Toshiro Niki

Kagawa University, Takamatu, Kagawa, Japan

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Publications (67)298.16 Total impact

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    ABSTRACT: Gallbladder cancer (GBC) is the most common and aggressive type of biliary tract cancer. There are various histological types of GBC, and the vast majority of GBC cases are adenocarcinomas. Squamous and adenosquamous carcinomas are rare GBC subtypes that are traditionally considered to be more aggressive and to be associated with a poorer prognosis than adenocarcinoma. Galectin-9 (Gal-9), a tandem-repeat-type galectin, has been reported to induce apoptosis-mediated elimination of various cancers, including hepatocellular carcinoma, cholangiocarcinoma, and hematologic malignancies. Therefore, we investigated the antitumor effects of Gal-9 on GBC in vitro and in vivo. In our in vitro experiments, Gal-9 suppressed cell proliferation in various GBC cell lines but not in the OCUG-1 cell line, which represents a poorly differentiated type of adenosquamous carcinoma. Gal-9 induced the apoptosis of Gal-9-sensitive GBC cells by increasing the levels of caspase-cleaved keratin 18 and phosphorylated p53. However, Gal-9 did not affect the expression of various cell cycle-related proteins. In addition, Gal-9 suppressed tumor growth by implanted human GBC cells in a xenograft model. Furthermore, Gal-9 induced the phosphorylation of the Ephrin type-B receptor, and the microRNA (miRNA) expression profile was markedly altered by Gal-9. Based on these results, various miRNAs might contribute to the suppression of tumor growth. Our data reveal that Gal-9 suppresses the growth of GBC, possibly by inducing apoptosis and altering miRNA expression. Thus, Gal-9 might serve as a therapeutic agent for the treatment of GBC.
    No preview · Article · Jan 2016 · International Journal of Oncology
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    ABSTRACT: Fewer than 50% of patients with acute liver failure (ALF) recover spontaneously, and ALF has high mortality without liver transplantation. Kupffer cells have been reported to mediate liver inflammation during drug-induced injury. Galectin-9 is produced by Kupffer cells and has diverse roles in regulating immunity. We investigated whether plasma levels of galectin-9 are associated with outcomes of patients with ALF.
    No preview · Article · Oct 2015
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    ABSTRACT: Matricellular proteins such as osteopontin (OPN), galectin-9 (Gal-9), and tenascin-C (TN-C) are expressed not only under normal physiological conditions, but also during infection, inflammation, or tumorigenesis. We studied the levels of matricellular proteins in plasma to determine their diagnostic value as potential markers of tuberculosis (TB) activity. We found that levels of OPN and TN-C were higher in active TB patients compared to healthy individuals (HC) and latently infected (LTBI) individuals. Moreover, LTBI patients had higher OPN levels compared to HC. The Gal-9 levels did not differ significantly between groups. The levels of the matricellular proteins were higher in pleural fluid compared to their levels in the plasma of TB patient. Expression of matricellular proteins was also investigated in TB granulomas and in other granulomatous diseases. Positive OPN and Gal-9 staining was observed in TB and sarcoidosis granulomas, but not in Crohn's disease granuloma. The fibrotic ring around granulomas stained positive for TN-C in TB and sarcoidosis, but not in Crohn's disease. Of the three matricellular proteins studied, OPN and TN-C may serve as reliable plasma markers to monitor TB activity, whereas Gal-9 seems to be expressed more at the site of infection rather than in systemic circulation. This article is protected by copyright. All rights reserved.
    No preview · Article · Sep 2015 · Microbiology and Immunology
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    ABSTRACT: Cholangiocarcinoma is the most common biliary malignancy and the second most common hepatic malignancy after hepatocellular carcinoma (HCC). Galectin-9 (Gal-9) is a tandem-repeat-type galectin that has recently been shown to exert antiproliferative effects on cancer cells. Therefore, the present study evaluated the effects of Gal-9 on the proliferation of human cholangiocarcinoma cells in vitro as well as the microRNAs (miRNAs) associated with the antitumor effects of Gal-9. Gal-9 suppressed the proliferation of cholangiocarcinoma cell lines in vitro and the growth of human cholangiocarcinoma cell xenografts in nude mice. Our data further revealed that Gal-9 increased caspase‑cleaved keratin 18 (CCK18) levels, and the expression of cytochrome c increased in Gal-9-treated cholangiocarcinoma cell lines. These data suggested that Gal-9 induced cholangiocarcinoma cell apoptosis via the intrinsic apoptosis pathway mediated by caspase-dependent or -independent pathways. In addition, Gal-9 reduced the phosphorylation of the epidermal growth factor receptor (EGFR), insulin-like growth factor and insulin-like growth factor-1 receptor (IGF-1R), hepatocyte growth factor receptor and fibroblast growth factor receptor 3 (FGFR3). These findings suggest that Gal-9 can be a candidate of therapeutic target in the treatment of cholangiocarcinoma.
    No preview · Article · Aug 2015 · Oncology Reports
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    ABSTRACT: Oncogenic mutation of KRAS in colorectal cancer (CRC) confers resistance to both chemotherapy and EGFR-targeted therapy. We uncovered that KRAS mutant (KRASmut) CRC is uniquely sensitive to treatment with recombinant Galectin-9 (rGal-9), a recently established regulator of epithelial polarity. Upon treatment of CRC cells, rGal-9 rapidly internalizes via clathrin- and PKC/CRAF/MEK-dependent endocytosis and accumulates in the lysosomal compartment. Treatment with rGal-9 is accompanied by activation of frustrated autophagy in KRASmut CRC, but not in BRAFmut CRC. In KRASmut CRC, rGal-9 acts as a lysosomal inhibitor that inhibits autophagosome/lysosome fusion, leading to autophagosome accumulation, excessive lysosomal swelling and cell death. This antitumor activity of rGal-9 directly correlates with elevated basal autophagic flux in KRASmut cancer cells. Thus, rGal-9 has potent antitumor activity towards refractory KRASmut CRC cells that may be exploitable for therapeutic use.
    Full-text · Article · May 2015 · Autophagy
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    ABSTRACT: Galectin-9 (gal-9) is a multifunctional β-galactoside-binding lectin, frequently released in the extra-cellular medium, where it acts as a pleiotropic immune modulator. Despite its overall immunosuppressive effects, a recent study has reported a bimodal action of gal-9 on human resting blood T cells with apoptosis occurring in a majority of them, followed by a wave of activation and expansion of Th1 cells in the surviving population. Our knowledge of the signaling events triggered by exogenous gal-9 in T cells remains limited. One of these events is a cytosolic calcium (Ca2+) release reported in some murine and human T cells. The aim of this study was to investigate the contribution of Ca2+ mobilization to apoptotic and non-apoptotic effects of exogenous gal-9 in human T cells. We found that the T cell receptor (TCR)/CD3 complex and the Lck kinase were required for Ca2+ mobilization but not for apoptosis induction in Jurkat cells. These data were confirmed in human CD4+ T cells from peripheral blood: a specific Lck chemical inhibitor abrogated Ca2+ mobilization, but not apoptosis induction. Moreover, Lck activity was also required for the production of Th1-type cytokines, i.e. interleukine-2 and interferon-γ, which resulted from gal-9 stimulation in peripheral CD4+ T cells. These findings indicate that gal-9 acts on T cells by two distinct pathways: one mimicking antigen-specific activation of the TCR with a mandatory contribution of proximal elements of the TCR complex, especially Lck, and another resulting in apoptosis which is independent of this complex. Copyright © 2015, The American Society for Biochemistry and Molecular Biology.
    Full-text · Article · May 2015 · Journal of Biological Chemistry
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    ABSTRACT: Background: Regulatory T cells (Treg) and tumor-exosomes are thought to play a role in preventing the rejection of malignant cells in patients bearing nasopharyngeal carcinoma (NPC). Methods: Treg recruitment by exosomes derived from NPC cell lines (C15/C17-Exo), exosomes isolated from NPC patients’ plasma (Patient-Exo), and CCL20 were tested in vitro using Boyden chamber assays and in vivo using a xenograft SCID mouse model (n = 5), both in the presence and absence of anti-CCL20 monoclonal antibodies (mAb). Impact of these NPC exosomes (NPC-Exo) on Treg phenotype and function was determined using adapted assays (FACS, Q-PCR, ELISA, and MLR). Experiments were performed in comparison with exosomes derived from plasma of healthy donors (HD-Exo). The Student’s t test was used for group comparisons. All statistical tests were two-sided. Results: CCL20 allowed the intratumoral recruitment of human Treg. NPC-Exo also facilitated Treg recruitment (3.30±0.34 fold increase, P < .001), which was statistically significantly inhibited (P < .001) by an anti-CCL20 blocking mAb. NPC-Exo also recruited conventional CD4+CD25- T cells and mediated their conversion into inhibitory CD4+CD25high cells. Moreover, NPC-Exo enhanced (P = .0048) the expansion of human Treg, inducing the generation of Tim3Low Treg with increased expression of CD25 and FOXP3. Finally, NPC-Exo induced an overexpression of cell markers associated with Treg phenotype, properties and recruitment capacity. For example, GZMB mean fold change was 21.45±1.75 (P < .001). These results were consistent with a stronger suppression of responder cells’ proliferation and the secretion of immunosuppressive cytokines (IL10, TGFB1). Conclusion: Interactions between NPC-Exo and Treg represent a newly defined mechanism that may be involved in regulating peripheral tolerance by tumors and in supporting immune evasion in human NPC.
    Full-text · Article · May 2015 · JNCI Journal of the National Cancer Institute
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    ABSTRACT: Galectin-9 (Gal-9) has gained attention as a multifaceted player in adaptive and innate immunity. To elucidate the role of Gal-9, we used a mouse model of partial liver ischemia reperfusion injury (IRI) with wild type and Gal-9 knockout mice as well as a recombinant Gal-9 protein. We found that the expression of Gal-9 was enhanced endogenously in liver especially hepatocytes and Kupffer cells during mouse liver warm IRI which causes the massive destruction of liver tissue. Gal-9 was released into the extracellular space in liver and the highest in plasma 1h after reperfusion. The present study elucidates a novel role of Gal-9 signaling in mouse liver IRI, by using Gal-9 deficient mice and a stable form of recombinant Gal-9 protein. In the circumstance of Gal-9 absence, liver damage due to ischemia and reperfusion (IR) exacerbated the severity as compared with wild type. On the other hand, exogenously-administered recombinant Gal-9 significantly ameliorated hepatocellular damage. It decreased local infiltration of the inflammatory cells such as T cells, neutrophils and macrophages, and reduced the expression of pro-inflammatory cytokines/chemokines, then strongly suppressed apoptosis of the liver cells. Interestingly, severe liver damage due to IR in Gal-9 knockout mice was improved by administration of recombinant Gal-9. In conclusion, Gal-9 engagement ameliorated local inflammation and liver damage induced by IR, and the present study suggests a significant role of Gal-9 in the maintenance of hepatic homeostasis. Hence, targeting Gal-9 represents a novel approach to protect inflammation such as liver IRI. Exogenous Gal-9 treatment will be a new therapeutic strategy against innate immunity-dominated liver tissue damage. This article is protected by copyright. All rights reserved. © 2015 American Association for the Study of Liver Diseases.
    No preview · Article · Apr 2015 · Liver Transplantation
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    ABSTRACT: Galectin-9, a soluble β-galactoside-binding animal lectin, evokes apoptosis in various human cancer cell lines. The galectin-9 antitumor effect against hepatocellular carcinoma (HCC) is, however, unknown. We investigated whether galectin-9 suppresses HCC growth in vitro and in vivo. We assessed the antitumor effect of galectin-9 on HCC cells by conducting WST-8 assay in vitro and xenograft model analysis in vivo. Galectin-9-induced apoptosis was evaluated by FACS and ELISA in vitro and by TUNEL stain in vivo. Cell cycle alteration was profiled by FACS. Caspases were profiled by colorimetry. MicroRNAs related to the galectin-9 antitumor effects were determined using microarrays, and their antitumor effect was confirmed in a transfection study in vitro. The expression levels of the target proteins of the miRNAs extracted above were analyzed by western blot analysis. To summarize the results, galectin-9 inhibited the growth of the HCC cell lines HLE and Li-7 in vitro and Li-7 in vivo inducing apoptosis. Cell cycle turnover was not arrested in HLE and Li-7 cells in vitro. miR‑1246 was similarly extracted both in vitro and in vivo, which sensitized Li-7 cells to apoptosis when transfected into the cells. DYRK1A, a target protein of miR‑1246 was downregulated in Li-7 cells. Caspase-9 was upregulated in Li-7 cells in vitro and in vivo. In conclusion, galectin-9 inhibited the growth of HCC cells by apoptosis, but not cell cycle arrest, in vitro and in vivo. miR‑1246 mediated signals of galectin-9, possibly through miR‑1246-DYRK1A-caspase-9 axis. Galectin-9 might be a candidate agent for HCC chemotherapy.
    No preview · Article · Mar 2015 · International Journal of Oncology
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    ABSTRACT: Non-alcoholic steatohepatitis (NASH) is one of the most common causes of chronic liver disease and is considered to be a causative factor of cryptogenic cirrhosis and hepatocellular carcinoma. microRNAs (miRNAs) are small non-coding RNAs that negatively regulate messenger RNA (mRNA). Recently, it was demonstrated that the aberrant expression of certain miRNAs plays a pivotal role in liver disease. The aim of the present study was to evaluate changes in miRNA profiles associated with metformin treatment in a NASH model. Eight-week-old male mice were fed a methionine- and choline-deficient (MCD) diet alone or with 0.08% metformin for 15 weeks. Metformin significantly downregulated the level of plasma transaminases and attenuated hepatic steatosis and liver fibrosis. The expression of miRNA-376a, miRNA‑127, miRNA-34a, miRNA-300 and miRNA-342-3p was enhanced among the 71 upregulated miRNAs, and the expression of miRNA-122, miRNA-194, miRNA-101b and miRNA-705 was decreased among 60 downregulated miRNAs in the liver of MCD-fed mice when compared with control mice. Of note, miRNA profiles were altered following treatment with metformin in MCD-fed mice. miRNA-376a, miRNA‑127, miRNA-34a, miRNA-300 and miRNA-342-3p were downregulated, but miRNA-122, miRNA-194, miRNA‑101b and miRNA-705 were significantly upregulated in MCD-fed mice treated with metformin. miRNA profiles were altered in MCD-fed mice and metformin attenuated this effect on miRNA expression. Therefore, miRNA profiles are a potential tool that may be utilized to clarify the mechanism behind the metformin-induced improvement of hepatic steatosis and liver fibrosis. Furthermore, identification of targetable miRNAs may be used as a novel therapy in human NASH.
    Full-text · Article · Feb 2015 · International Journal of Molecular Medicine
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    Full-text · Dataset · Dec 2014
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    ABSTRACT: Tuberculosis (TB) is the second most common cause of death from infectious diseases and results in high socioeconomic losses to many countries. Proper diagnosis is the first step in TB eradication. To develop a rapid, simple, and accurate diagnostic TB test and to characterize the prevalence of Mycobacterium tuberculosis (MTB) genotypes and immune profiles of TB patients, a total of 37 TB patients and 30 healthy control (HC) from Metro Manila were enrolled. Loop-mediated isothermal amplification (LAMP) reliably detected MTB infection. Manila genotype was identified by spoligotyping method in all TB patients. Osteopontin (OPN), interferon- γ -induced protein 10 kDa (IP-10), and neutrophil counts were found to reflect the acute stage of MTB infection. The sensitivity and specificity were 94.6% and 93.3%, respectively, for both OPN and IP-10, and they were 83.8% and 78.6%, respectively, for neutrophils. The combination of OPN, IP-10, neutrophil count, IL-6, IL-8, TNF- α , MCP-1, platelets, galectin-9, and leukocyte count correctly identifies all the HC and 96.3% of TB patients. LAMP method may serve as a rapid, supportive method in addition to time-consuming culture methods. OPN, IP-10, and neutrophil counts are useful in detecting MTB infection and may have utility in monitoring the course of the disease.
    Full-text · Article · Oct 2014 · Mediators of Inflammation
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    ABSTRACT: Biologics to TNF family receptors are prime candidates for therapy of immune disease. Whereas recent studies have highlighted a requirement for Fcγ receptors in enabling the activity of CD40, TRAILR, and GITR when engaged by antibodies, other TNFR molecules may be controlled by additional mechanisms. Antibodies to 4-1BB (CD137) are currently in clinical trials and can both augment immunity in cancer and promote regulatory T cells that inhibit autoimmune disease. We found that the action of agonist anti-4-1BB in suppressing autoimmune and allergic inflammation was completely dependent on Galectin-9 (Gal-9). Gal-9 directly bound to 4-1BB, in a site distinct from the binding site of antibodies and the natural ligand of 4-1BB, and Gal-9 facilitated 4-1BB aggregation, signaling, and functional activity in T cells, dendritic cells, and natural killer cells. Conservation of the Gal-9 interaction in humans has important implications for effective clinical targeting of 4-1BB and possibly other TNFR superfamily molecules.
    Full-text · Article · Jun 2014 · Journal of Experimental Medicine
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    ABSTRACT: Galectin-9 (Gal-9) is a β-galactosidase-binding lectin that promotes apoptosis, tissue inflammation, T cell immune exhaustion, and alters HIV infection in part through engagement with the T cell immunoglobulin mucin domain-3 (Tim-3) receptor and protein disulphide isomerases (PDI). Gal-9 was initially thought to be an eosinophil attractant, but is now known to mediate multiple complex signaling events that affect T cells in both an immunosuppressive and inflammatory manner. To understand the kinetics of circulating Gal-9 levels during HIV infection we measured Gal-9 in plasma during HIV acquisition, in subjects with chronic HIV infection with differing virus control, and in uninfected individuals. During acute HIV infection, circulating Gal-9 was detected as early as 5 days after quantifiable HIV RNA and tracked plasma levels of IL-10, TNF-α, and IL-1β. In chronic HIV infection, Gal-9 levels positively correlated with plasma HIV RNA levels (r= 0.29; p= 0.023), and remained significantly elevated during suppressive anti-retroviral therapy (median: 225.3 pg/ml) and in elite controllers (263.3 pg/ml) compared to age-matched HIV-uninfected controls (54 pg/ml). Our findings identify Gal-9 as a novel component of the first wave of the cytokine storm in acute HIV infection that is sustained at elevated levels in virally suppressed subjects and suggest that Gal-9:Tim-3 crosstalk remains active in elite controllers and ARV suppressed subjects, potentially contributing to ongoing inflammation and persistent T cell dysfunction.
    Full-text · Article · Apr 2014 · AIDS research and human retroviruses
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    ABSTRACT: Anti-glomerular basement membrane glomerulonephritis (anti-GBM GN) is a Th1- and Th17-predominant autoimmune disease. Galectin-9 (Gal-9), identified as the ligand of Tim-3, functions in diverse biological processes and leads to the apoptosis of CD4+Tim-3+ T cells. It is still unclear how Gal-9 regulates the functions of Th1 and Th17 cells and prevents renal injury in anti-GBM GN. In this study, Gal-9 was administered to anti-GBM GN mice for 7 days. We found that Gal-9 retarded the increase of Scr, ameliorated renal tubular injury and reduced the formation of crescents. The infiltration of Th1 and Th17 cells into the spleen and kidneys significantly decreased in Gal-9-treated nephritic mice. The reduced infiltration of Th1 and Th17 cells might be associated with the down-regulation of CCL-20, CXCL-9 and CXCL-10 mRNAs in the kidney. In parallel, the blood levels of IFN-γ and IL-17A declined in Gal-9-treated nephritic mice at day 21 and day 28. In addition, an enhanced Th2 cell-mediated immune response was observed in the kidneys of nephritic mice after a 7-day injection of Gal-9. In conclusion, the protective role of Gal-9 in anti-GBM GN is associated with the inhibition of Th1 and Th17 cell-mediated immune responses and enhanced Th2 immunity in the kidney.
    Full-text · Article · Jan 2014 · AJP Renal Physiology
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    ABSTRACT: Galectin-9 (Gal-9), a lectin having a β-galactoside-binding domain, can induce apoptosis of Th1 cells by binding to TIM-3. In addition, Gal-9 inhibits IgE/Ag-mediated degranulation of mast cell/basophilic cell lines by binding to IgE, thus blocking IgE/Ag complex formation. However, the role of Gal-9 in mast cell function in the absence of IgE is not fully understood. Here, we found that recombinant Gal-9 directly induced phosphorylation of Erk1/2 but not p38 MAPK in a human mast cell line, HMC-1, which does not express FcεRI. Gal-9 induced apoptosis and inhibited PMA/ionomycin-mediated degranulation of HMC-1 cells. On the other hand, Gal-9 induced cytokine and/or chemokine production by HMC-1 cells, dependent on activation of ERK1/2 but not p38 MAPK. In addition, the lectin activity of Gal-9 was required for Gal-9-mediated cytokine secretion by HMC-1 cells. These observations suggest that Gal-9 has dual properties as both a regulator and an activator of mast cells.
    Full-text · Article · Jan 2014 · PLoS ONE
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    ABSTRACT: Galectin-9 ameliorates various inflammatory conditions including autoimmune diseases by regulating T cell and macrophage/dendritic cell (DC) functions. However, the effect of galectin-9 on polymicrobial sepsis has not been assessed. We induced polymicrobial sepsis by cecal ligation and puncture (CLP) in mice. The survival rate was compared between galectin-9- and PBS-treated CLP mice. An ELISA was used to compare the levels of various cytokines in the plasma and culture supernatants. Fluorescence-activated cell sorting analysis was further performed to compare the frequencies of subpopulations of spleen cells. Galectin-9 exhibited a protective effect in polymicrobial sepsis as demonstrated in galetin-9 transgenic mice and therapeutic galectin-9 administration. In contrast, such effect was not observed in nude mice, indicating the involvement of T cells in galectin-9-mediated survival prolongation. Galectin-9 decreased TNFalpha, IL-6, IL-10 and, high mobility group box 1 (HMGB1) and increased IL-15 and IL-17 plasma and spleen levels. Galectin-9 increased the frequencies of natural killer T (NKT) cells and PDCA-1+ CD11c+ macrophages (pDC-like macrophages) but did not change the frequency of CD4 or CD8 T cells, [unknown][unknown]T cells or conventional DC. As expected, galectin-9 decreased the frequency of Tim-3+ CD4 T cells, most likely Th1 and Th17 cells. Intriguingly, many spleen NK1.1+ NKT cells and pDC-like macrophages expressed Tim-3. Galectin-9 increased the frequency of Tim-3-expressing NK1.1+ NKT cells and pDC-like macrophages. Galectin-9 further increased IL-17+ NK1.1+ NKT cells. These data suggest that galectin-9 exerts therapeutic effects on polymicrobial sepsis, possibly by expanding NKT cells and pDC-like macrophages and by modulating the production of early and late proinflammatory cytokines.
    Full-text · Article · Dec 2013 · Critical care (London, England)
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    ABSTRACT: Background: Viral respiratory infection is the most common cause of acute asthma exacerbation in patients with stable asthma. The replication of most respiratory viruses requires the generation of double-stranded RNA (dsRNA), resulting in the activation of host immune responses. Synthetic dsRNA, polyinosinic-polycytidylic acid (PolyIC), mimics the effects of viruses in various cell types. To evaluate new therapies for mite antigen-induced chronic asthma, we developed an acute exacerbation model of mouse chronic asthma using mite antigen and PolyIC. We also examined the preventive effects of recombinant galectin-9 (Gal-9) on acute asthma exacerbation in this model. Methods: Airway hyperresponsiveness (AHR) was examined to evaluate the exacerbation of chronic asthma. To analyze airway inflammation, the numbers of inflammatory cells and concentrations of cytokines in the bronchoalveolar lavage fluid (BALF) were estimated by flow cytometry and enzyme-linked immunosorbent assay, respectively. Results: AHR was accelerated by intranasal administration of PolyIC in addition to mite antigen. Levels of cytokines that contribute to AHR, including interferon-γ, tumor necrosis factor-α, and RANTES (CCR5), and of Gal-9 in the BALF were elevated in this acute asthma exacerbation mouse model. Intranasal administration of recombinant Gal-9 reduced the PolyIC-induced AHR and levels of these cytokines in the BALF. Further, Gal-9 suppressed the production of cytokines induced by PolyIC in the alveolar macrophages. CONCLUSIONS. Our findings demonstrated that exogenous Gal-9 suppressed dsRNA-induced AHR in an acute exacerbation model of chronic asthma in mice, and suggest that recombinant Gal-9 could be therapeutically effective for preventing acute asthma exacerbation.
    No preview · Article · Nov 2013 · Experimental Lung Research
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    ABSTRACT: Dengue virus (DENV) infection remains a major public health burden worldwide. Soluble mediators may play a critical role in the pathogenesis of acute DENV infection. Galectin-9 (Gal-9) is a soluble β-galactoside-binding lectin, with multiple immunoregulatory and inflammatory properties. To investigate plasma Gal-9 levels as a biomarker for DENV infection. We enrolled 65 DENV infected patients during the 2010 epidemic in the Philippines and measured their plasma Gal-9 and cytokine/chemokine levels, DENV genotypes, and copy number during the critical and recovery phases of illness. During the critical phase, Gal-9 levels were significantly higher in DENV infected patients compared to healthy or those with non-dengue febrile illness. The highest Gal-9 levels were observed in dengue hemorrhagic fever (DHF) patients (DHF: 2464pg/ml; dengue fever patients (DF): 1407pg/ml; non-dengue febrile illness: 616pg/ml; healthy: 196pg/ml). In the recovery phase, Gal-9 levels significantly declined from peak levels in DF and DHF patients. Gal-9 levels tracked viral load, and were associated with multiple cytokines and chemokines (IL-1α, IL-8, IP-10, and VEGF), including monocyte frequencies and hematologic variables of coagulation. Further discriminant analyses showed that eotaxin, Gal-9, IFN-α2, and MCP-1 could detect 92% of DHF and 79.3% of DF, specifically (P<0.01). Gal-9 appears to track DENV inflammatory responses, and therefore, it could serve as an important novel biomarker of acute DENV infection and disease severity.
    Full-text · Article · Oct 2013 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
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    ABSTRACT: Human monocytes/macrophages (M/MФ) of the innate immunity sense and respond to microbial products via specific receptor coupling with stimulatory (such as TLR) and inhibitory (such as Tim-3) receptors. Current models imply that Tim-3 expression on M/MØ can deliver negative signaling to TLR-mediated IL-12 expression through trans association with its ligand Galectin-9 (Gal-9) presented by other cells. However, Gal-9 is also expressed within M/MØ, and the effect of intracellular Gal-9 on Tim-3 activities and inflammatory responses in the same M/MØ remains unknown. In this study, our data suggest that Tim-3 and IL-12/IL-23 gene transcriptions are regulated by enhanced or silenced Gal-9 expression within monocytes through synergizing with TLR signaling. Additionally, TLR activation facilitates Gal-9/Tim-3 cis association within the same M/MØ to differentially regulate IL-12/IL-23 expressions through STAT-3 phosphorylation. These results reveal a ligand (Gal-9) compartment-dependent regulatory effect on receptor (Tim-3) activities and inflammatory responses via TLR pathways-a novel mechanism underlying cellular responses to external or internal cues.
    Preview · Article · Aug 2013 · PLoS ONE