Transforming growth factor-beta1–induced hypertrophy and matrix expression in human bladder smooth muscle cells

Immunomodulatory imide drugs inhibit human detrusor smooth muscle contraction and growth of human detrusor smooth muscle cells, and exhibit vaso-regulatory functions

BACKGROUND

The immunomodulatory imide drugs (IMiDs) thalidomide, lenalidomide and pomalidomide may exhibit therapeutic efficacy in the prostate. In lower urinary tract symptoms (LUTS), voiding and storage disorders may arise from benign prostate hyperplasia, or overactive bladder. While current therapeutic options target smooth muscle contraction or cell proliferation, side effects are mostly cardiovascular. Therefore, we investigated effects of IMiDs on human detrusor and porcine artery smooth muscle contraction, and growth-related functions in detrusor smooth muscle cells (HBdSMC).

METHODS

Cell viability was assessed by CCK8, and apoptosis and cell death by flow cytometry in cultured HBdSMC. Contractions of human detrusor tissues and porcine interlobar and coronary arteries were induced by contractile agonists, or electric field stimulation (EFS) in the presence or absence of an IMID using an organ bath. Proliferation was assessed by EdU assay and colony formation, cytoskeletal organization by phalloidin staining, RESULTS: Depending on tissue type, IMiDs inhibited cholinergic contractions with varying degree, up to 50 %, while non-cholinergic contractions were inhibited up to 80 % and 60 % for U46619 and endothelin-1, respectively, and EFS-induced contractions up to 75 %. IMiDs reduced viable HBdSM cells in a time-dependent manner. Correspondingly, proliferation was reduced, without showing pro-apoptotic effects. In parallel, IMiDs induced cytoskeletal disorganization.

CONCLUSIONS

IMiDs exhibit regulatory functions in various smooth muscle-rich tissues, and of cell proliferation in the lower urinary tract. This points to a novel drug class effect for IMiDs, in which the molecular mechanisms of action of IMiDs merit further consideration for the application in LUTS.

Activation of the TGF-β1/Smads/α-SMA pathway is related to histological and functional changes in children with neurogenic bladder

This research is to investigate the expression of the TGF-β1/Smads/α-SMA pathway and its effect on bladder histology and function in children with neurogenic bladder (NB). The bladder specimens from 10 children with NB and 8 children with vesicoureteral junction obstruction were collected into the NB and control groups. The expression of TGF-β1, Smad2, Smad3, Smad4, Smad6, α-SMA, fibronectin, collagen I and collagen III in bladder tissues was detected. In addition, the histological characteristics of the bladder were evaluated. A preoperative urodynamic study was performed on all children with NB. We analysed the correlations among the expression of the marker protein a-SMA in myofibroblasts, effector cells of the pathway, and bladder function parameters. Compared with those in the control group, the expression of TGF-β1, Smad2, Smad3, Smad4, α-SMA, fibronectin, collagen I and collagen III was significantly increased in the NB group, while the expression of Smad6 was decreased (p < 0.01). HE and Masson staining in the NB group showed increased collagen levels and hypertrophy of smooth muscle cells. Children with NB had a low bladder volume ratio (BVR), low compliance (△C) and high maximum bladder pressure, low maximum flow rate, large postvoid residual volume, low bladder contraction index and low bladder voiding efficiency. The expression of α-SMA was negatively correlated with the BVR (r =  − 0.7066, P = 0.0223) and △C (r =  − 0.6516, P = 0.0412). We conclude that the TGF-β1/Smads/α-SMA pathway is activated in the bladder tissue of children with NB and may be involved in the processes causing histological and functional changes.

Role of Urinary Transforming Growth Factor Beta-B1 and Monocyte Chemotactic Protein-1 as Prognostic Biomarkers in Posterior Urethral Valve

Background:

Posterior Urethral Valves (PUV) are the most common cause of congenital LUT obstruction in males. Biomarkers of glomerular or tubular injury may be of particular value in predicting the need for surgical intervention or in tracing progression of chronic kidney disease. Measurement of biomarker in urine is relatively easy.

Aim:

To evaluate the changes in values of urinary Transforming Growth Factor Beta 1(TGF-B1) and Monocyte Chemotactic Protein (MCP-1) before and after valve ablation and its prognostic value in Posterior urethral valve.

Material and Method:

This prospective study was conducted from September 2016 to August 2018. The study group included 20 consecutive male babies with the diagnosis of PUV treated and followed up versus equal numbers of age matched control without any renal or urinary tract disease. Pre-operative urine samples were collected in Operative room. Cystoscopy and valve ablation was done. Follow up was done clinically by urinary stream and radiologically with VCUG. Follow-up was planned at 1 month, 3 months and 6 months following cystoscopic valve ablation. All collected urine samples were centrifuged at 10,000 rpm for 20 minutes. Supernatant was collected and two divided aliquots were stored at -200c to be thawed on the day of assay. Optical density of each well was recorded at 450 nm and 540 nm A p-value of <0.05 was considered to be statistically significant.

Result and Discussion:

Out of 20 cases of PUV, 14 (70%) cases were 1st born males of their family. The median age at the time of valve ablation in PUV cases was 2.5 (1.20-3.87) years.. Most common symptoms are fever and UTI. The preoperative median serum creatinine level was 1.65 mg/dl(1.22-2.42) pre-ablation, and fall significantly after ablation. Median eGFR level (calculated) was 25.635 (16.38-35.40) and after 6 months was 71.490 (45.44-96.93). Preoperative median MCP1 in PUV cases was 147.2 (82.8-512.5) and significant difference was also found in 1st, 3rd and 6th months after surgery (p<0.001, p=0.004 and p=0.002).Preoperative median TGF-B1 level was 197.8 pg/ml (79.9-386.4). There was no statistically significant change in TGF-B1 level at preoperative to 1 month and preop to 3 months after surgery but at 6 months after surgery the median TGF-B1 level significantly decreased as compared with preoperative TGF-B1 level.

Conclusion:

TGF β1 and MCP1 can be considered as prognostic urinary biomarkers in patients of PUV and can be used to specify and counsel patient's attendant regarding possibility of ESRD and need for further intervention.

Effect of amniotic fluid stem cell transplantation on the recovery of bladder dysfunction in spinal cord-injured rats

The effects of human amniotic fluid stem cell (hAFSC) transplantation on bladder function and molecular changes in spinal cord-injured (SCI) rats were investigated. Four groups were studied: sham and SCI plus phosphate-buffered saline (SCI + PBS), human embryonic kidney 293 (HEK293) cells, and hAFSCs transplantation. In SCI + PBS rat bladders, cystometry showed increased peak voiding pressure, voiding volume, bladder capacity, residual volume, and number of non-voiding contractions, and the total elastin/collagen amount was increased but collagen concentration was decreased at days 7 and 28. Immunoreactivity and mRNA levels of IGF-1, TGF-β1, and β3-adrenoceptor were increased at days 7 and/or 28. M2 immunoreactivity and M3 mRNA levels of muscarinic receptor were increased at day 7. M2 immunoreactivity was increased, but M2/M3 mRNA and M3 immunoreactivity levels were decreased at day 28. Brain derived-neurotrophic factor mRNA was increased, but immunoreactivity was decreased at day 7. HEK293 cell transplantation caused no difference compared to SCI + PBS group. hAFSCs co-localized with neural cell markers and expressed BDNF, TGF-β1, GFAP, and IL-6. The present results showed that SCI bladders released IGF-1 and TGF-β1 to stimulate elastin and collagen for bladder wall remodelling, and hAFSC transplantation improved these changes, which involved the mechanisms of BDNF, muscarinic receptors, and β3-adrenoceptor expression.

Glycine tomentella hayata extract and its ingredient daidzin ameliorate cyclophosphamide-induced hemorrhagic cystitis and oxidative stress through the action of antioxidation, anti-fibrosis, and anti-inflammation

We explored the therapeutic potential of intragastric administration of traditional Chinese medicine Glycine tomentella Hayata (I-Tiao-Gung [ITG]) extract and its major component Daidzin on cyclophosphamide (CYP)-induced cystitis, oxidative stress, fibrosis, inflammation, and bladder hyperactivity in rats. Female Wistar rats were divided into control, CYP (200 mg/kg), CYP+ITG (1.17 g/kg/day), and CYP+Daidzin (12.5 mg/kg/day) groups. We measured the voiding function by the transcystometrogram and evaluated the pathology with the hematoxylin and eosin and Masson stain. We determined the bladder reactive oxygen species (ROS) amount by an ultrasensitive chemiluminescence analyzer, the expression of 3-nitrotyrosine (3-NT) and NADPH oxidase 4 (NOX4) by Western blot and the expression of multiple cytokine profiles, including matrix metalloproteinase (MMP)-8 and tissue inhibitor of metalloproteinase (TIMP)-1 through a cytokine array. ITG extract contains 1.07% of Daidzin through high-performance liquid chromatography. The effect of ITG extract and Daidzin in scavenging hydrogen peroxide activity was more efficient than distilled water. CYP-induced higher urination frequency, shorter intercontraction interval, and lower maximal voiding pressure in the bladders and these symptoms were significantly ameliorated in CYP+ITG and CYP+Daidzin groups. The amount of in vivo bladder ROS and the expression of 3-NT and NOX4 expressions were significantly increased in CYP group but were efficiently decreased in the CYP+ITG and CYP+Daidzin groups. CYP-induced fibrosis, hemorrhage, leukocyte infiltration, and edema in the bladders were significantly attenuated in the CYP+ITG and CYP+Daidzin groups. These results suggested that ITG extract and its active component Daidzin effectively improved CYP-induced oxidative stress, inflammation, and fibrosis through inhibiting the MMP-8, TIMP-1, and oxidative stress.

Long-term diabetes causes molecular alterations related to fibrosis and apoptosis in rat urinary bladder

Diabetes induces time-dependent alterations in urinary bladders. Long-term diabetes causes an underactive bladder. However, the fundamental mechanisms are still elusive. This study aimed to examine the histological changes and the potential molecular pathways affected by long-term diabetes in the rat bladder. Diabetes was induced in 8-week-old male Lewis rats by streptozotocin, while age-matched control rats received citrate buffer only. Forty-four weeks after diabetes induction, bladders were harvested for histological and molecular analyses. The expressions of proteins related to fibrosis, apoptosis and oxidative stress as well as the cellular signaling pathway in the bladder were examined by immunoblotting. Histological examinations illustrated diabetes caused detrusor hypertrophy and fibrotic changes in the bladder. Immunoblotting analysis demonstrated higher collagen I but lower elastin expression in the bladder in diabetic rats. These were accompanied by an increase in the expression of transforming growth factor-beta1, along with the downregulation of matrix metalloptoteinase-1, and upregulation of tissue inhibitor of metalloproteinase-1. Diabetic rats showed an increase in nitrotyrosine, but decrease in nuclear factor erythroid-related factor 2 (Nrf2) levels in the bladder. Enhanced apoptotic signaling was observed, characterized by increased expression of Bcl-2-associated X protein (Bax), decreased expression of Bcl-2, in the diabetic bladder. The nerve growth factor level was decreased in the diabetic bladder. A significant suppression in the protein expressions of phosphorylated extracellular signal-regulated kinases 1/2 was found in diabetic bladders. This study demonstrated that long-term diabetes caused molecular changes that could promote fibrosis and apoptosis in the bladder. Oxidative stress may be involved in this context.

Mesenchymal stem cell therapy inhibited inflammatory and profibrotic pathways induced by partial bladder outlet obstruction and prevented high-pressure urine storage

BACKGROUND

Partial bladder outlet obstruction (pBOO) is characterized by an initial inflammatory response that progresses to smooth muscle hypertrophy and fibrosis. Current treatment modalities carry high risk of morbidity. Mesenchymal stem cells (MSCs) are undifferentiated adult cells with reparative, immunomodulatory, and anti-inflammatory capacities. The ability of MSCs to inhibit inflammatory and profibrotic pathways in bladder cells has been recently reported.

OBJECTIVES

This study aimed to investigate the therapeutic effects of MSCs on pBOO-induced inflammatory, profibrotic signaling pathways and end-organ physiology.

MATERIALS AND METHODS

Twenty Sprague Dawley rats were randomly assigned to 5 groups: unobstructed controls, pBOO for 2 and 4 weeks, pBOO+MSCs for 2 and 4 weeks. Partial bladder outlet obstruction was surgically induced followed by intravenous injection of MSCs. Endpoint urodynamics was performed, and bladder tissue harvested for analysis. Reverse transcription real time polymerase chain reaction (RT-PCR) and immunohistochemistry were performed to study gene and protein expression of major inflammatory and profibrotic markers.

RESULTS

Partial bladder outlet obstruction resulted in an upregulation of transforming growth factor beta (TGFβ1), mothers against decapentaplegic homolog 2/3 (SMAD2/3), hypoxia inducible factor 1 alpha (HIF1α), hypoxia inducible factor 3 alpha (HIF3α), vascular endothelial growth factor (VEGF), tumor necrosis factor (TNFα), mechanistic target of rapamycin (mTOR), p70 ribosomal S6 protein kinase (p70 S6K), collagen 1 (COL1), and collagen 3 (COL3) expression in a time-dependent manner. This was coupled with a downregulation of interleukin (IL)-10 expression. Increase of bladder fibrosis was directly related to the duration of pBOO and associated with high urine storage pressure. Injected MSCs were identified in the bladder 4 weeks after therapy. The immunomodulatory effect of MSCs(defined by reduced TNFα and increased IL-10 and VEGF) was most predominant 2 weeks after therapy. Significant downregulation of profibrotic genes occurred 4 weeks after therapy. End filling pressure, hypertrophy, and fibrosis were significantly reduced after MSC therapy (P < 0.05).

DISCUSSION

Mesenchymal stem cell therapy led to a profound systematic improvement of the obstructed bladder. This included an initial anti-inflammatory response and a subsequent antifibrotic reaction. Essentially, both phases were associated with a reduction of urine storage pressure. The intravenously injected MSCs were tracked in the bladder. However, their presence in non-target organs such as the lungs, spleen, and liver was not tracked.

CONCLUSIONS

Partial bladder outlet obstruction induced significant upregulation of hypoxic, inflammatory, and profibrotic markers. Mesenchymal stem cell therapy potently inhibited these pathways and improved bladder function.

A comparison of prenatal muscle transcriptome and proteome profiles between pigs with divergent growth phenotypes

The growth of pigs is an important economic trait that involves multiple genes and coordinated regulatory mechanisms. The growth rate and potential of skeletal muscles are largely decided by embryonic myofiber development. Tibetan pig (TP) that is a mini-type breed has a divergent phenotype in growth rate and adult body weight with Wujin pig (WJ) and large White pig (LW). In the current study, the transcriptome (using RNA-seq) and proteome (using the isobaric tag for relative and absolute quantification [iTRAQ]) data from the prenatal muscle tissues were analyzed to identify the genes related to postnatal growth rate and growth potential in pigs. In the RNA-seq experiment, 19 626 genes were detected in the embryonic muscle tissues, and 3626 unique differentially expressed genes (DEGs) were identified in TP in comparison to that in LW and WJ. In the iTRAQ experiment, 2474 proteins were detected, and 735 unique differentially expressed proteins (DEPs) were identified in TP in comparison to that in LW and WJ. Combining the DEGs and DEPs, 209 genes were found to be differentially expressed, consistently at both the messenger RNA and protein levels, between TP and the other two breeds; these are mainly involved in 2-oxocarboxylic acid metabolism, citrate cycle, and biosynthesis of amino acids. Of these, 20 genes that were related to myoblast differentiation and muscle fiber formation might have important roles in determining the postnatal growth rate and potential body weight in pigs. Our results provide new candidate genes and insights into the molecular mechanisms involved muscle growth traits in pigs.

Can bladder fibrosis in congenital urinary tract obstruction be reversed?

A variety of conditions exists in adults and children in which functional or anatomical urinary tract obstructions cause bladder fibrosis, which reduces the bladder's ability to store and empty urine. Current surgical procedures include removal of the obstructions to facilitate bladder emptying or prompt prenatal or postnatal spinal closure to prevent further neurogenic damage. Bladder fibrosis may occur, and it can get worse if a flow hindrance persists or deteriorates. Anti-fibrotic therapeutic strategies that target a variety of factors have been developed in animal models, but currently there are no anti-fibrotic therapies available for clinical use. This review examines the pathogenesis of bladder fibrosis that is caused by congenital obstructions of the lower urinary tract, and it focuses on the principal signalling factors and potential treatment modalities.

Role of the TGF-β pathway in dedifferentiation of human mature adipocytes

Dedifferentiation of adipocytes contributes to the generation of a proliferative cell population that could be useful in cellular therapy or tissue engineering. Adipocytes can dedifferentiate into precursor cells to acquire a fibroblast‐like phenotype using ceiling culture, in which the buoyancy of fat cells is exploited to allow them to adhere to the inner surface of a container. Ceiling culture is usually performed in flasks, which limits the ability to test various culture conditions. Using a new six‐well plate ceiling culture approach, we examined the relevance of TGF‐β signaling during dedifferentiation. Adipose tissue samples from patients undergoing bariatric surgery were digested with collagenase, and cell suspensions were used for ceiling cultures. Using the six‐well plate approach, cells were treated with SB431542 (an inhibitor of TGF‐β receptor ALK5) or human TGF‐β1 during dedifferentiation. Gene expression was measured in these cultures and in whole adipose tissue, the stromal–vascular fraction (SVF), mature adipocytes, and dedifferentiated fat (DFAT) cells. TGF‐β1 and collagen type I alpha 1 (COL1A1) gene expression was significantly higher in DFAT cells compared to whole adipose tissue samples and SVF cells. TGF‐β1, COL1A1, and COL6A3 gene expression was significantly higher at day 12 of dedifferentiation compared to day 0. In the six‐well plate model, treatment with TGF‐β1 or SB431542, respectively, stimulated and inhibited the TGF‐β pathway as shown by increased TGF‐β1, TGF‐β2, COL1A1, and COL6A3 gene expression and decreased expression of TGF‐β1, COL1A1, COL1A2, and COL6A3, respectively. Treatment of DFAT cells with TGF‐β1 increased the phosphorylation level of SMAD 2 and SMAD 3. Thus, a new six‐well plate model for ceiling culture allowed us to demonstrate a role for TGF‐β in modulating collagen gene expression during dedifferentiation of mature adipocytes.

Temporal Changes in Gene Expression Profile during Mature Adipocyte Dedifferentiation

Objective. To characterize changes in gene expression profile during human mature adipocyte dedifferentiation in ceiling culture. Methods. Subcutaneous (SC) and omental (OM) adipose tissue samples were obtained from 4 participants paired for age and BMI. Isolated adipocytes were dedifferentiated in ceiling culture. Gene expression analysis at days 0, 4, 7, and 12 of the cultures was performed using Affymetrix Human Gene 2.0 STvi arrays. Hierarchical clustering according to similarity of expression changes was used to identify overrepresented functions. Results. Four clusters gathered genes with similar expression between day 4 to day 7 but decreasing expression from day 7 to day 12. Most of these genes coded for proteins involved in adipocyte functions (LIPE, PLIN1, DGAT2, PNPLA2, ADIPOQ, CEBPA, LPL, FABP4, SCD, INSR, and LEP). Expression of several genes coding for proteins implicated in cellular proliferation and growth or cell cycle increased significantly from day 7 to day 12 (WNT5A, KITLG, and FGF5). Genes coding for extracellular matrix proteins were differentially expressed between days 0, 4, 7, and 12 (COL1A1, COL1A2, and COL6A3, MMP1, and TGFB1). Conclusion. Dedifferentiation is associated with downregulation of transcripts encoding proteins involved in mature adipocyte functions and upregulation of genes involved in matrix remodeling, cellular development, and cell cycle.

Hypoxia-increased expression of genes involved in inflammation, dedifferentiation, pro-fibrosis, and extracellular matrix remodeling of human bladder smooth muscle cells

Partial bladder outlet obstruction (pBOO) is characterized by exaggerated stretch, hydrodynamic pressure, and inflammation which cause significant damage and fibrosis to the bladder wall. Several studies have implicated hypoxia in its pathophysiology. However, the isolated progressive effects of hypoxia on bladder cells are not yet defined. Sub-confluent normal human bladder smooth muscle cells (hbSMC) were cultured in 3% O2 tension for 2, 24, 48, and 72 h. RNA, cellular proteins, and secreted proteins were used for gene expression analysis, immunoblotting, and ELISA, respectively. Transcription of hypoxia-inducible factor (HIF)1α and HIF2α were transiently induced after 2 h of hypoxia (p < 0.05), whereas HIF3 was upregulated after 72 h (p < 0.005). HIF1 and HIF3α proteins were significantly induced after 2 and 72 h, respectively. VEGF mRNA increased significantly after 24 and 72 h (p < 0.005). The inflammatory cytokines, TGFB (protein and mRNA), IL 1β, 1L6, and TNFα (mRNA) demonstrated a time-dependent increased expression. Furthermore, the anti-inflammatory cytokine IL-10 was downregulated after 72 h (p < 0.05). Evidence of smooth muscle cell dedifferentiation included increased αSMA, vimentin, and desmin. Evidence of pro-fibrotic changes included increased CTGF, SMAD 2, and SMAD 3 as well as collagens 1, 2, 3, and 4, fibronectin, aggrecan, and TIMP 1 transcripts (p < 0.05). Total collagen proteins also increased time-dependently (p < 0.05). Together, these results show that exposure of hbSMC to low oxygen tension results in intense hypoxic cascade, including inflammation, de-differentiation, pro-fibrotic changes, and increased extracellular matrix expression. This elucidates mechanisms of hypoxia-driven bladder deterioration in bladder cells, which is important in tailoring in vivo experiments and may ultimately translate into improved clinical outcomes.

Benefits of mesenchymal stem cells after partial bladder outlet obstruction

INTRODUCTION

Partial bladder outlet obstruction (pBOO) results in significant morbidity and mortality in the pediatric and adult populations. Mesenchymal stem cells (MSC) have been widely studied in many organ systems for the treatment and prevention of fibrotic and inflammatory conditions. Therefore, we hypothesize that systemic administration of MSC will demonstrate short-term biochemical, histological, and urodynamic benefits in an animal model for pBOO.

METHODS

After University ethics approval, 5 × 106 green fluorescent protein GFP-labeled MSC were intravenously injected concurrently with pBOO in adult Sprague-Dawley rats. Five groups (n=3/group) were analyzed: a) unobstructed controls; b) pBOO for seven days with intravenous MSC (7d+MSC); c) pBOO for seven days without intravenous MSC (7d-MSC); d) pBOO for 14 days with intravenous MSC (14d+MSC), e) pBOO for 14 days without MSC (14d-MSC). Urodynamics were performed at the end of the experimental period and bladders were weighed. Immunohistochemistry was performed for GFP detection and reverse transcription polymerase chain reaction (RT-PCR) to detect mRNA of: TGF-B, HIF-1a, RhoA, GRP-78, lumican, and decorin.

RESULTS

All animals remained healthy. GFP was detected in all treatment groups. MSC treatment resulted in a significant decrease in bladder capacity (0.91 cc vs. 2.15 cc, p=0.04). Treatment also resulted in significant decreases in mRNA levels of: TGF-B, HIF-1a, Rho-A, and GRP-78.

CONCLUSIONS

Systemic treatment with MSC was well tolerated and resulted in MSC accumulation after pBOO. Despite our low numbers, we were able to successfully demonstrate short-term urodynamic improvements and widespread, significant decreases in inflammatory mediators. We believe that this decreased inflammatory cascade will help prevent long-term detrusor deterioration.

MiR-133 modulates TGF-β1-induced bladder smooth muscle cell hypertrophic and fibrotic response: implication for a role of microRNA in bladder wall remodeling caused by bladder outlet obstruction

Bladder outlet obstruction (BOO) evokes urinary bladder wall remodeling significantly, including the phenotype shift of bladder smooth muscle cells (BSMCs) where transforming growth factor-beta1 (TGF-β1) plays a pivotal role given the emerging function of modulating cellular phenotype. miR-133 plays a role in cardiac and muscle remodeling, however, little is known about its roles in TGF-β1-induced BSMC hypertrophic and fibrotic response. Here, we verified BOO induced bladder wall remodeling and TGF-β1 expression mainly located in bladder endothelium. Furthermore, we uncovered miR-133a/b expression profile in BOO rats, and then explored its regulated effects on BSMCs' phenotypic shift. Our study found that miR-133 became down-regulated during rat bladder remodeling. Next, we sought to examine whether the expression of miR-133 was down-regulated in primary BSMCs in response to TGF-β1 stimulation and whether forced overexpression of miR-133 could regulate profibrotic TGF-β signaling. We found that stimulation of BSMCs with exogenous TGF-β1 of increasing concentrations resulted in a dose-dependent decrease of miR-133a/b levels and transfection with miR-133 mimics attenuated TGF-β1-induced α-smooth muscle actin, extracellular matrix subtypes and fibrotic growth factor expression, whereas it upregulated high molecular weight caldesmon expression compared with the negative control. Also, downregulation of p-Smad3, not p-Smad2 by miR-133 was detected. Additionally, miR-133 overexpression suppressed TGF-β1-induced BSMC hypertrophy and proliferation through influencing cell cycle distribution. Bioinformatics analyses predicted that connective tissue growth factor (CTGF) was the potential target of miR-133, and then binding to the 3'-untranslated region of CTGF was validated by luciferase reporter assay. These results reveal a novel regulator for miR-133 to modulate TGF-β1-induced BSMC phenotypic changes by targeting CTGF through the TGF-β-Smad3 signaling pathway. A novel antifibrotic functional role for miR-133 is presented which may represent a potential target for diagnostic and therapeutic strategies in bladder fibrosis.

The urinary bladder of spontaneously hypertensive rat demonstrates bladder hypertrophy, inflammation, and fibrosis but not hyperplasia

AIMS

The present study aims to systemically characterize the factors that are associated with urinary bladder organ enlargement in spontaneously hypertensive rats (SHR).

MAIN METHODS

We compared the SHR to age-matched normotensive Wistar-Kyoto (WKY) control rats in the levels of bladder pro-inflammatory factors, collagen expression (type I), and detrusor smooth muscle growth.

KEY FINDINGS

Our results showed that enhanced inflammatory responses and fibrosis were key factors that were closely associated with bladder wall thickening in SHR. Specifically the mRNA levels of inflammatory factors interleukin (IL)-1α, IL-6 and TNFα were significantly higher in SHR than those in WKY rats. The SHR also had a higher number of mast cells in the suburothelium space. Type I collagen production was also significantly higher in SHR when compared to that in control rats. However, the smooth muscle content stayed the same in SHR and WKY rats. This was shown by the results that the ratio of α-smooth muscle actin (SMA) to the nuclear protein histone H3 had no difference between these two rat strains. The mRNA and protein levels of proliferating cell nuclear antigen (PCNA) also showed no change in the urinary bladder of SHR and WKY rats. Further study showed that the phosphorylation level of Akt in the urinary bladder was not changed in SHR when compared to WKY rats. In contrast, the phosphorylation level of ERK1/2 was significantly higher in SHR bladder when compared to that of WKY rats.

SIGNIFICANCE

These results suggest that inflammation and fibrosis are primary factors that may lead to urinary bladder hypertrophy in SHR.

Impaired detrusor contractility in a rat model of chronic bladder ischemia

OBJECTIVE

To examine the effect of chronic ischemia associated with vascular disorders on bladder function, we investigated bladder contractility and changes in morphology and nerve distribution in a rat model of chronic bladder ischemia.

METHODS

Adult male Sprague-Dawley rats were divided into arterial endothelial injury, sham, and control groups. The injury group underwent balloon endothelial injury of the iliac arteries and received a 2% cholesterol diet. The sham group was only incised bilaterally in the inguinal region and received the 2% cholesterol diet. The control group did not undergo any procedure and received a regular diet (0.09% cholesterol). All animals were euthanized after 8 weeks. Bladders were removed and weighed, and sections were used for muscle strip contraction and histologic analyses. Cross-sections of dissected common iliac arteries were examined histologically.

RESULTS

Bladder contractile response and tension were significantly decreased in the injury group compared with the sham and control groups. Tissue from the injury group exhibited marked arterial occlusion with wall thickening. In the injury group, the collagen and muscle ratio (0.80 ± 0.12) was significantly greater than in the control (P = .01) and sham (P = .04) groups. Significantly fewer protein gene product 9.5 (PGP9.5)-positive nerve fibers were found in the injury group (513 ± 53) than in the control (P = .01) and sham (P = .03) groups.

CONCLUSION

Vascular occlusive disorders cause fibrosis and reduce the number of nerves innervating the bladder, which leads to decreased bladder contractility in a rat model of chronic bladder ischemia.

Regulation of IGF-1 but not TGF-β1 by NGF in the smooth muscle of the inflamed urinary bladder

Intraperitoneal injection of cyclophosphamide (CYP) causes hemorrhagic cystitis with excess growth of muscular layer leading to bladder hypertrophy; this could be attributable to changes in the expression profiles of growth factors in the inflamed urinary bladder. The growth factors characterized in the current study include nerve growth factor (NGF), insulin-like growth factor (IGF)-1, and transforming growth factor (TGF)-β1. We found that following CYP injection for 8 h and 48 h, the mRNA levels of all three factors were increased in the inflamed bladder when compared to control. The level of NGF mRNA was mainly increased in the urothelium layer while the levels of IGF-1 mRNA and TGF-β1 mRNA were increased in the smooth muscle layer. The level of NGF high affinity receptor TrkA mRNA was also increased in both the urothelium and the smooth muscle layers during bladder inflammation. When we blocked NGF action with NGF neutralizing antibody in vivo, we found that the up-regulation of IGF-1 in the inflamed bladder was reversed while the up-regulation of TGF-β1 was not affected by NGF neutralization. The effect of NGF on regulating IGF-1 expression was further confirmed in bladder smooth muscle culture showing that exogenous NGF increased the mRNA level of IGF-1 after 30 min to 1 h stimulation. These results suggested that bladder inflammation induced region-specific changes in the expression profiles of NGF, IGF-1 and TGF-β1. The up-regulation of NGF in the urothelium may have a role in affecting bladder smooth muscle cell physiology by regulating IGF-1 expression.

Strain history and TGF-β1 induce urinary bladder wall smooth muscle remodeling and elastogenesis

Mechanical cues that trigger pathological remodeling in smooth muscle tissues remain largely unknown and are thought to be pivotal triggers for strain-induced remodeling. Thus, an understanding of the effects mechanical stimulation is important to elucidate underlying mechanisms of disease states and in the development of methods for smooth muscle tissue regeneration. For example, the urinary bladder wall (UBW) adaptation to spinal cord injury (SCI) includes extensive hypertrophy as well as increased collagen and elastin, all of which profoundly alter its mechanical response. In addition, the pro-fibrotic growth factor TGF-β1 is upregulated in pathologies of other smooth muscle tissues and may contribute to pathological remodeling outcomes. In the present study, we utilized an ex vivo organ culture system to investigate the response of UBW tissue under various strain-based mechanical stimuli and exogenous TGF-β1 to assess extracellular matrix (ECM) synthesis, mechanical responses, and bladder smooth muscle cell (BSMC) phenotype. Results indicated that a 0.5-Hz strain frequency triangular waveform stimulation at 15% strain resulted in fibrillar elastin production, collagen turnover, and a more compliant ECM. Further, this stretch regime induced changes in cell phenotype while the addition of TGF-β1 altered this phenotype. This phenotypic shift was further confirmed by passive strip biomechanical testing, whereby the bladder groups treated with TGF-β1 were more compliant than all other groups. TGF-β1 increased soluble collagen production in the cultured bladders. Overall, the 0.5-Hz strain-induced remodeling caused increased compliance due to elastogenesis, similar to that seen in early SCI bladders. Thus, organ culture of bladder strips can be used as an experimental model to examine ECM remodeling and cellular phenotypic shift and potentially elucidate BMSCs ability to produce fibrillar elastin using mechanical stretch either alone or in combination with growth factors.

Phenotypic modulation of human urinary tract stroma-derived fibroblasts by transforming growth factor beta3

OBJECTIVES

Animal models have described critical roles for transforming growth factor beta (TGFbeta) isoforms in modulating urinary tract stroma phenotype. TGFbeta3 is of particular interest because it may regulate TGFbeta1 and TGFbeta2 expression, but its modulatory affect has not been so well characterized in human cells. In this study, we aim to determine whether TGFbeta3 treatment induced differentiation of human urinary tract stroma-derived fibroblasts to a smooth muscle-like phenotype.

METHODS

We established cultures of human urinary tract stroma-derived fibroblasts and studied the effects of TGFbeta3 treatment using proliferation assays, cell cycle analysis, immunocytochemistry, and Western blotting for expression of differentiation marker and downstream regulators, and fura-2 fluorescence to study the effects on intracellular calcium.

RESULTS

TGFbeta3 treatment induced proliferation that peaked at 72 hours, followed by enhanced expression of alpha-smooth muscle actin (alpha-SMA) with a maximal 3.4-fold increase at 168 hours. TGFbeta3 treatment decreased resting [Ca(2+)](i) by 70% and caused a 95% decrease in stimulated internal Ca(2+) release regulated by the sarcoplasmic/endoplasmic calcium-ATPase pump. These effects were associated with upregulation of nuclear activator of T cells -1 (NFAT), a known regulator of cell differentiation.

CONCLUSIONS

TGFbeta3 treatment causes a time-specific response in the presence of serum, whereby fibroblasts initially proliferate and subsequently differentiate to a smooth muscle-like phenotype. This sequence was associated with stabilization of [Ca(2+)](i) stores, suggesting a role in the induction of hyperplasia and reduction of contractility; phenomena associated with a number of urinary tract pathologies.

Endogenous nerve growth factor regulates collagen expression and bladder hypertrophy through Akt and MAPK pathways during cystitis

Type I collagen forms the main constituent of the extracellular matrix in visceral organs. We reported here that cyclophosphamide (CYP)-induced cystitis significantly increased the production of type I collagen in the inflamed bladder leading to increases in the bladder weight and the thickness of the bladder wall. The endogenous nerve growth factor (NGF) in the urinary bladder regulated type I collagen expression because the neutralizing NGF antibody attenuated cystitis-induced type I collagen up-regulation in the inflamed bladder. Neutralizing NGF antibody also subsequently reversed cystitis-induced increases in bladder weight. Further studies on the intermediate signaling pathways mediating NGF-induced type I collagen expression in the inflamed bladder during cystitis revealed that Akt, JNK, and ERK1/2 activities were increased in the inflamed bladder, whereas p38 MAPK remained unchanged. Suppression of endogenous NGF level with neutralizing NGF antibody significantly blocked the increased activity of Akt, JNK, and ERK1/2 in the inflamed bladder during cystitis. These results indicate that endogenous NGF plays an important role in the activation of Akt and MAPK in the urinary bladder and in bladder hypertrophy during cystitis.

Gender-based reciprocal expression of transforming growth factor-beta1 and the inducible nitric oxide synthase in a rat model of cyclophosphamide-induced cystitis

BACKGROUND

The pluripotent cytokine transforming growth factor-beta1 (TGF-beta1) is the central regulator of inducible Nitric Oxide Synthase (iNOS) that is responsible for nitric oxide (NO) production in inflammatory settings. Previous studies have implicated a role for NO, presumably derived from iNOS, in cyclophosphamide (CYP)-induced cystitis in the bladder. TGF-beta1 is produced in latent form and requires dissociation from the latency-associated peptide (LAP) to act as primary anti-inflammatory and pro-healing modulator following tissue injury in the upper urinary tract. Since the role of TGF-beta1 in lower urinary tract inflammation is currently unknown, and since gender-based differences exist in the setting of interstitial cystitis (IC), the present study examined the relationship between TGF-beta1 and iNOS/NO in the pathogenesis of CYP-induced cystitis in both male and female rats.

METHODS

Sprague-Dawley rats, 4 months of age, of either gender were given 150 mg/kg CYP intraperitoneally. Urinary and bladder tissue TGF-beta1 and NO reaction products (NO2-/NO3-) were quantified as a function of time following CYP. Expression of active and latent TGF-beta1 as well as iNOS in harvested bladder tissue was assessed by immunohistochemistry.

RESULTS

Female rats had significantly higher levels of NO2-/NO3- in urine even at baseline as compared to male rats (p < 0.001), whereas there was no gender based significant difference in urine levels of active or latent TGF-beta1 prior to CYP injection. Inflammatory and cytotoxic changes were induced by CYP in the bladder of both sexes that were accompanied by differences in the urine levels of NO2-/NO3- and TGF-beta1. Male rats responded to CYP with significantly lower levels of NO2-/NO3- and significantly higher levels of TGF-beta1 in urine (p < 0.05) as compared to females at all time points after CYP. The urine levels of NO2-/NO3- after CYP were inversely correlated to latent and active TGF-beta1 (Pearson coefficient of -0.72 and -0.69 in females and -0.89 and -0.76 in males, respectively; p < 0.01). Bladder tissue of male rats exhibited significantly higher levels of both latent and active TGF-beta1 (p < 0.01) compared to female rats after CYP. TGF-beta1 and iNOS protein was mostly localized in the urothelium.

CONCLUSION

The results of this study suggest that there exists an inverse relationship between the expression of TGF-beta1 and iNOS/NO2-/NO3- in CYP-inflamed bladder. The gender of the animal appears to magnify the differences in urine levels of TGF-beta1 and NO2-/NO3- in this inflammatory setting. These results support the hypothesis that TGF-beta1 can suppress iNOS expression associated with bladder inflammation and reduce systemic levels of NO2-/NO3-, and further suggest that this feature of TGF-beta1 can be harnessed for therapy and diagnosis of interstitial cystitis.

Assessing the effects of transforming growth factor-beta1 on bladder smooth muscle cell phenotype. I. Modulation of in vitro contractility

PURPOSE

Modulation of the bladder smooth muscle cell phenotype contributes to the resulting bladder dysfunction in many pathological bladder conditions. Transforming growth factor-beta1 is an important regulator of cellular phenotype in fibrotic diseases that has specific effects on bladder smooth muscle cells associated with phenotypic changes. We verified transforming growth factor-beta1 expression in neurogenic bladder tissue and investigated its effects on bladder smooth muscle cell collagen gel contraction.

MATERIALS AND METHODS

Transforming growth factor-beta1 immunostaining was performed on tissue sections from spinalized rats and quantified based on the ratio of fluorescence to total detrusor area. Rat bladder smooth muscle cells were seeded at different densities on anchored collagen gels and the effect of transforming growth factor-beta1 on contractility was assessed by measuring changes in the collagen gel area with time. Phenotypic changes induced by transforming growth factor-beta1 were detected by immunostaining for caldesmon and the specific isoform high molecular weight caldesmon.

RESULTS

Transforming growth factor-beta1 immunostaining revealed increased levels specifically in the detrusor of spinal cord injured rats. Rat bladder smooth muscle cell contraction increased with larger cell populations and was inhibited by transforming growth factor-beta1. Transforming growth factor-beta1 induced a decrease in high molecular weight caldesmon expression in bladder smooth muscle cells.

CONCLUSIONS

Increased transforming growth factor-beta1 expression in the detrusor of spinal cord injured rats implies up-regulation and localized signaling in response to injury. Bladder smooth muscle cells showed a loss of contractility in response to transforming growth factor-beta1 in all cell populations. A shift in phenotype was confirmed by high molecular weight caldesmon immunostaining. These results suggest that transforming growth factor-beta1 can modulate bladder smooth muscle cell function and may be a crucial regulator of bladder smooth muscle cell phenotype in pathological bladder conditions.

Time-dependent alterations of select genes in streptozotocin-induced diabetic rat bladder

OBJECTIVES

To investigate time-course changes in the expression of select genes and extracellular matrix proteins in the bladder of rats with streptozotocin-induced diabetes, so as to examine the mechanisms underlying changes in mechanical properties of the bladder due to diabetic cystopathy.

METHODS

Female Sprague-Dawley rats were injected with streptozotocin (65 mg/kg). Rats that were fed with 5% sucrose in drinking water served as diuretic controls, in addition to normal control rats. At the end of 2, 4, and 8 weeks, total ribonucleic acid (RNA) isolated from the detrusor layer of the bladders was reverse transcribed, and then complementary deoxyribonucleic acid was amplified with polymerase chain reaction primer sets for type I collagen, type III collagen, tropoelastin, and transforming growth factor beta 1 (TGF-beta-1). Collagen and elastin contents of the bladders were quantified with commercially available assays.

RESULTS

Both diabetic and diuretic rat bladders exhibited significantly (P <0.05) lower expression of type I collagen and TGF-beta-1 messenger RNA (mRNA) compared with normal controls at all time points tested. In contrast, downregulation of type III collagen mRNA expression in both diabetic and diuretic groups was seen at 4 and 8 weeks. Furthermore, tropoelastin mRNA expression in the diabetic rat bladders was, compared with normal and diuretic rats, significantly (P <0.05) greater at 2 weeks. Both diabetic and diuretic rat bladders exhibited significantly (P <0.05) decreased collagen and increased elastin protein content at 2 and 8 weeks.

CONCLUSIONS

The results of the present study suggest that increases in compliance of the bladders in diabetic cystopathy result not only from diuresis-driven reduction of collagen synthesis but also from increased elastin synthesis.

Expression of transforming growth factor β1 gene, basic fibroblast growth factor gene and hydroxyproline in diabetes-induced bladder dysfunction in a rat model

AIMS

To investigate the content of hydroxyproline (Hyp) and the expression of transforming growth factor beta1 (TGF beta1) and basic fibroblast growth factor (bFGF) in the bladder 8 weeks after diabetes induction.

METHODS

Thirty wistar rats were divided into three groups: control (n = 10), streptozotocin-induced diabetic group (n = 10), TAD group (n = 10; diabetic rats were fed with Tadenan 100 mg kg(-1) day(-1)). Eight weeks later, the bladders were dissected. RT-PCR, immunohistochemistry, and ELISA were used to detect the expression of TGF beta1 and bFGF in the bladder. Also hydroxyproline (Hyp) was measured using a method based on alkaline hydrolysis.

RESULTS

The content of hydroxyproline in the diabetic group was greater than that of control group (P < 0.05); we found significantly increased expression of TGF beta1 mRNA and bFGF mRNA in the bladder from the diabetic group compared with the control group; immunohistochemical and ELISA studies showed a statistically significant increased expression of TGF beta1 protein and bFGF protein in the bladder from the diabetic group compared with the control group (P < 0.05). The content of hydroxyproline in TAD group was less than that of diabetic group (P < 0.05); mRNA expression of TGF beta1 and bFGF greatly decreased in TAD group compared with that of the diabetic group; immunohistochemical and ELISA studies showed decreased levels of TGF beta1 protein and bFGF protein in the bladder from TAD group compared with the diabetic group (P < 0.05).

CONCLUSIONS

Rats with streptozoticin-induced diabetes mellitus showed significant increase in hydroxyproline, TGF beta1 and bFGF levels in their bladders, which may be an important mechanism inducing diabetic cystopathy. Tadenan could effectively reduce hydroxyproline, TGF beta1, and bFGF levels.

Basic fibroblast growth factor modulates proliferation and collagen expression in urinary bladder smooth muscle cells

Bladder hypertrophy is a general consequence of bladder outlet obstruction (BOO) and a typical phenomenon observed in clinical urologic diseases such as benign prostatic hyperplasia and neurogenic bladder. It is characterized by smooth muscle hyperplasia, altered extracellular matrix composition, and increased contractile function. Various growth factors are likely involved in hypertrophic pathophysiology, but their functions remain unknown. In this report, the role of basic fibroblast growth factor (bFGF) was investigated using a rat bladder smooth muscle cell (BSMC) culture system and an original animal model, in which bFGF was released from a gelatin hydrogel directly onto rat bladders. bFGF treatment promoted BSMC proliferation both in vitro and in vivo. In vitro, bFGF downregulated the expression of type I collagen, but upregulated type III collagen. ERK1/2, but not p38MAPK, was activated by bFGF, whereas inhibition of ERK1/2 by PD98059 reversed bFGF-induced BSMC proliferation, type I collagen downregulation, and type III collagen upregulation. In the in vivo release model, bFGF upregulated type III collagen and increased the contractile force of treated bladders. In parallel with these findings, hypertrophied rat bladders created by urethral constriction showed increased urothelial bFGF expression, BSMC proliferation, and increased type III collagen expression compared with sham-operated rats. These data suggest that bFGF from the urothelium could act as a paracrine signal that stimulates the proliferation and matrix production of BSMC, thereby contributing to the hypertrophic remodeling of the smooth muscle layer.

Role of transforming growth factor beta in rat bladder smooth muscle cell proliferation

Conditions associated with hypertrophy of the urinary bladder have repeatedly been associated with an increased urinary excretion of transforming growth factor (TGF) beta in both rats and patients. Because TGFbeta can have both growth-promoting and -inhibiting effects, we have studied its effects on cell growth and death in primary cultures of rat bladder smooth muscle cells. TGFbeta1, TGFbeta2, or TGFbeta3 did not cause apoptosis, but all three isoforms inhibited DNA synthesis with similar potency (EC(50) of approximately 0.1 ng/ml) and efficacy. Such inhibition was antagonized by a specific TGFbeta receptor antagonist and independent of the presence of serum. Mitogen-activated protein kinases (MAPKs) are involved in the control of cell growth, and all three TGFbeta isoforms inhibited activation of the extracellular signal-regulated kinase, c-Jun NH(2)-terminal kinase, and p38 MAPK subfamilies. Nevertheless, the inhibitory effects of the TGFbeta isoforms on DNA synthesis were not affected by presence of inhibitors of the three MAPK pathways. TGFbeta did not alter cell size as measured by flow cytometry or mitochondrial activity, an integrated measure of cell size and number. We conclude that our data do not support the hypothesis that TGFbeta is a mediator of rat bladder hypertrophy.

Developmental Changes of Col3a1 mRNA Expression in Muscle and Their Association with Intramuscular Collagen in Pigs

Eighty-four castrated boars including Laiwu Black (LW) (weight 30-90 kg, n=6) and Lulai Black (LL) (weight 40-100 kg, n=6) were used to study the developmental changes of collagen type III alpha 1 (Col3a1) mRNA expression in the muscle and their association with intramuscular collagen (IMC). The muscle total RNA was extracted to determine the abundance of Col3a1 mRNA using relative quantitative RT-PCR with beta-actin mRNA as the internal standard. The results indicated that the developmental patterns of muscle Col3a1 mRNA in LW and LL pigs were similar. The abundance of Col3a1 mRNA increased with body weight, but decreased a little at 70 kg and 80 kg phases for LW and LL, respectively. On the whole, the expression level of Col3a1 mRNA in muscle of LW was higher than that of LL (P<0.05). Correlation analysis showed that the expression of Col3a1 mRNA in muscle was positively correlated with total and insoluble IMC, but was negatively correlated with IMC solubility for LW pigs (P<0.01) and LL pigs (P<0.05), respectively. These results suggest that the muscle Col3a1 gene expression is affected by body weight and genotype and has important effect on IMC content and characteristics.