RANTES Production Research Articles

Salbutamol Modulates the Balance of Th1 and Th2 Cytokines by Mononuclear Cells from Allergic Asthmatics

Background: There is evidence that excessive use of inhalational β₂-agonists induces the deterioration of asthma. Although the exact mechanism of this remains to be elucidated, overuse of β₂-agonists may impair the Th1/Th2 balance in asthmatic airways. The aim of the present study was to evaluate whether salbutamol, a representative inhalational β₂-agonist, modifies the production of Th1- and Th2-type cytokines by mononuclear cells separated from patients with asthma and healthy volunteers. Methods: Peripheral blood mononuclear cells (PBMCs) obtained from 8 healthy volunteers and 10 patients with mild persistent asthma allergic to house dust mites were treated with either salbutamol or medium alone. PBMCs were then stimulated with either medium alone, house dust mite (Dermatophagoides farina, Df) allergen or a combination of ionomycin plus phorbol 12-myristate 13-acetate ester (PMA). Concentrations of IFN-γ, IL-13, TNF-α and RANTES in the cell supernatants were measured using ELISA. Results: In PBMCs from healthy volunteers, salbutamol did not modify IFN-γ production, but increased the spontaneous production of IL-13. In contrast, salbutamol significantly inhibited the spontaneous and ionomycin- plus PMA-stimulated production of IFN-γ by PBMCs from asthmatics. Salbutamol significantly enhanced both spontaneous and Df-induced production of IL-13 by PBMCs from asthmatics. Salbutamol did not modify the production of TNF-α. Finally, salbutamol enhanced the production of RANTES induced by Df allergen in asthmatics. Conclusions: Salbutamol inhibits IFN-γ and enhances IL-13 production by PBMCs from asthmatics. These effects would promote a Th1/Th2 imbalance in the airways and may therefore contribute to the deterioration of asthma.

Regulation of Toll-like receptor-induced chemokine production in murine dendritic cells by mitogen-activated protein kinases

Production of chemokines in dendritic cells (DCs) may be crucial in modulating immune responses generated through Toll-like receptor (TLR)-mediated recognition of microbial products. We evaluated chemokine production in DCs induced by TLR agonists and investigated the role of signaling pathways. DCs were generated from mouse bone marrow cells cultured with Fms-like tyrosine kinase-3 ligand and stimulated with a wide array of individual TLR agonists or simultaneously with pairs of combinations. Production of monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-1 (MIP-1/CCL3) and regulated on activation, normal T cell expressed and secreted (RANTES/CCL5), were determined in cell culture supernatants by ELISA or cytokine cytometric bead array. Pharmacological inhibitors of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), nuclear factor- kappaB (NF- kB) and phosphatidylinositol 3-kinase (PI3K), were used to investigate the role of signaling pathways. TLR agonists induced significantly elevated MCP-1, RANTES, and MIP-1. Production of RANTES and MIP-1 was particularly prominent after stimulation of DCs with TLR3 (Poly(I:C)), and TLR7/8 (R848) or TLR9 (CpG ODN) agonists, respectively. However, down-modulation of chemokine production was observed in simultaneously TLR-stimulated DCs. A positive role was identified for NF- kB, PI3K and ERK, whereas JNK had a negative regulatory effect on chemokine production in DCs. Positive and negative regulatory roles for the p38 MAPK pathway were observed. Thus, chemokine levels differed and most notably there was down-modulation of chemokines in DCs stimulated with combined TLR agonists. Furthermore, analysis of signaling pathways revealed a role for MAPKs in positive and negative regulation of chemokine production in DCs. The chemokine response of DCs induced by TLR agonists appears complex and could have important implications for vaccine design.

Role of chemokine and cytokine polymorphisms in the progression of HIV-1 disease

Allelic variants of the genes for chemokine receptors and their natural ligands, the chemokines, and cytokines can affect HIV-1 disease progression. This study investigates the level of expression of the CCR5-Δ32, CCR2b-641, RANTES In1.1C, SDF-1 3′A, IL-10-5′–592A and IL-4–589T alleles in two unique HIV-1 infected patient cohorts that represent the two distinct stages of disease progression, namely rapid progressors (RPs) and long term non-progressors (LTNPs) ( n = 12/group) were recruited. Quantitation of the gene expression of CCR5-Δ32, CCR2b-641, RANTES In1.1C, SDF-1 3′A, IL-10-5′−592A and IL-4–589T in peripheral blood mononuclear leukocytes (PBML) isolated from patients was performed by real time, quantitative (Q)-PCR using DNA was isolated from PBML. We observed that expression of these HIV-protective alleles was generally greater in the LTNP cohort than the RP cohort. LTNPs expressed more of the protective chemokine, SDF-1α than RPs, and no statistically significant difference was observed in RANTES production between the LTNPs and RPs. The LTNPs expressed significantly less amounts of cytokines IL-10 and IL-4 as compared to the RPs. Our results demonstrate that gene polymorphisms for CCR5-Δ32, CCR2b-641, RANTES In1.1C, SDF-1 3′A, IL-10-5′−592A and IL-4–589T may be used as clinical markers to predict progression of HIV-1 infections.

The plant extract Isatis tinctoria L. extract (ITE) inhibits allergen-induced airway inflammation and hyperreactivity in mice

The herbal Isatis tinctoria extract (ITE) inhibits the inducible isoform of cyclooxygenase (COX-2) as well as lipoxygenase (5-LOX) and therefore possesses anti-inflammatory properties. The extract might also be useful in allergic airway diseases which are characterized by chronic inflammation. ITE obtained from leaves by supercritical carbon dioxide extraction was investigated in ovalbumin (OVA) immunised BALB/c mice given intranasally together with antigen challenge in the murine model of allergic airway disease (asthma) with the analysis of the inflammatory and immune parameters in the lung. ITE given with the antigen challenge inhibited in a dose related manner the allergic response. ITE diminished airway hyperresponsiveness (AHR) and eosinophil recruitment into the bronchoalveolar lavage (BAL) fluid upon allergen challenge, but had no effect in the saline control mice. Eosinophil recruitment was further assessed in the lung by eosinophil peroxidase (EPO) activity at a dose of 30 microg ITE per mouse. Microscopic investigations revealed less inflammation, eosinophil recruitment and mucus hyperproduction in the lung in a dose related manner. Diminution of AHR and inflammation was associated with reduced IL-4, IL-5, and RANTES production in the BAL fluid at the 30 microg ITE dose, while OVA specific IgE and eotaxin serum levels remained unchanged. ITE, which has been reported inhibiting COX-2 and 5-LOX, reduced allergic airway inflammation and AHR by inhibiting the production of the Th2 cytokines IL-4 and IL-5, and RANTES.

Stat3-dependent acute Rantes production in vascular smooth muscle cells modulates inflammation following arterial injury in mice

Inflammation is a key component of arterial injury, with VSMC proliferation and neointimal formation serving as the final outcomes of this process. However, the acute events transpiring immediately after arterial injury that establish the blueprint for this inflammatory program are largely unknown. We therefore studied these events in mice and found that immediately following arterial injury, medial VSMCs upregulated Rantes in an acute manner dependent on Stat3 and NF-kappaB (p65 subunit). This led to early T cell and macrophage recruitment, processes also under the regulation of the cyclin-dependent kinase inhibitor p21Cip1. Unique to VSMCs, Rantes production was initiated by Tnf-alpha, but not by Il-6/gp130. This Rantes production was dependent on the binding of a p65/Stat3 complex to NF-kappaB-binding sites within the Rantes promoter, with shRNA knockdown of either Stat3 or p65 markedly attenuating Rantes production. In vivo, acute NF-kappaB and Stat3 activation in medial VSMCs was identified, with acute Rantes production after injury substantially reduced in Tnfa-/- mice compared with controls. Finally, we generated mice with SMC-specific conditional Stat3 deficiency and confirmed the Stat3 dependence of acute Rantes production by VSMCs. Together, these observations unify inflammatory events after vascular injury, demonstrating that VSMCs orchestrate the arterial inflammatory response program via acute Rantes production and subsequent inflammatory cell recruitment.

Abstract 5275: STAT3-dependent Acute RANTES Production in Vascular Smooth Muscle Cells Modulates Inflammation Following Arterial Injury

Inflammation is a key component of arterial injury, with vascular smooth muscle cell (VSMC) proliferation and neointimal formation the final outcome of this process. However, the acute events that establish the blueprint for this vascular inflammatory response are incompletely understood. To address this deficiency we examined events immediately after femoral artery wire injury in mice and identified a marked acute recruitment of macrophages and T cells, with vessel-associated CD3 + T cells increasing ~20-fold within 1 day of injury. Correspondingly RANTES, a T cell and macrophage chemo-attractant, was upregulated in vessels > 20-fold within 6 h of injury. RANTES production was modulated by p21 Cip1 ; at 6 h local RANTES was 45-fold higher in p21 −/− than wild type (WT) mice, and acute T cell infiltration was > 2-fold greater in p21 −/− than WT mice at 1 day post injury. Immune-staining and reciprocal bone marrow (BM) transplantation between WT and RANTES −/− mice identified medial VSMCs as the principal source of acute RANTES production. Unique to VSMCs, RANTES production was initiated by TNF α , but not IL-6 or gp130 (an IL-6 signal transducer). RANTES transcription was dependent on downstream binding of a complex formed between NF- κ B (p65 subunit) and STAT3 to NF- κ B binding sites in the RANTES promoter, with shRNA knockdown of either STAT3 or p65 in VSMCs markedly abrogating RANTES production. p21 Cip1 potentially modulated RANTES levels by both restraining STAT3 transcription and co-association with p65. In vivo , acute activation of NF- κ B and STAT3 in medial VSMCs was identified, with RANTES levels 6 h after injury in TNFα −/− mice significantly reduced compared to WT controls. One day after injury, RANTES −/− mice reconstituted with WT BM displayed a marked reduction in T cell and macrophage infiltration compared to identically reconstituted WT mice. Finally, we generated mice with smooth muscle cell-specific conditional STAT3-knockout ( STAT3 fl/fl ;SM22α-Cre ) and confirmed the STAT3-dependence of acute RANTES production by VSMCs. We conclude that early inflammatory cell recruitment following arterial injury is regulated by acute local RANTES production by medial VSMCs, which is in turn stimulated by TNF α and modulated by downstream NF- κ B-STAT3 signaling.

Differential Cytokine Production and Bystander Activation of Autoreactive B Cells in Response to CpG-A and CpG-B Oligonucleotides

Synthetic oligonucleotides containing CpG motifs have been shown to induce proliferation, differentiation, and cytokine production in B cells, macrophages, and dendritic cells through a TLR9-dependent mechanism. A class (CpG-A) and B class (CpG-B) oligonucleotides display distinct physical properties. CpG-A, but not CpG-B, can multimerize to form exceedingly large lattices. CpG-A cannot effectively activate B cells but does induce plasmacytoid dendritic cells to produce high levels of IFNalpha, while CpG-B is a potent B cell mitogen. In this study, we report that CpG-A is internalized by B cells, and CpG-A and CpG-B accumulate in distinct intracellular compartments. When present in the form of an immune complex (CpG-A IC), CpG-A is taken up more efficiently by AM14 IgG2a-specific B cells, and elicits a robust TLR9-dependent B cell proliferative response. B cells proliferating comparably and in a TLR9-dependent fashion in response to CpG-A IC and CpG-B exhibited distinct cytokine profiles. CpG-A IC induced enhanced production of RANTES and markedly reduced levels of IL-6 when compared with CpG-B. We also found that engagement of the AM14 BCR by a protein IC, which cannot by itself induce proliferation, promoted TLR9-dependent but BCR-independent proliferation by bystander CpG-A or fragments of mammalian dsDNA. These data identify direct and indirect mechanisms by which BCR engagement facilitates access of exogenous ligands to TLR9-associated compartments and subsequent B cell activation.

Petasites extract Ze 339 (PET) inhibits allergen‐induced Th2 responses, airway inflammation and airway hyperreactivity in mice

The herbal Petasites hybridus (butterbur) extract (Ze 339, PET) is known to have leukotriene inhibiting properties, and therefore might inhibit allergic diseases. The effect of PET was investigated in ovalbumin (OVA) immunized BALB/c mice given intranasally together with antigen challenge in the murine model of allergic airway disease (asthma) with the analysis of the inflammatory and immune parameters in the lung. PET given with the antigen challenge inhibited the allergic response. PET inhibited airway hyperresponsiveness (AHR) and eosinophil recruitment into the bronchoalveolar lavage (BAL) fluid upon allergen challenge, but had no effect in the saline control mice. Eosinophil recruitment was further assessed in the lung by eosinophil peroxidase (EPO) activity at a concentration of 100 microg PET. Microscopic investigations revealed less inflammation, eosinophil recruitment and mucus hyperproduction in the lung with 100 microg PET. Diminution of AHR and inflammation was associated with reduced IL-4, IL-5 and RANTES production in the BAL fluid with 30 microg PET, while OVA specific IgE and eotaxin serum levels remained unchanged. PET, which has been reported to inhibit leukotriene activity, reduced allergic airway inflammation and AHR by inhibiting the production of the Th2 cytokines IL-4 and IL-5, and RANTES.

P10-09. Altered release of RANTES from human, normal platelets: contribution of distinct HIV-1MN gp41 peptides

Methods We used platelets sampled from healthy, HIV-1,2 negative, normal blood donors. Platelet-Rich Plasma (PRP) was incubated after addition thrombin receptor agonist peptide or HIV env glycoprotein. PRP were centrifuged and platelet free supernatant was stored. Two recombinant gp120MN (produced in insect cells using the baculovirus expression system) and synthetic peptides of gp41MN, and mAbs to gp41: D50 and 2F5, were all obtained through the AIDS Research and Reference Reagent Program. Soluble CD62p and RANTES production in cultures were measured by specific ELISA.

Divergent intracellular pathways regulate interleukin-1β-induced miR-146a and miR-146b expression and chemokine release in human alveolar epithelial cells

We have previously reported that IL-β-induced miR-146a and miR-146b expression negatively regulates IL-8 and RANTES release in human alveolar A549 epithelial cells. To determine the intracellular pathways that regulate this response, we demonstrate IL-1β-induced activation of the nuclear factor (NF)-κB, extracellular regulated kinase (ERK)-1/2, c-jun N-terminal kinase (JNK)-1/2 and p38 mitogen activated kinase (MAP) kinase pathways. Subsequent pharmacological studies show that IL-1β-induced miR-146a, IL-8 and RANTES production was regulated via NF-κB and JNK-1/2 whilst miR-146b expression was mediated via MEK-1/2 and JNK-1/2. These divergent intracellular pathways likely explain the differential expression and biological action of the miR-146 isoforms.

Decreased Proinflammatory Cytokines Production in Children with Complicated Parapneumonic Pleural Effusion after Intrapleural Fibrinolytic Treatment

Intrapleural fibrinolytic therapy (IFT) provides clinical benefit in the treatment of complicated pleural parapneumonic effusion (CPE). Whether IFT influences the proinflammatory cytokines production and fibrinlytic activity is currently unclear. Therefore, we collected pleural effusion samples from CPE patients with IFT (study group) and patients without IFT (control group). A membrane human inflammatory cytokines array kit was used to compare the difference of targeted cytokine production between these two groups. Enzyme-linked immunosorbent assay (ELISA) methods were used for quantitative analysis of targeted cytokines and fibrinolytic enzymes. The results showed there were no significant differences between the study (n = 16) and control (n = 14) groups in patients' demographic data. After fibrinolytic therapy, the patients in the study group had significant lower plasminogen activator inhibitor (PAI) level (732.36+/-254.09 ng/mL vs 1,509.36+/-1,340.11 ng/mL, p<0.05) and higher urokinase plasminogen activator (u-PA) level (75.56+/-41.70 ng/mL vs 6.87+/-5.07 ng/mL, p<0.05) than they did before treatment. Moreover, the tissue inhibitors of metalloproteinase-2 (TIMP-2) (1,560.03+/-403.49 pg/mL vs 3,686.45+/-1,263.83 pg/mL, p<0.05) and inflammatory chemokine, regulated on activation normal T-cell expressed and secreted/chemokine (C-C motif) ligand 5 (RANTES), (293.58+/-212.93 pg/mL vs 749.27+/-53.79 pg/mL, p<0.05), were also significantly lower in the study group after fibrinolytic therapy, but not in the control group. In conclusion, intrapleural fibrinolytic treatment with urokinase could enhance fibrinolytic activity and decrease TIMP-2 and RANTES production.

Naturally acquired hemozoin by monocytes promotes suppression of RANTES in children with malarial anemia through an IL-10-dependent mechanism

Regulated upon activation, normal T-cell expressed, and secreted (RANTES, CCL-5) is an important immunoregulatory mediator that is suppressed in children with malarial anemia (MA). Although pro-inflammatory (e.g., TNF-α, IL-1β and IFN-γ) and anti-inflammatory (e.g., IL-4, IL-10 and IL-13) cytokines regulate RANTES production, their effect on RANTES in children with MA has not been determined. Since intraleukocytic malarial pigment, hemozoin (Hz), causes dysregulation in chemokine and cytokine production, the impact of naturally acquired Hz ( pfHz) on RANTES and RANTES-regulatory cytokines (TNF-α, IFN-γ, IL-1β, IL-4, IL-10, and IL-13) was examined. Circulating RANTES levels progressively declined with increasing levels of pigment-containing monocytes (PCM) ( P = 0.035). Additional experiments in cultured peripheral blood mononuclear cells (PBMC) showed that monocytic acquisition of pfHz ( in vivo) was associated with suppression of RANTES under baseline ( P = 0.001) and stimulated conditions ( P = 0.072). Although high PCM levels were associated with decreased circulating IFN-γ ( P = 0.003) and IL-10 ( P = 0.010), multivariate modeling revealed that only PCM ( P = 0.048, β = −0.171) and IL-10 ( P < 0.0001, β = −0.476) were independently associated with RANTES production. Subsequent in vitro experiments revealed that blockade of endogenous IL-10 significantly increased RANTES production ( P = 0.028) in PBMC from children with naturally acquired Hz. Results here demonstrate that monocytic acquisition of Hz suppresses RANTES production in children with MA through an IL-10-dependent mechanism.

Prostaglandin E2 suppresses staphylococcal enterotoxin–induced eosinophilia-associated cellular responses dominantly through an E-prostanoid 2–mediated pathway in nasal polyps

Recent investigations have revealed that staphylococcal enterotoxins (SEs), COX metabolism, or both might participate in the pathogenesis of eosinophilic airway diseases, such as chronic rhinosinusitis with nasal polyposis. We sought to determine whether COX metabolism, especially prostaglandin (PG) E(2), plays a significant role in SE-induced cellular responses in nasal polyps. Dispersed nasal polyp cells (DNPCs) were prepared from nasal polyps by means of enzymatic digestion. DNPCs were cultured with SEB in the presence or absence of COX inhibitors (diclofenac and indomethacin) for 72 hours; then the levels of IL-5, IL-13, RANTES, and eotaxin in the supernatants were measured. The effect of PGE(2) on SEB-induced responses by diclofenac-treated DNPCs was examined, especially in terms of receptor specificity. DNPCs produced significant amounts of IL-5, IL-13, and RANTES in response to SEB. COX inhibitors significantly increased the production of these cytokines. The degree of local eosinophilia was significantly and positively correlated with the changes in IL-5 production induced by diclofenac treatment. PGE(2) significantly and dose-dependently inhibited SEB-induced IL-5, IL-13, and RANTES production by diclofenac-treated DNPCs. E-prostanoid (EP) 2 receptor-selective agonist strongly inhibited the production of all 3 cytokines. EP3 and EP4 receptor-selective agonists partially suppressed these responses, whereas EP1 receptor-selective agonist did not. Interestingly, all of the combined treatments with 2 of the 4 EP receptor-selective agonists significantly inhibited the SEB-induced responses by diclofenac-treated DNPCs. These results suggest that PGE(2) inhibits the pathogenesis of SEB-induced eosinophilic inflammation primarily through the EP2-mediated pathway in patients with chronic rhinosinusitis with nasal polyposis.

Fn14-TRAIL, a Chimeric Intercellular Signal Exchanger, Attenuates Experimental Autoimmune Encephalomyelitis

Hallmarks of the pathogenesis of autoimmune encephalomyelitis include perivascular infiltration of inflammatory cells into the central nervous system, multifocal demyelination in the brain and spinal cord, and focal neuronal degeneration. Optimal treatment of this complex disease will ultimately call for agents that target the spectrum of underlying pathogenic processes. In the present study, Fn14-TRAIL is introduced as a unique immunotherapeutic fusion protein that is designed to exchange and redirect intercellular signals within inflammatory cell networks, and, in so doing, to impact multiple pathogenic events and yield a net anti-inflammatory effect. In this soluble protein product, a Fn14 receptor component (capable of blocking the pro-inflammatory TWEAK ligand) is fused to a TRAIL ligand (capable of inhibiting activated, pathogenic T cells). Sustained Fn14-TRAIL expression was obtained in vivo using a transposon-based eukaryotic expression vector. Fn14-TRAIL expression effectively prevented chronic, nonremitting, paralytic disease in myelin oligodendrocyte glycoprotein-challenged C57BL/6 mice. Disease suppression in this model was reflected by decreases in the clinical score, disease incidence, nervous tissue inflammation, and Th1, Th2, and Th17 cytokine responses. Significantly, the therapeutic efficacy of Fn14-TRAIL could not be recapitulated simply by administering its component parts (Fn14 and TRAIL) as soluble agents, either alone or in combination. Its functional pleiotropism was manifest in its additional ability to attenuate the enhanced permeability of the blood-brain barrier that typically accompanies autoimmune encephalomyelitis.

Macrophages Generate Reactive Oxygen Species in Response to Minimally Oxidized Low-Density Lipoprotein

Oxidative modification of low-density lipoprotein (LDL) plays a causative role in the development of atherosclerosis. In this study, we demonstrate that minimally oxidized LDL (mmLDL) stimulates intracellular reactive oxygen species (ROS) generation in macrophages through NADPH oxidase 2 (gp91phox/Nox2), which, in turn, induces production of RANTES and migration of smooth muscle cells. Peritoneal macrophages from gp91phox/Nox2 −/− mice or J774 macrophages in which Nox2 was knocked down by small interfering RNA failed to generate ROS in response to mmLDL. Because mmLDL-induced cytoskeletal changes were dependent on Toll-like receptor (TLR)4, we analyzed ROS generation in peritoneal macrophages from wild-type, TLR4 −/− , or MyD88 −/− mice and found that mmLDL-mediated ROS was generated in a TLR4-dependent, but MyD88-independent, manner. Furthermore, we found that ROS generation required the recruitment and activation of spleen tyrosine kinase (Syk) and that mmLDL also induced phospholipase PLCγ1 phosphorylation and protein kinase C membrane translocation. Importantly, the phospholipase Cγ1 phosphorylation was reduced in J774 cells expressing Syk-specific short hairpin RNA. Nox2 modulated mmLDL activation of macrophages by regulating the expression of proinflammatory cytokines interleukin-1β, interleukin-6, and RANTES. We showed that purified RANTES was able to stimulate migration of mouse aortic smooth muscle cells and addition of neutralizing antibody against RANTES abolished the migration of mouse aortic smooth muscle cells stimulated by mmLDL-stimulated macrophages. These results suggest that mmLDL induces generation of ROS through sequential activation of TLR4, Syk, phospholipase Cγ1, protein kinase C, and gp91phox/Nox2 and thereby stimulates expression of proinflammatory cytokines. These data help explain mechanisms by which endogenous ligands, such as mmLDL, can induce TLR4-dependent, proatherogenic activation of macrophages.

Analysis of Signaling Pathways Involved in Peptidoglycan-Induced RANTES Production from Murine Langerhans Cells

Background: Our previous study showed that percutaneous application of peptidoglycan from Staphylococcus aureus induced eosinophil infiltration in murine skin through production of CCL5/RANTES (regulated upon activation in normal T cells expressed and secreted) from epidermal Langerhans cells. Although it is well known that peptidoglycan is an agonist of Toll-like receptor (TLR)-2, it is unclear whether other TLR agonists are able to induce RANTES production from Langerhans cells. Methods: Langerhans cells were purified from murine epidermal cells by the panning method using anti-IA^d monoclonal antibody. RANTES production by Langerhans cells was investigated by RT-PCR and ELISA. Analysis of the signaling pathways responsible for RANTES production by Langerhans cells was performed by ELISA using N-acetyl-L-cysteine, SP600125, SB203580 and PD98059, which are specific inhibitors of NF-κB activation, JNK, p38 MAPK and ERK, respectively, and was finally confirmed by Western blot analysis. Results: Peptidoglycan, poly(I:C), lipopolysaccharide and CpG DNA, which signal through TLR-2, TLR-3, TLR-4 and TLR-9, respectively, were found to strongly induce RANTES production. Treatment with N-acetyl-L-cysteine inhibited all TLR agonist-induced RANTES production. However, treatment with SP600125 did not inhibit CpG DNA-induced RANTES production. Furthermore, treatment with SB203580 inhibited only peptidoglycan- and lipopolysaccharide-induced RANTES production and the inhibition was correlated with that of p38 MAPK phosphorylation. Conclusion: These results suggest that the signaling pathway of RANTES production from murine Langerhans cells induced by different TLR stimuli is not necessarily the same, and that inhibition of p38 MAPK may be a more specific therapeutic target for eosinophilic inflammation in patients with atopic dermatitis associated with S. aureus colonization.

Glycogen synthase kinase-3 negatively regulates anti-inflammatory interleukin-10 for lipopolysaccharide-induced iNOS/NO biosynthesis and RANTES production in microglial cells

Glycogen synthase kinase-3 negatively regulates anti-inflammatory interleukin-10 for lipopolysaccharide-induced iNOS/NO biosynthesis and RANTES production in microglial cells

Genetic correlates of protection against HIV infection: the ally within

Repeated exposure to HIV does not necessarily result in infection and HIV infection does not inevitably lead to the development of the AIDS. Multiple immunological and genetic features can confer resistance to HIV acquisition and progression at different steps in viral infection; a full understanding of these mechanisms could result in the development of novel therapeutic and vaccine approaches for HIV infection. In this review, we focus on the genetic mechanisms associated with resistance to HIV infection and to the progression to AIDS.

Megalin contributes to the early injury of proximal tubule cells during nonselective proteinuria

Megalin, a member of the LDL receptor family, is expressed on the apical membrane of proximal tubules and serves as an endocytic scavenger of filtered proteins and hence might contribute to the tubule injury as a consequence of glomerular disease. To study its role, we crossed megalin knockout mosaic mice (lacking megalin expression in 60% of proximal tubule cells) with NEP25 mice (a transgenic line expressing human CD25 in the podocyte). Treatment of this transgenic mouse with the immunotoxin causes nephrotic syndrome, focal segmental glomerulosclerosis and tubule-interstitial injury. Following this treatment, the double transgenic mice had massive non-selective proteinuria and mild glomerular and tubular injury. Comparison of megalin-containing to megalin-deficient proximal tubule cells within each kidney showed that albumin, immunoglobulin light chain, IgA and IgG were preferentially accumulated in proximal tubule cells expressing megalin. Tubule injury markers such as heme-oxygenase-1, monocyte chemoattractant protein-1 and cellular apoptosis were also preferentially found in these megalin-expressing cells. These results show that megalin plays a pivotal role in the reabsorption of small to large molecular size proteins and provides direct in vivo evidence that reabsorption of filtered proteins triggers events leading to tubule injury.

Monocytes downregulate the early stage of collagen-induced platelet activation by a PECAM-1-dependent mechanism.

Blood vessel damage results in exposure of the subendothelial matrix, to which platelets adhere. Monocytes are recruited and activated at the site of injury. Here we studied the effect of monocytes on platelet activation induced by exposure to fibrillar collagen. Washed platelets and isolated monocytes (100/1) were coincubated with type I collagen in static adhesion conditions or in suspension. Platelet activation was assessed by measuring RANTES production and alpha-granule secretion. Platelet adherence on immobilized collagen was analyzed by fluorescence confocal microscopy. Cell-cell contacts were prevented by incubating platelets and monocytes in transwell coculture dishes. Experiments were also performed in the presence of soluble recombinant platelet endothelial cell adhesion molecule-1 (PECAM-1) or of antibodies to PECAM-1. Unexpectedly, unstimulated monocytes limited the initial phase of platelet activation by fibrillar collagen. In adhesion conditions, monocytes reduced the secretion by platelets of the inflammatory chemokine RANTES and of beta-thromboglobulin and the formation of platelet aggregates. The inhibitory effect of monocytes on platelet activation required direct cell-cell contacts between platelets and monocytes. Monocytes also inhibited collagen-induced platelet activation in suspension conditions as assessed by the reduction of P-selectin exposure and RANTES secretion. A recovery of platelet responses was observed in the presence of soluble PECAM-1 and of PECAM-1.3 Fab, indicating that PECAM-1 is involved in monocyte-triggered downregulation of platelet reactivity. Our data provide the first evidence that unstimulated monocytes limit the initial phase of platelet activation by collagen via a mechanism that is, at least in part, PECAM-1-dependent.