胃粘膜上皮細胞の初代培養系を用いた増殖と分化の研究

Gastric fundic glands have a complex organization of several types of epithelial cells, including pit cells, parietal cells, neck cells, chief cells, and a variety of enteroendocrine cells. These functionally active cells come from multipotent stem cells that are found in the isthmus, and filiation and kinetics of these cells have been intensively studied in experimental animals. Transgenic mice have been introduced to study the mechanisms of cell lineage-specific and differentiation-dependent patterns of gene expression in the gastric units.
Primary cultures of gastric epithelial cells from rat, dog, rabbit, and guinea pig have been used to study interactions between distinct growth factors and gastric epithelial cells, and several growth factors, including epidermal growth factor (EGF). transforming growth factor-α, hepatocyte growth factor, insulin, and insulin-like growth factor 1, have been shown to stimulate proliferation of gastric epithelial cells. These primary cultures usually requires the presence of a high concentration of fetal calf serum, and cultured cells rapidly formed a monolayer within 2-3 days. A majority of the cells (90%) was identified as pit cells. We developed a complete serum-free culture of guinea pig gastric epithelial cells. The cells maintained in our culture conditions did not exhibit mitotic activity, and a great majority of the cells was in a pre-pit cell stage. EGF stimulated cell growth and then maturation into pit cells, suggesting that this culture system may be a excellent model to study the processes of maturation of a pit cell lineage.
Recently, gastric surface mucous cell lines (GSMO cells) from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene were established. A normal gastric epithelial cell line from rat gastric mucosa (RGM 1 cells) was also established. These cell lines may be useful for studying the proliferation and differentiation of a pit cell lineage.