A Novel Muscle-Specific β1 Integrin Binding Protein (Mibp) That Modulates Myogenic Differentiation

Myogenesis is regulated by cell adhesion receptors, including integrins of the β1 family. We report the identification of a novel muscle-specific β1 integrin binding protein (MIBP). MIBP binds to the membrane-proximal cytoplasmic region shared by β1A and β1D integrins, and the binding occurs in vivo as well as in vitro. Furthermore, we show that MIBP is abundantly expressed by C2C12 myogenic cells before fusion, and the expression of MIBP is dramatically downregulated during subsequent differentiation. Finally, we show that overexpression of MIBP in C2C12 cells resulted in a suppression of fusion and terminal differentiation, suggesting that MIBP may play a key role in controlling the progression of muscle differentiation.

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p27Kip1 Acts Downstream of N-Cadherin-mediated Cell Adhesion to Promote Myogenesis beyond Cell Cycle Regulation

Molecular Biology of the Cell ◽

10.1091/mbc.e04-07-0612 ◽

2005 ◽

Vol 16 (3) ◽

pp. 1469-1480 ◽

Cited By ~ 37

Author(s):

Graziella Messina ◽

Cristiana Blasi ◽

Severina Anna La Rocca ◽

Monica Pompili ◽

Attilio Calconi ◽

...

Keyword(s):

Cell Cycle ◽

Myogenic Differentiation ◽

Cell Cycle Control ◽

C2c12 Cell ◽

Terminal Differentiation ◽

Active Role ◽

C2c12 Cells ◽

Low Density

It is widely acknowledged that cultured myoblasts can not differentiate at very low density. Here we analyzed the mechanism through which cell density influences myogenic differentiation in vitro. By comparing the behavior of C2C12 myoblasts at opposite cell densities, we found that, when cells are sparse, failure to undergo terminal differentiation is independent from cell cycle control and reflects the lack of p27Kip1 and MyoD in proliferating myoblasts. We show that inhibition of p27Kip1 expression impairs C2C12 cell differentiation at high density, while exogenous p27Kip1 allows low-density cultured C2C12 cells to enter the differentiative program by regulating MyoD levels in undifferentiated myoblasts. We also demonstrate that the early induction of p27Kip1 is a critical step of the N-cadherin-dependent signaling involved in myogenesis. Overall, our data support an active role of p27Kip1 in the decision of myoblasts to commit to terminal differentiation, distinct from the regulation of cell proliferation, and identify a pathway that, reasonably, operates in vivo during myogenesis and might be part of the phenomenon known as “community effect”.

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6-Bromoindirubin-3′-oxime intercepts GSK3 signaling to promote and enhance skeletal muscle differentiation affecting miR-206 expression in mice

Scientific Reports ◽

10.1038/s41598-019-54574-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Elvira Ragozzino ◽

Mariarita Brancaccio ◽

Antonella Di Costanzo ◽

Francesco Scalabrì ◽

Gennaro Andolfi ◽

...

Keyword(s):

Skeletal Muscle ◽

Myogenic Differentiation ◽

Muscle Differentiation ◽

C2c12 Cells ◽

Skeletal Muscle Differentiation ◽

Myoblast Proliferation ◽

Enhanced Expression ◽

Pharmacologically Active

AbstractDystrophies are characterized by progressive skeletal muscle degeneration and weakness as consequence of their molecular abnormalities. Thus, new drugs for restoring skeletal muscle deterioration are critically needed. To identify new and alternative compounds with a functional role in skeletal muscle myogenesis, we screened a library of pharmacologically active compounds and selected the small molecule 6-bromoindirubin-3′-oxime (BIO) as an inhibitor of myoblast proliferation. Using C2C12 cells, we examined BIO’s effect during myoblast proliferation and differentiation showing that BIO treatment promotes transition from cell proliferation to myogenic differentiation through the arrest of cell cycle. Here, we show that BIO is able to promote myogenic differentiation in damaged myotubes in-vitro by enriching the population of newly formed skeletal muscle myotubes. Moreover, in-vivo experiments in CTX-damaged TA muscle confirmed the pro-differentiation capability of BIO as shown by the increasing of the percentage of myofibers with centralized nuclei as well as by the increasing of myofibers number. Additionally, we have identified a strong correlation of miR-206 with BIO treatment both in-vitro and in-vivo: the enhanced expression of miR-206 was observed in-vitro in BIO-treated proliferating myoblasts, miR-206 restored expression was observed in a forced miR-206 silencing conditions antagomiR-mediated upon BIO treatment, and in-vivo in CTX-injured muscles miR-206 enhanced expression was observed upon BIO treatment. Taken together, our results highlight the capacity of BIO to act as a positive modulator of skeletal muscle differentiation in-vitro and in-vivo opening up a new perspective for novel therapeutic targets to correct skeletal muscle defects.

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Myogenic regulatory factors regulate M-cadherin expression by targeting its proximal promoter elements

Biochemical Journal ◽

10.1042/bj20100250 ◽

2010 ◽

Vol 428 (2) ◽

pp. 223-233 ◽

Cited By ~ 17

Author(s):

Sheng Pin Hsiao ◽

Shen Liang Chen

Keyword(s):

Cell Adhesion ◽

Transcription Initiation ◽

Myogenic Differentiation ◽

Initiation Site ◽

Proximal Promoter ◽

Myogenic Regulatory Factors ◽

Regulatory Factors ◽

Cell Cell

M- and N-cadherin are members of the Ca2+-dependent cell–cell adhesion molecule family. M-cadherin is expressed predominantly in developing skeletal muscles and has been implicated in terminal myogenic differentiation, particularly in myoblast fusion. N-cadherin-mediated cell–cell adhesion also plays an important role in skeletal myogenesis. In the present study, we found that both genes were differentially expressed in C2C12 and Sol8 myoblasts during myogenic differentiation and that the expression of M-cadherin was preferentially enhanced in slow-twitch muscle. Interestingly, most MRFs (myogenic regulatory factors) significantly activated the promoter of M-cadherin, but not that of N-cadherin. In line with this, overexpression of MyoD in C3H10T1/2 fibroblasts strongly induced endogenous M-cadherin expression. Promoter analysis in silico and in vitro identified an E-box (from −2 to +4) abutting the transcription initiation site within the M-cadherin promoter that is bound and differentially activated by different MRFs. The activation of the M-cadherin promoter by MRFs was also modulated by Bhlhe40 (basic helix–loop–helix family member e40). Finally, chromatin immunoprecipitation proved that MyoD as well as myogenin binds to the M-cadherin promoter in vivo. Taken together, these observations identify a molecular mechanism by which MRFs regulate M-cadherin expression directly to ensure the terminal differentiation of myoblasts.

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Hes6 regulates myogenic differentiation

Development ◽

10.1242/dev.129.9.2195 ◽

2002 ◽

Vol 129 (9) ◽

pp. 2195-2207

Author(s):

Judy Cossins ◽

Ann E. Vernon ◽

Yun Zhang ◽

Anna Philpott ◽

Philip H. Jones

Keyword(s):

Protein Interactions ◽

Kinase Inhibitor ◽

Myogenic Differentiation ◽

C2c12 Cells ◽

Myoblast Differentiation ◽

C2c12 Myoblast ◽

Xenopus Embryos ◽

Enhancer Of Split

Hes6 is a basic helix-loop-helix transcription factor homologous to Drosophila Enhancer of Split (EoS) proteins. It is known to promote neural differentiation and to bind to Hes1, a related protein that is part of the Notch signalling pathway, affecting Hes1-regulated transcription. We show that Hes6 is expressed in the murine embryonic myotome and is induced on C2C12 myoblast differentiation in vitro. Hes6 binds DNA containing the Enhancer of Split E box (ESE) motif, the preferred binding site of Drosophila EoS proteins, and represses transcription of an ESE box reporter. When overexpressed in C2C12 cells, Hes6 impairs normal differentiation, causing a decrease in the induction of the cyclin-dependent kinase inhibitor, p21Cip1, and an increase in the number of cells that can be recruited back into the cell cycle after differentiation in culture. In Xenopus embryos, Hes6 is co-expressed with MyoD in early myogenic development. Microinjection of Hes6 RNA in vivo in Xenopus embryos results in an expansion of the myotome, but suppression of terminal muscle differentiation and disruption of somite formation at the tailbud stage. Analysis of Hes6 mutants indicates that the DNA-binding activity of Hes6 is not essential for its myogenic phenotype, but that protein-protein interactions are. Thus, we demonstrate a novel role for Hes6 in multiple stages of muscle formation.

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Abstract 17273: Long Non-Coding RNA Ppp1r1b Regulates Myogenic Differentiation Through Modulating Histone 3 Methylation

Circulation ◽

10.1161/circ.138.suppl_1.17273 ◽

2018 ◽

Vol 138 (Suppl_1) ◽

Author(s):

Xuedong Kang ◽

Yan Zhao ◽

Marlin Touma

Keyword(s):

Histone Modification ◽

Protein Complex ◽

Myogenic Differentiation ◽

C2c12 Cells ◽

Myoblast Differentiation ◽

Mouse Heart ◽

Histone 3

Introduction: Long noncoding RNAs (lncRNAs), emerged as critical epigenetic regulators of transcriptome, play important roles in cardiac development and might be targeted to treat human cardiomyocyte dysfunction. In our work, we identified a novel lncRNA that regulates myogenesis. Hypothesis: LncRNA Ppp1r1b regulates myogenesis by modulating Histone 3 methylation Methods: After treated with antisense oligonucleotides (GapmeR) or siRNA against Ppp1r1b-LncRNA, real time PCR and Western blot analyses were performed to examine the expression of myogenic and sarcomere genes. Chromatin immunoprecipitation (CHIP) was used to comparatively analyze gene specific histone modification level. RNA pull-down was employed to identify the protein molecules that interact with Ppp1r1b-LncRNA. Results: By silencing Ppp1r1b-LncRNA with GapmeR, C2C12, a skeletal myoblast cell line, did not develop fully differentiated myotubes, but tend to remain in a quiescent mono-nucleated status. In vivo analysis of GapmeR injected neonatal mouse heart and in vitro siRNA silenced human skeletal myoblasts further confirmed the important role of Ppp1r1b-LncRNA on myogenesis. Members of the MyoD family of muscle-specific transcription factors (MyoD and myogenin) failed to be up-regulated during myogenic differentiation when treated with Ppp1r1b-LncRNA specific GapmeR or siRNA. Key proteins essential for establishing and maintaining normal skeletal muscle architecture, including Tcap and Dystropnin, are also suppressed in Ppp1r1b LncRNA- deficient heart. Analysis of histone modification levels at Myogenin, MyoD1 and Tcap in C2C12 cells revealed more histone tri-methylation at these myogenic and sarcomere structural genes compared to untreated cells. Additional lncRNA- protein complex isolation has further revealed insight into the biological roles of Ppp1r1b-LncRNA. Conclusions: Our results support the role of Ppp1r1b-LncRNA in promoting myogenic differentiation. Ppp1r1b-lncRNA function is mediated by inhibiting histone methylation on promoters of multiple myogenic and sarcomere genes. In particular, the identification of EZH2 in pulled Pp1r1b LncRNA: protein complex implies that Polycomb repressive complex 2 (PRC2) is involved in Ppp1r1b-LncRNA modulated myoblast differentiation.

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Metalloprotease-disintegrin ADAM 12 interacts with α-actinin-1

Biochemical Journal ◽

10.1042/bj3570353 ◽

2001 ◽

Vol 357 (2) ◽

pp. 353-361 ◽

Cited By ~ 12

Author(s):

Yi CAO ◽

Qing KANG ◽

Anna ZOLKIEWSKA

Keyword(s):

Cell Adhesion ◽

Fluorescent Protein ◽

Critical Role ◽

Cytoplasmic Domain ◽

C2c12 Cells ◽

Actin Binding ◽

Myoblast Differentiation ◽

Adam 12

ADAM 12, a member of the ADAM family of proteins (containing ADisintegrin And Metalloprotease domain), has been implicated in differentiation and fusion of myoblasts. While the extracellular domain of ADAM 12 contains an active metalloprotease and a region involved in cell adhesion, the function of the cytoplasmic tail of ADAM 12 has been less clear. Here we show that the cytoplasmic domain of ADAM 12 interacts in vitro and in vivo with α-actinin-1, an actin-binding and cross-linking protein. Green fluorescent protein fused to ADAM 12 cytoplasmic domain co-localizes with α-actinin-1-containing actin stress fibres in C2C12 cells. The interaction between ADAM 12 and α-actinin-1 is direct and involves the 58-amino acid C-terminal fragment of ADAM 12 and the 27kDa N-terminal domain of α-actinin-1. Consistently, expression of the 27kDa fragment of α-actinin-1 in C2C12 cells using a mitochondrial targeting system results in recruitment of the co-expressed ADAM 12 cytoplasmic domain to the mitochondrial surface. Moreover, α-actinin-1 co-purifies with a transmembrane, His6-tagged form of ADAM 12 expressed in C2C12 myoblasts, indicating that the transmembrane ADAM 12 forms a complex with α-actinin-1 in vivo. These results indicate that the actin cytoskeleton may play a critical role in ADAM 12-mediated cell–cell adhesion or cell signalling during myoblast differentiation and fusion.

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Loss of splicing factor IK impairs normal skeletal muscle development

BMC Biology ◽

10.1186/s12915-021-00980-y ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Hye In Ka ◽

Hyemin Seo ◽

Youngsook Choi ◽

Joohee Kim ◽

Mina Cho ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Development ◽

Myogenic Differentiation ◽

Mrna Splicing ◽

C2c12 Cells ◽

Splicing Factor ◽

Skeletal Muscle Development

Abstract Background IK is a splicing factor that promotes spliceosome activation and contributes to pre-mRNA splicing. Although the molecular mechanism of IK has been previously reported in vitro, the physiological role of IK has not been fully understood in any animal model. Here, we generate an ik knock-out (KO) zebrafish using the CRISPR/Cas9 system to investigate the physiological roles of IK in vivo. Results The ik KO embryos display severe pleiotropic phenotypes, implying an essential role of IK in embryonic development in vertebrates. RNA-seq analysis reveals downregulation of genes involved in skeletal muscle differentiation in ik KO embryos, and there exist genes having improper pre-mRNA splicing among downregulated genes. The ik KO embryos display impaired neuromuscular junction (NMJ) and fast-twitch muscle development. Depletion of ik reduces myod1 expression and upregulates pax7a, preventing normal fast muscle development in a non-cell-autonomous manner. Moreover, when differentiation is induced in IK-depleted C2C12 myoblasts, myoblasts show a reduced ability to form myotubes. However, inhibition of IK does not influence either muscle cell proliferation or apoptosis in zebrafish and C2C12 cells. Conclusion This study provides that the splicing factor IK contributes to normal skeletal muscle development in vivo and myogenic differentiation in vitro.

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Mechanism of CK2.3, a Novel Mimetic Peptide of Bone Morphogenetic Protein Receptor Type IA, Mediated Osteogenesis

International Journal of Molecular Sciences ◽

10.3390/ijms20102500 ◽

2019 ◽

Vol 20 (10) ◽

pp. 2500 ◽

Cited By ~ 3

Author(s):

Vrathasha Vrathasha ◽

Hilary Weidner ◽

Anja Nohe

Keyword(s):

Signaling Pathways ◽

Treatment Options ◽

Time Frame ◽

Bmp Signaling ◽

C2c12 Cells ◽

Molecular Sequence ◽

Sequence Of Events ◽

Protein Receptor

Background: Osteoporosis is a degenerative skeletal disease with a limited number of treatment options. CK2.3, a novel peptide, may be a potential therapeutic. It induces osteogenesis and bone formation in vitro and in vivo by acting downstream of BMPRIA through releasing CK2 from the receptor. However, the detailed signaling pathways, the time frame of signaling, and genes activated remain largely unknown. Methods: Using a newly developed fluorescent CK2.3 analog, specific inhibitors for the BMP signaling pathways, Western blot, and RT-qPCR, we determined the mechanism of CK2.3 in C2C12 cells. We then confirmed the results in primary BMSCs. Results: Using these methods, we showed that CK2.3 stimulation activated OSX, ALP, and OCN. CK2.3 stimulation induced time dependent release of CK2β from BMPRIA and concurrently CK2.3 colocalized with CK2α. Furthermore, CK2.3 induced BMP signaling depends on ERK1/2 and Smad1/5/8 signaling pathways. Conclusion: CK2.3 is a novel peptide that drives osteogenesis, and we detailed the molecular sequence of events that are triggered from the stimulation of CK2.3 until the induction of mineralization. This knowledge can be applied in the development of future therapeutics for osteoporosis.

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C4b-binding protein α-chain enhances antitumor immunity by facilitating the accumulation of tumor-infiltrating lymphocytes in the tumor microenvironment in pancreatic cancer

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-02019-0 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Kosuke Sasaki ◽

Shigetsugu Takano ◽

Satoshi Tomizawa ◽

Yoji Miyahara ◽

Katsunori Furukawa ◽

...

Keyword(s):

T Cell ◽

Tumor Microenvironment ◽

Binding Protein ◽

Combined Treatment ◽

Tumor Infiltrating Lymphocytes ◽

Pdac Cell ◽

Α Chain ◽

Infiltrating Lymphocytes

Abstract Background Recent studies indicate that complement plays pivotal roles in promoting or suppressing cancer progression. We have previously identified C4b-binding protein α-chain (C4BPA) as a serum biomarker for the early detection of pancreatic ductal adenocarcinoma (PDAC). However, its mechanism of action remains unclear. Here, we elucidated the functional roles of C4BPA in PDAC cells and the tumor microenvironment. Methods We assessed stromal C4BPA, the C4BPA binding partner CD40, and the number of CD8+ tumor-infiltrating lymphocytes in resected human PDAC tissues via immunohistochemical staining. The biological functions of C4BPA were investigated in peripheral blood mononuclear cells (PBMCs) and human PDAC cell lines. Mouse C4BPA (mC4BPA) peptide, which is composed of 30 amino acids from the C-terminus and binds to CD40, was designed for further in vitro and in vivo experiments. In a preclinical experiment, we assessed the efficacy of gemcitabine plus nab-paclitaxel (GnP), dual immune checkpoint blockades (ICBs), and mC4BPA peptide in a mouse orthotopic transplantation model. Results Immunohistochemical analysis revealed that high stromal C4BPA and CD40 was associated with favorable PDAC prognosis (P=0.0005). Stromal C4BPA strongly correlated with the number of CD8+ tumor-infiltrating lymphocytes (P=0.001). In in vitro experiments, flow cytometry revealed that recombinant human C4BPA (rhC4BPA) stimulation increased CD4+ and CD8+ T cell numbers in PBMCs. rhC4BPA also promoted the proliferation of CD40-expressing PDAC cells. By contrast, combined treatment with gemcitabine and rhC4BPA increased PDAC cell apoptosis rate. mC4BPA peptide increased the number of murine T lymphocytes in vitro and the number of CD8+ tumor-infiltrating lymphocytes surrounding PDAC tumors in vivo. In a preclinical study, GnP/ICBs/mC4BPA peptide treatment, but not GnP treatment, led to the accumulation of a greater number of CD8+ T cells in the periphery of PDAC tumors and to greater tumor regression than did control treatment. Conclusions These findings demonstrate that the combination of GnP therapy with C4BPA inhibits PDAC progression by promoting antitumor T cell accumulation in the tumor microenvironment.

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