1 Vascular Biology Research Institute, Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou 510006, China.
2 Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College of Jinan University, Guangzhou 510632, China.
3 Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA.