Tatsuya Ihara

Clock Genes Regulate the Circadian Expression of Piezo1, TRPV4, Connexin26, and VNUT in an Ex Vivo Mouse Bladder Mucosa

Objectives ClockΔ19/Δ19 mice is an experimental model mouse for nocturia (NOC). Using the bladder mucosa obtained from ClockΔ19/Δ19 mice, we investigated the gene expression rhythms of mechanosensory cation channels such as transient receptor potential cation channel subfamily V member 4 (TRPV4) and Piezo1, and main ATP release pathways including vesicular nucleotide transporter (VNUT) and Connexin26(Cx26), in addition to clock genes. Materials and methods Eight- to twelve-week-old male C57BL/6 mice (WT) and age- and sex-matched C57BL/6 ClockΔ19/Δ19 mice, which were bred under 12-h light/dark conditions for 2 weeks, were used. Gene expression rhythms and transcriptional regulation mechanisms in clock genes, mechanosensor, Cx26 and VNUT were measured in the mouse bladder mucosa, collected every 4 hours from WT and ClockΔ19/Δ19 mice using quantitative RT-PCR, a Western blot analysis, and ChIP assays. Results WT mice showed circadian rhythms in clock genes as well as mechanosensor, Cx26 and VNUT. Their expression was low during the sleep phase. The results of ChIP assays showed Clock protein binding to the promotor regions and the transcriptional regulation of mechanosensor, Cx26 and VNUT. In contrast, all of these circadian expressions were disrupted in ClockΔ19/Δ19 mice. The gene expression of mechanosensor, Cx26 and VNUT was maintained at a higher level in spite of the sleep phase. Conclusions Mechanosensor, Cx26 and VNUT expressed with circadian rhythm in the mouse bladder mucosa. The disruption of circadian rhythms in these genes, induced by the abnormalities in clock genes, may be factors contributing to NOC because of hypersensitivity to bladder wall extension.

The Clock mutant mouse is a novel experimental model for nocturia and nocturnal polyuria.

The pathophysiologies of nocturia (NOC) and nocturnal polyuria (NP) are multifactorial and their etiologies remain unclear in a large number of patients. Clock genes exist in most cells and organs, and the products of Clock regulate circadian rhythms as representative clock genes. Clock genes regulate lower urinary tract function, and a newly suggested concept is that abnormalities in clock genes cause lower urinary tract symptoms. In the present study, we investigated the voiding behavior of Clock mutant (ClockΔ19/Δ19) mice in order to determine the effects of clock genes on NOC/NP.

The oscillation of intracellular Ca 2+ influx associated with the circadian expression of Piezo1 and TRPV4 in the bladder urothelium

We previously showed that bladder functions are controlled by clock genes with circadian rhythm. The sensation of bladder fullness (SBF) is sensed by mechano-sensor such as Piezo1 and TRPV4 in the mouse bladder urothelium. However, functional circadian rhythms of such mechano-sensors remain unknown. To investigate functional circadian changes of these mechano-sensors, we measured circadian changes in stretch-evoked intracellular Ca2+ influx ([Ca2+]i) using mouse primary cultured urothelial cells (MPCUCs). Using Ca2+ imaging, stretch-evoked [Ca2+]i was quantified every 4 h in MPCUCs derived from wild-type (WT) and ClockΔ19/Δ19 mice, which showed a nocturia phenotype. Furthermore, a Piezo1 inhibitor GsMTx4 and a TRPV4 inhibitor Ruthenium Red were applied and stretch-evoked [Ca2+]i in MPCUCs was measured to investigate their contribution to SBF. Stretch-evoked [Ca2+]i showed a circadian rhythm in the WT mice. In contrast, ClockΔ19/Δ19 mice showed disrupted circadian rhythm. The administration of both GsMTx4 and Ruthenium Red eliminated the circadian rhythm of stretch-evoked [Ca2+]i in WT mice. We conclude that SBF may have a circadian rhythm, which is created by functional circadian changes of Piezo1 and TRPV4 being controlled by clock genes to be active during wakefulness and inactive during sleep. Abnormalities of clock genes disrupt SBF, and induce nocturia.

Tuberculous Granuloma in the Scrotal Skin After Intravesical Bacillus Calmette-Guerin Therapy for Bladder Cancer: A Case Report

Rare cases of tuberculous urinary tract or genital infection caused by intravesical Intravesical Bacillus Calmette-Guerin (BCG) instillation therapy have been reported. We encountered a patient with tuberculous granuloma in the scrotal skin after intravesical BCG therapy for bladder cancer. There was evidence of infection in the scrotal skin, but not in the epididymis. To the best of our knowledge, this is the first report of tuberculous granuloma in the scrotal skin without epididymitis after intravesical BCG therapy. In our case, lower urinary tract symptoms such as the terminal dribbling of urine appear to support the theory of direct BCG inoculation.

AMPK Suppresses Connexin43 Expression in the Bladder and Ameliorates Voiding Dysfunction in Cyclophosphamide-induced Mouse Cystitis.

Bladder voiding dysfunction is closely related to local oxidation, inflammation, and enhanced channel activities. Given that the AMP-activated protein kinase (AMPK) has anti-oxidative, anti-inflammatory and channel-inhibiting properties, we examined whether and how AMPK affected bladder activity. AMPK activation in rat bladder smooth muscle cells (BSMCs) using three different AMPK agonists resulted in a decrease in connexin43 (Cx43) expression and function, which was associated with reduced CREB phosphorylation, Cx43 promoter activity and mRNA expression, but not Cx43 degradation. Downregulation of CREB with siRNA increased Cx43 expression. A functional analysis revealed that AMPK weakened BSMC contraction and bladder capacity. AMPK also counteracted the IL-1β- and TNFα-induced increase in Cx43 in BSMCs. In vivo administration of the AMPK agonist AICAR attenuated cyclophosphamide-initiated bladder oxidation, inflammation, Cx43 expression and voiding dysfunction. Further analysis comparing the responses of the wild-type (Cx43+/+) and heterozygous (Cx43+/−) Cx43 mice to cyclophosphamide revealed that the Cx43+/− mice retained a relatively normal micturition pattern compared to the Cx43+/+ mice. Taken together, our results indicate that AMPK inhibits Cx43 in BSMCs and improves bladder activity under pathological conditions. We propose that strategies that target AMPK can be developed as novel therapeutic approaches for treating bladder dysfunction.

The Circadian expression of Piezo1, TRPV4, Connexin26, and VNUT, associated with the expression levels of the clock genes in mouse primary cultured urothelial cells

To investigate circadian gene expressions in the mouse bladder urothelium to establish an experimental model and study the functions of the circadian rhythm.

Metabolomics approach for male lower urinary tract symptoms: An identification of possible biomarkers and potential targets for new treatments

Purpose: We identified metabolites using a metabolomics approach and investigated the association between these metabolites and lower urinary tract symptoms. Materials and Methods: We used a 24‐hour bladder diary and I‐PSS (International Prostate Symptom Score) to assess micturition behavior and lower urinary tract symptoms in 58 male patients without apparent neurological disease. Lower urinary tract symptoms were defined as a total I‐PSS score of 8 or greater. Patients with a score of 7 or less were placed in the control group. A comprehensive study of plasma metabolites was also performed by capillary electrophoresis time‐of‐flight mass spectrometry. Metabolites were compared between the lower urinary tract symptoms and control groups using the Mann‐Whitney U test. Biomarkers of male lower urinary tract symptoms from the metabolites were analyzed using multivariable logistic regression analysis to determine the OR. Results: Of the 58 men 32 were in the lower urinary tract symptoms group and the remaining 26 were in the control group. The 24‐hour bladder diary showed that nocturnal urine volume, 24‐hour micturition frequency, nocturnal micturition frequency and the nocturia index were significantly higher in the lower urinary tract symptoms group. Metabolomics analysis identified 60 metabolites from patient plasma. Multivariate analysis revealed that increased glutamate and decreased arginine, asparagine and inosine monophosphate were significantly associated with lower urinary tract symptoms in males. Decreases in citrulline and glutamine could also be associated with male lower urinary tract symptoms. Conclusions: Male lower urinary tract symptoms may develop due to abnormal metabolic processes in some pathways. Potential new treatments for lower urinary tract symptoms can be developed by identifying changes in the amino acid profiles.

Lack of Change in the Adaptation Ability of the Bladder for the Urine Production Rate in Aged Men with Nocturia

Introduction: To investigate the association between bladder capacity and the urine production rate in aged men with or without nocturia using a frequency volume chart (FVC). Materials and Methods: One-hundred and thirty-eight men aged 65–80 years were enrolled. After the International Prostate Symptom Score (IPSS) and 3 consecutive days FVC were evaluated, men were divided into 2 groups: Nocturia group, with any total IPSS, and ≥1.5 micturition on average at night; and Control group, with total IPSS < 8 and < 1.5 micturition on average at night. Each parameter was compared between the 2 groups using unpaired t tests. Linear and multiple regression analyses were performed between the urine production rate and volume/voids. Results: Men numbering 45 and 21 were assigned to the Nocturia and Control groups respectively. There were no differences in background factors between the 2 groups. Volume/voids positively correlated with the urine production rate in both groups for day and night. A multivariate regression model also showed the same results. In the Control group, the degree of slope at night was higher than that during the day. However, in the Nocturia group, there were no differences in the degree of slope between day and night. Conclusions: This novel finding has led to a possibility for resolving nocturia.

Development of novel and non‐invasive diagnostic markers for lower urinary tract symptoms using urothelial cells in voided urine

We evaluated the association between lower urinary tract symptoms (LUTS) and the expression of connexin (Cx) and transient receptor potential (TRP) channel on urothelial cells non‐invasively collected from voided urine in humans.

Tadalafil attenuates hypotonicity-induced Ca2+ influx via TRPV2 and TRPV4 in primary rat bladder urothelial cell cultures

To investigate the localization of phosphodiesterase 5 (PDE5) and the molecular mechanism underlying the effect of the PDE5 inhibitor tadalafil in signal transduction in the bladder urothelium.