Presentation Authors: Kunjie Wang*, Junyu Lai, Jianzhong Ai, Deyi Luo, Tao Jin, Banghua Liao, Liang Zhou, Shijian Feng, Xi Jin, Hong Li, Chengdu, China, People's Republic of
Introduction: Bladder outlet obstruction (BOO) promotes the hyperplasia of bladder detrusor, increases bladder pressure and decreases bladder compliance in clinic. To extensively explore its underlying mechanism, our study aims to investigate the effect of pathological hydrostatic pressure on the bladder smooth muscle cell (BSMC) proliferation and contraction through Î²-adrenoceptor (ADRB) signaling in vitro.
Methods: Human bladder smooth muscle cells (hBSMCs) were treated with the pathological hydrostatic pressure (100 cm H2O), and CCK8, EdU, collagen gel contraction test, RT-PCR and western blot were employed to investigate the effect of ADRB on the proliferation and contraction of BSMCs that were treated with its agonist and/or antagonist.
Results: Firstly, 100 cm H2O hydrostatic pressure significantly upregulated the expression of SMA-Î± of BMSCs at 6 h, however, promoted its proliferation at 24 h. hBSMCs treated with Î²2 and Î²3-adrenoceptor (ADRB2ï¼ŒADRB3) agonists for 6 h under 100 cm H2O could inhibit the SMA-Î± expression when compared to the cells treated with hydrostatic pressure only, nevertheless, hBSMCs treated with ADRB2 agonists for 24 h under hydrostatic pressure could suppress the proliferation of cells when compared to the cells treated with hydrostatic pressure only. the two classical pathways PKA/EPAC of ADRB downstream played respectively role on the contraction and proliferation of hBSMCs under hydrostatic pressure. The PKA and EPAC pathways inhibited the contraction of hBSMCs under hydrostatic pressure via regulating SMAD2 activities, and EPAC showed a predominant role in hBSMC contraction. Furthermore, the proliferation of hBSMCs was mainly determined by EPAC pathway rather than PKA pathway through modulating ERK1/2 activities.
Conclusions: The contraction of hBSMCs under hydrostatic pressure was regulated by ADRB2, ADRB3 via PKA/EPAC-SMAD2 pathway, and the proliferation of hBSMCs under hydrostatic pressure were regulated by ADRB2 via EPAC-ERK1/2 pathways. Compared to ADRB3, ADRB2 play a predominant role under pathological hydrostatic pressure. These findings markedly unraveled the underlying mechanism of ADRB in BOO, and also provided a brand-new view for the efficient treatment of patients with BOO.
Source of Funding: This work was supported by the National Natural Science Foundation of China, grant nos. 81770673, 81470927; from 1.3.5 project for disciplines of excellence, West China Hospital, Sichuan University grant no. ZY2016104.