Miyazaki Y, Shinomura Y, Tsutsui S, Zushi S, Higashimoto Y, Kanayama S, Higashiyama S, Taniguchi N, Matsuzawa Y
Department of Internal Medicine and Molecular Science, Graduate School of Medicine, Osaka University, Osaka, Japan. miyazaki@imed2,med.osaka-u.ac.jp
Gastroenterology. 1999 Jan;116(1):78-89. doi: 10.1016/s0016-5085(99)70231-3.
BACKGROUND & AIMS: Parietal cells express heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF). However, it is unknown whether HB-EGF mediates the trophic action of gastrin. The purpose of this study was to determine whether gastrin modulates the expression of HB-EGF, which mediates the proliferative effects of gastrin on gastric epithelial cells.
RGM1 cells, a rat gastric epithelial cell line, were transfected with a human gastrin receptor complementary DNA. Gastrin induction of messenger RNAs (mRNAs) for EGF-related polypeptides was assayed by Northern blotting. Processing of cell surface-associated proHB-EGF and secretion of HB-EGF were determined by flow cytometry and Western blotting, respectively. Tyrosine phosphorylation of the EGF receptor was assayed by immunoprecipitation and Western blotting with an antiphosphotyrosine antibody. Cell growth was evaluated by [3H]thymidine incorporation.
Gastrin induced expression of HB-EGF mRNA, processing of proHB-EGF, release of HB-EGF into the medium, and tyrosine phosphorylation of the EGF receptor. The growth-stimulatory effects of gastrin were partly inhibited by anti-rat HB-EGF serum and completely blocked by AG1478, an EGF receptor-specific tyrphostin.
The findings suggest that HB-EGF at least partially mediates the proliferative effects of gastrin on gastric epithelial cells.
壁细胞表达肝素结合表皮生长因子（EGF）样生长因子（HB-EGF）。然而，HB-EGF是否介导胃泌素的营养作用尚不清楚。本研究的目的是确定胃泌素是否调节HB-EGF的表达，而HB-EGF介导胃泌素对胃上皮细胞的增殖作用。
用人类胃泌素受体互补DNA转染大鼠胃上皮细胞系RGM1细胞。通过Northern印迹法检测胃泌素对EGF相关多肽信使核糖核酸（mRNA）的诱导作用。分别通过流式细胞术和蛋白质印迹法测定细胞表面相关前体HB-EGF的加工过程和HB-EGF的分泌。通过免疫沉淀和用抗磷酸酪氨酸抗体进行蛋白质印迹法检测EGF受体的酪氨酸磷酸化。通过[3H]胸苷掺入法评估细胞生长。
胃泌素诱导HB-EGF mRNA的表达、前体HB-EGF的加工、HB-EGF释放到培养基中以及EGF受体的酪氨酸磷酸化。胃泌素的生长刺激作用部分被抗大鼠HB-EGF血清抑制，被EGF受体特异性酪氨酸激酶抑制剂AG1478完全阻断。
这些发现表明，HB-EGF至少部分介导胃泌素对胃上皮细胞的增殖作用。
