Heparin-binding epidermal-growth-factor-like growth factor gene expression is induced by scrape-wounding epithelial cell monolayers: involvement of mitogen-activated protein kinase cascades.
Peptide growth factors can promote the cell migration and proliferation that is needed to repair epithelia after mechanical or chemical injury. We report here that scrape-wounding rat intestinal epithelial (RIE-1) cell monolayers caused a rapid increase in levels of heparin-binding epidermal-growth-factor-like growth factor (HB-EGF) mRNA, with a maximal response at approx. 1 h. Hybridization in situ showed that transcript induction occurred primarily in cells at or near wound borders. The increase in HB-EGF mRNA was preceded by activation of the p42 mitogen-activated protein kinase (MAPK) in the wounded cell cultures. Moreover, the induction of HB-EGF mRNA was blocked by PD098059 and U0126, inhibitors that prevent the activation of p42/p44 MAPKs and extracellular signal-regulated protein kinase 5 (ERK5). Both p42 MAPK activation and HB-EGF mRNA induction were inhibited by genistein, indicating a requirement for an upstream tyrosine kinase activity. In contrast, neither response was affected by inhibition of phosphoinositide 3-kinase activity, down-regulation of protein kinase C, or disruption of the actin cytoskeleton with cytochalasin B. We conclude that scrape-wounding epithelial cell monolayers induces HB-EGF mRNA expression by a mechanism that most probably requires p42/p44 MAPK activation, although we cannot exclude a role for ERK5. Our results suggest a physiological role for locally synthesized HB-EGF in promoting epithelial repair after injury.
Ellis
P D
PD
The Babraham Institute, Babraham, Cambridge CB2 4AT, U.K.
Hadfield
K M
KM
Pascall
J C
JC
Brown
K D
KD
D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000235:genetics*; D004847:Epithelial Cells / Q000201:enzymology / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014947:Wounds and Injuries / Q000235:genetics*
D004791:Enzyme Inhibitors; D004815:Epidermal Growth Factor; D005419:Flavonoids; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D012333:RNA, Messenger; C587885:Hbegf protein, rat; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one