High Hydrostatic Pressure Exacerbates Bladder Fibrosis through Activating Piezo1.

OBJECTIVE: Bladder outlet obstruction (BOO) results in significant fibrosis in the chronic stage and elevated bladder pressure. Piezo1 is a type of mechanosensitive (MS) channel that directly responds to mechanical stimuli. To identify new targets for intervention in the treatment of BOO-induced fibrosis, this study investigated the impact of high hydrostatic pressure (HHP) on Piezo1 activity and the progression of bladder fibrosis. METHODS: Immunofluorescence staining was conducted to assess the protein abundance of Piezo1 in fibroblasts from obstructed rat bladders. Bladder fibroblasts were cultured under normal atmospheric conditions (0 cmH2O) or exposed to HHP (50 cmH2O or 100 cmH2O). Agonists or inhibitors of Piezo1, YAP1, and ROCK1 were used to determine the underlying mechanism. RESULTS: The Piezo1 protein levels in fibroblasts from the obstructed bladder exhibited an elevation compared to the control group. HHP significantly promoted the expression of various pro-fibrotic factors and induced proliferation of fibroblasts. Additionally, the protein expression levels of Piezo1, YAP1, ROCK1 were elevated, and calcium influx was increased as the pressure increased. These effects were attenuated by the Piezo1 inhibitor Dooku1. The Piezo1 activator Yoda1 induced the expression of pro-fibrotic factors and the proliferation of fibroblasts, and elevated the protein levels of YAP1 and ROCK1 under normal atmospheric conditions in vitro. However, these effects could be partially inhibited by YAP1 or ROCK inhibitors. CONCLUSION: The study suggests that HHP may exacerbate bladder fibrosis through activating Piezo1.

Comparative RNA-sequencing analysis of the prostate in a mouse model of benign prostatic hyperplasia with bladder outlet obstruction.

In ageing men, benign prostatic hyperplasia (BPH) is a chronic disease that leads to progressive lower urinary tract symptoms (LUTS) caused by obstruction of the bladder outlet (BOO). Patients with LUTS (such as increased frequency and urgency of urination) and complications of BOO (such as hydronephrosis and bladder stones) are at risk of serious health problems. BPH causes a rapidly rising burden of LUTS far exceeding that of other urological conditions. Treatment outcomes are unsatisfactory for BPH largely due to the lacking of fully understanding of the pathogenesis. Hormonal imbalances related to androgen and oestrogen can cause BPH, but the exact mechanism is still unknown, even the animal model is not fully understood. Additionally, there are no large-scale data to explain this mechanism. A BPH mouse model was established using mixed slow-release pellets of testosterone (T) and estradiol (E2), and we measured gene expression in mouse prostate tissue using RNA-seq, verified the results using qRT‒PCR, and used bioinformatics methods to analyse the differentially expressed genes (DEGs).

Molecular Characterization of Non-Neurogenic and Neurogenic Lower Urinary Tract Dysfunction (LUTD) in SCI-Induced and Partial Bladder Outlet Obstruction Mouse Models.

We examined bladder function following spinal cord injury (SCI) by repeated urodynamic investigation (UDI), including external urethral sphincter (EUS) electromyography (EMG) in awake restrained mice and correlated micturition parameters to gene expression and morphological changes in the bladder. A partial bladder outlet obstruction (pBOO) model was used for comparison to elucidate both the common and specific features of obstructive and neurogenic lower urinary tract dysfunction (LUTD). Thirty female C57Bl/6J mice in each group received an implanted bladder catheter with additional electrodes placed next to the EUS in the SCI group. UDI assessments were performed weekly for 7 weeks (pBOO group) or 8 weeks (SCI group), after which bladders were harvested for histological and transcriptome analysis. SCI mice developed detrusor sphincter dyssynergia (DSD) one week after injury with high-pressure oscillations and a significantly increased maximal bladder pressure Pmax and were unable to void spontaneously during the whole observation period. They showed an increased bladder-to-bodyweight ratio, bladder fibrosis, and transcriptome changes indicative of extracellular matrix remodeling and alterations of neuronal signaling and muscle contraction. In contrast, pBOO led to a significantly increased Pmax after one week, which normalized at later time points. Increased bladder-to-bodyweight ratio and pronounced gene expression changes involving immune and inflammatory pathways were observed 7 weeks after pBOO. Comparative transcriptome analysis of SCI and pBOO bladders revealed the activation of Wnt and TGF-beta signaling in both the neurogenic and obstructive LUTD and highlighted FGF2 as a major upregulated transcription factor during organ remodeling. We conclude that SCI-induced DSD in mice leads to profound changes in neuronal signaling and muscle contractility, leading to bladder fibrosis. In a similar time frame, significant bladder remodeling following pBOO allowed for functional compensation, preserving normal micturition parameters.

Exosomes from human urine-derived stem cells carry NRF1 to alleviate bladder fibrosis via regulating miR-301b-3p/TGFßR1 pathway.

Bladder outlet obstruction (BOO) is a common disease that always make the bladder develops from inflammation to fibrosis. This study was to investigate the effect of exosomes from human urine-derived stem cells (hUSCs) on bladder fibrosis after BOO and the underlying mechanism. The BOO mouse model was established by inserting a transurethral catheter, ligation of periurethral wire, and removal of the catheter. Mouse primary bladder smooth muscle cells (BSMCs) were isolated and treated with TGFß1 to mimic the bladder fibrosis model in vitro. Exosomes from hUSCs (hUSC-Exos) were injected into the bladder of BOO mice and added into the culture of TGFß1-induced BSMCs. The associated factors in mouse bladder tissues and BSMCs were detected. It was confirmed that the treatment of hUSC-Exos alleviated mouse bladder fibrosis and down-regulated fibrotic markers (a-SMA and collagen III) in bladder tissues and TGFß1-induced BSMCs. Overexpression of NRF1 in hUSC-Exos further improved the effects of hUSC-Exos on bladder fibrosis both in vivo and in vitro. TGFßR1 was a target of NRF1 and miR-301b-3p, and miR-301b-3p was a target of NRF1. It was next characterized that hUSC-Exos carried NRF1 to up-regulate miR-301B-3p, thereby reducing TGFßR1level. Our results illustrated that hUSC-Exos carried NRF1 to alleviate bladder fibrosis through regulating miR-301b-3p/TGFßR1 pathway.

Changes of proapoptotic and antiapoptotic genes affect sensitivity to apoptotic stimuli in impaired contractility due to long term bladder outlet obstruction.

INTRODUCTION: The normal biological process that necessitates cell removal greatly depends on apoptosis. Long term bladder outlet obstruction (BOO) causes damaged smooth muscle cells to undergo apoptosis. However, smooth muscle cell apoptosis that BOO causes is not well known in impaired bladder contractility. Therefore, we designed this study to investigate whether long-term BOO could induce apoptosis activities and to obtain an expression profile of apoptosis related genes. MATERIALS AND METHODS: We used 10 Sprague-Dawley six-week-old female rats. We separated them equally into two groups: a sham intervention group (group 1) and an eight-week BOO group (group 2). We conducted cystometric evaluation eight weeks following BOO onset, with processing of bladder tissue for PCR array. Every array comprised 84 genes, which were established to contribute to an apoptosis response, cell differentiation and metabolism, and 12 sequences were established for the regulation of loading and the quality of cDNA. We performed real-time PCR. Changes in gene expression presented as a fold increase/decrease. Alterations of more than two-fold constituted the cut-off determining expression. RESULTS: Group 2 had a greater bladder weight and Impaired bladder contractility. Immunofluorescent staining with CAS3, TUNEL showed increased in the BOO group. In comparison to group 1, group 2 exhibited an at least two-fold upregulation in five genes, the Bcl-2 (15.1), Birc5 (5.8), Cd40lg (7.5), Il10 (16.2), and Naip2 (13.2). They also demonstrated at least a two-fold downregulation in the PRLR (-18.1) gene. Genes Bcl2ald, Circ5, Cd40lg, Il10, Naip2, and PRLR were among the genes with activity against apoptosis. TNF, STAT3 and TP53 mediated the effect that genes had on one another. CONCLUSION: This study demonstrated that the relative ratios of pro- and antiapoptotic genes determine bladder cell sensitivity cells to apoptotic stimuli in impaired contractility caused by long term BOO. Although we cannot confirm whether this finding is the result of the decompensated phase of the bladder or the process, the gene expression profiles could explain molecular mechanisms of apoptosis in impaired bladder contractility caused by long-term BOO with further studies.

CircRNA/miRNA/mRNA axis participates in the progression of partial bladder outlet obstruction.

BACKGROUND: More and more evidence showed that circRNA/miRNA/mRNA axis played a vital role in the pathogenesis of some diseases. However, the role of circRNA/miRNA/mRNA axis in partial bladder outlet obstruction (pBOO) remains unknown. Our study aimed to explore the complex regulatory mechanism of circRNA/miRNA/mRNA axis in pBOO. METHODS: The pBOO rat model was established, and the bladder tissues were collected for mRNA sequencing. The differentially expressed mRNAs were analyzed by high-throughput sequencing, and the GO and KEGG analysis of the differentially expressed mRNAs were performed. Competing endogenous RNAs (ceRNAs) analysis identified the potential regulation function of circRNA/miRNA/mRNA axis in pBOO. qRT-PCR detected the expression of circRNA/miRNA/mRNA. miRanda software was performed to predict the relationship between circRNA and miRNA, miRNA and mRNA. RESULTS: Compared with the sham group, a total of 571 mRNAs were differentially expressed in the pBOO group, of which 286 were up-regulated and 285 were down-regulated. GO analysis showed that the mRNAs were mainly involved in cellular process, single-organism process, and cell, etc. KEGG analysis showed that the enriched signaling pathways were metabolic pathways, cell adhesion molecules (CAMs), and HTLV-I infection, etc. Based on the previous transcriptome data and differentially expressed circRNAs, we drew the ceRNA network regulation diagram. qRT-PCR results confirmed that chr3:113195876|113197193/rno-miR-30c-1-3p/Gata4, chr1:126188351|126195625/rno-miR-153-5p/Diaph3, and chr9:81258380|81275269/rno-miR-135b-5p/Pigr axis may have ceRNA function. miRanda confirmed there have the binding sites of circRNA/miRNA/mRNA axis. CONCLUSIONS: CircRNA/miRNA/mRNA axis was involved in the progression of pBOO. Our research on the circRNA/miRNA/mRNA axis revealed new pathogenesis and treatment strategies for pBOO.

Molecular and Morphological Characteristics of the De-Obstructed Rat Urinary Bladder-An Update.

Many patients with outlet obstruction secondary to prostatic enlargement have lower urinary tract symptoms (LUTSs) and an increased frequency of micturition. The standard treatment is transurethral resection of the prostate (TURP), which alleviates obstruction and symptoms. However, after TURP, 20-40 percent of patients continue to experience LUTSs. The aim of the present study in rats was to identify the mechanisms that do not normalize after the removal of the obstruction and that could explain the persisting symptoms. We had microarray data from control, obstructed, and de-obstructed female rat bladders, which made it possible to study 14,553 mRNA expressions. We also had a bank of electron micrographs from similar detrusors. Microarrays: There were significant differences between the control and obstructed bladders for 1111 mRNAs. The obstructed and de-obstructed bladders differed significantly for 1059 mRNAs. The controls and the de-obstructed bladders differed significantly for 798 mRNAs. We observed many mRNAs that were increased in the obstructed bladder and then decreased to control levels after de-obstruction, and many mRNAs that were decreased in the obstructed bladder and then increased following de-obstruction. mRNAs that were significantly higher or lower in the de-obstructed bladder than in the control bladder were also found. Ultrastructure: The detrusor cells in the obstructed bladders had cross-sectional areas that were much larger than those in the controls. The control cells had smooth outlines and similar cross-sectional areas. The de-obstructed detrusor cells had larger cross-sectional areas than the controls, as well as corrugated surfaces. The cell areas varied, suggesting that the shrinkage of the de-obstructed cells was not even. We did not find any points of contact of the gap junction plaque type between the detrusor cells. There were abundant finger-like processes between the detrusor cells in the obstructed and in de-obstructed bladders, which were only occasionally found in the control detrusors. They are the only possible localization for gap junction channels. The de-obstructed rat bladder is not an organ with properties intermediate between those of the control and obstructed bladders. Instead, de-obstructed bladders have gene expressions, morphologies, and functional properties of the individual cells and their organization, which make them distinctly different from both control and obstructed bladders.

Human amniotic fluid stem cells can alleviate detrusor dysfunction caused by bladder outlet obstruction in rats.

The present study examined whether bladder detrusor dysfunction due to partial bladder outlet obstruction (pBOO) could be improved after the treatment of human amniotic fluid stem cells (hAFSCs). 72 female rats were grouped into sham operation, pBOO, and pBOO with hAFSCs treatment (pBOO + hAFSCs) for in vitro and in vivo studies. Bladder weight, bladder wall thickness, the ratio of collagen to smooth muscle and the levels of positive CD11b/c and HIS48 cells was significantly increased after pBOO but improved after hAFSCs treatment. Cystometries showed impaired bladder function after pBOO. Protein and mRNA levels of hypoxia inducible factor-1α, CCL2, interleukin-1ß, transforming growth factor-ß1 (TGF-ß1), connective tissue growth factor (CTGF), α-smooth muscle actin, collagen I and collagen III were increased at 2 and/or 6 weeks, but proteins and mRNA expressions of protein gene product 9.5 were decreased at 2 and 6 weeks after pBOO. These abnormalities were improved after hAFSCs treatment. The expressions of TGF-ß1 and CTGF in cultured detrusor cells of pBOO rats were increased but were improved after hAFSCs treatment. The present results showed hAFSCs treatment could improve bladder detrusor dysfunction in pBOO rats, which may be related to the reduction of inflammatory and pro-fibrotic markers in detrusor muscle cells.

Enhanced Hypoxia-Associated Genes in Impaired Contractility From Bladder Outlet Obstruction.

BACKGROUND: Hypoxia damages the bladder wall and contributes to the initiation of bladder dysfunction. The change of hypoxia is not well known in impaired bladder contractility caused by long-term bladder outlet obstruction (BOO). We aimed to find out whether hypoxia of bladder tissue is present and what signaling mechanisms are involved in the decompensated bladder in BOO. METHODS: Twenty 6-week-old female Sprague-Dawley rats were divided into 2 groups, 10 rats each: group 1, sham operation; group 2, BOO for 8 weeks. Eight weeks after the onset of BOO, we did cystometric evaluation and processed polymerase chain reaction (PCR) array for hypoxia pathway using bladder tissues. The PCR array consists of 84 genes known to be involved in the hypoxic response, cell differentiation, and metabolism. We did quantitative PCR (qPCR) and immunohistochemical staining of bladder tissue for hypoxia. RESULTS: Eight genes were at least 2-fold upregulated and 3 genes were at least 2-fold downregulated in BOO group, compared with the sham operation group. The up-regulated genes (fold change) belonging to the hypoxia-inducible factor (HIF) 1 interactor included Cdkn2a (11.0), and the down-regulated genes belonging to HIF and co-transcription factors included Hif3a (-39.6) and Per1 (-5.1) by BOO. Genes influenced each other by means of TGFß1, TNF, and TP53. CONCLUSION: Hypoxia genes were increased in impaired contractility because of long-term BOO. The gene expression profiles could explain the molecular mechanisms of hypoxia in impaired contractility because of long-term BOO.

Human Urine-Derived Stem Cells Improve Partial Bladder Outlet Obstruction in Rats: Preliminary Data and microRNA-mRNA Expression Profile.

Partial bladder outlet obstruction (pBOO) often results in bladder tissue inflammation and remodeling. As human urine-derived stem cells (USCs) have demonstrated therapeutic benefits, we used a rat model to investigate the effect of USCs on bladder function and explore the miRNA and gene expression profiles in bladder tissue using RNA sequencing. Eighteen rats were assigned to a sham surgery group, pBOO group, and pBOO+USC group (six biweekly treatments). Routine urodynamic monitoring, analysis of detrusor muscle strips, and pathophysiology assessments were conducted. Finally, altered miRNA and mRNA expression profiles of bladder tissue were examined using RNA sequencing and bioinformatics analysis. After USC treatment, elevated bladder compliance and maximal voiding pressure, declined end filling pressure and voided volume, and improved detrusor muscle contractility and carbachol sensitivity were found. Histology and TUNEL assay revealed reduced collagen deposition and muscle cell apoptosis in bladder tissue. The differential expression of eight miRNAs was reversed by USC treatment. Two large nodes (miR-142 and miR-9a) were identified in the miRNA-gene interaction network in the USC-treated group. The Kyoto Encyclopedia of Genes and Genomes analysis revealed enrichment of multiple significant pathways, including those involved in necroptosis and cytokine-cytokine receptor interactions. This is the first study to demonstrate the protective effect of USCs on bladder function and remodeling in pBOO rats. The miRNA and mRNA expression levels differed in the bladder of pBOO rats with and without USC treatment. Although the mechanism underlying these effects has not been fully elucidated, necroptosis and cytokine-cytokine receptor interaction-related pathways may be involved.

Serum/glucocorticoid-regulated kinase 1-targeted transient receptor potential oxalate subtype 1 regulates bladder smooth muscle cell proliferation due to bladder outlet obstruction in mice via activated T cell nuclear factor transcription factor 2.

Bladder outlet obstruction (BOO) is a type of chronic disease that is mainly caused by benign prostatic hyperplasia. Previous studies discovered the involvements of both serum/glucocorticoid-regulated kinase 1 (SGK1) and activated T cell nuclear factor transcription factor 2 (NFAT2) in the proliferation of smooth muscle cells after BOO. However, the relationship between these two molecules is yet to be explored. Thus, this study explored the specific mechanism of the SGK1-NFAT2 signaling pathway in mouse BOO-mediated bladder smooth muscle cell proliferation in vivo and in vitro. In vivo experiments were performed by suturing 1/2 of the external urethra of female BALB/C mice to cause BOO for 2 weeks. In vitro, mouse bladder smooth muscle cells (MBSMCs) were treated with dexamethasone (Dex) or dexamethasone + SB705498 for 12 h and were transfected with SGK1 siRNA for 48 h. The expression and distribution of SGK1, transient receptor potential oxalate subtype 1 (TRPV1), NFAT2, and proliferating cell nuclear antigen (PCNA) were measured by Western blotting, polymerase chain reaction, and immunohistochemistry. The relationship between SGK1 and TRPV1 was analyzed by coimmunoprecipitation. The proliferation of MBSMCs was examined by 5-ethynyl-2'-deoxyuridine and cell counting kit 8 assays. Bladder weight, smooth muscle thickness, and collagen deposition in mice after 2 weeks of BOO were examined. Bladder weight, smooth muscle thickness, the collagen deposition ratio, and the expression of SGK1, TRPV1, NFAT2, and PCNA were significantly increased in mice after 2 weeks of BOO. Compared with the control, 10 µM Dex promoted the expression of these four molecules and the proliferation of MBSMCs. After inhibiting TRPV1, only the expression of SGK1 was not affected, and the proliferation of MBSMCs was inhibited. After silencing SGK1, the expression of these four molecules and the proliferation of MBSMCs decreased. Coimmunoprecipitation suggested that SGK1 acted directly on TRPV1. In this study, SGK1 targeted TRPV1 to regulate the proliferation of MBSMCs mediated by BOO in mice through NFAT2 and then affected the process of bladder remodeling after BOO. This finding may provide a strategy for BOO drug target screening.

Circular RNA Plasmacytoma Variant Translocation 1 (CircPVT1) knockdown ameliorates hypoxia-induced bladder fibrosis by regulating the miR-203/Suppressor of Cytokine Signaling 3 (SOCS3) signaling axis.

The effects of circular RNAs (circRNAs) on bladder outlet obstruction (BOO)-induced hypertrophy and fibrogenesis in rats and hypoxia-induced bladder smooth muscle cell (BSMC) fibrosis remain unclear. This study aimed to determine the regulatory role of circRNAs in the phenotypic changes in BSMCs in BOO-induced rats.circRNAmicroarray and real-time PCR were used to explore differentiated expressed circRNAs. Bioinformatics analyses and dual-luciferase reporter were performed to identify the targets for circRNA PVT1 (circPVT1). BOO was performed to establish a bladder fibrosis animal model. The circPVT1 and suppressor of cytokine signaling 3 (SOCS3) expression levels were upregulated (p = 0.0061 and 0.0328, respectively), whereas the microRNA-203a (miR-203) level was downregulated in rats with bladder remodeling (p=0.0085). Bioinformatics analyses and dual-luciferase reporter assay results confirmed that circPVT1 sponges miR-203 and that the latter targets the 3'-untranslated region of SOCS3. Additionally, circPVT1 knockdown alleviated BOO-induced bladder hypertrophy and fibrogenesis. Furthermore, hypoxia was induced in BSMCs to establish a cell model of bladder fibrosis. Hypoxia induction in BSMCs resulted in upregulated circPVT1 and SOCS3 levels (p = 0.0052) and downregulated miR-203 levels. Transfection with circPVT1 and SOCS3 shRNA ameliorated hypoxia-induced transforming growth factor-ß (TGF-ß1), TGFßR1, α-smooth muscle actin, fibrotic growth factor, extracellular matrix subtypes, BSMC proliferation, and apoptosis-associated cell injury, whereas co-transfection with miR-203 inhibitor counteracted the effect of circPVT1 shRNA on these phenotypes.These findings revealed a novel circRNA regulator of BOO-associated bladder wall remodeling and hypoxia-induced phenotypic changes in BMSCs by targeting the miR-203-SOCS3 signaling axis.

Increased transient receptor potential canonical 3 activity is involved in the pathogenesis of detrusor overactivity by dynamic interaction with Na+/Ca2+ exchanger 1.

Transient receptor potential canonical 3 (TRPC3) is a nonselective cation channel, and its dysfunction is the basis of many clinical diseases. However, little is known about its possible role in the bladder. The purpose of this study was to explore the function and mechanism of TRPC3 in partial bladder outlet obstruction (PBOO)-induced detrusor overactivity (DO). We studied 31 adult female rats with DO induced by PBOO (the DO group) and 40 sham-operated rats (the control group). Here we report that the expression of TRPC3 in the bladder of DO rats increased significantly. Furthermore, PYR10, which can selectively inhibit the TRPC3 channel, significantly reduced bladder excitability in DO and control rats, but the decrease of the bladder excitability of DO rats was more obvious. PYR10 significantly reduced the intracellular calcium concentration in smooth muscle cells (SMCs) in DO and control rats. Finally, Na+/Ca2+ exchanger 1 (NCX1) colocalizes with TRPC3 and affects its expression and function. Collectively, these results indicate that TRPC3 plays an important role in the pathogenesis of DO through a synergistic effect with NCX1. TRPC3 and NCX1 may be new therapeutic targets for DO.

Genome-Wide Survey for Microdeletions or -Duplications in 155 Patients with Lower Urinary Tract Obstructions (LUTO).

Lower urinary tract obstruction (LUTO) is, in most cases, caused by anatomical blockage of the bladder outlet. The most common form are posterior urethral valves (PUVs), a male-limited phenotype. Here, we surveyed the genome of 155 LUTO patients to identify disease-causing CNVs. Raw intensity data were collected for CNVs detected in LUTO patients and 4.392 healthy controls using CNVPartition, QuantiSNP and PennCNV. Overlapping CNVs between patients and controls were discarded. Additional filtering implicated CNV frequency in the database of genomic variants, gene content and final visual inspection detecting 37 ultra-rare CNVs. After, prioritization qPCR analysis confirmed 3 microduplications, all detected in PUV patients. One microduplication (5q23.2) occurred de novo in the two remaining microduplications found on chromosome 1p36.21 and 10q23.31. Parental DNA was not available for segregation analysis. All three duplications comprised 11 coding genes: four human specific lncRNA and one microRNA. Three coding genes (FBLIM1, SLC16A12, SNCAIP) and the microRNA MIR107 have previously been shown to be expressed in the developing urinary tract of mouse embryos. We propose that duplications, rare or de novo, contribute to PUV formation, a male-limited phenotype.

Partial inhibition of activin receptor-like kinase 4 alleviates bladder fibrosis caused by bladder outlet obstruction.

The bladder undergoes profound structural alterations after bladder outlet obstruction (BOO), characterized by hypertrophy of the bladder wall and accumulation of extracellular matrix (ECM). Transforming growth factor-ß (TGF-ß) has been found to promote fibrosis of the bladder induced by partial bladder outlet obstruction (pBOO). Activin receptor-like kinase 4 (ALK4) is a downstream receptor of the TGF-ß superfamily. However, the role of the ALK4-Smad2/3 pathway in the pathogenesis of bladder fibrosis caused by pBOO remains unknown. This study focused on learning the role of ALK4 in the process of bladder fibrosis caused by pBOO. The pBOO mice models showed that ALK4 expression was found to upregulate in the wild-type bladder 6 weeks after pBOO compared to control group. Then, mice with heterozygous knockout of the ALK4 gene (ALK4+/-) were generated. Histological analysis and Western blot (WB) results showed significant suppression of collagen expression in the bladders of ALK4+/- mice after pBOO compared with WT mice. WB also showed that ALK4+/- mice demonstrated significant suppression of phosphorylated Smad2/3 (p-Smad2/3) expression in the bladder 6 weeks after pBOO but not of phosphorylated extracellular signal-regulated kinase, c-Jun N-terminal kinase or protein 38 (p-ERK, p-JNK, p-P38) expression. This effect might have occurred through partial inactivation of the Smad2/3 signaling pathway. In vitro, ALK4 overexpression promoted collagen production in cultured BSMCs and activated the Smad2/3 signaling pathway. Taken together, our results demonstrated that ALK4 insufficiency alleviated bladder fibrosis in a mouse model of pBOO partly by suppressing Smad2/3 activity.

Gene expression profiles during tissue remodeling following bladder outlet obstruction.

Bladder outlet obstruction (BOO) often results in lower urinary tract symptoms (LUTSs) and negatively affects quality of life. Here, we evaluated gene expression patterns in the urinary bladder during tissue remodeling due to BOO. We divided BOO model rats into two groups according to the degree of hypertrophy of smooth muscle in the bladder. The strong muscular hypertrophy group, which exhibited markedly increased bladder smooth muscle proportion and HIF1α mRNA levels compared with the control group, was considered a model for the termination of hypertrophy, whereas the mild muscular hypertrophy group was considered a model of the initiation of hypertrophy. Some genes related to urinary function showed different expression patterns between the two groups. Furthermore, we found that several genes, including D-box binding PAR bZIP transcription factor (DBP), were upregulated only in the mild muscular hypertrophy group. DBP expression levels were increased in bladder smooth muscle cells in response to hypoxic stress. DBP associated with enhancer and promoter regions of NOS3 gene locus and upregulated NOS3 gene expression under hypoxic conditions. These findings suggested that the regulatory systems of gene expression were altered during tissue remodeling following BOO. Furthermore, circadian clock components might be involved in control of urinary function via transcriptional gene regulation in response to hypoxic stimuli.

Urinary miRNA profiles discriminate between obstruction-induced bladder dysfunction and healthy controls.

Urgency, frequency and incomplete emptying are the troublesome symptoms often shared between benign prostatic obstruction-induced (BLUTD) and neurogenic (NLUTD) lower urinary tract dysfunction. Previously, using bladder biopsies, we suggested a panel of miRNA biomarkers for different functional phenotypes of the bladder. Urine is a good source of circulating miRNAs, but sex- and age-matched controls are important for urinary metabolite comparison. In two groups of healthy subjects (average age 32 and 57 years old, respectively) the total protein and RNA content was very similar between age groups, but the number of secreted extracellular vesicles (uEVs) and expression of several miRNAs were higher in the young healthy male volunteers. Timing of urine collection was not important for these parameters. We also evaluated the suitability of urinary miRNAs for non-invasive diagnosis of bladder outlet obstruction (BOO). A three urinary miRNA signature (miR-10a-5p, miR-301b-3p and miR-363-3p) could discriminate between controls and patients with LUTD (BLUTD and NLUTD). This panel of representative miRNAs can be further explored to develop a non-invasive diagnostic test for BOO. The age-related discrepancy in the urinary miRNA content observed in this study points to the importance of selecting appropriate, age-matched controls.

Bladder outlet obstruction disrupts circadian bladder function in mice.

The circadian clock programs daily rhythms and coordinates multiple behavioural processes, including micturition. Partial bladder outlet obstruction (pBOO) in mice produces hyperactive voiding. However, long-term effects of pBOO on bladder function have not been clarified. In this study, we investigated micturition under conditions of impaired circadian bladder function by inducing long-term pBOO by tying the proximal urethra. Micturition behavior was evaluated at 1, 3, 6 and 12 months after surgery. We used automated voided stain on paper method for a precise micturition recording for mice. And quantitative assessment of gene expression was performed at 24 months after pBOO surgery using qRT-PCR procedure. The micturition frequencies in the pBOO group were significantly decreased at 3, 6, and 12 months compared to those at 1 month after operation in the same group (p < 0.05). Body weight of pBOO mice was significantly increased compared to sham operated mice at 12 months. The expression level of mRNA was exhibited a 3.4-fold nominal increased for a 5-HT2B receptor in the pBOO group compared to the sham group. The current study found that long-term pBOO led to disruption of the circadian bladder function (the day/night cycle) in mice, similar to those observed in human as nocturia. This disruption is possible involvement of the gain of body weight and/or serotonergic alteration after pBOO.

Urethral meatus stricture BOO stimulates bladder smooth muscle cell proliferation and pyroptosis via IL­1ß and the SGK1­NFAT2 signaling pathway.

Bladder outlet obstruction (BOO), which is primarily caused by benign prostatic hyperplasia, is a common chronic disease. However, previous studies have most commonly investigated BOO using the acute obstruction model. In the present study, a chronic obstruction model was established to investigate the different pathological alterations in the bladder between acute and chronic obstruction. Compared with chronic obstruction, acute obstruction led to increased expression of proliferating cell nuclear antigen and interleukin­1ß, which are markers of proliferation and inflammation, respectively. Furthermore, increased fibrosis in the bladder at week 2 was observed. Low pressure promoted mice bladder smooth muscle cell (MBSMC) proliferation, and pressure overload inhibited cell proliferation and increased the proportion of dead MBSMCs. Further investigation using serum/glucocorticoid regulated kinase 1 (SGK1) small interfering RNAs indicated that low pressure may promote MBSMC proliferation by upregulating SGK1 and nuclear factor of activated T­cell expression levels. Therefore, the present study suggested that acute obstruction led to faster decompensation of bladder function and chronic bladder obstruction displayed an enhanced ability to progress to BOO.