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Zhao Liu, XIN CHEN, DING CHEN, Stephen C Pflugfelder, De-Quan Li; Osmolarity-dependently Protective Effects of Trehalose on Inflammatory Markers in Primary Human Corneal Epithelial Cells Exposed to Hyperosmotic Stress. Invest. Ophthalmol. Vis. Sci. 2017;58(8):492.
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© ARVO (1962-2015); The Authors (2016-present)
Hyperosmolarity has been recognized as a pro-inflammatory stress in the pathogenesis of dry eye disease. This study was to explore the protective effects of the disaccharide trehalose on expression and production of pro-inflammatory mediators in primary human corneal epithelial cells (HCECs) exposed to hyperosmotic stress.
Primary HCECs were established from fresh donor limbal tissue explants. The cultures in iso-osmolar medium (312 mOsM) were switched to hyperosmotic media (450 mOsM) by adding 70 mM NaCl, with or without prior incubation of different concentrations (0.1-5%) of trehalose, alone or in combination of another osmoprotectant, L-carnitine, for different times (4-24 hours). The mRNA expression by HCECs was determined by reverse transcription and quantitative real time PCR. The protein production in the conditioned media from cultures was evaluated by ELISA.
The expression of pro-inflammatory cytokines, TNF-α, IL-1β and IL-6, and chemokine IL-8 was significantly stimulated in HCECs exposed to hyperosmotic medium (450 mOsM). This stimulation was largely suppressed at both mRNA and protein levels by prior-treatment with trehalose at 0.5-1.5% while 1.0% showed the best effect. Higher concentrations (2.0-3.0%) of trehalose reduced the suppressive effects on these pro-inflammatory markers in a concentration-dependent manner, and 5% had no suppressive effect, or was associated with higher expression of these markers. This phenomenon was likely due to the higher osmolarity (500~570 mOsM) generated by 2.0-5.0% of trehalose in the HCEC hyperosmolarity model. Prior treatment with 1.0% trehalose in combination with L-carnitine at 10 mM significantly enhanced the inhibitory effects on these pro-inflammatory markers at mRNA and protein levels, causing 20-50% further down-regulation. Further investigations are going on to explore the differential molecular mechanisms initiated by trehalose and L-carnitine.
Our findings demonstrate that hyperosmotic stress stimulates the expression and production of proinflammatory mediators in HCECs. Trehalose functions as an osmoprotectant, producing an osmolarity-dependent suppression of inflammatory responses. L-carnitine further enhances the protective effects initiated by trehalose, suggesting that the 2 compounds may act by different mechanisms and have synergistic effects.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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