Abstract
Purpose:
Hyperosmolar stress is central to the pathogenesis of dry eye disease. Ocular surface epithelial cells actively participate in fluid and electrolyte transport. Herein, we investigate the effects of hyperosmolar stress on the conjunctival expression of sodium-hydrogen exchanger (NHE) 8.
Methods:
NHE8 expression was assessed in human conjunctival and gastrointestinal epithelial cells. Human conjunctival epithelial cells were cultured in normal osmolar media and then subcultured in hyperosmolar media (350 and 400mOsM). Quantitative real-time polymerase chain reaction and western blot were used to measure NHE8 expression at mRNA and protein levels, respectively.
Results:
NHE8 was abundantly expressed in both human conjunctival and gastrointestinal epithelial cells at mRNA and protein levels. Hyperosmolar stress significantly decreased the mRNA expression of NHE8 with the greatest effect observed at 400mOsM. Similarly, hyperosmolar stress consistently decreased the protein expression of NHE8 with the greatest effect observed at 400mOsM.
Conclusions:
Hyperosmolar stress downregulated the expression of NHE8 in human conjunctival epithelial cells, potentially implicating NHE8 in the pathogenesis of dry eye disease.
Keywords: 474 conjunctiva •
570 ion transporters