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Development 2009 Sep 01;13618:3185-93.
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Connexin 43 regulates epicardial cell polarity and migration in coronary vascular development.

Rhee DY , Zhao XQ , Francis RJ , Huang GY , Mably JD , Lo CW .

Connexin 43 knockout (Cx43 KO) mice exhibit conotruncal malformations and coronary artery defects. We observed epicardial blisters in the Cx43 KO hearts that suggest defects in epicardial epithelial-mesenchymal transformation (EMT), a process that generates coronary vascular progenitors. Analysis using a three-dimensional collagen gel invasion assay showed that Cx43 KO epicardial cells are less invasive and that, unlike wild-type epicardial cells, they fail to organize into thin vessel-like projections. Examination of Cx43 KO hearts using Wt1 as an epicardial marker revealed a disorganized pattern of epicardial cell infiltration. Time-lapse imaging and motion analysis using epicardial explants showed a defect in directional cell migration. This was associated with changes in the actin/tubulin cytoskeleton. A defect in cell polarity was indicated by a failure of the microtubule-organizing center to align with the direction of cell migration. Forced expression of Cx43 constructs in epicardial explants showed the Cx43 tubulin-binding domain is required for Cx43 modulation of cell polarity and cell motility. Pecam staining revealed early defects in remodeling of the primitive coronary vascular plexuses in the Cx43 KO heart. Together, these findings suggest an early defect in coronary vascular development arising from a global perturbation of the cytoarchitecture of the cell. Consistent with this, we found aberrant myocardialization of the outflow tract, a process also known to be EMT dependent. Together, these findings suggest cardiac defects in the Cx43 KO mice arise from the disruption of cell polarity, a process that may be dependent on Cx43-tubulin interactions.

PubMed ID: 19700622
PMC ID: PMC2730372

Species referenced: Xenopus
Genes referenced: actl6a frzb2 gja1 golga2 itk pecam1 wt1

Article Images: [+] show captions
References [+] :
Barker, Increased association of ZO-1 with connexin43 during remodeling of cardiac gap junctions. 2002, Pubmed