Nlrp3 Inflammasome Mediates Immune-Stromal Interactions In Vasculitis

Rationale: NLRP3 (NLR family pyrin domain containing 3) activation and IL-1 beta (interleukin-1 beta) production are implicated in Kawasaki disease (KD) pathogenesis; however, a detailed and complete characterization of the molecular networks and cellular subsets involved in the development of cardiovascular lesions is still lacking. Objective: Here, in a murine model of KD vasculitis, we used single-cell RNA sequencing and spatial transcriptomics to determine the cellular landscape of inflamed vascular tissues. Methods and Results: We observe infiltrations of innate and adaptive immune cells in murine KD cardiovascular lesions, associated with increased expression of Nlrp3 and Il1b. Monocytes, macrophages, and dendritic cells were the main sources of IL-1 beta, whereas fibroblasts and vascular smooth muscle cells (VSMCs) expressed high levels of IL-1 receptor. VSMCs type 1 surrounding the inflamed coronary artery undergo a phenotype switch to become VSMCs type 2, which are characterized by gene expression changes associated with decreased contraction and enhanced migration and proliferation. Genetic inhibition of IL-1 beta signaling on VSMCs efficiently attenuated the VSMCs type 2 phenotypic switch and the development of cardiovascular lesions during murine KD vasculitis. In addition, pharmacological inhibition of NLRP3 prevented the development of cardiovascular inflammation. Conclusions: Our studies unravel the cellular diversity involved in IL-1 beta production and signaling in murine KD cardiovascular lesions and provide the rationale for therapeutic strategies targeting NLRP3 to inhibit cardiovascular lesions associated with KD.