Spatiotemporal regulation of acute wound healing by the NLRP3 inflammasome: dual roles in macrophage-fibroblast chemotaxis and phenotype during wound repair

The spatiotemporal regulation of inflammatory dynamics is critical for successful wound healing. However, the precise mechanistic role of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in orchestrating these processes remains incompletely characterized. This study aimed to delineate the specific mechanisms by which NLRP3 governs cellular and molecular events during wound healing.

Multi-omics sequencing data were utilized to profile NLRP3 inflammasome activation dynamics in murine and human acute wound models. Nlrp3−/− mice were generated using CRISPR-Cas9 technology. In vitro and in vivo functional assays were performed to assess NLRP3-dependent regulation of macrophage and fibroblast recruitment, polarization, and phenotype modulation.

NLRP3 is predominantly expressed in macrophages and neutrophils during the inflammatory phase of wound healing. Global deletion of Nlrp3 reduces IL-1β, the main downstream effector, attenuates CCL/CXCL chemokine signaling, decreases both inflammatory and pro-reparative cell infiltration, and disrupts the phenotypic switching of macrophages and fibroblasts, collectively delaying wound closure. However, the resulting low-inflammatory microenvironment in Nlrp3−/− mice may upregulate Wnt and Notch signaling early in the repair phase, curbing fibrosis and promoting appendage regeneration. Partial IL-1β blockade in WT mice recapitulates the NLRP3-null phenotype, whereas IL-1β reconstitution in knockout mice accelerates healing but increases fibrosis. Moreover, the NLRP3 protein also modulates fibroblast phenotype independently of inflammasome activation via a ROS-dependent mechanism.

NLRP3 exerts dual-phase regulatory roles in wound healing: (ⅰ) during inflammation, it drives chemokine-mediated macrophage/fibroblast recruitment and M1 polarization while suppressing fibroblast-mediated repair via IL-1β signaling; (ⅱ) later, NLRP3 deficiency enhances Wnt/Notch signaling, promoting structural restoration despite transiently delayed healing. Moreover, fibroblasts with high NLRP3 expression engage an inflammasome-independent NLRP3/ROS axis that augments activation of TGF-β/Smad signaling. These findings position NLRP3 as a potential therapeutic target for modulating phase-specific inflammatory and regenerative responses.