PMID- 17140565
OWN - NLM
STAT- MEDLINE
DCOM- 20070220
LR  - 20181113
IS  - 0014-4835 (Print)
IS  - 0014-4835 (Linking)
VI  - 84
IP  - 2
DP  - 2007 Feb
TI  - Fate of hypertonicity-stressed corneal epithelial cells depends on differential 
      MAPK activation and p38MAPK/Na-K-2Cl cotransporter1 interaction.
PG  - 361-72
AB  - The capacity of the corneal epithelium to adapt to hypertonic challenge is 
      dependent on the ability of the cells to upregulate the expression and activity 
      of cell membrane-associated Na-K-2Cl cotransporter1 (NKCC1). Yet, the signaling 
      pathways that control this response during hypertonic stress are still unclear. 
      We studied stress-induced changes in proliferation and survival capacity of 
      SV40-immortalized human (HCEC) and rabbit (RCEC) corneal epithelial cells as a 
      function of (i) the magnitude of the hypertonic challenge, (ii) differential 
      changes in activation of mitogen-activated protein kinase (MAPK), and (iii) the 
      extent of p38MAPK interaction with NKCC1. Cells were incubated in hypertonic (up 
      to 600 mOsm) media for varying time periods up to 24 h. Phosphorylated forms of 
      p44/42, p38, and stress-activated protein kinase/c-Jun N-terminal kinase 
      (SAPK/JNK) MAPK were immunoprecipitated from cell lysates, and the amount of each 
      activated NKCC1-associated MAPK was evaluated by Western blot/ECL assay. DNA 
      integrity was assessed by electrophoresis in a 2% agarose gel. Cell survival and 
      proliferation were evaluated based on three criteria: protein content, cell 
      count, and the MTT assay. Exposure to media of 325-350 mOsm increased 
      proliferation of HCEC up to 75%, whereas this response was limited to <16% in 
      RCEC. At higher osmolarities, cell proliferation decreased in both species. 
      SAPK/JNK activity increased 150-fold in HCEC and <10-fold in RCEC, while DNA 
      fragmentation occurred only in HCEC. Compared to HCEC, the better RCEC survival 
      rate was associated with higher p38MAPK activity and near complete restoration of 
      p44/42MAPK activity after the first 30 min. In both cell lines, the amount of 
      phospho-NKCC1 that coimmunoprecipitated with phospho-p38MAPK was proportional to 
      the magnitudes of their respective activation levels. However, no such 
      associations occurred between amounts of phosphorylated p44/42MAPK or SAPK/JNK 
      and phospho-NKCC1. Under isotonic conditions, with bumetanide-induced inhibition 
      of RCEC and HCEC NKCC1 activities, p44/42MAPK activity declined by 40 and 60%, 
      respectively. Such declines led to proportional decreases in cell proliferation. 
      Survival of hypertonicity-stressed corneal epithelial cells depends both on 
      p38MAPK activation capacity and the ability of p38MAPK to stimulate NKCC1 
      activity through protein-protein interaction. The level of NKCC1 activation 
      affects the extent of cell volume recovery and, in turn, epithelial survival 
      capacity.
FAU - Capo-Aponte, Jose E
AU  - Capo-Aponte JE
AD  - Department of Biological Sciences, State University of New York, State College of 
      Optometry, 33West 42nd Street, New York, NY 10036, USA.
FAU - Wang, Zheng
AU  - Wang Z
FAU - Bildin, Victor N
AU  - Bildin VN
FAU - Pokorny, Kathryn S
AU  - Pokorny KS
FAU - Reinach, Peter S
AU  - Reinach PS
LA  - eng
GR  - R01 EY004795/EY/NEI NIH HHS/United States
GR  - R56 EY004795/EY/NEI NIH HHS/United States
GR  - EY04795/EY/NEI NIH HHS/United States
GR  - R01 EY004795-23/EY/NEI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20061130
PL  - England
TA  - Exp Eye Res
JT  - Experimental eye research
JID - 0370707
RN  - 0 (Eye Proteins)
RN  - 0 (Hypertonic Solutions)
RN  - 0 (SLC12A2 protein, human)
RN  - 0 (Sodium-Potassium-Chloride Symporters)
RN  - 0 (Solute Carrier Family 12, Member 2)
RN  - EC 2.7.11.24 (p38 Mitogen-Activated Protein Kinases)
RN  - EC 2.7.12.2 (Mitogen-Activated Protein Kinase Kinases)
SB  - IM
MH  - Cell Death/drug effects/physiology
MH  - Cell Line, Transformed
MH  - Cell Proliferation/drug effects
MH  - Cell Transformation, Viral
MH  - Cells, Cultured
MH  - Enzyme Activation
MH  - Epithelium, Corneal/*cytology/drug effects/metabolism
MH  - Eye Proteins/*metabolism
MH  - Humans
MH  - Hypertonic Solutions/pharmacology
MH  - Mitogen-Activated Protein Kinase Kinases/*metabolism
MH  - Protein Binding
MH  - Simian virus 40
MH  - Sodium-Potassium-Chloride Symporters/*metabolism
MH  - Solute Carrier Family 12, Member 2
MH  - p38 Mitogen-Activated Protein Kinases/*metabolism
PMC - PMC1815383
MID - NIHMS16779
EDAT- 2006/12/05 09:00
MHDA- 2007/02/21 09:00
PMCR- 2008/02/01
CRDT- 2006/12/05 09:00
PHST- 2006/07/18 00:00 [received]
PHST- 2006/09/17 00:00 [revised]
PHST- 2006/10/10 00:00 [accepted]
PHST- 2006/12/05 09:00 [pubmed]
PHST- 2007/02/21 09:00 [medline]
PHST- 2006/12/05 09:00 [entrez]
PHST- 2008/02/01 00:00 [pmc-release]
AID - S0014-4835(06)00418-0 [pii]
AID - 10.1016/j.exer.2006.10.011 [doi]
PST - ppublish
SO  - Exp Eye Res. 2007 Feb;84(2):361-72. doi: 10.1016/j.exer.2006.10.011. Epub 2006 
      Nov 30.