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1From the Schepens Eye Research Institute and 3Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts; the 2Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan; and the 4Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
PURPOSE. To compare activation of the p42/p44 mitogen-activated protein kinase (MAPK) by cholinergic agonists and epidermal growth factor (EGF) in cultured human and rat goblet cells.
METHODS. Conjunctiva was removed from either humans during ocular surgery or male SpragueDawley rats and cultured in RPMI medium. These cells were incubated with the cholinergic agonist carbachol (10-4 M) or EGF (10-8 M) for various times. Before stimulation, cells were incubated with the EGF receptor (EGFR) inhibitor, AG1478 (10-7 M) or the muscarinic M3 receptor inhibitor, 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine hydrochloride (4-DAMP; 10-5 M) for 10 minutes. Proteins were analyzed by Western blot analysis, using antibodies specific to phosphorylated (activated) p42/44-MAPK or total p42-MAPK. Immunoreactive bands were quantified, and data were expressed as percentage of increase over basal.
RESULTS. Carbachol (10-4 M) increased MAPK activity in human and rat cultured goblet cells in a time-dependent manner, increasing pMAPK with a maximum at 10 minutes. EGF (10-8 M) activated MAPK in human and rat goblet cells in a time-dependent manner with a maximum at 5 minutes. Carbachol- and EGF-induced activation of pMAPK was completely inhibited by AG1478 in cultured conjunctival goblet cells from both species. Carbachol-induced MAPK activity was also completely inhibited by 4-DAMP in both species.
CONCLUSIONS. In human and rat cultured conjunctival goblet cells, cholinergic agonists and EGF activate MAPK with a similar time dependency, this activation is receptor mediated, and cholinergic agonists transactivate the EGF receptor. Thus, rat cultured conjunctival goblet cells can be used as a model to study human conjunctival goblet cells.
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M. A. Shatos, J. Gu, R. R. Hodges, K. Lashkari, and D. A. Dartt ERK/p44p42 Mitogen-Activated Protein Kinase Mediates EGF-Stimulated Proliferation of Conjunctival Goblet Cells in Culture Invest. Ophthalmol. Vis. Sci., August 1, 2008; 49(8): 3351 - 3359. [Abstract] [Full Text] [PDF] |
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