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Abstract #47006 Published in IGR 13-3
S1P receptor regulation of sphingosine-1-phosphate effects on conventional outflow physiology
Sumida GM; Stamer WDAmerican Journal of Physiology and Cell Physiology 2011; 300: 1164-1171
Elevated intraocular pressure is the main risk factor in primary open-angle glaucoma, involving an increased resistance to aqueous humor outflow in the juxtacanalicular region of the conventional outflow pathway which includes the trabecular meshwork (TM) and the inner wall of Schlemm's canal (SC). Previously, sphingosine-1-phosphate (S1P) was shown to decrease outflow facility in porcine and human eyes, thus increasing outflow resistance and intraocular pressure. Owing to S1P's known effect of increasing barrier function in endothelial cells and the robust expression of the S1P receptor on the inner wall of SC, we hypothesized that S1P receptor activation promotes junction formation and decreases outflow facility. The effects of subtype-specific S1P receptor compounds were tested in human and porcine whole-eye perfusions and human primary cultures of SC and TM cells to determine the receptor responsible for S1P effects on outflow resistance. The S1P-specific agonist SEW2871 failed to both mimic S1P effects in paired human eye perfusions, as well as increase myosin light chain (MLC) phosphorylation in cell culture, a prominent outcome in S1P-treated SC and TM cells. In contrast, the S1P antagonist JTE-013, but not the S1P or S1P, antagonists, blocked the S1P-promoted increase in MLC phosphorylation. Moreover, JTE-013 prevented S1P-induced decrease in outflow facility in perfused human eyes (P < 0.05, n = 6 pairs). Similarly, porcine eyes perfused with JTE-013 + S1P did not differ from eyes with JTE-013 alone (P = 0.53, n = 3). These results demonstrate that S1P , and not S1P or S1P, receptor activation increases conventional outflow resistance and is a potential target to regulate intraocular pressure.
G.M. Sumida. Dept. of Ophthalmology and Vision Science, University of Arizona, 655 North Alvernon Way, Tucson, AZ 85711, USA.
Classification:
2.6.2.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.6 Aqueous humor dynamics > 2.6.2 Outflow)
3.6 Cellular biology (Part of: 3 Laboratory methods)
3.8 Pharmacology (Part of: 3 Laboratory methods)
