Abstract 14887: A Connexin43 CT-Mimetic Peptide Increases Fibroblast Migration in an in vitro Model of the Injury Border Zone
Connexins have been shown to affect the growth and migration of cells both in vivo and in vitro. A connexin43 (Cx43) carboxyl-terminus (CT) mimetic peptide (αCT1), incorporating a ZO-1-PDZ-binding domain, increases gap junction size via reduced Cx43/ZO-1 interaction in vitro and decreases scarring in cutaneous wounds in vivo. We previously reported the effects of αCT1-treatment in a left ventricular (LV) cryoinjury model in vivo. At 8-weeks after cryoinjury, histological assessment of scars showed decreases in scar size and increases in collagen fibril uniformity in αCT1-treated hearts versus controls. Furthermore, interdigitation of collagen, periostin, and non-myocardial fibroblastic cells between myocytes in the injury border zone (IBZ) was reduced in treated hearts versus controls. To assess the hypothesis that the Cx43 CT affects fibroblast migration post-MI, we created a 3D heterocellular system to model the IBZ in vitro. Percoll gradient-purified myocytes from neonatal rats were seeded into 96-well non-adhesive agarose micromolds, where they formed core spheroids over 48 hours. A layer of neonatal cardiac fibroblasts was seeded to form a shell around the myocyte core spheroids. Cell spheroids were treated with 100 μM αCT1 or appropriate controls. Changes in relative locations of myocytes and fibroblasts over time were observed using red/green CellTracker labeling and confocal live cell imaging. Quantitative analyses of cell locations over a 72 hour time course demonstrated that treatment of aggregates induced fibroblasts to migrate to the center of aggregates, displacing the myocytes, to a larger extent than in control conditions (p<0.05, n=3). Studies of an in vivo LV cryoinjury model were used to validate these data. In sum, our results indicate the potential for Cx43 CT effects on fibroblast motility and heterocellular interactions with myocytes as factors in tissue organization of the injury border zone and scar following myocardial infarction.
- © 2013 by American Heart Association, Inc.