Sinoatrial node cardiomyocytes derived from human pluripotent cells function as a biological pacemaker

Developers

Stephanie I Protze, Jie Liu, Lior Gepstein, Gordon M Keller, etc.

Description of the technology

The sinoatrial node (SAN) is the primary pacemaker of the heart and controls heart rate throughout life. Failure of SAN function due to congenital disease or aging results in slowing of the heart rate and inefficient blood circulation, a condition treated by implantation of an electronic pacemaker. The ability to produce pacemaker cells in vitro could lead to an alternative, biological pacemaker therapy in which the failing SAN is replaced through cell transplantation.

Here we describe a transgene-independent method for the generation of SAN-like pacemaker cells (SANLPCs) from human pluripotent stem cells by stage-specific manipulation of developmental signaling pathways. It was found that BMP (bone morphogenic proteins) signaling specifies cardiac mesoderm toward the SANLPC fate, whereas RA (retinoic acid) signaling enhances the pacemaker phenotype. It was also showed that staged inhibition of the FGF (fibroblast growth factor) pathway blocks the development of NKX2-5+ cardiomyocytes and facilitates enrichment of SANLPCs from non-modified hPSC lines. In sum, this strategy allows generating unlimited numbers of SANLPCs from any hPSC line. These findings is valuable to model heart diseases with SAN dysfunction in pathogenesis using patient-derived iPSCs and to generate unlimited number of SANLPCs for developing clinically compliant biological pacemakers. Produced SANLPCs display molecular, electrophysiological and functional properties of human SAN pacemaker cells. SANLPCs are identified as NKX2-5−cardiomyocytes that express markers of the SAN lineage and display typical pacemaker action potentials, ion current profiles and chronotropic responses. When transplanted into the apex of rat hearts, SANLPCs are able to pace the host heart tissue, demonstrating their capacity to function as a biological pacemaker.

Practical application

The technology provides an opportunity to generate functional SANLPCs from hPSCs and to study human pacemaker development and function, to model diseases that affect this type of cardiomyocytes and to design cell-based therapies for patients with SAN dysfunction.

Proposed transgene-independent differentiation protocol will facilitate the development of biological pacemakers for such therapies. The technology enables the generation of unlimited numbers of non-genetically altered SANLPCs for testing long-term functioning and safety in large-animal models.

Laboratories

• McEwen Centre for Regenerative Medicine and Princess Margaret Cancer Center, University Health Network, Toronto (Canada)
• Department of Medical Biophysics, University of Toronto (Canada)
• The Sohnis Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa (Israel)
• Department of Internal Medicine A, Rappaport Faculty of Medicine and Research Institute and Rambam Health Care Campus, Technion-Israel Institute of Technology, Haifa (Israel)

Links

Publications

• Protze, S.I. «Sinoatrial node cardiomyocytes derived from human pluripotent cells function as a biological pacemaker." Nat Biotechnol. 2016 Dec 12. doi: 10.1038/nbt.3745. [Advance online publication].
• Liu, J. et al. «Dissection of the voltage-activated potassium outward currents in adult mouse ventricular myocytes: l(to,f), l(to,s), I(K,slow1), I(K,slow2), and l(ss)." 106 Basic Res. Cardio. (2011): 189–204.
• Kennedy, M. et al. «Development of the hemangioblast defines the onset of hematopoiesis in human ES cell differentiation cultures." 109 Blood (2007): 2679–2687.