Cannabinoid receptor 2 activation decreases severity of cyclophosphamide‐induced cystitis via regulating autophagy. Issue 1 (14th November 2019)

• Record Type: Journal Article
• Authors: Liu, Qinggang; Wu, Zonglong; Liu, Yaxiao; Chen, Lipeng; Zhao, Hongda; Guo, Hongda; Zhu, Kejia; Wang, Wenfu; Chen, Shouzhen; Zhou, Nan; Li, Yan; Shi, Benkang
• Is Part Of: Neurourology and urodynamics. Volume 39:Issue 1(2020:Jan.)
• Page Start: 158
• Page End: 169
• Publication Date: 2019-11-14
• Subjects: AMPK -- autophagy -- cannabinoid receptor 2 -- cystitis -- interstitial -- mice -- mTOR -- urinary bladder; Urinary organs -- Periodicals; Urodynamics -- Periodicals; Urology -- Periodicals; 616.6
• DOI: 10.1002/nau.24205
• Languages: English
• ISSNs: 0733-2467

Abstract

Abstract: Purpose: Cannabinoids have been shown to exert analgesic and anti‐inflammatory effects, and the effects of cannabinoids are mediated primarily by cannabinoid receptors 1 and 2 (CB1 and CB2). The objective of this study was to determine efficacy and mechanism of CB2 activation on cyclophosphamide (CYP)‐induced cystitis in vivo. Methods: Cystitis was induced by intraperitoneal (IP) injection of CYP in female C57BL/6J mice. Mice were pretreated with CB2 agonist JWH‐133 (1 mg/kg, intraperitoneally), CB2 antagonist AM‐630 (1 mg/kg, intraperitoneally) or autophagy inhibitor 3‐methyladenine (3‐MA) (50 mM, intraperitoneally) before IP injection of CYP. Peripheral nociception and spontaneous voiding were investigated in these mice. Bladders were collected, weighed, and processed for real‐time polymerase chain reaction, immunoblotting analysis, histological and immunohistochemical analysis. Results: Twenty‐four hours after IP injection of CYP, the bladder of CYP‐treated mice showed histological evidence of inflammation. The expression of CB2 in bladder was significantly increased in CYP‐treated mice. Mechanical sensitivity was significantly increased in CYP‐treated mice and CB2 agonist JWH‐133 attenuated this effect ( P < .05). The number of urine spots was significantly increased after CYP treatment and it was decreased in JWH‐133 treated mice ( P < .05). Activating CB2 with JWH‐133 significantly alleviated bladder tissue inflammatory responses and oxidative stress induced by CYP. Activation of CB2 by JWH‐133 increased the expression of LC3‐II/LC3‐I ratio, and decreased the expression of SQSTM1/p62 in the bladder of cystitis mice, whereas AM‐630 induced inverse effects. Further study indicated that JWH‐133 could promote autophagy and blocking autophagy by 3‐MA dismissed the effort of CB2 in alleviating bladder tissue inflammatory responses and oxidative stress injury. Furthermore, treatment with 3‐MA decreased the expression of p‐AMPK and induced the phosphorylation of mTOR in the presence of JWH‐133 stimulation in cystitis model. Conclusions: Activation of CB2 decreased severity of CYP‐induced cystitis and ameliorated bladder inflammation. CB2 activation is protective in cystitis through the activation of autophagy and AMPK‐mTOR pathway may be involved in the initiation of autophagy.