Prostanoid receptor gene expression profile in human trabecular meshwork: A quantitative real-time PCR approach

PURPOSE. To assess the expression pattern of prostanoid receptor-encoding g enes in trabecular meshwork (TM) of human donor eyes. METHODS. Disposed human donor eyes (n = 10) were obtained from the Cornea B ank, Amsterdam. The TM was dissected from the scleral tissue and homogenize d in lysis buffer, and total RNA was isolated. The RNA was converted into c DNA and used as a template for noncompetitive quantitative real-time polyme rase chain reaction (PCR) using green fluorescent dye to quantify the accum ulation of double-stranded PCR product. Specific primers for four housekeep ing genes and DP, EP1, EP2, EP3, EP4, FP, IP, and TP receptor-encoding tran scripts were developed and tested for their efficiency. RESULTS. The characterized expression profile was highly reproducible in al l samples, with the EP, receptor-encoding transcript in the highest abundan ce, followed by FP, TP, IP, and EP4 at levels that were approximately 10 to 15 times lower than that of the EP2 subtype. DP and EP, were at the lowest levels, which were, on average, 45 times and 228 times lower than EP2, res pectively. CONCLUSIONS. These data show that all prostanoid receptors are expressed at different levels in human TM tissue. Because the gene expression of the EP , receptor is, on average, 15 times more abundant than that of the EP, rece ptor, it may be expected that the increase in flow and cAMP levels in respo nse to the activation of the EP receptors by application of prostaglandin E -1 (PGE(1)), is primarily mediated by the EP, receptor. These data should b e considered when designing prostanoid receptor mimetics intended to enhanc e the aqueous humor outflow through the TM and Schlemm's canal.