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Zinn's zonule is a fragile and thin tissue, and little is known about its pathogenesis. The aim of this study was to develop an experimental setup for a comprehensive analysis of Zinn's zonule. Rats were divided into two groups: a control group (n = 4) and an alkali injury group (n = 4). Seven days after injury, the eyes were enucleated, the anterior eye was dissected and embedded in gelatin, and macroscopic observations were made. The gelatin specimens were then embedded in paraffin and observed in detail by low-vacuum scanning electron microscopy, immunofluorescence, and quantitative reverse transcription polymerase chain reaction (RT-qPCR). The results show qualitative changes in Zinn's zonules in both macroscopic and microscopic observations. In addition, macrophage infiltration and increased matrix metalloproteinase 2 (MMP2) expression were observed in the injured group, consistent with the RT-qPCR results. The experimental system in this study allowed us to capture the morphological and molecular biological changes of Zinn's zonule and to gain insight into its pathogenesis. In conclusion, this study presents a new experimental setup for the comprehensive analysis of the rat Zinn's zonule. The results suggest that this system can be used in the future to study and analyze a variety of paraffin-embedded tissues and specimens.

DOI： 10.3390/ijms24076254

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BACKGROUND: Immune checkpoint inhibitors (ICIs) have provided significant benefits in cancer treatment, but they could develop immune-related adverse events (irAE). ICI-associated renal adverse effects are rare and tubulointerstitial nephritis (TIN) is the most common in the renal irAE. However, only a few case reports of renal vasculitis associated with ICI have been reported. In addition, the characteristics of infiltrating inflammatory cells of ICI-associated TIN and renal vasculitis have been uncertain. CASE PRESENTATION: A 65-year-old man received immune checkpoint inhibitors (ICIs), anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) and anti-PD-1 (programmed cell death 1) antibodies for aggravated metastatic malignant melanoma. About 1 week after the second administration of nivolumab and ipilimumab, acute kidney injury developed. A renal biopsy was performed that showed TIN and non-necrotizing granulomatous vasculitis in interlobular arteries. Massive CD3+ T cells and CD163+ macrophages infiltrated both tubulointerstitium and interlobular arteries. Many infiltrating cells tested positive for Ki-67 and PD-1 ligand (PD-L1), but negative for PD-1. In CD3+ T cells, CD8+ T cells were predominantly infiltrated, and these cells were positive for Granzyme B (GrB) and cytotoxic granule TIA-1, but negative for CD25, indicating antigen-independent activated CD8+ T cells. Infiltration of CD4+ T cells was noted without obvious CD4+ CD25+ regulatory T (Treg) cells. His renal dysfunction recovered within 2 months of treatment with prednisolone in addition to discontinuation of nivolumab and ipilimumab. CONCLUSIONS: We herein reported a case of ICI-related TIN and renal granulomatous vasculitis with infiltration of massive antigen-independent activated CD8+ T cells and CD163+ macrophages, and none or few CD4+ CD25+ Treg cells. These infiltrating cells might be a characteristic of the development of renal irAE.

DOI： 10.1186/s12882-023-03091-8

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FROUNT is an intracellular protein that promotes pseudopodia formation by binding to the chemokine receptors CCR2 and CCR5 on macrophages. Recently, disulfiram (DSF), a drug treatment for alcoholism, was found to have FROUNT inhibitory activity. In this study, we investigated the effect of DSF eye drops in a rat corneal alkali burn model. After alkali burn, 0.5% DSF eye drops (DSF group) and vehicle eye drops (Vehicle group) were administered twice daily. Immunohistochemical observations and real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses were performed at 6 h and 1, 4, and 7 days after alkali burn. Results showed a significant decrease in macrophage accumulation in the cornea in the DSF group, but no difference in neutrophils. RT-PCR showed decreased expression of macrophage-associated cytokines in the DSF group. Corneal scarring and neovascularization were also suppressed in the DSF group. Low-vacuum scanning electron microscopy imaging showed that macrophage length was significantly shorter in the DSF group, reflecting the reduced extension of pseudopodia. These results suggest that DSF inhibited macrophage infiltration by suppressing macrophage pseudopodia formation.

DOI： 10.3390/ijms24010735

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Activated monocytes/macrophages promote glomerular injury, including crescent formation, in anti-glomerular basement membrane (GBM) glomerulonephritis. Disulfiram, an alcohol-aversion drug, inhibits monocyte/macrophage migration by inhibiting FROUNT, a cytosolic protein that enhances chemokine receptor signaling. Our study found that disulfiram at a human equivalent dose successfully blocked albuminuria and crescent formation with podocyte loss, and later stage kidney fibrotic lesions, in a rat model of anti-GBM glomerulonephritis. A disulfiram derivative, DSF-41, with more potent FROUNT inhibition activity, inhibited glomerulonephritis at a lower dose than disulfiram. Disulfiram markedly reduced the number of monocytes or macrophages at the early stage of glomerulonephritis and that of CD3+ and CD8+ lymphocytes at the established stage. Impaired pseudopodia formation was observed in the glomerular monocytes/macrophages of the disulfiram group; consistent with the in vitro observation that disulfiram blocked chemokine-dependent pseudopodia formation and chemotaxis of bone marrow-derived monocytes/macrophages. Furthermore, disulfiram suppressed macrophage activation as revealed by reduced expression of inflammatory cytokines and chemokines (TNF-α, CCL2, and CXCL9) and reduced CD86 and MHC class II expressions in monocytes/macrophages during glomerulonephritis. The dramatic reduction in monocyte/macrophage number might have resulted from disulfiram suppression of both the chemotactic response of monocytes/macrophages and their subsequent activation to produce cytokines and chemokines, which further recruit monocytes. Additionally, FROUNT was expressed in CD68+ monocytes/macrophages infiltrating the crescentic glomeruli in human anti-GBM glomerulonephritis. Thus, disulfiram can be a highly effective and safe drug for the treatment of glomerulonephritis by blocking the chemotactic responses of monocytes/macrophages and their activation status in the glomerulus.

DOI： 10.1016/j.kint.2022.07.031

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BACKGROUND: The intrauterine adverse environment during nephrogenesis reduces the nephron number, probably associates with impaired ureteric bud (UB) branching. METHODS: The kidneys in C57/BL6 mice were irradiated with a single dose of 10 gray (10 Gy) as adverse environment on postnatal day 3 (irradiated PND3 kidneys) after UB branching ceased. The renal functions and pathological findings of irradiated PND3 kidneys were compared with those of non-irradiated control and 10 Gy irradiation on PND14 (irradiated PND14 kidney) from 1 to 18 months. RESULTS: The number and density of glomeruli in irradiated PND3 kidneys were reduced by 1 month with renal dysfunction at 6 months. The morphologically incomplete glomeruli with insufficient capillaries were involuted by 1 month in the superficial cortex. Reduced tubular numbers and developmental disability with shortening renal tubules occurred in irradiated PND3 kidneys with impaired urine concentration at 6 months. Hypertrophy of glomeruli developed, and occasional sclerotic glomeruli appeared in the juxtamedullary cortex with hypertension and albuminuria at 12 to 18 months. CONCLUSIONS: The reduced number of nephrons with shortening renal tubules occurred with impaired renal functions in a postnatal adverse environment after cessation of UB branching, and glomerular hypertrophy with occasional glomerulosclerosis developed accompanied with hypertension and albuminuria in the adulthood. IMPACT: The reduced number of nephrons with shortening renal tubules occurred with impaired renal functions in a postnatal adverse environment after cessation of ureteric bud branching. The reduced number of glomeruli were associated with not only the impaired formation of glomeruli but also involution of morphologically small incomplete glomeruli after an adverse environment. The insufficiently developed nephrons were characterized by the shortening renal tubules with impaired urine concentration. In addition, glomerular hypertrophy and occasional glomerulosclerosis developed with hypertension and albuminuria in adulthood. The present study can help to understand the risk of alternations of premature nephrons in preterm neonates.

DOI： 10.1038/s41390-022-02332-0

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Low-vacuum scanning electron microscopy (LV-SEM) is a powerful tool that allows to observe light microscopic specimens with periodic acid-silver methenamine (PAM) staining at a higher magnification, simply by removing the coverslip. However, it is not suitable for observation of immunohistochemistry (IHC) using 3,3'-diaminobenzidine (DAB) due to insufficient backscattered electron image. Traditional heavy metal enhancement techniques for DAB in IHC, (1) osmium tetroxide and iron, (2) cobalt, (3) methenamine silver (Ag), (4) gold chloride (Gold), and (5) both Ag and Gold (Ag + Gold), were examined by LV-SEM. Tissue specimens from Thy1.1 glomerulonephritis rat kidney stained with α-smooth muscle actin and visualized with DAB were enhanced by each of these enhancement methods. We found, in light microscopic and LV-SEM, that the enhancement with Ag, Gold, or Ag + Gold had better intensity and contrast than others. At a higher magnification, Ag + Gold enhancement showed high intensity and low background, although only Ag or Gold enhancement had nonspecific background. Even after observation by LV-SEM, the quality of specimens was maintained after remounting the coverslip. It was also confirmed that Ag + Gold enhancement could be useful for IHC using clinical human renal biopsy. These findings indicate that Ag + Gold provided an adequate enhancement in IHC for both LM and LV SEM observation.

DOI： 10.1369/00221554221102996

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Disulfiram is an FDA approved drug for the treatment of alcoholism. The drug acts by inhibiting aldehyde dehydrogenase, an enzyme essential to alcohol metabolism. However, a recent study has demonstrated that disulfiram also potently inhibits the cytoplasmic protein FROUNT, a common regulator of chemokine receptor CCR2 and CCR5 signaling. Several studies have reported that chemokine receptors are associated with the regulation of emotional behaviors in rodents, such as anxiety. Therefore, this study was performed to clarify the effect of disulfiram on emotional behavior in rodents. The anxiolytic-like effects of disulfiram were investigated using an elevated plus-maze (EPM) test, a typical screening model for anxiolytics. Disulfiram (40 or 80 mg/kg) significantly increased the amount of time spent in the open arms of the maze and the number of open arm entries without affecting the total open arms entries. Similar results were obtained in mice treated with a selective FROUNT inhibitor, disulfiram-41 (10 mg/kg). These disulfiram-associated behavioral changes were similar to those observed following treatment with the benzodiazepine anxiolytic diazepam (1.5 mg/kg). Moreover, disulfiram (40 mg/kg) significantly and completely attenuated increased extracellular glutamate levels in the prelimbic-prefrontal cortex (PL-PFC) during stress exposure on the elevated open-platform. However, no effect in the EPM test was seen following administration of the selective aldehyde dehydrogenase inhibitor cyanamide (40 mg/kg). In contrast to diazepam, disulfiram caused no sedation effects in the open-field, coordination disorder on a rotarod, or amnesia in a Y-maze. This is the first report suggesting that disulfiram produces anxiolytic-like effects in rodents. We found that the presynaptic inhibitory effects on glutaminergic neurons in the PL-PFC may be involved in its underlying mechanism. Disulfiram could therefore be an effective and novel anxiolytic drug that does not produce benzodiazepine-related adverse effects, such as amnesia, coordination disorder, or sedation, as found with diazepam. We propose that the inhibitory activity of disulfiram against FROUNT function provides an effective therapeutic option in anxiety.

DOI： 10.3389/fphar.2022.826783

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Uterine leiomyosarcoma (ULMS) with osteoclast-like giant cells (OLGCs) has been reported as a rare phenomenon in ULMS, and its clinico-pathological features and tumorigenesis remain unclear. We recently reported high expression of receptor activator of nuclear factor κB ligand (RANKL) in ULMS with OLGCs. As osteoblasts produce RANKL, in this study, we analyzed the expression of Runt-related transcription factor 2 (RUNX2), a critical transcription factor for osteoblasts, and osteoclast-related proteins in three cases of ULMS with OLGCs as well as five conventional ULMSs and nine leiomyomas. Immunohistochemistry and real-time reverse transcription quantitative polymerase chain reaction analyses showed high expression of RUNX2 and RANKL in ULMS with OLGCs. In these cases, macrophages expressed receptor activator of nuclear factor κB (RANK), and OLGCs expressed osteoclast-related proteins (nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), and cathepsin K). Accumulation sites of cathepsin K-positive OLGCs showed hemorrhagic appearance and degraded type IV collagen. We reviewed reported cases of ULMS with OLGCs, including ours, and found that they presented an aggressive course even at stage I. Furthermore, metastatic lesions showed similar histological features to those of OLGC association in ULMS. Here, we show that tumor cells in ULMS with OLGCs highly express RUNX2 and RANKL and that osteoclastic differentiation of macrophages occurs in the tumor tissue.

DOI： 10.1007/s00428-020-02996-1

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Suppression of protein aggregation is a subject of growing importance in the treatment of protein aggregation diseases, an urgent worldwide human health problem, and the production of therapeutic proteins, such as antibody drugs. We previously reported a method to identify compounds that suppress aggregation, based on screening using multiple terminal deletion mutants. We now present a method to determine the aggregation contact sites of proteins, using such solubilizing compounds, to design monodispersed mutants. We applied this strategy to the chemokine receptor-binding domain (CRBD) of FROUNT, which binds to the membrane-proximal C-terminal intracellular region of CCR2. Initially, the backbone NMR signals were assigned to a certain extent by available methods, and the putative locations of five α-helices were identified. Based on NMR chemical shift perturbations upon varying the protein concentrations, the first and third helices were found to contain the aggregation contact sites. The two helices are amphiphilic, and based on an NMR titration with 1,6-hexanediol, a CRBD solubilizing compound, the contact sites were identified as the hydrophobic patches located on the hydrophilic sides of the two helices. Subsequently, we designed multiple mutants targeting amino acid residues on the contact sites. Based on their NMR spectra, a doubly mutated CRBD (L538E/P612S) was selected from the designed mutants, and its monodispersed nature was confirmed by other biophysical methods. We then assessed the CCR2-binding activities of the mutants. Our method is useful for the protein structural analyses, the treatment of protein aggregation diseases, and the improvement of therapeutic proteins.

DOI： 10.1021/acs.biochem.0c00414

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FROUNT is a cytoplasmic protein that interacts with the membrane-proximal C-terminal regions (Pro-Cs) of the CCR2 and CCR5 chemokine receptors. The interactions between FROUNT and the chemokine receptors play an important role in the migration of inflammatory immune cells. Therefore, FROUNT is a potential drug target for inflammatory diseases. However, the structural basis of the interactions between FROUNT and the chemokine receptors remains to be elucidated. We previously identified the C-terminal region (residues 532-656) of FROUNT as the structural domain responsible for the Pro-C binding, referred to as the chemokine receptor-binding domain (CRBD), and then constructed its mutant, bearing L538E/P612S mutations, with improved NMR spectral quality, referred to as CRBD_LEPS. We now report the main-chain and side-chain 1H, 13C, and 15N resonance assignments of CRBD_LEPS. The NMR signals of CRBD_LEPS were well dispersed and their intensities were uniform on the 1H-15N HSQC spectrum, and thus almost all of the main-chain and side-chain resonances were assigned. This assignment information provides the foundation for NMR studies of the three-dimensional structure of CRBD_LEPS in solution and its interactions with chemokine receptors.

DOI： 10.1007/s12104-018-9819-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Blackwell Publishing Ltd  

The control of protein solubility is a subject of broad interest. Although several solvent screening methods are available to search for compounds that enhance protein solubilization, their performance is influenced by the intrinsic solubility of the tested protein. We now present a method for screening solubilizing compounds, using an array of N- or C-terminal deletion mutants of the protein. A key behind this approach is that such terminal deletions of the protein affect its aggregation propensity. The solubilization activities of trial solvents are individually assessed, based on the number of solubilized mutants. The solubilizing compounds are then identified from the screened solvents. In this study, the C-terminal chemokine receptor-binding region of the cytoplasmic protein, FROUNT (FNT-C), which mediates intracellular signals leading to leukocyte migration, was subjected to the multicomponent screening. In total, 192 solution conditions were tested, using eight terminal deletion mutants of FNT-C. We identified five solvent conditions that solubilized four or five mutants of FNT-C, and the compounds in the screened solvents were then, respectively, assessed in terms of their solubilization ability. The best compound for solubilizing FNT-C was 1,6-hexanediol. Indeed, 1,6-hexanediol bound to FNT-C and suppressed its precipitation, as showed by NMR and dynamic light scattering analyses.

DOI： 10.1111/gtc.12554

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HUMANA PRESS INC  

FROUNT is a cytoplasmic protein that binds to the membrane-proximal C-terminal regions (Pro-Cs) of chemokine receptors, CCR2 and CCR5. The FROUNT-chemokine receptor interactions play a pivotal role in the migration of inflammatory immune cells, indicating the potential of FROUNT as a drug target for inflammatory diseases. To provide the foundation for drug development, structural information of the Pro-C binding region of FROUNT is desired. Here, we defined the novel structural domain (FNT-CB), which mediates the interaction with the chemokine receptors. A recombinant GST-tag-fused FNT-CB protein expression system was constructed. The protein was purified by affinity chromatography and then subjected to in-gel protease digestion of the GST-tag. The released FNT-CB was further purified by anion-exchange and size-exclusion chromatography. Purified FNT-CB adopts a helical structure, as indicated by CD. NMR line-broadening indicated that weak aggregation occurred at sub-millimolar concentrations, but the line-broadening was mitigated by using a deuterated sample in concert with transverse relaxation-optimized spectroscopy. The specific binding of FNT-CB to CCR2 Pro-C was confirmed by the fluorescence-based assay. The improved NMR spectral quality and the retained functional activity of FNT-CB support the feasibility of further structural and functional studies targeted at the anti-inflammatory drug development.

DOI： 10.1007/s12033-017-0002-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC CANCER RESEARCH  

Depletion of CD4(+) cells in tumor-bearing mice has strong antitumor effects. However, the mechanisms underlying these effects and the therapeutic benefits of CD4(+) cell depletion relative to other immunotherapies have not been fully evaluated. Here, we investigated the antitumor effects of an anti-CD4-depleting mAb as a monotherapy or in combination with immune checkpoint mAbs. In B16F10, Colon 26, or Lewis lung carcinoma subcutaneous tumor models, administration of the anti-CD4 mAb alone had strong antitumor effects that were superior to those elicited by CD25(+) Treg depletion or other immune checkpoint mAbs, and which were completely reversed by CD8(+) cell depletion. CD4(+) cell depletion led to the proliferation of tumor-specific CD8(+) T cells in the draining lymph node and increased infiltration of PD-1(+)CD8(-) T cells into the tumor, with a shift toward type I immunity within the tumor. Combination treatment with the anti-CD4 mAb and immune checkpoint mAbs, particularly anti-PD-1 or anti-PD-L1 mAbs, synergistically suppressed tumor growth and greatly prolonged survival. To our knowledge, this work represents the first report of robust synergy between anti-CD4 and anti-PD-1 or anti-PD-L1 mAb therapies. (C)2015 AACR.

DOI： 10.1158/2326-6066.CIR-14-0190

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Blackwell Publishing Ltd  

The membrane-proximal C-terminal region (Pro-C) is important for the regulation of G-protein-coupled receptors (GPCRs), but the binding of the Pro-C region to a cytosolic regulator has not been structurally analyzed. The chemokine receptor CCR2 is a member of the GPCR superfamily, and the Pro-C region of CCR2 binds to the cytosolic regulator FROUNT. Studying the interaction between CCR2 Pro-C and FROUNT at an atomic level provides a basis for understanding the signal transduction mechanism via GPCRs. NOE-based NMR experiments showed that, when bound to FROUNT, CCR2 Pro-C adopted a helical conformation, as well as when embedded in dodecylphosphocholine micelles. A comparison of two types of cross-saturation-based NMR experiments, applied to a three-component mixture of Pro-C, FROUNT and micelles or a two-component mixture of Pro-C and micelles, revealed that the hydrophobic binding surface on Pro-C for FROUNT mostly overlapped with the binding site for micelles, suggesting competitive binding of Pro-C between FROUNT and micelles. Leu316 was important for both FROUNT and micelle binding. Phe319 was newly identified to be crucial for FROUNT binding, by NMR and mutational analyses. The association and dissociation rates of CCR2 Pro-C for lipid bilayer biomembranes were faster than those for FROUNT. We previously reported that FROUNT binding to CCR2 is detectable even in unstimulated cells and increases in response to chemokine stimulation. Taken together, these results support a model of CCR2 equilibrium: chemokine binding changes the conformational equilibrium of CCR2 toward the active state, and Pro-C switches its binding partner from the membrane to FROUNT.

DOI： 10.1111/febs.13096

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PORTLAND PRESS LTD  

Chemokine receptors mediate the migration of leucocytes during inflammation. The cytoplasmic protein FROUNT binds to chemokine receptors CCR2 [chemokine (C-C motif) receptor 2] and CCR5, and amplifies chemotactic signals in leucocytes. Although the interaction between FROUNT and chemokine receptors is important for accurate chemotaxis, the interaction mechanism has not been elucidated. In the present study we identified a 16-amino-acid sequence responsible for high-affinity binding of FROUNT at the membrane-proximal C-terminal intracellular region of CCR2 (CCR2 Pro-C) by yeast two-hybrid analysis. Synthesized peptides corresponding to the CCR2 Pro-C sequence directly interacted with FROUNT in vitro. CCR2 Pro-C was predicted to form an amphipathic helix structure. Residues on the hydrophobic side are completely conserved among FROUNT-binding receptors, suggesting that the hydrophobic side is the responsible element for FROUNT binding. The L316T mutation to the hydrophobic side of the predicted helix decreased the affinity for FROUNT. Co-immunoprecipitation assays revealed that the CCR2 L316T mutation diminished the interaction between FROUNT and full-length CCR2 in cells. Furthermore, this mutation impaired the ability of the receptor to mediate chemotaxis. These findings provide the first description of the functional binding element in helix 8 of CCR2 for the cytosolic regulator FROUNT that mediates chemotactic signalling.

DOI： 10.1042/BJ20130827

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Objective. Vasculitis is characterized by leukocyte infiltration in the vessel walls, with destructive damage to mural structures. Retinoids are compounds that bind to retinoic acid receptors and exert biologic activities similar to those of vitamin A, including modulatory effects on cell proliferation and differentiation. This study was undertaken to examine the therapeutic effects of a synthetic retinoid, Am80, in a murine model of vasculitis induced by Candida albicans water-soluble fraction (CAWS).
Methods. Vasculitis was induced in BALB/c mice by intraperitoneal injection of CAWS. Neutrophils were depleted by injection of antineutrophil antibody-positive serum. Am80 was administered orally once daily. Vasculitis was evaluated histologically. Migration of labeled adoptively transferred cells was quantified. Chemotaxis was assessed by cell mobility analysis. Production of reactive oxygen species (ROS) and phosphorylation of MAPKs were measured by flow cytometry. Concentrations of elastase were measured by enzyme-linked immunosorbent assay.
Results. Administration of CAWS induced vasculitis in the coronary arteries and aortic root, with abundant neutrophil infiltration. Depletion of neutrophils reduced CAWS-induced vasculitis. Treatment with Am80 led to a significant attenuation of the vasculitis score and inhibition of the migration of transferred neutrophils into the site of vasculitis. In vitro, Am80 suppressed fMLP-induced chemotaxis of human peripheral blood neutrophils. ROS production and elastase release by stimulated neutrophils were reduced by AM80 treatment, and Am80 also inhibited phosphorylation of ERK-1/2 and p38 in neutrophils stimulated with fMLP plus lipopolysaccharide.
Conclusion. Am80 significantly suppressed CAWS-induced vasculitis. This effect was presumably exerted via inhibition of neutrophil migration and activation.

DOI： 10.1002/art.37784

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Chemokine receptors play pivotal roles for immune cell recruitment to inflammation sites, in response to chemokine gradients (chemotaxis). The mechanisms of chemokine signaling, especially the initiation of the intracellular signaling cascade, are not well understood. We previously identified a cytoplasmic protein FROUNT, which binds to the C-terminal regions of CCR2 and CCR5 to mediate chemokine signaling. Although large amounts of purified protein are required for detailed biochemical studies and drug screening, no method to produce recombinant FROUNT has been reported. In this study, we developed a method for the production of recombinant human FROUNT. Human FROUNT was successfully expressed in Escherichia coli, as a soluble protein fused to the folding chaperone Trigger Factor, with a cold shock expression system. The purified FROUNT protein displayed CCR2 binding ability without any additional components, as demonstrated by SPR measurements. A gel filtration analysis suggested that FROUNT exists in a homo-oligomeric state. This high-yield method is cost-effective for human FROUNT production. It should be a powerful tool for further biochemical and structural studies to elucidate GPCR regulation and chemokine signaling, and also will contribute to drug development. (c) 2010 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.pep.2010.12.012

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Language：English   Publisher：The Japanese Society of Inflammation and Regeneration  

Nearly two decades have passed since our discovery of the prototypic chemokines, a neutrophil chemotactic factor interleukin 8 (IL 8, CXCL8) and monocyte chemotactic factor MCAF/MCP-1 (CCL2) at the National Cancer Institute, USA. The characterization of chemokines has revealed the molecular mechanisms underlying specific leukocyte subset infiltration into inflammatory tissues, previously a long-standing enigma in inflammation research. In this review we briefly recount the chronology of chemokine research, then overview chemokine receptor signal transduction systems, chemokines in inflammation and immunity, chemokines in HIV infection and cancer, and the current status of therapeutic approaches targeting chemokines and their receptors.

DOI： 10.2492/inflammregen.31.11

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC IMMUNOLOGISTS  

FROUNT is a known CCR2-binding protein that facilitates monocyte/macrophage infiltration. Here we report that FROUNT also hinds to the C-terminal region of CCR5 and enhances CCR5-mediated cellular chemotaxis. We show that FROUNT overexpression enhances the directionality of chemotaxis, while FROUNT suppression results in impaired responsiveness. Furthermore, we found an increase in consolidated pseudopodium formation in FROUNT-overexpressing cells (FNT cells) on uniform stimulation with CCL4 (MIP1-beta), a specific ligand of CCR5. In most FNT cells, one to two pseudopodia directed toward higher chemokine concentration were found, whereas most FNT-suppressed cells had multiple pseudopodia. The data indicate that FROUNT is involved in sensing and amplifying a shallow extracellular chemokine gradient that leads to a limited number of accurate pseudopodia directed toward the chemokine concentration. In addition to its separate roles in CCR2- and CCR5-mediated chemotaxis, FROUNT, as a common regulator of these receptors, possibly plays a crucial role in the recruitment of immune cells expressing these receptors. The Journal of Immunology, 2009, 183: 6387-6394.

DOI： 10.4049/jimmunol.0803469

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Antiviral cell-mediated immunity is initiated by the dendritic cell ( DC) network in lymph nodes (LNs). Plasmacytoid DCs (pDCs) are known to migrate to inflamed LNs and produce interferon (IFN)-alpha, but their other roles in antiviral T cell immunity are unclear. We report that LN-recruited pDCs are activated to create local immune fields that generate antiviral cytotoxic T lymphocytes ( CTLs) in association with LNDCs, in a model of cutaneous herpes simplex virus (HSV) infection. Although pDCs alone failed to induce CTLs, in vivo depletion of pDCs impaired CTL-mediated virus eradication. LNDCs from pDC-depleted mice showed impaired cluster formation with T cells and antigen presentation to prime CTLs. Transferring circulating pDC precursors from wild-type, but not CXCR3-deficient, mice to pDC-depleted mice restored CTL induction by impaired LNDCs. In vitro co-culture experiments revealed that pDCs provided help signals that recovered impaired LNDCs in a CD2- and CD40L-dependent manner. pDC-derived IFN-alpha further stimulated the recovered LNDCs to induce CTLs. Therefore, the help provided by pDCs for LNDCs in primary immune responses seems to be pivotal to optimally inducing anti-HSV CTLs.

DOI： 10.1084/jem.20041961

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While it is well-known that orally fed antigens induce systemic T cell tolerance ( oral tolerance), the mechanism by which this occurs, however, remains unclear. In the present study, we examined the role of splenic dendritic cells (DCs) in the process of oral tolerance induction and/or maintenance, by using an adoptive transfer system of antigen (Ag)-specific CD4(+) T cells from ovalbumin (OVA)-specific T cell receptor transgenic mice and DCs from OVA-fed BALB/c mice. Transfer of splenic DCs from OVA-fed mice reduced IL-2 productivity and the proliferative activity of pre-transferred Ag-specific CD4(+) T cells to ex vivo Ag stimulation. There were no changes in expression levels of costimulatory molecules on DCs from OVA-fed mice. Our results show that orally administered Ags induce systemic T cell unresponsiveness through splenic DCs without inducing cell division of T cells, thus providing evidence that splenic DCs are involved in oral tolerance induction.

DOI： 10.1023/B:

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Peyer's patch (PP) dendritic cells (DCs) have been shown to exhibit a distinct capacity to induce cytokine secretion from CD4(+) T cells compared with DCs in other lymphoid organs such as the spleen (SP). In this study, we investigated whether PP DCs are functionally different from DCs in the SP in their ability to induce Ab production from B cells. Compared with SP DCs, freshly isolated PP DCs induced higher levels of IgA secretion from naive B cells in DC-T cell-B cell coculture system in vitro. The IgA production induced by PP DCs was attenuated by neutralization of IL-6. In addition, the induction of IgA secretion by SP DCs, but not PP DCs, was further enhanced by the addition of exogenous IL-6. Finally, we demonstrated that only PP CD11b(+) DC subset secreted higher levels of IL-6 compared with other DC subsets in the PP and all SP DC populations, and that PP CD11b(+) DC induced naive B cells to produce higher levels of IgA compared with SP CD11b(+) DC. These results suggest a unique role of PP CD11b(+) DCs in enhancing IgA production from B cells via secretion of IL-6.

DOI： 10.4049/jimmunol.171.7.3684

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Language：Japanese   Publisher：(一社)日本病理学会  

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Language：Japanese   Publisher：(公社)日本薬学会  

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Language：Japanese   Publisher：(一社)日本病理学会  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

Web of Science

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Language：Japanese  

CiNii Books

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Other Link： http://search.jamas.or.jp/link/ui/2017082748

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J-GLOBAL

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J-GLOBAL

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CiNii Books

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Other Link： http://search.jamas.or.jp/link/ui/2013182755

Language：Japanese   Publisher：The Biophysical Society of Japan General Incorporated Association  

DOI： 10.2142/biophys.53.S163_4

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CiNii Books

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Other Link： http://search.jamas.or.jp/link/ui/2013090584

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PubMed

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J-GLOBAL

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Language：Japanese   Publishing type：Book review, literature introduction, etc.   Publisher：JAPANESE BIOCHEMICAL SOC  

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Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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