caused by miR-322/-503 overexpression in the myoblast differentiation of DM1 group, we performed RNA-seq on the total RNA samples collected from the in vitro myoblast differentiation day 4 of control and miR-322/-503 overexpressing DM1 C2C12 cell models. The DM1 cell model was bulit by stably transfecting C2C12 cells with GFP-CUG200 plasmid. Each group contained three biological replicates. The expression matrix was obtained by Hisat2 followed by Stringtie.
Project description:Skeletal muscle contains long multinucleated and contractile structures known as muscle fibers, which arise from the fusion of myoblasts into nucleated myotubes during myogenesis. The myogenic regulatory factor (MRF) MYF5 is the earliest to be expressed during myogenesis and functions as a transcription factor in muscle progenitor cells (satellite cells) and myocytes. In mouse C2C12 myocytes, MYF5 is implicated in the initial steps of myoblast differentiation into myotubes. Ribonucleoprotein immunoprecipitation (RIP) analysis showed that MYF5 bound a subset of myoblast mRNAs; prominent among them was Ccnd1 mRNA, which encodes the key cell cycle regulator CCND1 (Cyclin D1). Biotin-RNA pulldown, UV-crosslinking, and gel shift experiments indicated that MYF5 was capable of binding the 3' untranslated region (UTR) and the coding region (CR) of Ccnd1 mRNA. MYF5 silencing in proliferating growing myoblasts revealed that and MYF5 promoted CCND1 translation, and it also modestly increased transcription of Ccnd1 mRNA. Importantly, silencing MYF5 reduced myoblast growth as well as differentiation of myoblasts into myotubes, while overexpressing MYF5 in C2C12 cells upregulated CCND1 expression. We propose that MYF5 enhances early myogenesis in part by coordinately elevating Ccnd1 transcription and Ccnd1 mRNA translation. Four replicates were utilized from either Control (IgG) or MYF5-immunoprecipitated RNA samples from C2C12 cells growing in either growth medium (GM) or differentiation medium (DM) for a total of sixteen samples.
Project description:Skeletal muscle research is transitioning towards 3D tissue engineered in vitro models reproducing muscle’s native architecture and supporting measurement of functionality. Human induced pluripotent stem cells (hiPSCs) offer high yields of cells for differentiation. It has been difficult to differentiate high quality, pure 3D muscle tissues from hiPSCs that show contractile properties comparable to primary myoblast-derived tissues. Here, we present a transgene-free method for the generation of purified, expandable myogenic progenitors (MPs) from hiPSCs grown under feeder-free conditions. We defined a protocol with optimal hydrogel and medium conditions that allowed production of highly contractile 3D tissue engineered skeletal muscles with forces similar to primary myoblast-derived tissues. Gene expression and proteomic analysis between hiPSC-derived and primary myoblast-derived 3D tissues revealed a similar expression profile of proteins involved in myogenic differentiation and sarcomere function. The protocol should be generally applicable for the study of personalized human skeletal muscle tissue in health and disease.