Figure 5. MCC950 blocks MAC-induced NLRP3 inflammasome activation by human ECs lining human artery xenografts and reduces the enhanced allogeneic memory T cell infiltration in vivo.

(A) Human coronary artery grafts from a single donor were implanted into a set of 4 SCID/bg immunodeficient mice and quiesced for 7 days before pretreatment with NLRP3 inhibitor MCC950 or control DMSO in PBS before PRA or IgG^– sera treatment. After 24 hours, grafts were explanted and retransplanted into a second SCID/bg host with circulating allogeneic PBMCs. Osmotic pumps filled with MCC950 or DMSO in PBS were implanted subcutaneously in the second graft recipient at time of retransplantation. Grafts were recovered after 14 days. The experiment was repeated 3 times with different artery donors. (B) Human ECs lining arterial grafts were identified by Ulex staining and analyzed for cleaved caspase-1 staining by immunofluorescence. Scale bars: 50 μm. (C) Neointimal areas of grafts were assessed between treatment groups following EVG staining. Infiltrating intimal CD3⁺ T cells were identified and quantified following immunohistochemistry staining (n = 3). Scale bars: 50 μm. Data represent mean ± SEM. *P < 0.05, 1-way ANOVA and Tukey’s multiple comparisons test. Results shown are representative of 3 artery grafts from 3 different artery donors.