Analysis of expression and function of vacuolar-type H^+-ATPase at bladder

包括人在内的哺乳动物膀胱浅表细胞的管腔细胞质膜中存在液泡型H^+- atp酶；它们分泌质子使膀胱中的尿液酸化。为了研究它们的表达过程，我们建立了小鼠膀胱浅表细胞再生的实验模型。在该模型中，使用V-ATPase蛋白脂基因cDNA进行Northern blot杂交检测，V-ATPase mRNA的表达水平在胰蛋白酶处理浅表细胞去角质3小时后显著升高。另一方面，使用三种不同的细胞组分（富浅表细胞组分、富中间和富基底细胞组分和全细胞）进行western blotting，发现V-ATPase蛋白表达水平几乎相同。这些结果表明，在膀胱浅表细胞从中间细胞向浅表细胞分化的过程中，存在于细胞膜系统的v - atp酶进入腔质膜。我们还研究了v - atp酶在建立抗感染粘膜屏障和血尿屏障中的作用。

Vacuolar-type H^+-ATPases were present in luminal cytoplasmic membrane of bladder superficial cells in mammals including human ; which secrete protons to acidify the urine in the bladder. In order to study their expression process, we have developed an experimental model for regeneration of superficial cells of mouse bladder. In this model, the expression level of V-ATPase mRNA,which was measured by Northern blot hybridization using cDNA of V-ATPase proteolipid gene, increased significantly 3 hours after exfoliation of superficial cells by trypsin treatment. On the other hand, western blotting using three different cells fractions, superficial cells rich fraction, intermediate and basal cells rich fraction, and whole cells, revealed almost same levels of V-ATPase protein expression. These results suggested that V-ATPases present in endomembrane systems moved into luminal cytoplasmic membrane of bladder superficial cells during cell differentiation from intermediate to superficial cells. We also examined the role of V-ATPase in establishing mucosal barrier against infection as well as blood-urine barrier.