Abstract
The aim of the study was to investigate the role and mechanisms of action of nuclear factor-κB (NF-κB)-mediated caspase-4 activation in the induction of inflammatory cytokines during Kawasaki disease (KD) and coronary artery endothelial cell injury. Peripheral blood mononuclear cells (PBMCs) were isolated from KD patients and healthy controls and cultured. Double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was applied to detect tumor necrosis factor (TNF)-α levels in activated PBMC-conditioned culture media. To establish a culture model for human coronary artery endothelial cells (HCAECs), we employed KD patient-origin PBMC culture-conditioned media to induce HCAEC transformation and detected the nuclear activation of NF-κB p65 and intracellular caspase-4 protein concentrations using western blot analysis. We also investigated the nuclear transfer of NF-κB p65 using immunofluorescence, as well as HCAEC interleukin (IL)-6 and IL-1β secretion using ELISA. Finally, we investigated HCAEC apoptosis using using Annexin V/PI double staining. After PBMCs were stimulated in vitro, TNF-α secretion was significantly higher in the KD group versus controls (P<0.01). HCAEC cells treated with supernatant conditioned by cells from KD patients showed a significant elevation of NF-κB p65 and caspase-4 protein expression versus HCAEC cells treated with supernatant conditioned by control cells (P<0.01). Similarly, IL-6 and IL-1β secretion, as well as apoptotic rate, were significantly elevated (P<0.01). SN50, an NF-κB inhibitor, significantly attenuated caspase-4 expression, secretion of IL-6, IL-1β, and TNF-α, as well as HCAEC apoptosis in cells treated with KD patient PBMC-conditioned media. NF-κB can induce the generation of various inflammatory factors including IL-6 and IL-1β, mediate the expression of caspase-4 in HCAEC cells, and affect apoptosis and injury of HCAEC cells. Therefore, the expression of caspase-4, mediated by NF-κB signal pathway, plays a critical role in KD.