Mechanisms for cell signaling in the control of cardiomyogenesis

Project Summary/Abstract Down syndrome (DS), the condition caused by trisomy of human chromosome 21, affects approximately 1 in 700 newborns in the United States. Congenital heart defects (CHDs) are very frequent in children with DS with a prevalence of 50% compared to a risk of < 1 % in typical children. Although remarkable advances in health care and cardiac correction surgery have improved the survival rate of children born with DS, CH Ds are still a primary and significant risk factor for mortality in people with DS through age twenty. Using a combination of the human induced pluripotent stem cell (iPSC)-based model and Dp(16)1Yey/+ (Dp16), a mouse model for DS, we identified increased dosage of interferon (IFN) receptor encoded by genes, IFNAR1, IFNAR2, IFNG2, and IL10RB on chromosome 21 (chr21) as a causative factor of CHDs in DS. The canonical Wnt signaling pathway was down-regulated during DS cardiogenesis in vitro and in vivo. Normalization of I FN signaling restored the canonical Wnt pathway and ameliorated cardiogenesis in DS. In this project, we propose to (1) determine molecular mechanisms by which increased IFN signaling down-regulates the Wnt/β-Catenin pathway during heart development in DS and (2) examine cell populations associated with response to increased IFN signaling during heart development in DS. The results from this project have the potential to facilitate the development of novel therapeutic strategies to benefiting both people with DS and typical children born with CHDs.