Uroplakin III-delta 4 as a new molecular marker for interstitial cystitis

间质性膀胱炎（IC）是一种慢性膀胱疾病，在美国大约有100万人患有此病，其中90%是女性。IC的特征是尿频、尿急、膀胱不适或膀胱疼痛，没有任何可识别的原因，如细菌感染。由于缺乏可靠客观的诊断测试，IC仍然是基于症状和排除标准的诊断。哺乳动物尿路上皮的顶端表面覆盖着许多坚硬的斑块，这些斑块有助于形成渗透性屏障。eurplakins (UPs) Ia、Ib、II和III通过形成异源二聚体对（UPIa/ UPII和UPIb/ UPIII）组成这些斑块。UPIII-delta 4（UP3d4）是UPIII的一个剪接变体，可以通过缺少外显子4与UPIII区分。我们从膀胱输尿管反流患者膀胱黏膜样本cDNA文库中克隆了人UP3d4的完整cDNA片段。我们研究了包括UP3d4在内的更多UPs在IC患者膀胱粘膜中的表达，其中一个主要发现是UP3d4基因在IC样品中显著上调。更令人惊讶的是，UP3d4的上调在非溃疡型IC膀胱样本中被特异性观察到。本课题下一步将研究UP3d4蛋白在IC患者膀胱尿路上皮细胞中的表达情况。为此，我们用重组DNA技术制备了纯化的UP3d4蛋白的小鼠单克隆抗体。在46例IC患者中可检测到UP3d4蛋白表达，而27例患者因上皮脱落而未检测到UP3d4蛋白表达。46例样本中29例（63%）UP3d4免疫组化阳性。非溃疡型的阳性率为80%(20/ 25)，溃疡型的阳性率为43%(9/ 21)(p=0。014)。非ic膀胱粘膜未检出UP3d4。UP3d4染色阳性患者比阴性患者年轻（平均年龄：51岁）。5比62。0, p = 0。029)。24%(8/ 33) IC患者尿沉渣细胞中检测到UP3d4 mRNA表达；非溃疡型占18%(3/ 17)，溃疡型占31%（5/ 16）。综上所述，UP3d4蛋白在IC，特别是非溃疡型IC的尿路上皮中有较高的表达，UP3d4 mRNA在尿沉淀细胞中检测是可行的。UP3d4在IC发病机制和诊断中的潜在作用有待进一步探讨

Interstitial cystitis(IC) is a chronic bladder disorder affecting approximately one million people in the United States, of whom some 90% are women. IC is characterized by urinary frequency, urinary urgency, bladder discomfort or bladder pain in the absence of any identifiable cause, such as bacterial infection. Due to lacking in a reliably objective diagnostic test, IC remains a diagnosis based on symptoms and exclusion criteria.The apical surface of mammalian urothelium is covered by numerous rigid-appearing plaques that contribute to the permeability barrier. Uroplakins(UPs) Ia, Ib, II, and III consist of these plaques by forming heterodimer pairs(UPIa/ UPII and UPIb/ UPIII). UPIII-delta 4(UP3d4) is a splicing variant of UPIII that can be distinguished from UPIII by lacking exon 4. The whole cDNA fragment for human UP3d4 was molecularly cloned by us from a cDNA library constructed from bladder mucosa samples of a patient with vesicoureteral reflux. We investigated gene expression pr … More ofile of UPs including UP3d4 in bladder mucosa of patients with IC. One of the major findings of the study was that UP3d4 gene was significantly up-regulated in IC samples. What was more striking was that up-regulation of UP3d4 was specifically observed in non-ulcerative type IC bladder samples.The next step of this study project is to investigate protein expression of UP3d4 in bladder urothelial cells of IC patients. For this purpose, we have raised murine monoclonal antibodies against purified UP3d4 protein which was produced by the recombinant DNA technique. Protein expression of UP3d4 was evaluable in 46 IC patients while 27 were not due to epithelial exfoliation. UP3d4 was immunohistochemically positive in 29 of 46 samples(63%). The positive rate was 80%(20/ 25) in non-ulcer type and 43%(9/ 21) in ulcer type IC(p=0. 014). UP3d4 was not detected in any of non-IC bladder mucosa. Patients with positive UP3d4 staining was younger than those with negative staining(mean age : 51. 5 vs 62. 0, p=0. 029). UP3d4 mRNA expression was identified in urine sediment cells from 24%(8/ 33) IC patients ; 18%(3/ 17) in non-ulcer type and 31%(5/ 16) ulcer type.In conclusion, a high UP3d4 protein expression was demonstrated in urothelium of IC, especially non-ulcer type IC. Detection of UP3d4 mRNA was feasible for urine sediment cells. Further exploration is warranted to investigate the potential role of UP3d4 in pathogenesis and diagnosis of IC. Less