Impaired Expression of Prostaglandin E(2) (PGE(2)) Synthesis and Degradation Enzymes during Differentiation of Immortalized Urothelial Cells from Patients with Interstitial Cystitis/Painful Bladder Syndrome

PURPOSE: The differentiated superficial cells of the urothelium restrict urine flow into the bladder wall. We have demonstrated that urothelial cells isolated from bladders of patients with interstitial cystitis/painful bladder syndrome (IC/PBS) fail to release PGE(2) in response to tryptase. This study examines the expression of PGE(2) synthesis and degradation enzymes in urothelial cells during differentiation. MATERIALS AND METHODS: We measured immunoprotein expression of cyclooxygenase-2 (COX-2), prostaglandin E(2) synthase (PGES) and 15-hydroxyprostaglandin dehydrogenase (PGDH) in human urothelial cells and in immortalized urothelial cells isolated from the bladders of IC/PBS patients or normal subjects during stratification and differentiation produced by increased calcium and fetal bovine serum (Ca/FBS) in the culture medium for 1, 3 and 7 days. RESULTS: PGES immunoprotein expression increased during differentiation in normal and IC/PBS urothelial cells. COX-2 expression also increased in cells from normal patients following differentiation. Remarkably, no COX-2 expression was detectable in urothelial cells isolated from 3 out of 4 IC/PBS patients. PGDH immunoprotein expression decreased in normal cells after 1 and 3 days of Ca/FBS addition, but returned to normal after 7 days. PGDH expression was unchanged during differentiation at 1 and 3 days, but was more than 2-fold higher at 7 days compared to day 0 in the IC/PBS cells. Urothelial cells isolated from IC/PBS patients demonstrated no PGE(2) release in response to tryptase under any of the experimental conditions studied. CONCLUSIONS: Taken together, our results indicate that PGE(2) release is compromised during stratification and differentiation in IC/PBS urothelium and may contribute to impaired barrier function.