1 Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Roudebush Veterans Administration Medical Center, Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, USA. Electronic address: lplotkin@iupui.edu.
2 Center for Regenerative Medicine and Skeletal Development, UConn Health, Farmington, CT 06032, USA. Electronic address: ikalaj@uchc.edu.