The activation of CaN/NFAT signaling pathway in macrophages aggravated Lactobacillus casei cell wall extract-induced Kawasaki disease vasculitis.

OBJECTIVES: By using GWAS(genome-wide association studies) and linkage disequilibrium analysis to investigate the susceptibility genes of KD(Kawasaki disease), previous studies have identified that the CaN(calcineurin)-NFAT(the nuclear factor of activated T cell) signal pathway were significantly associated with susceptibility to KD. However, little is known about the molecular basis of the CaN/NFAT pathway involved in KD. Therefore, in our study we investigate the role of Ca2+/CaN/NFAT signaling pathway in macrophages in vitro and in vivo on coronary artery lesions induced by LCWE (Lactobacillus casei cell wall extract). METHODS AND RESULTS: We observed that LCWE could increase the expression of NFAT1 and NFAT2 in macrophages in vitro, and also enhance the transcriptional activity of NFAT by promoting the nucleus translocation. Similarly, in LCWE-induced mice model, the expression of NFAT1 and NFAT2 and associated proinflammatory factors were increased significantly. In addition, by knocking down or overexpressing NFAT1 or NFAT2 in macrophages, the results indicated that NFAT signaling pathway mediated LCWE-induced immune responses in macrophages and regulated the synthesis of IL(interleukin)-6, IL-1ß and TNF(tumor necrosis factor)-α in LCWE-induced macrophage activation. As well, we found that this process could be suppressed by CaN inhibitor CsA(cyclosporinA). CONCLUSIONS: Therefore, the CaN/NFAT signaling pathway mediated LCWE-induced immune responses in macrophages, and also participated in the LCWE-induced CALs(coronary artery lesions). And also the inhibitory effect of CsA in LCWE-induced cell model towards a strategy to modulate the CaN/NFAT pathway during the acute course of KD might be helpful in alleviate KD-induced CALs.

Inhibition of endogenous hydrogen sulfide production improves viral elimination in CVB3-infected myocardium in mice.

BACKGROUND: To find whether administration of hydrogen sulfide has interaction with coxsackie virus B3 (CVB3) replication and spread. METHODS: Six-week-old inbred male Balb/c mice were injected intraperitoneally with CVB3. Mice were randomized to four groups (n = 10 for each group): group N (sham infection + vehicle), group C (virus + vehicle), group P (virus + DL-proparglygylcine (PAG)), and group S (virus + sodium hydrogen sulfide (NaHS)). PAG and NaHS were administered intraperitoneally daily and mice were killed on day 4 after viral inoculation. Serum specimens were obtained to assay tumor necrosis factor-α (TNFα) level, and heart specimens were harvested for histological examination, 50% tissue culture infection dose (TCID50) assay, reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: The ratio of heart-weight to body-weight and inflammatory scores showed no significant difference between infected groups. The circulatory and local concentrations of TNFα, nitric oxide synthase 2 messenger RNA, and protein were higher in group P, and were lower in group S compared to those in group C. Mice treated with PAG and NaHS had significantly lower and higher viral stocks than those inoculated with CVB3 only, respectively. CONCLUSION: Inhibition of endogenous hydrogen sulfide production contributed to viral clearance in acute viremia of CVB3-induced myocarditis.

KCa3.1 Inhibition of Macrophages Suppresses Inflammatory Response Leading to Endothelial Damage in a Cell Model of Kawasaki Disease.

PURPOSE: Macrophages-mediated inflammation is linked with endothelial damage of Kawasaki disease (KD). KCa3.1, a calcium-activated potassium channel, modulates inflammation of macrophages. However, little is known about the role of KCa3.1 in inflammation by macrophages involved in KD. Hence, this study is aimed to explore the potential role of KCa3.1 in regulating inflammatory response by macrophages and subsequent vascular injury in an in vitro model of KD. METHODS: RAW264.7 cells were stimulated with Lactobacillus casei cell wall extract (LCWE) with or without TRAM-34 or PDTC or AG490. Subsequently, mouse coronary artery endothelial cells (MCAECs) were incubated with RAW264.7 cells-conditioned medium to mimic local inflammatory lesions in KD. CCKi8 assay was used to evaluate cell viability. The mRNA levels of inflammatory mediators were detected by qRT-PCR. Expressions of KCa3.1, MCAECs injury-associated molecules, proteins involved in signal pathways of nuclear factor-κB (NF-κB), signal transducers and activators of transcription (STAT) 3 and p38 were evaluated by Western blot. RESULTS: Our study showed that LCWE increased KCa3.1 protein level in RAW264.7 macrophages and KCa3.1 inhibition by TRAM-34 notably suppressed the expression of pro-inflammatory molecules in LCWE-treated macrophages via blocking the activation of NF-κB and STAT3 pathways. Besides, the inflammation and damage of MCAECs were attenuated in the TRAM-34-treated group compared with the KD model group. This vascular protective role was dependent on the down-regulation of NF-κB and STAT3 signal pathways, which was confirmed by using inhibitors of NF-κB and STAT3. CONCLUSION: This study demonstrates that KCa3.1 blockade of macrophages suppresses inflammatory reaction leading to mouse coronary artery endothelial cell injury in a cell model of KD by hampering the activation of NF-κB and STAT3 signaling pathway. These findings imply that KCa3.1 may be a potential therapeutic target for KD.

Altered Monocyte Subsets in Kawasaki Disease Revealed by Single-cell RNA-Sequencing.

BACKGROUND: Kawasaki disease (KD) is characterized by a disorder of immune response, and its etiology remains unknown. Monocyte is an important member of the body's innate immune system; however its role in KD is still elusive due to its ambiguous heterogeneity and complex functions. We aim to comprehensively delineate monocyte heterogeneity in healthy and KD infants and to reveal the underlying mechanism for KD. METHODS: Peripheral monocytes were enriched from peripheral blood samples of two healthy infants and two KD infants. scRNA-seq was performed to acquire the transcriptomic atlas of monocytes. Bio-information analysis was utilized to identify monocyte subsets and explore their functions and differentiation states. SELL+CD14+CD16- monocytes were validated using flow cytometry. RESULTS: Three monocyte subsets were identified in healthy infants, including CD14+CD16- monocytes, CD14+CD16+ monocytes, and CD14LowCD16+ monocytes. Cell trajectory analysis revealed that the three monocyte subsets represent a linear differentiation, and possess different biological functions. Furthermore, SELL+CD14+CD16- monocytes, which were poorly differentiated and relating to neutrophil activation, were found to be expanded in KD. CONCLUSION: Our findings provide a valuable resource for deciphering the monocyte heterogeneity in healthy infants and uncover the altered monocyte subsets in KD patients, suggesting potential biomarkers for KD diagnosis and treatment.

The Network of Pro-Inflammatory Factors CD147, DcR3, and IL33 in the Development of Kawasaki Disease.

INTRODUCTION: Kawasaki disease (KD) is an acute febrile systemic vasculitis, but the etiology remains unknown. We studied serum levels of CD147, DcR3, and IL33 in different stages of KD to explore the value of CD147, DcR3, and IL33 in the pathophysiology of KD. METHODS: We measured serum levels of CD147, DcR3, and IL33 by enzyme-linked immunosorbent assay (ELISA) at different stages with 71 KD patients and 66 healthy control children. We apply for network tools GeneMANIA and Cytoscape APP to analyze the functions of these pro-inflammatory factors at the gene and protein level. RESULTS: Serum levels of CD147, DcR3, and IL33 were significantly increased in KD patients before IVIG treatment. Serum levels of CD147, DcR3, and IL33 gradually decreased over time after the treatment of IVIG. Eight cases were IVIG non-responders, while nine KD patients got CALs, but they did not overlap. And there were no statistical differences between group IVIG responders and IVIG non-responders or between groups without CALs and with CALs. We explored the functions of CD147, DcR3, and IL33 from GeneMANIA and Cytoscape APP and found these third pro-inflammatory factors were coexpressed, physical interactions, genetic interactions with other KD-related factors. CONCLUSION: CD147, DcR3, and IL33 are involved in the pathophysiology of KD, which provides novel evidence for diagnosing and treating KD with their inhibitors.

Crucial transcripts predict response to initial immunoglobulin treatment in acute Kawasaki disease.

Although intravenous immunoglobulin (IVIG) can effectively treat Kawasaki disease (KD), 10-20% of KD patients show no beneficial clinical response. Developing reliable criteria to discriminate non-responders is important for early planning of appropriate regimens. To predict the non-responders before IVIG treatment, gene expression dataset of 110 responders and 61 non-responders was obtained from Gene Expression Omnibus. After weighted gene co-expression network analysis, we found that modules positively correlated with the non-responders were mainly associated with myeloid cell activation. Transcripts up-regulated in the non-responders, IL1R2, GK, HK3, C5orf32, CXCL16, NAMPT and EMILIN2, were proven to play key roles via interaction with other transcripts in co-expression network. The crucial transcripts may affect the clinical response to IVIG treatment in acute KD. And these transcripts may serve as biomarkers and therapeutic targets for precise diagnosis and treatment of the non-responders.

The elevated serum levels of calcineurin and nuclear factor of activated T-cells 1 in children with Kawasaki disease.

BACKGROUND: The calcineurin and nuclear factor of activated T-cells (CaN-NFAT) signaling pathway had been found to be associated with Kawasaki disease (KD) susceptibility and coronary artery aneurysm formation as a contributor. To evaluate serum calcineurin (CaN) and nuclear factor of activated T-cells 1(NFAT1) levels in patients with Kawasaki disease (KD). METHODS: Serum levels of CaN and NFAT1 were measured by enzyme-linked immunosorbent assay method in 66 healthy children and 74 KD patients at acute, afebrile and subacute stage. RESULTS: The serum levels of CaN and NFAT1 increased significantly in the acute stage, and decreased progressively in the afebrile and subacute stage, along with the reduction of C-reactive protein, white blood cells and neutrophil counts. And in the acute stage, the afebrile stage and the subacute stage, the expression of CaN and NFAT1 was upregulated significantly in KD patients compared to that in the healthy control. After the IVIG treatment, the serum levels of CaN and NFAT1 declined significantly in IVIG responders. However, the CaN and NTAT1 levels in the IVIG non-responders declined slowly. And in the afebrile stage, the NFAT1 levels were lower in KD patients with coronary artery lesions (CALs) (268.82 ± 11.96 ng/ml) than those without CALs (285.84 ± 25.13 ng/ml). However, the serum levels of CaN in KD patients with CALs had no significant difference with those in KD patients without CALs. CONCLUSIONS: The specific regulation of CaN and NFAT1 serum levels in the course of KD was suggested that both of them were related in the development of KD.

The role of Ca2+/NFAT in Dysfunction and Inflammation of Human Coronary Endothelial Cells induced by Sera from patients with Kawasaki disease.

Ca2+/nuclear factor of activated T-cells (Ca2+/NFAT) signaling pathway may play a crucial role in the pathogenesis of Kawasaki disease (KD). We investigated the poorly understood Ca2+/NFAT regulation of coronary artery endothelial cells and consequent dysfunction in KD pathogenesis. Human coronary artery endothelial cells (HCAECs) stimulated with sera from patients with KD, compared with sera from healthy children, exhibited significant increases in proliferation and angiogenesis, higher levels of NFATc1 and NFATc3 and some inflammatory molecules, and increased nuclear translocation of NFATc1 and NFATc3. HCAECs stimulated with sera from patients with KD treated with cyclosporine A (CsA) showed decreased proliferation, angiogenesis, NFATc1 and inflammatory molecules levels as compared with results for untreated HCAECs. In conclusion, our data reveal that KD sera activate the Ca2+/NFAT in HCAECs, leading to dysfunction and inflammation of endothelial cells. CsA has cytoprotective effects by ameliorating endothelial cell homeostasis via Ca2+/NFAT.