Monoclonal Antibody to CD14, TLR4, or CD11b: Impact of Epitope and Isotype Specificity on ROS Generation by Human Granulocytes and Monocytes.

Lipopolysaccharides (LPSs or endotoxins) from Gram-negative bacteria represent pathogen-associated molecular patterns (PAMPs) that are recognized by CD14 and Toll-like receptor 4 (TLR4). Lipopolysaccharides prime polymorphonuclear leukocytes (PMNs) for substantial production of reactive oxygen species (ROS) during its response to secondary stimuli such as chemoattractants or pathogens. The excessive ROS production can damage surrounding host tissues, thereby amplifying the inflammatory reaction caused by pathogens. Today, specific antibodies against CD14, TLR4, and CD11b are being used as the essential tools to elucidate the role of these receptors in acute inflammation and some of these antibodies have advised as therapeutic agents for clinical use. Because each antibody has two antigen-binding arms [F(ab')2] and one Fc arm, its effect on cellular response is much more complicated rather than simple blockage of target receptor. In fact, IgG antibody, once bound to target receptor, engages Fc receptors γ (FcγRs) and thereby is able to activate the adaptive immune system. The consequences of antibody-dependent binary heterotypic association of CD14, TLR4, or CD11b with FcγRs as well as homotypic one on ROS production are not well elucidated. Moreover, the consequences of antigenic recognition of CD14, TLR4, or CD11b by specific F(ab')2 fragments are not always investigated. In this review, we will discuss known mechanisms underlying the therapeutic efficiency of CD14, TLR4, and CD11b/CD18 antibodies with a focus on LPS-dependent ROS or cytokine production by PMNs or monocytes. The impacts of F(ab')2 as well as antibody IgG subclasses (isotypes) in therapeutic efficiency or agonistic potency of known antibodies against abovementioned receptors are presented. We also pay attention to how the efficiency of different IgG antibody subclasses is modulated during LPS-induced inflammation and by production of priming agents such as interferon γ (IFN-γ). Our review reinforces the molecular targets and therapeutic approaches to amelioration of harmful consequences of excessive activation of human pattern recognition receptors.

The α7 nicotinic acetylcholine receptor positive allosteric modulator attenuates lipopolysaccharide-induced activation of hippocampal IκB and CD11b gene expression in mice.

We have reported that 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS), α7 nicotinic acetylcholine receptor (nAChR) positive allosteric modulator (PAM) reduces lipopolysaccharide (LPS)-induced hyperalgesia and allodynia in mice. The objective of the present study was to determine the effects of TQS on LPS-induced activation of hippocampal inhibitor of κB (IκB) and cluster of differentiation 11b (CD11b) gene expression involving hyperalgesia and allodynia in mice. We also examined the effects of TQS on microglial phenotype following LPS administration. Pretreatment of TQS (4 mg/kg) reduced the expressions of IκB and CD11b mRNA. Pretreatment of methyllycaconitine (3 mg/kg), an α7 nAChR antagonist, reversed TQS-induced decrease in IκB and CD11b mRNA expressions in the hippocampus indicating the involvement of α7 nAChR. In addition, TQS (4 mg/kg) reversed the LPS-induced microglial morphological changes. These results suggest that TQS reduces LPS-induced IκB and CD11b gene expression and microglial activation associated with hyperalgesia and allodynia by targeting microglial α7 nAChR in the hippocampus.

Activation of the CB2 receptor system reverses amyloid-induced memory deficiency.

Cannabinoid type 2 (CB(2)) agonists are neuroprotective and appear to play modulatory roles in neurodegenerative processes in Alzheimer's disease. We have studied the effect of 1-((3-benzyl-3-methyl-2,3-dihydro-1-benzofuran-6-yl) carbonyl) piperidine (MDA7)-a novel selective CB(2) agonist that lacks psychoactivity-on ameliorating the neuroinflammatory process, synaptic dysfunction, and cognitive impairment induced by bilateral microinjection of amyloid-ß (Aß)(1-40) fibrils into the hippocampal CA1 area of rats. In rats injected with Aß(1-40) fibrils, compared with the administration of intraperitoneal saline for 14 days, treatment with 15 mg/kg of intraperitoneal MDA7 daily for 14 days (1) ameliorated the expression of CD11b (microglia marker) and glial fibrillary acidic protein (astrocyte marker), (2) decreased the secretion of interleukin-1ß, (3) decreased the upsurge of CB(2) receptors, (4) promoted Aß clearance, and (5) restored synaptic plasticity, cognition, and memory. Our findings suggest that MDA7 is an innovative therapeutic approach for the treatment of Alzheimer's disease.

Further characterisation of the LPS model of Parkinson's disease: a comparison of intra-nigral and intra-striatal lipopolysaccharide administration on motor function, microgliosis and nigrostriatal neurodegeneration in the rat.

Chronic neuroinflammation has been established as one of the many processes involved in the pathogenesis of Parkinson's disease (PD). Because of this, researchers have attempted to replicate this pathogenic feature in animal models using the potent inflammagen, lipopolysaccharide (LPS), in order to gain better understanding of immune-mediated events in PD. However, although the effect of intra-cerebral LPS on neuroinflammation and neurodegeneration has been relatively well characterised, its impact on motor function has been less well studied. Therefore, the aim of this study was to further characterise the neuropathological and behavioural impact of intra-nigral and intra-striatal administration of LPS. To do, LPS (10 µg) or vehicle (sterile saline) were stereotaxically injected into the adult rat substantia nigra or striatum on one side only. The effect of LPS administration on lateralised motor function was assessed using the Corridor, Stepping and Whisker tests for two weeks post-injection, after which, amphetamine-induced rotational asymmetry was completed. Post-mortem, the impact of LPS on nigrostriatal degeneration and microgliosis was assessed using quantitative tyrosine hydroxylase and OX-42 immunohistochemistry respectively. We found that intra-nigral administration of LPS led to localised microgliosis in the substantia nigra and this was accompanied by nigrostriatal neurodegeneration and stable spontaneous motor deficits. In contrast, intra-striatal administration of LPS led to localised microgliosis in the striatum but this did not lead to any nigrostriatal neurodegeneration and only induced transient motor dysfunction. In conclusion, this study reveals the impact of intra-cerebral LPS administration on PD-related neuropathology and motor function, and it indicates that the intra-nigral model may be a highly relevant model as it is associated with stable motor decline underpinned by nigral microgliosis and nigrostriatal neurodegeneration.

Intragraft CD11b(+) IDO(+) cells mediate cardiac allograft tolerance by ECDI-fixed donor splenocyte infusions.

We have previously shown that pre- and post-transplant infusions of donor splenocytes treated with 1-ethyl-3-(3'-dimethylaminopropyl)-carbodiimide (ECDI-SPs) provide permanent donor-specific protection of islet allografts. The efficacy of donor ECDI-SPs in protecting vascularized cardiac allografts and mechanism(s) of protection are unknown. In this study, we show that infusions of ECDI-SPs significantly prolong cardiac allograft survival concomitant with an impressive accumulation of CD11b(+) IDO(+) cells in the cardiac allograft, and that the presence of this population is dependent on Gr1(+) cells. Consequently, depletion of Gr1(+) cells or inhibition of indoleamine 2,3 dioxygenase (IDO) activity abrogates graft protection by ECDI-SPs infusions. In addition, T cells from ECDI-SPs treated recipients secrete high levels of interleukin 10 and interleukin 13 upon in vitro restimulation, which are also dampened in recipients treated with the IDO inhibitor. Furthermore, combination of donor ECDI-SPs with a short course of rapamycin provides indefinite cardiac allograft survival in 100% of the recipients. These findings reveal a novel mechanism of donor ECDI-SPs in inducing cardiac transplant tolerance and provide several targets that are amenable to therapeutic manipulations for tolerance induction for cardiac transplantation.

Gu-4 suppresses affinity and avidity modulation of CD11b and improves the outcome of mice with endotoxemia and sepsis.

BACKGROUND: Systemic leukocyte activation and disseminated leukocyte adhesion will impair the microcirculation and cause severe decrements in tissue perfusion and organ function in the process of severe sepsis. Gu-4, a lactosyl derivative, could selectively target CD11b to exert therapeutic effect in a rat model of severe burn shock. Here, we addressed whether Gu-4 could render protective effects on septic animals. METHODOLOGY/PRINCIPAL FINDINGS: On a murine model of endotoxemia induced by lipopolysaccharide (LPS), we found that the median effective dose (ED50) of Gu-4 was 0.929 mg/kg. In vivo treatment of Gu-4 after LPS challenge prominently attenuated LPS-induced lung injury and decreased lactic acid level in lung tissue. Using the ED50 of Gu-4, we also demonstrated that Gu-4 treatment significantly improved the survival rate of animals underwent sepsis induced by cecal ligation and puncture. By adhesion and transwell migration assays, we found that Gu-4 treatment inhibited the adhesion and transendothelial migration of LPS-stimulated THP-1 cells. By flow cytometry and microscopy, we demonstrated that Gu-4 treatment inhibited the exposure of active I-domain and the cluster formation of CD11b on the LPS-stimulated polymorphonuclear leukocytes. Western blot analyses further revealed that Gu-4 treatment markedly inhibited the activation of spleen tyrosine kinase in LPS-stimulated THP-1 cells. CONCLUSIONS/SIGNIFICANCE: Gu-4 improves the survival of mice underwent endotoxemia and sepsis, our in vitro investigations indicate that the possible underlying mechanism might involve the modulations of the affinity and avidity of CD11b on the leukocyte. Our findings shed light on the potential use of Gu-4, an interacting compound to CD11b, in the treatment of sepsis and septic shock.

Statins decrease neuroinflammation and prevent cognitive impairment after cerebral malaria.

Cerebral malaria (CM) is the most severe manifestation of Plasmodium falciparum infection in children and non-immune adults. Previous work has documented a persistent cognitive impairment in children who survive an episode of CM that is mimicked in animal models of the disease. Potential therapeutic interventions for this complication have not been investigated, and are urgently needed. HMG-CoA reductase inhibitors (statins) are widely prescribed for cardiovascular diseases. In addition to their effects on the inhibition of cholesterol synthesis, statins have pleiotropic immunomodulatory activities. Here we tested if statins would prevent cognitive impairment in a murine model of cerebral malaria. Six days after infection with Plasmodium berghei ANKA (PbA) mice displayed clear signs of CM and were treated with chloroquine, or chloroquine and lovastatin. Intravital examination of pial vessels of infected animals demonstrated a decrease in functional capillary density and an increase in rolling and adhesion of leukocytes to inflamed endothelium that were reversed by treatment with lovastatin. In addition, oedema, ICAM-1, and CD11b mRNA levels were reduced in lovastatin-treated PbA-infected mice brains. Moreover, HMOX-1 mRNA levels are enhanced in lovastatin-treated healthy and infected brains. Oxidative stress and key inflammatory chemokines and cytokines were reduced to non-infected control levels in animals treated with lovastatin. Fifteen days post-infection cognitive dysfunction was detected by a battery of cognition tests in animals rescued from CM by chloroquine treatment. In contrast, it was absent in animals treated with lovastatin and chloroquine. The outcome was similar in experimental bacterial sepsis, suggesting that statins have neuroprotective effects in severe infectious syndromes in addition to CM. Statin treatment prevents neuroinflammation and blood brain barrier dysfunction in experimental CM and related conditions that are associated with cognitive sequelae, and may be a valuable adjuvant therapeutic agent for prevention of cognitive impairment in patients surviving an episode of CM.

2-(2-Fluorobenzamido)benzoate ethyl ester (EFB-1) inhibits superoxide production by human neutrophils and attenuates hemorrhagic shock-induced organ dysfunction in rats.

Neutrophil activation after trauma-hemorrhagic shock (T/H) has been implicated in the development of multiple organ dysfunction (MOD). In this study, we report that a small chemical compound, 2-(2-fluorobenzamido)benzoic acid ethyl ester (EFB-1), exhibited a potent inhibitory effect on the formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced superoxide anion (O2•-) release and CD11b expression by human neutrophils. Additionally, administration of EFB-1 in rats subjected to T/H caused a significant improvement in MOD. EFB-1 treatment induced an increase in cAMP formation and protein kinase (PK) A activity in FMLP-activated neutrophils, which occurred through the selective inhibition of cAMP-specific phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function or cGMP-specific PDE activity. FMLP-induced phosphorylation of protein kinase B (AKT), but not calcium mobilization, was reduced by EFB-1. The inhibitory effects of EFB-1 on O(2•-) production, CD11b expression, and AKT phosphorylation were reversed by PKA inhibitors (H89 and KT5720). Significantly, administration of EFB-1 (1 mg/kg body wt) attenuated the myeloperoxidase activity of the intestines, lungs, and liver and reduced the wet/dry weight ratio of the intestines and lungs and plasma alanine aminotransferase and aspartate aminotransferase levels in Sprague-Dawley rats after T/H. Therefore, EFB-1 is a new inhibitor of cAMP-specific PDE that potently suppresses O(2•-) release and CD11b expression by human neutrophils and attenuates T/H-induced MOD in rats.

Areca nut extracts enhance the development of CD11b(+) Gr-1(+) cells with the characteristics of myeloid-derived suppressor cells in antigen-stimulated mice.

BACKGROUND: Areca quid chewing is an etiological factor contributing to the development of oral cancer and pre-cancers, whose pathophysiology has been linked to inflammation and immune deterioration. Myeloid-derived suppressor cells (MDSC) play a key role in the regulation of immunity under certain pathological conditions, such as inflammation and cancer. As areca nut extracts (ANE) have been reported to induce a proinflammatory effect in antigen-stimulated mice, we hypothesized that ANE might enhance the development of MDSC. METHODS: Ovalbumin (OVA)-sensitized BALB/c mice were daily administered with ANE (5-50 mg/kg), polyphenol-enriched ANE (PANE; 25 mg/kg) or arecoline (5 mg/kg) by intraperitoneal injection for 10 doses. The mouse footpads were then subcutaneously challenged with OVA to induce local inflammatory responses. RESULTS: ANE and PANE treatment significantly increased the spleen index and the population of CD11b(+) Gr-1(+) cells in the spleen and peripheral blood, whereas arecoline was inactive. In addition, ANE and PANE treatment enhanced the expression of cytokines and enzymes associated with the immunosuppressive function of MDSC, including IL-10, arginase-I and iNOS in splenic CD11b(+) cells. Concordantly, ANE and PANE treatment augmented the infiltration of Gr-1(+) IL-10(+) cells in the footpads challenged with OVA. CONCLUSIONS: Our results suggested that areca nut constituents, in particular, polyphenols enhanced the development of myeloid-derived suppressor cells in vivo, which may be a critical mechanism linking inflammation and the compromised immunity reported to be associated with the pathophysiology of areca-related oral diseases.

Garenoxacin-induced increase of CD11b expression on human polymorphonuclear neutrophils does not affect phagocytosis and killing of Staphylococcus aureus.

Garenoxacin is considered to be the most active quinolone against Staphylococcus aureus. Quinolones are believed to alter the function of human polymorphonuclear leukocytes (PMN) and garenoxacin is known to be the only quinolone which alters the expression of the beta-chain (CD11b) of the complement receptor 3 (CR3) which is known to be important in the phagocytosis of S. aureus by PMN. Therefore, the effect of this altered CD11b expression on phagocytosis, oxidative burst, and killing of S. aureus was addressed and compared with that of standard quinolones. Phagocytosis and oxidative burst were determined by flow cytometry, and killing was measured by a colony-count method. Garenoxacin at therapeutic concentrations affected neither phagocytosis nor killing of Staphylococcus aureus NMS54. At supratherapeutic concentrations (1,500 mg/l) garenoxacin reduced and delayed phagocytosis like all other quinolones tested except norfloxacin. This decrease seems to be a result of inhibition of the oxidative burst of PMN and reduced CD11b expression at this supratherapeutic concentration. In conclusion, the alteration of CD11b expression of PMN caused by garenoxacin at 0.5, 5.0, and 100.0 mg/l is not considered to hamper the function of these first-line-defense phagocytes.

Kainic acid and 3-Nitropropionic acid induced expression of laminin in vascular elements of the rat brain.

Laminin is a glycoprotein component of the basement membrane and has been reported to be found in different areas of the nervous system including brain endothelial cells, Schwann cells and peripheral nerves. Although the in-vitro studies suggest that laminin plays an important role in growth and neurite extension of cultured neurons, localization of laminin in the brain has been controversial and inconsistent results have been reported. Recently, laminin immunoreactivity has been used as a marker for vascular elements in the brain. In this study, we have investigated the effect of two mechanistically different neurotoxins, kainic acid (KA), an NMDA agonist and 3-Nitropropionic acid (3-NPA), an inhibitor of mitochondrial respiration, on brain vascular elements revealed by laminin immunolabeling. We also explored whether administration of these two neurotoxic drugs correlate with the neuronal degeneration observed after neurotoxic insult by staining with Fluoro-Jade C dye. We have employed single immunolabeling to localize laminin in the brains. In KA treated rats, most of the laminin immunoreactivity is present in the piriform cortex, corpus callosum (myelinated tracts) amygdala, hippocampus, ventral thalamus and tenia tacta. In 3-NPA treated animals, laminin immunoreactivity was confined mostly to the striatum. In contrast, saline treated rats showed very little laminin immunolabeling around capillaries, arteries and in the meningeal membranes. To determine the effects of these neurotoxins on the integrity of the blood brain barrier (BBB), endothelial brain barrier antigen (EBA) immunolabeling was also performed. In addition, we performed CD11b immunolabeling to evaluate the effect of 3-NPA and KA on the activation of microglia in the brain. CD11b was dramatically increased in KA and 3-NPA treated animals. We have also combined laminin immunolabeling with Fluoro-Jade C labeling to evaluate the spatio-temporal association of degenerating neurons and the expression of laminin containing microvessels. Areas which showed intense laminin immunolabeling following KA or 3-NPA exposure correlated with those exhibiting the greatest number of degenerating neurons observed after Fluoro-Jade C staining. EBA-laminin double immunolabeling demonstrated that the expressions of laminin were predominantly localized in the areas (cortex, thalamus and hippocampus) where EBA has been either reduced or is absent. Our results from these experiments demonstrate that vascular laminin expression increases after treatment with KA or 3-NPA, suggesting the occurrence of neovascularization. Microglia may also contribute to the neurotoxic induced neovascularization and neurodegeneration.

The effect of midazolam on neutrophil mitogen-activated protein kinase.

BACKGROUND: Neutrophil p38 mitogen-activated protein kinase (MAPK) is a key enzyme in the intracellular signalling pathway that is responsible for many neutrophil functions, which are important in neutrophil-endothelial interaction. The imidazole compounds are inhibitors of this enzyme system. The objectives of this in-vitro investigation were to examine the effect of midazolam on neutrophil p38 MAPK activation (phosphorylation) following in-vitro ischaemia-reperfusion injury, and the expression of adhesion molecule CD11b/CD18. METHODS: In-vitro injury was produced by incubating the neutrophils with N-formyl-methionyl-leucyl-phenylalanine. Neutrophils were treated with either 10 or 50 times the therapeutic plasma concentrations of midazolam and SB203580 (known inhibitor of p38 MAPK). The concentrations of phosphorylated p38 MAPK and expression of neutrophil adhesion molecules CD11b/CD18 were measured. Flow cytometry was used to estimate adhesion molecule expression. RESULTS: The concentration of phosphorylated p38 MAPK was less in neutrophils subjected to ischaemia-reperfusion and treated with midazolam either 10 microg ml [13.6 (3.2) ng ml] or 50 microg ml [12.4 (3.6) ng ml], or SB203580 [13 (2.6) ng ml] than those subjected to ischaemia-reperfusion alone [18 (3.18) ng ml] at a P value of less than 0.05.Following ischaemia-reperfusion injury, CD11b/CD18 expression (expression mean channel fluorescence) on neutrophils was greater when compared with controls. The magnitudes of CD11b and CD18 expression on ischaemia-reperfusion-injured neutrophils were decreased by midazolam (10 microg ml) as compared with control of 10.3 (2.6) vs. 14 (3.1) microg ml and 28.3 (12.9) vs. 44 (12.1) microg ml, respectively, at a P value of less than 0.05. Similarly, the expression of CD11b and CD18 was less in ischaemia-reperfusion-injured neutrophils treated with inhibitor of 10.3 (2.8) vs. 14 (3.18) microg ml and 29.5 (12.5) vs. 44.3 (12.3) microg ml when compared with controls at a P value of less than 0.05. CONCLUSION: Midazolam diminishes in-vitro ischaemia-reperfusion-induced phosphorylation of p38 MAPK in neutrophils. This decrease in p38 MAPK activation results in decreased neutrophil CD11b/CD18 molecule expression.

Curcumin limits the fibrogenic evolution of experimental steatohepatitis.

Nonalcoholic steatohepatitis is characterized by the association of steatosis with hepatic cell injury, lobular inflammation and fibrosis. Curcumin is known for its antioxidant, anti-inflammatory and antifibrotic properties. The aim of this study was to test whether the administration of curcumin limits fibrogenic evolution in a murine model of nonalcoholic steatohepatitis. Male C57BL/6 mice were divided into four groups and fed a diet deficient in methionine and choline (MCD) or the same diet supplemented with methionine and choline for as long as 10 weeks. Curcumin (25 microg per mouse) or its vehicle (DMSO) was administered intraperitoneally every other day. Fibrosis was assessed by Sirius red staining and histomorphometry. Intrahepatic gene expression was measured by quantitative PCR. Hepatic oxidative stress was evaluated by staining for 8-OH deoxyguanosine. Myofibroblastic hepatic stellate cells (HSCs) were isolated from normal human liver tissue. The increase in serum ALT caused by the MCD diet was significantly reduced by curcumin after 4 weeks. Administration of the MCD diet was associated with histological steatosis and necro-inflammation, and this latter was significantly reduced in mice receiving curcumin. Curcumin also inhibited the generation of hepatic oxidative stress. Fibrosis was evident after 8 or 10 weeks of MCD diet and was also significantly reduced by curcumin. Curcumin decreased the intrahepatic gene expression of monocyte chemoattractant protein-1, CD11b, procollagen type I and tissue inhibitor of metalloprotease (TIMP)-1, together with protein levels of alpha-smooth muscle-actin, a marker of fibrogenic cells. In addition, curcumin reduced the generation of reactive oxygen species in cultured HSCs and inhibited the secretion of TIMP-1 both in basal conditions and after the induction of oxidative stress. In conclusion, curcumin administration effectively limits the development and progression of fibrosis in mice with experimental steatohepatitis, and reduces TIMP-1 secretion and oxidative stress in cultured stellate cells.

Identification of novel agonists of the integrin CD11b/CD18.

We report the identification of novel small molecule agonists of integrin CD11b/CD18, which increased, in a dose-dependent manner, the adhesion of the integrin CD11b/CD18 expressing cells to two physiologically relevant ligands: Fibrinogen and iC3b. Compound 6 showed an ex vivo EC(50) of 10.5 microM and in vitro selectivity for binding to the recombinant alphaA-domain of CD11b/CD18. In silico docking experiments suggest that the compounds recognized a hydrophobic cleft in the ligand-binding alphaA-domain, implying an allosteric mechanism of modulation of integrin affinity by this novel compound.

Immunomodulatory effect of Antrodia camphorata mycelia and culture filtrate.

AIM OF THE STUDY: Antrodia camphorata, a precious folkloric medicinal mushroom, has been used to treat tumorigenic diseases in Taiwan. This study was to investigate the innate immunity augmentation effects of different fractions prepared from hot water extracts of submerged cultured Antrodia camphorata (AC). MATERIALS AND METHODS: The cytokine induction potency of AC fraction in diluted peripheral blood culture was measured by ELISA. The effects of AC fraction on phagocytic activity and CD11b expression were measured by the ingestion of FITC-labeled Escherichia coli and by labeling with PE-labeled CD11b monoclonal antibody, respectively, using flow cytometry. The molecular mass of hot water-soluble polysaccharides and content of adenosine in AC fraction were determined by gel permeation chromatography (GPC) and HPLC, respectively. RESULTS: The mycelia fraction, Fr. M II, and culture filtrate fractions, Fr. E II and Fr. E III, showed the strongest TNF-alpha and IL-6 induction effect as a function of their concentration. These fractions (20mug/ml) also showed marked activity in enhancing phagocytosis in human polymorphonuclear neutrophils (PMN) and monocytes. In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose-dependently. Composition analysis suggested that immunomodulatory effect of mycelia is mainly attributed to the 10-20kDa polysaccharides and adenosine. CONCLUSIONS: These results provide evidences that Antrodia camphorata can modulate innate immunity and may serve as an adjuvant for tumor treatment.

Identification and characterization of NDT 9513727 [N,N-bis(1,3-benzodioxol-5-ylmethyl)-1-butyl-2,4-diphenyl-1H-imidazole-5-methanamine], a novel, orally bioavailable C5a receptor inverse agonist.

The complement system represents an innate immune mechanism of host defense that has three effector arms, the C3a receptor, the C5a receptor (C5aR), and the membrane attack complex. Because of its inflammatory and immune-enhancing properties, the biological activity of C5a and its classical receptor have been widely studied. Because specific antagonism of the C5aR could have therapeutic benefit without affecting the protective immune response, the C5aR continues to be a promising target for pharmaceutical research. The lack of specific, potent and orally bioavailable small-molecule antagonists has limited the clinical investigation of the C5aR. We report the discovery of NDT 9513727 [N,N-bis(1,3-benzodioxol-5-ylmethyl)-1-butyl-2,4-diphenyl-1H-imidazole-5-methanamine], a small-molecule, orally bioavailable, selective, and potent inverse agonist of the human C5aR. NDT 9513727 was discovered based on the integrated use of in vitro affinity and functional assays in conjunction with medicinal chemistry. NDT 9513727 inhibited C5a-stimulated responses, including guanosine 5'-3-O-(thio)triphosphate binding, Ca(2+) mobilization, oxidative burst, degranulation, cell surface CD11b expression and chemotaxis in various cell types with IC(50)s from 1.1 to 9.2 nM, respectively. In C5a competition radioligand binding experiments, NDT 9513727 exhibited an IC(50) of 11.6 nM. NDT 9513727 effectively inhibited C5a-induced neutropenia in gerbil and cynomolgus macaque in vivo. The findings suggest that NDT 9513727 may be a promising new entity for the treatment of human inflammatory diseases.

Activation of basophils by stem cell factor: comparison with insulin-like growth factor-I.

BACKGROUND: Basophils are an active participant in the pathogenesis of local inflammation in allergic diseases such as asthma, but it is not fully known how basophil activation is regulated in inflamed tissue. OBJECTIVE: In order to clarify the control mechanisms of basophil activation in chronic inflammation and at remodeling sites, we analyzed the effects of fibroblast-derived cytokines, stem cell factor (SCF), and insulin-like growth factor-I (IGF-I) on basophils. METHODS: The effects of SCF and IGF-I on degranulation and surface activation marker expression by basophils were assessed and compared. RESULTS: SCF enhanced human basophil histamine release elicited by some, but not all, secretagogues; degranulation in response to IgE- or FcepsilonRI-mediated stimulation and 12-o-tetradecanoyl-phorbol-13-acetate (TPA) was enhanced by SCF. SCF slightly enhanced ionophore A23187-induced histamine release by basophils from some donors, but it failed to affect the release elicited by monocyte chemoattractant protein-1 (MCP-1), formylmethionyl-leucyl-phenylalanine (FMLP) or C5a. The repertoire of secretagogues responsive to SCF was similar to that of IGF-I. Expression levels of both CD11b and CD69 markers were significantly enhanced by the combination of SCF and IGF-I. CONCLUSIONS: These results suggest that SCF and IGF-I may modify the activation of basophils in a similar and/or synergistic fashion. Interaction of basophils with these cytokines might be involved in the pathogenesis of local inflammation and the remodeling process in asthma.

Calcium entry inhibition during resuscitation from shock attenuates inflammatory lung injury.

Trauma and hemorrhagic shock (T/HS) induce a systemic inflammatory response syndrome (SIRS). Neutrophils (polymorphonuclear leukocytes [PMN]) and other cells involved in acute lung injury (ALI) are activated by Ca2+ entry. Thus, inhibiting Ca2+ entry might attenuate post-traumatic lung injury. Inhibiting voltage-operated (L-type) Ca2+ channels during shock could cause cardiovascular collapse, but PMN are "nonexcitable" cells, lack L-type channels, and mobilize Ca2+ via nonspecific channels. We previously showed that PMN Ca2+ entry requires sphingosine 1-phosphate synthesis by sphingosine kinase and that both sphingosine kinase inhibition and blockade of nonspecific channels attenuate ALI when begun before shock. Pretreatment for clinical injuries, however, is impractical. Therefore, we now studied whether Ca2+ entry inhibition that begun during resuscitation from T/HS could attenuate SIRS and ALI without causing hemodynamic compromise. Male Sprague-Dawley rats underwent laparotomy and fixed-pressure shock (mean arterial pressure, 35 +/- 5 mmHg; 90 min). Sphingosine kinase inhibition or nonspecific Ca2+ channel inhibition was begun after resuscitation with 10% of shed blood. We then studied in vivo PMN activation and associated lung injury in the presence or absence of Ca2+ entry inhibition. Neither treatment worsened shock. Each treatment decreased CD11b expression, respiratory burst, PMN p38 MAP-kinase phosphorylation, PMN sequestration, and lung capillary leak in vivo. The similar results seen with two different forms of inhibition strengthen the conclusion that the biological effects seen were specific for calcium entry inhibition. Ca2+ entry inhibition is a candidate therapy for management of lung injury after shock.

Silymarin, a flavonoid from milk thistle (Silybum marianum L.), inhibits UV-induced oxidative stress through targeting infiltrating CD11b+ cells in mouse skin.

Phytochemicals have shown promise in inhibiting UV-induced oxidative stress, and therefore are considered as potent inhibitors of UV-induced oxidative stress-mediated skin diseases. We have shown previously that topical treatment of silymarin, a flavonoid from milk thistle (Silybum marianum), inhibits UV-induced oxidative stress in mouse skin. However, the cellular targets responsible for the inhibition of UV-induced oxidative stress by silymarin are not clearly defined. To address this issue, C3H/HeN mice were UV irradiated (90 mJ cm(-2)) with or without topical treatment with silymarin (1 mg cm(-2) skin area). Mice were killed 48 h later and skin samples collected. Flow cytometric analysis of viable dermal cells revealed that the number of infiltrating CD11b+ cells were the major source of oxidative stress (31.8%) in UV-irradiated skin compared with non-UV-exposed skin (0.4%). Treatment of silymarin inhibited UV-induced oxidative stress through inhibition of infiltrating CD11b+ cells. The analysis of myeloperoxidase also indicated that silymarin significantly (P < 0.001) decreased UV-induced infiltration of leukocytes, and this effect of silymarin was similar to that of intraperitoneal treatment of mice with monoclonal antibodies to CD11b. The inhibitory effect of silymarin, regardless of whether it is topically treated before or after UV irradiation, was of similar magnitude. Intraperitoneal administration of monoclonal antibodies to CD11b (rat IgG2b) to C3H/HeN mice inhibited UVB-induced oxidative stress generated by both epidermal and dermal cells as is evident by relative fluorescence intensity of oxidized rhodamine. Similar to the effect of anti-CD11b, silymarin also inhibited UV-induced oxidative stress in both epidermal and dermal cells. Further, CD11b+ and CD11b- cell subsets from UV-treated or silymarin+UV-treated mice were separated by immunomagnetic cell isolation technique from total epidermal and dermal single cell suspensions and analyzed for reactive oxygen species (ROS)/H2O2 production. Analytic data revealed that CD11b+ cell population from UV-irradiated skin resulted in significantly higher production of ROS in both epidermis and dermis than CD11b- cell population, and that silymarin inhibited UV-induced oxidative stress through targeting infiltrating the CD11b+ cell type in the skin.

The MDM-2 antagonist nutlin-3 promotes the maturation of acute myeloid leukemic blasts.

The small-molecule inhibitor of murine double minute (MDM-2), Nutlin-3, induced variable apoptosis in primary acute myeloid leukemia (AML) blasts and promoted myeloid maturation of surviving cells, as demonstrated by analysis of CD11b and CD14 surface antigens and by morphologic examination. Although the best-characterized activity of Nutlin-3 is activation of the p53 pathway, Nutlin-3 induced maturation also in one AML sample characterized by p53 deletion, as well as in the p53(-/-) human myeloblastic HL-60 cell line. At the molecular level, the maturational activity of Nutlin-3 in HL-60 cells was accompanied by the induction of E2F1 transcription factor, and it was significantly counteracted by specific gene knockdown with small interfering RNA for E2F1. Moreover, Nutlin-3, as well as tumor necrosis factor (TNF) alpha, potentiated the maturational activity of recombinant TNF-related apoptosis-inducing ligand (TRAIL) in HL-60 cells. However, although TNF-alpha significantly counteracted the proapoptotic activity of TRAIL, Nutlin-3 did not interfere with the proapoptotic activity of TRAIL. Taken together, these data disclose a novel, potentially relevant therapeutic role for Nutlin-3 in the treatment of both p53 wild-type and p53(-/-) AML, possibly in association with recombinant TRAIL.