β-Adrenoceptors regulate matrix metalloproteinase expression in human urothelial cells under hydrostatic pressure

β-Adrenoceptors regulate urothelial inflammation and zonula occludens in the bladder outlet obstruction model

BACKGROUND

The purpose of this study was to evaluate the effects of β-adrenoceptors (ADRBs) on the urothelial inflammation and zonula occludens (ZO) in a rat PBOO model and in an in vitro model.

METHODS

The PBOO model was established by ligating the bladder neck of rats. Twenty rats were divided into 4 groups: sham operation, PBOO + normal saline, PBOO + ADRB2 agonist, PBOO + ADRB3 agonist. PBOO rats were with treated with ADRBs agonists for 3 weeks. Human urothelial cells (HUCs) were subjected to ADRBs agonist treatment or hydrostatic pressure in an in vitro model.

RESULTS

In the PBOO group, there was a significant increase in the expression of MCP-1, IL-6 and RANTES compared to the sham group. By contrast, there was a post-PBOO decline in the expression of ZO-1 and ZO-2 in the urothelium. ADRB2 or ADRB3 agonists exhibited downregulated inflammatory cytokine expression and increased ZO expression in the PBOO model. The regulation of inflammation and ZO by ADRB2 and ADRB3 agonists in an in vitro model was found consistent with that in the PBOO model. Moreover, RhoA and ROCK inhibitors suppressed the expression of hydrostatic pressure-induced inflammatory cytokines. Additionally, RhoA agonist reversed the inhibitory effect of ADRBs agonists on the inflammatory secretion from HUCs.

CONCLUSIONS

ADRB2 and ADRB3 agonists increased ZO protein expression in HUCs in a rat PBOO model and in an in vitro model. Furthermore, ADRB2 and ADRB3 agonists inhibited the secretion of inflammatory cytokines from HUCs by regulating the RhoA/ROCK signaling pathways.

β3 Relaxant Effect in Human Bladder Involves Cystathionine γ-Lyase-Derived Urothelial Hydrogen Sulfide

It is now well established that the urothelium does not act as a passive barrier but contributes to bladder homeostasis by releasing several signaling molecules in response to physiological and chemical stimuli. Here, we investigated the potential contribution of the hydrogen sulfide (H2S) pathway in regulating human urothelium function in β3 adrenoceptor-mediated relaxation. The relaxant effect of BRL 37344 (0.1–300 µM), a selective β3 adrenoceptor agonist, was evaluated in isolated human bladder strips in the presence or absence of the urothelium. The relaxant effect of BRL 37344 was significantly reduced by urothelium removal. The inhibition of cystathionine-γ-lyase (CSE), but not cystathionine-β-synthase (CBS), significantly reduced the BRL 37344 relaxing effect to the same extent as that given by urothelium removal, suggesting a role for CSE-derived H2S. β3 adrenoceptor stimulation in the human urothelium or in T24 urothelial cells markedly increased H2S and cAMP levels that were reverted by a blockade of CSE and β3 adrenoceptor antagonism. These findings demonstrate a key role for urothelium CSE-derived H2S in the β3 effect on the human bladder through the modulation of cAMP levels. Therefore, the study establishes the relevance of urothelial β3 adrenoceptors in the regulation of bladder tone, supporting the use of β3 agonists in patients affected by an overactive bladder.