| Co-Investigator(Kenkyū-buntansha) |
MINAMOTO Yoshiki Ajinomoto Co., Central Institute, Principal Researcher, 中央研究所, 主任研究員
OBATA Kunio National Institute of Physiological Sciences, Division of Neurochemistry, Profes, 生理学研究所, 教授 (60013976)
FURUYAMA Fujiya Nagoya City University Medical School, Department of Physiology, Instructor, 医学部, 助手 (00080101)
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| Research Abstract |
1. Fetal or neonatal mesencephalic (MS) cells, striatal (STR) cells and adrenal (AD) cells were transfected with SV40T/TS gene by culturing on the confluent 2 cells or culturing in the conditioned medium of 2 cells that have retroviral particles containing SV40T/TS.
2. Transfected cells grew better when EGF, FGF or conditioned medium of striatal cells were added in the culture medium.
3. After the growing period for 4 weeks in the standard or enriched medium, the transfected cells were cultured in the medium that contains G418 and eight G418-resistant cells were selected (MS-1, 2, 3 ; STR-1, 2 ; AD-1, 2, 3).
4. They grew under the temperature of 33。C and stopped growing under 39。C, thus they had thermosensitive character. The doubling time was approximately 4 weeks.
5. Only MS-1 and AD-1 were immunoreactive for tyrosine hydroxylase (TH). MS-2, 3 and STR-1, 2 were immunoreactive for both neurofilament and GFAP.
6. After growing in vitro, MS-1 and AD-1 were transplanted in the striatum of an animal model of Parkinson's disease, and STR-1, 2 were transplanted in the striatum of an animal model of brain ischemia. Each cells survived in the host brain for two weeks. However, after 4 weeks they became unhealthy and finally disappeared. Thus, they could not survive for a long perid that enables the functional restoration.
The reason why the grafted cells can not survive for a long period in the host brain is not clear yet. Various micro-environmental factors modulate the survival of the grafted cells. The characteristic of thermosensitivity might be a reason for that the cells cannot survive for a long period in the brain.
Thus, it is an urgent problem to find an endogenous promoter that enables the expression of transfected genes for a long period.
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