Phosphodiesterase-5 inhibition inhibits epithelial ATP release and restores detrusor contractility in rats with type 2 diabetes via an increase in bladder blood flow

Kabuto, T.; Inamura, S.; Kobayashi, H.; Zha, X.; Nagase, K.; Taga, M.; Seki, M.; Tanaka, N.; Okumura, Y.; Yokoyama, O.; Terada, N.

doi:10.1101/2024.03.26.586851

bioRxiv · 10.1101/2024.03.26.586851

Phosphodiesterase-5 inhibition inhibits epithelial ATP release and restores detrusor contractility in rats with type 2 diabetes via an increase in bladder blood flow

Kabuto, T.·Inamura, S.·Kobayashi, H.·Zha, X.·Nagase, K.·Taga, M.·Seki, M.·Tanaka, N.·Okumura, Y.·Yokoyama, O.·Terada, N.

View original source ↗Export metadata ↓

Abstract

PurposeThe bladder dysfunction associated with type 2 diabetes mellitus (T2DM) involves urine storage and voiding disorders. We evaluated the pathologic conditions of bladder wall in a rat model of T2DM and evaluated the effects of the phosphodiesterase-5 (PDE-5) inhibitor tadalafil (TA). Materials and MethodsMale Otsuka Long-Evans Tokushima Fatty (OLETF) rats and Long-Evans Tokushima Otsuka (LETO) rats comprised T2DM and control groups. TA was orally administered for 12 weeks. The bladder blood flow and ATP released from the bladder epithelium were measured using laser speckle imaging and an organ bath bladder distention test. The expression levels of markers of hypoxia, pro-inflammatory cytokines, and growth factors in the bladder wall were measured by real-time PCR and ELISA. The contractions of bladder strips in response to KCl and carbachol were monitored in OLETF rats. ResultsThe bladder blood flow was impaired and there was greater ATP release and vesicular nucleotide transporter (VNUT) expression in the OLETF rats than in the LETO rats, but these effects were suppressed by TA administration. Furthermore, the high expression of HIF-1, 8-OHdG, IL-6, TNF-, IGF-1, and bFGF in the OLETF rats was reduced by TA administration. In the OLETF rats, the contractile responses of bladder strips to KCl and carbachol were impaired, but were restored by TA administration. ConclusionsThe impairment of bladder blood flow in rats with T2DM is associated with greater ATP release and the upregulation of VNUT, markers of hypoxia, proinflammatory cytokines, and growth factors in the bladder epithelium. PDE5 inhibition has the potential to prevent the storage and voiding dysfunction associated with T2DM.

Explore related subjects

pharmacology and toxicology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Kabuto, T., Inamura, S., Kobayashi, H., Zha, X., Nagase, K., Taga, M., Seki, M., Tanaka, N., Okumura, Y., Yokoyama, O., Terada, N.. 2024-03-29. Phosphodiesterase-5 inhibition inhibits epithelial ATP release and restores detrusor contractility in rats with type 2 diabetes via an increase in bladder blood flow. https://doi.org/10.1101/2024.03.26.586851

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Context and exposure history shape insecticide sensitivity in Drosophila melanogaster

Current insecticide toxicology still lacks an integrated understanding of how lethal and sublethal exposure shape organismal performance across biologically and environmentally relevant contexts. In particular, insecticide susceptibility may vary with physiological state, environmental conditions, and recent exposure history, factors that are only partially captured by standardized toxicity assessments. Here, using Drosophila melanogaster, we systematically compared responses to three insecticides with distinct modes of action - acetamiprid, chlorantraniliprole, and deltamethrin - across developmental stages, sexes, adult ages, and ambient temperatures. Insecticide sensitivity varied substantially across these conditions, with temperature modulating toxicity in a compound-dependent manner. Notably, deltamethrin caused substantial lethality at concentrations more than 10,000-fold below approved field application rates. Beyond these context-dependent differences in acute toxicity, sublethal pre-exposure to each insecticide rapidly reduced lethality during a subsequent challenge with the same compound, with increased tolerance already detectable after 24 h. Importantly, these exposure conditions that enhanced insecticide tolerance were associated with reduced resistance to environmental challenges, including heat and nutrient starvation, revealing a potential trade-off in organismal stress resilience. Acetamiprid exposure further altered reproductive performance in a concentration-dependent manner, with higher exposure reducing egg production while increasing developmental success among the resulting offspring, such that the number of offspring reaching adulthood remained largely unchanged. Together, these findings demonstrate that insecticide susceptibility is highly context dependent and can be rapidly modified by recent exposure history. We identify short-term, compound-specific, and potentially costly tolerance as an underappreciated consequence of insecticide exposure and highlight the importance of incorporating biological context, environmental conditions, and sublethal exposure history into pesticide risk assessment.

pharmacology and toxicology↗

bioRxiv2026

Aquaporin-9 and aquaporin-10 but not aquaporin-3 confer susceptibility to dimethylarsinic acid genotoxicity in human cells

Human metabolism converts inorganic arsenic to the pentavalent methylated species MMA(V) and DMA(V), the forms most people excrete, and the forms long read as the end of a detoxification pathway. Whether a transporter sets how much of these metabolites reaches the genome has not been tested in a mammalian cell. We expressed human AQP3, AQP7, AQP9 or AQP10 in HEK293T and MRC5-SV40 cells and measured gamma-H2AX by flow cytometry across dose series of As(V), MMA(V) and DMA(V), pairing every aquaporin with a GFP-Tubulin control and an untransfected mock acquired in the same replicate. As(V) was inactive in HEK293T cells and only weakly active in MRC5-SV40 cells to 20 micromolar, and both methylated species damaged DNA only in the millimolar range, DMA(V) being the more potent of the two in both cell lines. Against that weak baseline, AQP9 and AQP10 raised DMA(V)-induced gamma-H2AX in HEK293T cells by roughly 17 percentage points over the matched control, more than doubling the damage the same exposure produced in control cells, whereas AQP3 and AQP7 changed it not at all. AQP9 alone remained active with MMA(V). The ranking held in MRC5-SV40 fibroblasts at one-sixth the size, and within single wells the damage rose with the amount of AQP9 a cell carried while the control was flat. Aquaglyceroporins therefore discriminate among arsenic species, and AQP9 and AQP10 turn a weakly genotoxic metabolite into a substantially more genotoxic one.

pharmacology and toxicology↗

bioRxiv2026

Quantitative Systems Pharmacology Model for Trop-2 Targeting Antibody-Drug Conjugate in Triple-Negative Breast Cancer

TROP2-targeted antibody-drug conjugates (ADCs) have demonstrated promising clinical activity in triple-negative breast cancer (TNBC) as monotherapies; however, therapeutic benefit varies among patients. Combination strategies pairing TROP2-targeted ADCs with immune checkpoint inhibitors are also being investigated. Elucidating the mechanistic drivers of ADC monotherapy variability and enabling the rational development of combination regimens require computational frameworks that integrate ADC pharmacology with tumor-immune interactions. A quantitative systems pharmacology (QSP) model is presented that incorporates an ADC module into our established immuno-oncology model for TNBC. The module captures ADC and payload pharmacokinetics and pharmacodynamics. TNBC heterogeneity is represented by two tumor cell clones with high and low TROP2 expression, informed by prior characterizations, and differential sensitivity to the ADC payload is incorporated as an intrinsic property of each clone. Although generalizable, the model was applied to the TROP2-targeted ADC sacituzumab govitecan (SG, TRODELVY). A virtual patient cohort was generated using Latin hypercube sampling and calibrated against objective response rate (ORR) data from SG Phase I/II TNBC basket trial. The model predicted an ORR of 33.2% consistent with ASCENT study (NCT02574455). Simulations suggest TROP2-mediated delivery contributes modestly to SG efficacy with tumor exposure driven largely by systemically released SN-38 payload being sufficient to induce cytotoxicity. Tumor heterogeneity emerged as a key determinant of response with ORR increasing as the fraction of payload-sensitive clones increased. Overall, this QSP framework for TROP2-targeted ADCs accounts for TNBC heterogeneity and is extendable to other ADCs and targets enabling interrogation of ADC mechanisms of action in conjunction with tumor-immune interactions.

pharmacology and toxicology↗