1 Guangzhou National Laboratory, Guangzhou Medical University, Guangzhou, China.
2 Center for Cell Lineage and Development, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangdong-Hong Kong Joint Laboratory for Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China. chen_jiekai@gibh.ac.cn.