Ryuji Morizane1,2,3,4. 1. Renal Division, Brigham and Women's Hospital, Boston, MA, USA. morizanr@da2.so-net.ne.jp. 2. Department of Medicine, Harvard Medical School, Boston, MA, USA. morizanr@da2.so-net.ne.jp. 3. Harvard Stem Cell Institute, Cambridge, MA, USA. morizanr@da2.so-net.ne.jp. 4. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA. morizanr@da2.so-net.ne.jp.