Role of nicotinic and estrogen signaling during experimental acute and chronic bladder inflammation

Morin-5'-Sulfonic Acid Sodium Salt (NaMSA) Attenuates Cyclophosphamide-Induced Histological Changes in Genitourinary Tract in Rats-Short Report

Cyclophosphamide (CPX) exerts toxicity in the urogenital system. The current study was designed to evaluate the effect of morin-5′-sulfonic acid sodium salt (NaMSA) on CPX-induced urogenital toxicity in rats. NaMSA (100 mg/kg/daily) and CPX (15 mg/kg/daily) alone or in combination and 0.9% NaCl (as a control) were given intragastrically for 10 days. Testes and epididymes from male and urinary bladders from male and female rats were evaluated histologically. In testes and epididymes, morphological changes and relative decrease in sperm count were assessed. In urinary bladders edema, hemorrhage and urothelium erosions were described by 0–2 points scoring system. Reproductive score (RS—in total 6 points) and urinary bladder score (BS—in total 6 points) were thereafter calculated. In CPX-receiving group RS (2.7) and BS (3.3) were significantly higher than in the control (0.5 and 0.25 for RS and BS, respectively). Co-administration of NaMSA reversed most of the morphological changes, which was reflected by lower RS and BS score (0.5 and 1.2 for RS and BS, respectively). The preliminary findings suggest that NaMSA may attenuate CPX-induced histological changes in rat urogenital tract.

Proliferation of the human urothelium is induced by atypical β1 -adrenoceptors

We wanted to assess whether β-adrenoceptors mediate proliferation in the normal and malignant urothelial cell lines UROtsa and T24, respectively. Urothelial cells were cultured for 24 h in the presence of the β-adrenoceptor agonists isoprenaline (β1/2/3 ), dobutamine (β1 ), salbutamol (β2 ), BRL 37344 (β3 ), CGP 12177 (a partial β-agonist) or β-adrenoceptor antagonists (metoprolol; β1 , propranolol; β1/2 ). Phosphorylation of kinases was screened with a Human Phospho-Kinase Array Kit (R&D systems). Intracellular pathways activated by proliferation of urothelial cells were characterized by incubating cells with the MEK1/2 inhibitor PD 98,059, the p38 kinase inhibitor losmapimod or with the Akt 1/2 kinase inhibitor. Proliferation was assessed with the MTT proliferation assay (ATCC). Western blot and immunocytochemistry were used for detection of the β1 -adrenoceptor. Isoprenaline and dobutamine induced proliferation, while salbutamol and BRL 37344 did not. Dobutamine-induced proliferation was not affected by metoprolol or propranolol but was instead antagonized by CGP 12177 in T24 but not in UROtsa. In response to stimulation with dobutamine, Akt1/2/3 was phosphorylated in UROtsa, while ERK1/2 and p38 were phosphorylated in T24. MEK1/2 inhibition blocked basal and dobutamine-induced proliferation in T24 but only basal proliferation in UROtsa. Losmapimod slightly inhibited basal proliferation in T24 but not dobutamine-induced proliferation. Akt 1/2 inhibitor blocked basal and dobutamine-induced proliferation in UROtsa. Immunocytochemistry and Western blot revealed expression of β1 -adrenoceptors in both urothelial cell lines. The present data show that the urothelium expresses atypical β1-adrenoceptors that activate intracellular kinases inducing urothelial proliferation.

Histone deacetylase inhibitors mediate DNA damage repair in ameliorating hemorrhagic cystitis

Hemorrhagic cystitis is an inflammatory and ulcerative bladder condition associated with systemic chemotherapeutics, like cyclophosphomide. Earlier, we reported reactive oxygen species resulting from cyclophosphamide metabolite, acrolein, causes global methylation followed by silencing of DNA damage repair genes. Ogg1 (8-oxoguanine DNA glycosylase) is one such silenced base excision repair enzyme that can restore DNA integrity. The accumulation of DNA damage results in subsequent inflammation associated with pyroptotic death of bladder smooth muscle cells. We hypothesized that reversing inflammasome-induced imprinting in the bladder smooth muscle could prevent the inflammatory phenotype. Elevated recruitment of Dnmt1 and Dnmt3b to the Ogg1 promoter in acrolein treated bladder muscle cells was validated by the pattern of CpG methylation revealed by bisulfite sequencing. Knockout of Ogg1 in detrusor cells resulted in accumulation of reactive oxygen mediated 8-Oxo-dG and spontaneous pyroptotic signaling. Histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), restored Ogg1 expression in cells treated with acrolein and mice treated with cyclophosphamide superior to the standard of care, mesna or nicotinamide-induced DNA demethylation. SAHA restored cyclophosphamide-induced bladder pathology to that of untreated control mice. The observed epigenetic imprinting induced by inflammation suggests a new therapeutic target for the treatment of hemorrhagic cystitis.

Pirt reduces bladder overactivity by inhibiting purinergic receptor P2X3

Pirt is a transmembrane protein predominantly expressed in peripheral neurons. However, the physiological and pathological roles of Pirt in hollow viscus are largely unknown. Here we show that Pirt deficiency in mice causes bladder overactivity. The density of α,β-meATP-induced currents is significantly reinforced in Pirt-deficient dorsal root ganglion (DRG) neurons. Pirt and P2X3 receptor co-localize in bladder nerve fibres and heterologous Pirt expression significantly reduces P2X3-mediated currents. Pirt interacts with P2X3 through the N-terminal 14 amino-acid residues. TAT-conjugated Pirt(N14) peptide (Pirt(N14)) is sufficient to inhibit P2X3 activation in bladder DRG neurons and to alleviate bladder overactivity in Pirt(-/-) mice. Pirt expression is decreased in the bladder of cyclophosphamide (CYP)-treated mice, a commonly used model of bladder overactivity. Importantly, Pirt(N14) administration reduces the frequency of bladder voiding and restores the voided volume of CYP-treated mice. Therefore, our results demonstrate that Pirt is an endogenous regulator of P2X3 in bladder function.

Inflammation and pyroptosis mediate muscle expansion in an interleukin-1β (IL-1β)-dependent manner

Muscle inflammation is often associated with its expansion. Bladder smooth muscle inflammation-induced cell death is accompanied by hyperplasia and hypertrophy as the primary cause for poor bladder function. In mice, DNA damage initiated by chemotherapeutic drug cyclophosphamide activated caspase 1 through the formation of the NLRP3 complex resulting in detrusor hyperplasia. A cyclophosphamide metabolite, acrolein, caused global DNA methylation and accumulation of DNA damage in a mouse model of bladder inflammation and in cultured bladder muscle cells. In correlation, global DNA methylation and NLRP3 expression was up-regulated in human chronic bladder inflammatory tissues. The epigenetic silencing of DNA damage repair gene, Ogg1, could be reversed by the use of demethylating agents. In mice, demethylating agents reversed cyclophosphamide-induced bladder inflammation and detrusor expansion. The transgenic knock-out of Ogg1 in as few as 10% of the detrusor cells tripled the proliferation of the remaining wild type counterparts in an in vitro co-culture titration experiment. Antagonizing IL-1β with Anakinra, a rheumatoid arthritis therapeutic, prevented detrusor proliferation in conditioned media experiments as well as in a mouse model of bladder inflammation. Radiation treatment validated the role of DNA damage in the NLRP3-associated caspase 1-mediated IL-1β secretory phenotype. A protein array analysis identified IGF1 to be downstream of IL-1β signaling. IL-1β-induced detrusor proliferation and hypertrophy could be reversed with the use of Anakinra as well as an IGF1 neutralizing antibody. IL-1β antagonists in current clinical practice can exploit the revealed mechanism for DNA damage-mediated muscular expansion.

Assay of lapatinib in murine models of cigarette smoke carcinogenesis

Lapatinib, a dual tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2), is prescribed for the treatment of patients with metastatic breast cancer overexpressing HER-2. Involvement of this drug in pulmonary carcinogenesis has been poorly investigated. We used murine models suitable to evaluate cigarette smoke-related molecular and histopathological alterations. A total of 481 Swiss H mice were used. The mice were exposed to mainstream cigarette smoke (MCS) during the first four months of life. After 10 weeks, MCS caused an elevation of bulky DNA adducts, oxidative DNA damage and an extensive downregulation of microRNAs in lung. After four months, an increase in micronucleus frequency was observed in peripheral blood erythrocytes. After 7.5 months, histopathological alterations were detected in the lung, also including benign tumors and malignant tumors, and in the urinary tract. A subchronic toxicity study assessed the non-toxic doses of lapatinib, administered daily with the diet after weaning. After 10 weeks, lapatinib significantly attenuated the MCS-related nucleotide changes and upregulated several low-intensity microRNAs in lung. The drug poorly affected the MCS systemic genotoxicity and had modest protective effects on MCS-induced preneoplastic lesions in lung and kidney, when administered under conditions that temporarily mimicked interventions either in current smokers or ex-smokers. On the other hand, it caused some toxicity to the liver. Thus, on the whole, lapatinib appears to have a low impact in the smoke-related lung carcinogenesis models used, especially in terms of tumorigenic response.

Modulation by metformin of molecular and histopathological alterations in the lung of cigarette smoke-exposed mice

The anti-diabetic drug metformin is endowed with anti-cancer properties. Epidemiological and experimental studies, however, did not provide univocal results regarding its role in pulmonary carcinogenesis. We used Swiss H mice of both genders in order to detect early molecular alterations and tumors induced by mainstream cigarette smoke. Based on a subchronic toxicity study, oral metformin was used at a dose of 800 mg/kg diet, which is 3.2 times higher than the therapeutic dose in humans. Exposure of mice to smoke for 4 months, starting at birth, induced a systemic clastogenic damage, formation of DNA adducts, oxidative DNA damage, and extensive downregulation of microRNAs in lung after 10 weeks. Preneoplastic lesions were detectable after 7.5 months in both lung and urinary tract along with lung tumors, both benign and malignant. Modulation by metformin of 42 of 1281 pulmonary microRNAs in smoke-free mice highlighted a variety of mechanisms, including modulation of AMPK, stress response, inflammation, NFκB, Tlr9, Tgf, p53, cell cycle, apoptosis, antioxidant pathways, Ras, Myc, Dicer, angiogenesis, stem cell recruitment, and angiogenesis. In smoke-exposed mice, metformin considerably decreased DNA adduct levels and oxidative DNA damage, and normalized the expression of several microRNAs. It did not prevent smoke-induced lung tumors but inhibited preneoplastic lesions in both lung and kidney. In conclusion, metformin was able to protect the mouse lung from smoke-induced DNA and microRNA alterations and to inhibit preneoplastic lesions in lung and kidney but failed to prevent lung adenomas and malignant tumors induced by this complex mixture.

F2-isoprostanes as a biomarker of oxidative stress in the mouse bladder

PURPOSE

We theorized that progressive bladder dysfunction due to clinical diagnoses such as outlet obstruction occurs as a result of cyclical oxidative stress events. We hypothesized that measurement of F2-isoprostane, a marker of lipid peroxidation, could serve as a biomarker of oxidative stress in the murine bladder.

MATERIALS AND METHODS

At age 5 to 6 weeks oophorectomized female mice were subjected to 1 of 2 bladder injury models, that is partial bladder outlet obstruction or acute bladder distension. The time points studied after injury included 4, 8 and 16 weeks after obstruction, and 0 to 48 hours after acute bladder distension. In a separate group short-term repetitive acute bladder distension was performed every other day for 14 days. Bladder samples were analyzed for F2-isoprostane using gas chromatography and mass spectroscopy. Mean tissue F2-isoprostane levels were compared.

RESULTS

F2-isoprostane increased significantly after 4 weeks of partial bladder outlet obstruction from 1.46 ng/gm in controls to 2.31 ng/gm at 4 weeks (p = 0.01). Eight and 16 weeks after partial bladder outlet obstruction F2-isoprostane remained significantly elevated (2.39 and 2.48 ng/gm, respectively). Acute bladder distension resulted in a significant increase in F2-isoprostane immediately after distension compared to controls (1.6 vs 0.75 ng/gm, p = 0.04). In mice that underwent repetitive acute bladder distension F2-isoprostane did not change.

CONCLUSIONS

Measurement of tissue F2-isoprostane in the bladder reflects the progression of oxidative stress, primarily in chronic injury models such as partial bladder outlet obstruction. The usefulness of F2-isoprostane measurements in shorter term injury models requires further study.

Epigenetically modulated LRRC33 acts as a negative physiological regulator for multiple Toll-like receptors

The members of a LRR family play crucial roles in the activation of innate and adaptive immune responses. We reported previously that LRRC33, a transmembrane protein of the LRR family, might potentially affect TLR-mediated activity. Here, we demonstrate that LRRC33 is a negative physiological regulator for multiple TLRs. Lrrc33(-/-) and Lrrc33(+/-) mice were more susceptible to TLR ligand challenges. The macrophages and DCs from Lrrc33(-/-) mice produced more proinflammatory cytokines than those of WT mice through increased activation of MAPK and NF-κB. Silencing LRRC33 also promoted multiple TLR-mediated activation in human moDCs. Notably, LRRC33 expression could be down-regulated by TLR ligands LPS, poly I:C, or PGN through H3K4me3 and H3K27me3 modification. In LPS-conditioned moDCs, reduced enrichment of H3K4me3 and increased H3K27me3 could be observed at the promoter region of LRRC33. Furthermore, silencing H3K4me3-associated factors MLL and RBBP5 not only decreased the enrichment of H3K4me3 but also down-regulated expression of LRRC33, whereas the expression of LRRC33 was up-regulated after silencing H3K27me3-associated factors EZH2 and EED. Thus, our results suggest that LRRC33 and TLRs may form a negative-feedback loop, which is important for the maintenance of immune homeostasis.

Clinical significance of yes-associated protein overexpression in cervical carcinoma: the differential effects based on histotypes

OBJECTIVES

The objective of this study was to explore the prognostic values of Yes-associated protein (YAP) expression in cervical carcinoma.

METHODS

We compared the YAP expression of 120 samples from squamous cell carcinomas (SCCs) and 42 samples from adenocarcinomas with 22 normal cervical specimens by immunohistochemistry. The expressions of cytoplasmic and nuclear YAP were analyzed separately.

RESULT

Yes-associated protein expression in tumors is significantly higher than the level in normal tissues. In SCCs, cytoplasmic YAP expression is associated with histologic grading, lymph node metastasis, and recurrence. Nuclear expression of YAP is absent in SCC. In adenocarcinomas, cytoplasmic YAP overexpression is associated with histologic grading, and nuclear overexpression is associated with shorter overall survival and disease-free survival.

CONCLUSIONS

Our results indicate the oncogenic potential of YAP in cervical cancer and its distinct functions in SCC and adenocarcinoma.

Alterations in deoxyribonucleic acid (DNA) methylation patterns of Calca, Timp3, Mmp2, and Igf2r are associated with chronic cystitis in a cyclophosphamide-induced mouse model

OBJECTIVE

To determine whether epigenetic changes occur during cyclophosphamide-induced chronic bladder inflammation in mice.

MATERIALS AND METHODS

Epigenetic changes play a role in the regulation of inflammatory genes in noncancer diseases such as asthma and chronic obstructive pulmonary disease. However, epigenetic (deoxyribonucleic acid [DNA] methylation) changes during chronic bladder inflammation have not been previously described. Chronic cystitis was induced in 3 groups of adult CD-1 male mice using multiple weight-based intraperitoneal cyclophosphamide injections during a 3-month period. Histopathologic and MethyLight assays were performed on specimens with chronic bladder inflammation at multiple points to monitor cystitis progression and DNA methylation changes compared with the control specimens.

RESULTS

Histopathologic analysis showed the most extensive edema and urothelial sloughing at the 1-month point. MethyLight analyses revealed statistically significant changes in DNA methylation associated with the Calca, Timp3, Mmp2, and Igf2r genes in the chronic bladder injury model. The changes in DNA methylation associated with chronic cystitis were DNA hypomethylation of the Calca gene in the control tissue and DNA hypermethylation for the Calca, Timp3, Mmp2, and Igf2r genes compared with that in the control tissue.

CONCLUSION

DNA methylation changes were noted in the Calca, Timp3, Mmp2, and Igf2r genes during chronic cystitis in a murine model. Epigenetic changes appear to play a role in the regulation of inflammatory bladder genes during chronic cystitis; however, additional studies are needed to elucidate the pathways associated with these genes.

Role of oestrogen receptors in bladder cancer development

Early studies documented the existence of sexual dimorphism in bladder cancer occurrence and progression, with a greater bladder cancer incidence in males than females. However, the progression of bladder cancer after diagnosis is much quicker in females than males. These findings can be explained by the effects of female hormones (predominantly oestrogens) and their binding receptors, including oestrogen receptor 1 (ESR1; also known as ERα), oestrogen receptor 2 (ESR2; also known as ERβ), and GPR30 protein on bladder cancer incidence and progression. Results from studies using various in vitro cell lines and in vivo mouse models demonstrate differential roles of oestrogen receptors in cancer initiation and progression. ERα suppresses bladder cancer initiation and invasion, whereas ERβ promotes bladder cancer initiation and progression. Mechanistic studies suggest that ERα and ERβ exert these effects via modulation of the AKT pathway and DNA replication complex, respectively. Targeting these signalling pathways--for example, with ERα agonists, ERβ antagonists, or selective oestrogen receptor modulators such as 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl]phenol (also known as PHTPP)--could lead to the development of new therapeutic approaches for controlling bladder cancer progression.

Lipocalin-2 gene expression during liver regeneration after partial hepatectomy in rats

BACKGROUND

Lipocalin-2 (Lcn2) is related to cell proliferation. We studied Lcn2 gene expression during liver regeneration after partial hepatectomy (PH).

METHODS

Male Wistar rats were sacrificed before and 2, 4, 6, 12, 24, 72 h, 7 days after 70% or 40% PH. The remnant liver weight/body weight (RLW/BW) ratio, Lcn2 gene and mRNA expression in the remnant livers were measured. Hepatocytes and nonparenchymal cells were isolated from the remnant livers. Expression of Lcn2 related protein was detected by Western blot.

RESULTS

The RLW/BW ratio increased to nearly 90% of the original liver 72 h after PH. Lcn2 gene expression showed upward curves from 4 to 72 h after PH in both 70% and 40% PH rats and peaked at 12 h (8 times vs 0 h). Lcn2 mRNA expression showed parallel upward curves from 2 to 72 h. The peak was significantly higher in 70% PH rats (2(7) times vs 0 h) than in 40% PH rats (2(5) times vs 0 h) 12 h after PH (p < 0.05). Lcn2 related protein in the isolated liver cells was markedly enhanced 24 h after PH, more in hepatocytes than in nonparenchymal cells.

CONCLUSION

The expressions of Lcn2 gene and mRNA, and its related protein increased markedly after PH. Lcn2 might be important in the genetic regulation of liver regeneration after PH.

Chronic cyclic bladder over distention up-regulates hypoxia dependent pathways

PURPOSE

Bladder over distention secondary to anatomical or functional obstruction can eventually lead to pathological changes, including decreased elasticity and contractile dysfunction. We hypothesized that chronic bladder distention in a murine model would activate hypoxia dependent signaling pathways despite intermittent relief of distention.

MATERIALS AND METHODS

Female C57Bl/6 mice were oophorectomized at age 5 to 6 weeks and underwent urethral catheterization and 90-minute bladder distention. Acute and chronic time points were evaluated. Bladder tissue was harvested for hematoxylin and eosin, and immunohistochemical staining with the hypoxia markers Glut-1 (EMD Millipore, Merck, Darmstadt, Germany) and Hypoxyprobe™-1. Bladder tissue was also harvested for real-time polymerase chain reaction and oxidative stress measurement. Hypoxia polymerase chain reaction arrays were done to determine changes in gene expression. Oxidative stress was measured using F2-IsoP. Functional bladder changes were evaluated using voided urine blots.

RESULTS

After acute distention and 5 consecutive distentions, bladders showed marked inflammatory changes on hematoxylin and eosin staining, and evidence of tissue hypoxia on immunohistochemistry. Quantitative real-time polymerase chain reaction revealed up-regulation of hypoxia and oxidative stress related genes, including Hif1a, Arnt2, Ctgf, Gpx1 and Hmox1. Measurements of oxidative stress with F2-IsoP did not change. Voided urine blots before and after bladder distention showed marked changes with an overactive voiding pattern.

CONCLUSIONS

Chronic bladder distention is possible in the female mouse. It generates hypoxic injury, as characterized functionally by increased voiding patterns. This bladder injury model might more closely replicate bladder dysfunction in patients with poor bladder emptying due to neurological disease, including those noncompliant with intermittent catheterization.

DNA damage in exfoliated cells and histopathological alterations in the urinary tract of mice exposed to cigarette smoke and treated with chemopreventive agents

Cigarette smoke (CS) is convincingly carcinogenic in mice when exposure starts at birth. We investigated the induction and modulation of alterations in the kidney and urinary bladder of CS-exposed mice. A total of 484 strain H Swiss mice were either sham-exposed or exposed since birth to mainstream CS (MCS) for 4 months. Dietary agents, including myo-inositol, suberoylanilide hydroxamic acid, bexarotene, pioglitazone and a combination of bexarotene and pioglitazone, were administered after weaning. Comet analyses showed that, after 2 and 4 months, MCS causes DNA damage in exfoliated urothelial cells, which can be prevented by myo-inositol and the peroxisome proliferator-activated receptor-γ ligand pioglitazone. After 7 months, the 17.6% of MCS-exposed male mice exhibited lesions of the urinary tract versus the 6.1% of sham-exposed mice, which emphasizes the role of sex hormones in urinary tract carcinogenesis. Myo-inositol and the RXR-specific retinoid bexarotene did not affect these alterations. The histone deacetylase inhibitor suberoylanilide hydroxamic acid (Vorinostat) increased the incidence of kidney epithelium hyperplasia. Pioglitazone significantly enhanced the incidence of kidney lesions as compared with mice exposed to MCS only, indicating possible adverse effects of this antidiabetic drug, which were lost upon combination with bexarotene according to a combined chemoprevention strategy. RXR is a heterodymeric partner for peroxisome proliferator-activated receptor-γ, thereby modulating the expression of multiple target genes. In conclusion, there is contrast between the ability of pioglitazone to inhibit DNA damage in exfoliated cells and the alterations induced in the urinary tract of MCS-exposed mice, suggesting the occurrence of non-genotoxic mechanisms for this drug.

Modulation of the hypoxic response following partial bladder outlet obstruction

PURPOSE

Tissue level hypoxia has been noted in animal models of partial bladder outlet obstruction. The key mechanisms linking hypoxia and obstruction induced bladder dysfunction remain unknown. 2-Methoxyestradiol is a natural derivative of 17β-estradiol and is currently used as an oncologic agent for its ability to regulate the hypoxia pathway. We investigated the ability of 2-methoxyestradiol to modulate the hypoxia response in a mouse model of bladder obstruction.

MATERIALS AND METHODS

A group of 5 to 6-week-old female C57BL/6 mice underwent oophorectomy and partial bladder outlet obstruction. Obstructed animals received a subcutaneous pellet of cholesterol placebo (7) or 2-methoxyestradiol plus cholesterol (7). Age matched controls underwent oophorectomy only (8). After 4 weeks the bladders of mice with partial bladder outlet obstruction and of unobstructed animals were harvested. Bladder sections (5 μm) were immunostained for Hypoxyprobe™-1, glucose transporter 1 and hypoxia inducible factor-1α. Real-time polymerase chain reaction was performed for hypoxia inducible factor-1α and lysyl oxidase. Statistical analysis was performed using 1-way ANOVA and the Wilcoxon rank sum test.

RESULTS

Immunostaining for glucose transporter 1 and Hypoxyprobe-1 revealed the presence of tissue hypoxia after partial bladder outlet obstruction. Immunostaining and real-time polymerase chain reaction demonstrated the up-regulation of hypoxia inducible factor-1α in mice after partial bladder outlet obstruction compared to controls (p = 0.0394). Although not statistically significant, a trend toward lower gene expression of hypoxia inducible factor-1α was seen in mice receiving 2-methoxyestradiol compared to placebo (p = 0.0625). Compared to placebo, 2-methoxyestradiol treatment increased lysyl oxidase expression (p = 0.007).

CONCLUSIONS

Murine partial bladder outlet obstruction resulted in hypoxia and up-regulation of the hypoxia inducible factor-1 pathway. Subcutaneous 2-methoxyestradiol administration attenuated this response and may be a viable tool to study the role of hypoxia after partial bladder outlet obstruction.

Molecular imaging of nuclear factor-κB in bladder as a primary regulator of inflammatory response

PURPOSE

Nuclear factor-κB activation is implicated in chronic inflammatory disorders and it is a key regulator of genes involved in the response to infection, inflammation and stress. Interstitial cystitis and painful bladder syndrome are common inflammatory disorders of the bladder characterized by frequent urination and bladder pain. The role of nuclear factor-κB activation in bladder inflammation is not well defined.

MATERIALS AND METHODS

Female transgenic nuclear factor-κB-luciferase Tag mice (The Jackson Laboratory, Bar Harbor, Maine) were used to perform serial, noninvasive in vivo and ex vivo molecular imaging of nuclear factor-κB activation in the whole body after administering arsenic trioxide (5 mg/kg), lipopolysaccharide (2 mg/kg) or cyclophosphamide (Sigma®) (200 mg/kg) to initiate acute transient bladder inflammation. Pretreatment with dexamethasone (Sigma) (10 mg/kg) was used to modulate cyclophosphamide induced nuclear factor-κB dependent luminescence in vivo.

RESULTS

Treatment of nuclear factor-κB-luciferase Tag mice with chemicals increased luminescence in a time and organ specific manner in vivo and ex vivo. The highest levels of bladder nuclear factor-κB dependent luminescence were observed 4 hours after cyclophosphamide administration. Pretreatment with dexamethasone 1 hour before cyclophosphamide injection significantly down-regulated cyclophosphamide induced bladder nuclear factor-κB dependent luminescence, ameliorated the grossly evident pathological features of acute inflammation and decreased cellular immunostaining for nuclear factor-κB in the bladder.

CONCLUSIONS

Nuclear factor-κB activity may have an important role in the pathophysiology of bladder inflammation. Nuclear factor-κB-luciferase mice can serve as a useful model in which to screen potential candidate drugs for cystitis associated with aberrant nuclear factor-κB activity. Such screening may significantly aid the development of therapeutic strategies to manage inflammatory bladder disorders.

Yes-associated protein expression in head and neck squamous cell carcinoma nodal metastasis

Introduction

Yes-associated protein (YAP) is considered an oncogene found amplified in multiple tumors, including head and neck squamous cell carcinoma (HNSCC). However, the role for YAP expression in HNSCC is not understood. Based on the central role of YAP in the hippo pathway, we tested if YAP was associated with the stage of HNSCC progression and metastatic potential.

Methods

To determine the expression of YAP in human benign and HNSCC tissue specimens, immunohistochemical analyses were performed in whole tissue samples and tissue microarrays. The expression of YAP in tissues of microarray was first associated with clinic-pathologic factors and results verified in samples from whole tissue sections. To investigate the role of YAP and p63 in regulating HNSCC epithelial to mesenchymal transition, epithelial and mesenchymal markers were assayed in Fadu and SCC-25 cells, HNSCC cells with endogenously elevated YAP expression and siRNA-mediated expression knockdown.

Results

Analysis of human HNSCC tissues suggested YAP expression was elevated in tumors compared to benign tissues and specifically localized at the tumor invasive front (p value <0.05). But, indexed YAP expression was lower with greater tumor grade (p value  = 0.02). In contrast, p63 expression was primarily elevated in high-grade tumors. Interestingly, both YAP and p63 was strongly expressed at the tumor invasive front and in metastatic HNSCC. Strikingly, we demonstrated YAP expression in the primary HNSCC tumor was associated with nodal metastasis in univariate analysis (p value  = 0.02). However, the knockdown of YAP in Fadu and SCC-25 cell lines was not associated with changes in epithelial to mesenchymal transdifferentiation or p63 expression.

Conclusion

Together, YAP expression, in combination with p63 can facilitate identification of HNSCC tumors from hyperplastic and benign tissues and the metastatic function of YAP in HNSCC may not be a result of epithelia to mesenchymal transdifferentiation.

Mesenchymal stem cell recruitment and improved bladder function after bladder outlet obstruction: preliminary data

PURPOSE

Mesenchymal stem cells have various therapeutic benefits in various organ injury models. Bladder outlet obstruction causes smooth muscle hypertrophy and fibrosis, leading to lowered compliance, increased storage pressures and renal injury. Decreased blood flow and hypoxia may contribute to obstruction related bladder decompensation. We used a mouse model to determine whether mesenchymal stem cell recruitment occurred after bladder outlet obstruction and whether this was associated with changes in bladder hypoxia, histology and function. We also identified potential chemokines involved in mesenchymal stem cell recruitment.

MATERIALS AND METHODS

A total of 20 female mice underwent bladder outlet obstruction. Three days later 2 million green fluorescent protein labeled mesenchymal stem cells were intravenously administered. After 4 weeks urodynamic and histological evaluation was performed. Quantitative reverse transcriptase-polymerase chain reaction was done to determine relative expression of the chemokines CCL2, CCL20, CCL25, CXCL9 and CXCL16. We simultaneously studied mice with bladder outlet obstruction only without mesenchymal stem cell injection and a control group.

RESULTS

In 10 of 15 surviving mesenchymal stem cell injected mice mesenchymal stem cells were identified in the detrusor, and decreased hypoxia, hypertrophy and fibrosis was seen. Nine of 10 mice with mesenchymal stem cell engraftment had improved compliance compared to those without engraftment (mean±SD 9.6±5.1 vs 3.9±2.6 μl/cm H2O, p=0.012). Polymerase chain reaction revealed a 2-fold increase in CCL2 expression but there were no significant changes in other chemokine levels.

CONCLUSIONS

Mesenchymal stem cell recruitment to the bladder after bladder outlet obstruction appears to be associated with increased blood flow and decreased tissue hypoxia, which may contribute to improvement in histopathological and functional parameters. Mesenchymal stem cell recruitment may be related to CCL2 over expression. Additional studies in larger samples are needed but these initial results suggest a potential role for mesenchymal stem cell based therapy for bladder outlet obstruction related bladder injury.

Alpha7 nicotinic receptors as novel therapeutic targets for inflammation-based diseases

In recent years the etiopathology of a number of debilitating diseases such as type 2 diabetes, arthritis, atherosclerosis, psoriasis, asthma, cystic fibrosis, sepsis, and ulcerative colitis has increasingly been linked to runaway cytokine-mediated inflammation. Cytokine-based therapeutic agents play a major role in the treatment of these diseases. However, the temporospatial changes in various cytokines are still poorly understood and attempts to date have focused on the inhibition of specific cytokines such as TNF-α. As an alternative approach, a number of preclinical studies have confirmed the therapeutic potential of targeting alpha7 nicotinic acetylcholine receptor-mediated anti-inflammatory effects through modulation of proinflammatory cytokines. This "cholinergic anti-inflammatory pathway" modulates the immune system through cholinergic mechanisms that act on alpha7 receptors expressed on macrophages and immune cells. If the preclinical findings translate into human efficacy this approach could potentially provide new therapies for treating a broad array of intractable diseases and conditions with inflammatory components.

Dermal transforming growth factor-beta responsiveness mediates wound contraction and epithelial closure

Stromal-epithelial interactions are important during wound healing. Transforming growth factor-beta (TGF-beta) signaling at the wound site has been implicated in re-epithelization, inflammatory infiltration, wound contraction, and extracellular matrix deposition and remodeling. Ultimately, TGF-beta is central to dermal scarring. Because scarless embryonic wounds are associated with the lack of dermal TGF-beta signaling, we studied the role of TGF-beta signaling specifically in dermal fibroblasts through the development of a novel, inducible, conditional, and fibroblastic TGF-beta type II receptor knockout (Tgfbr2(dermalKO)) mouse model. Full thickness excisional wounds were studied in control and Tgfbr2(dermalKO) back skin. The Tgfbr2(dermalKO) wounds had accelerated re-epithelization and closure compared with controls, resurfacing within 4 days of healing. The loss of TGF-beta signaling in the dermis resulted in reduced collagen deposition and remodeling associated with a reduced extent of wound contraction and elevated macrophage infiltration. Tgfbr2(dermalKO) and control skin had similar numbers of myofibroblastic cells, suggesting that myofibroblastic differentiation was not responsible for reduced wound contraction. However, several mediators of cell-matrix interaction were reduced in the Tgfbr2(dermalKO) fibroblasts, including alpha1, alpha2, and beta1 integrins, and collagen gel contraction was diminished. There were associated deficiencies in actin cytoskeletal organization of vasodilator-stimulated phosphoprotein-containing lamellipodia. This study indicated that paracrine and autocrine TGF-beta dermal signaling mechanisms mediate macrophage recruitment, re-epithelization, and wound contraction.

Recruitment of bone marrow derived cells to the bladder after bladder outlet obstruction

PURPOSE

Bladder fibrosis is an undesired end point of partial bladder outlet obstruction. In fibrotic disease of the lung, kidney, skin and heart chemokines recruit bone marrow derived cells to injured tissue. Blockade of chemokines like CCL2 results in decreased fibrosis in other organs. To our knowledge we present the first report of bone marrow derived cell recruitment to the bladder in a murine bladder outlet obstruction model.

MATERIALS AND METHODS

We lethally irradiated WT female mice and reconstituted their bone marrow using fetal liver cells from transgenic mice ubiquitously expressing green fluorescent protein. Periurethral collagen injection was used for bladder outlet obstruction. Obstruction was assessed by urodynamics, and bladder and kidney histological changes. Bladders were harvested 1 to 12 weeks after bladder outlet obstruction and compared to those in nonobstructed controls. The chemokine CCL2 was compared between obstructed and nonobstructed mice with reverse transcriptase-polymerase chain reaction. Green fluorescent protein expressing bone marrow derived cells were identified with immunohistochemistry and fluorescence activated cell sorting.

RESULTS

Bladders showed histological and urodynamic changes consistent with obstruction. CCL2 induction increased after obstruction compared to that in controls. After obstruction bone marrow derived cells were present in the urothelial and stromal layers. Activated epidermal growth factor receptor was found in cells associated with bone marrow derived cells.

CONCLUSIONS

Bone marrow derived cells are recruited to the bladder by bladder outlet obstruction and are present in the urothelial and stromal layers. Stromal bone marrow derived cells may have a role in hypertrophy and fibrosis. Further study of the recruitment and function of bone marrow derived cells in the bladder may provide potential targets for antifibrotic therapy.