Detection of prostaglandin EP1, EP2, and FP receptor subtypes in human sclera

PURPOSE. To examine the expression of five prostaglandin (PG) receptors, EP 1, EP2, EP3, EP4, and FP and their corresponding mRNA transcripts in human sclera and cultured human scleral fibroblasts (HSFs). METHODS. Primary cultures of HSFs were established from donor eyes. Also, s clera from human donor eyes was snap frozen and sectioned. Immunocytochemis try was performed on HSFs and tissue sections with subtype-specific antibod ies to the EP1, EP2, EP3, EP4, and FP receptors. The presence of mRNA for t he receptor subtypes was examined from total RNA obtained from, human scler a and confirmed with restriction digest analysis. RESULTS. Positive EP1 and FP receptor immunoreactivity was observed in fibr oblasts within the sections from human sclera. In primary cultures of HSFs, EP1 and FP labeling was observed over the entire cell surface. EP2 immunor eactivity within HSFs was mostly present in the juxtanuclear region. RT-PCR analysis of total RNA isolated from human sclera and HSFs confirmed the pr esence of EP1, EP2, and FP receptor subtypes. The identity of the polymeras e chain reaction products was confirmed by restriction enzyme analysis. No mRNA or immunoreactivity above basal levels was detected for the EP3 and EP 4 prostanoid receptor subtypes in tissue sections or primary cultures. CONCLUSIONS. The EP,, EP2, and FP receptor subtypes are present in HSFs, su ggesting that these cells may respond to endogenous PGs and their structura l analogues through interaction with these receptor subtypes.