title: Dependence of corneal epithelial cell proliferation on modulation of interactions between ERK1/2 and NKCC1.
abstract: Epidermal growth factor (EGF) receptor stimulation or protein kinase C (PKC) activation enhances corneal epithelial cell proliferation. This response is needed to maintain corneal transparency and vision. We clarify here in human corneal epithelial cells (HCEC) the cause and effect relationships between ERK1/2 and NKCC1 phosphorylation induced by EGF receptor or PKC activation. Furthermore, the roles are evaluated of NF-κB and ERK1/2 in mediating negative feedback control of ERK1/2 and NKCC1 phosphorylation through modulating DUSP1 and DUSP6 expression levels. Intracellular Ca(2+) rises induced by EGF elicited NKCC1 phosphorylation through ERK1/2 activation. Bumetanide suppressed EGF-induced NKCC1 phosphorylation, transient cell swelling and cell proliferation. This cause and effect relationship is similar to that induced by PKC stimulation. NKCC1 activation occurred through time-dependent increases in protein-protein interaction between ERK1/2 and NKCC1, which were proportional to EGF concentration. DUSP6 upregulation obviated EGF and PKC-induced NKCC1 phosphorylation. NF-κB inhibition by PDTC prolonged ERK1/2 activation through GSK-3 inactivation leading to declines in DUSP1 expression levels. These results show that EGF receptor and PKC activation induce increases in HCEC proliferation through ERK1/2 interaction with NKCC1. This response is modulated by changes in DUSP1- and DUSP6-mediated negative feedback control of ERK1/2-induced NKCC1 phosphorylation.
authors.affiliation: Department of Biological Sciences, State University of New York, State College of Optometry, New York, NY 10036, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Victor N
authors.initials: VN
authors.lastname: Bildin
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: José E
authors.initials: JE
authors.lastname: Capó-Aponte
authors.forename: Yuanquan
authors.initials: Y
authors.lastname: Yang
authors.forename: Peter S
authors.initials: PS
authors.lastname: Reinach
mesh_terms: D002034:Bumetanide / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology*; D054638:Dual Specificity Phosphatase 1 / Q000378:metabolism; D054642:Dual Specificity Phosphatase 6 / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000494:pharmacology; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2
chemical_list: D016328:NF-kappa B; C578877:SLC12A2 protein, human; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; D002034:Bumetanide; D066246:ErbB Receptors; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D038362:Glycogen Synthase Kinase 3; C517019:DUSP1 protein, human; C517035:DUSP6 protein, human; D054638:Dual Specificity Phosphatase 1; D054642:Dual Specificity Phosphatase 6; D002118:Calcium