Roles of transforming growth factor-β1 and OB-cadherin in porcine cardiac valve myofibroblast differentiation

Calcific aortic stenosis is a common disease, and some of its early causes are the activation and differentiation of resident fibroblasts to myofibroblasts in response to transforming growth factor beta 1 (TGF-beta 1). The aim of this study was to understand how TGF-beta 1 and its downstream effector, OB-cadherin [cadherin 11 (CDH11)], regulate porcine myofibroblast phenotypes. Based on whole-genome microarrays, 95 and 107 genes are up-and down-regulated at both the early (8 h) and the late (24 h) time points of TGF-beta 1 treatment. Gene functions related to cell adhesion, skeletal system development, and extracellular matrix are up-regulated by TGF-beta 1, whereas oxidation-reduction and steroid metabolic process are down-regulated. Notably, one of the cell adhesion molecules, CDH11, is up-regulated by similar to 2-fold through both the Smad2/3 and the ERK pathways elicited by TGF-beta 1. CDH11 mediates cell-cell contacts in both valvular fibroblasts and myofibroblasts. Knockdown of CDH11 by small interfering RNA increases the myofibroblast phenotype, including an similar to 2-fold increase in alpha-smooth muscle actin (alpha-SMA) expression and stress fiber formation. In contrast, increased binding of CDH11 through antibody treatment inhibits alpha-SMA expression. This study presents gene functional changes in response to TGF-beta 1 at the systems level and supports an inhibitory role of CDH11 in myofibroblast differentiation.