CB2R inhibits NLRP3 inflammasome activation and augments autophagy in colon from DSS-induced colitis mice.

C57BL/6 mice were treated with vehicle or HU 308 (1 mg/kg, i.p.) once a day from day 0 to day 8 while receiving 3% DSS, the control animals received saline. In another set of experiments, WT and CB2R KO mice received 3% DSS for 8 days, the control mice were given tap water. Colon tissues were isolated from mice at day 8 and the expression of NLRP3, Casp-1 p20/Casp-1 p45 ratio, proIL-1β, LC3-II/LC3-I, Beclin-1 and SQSTM1 were analyzed by Western blot. (A) HU 308 significantly decreased the expression of NLRP3, Casp-1 p20/Casp-1 p45 ratio and proIL-1β. n = 6 per group. *P<0.05 vs. vehicle, **P<0.01 vs. vehicle. (B) In comparison with WT mice, the expression of NLRP3, Casp-1 p20/Casp-1 p45 ratio and proIL-1β were significantly increased in CB2R KO group. n = 6 per group. **P<0.01 vs. WT. (C) HU 308 significantly increased the expression of LC3-II/LC3-I, Beclin-1 and decreased the expression of SQSTM1. n = 6 per group. *P<0.05 vs. vehicle. (D) Compared with WT group, the expression of LC3-II/LC3-I and Beclin-1 was decreased and the expression of SQSTM1 was increased in CB2R KO group. n = 6 per group. *P<0.05 vs. WT.