Exaggerated Kawasaki disease-associated vasculitis in C-C Motif Chemokine Receptor 5 (CCR5) deficient mice is driven by Granulocyte Colony Stimulating Factor (G-CSF) overproduction and neutrophil formation and infiltration
Authors: Costa Rafael , Alves Juliano , Bruder-Nascimento Ariane , Ayupe Marina , Dev Gagan , Awata Wanessa , Singh Shubhnita 
Published: May 2024

Kawasaki disease (KD) is a rare but serious illness that primarily affects children. It is characterized by inflammation of the blood vessels throughout the body, including the coronary arteries (CA). Polymorphisms in CCR5 influence KD susceptibility and cardiovascular outcome, but the mechanisms are enigmatic yet. Thus, we aimed to explore the mechanisms by which polymorphisms in CCR5 aggravate the vascular injury in KD by using the Candida albicans water soluble (CAWS) fraction model. Male (6-10-weeks-old) CCR5 deficient mice (CCR5−/−) and their counterpart (CCR5+/+) were used. Cardiac single-cell transcriptomics (scRNAseq) analysis of both control and KD mice revealed an inflammatory landscape characterized by an abundance of macrophages, monocytes, and neutrophils. Additionally, our scRNAseq data indicated that CCR5 expression is predominantly observed in macrophages and monocytes in KD mice, whereas its ligands, CCL3 and CCL4, are primarily expressed in neutrophils. Our CellChat analysis uncovered robust intercommunication between neutrophils and macrophages and monocytes. This interaction involves the production of CCL3 and CCL4 by neutrophils, which act on CCR5 receptors in macrophages and monocytes. To validate this scRNAseq data, we analyzed the vasculitis levels in CA and immune cells content in CCR5+/+ and CCR5−/− mice with KD via histology and flow cytometry. CCR5−/− mice with KD exhibited aggravated vasculitis, increased neutrophil accumulation [(% in relation to 10^6 leukocytes) CCR5+/+: 2.5±1.7 n=4 vs. CCR5+/+ KD: 16.1±3.2 n=4], and CCR5−/− KD: 30.2±7.4 n=4), alongside cardiac senescence (3-fold rise in p21 expression) and a 2-fold increase in Caspase-3, indicating increased cell death compared to CCR5+/+ with KD. Mechanistically, our plasma proteome profile cytokine assay revealed that KD increases circulating IL-6 and circulating neutrophil, interestingly CCR5−/− mice with KD showed further circulating IL-6 and neutrophil along with G-CSF, which plays a critical role in stimulating the production and release of granulocytes, particularly neutrophils, from the bone marrow into the bloodstream. Thus, deficiency in CCR5 triggers a worse vasculitis in KD by regulating an over production of neutrophil by bone marrow via G-CSF, which in turn will lead to an exaggerated IL-6 production, further accumulation in CA, and aggravated cardiac damage. FAPESP (2022/06639-2), NHLBI-R00 (R00HL14013903), AHA (CDA857268 and 23DIVSUP1069230), Vascular Medicine Institute, the Hemophilia Center of Western Pennsylvania Vitalant, and Children's Hospital of Pittsburgh of the UPMC Health System. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.