抄録
Neural stem (progenitor) cells (NSCs) differentiate to neurons, astrocytes and oligodendrocytes. From the viewpoint of differentiation to neurons, the regulation of cell cycle in NSCs seems to be important. However, how cell cycle relates to neuronal differentiation is poorly understood. We investigated whether NSCs derived from E12.5 rat ventral mesencephalon can efficiently differentiate into neurons or not under the control of cell cycle. We first checked the toxicity (optimal concentration and duration of treatment) of cell cycle blockers (agent that blocked before G1/S phase, S and G2/M). FACScan analysis showed that G1 phase blockers such as mimosine (100 μM, 8 h), deferoxamine (500 μM, 8 h) and aphidicolin (1.5 μM, 8 h) blocked NSCs proliferation without cell toxicity. BrdU analysis showed that BrdU-positive cells (proliferationg NSCs) were significantly decreased compared with non treated ones. When NSCs were blocked their cell cycle in the G1 phase and were differentiated in DMEM/F12+1% FCS for 3days, the numbers of β-tubulin III-positive cells were increased to approximately twice compared with non-treated ones. By the treatment the mRNA of MAP-2 was increased while that of S-100 was not changed. Western immunoblot analysis showed the increase of MAP-2 protein and decrease of GFAP protein. No programmed cell death was detected by TUNEL reaction. Data suggest that, by the treatment with the G1 phase blockers, NSCs were promoted to differentiate to neural phenotype without apoptosis. [Jpn J Physiol 54 Suppl:S157 (2004)]
