DcR3 suppresses influenza virus-induced macrophage activation and attenuates pulmonary inflammation and lethality

Influenza A virus (IAV) infects macrophages and stimulates innate immunity receptors and sensors to produce proinflammatory cytokines and chemokines, which are responsible for IAV-induced pulmonary inflammation and injury. Decoy receptor 3 (DcR3) is a soluble protein belonging to the tumor necrosis factor receptor superfamily (TNFRSF), and is able to skew macrophage differentiation into an M2 phenotype. We demonstrated that DcR3 attenuated IAV-induced secretion of proinflammatory cytokines and chemokine from macrophages, and mitigated pulmonary infiltration and reduce lethality. Proteome-wide phosphoproteomic mapping revealed that DcR3 not only activated STK10, a negative regulator of cell migration, but also inactivated PKC-α, which are crucial for the activation of ERK and JNK in human macrophages. Furthermore, less pulmonary infiltration with lower levels of proinflammatory cytokines and chemokine in bronchoalveolar lavage fluid (BALF) were observed in DcR3-transgenic mice. Moreover, recombinant DcR3.Fc and heparan sulfate proteoglycan binding domain of DcR3.Fc (HBD.Fc) fusion proteins attenuated weight loss and protected mice from IAV-induced lethality. Thus, DcR3-mediated protection is not only via suppression of proinflammatory cytokine and chemokine release, but also via activation of STK10 to inhibit cell infiltration. DcR3 fusion proteins may become therapeutic agents to protect host from IAV-induced lethality in the future.

KEY MESSAGE

• DcR3 suppresses IAV-induced cytokine secretion.• DcR3 inhibits IAV-induced JNK and ERK activation in human macrophages.• DcR3 downregulates TLR3 and 7 expressions in human macrophages.• DcR3 protects mice from IAV-induced lethality.

Concomitant inhibition of oxidative stress and angiogenesis by chronic hydrogen-rich saline and N-acetylcysteine treatments improves systemic, splanchnic and hepatic hemodynamics of cirrhotic rats

AIM

In cirrhosis, increased oxidative stress leads to systemic and splanchnic hyperdynamic circulation, splanchnic angiogenesis, portosystemic collateral formation, hepatic endothelial dysfunction, increased intrahepatic resistance and the subsequent portal hypertension. Like N-acetylcysteine, hydrogen-rich saline is a new documented antioxidant with the potential to treat the complications of liver diseases.

METHODS

In this study, hemodynamics, splanchnic angiogenesis and hepatic endothelial dysfunction were measured in common bile duct ligation (BDL)-cirrhotic rats receiving 1-month treatment of vehicle, N-acetylcysteine and hydrogen-rich saline immediately after BDL. Additionally, acute effects of N-acetylcysteine and hydrogen-rich saline on vascular endothelial growth factor (VEGF)-induced tubule formation and migration of human umbilical vein endothelial cells (HUVEC) were also evaluated.

RESULTS

The data indicate that 1-month treatment of N-acetylcysteine or hydrogen-rich saline significantly ameliorated systemic and splanchnic hyperdynamic circulation, corrected hepatic endothelial dysfunction, and decreased intrahepatic resistance and mesenteric angiogenesis by inhibiting inflammatory cytokines, nitric oxide, VEGF and reducing mesenteric oxidative stress in cirrhotic rats. In vivo studies revealed that acute co-incubation of N-acetylcysteine or hydrogen-rich saline with VEGF effectively suppressed VEGF-induced angiogenesis and migration of HUVEC accompanied by decreasing of oxidative stress and inflammatory cytokines.

CONCLUSION

Both hydrogen-rich saline and N-acetylcysteine alleviate portal hypertension, the severity of portosystemic collaterals, mesenteric angiogenesis, hepatic endothelial dysfunction and intrahepatic resistance in cirrhotic rats. N-Acetylcysteine and the new antioxidant, hydrogen-rich saline are potential treatments for the complications of cirrhosis.

Syk is involved in NLRP3 inflammasome-mediated caspase-1 activation through adaptor ASC phosphorylation and enhanced oligomerization

NLRP3 is the most crucial member of the NLR family, as it detects the existence of pathogen invasion and self-derived molecules associated with cellular damage. Several studies have reported that excessive NLRP3 inflammasome-mediated caspase-1 activation is a key factor in the development of diseases. Recent studies have reported that Syk is involved in pathogen-induced NLRP3 inflammasome activation; however, the detailed mechanism linking Syk to NLRP3 inflammasome remains unclear. In this study, we showed that Syk mediates NLRP3 stimuli-induced processing of procaspase-1 and the consequent activation of caspase-1. Moreover, the kinase activity of Syk is required to potentiate caspase-1 activation in a reconstituted NLRP3 inflammasome system in HEK293T cells. The adaptor protein ASC bridges NLRP3 with the effector protein caspase-1. Herein, we find that Syk can associate directly with ASC and NLRP3 by its kinase domain but interact indirectly with procaspase-1. Syk can phosphorylate ASC at Y146 and Y187 residues, and the phosphorylation of both residues is critical to enhance ASC oligomerization and the recruitment of procaspase-1. Together, our results reveal a new molecular pathway through which Syk promotes NLRP3 inflammasome formation, resulting from the phosphorylation of ASC. Thus, the control of Syk activity might be effective to modulate NLRP3 inflammasome activation and treat NLRP3-related immune diseases.

Long-term cannabinoid type 2 receptor agonist therapy decreases bacterial translocation in rats with cirrhosis and ascites

BACKGROUND & AIMS

Intestinal hyperpermeability, impaired peritoneal macrophages (PMs) phagocytosis, and bacterial translocation (BT), resulting in increased systemic and local infection/inflammation such as spontaneous bacterial peritonitis (SBP) together with increased tumor necrosis factor-α (TNFα) levels, are all implicated in the pathogenesis of cirrhosis-related complications. Manipulation of the cannabinoid receptors (CB1R and CB2R), which are expressed on the gut mucosa and PMs, has been reported to modulate intestinal inflammation and systemic inflammatory cytokine release. Our study aims to explore the effects of chronic CB1R/CB2R agonist/antagonist treatments on relevant abnormalities in cirrhotic ascitic rats.

METHODS

Vehicle, archidonyl-2-chloroethylamide (ACEA, CB1R agonist), JWH133 (CB2R agonist), and AM630 (CB2R antagonist) were given to thioacetamide (TAA) and common bile duct ligation (BDL) cirrhotic rats with ascites for two weeks and various measurement were performed.

RESULTS

Compared to sham rats, CB2Rs were downregulated in cirrhotic rat intestines and PMs. The two-week JWH133 treatment significantly decreased systemic/intestinal oxidative stress, TNFα and inflammatory mediators, infection, intestinal mucosal damage and hyperpermeability; the JWH133 treatment also decreased bacterial overgrowth/adhesion, BT and SBP, upregulated intestinal tight junctions and downregulated the PM TNFα receptor/NFκBp65 protein expression in cirrhotic rats. Acute and chronic JWH133 treatment corrected the TNFα-induced suppression of phagocytosis of cirrhotic rat PMs, which then could be reversed by concomitant AM630 treatment.

CONCLUSIONS

Our study suggests that CB2R agonists have the potential to treat BT and various relevant abnormalities through inhibition of systemic/intestinal oxidative stress, inflammatory cytokines and TNFα release in cirrhosis. Overall, the chronic CB2R agonist treatment affects multiple approach mechanisms, and its direct effect on the hyperdynamic circulation is only minor.

A novel TLR2-triggered signalling crosstalk synergistically intensifies TNF-mediated IL-6 induction

Toll-like receptors (TLR) recognize pathogens and trigger the production of vigorous pro-inflammatory cytokines [such as tumour necrosis factor (TNF)] that induce systemic damages associated with sepsis and chronic inflammation. Cooperation between signals of TLR and TNF receptor has been demonstrated through the participation of TNF receptor 1 (TNFR) adaptors in endotoxin tolerance. Here, we identify a TLR2-mediated synergy, through a MyD88-independent crosstalk, which enhances subsequent TNF-mediated nuclear factor-kappa B activation and interleukin-6 induction. Membrane-associated adaptor MAL conduces the link between TNF receptor-associated factor 6 (TRAF6) and TNFR-associated death domain, leading to a distinctive K63-ubiquitinylated TRAF6 recruitment into TNFR complex. In summary, our results reveal a novel route of TLR signal that synergistically amplifies TNF-mediated responses, indicating an innovative target for inflammation manipulation.

TREM-1 regulates macrophage polarization in ureteral obstruction

Chronic kidney disease (CKD) is an emerging worldwide public health problem. Inflammatory cell infiltration and activation during the early stages in injured kidneys is a common pathologic feature of CKD. Here, we determined whether an important inflammatory regulator, triggering receptor expressed on myeloid cells (TREM)-1, is upregulated in renal tissues collected from mouse ureteral obstruction-induced nephritis. TREM-1 is crucial for modulating macrophage polarization, and has a pivotal role in mediating tubular injury and interstitial collagen deposition in obstructive nephritis. Lysates from nephritic kidneys triggered a TREM-1-dependent M1 polarization ex vivo, consistent with the observation that granulocyte-macrophage colony-stimulating factor (GM-CSF)-derived M1 macrophages express higher levels of TREM-1 in comparison with M-CSF-derived cells. Moreover, agonistic TREM-1 cross-link significantly strengthens the inductions of iNOS and GM-CSF in M1 cells. These observations are validated by a strong clinical correlation between infiltrating TREM-1-expressing/iNOS-positive macrophages and renal injury in human obstructive nephropathy. Thus, TREM-1 may be a potential diagnostic and therapeutic target in human kidney disease.

The surface carbohydrates of the Echinococcus granulosus larva interact selectively with the rodent Kupffer cell receptor

The larvae of the cestodes belonging to the genus Echinococcus dwell primarily in mammalian liver. They are protected by the laminated layer (LL), an acellular mucin-based structure. The glycans decorating these mucins constitute the overwhelming majority of molecules exposed by these larvae to their hosts. However, their decoding by host innate immunity has not been studied. Out of 36 mammalian innate receptors with carbohydrate-binding domains, expressed as Fc fusions, only the mouse Kupffer cell receptor (KCR; CLEC4F) bound significantly to the Echinococcus granulosus LL mucins. The receptor also bound the Echinococcus multilocularis LL. Out of several synthetic glycans representing Echinococcus LL structures, the KCR bound strongly in particular to those ending in Galα1-4Galβ1-3 or Galα1-4Galβ1-4GlcNAc, both characteristic LL carbohydrate motifs. LL carbohydrates may be optimized to interact with the KCR, expressed only in liver macrophages, cells known to contribute to the tolerogenic antigen presentation that is characteristic of this organ.

Distinct regulation of dengue virus-induced inflammasome activation in human macrophage subsets

Macrophages (Mϕ) are the major source of inflammatory cytokines and are target cells for dengue virus (DV) replication. However, Mϕ are heterogeneous and their phenotypic and functional diversities are influenced by cytokines that regulate their differentiation, tissue distribution, and defense against invading pathogens. In vitro, human primary macrophages are derived from peripheral blood CD14⁺ monocytes in the presence of macrophage colony-stimulating factor (M-CSF) or granulocyte macrophage colony-stimulating factor (GM-CSF). These are essential for developing tissue/resting macrophages (M-Mϕ) and inflammatory macrophages (GM-Mϕ), respectively. While IFN production is similar between M-Mϕ and GM-Mϕ, M-Mϕ cannot produce IL-1β after DV infection. In contrast, GM-Mϕ is more susceptible to DV infection and DV triggers CLEC5A in GM-Mϕ to activate NLRP3 inflammasomes, which in turn release IL-18 and IL-1β that are critical for Th17 activation and contribute to disease severity. Thus, GM-Mϕ is more representative than M-Mϕ for investigating inflammasome activation in dengue infection, and is invaluable for revealing the molecular mechanism of pathogen-induced inflammatory reaction. Distinct phenotypes of macrophage subsets under the influence of M-CSF and GM-CSF raise the question of optimal conditions for culturing primary macrophages to study host-pathogen interaction.

CLEC4F is an inducible C-type lectin in F4/80-positive cells and is involved in alpha-galactosylceramide presentation in liver

CLEC4F, a member of C-type lectin, was first purified from rat liver extract with high binding affinity to fucose, galactose (Gal), N-acetylgalactosamine (GalNAc), and un-sialylated glucosphingolipids with GalNAc or Gal terminus. However, the biological functions of CLEC4F have not been elucidated. To address this question, we examined the expression and distribution of murine CLEC4F, determined its binding specificity by glycan array, and investigated its function using CLEC4F knockout (Clec4f-/-) mice. We found that CLEC4F is a heavily glycosylated membrane protein co-expressed with F4/80 on Kupffer cells. In contrast to F4/80, CLEC4F is detectable in fetal livers at embryonic day 11.5 (E11.5) but not in yolk sac, suggesting the expression of CLEC4F is induced as cells migrate from yolk cells to the liver. Even though CLEC4F is not detectable in tissues outside liver, both residential Kupffer cells and infiltrating mononuclear cells surrounding liver abscesses are CLEC4F-positive upon Listeria monocytogenes (L. monocytogenes) infection. While CLEC4F has strong binding to Gal and GalNAc, terminal fucosylation inhibits CLEC4F recognition to several glycans such as Fucosyl GM1, Globo H, Bb3∼4 and other fucosyl-glycans. Moreover, CLEC4F interacts with alpha-galactosylceramide (α-GalCer) in a calcium-dependent manner and participates in the presentation of α-GalCer to natural killer T (NKT) cells. This suggests that CLEC4F is a C-type lectin with diverse binding specificity expressed on residential Kupffer cells and infiltrating monocytes in the liver, and may play an important role to modulate glycolipids presentation on Kupffer cells.

EGFR-driven up-regulation of decoy receptor 3 in keratinocytes contributes to the pathogenesis of psoriasis

Decoy receptor 3 (DcR3) is a soluble receptor of Fas ligand (FasL), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A) and plays pleiotropic roles in many inflammatory and autoimmune disorders and malignant diseases. In cutaneous biology, DcR3 is expressed in primary human epidermal keratinocytes and is upregulated in skin lesions in psoriasis, which is characterized by chronic inflammation and angiogenesis. However, the regulatory mechanisms of DcR3 over-expression in skin lesions of psoriasis are unknown. Here, we demonstrate that DcR3 can be detected in both dermal blood vessels and epidermal layers of psoriatic skin lesions. Analysis of serum samples showed that DcR3 was elevated, but FasL was downregulated in psoriatic patients compared with normal individuals. Additional cell studies revealed a central role of epidermal growth factor receptor (EGFR) in controlling the basal expression of DcR3 in keratinocytes. Activation of EGFR by epidermal growth factor (EGF) and transforming growth factor (TGF)-α strikingly upregulated DcR3 production. TNF-αenhanced DcR3 expression in both keratinocytes and endothelial cells compared with various inflammatory cytokines involved in psoriasis. Additionally, TNF-α-enhanced DcR3 expression in keratinocytes was inhibited when EGFR was knocked down or EGFR inhibitor was used. The NF-κB pathway was critically involved in the molecular mechanisms underlying the action of EGFR and inflammatory cytokines. Collectively, the novel regulatory mechanisms of DcR3 expression in psoriasis, particularly in keratinocytes and endothelial cells, provides new insight into the pathogenesis of psoriasis and may also contribute to the understanding of other diseases that involve DcR3 overexpression.

The serologic decoy receptor 3 (DcR3) levels are associated with slower disease progression in HIV-1/AIDS patients

BACKGROUND/PURPOSE

The decoy receptor 3 (DcR3) is a member of the tumor necrosis factor receptor (TNFR) super-family. It counteracts the biological effects of Fas ligands and inhibits apoptosis. The goals of this study were to understand the associations between serologic DcR3 (sDcR3) levels and different human immunodeficiency virus type 1 (HIV-1) subtypes, as well as the AIDS disease progression.

METHODS

Serum samples from 61 HIV/AIDS patients, who had been followed up every 6 months for 3 years, were collected. sDcR3 levels were quantified using an enzyme immunoassay (EIA).

RESULTS

The sDcR3 levels in patients with HIV-1 subtype B were significantly higher than those in patients infected with subtype CRF01_AE (p < 0.001). In addition, multivariable linear mixed model analysis demonstrated that HIV-1 subtype B and slow disease progression were associated with higher levels of sDcR3, adjusting for potential predictors (p = 0.0008 and 0.0455, respectively).

CONCLUSION

HIV-1-infected cells may gain a survival advantage by activating DcR3, which prevents infected cell detection by the host immune system. These data indicate that the sDcR3 level is a biomarker for AIDS disease progression.

Apoptosis-associated biomarkers in tuberculosis: promising for diagnosis and prognosis prediction

Background

Apoptosis-associated biomarkers are rarely studied, especially their role in predicting the development of tuberculosis (TB) from latent TB infection and in prognostication.

Methods

Patients with TB and interferon-gamma release assay (IGRA)-positive and IGRA-negative family contacts were evaluated to analyze changes in apoptosis-associated serum biomarkers, which included decoy receptor 3 (DcR3), prostaglandin 2 (PGE2), and lipoxin. The prognostic implications of these serum biomarkers were also analyzed.

Results

One hundred TB patients and 92 IGRA-negative and 91 IGRA-positive family contacts were recruited. The DcR3 and PGE2 levels decreased from the IGRA-negative group to the IGRA-positive group, and peaked in the TB group. Lipoxin decreased to trough in the TB group. The three apoptosis serum markers and age were independent factors discriminating active TB from latent TB infection. In active TB, older age, co-morbidity, and higher serum DcR3 and monocyte chemotactic protein (MCP)-1 were independently associated with poorer six-month survival.

Conclusion

Apoptosis-associated serum biomarkers change along with the status of Mycobacterium tuberculosis infection. In close contacts with positive IGRA, high DcR3 and PGE2 and low lipoxin may increase the probability of active TB. Older age, co-morbidity, and high DcR3 and MCP-1 levels might be important prognostic factors that warrant further investigation.

Inflammatory macrophages in dengue virus infection pyroptosis, infectivity, and enhancement of endothelial permeability (67.5)

Macrophages (Mϕ) are the major source of inflammatory cytokines during dengue virus (DV) infection It has been shown that macrophage differentiation under macrophage-colony stimulating factor (M-CSF) (denoted as M-Macrophage) is regarded as M2-like Mϕ, while GM-CSF-derived macrophage (denoted as GM-Mϕ) is regarded as M1-like Mϕ, or inflammatory macrophages. Compared to M-Mϕ, we found that GM-Mϕ is more susceptible to DV infection, and release higher amounts of proinflammatory cytokines and infectious viral particles when incubated with DV alone or DV-Ab immune complex. In addition, GM-Mϕ releases higher amounts of IL-1and IL-18 and is susceptible to DV-induced pyropsis. Moreover, culture supernatant from DV-infected GM-Mϕ causes more severe endothelial cell permeability change than that of M-Mϕ. It is interesting to note the differential expression of innate immunity receptors, including C-type lectin CLEC5A, were found between GM-Mϕ and M-Mϕ, and anti-CLEC5A mAb is able to inhibit the release of IL-1 and IL-18, capase I activation, and pyropsis in DV-infected GM-Mϕ and M-Mϕ.

CLEC5A regulates Japanese encephalitis virus-induced neuroinflammation and lethality

CLEC5A/MDL-1, a member of the myeloid C-type lectin family expressed on macrophages and neutrophils, is critical for dengue virus (DV)-induced hemorrhagic fever and shock syndrome in Stat1^−/− mice and ConA-treated wild type mice. However, whether CLEC5A is involved in the pathogenesis of viral encephalitis has not yet been investigated. To investigate the role of CLEC5A to regulate JEV-induced neuroinflammation, antagonistic anti-CLEC5A mAb and CLEC5A-deficient mice were generated. We find that Japanese encephalitis virus (JEV) directly interacts with CLEC5A and induces DAP12 phosphorylation in macrophages. In addition, JEV activates macrophages to secrete proinflammatory cytokines and chemokines, which are dramatically reduced in JEV-infected Clec5a^−/− macrophages. Although blockade of CLEC5A cannot inhibit JEV infection of neurons and astrocytes, anti-CLEC5A mAb inhibits JEV-induced proinflammatory cytokine release from microglia and prevents bystander damage to neuronal cells. Moreover, JEV causes blood-brain barrier (BBB) disintegrity and lethality in STAT1-deficient (Stat1^−/−) mice, whereas peripheral administration of anti-CLEC5A mAb reduces infiltration of virus-harboring leukocytes into the central nervous system (CNS), restores BBB integrity, attenuates neuroinflammation, and protects mice from JEV-induced lethality. Moreover, all surviving mice develop protective humoral and cellular immunity against JEV infection. These observations demonstrate the critical role of CLEC5A in the pathogenesis of Japanese encephalitis, and identify CLEC5A as a target for the development of new treatments to reduce virus-induced brain damage.

Japanese encephalitis (JE) is one of the most common forms of viral encephalitis worldwide, and the common complication post viral encephalitis is permanent neuropsychiatric sequelae resulting from severe neuroinflammation. However, specific treatment to inhibit JEV-induced neuroinflammation is not available. We found that JEV interacts directly with CLEC5A, a C-type lectin expressed on the myeloid cell surface. This observation led to two major findings; first, we demonstrate that JEV activates macrophages and microglia via CLEC5A, and blockade of CLEC5A reduces bystander neuronal damage and JEV-induced proinflammatory cytokine secretion from macrophages and microglia. Second, peripheral administration of anti-CLEC5A mAb does not only inhibit JEV-induced BBB permeability, but also reduces the numbers of activated microglia and cell infiltration into the CNS. The attenuation of neuronal damage and reduced viral load correlate with the suppression of inflammatory cytokines TNF-α, IL-6, IL-18, and MCP-1 in the CNS. Our studies provide new insights into the molecular mechanism of neuroinflammation, and reveal a possible strategy to control neuroinflammation during viral encephalitis.

Decoy receptor 3 enhances tumor progression via induction of tumor-associated macrophages

Tumor-associated macrophages (TAMs) are the major component of tumor-infiltrating leukocytes. TAMs are heterogeneous, with distinct phenotypes influenced by the microenvironment surrounding tumor tissues. Decoy receptor 3 (DcR3), a member of the TNFR superfamily, is overexpressed in tumor cells and is capable of modulating host immunity as either a neutralizing decoy receptor or an effector molecule. Upregulation of DcR3 has been observed to correlate with a poor prognosis in various cancers. However, the mechanisms underlying the DcR3-mediated tumor-promoting effect remain unclear. We previously demonstrated that DcR3 modulates macrophage activation toward an M2-like phenotype in vitro and that DcR3 downregulates MHC class II expression in TAMs via epigenetic control. To investigate whether DcR3 promotes tumor growth, CT26-DcR3 stable transfectants were established. Compared with the vector control clone, DcR3-transfectants grew faster and resulted in TAM infiltration. We further generated CD68 promoter-driven DcR3 transgenic (Tg) mice to investigate tumor growth in vivo. Compared with wild-type mice, macrophages isolated from DcR3-Tg mice displayed higher levels of IL-10, IL-1ra, Ym1, and arginase activity, whereas the expression of IL-12, TNF-α, IL-6, NO, and MHC class II was downregulated. Significantly enhanced tumor growth and spreading were observed in DcR3-Tg mice, and the enhanced tumor growth was abolished by arginase inhibitor N-ω-hydroxy-l-norarginine and histone deacetylase inhibitor sodium valproate. These results indicated that induction of TAMs is an important mechanism for DcR3-mediated tumor progression. Our findings also suggest that targeting DcR3 might help in the development of novel treatment strategies for tumors with high DcR3 expression.

Inhibitory Effects of Ethyl Acetate Extract of Andrographis paniculata on NF-κB Trans-Activation Activity and LPS-Induced Acute Inflammation in Mice

This study was to investigate anti-inflammatory effect of Andrographis paniculata (Burm. f.) Nees (Acanthaceae) (AP). The effects of ethyl acetate (EtOAc) extract from AP on the level of inflammatory mediators were examined first using nuclear factor kappa B (NF-κB) driven luciferase assay. The results showed that AP significantly inhibited NF-κB luciferase activity and tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), macrophage inflammatory protein-2 (MIP-2) and nitric oxide (NO) secretions from lipopolysaccharide (LPS)/interferon-γ stimulated Raw264.7 cells. To further evaluate the anti-inflammatory effects of AP in vivo, BALB/c mice were tube-fed with 0.78 (AP1), 1.56 (AP2), 3.12 (AP3) and 6.25 (AP4) mg kg⁻¹ body weight (BW)/day in soybean oil, while the control and PDTC (pyrrolidine dithiocarbamate, an anti-inflammatory agent) groups were tube-fed with soybean oil only. After 1 week of tube-feeding, the PDTC group was injected with 50 mg kg⁻¹ BW PDTC and 1 h later, all of the mice were injected with 15 mg kg⁻¹ BW LPS. The results showed that the AP1, AP2, AP3 and PDTC groups, but not AP4, had significantly higher survival rate than the control group. Thus, the control, AP1, AP2, AP3 and PDTC groups were repeated for in vivo parameters. The results showed that the AP and PDTC groups had significantly lower TNF-α, IL-12p40, MIP-2 or NO in serum or peritoneal macrophages and infiltration of inflammatory cells into the lung of mice. The AP1 group also had significantly lower MIP-2 mRNA expression in brain. This study suggests that AP can inhibit the production of inflammatory mediators and alleviate acute hazards at its optimal dosages.

Decoy receptor 3: a pleiotropic immunomodulator and biomarker for inflammatory diseases, autoimmune diseases and cancer

Recently, several decoy molecules belonging to tumor necrosis factor receptor superfamily (TNFRSF) have been identified, including decoy receptor 1 (DcR1), decoy receptor 2 (DcR2), and decoy receptor 3 (DcR3). One of the tumor necrosis factor superfamily (TNFSF) members, TNF-related apoptosis-inducing ligand (TRAIL), binds to DcR1 and DcR2, which are membranous receptors with a truncated cytoplasmic domain, thus unable to transduce TRAIL-mediated signaling. In contrast to DcR1 and DcR2, DcR3 is a soluble receptor capable of neutralizing the biological effects of three other TNFSF members: Fas ligand (FasL/TNFSF6/CD95L), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A/TNFSF15). Since FasL is a potent apoptosis- and inflammation-inducing factor, LIGHT is involved in apoptosis and inflammation, and TL1A is a T cell costimulator and is involved in gut inflammation, DcR3 can be defined as an immunomodulator on the basis of its neutralizing effects on FasL, LIGHT, and TL1A. Initial studies demonstrated that DcR3 expression is elevated in tumors cells; however, later work showed that DcR3 expression is also upregulated in inflammatory diseases, where serum DcR3 levels correlate with disease progression. In addition to its neutralizing effect, DcR3 also acts as an effector molecule to modulate cell function via 'non-decoy' activities. This review focuses on the immunomodulatory effects of DcR3 via 'decoy' and 'non-decoy' functions, and discusses the potential of DcR3 as a biomarker to predict cancer invasion and inflammation progression. We also discuss the possible utility of recombinant DcR3 as a therapeutic agent to control autoimmune diseases, as well as the potential to attenuate tumor progression by inhibiting DcR3 expression.

Survey of immune-related, mannose/fucose-binding C-type lectin receptors reveals widely divergent sugar-binding specificities

C-type lectins (CTLs) are proteins that contain one or more carbohydrate-recognition domains (CRDs) that require calcium for sugar binding and share high degree of sequence homology and tertiary structure. CTLs whose CRD contain EPN (Glu-Pro-Asn) tripeptide motifs have potential to bind mannose (Man), N-acetylglucosamine (GlcNAc), glucose (Glc) and l-fucose (Fuc), whereas those with QPD (Glu-Pro-Asp) tripeptide motifs bind galactose (Gal) and N-acetylgalactosamine (GalNAc). We report here for the first time a direct comparison of monosaccharide (and some di- and trisaccharides)-binding characteristics of 11 EPX-containing (X = N, S or D) immune-related CTLs using a competition assay and an enzyme-linked immunosorbent assay, and neoglycoproteins as ligand. The EPX CTLs studied are DC-SIGN, L-SIGN, mSIGNR1, human and mouse mannose receptors, Langerin, BDCA-2, DCIR, dectin-2, MCL and MINCLE. We found that: (1) they all bound Man and Fuc; (2) binding of Glc and GlcNAc varied considerably among these lectins, but was always less than Man and Fuc; (3) in general, Gal and GalNAc were not bound. However, dectin-2, DCIR and MINCLE showed ability to bind Gal/GalNAc; (4) DC-SIGN, L-SIGN, mSIGNR1 and Langerin showed enhanced binding of Manα2Man over Man, whereas all others showed no enhancement; (5) DC-SIGN bound Le(x) trisaccharide structure, which has terminal Gal and Fuc residues, more avidly than Fuc, whereas L-SIGN, mSIGNR1, DCIR and MINCLE bound Le(x) less avidly than Fuc. BDCA-2, dectin-2, Langerin, MCL and mannose receptor did not bind Le(x) at all.

Green fabrication of agar-conjugated Fe3O4 magnetic nanoparticles

Magnetic nanoparticles are of great interest both for fundamental research and emerging applications. In the biomedical field, magnetite (Fe(3)O(4)) has shown promise as a hyperthermia-based tumor therapeutic. However, preparing suitable solubilized magnetite nanoparticles is challenging, primarily due to aggregation and poor biocompatibility. Thus methods for coating Fe(3)O(4) NPs with biocompatible stabilizers are required. We report a new method for preparing Fe(3)O(4) nanoparticles by co-precipitation within the pores of agar gel samples. Permeated agar gels were then dried and ground into a powder, yielding agar-conjugated Fe(3)O(4) nanoparticles. Samples were characterized using XRD, FTIR, TGA, TEM and SQUID. This method for preparing agar-coated Fe(3)O(4) nanoparticles is environmentally friendly, inexpensive and scalable.

Vaccination targeting surface FomA of Fusobacterium nucleatum against bacterial co-aggregation: Implication for treatment of periodontal infection and halitosis

The mechanical therapy with multiple doses of antibiotics is one of modalities for treatment of periodontal diseases. However, treatments using multiple doses of antibiotics carry risks of generating resistant strains and misbalancing the resident body flora. We present an approach via immunization targeting an outer membrane protein FomA of Fusobacterium nucleatum (F. nucleatum), a central bridging organism in the architecture of oral biofilms. Neutralization of FomA considerably abrogated the enhancement of bacterial co-aggregation, biofilms and production of volatile sulfur compounds mediated by an inter-species interaction of F. nucleatum with Porphyromonas gingivalis (P. gingivalis). Vaccination targeting FomA also conferred a protective effect against co-infection-induced gum inflammation. Here, we advance a novel infectious mechanism by which F. nucleatum co-opts P. gingivalis to exacerbate gum infections. FomA is highlighted as a potential target for development of new therapeutics against periodontal infection and halitosis in humans.

Profiling carbohydrate-receptor interaction with recombinant innate immunity receptor-Fc fusion proteins

The recognition of bacteria, viruses, fungi, and other microbes is controlled by host immune cells, which are equipped with many innate immunity receptors, such as Toll-like receptors, C-type lectin receptors, and immunoglobulin-like receptors. Our studies indicate that the immune modulating properties of many herbal drugs, for instance, the medicinal fungus Reishi (Ganoderma lucidum) and Cordyceps sinensis, could be attributed to their polysaccharide components. These polysaccharides specifically interact with and activate surface receptors involved in innate immunity. However, due to the complexity of polysaccharides and their various sources from medicinal fungi, quantitative analysis of medicinal polysaccharide extracts with regard to their functions represents a major challenge. To profile carbohydrate-immune receptor interactions, the extracellular domains of 17 receptors were cloned as Fc-fusion proteins, such that their interactions with immobilized polysaccharides could be probed in an enzyme-linked immunosorbent assay. The results show that several innate immune receptors, including Dectin-1, DC-SIGN, Langerin, Kupffer cell receptor, macrophage mannose receptor, TLR2, and TLR4, interact with the polysaccharide extracts from G. lucidum (GLPS). This analysis revealed distinct polysaccharide profiles from different sources of medicinal fungi, and the innate immune receptor-based enzyme-linked immunosorbent assay described here can serve as a high-throughput profiling method for the characterization and quality control of medicinal polysaccharides. It also provides a means to dissect the molecular mechanism of medicinal polysaccharide-induced immunomodulation events.

Decoy receptor 3 levels in peripheral blood predict outcomes of acute respiratory distress syndrome

RATIONALE

Acute respiratory distress syndrome (ARDS), a serious inflammatory reaction to acute lung injury, is associated with high mortality rates. Decoy receptor (DcR) 3 is a soluble protein with immunomodulatory effects. Biomarkers that reliably predict outcomes in ARDS are not currently available.

OBJECTIVES

Comparing DcR3 with the Acute Physiology and Chronic Health Evaluation (APACHE) II scores and three other plasma markers to explore the association of DcR3 and the clinical outcome in ARDS.

METHODS

Eighty-eight patients with ARDS were studied. Baseline APACHE II scores and clinical data were recorded. Plasma levels of DcR3, soluble triggering receptor expressed on myeloid cells (sTREM)-1, tumor necrosis factor (TNF)-alpha, and IL-6 were measured on Day 1 and later time points, and correlated with the survival status on Day 28 after the onset of ARDS. For validation, 59 patients with ARDS from another medical center were studied.

MEASUREMENTS AND MAIN RESULTS

Among the biomarkers evaluated, only DcR3 discriminated the survivors and nonsurvivors at all time points in the first week of ARDS. DcR3 independently associated with and best predicted the 28-day mortality of patients with ARDS. Plasma DcR3 levels most correlated to multiple-organ dysfunction and ventilator dependence. Compared with survivors, the nonsurvivors had higher DcR3 levels regardless of the APACHE II scores. Kaplan-Meier survival analysis showed higher mortality in patients with ARDS with higher DcR3 levels. The outcome prediction of patients with ARDS by plasma DcR3 levels was recapitulated by the validation cohort.

CONCLUSIONS

High plasma DcR3 levels correlate with development of multiple-organ dysfunction and independently predict the 28-day mortality in patients with ARDS.

Galectin-1 promotes immunoglobulin production during plasma cell differentiation

Galectin-1, a beta-galactoside-binding soluble lectin, has been implicated in regulating immune system homeostasis. We investigated the function of galectin-1 in plasma cell differentiation and found that it is induced in primary murine and human differentiating B cells. B lymphocyte-induced maturation protein-1 (Blimp-1), a master regulator for plasma cell differentiation, was necessary and sufficient to induce galectin-1 expression. Notably, ectopic expression of galectin-1 in mature B cells increased Ig mu-chain transcript levels as well as the overall level of Ig production. This function of galectin-1 was dependent on binding to cell surface glycosylated counter receptors, as a galectin-1 mutant deficient in beta-galactoside binding showed diminished ability to promote Ig production. Extracellular galectin-1 bound more significantly to mature B cells than to plasma cells. Lastly, we found that the sugar compound N-acetyllactosamine blocked the binding of galectin-1 to murine splenic B cells and inhibited their differentiation. Taken together, these data are the first to demonstrate a role for galectin-1 in promoting Ig production during plasma cell differentiation.

Expression of a soluble decoy receptor 3 in patients with diffuse large B-cell lymphoma predicts clinical outcome

The soluble decoy receptor 3 (DcR3) is a member of the TNF receptor superfamily. It is regarded as a decoy receptor released from tumor cells to escape host immune response by neutralizing the cytotoxic and immunomodulatory effects of FasL, LIGHT and TL1A. Overexpression of DcR3 has been observed in several human malignancies; however, only limited information exists on the role of DcR3 in non-Hodgkin lymphoma especially for B-cell origin. In the current study, the expression profile of DcR3 was analyzed by RT-PCR and immunohistochemistry (IHC) in a set of lymphoma cell lines including T-cell and B-cell lymphomas. The result demonstrated that overexpression of DcR3 was detected in most T-cell lymphoma cells, which was consistent with previous reports. Interestingly, overexpression of DcR3 was also detected both in the B-cell lymphoma cell lines and diffuse large B cell lymphoma (DLBCL) patients. DcR3 overexpression was associated with a worse prognosis in DLBCL patients (p=0.05). An in vitro study showed that neutralization of DcR3 increased the percentage of doxorubicin-mediated apoptosis in two B-cell lymphoma cell lines, which indicated the possibility of DcR3 mediated chemo-resistance in B-cell lymphomas. We suggest that overexpression of DcR3 is associated with a worse prognosis in DLBCL and the possible mechanism may act through the increase of chemo-resistance of lymphoma cells.

CLEC5A is critical for dengue-virus-induced lethal disease

Dengue haemorrhagic fever and dengue shock syndrome, the most severe responses to dengue virus (DV) infection, are characterized by plasma leakage (due to increased vascular permeability) and low platelet counts. CLEC5A (C-type lectin domain family 5, member A; also known as myeloid DAP12-associating lectin (MDL-1)) contains a C-type lectin-like fold similar to the natural-killer T-cell C-type lectin domains and associates with a 12-kDa DNAX-activating protein (DAP12) on myeloid cells. Here we show that CLEC5A interacts with the dengue virion directly and thereby brings about DAP12 phosphorylation. The CLEC5A-DV interaction does not result in viral entry but stimulates the release of proinflammatory cytokines. Blockade of CLEC5A-DV interaction suppresses the secretion of proinflammatory cytokines without affecting the release of interferon-alpha, supporting the notion that CLEC5A acts as a signalling receptor for proinflammatory cytokine release. Moreover, anti-CLEC5A monoclonal antibodies inhibit DV-induced plasma leakage, as well as subcutaneous and vital-organ haemorrhaging, and reduce the mortality of DV infection by about 50% in STAT1-deficient mice. Our observation that blockade of CLEC5A-mediated signalling attenuates the production of proinflammatory cytokines by macrophages infected with DV (either alone or complexed with an enhancing antibody) offers a promising strategy for alleviating tissue damage and increasing the survival of patients suffering from dengue haemorrhagic fever and dengue shock syndrome, and possibly even other virus-induced inflammatory diseases.

Decoy receptor 3 ameliorates an autoimmune crescentic glomerulonephritis model in mice

Autoimmune crescentic glomerulonephritis (ACGN) is a variant of crescentic glomerulonephritis. The outcome of treatment of crescentic glomerulonephritis is poor. Binding of decoy receptor 3 (DCR3) to its ligand is capable of downregulating the alloresponsiveness of T cells. DCR3 has also been shown to benefit an experimental autoimmune model of diabetes. This study tested the hypothesis that a potential immune regulator, DCR3, could prevent the evolution of ACGN. With the use of an established ACGN model in mice, mice were treated with 100 microg/10 g body wt human DCR3 by hydrodynamics-based gene delivery at 14-d intervals. The results showed that the gene therapy resulted in (1) suppression of T and B cell activation and T cell proliferation; (2) a reduction in serum levels of proinflammatory cytokines; (3) improvement of proteinuria and renal dysfunction; (4) prevention of glomerular crescent formation, renal interstitial inflammation, and glomerulosclerosis; (5) a reduction in serum levels of autoantibodies and glomerular immune deposits; (6) inhibition of apoptosis in the spleen and kidney; (7) prevention of T cell and macrophage infiltration of the kidney; and (8) suppression of fibrosis-related gene expression in the kidney compared with empty vector-treated (disease control) ACGN mice. On the basis of these findings, it is proposed that human DCR3 exerts its preventive and protective effects on ACGN through modulation of T cell activation/proliferation, B cell activation, protection against apoptosis, and suppression of mononuclear leukocyte infiltration in the kidney.

Effect of a selective nonsteroidal anti-inflammatory drug, celecoxib, on the reproductive function of female mice

BACKGROUND

The aim of the present study was to determine if long-term use of a cyclooxygenase-2 (COX-2) inhibitor affects fertility or ovulation in female mice.

METHODS

Twenty-four female mice, 25 days of age, were given a selective COX-2 inhibitor: 3 mg/kg celecoxib (n = 8), 5 mg/kg celecoxib (n = 8),or placebo (n = 8) in a random fashion. Eight female mice, 10-11 weeks old, given 3 mg/kg celecoxib (n = 4) or placebo (n = 4) were subjected to continuous mating studies.

RESULTS

Results from the 24 mice (n = 8 for each group) showed that oocyte number was not significantly different between female mice treated with either 3 mg/kg or 5 mg/kg celecoxib and placebo (21.4 +/- 2.5, 21.5 +/- 3.3, 23.3 +/- 3.8, respectively). From the continuous mating study, the litter size of female mice treated with celecoxib was not significantly different (8.2 +/- 1.3 pups/litter) compared to those treated with placebo (8.3 +/- 1.2 pups/litter). In addition, female mice treated with celecoxib had an average of 2.8 +/- 0.5 litters in a 12-week period, which was similar to female mice treated with placebo (3.0 +/- 0.8 litters/female).

CONCLUSION

This study suggests that use of low-dose (<or= 5 mg/kg) selective COX-2 inhibitor in a mouse model does not significantly impair the female reproductive function.

Epstein-Barr virus transcription activator Rta upregulates decoy receptor 3 expression by binding to its promoter

Decoy receptor 3 (DcR3) is a soluble decoy receptor belonging to the tumor necrosis factor receptor superfamily that is overexpressed in various malignant tumor types. DcR3 has been implicated in tumor cell survival by inhibiting apoptosis and by interfering with immune surveillance. A previous study showed that DcR3 expression is associated with Epstein-Barr virus (EBV)-positive lymphomas but rarely with non-EBV-positive B-cell lymphomas, suggesting that the presence of EBV may affect DcR3 expression. Here, we demonstrated enhanced DcR3 expression upon EBV reactivation in P3HR1 cells and in EBV-infected 293 cells. This enhancement, however, could not be detected in 293 cells infected with EBV with BRLF1 deleted. We found that EBV transactivator, Rta, could upregulate DcR3 expression by direct binding to an Rta-responsive element (RRE) located in the DcR3 promoter region and that this RRE is important for Rta-mediated DcR3 expression. Overexpressing CREB-binding protein (CBP) further enhanced Rta-dependent DcR3 expression, suggesting Rta-dependent DcR3 transcription activity is mediated by CBP. Previously, Rta was shown to enhance phosphatidylinositol-3 kinase (PI3-K) activity. However, Rta-transduced PI 3-K activity plays a minor role in DcR3 expression. This is the first report to demonstrate that Rta upregulates a cellular gene by direct binding to an RRE.

Signaling pathways of LIGHT induced macrophage migration and vascular smooth muscle cell proliferation

The biological actions of LIGHT, a member of the tumor necrosis factor superfamily, are mediated by the interaction with lymphotoxin-beta receptor (LTbetaR) and/or herpes virus entry mediator (HVEM). Previous study demonstrated high-level expressions of LIGHT and HVEM receptors in atherosclerotic plaques. To investigate the role of LIGHT in the functioning of macrophages and vascular smooth muscle cells (VSMC) in relation to atherogenesis, we determined the effects of LIGHT on macrophage migration and VSMC proliferation. We found LIGHT through HVEM activation can induce both events. LIGHT-induced macrophage migration was associated with activation of signaling kinases, including MAPKs, PI3K/Akt, NF-kappaB, Src members, and FAK. Proliferation of VSMC was also shown relating to the activation of MAPKs, PI3K/Akt, and NF-kappaB, which consequently led to alter the expression of cell cycle regulatory molecules. Down-regulation of p21, p27, and p53, and inversely up-regulation of cyclin D and RB hyper-phosphorylation were demonstrated. In conclusion, LIGHT acts as a novel mediator for macrophage migration and VSMC proliferation, suggesting its involvement in the atherogenesis.

Molecular cloning and gene expression of the gonadotropin-releasing hormone receptor in the orange-spotted grouper, Epinephelus coioides

The objective of this study was to investigate the molecular mechanisms of gonadotropin-releasing hormone receptor (GnRH-R) involved in the endocrine regulation of reproduction in the orange-spotted grouper, Epinephelus coioides. The full-length cDNA encoding GnRH-R type I was successfully cloned from the pituitary by reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods in the grouper. The complete GnRH-R type I cDNA is 1607 bp, which includes an open reading frame of 1092 bp encoding a protein of 364 amino acids, a seven-alpha helix transmembrane domain, a N-terminal extracellular domain, and a C-terminal cytoplasmic domain. The expression of GnRH-R type I was found to be highest in the pituitary. An intramuscular injection of various GnRH types in vivo was attempted. The expression of GnRH-R type I was stimulated by a single injection of salmon GnRH, while in the case of chicken GnRH II treatment, the expression of GnRH-R type I was inhibited. This suggests that the action of chick GnRH II is probably enhanced through the GnRH receptor of different forms. Furthermore, none of them were expressed by an injection of seabream GnRH, and this is likely attributed to the injection dose being below the threshold level, and this remains to be further examined. In conclusion, GnRHs of various types are effective in stimulating the expression of gonadotropins through various forms of the GnRH-R, and multiple forms of the receptor gene likely exist in teleosts.

Intracellular delivery can be achieved by bombarding cells or tissues with accelerated molecules or bacteria without the need for carrier particles

To deliver non-permeable molecules into cells, one can utilize protocols such as microinjection, electroporation, liposome-mediated transfection or virus-mediated transfection. However, each method has its own limitations. Here we have developed a new molecular delivery technique where live cells or tissues are bombarded with highly accelerated molecules directly and without the need to conjugate the molecules onto carrier particles, which is essential in conventional "gene gun" experiments. Gene bombardments can be applied to well-differentiated cells, primary cultured cells/neurons or tissue explants, all of which are notoriously difficult to transfect. Exogenously made proteins and even bacteria can be effectively introduced into cells where they can execute their function or replicate. Our experimental results and physical model support the notion that accelerated chemicals, proteins, or microorganisms carry enough momentum to penetrate the plasma membrane. The bombardment process is associated with a transient (approximately 10 min) increase in cell permeability, but such membrane leakage has a minimal adverse effect on cell survival.

Attenuation of bone mass and increase of osteoclast formation in decoy receptor 3 transgenic mice

Decoy receptor 3 (DcR3), a soluble receptor for FasL, LIGHT, and TL1A, induces osteoclast formation from monocyte, macrophage, and bone stromal marrow cells. However, the function of DcR3 on bone formation remains largely unknown. To understand the function of DcR3 in bone formation in vivo, transgenic mice overexpressing DcR3 were generated. Bone mineral density (BMD) and bone mineral content (BMC) of total body were significantly lower in DcR3 transgenic mice as compared with wild-type controls. The difference in BMD and BMC between DcR3 transgenic and control mice was confirmed by histomorphometric analysis, which showed a 35.7% decrease in trabecular bone volume in DcR3 transgenic mice in comparison with wild-type controls. The number of osteoclasts increased in DcR3 transgenic mice. In addition, local administration of DcR3 (30 microg/ml, 10 microl, once/day) into the metaphysis of the tibia via the implantation of a needle cannula significantly decreased the BMD, BMC, and bone volume of secondary spongiosa in tibia. Local injection of DcR3 also increased osteoclast numbers around trabecular bone in tibia. Furthermore, coadminstration of soluble tumor necrosis factor receptor inhibitor/Fc chimera (TNFRSF1A) but not osteoprotegerin inhibited the action of DcR3. In addition, in an assay of osteoclast activity on substrate plates, DcR3 significantly increased the resorption activity of mature osteoclasts. Treatment with higher concentrations of DcR3 slightly increased nodule formation and alkaline phosphatase activity of primary cultured osteoblasts. These results indicate that DcR3 may play an important role in osteoporosis or other bone diseases.

Kinetic Th1/Th2 responses of transgenic mice with bacterial meningitis induced by Haemophilus influenzae

To investigate the kinetic Th1/Th2 immunopathogenic mechanisms of Haemophilus influenzae meningitis, we established a murine experimental model of meningitis and elucidated the Th1/Th2 immune responses in T1/T2 doubly transgenic mice based on a BALB/c background under the control of the IFN-gamma (interferon-gamma)/IL-4 (interleukin-4) promoters respectively. NTHi (non-typeable Haemophilus influenzae) meningitis was induced in these mice by inoculation with either a colonized (CNTHi) or invasive (INTHi) strain of NTHi. Mice inoculated with CNTHi displayed a less severe degree of disease in terms of clinical symptoms, mortality rate and brain histopathology. Conversely, INTHi-inoculated mice had more severe clinical symptoms. CNTHi-inoculated mice had a more significant Th1 response in terms of a higher percentage and longer maintenance of Th1 cells, and more production of IFN-gamma from strain-specific antigen-stimulated splenocytes than INTHi-inoculated mice. In contrast, INTHi-inoculated mice had a more significant Th2 response. This was due to a significant increase in IL-4-producing CD4(+) T-cells (Th2 cells) and more production of IL-4 from strain-specific antigen-stimulated splenocytes accompanied by a rapid decline of Th1 cells in INTHi-inoculated mice. In conclusion, the preferential Th1/Th2 trend in this murine model of NTHi meningitis is correlated with clinical severity as well as isolated characteristics of the pathogens themselves.

Preparation and characterization of monoclonal antibody against protein TREM-like transcript-1 (TLT-1)

TREM-like transcript-1 (TLT-1) was initially characterized as the putative inhibitory receptor within the TREM locus on chromosome 6 and was suggested to play a critical role in modulating TREM-associated immunity. Recently, TLT-1 was found not to function as an inhibiting member of the TREM family; however, it may play a significant role in maintaining vascular hemostasis, coagulation, and inflammation at sites of injury through its location in platelets. In this study, we have successfully generated a monoclonal antibody that can be applied to assays, including enzyme-linked immunosorbent assay (ELISA), Western immunoblotting, immunofluorescence, and Fluorescence-Activated Cell Sorter (Becton-Dickinson) (FACS), for the study of TLT-1 functions in physiological and pathological conditions.

Inhibition of Lymphotoxin-β Receptor–Mediated Cell Death by Survivin-ΔEx3

TNFSF14/LIGHT is a member of the tumor necrosis factor superfamily that binds to lymphotoxin-beta receptor (LTbetaR) to induce cell death via caspase-dependent and caspase-independent pathways. It has been shown that cellular inhibitor of apoptosis protein-1 inhibits cell death by binding to LTbetaR-TRAF2/TRAF3 complexes and caspases. In this study, we found that both Kaposi's sarcoma-associated herpesvirus K7 (KSHV-K7), a viral inhibitor of apoptosis protein, and the structurally related protein survivin-DeltaEx3 could inhibit LTbetaR-mediated caspase-3 activation. However, only survivin-DeltaEx3 could protect cells from LTbetaR-mediated cell death. The differential protective effects of survivin-DeltaEx3 and KSHV-K7 can be attributed to the fact that survivin-DeltaEx3, but not KSHV-K7, is able to maintain mitochondrial membrane potential and inhibit second mitochondria-derived activator of caspase/DIABLO release. Moreover, survivin-DeltaEx3 is able to inhibit production of reactive oxygen species and can translocate from nucleus to cytosol to associate with apoptosis signal-regulating kinase 1 after activation of LTbetaR. Furthermore, survivin-DeltaEx3 protects LTbetaR-mediated cell death in caspase-3-deficient MCF-7 cells. Thus, survivin-DeltaEx3 is able to regulate both caspase-dependent and caspase-independent pathways, whereas inhibition of caspase-independent pathway is both sufficient and necessary for its protective effect on LTbetaR-mediated cell death.

The glycosaminoglycan-binding domain of decoy receptor 3 is essential for induction of monocyte adhesion

Decoy receptor 3 (DcR3), a soluble receptor for Fas ligand, LIGHT (homologous to lymphotoxins shows inducible expression and competes with HSV glycoprotein D for herpes virus entry mediator, a receptor expressed by T lymphocytes), and TNF-like molecule 1A, is highly expressed in cancer cells and in tissues affected by autoimmune disease. DcR3.Fc has been shown to stimulate cell adhesion and to modulate cell activation and differentiation by triggering multiple signaling cascades that are independent of its three known ligands. In this study we found that DcR3.Fc-induced cell adhesion was inhibited by heparin and heparan sulfate, and that DcR3.Fc was unable to bind Chinese hamster ovary K1 mutants defective in glycosaminoglycan (GAG) synthesis. Furthermore, the negatively charged, sulfated GAGs of cell surface proteoglycans, but not their core proteins, were identified as the binding sites for DcR3.Fc. A potential GAG-binding site was found in the C-terminal region of DcR3, and the mutation of three basic residues, i.e., K256, R258, and R259, to alanines abolished its ability to trigger cell adhesion. Moreover, a fusion protein comprising the GAG-binding region of DcR3 with an Fc fragment (DcR3_HBD.Fc) has the same effect as DcR3.Fc in activating protein kinase C and inducing cell adhesion. Compared with wild-type THP-1 cells, cell adhesion induced by DcR3.Fc was significantly reduced in both CD44v3 and syndecan-2 knockdown THP-1 cells. Therefore, we propose a model in which DcR3.Fc may bind to and cross-link proteoglycans to induce monocyte adhesion.

Immunological characterizations of the nucleocapsid protein based SARS vaccine candidates

The recombinant nucleocapsid (rN) protein of the coronavirus (CoV) responsible for severe acute respiratory syndrome (SARS) was cloned and expressed in Escherichia coli, extracted from cell lysates containing 6M urea, then purified by Ni(2+)-affinity chromatography. In animal immunogenicity studies, we found that most anti-rN protein antibodies were IgG2a in BALB/c mice vaccinated with rN emulsified in Montanide ISA-51 containing the synthetic oligodeoxynucleotide, CpG. In contrast, anti-rN protein antibodies of mice immunized with rN protein in PBS were found to mainly be IgG1. These results indicated that ISA-51/CpG-formulated rN protein was dramatically biased toward a Th1 immune response. To identify the B-cell immunodominant epitopes of the rN protein in the mouse and monkey, the reactivities of antisera raised against purified rN proteins formulated in ISA-51/CpG were tested with a panel of overlapping synthetic peptides covering the entire N protein sequence. Three immunodominant linear B-cell epitope regions were mapped to residues 166-180, 356-375, and 396-410 of the rN protein. When the reactivities of these peptides were screened with human sera from five SARS patients, peptides corresponding to residues 156-175 reacted strongly with sera from two of the SARS patients. These results indicated that the region around residues 156-175 of the N protein is immunogenic in the mouse, monkey, and human. We found that peptides corresponding to residues 1-30, 86-100, 306-320, and 351-365 contained murine immunodominant T-cell epitopes. To identify functional CTL epitopes of the N protein, BALB/c mice were immunized with peptides containing the H-2K(d) CTL motif emulsified in adjuvant ISA-51/CpG. Using an IFN-gamma secretion cell assay and analysis by flow cytometry, peptides containing residues 81-95 were found to be capable of stimulating both CD4(+) and CD8(+) cell proliferation in vitro. We also only observed that peptides corresponding to residues 336-350 were capable of stimulating IFN-gamma production in T-cell cultures derived from peripheral blood mononuclear cells (PBMCs) of macaques immunized with the rN protein emulsified in ISA/CpG adjuvant. Our current results together with those of others suggest that some immunodominant B-cell and T-cell epitopes are conserved in the mouse, monkey, and human. This information is very important for the development SARS diagnostic kits and a vaccine.

Involvement of norepinephrine in the hyperglycemic responses of the freshwater giant prawn, Macrobrachium rosenbergii, under cold shock

Hyperglycemic response of freshwater giant prawn, Macrobrachium rosenbergii, under acute cold shock was investigated, and the involvement and stimulatory pathways of norepinephrine (NE) on induced-glycemia were further examined. Remarkable elevations in hemolymph glucose at comparable magnitude were observed in both intact and eyestalkless prawn under cold treatments, suggesting that hyperglycemic response of this species is not solely mediated through the actions of crustacean hyperglycemic hormone released from X-organ sinus gland complex on the target tissues, but NE is involved. Positive and significant correlations were noted between the hemolymph glucose titers and NE contents in both thoracic ganglia and the hemolymph, suggesting that NE plays a significant role in the hyperglycemic responses of this species under cold. Depressive effects of various adrenoceptor antagonists monitored in vivo and in vitro further suggest that the action of NE is primarily mediated through both alpha1- and beta1-adrenoceptors.

An integrated healthcare enterprise information portal and healthcare information system framework

The paper presents an integrated, distributed Healthcare Enterprise Information Portal (HEIP) and Hospital Information Systems (HIS) framework over wireless/wired infrastructure at National Taiwan University Hospital (NTUH). A single sign-on solution for the hospital customer relationship management (CRM) in HEIP has been established. The outcomes of the newly developed Outpatient Information Systems (OIS) in HIS are discussed. The future HEIP blueprints with CRM oriented features: e-Learning, Remote Consultation and Diagnosis (RCD), as well as on-Line Vaccination Services are addressed. Finally, the integrated HEIP and HIS architectures based on the middleware technologies are proposed along with the feasible approaches. The preliminary performance of multi-media, time-based data exchanges over the wireless HEIP side is collected to evaluate the efficiency of the architecture.

Attenuation of Th1 response in decoy receptor 3 transgenic mice

The soluble decoy receptor 3 (DcR3) is a member of the TNFR superfamily. Because DcR3 is up-regulated in tumor tissues and is detectable in the sera of cancer patients, it is regarded as an immunosuppressor to down-regulate immune responses. To understand the function of DcR3 in vivo, we generated transgenic mice overexpressing DcR3 systemically. In comparison with HNT-TCR (HNT) transgenic mice, up-regulation of IL-4 and IL-10 and down-regulation of IFN-gamma, IL-12, and TNF-alpha were observed in the influenza hemagglutinin(126-138) peptide-stimulated splenocytes of HNT-DcR3 double-transgenic mice. When infected with Listeria monocytogenes, DcR3 transgenic mice show attenuated expression of IFN-gamma as well as increased susceptibility to infection. The Th2 cell-biased phenotype in DcR3 transgenic mice is attributed to decreased IL-2 secretion by T cells, resulting in the suppression of IL-2 dependent CD4(+) T cell proliferation. This suggests that DcR3 might help tumor growth by attenuating the Th1 response and suppressing cell-mediated immunity.

Kinetics of adaptive immunity to Haemophilus influenzae type b meningitis in transgenic mice: evidence from diverse expression of double T1/T2 transgenes and Th1/Th2-related cytokines

To investigate the kinetic changes in adaptive immunity during experimental Haemophilus influenzae type b (Hib) meningitis, we established a murine meningitis model based on T1/T2 doubly transgenic mice. These mice carry two transgenes that express two distinct cell-surface markers: a human Thy1 transgene (hThy1) under the control of the murine IFN-gamma promoter, and a murine Thy1.1 transgene (mThy1.1) under the control of the murine IL-4 promoter, designated T1 and T2, respectively. Mice infected with Hib displayed severest symptoms and lowest total splenocyte counts on day 3 after infection. Simultaneously, we examined the significantly low percentage of CD19+ B cells, the relatively high level of CD4+ T cells and significantly high percentage of CD8+ T cells in Hib-infected mice. Furthermore, we observed the early induction of both Th1 and Th2 responses, in terms of the augmentation of Th1 cells (IFN-gamma-producing CD4+ T cells) and Th2 cells (IL-4-producing CD4+ T cells) in Hib-infected mice. On day 7 after infection, the Th1 response gradually declined and the Th2 response rather sustained. Two weeks after infection, both Th1 and Th2 cells were barely detectable. Moreover, we demonstrated using an antigen-specific re-stimulation test to analyze the effector function of lymphocyte subsets that CD8+ T cells contributed to more predominantly production of IFN-gamma than CD4+ T cells did; and CD4+ T cells partly contributed to the secretion of IL-4 from flowcytometry of intracellular cytokine staining. Our results support that these transgenic mice provide an available model to dissect the complex kinetic change of adaptive immunity in bacterial infectious diseases.

Differential regulation of interleukin-8 gene transcription by death receptor 3 (DR3) and type I TNF receptor (TNFRI)

TL1A induces interleukin-8 (IL-8) secretion in human peripheral blood monocyte-derived macrophage in a dose- and time-dependent manner. Overexpression of its cognate receptor DR3 can induce a higher amount of IL-8 protein secretion than that induced by TNFRI even though both receptors activate IL-8 gene transcription in a similar fashion. The underlying mechanism for the regulation of the IL-8 gene transcription by DR3 has not been investigated yet. Here, we used HEK293 cells as a model system to dissect the possible signaling components that are involved in the regulation of DR3-mediated IL-8 gene expression. Although both DR3 and TNFRI activated TRAF2 and NF-kappaB to induce IL-8 gene transcription, the kinase cascades that transduce signals for DR3- and TNFRI-induced IL-8 gene transcription are different. The axis TAK1/ASK1-MKK4/MKK7-JNK2 is responsible for DR3-mediated IL-8 gene expression whereas the axis ASK1-MKK4-JNK1/JNK2/p38MAPK is the choice for TNFRI-mediated activation of IL-8 gene expression. This indicates that the downstream signaling pathways of DR3 and TNFRI for IL-8 secretion are divergent even though both receptors contain death-domain and induce IL-8 secretion via TRAF2.

Immunopathogenic role of TH1 cells in autoimmune diabetes: Evidence from a T1 and T2 doubly transgenic non-obese diabetic mouse model

To improve the feasibility of in vivo monitoring of autoreactive T cells in the diabetogenic process, we generated T1 and T2 doubly transgenic non-obese diabetic (NOD) mice in which transgenic human CD90 (hCD90) is simultaneously expressed on IFN-gamma-producing cells or murine CD90.1 (mCD90.1) is expressed on IL-4-producing cells. These transgenic NOD mice develop diabetes with the same kinetics and incidence as wild type NOD mice, permitting the physiological characterization of CD4(+)hCD90(+) cells, which represent T(H)1 cells in lymphoid organs and at the site of insulitis. CD4(+)hCD90(+) cells had a higher capacity to secret IFN-gamma than CD4(+)hCD90(-) cells in an autoantigen-specific manner. Transgenic mice treated with GAD65 plasmid were protected from autoimmune diabetes, and had a lower number of CD4(+)hCD90(+) cells, confirming the pathogenic role of CD4(+)hCD90(+) cells in autoimmune diabetes. To further investigate the effect of IL-12 on the development of T(H)1 cells in autoimmune diabetes, we crossed these doubly transgenic mice to IL-12p35-deficient NOD mice. Despite severe disturbance of diabetes in p35(-/-) mice, the frequency of T(H)1 cells in these mice was slightly lower than in wild type mice. These data support the pathological role of IL-12 in autoimmune diabetes and suggest the existence an IL-12-independent pathway of T(H)1 development.

Production of human serum albumin by sugar starvation induced promoter and rice cell culture

Human serum albumin (HSA) is the most widely used clinical serum protein. Currently, commercial HSA can only be obtained from human plasma, due to lack of commercially feasible recombinant protein expression systems. In this study, inducible expression and secretion of HSA by transformed rice suspension cell culture was established. Mature form of HSA was expressed under the control of the sucrose starvation-inducible rice alpha Amy3 promoter, and secretion of HSA into the culture medium was achieved by using the alpha Amy3 signal sequence. High concentrations of HSA were secreted into culture medium in a short time (2-4 days) by sucrose depletion after cell concentrations had reached a peak density in culture medium containing sucrose. The recombinant HSA had the same electrophoretic mobility as commercial HSA and was stable and free from apparent proteolysis in the culture medium. In a flask scale culture with repeated sucrose provision-depletion cycles, HSA was stably produced with yields up to 11.5% of total medium proteins or 15 mg/L per cycle after each sucrose provision-depletion cycle. A bubble column type bioreactor was designed for production of HSA. In the bioreactor scale culture, HSA was produced with yields up to 76.4 mg/L 4 days after sucrose depletion. HSA was purified from the culture medium to high purity by a simple purification scheme. Enrichment of HSA in culture medium simplifies downstream purification, minimizes protease degradation, and may reduce production cost. The combination of a DNA construct containing the alpha Amy3 promoter and signal sequence, and the use of a rice suspension cell culture can provide an effective system for the production of recombinant pharmaceutical proteins.

Altered mRNA expressions of sialyltransferases in ovarian cancers

OBJECTIVE

Aberrant glycosylation occurs in essentially all types of experimental and human cancers, and many glycosyl epitopes constitute tumor-associated antigens (for example, CA125). Many recent studies have indicated that some, if not all, aberrant glycosylation is a result of altered sialyltransferase (ST) expression; however, there is little known of the role of the altered mRNA expression of ST in ovarian cancers.

METHODS

Alterations in ST mRNA expression in postmenopausal ovarian tissues, including those of normal controls (n=24) and malignant serous ovarian cancers (n=24), were examined by means of real-time quantitative reverse transcription-polymerase chain reaction (RTQ-PCR). Maackia Amurensis Agglutinin type 2 (MAA) specific foralpha2,3-linked NeuNAc was used for immunohistochemical staining.

RESULTS

Among these five STs, the mRNA expressions of three STs, including ST3Gal III, ST3Gal IV, and ST3Gal VI, were significantly decreased in patients with ovarian cancers, compared to the normal controls (P<0.001). By contrast, the mRNA expressions of ST3Gal I and ST6Gal I were increased in ovarian cancer tissues, compared to those of the normal controls (P<0.001). The ovarian epithelial carcinoma part showed strong positivity for MAA, whereas MAA staining in the stromal part was negative. Both the epithelial part and the stromal part of postmenopausal ovarian tissue showed negativity for MAA staining. However, clinico-pathological parameters, including stage, differentiation, amount of ascites, and serum levels of CA125, did not show any correlation to mRNA expression of any given-type ST.

CONCLUSIONS

Our results suggest that altered mRNA expressions of alpha2,3-sialyltransferase ST3Gal I, ST3Gal III, ST3Gal IV, ST3Gal VI, andalpha2,6-sialyltransferase ST6Gal I are of importance in malignant ovarian cancers. An increased expression of ST3Gal I may contribute directly to increased alpha2,3-linked sialylation in ovarian serous carcinoma.