Candesartan Attenuates Vasculitis in a Mouse Model of Kawasaki Disease Induced by Candida albicans Water-Soluble Fraction.

BACKGROUND: The standard treatment for Kawasaki disease is immunoglobulin therapy, but the high frequency of coronary sequelae in immunoglobulin-refractory cases indicates a need for further improvement in treatment. METHODS: Kawasaki disease-like vasculitis was induced in 5-week-old DBA/2 mice by intraperitoneal administration of 0.5 mg Candida albicans water-soluble fraction (CAWS) daily for 5 days followed by daily administration of candesartan, an angiotensin receptor blocker. The vasculitis suppression effect was confirmed histologically and serologically in mice sacrificed at 28 days after the start of candesartan. RESULTS: The area of inflammatory cell infiltration at the aortic root was 2.4±1.4% in the Control group, 18.1±1.9% in the CAWS group, and 7.1±2.3%, 5.8±1.4%, 7.6±2.4%, and 7.9±5.0% in the CAWS+candesartan 0.125-mg/kg, 0.25-mg/kg, 0.5-mg/kg, and 1.0-mg/kg groups, respectively (p=0.0200, p=0.0122, p=0.0122, and p=0.0200 vs. CAWS, respectively). The low-dose candesartan group also showed significantly reduced inflammatory cell infiltration. A similar trend was confirmed by immunostaining of macrophages and TGFß receptors. Measurement of the inflammatory cytokines IL-1ß, IL-6, and TNF-α confirmed the anti-vasculitis effect of candesartan. CONCLUSIONS: Candesartan inhibited vasculitis even at clinical doses used in children, making it a strong future candidate as an additional treatment for immunoglobulin-refractory Kawasaki disease.

A pathological study on the efficacy of Syk inhibitors in a Candida albicans-induced aortic root vasculitis murine model.

BACKGROUND: The activation of innate immunity may be involved in the development of Candida albicans-induced murine vasculitis, which resembles Kawasaki disease (KD) vasculitis. This study aimed to histologically clarify the time course of the development of vasculitis in this model in detail and to estimate the potential role of spleen tyrosine kinase (Syk) inhibitors in KD vasculitis. METHODS AND RESULTS: DBA/2 male mice were intraperitoneally injected with a vasculitis-inducing substance and treated with a Syk inhibitor (R788 or GS-9973). Systemic vasculitis, especially in the aortic annulus area, was histologically evaluated. Regarding lesions in the aortic annulus area, some mice in the untreated control group already showed initiation of vasculitis 1 day after the final injection of a vasculitis-inducing substance. The vasculitis expanded over time. Inflammation occurred more frequently at the aortic root than at the coronary artery. The distribution of inflammatory cells was limited to the intima, intima plus adventitia, or all layers. In the Syk inhibitor-treated groups, only one mouse had vasculitis at all observation periods. The severity and area of the vasculitis were reduced by both Syk inhibitors. CONCLUSION: Candida albicans-induced murine vasculitis may occur within 1 day after the injection of a vasculitis-inducing substance. Additionally, Syk inhibitors suppress murine vasculitis.

Human Adipose Tissue-Derived Stem Cells Inhibit Coronary Artery Vasculitis in a Mouse Model of Kawasaki Disease.

BACKGROUND: Adipose tissue-derived mesenchymal stem cells (ADSCs) are used for the treatment of various diseases because of their rapid proliferation and high anti-inflammatory and tissue repair properties. Kawasaki disease is a systemic vasculitis with coronary arteritis and aneurysms occurring in pediatric patients. In this study, we examined serologically and pathologically whether the administration of human ADSCs (hADSCs) to a mouse model of Kawasaki disease could suppress vasculitis. METHODS: Candida albicans water-soluble fractions were intraperitoneally injected into DBA/2 mice for 5 consecutive days to generate a mouse model of Kawasaki disease. The model mice were intravenously administered hADSCs or phosphate-buffered saline (PBS). Serum samples collected on days 15 and 29 were used to compare cytokine levels. Mouse hearts dissected on day 29 were subjected to hematoxylin and eosin and immunohistological staining using Galectin-1 (Gal-1), a protein involved in cardiovascular homeostasis, and CD44, a cell-surface marker of hADSCs. RESULTS: Comparison of inflammation-related cytokines showed a significant decrease in IL-1α expression at day 15 (P<0.05) and IL-6 expression at day 29 (P<0.01) in the hADSCs-treated group compared to the PBS group. Evaluation by hematoxylin and eosin staining showed decreased inflammatory cell infiltration and a tendency towards increased Gal-1 expression in the hADSCs group. CD44 expression was not observed in both the groups. The survival curve showed that the hADSCs group had a significantly longer survival time (P<0.05). CONCLUSIONS: The present experimental results indicate that hADSCs have an early anti-inflammatory effect, and that Gal-1 may be involved in preventing inflammation and reducing tissue damage.

Meningitis caused by Chromobacterium haemolyticum suspected to be derived from a canal in Japan: a case report.

BACKGROUND: The genus Chromobacterium, of which 12 species have been recognized, comprises bacteria that reside in tropical and subtropical environments. Of these species, Chromobacterium violaceum and Chromobacterium haemolyticum are known to cause infections in humans. There have been few reports of infections caused by Chromobacterium haemolyticum. CASE PRESENTATION: Chromobacterium haemolyticum was detected in spinal fluid and blood samples isolated from a 73-year-old Japanese male patient who fell into a canal in Kyoto City, Japan and developed bacteremia and meningitis. Although meropenem and vancomycin were administered, this patient died 9 days after admission. Although the infection was misidentified as being caused by Chromobacterium violaceum by conventional identification methods, average nucleotide identity analysis revealed that the causative pathogen was Chromobacterium haemolyticum. The same bacteria were also detected in the canal in which the accident occurred. Phylogenetic analysis of the strain isolated from the patient and the strain isolated from the canal suggested that the two strains were very closely related. CONCLUSIONS: Chromobacterium haemolyticum can be misidentified as Chromobacterium violaceum by conventional identification methods and tends to be more resistant to ß-lactams than Chromobacterium violaceum. Pigment production and ß-hemolysis on blood sheep agar can provide clues for the early identification of Chromobacterium haemolyticum.

Beneficial effects of anti-apolipoprotein A-2 on an animal model for coronary arteritis in Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is usually treated with high-dose intravenous immunoglobulin (IVIg) as severe infectious and other diseases. Due to issues that are associated with immunoglobulin preparation, such as the risk of possible contamination by infectious agents and limited blood banking resources, recombinant immunoglobulins are required. We developed a novel recombinant antibody drug candidate, "VasSF," based on the therapeutic effects it exerted on a mouse spontaneous crescentic glomerulonephritis model (SCG/Kj). Apolipoprotein A-2 (ApoA2) has been identified as one of VasSF's target molecules. METHODS: Here, we tested the potential of anti-apolipoprotein A-2 antibodies (anti-ApoA2) as a new therapeutic drug against KD by examining its effect on a mouse model, in which KD was induced via Candida albicans water-soluble fraction (CAWS). CAWS (2 mg/mouse) was injected intraperitoneally into C57BL/6NCrSlc mice for five consecutive days. The incidence and histological severity of vasculitis in CAWS-induced coronary arteritis in mice administered anti-ApoA2 was examined. The following experimental groups were tested: solvent (only PBS (-) injection); anti-ApoA2 antibodies at dosages of 0.05 mg, 0.1 mg, and 0.5 mg/kg/day; human IgG at 0.1 mg/kg/day. RESULTS: The group treated with anti-ApoA2 0.5 mg/kg/day showed a lower incidence of panvasculitis induced by CAWS, less inflammation of the coronary arteries and aortic roots, and lower levels of serum IL-6, M-CSF, and MIP-1α and 32 cytokines/chemokines compared with those in the solvent group. CONCLUSIONS: The anti-ApoA2 treatment suppressed the development of coronary arteritis in an animal KD model and anti-ApoA2 shows potential as an effective therapeutic candidate for the treatment of KD vasculitis. The use of specific antibodies that display higher vasculitis-suppressing effects, such as anti-ApoA2, may attenuate KD as well as other infectious diseases, with less severe adverse side effects than treatment with IVIg.

Statins Show Anti-Atherosclerotic Effects by Improving Endothelial Cell Function in a Kawasaki Disease-like Vasculitis Mouse Model.

Kawasaki disease (KD) is an acute inflammatory syndrome of unknown etiology that is complicated by cardiovascular sequelae. Chronic inflammation (vasculitis) due to KD might cause vascular cellular senescence and vascular endothelial cell damage, and is a potential cause of atherosclerosis in young adults. This study examined the effect of KD and HMG-CoA inhibitors (statins) on vascular cellular senescence and vascular endothelial cells. Candida albicans water-soluble fraction (CAWS) was administered intraperitoneally to 5-week-old male apolipoprotein E-deficient (ApoE-) mice to induce KD-like vasculitis. The mice were then divided into three groups: control, CAWS, and CAWS+statin groups. Ten weeks after injection, the mice were sacrificed and whole aortic tissue specimens were collected. Endothelial nitric oxide synthase (eNOS) expression in the ascending aortic intima epithelium was evaluated using immunostaining. In addition, eNOS expression and levels of cellular senescence markers were measured in RNA and proteins extracted from whole aortic tissue. KD-like vasculitis impaired vascular endothelial cells that produce eNOS, which maintains vascular homeostasis, and promoted macrophage infiltration into the tissue. Statins also restored vascular endothelial cell function by promoting eNOS expression. Statins may be used to prevent secondary cardiovascular events during the chronic phase of KD.

Kawasaki Disease-like Vasculitis Facilitates Atherosclerosis, and Statin Shows a Significant Antiatherosclerosis and Anti-Inflammatory Effect in a Kawasaki Disease Model Mouse.

Kawasaki disease (KD) is an acute form of systemic vasculitis that may promote atherosclerosis in adulthood. This study examined the relationships between KD, atherosclerosis, and the long-term effects of HMG-CoA inhibitors (statins). Candida albicans water-soluble fraction (CAWS) was injected intraperitoneally into 5-week-old male apolipoprotein-E-deficient (Apo E-/-) mice to create KD-like vasculitis. Mice were divided into 4 groups: the control, CAWS, CAWS+statin, and late-statin groups. They were sacrificed at 6 or 10 weeks after injection. Statin was started after CAWS injection in all groups except the late-statin group, which was administered statin internally 6 weeks after injection. Lipid plaque lesions on the aorta were evaluated with Oil Red O. The aortic root and abdominal aorta were evaluated with hematoxylin and eosin staining and immunostaining. CAWS vasculitis significantly enhanced aortic atherosclerosis and inflammatory cell invasion into the aortic root and abdominal aorta. Statins significantly inhibited atherosclerosis and inflammatory cell invasion, including macrophages. CAWS vasculitis, a KD-like vasculitis, promoted atherosclerosis in Apo E-/- mice. The long-term oral administration of statin significantly suppressed not only atherosclerosis but also inflammatory cell infiltration. Therefore, statin treatment may be used for the secondary prevention of cardiovascular events during the chronic phase of KD.

Sivelestat's effect on Candida albicans water-soluble fraction-induced vasculitis.

BACKGROUND: We investigated the efficacy of sivelestat sodium hydrate (SSH) as a treatment for Kawasaki disease, and its pharmacological action sites, in mice with Candida albicans water-soluble fraction-induced vasculitis. METHODS: Sivelestat sodium hydrate was administered intraperitoneally to Candida albicans water-soluble fraction-induced vasculitis model mice to assess its efficacy in preventing the development of coronary artery lesions based on the degree of inflammatory cell infiltration in the aortic root and coronary arteries (vasculitis score). The pharmacological sites of action were investigated based on changes in neutrophil elastase (NE) and intercellular adhesion molecule 1 (ICAM-1) positive areas, ICAM-1 and tumor necrosis factor-α mRNA expression levels in the upper heart, and the proportion of monocytes in the peripheral blood. RESULTS: The vasculitis score decreased below the lower limit of the 95% confidence interval of untreated mice in 69% of the SSH-treated mice. The NE- and ICAM-1-positive regions, and the mRNA expression of ICAM-1 and tumor necrosis factor-α were lower in the SSH-treated mice than in the untreated mice. The proportion of monocytes in the peripheral blood was higher in the SSH-treated mice than in the untreated mice, whereas monocyte migration to inflammation areas was suppressed in the SSH-treated mice. CONCLUSIONS: Our results showed that SSH might prevent the development of coronary artery lesions and ameliorate disease activity. In addition to its NE-inhibitory effect, SSH sites of action may also include monocytes.

Recombinant Human Soluble Thrombomodulin Suppresses Arteritis in a Mouse Model of Kawasaki Disease.

INTRODUCTION AND OBJECTIVE: Kawasaki disease (KD) is associated with diffuse and systemic vasculitis of unknown aetiology and primarily affects infants and children. Intravenous immunoglobulin (IVIG) treatment reduces the risk of developing coronary aneurysms, but some children have IVIG-resistant KD, which increases their risk of developing coronary artery injury. Here, we investigated the effect of recombinant human soluble thrombomodulin (rTM), which has anticoagulant, anti-inflammatory, and cytoprotective properties on the development of coronary arteritis in a mouse model of vasculitis. METHODS: An animal model of KD-like vasculitis was created by injecting mice with Candida albicans water-soluble fraction (CAWS). This model was used to investigate the mRNA expression of interleukin (IL)-10, tumour necrosis factor alpha (TNF-α), and tissue factor (TF), in addition to histopathology of heart tissues. RESULTS: rTM treatment significantly reduces cardiac vascular endothelium hypertrophy by 34 days after CAWS treatment. In addition, mRNA expression analysis revealed that rTM administration increased cardiac IL-10 expression until day 27, whereas expression of TNF-α was unaffected. Moreover, in the spleen, rTM treatment restores IL-10 and TF expression to normal levels. CONCLUSION: These findings suggest that rTM suppresses CAWS-induced vasculitis by upregulating IL-10. Therefore, rTM may be an effective treatment for KD.

CDCP1 on Dendritic Cells Contributes to the Development of a Model of Kawasaki Disease.

The etiology and pathology of Kawasaki disease (KD) remain elusive. Cub domain-containing protein 1 (CDCP1), a cell-surface protein that confers poor prognosis of patients with certain solid tumors, was recently identified as one of the most significantly upregulated genes in SARS-CoV-2-infected children who developed systemic vasculitis, a hallmark of KD. However, a potential role of CDCP1 in KD has not previously been explored. In this study, we found that CDCP1 knockout (KO) mice exhibited attenuated coronary and aortic vasculitis and decreased serum Candida albicans water-soluble fraction (CAWS)-specific IgM/IgG2a and IL-6 concentrations compared with wild-type mice in an established model of KD induced by CAWS administration. CDCP1 expression was not detectable in cardiomyocytes, cardio fibroblasts, or coronary endothelium, but constitutive expression of CDCP1 was observed on dendritic cells (DCs) and was upregulated by CAWS stimulation. CAWS-induced IL-6 production was significantly reduced in CDCP1 KO DCs, in association with impaired Syk-MAPK signaling pathway activation. These novel findings suggest that CDCP1 might regulate KD development by modulating IL-6 production from DCs via the Syk-MAPK signaling pathway.

Coronary Vasculitis Induced in Mice by Cell Wall Mannoprotein Fractions of Clinically Isolated Candida Species.

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances (CADS) such as the hot water extract of C. albicans and Candida water-soluble fractions (CAWS) induce coronary vasculitis similar to KD in mice. An increasing proportion of deep-seated candidiasis cases are caused by non-albicans Candida and are often resistant to antifungal drugs. We herein investigated whether the mannoprotein fractions (MN fractions) of clinically isolated Candida species induce vasculitis in mice. We prepared MN fractions from 26 strains of Candida species by conventional hot water extraction and compared vasculitis in DBA/2 mice. The results obtained revealed that the induction of vasculitis and resulting heart failure were significantly dependent on the species; namely, death rates on day 200 were as follows: Candida krusei (100%), Candida albicans (84%), Candida dubliniensis (47%), Candida parapsilosis (44%), Candida glabrata (32%), Candida guilliermondii (20%), and Candida tropicalis (20%). Even for C. albicans, some strains did not induce vasculitis. The present results suggest that MN-induced vasculitis is strongly dependent on the species and strains of Candida, and also that the MN fractions of some non-albicans Candida induce similar toxicity to those of C. albicans.

Coronary Vasculitis Induced in Mice by the Cell Wall Mannoprotein of Candida krusei.

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances, such as the hot water extract of C. albicans (CADS) and Candida water-soluble fraction (CAWS), induced coronary vasculitis similar to KD in mice. An increasing proportion of deep-seated candidiasis cases are caused by non-albicans Candida and are often resistant to antifungal drugs. We herein investigated whether the hot water extract of C. krusei, inherently resistant to fluconazole, induces vasculitis in mice. Three strains of C. krusei, NBRC1395, NBRC1162, and NBRC10737, were cultured in natural (Y) and chemically defined (C) media and cell wall mannoprotein (MN) fractions were prepared by autoclaving cells (CKY1395MN, CKC1395MN, CKY1162MN, CKC1162MN, CKY10737MN, and CKC10737MN). All MN fractions reacted strongly with Concanavalin A (Con A) and dectin-2 and induced anaphylactoid shock in ICR mice. MNs induced severe coronary vasculitis in DBA/2 mice, resulting in cardiac hypertrophy. MNs also induced coronary vasculitis in C57Bl/6 mice. These results suggest that the MNs of non-albicans Candida, such as C. krusei, induce similar toxicity to those of C. albicans.

Recognition of alpha-mannan by dectin 2 is essential for onset of Kawasaki disease-like murine vasculitis induced by Candida albicans cell-wall polysaccharide.

Objectives: Using a murine model of systemic Kawasaki disease (KD)-like vasculitis induced by Candida albicans cell-wall-derived mannan · ß-glucan · protein complexes, the objective was to elucidate the relationships of ß-glucan receptor dectin-1 (D1) and α-mannan receptor dectin-2 (D2) to the onset of that vasculitis.Methods: The incidence and histological severity of vasculitis were compared among mice lacking the genes for D1 or D2 (i.e. D1-/- and D2-/-) and wild-type (WT) mice.Results: The incidences of vasculitis in the three animal groups were 100% (18/18) in the WT group, 100% (18/18) in the D1-/- group, and 0% (0/18) in the D2-/- group. In the WT and D1-/- mice, severe inflammatory cell infiltration, consisting mainly of neutrophils and macrophages, was seen in the aortic root and the coronary arteries. On the other hand, in the D2-/- mice, not even mild vascular lesions such as endoarteritis were seen.Conclusion: Recognition of α-mannan by D2 played an important role in the onset of vasculitis in the studied murine model.

Crucial role of NLRP3 inflammasome in a murine model of Kawasaki disease.

Kawasaki disease (KD) is a systemic febrile syndrome during childhood that is characterized by coronary arteritis. The etiopathogenesis of KD remains to be elucidated. NLRP3 inflammasome is a large multiprotein complex that plays a key role in IL-1ß-driven sterile inflammatory diseases. In the present study, we investigated the role of NLRP3 inflammasome in a murine model of KD induced by Candida albicans water-soluble fraction (CAWS) and found that NLRP3 inflammasome is required for the development of CAWS-induced vasculitis. CAWS administration induced IL-1ß production, caspase-1 activation, leukocyte infiltration, and fibrotic changes in the aortic root and coronary arteries, which were significantly inhibited by a deficiency of IL-1ß, NLRP3, and ASC. In vitro experiments showed that among cardiac resident cells, macrophages, but not endothelial cells or fibroblasts, expressed Dectin-2, but did not produce IL-1ß in response to CAWS. In contrast, CAWS induced caspase-1 activation and IL-1ß production in bone marrow-derived dendritic cells (BMDCs), which were inhibited by a specific caspase-1 inhibitor and a deficiency of NLRP3, ASC, and caspase-1. CAWS induced NLRP3 and pro-IL-1ß expression through a Dectin-2/Syk/JNK/NF-κB pathway, and caspase-1 activation and cleavage of pro-IL-1ß through Dectin-2/Syk/JNK-mediated mitochondrial ROS generation, indicating that CAWS induces the priming and activation of NLRP3 inflammasome in BMDCs. These findings provide new insights into the pathogenesis of KD vasculitis, and suggest that NLRP3 inflammasome may be a potential therapeutic target for KD.

Adipose tissue-derived stem cells suppress coronary arteritis of Kawasaki disease in vivo.

BACKGROUND: Kawasaki disease (KD) is a systemic inflammatory disease resulting in an acute febrile syndrome commonly affecting children younger than 5 years. Coronary arteritis in KD is occasionally non-responsive to several treatments. Recently, adipose tissue-derived stem cells (ADSCs) have been shown to have anti-inflammatory, immunosuppressive, and tissue-repair characteristics and are considered a useful treatment for inflammatory disease. The present study aimed to elucidate whether the administration of ADSCs can suppress KD-associated vasculitis in vivo. METHODS: Candida albicans water-soluble fraction is often used to model KD via the induction of severe coronary arteritis. Kawasaki disease model mice were intravenously administered ADSCs and phosphate-buffered saline (PBS). On day 29, the mice were sacrificed and hearts from mice in each group were dissected. This was followed by serum collection. Cardiac tissue sections were subjected to histopathological examination to evaluate the inflammatory area. The levels of pro-inflammatory cytokines in the serum were analyzed at days 15 and 29. The survival rates of both groups were compared. RESULTS: The mean inflammatory area in coronary arteritis was significantly lower in the ADSC group compared to the PBS group (P < 0.01). Furthermore, the levels of pro-inflammatory cytokines, such as IL-1ß, IL-12, IL-17, RANTES, INF-γ, and TNF-α, in the ADSC group were significantly lower than those in the PBS group. Moreover, the ADSC group had a significantly higher survival rate than the PBS group. CONCLUSIONS: These findings highlight that ADSCs have anti-inflammatory and immune regulatory functions that could provide novel cell-based therapeutic strategies for severe KD.

Abrogation of lysophosphatidic acid receptor 1 ameliorates murine vasculitis.

BACKGROUND: Lysophosphatidic acid (LPA), generated by autotaxin (ATX), is a bioactive lipid mediator that binds to the receptors (LPA1-6), and serves as an important mediator in inflammation. Previous studies have demonstrated that LPA-LPA1 cascade contributes to arthritis and skin sclerosis. In this study, we examined the role of LPA signals in murine Candida albicans water-soluble fraction (CAWS)-induced vasculitis. METHODS: ATX and LPA receptor expressions were analyzed by immunohistochemistry and quantitative reverse transcription-polymerase chain reaction. Effects of LPA1 inhibition on CAWS-induced vasculitis were evaluated in LPA1-deficient mice or using an LPA1 antagonist, LA-01. Migration activity was assessed using a chemotaxis chamber. The number of migrated fluorescently labeled neutrophils, which were transferred into the vasculitis mice, was counted in the aortic wall. CXCL1 and IL-8 concentrations were determined by enzyme-linked immunosorbent assay. RESULTS: ATX and LPA1 were highly expressed in the inflamed region of CAWS-induced vasculitis. Severity of the vasculitis in LPA1-deficient mice was suppressed. The LPA1 antagonist, LA-01, also ameliorated the CAWS-induced vasculitis. LPA induced neutrophil migration, which was inhibited by LA-01 in vitro. Infiltration of transferred neutrophils from LPA1-deficient mice into the coronary arteries was suppressed. LA-01 also inhibited the infiltration of wild-type neutrophils. Expression of CXCL1 and IL-8 in human endothelial cells was enhanced by LPA, but was inhibited by LA-01. ATX and LPA1 expression levels were higher in the affected skin region of vasculitis patients than in healthy controls. CONCLUSIONS: These results suggest that LPA-LPA1 signaling contributes to the development of vasculitis via chemoattractant production from endothelial cells followed by neutrophil recruitment. Thus, LPA1 has potential as a novel target for vasculitis therapies.

N-Terminal (1→3)-ß-d-Glucan Recognition Proteins from Insects Recognize the Difference in Ultra-Structures of (1→3)-ß-d-Glucan.

Recognition of (1→3)-ß-d-glucans (BGs) by invertebrate ß-1,3-d-glucan recognition protein (BGRP) plays a significant role in the activation of Toll pathway and prophenoloxidase systems in insect host defense against fungal invasion. To examine the structure diversity of BGRPs for the recognition of physiochemically different BGs, the binding specificity of BGRPs cloned from four different insects to structure different BGs was characterized using ELISA. Recombinant BGRPs expressed as Fc-fusion proteins of human IgG1 bound to the solid phase of BGs. Based on the binding specificities, the BGRPs were categorized into two groups with different ultrastructures and binding characters; one group specifically binds BGs with triple-helical conformation, while the other group recognizes BGs with disordered conformations like single-helical or partially opened triple helix. The BGRPs from the silkworm and the Indian meal moth bound to the BGs with a triple-helical structure, whereas BGRPs from the red flour beetle and yellow mealworm beetle showed no binding to triple-helical BGs, but bound to alkaline-treated BGs that have a partially opened triple-helical conformation. This evidence suggests that the insect BGRPs can distinguish between different conformations of BGs and are equipped for determining the diversity of BG structures.

Dectin-2-induced CCL2 production in tissue-resident macrophages ignites cardiac arteritis.

Environmental triggers, including those from pathogens, are thought to play an important role in triggering autoimmune diseases, such as vasculitis, in genetically susceptible individuals. The mechanism by which activation of the innate immune system contributes to vessel-specific autoimmunity in vasculitis is not known. Systemic administration of Candida albicans water-soluble extract (CAWS) induces vasculitis in the aortic root and coronary arteries of mice that mimics human Kawasaki disease. We found that Dectin-2 signaling in macrophages resident in the aortic root of the heart induced early CCL2 production and the initial recruitment of CCR2+ inflammatory monocytes (iMo) into the aortic root and coronary arteries. iMo differentiated into monocyte-derived dendritic cells (Mo-DC) in the vessel wall and were induced to release IL-1ß in a Dectin-2-Syk-NLRP3 inflammasome dependent pathway. IL-1ß then activated cardiac endothelial cells to express CXCL1 and CCL2 and adhesion molecules that induced neutrophil and further iMo recruitment and accumulation in the aortic root and coronary arteries. Our findings demonstrate that Dectin-2-mediated induction of CCL2 production by macrophages resident in the aortic root and coronary arteries initiates vascular inflammation in a model of Kawasaki disease, suggesting an important role for the innate immune system in initiating vasculitis.

Interleukin-1beta Inhibition Attenuates Vasculitis in a Mouse Model of Kawasaki Disease.

BACKGROUND: Kawasaki disease (KD), a systemic vasculitis, is suspected to be related to abnormalities in innate immunity. Based on the important role of IL-1 signaling in innate immunity, we investigated the effects of an anti-IL-1ß antibody using a Candida albicans water-soluble fraction (CAWS)-induced mouse model of KD. METHODS: CAWS (0.5 mg/mouse) was injected intraperitoneally into 5-week-old DBA/2 mice on five consecutive days. An anti-Murine IL-1ß antibody (01BSUR) was administered at various doses (2.5, 5.0, and 10.0 mg/kg) and time points (2 days before, same day, and 2, 5, 7, and 14 days after CAWS administration). After 4 weeks, vasculitis in the aortic root was investigated histologically. Cytokines including IL-1ß, -6, -10, and TNF-α were also measured. RESULTS: Groups administered 01BSUR at all doses showed a significant reduction in the area of vasculitis. In addition, 01BSUR inhibited vasculitis until 7 days after CAWS administration. In the analysis of various time points, the level of IL-6 was lower in all groups compared to the CAWS only group, but the levels of IL-1ß, TNFα, and IL-10 were lower when 01BSUR was administered before CAWS. On the other hand, TNFα and IL-10 levels were restored when 01BSUR was administered after CAWS, suggesting that 01BSUR may have additional effects beyond blocking IL-1ß signaling. CONCLUSIONS: The anti-IL-1ß antibody significantly attenuated CAWS-induced vasculitis. The mechanism of inhibiting vasculitis is thought to include inhibition of the IL-1ß pathway and additional effects beyond blocking IL-1ß signaling.

Ficolin-1 is a promising therapeutic target for autoimmune diseases.

Previously, we reported that mRNA expression of ficolin-1 (FCN1), a component of the complement lectin pathway, is elevated in peripheral blood mononuclear cells of patients with vasculitis syndrome, and that FCN1-positive cells infiltrate into inflamed regions in patient specimens. In addition, we reported that the serum FCN1 concentration is elevated in patients with Kawasaki disease (KD), a pediatric vasculitis, but dramatically decreases after intravenous immunoglobulin (IVIG) treatment. Furthermore, we showed that FCN1 binds to IgG1 in a pull-down assay. These results suggested that removal of FCN1 may be a therapeutic mechanism of IVIG. In this study, we prepared anti-FCN1 monoclonal antibody (mAb) and examined its therapeutic potential in mice treated with Candida albicans water-soluble fraction (CAWS), which induces KD-like vasculitis in the coronary artery. Indeed, treatment with anti-FCN1 mAb decreased the histological score of vasculitis (P = 0.03). To investigate the role of FCN1, we assessed blood samples of patients with various autoimmune diseases and demonstrated that serum levels of FCN1 were elevated not only in patients with vasculitis, but also in those with rheumatoid arthritis. Additionally, FCN1-targeted treatment of a mouse model of arthritis [collagen antibody-induced arthritis (CAIA)] revealed that administration of anti-FCN1 mAb ameliorated symptoms of arthritis (P < 0.01). These results suggest that FCN1 is involved in the pathogenesis of autoimmune diseases, and that targeting FCN1 represents a promising strategy for treating these diseases.