scholarly journals Molecular characterization of the constitutive expression of the plasma platelet-activating factor acetylhydrolase gene in macrophages

2003 ◽  
Vol 375 (2) ◽  
pp. 351-363 ◽  
Author(s):  
Xiaoqing WU ◽  
Thomas M. McINTYRE ◽  
Guy A. ZIMMERMAN ◽  
Stephen M. PRESCOTT ◽  
Diana M. STAFFORINI
Keyword(s):  
Platelet Activating Factor ◽  
Constitutive Expression ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Band Shift ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Nuclear Extracts ◽  
Mediators Of Inflammation ◽  
Human And Mouse

Plasma platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase that inactivates platelet-activating factor (PAF) and PAF-like lipids to generate products with little or no biological activity. The levels of circulating PAF-AH correlate with several disease syndromes. We previously reported that mediators of inflammation regulate the expression of the human PAF-AH gene at the transcriptional level. In the present paper, we characterize the constitutive expression of plasma PAF-AH using the mouse gene as a model system, and we report comparative results obtained using human and mouse promoter constructs. We first cloned, sequenced and analysed the promoter region of the murine plasma PAF-AH (mPAF-AH) gene and found that this gene lacks a canonical TATA box. We demonstrated that the cis-elements required for basal transcription are localized within the −316 to −68 bp region. In vitro band-shift and supershift assays showed that Sp1 and Sp3 transcription factors from RAW264.7 and J774A.1 macrophage nuclear extracts bound strongly to a distal GC-rich site within −278/−243 [specificity protein (Sp-A)] and to a proximal TC-rich motif within −150/−114 (Sp-B). In addition, we observed weak binding to a GA-rich site within −110/−82 (Sp-C). The regions containing Sp-B and Sp-C are highly conserved between the human and mouse genes. Forced expression of Sp1 or Sp3 in Sp-lacking Drosophila SL2 cells induced markedly the activity of the exogenous mPAF-AH promoter in a dose-dependent manner, and this induction was dependent on the presence of intact Sp-A and Sp-B. Interestingly, we found that the Sp1- and Sp3-associated DNA-binding activities increased during the maturation of primary human monocytes into macrophages in cell culture. These results demonstrate that Sp1 and Sp3 are key factors that contribute to the basal, constitutive transcription of the plasma PAF-AH gene in macrophages.

scholarly journals Protein polyglutamylation catalyzed by the bacterial calmodulin-dependent pseudokinase SidJ

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alan Sulpizio ◽  
Marena E Minelli ◽  
Min Wan ◽  
Paul D Burrowes ◽  
Xiaochun Wu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Ubiquitin Ligase ◽  
Legionella Pneumophila ◽  
Kinase Activity ◽  
Effector Protein ◽  
Dependent Manner ◽  
Biochemical Analyses ◽  
Human And Mouse

Pseudokinases are considered to be the inactive counterparts of conventional protein kinases and comprise approximately 10% of the human and mouse kinomes. Here, we report the crystal structure of the Legionella pneumophila effector protein, SidJ, in complex with the eukaryotic Ca2+-binding regulator, calmodulin (CaM). The structure reveals that SidJ contains a protein kinase-like fold domain, which retains a majority of the characteristic kinase catalytic motifs. However, SidJ fails to demonstrate kinase activity. Instead, mass spectrometry and in vitro biochemical analyses demonstrate that SidJ modifies another Legionella effector SdeA, an unconventional phosphoribosyl ubiquitin ligase, by adding glutamate molecules to a specific residue of SdeA in a CaM-dependent manner. Furthermore, we show that SidJ-mediated polyglutamylation suppresses the ADP-ribosylation activity. Our work further implies that some pseudokinases may possess ATP-dependent activities other than conventional phosphorylation.

UV cross-linking identifies four polypeptides that require the TATA box to bind to the Drosophila hsp70 promoter

1990 ◽  
Vol 10 (8) ◽  
pp. 4233-4238
Author(s):  
D S Gilmour ◽  
T J Dietz ◽  
S C Elgin
Keyword(s):  
Specific Protein ◽  
Cross Linking ◽  
Dependent Manner ◽  
Hsp70 Promoter ◽  
Intimate Contact ◽  
Nuclear Extracts ◽  
Multicomponent Complex ◽  
Tata Sequence ◽  
Drosophila Embryos

A protein fraction that requires the TATA sequence to bind to the hsp70 promoter has been partially purified from nuclear extracts of Drosophila embryos. This TATA factor produces a large DNase I footprint that extends from -44 to +35 on the promoter. A mutation that changes TATA to TATG interferes both with the binding of this complex and with the transcription of the hsp70 promoter in vitro, indicating that this interaction is important for transcriptional activity. Using a highly specific protein-DNA cross-linking assay, we have identified four polypeptides that require the TATA sequence to bind to the hsp70 promoter. Polypeptides of 26 and 42 kilodaltons are in intimate contact with the TATA sequence. Polypeptides of 150 and 60 kilodaltons interact within the region from +24 to +47 in a TATA-dependent manner. Both the extended footprint and the polypeptides identified by UV cross-linking indicate that the Drosophila TATA factor is a multicomponent complex.

scholarly journals Suppression of interleukin 8 production by progesterone in rabbit uterine cervix

1994 ◽  
Vol 301 (1) ◽  
pp. 183-186 ◽  
Author(s):  
A Ito ◽  
K Imada ◽  
T Sato ◽  
T Kubo ◽  
K Matsushima ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Interleukin 1 ◽  
Interleukin 8 ◽  
Cervical Ripening ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Necrosis Factor Alpha ◽  
Steady State Levels ◽  
Neutrophil Chemotactic Factor

Uterine cervical fibroblasts prepared from rabbits at 23 days of gestation were found to produce spontaneously the neutrophil chemotactic factor/interleukin 8 (IL-8). When the cells were treated with recombinant human interleukin 1 alpha and 1 beta (rhIL-1 alpha and -1 beta), both cytokines similarly enhanced the production of IL-8 in a dose-dependent manner. Recombinant tumour necrosis factor alpha also enhanced its production to a lesser extent, but interleukin 6 failed to modulate the production. Physiological concentrations of progesterone suppressed both the spontaneous and IL-1-mediated production of IL-8 in parallel with the decrease in the steady-state levels of its mRNA. These suppressive actions of progesterone were offset by co-treatment of cells with a progesterone antagonist, mifepristone (RU486). In conclusion, basal and IL-1-induced IL-8 production in rabbit uterine cervical fibroblasts is down-regulated by progesterone at the transcriptional level. These results obtained in vitro and our previous observations indicating that progesterone modulates the extra-cellular matrix breakdown via the suppression of production of matrix metalloproteinases and the augmentation of production matrix metalloproteinases and the augmentation of production of their specific inhibitors (TIMP-1) [Sato, Ito, Mori, Yamashita, Hayakawa and Nagase (1991) Biochem. J. 275, 645-650] may explain the mechanisms of the maintenance of pregnancy until parturition and the acceleration of uterine cervical ripening and dilatation at term.

scholarly journals The Transcriptional Regulator VqmA Increases Expression of the Quorum-Sensing Activator HapR in Vibrio cholerae

2006 ◽  
Vol 188 (7) ◽  
pp. 2446-2453 ◽  
Author(s):  
Zhi Liu ◽  
Ansel Hsiao ◽  
Adam Joelsson ◽  
Jun Zhu
Keyword(s):  
Quorum Sensing ◽  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Constitutive Expression ◽  
Physiological Role ◽  
Transcriptional Regulator ◽  
Protease Production ◽  
Dependent Manner ◽  
Cell Densities

ABSTRACT Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. A number of environmental stimuli regulate virulence gene expression in V. cholerae, including quorum-sensing signals. At high cell densities, quorum sensing in V. cholerae invokes a series of signal transduction pathways in order to activate the expression of the master regulator HapR, which then represses the virulence regulon and biofilm-related genes and activates protease production. In this study, we identified a transcriptional regulator, VqmA (VCA1078), that activates hapR expression at low cell densities. Under in vitro inducing conditions, constitutive expression of VqmA represses the virulence regulon in a HapR-dependent manner. VqmA increases hapR transcription as measured by the activity of the hapR-lacZ reporter, and it increases HapR production as measured by Western blotting. Using a heterogenous luxCDABE cosmid, we found that VqmA stimulates quorum-sensing regulation at lower cell densities and that this stimulation bypasses the known LuxO-small-RNA regulatory circuits. Furthermore, we showed that VqmA regulates hapR transcription directly by binding to its promoter region and that expression of vqmA is cell density dependent and autoregulated. The physiological role of VqmA is also discussed.

Human Plasma Gelsolin Inhibits Cellular Responses to Platelet Activating Factor (PAF).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3568-3568
Author(s):  
Teresia A. Magnuson-Osborn ◽  
Claes Dahlgren ◽  
John H. Hartwig ◽  
Thomas P. Stossel
Keyword(s):  
Platelet Activating Factor ◽  
Actin Binding ◽  
Major Surgery ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Cellular Activation ◽  
Blood Concentrations ◽  
Plasma Gelsolin ◽  
Molar Excess

Abstract Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform named plasma gelsolin (pGSN). Relatively high (250 mg /L) blood concentrations of pGSN decrease in response to trauma, major surgery, sepsis, burns, ionizing radiation, and hyperoxia. Depletion of pGSN to a critical (~20%) level precedes and predicts complications of primary injuries such as lung permeability changes, ARDS, assisted ventilation and death. Administration of recombinant pGSN ameliorates such complications and reduces mortality in animal models. A proposed mechanism for pGSN’s protective effects is that it inhibits inflammatory mediators generated during primary injuries, since pGSN binds bioactive mediators, including lysophospatidic acid (LPA) and endotoxin in vitro. Because of its structural similarity we hypothesized that plasma gelsolin binds also to the potent lipid mediator platelet activating factor (PAF) and report here on the inhibition of PAF-induced cellular activation. Recombinant pGSN inhibited PAF-induced P-selectin up-regulation by human platelets as measured by flow cytometry. A ten- to 40-fold molar excess (0.5–20 μM) of pGSN over PAF inhibits P-selectin expression by 40 to 80%. The concentrations of plasma gelsolin used approximate the ~2–3 μM concentrations in plasma, and the molar excess of pGSN over PAF is probably greater in biological systems, where PAF has nanomolar affinity for its receptor. pGSN also inhibited PAF-induced superoxide anion (O2-) production (measured by chemiluminescence) of human neutrophils (PMN) in a concentration-dependent manner. The inhibition was up to 80% at a concentration of 10 μM (tenfold molar excess over PAF). A phospholipid-binding peptide derived from pGSN (QRLFQVKGRR) also inhibited PAF-mediated O2- generation by PMN. The inhibition was 65% at a 1:1 molar ratio (1 μM). In conclusion pGSN interferes with PAF-induced cellular activation in vitro, suggesting a mechanism for the protective role of plasma gelsolin that has been observed in vivo.

Activation of Nitric Oxide Release and Oxidative Metabolism by Leukotrienes B4, C4, and D4 in Human Polymorphonuclear Leukocytes

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1399-1405 ◽  
Author(s):  
Gerd Lärfars ◽  
Frédérique Lantoine ◽  
Marie-Aude Devynck ◽  
Jan Palmblad ◽  
Hans Gyllenhammar
Keyword(s):  
Nitric Oxide ◽  
Rank Order ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Kinetic Properties ◽  
No Production ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cysteinyl Leukotrienes ◽  
Mediators Of Inflammation

Abstract Because arachidonate metabolites are potent mediators of inflammation, we have studied the effects of leukotriene B4(LTB4) and the cysteinyl leukotrienes C4 and D4 (LTC4 and LTD4) on the release of nitric oxide (NO), in vitro, by human polymorphonuclear granulocytes (PMN). Two independent and highly sensitive real-time methods were used for these studies, ie, the NO-dependent oxidation of oxyhemoglobin (HbO2) to methemoglobin and a NO-sensitive microelectrode. When activated with LTB4, LTC4, or LTD4, but not with other lipoxygenase products such as 5S-HETE, 5-oxo-ETE or 5S,12S-diHETE, PMN produced NO in a stimulus- and concentration-dependent manner. The rank order of potency was LTB4 = LTC4 > LTD4, corresponding to 232 ± 50 pmol of NO/106 PMN for 100 nmol/L LTB4 after 30 minutes. The kinetic properties of the responses were similar for all three leukotrienes with a maximum response at 13 ± 3 minutes. Cysteinyl leukotriene and LTB4 antagonists inhibited the agonist-induced NO production by 70%, and treatment with Bordetella pertussis toxin, or chelation of cytosolic Ca2+, [Ca2+]i, also efficiently inhibited this response. In contrast, treatment of PMN with cytochalasin B (5 μg/mL) enhanced the LTB4-induced NO formation by 86%. Thus, this is the first demonstration that the cysteinyl leukotrienes LTC4 and LTD4, as well as LTB4, activate NO release from human PMN by surface receptor, G-protein and [Ca2+]i-dependent mechanisms. This effect differs from activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, for which only LTB4is an activator.

scholarly journals UV cross-linking identifies four polypeptides that require the TATA box to bind to the Drosophila hsp70 promoter.

1990 ◽  
Vol 10 (8) ◽  
pp. 4233-4238 ◽  
Author(s):  
D S Gilmour ◽  
T J Dietz ◽  
S C Elgin
Keyword(s):  
Specific Protein ◽  
Cross Linking ◽  
Dependent Manner ◽  
Hsp70 Promoter ◽  
Intimate Contact ◽  
Nuclear Extracts ◽  
Multicomponent Complex ◽  
Tata Sequence ◽  
Drosophila Embryos

A protein fraction that requires the TATA sequence to bind to the hsp70 promoter has been partially purified from nuclear extracts of Drosophila embryos. This TATA factor produces a large DNase I footprint that extends from -44 to +35 on the promoter. A mutation that changes TATA to TATG interferes both with the binding of this complex and with the transcription of the hsp70 promoter in vitro, indicating that this interaction is important for transcriptional activity. Using a highly specific protein-DNA cross-linking assay, we have identified four polypeptides that require the TATA sequence to bind to the hsp70 promoter. Polypeptides of 26 and 42 kilodaltons are in intimate contact with the TATA sequence. Polypeptides of 150 and 60 kilodaltons interact within the region from +24 to +47 in a TATA-dependent manner. Both the extended footprint and the polypeptides identified by UV cross-linking indicate that the Drosophila TATA factor is a multicomponent complex.

scholarly journals Protein polyglutamylation catalyzed by the bacterial Calmodulin-dependent pseudokinase SidJ

2019 ◽  
Author(s):  
Alan Sulpizio ◽  
Marena E. Minelli ◽  
Min Wan ◽  
Paul D. Burrowes ◽  
Xiaochun Wu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Ubiquitin Ligase ◽  
Legionella Pneumophila ◽  
Biochemical Analysis ◽  
Kinase Activity ◽  
Effector Protein ◽  
Dependent Manner ◽  
Human And Mouse

AbstractPseudokinases are considered to be the inactive counterparts of conventional protein kinases and comprise approximately 10% of the human and mouse kinomes. Here we report the crystal structure of theLegionella pneumophilaeffector protein, SidJ, in complex with the eukaryotic Ca2+-binding regulator, Calmodulin (CaM). The structure reveals that SidJ contains a protein kinase-like fold domain, which retains a majority of the characteristic kinase catalytic motifs. However, SidJ fails to demonstrate kinase activity. Instead, mass spectrometry and in vitro biochemical analysis demonstrate that SidJ modifies anotherLegionellaeffector SdeA, an unconventional phosphoribosyl ubiquitin ligase, by adding glutamate molecules to a specific residue of SdeA in a CaM-dependent manner. Furthermore, we show that SidJ-mediated polyglutamylation suppresses the ADP-ribosylation activity. Our work further implies that some pseudokinases may possess ATP-dependent activities other than conventional phosphorylation.

scholarly journals Potential cardioprotective peptides generated in Spanish dry-cured ham

2019 ◽  
Vol 6 ◽  
Author(s):  
Marta Gallego ◽  
Leticia Mora ◽  
Fidel Toldrá
Keyword(s):  
Cardiovascular Health ◽  
Platelet Activating Factor ◽  
Developed Countries ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Angiotensin I Converting Enzyme ◽  
Lipoxygenase Inhibition ◽  
Dry Cured Ham ◽  
Anti Inflammatory

Food-derived bioactive peptides are promising compounds for the prevention and treatment of cardiovascular diseases, the main cause of mortality in developed countries. The aim of this work was to determine the in vitro anti-inflammatory, antioxidant, and angiotensin I-converting enzyme (ACE-I) inhibitory activities of twenty-four peptides that were identified in Spanish dry-cured hams. For the first time, some peptides such as PSNPP, HCNKKYRSEM and FNMPLTIRITPGSKA showed anti-inflammatory activity expressed as platelet-activating factor-acetylhydrolase, autotaxin, and lipoxygenase inhibition. Peptides MDPKYR and TKYRVP were the strongest antioxidants, whereas GGVPGG, TKYRVP, and HCNKKYRSEM showed the highest ACE-I inhibitory activity. Additionally, several peptides such as KPVAAP, MDPKYR, TKYRVP, and HCNKKYRSEM presented more than one of the assayed activities, increasing their health-enhancing potential. More studies are needed to evaluate the bioavailability of such peptides and their in vivo effect. This would contribute to consider dry-cured ham as a source of peptides beneficial for cardiovascular health.

Vasoactive side effects of intravenous immunoglobulin preparations in a rat model and their treatment with recombinant platelet-activating factor acetylhydrolase

Blood ◽  
2000 ◽  
Vol 95 (5) ◽  
pp. 1856-1861 ◽  
Author(s):  
Wim K. Bleeker ◽  
Jessica L. Teeling ◽  
Arthur J. Verhoeven ◽  
Gemma M. M. Rigter ◽  
Jacques Agterberg ◽  
...  
Keyword(s):  
Side Effects ◽  
Intravenous Immunoglobulin ◽  
Rat Model ◽  
Platelet Activating Factor ◽  
Human Neutrophils ◽  
Ivig Infusion ◽  
Platelet Activating Factor Acetylhydrolase ◽  
Paf Acetylhydrolase ◽  
Immunoglobulin Preparations

Previously, we observed in a rat model that intravenous administration of intramuscular immunoglobulin preparations induced a long-lasting hypotension, which appeared to be associated with the presence of IgG polymers and dimers in the preparations, but unrelated to complement activation. We found evidence that this hypotensive response is mediated by platelet-activating factor (PAF) produced by macrophages. In this study, we compared the vasoactive effects of 16 intravenous immunoglobulin (IVIG) products from 10 different manufacturers, in anesthetized rats. Eight of the IVIG preparations showed no hypotensive effects (less than 15% decrease), whereas the other 8 had relatively strong effects (15%-50% decrease). The hypotensive effects correlated with the IgG dimer content of the preparations. Pretreatment of the rats with recombinant PAF acetylhydrolase completely prevented the hypotensive reaction on IVIG infusion, and administration after the onset of hypotension resulted in normalization of the blood pressure. We also observed PAF production on in vitro incubation of human neutrophils with IVIG, which could be blocked by anti-Fcγ receptor antibodies. This indicates that induction of PAF generation may also occur in a human system. Our findings support the hypothesis that the clinical side effects of IVIG in patients may be caused by macrophage and neutrophil activation through interaction of IgG dimers with Fcγ receptors. Because phagocyte activation may also lead to the release of other inflammatory mediators, recombinant PAF acetylhydrolase (rPAF-AH) provides a useful tool to determine whether PAF plays a role in the clinical side effects of IVIG. If so, rPAF-AH can be used for the treatment of those adverse reactions.

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