Cellular basis of urothelial squamous metaplasia: roles of lineage heterogeneity and cell replacement

Vitamin A-Enriched Diet Increases Urothelial Cell Proliferation by Upregulating Itga3 and Areg After Cyclophosphamide-Induced Injury in Mice

Vitamin A (VitA) is an essential nutrient, affecting many cell functions, such as proliferation, apoptosis, and differentiation, all of which are important for the regeneration of various tissues. In this study, we investigated the effects of a VitA-enriched diet on the regeneration of the urothelium of the urinary bladder in mice after cyclophosphamide (CP)-induced injury. Female mice were fed VitA-enriched and normal diet for 1 week before receiving an intraperitoneal injection of CP (150 mg/kg). Urinary bladders were removed 1 and 3 days after CP. On Day 1, RNA sequencing showed that VitA upregulated two Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways: the cell cycle and the PI3K-Akt pathway. This was confirmed by qPCR, which showed significantly increased expression of the Itga3 and Areg genes. In addition, the effect of VitA on the proliferation of urothelial cells was analyzed by immunohistochemistry of Ki-67, which confirmed an increased proliferation rate. No significant effects of the VitA-enriched diet were observed on the expression of apoptosis-related genes and on differentiation-related markers of superficial urothelial cells. Our results suggest that a VitA-enriched diet improves early urothelial regeneration after CP-induced injury by promoting cell proliferation.

The urothelial gene regulatory network: understanding biology to improve bladder cancer management

The urothelium is a stratified epithelium composed of basal cells, one or more layers of intermediate cells, and an upper layer of differentiated umbrella cells. Most bladder cancers (BLCA) are urothelial carcinomas. Loss of urothelial lineage fidelity results in altered differentiation, highlighted by the taxonomic classification into basal and luminal tumors. There is a need to better understand the urothelial transcriptional networks. To systematically identify transcription factors (TFs) relevant for urothelial identity, we defined highly expressed TFs in normal human bladder using RNA-Seq data and inferred their genomic binding using ATAC-Seq data. To focus on epithelial TFs, we analyzed RNA-Seq data from patient-derived organoids recapitulating features of basal/luminal tumors. We classified TFs as "luminal-enriched", "basal-enriched" or "common" according to expression in organoids. We validated our classification by differential gene expression analysis in Luminal Papillary vs. Basal/Squamous tumors. Genomic analyses revealed well-known TFs associated with luminal (e.g., PPARG, GATA3, FOXA1) and basal (e.g., TP63, TFAP2) phenotypes and novel candidates to play a role in urothelial differentiation or BLCA (e.g., MECOM, TBX3). We also identified TF families (e.g., KLFs, AP1, circadian clock, sex hormone receptors) for which there is suggestive evidence of their involvement in urothelial differentiation and/or BLCA. Genomic alterations in these TFs are associated with BLCA. We uncover a TF network involved in urothelial cell identity and BLCA. We identify novel candidate TFs involved in differentiation and cancer that provide opportunities for a better understanding of the underlying biology and therapeutic intervention.

Mechanotransduction in the urothelium: ATP signalling and mechanoreceptors

The urothelium, which covers the inner surface of the bladder, is continuously exposed to a complex physical environment where it is stimulated by, and responds to, a wide range of mechanical cues. Mechanically activated ion channels endow the urothelium with functioning in the conversion of mechanical stimuli into biochemical events that influence the surface of the urothelium itself as well as suburothelial tissues, including afferent nerve fibres, interstitial cells of Cajal and detrusor smooth muscle cells, to ensure normal urinary function during the cycle of filling and voiding. However, under prolonged and abnormal loading conditions, the urothelial sensory system can become maladaptive, leading to the development of bladder dysfunction. In this review, we summarize developments in the understanding of urothelial mechanotransduction from two perspectives: first, with regard to the functions of urothelial mechanotransduction, particularly stretch-mediated ATP signalling and the regulation of urothelial surface area; and secondly, with regard to the mechanoreceptors present in the urothelium, primarily transient receptor potential channels and mechanosensitive Piezo channels, and the potential pathophysiological role of these channels in the bladder. A more thorough understanding of urothelial mechanotransduction function may inspire the development of new therapeutic strategies for lower urinary tract diseases.

Combined Mek inhibition and Pparg activation Eradicates Muscle Invasive Bladder cancer in a Mouse Model of BBN-induced Carcinogenesis

Bladder cancers (BCs) can be divided into 2 major subgroups displaying distinct clinical behaviors and mutational profiles: basal/squamous (BASQ) tumors that tend to be muscle invasive, and luminal/papillary (LP) tumors that are exophytic and tend to be non-invasive. Pparg is a likely driver of LP BC and has been suggested to act as a tumor suppressor in BASQ tumors, where it is likely suppressed by MEK-dependent phosphorylation. Here we tested the effects of rosiglitazone, a Pparg agonist, in a mouse model of BBN-induced muscle invasive BC. Rosiglitazone activated Pparg signaling in suprabasal epithelial layers of tumors but not in basal-most layers containing highly proliferative invasive cells, reducing proliferation but not affecting tumor survival. Addition of trametinib, a MEK inhibitor, induced Pparg signaling throughout all tumor layers, and eradicated 91% of tumors within 7-days of treatment. The 2-drug combination also activated a luminal differentiation program, reversing squamous metaplasia in the urothelium of tumor-bearing mice. Paired ATAC-RNA-seq analysis revealed that tumor apoptosis was most likely linked to down-regulation of Bcl-2 and other pro-survival genes, while the shift from BASQ to luminal differentiation was associated with activation of the retinoic acid pathway and upregulation of Kdm6a, a lysine demethylase that facilitates retinoid-signaling. Our data suggest that rosiglitazone, trametinib, and retinoids, which are all FDA approved, may be clinically active in BASQ tumors in patients. That muscle invasive tumors are populated by basal and suprabasal cell types with different responsiveness to PPARG agonists will be an important consideration when designing new treatments.

Nanogold based protein localization enables subcellular visualization of cell junction protein by SBF-SEM

Recent advances in volume electron microscopy (vEM) allow unprecedented visualization of the electron-dense structures of cells, tissues and model organisms at nanometric resolution in three dimensions (3D). Light-based microscopy has been widely used for specific localization of proteins; however, it is restricted by the diffraction limit of light, and lacks the ability to identify underlying structures. Here, we describe a protocol for ultrastructural detection, in three dimensions, of a protein (Connexin 43) expressed in the intercalated disc region of adult murine heart. Our protocol does not rest on the expression of genetically encoded proteins and it overcomes hurdles related to pre-embedding and immunolabeling, such as the penetration of the label and the preservation of the tissue. The pre-embedding volumetric immuno-electron microscopy (pre-embedding vIEM) protocol presented here combines several practical strategies to balance sample fixation with antigen and ultrastructural preservation, and penetration of labeling with blocking of non-specific antigen binding sites. The small 1.4 nm gold along with surrounded silver used as a detection marker buried in the sample also serves as a functional conductive resin that significantly reduces the charging of samples. Our protocol also presents strategies for facilitating the successful cutting of the samples during serial block-face scanning electron microscopy (SBF-SEM) imaging. Our results suggest that the small gold-based pre-embedding vIEM is an ideal labeling method for molecular localization throughout the depth of the sample at subcellular compartments and membrane microdomains.

Single-cell and spatial mapping Identify cell types and signaling Networks in the human ureter

Tissue engineering offers a promising treatment strategy for ureteral strictures, but its success requires an in-depth understanding of the architecture, cellular heterogeneity, and signaling pathways underlying tissue regeneration. Here, we define and spatially map cell populations within the human ureter using single-cell RNA sequencing, spatial gene expression, and immunofluorescence approaches. We focus on the stromal and urothelial cell populations to enumerate the distinct cell types composing the human ureter and infer potential cell-cell communication networks underpinning the bi-directional crosstalk between these compartments. Furthermore, we analyze and experimentally validate the importance of the sonic hedgehog (SHH) signaling pathway in adult progenitor cell maintenance. The SHH-expressing basal cells support organoid generation in vitro and accurately predict the differentiation trajectory from basal progenitor cells to terminally differentiated umbrella cells. Our results highlight the essential processes involved in adult ureter tissue homeostasis and provide a blueprint for guiding ureter tissue engineering.

The urothelium: a multi-faceted barrier against a harsh environment

All mucosal surfaces must deal with the challenge of exposure to the outside world. The urothelium is a highly specialized layer of stratified epithelial cells lining the inner surface of the urinary bladder, a gruelling environment involving significant stretch forces, osmotic and hydrostatic pressures, toxic substances, and microbial invasion. The urinary bladder plays an important barrier role and allows the accommodation and expulsion of large volumes of urine without permitting urine components to diffuse across. The urothelium is made up of three cell types, basal, intermediate, and umbrella cells, whose specialized functions aid in the bladder's mission. In this review, we summarize the recent insights into urothelial structure, function, development, regeneration, and in particular the role of umbrella cells in barrier formation and maintenance. We briefly review diseases which involve the bladder and discuss current human urothelial in vitro models as a complement to traditional animal studies.

Isolation, Identification, Characterization, and Plasmid Profile of Urinary Tract Infectious Escherichia coli from Clinical Samples

Objective

In recent times, urinary tract infection (UTI) is one of the most widely recognized bacterial diseases all over the planet. UTI influences individuals of any age and gender. The target of this study is to concentrate on the recurrence of uropathogens, the antimicrobial susceptibility pattern of the isolates, and the plasmid profile of people from the government clinics of Karaikudi.

Methods

From July 2017 to December 2017, 100 urine tests were gathered and handled for the isolation of pathogenic microbes. In total, 89 isolates were found from the samples collected.

Results

Escherichia coli was discovered as the most common bacterial isolate screened from the UTI-infected people, accounting for 28.09 percent of all isolates. E. coli was seen to be the highest prevalent bacterium for UTI in all age groups and demonstrated resistance to routinely used medications, especially cefpodoxime and novobiocin, which have been 100 percent resistant. The E. coli isolates screened were positive for beta-lactamase and film generation, and they have strong antimicrobial resistance. As a result, the E. coli strains with the highest prevalence of virulence determinants have become more resistant to many medications because they support the microorganism in overcoming the host's defense and colonizing or entering the urinary system. The amplified 16S rRNA product was analyzed, and phylogenetic relationships were determined. The presence of TEM (56 percent), CTX-M (64 percent), SHV (40 percent), and OXA (60 percent) was discovered. Among E. coli isolates, CTX-M was the most common extended spectrum-beta lactamase (ESBL). Multiplex PCR was also used to identify the existence of CTX-M subgroups in E. coli isolates.

Conclusion

Finally, we urge that antibiotic selection should be predicated on the awareness of the specific prevalence and that novel antimicrobial medicines for urinary infections be developed to combat the overuse of antibiotics.

A tissue-engineered urinary conduit in a porcine urinary diversion model

The use of an ileal segment is a standard method for urinary diversion after radical cystectomy. Unfortunately, utilization of this method can lead to numerous surgical and metabolic complications. This study aimed to assess the tissue-engineered artificial conduit for urinary diversion in a porcine model. Tissue-engineered tubular polypropylene mesh scaffolds were used for the right ureter incontinent urostomy model. Eighteen male pigs were divided into three equal groups: Group 1 (control ureterocutaneostomy), Group 2 (the right ureter-artificial conduit-skin anastomoses), and Group 3 (4 weeks before urostomy reconstruction, the artificial conduit was implanted between abdomen muscles). Follow-up was 6 months. Computed tomography, ultrasound examination, and pyelogram were used to confirm the patency of created diversions. Morphological and histological analyses were used to evaluate the tissue-engineered urinary diversion. All animals survived the experimental procedures and follow-up. The longest average patency was observed in the 3rd Group (15.8 weeks) compared to the 2nd Group (10 weeks) and the 1st Group (5.8 weeks). The implant's remnants created a retroperitoneal post-inflammation tunnel confirmed by computed tomography and histological evaluation, which constitutes urostomy. The simultaneous urinary diversion using a tissue-engineered scaffold connected directly with the skin is inappropriate for clinical application.

Retinoic acid signaling and bladder cancer: Epigenetic deregulation, therapy and beyond

Retinoic acid (RA) signaling is a crucial developmental pathway involved in urothelium development, differentiation and regeneration. Deregulation of the RA signaling is highly implicated in several cancers, including bladder cancer, underlying the need to unravel the complete regulatory aspects of the retinoids in bladder tumorigenesis. Given the fact that RA receptors are transcription factors functioning at the chromatin level and act in close cooperation with chromatin modifiers, it is known that retinoids show their efficacy by changing the epigenome. Bladder cancer can be defined as a "disease of chromatin" with mutations identified in the genes involved in chromatin regulation in 80% of the patients. Therefore, a careful examination of the epigenetic backgrounds and the breakdown of the emerging and highly underexplored field of RA dependent regulation of the epigenome is essential to fully understand the retinoid-dependent effects on bladder cancer. With this motivation, in this review, we evaluate the role of RA signaling in bladder cancer with a focus on the regulatory and mutational aspects, emphasizing the deregulatory characteristics in bladder cancer and highlighting the potential treatment opportunities with the RA and derivatives alone or in combination with epigenetic drugs.

Immunohistochemistry as a paramount tool in research of normal urothelium, bladder cancer and bladder pain syndrome

The urothelium, an epithelium of the urinary bladder, primarily functions as blood-urine permeability barrier. The urothelium has a very slow turnover under normal conditions but is capable of extremely fast response to injury. During regeneration urothelium either restores normal function or undergoes altered differentiation pathways, the latter being the cause of several bladder diseases. In this review, we describe the structure of the apical plasma membrane that enables barrier function, the role of urothelium specific proteins uroplakins and the machinery for polarized membrane transports in terminally differentiated superficial umbrella cells. We address key markers, such as keratins, cancer stem cell markers, retinoic acid signalling pathway proteins and transient receptor potential channels and purinergic receptors that drive normal and altered differentiation in bladder cancer and bladder pain syndrome. Finally, we discuss uncertainties regarding research, diagnosis and treatment of bladder pain syndrome. Throughout the review, we emphasise the contribution of immunohistochemistry in advancing our understanding of processes in normal and diseased bladder as well as the most promising possibilities for improved bladder cancer and bladder pain syndrome management.

Long-term survival after radical cystectomy and mesenteric lymph node dissection for squamous cell carcinoma arising from augmented bladder with lymph node metastasis: a case report

Surgical resection is commonly performed for augmented bladder cancer, yet an optimal treatment strategy for augmented bladder cancer with lymph node metastasis has not been established. Here, we report a case that achieved 7 years of survival after radical cystectomy and mesenteric lymph node dissection for squamous cell carcinoma arising from augmented bladder with lymph node metastasis. Extended surgery could be a useful treatment option for locally advanced augmented bladder cancer including mesenteric lymph node metastasis.

The Urothelium: Life in a Liquid Environment

The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.

The effect of botulinum toxin on ureteral inflammation

PURPOSE

The impact of onabotulinum toxin type A (BoNT-A) on bladder afferent nerve pathways and chemosensory functions is an active area of investigation. There may be a role for BoNT-A in disorders of the ureter; however, no histologic studies have assessed the effects of BoNT-A on ureteral tissue. Our objective was to develop an animal model of ureteral inflammation and determine the impact of ureteral BoNT-A instillation on known mechanisms of inflammation.

METHODS

The safety and feasibility of a novel animal model of ureteral inflammation was assessed. Through open cystotomy, the effect of ureteral BoNT-A instillation on inflammation was determined through H&E, masson's trichrome, Ki-67 stain, and prostaglandin E (PGE) synthase expression, a known marker of pain and inflammation in ureteral tissue. Urothelial microstructure was assessed using electron microscopy and standard histologic techniques.

RESULTS

All experiments were carried to completion, and no systemic signs of botulinum toxicity were seen. BoNT-A exposure was associated with a decrease in PGE synthase expression in a dose-dependent fashion. BoNT-A exposure was not found to impact collagen deposition or cell proliferation. Disruption of tight junctions between urothelial cells was observed under conditions of inflammation.

CONCLUSION

We describe the feasibility of a novel in vivo model of ureteral inflammation and report the first histologic study of the effects of BoNT-A on the ureter. Preliminary findings show that BoNT-A attenuates ureteral PGE synthase expression under conditions of inflammation. The application of BoNT-A may provide anti-inflammatory and analgesic effects in the context of ureteral disorders.

Vitamin A Rich Diet Diminishes Early Urothelial Carcinogenesis by Altering Retinoic Acid Signaling

Urinary bladder cancer is one of the leading malignancies worldwide, with the highest recurrence rates. A diet rich in vitamin A has proven to lower the risk of cancer, yet the molecular mechanisms underlying this effect are unknown. We found that vitamin A decreased urothelial atypia and apoptosis during early bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Vitamin A did not alter urothelial cell desquamation, differentiation, or proliferation rate. Genes like Wnt5a, involved in retinoic acid signaling, and transcription factors Pparg, Ppara, Rxra, and Hoxa5 were downregulated, while Sox9 and Stra6 were upregulated in early urothelial carcinogenesis. When a vitamin A rich diet was provided during BBN treatment, none of these genes was up- or downregulated; only Lrat and Neurod1 were upregulated. The lecithin retinol acyltransferase (LRAT) enzyme that produces all-trans retinyl esters was translocated from the cytoplasm to the nuclei in urothelial cells as a consequence of BBN treatment regardless of vitamin A rich diet. A vitamin A-rich diet altered retinoic acid signaling, decreased atypia and apoptosis of urothelial cells, and consequently diminished early urothelial carcinogenesis.

Is Schistosomiasis a Risk Factor for Bladder Cancer? Evidence-Based Facts

Background . Globally, approximately 20% of malignancy are caused by infection. Schistosoma infection is a major cause of bladder in most part of Africa. In 2018 alone, there were approximately 549,393 new cases and 199,922 deaths from bladder cancer. The presence of Schistosoma ova in the venous plexus of the bladder induces a cascade of inflammation causing significant tissue damage and granulomatous changes. Methodology. A literature review was conducted from 1995 to 2019 using PubMed, Google Scholar, African Journal Online, and Google databases. Relevant data on the association of "Schistosomiasis and Bladder cancer" in sub-Saharan Africa (SSA) were retrieved. Evidence Synthesis. Results from research using animal models to establish the carcinogenesis of Schistosoma and bladder cancer have been helpful but inconclusive. Immunoregulatory cytokines and genetic marker have been identified to play a role in the pathogenesis. In some parts of sub-Saharan Africa, there has been close association of squamous cell carcinoma and histological evidence of Schistosoma ova. Conclusion. There are some data to support the association between schistosomiasis and bladder cancer in sub-Saharan Africa. However, these have been limited by their design and may not sufficiently establish carcinogenesis. There is a need for more genomic and molecular research to better characterize S. haematobium and its effects on the bladder. Such goal will contribute immensely to Schistosoma bladder cancer prevention and control.

Loricrin: Past, Present, and Future

The terminal differentiation of the epidermis is a complex physiological process. During the past few decades, medical genetics has shown that defects in the stratum corneum (SC) permeability barrier cause a myriad of pathological conditions, ranging from common dry skin to lethal ichthyoses. Contrarily, molecular phylogenetics has revealed that amniotes have acquired a specialized form of cytoprotection cornification that provides mechanical resilience to the SC. This superior biochemical property, along with desiccation tolerance, is attributable to the proper formation of the macromolecular protein-lipid complex termed cornified cell envelopes (CE). Cornification largely depends on the peculiar biochemical and biophysical properties of loricrin, which is a major CE component. Despite its quantitative significance, loricrin knockout (LKO) mice have revealed it to be dispensable for the SC permeability barrier. Nevertheless, LKO mice have brought us valuable lessons. It is also becoming evident that absent loricrin affects skin homeostasis more profoundly in many more aspects than previously expected. Through an extensive review of aggregate evidence, we discuss herein the functional significance of the thiol-rich protein loricrin from a biochemical, genetic, pathological, metabolic, or immunological aspect with some theoretical and speculative perspectives.

Re-evaluation of histological findings after colocystoplasty and gastrocystoplasty

INTRODUCTION

The potential of malignant transformation and its risk factors after bladder augmentation performed in childhood are still unknown. The necessity of surveillance cystoscopies and biopsies has been questioned in the past decade.

OBJECTIVE

In a previous study, the authors did not detect any malignancy after colocystoplasty (CCP) or gastrocystoplasty (GCP) during the short-term follow-up, however, various alterations of the mucosa were found. A correlation between the nature of histological changes and the frequency of bacterial colonization after CCP were also found. The authors hypothesized that a longer-term follow-up of their patients would reveal an increase in pathological change or show stronger association between the histological alteration, bacterial colonization, and/or stone formation.

PATIENTS AND METHODS

Thirty-five patients (20 cases of colocystoplasties - CCPs; 15 cases of gastrocystoplasties - GCPs) participated in the study published in 2002. All patients were followed biannually with endoscopic assessment and biopsies. Two independent pathologists, evaluated regular biopsies from the native bladder, from the segment used for augmentation and from the anastomosis line. Etiology, frequency of positive urine cultures, and stone events were recorded and compared with histological findings between groups and with the previously published results.

RESULTS

Continuous surveillance allowed the follow-up of 30 patients (CCP 19/20, GCP 11/15) for 20 and 15 years. No malignancies were identified. Results of biopsies showed significant difference between groups (summarized in the tables). Chronic inflammatory changes were found following both types of augmentations, but they were more common in the urothelium following GCP and more common in the colonic mucosa following CCP. The rate of metaplastic lesions was higher after gastrocystoplasty (GCP). Significant association was found between the etiologic factor and the nature of histological change after CCP, as metaplastic lesions occurred only in patients with bladder exstrophy. Stones occurred more frequently in exstrophy patients as well. The nature of the histological changes did not correlate with positive urine cultures in either of the groups. Significantly higher incidence of bacterial colonization and stone occurrence were found after CCP.

CONCLUSIONS

Long-term follow-up of the patients failed to reveal an increase in pathological changes, and no malignancies were observed. According to the results of this study, etiology of bladder dysfunction and the type of augmentation might influence the histological alterations after augmentation cystoplasty. The efficiency of surveillance cystoscopies and biopsies are low. The present data suggest that surveillance cystoscopy and biopsy should not be routinely performed, and should be done only if the symptoms are suspicious for malignancy.

Uroplakins play conserved roles in egg fertilization and acquired additional urothelial functions during mammalian divergence

Uroplakin (UP) tetraspanins and their associated proteins are major mammalian urothelial differentiation products that form unique two-dimensional crystals of 16-nm particles (“urothelial plaques”) covering the apical urothelial surface. Although uroplakins are highly expressed only in mammalian urothelium and are often referred to as being urothelium specific, they are also expressed in several mouse nonurothelial cell types in stomach, kidney, prostate, epididymis, testis/sperms, and ovary/oocytes. In oocytes, uroplakins colocalize with CD9 on cell-surface and multivesicular body-derived exosomes, and the cytoplasmic tail of UPIIIa undergoes a conserved fertilization-dependent, Fyn-mediated tyrosine phosphorylation that also occurs in Xenopus laevis eggs. Uroplakin knockout and antibody blocking reduce mouse eggs’ fertilization rate in in vitro fertilization assays, and UPII/IIIa double-knockout mice have a smaller litter size. Phylogenetic analyses showed that uroplakin sequences underwent significant mammal-specific changes. These results suggest that, by mediating signal transduction and modulating membrane stability that do not require two-dimensional-crystal formation, uroplakins can perform conserved and more ancestral fertilization functions in mouse and frog eggs. Uroplakins acquired the ability to form two-dimensional-crystalline plaques during mammalian divergence, enabling them to perform additional functions, including umbrella cell enlargement and the formation of permeability and mechanical barriers, to protect/modify the apical surface of the modern-day mammalian urothelium.

Update of the International Consultation on Urological Diseases on bladder cancer 2018: non-urothelial cancers of the urinary bladder

PURPOSE

To provide a comprehensive update of the joint consultation of the International Consultation on Urological Diseases (ICUD) for the diagnosis and management of non-urothelial cancer of the urinary bladder.

METHODS

A detailed analysis of the literature was conducted reporting on the epidemiology, etiology, diagnosis, treatment and outcomes of non-urothelial cancer of the urinary bladder. An international, multidisciplinary expert committee evaluated and graded the evidence according to the Oxford System of Evidence-based Medicine modified by the ICUD.

RESULTS

The major non-urothelial cancers of the urinary bladder are squamous cell carcinoma, adenocarcinoma, and neuroendocrine tumors. Several other non-urothelial tumors are rare but important to identify because of their aggressive behavior when compared to urothelial bladder tumors. Radical cystectomy and urinary diversion, preceded by neoadjuvant radiation or chemotherapy in some of these tumors, is the main method or treatment for resectable disease. Adjuvant therapy is not usually successful and no novel targeted or immunotherapeutic agents have been identified to provide benefit. Patients with small cell neuroendocrine tumors of the bladder should be offered chemotherapy before surgery. Because non-urothelial cancers are usually locally advanced and/or metastatic at the time of diagnosis, 5-year survival is generally poor.

CONCLUSIONS

Non-urothelial cancers of the urinary bladder are rare and mostly lack established protocols for treatment. The prognosis of most of these tumors is poor because they are usually advanced at the time of diagnosis. A multimodal treatment approach should be considered to improve outcomes.

Changes of bladder mucosal inflammatory factors and prognosis in cystitis glandularis

Objective: To investigate the relationships of bladder mucosal inflammatory factors, interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) with the occurrence and development of cystitis glandularis (CG), and their effects on the prognosis. Methods: A total of 61 patients with CG from January 2010 to 2014 were randomly selected. Tissue specimens of postoperative patients were collected. 16 cases of normal bladder mucosa during the same period were collected as a control group. Blood specimens and fresh tissue specimens were collected from 6 patients with CG. The messenger ribonucleic acid (mRNA) levels of IL-1, IL-6 and TNF-α were detected via reverse transcription polymerase chain reaction (RT-PCR). The protein levels of IL-1, IL-6 and TNF-α in serum of patients with GC and normal controls were detected via an enzyme-linked immunosorbent assay (ELISA). The protein expressions of IL-1, IL-6 and TNF-α were detected via immunohistochemistry (IHC), and their relationships with the clinical features and prognosis of GC were analyzed. A Cox proportional hazard regression model was used for multivariate analysis on the prognostic factors of CG, and all the tests were performed with 95% confidence interval (CI). Results: The protein expressions of IL-1, IL-6 and TNF-α in patients with CG were obviously higher than those in normal group. The mRNA levels of IL-1, IL-6 and TNF-α in the serum of patients with CG were also significantly higher than those in normal group (P<0.05). The expressions of IL-1, IL-6 and TNF-α in CG were positively correlated. TNF-α is an independent prognostic factor of CG. Conclusion: IL-1, IL-6 and TNF-α are associated with the occurrence and development of CG. TNF-α presents as an independent prognostic factor of CG that can be used for the diagnosis of cystitis glandularis.

A case report of intrarenal epidermoid cysts in a yellow-bellied slider (Trachemys scripta scripta)

A 7-year-old yellow-bellied slider exhibited anorexia, decreased activity, generalised wasting of skeletal muscles and oedema. Haematology examination revealed increased phosphorus and decreased calcium levels. During necropsy performed after spontaneous death, a focal nodular lesion containing tan amorphous material was found in the left kidney. Histopathology examination revealed multiple cystic lesions lined by a multilayered squamous, occasionally cuboidal, and containing keratin. Epithelial cells and keratin material were cytokeratin-positive. These findings confirmed a diagnosis of the most likely congenital intrarenal epidermoid cysts.

Squamous differentiation in patients with superficial bladder urothelial carcinoma is associated with high risk of recurrence and poor survival

Background

The independent prognostic role of squamous differentiation in pT1 bladder urothelial carcinoma has not been reported in previous studies. This article describes the impact of squamous differentiation on tumor recurrence and survival, and whether this histologic variant could indeed alter definitive treatment, based on single center-based retrospective data.

Methods

Totally, we retrieved (1)1449 histologically confirmed pT1 bladder urothelial carcinoma patients without histologic variants; (2)227 pT1 bladder urothelial carcinoma patients with squamous differentiation in our institution, from May 2004 to Oct 2015. The total amount of high/low grade urothelial carcinoma patients was 991/685 respectively. Transurethral resection of bladder tumor (TURBT) and intravesical chemotherapy were performed as initial treatments for all the patients. The clinical and pathological characteristics, treatment and survival outcomes were compared between squamous differentiation-positive and squamous differentiation-negative patients.

Results

In our study, 14% urothelial carcinoma patients were detected with squamous differentiation. The mean age of all the patients examined was 66.4, of whom 82% were males. The 5-year cancer specific survival rates were 69% for squamous differentiation-positive patients and 91% for squamous differentiation-negative patients (p < 0.001). Recurrence proved to be more common in squamous differentiation-positive patients than in negative patients. In the results of the univariate and multivariate Cox proportional hazard analysis, tumor size, lymphovascular invasion, recurrence and squamous differentiation were confirmed to be the prognostic factors associated with patients’ survival.

Conclusions

Squamous differentiation in pT1 bladder urothelial carcinoma is correlated to high risk of recurrence and poor prognosis as an independent prognostic factor. Radical cystectomy is essential for recurred high grade pT1 bladder urothelial carcinoma with squamous differentiation accompanied by lymphovascular invasion.

Sleeping beauty: awakening urothelium from its slumber

The bladder urothelium is essentially quiescent but regenerates readily upon injury. The process of urothelial regeneration harkens back to the process of urothelial development whereby urothelial stem/progenitor cells must proliferate and terminally differentiate to establish all three urothelial layers. How the urothelium regulates the level of proliferation and the timing of differentiation to ensure the precise degree of regeneration is of significant interest in the field. Without a carefully-orchestrated process, urothelial regeneration may be inadequate, thereby exposing the host to toxins or pathogens. Alternatively, regeneration may be excessive, thereby setting the stage for tumor development. This review describes our current understanding of urothelial regeneration. The current controversies surrounding the identity and location of urothelial progenitor cells that mediate urothelial regeneration are discussed and evidence for each model is provided. We emphasize the factors that have been shown to be crucial for urothelial regeneration, including local growth factors that stimulate repair, and epithelial-mesenchymal cross talk, which ensures feedback regulation. Also highlighted is the emerging concept of epigenetic regulation of urothelial regeneration, which additionally fine tunes the process through transcriptional regulation of cell cycle genes and growth and differentiation factors. Finally, we emphasize how several of these pathways and/or programs are often dysregulated during malignant transformation, further corroborating their importance in directing normal urothelial regeneration. Together, evidence in the field suggests that any attempt to exploit regenerative programs for the purposes of enhanced urothelial repair or replacement must take into account this delicate balance.

Urothelial generation and regeneration in development, injury, and cancer

Homeostatic maintenance and repair of the urothelium upon injury are required for a functional bladder in both healthy and disease conditions. Understanding the cellular and molecular mechanisms underlying the urothelial regenerative response is key to designing strategies for tissue repair and ultimately treatments for urologic diseases including urinary tract infections, voiding dysfunction, painful bladder syndrome, and bladder cancer. In this article, we review studies on urothelial ontogeny during development and regeneration following various injury modalities. Signaling pathways involved in urothelial regeneration and in urothelial carcinogenesis are also discussed. Developmental Dynamics 246:336-343, 2017. © 2016 Wiley Periodicals, Inc.

[Urinary schistosomiasis and cancer]

The existence of a link between urinary schistosomiasis (US) and bladder carcinoma was first suspected by C. Goebel in 1905. In 1911, A.R Ferguson, who was a professor of Pathology and Microbiology at the Faculty of Medicine in Cairo, published a more detailed survey from 40 autopsies, and reported a likely association of bladder carcinoma with granulomas caused by US. Subsequently, published results from several studies reinforced Ferguson's hypothesis. Moreover, in most countries where US was endemic, association of high prevalence of bladder carcinoma with US had been pointed out. A further circumstantial evidence was a higher prevalence of bladder squamous cell carcinoma in areas endemic for SU, whereas urothelial carcinomas were more prevalent in areas which were free of SU. However, evidence of a positive correlation between SU and bladder carcinoma was delivered only many decades later, following the results from case-control studies which were adjusted on age, sex, type of dwelling and tobacco consumption. During SU, the mechanisms underlying the onset of bladder carcinoma are still poorly understood due to the lack of any convenient animal model. Classically, two processes are thought to be involved. Chronic inflammation inside bladder would be caused by granulomas centered by eggs, and would result in a neoplasmic evolution, after years. Moreover, alteration of the bladder dynamics would elicit urine stasis which in turn would cause repeated infection of bacterial or viral origin. Beside the high prevalence of squamous cell type, the natural history of bladder carcinomas caused by SU is similar to that of other malignant tumors of the bladder. Also the treatment and prognosis are identical. Albeit genital involvement is very frequent during SU, Schistosoma haematobium does not appear to be a cause of cancers of genital organs. Schistosoma mansoni and S. japonicum have been suspected to be associated with liver or colic carcinomas, but epidemiological studies have not yielded any firm evidence so far. The entire sequencing of S. haematobium genome, along with the recent availability of a more efficient mouse model, must provide a better understanding of the genesis of bladder carcinomas during SU. However, the key for a sharp decrease in both morbidity and mortality due to SU-linked carcinomas lies in a better control of haematobium schistosomiasis, such as observed in Egypt since 1970.

Hierarchical transcriptional profile of urothelial cells development and differentiation

The urothelial lining of the lower urinary tract is the most efficient permeability barrier in animals, exhibiting a highly differentiated phenotype and a remarkable regenerative capacity upon wounding. During development and possibly during repair, cells undergo a sequence of hierarchical transcriptional events that mark the transition of these cells from the least differentiated urothelial phenotype characteristic of the basal cell layer, to the most differentiated cellular phenotype characteristic of the superficial cell layer. Unraveling normal urothelial differentiation program is essential to uncover the underlying causes of many congenital abnormalities and for the development of an appropriate differentiation niche for stem cells, for future use in urinary tract tissue engineering and organ reconstruction. Kruppel like factor-5 appears to be at the top of the hierarchy activating several downstream transcription factors, the most prominent of which is peroxisome proliferator activator receptor-γ. Eventually those lead to the activation of transcription factors that directly regulate the expression of uroplakin proteins along with other proteins that mediate the permeability function of the urothelium. In this review, we discuss the most recent findings in the area of urothelial cellular differentiation and transcriptional regulation, aiming for a comprehensive overview that aids in a refined understanding of this process.

Stage- and subunit-specific functions of polycomb repressive complex 2 in bladder urothelial formation and regeneration

Urothelium is the protective lining of the urinary tract. The mechanisms underlying urothelial formation and maintenance are largely unknown. Here, we report the stage-specific roles of PRC2 epigenetic regulators in embryonic and adult urothelial progenitors. Without Eed, the obligatory subunit of PRC2, embryonic urothelial progenitors demonstrate reduced proliferation with concomitant dysregulation of genes including Cdkn2a (p16), Cdkn2b (p15) and Shh. These mutants display premature differentiation of keratin 5-positive (Krt5⁺) basal cells and ectopic expression of squamous-like differentiation markers. Deletion of Ezh2, the major enzymatic component of PRC2, causes upregulation of Upk3a⁺ superficial cells. Unexpectedly, Eed and Eed/Ezh2 double mutants exhibit delayed superficial cell differentiation. Furthermore, Eed regulates the proliferative and regenerative capacity of adult urothelial progenitors and prevents precocious differentiation. Collectively, these findings uncover the epigenetic mechanism by which PRC2 controls urothelial progenitor cell fate and the timing of differentiation, and further suggest an epigenetic basis of urothelial maintenance and regeneration.

On a FOX hunt: functions of FOX transcriptional regulators in bladder cancer

Genomic and transcriptional studies have identified discrete molecular subtypes of bladder cancer. These observations could be the starting point to identify new treatments. Several members of the forkhead box (FOX) superfamily of transcription factors have been found to be differentially expressed in the different bladder cancer subtypes. In addition, the FOXA protein family are key regulators of embryonic bladder development and patterning. Both experimental and clinical data support a role for FOXA1 and FOXA2 in urothelial carcinoma. FOXA1 is expressed in embryonic and adult urothelium and its expression is altered in urothelial carcinomas and across disparate molecular bladder cancer subtypes. FOXA2 is normally absent from the adult urothelium, but developmental studies identified FOXA2 as a marker of a transient urothelial progenitor cell population during bladder development. Studies also implicate FOXA2 in bladder cancer and several other FOX proteins might be involved in development and/or progression of this disease; for example, FOXA1 and FOXO3A have been associated with clinical patient outcomes. Future studies should investigate to what extent and by which mechanisms FOX proteins might be directly involved in bladder cancer pathogenesis and treatment responses.

Effects of CYP-Induced Cystitis on Growth Factors and Associated Receptor Expression in Micturition Pathways in Mice with Chronic Overexpression of NGF in Urothelium

We have determined if cyclophosphamide (CYP)-induced cystitis produces additional changes in growth factor/receptors expression in the urinary bladder (urothelium, detrusor) and lumbosacral (L6-S1) dorsal root ganglia (DRG) in a transgenic mouse model with chronic urothelial overexpression of NGF (NGF-OE). Functionally, NGF-OE mice treated with CYP exhibit significant increases in voiding frequency above that observed in control NGF-OE mice (no CYP). Quantitative PCR was used to determine NGF, BDNF, VEGF, and receptors (TrkA, TrkB, p75(NTR)) transcripts expression in tissues from NGF-OE and wild-type (WT) mice with CYP-induced cystitis of varying duration (4 h, 48 h, 8 days). In urothelium of control NGF-OE mice, NGF mRNA was significantly (p ≤ 0.001) increased. Urothelial expression of NGF mRNA in NGF-OE mice treated with CYP (4 h, 48 h, 8 days) was not further increased but maintained with all durations of CYP treatment evaluated. In contrast, CYP-induced cystitis (4 h, 48 h, 8 days) in NGF-OE mice demonstrated significant (p ≤ 0.05) regulation in BDNF, VEGF, TrkA, TrkB, and P75(NTR) mRNA in urothelium and detrusor smooth muscle. Similarly, CYP-induced cystitis (4 h, 48 h, 8 days) in NGF-OE mice resulted in significant (p ≤ 0.05), differential changes in transcript expression for NGF, BDNF, and receptors (TrkA, TrkB, p75(NTR)) in S1 DRG that was dependent on the duration-of CYP-induced cystitis. In general, NGF, BDNF, TrkA, and TrkB protein content in the urinary bladder increased in WT and NGF-OE mice with CYP-induced cystitis (4 h). Changes in NGF, TrkA and TrkB expression in the urinary bladder were significantly (p ≤ 0.05) greater in NGF-OE mice with CYP-induced cystitis (4 h) compared to WT mice with cystitis (4 h). However, the magnitude of change between WT and NGF-OE mice was only significantly (p ≤ 0.05) different for TrkB expression in urinary bladder of NGF-OE mice treated with CYP. These studies are consistent with target-derived NGF and other inflammatory mediators affecting neurochemical plasticity with potential contributions to reflex function of micturition pathways.

Intravesical PAC1 Receptor Antagonist, PACAP(6-38), Reduces Urinary Bladder Frequency and Pelvic Sensitivity in NGF-OE Mice

Chronic NGF overexpression (OE) in the urothelium, achieved through the use of a highly urothelium-specific uroplakin II promoter, stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency and non-voiding contractions, and referred somatic sensitivity. Additional NGF-mediated pleiotropic changes might contribute to increased voiding frequency and pelvic hypersensitivity in NGF-OE mice such as neuropeptide/receptor systems including PACAP(Adcyap1) and PAC1 receptor (Adcyap1r1). Given the presence of PAC1-immunoreactive fibers and the expression of PAC1 receptor expression in bladder tissues, and PACAP-facilitated detrusor contraction, whether PACAP/receptor signaling contributes to increased voiding frequency and somatic sensitivity was evaluated in NGF-OE mice. Intravesical administration of the PAC1 receptor antagonist, PACAP(6-38) (300 nM), significantly (p ≤ 0.01) increased intercontraction interval (2.0-fold) and void volume (2.5-fold) in NGF-OE mice. Intravesical instillation of PACAP(6-38) also decreased baseline bladder pressure in NGF-OE mice. PACAP(6-38) had no effects on bladder function in WT mice. Intravesical administration of PACAP(6-38) (300 nM) significantly (p ≤ 0.01) reduced pelvic sensitivity in NGF-OE mice but was without effect in WT mice. PACAP/receptor signaling contributes to the increased voiding frequency and pelvic sensitivity observed in NGF-OE mice.

[Preneoplastic lesions and precursors of urothelial cancer]

As even a mere thickening of the urothelium can harbor genetic changes identical to that of low grade papillary urothelial tumors, it is not always possible to clearly recognize a precursor lesion of urothelial carcinoma by routine histological diagnostics. Complementary immunohistochemical and molecular diagnostic methods assist the recognition of these entities. These methods especially help to identify clinically important genetically unstable cells as the hallmark of carcinoma in situ (CIS). Little is known about the clinical significance of the morphological subtypes of CIS, which range from large cell to micropapillary variants. For a better understanding of special types of bladder cancer (e.g. adenocarcinoma and squamous cell carcinoma), it seems to be important to define the phenotype and the molecular pattern of non-urothelial lesions, such as intestinal metaplasia and squamous metaplasia, better and more precisely.

Loss of FOXA1 Drives Sexually Dimorphic Changes in Urothelial Differentiation and Is an Independent Predictor of Poor Prognosis in Bladder Cancer

We previously found loss of forkhead box A1 (FOXA1) expression to be associated with aggressive urothelial carcinoma of the bladder, as well as increased tumor proliferation and invasion. These initial findings were substantiated by The Cancer Genome Atlas, which identified FOXA1 mutations in a subset of bladder cancers. However, the prognostic significance of FOXA1 inactivation and the effect of FOXA1 loss on urothelial differentiation remain unknown. Application of a univariate analysis (log-rank) and a multivariate Cox proportional hazards regression model revealed that loss of FOXA1 expression is an independent predictor of decreased overall survival. An ubiquitin Cre-driven system ablating Foxa1 expression in urothelium of adult mice resulted in sex-specific histologic alterations, with male mice developing urothelial hyperplasia and female mice developing keratinizing squamous metaplasia. Microarray analysis confirmed these findings and revealed a significant increase in cytokeratin 14 expression in the urothelium of the female Foxa1 knockout mouse and an increase in the expression of a number of genes normally associated with keratinocyte differentiation. IHC confirmed increased cytokeratin 14 expression in female bladders and additionally revealed enrichment of cytokeratin 14-positive basal cells in the hyperplastic urothelial mucosa in male Foxa1 knockout mice. Analysis of human tumor specimens confirmed a significant relationship between loss of FOXA1 and increased cytokeratin 14 expression.

Combined cytotoxic effect of UV-irradiation and TiO2 microbeads in normal urothelial cells, low-grade and high-grade urothelial cancer cells

The differentiation of urothelial cells results in normal terminally differentiated cells or by alternative pathways in low-grade or high-grade urothelial carcinomas. Treatments with traditional surgical and chemotherapeutical approaches are still inadequate and expensive, as bladder tumours are generally highly recurrent. In such situations, alternative approaches, using irradiation of the cells and nanoparticles, are promising. The ways in which urothelial cells, at different differentiation levels, respond to UV-irradiation (photolytic treatment) or to the combination of UV-irradiation and nanoparticles (photocatalytic treatment), are unknown. Here we tested cytotoxicity of UV-irradiation on (i) normal porcine urothelial cells (NPU), (ii) human low-grade urothelial cancer cells (RT4), and (iii) human high-grade urothelial cancer cells (T24). The results have shown that 1 minute of UV-irradiation is enough to kill 90% of the cells in NPU and RT4 cultures, as determined by the live/dead viability assay. On the other hand, the majority of T24 cells survived 1 minute of UV-irradiation. Moreover, even a prolonged UV-irradiation for 30 minutes killed <50% of T24 cells. When T24 cells were pre-supplemented with mesoporous TiO2 microbeads and then UV-irradiated, the viability of these high-grade urothelial cancer cells was reduced to <10%, which points to the highly efficient cytotoxic effects of TiO2 photocatalysis. Using electron microscopy, we confirmed that the mesoporous TiO2 microbeads were internalized into T24 cells, and that the cell's ultrastructure was heavily compromised after UV-irradiation. In conclusion, our results show major differences in the sensitivity to UV-irradiation among the urothelial cells with respect to cell differentiation. To achieve an increased cytotoxicity of urothelial cancer cells, the photocatalytic approach is recommended.

Altered expression of CKs 14/20 is an early event in a rat model of multistep bladder carcinogenesis

Cytokeratins (CKs) 14 and 20 are promising markers for diagnosing urothelial lesions and for studying their prognosis and histogenesis. This work aimed to study the immunohistochemical staining patterns of CK14/20 during multistep carcinogenesis leading to papillary bladder cancer in a rat model. Thirty female Fischer 344 rats were divided into three groups: group 1 (control); group 2, which received N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 20 weeks plus 1 week without treatment; and group 3, which received BBN for 20 weeks plus 8 weeks without treatment. Bladder lesions were classified histologically. CK14 and CK20 immunostaining was assessed according to its distribution and intensity. In control animals, 0-25% of basal cells and umbrella cells stained positive for CK14 and CK20 respectively. On groups 2 and 3, nodular hyperplastic lesions showed normal CK20 and moderately increased CK14 staining (26-50% of cells). Dysplasia, squamous metaplasia, papilloma, papillary tumours of low malignant potential and low- and high-grade papillary carcinomas showed increased CK14 and CK20 immunostaining in all epithelial layers. Altered CK14 and CK20 expression is an early event in urothelial carcinogenesis and is present in a wide spectrum of urothelial superficial neoplastic and preneoplastic lesions.

Molecular mechanisms of squamous differentiation in urothelial cell carcinoma: a paradigm for molecular subtyping of urothelial cell carcinoma of the bladder

BACKGROUND

Recent molecular characterization studies focusing on bladder cancer have provided a wealth of information, including the identification of specific molecular subtypes of this disease. Interestingly, a particular molecular subtype identified by several different groups is characterized, at least in part, by the presence of squamous differentiation (SqD) in a significant fraction of primary tumors. Tumors that exhibit SqD are extremely aggressive. Moreover, conflicting reports exist relative to the sensitivity of bladder tumors exhibiting SqD to multimodal treatment. Bladder cancers that exhibit SqD appear to be distinct clinical entities and are often associated with a specific molecular subtype; therefore, it is important to understand the molecular drivers of this process.

PURPOSE

Because presence of SqD is closely associated with a basal molecular phenotype, we review the evidence for specific pathways in SqD. In addition, we pose key areas for future exploration.

Anatomy and Physiology of the Urinary Tract: Relation to Host Defense and Microbial Infection

The urinary tract exits to a body surface area that is densely populated by a wide range of microbes. Yet, under most normal circumstances, it is typically considered sterile, i.e., devoid of microbes, a stark contrast to the gastrointestinal and upper respiratory tracts where many commensal and pathogenic microbes call home. Not surprisingly, infection of the urinary tract over a healthy person's lifetime is relatively infrequent, occurring once or twice or not at all for most people. For those who do experience an initial infection, the great majority (70% to 80%) thankfully do not go on to suffer from multiple episodes. This is a far cry from the upper respiratory tract infections, which can afflict an otherwise healthy individual countless times. The fact that urinary tract infections are hard to elicit in experimental animals except with inoculum 3-5 orders of magnitude greater than the colony counts that define an acute urinary infection in humans (105 cfu/ml), also speaks to the robustness of the urinary tract defense. How can the urinary tract be so effective in fending off harmful microbes despite its orifice in a close vicinity to that of the microbe-laden gastrointestinal tract? While a complete picture is still evolving, the general consensus is that the anatomical and physiological integrity of the urinary tract is of paramount importance in maintaining a healthy urinary tract. When this integrity is breached, however, the urinary tract can be at a heightened risk or even recurrent episodes of microbial infections. In fact, recurrent urinary tract infections are a significant cause of morbidity and time lost from work and a major challenge to manage clinically. Additionally, infections of the upper urinary tract often require hospitalization and prolonged antibiotic therapy. In this chapter, we provide an overview of the basic anatomy and physiology of the urinary tract with an emphasis on their specific roles in host defense. We also highlight the important structural and functional abnormalities that predispose the urinary tract to microbial infections.

Glycosylation of uroplakins. Implications for bladder physiopathology

Urothelium, a specialized epithelium, covers the urinary tract and act not only as a barrier separating its light from the surrounding tissues, but fulfills an important role in maintaining the homeostasis of the urothelial tract and well-being of the whole organism. Proper function of urothelium is dependent on the precise assemble of highly specialized glycoproteins called uroplakins, the end products and differentiation markers of the urothelial cells. Glycosylation changes in uroplakins correlate with and might reflect progressive stages of pathological conditions of the urothelium such as cancer, urinary tract infections, interstitial cystitis and others. In this review we focus on sugar components of uroplakins, their emerging role in urothelial biology and disease implications. The advances in our understanding of uroplakins changes in glycan moieties composition, structure, assembly and expression of their glycovariants could potentially lead to the development of targeted therapies and discoveries of novel urine and plasma markers for the benefit of patients with urinary tract diseases.

In vivo disruption of an Rb-E2F-Ezh2 signaling loop causes bladder cancer

Bladder cancer is a highly prevalent human disease in which retinoblastoma (Rb) pathway inactivation and epigenetic alterations are common events. However, the connection between these two processes is still poorly understood. Here, we show that the in vivo inactivation of all Rb family genes in the mouse urothelium is sufficient to initiate bladder cancer development. The characterization of the mouse tumors revealed multiple molecular features of human bladder cancer, including the activation of E2F transcription factor and subsequent Ezh2 expression and the activation of several signaling pathways previously identified as highly relevant in urothelial tumors. These mice represent a genetically defined model for human high-grade superficial bladder cancer. Whole transcriptional characterizations of mouse and human bladder tumors revealed a significant overlap and confirmed the predominant role for Ezh2 in the downregulation of gene expression programs. Importantly, the increased tumor recurrence and progression in human patients with superficial bladder cancer is associated with increased E2F and Ezh2 expression and Ezh2-mediated gene expression repression. Collectively, our studies provide a genetically defined model for human high-grade superficial bladder cancer and demonstrate the existence of an Rb-E2F-Ezh2 axis in bladder whose disruption can promote tumor development.

Quantitative analysis of the association between sulfotransferase isoform 1A1 polymorphism and risk of urothelial carcinoma

Sulfotransferase isoform 1A1 (SULT1A1) is a member of the sulfotransferase family that plays an important role in the biotransformation of numerous carcinogenic and mutagenic compounds through sulfation. A number of case-control studies were conducted to investigate the association between the Arg213His polymorphism in SULT1A1 and the risk of urothelial carcinoma (UC) in humans. However, the results were inconsistent. A meta-analysis based on 10 case-control studies was performed to address this issue. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of this association. Between-study heterogeneity was assessed with the Chi-square-based Q test. Overall, a possibly decreased risk of UC was associated with the SULT1A1 A/A polymorphism for the heterozygote model (OR=0.86, 95% CI: 0.76-0.98, P=0.471). In the subgroup analysis by cancer type, the results indicated that individuals with the G/G genotype had a significantly higher bladder cancer (BC) risk (GA vs. GG: OR=0.88, 95% CI: 0.74-0.99, P=0.626; GA/AA vs. GG: OR=0.85, 95% CI: 0.74-0.97, P=0.504), which was contrary to the results of the upper urinary tract urothelial carcinoma (UTUC) group (AA vs. GG: OR=2.18, 95% CI: 1.28-3.69; AA vs.

GA/GG

OR=2.05, 95% CI: 1.24-3.38). In addition, stratification by smoking status demonstrated that the Arg213His polymorphism was associated with a decreased risk of UC in non-smokers (OR=0.70, 95% CI: 0.53-0.92) but not in smokers (OR=0.85, 95% CI: 0.70-1.03) under the dominant model. In conclusion, this meta-analysis demonstrated a significant association between the SULT1A1 Arg213His polymorphism and BC. However, there was insufficient evidence to support a consistent association between this polymorphism and UC, partly due to the differences between BC and UTUC.

Controversies and challenges in research on urogenital schistosomiasis-associated bladder cancer

Urogenital schistosomiasis, infection with Schistosoma haematobium, is linked to increased risk for the development of bladder cancer, but the importance of various mechanisms responsible for this association remains unclear, in part, owing to lack of sufficient and appropriate animal models. New advances in the study of this parasite, bladder regenerative processes, and human schistosomal bladder cancers may shed new light on the complex biological processes that connect S. haematobium infection to bladder carcinogenesis.

MicroRNA-205 targets tight junction-related proteins during urothelial cellular differentiation

The mammalian bladder urothelium classified as basal, intermediate, and terminally differentiated umbrella cells offers one of the most effective permeability barrier functions known to exist in nature because of the formation of apical uroplakin plaques and tight junctions. To improve our understanding of urothelial differentiation, we analyzed the microRNA (miRNA) expression profiles of mouse urinary tissues and by TaqMan miRNA analysis of microdissected urothelial layers and in situ miRNA-specific hybridization to determine the dependence of these miRNAs on the differentiation stage. Our in situ hybridization studies revealed that miR-205 was enriched in the undifferentiated basal and intermediate cell layers. We then used a quantitative proteomics approach to identify miR-205 target genes in primary cultured urothelial cells subjected to antagomir-mediated knockdown of specific miRNAs. Twenty-four genes were reproducibly regulated by miR-205; eleven of them were annotated as cell junction- and tight junction-related molecules. Western blot analysis demonstrated that antagomir-induced silencing of miR-205 in primary cultured urothelial cells elevated the expression levels of Tjp1, Cgnl1, and Cdc42. Ectopic expression of miR-205 in MDCK cells inhibited the expression of tight junction proteins and the formation of tight junctions. miR-205- knockdown urothelial cells showed alterations in keratin synthesis and increases of uroplakin Ia and Ib, which are the urothelial differentiation products. These results suggest that miR-205 may contribute a role in regulation of urothelial differentiation by modulating the expression of tight junction-related molecules.

Generation of bladder urothelium from human pluripotent stem cells under chemically defined serum- and feeder-free system

Human stem cells are promising sources for bladder regeneration. Among several possible sources, pluripotent stem cells are the most fascinating because they can differentiate into any cell type, and proliferate limitlessly in vitro. Here, we developed a protocol for differentiation of human pluripotent stem cells (hPSCs) into bladder urothelial cells (BUCs) under a chemically defined culture system. We first differentiated hPSCs into definitive endoderm (DE), and further specified DE cells into BUCs by treating retinoic acid under a keratinocyte-specific serum free medium. hPSC-derived DE cells showed significantly expressed DE-specific genes, but did not express mesodermal or ectodermal genes. After DE cells were specified into BUCs, they notably expressed urothelium-specific genes such as UPIb, UPII, UPIIIa, P63 and CK7. Immunocytochemistry showed that BUCs expressed UPII, CK8/18 and P63 as well as tight junction molecules, E-CADHERIN and ZO-1. Additionally, hPSCs-derived BUCs exhibited low permeability in a FITC-dextran permeability assay, indicating BUCs possessed the functional units of barrier on their surfaces. However, BUCs did not express the marker genes of other endodermal lineage cells (intestine and liver) as well as mesodermal or ectodermal lineage cells. In summary, we sequentially differentiated hPSCs into DE and BUCs in a serum- and feeder-free condition. Our differentiation protocol will be useful for producing cells for bladder regeneration and studying normal and pathological development of the human bladder urothelium in vitro.

TLR4 mediates MAPK-STAT3 axis activation in bladder epithelial cells

The role of Toll-like receptor 4 (TLR4) in immune cells is well characterized, but its biological properties in bladder epithelial cells (BECs), especially reciprocal crosstalk between mitogen-activated protein (MAP) kinase pathway and signal transducer and activator of transcription (STAT)3-mediated signal transduction elicited by TLR4 have not been demonstrated so far. The present studies were to demonstrate the signal transduction and inflammatory cytokine response elicited through activation of TLR4 in BECs with a special focus on the crosstalk between the MAPK-pathway and STAT3-mediated signals and its regulatory relevance for the inflammatory response towards lipopolysaccharide (LPS). We selected human bladder cancer T24 cell line in the present study and examined its expression of TLR4 by reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry. The expression of p38, extracellular signal regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and STAT3 were performed by RT-PCR, quantitative PCR, and Western blotting. Signal transduction was analyzed by Western blotting. Interleukin-6 (IL-6) and interleukin-10 (IL-10) secretion in culture supernatants were tested by human enzyme-linked immunosorbent assay (ELISA) kit. BECs of rat infection in vivo model and patients with cystitis glandularis (CG) were analyzed as described above. Our study demonstrated that TLR4 was significantly upregulated following LPS treatment, with the maximum mRNA expression occurring at 4 h after stimulation. Activation of TLR4 signaling by LPS resulted in phosphorylation of MAPK and STAT pathways and upregulation of IL-10 in dose- and time-dependent manners in T24 cells. Pretreatment of cells with SB203580 (inhibitor of p38) and SP600125 (inhibitor of JNK) attenuated LPS-induced IL-10 expression, whereas it markedly inhibited the STAT3 expression. IL-10 mRNA expression was increased in inflamed lesions compared to noninflamed tissue in rats and patients with CG disease. Our results demonstrate that activation of TLR4 signaling in BECs induces IL-10 expression via activation of p38 and JNK, and the activation of STAT-3 was upregulated. Our data indicated that the reciprocal crosstalk between the MAPK pathway and STAT3-mediated signal transduction forms a critical axis successively activated by LPS in BECs.

Clonal, self-renewing and differentiating human and porcine urothelial cells, a novel stem cell population

Although urothelial progenitor-like cells have been described in the human urinary tract, the existence of stem cells remains to be proven. Using a culture system that favors clonogenic epithelial cell growth, we evaluated and characterized clonal human urothelial cells. We isolated human urothelial cells that were clonogenic, capable of self-renewal and could develop into fully differentiated urothelium once re-implanted into the subcapsular space of nude mice. In addition to final urothelial cell differentiation, spontaneous formation of bladder-like microstructures was observed. By examining an epithelial stem cell signature marker, we found p63 to correlate with the self-renewal capacity of the isolated human urothelial clonal populations. Since a clinically relevant, long-term model for functional reconstitution of human cells does not exist, we sought to establish a culture method for porcine urothelial cells in a clinically relevant porcine model. We isolated cells from porcine ureter, urethra and bladder that were clonogenic and capable of self-renewal and differentiation into fully mature urothelium. In conclusion, we could isolate human and porcine cell populations, behaving as urothelial stem cells and showing clonogenicity, self-renewal and, once re-implanted, morphological differentiation.