[30]

Microgravity Inhibits Neural Differentiation While Sustaining The Capability of Differentiation.   A. Sasaki¹, M. Takeda², T. Magaki², S.L. Wu¹, Y. Kawahara^{1, 3}, R. Yoshimoto¹, T. Manabe¹, A. Boulenouar¹, T. Kajiume², L. Yuge^1,3. ¹Graduate School of Health Sciences, ²Graduate School of Biomedical Sciences, 3Space Bio-Laboratories Y. K., Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.

   A 3D-clinostat is a multi-directional gravity device, by controlled rotation of two axes, and makes 10^-3 G average over time. Bone marrow-derived cells (BMCs) are reported to differentiate into cells of neural lineages as well as mesenchymal cells in a media (neural differentiation medium). Our previous reports showed that culture of BMCs under the simulated microgravity may inhibit differentiation into these various types of cells. Therefore, we investigated the effect of simulated microgravity on differentiation of mouse BMCs, focusing on neural lineage. BMCs were isolated from BALB/cBy mice and harvested in 1G condition. Subjects were divided into two groups, cultured in 3D-clinostat (group CL) and 1G condition (group C) under the neural differentiation medium for 7 days. Group CL cells were transferred to 1G condition and kept under the neural induction for further 7 days or transplanted in mice brain. The cells were examined for morphology, expression of pluripotency marker (oct-4), and neural marker (neurofilament). Mice brains were removed at 3 weeks after transplantation and examined. Differentiation of the cells into neural lineage was inhibited in Group CL; cells extending processes and expressing neural marker were less found than group C. Furthermore, they expressed significantly pluripotency marker. And then, transferred to 1G condition, cells extending processes and expressing neural marker were found which indicate that differentiation proceeds. Group CL cells survived in mice brains after transplantation. In conclusion, we demonstrated that mouse BMCs maintained multipotency in culture in simulated microgravity by 3D-clinostat. Establishing cell therapy needs a mean of maintaining multipotency in donor cells for future use. This study suggests that simulated microgravity could be a candidate for that.