Purchase this article with an account.
C. C. Luna, G. Li, P. B. Liton, P. Gonzalez, D. L. Epstein; Cyclic Mechanical Stress-Induced Release of ATP Leads to Increased Mobilization of Arachidonic Acid in Trabecular Meshwork Cells. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4872.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We have previously demonstrated that cyclic mechanical stress (CMS) leads to ATP release in trabecular meshwork (TM) cells. Here we investigate the mechanisms that mediate the release of ATP induced by CMS and the role of ATP in the mobilization of arachidonic acid (AA) and prostaglandin secretion.
Porcine TM cells were cultured on flexible bottom plates and subjected to cyclic mechanical stress (20% stretching, 1 cycle per second). Extracellular ATP was measured with and without transport inhibitors (Piceatannol; Monensin; NEM; MβCD and Orthovanadate) and detected using a luciferin-luciferase bioluminescent assay. ATP vesicles were visualized using the fluorescent dye quinacrine. Arachidonic acid radioactive labeled (AA 1-14C) was measured using the Personal Molecular Imager FX. AA release was measured with and without ATP, ATP inhibitors (Suramin and Apyrase), and ATP/interleukins (IL1, IL1β, IL6 and IL8). Prostaglandin E2 (PGE2) was measured using a competitive binding ELISA assay.
The inhibitor of vesicle fusion NEM significantly decreased the release of ATP induced by CMS. CMS induced the release of AA (31% increase, p<0.05) and its metabolic product PGE2 (from 250 to 348 pg/ml p<0.05). The mobilization of AA induced by CMS was partially inhibited by the P2 antagonist Suramin and by the ATP inhibitor Apyrase, and could be mimicked by addition of extracellular ATP. Interleukins (IL1, IL1β, and IL8) significantly increased the basal level of AA (32%, 91%, and 111%, respectively p<0.05) IL1 showed a synergistic effect with ATP in the release of AA.
Our results indicate that the release of ATP induced by CMS in TM cells is primarily mediated through vesicular exocytosis and leads to increased mobilization of AA. Some of the most important products of AA metabolism include prostaglandins, which are hypothesized to increase aqueous humor outflow facility. Therefore, CMS in the TM may result in the release of intraocular pressure lowering molecules mediated by the initial release of ATP.
This PDF is available to Subscribers Only