PMID- 10549641 OWN - NLM STAT- MEDLINE DCOM- 19991108 LR - 20101118 IS - 0146-0404 (Print) IS - 0146-0404 (Linking) VI - 40 IP - 12 DP - 1999 Nov TI - Expression of phosphatidylinositol 3-kinase during EGF-stimulated wound repair in rabbit corneal epithelium. PG - 2819-26 AB - PURPOSE: To investigate the effect of epidermal growth factor (EGF) on the induction of phosphatidylinositol 3-kinase (PI 3- kinase) gene expression during rabbit corneal epithelial wound repair. METHODS: Epithelial wounds (6 mm in size) were created in rabbit corneas and EGF (2 microg) applied every 8 hours to one eye, and the other eye served as a control. The wound repair was monitored by staining the tissue with fluorescein followed by photography. The wound area was quantified with a computer program. At different time intervals, the rabbits were killed and the corneal epithelium used for estimation of PI 3-kinase activity, western blot analysis, or reverse transcription-polymerase chain reaction (RT-PCR). For in situ hybridization, the whole corneas were sectioned and the sections processed with PI 3-kinase mRNA probes. RESULTS: In the untreated eye, the epithelial wound progressively healed in a time-dependent manner, with 75% of the wound closed at 48 hours post wounding. Application of EGF to the corneal epithelium further stimulated wound repair at all time intervals, and the wound was completely closed at 48 hours. Analysis of PI 3-kinase showed a time-dependent increase in its enzyme activity that was maximally increased at 36 hours, the time when the wound was nearly closed. Western blot analysis revealed increased amounts of PI 3- kinase protein during the course of wound repair. Analysis of RT-PCR products from epithelial tissues, taken at different times during wound repair, showed increased PI 3-kinase expression that was maximum at 48 hours post wounding. A visible increase in PI 3-kinase gene expression was also detected by in situ hybridization during the course of the wound repair. This expression was increased maximally by EGF at 48 hours post wounding. CONCLUSIONS: The results indicate a temporal correlation between increased activation and expression of PI 3- kinase and the epithelial wound repair. Topical application of EGF further stimulates the activity and expression of PI 3- kinase. It is suggested that PI 3- kinase and its products may play a role in EGF-induced cell proliferation during corneal epithelial wound repair. FAU - Zhang, Y AU - Zhang Y AD - Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912, USA. FAU - Liou, G I AU - Liou GI FAU - Gulati, A K AU - Gulati AK FAU - Akhtar, R A AU - Akhtar RA LA - eng GR - EY 05738/EY/NEI NIH HHS/United States PT - Comparative Study PT - Journal Article PT - Research Support, U.S. Gov't, P.H.S. PL - United States TA - Invest Ophthalmol Vis Sci JT - Investigative ophthalmology & visual science JID - 7703701 RN - 0 (RNA, Messenger) RN - 62229-50-9 (Epidermal Growth Factor) RN - EC 2.7.1.- (Phosphatidylinositol 3-Kinases) SB - IM MH - Animals MH - Base Sequence MH - Blotting, Western MH - Cattle MH - Epidermal Growth Factor/*pharmacology MH - Epithelium, Corneal/*drug effects/enzymology/injuries/pathology MH - Fluorophotometry MH - Gene Expression MH - Humans MH - In Situ Hybridization MH - Mice MH - Molecular Sequence Data MH - Phosphatidylinositol 3-Kinases/*biosynthesis/*genetics MH - RNA, Messenger/metabolism MH - Rabbits MH - Rats MH - Reverse Transcriptase Polymerase Chain Reaction MH - Sequence Homology, Nucleic Acid MH - Time Factors MH - Wound Healing/*drug effects EDAT- 1999/11/05 00:00 MHDA- 1999/11/05 00:01 CRDT- 1999/11/05 00:00 PHST- 1999/11/05 00:00 [pubmed] PHST- 1999/11/05 00:01 [medline] PHST- 1999/11/05 00:00 [entrez] PST - ppublish SO - Invest Ophthalmol Vis Sci. 1999 Nov;40(12):2819-26.