Candidate genes involved in the defunctionalization and refunctionalization of the urinary bladder induced by bladder anuria and reperfusion.

AIMS: We develop a novel rabbit urinary diversion model of bladder defunctionalization due to bladder anuria followed by refunctionalization due to urine reperfusion to investigate the molecular biological background. To validate the results, we used reverse transcription-polymerase chain reaction (RT-PCR) to analyze human specimens from defunctionalized bladders in patients receiving dialysis before kidney transplantation. METHODS: Female rabbits were divided into three groups: control, defunctionalized, and refunctionalized. The bilateral ureters were anastomosed to vagina in the defunctionalized and refunctionalized groups at 0 weeks. In the refunctionalized group, the unilateral ureter was reanastomosed to the bladder at 8 weeks. RESULTS: The capacity and compliance of the rabbit bladder in the refunctionalized group were significantly lower than those in the control group at 8 weeks and higher than those in the defunctionalized group at 14 weeks. The significant downregulation of IGFBP2, UPK1B, and CST6 in the defunctionalized group compared with that in the control groups, and the significant downregulation of AGTR2 in the refunctionalized group compared with that in the defunctionalized group in the rabbit bladder-muscle DNA microarray were validated by RT-PCR. Human bladder muscle indicated significant downregulation of UPK1B and CST6 and significant downregulation of IGFBP2 in the defunctionalized group, which is consistent with both rabbit bladder-muscle DNA microarray and rabbit bladder RT-PCR results. CONCLUSIONS: The present study using novel model of bladder defunctionalization followed by refunctionalization indicated the consistent downregulation of UPK1B and CST6 in muscle and the consistent downregulation of IGFBP2 in mucosa in process of bladder defunctionalization, which was validated by human specimens.

The egg membrane microdomain-associated uroplakin III-Src system becomes functional during oocyte maturation and is required for bidirectional gamete signaling at fertilization in Xenopus laevis.

In Xenopus laevis, sperm-egg interaction promotes partial proteolysis and/or tyrosine phosphorylation of uroplakin III (UPIII) and the tyrosine kinase Src, which both localize to the cholesterol-enriched egg membrane microdomains (MDs). Here we show that sperm promote proteolysis and/or tyrosine phosphorylation of UPIII and Src in MDs isolated from ovulated and unfertilized eggs (UF-MDs). An antibody against the extracellular domain of UPIII interferes with these events. Inhibition of fertilization by anti-UPIII antibody is rescued by co-incubation with UF-MDs. This suggests that, like MDs in intact eggs, the isolated UF-MDs are capable of interacting with sperm, an interaction that does not interfere with normal fertilization but rather augments the ability of sperm to fertilize eggs pretreated with anti-UPIII antibody. This unexpected effect of UF-MDs on sperm requires UPIII function in UF-MDs and protein kinase activity in sperm. MDs isolated from progesterone-treated mature oocytes, but not ovarian immature oocytes, are similarly functional as UF-MDs. The anti-UPIII extracellular domain antibody binds more effectively to the surface of mature than immature ovarian oocytes. We propose that the structural and functional competency of the UPIII-Src signaling system in MDs is strictly regulated during oocyte maturation and subsequently in sperm-mediated egg activation and fertilization. The fertilization-related signaling properties seen in UF-MDs can be partially reconstituted in MDs of human embryonic kidney 293 cells (293-MDs) expressing UPIII, Src and uroplakin Ib. However, 293-MDs expressing a proteolysis-resistant mutant of UPIII are less functional, suggesting that the availability of UPIII to protease action is important for MD function.

Role of renal urothelium in the development and progression of kidney disease.

The clinical and financial impact of chronic kidney disease (CKD) is significant, while its progression and prognosis is variable and often poor. Studies using the megabladder (mgb -/- ) model of CKD show that renal urothelium plays a key role in modulating early injury responses following the development of congenital obstruction. The aim of this review is to examine the role that urothelium has in normal urinary tract development and pathogenesis. We discuss normal morphology of renal urothelium and then examine the role that uroplakins (Upks) play in its development. Histologic, biochemical, and molecular characterization of Upk1b RFP/RFP mice indicated Upk1b expression is essential for normal urinary tract development, apical plaque/asymmetric membrane unit (AUM) formation, and differentiation and functional integrity of the renal urothelium. Our studies provide the first evidence that Upk1b is directly associated with the development of congenital anomalies of the urinary tract (CAKUT), spontaneous age-dependent hydronephrosis, and dysplastic urothelia. These observations demonstrate the importance of proper urothelial differentiation in normal development and pathogenesis of the urinary tract and provide a unique working model to test the hypothesis that the complex etiology associated with CKD is dependent upon predetermined genetic susceptibilities that establish pathogenic thresholds for disease initiation and progression.

Uroplakin 1b is critical in urinary tract development and urothelial differentiation and homeostasis.

Proper development and maintenance of urothelium is critical to its function. Uroplakins are expressed in developing and mature urothelium where they establish plaques associated with the permeability barrier. Their precise functional role in development and disease is unknown. Here, we disrupted Upk1b in vivo where its loss resulted in urothelial plaque disruption in the bladder and kidney. Upk1b(RFP/RFP) bladder urothelium appeared dysplastic with expansion of the progenitor cell markers, Krt14 and Krt5, increased Shh expression, and loss of terminal differentiation markers Krt20 and uroplakins. Upk1b(RFP/RFP) renal urothelium became stratified with altered cellular composition. Upk1b(RFP/RFP) mice developed age-dependent progressive hydronephrosis. Interestingly, 16% of Upk1b(RFP/RFP) mice possessed unilateral duplex kidneys. Our study expands the role of uroplakins, mechanistically links plaque formation to urinary tract development and function, and provides a tantalizing connection between congenital anomalies of the kidney and urinary tract along with functional deficits observed in a variety of urinary tract diseases. Thus, kidney and bladder urothelium are regionally distinct and remain highly plastic, capable of expansion through tissue-specific progenitor populations. Furthermore, Upk1b plays a previously unknown role in early kidney development representing a novel genetic target for congenital anomalies of the kidney and urinary tract.

The predictive value of urinary UPIb mRNA levels in VUR and recurrent urinary tract infections.

BACKGROUND: Vesicoureteral reflux (VUR) is a risk factor for progressive kidney damage especially when it is accompanied by urinary tract infections (UTIs). Uroplakins (UPs) are integral proteins found in the structure of urothelium. In the present study, we evaluated the usefulness of urinary UPIb messenger ribonucleic acid (mRNA) levels as an early and noninvasive diagnostic tool for VUR and as an indicator for predisposition to UTI. METHODS: Urinary UPIb mRNA levels were determined in patients experiencing their first UTI episode (n = 28) or recurrent UTI (n = 31) as well as patients having UTI with VUR (n = 30). These results were compared to a control group (n = 26). RESULTS: The UPIb mRNA values among patients diagnosed with their first UTI were lower, but not statistically different, than those in the control group. The UPIb mRNA levels of patients with recurrent UTI and UTI with VUR were significantly lower than those observed in control individuals. CONCLUSION: Urine UPIb levels may be useful for predicting the risk of recurrent UTI in patients diagnosed with their first UTI and may also be considered as a noninvasive screening test for VUR.

Loss of Upk1a and Upk1b expression is linked to stage progression in urothelial carcinoma of the bladder.

BACKGROUND: Uroplakin-1a (Upk1a) and uroplakin-1b (Upk1b) have recently been identified as diagnostic markers for the distinction of urothelial carcinomas from other solid tumor entities. Both proteins play an important role in the stabilization and strengthening of epithelial cells that line the bladder. METHODS: To evaluate the prognostic role of uroplakin expression in urothelial carcinomas, more than 2700 urothelial neoplasms were analyzed in a tissue microarray format by immunohistochemistry. To further assess the diagnostic role of uroplakin immunohistochemistry, results were compared with preexisting GATA3 data. RESULT: The fraction of Upk1a/Upk1b positive cases decreased slightly from pTaG2 low-grade (88% positive for Upk1a/87% positive for Upk1b) and pTaG2 high-grade (92%/89%) to pTaG3 (83%/88%; p > 0.05) and was lower in muscle-invasive (pT2-4) carcinomas (42%/64%; p < 0.0001/p < 0.0001 for pTa vs. pT2-4). Within pT2-4 carcinomas, high expression of Upk1a and Upk1b was linked to nodal metastasis and lymphatic vessel infiltration (p < 0.05) but unrelated to patient outcome. There were significant associations between Upk1a, Upk1b and GATA3 immunostaining (p < 0.0001 each), but 11% of GATA3 negative cancers were Upk1a/b positive and 8% of Upk1a/b negative cancers were GATA3 positive. Absence of GATA3/Upk1a/b staining was significantly linked to poor patient survival in the subgroup of 126 pT4 carcinomas (p = 0.0004) but not in pT2 and pT3 cancers. CONCLUSIONS: In summary, the results of our study demonstrate that Upk1a and/or Upk1b immunohistochemistry can complement GATA3 for the distinction of urothelial carcinomas. Furthermore, a progressive loss of Upk1a/b expression during stage progression and a prognostic role of the combination GATA3/Upk1a/Upk1b in pT4 carcinomas is evident.

Local immune response in bladder pain syndrome/interstitial cystitis ESSIC type 3C.

INTRODUCTION AND HYPOTHESIS: Bladder pain syndrome/interstitial cystitis (BPS/IC) is identified based on subjective symptoms which lead to heterogeneous patient populations. Previous studies using gene expression arrays for BPS/IC with Hunner's lesions [European Society for the Study of Interstitial Cystitis (ESSIC) type 3C], a subtype of the condition discernible by cystoscopy, have revealed characteristic immune responses and urothelial abnormalities. This current study aimed to further characterize this subtype using a gene expression panel. We hypothesized that B-cell activation with high levels of urinary antibody concentration would be found. METHODS: Cold-cup bladder biopsies, catheterized urine and blood were collected from 15 BPS/IC ESSIC type 3C patients, 11 non-inflammatory overactive bladder (OAB) patients and eight healthy controls. Gene expression in biopsies was quantified by real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry was performed on bladder tissue and urinary immunoglobulins G and A were quantified by enzyme-linked immunosorbent assay. Statistical analyses included the Kruskal-Wallis test for non-parametric data and post hoc tests identified differences between groups. RESULTS: High expression of T- and B-cell markers (CTLA4, CD20, CD79A, IGH@), low expression of urothelial markers (KRT20, UPK1B, UPK3A), focal lymphoid aggregates in the submucosa and high immunoglobulin concentration in urine were found exclusively in BPS/IC ESSIC type 3C patients. Results for OAB were in intermediate ranges between the other two groups and UPK1B even reached significantly lower expression when compared to healthy controls. CONCLUSIONS: BPS/IC ESSIC type 3C is characterized by a local adaptive immune response with elevated urinary antibody concentrations. Quantification of urinary immunoglobulin levels could be used for a non-invasive diagnosis of BPS/IC ESSIC type 3C.

UPK1B promoted the invasion and stem cell characteristics of non-small cell lung cancer cells by modulating c-myc/Sox4 axis.

Non-small cell lung cancer (NSCLC) is a malignant tumor with extremely high mortality. Uroplakin1B (UPK1B) promotes the occurrence and development of multiple types of cancer by enhancing the expression of c-myc and Sox4. However, whether UPK1B can modulate the development of NSCLC by regulating c-myc/Sox4 axis is unclear. In this study, UPK1B was overexpressed or knocked down in the non-small cell lung cancer cells (NSCLCs) were. Next, the proliferation and invasion of those cells were detected with the EdU staining and transwell assays. Sphere formation assays was performed to examine the stem cell characteristics of those cells. Then, we overexpressed the Sox4 in UPK1B knockdown cells and determined the proliferation and invasion of those cells. Our results showed that UPK1B promoted the proliferation, invasion and stem cell characteristics of NSCLCs. In addition, UPK1B enhanced the expression of c-myc, Sox4 and stem cell associated proteins in those cells. Overexpression of Sox4 rescued the proliferation and invasion of NSCLCs, which were suppressed by the UPK1B knockdown. In summary, our study suggested that UPK1B enhanced the invasiveness and stem cell characteristics of NSCLCs by activating c-myc/UPK1B axis.

KRT13 and UPK1B for differential diagnosis between metastatic lung carcinoma from oral squamous cell carcinoma and lung squamous cell carcinoma.

Oral squamous cell carcinomas unusually show distant metastasis to the lung after primary treatment, which can be difficult to differentiate from primary squamous cell carcinoma of the lung. While the location and number of tumor nodules is helpful in diagnosing cases, differential diagnosis may be difficult even with histopathological examination. Therefore, we attempted to identify molecules that can facilitate accurate differential diagnosis. First, we performed a comprehensive gene expression analysis using microarray data for OSCC-LM and LSCC, and searched for genes showing significantly different expression levels. We then identified KRT13, UPK1B, and nuclear receptor subfamily 0, group B, member 1 (NR0B1) as genes that were significantly upregulated in LSCC and quantified the expression levels of these genes by real-time quantitative RT-PCR. The expression of KRT13 and UPK1B proteins were then examined by immunohistochemical staining. While OSCC-LM showed no KRT13 and UPK1B expression, some tumor cells of LSCC showed KRT13 and UPK1B expression in 10 of 12 cases (83.3%). All LSCC cases were positive for at least one of these markers. Thus, KRT13 and UPK1B might contribute in differentiating OSCC-LM from LSCC.

Production of human tetraspanin proteins in Escherichia coli.

Tetraspanins are found in multicellular eukaryotes and are generally thought to act as scaffolding proteins, localizing multiple proteins to a specific region of the cell membrane. Activities for tetraspanins have been identified in several fundamental processes such as motility, cell adhesion, proliferation and viral entry. Tetraspanins are also key players in cancer development and progression. However, structural and biochemical information on tetraspanins is decidely limited, due in no small part to the difficulties associated with expressing eukaryotic membrane proteins. In this study, we have used GFP fusions of a library of human tetraspanin proteins to identify growth conditions for expression in Escherichia coli. Three tetraspanin-GFP proteins could be produced at high enough levels to allow subsequent purification, paving the way for future structural and biochemical studies.

Large-scale human tissue analysis identifies Uroplakin 1b as a putative diagnostic marker in surgical pathology.

Uroplakin 1B (Upk1b) stabilizes epithelial cells lining the bladder lumen to prevent rupturing during bladder distension. Little is known about Upk1b expression in other normal and malignant tissues. To comprehensively evaluate the potential diagnostic and prognostic utility of Upk1b expression analysis, a tissue microarray containing 14,061 samples from 127 different tumor types and subtypes and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. Upk1b immunostaining was found in 61 (48%) different tumor types including 50 (39%) with at least one moderately positive and 39 tumor types (31%) with at least one strongly positive tumor. Highest positivity rates were found in urothelial neoplasms (58-95%), Brenner tumors of the ovary (92%), epithelioid mesothelioma (87%), serous carcinoma of the ovary (58%) and the endometrium (53%) as well as in squamous cell carcinoma of the head and neck (18-37%), lung (39%), and esophagus (26%). In urothelial carcinoma, low Upk1b expression was linked to high grade and invasive tumor growth (P < .0001 each) and nodal metastasis (P = .0006). Our data suggest diagnostic applications of Upk1b immunohistochemistry in panels for the distinction of malignant mesothelioma from adenocarcinoma of the lung, urothelial carcinoma from prostatic adenocarcinoma in the bladder, or pancreaticobiliary and gastroesophageal from colorectal adenocarcinoma.

Expression and localization of four uroplakins in urothelial preneoplastic lesions.

In superficial umbrella cells of normal urothelium, uroplakins (UPs) are assembled into urothelial plaques, which form fusiform vesicles (FVs) and microridges of the apical cell surface. Altered urothelial differentiation causes changes in the cell surface structure. Here, we investigated ultrastructural localization of UPIa, UPIb, UPII and UPIIIa in normal and cyclophosphamide-induced preneoplastic mouse urothelium. In normal urothelium, terminally differentiated umbrella cells expressed all four UPs, which were localized to the large urothelial plaques covering mature FVs and the apical plasma membrane. The preneoplastic urothelium contained two types of superficial cells with altered differentiation: (1) poorly differentiated cells with microvilli and small, round vesicles that were uroplakin-negative; no urothelial plaques were observed in these cells; (2) partially differentiated cells with ropy ridges contained uroplakin-positive immature fusiform vesicles and the apical plasma membrane. Freeze-fracturing showed small urothelial plaques in these cells. We concluded that in normal urothelium, all four UPs colocalize in urothelial plaques. However, in preneoplastic urothelium, the growth of the uroplakin plaques was hindered in the partially differentiated cells, leading to the formation of immature FVs and ropy ridges instead of mature FVs and microridges. Our study demonstrates that despite a lower level of expression, UPIa, UPIb, UPII and UPIIIa maintain their plaque association in urothelial preneoplastic lesions.

Structural basis for tetraspanin functions as revealed by the cryo-EM structure of uroplakin complexes at 6-A resolution.

Tetraspanin uroplakins (UPs) Ia and Ib, together with their single-spanning transmembrane protein partners UP II and IIIa, form a unique crystalline 2D array of 16-nm particles covering almost the entire urothelial surface. A 6 A-resolution cryo-EM structure of the UP particle revealed that the UP tetraspanins have a rod-shaped structure consisting of four closely packed transmembrane helices that extend into the extracellular loops, capped by a disulfide-stabilized head domain. The UP tetraspanins form the primary complexes with their partners through tight interactions of the transmembrane domains as well as the extracellular domains, so that the head domains of their tall partners can bridge each other at the top of the heterotetramer. The secondary interactions between the primary complexes and the tertiary interaction between the 16-nm particles contribute to the formation of the UP tetraspanin network. The rod-shaped tetraspanin structure allows it to serve as stable pilings in the lipid sea, ideal for docking partner proteins to form structural/signaling networks.

NAA10 promotes proliferation of renal cell carcinoma by upregulating UPK1B.

OBJECTIVE: The purpose of this study was to illustrate the role of NAA10 in aggravating the malignant progression of renal cell carcinoma (RCC) by upregulating UPK1B. PATIENTS AND METHODS: NAA10 levels in RCC tissues and paracancerous tissues were detected. Thereafter, the potential relationship between NAA10 level and clinical parameters of RCC patients was analyzed. After knockdown of NAA10, changes in proliferative potential of 786-O and Caki-1 cells were examined by cell counting kit-8 (CCK-8), colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Finally, the regulatory role of NAA10 in the downstream gene UPK1B and the involvement of UPK1B in the development of RCC were determined via rescue experiments. RESULTS: NAA10 was upregulated in RCC tissues than paracancerous tissues. Tumor staging was much worse in RCC patients expressing a higher level of NAA10. Knockdown of NAA10 inhibited proliferative potential and downregulated UPK1B in RCC cells. Besides, NAA10 level was identified to be positively linked to UPK1B level in RCC tissues. At last, overexpression of UPK1B was able to abolish the inhibitory effect of silenced NAA10 on RCC proliferation. CONCLUSIONS: NAA10 level is closely linked to tumor staging and poor prognosis in RCC patients. NAA10 aggravates the malignant progression of RCC by upregulating UPK1B and may be a specific biomarker in RCC.

The performance of the Xpert Bladder Cancer Monitor Test and voided urinary cytology in the follow-up of urinary bladder tumors.

BACKGROUND: Cystoscopy in complement with urinary cytology represents the gold standard for the follow-up of patients with urinary bladder tumours. Xpert Bladder Cancer Monitor Test (XBC) is a novel mRNA-based urine test for bladder cancer surveillance. The aim of the study was to evaluate the performance of the XBC and voided urinary cytology (VUC) in the follow-up of bladder tumours. PATIENTS AND METHODS: The XBC was performed on stabilized voided urine and VUC was performed on urine samples. The results were compared to cystoscopic findings and histopathological results after transurethral resection of the bladder lesion. RESULTS: For the prediction of malignant histopathological result sensitivity, the specificity and negative predictive value were 76.9%, 9 7.5% and 93.0% for the XBC and 38.4%, 9 7.5% and 83.3%, respectively for VUC. For the prediction of suspicious or positive cystoscopic finding sensitivity, the specificity and negative predictive value were 75.0%, 95.2%, and 93.0% respectively for the XBC and 41.7%, 97.6%, and 85.4% for VUC. The sensitivities for papilary urothelial neoplasms of low malignant potential (PUNLMP), low- and high-grade tumours were 0.0%, 66.7% an d 100.0% for the XBC and 0.0%, 66 .7% and 42.9%, respectively for VUC. CONCLUSIONS: The XBC showed significantly higher overall sensitivity and negative predictive value than VUC and could be used to increase the recommended follow-up cystoscopy time intervals. Complementing the XBC and voided urinary cytology does not improve performance in comparison to the XBC alone.

Ablation of uroplakin III gene results in small urothelial plaques, urothelial leakage, and vesicoureteral reflux.

Urothelium synthesizes a group of integral membrane proteins called uroplakins, which form two-dimensional crystals (urothelial plaques) covering >90% of the apical urothelial surface. We show that the ablation of the mouse uroplakin III (UPIII) gene leads to overexpression, defective glycosylation, and abnormal targeting of uroplakin Ib, the presumed partner of UPIII. The UPIII-depleted urothelium features small plaques, becomes leaky, and has enlarged ureteral orifices resulting in the back flow of urine, hydronephrosis, and altered renal function indicators. Thus, UPIII is an integral subunit of the urothelial plaque and contributes to the permeability barrier function of the urothelium, and UPIII deficiency can lead to global anomalies in the urinary tract. The ablation of a single urothelial-specific gene can therefore cause primary vesicoureteral reflux (VUR), a hereditary disease affecting approximately 1% of pregnancies and representing a leading cause of renal failure in infants. The fact that VUR caused by UPIII deletion seems distinct from that caused by the deletion of angiotensin receptor II gene suggests the existence of VUR subtypes. Mutations in multiple gene, including some that are urothelial specific, may therefore cause different subtypes of primary reflux. Studies of VUR in animal models caused by well-defined genetic defects should lead to improved molecular classification, prenatal diagnosis, and therapy of this important hereditary problem.

Uroplakin IIIb, a urothelial differentiation marker, dimerizes with uroplakin Ib as an early step of urothelial plaque assembly.

Urothelial plaques consist of four major uroplakins (Ia, Ib, II, and III) that form two-dimensional crystals covering the apical surface of urothelium, and provide unique opportunities for studying membrane protein assembly. Here, we describe a novel 35-kD urothelial plaque-associated glycoprotein that is closely related to uroplakin III: they have a similar overall type 1 transmembrane topology; their amino acid sequences are 34% identical; they share an extracellular juxtamembrane stretch of 19 amino acids; their exit from the ER requires their forming a heterodimer with uroplakin Ib, but not with any other uroplakins; and UPIII-knockout leads to p35 up-regulation, possibly as a compensatory mechanism. Interestingly, p35 contains a stretch of 80 amino acid residues homologous to a hypothetical human DNA mismatch repair enzyme-related protein. Human p35 gene is mapped to chromosome 7q11.23 near the telomeric duplicated region of Williams-Beuren syndrome, a developmental disorder affecting multiple organs including the urinary tract. These results indicate that p35 (uroplakin IIIb) is a urothelial differentiation product structurally and functionally related to uroplakin III, and that p35-UPIb interaction in the ER is an important early step in urothelial plaque assembly.

Uroplakins Ia and Ib, two major differentiation products of bladder epithelium, belong to a family of four transmembrane domain (4TM) proteins.

The mammalian bladder epithelium elaborates, as a terminal differentiation product, a specialized plasma membrane called asymmetric unit membrane (AUM) which is believed to play a role in strengthening and stabilizing the urothelial apical surface through its interactions with an underlying cytoskeleton. Previous studies indicate that the outer leaflet of AUM is composed of crystalline patches of 12-nm protein particles, and that bovine AUMs contain three major proteins: the 27- to 28-kD uroplakin I, the 15-kD uroplakin II and the 47-kD uroplakin III. As a step towards elucidating the AUM structure and function, we have cloned the cDNAs of bovine uroplakin I (UPI). Our results established the existence of two isoforms of bovine uroplakin I: a 27-kD uroplakin Ia and a 28-kD uroplakin Ib. These two glycoproteins are closely related with 39% identity in their amino acid sequences. Hydropathy plot revealed that both have four potential transmembrane domains (TMDs) with connecting loops of similar length. Proteolytic digestion of UPIa inserted in vitro into microsomal vesicles suggested that its two main hydrophilic loops are exposed to the luminal space, possibly involved in interacting with the luminal domains of other uroplakins to form the 12-nm protein particles. The larger loop connecting TMD3 and TMD4 of both UPIa and UPIb contains six highly conserved cysteine residues; at least one centrally located cysteine doublet in UPIa is involved in forming intramolecular disulfide bridges. The sequences of UPIa and UPIb (the latter is almost identical to a hypothetical, TGF beta-inducible, TI-1 protein of mink lung epithelial cells) are homologous to members of a recently described family all possessing four transmembrane domains (the "4TM family"); members of this family include many important leukocyte differentiation markers such as CD9, CD37, CD53, and CD63. The tissue-specific and differentiation-dependent expression as well as the naturally occurring crystalline state of uroplakin I molecules make them uniquely suitable, as prototype members of the 4TM family, for studying the structure and function of these integral membrane proteins.

Induction and evasion of host defenses by type 1-piliated uropathogenic Escherichia coli.

Virtually all uropathogenic strains of Escherichia coli encode filamentous surface adhesive organelles called type 1 pili. High-resolution electron microscopy of infected mouse bladders revealed that type 1 pilus tips interacted directly with the lumenal surface of the bladder, which is embedded with hexagonal arrays of integral membrane glycoproteins known as uroplakins. Attached pili were shortened and facilitated intimate contact of the bacteria with the uroplakin-coated host cells. Bacterial attachment resulted in exfoliation of host bladder epithelial cells as part of an innate host defense system. Exfoliation occurred through a rapid apoptosis-like mechanism involving caspase activation and host DNA fragmentation. Bacteria resisted clearance in the face of host defenses within the bladder by invading into the epithelium.

Prospective Validation of an mRNA-based Urine Test for Surveillance of Patients with Bladder Cancer.

BACKGROUND: A fast, noninvasive test with high sensitivity (SN) and a negative predictive value (NPV), which is able to detect recurrences in bladder cancer (BC) patients, is needed. A newly developed urine assay, Xpert Bladder Cancer Monitor (Xpert), measures five mRNA targets (ABL1, CRH, IGF2, UPK1B, and ANXA10) that are frequently overexpressed in BC. OBJECTIVE: To validate Xpert characteristics in patients previously diagnosed with non-muscle-invasive BC. DESIGN, SETTING, AND PARTICIPANTS: Voided precystoscopy urine samples were prospectively collected at 22 sites. Xpert, cytology, and UroVysion were performed. If cystoscopy was suspicious for BC, a histologic examination was performed. Additionally, technical validation was performed and specificity was determined in patients without a history or clinical evidence of BC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Test characteristics were calculated based on cystoscopy and histology results, and compared between Xpert, cytology, and UroVysion. RESULTS AND LIMITATIONS: Of the eligible patients, 239 with a history of BC had results for all assays. The mean age was 71 yr; 190 patients were male, 53 never smoked, and 64% had previous intravesical immunotherapy (35%) or chemotherapy (29%). Forty-three cases of recurrences occurred. Xpert had overall SN of 74% (95% confidence interval [CI]: 60-85) and 83% (95% CI: 64-93) for high-grade (HG) tumors. The NPV was 93% (95% CI: 89-96) overall and 98% (95% CI: 94-99) for HG tumors. Specificity was 80% (95% CI: 73-85). Xpert SN and NPV were superior to those of cytology and UroVysion. Specificity in non-BC individuals (n=508) was 95% (95% CI: 93-97). CONCLUSIONS: Xpert has an improved NPV compared with UroVysion and cytology in patients under follow-up for BC. It represents a promising tool for excluding BC in these patients, reducing the need for cystoscopy. PATIENT SUMMARY: Xpert is an easy-to-perform urine test with good performance compared with standard urine tests. It should help optimize the follow-up of recurrent bladder cancer patients.