The exogenous control of transfected c-fos gene expression and angiogenesis in cells implanted into the rat brain.
Previously, we established a stable transfectant, Nf-1, from normal rat kidney (NRK) fibroblasts transfected with a human metallothionein II A (hMT-IIA) promoter/human genomic c-fos fusion gene to produce c-Fos protein. Since the hMT-IIA promoter can be activated by heavy metals, the level of human c-fos gene expression can be increased by addition of heavy metals to the culture medium of Nf-1 cells and the anchorage-independent growth of Nf-1 in soft agar is markedly enhanced in the presence of transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF). In this study, we found that the hMT-IIA promoter can be activated by zinc, resulting in the elevation of fused c-fos gene expression in Nf-1 cells. We transplanted NRK and Nf-1 cells into the striatum of the rat brain and investigated whether expression of the human c-fos gene could be modified in the brain by exogenous zinc. After 8 weeks, we found that the Nf-1 cells could survive in the rat brain without any immunosuppression and grafts of Nf-1 induced angiogenesis when zinc was administered. Such implants enhanced the expression of c-fos mRNA by zinc. These results indicated that the transplanted cells continued expressing the c-fos transgene when the rats were given drinking water containing zinc, resulting in the promotion of cell growth and of neovascularization. This study will present a useful animal model of gene therapy by control of transgene expression in the brain.
Asakuno
K
K
Department of Neurosurgery, Oita Medical University, Japan.
Isono
M
M
Wakabayashi
Y
Y
Mori
T
T
Hori
S
S
Kohno
K
K
Kuwano
M
M
D000818:Animals; D016380:Brain Tissue Transplantation; D002452:Cell Count / Q000187:drug effects; D015870:Gene Expression / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D014162:Transfection / Q000235:genetics*; D015032:Zinc / Q000494:pharmacology
D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D015032:Zinc