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Kirk M. Mchugh - One of the best experts on this subject based on the ideXlab platform.
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Roles for Urothelium in normal and aberrant urinary tract development
Nature Reviews Urology, 2020Co-Authors: Ashley R. Jackson, Christina B. Ching, Kirk M. Mchugh, Brian M BecknellAbstract:Congenital anomalies of the kidney and urinary tract (CAKUTs) represent the leading cause of chronic kidney disease and end-stage kidney disease in children. Increasing evidence points to critical roles for the Urothelium in the developing urinary tract and in the genesis of CAKUTs. The involvement of the Urothelium in patterning the urinary tract is supported by evidence that CAKUTs can arise as a result of abnormal urothelial development. Emerging evidence indicates that congenital urinary tract obstruction triggers urothelial remodelling that stabilizes the obstructed kidney and limits renal injury. Finally, the diagnostic potential of radiological findings and urinary biomarkers derived from the Urothelium of patients with CAKUTs might aid their contribution to clinical care. In this Review, Jackson and colleagues discuss the critical role of the Urothelium in both normal urinary tract development and in congenital abnormalities of the urinary tract. Urothelial remodelling in congenital obstructive uropathy is also discussed.
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Role of renal Urothelium in the development and progression of kidney disease
Pediatric Nephrology, 2017Co-Authors: Ashley R. Carpenter, Kirk M. MchughAbstract: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.
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uroplakin 1b is critical in urinary tract development and urothelial differentiation and homeostasis
Kidney International, 2016Co-Authors: Brian M Becknell, Edward J Cuaresma, David S Hains, Ashley R. Carpenter, Kirk M. Mchugh, Christina B. Ching, Xi ChenAbstract: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.
Ashley R. Carpenter - One of the best experts on this subject based on the ideXlab platform.
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Role of renal Urothelium in the development and progression of kidney disease
Pediatric Nephrology, 2017Co-Authors: Ashley R. Carpenter, Kirk M. MchughAbstract: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.
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uroplakin 1b is critical in urinary tract development and urothelial differentiation and homeostasis
Kidney International, 2016Co-Authors: Brian M Becknell, Edward J Cuaresma, David S Hains, Ashley R. Carpenter, Kirk M. Mchugh, Christina B. Ching, Xi ChenAbstract: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.
Baoxue Yang - One of the best experts on this subject based on the ideXlab platform.
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urea transporter ut b deletion induces dna damage and apoptosis in mouse bladder Urothelium
PLOS ONE, 2013Co-Authors: Zixun Dong, Jianhua Ran, Hong Zhou, Jihui Chen, Tianluo Lei, Weiling Wang, Yi Sun, Guiting Lin, Lise Bankir, Baoxue YangAbstract:Background Previous studies found that urea transporter UT-B is abundantly expressed in bladder Urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder Urothelium using UT-B knockout mouse model and T24 cell line.
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Urea Transporter UT-B Deletion Induces DNA Damage and Apoptosis in Mouse Bladder Urothelium
PLoS ONE, 2013Co-Authors: Zixun Dong, Jianhua Ran, Hong Zhou, Jihui Chen, Tianluo Lei, Weiling Wang, Yi Sun, Guiting Lin, Lise Bankir, Baoxue YangAbstract:Background: Previous studies found that urea transporter UT-B is abundantly expressed in bladder Urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder Urothelium using UT-B knockout mouse model and T24 cell line. Methodology/Principal Findings: Urea and NO measurement, mRNA expression micro-array analysis, light and transmission electron microscopy, apoptosis assays, DNA damage and repair determination, and intracellular signaling examination were performed in UT-B null bladders vs wild-type bladders and in vitro T24 epithelial cells. UT-B was highly expressed in mouse bladder Urothelium. The genes, Dcaf11, MCM2-4, Uch-L1, Bnip3 and 45 S pre rRNA, related to DNA damage and apoptosis were significantly regulated in UT-B null Urothelium. DNA damage and apoptosis highly occurred in UT-B null Urothelium. Urea and NO levels were significantly higher in UT-B null Urothelium than that in wild-type, which may affect L-arginine metabolism and the intracellular signals related to DNA damage and apoptosis. These findings were consistent with the in vitro study in T24 cells that, after urea loading, exhibited cell cycle delay and apoptosis. Conclusions/Significance: UT-B may play an important role in protecting bladder Urothelium by balancing intracellular urea concentration. Disruption of UT-B function induces DNA damage and apoptosis in bladder, which can result in bladder disorders.
Martin C. Michel - One of the best experts on this subject based on the ideXlab platform.
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Modulation of lower urinary tract smooth muscle contraction and relaxation by the Urothelium
Naunyn-Schmiedeberg's Archives of Pharmacology, 2018Co-Authors: Donna Sellers, Russ Chess-williams, Martin C. MichelAbstract:The epithelial inner layer of the lower urinary tract, i.e., the Urothelium, and other parts of the mucosa are not just a passive barrier but play an active role in the sensing of stretching, neurotransmitters, paracrine mediators, hormones, and growth factors and of changes in the extracellular environment. We review the molecular and cellular mechanisms enabling the Urothelium to sense such inputs and how this leads to modulation of smooth muscle contraction and relaxation. The Urothelium releases various mediators including ATP, acetylcholine, prostaglandins, nitric oxide, and nerve growth factor. These may affect function and growth of smooth muscle cells and afferent nerves. However, the molecular identity of the Urothelium-derived mediator directly modulating contractile and relaxant responses of isolated bladder strips has remained elusive. The morphology and function of the Urothelium undergo changes with aging and in many pathophysiological conditions. Therefore, the Urothelium may contribute to the therapeutic effects of established drugs to treat lower urinary tract dysfunction and may also serve as a target for novel therapeutics. However, therapeutics may also change urothelial function, and it is not always easy to determine whether such changes are part of the therapeutic response or reflect secondary alterations.
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Expression profiling of G-protein-coupled receptors in human Urothelium and related cell lines.
BJUI, 2012Co-Authors: Peter Ochodnický, Sian Humphreys, Rachel Eccles, Mirjana Poljakovic, Peter Wiklund, Martin C. MichelAbstract:What's known on the subject? and What does the study add? Urothelium emerged as a crucial integrator of sensory inputs and outputs in the bladder wall, and urothelial G-protein-coupled receptors (GPCRs) may represent plausible targets for treatment of various bladder pathologies. Urothelial cell lines provide a useful tool to study urothelial receptor function, but their validity as models for native human Urothelium remains unclear. We characterize the mRNA expression of genes coding for GPCRs in human freshly isolated Urothelium and compare the expression pattern with those in human urothelial cell lines. OBJECTIVES • To characterize the mRNA expression pattern of genes coding for G-protein-coupled receptors (GPCRs) in human freshly isolated Urothelium. • To compare GPCR expression in human Urothelium-derived cell lines to explore the suitability of these cell lines as model systems to study urothelial function. MATERIALS AND METHODS • Native human Urothelium (commercially sourced) and human Urothelium-derived non-cancer (UROtsa and TERT-NHUC) and cancer (J82) cell lines were used. • For mRNA expression profiling we used custom-designed real-time polymerase chain reaction array for 40 receptors and several related genes. RESULTS • Native Urothelium expressed a wide variety of GPCRs, including α1A, α1D and all subtypes of α2 and β adrenoceptors. In addition, M2 and M3 cholinergic muscarinic receptors, angiotensin II AT1 receptor, serotonin 5-HT2A receptor and all subtypes of bradykinin, endothelin, cannabinoid, tachykinin and sphingosine-1-phosphate receptors were detected. Nerve growth factor and both its low- and high-affinity receptors were also expressed in Urothelium. • In all cell lines expression of most GPCRs was markedly downregulated, with few exceptions. • In UROtsa cells, but much less in other cell lines, the expression of β2 adrenoceptors, M3 muscarinic receptors, B1 and B2 bradykinin receptors, ETB endothelin receptors and several subtypes of sphingosine-1-phosphate receptors was largely retained. CONCLUSIONS • Human Urothelium expresses a wide range of receptors which enables sensing and integration of various extracellular signals. • Human Urothelium-derived cell lines, especially UROtsa cells, show comparable mRNA expression to native tissue for several physiologically relevant GPCRs, but lose expression of many other receptors. • The use of cell lines as model systems of human Urothelium requires careful validation of suitability for the genes of interest.
Jennifer Southgate - One of the best experts on this subject based on the ideXlab platform.
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Nocturnal enuresis—investigating the possible role of water transfer across the Urothelium by looking for the presence of vasopressin receptors and aquaporins in Urothelium
Archives of Disease in Childhood, 2010Co-Authors: Peter Rubenwolf, P Holland, Nikolaos T. Georgopoulos, Lisa A. Clements, Sally Feather, David Terence Thomas, Jennifer SouthgateAbstract:Aims To test the hypothesis that vasopressin-sensitive aquaporin 2 (AQP2) may be present in the human Urothelium and contribute towards obtaining night time continence. Background In studies comparing dry and wet nights in children with enuresis it was hypothesised that there may be water transfer across the Urothelium overnight resulting in an increase in urine concentration and a reduction in urine volume. The authors postulated that human Urothelium would have to express the vasopressin receptor and AQP2. Methods Using previously evaluated techniques, human Urothelium was isolated and used to prepare messenger RNA, perform immunohistological studies and to establish finite NHU cell lines. All samples were then studied for expression of vasopressin receptor and aquaporins 0–12. Results Native and cultured urothelia were negative for vasopressin receptor and AQP2 transcripts, whereas transcripts for aquaporins 3, 4, 7, 9 and 11 were detected. Immunohistochemistry revealed human Urothelium to be intensely positive for AQP3 in the basal and intermediate layers of the Urothelium, localising to intercellular borders. AQP 4 and 7 showed less intense cytoplasmic expression throughout the Urothelium. No immunoreactivity was found for AQP 9. Conclusion The original hypothesis that water transfer might occur across human Urothelium due to the presence of vasopressin-sensitive AQP2 is incorrect. The detection of AQP 3 and 4 raises the possibility that water and urea transfer may occur across the Urothelium. However, it is yet to be determined whether these proteins contribute to urinary continence mechanisms.
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S05: Effects of PPAR agonists on proliferation and differentiation in the Urothelium
Experimental and Toxicologic Pathology, 2009Co-Authors: L Varley Claire, Jennifer SouthgateAbstract:Systemic treatment of rats with PPAR agonists (mainly of dual α/γ activity) has indicated that they may invoke non-genotoxic carcinogenesis in the epithelial lining of the urinary tract (Urothelium). Although there is evidence in the male rat to support an indirect effect via a crystaluria-induced urothelial damage response (Cohen SM, Toxicological Sciences 2005; 87 (2): 322–7), there is other evidence to indicate a direct signalling effect on the Urothelium (Egerod FL, Nielsen HS, Iversen L, et al., Biomarkers 2005; 10 (4): 295–309) and hence the full implications for using these drugs in man is unclear. Numerous reports have demonstrated that PPARs are expressed within the Urothelium of different species, including man, and from an early developmental stage. We have developed methods to maintain normal human urothelial (NHU) cells in culture, where the cells retain PPAR expression and express a highly proliferative phenotype, mediated via autocrine stimulation of the epidermal growth factor receptor (EGFR). We have shown that specific activation of PPARγ will result in a programme of gene expression changes associated with late/terminal cytodifferentiation, including induction of cytokeratins CK13 and CK20, tight junction-associated claudin 3 and uroplakins UPK1a and UPK2, but this is dependent upon inhibition of the signalling cascade downstream of EGFR. This indicates a subtle balance in the regulation of proliferation and differentiation in Urothelium, with PPARγ agonists promoting differentiation. Our data indicates that human Urothelium is a target tissue for PPARγ signalling, but it has yet to be determined whether dual agonists could have a modulatory effect on the proliferative/differentiation balance.
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Regulation and Function of Aquaporins in Human Urothelium
Journal of Pediatric Urology, 2009Co-Authors: Peter Rubenwolf, Sally Feather, Philip Holland, David F.m. Thomas, Jennifer SouthgateAbstract:PURPOSE We have previously provided molecular evidence that aquaporins (AQP) are expressed by human Urothelium, suggesting a potential role in water and solute transport (Rubenwolf et al, 2008). The aim of this work was to investigate factors that regulate AQP expression in human Urothelium and to develop functional assays to examine the potential role in urothelial physiology. MATERIAL AND METHODS Normal Human Urothelial (NHU) cell lines were established and the effect on AQP protein expression of exposing NHU cell cultures to osmotic stress was examined by immunochemistry. The barrier properties of differentiated urothelial constructs were assessed by measuring transepithelial electrical resistance (TER) and permeability coefficients for 3H water and 14C urea. HgCl2 was used as a non-competitive AQP channel blocker. RESULTS AQP 3 protein expression was shown to be up-regulated by up to 13-fold in response to changing the culture medium osmolality from 295 to 500 mosm/kg. Differentiated Urothelium revealed a significant barrier function (average TER: 3680 Ω.cm 2 ); average diffusive water and urea permeability coefficients (Pd) were 10.4x10-5 and 3.7x10-5 cm/sec, respectively. Mean osmotic permeability coefficients (Posm) were 1.8-fold higher than corresponding diffusive permeability coefficients. A significant, dose-dependent (up to 4-fold) decrease of both water and urea flux across Urothelium was observed upon application of HgCl2. CONCLUSIONS Our results demonstrate for the first time that expression of AQP 3 is regulated by osmolality, which suggests that Urothelium is capable of reabsorbing water in response to the body's hydration status. The low, but finite, permeability of cultured Urothelium to water and urea, which was reduced upon AQP inhibition, is also highly supportive of a previously unrecognised role for AQPs in body fluid regulation with potential implications on urinary tract physiology and urinary continence.
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Expression and localisation of aquaporin water channels in human Urothelium in situ and in vitro.
European Urology, 2008Co-Authors: Peter Rubenwolf, Nikolaos T. Georgopoulos, Lisa A. Clements, Sally Feather, Philip Holland, David F.m. Thomas, Jennifer SouthgateAbstract:Abstract Background Urothelium is generally considered to be impermeable to water and constituents of urine. The possibility that human Urothelium expresses aquaporin (AQP) water channels as the basis for water and solute transport has not previously been investigated. Objective To investigate the expression of AQP water channels by human Urothelium in situ, in proliferating urothelial cell cultures and in differentiated tissue constructs. Design, setting, and participants AQP expression by human Urothelium in situ and cultured urothelial cells was assessed by reverse transcriptase–polymerase chain reaction (RT-PCR) and immunolabelling. Expression screening was carried out on samples of freshly isolated urothelia from multiple surgical (bladder and ureteric) specimens and on proliferating and differentiated normal human urothelial (NHU) cells in culture. Urothelial tissue constructs were established and investigated for expression of urothelial differentiation markers and AQPs. Measurements Qualitative study. Results and limitations Transcripts for AQP3, AQP4, AQP7, AQP9, and AQP11 were expressed consistently by freshly isolated urothelia as well as by cultured NHU cells. AQP0, AQP1, AQP2, AQP5, AQP6, AQP8, AQP10, and AQP12 were not expressed. Immunochemistry confirmed expression of AQP3, AQP4, AQP7, and AQP9 at the protein level. AQP3 was shown to be intensely expressed at cell borders in the basal and intermediate layers in both Urothelium in situ and differentiated tissue constructs in vitro. Conclusions This is the first study to demonstrate that AQPs are expressed by human Urothelium, suggesting a potential role in transurothelial water and solute transport. Our findings challenge the traditional concept of the urinary tract as an impermeable transit and storage unit and provide a versatile platform for further investigations into the biological and clinical relevance of AQPs in human Urothelium.
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Effects of PPAR agonists on proliferation and differentiation in human Urothelium.
Experimental and Toxicologic Pathology, 2008Co-Authors: Claire L. Varley, Jennifer SouthgateAbstract:Systemic treatment of rats with peroxisome proliferator-activated receptor (PPAR) agonists (mainly of dual alpha/gamma activity) has indicated that they may invoke non-genotoxic carcinogenesis in the epithelial lining of the urinary tract (Urothelium). Although there is evidence in the male rat to support an indirect effect via a crystaluria-induced urothelial damage response, there is other evidence to indicate a direct signalling effect on the Urothelium and hence the full implication for using these drugs in man is unclear. Numerous reports have demonstrated that PPARs are expressed within the Urothelium of different species, including man, and from an early developmental stage. We have developed methods to maintain normal human urothelial (NHU) cells in culture, where the cells retain PPAR expression and express a highly proliferative phenotype, mediated via autocrine stimulation of the epidermal growth factor (EGF) receptor. We have shown that specific activation of PPARgamma results in a programme of gene expression changes associated with late/terminal cytodifferentiation, including induction of cytokeratins CK13 and CK20, tight junction-associated claudin 3, and uroplakins UPK1a and UPK2, but this is dependent upon inhibition of the signalling cascade downstream of the EGF receptor. This indicates a subtle balance in the regulation of proliferation and differentiation in Urothelium, with PPARgamma agonists promoting differentiation. Our data indicate that human Urothelium is a target tissue for PPARgamma signalling, but it has yet to be determined whether dual agonists could have a modulatory effect on the proliferation/differentiation balance.
