Overexpression of connexin 43 in skeletal myoblasts: Relevance to cell transplantation to the heart

Suzuki, Ken; Brand, Nigel J.; Allen, Stuart; Khan, Muhammad; Farrell, Aldo; Murtuza, Bari; Oakley, Reida El; Yacoub, Magdi H.

doi:10.1067/mtc.2001.116210

Cited by 82 publications

(56 citation statements)

References 16 publications

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“…Our data contrast somewhat with a previous study by Suzuki and colleagues, who also sought to enhance intercellular communication of skeletal with cardiac myocytes (Suzuki et al, 2001). These authors overexpressed Cx43 in L6 rat skeletal myoblasts, using the human CMV promoter, the same promoter used in our adenovirus approach.…”

Section: Discussioncontrasting

confidence: 55%

Gene Transfer of Connexin43 into Skeletal Muscle

et al. 2004

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Cellular cardiomyoplasty using skeletal myoblasts may be beneficial for infarct repair. One drawback to skeletal muscle cells is their lack of gap junction expression after differentiation, thus preventing electrical coupling to host cardiomyocytes. We sought to overexpress the gap junction protein connexin43 (Cx43) in differentiated skeletal myotubes, using retroviral, adenoviral, and plasmid-mediated gene transfer. All strategies resulted in overexpression of Cx43 in cultured myotubes, but expression of Cx43 from constitutive viral promoters caused significant death upon differentiation. Dye transfer studies showed that surviving myotubes contained functional gap junctions, however. Retrovirally transfected myoblasts did not express Cx43 after grafting into the heart, possibly due to promoter silencing. Adenovirally transfected myoblasts expressed abundant Cx43 after forming myotubes in cardiac grafts, but grafts showed signs of injury at 1 week and had died by 2 weeks. Interestingly, transfection of already differentiated myotubes with adenoviral Cx43 was nontoxic, implying a window of vulnerability during differentiation. To test this hypothesis, Cx43 was expressed from the muscle creatine kinase (MCK) promoter, which is active only after myocyte differentiation. The MCK promoter resulted in high levels of Cx43 expression in differentiated myotubes but did not cause cell death during differentiation. MCK-Cx43-transfected myoblasts formed viable cardiac grafts and, in some cases, Cx43-expressing myotubes were in close apposition to host cardiomyocytes, possibly allowing electrical coupling. Thus, high levels of Cx43 during skeletal muscle differentiation cause cell death. When, however, expression of Cx43 is delayed until after differentiation, using the MCK promoter, myotubes are viable and express gap junction proteins after grafting in the heart. This strategy may permit electrical coupling of skeletal and cardiac muscle for cardiac repair. OVERVIEW SUMMARYCellular cardiomyoplasty using skeletal myoblasts may be beneficial for infarct repair. Differentiated skeletal muscle, however, lacks gap junction expression, thus preventing electrical coupling to host myocardium. We sought to overexpress the gap junction protein connexin43 (Cx43) in differentiated skeletal myotubes, using retroviral, adenoviral, and plasmid-mediated gene transfer. All strategies resulted in overexpression of Cx43 in cultured myotubes, but expression of Cx43 from constitutive viral promoters caused significant death upon differentiation. Retrovirally transfected myoblasts did not express Cx43 after grafting into the heart. Adenovirally transfected myoblasts expressed abundant Cx43 in cardiac grafts, but grafts showed signs of cell death. Interestingly, transfection of differentiated myotubes with adenoviral Cx43 was nontoxic, implying a window of vulnerability during differentiation. Therefore, Cx43 was expressed from the muscle creatine kinase (MCK) promoter, which is active only after myocyte differentiation. The MCK promoter...

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Section: Discussioncontrasting

confidence: 55%

Gene Transfer of Connexin43 into Skeletal Muscle

et al. 2004

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“…Several remedial approaches have been employed including transfection of SkMs with the appropriate genes such as encoding Cx43 [Suzuki et al, 2001;Stagg et al, 2006], vascular endothelial growth factor (VEGF) [Retuerto et al, 2007], insulin-like growth factor-1 [Kanemitsu et al, 2006], hepatocyte growth factor [Tambara et al, 2005] and heat shock protein [Suzuki et al, 2000] prior to transplantation. Although cell-based gene therapy may have a synergistic beneficial effect on the improvement in cardiac function, one should be cautious regarding the issues associated with gene therapy, which may hamper a wide-scale clinical application of these approaches [Heng et al, 2005].…”

Section: Introductionmentioning

confidence: 99%

Lithium Chloride Preconditioning Optimizes Skeletal Myoblast Functions for Cellular Cardiomyoplasty in vitro via Glycogen Synthase Kinase-3β/β-Catenin Signaling

Li²,

Wang³

et al. 2008

Cells Tissues Organs

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The benefits of skeletal myoblast (SkM) transplantation for cardiomyoplasty are limited due to their decreased functional integration with host cardiomyocytes and the poor survival of implanted cells in ischemic hearts. However, little success has been achieved with respect to the strategies aiming to improve the efficiency of SkM transplantation. In this study, we demonstrated that LiCl-preconditioned SkMs resulted in significantly increased connexin 43 (Cx43) expression and gap-junctional communication with cardiomyocytes. Vascular endothelial growth factor (VEGF) expression of SkMs was significantly upregulated in response to LiCl. Furthermore, hydrogen peroxide induced SkM apoptosis and increased caspase-3 expression, whereas LiCl inhibited SkM apoptosis, resulted in the decrease of caspase-3 expression and promoted SkM proliferation. These effects of LiCl were mediated by inactivating glycogen synthase kinase-3β (GSK-3β), stabilizing the effector protein β-catenin and translocating it into the nucleus of SkMs, confirming that LiCl mimics canonical Wnt signaling. These findings suggest that LiCl preconditioning may be a novel strategy to optimize SkM function for cellular cardiomyoplasty in vitro.

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“…Electrical coupling does occur in vitro (10,14,28) but has seriously been questioned in vivo (16,17,34). This problem can possibly be overcome by genetic modification of skeletal muscle cells to overexpress the cardiac gap junction protein connexin43 (30,40), which may permit electrical coupling to cardiomyocytes (30,39). Notably, such an induced coupling may only be beneficial for the heart if the skeletal muscle graft indeed exhibits cardiac-like ion channel properties.…”

Section: Discussionmentioning

confidence: 99%

C₂C₁₂ skeletal muscle cells adopt cardiac-like sodium current properties in a cardiac cell environment

Zebedin¹,

Mille²,

Speiser³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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Intracardiac transplantation of undifferentiated skeletal muscle cells (myoblasts) has emerged as a promising therapy for myocardial infarct repair and is already undergoing clinical trials. The fact that cells originating from skeletal muscle have different electrophysiological properties than cardiomyocytes, however, may considerably limit the success of this therapy and, in addition, cause side effects. Indeed, a major problem observed after myoblast transplantation is the occurrence of ventricular arrhythmias. The most often transient nature of these arrhythmias may suggest that, once transplanted into cardiac tissue, skeletal muscle cells adopt more cardiac-like electrophysiological properties. To test whether a cardiac cell environment can indeed modify electrophysiological parameters of skeletal muscle cells, we treated mouse C2C12 myocytes with medium preconditioned by primary cardiocytes and compared their functional sodium current properties with those of control cells. We found this treatment to significantly alter the activation and inactivation properties of sodium currents from “skeletal muscle” to more “cardiac”-like ones. Sodium currents of cardiac-conditioned cells showed a reduced sensitivity to block by tetrodotoxin. These findings and reverse transcription PCR experiments suggest that an upregulation of the expression of the cardiac sodium channel isoform Nav1.5 versus the skeletal muscle isoform Nav1.4 is responsible for the observed changes in sodium current function. We conclude that cardiomyocytes alter sodium channel isoform expression of skeletal muscle cells via a paracrine mechanism. Thereby, skeletal muscle cells with more cardiac-like sodium current properties are generated.

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Overexpression of connexin 43 in skeletal myoblasts: Relevance to cell transplantation to the heart

Cited by 82 publications

References 16 publications

Gene Transfer of Connexin43 into Skeletal Muscle

Gene Transfer of Connexin43 into Skeletal Muscle

Lithium Chloride Preconditioning Optimizes Skeletal Myoblast Functions for Cellular Cardiomyoplasty in vitro via Glycogen Synthase Kinase-3β/β-Catenin Signaling

C₂C₁₂ skeletal muscle cells adopt cardiac-like sodium current properties in a cardiac cell environment

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Overexpression of connexin 43 in skeletal myoblasts: Relevance to cell transplantation to the heart

Cited by 82 publications

References 16 publications

Gene Transfer of Connexin43 into Skeletal Muscle

Gene Transfer of Connexin43 into Skeletal Muscle

Lithium Chloride Preconditioning Optimizes Skeletal Myoblast Functions for Cellular Cardiomyoplasty in vitro via Glycogen Synthase Kinase-3β/β-Catenin Signaling

C2C12 skeletal muscle cells adopt cardiac-like sodium current properties in a cardiac cell environment

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C₂C₁₂ skeletal muscle cells adopt cardiac-like sodium current properties in a cardiac cell environment