Differentiation associated changes in gene expression profiles for interstitial cystitis and control urothelial cells

Purpose: Evaluate gene expression profiles after inducing differentiation in cultured interstitial cystitis (IC) and control urothelial cells. Materials and Methods: Bladder biopsies were taken from IC patients and controls (women having surgery for stress incontinence). Primary cultures were grown in Keratinocyte Growth Medium with supplements. To induce differentiation, in some plates the medium was changed to DMEM-F12 with supplements. RNA was analyzed with Affymetrix chips. Three nonulcer IC patients were compared with three controls. Results: After inducing differentiation, 302 genes with a described function were altered at least 3-fold with p <0.01 in both IC and control cells. Functions of the162 upregulated genes included cell adhesion (e.g. claudins, occludin, cingulin); urothelial differentiation, retinoic acid pathway and keratinocyte differentiation (e.g. skin cornified envelope components). The 140 downregulated genes included genes associated with basal urothelium (e.g. p63, integrins ?4, ?5 and ?6, basonuclin 1 and extracellular matrix components), vimentin, metallothioneins and members of the Wnt and Notch pathways. Comparing IC vs. control cells after differentiation, only seven genes with a described function were altered at least 3-fold with p <0.01. PI3, SERPINB4, CYP2C8, EFEMP2 and SEPP1 were decreased in IC; AKR1C2 and MKNK1 were increased in IC. Conclusions: Differentiation-associated changes occurred in both IC and control cells. Comparing IC vs. control revealed very few differences. This study may have included IC patients with minimal urothelial deficiency and/or selected the cells that were most robust in culture. Also, the abnormal urothelium in IC may be due to post-translational changes and/or the bladder environment.

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Erickson DR, Schwarze SR, Dixon JK, Clark CJ, Hersh MA