1 Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. Electronic address: kazuo.takayama@cira.kyoto-u.ac.jp.
2 Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan; CiRA Foundation, Kyoto, Japan; Gladstone Institute of Cardiovascular Disease, San Francisco, USA. Electronic address: yamanaka@cira.kyoto-u.ac.jp.