scholarly journals Critical Role Played by Cyclin D3 in the MyoD-Mediated Arrest of Cell Cycle during Myoblast Differentiation

1999 ◽  
Vol 19 (7) ◽  
pp. 5203-5217 ◽  
Author(s):  
Carlo Cenciarelli ◽  
Francesca De Santa ◽  
Pier Lorenzo Puri ◽  
Elisabetta Mattei ◽  
Letizia Ricci ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Critical Role ◽  
Cyclin D3 ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Gene Expressions ◽  
Adenovirus E1a ◽  
Skeletal Myoblasts ◽  
Myogenic Factors ◽  
Cell Cycle Inhibitors

ABSTRACT During the terminal differentiation of skeletal myoblasts, the activities of myogenic factors regulate not only tissue-specific gene expressions but also the exit from the cell cycle. The induction of cell cycle inhibitors such as p21 and pRb has been shown to play a prominent role in the growth arrest of differentiating myoblasts. Here we report that, at the onset of differentiation, activation by MyoD of the Rb, p21, and cyclin D3 genes occurs in the absence of new protein synthesis and with the requirement of the p300 transcriptional coactivator. In differentiated myocytes, cyclin D3 also becomes stabilized and is found nearly totally complexed with unphosphorylated pRb. The detection of complexes containing cyclin D3, cdk4, p21, and PCNA suggests that cdk4, along with PCNA, may get sequestered into high-order structures held together by pRb and cyclin D3. Cyclin D3 up-regulation and stabilization is inhibited by adenovirus E1A, and this correlates with the ability of E1A to promote pRb phosphorylation; conversely, the overexpression of cyclin D3 in differentiated myotubes counteracts the E1A-mediated reactivation of DNA synthesis. These results indicate that cyclin D3 critically contributes to the irreversible exit of differentiating myoblasts from the cell cycle.

Abstract P070: NEU3 Sialidase Overexpression Activates Cell Survival in Murine Skeletal Myoblasts C2C12 and Protects Them from Hypoxia

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Luigi Anastasia ◽  
Raffaella Scaringi ◽  
Nadia Papini ◽  
Andrea Garatti ◽  
Lorenzo Menicanti ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Egf Receptor ◽  
Day Treatment ◽  
Horse Serum ◽  
Critical Role ◽  
Cell Loss ◽  
Myoblast Differentiation ◽  
Signalling Pathways ◽  
Skeletal Myoblasts ◽  
Culturing Conditions

Membrane-bound sialidase NEU3 increase during skeletal muscle differentiation has been shown to protect myoblasts from apoptosis and drive the differentiation process [1]. Thus, the objective of this study was to assess whether up-regulation of NEU3 would enhance the ability of murine skeletal muscle cells to resist to hypoxia, ultimately opposing cell death. We found that C2C12 myoblasts overexpressing NEU3 (L-NEU3) became highly resistant to 1% oxygen or 200 mM deferoxamine induced hypoxia. Moreover, L-NEU3 myoblasts survived a seven-day treatment of combined hypoxia and low serum (2% horse serum used to induce myoblast differentiation), without any significant cell loss. On the contrary, wild type C2C12 could not resist to these culturing conditions and all died within 48h. Real Time PCR showed NEU3 expression increase during all hypoxic treatments both in C2C12 and L-NEU3 cells, suggesting an endogenous NEU3 activation under these conditions. Moreover, we found that NEU3 over-expression activated pro-survival signalling pathways through up-regulation and activation of EGF receptor. Overall, our data support the hypothesis that NEU3 may play a critical role in the response of skeletal myoblasts to hypoxia and the preservation of cell viability by activating pro-survival signalling pathways. [1] Anastasia L. et al. J.Biol.Chem. 2008, 283 (52): 36265–36271.

scholarly journals pRb-Dependent Cyclin D3 Protein Stabilization Is Required for Myogenic Differentiation

2007 ◽  
Vol 27 (20) ◽  
pp. 7248-7265 ◽  
Author(s):  
Francesca De Santa ◽  
Sonia Albini ◽  
Eleonora Mezzaroma ◽  
Livio Baron ◽  
Armando Felsani ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Myogenic Differentiation ◽  
Ectopic Expression ◽  
Protein Stabilization ◽  
Cyclin D3 ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Protein Accumulation ◽  
C Terminus ◽  
Gsk 3Β

ABSTRACT The expression of retinoblastoma (pRb) and cyclin D3 proteins is highly induced during the process of skeletal myoblast differentiation. We have previously shown that cyclin D3 is nearly totally associated with hypophosphorylated pRb in differentiated myotubes, whereas Rb − / − myocytes fail to accumulate the cyclin D3 protein despite normal induction of cyclin D3 mRNA. Here we report that pRb promotes cyclin D3 protein accumulation in differentiating myoblasts by preventing cyclin D3 degradation. We show that cyclin D3 displays rapid turnover in proliferating myoblasts, which is positively regulated through glycogen synthase kinase 3β (GSK-3β)-mediated phosphorylation of cyclin D3 on Thr-283. We describe a novel interaction between pRb and cyclin D3 that maps to the C terminus of pRb and to a region of cyclin D3 proximal to the Thr-283 residue and provide evidence that the pRb-cyclin D3 complex formation in terminally differentiated myotubes hinders the access of GSK-3β to cyclin D3, thus inhibiting Thr-283 phosphorylation. Interestingly, we observed that the ectopic expression of a stabilized cyclin D3 mutant in C2 myoblasts enhances muscle-specific gene expression; conversely, cyclin D3-null embryonic fibroblasts display impaired MyoD-induced myogenic differentiation. These results indicate that the pRb-dependent accumulation of cyclin D3 is functionally relevant to the process of skeletal muscle cell differentiation.

scholarly journals Sequestration of pRb by Cyclin D3 Causes Intranuclear Reorganization of Lamin A/C during Muscle Cell Differentiation

2005 ◽  
Vol 16 (4) ◽  
pp. 1948-1960 ◽  
Author(s):  
Indumathi Mariappan ◽  
Veena K. Parnaik
Keyword(s):  
Muscle Cells ◽  
Cell Types ◽  
Cyclin D3 ◽  
Myoblast Differentiation ◽  
Regulatory Factor ◽  
C2c12 Myoblasts ◽  
Muscle Cell Differentiation ◽  
Adenovirus E1a ◽  
Nuclear Domains ◽  
Myogenic Program

The A-type lamins that localize in nuclear domains termed lamin speckles are reorganized and antigenically masked specifically during myoblast differentiation. This rearrangement was observed to be linked to the myogenic program as lamin speckles, stained with monoclonal antibody (mAb) LA-2H10, were reorganized in MyoD-transfected fibroblasts induced to transdifferentiate to muscle cells. In C2C12 myoblasts, speckles were reorganized early during differentiation in cyclin D3–expressing cells. Ectopic cyclin D3 induced lamin reorganization in C2C12 myoblasts but not in other cell types. Experiments with adenovirus E1A protein that can bind to and segregate the retinoblastoma protein (pRb) indicated that pRb was essential for the cyclin D3–mediated reorganization of lamin speckles. Cyclin D3–expressing myoblasts displayed site-specific reduction of pRb phosphorylation. Furthermore, disruption of lamin structures by overexpression of lamins inhibited expression of the muscle regulatory factor myogenin. Our results suggest that the reorganization of internal lamins in muscle cells is mediated by key regulators of the muscle differentiation program.

scholarly journals Expression of E1A in terminally differentiated muscle cells reactivates the cell cycle and suppresses tissue-specific genes by separable mechanisms.

1996 ◽  
Vol 16 (10) ◽  
pp. 5302-5312 ◽  
Author(s):  
M Tiainen ◽  
D Spitkovsky ◽  
P Jansen-Dürr ◽  
A Sacchi ◽  
M Crescenzi
Keyword(s):  
Cell Cycle ◽  
Kinase Inhibitor ◽  
Cyclin E ◽  
Muscle Cells ◽  
S Phase ◽  
Specific Gene ◽  
Muscle Creatine Kinase ◽  
Tissue Specific ◽  
Adenovirus E1a ◽  
Differentiated Cells

Terminally differentiated cells are characterized by permanent withdrawal from the cell cycle; they do not enter S phase even when stimulated by growth factors or retroviral oncogenes. We have shown, however, that the adenovirus E1A oncogene can reactivate the cell cycle in terminally differentiated cells. In this report, we describe the molecular events triggered by E1A in terminally differentiated skeletal muscle cells. We found that in myotubes infected with the adenovirus mutant dl520, 12S E1A bypasses the early G1 phase and activates the expression of late-G1 genes, such as the cyclin E and cyclin A genes, cdk2, PCNA, and B-myb. Of these, the cyclin E gene and cdk2 were significantly overexpressed in comparison with levels in proliferating, undifferentiated myoblasts. p130 and pRb were phosphorylated before the infected myotubes entered S phase, despite the high expression of the cyclin-dependent kinase inhibitor p21, and E2F was released. Our results suggest that one of the mechanisms that E1A uses to overcome the proliferative block of terminally differentiated cells involves coordinated overexpression of cyclin E and cdk2. Following E1A expression, the myogenic transcription factors MyoD and myogenin and the muscle-specific structural genes encoding muscle creatine kinase and myosin heavy chain were downregulated. The muscle regulatory factors were also silenced in myotubes infected with adenovirus E1A mutants incapable of reactivating the cell cycle in terminally differentiated muscle cells. Thus, the suppression of the differentiation program is not a consequence of cell cycle reactivation in myotubes, and it is induced by an independent mechanism. Our results show that E1A reactivates the cell cycle and suppresses tissue-specific gene expression in terminally differentiated muscle cells, thus causing dedifferentiation.

scholarly journals MiR-96-5p Induced by Palmitic Acid Suppresses the Myogenic Differentiation of C2C12 Myoblasts by Targeting FHL1

2020 ◽  
Vol 21 (24) ◽  
pp. 9445
Author(s):  
Mai Thi Nguyen ◽  
Kyung-Ho Min ◽  
Wan Lee
Keyword(s):  
Cell Cycle ◽  
Palmitic Acid ◽  
Transcriptional Activation ◽  
Morphological Changes ◽  
Myogenic Differentiation ◽  
Saturated Fatty Acids ◽  
Critical Role ◽  
C2c12 Myoblasts ◽  
Multi Stage ◽  
Myogenic Factors

Skeletal myogenesis is a multi-stage process that includes the cell cycle exit, myogenic transcriptional activation, and morphological changes to form multinucleated myofibers. Recent studies have shown that saturated fatty acids (SFA) and miRNAs play crucial roles in myogenesis and muscle homeostasis. Nevertheless, the target molecules and myogenic regulatory mechanisms of miRNAs are largely unknown, particularly when myogenesis is dysregulated by SFA deposition. This study investigated the critical role played by miR-96-5p on the myogenic differentiation in C2C12 myoblasts. Long-chain SFA palmitic acid (PA) significantly reduced FHL1 expression and inhibited the myogenic differentiation of C2C12 myoblasts but induced miR-96-5p expression. The knockdown of FHL1 by siRNA stimulated cell proliferation and inhibited myogenic differentiation of myoblasts. Interestingly, miR-96-5p suppressed FHL1 expression by directly targeting the 3’UTR of FHL1 mRNA. The transfection of an miR-96-5p mimic upregulated the expressions of cell cycle-related genes, such as PCNA, CCNB1, and CCND1, and increased myoblast proliferation. Moreover, the miR-96-5p mimic inhibited the expressions of myogenic factors, such as myoblast determination protein (MyoD), myogenin (MyoG), myocyte enhancer factor 2C (MEF2C), and myosin heavy chain (MyHC), and dramatically impeded differentiation and fusion of myoblasts. Overall, this study highlights the role of miR-96-5p in myogenesis via FHL1 suppression and suggests a novel regulatory mechanism for myogenesis mediated by miRNA in a background of obesity.

scholarly journals Histone Deacetylation of RB-Responsive Promoters: Requisite for Specific Gene Repression but Dispensable for Cell Cycle Inhibition

2003 ◽  
Vol 23 (21) ◽  
pp. 7719-7731 ◽  
Author(s):  
Hasan Siddiqui ◽  
David A. Solomon ◽  
Ranjaka W. Gunawardena ◽  
Ying Wang ◽  
Erik S. Knudsen
Keyword(s):  
Cell Cycle ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Cellular Proliferation ◽  
Trichostatin A ◽  
Critical Role ◽  
Histone Deacetylation ◽  
Specific Gene ◽  
Specific Subset ◽  
Cell Cycle Inhibition

ABSTRACT The retinoblastoma tumor suppressor protein (RB) is targeted for inactivation in the majority of human tumors, underscoring its critical role in attenuating cellular proliferation. RB inhibits proliferation by repressing the transcription of genes that are essential for cell cycle progression. To repress transcription, RB assembles multiprotein complexes containing chromatin-modifying enzymes, including histone deacetylases (HDACs). However, the extent to which HDACs participate in transcriptional repression and are required for RB-mediated repression has not been established. Here, we investigated the role of HDACs in RB-dependent cell cycle inhibition and transcriptional repression. We find that active RB mediates histone deacetylation on cyclin A, Cdc2, topoisomerase IIα, and thymidylate synthase promoters. We also demonstrate that this deacetylation is HDAC dependent, since the HDAC inhibitor trichostatin A (TSA) prevented histone deacetylation at each promoter. However, TSA treatment blocked RB repression of only a specific subset of genes, thereby demonstrating that the requirement of HDACs for RB-mediated transcriptional repression is promoter specific. The HDAC-independent repression was not associated with DNA methylation or gene silencing but was readily reversible. We show that this form of repression resulted in altered chromatin structure and was dependent on SWI/SNF chromatin remodeling activity. Importantly, we find that cell cycle inhibitory action of RB is not intrinsically dependent on the ability to recruit HDAC activity. Thus, while HDACs do play a major role in RB-mediated repression, they are dispensable for the repression of critical targets leading to cell cycle arrest.

scholarly journals Mdm4 (Mdmx) Regulates p53-Induced Growth Arrest and Neuronal Cell Death during Early Embryonic Mouse Development

2002 ◽  
Vol 22 (15) ◽  
pp. 5527-5538 ◽  
Author(s):  
Domenico Migliorini ◽  
Eros Lazzerini Denchi ◽  
Davide Danovi ◽  
Aart Jochemsen ◽  
Manuela Capillo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Critical Role ◽  
Neural Tube Closure ◽  
Negative Regulator ◽  
Nuclear Antigen ◽  
Deficiency Anemia ◽  
Specific Gene ◽  
Mouse Development ◽  
Embryonic Mouse

ABSTRACT We report here the characterization of a mutant mouse line with a specific gene trap event in the Mdm4 locus. Absence of Mdm4 expression results in embryonic lethality (10.5 days postcoitum [dpc]), which was rescued by transferring the Mdm4 mutation into a Trp53-null background. Mutant embryos were characterized by overall growth deficiency, anemia, improper neural tube closure, and dilation of lateral ventricles. In situ analysis demonstrated increased levels of p21CIP1/Waf1 and lower levels of Cyclin E and proliferating cell nuclear antigen expression. Consistent with lack of 5-bromo-2′-deoxyuridine incorporation, these data suggest a block of mutant embryo cells in the G1 phase of the cell cycle. Accordingly, Mdm4-deficient mouse embryonic fibroblasts manifested a greatly reduced proliferative capacity in culture. Moreover, extensive p53-dependent cell death was specifically detected in the developing central nervous system of the Mdm4 mutant embryos. These findings unambiguously assign a critical role for Mdm4 as a negative regulator of p53 and suggest that Mdm4 could contribute to neoplasias retaining wild-type Trp53. Finally, we provide evidence indicating that Mdm4 plays no role on cell proliferation or cell cycle control that is distinct from its ability to modulate p53 function.

scholarly journals Bmi1 Augments Proliferation and Survival of Cortical Bone-Derived Stem Cells after Injury through Novel Epigenetic Signaling via Histone 3 Regulation

2021 ◽  
Vol 22 (15) ◽  
pp. 7813
Author(s):  
Lindsay Kraus ◽  
Chris Bryan ◽  
Marcus Wagner ◽  
Tabito Kino ◽  
Melissa Gunchenko ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Dna Damage ◽  
Stem Cell ◽  
Histone Modification ◽  
Epigenetic Regulation ◽  
Critical Role ◽  
Proliferative Potential ◽  
Therapeutic Effects ◽  
Histone 3

Ischemic heart disease can lead to myocardial infarction (MI), a major cause of morbidity and mortality worldwide. Multiple stem cell types have been safely transferred into failing human hearts, but the overall clinical cardiovascular benefits have been modest. Therefore, there is a dire need to understand the basic biology of stem cells to enhance therapeutic effects. Bmi1 is part of the polycomb repressive complex 1 (PRC1) that is involved in different processes including proliferation, survival and differentiation of stem cells. We isolated cortical bones stem cells (CBSCs) from bone stroma, and they express significantly high levels of Bmi1 compared to mesenchymal stem cells (MSCs) and cardiac-derived stem cells (CDCs). Using lentiviral transduction, Bmi1 was knocked down in the CBSCs to determine the effect of loss of Bmi1 on proliferation and survival potential with or without Bmi1 in CBSCs. Our data show that with the loss of Bmi1, there is a decrease in CBSC ability to proliferate and survive during stress. This loss of functionality is attributed to changes in histone modification, specifically histone 3 lysine 27 (H3K27). Without the proper epigenetic regulation, due to the loss of the polycomb protein in CBSCs, there is a significant decrease in cell cycle proteins, including Cyclin B, E2F, and WEE as well as an increase in DNA damage genes, including ataxia-telangiectasia mutated (ATM) and ATM and Rad3-related (ATR). In conclusion, in the absence of Bmi1, CBSCs lose their proliferative potential, have increased DNA damage and apoptosis, and more cell cycle arrest due to changes in epigenetic modifications. Consequently, Bmi1 plays a critical role in stem cell proliferation and survival through cell cycle regulation, specifically in the CBSCs. This regulation is associated with the histone modification and regulation of Bmi1, therefore indicating a novel mechanism of Bmi1 and the epigenetic regulation of stem cells.

scholarly journals Coculture with hiPS-derived intestinal cells enhanced human hepatocyte functions in a pneumatic-pressure-driven two-organ microphysiological system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marie Shinohara ◽  
Hiroshi Arakawa ◽  
Yuuichi Oda ◽  
Nobuaki Shiraki ◽  
Shinji Sugiura ◽  
...  
Keyword(s):  
Normal Cell ◽  
Human Hepatocytes ◽  
New Drugs ◽  
Intestinal Cells ◽  
Specific Gene ◽  
Gene Expressions ◽  
Normal Cells ◽  
Pneumatic Pressure ◽  
Pressure Driven

AbstractExamining intestine–liver interactions is important for achieving the desired physiological drug absorption and metabolism response in in vitro drug tests. Multi-organ microphysiological systems (MPSs) constitute promising tools for evaluating inter-organ interactions in vitro. For coculture on MPSs, normal cells are challenging to use because they require complex maintenance and careful handling. Herein, we demonstrated the potential of coculturing normal cells on MPSs in the evaluation of intestine–liver interactions. To this end, we cocultured human-induced pluripotent stem cell-derived intestinal cells and fresh human hepatocytes which were isolated from PXB mice with medium circulation in a pneumatic-pressure-driven MPS with pipette-friendly liquid-handling options. The cytochrome activity, albumin production, and liver-specific gene expressions in human hepatocytes freshly isolated from a PXB mouse were significantly upregulated via coculture with hiPS-intestinal cells. Our normal cell coculture shows the effects of the interactions between the intestine and liver that may occur in vivo. This study is the first to demonstrate the coculturing of hiPS-intestinal cells and fresh human hepatocytes on an MPS for examining pure inter-organ interactions. Normal-cell coculture using the multi-organ MPS could be pursued to explore unknown physiological mechanisms of inter-organ interactions in vitro and investigate the physiological response of new drugs.

scholarly journals Cell Cycle-Dependent Expression of Mammalian E2-C Regulated by the Anaphase-Promoting Complex/Cyclosome

2000 ◽  
Vol 11 (8) ◽  
pp. 2821-2831 ◽  
Author(s):  
Atsushi Yamanaka ◽  
Shigetsugu Hatakeyama ◽  
Kin-ichiro Kominami ◽  
Masatoshi Kitagawa ◽  
Masaki Matsumoto ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Substrate Specificity ◽  
Critical Role ◽  
Anaphase Promoting Complex ◽  
Polyubiquitin Chain ◽  
M Phase ◽  
Ubiquitin Conjugating Enzyme ◽  
Recognition Motifs ◽  
Cycle Dependent ◽  
Conjugating Enzyme

Progression through mitosis requires the precisely timed ubiquitin-dependent degradation of specific substrates. E2-C is a ubiquitin-conjugating enzyme that plays a critical role with anaphase-promoting complex/cyclosome (APC/C) in progression of and exit from M phase. Here we report that mammalian E2-C is expressed in late G2/M phase and is degraded as cells exit from M phase. The mammalian E2-C shows an autoubiquitinating activity leading to covalent conjugation to itself with several ubiquitins. The ubiquitination of E2-C is strongly enhanced by APC/C, resulting in the formation of a polyubiquitin chain. The polyubiquitination of mammalian E2-C occurs only when cells exit from M phase. Furthermore, mammalian E2-C contains two putative destruction boxes that are believed to act as recognition motifs for APC/C. The mutation of this motif reduced the polyubiquitination of mammalian E2-C, resulting in its stabilization. These results suggest that mammalian E2-C is itself a substrate of the APC/C-dependent proteolysis machinery, and that the periodic expression of mammalian E2-C may be a novel autoregulatory system for the control of the APC/C activity and its substrate specificity.

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