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-ĸB and ERK1/2 in mediating negative feedback control of ERK1/2 and NKCC1 phosphorylation through modulating DUSP1 and DUSP6 expression levels. Intracellular Ca²⁺ 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-ĸB 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.

Aldosterone modulates thiazide-sensitive sodium chloride cotransporter abundance via DUSP6-mediated ERK1/2 signaling pathway

“…Although the SPAK/OSR1 signaling pathway plays a critical role in regulating NCC activity (19), the MAPK signaling pathway also plays an important role in the regulation of SLC12 cation chloride cotransporter family members such as NCC and NKCC (7,21,36,37). Our results are the first to demonstrate that aldosterone modulates NCC through a DUSP6/ERK1/2 signaling pathway that does not require intact SPAK/OSR1 signaling pathway.…”

Functional TRPV1 expression in human corneal fibroblasts

“…Ca 2+ transients mediate receptor induced mitogen activated protein kinase phosphorylation (MAPK) (Berridge et al, 2000) in numerous different tissues as well as HCEC (Wang et al, 2011b). As TRPV1 activation by CAP in HCEC elicited global MAPK phosphorylation (i.e.…”

Bumetanide-induced NKCC1 inhibition attenuates oxygen–glucose deprivation-induced decrease in proliferative activity and cell cycle progression arrest in cultured OPCs via p-38 MAPKs

“…Accumulating studies have demonstrated that NKCC1 participates in cell volume maintenance, apoptosis, migration, proliferation, and toxicity of ions, and pharmacological inhibition of NKCC1 decreases ischemia-induced cell swelling, brain blood barrier breakdown and neurotoxicity (Chen et al, 2005;Garzon-Muvdi et al, 2012;Jayakumar and Norenberg, 2010;Jayakumar et al, 2011;Kahle et al, 2008Kahle et al, , 2009Kidokoro et al, 2014;Wang et al, 2011). Nevertheless, its role in OPCs proliferation and cell cycle progression remains poorly understood.…”

“…However, NKCC1 inhibition may also have a negative role in cell cycle regulation in corneal epithelial cells (Wang et al, 2011). We speculate that spatial and temporal regulation of NKCC1 activity b r a i n r e s e a r c h 1 6 1 3 ( 2 0 1 5 ) 1 1 0 -1 1 9 will lead to differential regulation of growth-regulatory proteins in different cell types or under OGD.…”