Cathelicidin (LL-37) causes expression of inflammatory factors in coronary artery endothelial cells of Kawasaki disease by activating TLR4-NF-κB-NLRP3 signaling

[Role and mechanisms of CHI3L1 in coronary artery lesions in a mouse model of Kawasaki disease-like vasculitis]

OBJECTIVES

To explore the role and potential mechanisms of chitinase-3-like protein 1 (CHI3L1) in coronary artery lesions in a mouse model of Kawasaki disease (KD)-like vasculitis.

METHODS

Four-week-old male SPF-grade C57BL/6 mice were randomly divided into a control group and a model group, with 10 mice in each group. The model group mice were intraperitoneally injected with 0.5 mL of lactobacillus casei cell wall extract (LCWE) to establish a mouse model of KD-like vasculitis, while the control group mice were injected with an equal volume of normal saline. The general conditions of the mice were observed on the 3rd, 7th, and 14th day after injection. Changes in coronary artery tissue pathology were observed using hematoxylin-eosin staining. The level of CHI3L1 in mouse serum was measured by enzyme-linked immunosorbent assay. Immunofluorescence staining was used to detect the expression and localization of CHI3L1, von Willebrand factor (vWF), and α-smooth muscle actin (α-SMA) in coronary artery tissue. Western blot analysis was used to detect the expression of CHI3L1, vWF, vascular endothelial cadherin (VE cadherin), Caspase-3, B cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), nuclear factor κB (NF-κB), and phosphorylated NF-κB (p-NF-κB) in coronary artery tissue.

RESULTS

The serum level of CHI3L1 in the model group was significantly higher than that in the control group (P<0.05). Compared to the control group, the expression of CHI3L1 in the coronary artery tissue was higher, while the expression of vWF was lower in the model group. The relative expression levels of CHI3L1, Bax, Caspase-3, NF-κB, and p-NF-κB were significantly higher in the model group than in the control group (P<0.05). The relative expression levels of vWF, VE cadherin, and Bcl-2 were lower in the model group than in the control group (P<0.05).

CONCLUSIONS

In the LCWE-induced mouse model of KD-like vasculitis, the expression levels of CHI3L1 in serum and coronary arteries increase, and it may play a role in coronary artery lesions through endothelial cell apoptosis mediated by inflammatory reactions.

Neutrophils in Inflammatory Diseases: Unraveling the Impact of Their Derived Molecules and Heterogeneity

Inflammatory diseases involve numerous disorders and medical conditions defined by an insufficient level of self-tolerance. These diseases evolve over the course of a multi-step process through which environmental variables play a crucial role in the emergence of aberrant innate and adaptive immunological responses. According to experimental data accumulated over the past decade, neutrophils play a significant role as effector cells in innate immunity. However, neutrophils are also involved in the progression of numerous diseases through participation in the onset and maintenance of immune-mediated dysregulation by releasing neutrophil-derived molecules and forming neutrophil extracellular traps, ultimately causing destruction of tissues. Additionally, neutrophils have a wide variety of functional heterogeneity with adverse effects on inflammatory diseases. However, the complicated role of neutrophil biology and its heterogeneity in inflammatory diseases remains unclear. Moreover, neutrophils are considered an intriguing target of interventional therapies due to their multifaceted role in a number of diseases. Several approaches have been developed to therapeutically target neutrophils, involving strategies to improve neutrophil function, with various compounds and inhibitors currently undergoing clinical trials, although challenges and contradictions in the field persist. This review outlines the current literature on roles of neutrophils, neutrophil-derived molecules, and neutrophil heterogeneity in the pathogenesis of autoimmune and inflammatory diseases with potential future therapeutic strategies.