Abstract
Purpose: :
To determine the expression patterns in normal and glaucomatous human trabecular meshwork of two proline–rich proteins, Small Proline–Rich Protein–3 (SPRR–3) and Proline–Rich Protein–4 (PRP–4), which were recently identified in glaucomatous human trabecular meshwork by mass spectroscopy.
Methods: :
Normal human anterior chamber angle samples, as well as samples from patients with POAG have been collected. Normal samples were from corneoscleral rims from cornea donors for penetrating keratoplasty. POAG samples were obtained from excised tissue at the time of trabeculectomy procedures. Rabbit anti–peptide antibodies against SPRR–3 and PRP–4 were generated for immunohistochemistry and western blot analysis. Oligonucleotide primers were made for quantitative real–time polymerase chain reaction (PCR) analysis of SPRR–3 and PRP–4 messenger RNA.
Results: :
SPRR–3 and PRP–4 proteins were detected by immunohistochemistry in both normal and glaucomatous trabecular meshwork. Protein expression was detected throughout the trabecular meshwork, including the region adjacent to Schlemm's canal. Staining for the proteins was more intense in glaucomatous trabecular meshwork, suggesting higher levels of protein expression. Quantitative western and PCR analyses are in progress.
Conclusions: :
The human trabecular meshwork expresses two proline–rich proteins, SPRR–3 and PRP–4. Expression levels of these proteins are higher in glaucomatous tissue, consistent with our previous proteomic analysis. The function of these proteins in the trabecular meshwork is unknown and little is known about their biological functions in general. Correlation of higher protein expression in glaucomatous tissue suggests a possible role of these proteins in disease pathogenesis.
Keywords: trabecular meshwork • immunohistochemistry • gene/expression