Abstract Body: Kawasaki disease is a systemic disorder of enigmatic origin, postulated to stem from an aberrant immune response possibly triggered by infectious agents. This condition prominently risks developing vasculitis, particularly in the coronary arteries, which may lead to aneurysm formation, a grave complication. To shed light on the mechanisms underpinning Kawasaki vasculitis, a thorough investigation was conducted on patients presented at emergency departments. Whole RNA sequencing was utilized to analyze samples from individuals with general infectious diseases, acting as controls, and those diagnosed with Kawasaki disease, forming the experimental group. This approach identified a set of 13 microRNAs (miRNAs) that exhibited increased levels in patients with Kawasaki disease. Following initial findings, the Lactobacillus casei cell wall extract (LCWE)-induced vasculitis animal model, a recognized analog for human Kawasaki vasculitis, was employed to validate the relevance of these miRNAs. Among them, miR-10b-5p was pinpointed as a critical regulator; its inhibition via antagomirs markedly mitigated inflammation near the aortic valve in the LCWE-induced model. To uncover the direct downstream targets of miR-10b-5p relevant to Kawasaki vasculitis, single-cell RNA sequencing was performed. This revealed alterations in human coronary artery endothelial cells (HCAECs) upon miR-10b-5p treatment. Specifically, a subpopulation of HCAECs, initially characterized by proliferation, shifted towards a pro-inflammatory cluster upon miR-10b-5p exposure. This transformation was marked by a decrease in the expression of the proliferation marker, Ki-67 (MKI67), in the pro-inflammatory cluster. Further whole RNA sequencing on HCAECs treated with miR-10b-5p confirmed a significant downregulation of MKI67. Subsequent experiments with siRNA-mediated knockdown of MKI67 resulted in an increase in C-X-C Motif Chemokine Ligand 8 (CXCL8) expression, a pivotal cytokine in inflammation. These findings suggest a novel signaling pathway involving miR-10b-5p, MKI67, and CXCL8, potentially serving as a therapeutic target for Kawasaki vasculitis management in future interventions.