MCP-5 suppresses osteoclast differentiation through Ccr5 upregulation

Human monocyte chemoattractant protein-1 (MCP-1) in mice has two orthologs, MCP-1 and MCP-5. MCP-1, which is highly expressed in osteoclasts rather than in osteoclast precursor cells, is an important factor in osteoclast differentiation. However, the roles of MCP-5 in osteoclasts are completely unknown. In this study, contrary to MCP-1, MCP-5 was downregulated during receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation and was considered an inhibitory factor in osteoclast differentiation. The inhibitory role of MCP-5 in osteoclast differentiation was closely related to the increase in Ccr5 expression and the inhibition of IκB degradation by RANKL. Transgenic mice expressing MCP-5 controlled by Mx-1 promoter exhibited an increased bone mass because of a decrease in osteoclasts. This result strongly supported that MCP-5 negatively regulated osteoclast differentiation. MCP-5 also prevented severe bone loss caused by RANKL.

Macrophage-Specific MCPIP1/Regnase-1 Attenuates Kidney Ischemia-Reperfusion Injury by Shaping the Local Inflammatory Response and Tissue Regeneration

Sterile inflammation either resolves the initial insult or leads to tissue damage. Kidney ischemia/reperfusion injury (IRI) is associated with neutrophilic infiltration, enhanced production of inflammatory mediators, accumulation of necrotic cells and tissue remodeling. Macrophage-dependent microenvironmental changes orchestrate many features of the immune response and tissue regeneration. The activation status of macrophages is influenced by extracellular signals, the duration and intensity of the stimulation, as well as various regulatory molecules. The role of macrophage-derived monocyte chemoattractant protein-induced protein 1 (MCPIP1), also known as Regnase-1, in kidney ischemia-reperfusion injury (IRI) and recovery from sterile inflammation remains unresolved. In this study, we showed that macrophage-specific Mcpip1 deletion significantly affects the kidney phenotype. Macrophage-specific Mcpip1 transgenic mice displayed enhanced inflammation and loss of the tubular compartment upon IRI. We showed that MCPIP1 modulates sterile inflammation by negative regulation of Irf4 expression and accumulation of IRF4+ cells in the tissue and, consequently, suppresses the post-ischemic kidney immune response. Thus, we identified MCPIP1 as an important molecular sentinel of immune homeostasis in experimental acute kidney injury (AKI) and renal fibrosis.

Hippo-YAP/MCP-1 mediated tubular maladaptive repair promote inflammation in renal failed recovery after ischemic AKI

Acute kidney injury (AKI) is associated with significant morbidity and its chronic inflammation contributes to subsequent chronic kidney disease (CKD) development. Yes-associated protein (YAP), the major transcriptional coactivator of the Hippo pathway, has been shown associated with chronic inflammation, but its role and mechanism in AKI-CKD transition remain unclear. Here we aimed to investigate the role of YAP in AKI-induced chronic inflammation. Renal ischemia/reperfusion (I/R) was used to induce a mouse model of AKI-CKD transition. We used verteporfin (VP), a pharmacological inhibitor of YAP, to treat post-IRI mice for a period, and evaluated the influence of YAP inhibition on long-term outcomes of AKI. In our results, severe IRI led to maladaptive tubular repair, macrophages infiltration, and progressive fibrosis. Following AKI, the Hippo pathway was found significantly altered with YAP persistent activation. Besides, tubular YAP activation was associated with the maladaptive repair, also correlated with interstitial macrophage infiltration. Monocyte chemoattractant protein 1 (MCP-1) was found notably upregulated with YAP activation. Of note, pharmacological inhibition of YAP in vivo attenuated renal inflammation, including macrophage infiltration and MCP-1 overexpression. Consistently, in vitro oxygen-glucose deprivation and reoxygenation (OGD/R) induced YAP activation and MCP-1 overproduction whereas these could be inhibited by VP. In addition, we modulated YAP activity by RNA interference, which further confirmed YAP activation enhances MCP-1 expression. Together, we concluded tubular YAP activation with maladaptive repair exacerbates renal inflammation probably via promoting MCP-1 production, which contributes to AKI-CKD transition.

Single-cell transcriptomics combined with interstitial fluid proteomics defines cell type-specific immune regulation in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, but its complex pathogenesis is only insufficiently understood, resulting in still limited treatment options.

OBJECTIVE

We sought to characterize AD on both transcriptomic and proteomic levels in humans.

METHODS

We used skin suction blistering, a painless and nonscarring procedure that can simultaneously sample skin cells and interstitial fluid. We then compared results with conventional biopsies.

RESULTS

Suction blistering captured epidermal and most immune cells equally well as biopsies, except for mast cells and nonmigratory CD163+ macrophages that were only present in biopsy isolates. Using single-cell RNA sequencing, we found comparable transcriptional profiles of key inflammatory pathways between blister and biopsy AD, but suction blistering was superior in cell-specific resolution for high-abundance transcripts (KRT1/KRT10, KRT16/KRT6A, S100A8/S100A9), which showed some background signals in biopsy isolates. Compared with healthy controls, we found characteristic upregulation of AD-typical cytokines such as IL13 and IL22 in Th2 and Th22 cells, respectively, but we also discovered these mediators in proliferating T cells and natural killer T cells, that also expressed the antimicrobial cytokine IL26. Overall, not T cells, but myeloid cells were most strongly enriched in AD, and we found dendritic cell (CLEC7A, amphiregulin/AREG, EREG) and macrophage products (CCL13) among the top upregulated proteins in AD blister fluid proteomic analyses.

CONCLUSION

These data show that by using cutting-edge technology, suction blistering offers several advantages over conventional biopsies, including better transcriptomic resolution of skin cells, combined with proteomic information from interstitial fluid, unraveling novel inflammatory players that shape the cellular and proteomic microenvironment of AD.

Borrelia burgdorferi basic membrane protein A stimulates murine macrophage to secrete specific chemokines

In this study, we investigated the mechanisms that lead to the production of proinflammatory mediators by the murine macrophage cell line, RAW264.7, when these cells are exposed in vitro to recombinant Borrelia burgdorferi basic membrane protein A (rBmpA). Using antibody protein microarray technology with high-throughput detection ability for detecting 25 chemokines in culture supernatant the RAW264.7 cell culture supernatants at 12 and 24 h post-stimulation with rBmpA, we identified two chemokines, a monocyte chemoattractant protein-5 (MCP-5/CCL12) and a macrophage inflammatory protein-2 (MIP-2/CXCL2), both of which increased significantly after stimulation. We then chose these two chemokines for further study. Enzyme-linked immunosorbent assay and real-time polymerase chain reaction revealed that with the increase of rBmpA concentration, MCP-5/CCL12 and MIP-2/CXCL2 showed concentration-dependent increases (p <0.01).Our results indicate that the rBmpA could stimulate the secretion of several specific chemokines and induce Lyme arthritis.

B-cell leukemia/lymphoma 10 promotes angiogenesis in an experimental corneal neovascularization model

PURPOSE

Corneal neovascularization (CrNV) arises from many causes including corneal inflammatory, infectious, or traumatic insult, and frequently leads to impaired vision. This study seeks to determine the role of B-cell leukemia/lymphoma 10 (BCL-10) in the development of experimental CrNV.

METHODS

Corneas from BCL-10 knockout (KO) mice and wild-type (WT) mice were burned by sodium hydroxide (NaOH) to create the CrNV model and neovascular formation in the corneas was assessed 2 weeks later. Intracorneal macrophage accumulation and the expression of angiogenic factors were quantified by flow cytometric analysis (FCM) and real-time PCR, respectively.

RESULTS

The amount of CrNV was determined 2 weeks after alkali burn. Compared to WT mice, the amount of CrNV in BCL-10 KO mice was significantly decreased. FCM revealed that F4/80-positive macrophages were markedly decreased in BCL-10 KO mice compared with WT mice. Reverse transcription PCR showed that the mRNA expression levels of intracorneal vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (bFGF) and monocyte chemotactic protein 1 were reduced in BCL-10 KO mice compared with WT mice.

CONCLUSION

BCL-10 KO mice exhibited reduced alkali-induced CrNV by suppressing intracorneal macrophage infiltration, which subsequently led to decreased VEGF-A and bFGF expression, suggesting that BCL-10 may become a potential clinical intervening target of CrNV.

In vitro and in vivo antimicrobial activity of a synthetic peptide derived from the C-terminal region of human chemokine CCL13 against Pseudomonas aeruginosa

Chemokines are important mediators of immunological responses during inflammation and under steady-state conditions. In addition to regulating cell migration, some chemotactic cytokines have direct effects on bacteria. Here, we characterized the antibacterial ability of the synthetic oligopeptide CCL13_57-75, which corresponds to the carboxyl-terminal region of the human chemokine CCL13. In vitro measurements indicated that CCL13_57-75 disrupts the cell membrane of Pseudomonas aeruginosa through a mechanism coupled to an unordered-helicoidal conformational transition. In a murine pneumonic model, CCL13_57-75 improved mouse survival and bacterial clearance and decreased neutrophil recruitment, proinflammatory cytokines and lung pathology compared with that observed in untreated infected animals. Overall, our study supports the ability of chemokines and/or chemokine-derived oligopeptides to act as direct defense agents against pathogenic bacteria and suggests their potential use as alternative antibiotics.

MMP-2 and 9 in Chronic Kidney Disease

Gelatinases are members of the matrix metalloproteinase (MMPs) family; they play an important role in the degradation of the extracellular matrix (ECM). This effect is also crucial in the development and progression of chronic kidney disease (CKD). Its expression, as well as its activity regulation are closely related to the cell signaling pathways, hypoxia and cell membrane structural change. Gelatinases also can affect the development and progression of CKD through the various interactions with tumor necrosis factors (TNFs), monocyte chemoattractant proteins (MCPs), growth factors (GFs), oxidative stress (OS), and so on. Currently, their non-proteolytic function is a hot topic of research, which may also be associated with the progression of CKD. Therefore, with the in-depth understanding about the function of gelatinases, we can have a more specific and accurate understanding of their role in the human body.

Linked production of pyroglutamate-modified proteins via self-cleavage of fusion tags with TEV protease and autonomous N-terminal cyclization with glutaminyl cyclase in vivo

Overproduction of N-terminal pyroglutamate (pGlu)-modified proteins utilizing Escherichia coli or eukaryotic cells is a challenging work owing to the fact that the recombinant proteins need to be recovered by proteolytic removal of fusion tags to expose the N-terminal glutaminyl or glutamyl residue, which is then converted into pGlu catalyzed by the enzyme glutaminyl cyclase. Herein we describe a new method for production of N-terminal pGlu-containing proteins in vivo via intracellular self-cleavage of fusion tags by tobacco etch virus (TEV) protease and then immediate N-terminal cyclization of passenger target proteins by a bacterial glutaminyl cyclase. To combine with the sticky-end PCR cloning strategy, this design allows the gene of target proteins to be efficiently inserted into the expression vector using two unique cloning sites (i.e., SnaB I and Xho I), and the soluble and N-terminal pGlu-containing proteins are then produced in vivo. Our method has been successfully applied to the production of pGlu-modified enhanced green fluorescence protein and monocyte chemoattractant proteins. This design will facilitate the production of protein drugs and drug target proteins that possess an N-terminal pGlu residue required for their physiological activities.

Absence of CC chemokine receptors 2a and 2b from human adipose lineage cells

Previous results have suggested the existence of receptors for monocyte chemoattractant protein-1 (MCP-1), CC chemokine receptors 2 (CCR2), in human adipocytes and their involvement in mediating effects of MCP-1 on adipocyte functions. However, the presence of CCR2 present on non-adipose-lineage cells of adipose tissue has not been excluded. We have used human Simpson-Golabi-Behmel-Syndrome (SGBS) preadipocytes and in-vitro-differentiated mature adipocytes to investigate the expression of CCR2 in human (pre)adipocytes. We found that the cells are devoid of CCR2 receptor protein and mRNA expression and fail to respond to treatment with all known CCR2 chemokine agonists. CCR2 is also absent from (pre)adipocytes prepared in vitro from human multipotent adipose-derived stem cells, bone-marrow-derived mesenchymal stem cells, or from primary (pre)adipocytes. Conditions mimicking proinflammatory changes in adipose tissue did not induce CCR2 receptor expression. We conclude that CCR2 is absent from human adipose lineage cells. Functional effects previously described for MCP-1 in human adipose tissue may be mediated indirectly through paracrine effects on non-adipose-lineage cells or by a (pre)adipocyte receptor for MCP-1 distinct from CCR2.

Bindarit inhibits human coronary artery smooth muscle cell proliferation, migration and phenotypic switching

Bindarit, a selective inhibitor of monocyte chemotactic proteins (MCPs) synthesis, reduces neointimal formation in animal models of vascular injury and recently has been shown to inhibit in-stent late loss in a placebo-controlled phase II clinical trial. However, the mechanisms underlying the efficacy of bindarit in controlling neointimal formation/restenosis have not been fully elucidated. Therefore, we investigated the effect of bindarit on human coronary smooth muscle cells activation, drawing attention to the phenotypic modulation process, focusing on contractile proteins expression as well as proliferation and migration. The expression of contractile proteins was evaluated by western blot analysis on cultured human coronary smooth muscle cells stimulated with TNF-α (30 ng/mL) or fetal bovine serum (5%). Bindarit (100-300 µM) reduced the embryonic form of smooth muscle myosin heavy chain while increased smooth muscle α-actin and calponin in both TNF-α- and fetal bovine serum-stimulated cells. These effects were associated with the inhibition of human coronary smooth muscle cell proliferation/migration and both MCP-1 and MCP-3 production. The effect of bindarit on smooth muscle cells phenotypic switching was confirmed in vivo in the rat balloon angioplasty model. Bindarit (200 mg/Kg/day) significantly reduced the expression of the embryonic form of smooth muscle myosin heavy chain, and increased smooth muscle α-actin and calponin in the rat carodid arteries subjected to endothelial denudation. Our results demonstrate that bindarit induces the differentiated state of human coronary smooth muscle cells, suggesting a novel underlying mechanisms by which this drug inhibits neointimal formation.

Fibrogenic and redox-related but not proinflammatory genes are upregulated in Lewis rat model of chronic silicosis

Silicosis, a fibrotic granulomatous lung disease, may occur through accidental high-dose or occupational inhalation of silica, leading to acute/accelerated and chronic silicosis, respectively. While chronic silicosis has a long asymptomatic latency, lung inflammation and apoptosis are hallmarks of acute silicosis. In animal models, histiocytic granulomas develop within days after high-dose intratracheal (IT) silica instillation. However, following chronic inhalation of occupationally relevant doses of silica, discrete granulomas resembling human silicosis arise months after the final exposure without significant lung inflammation/apoptosis. To identify molecular events associated with chronic silicosis, lung RNA samples from controls or subchronic silica-exposed rats were analyzed by Affymetrix at 28 wk after silica exposures. Results suggested a significant upregulation of 144 genes and downregulation of 7 genes. The upregulated genes included complement cascade, chemokines/chemokine receptors, G-protein signaling components, metalloproteases, and genes associated with oxidative stress. To examine the kinetics of gene expression relevant to silicosis, quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), Luminex-bead assays, Western blotting, and/or zymography were performed on lung tissues from 4 d, 28 wk, and intermediate times after subchronic silica exposure and compared with 14-d acute silicosis samples. Results indicated that genes regulating fibrosis (secreted phosphoprotein-1, Ccl2, and Ccl7), redox enzymes (superoxide dismutase-2 and arginase-1), and the enzymatic activities of matrix metalloproteinases 2 and 9 were upregulated in acute and chronic silicosis models. However, proinflammatory cytokines were strongly upregulated only in acute silicosis. Thus, inflammatory cytokines are associated with acute but not chronic silicosis. Data suggest that genes regulating fibrosis, oxidative stress, and metalloproteases may contribute to both acute and chronic silicosis.

Tissue distribution and expression of paraoxonases and chemokines in mouse: the ubiquitous and joint localisation suggest a systemic and coordinated role

A vicious cycle between oxidation and inflammation leads to complications in a growing number of disease states. Knowledge on tissue distribution of chemokines, mediators of inflammatory response, and paraoxonases, with antioxidant and anti-inflammatory actions, may be relevant. Using immunohistochemistry and quantitative real-time PCR we have investigated the distribution of PON1, 2 and 3, CCL2, 7, 8 and 12 and the chemokine receptor CCR2 protein and mRNA in 23 tissues from C57BL/6J mice. As expected, PON1, 2 and 3, CCL2, 7, 8 and 12 and CCR2 proteins were present in the vast majority of tissues investigated. Surprisingly, mRNA for these proteins was also expressed in most of these tissues suggesting local production and the ability to respond in situ to inflammatory stimuli. The wide distribution and expression of mRNA for paraoxonases and CC-chemokines suggest a systemic, probably coordinated, role in the overall inflammatory response.

Pulmonary and systemic expression of monocyte chemotactic proteins in preterm sheep fetuses exposed to lipopolysaccharide-induced chorioamnionitis

Monocyte chemoattractant proteins (MCP-1 and MCP-2) mediate monocyte and T-lymphocyte chemotaxis, and IL-1 contributes to the pathogenesis of chorioamnionitis-induced lung inflammation and fetal inflammatory responses. We tested the hypothesis that IL-1 mediates the systemic and pulmonary induction of MCP-1 and MCP-2 in response to lipopolysaccharide (LPS)-induced chorioamnionitis. MCP-1 mRNA, MCP-2 mRNA, and MCP-1 protein expression were measured in two models: 1) intra-amniotic LPS and 2) intra-amniotic recombinant sheep IL-1alpha given at varying intervals before preterm delivery at 124 d GA. Intra-amniotic LPS or IL-1alpha induced MCP-1 mRNA and protein and MCP-2 mRNA in fetal lung many fold at 1-2 d. LPS induced intense MCP-1 expression in subepithelial mesenchymal cells and interstitial inflammatory cells in the lung. Inhibition of IL-1 signaling with recombinant human IL-1 receptor antagonist (rhIL-1ra) did not attenuate LPS induced increase in MCP-1 or MCP-2 expression. MCP-1 and MCP-2 were not induced in liver or chorioamnion, but MCP-1 increased in cord plasma. LPS or IL-1 can induce robust expression of MCP-1 or MCP-2 in the fetal lung. LPS induction of MCP-1 is not IL-1 dependent in fetal sheep. MCP-1 and MCP-2 may be significant contributors to fetal inflammation.

Effect of an immunotoxin to folate receptor beta on bleomycin-induced experimental pulmonary fibrosis

It has been suggested that alveolar and interstitial macrophages play a key role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) by producing proinflammatory and/or fibrogenic cytokines. We showed that inflammatory macrophages expressed folate receptor beta (FRbeta) while resident macrophages in normal tissues expressed no or low levels of FRbeta. In the present study, we examined the distribution of FRbeta-expressing macrophages in the lungs of patients with usual idiopathic pulmonary fibrosis (UIP) and mice with bleomycin-induced pulmonary fibrosis (PF) and tested whether the depletion of FRbeta-expressing macrophages could suppress bleomycin-induced PF in mice. Immunostaining with anti-human or -mouse FRbeta monoclonal antibody (mAb) revealed that FRbeta-expressing macrophages were present predominantly in fibrotic areas of the lungs of patients with UIP and mice with bleomycin-induced PF. Intranasal administration of a recombinant immunotoxin, consisting of immunoglobulin heavy and light chain Fv portions of an anti-mouse FRbeta mAb and truncated Pseudomonas exotoxin A, increased survival significantly and reduced levels of total hydroxyproline and fibrosis in bleomycin-induced PF. In immunohistochemical analysis, decreased numbers of tumour necrosis factor-alpha-, chemokines CCL2- and CCL12-producing cells were observed in the immunotoxin-treated group. These findings suggest a pathogenic role of FRbeta-expressing macrophages in IPF. Thus, targeting FRbeta-expressing macrophages may be a promising treatment of IPF.

Monocyte chemoattractant proteins mediate myocardial microvascular dysfunction in swine renovascular hypertension

BACKGROUND

Monocyte chemoattractant proteins (MCPs) play an important role in mediating inflammatory processes. Hypertension (HTN) is associated with inflammation as well as impaired cardiac microcirculatory function and structure, but the contribution of MCPs to these alterations remained unclear. This study tested the hypothesis that MCPs regulate cardiac microvascular function and structure in experimental HTN.

METHODS AND RESULTS

Pigs (n=6 per group) were studied after 10 weeks of normal, renovascular HTN, or renovascular HTN+ bindarit (MCPs inhibitor, 50 mg/kg/d PO). Left ventricular (LV) function, myocardial microvascular permeability, and fractional vascular volume were assessed by fast computed tomography before and after adenosine infusion (400 microg/kg/min). Myocardial fibrosis, inflammation, and microvascular remodeling were determined ex vivo. Hypertension was not altered by bindarit, but LV hypertrophy and diastolic function were improved. In response to adenosine, myocardial microvascular permeability increased in HTN (from 0.0083+/-0.0009 to 0.0103+/-0.0011 AU, P=0.038 versus baseline) and fractional vascular volume decreased, whereas both remained unchanged in normal and HTN+bindarit pigs. HTN upregulated endothelin-1 expression, myocardial inflammation, and microvascular wall thickening, which were inhibited by bindarit.

CONCLUSIONS

MCPs partly mediate myocardial inflammation, fibrosis, vascular remodeling, and impaired vascular integrity induced by hypertension. Inhibition of MCPs could potentially be a therapeutic target in hypertensive cardiomyopathy.

A role of monocyte chemoattractant protein-4 (MCP-4)/CCL13 from chondrocytes in rheumatoid arthritis

We studied the role of monocyte chemoattractant (MCP)-4/CCL13 in the pathogenesis of rheumatoid arthritis (RA). MCP-4 was highly expressed in cartilage from RA patients. Interferon-gamma significantly stimulated MCP-4/CCL13 production in human chondrocytes, and this effect was enhanced in combination with interleukin-1beta or tumor necrosis factor-alpha. MCP-4/CCL13 induces the phosphorylation of extracellular signal-regulated kinase in fibroblast-like synoviocytes and activates cell proliferation, and PD98059 completely inhibits these effects. These data suggest that interferon-gamma in combination with interleukin-1beta/tumor necrosis factor-alpha activates the production of MCP-4/CCL13 from chondrocytes in RA joints, and that secreted MCP-4/CCL13 enhances fibroblast-like synoviocyte proliferation by activating the extracellular signal-regulated kinase mitogen-activated protein kinase cascade.

Expression of MCP-4 by TLR ligand-stimulated nasal polyp fibroblasts

CONCLUSION

These results indicate that nasal polyp fibroblasts contribute to innate immunity and eosinophilic inflammation such as nasal polyposis.

OBJECTIVE

It is generally accepted that type 2 T helper (Th2) cytokines and some chemoattractants play an essential role in the pathogenesis of nasal polyposis. Nasal polyposis is characterized by chronic eosinophilic inflammation. The mechanisms that cause the predominance of eosinophilic infiltration in nasal polyposis have yet to be clarified. There is growing evidence that fibroblasts could be a major source of Th2 chemokines. Because the nasal and paranasal mucosae are the first respiratory tissues that environmental agents encounter, those tissues are exposed to injurious agents, including microorganisms and their breakdown products. We investigated whether nasal polyp fibroblasts produce a C-C chemokine, MCP-4, when stimulated with the breakdown products of microorganisms and a Th2 cytokine (interleukin (IL)-4).

MATERIALS AND METHODS

Fibroblast lines were established from nasal polyp tissues. The expression of MCP-4 mRNA was evaluated by real-time RT-PCR. The amount of MCP-4 in the supernatants was measured by ELISA.

RESULTS

TLR2, 3, 4 and 5 ligands, but not TLR7/8 or 9 ligands, induced small amounts of MCP-4. TLR2, 3, 4 and 5 ligands synergized with IL-4 to induce the production of MCP-4.

CXCR2 Blockade Impairs Angiotensin II–Induced CC Chemokine Synthesis and Mononuclear Leukocyte Infiltration

Objective— Angiotensin II (Ang-II) and mononuclear leukocytes are involved in atherosclerosis. This study reports the inhibition of Ang-II–induced mononuclear cell recruitment by CXCR2 antagonism and the mechanisms involved.

Methods and Results— Ang-II (1 nmol/L, i.p. in rats) induced CXC and CC chemokines, followed by neutrophil and mononuclear cell recruitment. Administration of the CXCR2 antagonist, SB-517785-M, inhibited the infiltration of both neutrophils (98%) and mononuclear cells (60%). SB-517785-M had no effect on the increase in CXC chemokine levels but reduced MCP-1, RANTES, and MIP-1α release by 66%, 63%, and 80%, respectively. Intravital microscopy showed that pretreatment with SB-517785-M inhibited Ang-II–induced arteriolar mononuclear leukocyte adhesion. Stimulation of human umbilical arterial endothelial cells (HUAECs) or whole blood with 1 μmol/L Ang-II induced the synthesis of chemokines. Ang-II increased HUAEC CXCR2 expression, and its blockade caused a significant reduction of MCP-1, -3, and RANTES release, as well as mononuclear cell arrest. Ang-II–induced MIP-1α release from blood cells was also inhibited.

Conclusion— Mononuclear leukocyte recruitment induced by Ang-II is, surprisingly, largely mediated by the CXC chemokines which appear to induce the release of CC chemokines. Therefore, CXC chemokine receptor antagonists may help to prevent mononuclear cell infiltration and the progression of the atherogenic process.

Differential regulation of chemokine expression by Th1 and Th2 cytokines and mechanisms of eotaxin/CCL-11 expression in human airway smooth muscle cells

BACKGROUND

Airway smooth muscle (ASM) cells may contribute to the pathogenesis of asthma including airway inflammation and remodeling. We focused our study on the regulation of chemokine expression by cytokines and analyzed the mechanisms of eotaxin/CCL-11 expression in ASM cells.

METHODS

Human ASM cells were cultured in vitro and treated with IL-4, interferon-gamma (IFNgamma), and tumor necrosis factor-alpha (TNFalpha). Secretion of chemokines into the culture medium was analyzed by ELISA. Expression of eotaxin mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Binding of transcription factor signal transducer activator of transcription (STAT) 6 to the eotaxin promoter-derived DNA was analyzed by pull-down Western blot. To assess transcriptional regulation of eotaxin, cells were transfected with eotaxin promoter-luciferase reporter plasmids, and activity was determined by dual luciferase assay.

RESULTS

The Th2 cytokine IL-4 preferentially stimulated the expression of the CC chemokine receptor (CCR) 3-ligand chemokines eotaxin, eotaxin-3, and MCP-4. The Th1 cytokine IFNgamma stimulated the expression of chemokines IP-10 and RANTES. IL-4 stimulated nuclear translocation of signal transducer activator of transcription 6 (STAT6) and its binding to the eotaxin promoter region. IL-4 activated the eotaxin promoter and its activity was inhibited by mutation of the binding site for STAT6 in the promoter.

CONCLUSIONS

The Th2 cytokine IL-4 preferentially stimulated the expression of CCR3 ligand chemokines including eotaxin in ASM cells. The transcription factor STAT6 may play a pivotal role in the activation of eotaxin transcription in response to IL-4.

Calcium-sensing receptor stimulates secretion of an interferon-γ-induced monokine (CXCL10) and monocyte chemoattractant protein-3 in immortalized GnRH neurons

Biology of GnRH neurons is critically dependent on extracellular Ca(2+) (Ca(2+) (o)). We evaluated differences in gene expression patterns with low and high Ca(2+) (o) in an immortalized GnRH neuron line, GT1-7 cells. Mouse global oligonucleotide microarray was used to evaluate transcriptional differences among the genes regulated by elevated Ca(2+) (o). Our result identified two interferon-gamma (IFNgamma)-inducible chemokines, CXCL9 and CXCL10, and a beta chemokine, monocyte chemoattractant protein-3 (MCP-3/CCL7), being up-regulated in GT1-7 cells treated with high Ca(2+) (o) (3.0 mM) compared with low Ca(2+) (o) (0.5 mM). Up-regulation of these mRNAs by elevated Ca(2+) (o) was confirmed by quantitative PCR. Elevated Ca(2+) (o) stimulated secretion of CXCL10 and MCP-3 but not CXCL9 in GT1-7 cells, and this effect was mediated by an extracellular calcium-sensing receptor (CaR) as the dominant negative CaR attenuated secretion of CXCL10 and MCP-3. CXCL10 and MCP-3 were localized in mouse GnRH neurons in the preoptic hypothalamus. Suppression of K(+) channels (BK channels) with 25 nM charybdotoxin inhibited high-Ca(2+) (o)-stimulated CXCL10 release. Accordingly, CaR activation by a specific CaR agonist, NPS-467, resulted in the activation of a Ca(2+)-activated K(+) channel in these cells. CaR-mediated MCP-3 secretion involves the PI3 kinase pathway in GT1-7 cells. MCP-3 stimulated chemotaxis of astrocytes treated with transforming growth factor-beta (TGFbeta). With TGFbeta-treated astrocytes, we next observed that conditioned medium from GT1-7 cells treated with high Ca(2+) promoted chemotaxis of astrocytes, and this effect was attenuated by a neutralizing antibody to MCP-3. These results implicate CaR as an important regulator of GnRH neuron function in vivo by stimulating secretion of heretofore unsuspected cytokines, i.e., CXCL10 and MCP-3.

Early cutaneous gene transcription changes in adult atopic dermatitis and potential clinical implications

Atopic dermatitis (AD) is a common pruritic dermatitis with macroscopically non-lesional skin that is often abnormal. Therefore, we used high-density oligonucleotide arrays to identify cutaneous gene transcription changes associated with early AD inflammation as potential disease control targets. Skin biopsy specimens analysed included normal skin from five healthy non-atopic adults and both minimally lesional skin and nearby or contralateral non-lesional skin from six adult AD patients. Data were analysed on an individual gene basis and to identify biologically relevant gene networks. Transcription levels of selected genes were also analysed by quantitative PCR. Differential transcription occurring early in AD skin was indicated for (i) individual genes such as C-C chemokine ligand (CCL)18, CCL13, and interferon-alpha2 (IFNalpha2), (ii) genes associated with peroxisome proliferator-activated receptor (PPAR)alpha- and PPARgamma-regulated transcription, and possibly for (iii) immunoglobulin J-chain and heavy chain isotype transcripts. These data suggest that local changes in immunoglobulin-associated transcription may favour IgE over secretory immunoglobulin (multimeric IgM and IgA) expression in AD skin. Decreased PPAR activity appears common to both AD and psoriasis, and reduced cutaneous IFNalpha2 transcription also appears characteristic of AD. Identification of these genes and pathways will direct future research towards controlling AD.

Hypertonic saline and pentoxifylline reduces hemorrhagic shock resuscitation-induced pulmonary inflammation through attenuation of neutrophil degranulation and proinflammatory mediator synthesis

BACKGROUND

Ringer's lactate (RL), the current standard resuscitation fluid, potentiates neutrophil activation and is associated with pulmonary inflammation. Resuscitation with hypertonic saline and pentoxifylline (HSPTX) has been shown to attenuate hemorrhagic shock-induced injury when compared with RL. Because the neutrophil plays a major role in postshock inflammation, we hypothesized that HSPTX reduces pulmonary inflammation after resuscitation in comparison to RL.

METHODS

Sprague-Dawley rats underwent controlled shock and were resuscitated with RL (32 mL/kg) or HSPTX (4 mL/kg 7.5% NaCl + pentoxifylline 25 mg/kg). Animals who did not undergo shock or resuscitation served as controls. After 24 hours, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. Cytokine induced neutrophil chemoattractant (CINC) was measured in BALF by enzyme-linked immunosorbent assay. Matrix metalloproteinases (MMP)-2 and -9 were measured by zymography. Hemeoxygenase-1 (HO-1) was assessed by Western blot and immunohistochemistry.

RESULTS

HSPTX resuscitation led to a 62% decrease in CINC levels compared with RL (p < 0.01). BALF MMP-2 expression was attenuated by 11% with HSPTX (p = 0.09). Lung MMP-2 and MMP-9 expression was reduced by 89% (p < 0.01) and 76%, respectively (p < 0.05). Lung HO-1 expression declined by 34% with HSPTX in comparison to RL (p < 0.01), indicating less oxidative injury. Lung immunohistochemistry localized HO-1 to neutrophils, macrophages, and airway epithelial cells.

CONCLUSION

Collectively, the attenuation of pulmonary inflammation with HSPTX after shock when compared with RL is associated with downregulation of neutrophil activation, oxidative stress, and proinflammatory mediator production.

Immune cell recruitment following acoustic trauma

Acoustic trauma induces cochlear inflammation. We hypothesized that chemokines are involved in the recruitment of leukocytes as part of a wound healing response. The cochleas of NIH-Swiss mice, exposed to octave-band noise (8-16 kHz, at 118 dB) for 2h, were examined after the termination of exposure. Leukocytes were identified immunohistochemically with antibodies to CD45 and F4/80. Gene array analysis followed by RT-PCR was performed on cochlear tissue to identify up-regulation of chemokine and adhesion molecule mRNA. The expression of the adhesion molecule ICAM-1 was also investigated immunohistochemically. Few CD45- or F4/80-positive leukocytes were observed in the non-exposed cochlea. Following acoustic trauma however, the number of CD45-positive cells was dramatically increased especially after 2 and 4 days, after which time the numbers decreased. F4/80-positive cells also increased in number over the course of a week. Gene array analysis indicated increased expression of monocyte chemoattractant protein 5 (MCP-5), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein-1beta (MIP-1beta) and ICAM-1. RT-PCR, performed using primers for the individual mRNA sequences, confirmed the increased expression of MCP-1, MCP-5, MIP-1beta, and ICAM-1 relative to non-exposed mice. In the normal cochlea, ICAM-1 immunohistochemical expression was observed in venules, spiral ligament fibrocytes and in endosteal cells of the scala tympani. Expression increased to include more of the spiral ligament and endosteal cells after acoustic trauma. A cochlear inflammatory response is initiated in response to acoustic trauma and involves the recruitment of circulating leukocytes to the inner ear.

Secretion of functional monocyte chemotactic protein 3 by recombinant Mycobacterium bovis BCG attenuates vaccine virulence and maintains protective efficacy against M. tuberculosis infection

A strain of Mycobacterium bovis BCG that secretes high levels of functional murine monocyte chemotactic protein 3 (BCG(MCP-3)) was developed. Mice vaccinated with BCG(MCP-3) displayed increased lymphocyte migration in vivo and augmented antigen-specific T-cell responses compared to mice vaccinated with BCG alone. The level of protection afforded by BCG(MCP-3) was equivalent to that with control BCG; however, immunodeficient mice infected with BCG(MCP-3) survived significantly longer than mice infected with the control BCG strain. Therefore, BCG(MCP-3) may be a safer alternative than conventional BCG for vaccination of immunocompromised individuals.

Treatment with an oral small molecule inhibitor of P selectin (PSI-697) decreases vein wall injury in a rat stenosis model of venous thrombosis

BACKGROUND

Vein wall injury after thrombosis is multifactorial but seems dependent on thrombus and local thrombotic and inflammatory mechanisms. We hypothesized that inhibition of vein wall injury through reduction of thrombotic and inflammatory events with P-selectin inhibition and/or low-molecular-weight heparin (LMWH) occurs independently of thrombus resolution in a rat model of venous thrombosis.

METHODS

Male rats underwent inferior vena cava (IVC) stenosis (94.4% +/- 0.5% reduction in IVC diameter) to induce thrombosis. Rats were treated from 2 days after thrombosis until they were killed 7 days later. Groups consisted of (1) PSI-697, a P-selectin inhibitor (30 mg/kg; oral gavage daily); (2) LMWH-Lovenox (LOV; enoxaparin) 3 mg/kg subcutaneously daily; (3) PSI-697 (30 mg/kg; oral gavage daily) plus LOV 3 mg/kg subcutaneously daily (PSI + LOV); (4) and untreated controls. Evaluations included thrombus mass, vein wall tensiometry (stiffness [inverse of compliance]), intimal thickness scoring by light microscopy, vein wall inflammatory mediators by enzyme-linked immunosorbent assay, and vein wall inflammatory cells by histologic evaluation.

RESULTS

Thrombus mass was not reduced by any treatment. Animals treated with PSI-697 alone, LOV alone, or PSI + LOV demonstrated significant decreases in vein wall stiffness when compared with controls. The vein wall stiffness of the PSI-697-treated groups was also significantly lower than in the LOV-only group. Animals treated with PSI-697 showed a significantly decreased intimal thickness score when compared with vehicle control IVCs. Vein wall intimal thickening was also significantly decreased in animals treated with PSI-697 vs LOV. The PSI-697 and PSI + LOV groups manifested significant decreases in the immunoregulatory and inflammatory cytokine interleukin 13 as compared with controls and LOV. Vein wall monocyte chemotactic protein 1 levels were also significantly reduced in the PSI-697 and PSI + LOV groups vs control. Only PSI-697 significantly decreased vein wall levels of platelet-derived growth factor betabeta. Both the LOV and PSI + LOV groups had significant increases in vein wall monocytes and total inflammatory cells vs controls.

CONCLUSIONS

These data suggest that both LMWH and PSI-697 inhibit vein wall injury independently of thrombus mass. P-selectin inhibition seemed superior to LMWH in measured parameters of injury and mediator inhibition.

IL-1beta disrupts postnatal lung morphogenesis in the mouse

Pulmonary inflammation and increased production of the inflammatory cytokine IL-1beta are associated with the development of bronchopulmonary dysplasia (BPD) in premature infants. To study the actions of IL-1beta in the fetal and newborn lung in vivo, we developed a bitransgenic mouse in which IL-1beta is expressed under conditional control in airway epithelial cells. Perinatal pulmonary expression of IL-1beta caused respiratory insufficiency that was associated with increased postnatal mortality. While intrauterine growth of IL-1beta-expressing mice was normal, their postnatal growth was impaired. IL-1beta disrupted alveolar septation and caused abnormalities in alpha-smooth muscle actin and elastin deposition in the septa of distal airspaces. IL-1beta disturbed capillary development and inhibited the production of vascular endothelial growth factor in the lungs of infant mice. IL-1beta induced the expression of CXC chemokines KC (CXCL1) and macrophage inflammatory protein-2 (CXCL2) and of CC chemokines monocyte chemotactic protein (MCP)-1 (CCL2) and MCP-3 (CCL7), consistent with neutrophilic and monocytic infiltration of the lungs. IL-1beta caused goblet cell metaplasia and bronchial smooth muscle hyperplasia. Perinatal expression of IL-1beta in epithelial cells of the lung caused a lung disease that was clinically and histologically similar to BPD.

Increased expression of Th2-associated chemokines in bullous pemphigoid disease. Role of eosinophils in the production and release of these chemokines

Bullous pemphigoid is an inflammatory disease of the skin associated with eosinophil infiltration and the presence of high levels of Th2 cytokines in the associated blister fluid. Little is known about the contribution of chemokines in this disease. We found that eotaxin and MCP-4 mRNA and immunoreactivity were expressed in all biopsies of BP patients and were mainly localized to the epidermis and eosinophils. The expression of eotaxin and MCP-4 was enhanced in eosinophils following IL-5 treatment. Subsequent stimulation of IL-5-primed eosinophils with Ig-immune complexes, results in increase secretion of eotaxin and MCP-4 in the supernatants. Using immunostaining, these two chemokines were localized to the granules of eosinophils. BF was found to contain chemotactic activity for eosinophils, neutrophils and T cells. The chemotactic effect of BF for eosinophils was more effective when eosinophils were stimulated with IL-5 or IL-4. We also found that the levels of Th(2)-associated chemokines (eotaxin and MCP-4) in BF were significantly higher than the Th(1)-associated chemokines (MIP-1beta and IP-10). This was consistent with the increased chemotaxis of polarized Th(2) cells toward BF, when compared to Th(1)-differentiated T cells. Our results support the involvement of Th(2)-associated chemokines in the pathogenesis of BP disease.

Elevated serum monocyte chemoattractant protein-4 and chronic inflammation in overweight subjects

OBJECTIVE

Chronic inflammation observed in obesity has been reported to be implicated in the development of atherosclerosis. We screened candidate chemokines that link chronic inflammation and obesity.

RESEARCH METHODS AND PROCEDURES

Japanese overweight (n = 39, BMI 28.7 +/- 0.65 kg/m(2)) and normal-weight (n = 24, BMI 22.3 +/- 0.45 kg/m(2)) subjects were enrolled. Using antibody-based protein microarray, spot intensities of monocyte chemoattractant protein (MCP)-4, eotaxin, and eotaxin-2 correlated with anthropometric parameters. We further measured serum concentration of these chemokines and mRNA levels in adipose tissues obtained from volunteers.

RESULTS

Serum MCP-4 levels showed positive correlation with BMI (r = 0.318, p = 0.014), waist (r = 0.316, p = 0.018), and waist-to-hip ratio (WHR) (r = 0.264, p = 0.049). Furthermore, MCP-4 correlated with homeostasis model assessment of insulin resistance (r = 0.392, p = 0.002), high-sensitivity C-reactive protein (hsCRP) (r = 0.350, p = 0.006). In step-wise multiple regression analyses, hsCRP independently correlated with MCP-4 levels. The expression of MCP-4 mRNA in visceral adipose tissue positively correlates with BMI. Serum eotaxin levels correlate with BMI (r = 0.262, p = 0.045) and WHR (r = 0.383, p = 0.003). Serum eotaxin-2 levels correlated with BMI (r = 0.464, p < 0.001), waist (r = 0.333, p = 0.017), and WHR (r = 0.278, p = 0.048). However, eotaxin and eotaxin-2 levels did not show significant correlation with hsCRP.

DISCUSSION

Serum levels of MCP-4, eotaxin, and eotaxin-2, which belong to CC chemokine family and share CC chemokine receptor 3, correlated with BMI. These chemokines, especially MCP-4, may be critical molecules that link obesity and chronic inflammation.

Factors contributing to nasal allergic late phase eosinophilia

OBJECTIVE

This study focused on factors contributing to eosinophilia after intranasal allergen challenge.

METHODS

Nasal secretions of 13 allergic individuals were gained over a period of 8 hours after nasal allergen challenge. Early and late phase reactions were determined by acoustic rhinometry and changes of volume and total protein in nasal secretions. Eosinophilia was demonstrated by nasal eosinophilic cationic protein. Interleukin (IL)-5; the chemokines IL-8, monocyte chemotactic protein (MCP)-1 and MCP-3, and eotaxin; soluble vascular cell adhesion molecule 1 (sVCAM-1); and the leukotriene C4 (LTC4) were analyzed by enzyme-linked immunosorbent assay for their suggested impacts on tissue eosinophilia.

RESULTS

By means of rhinometry, we observed in 69% an alternating type of late phase response, followed by a bilateral (15%) or unilateral (8%) type. A biphasic kinetic could be demonstrated by changes in nasal volume and total protein of nasal secretions, reflecting the early and late phase responses. A typical late phase kinetic was observed for IL-5, MCP-1, eotaxin, sVCAM-1, and LTC4. Interleukin 8 was characteristic for early phase reaction but increased in late phase as well. We could not detect any MCP-3 in our samples.

CONCLUSIONS

Our data point to a relevant role of the T(H)2 cytokine IL-5; of the chemokines IL-8, MCP-1, and eotaxin; of the adhesion molecule sVCAM-1; and of the leukotriene LTC4 for the allergic late phase eosinophilia.

Human endotoxemia induces down-regulation of monocyte CC chemokine receptor 2

Upon injection of Escherichia coli lipopolysaccharide into human volunteers, the monocyte density of CC chemokine receptor 2 (CCR2) decreased. Minimal CCR2 density was observed 4 h after injection. Peak plasma concentrations of the CCR2 ligand monocyte chemotactic protein 1 and of tumor necrosis factor alpha were reached after 4 h and 2 h, respectively.

Nuclear factor-kappaB affects tumor progression in a mouse model of malignant pleural effusion

We developed a novel mouse model of malignant pleural effusion (MPE) by injecting Lewis lung cancer (LLC) cells directly into the pleural space of syngeneic C57B/6 mice. The pleural effusions in this model share common cellular and biochemical features with human MPEs. Implantation and growth of pleural tumors triggers a host inflammatory response characterized by a mixed inflammatory cell influx into the pleural fluid. LLC cells exhibited high basal nuclear factor (NF)-kappaB activity in vitro and in vivo, which we used to drive expression of a NF-kappaB-dependent green fluorescent protein-firefly luciferase fusion reporter construct. NF-kappaB-dependent reporter expression allowed intravital tracing of pleural tumors. Inhibition of NF-kappaB in LLC cells did not affect cell viability in culture; however, injection of LLC cells expressing a dominant NF-kappaB inhibitor resulted in decreased tumor burden, decreased pleural effusion volume, and decreased pleural effusion TNF-alpha levels. These studies indicate that tumor NF-kappaB activity regulates pleural tumor progression. This reproducible model of MPE can be used to further study the influence of specific host and tumor factors on the pathogenesis of MPE and evaluate new therapeutic strategies.

The chemokines, CX3CL1, CCL14, and CCL4, promote human trophoblast migration at the feto-maternal interface

Human embryo implantation is a complex process involving blastocyst attachment to the endometrial epithelium and subsequent trophoblast invasion of the decidua. Chemokines, critical regulators of leukocyte migration, are abundant in endometrial epithelial and decidual cells at this time. We hypothesized that endometrial chemokines stimulate trophoblast invasion. Chemokine receptors CX3CR1 and CCR1 were immunolocalized in human first-trimester implantation sites, specifically to endovascular extravillous trophoblasts, but not to the invading interstitial EVTs (iEVTs), with weak staining also on syncytium. CCR3 was localized to invading iEVTs and to microvilli on the syncytial surface. Expression of CX3CL1 (fractalkine), CCL7 (MCP-3), and their receptors (CX3CR1, CCR1, CCR2, CCR3, and CCR5) mRNA was examined in cellular components of the maternal-embryonic interface by RT-PCR. Both chemokines were abundant in entire endometrium and placenta, endometrial cells (primary cultures and HES, a human endometrial epithelial cell line) and trophoblast cell lines (JEG-3, ACIM-88, and ACIM-32). Chemokine receptor mRNA was expressed by placenta and trophoblast cell lines: CCR1 by all trophoblast cell types, whereas CCR2, CCR3, and CX3CR1 were more variable. CX3CR1, CCR1, CCR2, and CCR5 were also expressed by endometrial cells. Migration assays used the trophoblast cell line most closely resembling extravillous cytotrophoblast (AC1M-88). Trophoblast migration occurred in response to CX3CL1, CCL14, and CCL4, but not CCL7. Endometrial cell-conditioned media also stimulated trophoblast migration; this was attenuated by neutralizing antibodies to CX3CL1 and CCL4. Thus, chemokines are expressed by maternal and embryonic cells during implantation, whereas corresponding receptors are on trophoblast cells. Promotion of trophoblast migration by chemokines and endometrial cell conditioned medium indicates an important involvement of chemokines in maternal-fetal communication.

CCR3 expression and function in asthmatic airway smooth muscle cells

Asthma is characterized by an increase in airway smooth muscle mass and a decreased distance between the smooth muscle layer and the epithelium. Furthermore, there is evidence to indicate that airway smooth muscle cells (ASMC) express a wide variety of receptors involved in the immune response. The aims of this study were to examine the expression of CCR3 on ASMC, to compare this expression between asthmatic and nonasthmatic subjects, and to determine the implications of CCR3 expression in the migration of ASMC. We first demonstrated that ASMC constitutively express CCR3 at both mRNA and protein levels. Interestingly, TNF-alpha increases ASMC surface expression of CCR3 from 33 to 74%. Furthermore, using FACS analysis, we found that ASMC CCR3 is expressed to a greater degree in asthmatic vs control subjects (95 vs 75%). Functionality of the receptor was demonstrated by calcium assay; the addition of CCR3 ligand eotaxin to ASMC resulted in an increase in intracellular calcium production. Interestingly, ASMC was seen to demonstrate a positive chemotactic response to eotaxin. Indeed, ASMC significantly migrated toward 100 ng/ml eotaxin (2.2-fold increase, compared with control). In conclusion, the expression of CCR3 by ASMC is increased in asthmatics, and our data show that a CCR3 ligand such as eotaxin induces migration of ASMC in vitro. These results may suggest that eotaxin could be involved in the increased smooth muscle mass observed in asthmatics through the activation of CCR3.

The evolution of isolated bilateral lung contusion from blunt chest trauma in rats: cellular and cytokine responses

Lung contusion is the leading cause of death from blunt thoracic trauma in adults, but its mechanistic pathophysiology remains unclear. This study uses a recently developed rat model to investigate the evolution of inflammation and injury in isolated lung contusion. Bilateral lung contusion with minimal cardiac trauma was induced in 54 anesthetized rats by dropping a 0.3-kg hollow cylindrical weight onto a precordial shield (impact energy, 2.45 Joules). Arterial oxygenation, pressure-volume (P-V) mechanics, histology, and levels of erythrocytes, leukocytes, albumin, and inflammatory mediators in bronchoalveolar lavage (BAL) were assessed at 8 min, at 4, 12, 24, and 48 h, and at 7 days after injury. The role of neutrophils in the evolution of inflammatory injury was also specifically studied by depleting these cells with intravenous vinblastine before lung contusion. Arterial oxygenation was severely reduced at 8 min to 24 h postcontusion, but became almost normal by 48 h. Levels of erythrocytes, leukocytes, and albumin in BAL were increased at <or=24 h, and returned toward normal by 48 h. Deficits in P-V mechanics were most apparent at 24 h postcontusion. Levels of macrophage inflammatory polypeptide-2, cytokine-induced neutrophil chemoattractant-1, and interleukin 6 in BAL peaked at 24 h, whereas monocyte chemoattractant protein-1 and interleukin 1beta peaked at 24 to 48 h postcontusion. Histology showed early hemorrhagic injury (8 min-12 h), with neutrophilic infiltration at 24 h and areas of bronchiolitis obliterans organizing pneumonia-associated fibrosis at 7 days. Vinblastine-treated neutropenic rats had significantly reduced lung injury based on total lung volume at 4 h and on BAL albumin levels at 24 h postcontusion. Inflammatory injury from isolated bilateral lung contusion in rats is most severe in the acute period (8 min-24 h) after initial blunt trauma, and includes a component of neutrophil-dependent pathology.

Salmonella pathogenicity island 2-dependent expression of suppressor of cytokine signaling 3 in macrophages

Salmonella pathogenicity island 2 (SPI-2), which is located at centisome 30.7 on the chromosome of Salmonella enterica serovar Typhimurium, is required for growth within macrophages and systemic infection in mice. We recently reported that the infection of macrophages with Salmonella induces the expression of cyclooxygenase-2 in a manner dependent on SPI-2. In the present study, gene expression analysis using a cDNA array further showed the involvement of SPI-2 in the expression of suppressor of cytokine signaling 3 (SOCS-3), which is involved in the inhibition of cytokine signaling via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. A high level of SOCS-3 expression was induced in J774 macrophages infected with wild-type Salmonella compared to that in macrophages infected with a strain carrying a mutation in the spiC gene within SPI-2. Other members of the SOCS family were not detected in Salmonella-infected macrophages. The SPI-2-induced up-regulation of SOCS-3 expression was dependent on activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. Furthermore, the inhibition of gamma-interferon-induced STAT-1 and interleukin-6-induced STAT-3 tyrosine phosphorylation correlated with the expression of SOCS-3. Taken together, these results indicate that Salmonella causes SPI-2-dependent activation of ERK1/2, leading to SOCS-3 expression, which in turn inhibits cytokine signaling via the JAK/STAT pathway.

Loss of histochemical identity in mast cells lacking carboxypeptidase A

Mast cell carboxypeptidase A (Mc-cpa) is a highly conserved secretory granule protease. The onset of expression in mast cell progenitors and lineage specificity suggest an important role for Mc-cpa in mast cells. To address the function of Mc-cpa, we generated Mc-cpa-null mice. Mc-cpa-/- mast cells lacked carboxypeptidase activity, revealing that Mc-cpa is a nonredundant enzyme. While Mc-cpa-/- peritoneal mast cells were ultrastructurally normal and synthesized normal amounts of heparin, they displayed striking histochemical and biochemical hallmarks of immature mast cells. Wild-type peritoneal mast cells had a mature phenotype characterized by differential histochemical staining with proteoglycan-reactive dyes (cells do not stain with alcian blue but stain with safranin and with berberine) and a high side scatter to forward scatter ratio by flow cytometry and were detergent resistant. In contrast, Mc-cpa-/- peritoneal mast cells, like immature bone marrow-derived cultured mast cells, stained with alcian blue normally or weakly and either did not stain with safranin and berberine or stained weakly, had a low side scatter to forward scatter ratio, and were detergent sensitive. This phenotype was partially ameliorated with age. Thus, histochemistry and flow cytometry, commonly used to measure mast cell maturation, deviated from morphology in Mc-cpa-/- mice. The Mc-cpa-/- mast cell phenotype was not associated with defects in degranulation in vitro or passive cutaneous anaphylaxis in vivo. Collectively, Mc-cpa plays a crucial role for the generation of phenotypically mature mast cells.

Cloning and functional characterization of the rabbit C-C chemokine receptor 2

BACKGROUND

CC-family chemokine receptor 2 (CCR2) is implicated in the trafficking of blood-borne monocytes to sites of inflammation and is implicated in the pathogenesis of several inflammatory diseases such as rheumatoid arthritis, multiple sclerosis and atherosclerosis. The major challenge in the development of small molecule chemokine receptor antagonists is the lack of cross-species activity to the receptor in the preclinical species. Rabbit models have been widely used to study the role of various inflammatory molecules in the development of inflammatory processes. Therefore, in this study, we report the cloning and characterization of rabbit CCR2. Data regarding the activity of the CCR2 antagonist will provide valuable tools to perform toxicology and efficacy studies in the rabbit model.

RESULTS

Sequence alignment indicated that rabbit CCR2 shares 80 % identity to human CCR2b. Tissue distribution indicated that rabbit CCR2 is abundantly expressed in spleen and lung. Recombinant rabbit CCR2 expressed as stable transfectants in U-937 cells binds radiolabeled 125I-mouse JE (murine MCP-1) with a calculated Kd of 0.1 nM. In competition binding assays, binding of radiolabeled mouse JE to rabbit CCR2 is differentially competed by human MCP-1, -2, -3 and -4, but not by RANTES, MIP-1alpha or MIP-1beta. U-937/rabbit CCR2 stable transfectants undergo chemotaxis in response to both human MCP-1 and mouse JE with potencies comparable to those reported for human CCR2b. Finally, TAK-779, a dual CCR2/CCR5 antagonist effectively inhibits the binding of 125I-mouse JE (IC50 = 2.3 nM) to rabbit CCR2 and effectively blocks CCR2-mediated chemotaxis.

CONCLUSION

In this study, we report the cloning of rabbit CCR2 and demonstrate that this receptor is a functional chemotactic receptor for MCP-1.

A Non-Glycosaminoglycan-Binding Variant of CC Chemokine Ligand 7 (Monocyte Chemoattractant Protein-3) Antagonizes Chemokine-Mediated Inflammation

A non-glycosaminoglycan (GAG)-binding variant of the pleiotropic chemokine CCL7 was generated by mutating to alanine the basic (B) amino acids within an identified (44)BXBXXB(49) GAG-binding motif. Unlike wild-type (wt) CCL7, the mutant sequence had no affinity for heparin. However, the mutant retained a normal affinity for CCR1, CCR2b, and CCR3, and produced a normal calcium flux in mononuclear leukocytes. Both the wt and mutant proteins elicited an equal leukocyte chemotactic response within a solute diffusion gradient but, unlike the wt protein, the mutant failed to stimulate cell migration across a model endothelium. The number of leukocytes recruited to murine air pouches by the mutant sequence was lower than that recruited by wt CCL7. Furthermore, the presence of a mixture of a mutant and wt CCL7 within the air pouch elicited no significant cell accumulation. Cell recruitment also failed using a receptor-sharing mixture of mutant CCL7 and wt CCL5 or a nonreceptor sharing mixture of mutant CCL7 and wt CXCL12. The potential of the mutant sequence to modulate inflammation was confirmed by demonstration of its ability to inhibit the chemotactic response generated in vitro by synovial fluid from patients with active rheumatoid arthritis. A further series of experiments suggested that the non-GAG-binding mutant protein could potentially induce receptor desensitization before, and at a site remote from, any physiological recognition of GAG-bound chemokines. These data demonstrate that GAG binding is required for chemokine-driven inflammation in vivo and also suggest that a non-GAG-binding chemokine receptor agonist can inhibit the normal vectorial leukocyte migration mediated by chemokines.

Elevated ex vivo monocyte chemotactic protein-1 (CCL2) in pulmonary as compared with extra-pulmonary tuberculosis

Background

Tuberculosis causes 3 million deaths annually. The most common site of tuberculosis is pulmonary however; extra-pulmonary forms of the disease also remain prevalent. Restriction of Mycobacterium tuberculosis depends on effective recruitment and subsequent activation of T lymphocytes, mononuclear and polymorphonuclear cells to the site of infection. Tumor necrosis factor (TNF)-α is essential for granuloma formation and is a potent activator of monocyte chemotactic protein (MCP-1, CCL2). CCL2 is essential for recruitment of monocytes and T cells and has been shown to play a role in protection against tuberculosis. Interleukin -8 (CXCL8) is a potent activator of neutrophils. Increased levels of CCL2, CXCL8 and TNFα are reported in tuberculosis but their significance in different forms of tuberculosis is as yet unclear. We have used an ex vivo assay to investigate differences in immune parameters in patients with either pulmonary or extra-pulmonary tuberculosis.

Methods

Serum levels of CCL2, CXCL8 and TNFα were measured in patients with pulmonary tuberculosis (N = 12), extra-pulmonary tuberculosis (N = 8) and BCG-vaccinated healthy volunteers (N = 12). Whole blood cells were stimulated with non-pathogenic Mycobacterium bovis bacille-Calmette Guerin (BCG) vaccine strain or bacterial lipopolysaccharide (LPS) and cyto/chemokines were monitored in supernatants.

Results

Circulating serum levels of CXCL8 and TNFα were raised in all tuberculosis patients, while CCL2 levels were not. There was no difference in spontaneous cytokine secretion from whole blood cells between patients and controls. M. bovis BCG-induced ex vivo CCL2 secretion was significantly greater in pulmonary as compared with both extra-pulmonary tuberculosis patients and endemic controls. In response to LPS stimulation, patients with pulmonary tuberculosis showed increased CCL2 and TNFα responses as compared with the extra-pulmonary group. BCG-, and LPS-induced CXCL8 secretion was comparable between patients and controls.

Conclusion

CCL2 is activated by TNFα and is essential for recruitment of monocytes and T cells to the site of mycobacterial infection. Increased CCL2 activation in pulmonary tuberculosis may result in a stronger cellular response as compared with extra-pulmonary tuberculosis patients, and this may contribute to the localization of infection to the pulmonary site.

Neutrophil-derived heparin-binding protein (HBP/CAP37) deposited on endothelium enhances monocyte arrest under flow conditions

In acute inflammation, infiltration of neutrophils often precedes a second phase of monocyte invasion, and data in the literature suggest that neutrophils may directly stimulate mobilization of monocytes via neutrophil granule proteins. In this study, we present a role for neutrophil-derived heparin-binding protein (HBP) in monocyte arrest on endothelium. Adhesion of neutrophils to bovine aorta endothelial cells (ECs) or HUVEC-triggered secretion of HBP and binding of the protein to the EC surface. Blockade of neutrophil adhesion by treatment with a mAb to CD18 greatly reduced accumulation of HBP. In a flow chamber model, immobilized recombinant HBP induced arrest of human monocytes or monocytic Mono Mac 6 (MM6) cells to activated EC or plates coated with recombinant adhesion molecules (E-selectin, P-selectin, VCAM-1). However, immobilized recombinant HBP did not influence arrest of neutrophils or lymphocytes. Treatment of MM6 cells with recombinant HBP evoked a rapid and clear-cut increase in cytosolic free Ca(2+) that was found to be critical for the HBP-induced monocyte arrest inasmuch as pretreatment with the intracellular calcium chelating agent BAPTA-AM abolished the evoked increase in adhesion. Thus, secretion of a neutrophil granule protein, accumulating on the EC surface and promoting arrest of monocytes, could contribute to the recruitment of monocytes at inflammatory loci.

Chemokine expression is dysregulated in the endometrium of women using progestin-only contraceptives and correlates to elevated recruitment of distinct leukocyte populations

BACKGROUND

Breakthrough bleeding (BTB) is the most common reason for discontinuation of progestin-only (p-only) contraceptives, yet the causes are unknown. Use of p-only contraceptives is associated with elevated influx of endometrial leukocytes, similar to that observed perimenstrually or within decidualized endometrium. We hypothesized that chemokine expression is altered in women using p-only contraceptives, leading to abnormal leukocyte recruitment and BTB.

METHODS

Expression of eight highly abundant endometrial chemokines was examined using immunohistochemistry and real-time PCR, in endometria from women using subdermal and intrauterine levonorgestrel and correlated to leukocyte subpopulations.

RESULTS

Macrophage-derived chemokine (MDC), hemofiltrate CC chemokine-1 (HCC-1), monocyte chemoattractant protein-3 (MCP-3), interleukin-8 (IL-8) and eotaxin were strongly produced by epithelial glands, comparable to levels in premenstrual phase endometrium. Stromal cells were negative for chemokines in atrophic/shedding endometria, but intensely positive in highly decidualized tissues for MDC, MCP-3, HCC-1 and 6Ckine. Macrophage inflammatory protein-1beta (MIP-1b) and HCC-4 were suppressed in all p-exposed endometria.

CONCLUSIONS

These data demonstrate that chemokine expression is dysregulated in p-exposed endometria, consistent with the morphological appearance of the endometrium and the leukocyte subsets present. This reinforces a potential role for chemokines in the elevated leukocyte recruitment that contributes to endometrial fragility and BTB.

Monocyte chemotactic protein-2 and -3 in amniotic fluid: relationship to microbial invasion of the amniotic cavity, intra-amniotic inflammation and preterm delivery

OBJECTIVE

To evaluate the presence of monocyte chemotactic protein (MCP)-2 and MCP-3 in cervical and amniotic fluid in women in preterm labor.

STUDY DESIGN

Cervical and amniotic fluid was sampled from women with singleton pregnancies (< or =34 weeks) in preterm labor (n = 58).

RESULTS

Monocyte chemotactic protein-2 (range: 80-583 pg/ml) and MCP-3 (range: 36-649 pg/ml) were detectable in 7/58 women in preterm labor. Monocyte chemotactic protein-3 was found significantly more often in amniotic fluid of women delivered within 7 days (P < 0.001), <34 weeks (P = 0.002), or with intra-amniotic inflammation (P < 0.001) and microbial invasion of the amniotic fluid (P = 0.003). Women in preterm labor had detectable levels of MCP-2 significantly more often if they gave birth before 34 weeks of gestation (P = 0.038) or had intra-amniotic inflammation (P = 0.042).

CONCLUSIONS

The presence of MCPs in amniotic fluid of women in preterm labor was associated with preterm birth before 34 weeks of gestation (MCP-2 and MCP-3), microbial invasion (MCP-3), and inflammation (MCP-2 and MCP-3) of the amniotic cavity.

The carboxyl terminus of the chemokine receptor CCR3 contains distinct domains which regulate chemotactic signaling and receptor down-regulation in a ligand-dependent manner

The chemokine receptor CCR3 regulates the chemotaxis of leukocytes implicated in allergic disease, such as eosinophils. Incubation of eosinophils with CCL11, CCL13 or CCL5 resulted in a rapid decrease of cell-surface CCR3 which was replicated using CCR3 transfectants. Progressive truncation of the CCR3 C terminus by 15 amino acids produced three constructs, Delta340, Delta325 and Delta310. Delta340 and Delta325 were able to bind CCL11 with affinities similar to wild-type CCR3. Delta340 transfectants exhibited enhanced migration and reduced receptor down-regulation in response to CCL11 and CCL13. Delta325 transfectants displayed chemotactic responses to CCL11 and CCL13 similar to wild-type CCR3, and had impaired down-regulation when stimulated with CCL13 but not CCL11. In contrast, neither the Delta325 nor Delta340 truncation affected chemotaxis or receptor down-regulation induced by CCL5. Delta310 transfectants bound CCL11 poorly and were biologically inactive. Inhibitors of p38 mitogen-activated protein kinase and PI3-kinase antagonized eosinophil shape change responses and chemotaxis of transfectants to CCL11 and CCL13. In contrast, shape change but not chemotaxis was sensitive to inhibition of the extracellular signal-regulated kinase kinase pathway suggesting differential regulation of the two responses. Thus, the CCR3 C terminus contains distinct domains responsible for the regulation of receptor desensitization and for coupling to chemotactic responses.

Neuroprotection with the CXCL8 inhibitor repertaxin in transient brain ischemia

Infiltration of polymorphonuclear neutrophils (PMNs) is thought to play a role in ischemic brain damage. The present study investigated the effect of repertaxin, a new noncompetitive allosteric inhibitor for the receptors of the inflammatory chemokine CXC ligand 8 (CXCL8)/interleukin-8 (IL-8), on PMN infiltration and tissue injury in rats. Cerebral ischemia was induced by permanent or transient occlusion of the middle cerebral artery and myeloperoxidase activity, a marker of PMN infiltration, and infarct volume were evaluated 24 h later. Repertaxin (15 mg/kg) was administered systemically at the time of ischemia and every 2 h for four times. In permanent ischemia repertaxin reduced PMN infiltration by 40% in the brain cortex but did not limit tissue damage. In transient ischemia (90-min ischemia followed by reperfusion), repertaxin inhibited PMN infiltration by 54% and gave 44% protection from tissue damage. Repertaxin had anti-inflammatory and neuroprotective effects also when given at reperfusion and even at 2 h of reperfusion. The protective effect of repertaxin did not interfere with brain levels of the chemokine. Since the PMN infiltration and its inhibition by repertaxin were comparable in the two models we conclude that reperfusion induces PMN activation, and inhibition of CXCL8 by repertaxin might be of pharmacological interest in transient ischemia.

TRAIL counteracts the proadhesive activity of inflammatory cytokines in endothelial cells by down-modulating CCL8 and CXCL10 chemokine expression and release

Exposure of endothelial cells to recombinant tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induced a modest (2-fold) increase of HL-60 cell adhesion as compared to TNF-α (40-fold) or interleukin 1β (IL-1β; 20-fold). However, pretreatment of endothelial cultures with TRAIL determined a significant reduction of the proadhesive activity induced by both TNF-α and IL-1β. Unexpectedly, the antiadhesive activity of TRAIL was not due to interference with the nuclear factor κB (NF-κB)-mediated up-regulation of surface intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin adhesion molecules in response to inflammatory cytokines. In searching for the molecular mechanism underlying this biologic activity of TRAIL, a cDNA microarray analysis was performed. TRAIL pretreatment variably down-modulated the mRNA steady-state levels of several TNF-α-induced chemokines, and, in particular, it abrogated the TNF-α-mediated up-regulation of CCL8 and CXCL10. Of note, the addition of optimal concentrations of recombinant CCL8 plus CXCL10 to endothelial cultures completely restored the proadhesive activity of TNF-α. Moreover, experiments performed with agonistic anti-TRAIL receptor antibodies demonstrated that both TRAIL-R1 and TRAIL-R2 contributed, although at different levels, to TRAIL-induced chemokine modulation. Taken together, our data suggest that TRAIL might play an important role in modulating leukocyte/endothelial cell adhesion by selectively down-regulating CCL8 and CXCL10 chemokines.

Hypoxia-reoxygenation-induced chemokine transcription is not prevented by preconditioning or intermittent hypoxia, in mice hepatocytes

Prolonged ischemia used in liver surgery and/or transplantation causes cellular damage resulting in apoptosis and necrosis. Ischemia-reperfusion (I/R) led Kupffer cells to pro-inflammatory cytokines secretion [tumor necrosis factor (TNF)-alpha, interleukin-1] which involve chemokines secretion by hepatocytes. These chemokines have neutrophil chemotactic properties and neutrophils are involved in the development of I/R-induced necrosis. The aim of this study was to specify the consequence of partial oxygen pressure variation on hepatocyte chemokines synthesis and to verify if intermittent hypoxia and/or preconditioning could decrease it. It was performed on primary cultured mice hepatocytes and Kupffer cells, subjected to continuous, intermittent hypoxia or preconditioning phases, mimicking surgical processes. The chemokine secretion was evaluated by RNase protection assay and enzyme-linked immunosorbent assay method. Only monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) mRNA formation were observed, especially after 1-h hypoxia followed by 10-h (for MCP-1) or 24-h reoxygenation (for MIP-2). In conclusion, TNF-alpha and coculture with Kupffer cells increased hepatocyte chemokines mRNA transcription, whereas surgical split up protocols (intermittent hypoxia and preconditioning) had no significant effect.

Elevated monocyte chemotactic proteins 1, 2, and 3 in pulmonary alveolar proteinosis are associated with chemokine receptor suppression

Pulmonary alveolar proteinosis (PAP) is a rare autoimmune lung disease characterized by abnormal surfactant accumulation within alveolar macrophages, and circulating auto-antibodies against granulocyte-macrophage colony stimulating factor (GM-CSF) resulting in functional GM-CSF deficiency. Monocyte/macrophage chemotactic protein-1 (MCP-1) is elevated in PAP, suggesting association with the pathophysiology. Because PAP has been associated with inflammatory pulmonary changes, we hypothesized that other MCP family chemokines would be present and that Chemokine Chemotaxis Receptor 2 (CCR2) would be elevated on PAP mononuclear cells. Here we show for the first time that MCP-2 and MCP-3, like MCP-1, are highly elevated in PAP. We also confirm that PAP alveolar macrophages and not epithelial cells produce MCP-1, and that MCP-1 from PAP lung has functional chemoattractant activity. Surprisingly, CCR2 expression is diminished in PAP lymphocytes and alveolar macrophages compared to controls. Further, MCP-1 from PAP lung suppresses CCR2 expression in vitro, suggesting that in PAP, MCP-1 participates in an autocrine regulatory network in vivo.

The splenic microenvironment is a source of proangiogenesis/inflammatory mediators accelerating the expansion of murine erythroleukemic cells

The stromal compartments of hematopoietic organs (eg, spleen) are known to influence the viability and growth of diseased hematopoietic progenitors. Here we have used Friend murine leukemia virus (F-MuLV)-induced erythroleukemia to investigate factors of the splenic microenvironment that may make it fertile for the expansion and survival of malignant erythroblasts. We found that splenectomized, erythroleukemic mice exhibited extended survival compared with age-matched sham controls. In vitro, the proliferation of primary erythroleukemic cells cocultured with leukemic-derived splenic adherent cells or their conditioned media was found to be significantly higher than that observed in cocultures with healthy-derived adherent splenic cells. Cytokine protein arrays revealed that F-MuLV-infected splenocytes secreted elevated levels of interleukin-6 (IL-6), vascular endothelial growth factor-A (VEGF-A), macrophage chemoattractant protein-5 (MCP-5), soluble tumor necrosis factor receptor-1 (sTNFR1), IL-12p70, tumor necrosis factor-alpha (TNF-alpha), and IL-2 over normal splenocytes. Medium supplemented with both VEGF-A and MCP-5 could sustain proliferation of primary erythroleukemic cells in vitro, and significant proliferative suppression was observed upon addition of neutralizing antibodies to either of these factors. Furthermore, in vivo administration of a neutralizing antibody to VEGF-A extended survival times of erythroleukemic mice in comparison with controls. These findings suggest that VEGF-A and MCP-5 are potentially pivotal paracrine mediators occurring within the diseased splenic microenvironment capable of promoting disease acceleration and expansion of erythroleukemic blasts.