Zhang Chen-Ou, Wang Jian-Ying, Koch Kristopher R, Keay Susan
Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.
J Urol. 2005 Dec;174(6):2382-7. doi: 10.1097/01.ju.0000180417.11976.99.
Previous reports have suggested that the bladder epithelial barrier may be compromised in interstitial cystitis (IC). Antiproliferative factor (APF) is a small glycoprotein made specifically by bladder epithelial cells in patients with IC that induces changes in expression of certain epithelial cell proteins and profoundly inhibits cell growth. Therefore, we confirmed the increased permeability and decreased tight junction formation of bladder epithelial cell monolayers grown from biopsies in patients with IC compared to cells from normal controls. We then determined the effect of APF on the permeability of normal bladder epithelial cell monolayers and the expression of tight junction proteins.
Permeability was determined by measuring the C-mannitol and H-inulin flux between cells in confluent monolayers on Transwell culture plates (Corning, Corning, New York). Tight junction formation was assessed by immunofluorescence microscopy and the expression of specific proteins was determined by Western blot.
APF treatment caused significant increases in the paracellular permeability of normal bladder epithelial cell monolayers and the attenuation of tight junctions compared to mock APF, similar to changes seen in IC cells. APF treatment also decreased expression of the tight junction proteins zonula occludens-1 and occludin.
Because of its apparent effects on bladder epithelial cell tight junctions and paracellular permeability in vitro, APF may contribute to the leakiness of the bladder epithelial barrier seen in IC.
既往报道提示间质性膀胱炎（IC）患者膀胱上皮屏障可能受损。抗增殖因子（APF）是IC患者膀胱上皮细胞特异性产生的一种小糖蛋白，可诱导某些上皮细胞蛋白表达发生变化，并显著抑制细胞生长。因此，我们证实与正常对照细胞相比，IC患者活检组织来源的膀胱上皮细胞单层的通透性增加，紧密连接形成减少。然后我们确定了APF对正常膀胱上皮细胞单层通透性及紧密连接蛋白表达的影响。
通过测量Transwell培养板（康宁公司，纽约州康宁）上汇合单层细胞间的C-甘露醇和H-菊粉通量来测定通透性。通过免疫荧光显微镜评估紧密连接的形成，并通过蛋白质印迹法测定特定蛋白的表达。
与模拟APF处理相比，APF处理导致正常膀胱上皮细胞单层的细胞旁通透性显著增加，紧密连接减弱，这与IC细胞中的变化相似。APF处理还降低了紧密连接蛋白闭合蛋白-1和闭合蛋白的表达。
由于APF在体外对膀胱上皮细胞紧密连接和细胞旁通透性有明显影响，它可能导致IC患者膀胱上皮屏障的渗漏。
