Angiotensin II induces macrophage M1 polarization by activating connexin 43

: Objective To observe the effect of connexin 43 (Cx43) on angiotensin II (AngII)-induced M1 polarization of RAW264.7 macrophages. Methods RAW264.7 macrophages were divided into control group, AngII group and Gap26 pretreatment group. The AngII group was given AngII (10-6 mol/L) for 12 hours. The pretreatment group was treated with Gap26 (10-5 mol/L) for 30 minutes first and then AngII (10-6 mol/L) for 12 hours. Western blot analysis was used to determine the protein expression of Cx43, M1 markers CD86 and inducible nitric oxide synthase (iNOS); the mRNA expression of CD86, iNOS and tumor necrosis factor-α (TNF-α) were detected by real-time quantitative PCR; the expression of CD86 and iNOS on macrophages in each group were observed by confocal microscopy. Results Compared with the control group, the expression of CD86, iNOS and TNF-α significantly increased in AngII group. The levels of CD86, iNOS and TNF-α in Gap26 pretreatment group were significantly lower than those in AngII group, however, higher than the control group. Moreover, the expression of CD86 was mainly on the cell membrane, and iNOS was expressed in the whole cell. Conclusion AngII could induce M1 polarization of macrophage, and Cx43 specific blocker Gap26 could inhibit AngII-induced M1 polarization.