Induction of Mn SOD in human monocytes without  inflammatory cytokine production by a mutant endotoxin

Tian, Lei; White, J. E.; Lin, Hung Yun; Haran, Visa S.; Sacco, Joseph; Chikkappa, G.; Davis, Faith B.; Davis, Paul J.; Tsan, Min‐Fu

doi:10.1152/ajpcell.1998.275.3.c740

Cited by 126 publications

(39 citation statements)

References 35 publications

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“…In addition to charge interactions, we demonstrated the critical role of the interaction between MD-2 hydrophobic residues and lipid A acyl chains. A nonpathogenic penta-acylated LPS lacking the secondary myristoyl chain did not induce immunological responses in human cells (3,30,31). We found that the mutant LPS did not bind to human MD-2.…”

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confidence: 72%

Comparison of Lipopolysaccharide-Binding Functions of CD14 and MD-2

Koraha¹,

Tsuneyoshi²,

Kimoto³

et al. 2005

Clin Vaccine Immunol

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Prior to being recognized by the cell surface Toll-like receptor 4/MD-2 complex, lipopolysaccharide (LPS) in the bacterial outer membrane has to be processed by LPS-binding protein and CD14. CD14 forms a complex with monomeric LPS extracted by LPS-binding protein and transfers LPS to the cell surface signaling complex. In a previous study, we prepared a functional recombinant MD-2 using a bacterial expression system. We expressed the recombinant protein in Escherichia coli as a fusion protein with thioredoxin and demonstrated specific binding to LPS. In this study, we prepared recombinant CD14 fusion proteins using the same approach. Specific binding of LPS was demonstrated with a recombinant protein containing 151 aminoterminal residues. The region contained a hydrophilic region and the first three leucine-rich repeats (LRRs). The LRRs appeared to contribute to the binding because removal of the region resulted in a reduction in the binding function. LPS binding to the recombinant MD-2 was resistant to detergents. On the other hand, the binding to CD14 was prevented in the presence of low concentrations of detergents. In the case of human MD-2, the secondary myristoyl chain of LPS added by LpxM was required for the binding. A nonpathogenic penta-acyl LPS mutant lacking the myristoyl chain did not bind to MD-2 but did so normally to CD14. The broader LPS-binding spectrum of CD14 may allow recognition of multiple pathogens, and the lower affinity for LPS binding of CD14 allows transmission of captured materials to MD-2.Gram-negative bacterial infection often causes lethal endotoxic shock. Lipopolysaccharide (LPS) is the major component of the bacterial outer membrane and is the causative agent of shock (27,35). LPS is recognized by both innate and adaptive immune systems. LPS is composed of O-antigen repeats, the core region, and lipid A. The O-antigen structures vary by strain and are recognized by the adaptive immune system, resulting in the production of specific antibodies. The target structure for the innate immune system is lipid A, which has conserved structures (27). Toll-like receptors (TLRs) play important roles in the recognition of pathogen-associated molecular patterns (PAMPs) (17). TLR4 is the major receptor for LPS and causes intracellular signal transduction (8,25,26). Among the TLR family proteins, TLR4 is unique in having an associated molecule, MD-2 (29). MD-2 is thought to be a secretory glycoprotein from the deduced amino acid sequences but is anchored on the cell surface by TLR4. The association of MD-2 is required for cell surface expression of TLR4. In addition, MD-2 has been shown to participate in the recognition of ligands (22,29). The direct binding of LPS to MD-2 has been shown in several assay systems (16,34,38). MD-2 was identified as a homologue of MD-1, which is physically associated with RP105 (19). RP105 is a B-cell-specific cell surface glycoprotein with leucine-rich repeats (LRRs) in the extracellular domain in the same way as with TLRs (20,21). The RP105/MD-1 complex was also...

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mentioning

confidence: 72%

Comparison of Lipopolysaccharide-Binding Functions of CD14 and MD-2

Koraha¹,

Tsuneyoshi²,

Kimoto³

et al. 2005

Clin Vaccine Immunol

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“…However, in contrast to the wild-type LPS, nmLPS fails to induce significant production of TNF␣ and does not induce the phosphorylation and nuclear translocation of MAPK (Tian et al, 1998). These results suggest that induction of TNF␣ and MnSOD in human monocytes by LPS are, at least in part, regulated through different signal transduction pathways.…”

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confidence: 72%

“…Human mononuclear cells were isolated from venous blood of normal volunteers (after explaining the nature and possible risks of the studies and obtaining informed consents) using Isolymph (Gallard-Schlesinger Industries Inc., Carle Place, NY) as described previously (Tian et al, 1998). Cells (5 ϫ 10 6 /ml in RPMI 1640 plus antibiotics and 10% autologous serum) were allowed to adhere onto tissue culture plates for 2 h. Adherent cells which consisted of approximately 90% monocytes as judged by the nonspecific esterase staining, were used for the current studies.…”

Section: Isolation Of Human Monocytesmentioning

confidence: 99%

“…We have recently demonstrated that a mutant Escherichia coli LPS-lacking myristoyl fatty acid at the 3Ј R-3-hydroxymyristate position of the lipid A moiety (nonmyristoyl LPS, nmLPS) (Somerville et al, 1996), retains its full capacity to coagulate limulus amebocyte lysate as compared to the wild-type E. coli LPS, and markedly stimulates the activation of NFB and the induction of MnSOD mRNA and enzyme activity in human monocytes (Tian et al, 1998). However, in contrast to the wild-type LPS, nmLPS fails to induce significant production of TNF␣ and does not induce the phosphorylation and nuclear translocation of MAPK (Tian et al, 1998).…”

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confidence: 99%

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Differential induction of tumor necrosis factor ? and manganese superoxide dismutase by endotoxin in human monocytes: Role of protein tyrosine kinase, mitogen-activated protein kinase, and nuclear factor ?B

et al. 2000

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A mutant Escherichia coli lipopolysaccharide (LPS) lacking myristoyl fatty acid markedly stimulates the activity of manganese superoxide dismutase (MnSOD) without inducing tumor necrosis factor alpha (TNFalpha) production by human monocytes (Tian et al., 1998, Am J Physiol 275:C740.), suggesting that induction of MnSOD and TNFalpha by LPS are regulated through different signal transduction pathways. The protein tyrosine kinase (PTK)/mitogen-activated protein kinase (MAPK) pathway plays an important role in the LPS-induced TNFalpha production. In the current study, we determined the effects of PTK inhibitors, genistein and herbimycin A, on the induction of MnSOD and TNFalpha in human monocytes. Genistein (10 microg/ml) and herbimycin A (1 microg/ml) markedly inhibited LPS-induced protein tyrosine phosphorylation, phosphorylation and nuclear translocation of MAPK (p42 ERK, extracellular signal-regulated kinase), and increases in the steady state level of TNFalpha mRNA as well as TNFalpha production. In contrast, at similar concentrations, genistein and herbimycin A had no effect on the LPS-induced activation of nuclear factor kappaB (NFkappaB) and induction of MnSOD (mRNA and enzyme activity) in human monocytes. In addition, inhibition of NFkappaB activation by gliotoxin and pyrrodiline dithiocarbamate, inhibited LPS induction of TNFalpha and MnSOD mRNAs. These results suggest that (1) while PTK and MAPK are essential for the production of TNFalpha, they are not necessary for the induction of MnSOD by LPS, and (2) while activation of NFkappaB alone is insufficient for the induction of TNFalpha mRNA by LPS, it is necessary for the induction of TNFalpha as well as MnSOD mRNAs.

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“…Clones from the up-regulated fraction included 68 known genes, 35 expressed sequence tags, and nine novel sequences, whereas clones from the down-regulated fraction included 209 known genes, 111 expressed sequence tags, and five novel sequences. In the up-regulated fraction there were many known PMA-induced genes such as IL-8, tumor necrosis factor ␣, macrophage inflammatory protein 1, and superoxide dismutase 2 (11)(12)(13)(14). There was very little overlap between the up-and down-regulated sets of genes, except for the presence of a small number of microbeads bearing up-regulated B94 (M92357) cDNAs in the down-regulated fraction and some microbeads bearing downregulated 23 kDa basic protein transcript (X56932) in the up-regulated fraction.…”

Section: Analysis Of Differential Gene Expressionmentioning

confidence: 99%

In vitro cloning of complex mixtures of DNA on microbeads: physical separation of differentially expressed cDNAs

2000

Current Opinion in Plant Biology

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We describe a method for cloning nucleic acid molecules onto the surfaces of 5-m microbeads rather than in biological hosts. A unique tag sequence is attached to each molecule, and the tagged library is amplified. Unique tagging of the molecules is achieved by sampling a small fraction (1%) of a very large repertoire of tag sequences. The resulting library is hybridized to microbeads that each carry Ϸ10 6 strands complementary to one of the tags. About 10 5 copies of each molecule are collected on each microbead. Because such clones are segregated on microbeads, they can be operated on simultaneously and then assayed separately. To demonstrate the utility of this approach, we show how to label and extract microbeads bearing clones differentially expressed between two libraries by using a fluorescence-activated cell sorter (FACS). Because no prior information about the cloned molecules is required, this process is obviously useful where sequence databases are incomplete or nonexistent. More importantly, the process also permits the isolation of clones that are expressed only in given tissues or that are differentially expressed between normal and diseased states. Such clones then may be spotted on much more cost-effective, tissue-or disease-directed, low-density planar microarrays.DNA analysis ͉ gene expression ͉ parallel cloning ͉ fluid microarray

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Induction of Mn SOD in human monocytes without inflammatory cytokine production by a mutant endotoxin

Cited by 126 publications

References 35 publications

Comparison of Lipopolysaccharide-Binding Functions of CD14 and MD-2

Comparison of Lipopolysaccharide-Binding Functions of CD14 and MD-2

Differential induction of tumor necrosis factor ? and manganese superoxide dismutase by endotoxin in human monocytes: Role of protein tyrosine kinase, mitogen-activated protein kinase, and nuclear factor ?B

In vitro cloning of complex mixtures of DNA on microbeads: physical separation of differentially expressed cDNAs

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