Vang-like 2 and Noncanonical Wnt Signaling In Outflow Tract Development

Despite rapid advances in cardiovascular developmental genetics, the precise morphogenetic processes that coordinate heart development, and the genes and signaling pathways that regulate them remain unclear. In this review, we describe a highly conserved signaling pathway, the noncanonical Wnt (planar cell polarity) pathway, and its relationship to cardiovascular development and congenital heart defects. This pathway regulates cell polarity and polarized cell movements in a variety of contexts. Mutations in several genes in this pathway and specifically in the Vang-like 2 (Vangl2) (strabismus) gene, result in abnormalities in the remodeling of the outflow tract and, ultimately, in the cardiac alignment defect double-outlet right ventricle. Polarized cell migration of cardiomyocytes into the outflow tract cushions is inhibited when Vangl2 function is disturbed, suggesting that the noncanonical Wnt pathway may regulate this aspect of outflow tract remodeling. These studies suggest that mutations in Vangl2 and other components of the noncanonical Wnt pathway, may be candidates for causing congenital outflow tract defects in humans.