1. Department of Neurology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, People's Republic of China.
2. Center for Stem Cell Biology and Tissue Engineering, Sun Yat-sen University, Guangzhou 510080, People's Republic of China.
3. State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
4. Laboratory of Physiology, Life Sciences School, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
5. Department of Neurology, University of Washington School of Medicine, Seattle, WA 98195.