Invited Speaker Abstract 2018 Hunter Cell Biology Meeting

NKX2-5 regulates human cardiomyogenesis via a HEY2-dependent transcriptional network   (#58)

David Elliott 1 , David Anderson 1 , David Kaplan 2 , Katrina Bell 1 , John Haynes 3 , Richard Mills 4 , James Hudson 4 , Enzo Porrello 1 , Mauro Costa 5 , Richard Harvey 6 , Alicia Oshlack 1 , Michael Cheung 1 7 , Steve Petrou 2 , Christine Mummery 8 , Andrew Elefanty 1 , Ed Stanley 1
  1. Murdoch Childrens Research Institute, Parkville, VIC, Australia
  2. Florey Institute of Neuroscience and Mental Health, Parkville, Vic, Australia
  3. Monash University , Parkville, Vic, Australia
  4. University of Queensland, Brisbane, Qld, Australia
  5. JAX Laboratories, Bar Harbor, MA, USA
  6. The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
  7. Royal Childrens Hospital , Parkville, Vic, Australia
  8. Leiden University Medical Centre, Leiden, Netherlands

The differentiation of human pluripotent stem cells (hPSCs) to the cardiac lineage can be used to model human heart development and, in turn, to analyze the developmental consequences of genetic abnormalities. NKX2-5 encodes a highly conserved homeobox transcription factor that is an ancient and critical component of the vertebrate cardiac gene regulatory network. Here, we use genetically modified human embryonic stem cell (hESC) lines to elucidate NKX2-5 function in early heart development. Cardiomyocytes derived from NKX2-5 null hPSCs fail to up-regulate VCAM1, a marker of cardiac differentiation, and maintain expression of PDGFRA, indicating a failure to complete cardiomyogenesis. Furthermore, NKX2-5 null cardiac monolayers display asynchronous contraction and individual mutant cardiomyocytes have altered electrophysiology. Molecular profiling by RNA-seq and ChIP-seq demonstrates that NKX2-5 has an important role in regulating the maturation of cardiomyocytes and expression of key calcium handling, ion channel and gap junction associated genes. Furthermore, genetic rescue experiments demonstrate that the bHLH protein HEY2 is a key mediator of NKX2-5 function during human cardiomyogenesis. These findings identify HEY2 as a novel component of the NKX2-5 cardiac transcriptional network, providing tangible evidence that hESC models can decipher the complex pathways that regulate early stage human heart development. These data provide a human context for the evaluation of pathogenic mutations in congenital heart disease.