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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhaled endotoxin (lipopolysaccharide, LPS) can induce acute lung injury and at high doses may lead to respiratory distress syndrome. Using a mouse model of acute lung inflammation induced by inhalation of low doses of LPS we examined the kinetics of chemokine, proinflammatory cytokine, and metallothionein. Eight-week-old C57BL/6 mice were dosed for 10 min with LPS, resulting in an estimated alveolar dose of < 10 ng LPS/mouse, and euthanized 2,6, or 24 h postexposure. Analysis of bronchoalveolar lavage fluid demonstrated increased polymorphonuclear neutrophils (PMNs) of 6.94, 32.7, and 38.8% after 2, 6, and 24 h, respectively. Examination of proinflammatory cytokine, chemokine, and Mt mRNA in the lung revealed increases for messages encoding IL-1 alpha, IL-1 beta, IL-6, IFN-gamma, TNF alpha, Eotaxin, MIP-1 alpha, MIP-1 beta, MIP-2, Mt, and IP-10, while messages encoding IL-12, IL-10, IFN-beta, Ltn, MCP-1, TGF beta 1 + 2, and RANTES were unchanged from those of sham-exposed mice 2 h postexposure. By 6 h most messages had returned to near control levels. Comparison to 5 mg/kg body weight intraperitoneal injection and 5 micrograms/mouse intratracheal instillation 2 h postexposure demonstrated similar message responses. Our results demonstrate that low levels of LPS exposure by inhalation induce a strong PMN response and a selective cytokine response in the lung, supporting the hypothesis that PMNs may regulate inflammatory processes via cytokine and chemokine response.
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PMID:Pulmonary cytokine and chemokine mRNA levels after inhalation of lipopolysaccharide in C57BL/6 mice. 1004 33

Sequestration of neutrophils and release of histotoxic mediators are considered important for the development of pathologic alterations of the lung defined as adult respiratory distress syndrome. Mechanisms of inflammatory lung injury caused by abdominal sepsis were investigated using the colon ascendens stent peritonitis (CASP) model that closely mimics the human disease. In the CASP model, a continuous leakage of intraluminal bacteria into the peritoneal cavity is induced by implantation of a stent in the ascending colon, generating a septic focus. In contrast to the cecal ligation and puncture model of peritonitis, survival of mice following CASP surgery is dependent on IFN-gamma, but independent of tumor necrosis factor (TNF). Here we show that the systemic inflammation induced by CASP surgery results in a rapid and profound increase of lung vascular permeability that was associated with the activation and recruitment of neutrophils to the lung. Activation of circulating granulocytes was characterized by increased production of serine proteinases and reactive oxygen metabolites, as well as elevated expression of cell surface Mac-1. Expression of MIP-2, KC, MIP-1alpha and E-selectin mRNA in lung was strongly increased within 3 h following CASP surgery, whereas up-regulation of IP-10, MCP-1 and P-selectin was delayed. In contrast, induction of RANTES, LIX, ICAM-1 and VCAM-1 mRNA was weak or not detectable after CASP surgery. Importantly, recruitment of leukocytes to the lung was normal in lipopolysaccharide-resistant mice, and was not affected by antibody neutralization of TNF or the chemokines MIP-2 and KC.
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PMID:Mechanisms of acute inflammatory lung injury induced by abdominal sepsis. 1006 20

Monocytes/macrophages (MO/Mphi) are the major target cells for both dengue virus (DV) and bacterial lipopolysaccharide (LPS), and the aim of this study was to define their interactions. We had found that LPS markedly suppressed DV infection of primary human MO/Mphi when it was added to cultures prior to or together with, but not after, viral adsorption. The inhibitory effect of LPS was direct and specific and was not mediated by LPS-induced secretion of cytokines and chemokines such as tumor necrosis factor alpha, interleukin-1beta (IL-1beta), IL-6, IL-8, IL-12, alpha interferon, MIP-1alpha, and RANTES. In fact, productive DV infection was not blocked but was just postponed by LPS, with a time lag equal to one viral replication cycle. Time course studies demonstrated that LPS was only effective in suppressing DV infection of MO/Mphi that had not been previously exposed to the virus. At various time points after viral adsorption, the level of unbound viruses that remained free in the culture supernatants of LPS-pretreated cultures was much higher than that of untreated controls. These observations suggest that the LPS-induced suppression of DV replication was at the level of virus attachment and/or entry. Blockade of the major LPS receptor, CD14, with monoclonal antibodies MY4 or MoS39 failed to inhibit DV infection but could totally abrogate the inhibitory effect of LPS. Moreover, human serum could significantly enhance the LPS-induced DV suppression in a CD14-dependent manner, indicating that the "binding" of LPS to CD14 was critical for the induction of virus inhibition. Taken together, our results suggest that LPS blocked DV entry into human MO/Mphi via its receptor CD14 and that a CD14-associated cell surface structure may be essential for the initiation of a DV infection.
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PMID:Bacterial lipopolysaccharide inhibits dengue virus infection of primary human monocytes/macrophages by blockade of virus entry via a CD14-dependent mechanism. 1007 10

Macrophages are targeted by environmental pollutants and play a role in allergic inflammation. We explored the molecular basis for induction of RANTES (regulated upon activation, normal T-cells expressed and secreted) mRNA by lipopolysaccharide (LPS) and the redox-active quinone, tert-butylhydroxyquinone (tBHQ). We demonstrate that transcriptional activation of the human RANTES promoter by LPS is dependent on specific AP-1 and NF-kappaB response elements, which are regulated by c-Jun N-terminal kinase (JNK) and NF-kappaB kinase cascades, respectively. The transcriptional activation of the TRE3/4 site is mediated through the transcriptional activation of c-Jun by JNK. A c-Jun mutant which lacks a transcriptional activation domain interfered in the activation of the RANTES promoter. Similarly, kinase-inactive NF-kappaB inducing kinase interfered in the activation of the RANTES promoter. While activation of the RANTES promoter could also be blocked by the downstream kinase-inactive IkappaB kinases, only IKKalpha appears to be LPS-inducible. tBHQ also exerted subtle effects on the human RANTES promoter and induced mRNA expression in parallel with generating NF-kappaB shift complexes.
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PMID:Activation of the human RANTES gene promoter in a macrophage cell line by lipopolysaccharide is dependent on stress-activated protein kinases and the IkappaB kinase cascade: implications for exacerbation of allergic inflammation by environmental pollutants. 1007 57

Dendritic cells (DC) are highly motile antigen-presenting cells that are recruited to sites of infection and inflammation to antigen uptake and processing. Then, to initiate T cell-dependent immune responses, they migrate from non-lymphoid organs to lymph nodes and the spleen. Since chemokines have been involved in human DC recruitment, we investigated the role of chemokines on mouse DC migration using the mouse growth factor-dependent immature DC line (D1). In this study, we characterized receptor expression, responsiveness to chemoattractants and chemokine expression of D1 cells during the maturation process induced by lipopolysaccharide (LPS). MIP-1alpha and MIP-5 were found to be the most effective chemoattractants, CCR1 was the main receptor expressed and modulated during LPS treatment, and MIP-2, RANTES, IP-10 and MCP-1 were the chemokines modulated during DC maturation. Thus, murine DC respond to a unique set of CC and CXC chemokines, and the maturational stage determines the program of chemokine receptors and chemokines that are expressed. Since CCR1 is modulated during the early phases of DC maturation, our results indicate that the CCR1 receptor may participate in the recruitment and maintenance of DC at the inflammatory site.
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PMID:Upon dendritic cell (DC) activation chemokines and chemokine receptor expression are rapidly regulated for recruitment and maintenance of DC at the inflammatory site. 1036 Sep 72

Human immunodeficiency virus type 1 (HIV-1) requires, in addition to CD4, coreceptors of the CC or CXC chemokine families for productive infection of T cells and cells of the monocyte-macrophage lineage. Based on the hypothesis that coreceptor expression on alveolar macrophages (AM) may influence HIV-1 infection of AM in the lung, this study analyzes the expression and utilization of HIV-1 coreceptors on AM of healthy individuals. AM were productively infected with five different primary isolates of HIV-1. Levels of surface expression of CCR5, CXCR4, and CD4 were low compared to those of blood monocytes, but CCR3 was not detectable. mRNA for CCR5, CXCR4, CCR2, and CCR3 were all detectable, but to varying degrees and with variability among donors. Expression of CCR5, CXCR4, and CCR2 mRNA was downregulated following stimulation with lipopolysaccharide (LPS). In contrast, secretion of the chemokines RANTES, MIP-1alpha, and MIP-1beta was upregulated with LPS stimulation. Interestingly, HIV-1 replication was diminished following LPS stimulation. Infection of AM with HIV-1 in the presence of the CC chemokines demonstrated blocking of infection. Together, these studies demonstrate that AM can be infected by a variety of primary HIV-1 isolates, AM express a variety of chemokine receptors, the dominant coreceptor used for HIV entry into AM is CCR5, the expression of these receptors is dependent on the state of activation of AM, and the ability of HIV-1 to infect AM may be modulated by expression of the chemokine receptors and by chemokines per se.
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PMID:Expression and use of human immunodeficiency virus type 1 coreceptors by human alveolar macrophages. 1036 38

Using human fetal microglial cell cultures, we found that the gram-negative bacterial cell wall component lipopolysaccharide (LPS) stimulated RANTES (regulated upon activation of normal T cell expressed and secreted) production through the protein kinase C signaling pathway and that activation of transcription nuclear factor (NF)-kappaB was required for this effect. Similarly, the proinflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor-alpha dose-dependently stimulated microglial cell RANTES production via NF-kappaB activation. Anti-inflammatory cytokines, IL-10, and transforming growth factor (TGF)-beta sequentially inhibited LPS- and cytokine-induced microglial cell NF-kappaB activation, RANTES mRNA expression, and protein release. Proinflammatory cytokines but not LPS also stimulated RANTES production by human astrocytes. These findings demonstrate that human microglia synthesize RANTES in response to proinflammatory stimuli, and that the anti-inflammatory cytokines IL-10 and TGF-beta down-regulate the production of this beta-chemokine. These results may have important therapeutic implications for inflammatory diseases of the brain.
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PMID:Inhibition of microglial cell RANTES production by IL-10 and TGF-beta. 1038 Sep 4

Macrophage-derived cytokines and chemokines are involved at multiple steps of immune and inflammatory responses, and the transcriptional factor NF-kappaB appears to play a pivotal role in their coordinated upregulation. The anti-inflammatory agents salicylates have been proposed to act in part by inhibiting NF-kappaB. We have therefore studied the effects of sodium salicylate on lipopolysaccharide (LPS)-induced kappaB-binding activity and on cytokine and chemokine gene expression in the RAW264.7 murine macrophage cell line and compared them to those of an established NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC). PDTC (100 microM) completely abrogated LPS-induced kappaB-binding activity and also profoundly inhibited the induction of interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-10, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and MCP-1 and, to a lesser extent, leukemia inhibitory factor, RANTES, and IL-1Ra. In contrast, sodium salicylate (15 to 20 mM) had no effect on NF-kappaB activation but, nevertheless, suppressed several LPS-induced cytokine and chemokine genes to a degree similar to that obtained with PDTC. However, compared to PDTC, sodium salicylate caused significantly less inhibition of IL-1Ra and IL-10 gene expression after LPS stimulation. Neither LPS-induced MIP-1alpha, MIP-1beta, nor MIP-2 was significantly affected by PDTC or sodium salicylate, demonstrating that NF-kappaB is dispensable for the transcriptional regulation of these genes by LPS. In summary, these results suggest that both NF-kappaB-dependent and NF-kappaB-independent pathways are necessary for the induction by LPS of a complex cytokine and chemokine response. In the RAW264.7 macrophage cell line, suprapharmacological concentrations of sodium salicylate exert a potent inhibitory effect on LPS-induced cytokine gene induction but appear to accomplish this by interfering with NF-kappaB-independent pathways of activation.
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PMID:Inhibition of cytokine gene expression by sodium salicylate in a macrophage cell line through an NF-kappaB-independent mechanism. 1039 64

The cellular infiltration found during CNS inflammation consists of monocytes and activated T cells, suggesting the presence of cell-specific chemotactic signals during inflammatory responses. Astrocyte chemokine expression might contribute to site-specific leukocyte infiltration within the CNS. To investigate the factors that regulate astrocyte chemokine expression, we examined the ability of human fetal astrocytes to induce beta-family chemokine mRNA. Astrocyte-derived monocyte chemoattractant protein-1 (MCP-1), RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta mRNA were easily induced by lipopolysaccharide and/or the proinflammatory cytokines (IFN-gamma and/or TNF-alpha), respectively. Addition of both IFN-gamma and TNF-alpha together did not lead to an additive effect but resulted in the inhibition of MCP-1 and MIP-1beta mRNA expression, indicating that interaction between chemokines and cytokines may play a key role in regulating the local immune response of resident and infiltrating cells at the site of lesion. Interestingly, ultraviolet light-inactivated measles virus, but not cytomegalovirus, strongly induced expression of MCP-1, RANTES, MIP-1alpha, and MIP-1beta mRNA in human embryonic astrocytes, especially MCP-1 and MIP-1beta. An association occurs between the beta-family chemokine expression in astrocytes and inflammatory factors/virus, suggesting a possible role for beta-family chemokines in the pathogenesis of CNS inflammatory disease.
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PMID:Induction of beta-family chemokines mRNA in human embryonic astrocytes by inflammatory cytokines and measles virus protein. 1040 24

Eosinophil infiltration of tissue is a hallmark of nasal polyposis and asthma in both atopic and nonatopic patients. Structural cells like airway fibroblasts are a rich source of cytokines and inflammatory mediators. In order to verify whether airway fibroblasts play a role in eosinophilic infiltration, we investigated the release of eosinophil chemotactic and activating factors from airway fibroblasts when stimulated with nonallergenic exogenous agents such as endotoxin (lipopolysaccharide; LPS). Using a number of primary human airway tissue-derived fibroblast lines, we demonstrated that LPS could induce the gene expression and production of RANTES (regulated and normal T cell expressed and presumably secreted) and granulocyte/macrophage colony-stimulating factor (GM-CSF) only in nasal but not in pharyngeal, tracheal, bronchial, and lung fibroblasts. This selective responsiveness of nasal fibroblasts to LPS was time and dose dependent. These findings suggest that nasal fibroblasts may play an important role in the recruitment and activation of eosinophils into nasal polyps through the release of RANTES and GM-CSF.
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PMID:Distinct expression of RANTES and GM-CSF by lipopolysaccharide in human nasal fibroblasts but not in other airway fibroblasts. 1047 37


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