title: Rhotekin modulates differentiation of cultured neural stem cells to neurons.
abstract: Rhotekin is a downstream signal of Rho and is expressed in the central nervous system. However, the physiological role of rhotekin in the development of neural stem cells (NSCs) into neurons is unknown. In this study, we knocked down the expression of rhotekin protein with small interfering RNA (siRNA) in the NSCs and in neural differentiated cells and measured cell proliferation, differentiation, neurite length, and survival. By using immunocytochemistry and Western blot, the production of rhotekin was observed in NSCs and neuronal cells. Furthermore, rhotekin production was increased in accordance with neural differentiation. Rhotekin knock-down reduced 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) activity and increased the cell death 72 hr after transfection in neurons. On the other hand, in NSCs, rhotekin knock-down increased MTT activity and the number of 5-bromo-2'-deoxyuridine (BrdU)-positive cells. In the present study, we demonstrated that rhotekin is required for maintenance and survival of neurons and positively regulates differentiation and neurite outgrowth. Moreover, we found that rhotekin is produced in NSCs and that the role of rhotekin is to regulate cell proliferation negatively. In conclusion, these results suggest that rhotekin is one of the key molecules in the differentiation of NSCs into neurons.
authors.affiliation: Department of Psychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iwai
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Saitoh
authors.forename: Misa
authors.initials: M
authors.lastname: Yamada
authors.forename: Kou
authors.initials: K
authors.lastname: Takahashi
authors.forename: Eri
authors.initials: E
authors.lastname: Hashimoto
authors.forename: Wataru
authors.initials: W
authors.lastname: Ukai
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Saito
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Yamada
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology; D005260:Female; D019204:GTP-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000172:deficiency / Q000502:physiology*; D058953:Neural Stem Cells / Q000166:cytology / Q000378:metabolism*; D016501:Neurites / Q000502:physiology; D055495:Neurogenesis / Q000235:genetics / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D061251:Primary Cell Culture; D051381:Rats; D017208:Rats, Wistar
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C498396:Rtkn protein, rat; D019204:GTP-Binding Proteins