AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meanin...AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meaning of this system in the adult human gut is unknown. We investigated the Eph/ephrin mRNA expression in the intestinal epithelium of healthy controls and patients with inflammatory bowel disease (IBD). METHODS: mRNA expression profiles of all Eph/ephrin family members in normal small intestine and colon were established by real-time RT-PCR. In addition, differential expression in IBD was investigated by cDNA array technology, and validated by both real-time RT-PCR and immunohistochemistry. Potential effects of enhanced EphB/ephrin-B signaling were analyzed in an in vitro IEC-6 cell scratch wound model. RESULTS: Human adult intestinal mucosa exhibits a complex pattern of Eph receptors and ephrins. Beside the known prominent co-expression of EphA2 and ephrinAl, we found abundantly co-expressed EphB2 and ephrin-B1/2. Interestingly, cDNA array data, validated by real-time PCR and immunohistochemistry, showed upregulation of ephrin-B2 in both perilesional and lesional intestinal epithelial cells of IBD patients, suggesting a role in epithelial homeostasis. Stimulation of ephrin-B signaling in ephrin- B1/2 expressing rat IEC-6-cells with recombinant EphB1-Fc resulted in a significant dose-dependent acceleration of wound closure. Furthermore, fluorescence microscopy showed that EphB1-Fc induced coordinated migration of wound edge cells is associated with enhanced formation of lamellipodial protrusions into the wound, increased actin stress fiber assembly and production of laminin at the wound edge. CONCLUSION: EphB/ephrin-B signaling might represent a novel protective mechanism that promotes intestinal epithelial wound healing, with potential impact on epithelial restitution in IBD.展开更多
AIM： Eph receptors and ephrin ligands play a pivotal role in development and tissue maintenance. Since previous data have indicated an involvement of ephrin-B2 in epithelial healing, we investigated the gene expressi...AIM： Eph receptors and ephrin ligands play a pivotal role in development and tissue maintenance. Since previous data have indicated an involvement of ephrin-B2 in epithelial healing, we investigated the gene expression and downstream signaling pathways induced by ephrin-B mediated cell-cell signaling in intestinal epithelial cells. METHODS： Upon stimulation of ephrin-B pathways in IEC-6 cells with recombinant rat EphB1-Fc, gene expression was analyzed by Affymetrix rat genome 230 high density arrays at different time points. Differentially expressed genes were confirmed by real-time RT-PCR. In addition, MAP kinase pathways and focal adhesion kinase （FAK） activation downstream of ephrin-B were investigated by immunoblotting and fluorescence microscopy. RESULTS： Stimulation of the ephrin-B reverse signaling pathway in IEC-6 cells induces predominant expression of genes known to be involved into wound healing/cell migration, antiapoptotic pathways, host defense and inflammation. Cox-2, c-Fos, Egr-1, Egr-2, and MCP-1 were found among the most significantly regulated genes. Furthermore, we show that the expression of repair- related genes is also accompanied by activation of the ERKI/2 MAP kinase pathway and FAK, two key regulators of epithelial restitution. CONCLUSION： Stimulation of the ephrin-B reverse signaling pathway induces a phenotype characterized by upregulation of repair-related genes, which may partially be mediated by ERK1/2 pathways.展开更多
基金Supported by the Gennan Research Society (DFG-SFB 585/A8) and the Dr. Heinz Maurer Grant KFB 1.7
文摘AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meaning of this system in the adult human gut is unknown. We investigated the Eph/ephrin mRNA expression in the intestinal epithelium of healthy controls and patients with inflammatory bowel disease (IBD). METHODS: mRNA expression profiles of all Eph/ephrin family members in normal small intestine and colon were established by real-time RT-PCR. In addition, differential expression in IBD was investigated by cDNA array technology, and validated by both real-time RT-PCR and immunohistochemistry. Potential effects of enhanced EphB/ephrin-B signaling were analyzed in an in vitro IEC-6 cell scratch wound model. RESULTS: Human adult intestinal mucosa exhibits a complex pattern of Eph receptors and ephrins. Beside the known prominent co-expression of EphA2 and ephrinAl, we found abundantly co-expressed EphB2 and ephrin-B1/2. Interestingly, cDNA array data, validated by real-time PCR and immunohistochemistry, showed upregulation of ephrin-B2 in both perilesional and lesional intestinal epithelial cells of IBD patients, suggesting a role in epithelial homeostasis. Stimulation of ephrin-B signaling in ephrin- B1/2 expressing rat IEC-6-cells with recombinant EphB1-Fc resulted in a significant dose-dependent acceleration of wound closure. Furthermore, fluorescence microscopy showed that EphB1-Fc induced coordinated migration of wound edge cells is associated with enhanced formation of lamellipodial protrusions into the wound, increased actin stress fiber assembly and production of laminin at the wound edge. CONCLUSION: EphB/ephrin-B signaling might represent a novel protective mechanism that promotes intestinal epithelial wound healing, with potential impact on epithelial restitution in IBD.
基金Supported by the German Research Society (DFG - SFB 585/A8) and the Dr. Heinz Maurer Grant KFB 1.7
文摘AIM： Eph receptors and ephrin ligands play a pivotal role in development and tissue maintenance. Since previous data have indicated an involvement of ephrin-B2 in epithelial healing, we investigated the gene expression and downstream signaling pathways induced by ephrin-B mediated cell-cell signaling in intestinal epithelial cells. METHODS： Upon stimulation of ephrin-B pathways in IEC-6 cells with recombinant rat EphB1-Fc, gene expression was analyzed by Affymetrix rat genome 230 high density arrays at different time points. Differentially expressed genes were confirmed by real-time RT-PCR. In addition, MAP kinase pathways and focal adhesion kinase （FAK） activation downstream of ephrin-B were investigated by immunoblotting and fluorescence microscopy. RESULTS： Stimulation of the ephrin-B reverse signaling pathway in IEC-6 cells induces predominant expression of genes known to be involved into wound healing/cell migration, antiapoptotic pathways, host defense and inflammation. Cox-2, c-Fos, Egr-1, Egr-2, and MCP-1 were found among the most significantly regulated genes. Furthermore, we show that the expression of repair- related genes is also accompanied by activation of the ERKI/2 MAP kinase pathway and FAK, two key regulators of epithelial restitution. CONCLUSION： Stimulation of the ephrin-B reverse signaling pathway induces a phenotype characterized by upregulation of repair-related genes, which may partially be mediated by ERK1/2 pathways.
