title: Bioimaging of microRNA124a-independent neuronal differentiation of human G2 neural stem cells.
abstract: Evaluation of the function of microRNAs (miRNAs or miRs) through miRNA expression profiles during neuronal differentiation plays a critical role not only in identifying unique miRNAs relevant to cellular development but also in understanding regulatory functions of the cell-specific miRNAs in living organisms. Here, we examined the microarray-based miRNA expression profiles of G2 cells (recently developed human neural stem cells) and monitored the expression pattern of known neuron-specific miR-9 and miR-124a during neuronal differentiation of G2 cells in vitro and in vivo. Of 500 miRNAs analyzed by microarray of G2 cells, the expression of 90 miRNAs was significantly increased during doxycycline-dependent neuronal differentiation of G2 cells and about 60 miRNAs showed a gradual enhancement of gene expression as neuronal differentiation progressed. Real-time PCR showed that expression of endogenous mature miR-9 was continuously and gradually increased in a pattern dependent on the period of neuronal differentiation of G2 cells while the increased expression of neuron-specific mature miR-124a was barely observed during neurogenesis. Our recently developed miRNA reporter imaging vectors (CMV/Gluc/3×PT_miR-9 and CMV/Gluc/3×PT_miR-124a) containing Gaussia luciferase, CMV promoter and three copies of complementary nucleotides of each corresponding miRNA showed that luciferase activity from CMV/Gluc/3×PT_miR-9 was gradually decreased both in vitro and in vivo in G2 cells induced to differentiate into neurons. However, in vitro and in vivo bioluminescence signals for CMV/Gluc/3×PT_miR-124a were not significantly different between undifferentiated and differentiated G2 cells. Our results demonstrate that biogenesis of neuron-specific miR-124a is not necessary for doxycycline-dependent neurogenesis of G2 cells.
authors.affiliation: Institute for Bio-Medical Convergence, College of Medicine, Catholic Kwandong University, Gangneung-si, Gangwon-do 270-701, Republic of Korea ; Catholic Kwandong University International St. Mary's Hospital, Incheon Metropolitan City 404-834, Republic of Korea.
authors.forename: Jonghwan
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 151-747, Republic of Korea ; Institute of Nuclear Medicine, Medical Research Center, Seoul 110-744, Republic of Korea.
authors.forename: Do Won
authors.initials: DW
authors.lastname: Hwang
authors.affiliation: Department of Neuroscience, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, United States.
authors.forename: Seung U
authors.initials: SU
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 151-747, Republic of Korea ; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Institute for Bio-Medical Convergence, College of Medicine, Catholic Kwandong University, Gangneung-si, Gangwon-do 270-701, Republic of Korea ; Catholic Kwandong University International St. Mary's Hospital, Incheon Metropolitan City 404-834, Republic of Korea.
authors.forename: Yong Seung
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Institute for Bio-Medical Convergence, College of Medicine, Catholic Kwandong University, Gangneung-si, Gangwon-do 270-701, Republic of Korea ; Catholic Kwandong University International St. Mary's Hospital, Incheon Metropolitan City 404-834, Republic of Korea.
authors.forename: Hyejung
authors.initials: H
authors.lastname: Heo
authors.affiliation: Al-Jeraisy DNA Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia ; Department of Nucleic Acids Research, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technological Applications, Alexandria 21934, Egypt.
authors.forename: Bahy A
authors.initials: BA
authors.lastname: Ali
authors.affiliation: Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Al-Khedhairy
authors.affiliation: Institute for Bio-Medical Convergence, College of Medicine, Catholic Kwandong University, Gangneung-si, Gangwon-do 270-701, Republic of Korea ; Catholic Kwandong University International St. Mary's Hospital, Incheon Metropolitan City 404-834, Republic of Korea.
authors.forename: Soonhag
authors.initials: S
authors.lastname: Kim
keywords: Fluc, Firefly Luciferase; G2 human neural stem cells; Gluc, Gaussia luciferase; In vivo imaging; Neuronal differentiation; Reporter gene; miR, microRNA; microRNAs