Rapid mitogen-activated protein kinase activation by transforming growth factor α in wounded rat intestinal epithelial cells
Rapid mitogen-activated protein kinase activation by transforming growth factor α in wounded rat intestinal epithelial cells
复制标题
DOI：
10.1016/s0016-5085(98)70583-9
复制
发表时间：
1998-04-01
期刊：
影响因子：
29.4
通讯作者：
Podolsky, DK
中科院分区：
文献类型：
--
作者：
Göke, M;Kanai, M;Podolsky, DK
背景和目标：为了定义肠上皮损伤后启动加热的信号传导事件，使用体外模型在创伤后评估丝裂原活化蛋白激酶（MAPK）途径的活化。研究方法：从非转化的肠上皮细胞（IEC-6）的损伤单层分离的蛋白质进行了分析酪氨酸磷酸化和MAPK表达的Western印迹。细胞外信号调节激酶（ERK）1，ERK 2，和Raf-1的活动进行了评估，通过免疫复合物激酶测定。结果：损伤后5分钟，包括ERK 1在内的几种蛋白的酪氨酸磷酸化显著增加。另一种MAPK，c-Jun-1-末端蛋白激酶（JNK），也在创伤后被激活。条件培养基从受伤，但不是完整的IEC-6单层导致ERK 1，ERK 2，和Raf-1激酶的活性增加。与来自完整IEC-6培养物的条件培养基相比，伤口条件培养基刺激亚融合IEC-6细胞的增殖，并且含有比融合IEC-6培养物的上清液更高量的转化生长因子（TGF）-α。ERK 1和ERK 2的活化被中和性抗TGF-α抗体部分抑制。结论：肠上皮细胞的损伤导致Raf-1、ERK 1、ERK 2和JNK 1 MAPK的激活以及随后的体外细胞增殖。ERK 1和ERK 2的激活部分由TGF-α介导。
Background & Aims: To define signaling events initiating heating after intestinal epithelial injury, activation of mitogen-activated protein kinase (MAPK) pathways was assessed after wounding using an in vitro model. Methods: Proteins isolated from wounded monolayers of nontransformed intestinal epithelial cells (IEC-6) were analyzed for tyrosine phosphorylation and MAPK expression by Western blot. Extracellular signal-regulated kinase (ERK) 1, ERK2, and Raf-1 activities were assessed by immune complex kinase assays. Results: Tyrosine phosphorylation of several proteins including ERK1 was substantially increased 5 minutes after injury. Another MAPK, c-Jun-1-terminal protein kinase (JNK), was also activated after wounding. Conditioned medium from wounded but not intact IEC-6 monolayers resulted in increased activity of ERK1, ERK2, and Raf-1 kinase. Wound-conditioned medium stimulated proliferation of subconfluent IEC-6 cells compared with conditioned medium from intact IEC-6 cultures and contained higher amounts of transforming growth factor (TGF)-alpha than supernatants of confluent IEC-6 cultures. Activation of ERK1 and ERK2 was partially inhibited by neutralizing anti-TGF-alpha. Conclusions: Wounding of intestinal epithelial cells results in activation of Raf-1, ERK1, ERK2, and JNK1 MAPKs and subsequent cell proliferation in vitro. Activation of ERK1 and ERK2 is mediated in part by TGF-alpha.