| 1. |
- Fu, Huamei, 1979, et al.
(författare)
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The two neutrophil members of the formylpeptide receptor family activate the NADPH-oxidase through signals that differ in sensitivity to a gelsolin derived phosphoinositide-binding peptide
- 2004
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Ingår i: BMC cell biology. - : Springer Science and Business Media LLC. - 1471-2121. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The formylpeptide receptor family members FPR and FPRL1, expressed in myeloid phagocytes, belong to the G-protein coupled seven transmembrane receptor family (GPCRs). They share a high degree of sequence similarity, particularly in the cytoplasmic domains involved in intracellular signaling. The established model of cell activation through GPCRs states that the receptors isomerize from an inactive to an active state upon ligand binding, and this receptor transformation subsequently activates the signal transducing G-protein. Accordingly, the activation of human neutrophil FPR and FPRL1 induces identical, pertussis toxin-sensitive functional responses and a transient increase in intracellular calcium is followed by a secretory response leading to mobilization of receptors from intracellular stores, as well as a release of reactive oxygen metabolites. RESULTS: We report that a cell permeable ten amino acid peptide (PBP10) derived from the phosphatidylinositol 4,5-bisphosphate (PIP2) binding region of gelsolin (an uncapper of actin filaments) blocks granule mobilization as well as secretion of oxygen radicals. The inhibitory effect of PBP10 is, however, receptor specific and affects the FPRL1-, but not the FPR-, induced cellular response. The transient rise in intracellular calcium induced by the active receptors is not affected by PBP10, suggesting that the blockage occurs in a parallel, novel signaling pathway used by FPRL1 to induce oxygen radical production and secretion. Also the FPR can activate neutrophils through a PBP10-sensitive signaling pathway, but this signal is normally blocked by the cytoskeleton. CONCLUSIONS: This study demonstrates that the two very closely related chemoattractant receptors, FPR and FPRL1, use distinct signaling pathways in activation of human neutrophils. The PIP2-binding peptide PBP10 selectively inhibits FPRL1-mediated superoxide production and granule mobilization. Furthermore, the activity of this novel PBP10 sensitive pathway in neutrophils is modulated by the actin cytoskeleton network.
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| 2. |
- Karlsson, Anna, 1967, et al.
(författare)
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Different glycosphingolipid composition in human neutrophil subcellular compartments.
- 2001
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Ingår i: Glycoconjugate journal. - 0282-0080. ; 18:3, s. 231-43
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Tidskriftsartikel (refereegranskat)abstract
- The binding of a number of carbohydrate-recognizing ligands to glycosphingolipids and polyglycosylceramides of human neutrophil subcellular fractions (plasma membranes/secretory vesicles of resting and ionomycin-stimulated cells, specific and azurophil granules) was examined using the chromatogram binding assay. Several organelle-related differences in glycosphingolipid content were observed. The most prominent difference was a decreased content of the GM3 ganglioside in plasma membranes of activated neutrophils. Gangliosides recognized by anti-VIM-2 antibodies were detected mainly in the acid fractions of azurophil and specific granules. Slow-migrating gangliosides and polyglycosylceramides with Helicobacter pylori-binding activity were found in all acid fractions. A non-acid triglycosylceramide, recognized by Gal(alpha)4Gal-binding Escherichia coli, was detected in the plasma membrane/secretory vesicles but not in the azurophil and specific granules. Although no defined roles of glycosphingolipids have yet been conclusively established with respect to neutrophil function, the fact that many of the identified glycosphingolipids are stored in granules, is in agreement with their role as receptor structures that are exposed on the neutrophil cell surface upon fusion of granules with the plasma membrane. Accordingly, we show that neutrophil granules store specific carbohydrate epitopes that are upregulated to the plasma membrane upon cell activation.
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| 3. |
- Almkvist, Jenny, 1971, et al.
(författare)
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Activation of the neutrophil nicotinamide adenine dinucleotide phosphate oxidase by galectin-1.
- 2002
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - 0022-1767. ; 168:8, s. 4034-4041
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Tidskriftsartikel (refereegranskat)abstract
- Galectins are a group of lactose-binding proteins widely distributed in nature. Twelve mammalian galectins have so far been identified, but their functions are to a large extent unknown. In this work we study galectin-1 in its interaction with human neutrophils, with regard to both cell surface binding and activation of the superoxide-producing NADPH-oxidase. We show that galectin-1 is able to activate the neutrophil NADPH-oxidase, provided that the cells have been primed by extravasation from the blood into the tissue, an activation pattern that is similar to that of galectin-3. Using in vitro priming protocols, the galectin-1 responsiveness was found to correlate to granule mobilization and galectin-1 binding to the cells, suggesting the presence of granule-localized receptors that are up-regulated to the cell surface upon priming. By galectin-1 overlay of fractionated neutrophils we identified potential galectin-1 receptor candidates localized in the membranes of the secretory vesicle and gelatinase granules. The binding of galectin-1 and galectin-3 to neutrophil proteins was compared, as were the dose dependencies for activation by the two lectins. The results suggest that, although similarities are found between the two galectins, they appear to activate the NADPH-oxidase using different receptors. In conclusion, galectin-1 appears to have proinflammatory functions, mediated through activation of the neutrophil respiratory burst.
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| 4. |
- Almkvist, Jenny, 1971, et al.
(författare)
-
Lipopolysaccharide-induced gelatinase granule mobilization primes neutrophils for activation by galectin-3 and formylmethionyl-Leu-Phe.
- 2001
-
Ingår i: Infection and immunity. - 0019-9567 .- 1098-5522. ; 69:2, s. 832-7
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Tidskriftsartikel (refereegranskat)abstract
- We have earlier shown that galectin-3, a lactose-binding mammalian lectin that is secreted from activated macrophages, basophils, and mast cells, induces activation of the NADPH oxidase in exudated but not in peripheral blood neutrophils (A. Karlsson, P. Follin, H. Leffler, and C. Dahlgren, Blood 91:3430-3438, 1998). The alteration in responsiveness occurring during extravasation correlated with mobilization of the gelatinase and/or specific granules to the cell surface, indicating a role for mobilizable galectin-3 receptors. In this study we have investigated galectin-3-induced NADPH oxidase activation, measured as superoxide production, in lipopolysaccharide (LPS)-primed neutrophils. Upon galectin-3 challenge, the LPS-primed cells produced superoxide, both extracellularly and intracellularly. A primed extracellular response to formylmethionyl-Leu-Phe (fMLF) was also achieved. The exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the cell surface was markedly increased after LPS treatment, indicating that granule fusion with the plasma membrane had occurred. Further assessment of specific markers for neutrophil granules showed that the LPS treatment had mobilized the gelatinase granules but only a minor fraction of the specific granules. We thus suggest that the mechanism behind LPS priming lies at the level of granule (receptor) mobilization for galectin-3 as well as for fMLF.
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| 5. |
- Almkvist, Jenny, 1971, et al.
(författare)
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Newcastle disease virus neuraminidase primes neutrophils for stimulation by galectin-3 and formyl-Met-Leu-Phe
- 2004
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Ingår i: Experimental cell research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 298:1, s. 74-82
-
Tidskriftsartikel (refereegranskat)abstract
- Human neutrophils are activated by the beta-galactoside-binding lectin galectin-3, provided that the cells are primed by in vivo extravasation or by in vitro preactivation with, for example, LPS. Removal of terminal sialic acid can change neutrophil functionality and responsiveness due to exposure of underlying glycoconjugate receptors or change in surface charge. Here, we investigated whether such alteration of the cell surface carbohydrate composition can alter the responsiveness of the cells to galectin-3. Neutrophils were treated with neuraminidases (NA) of different origins: Clostridium perfringens (CP), Salmonella typhimurium, Vibrio cholerae, and Newcastle disease virus (NDV). In the presence of NDV-NA, but no other NA, the otherwise non-responding neutrophils responded readily to galectin-3 by activation of the NADPH-oxidase. The galectin-3 priming effect was inhibited by the sialidase inhibitor 2,3-dehydro-2-deoxy-N-acetyl-neuraminic acid. Earlier studies have shown that priming of the neutrophil response to galectin-3 with, for example, LPS is paralleled by degranulation of intracellular vesicles and granules and upregulation of potential galectin-3 receptors. Also, NDV-NA (but not CP-NA) treatment induced degranulation, shown as an upregulation of complement receptor 3. Since not only the galectin response but also the response to the chemoattractant fMLF was primed, NDV-NA appears to induce a general priming phenomenon, possibly due to receptor upregulation by degranulation.
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| 6. |
- Björk-Eriksson, Thomas, 1960, et al.
(författare)
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Tumor radiosensitivity (SF2) is a prognostic factor for local control in head and neck cancers
- 2000
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Ingår i: Int J Radiat Oncol Biol Phys. - 0360-3016. ; 46:1, s. 13-9
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate prospectively the prognostic value of SF2 for local control and survival in patients undergoing radiation therapy for head and neck cancers. METHODS AND MATERIALS: Following informed consent tumor specimens were obtained from 156 patients with primary carcinomas of the head and neck region. The specimens were assessed for the ability to grow in vitro (colony forming efficiency, CFE) and inherent radiosensitivity measured as the surviving fraction at 2 Gy (SF2) using a soft-agar clonogenic assay. Patients were treated mainly with neoadjuvant chemotherapy plus radiation therapy usually as a combination of accelerated external beam and interstitial radiotherapy. The probabilities of local control and survival were analyzed by univariate, bivariate and Cox multivariate analyses. RESULTS: Successful growth was achieved in 110/156 specimens and SF2 values were obtained from 99/156. Eighty four out of these patients underwent radical treatment. The median SF2 value for the 84 tumors was 0.40. At a mean follow-up time of 25 months (range 7-65) the median SF2 value of tumors from 14 patients who developed local recurrence was 0.53, which was significantly higher than the median of 0.38 for tumors from 70 patients without local recurrence (p = 0.015). Tumor SF2 was a significant prognostic factor for local control (p = 0.036), but not for overall survival (p = 0.20). Tumor SF2 was an independent prognostic factor for local control within bivariate and Cox multivariate analyses. CONCLUSIONS: This study has shown that tumor radiosensitivity measured as SF2 is a significant prognostic factor for local control in head and neck cancers.
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| 7. |
- Bylund, Johan, 1975, et al.
(författare)
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Cytochalasin B triggers a novel pertussis toxin sensitive pathway in TNF-alpha primed neutrophils
- 2004
-
Ingår i: BMC cell biology. - 1471-2121. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cytochalasin B does not directly activate the oxygen-radical-producing NADPH oxidase activity of neutrophils but transfers desensitized G-protein coupled receptors (GPCR) into an active signaling state by uncoupling GCPR from the cytoskeleton. The receptor uncoupling results in respiratory burst activity when signals generated by reactivated formyl peptide receptors trigger the NADPH-oxidase to produce superoxide anions. RESULTS: Tumor necrosis factor alpha (TNF-alpha) primes neutrophils for subsequent activation by cytochalasin B. Pretreatment with TNF-alpha induced mobilization of receptor-storing neutrophil organelles, suggesting that receptor up-regulation significantly contributes to the response, but the receptor mobilization was not sufficient for induction of the cytochalasin B sensitive state. The TNF-alpha primed state resembled that of the desensitized non-signaling state of agonist-occupied neutrophil formyl peptide receptors. The fact that the TNF-alpha primed, cytochalasin B-triggered activation process was pertussis toxin sensitive suggests that the activation process involves a GPCR. Based on desensitization experiments the unidentified receptor was found to be distinct from the C5a receptor as well as the formyl peptide receptor family members FPR and FPRL1. Based on the fact the occupied and desensitized receptors for interleukin-8 and platelet activating factor could not be reactivated by cytochalasin B, also these could be excluded as receptor candidates involved in the TNF-alpha primed state. CONCLUSIONS: The TNF-alpha-induced priming signals could possibly trigger a release of an endogenous GPCR-agonist, amplifying the response to the receptor-uncoupling effect of cytochalasin B. However, no such substance could be found, suggesting that TNF-alpha can transfer G-protein coupled receptors to a signaling state independently of agonist binding.
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| 8. |
- Bylund, Johan, 1975, et al.
(författare)
-
Lipopolysaccharide-induced granule mobilization and priming of the neutrophil response to Helicobacter pylori peptide Hp(2-20), which activates formyl peptide receptor-like 1
- 2002
-
Ingår i: Infect Immun. ; 70:6, s. 2908-14
-
Tidskriftsartikel (refereegranskat)abstract
- The cecropin-like bactericidal peptide Hp(2-20) from Helicobacter pylori induces activation of the NADPH oxidase in human neutrophils via formyl peptide receptor-like 1 (FPRL1) (J. Bylund, T. Christophe, F. Boulay, T. Nystrom, A. Karlsson, and C. Dahlgren, Antimicrob. Agents Chemother. 45:1700-1704, 2001). Here we investigated the ability of bacterial lipopolysaccharide (LPS) to prime this response. Neutrophils treated with LPS for 30 min at 37 degrees C produced substantially more superoxide anion than control cells upon stimulation with Hp(2-20). Hence, LPS primed the cells for subsequent stimulation through FPRL1. To study the molecular background of this priming phenomenon, we measured the degrees of granule mobilization and concomitant receptor upregulation to the cell surface in LPS-treated cells. Exposure of complement receptors 1 and 3 as well as the formyl peptide receptor (FPR) was markedly increased after LPS treatment. Since approximately 60% of the gelatinase granules were mobilized while the specific granules were retained, we hypothesized that the gelatinase granules were potential stores of FPRL1. The presence of FPRL1 mainly in the gelatinase granules was confirmed by Western blotting of subcellular fractions of resting neutrophils. These results suggest that the mechanism behind the LPS-induced priming of FPRL1-mediated responses lies at the level of granule (receptor) mobilization.
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| 9. |
- Bylund, Johan, 1975, et al.
(författare)
-
Proinflammatory activity of a cecropin-like antibacterial peptide from Helicobacter pylori
- 2001
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Ingår i: Antimicrob Agents Chemother. ; 45:6, s. 1700-4
-
Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori, the bacterial pathogen associated with gastritis and peptic ulcers, is highly successful in establishing infection in the human gastric mucosa, a process typically associated with massive infiltration of inflammatory cells. Colonization of the mucosa is suggested to be facilitated by H. pylori-produced cecropin-like peptides with antibacterial properties, giving the microbe a competitive advantage over other bacteria. We show that a cecropin-like antibacterial peptide from H. pylori, Hp(2-20), not only has a potent bactericidal effect but also induces proinflammatory activities in human neutrophils, e.g., upregulation of integrins (Mac-1), induction of chemotaxis, and activation of the oxygen radical producing NADPH-oxidase. Furthermore, we show that these effects are mediated through binding of Hp(2-20) to the promiscuous, G-protein-linked lipoxin A(4) receptor-formyl peptide-like receptor 1.
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| 10. |
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| 11. |
- Christophe, T, et al.
(författare)
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Phagocyte activation by Trp-Lys-Tyr-Met-Val-Met, acting through FPRL1/LXA4R, is not affected by lipoxin A4.
- 2002
-
Ingår i: Scandinavian journal of immunology. - 0300-9475. ; 56:5, s. 470-6
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Tidskriftsartikel (refereegranskat)abstract
- Lipoxin A4 (LXA4) has been shown to bind to the leucocyte formyl peptide receptor (FPR) homologue, FPRL1, without triggering the biological activities induced by other FPRL1 agonists. We investigated the direct effect of LXA4 as well as the effect on agonist-induced biological responses using transfected HL-60 cells expressing FPR, FPRL1 or FPRL2. LXA4 neither induced an intracellular rise in calcium in these transfectants nor affected the response induced by the peptide Trp-Lys-Tyr-Met-Val-Met (WKYMVM), an agonist that activates cells through FPRL1 and -2. Both agonists induced Erk-2 activation; however, the eicosanoid-induced activity was independent of FPRL1 and FPRL2. Moreover, LXA4 was unable to trigger neutrophil upregulation of complement receptor 3 and respiratory burst, and it had no effect on the responses induced by triggering with WKYMVM. We conclude that LXA4 is unable to affect the WKYMVM-induced signalling through FPRL1 and suggest that it acts through a receptor different from FPRL1.
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| 12. |
- Christophe, T, et al.
(författare)
-
The synthetic peptide Trp-Lys-Tyr-Met-Val-Met-NH2 specifically activates neutrophils through FPRL1/lipoxin A4 receptors and is an agonist for the orphan monocyte-expressed chemoattractant receptor FPRL2.
- 2001
-
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 276:24, s. 21585-93
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils express the G protein-coupled N-formyl peptide receptor (FPR) and its homologue FPRL1, whereas monocytes express FPR, FPRL1, and FPRL2, an orphan receptor sharing 83% amino acid identity with FPRL1. FPRL1 is a promiscuous receptor activated by serum amyloid A and by different synthetic peptides, including the hexapeptide Trp-Lys-Tyr-Met-Val-d-Met-NH(2) (WKYMVm). By measuring calcium flux in HL-60 cells transfected with FPR, FPRL1, or FPRL2, we show that WKYMVm activated all three receptors, whereas the l-conformer WKYMVM activated exclusively FPRL1 and FPRL2. The functionality of FPRL2 was further assessed by the ability of HL-60-FPRL2 cells to migrate toward nanomolar concentrations of hexapeptides. The half-maximal effective concentrations of WKYMVM for calcium mobilization in HL-60-FPRL1 and HL-60-FPRL2 cells were 2 and 80 nm, respectively. Those of WKYMVm were 75 pm and 3 nm. The tritiated peptide WK[3,5-(3)H(2)]YMVM bound to FPRL1 (K(D) approximately 160 nm), but not to FPR. The two conformers similarly inhibited binding of (125)I-labeled WKYMVm to FPRL2-expressing cells (IC(50) approximately 2.5-3 micrometer). Metabolic labeling with orthophosphoric acid revealed that FPRL1 was differentially phosphorylated upon addition of the l- or d-conformer, indicating that it induced different conformational changes. In contrast to FPRL1, FPRL2 was already phosphorylated in the absence of agonist and not evenly distributed in the plasma membrane of unstimulated cells. However, both receptors were internalized upon addition of either of the two conformers. Taken together, the results indicate that neutrophils are activated by WKYMVM through FPRL1 and that FPRL2 is a chemotactic receptor transducing signals in myeloid cells.
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| 13. |
- Dahlgren, Claes, 1949, et al.
(författare)
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Ionomycin-induced neutrophil NADPH oxidase activity is selectively inhibited by the serine protease inhibitor diisopropyl fluorophosphate.
- 2002
-
Ingår i: Antioxidants & redox signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 4:1, s. 17-25
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Tidskriftsartikel (refereegranskat)abstract
- The calcium-specific ionophore ionomycin triggers neutrophils to activate their NADPH oxidase and generate reactive oxygen species. This activation is restricted to intracellular sites and involves the neutrophil granules. Cells that have experienced an ionomycin-induced rise in intracellular calcium will also mobilize their intracellular granules and are primed to subsequent challenge with the chemoattractant formylmethionyl-leucyl-phenylalanine (fMLF), but have lost their ability to become desensitized to the same agonist. We have investigated the involvement of serine proteases in the calcium-induced effector functions using the inhibitor diisopropyl fluorophosphate (DFP). The ionomycin-induced NADPH oxidase activity was abrogated by the protease inhibitor, whereas the activity induced by fMLF was unaffected. The DFP-dependent inhibition was restricted to the NADPH oxidase activity, as all other ionomycin-induced cellular activities were largely unaffected. We thus suggest that a serine protease is of importance for the calcium ionophore-induced signal(s) to reach and activate the dormant NADPH oxidase in the neutrophil granules.
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| 14. |
- Dahlgren, Claes, 1949, et al.
(författare)
-
Neutrophil secretory vesicles are the intracellular reservoir for GPI-80, a protein with adhesion-regulating potential.
- 2001
-
Ingår i: Journal of leukocyte biology. - 0741-5400. ; 69:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- The subcellular localization of GPI-80, a novel, adhesion-regulating protein, was investigated in human neutrophils. Surface expression of GPI-80 was determined by FACS analysis as well as by the ability for phospholipase C to cleave the protein from the cell surface. Increasing amounts of GPI-80 were exposed on the cell surface after weak stimulation with the chemoattractant fMLF, suggesting that the protein can be translocated to the plasma membrane from intracellular stores. By subcellular fractionation of the neutrophils, GPI-80 was defined as a component of a light membrane fraction, containing secretory vesicles and plasma membranes, and it was absent from the neutrophil granule fractions. Separation of the plasma membranes from the secretory vesicles by flotation gradient fractionation confirmed that the GPI-80 was localized in the mobilizable secretory vesicles by approximately 50%, and the rest was plasma membrane-bound. Thus, we identify secretory vesicles as the reservoir of GPI-80 from which it may translocate to the plasma membrane after weak stimulation of the cells.
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| 15. |
- Dahlgren, Claes, 1949, et al.
(författare)
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The synthetic chemoattractant Trp-Lys-Tyr-Met-Val-DMet activates neutrophils preferentially through the lipoxin A(4) receptor.
- 2000
-
Ingår i: Blood. - 0006-4971. ; 95:5, s. 1810-8
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Tidskriftsartikel (refereegranskat)abstract
- A D-methionine-containing peptide, Trp-Lys-Tyr-Met-Val-D-Met-NH(2) (WKYMVm), featuring a unique receptor specificity was investigated with respect to its ability to activate neutrophil effector functions. The peptide was found to be more potent than the N-formylated peptide N-formyl-Met-Leu-Phe (fMLF) at inducing neutrophil chemotaxis, mobilization of neutrophil complement receptor 3 (CR3), and activation of the neutrophil NADPH-oxidase. The fact that binding of fML[(3)H]F was inhibited by both fMLF and WKYMVm suggests that N-formyl peptide receptor (FPR) is shared by these peptides. However, the neutrophil response induced by the WKYMVm peptide was insensitive to the fMLF antagonists, cyclosporin H, and Boc-FLFLF that specifically block the function of the FPR. These results suggest that even though WKYMVm may bind FPR the cells are activated preferentially through a receptor distinct from the FPR. Using transfected HL-60 cells expressing either the FPR or its neutrophil homologue FPRL1, also referred to as LXA(4)R because it has been shown to bind lipoxin A(4), we show that WKYMVm is about 300-fold more active at mobilizing intracellular calcium through FPRL1 than through FPR. The WKYMVm activates FPRL1-expressing cells in a cyclosporin H-independent manner with an EC(50 )of around 75 pmol/L, whereas it activates FPR-expressing cells with an EC(50 )of around 25 nmol/L. The observation that exudated cells are primed in their response to WKYMVm suggests that FPRL1/LXA(4)R like FPR is stored in mobilizable organelles. (Blood. 2000;95:1810-1818)
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| 16. |
- Fu, Huamei, 1979, et al.
(författare)
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The mechanism for activation of the neutrophil NADPH-oxidase by the peptides formyl-Met-Leu-Phe and Trp-Lys-Tyr-Met-Val-Met differs from that for interleukin-8
- 2004
-
Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 112:2, s. 201-10
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophil chemotaxis has been shown to be regulated by two different signalling pathways that allow strong chemoattractants, such as bacterial-derived formylated peptides, to dominate over endogenous attractants, such as interleukin-8 (IL-8). Here we show that triggering of the formyl peptide receptor (FPR) with f-Met-Leu-Phe (fMLF) substantially reduced the neutrophil superoxide production induced by activation of the CXC receptors with IL-8. When the order of agonists was reversed, the cells were primed in their response to fMLF, suggesting that the signalling hierarchy between strong, so-called end-type (i.e. fMLF) and weak or intermediate-type (i.e. IL-8) chemoattractants, is also operating during activation of the NADPH-oxidase. The same result was obtained when fMLF was replaced with the hexapeptide, WKYMVM, specific for the formyl peptide-like receptor 1 (FPRL1). There were additional differences between the agonist receptor pairs fMLF/FPR, WKYMVM/FPRL1 and IL-8/CXCR. In contrast to FPR and FPRL1, no reserve pool of CXCR was present in subcellular granules and it was impossible to prime the oxidative response transduced through CXCR by the addition of priming agents such as tumour necrosis factor-alpha and platelet-activating factor. Moreover, the cytoskeleton-disrupting substance, cytochalasin B, had no effect either on IL-8-triggered oxidase activation or on CXCR reactivation. A pertussis toxin-sensitive G-protein is involved in signalling mediated through both FPR and CXCR, and the signalling cascades include a transient intracellular calcium increase, as well as downstream p38 MAPK and phosphoinositide 3-kinase activation. The data presented in this study provide support for two different signalling pathways to the neutrophil NADPH-oxidase, used by ligand binding to FPR/FPRL1 or CXCR, respectively.
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| 17. |
- Fäldt, Jenny, 1971, et al.
(författare)
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Priming of human neutrophils by mycobacterial lipoarabinomannans: role of granule mobilisation.
- 2001
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Ingår i: Microbes and infection. - 1286-4579. ; 3:13, s. 1101-9
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Tidskriftsartikel (refereegranskat)abstract
- Lipoarabinomannans (LAMs) from mycobacteria were investigated concerning their effect on human neutrophils. Two types of LAM, the mannose-capped ManLAM from the virulent Mycobacterium tuberculosis H37Rv and the mannose-lacking AraLAM from a rapidly growing mycobacterial strain were used. Neither AraLAM nor ManLAM induced any significant direct activation of the NADPH-oxidase. Both LAMs, however, primed the neutrophils so that subsequent stimulation with the peptide chemoattractants fMet-Leu-Phe (fMLF), Trp-Lys-Tyr-Met-Val-DMet (WKYMVm) and the mammalian lactose-binding lectin galectin-3 resulted in a markedly enhanced oxidative response. The LAM-induced priming was accompanied by an increased exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the neutrophil surface, suggesting that the enhanced oxidative response could be due to upregulation of receptors on the cell surface as a result of granule mobilisation. Since LAM-primed neutrophils released 65% of the cell content of gelatinase but showed no increased release of vitamin B(12)-binding protein, mobilisation of the gelatinase granules rather than the specific granules is concluded to be responsible for the priming effects. This is in agreement with the subcellular localisation of receptors for fMLF, WKYMVm, as well as galectin-3, which are stored in the secretory vesicles and gelatinase granules. The priming effect appeared very similar to that of Escherichia coli lipopolysaccharide, and since no differences in activity could be detected between AraLAM and ManLAM, we hypothesize that the lipid anchor of the LAM is responsible for the priming effects.
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| 18. |
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| 19. |
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| 20. |
- Hydén, Lars-Christer, et al.
(författare)
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När olikhet blir problem handikappforskning, kontext och social interaktion
- 2003
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Ingår i: socialmedicinsk tidskrift. ; 10:4, s. 319-333
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- I artikeln argumenterar författarna för försök att inom handkappforskningen gå utöver traditioner av att den medicinska kroppsuppfattningen är ett bärande element i analyser av det sociala.
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| 21. |
- Juliusson, Gunnar, 1954-, et al.
(författare)
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Adjusted conditioning for allogeneic transplantation in a single center setting : Mixed chimerism heralds relapse
- 2003
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 44:4, s. 669-679
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Tidskriftsartikel (refereegranskat)abstract
- The role of mixed chimerism on subsequent relapse was prospectively evaluated in an allotransplant program. Sixty-six patients with median age of 54 and mainly high-risk hematologic disease and/or solid tumors had individually adjusted non-myeloablative conditioning. Thirty-nine donors were siblings and 27 unrelated. Frequent chimerism analyses supported immune manipulation including donor lymphocyte infusions. The need for transfusions, iv fluids, and antibiotics, and weight loss was less than in a control cohort. Most patients had immediate full and consistent donor chimerism, one-third required immune manipulation. Eight of ten evaluable CML patients were BCR/ABL-negative at days 14-58 post-transplant. Mixed chimerism frequently preceded relapse, and the relapse rate was 38% in 26 patients with mixed chimerism vs. 11% among 35 with consistent full donor chimerism (p = 0.015). The current transplant- and disease-related mortality were 11 and 9%, respectively, among 35 non-high-risk patients, and 35 and 10% for 29 high-risk patients with hematologic malignancy. With a median follow-up of 15 months the 2-year overall survival is 73% for non-high-risk, and 46% for high-risk patients. Adjusted conditioning reduces early toxicity and resource requirements without impairing tumor control, probably due to a rapid establishment of the graft-versus-cancer effect. Mixed chimerism heralded relapse, and tumor-related mortality is not greater with adjusted than with conventional conditioning.
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| 22. |
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| 23. |
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| 24. |
- Karlsson, Anna, 1967, et al.
(författare)
-
Assembly and activation of the neutrophil NADPH oxidase in granule membranes.
- 2002
-
Ingår i: Antioxidants & redox signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 4:1, s. 49-60
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Forskningsöversikt (refereegranskat)abstract
- Phagocyte activation is accompanied by assembly of an NADPH oxidase that reduces oxygen to form a number of reactive species. These oxygen radicals can eradicate invading microorganisms, regulate the function of other immune reactive cells, and cause damage to "innocent bystander" cells. It is generally assumed that the NADPH oxidase is activated exclusively in the plasma membrane. In neutrophils, this assumption does not fit with the subcellular localization of the membrane component of the oxidase, which is stored in granule compartments. It has now become increasingly evident that oxidants are also produced in an intracellular compartment that we identify as the specific granules. Myeloperoxidase is stored in another granule subset, the azurophil granules, and participates in the processing of the oxidative metabolites. We suggest that neutrophil activation is accompanied by fusion between azurophil and specific granules, allowing these peroxidase-dependent reactions to take place. The presented data suggest a requisite role for neutrophil oxidants complementing their function as microbial killing agents. Signaling capabilities of the oxidants, affecting for example, the state of protein phosphorylation, regulation of transcription factors, and induction of apoptosis, are discussed.
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| 25. |
- Karlsson, Lena, et al.
(författare)
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Requirements prioritisation: an experiment on exhaustive pair-wise comparisons versus planning game partitioning
- 2004
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Ingår i: 8th Internation Conference on Empirical Assessment in Software Engineering (EASE 2004) Workshop - 26th International Conference on Software Engineering. - 0863414354 ; , s. 145-154
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Konferensbidrag (refereegranskat)abstract
- The process of selecting the right set of requirements for a product release is highly dependent on how well we succeed in prioritising the requirements candidates. There are different techniques available for requirements prioritisation, some more elaborate than others. In order to compare different techniques, a controlled experiment was conducted with the objective of understanding differences regarding time consumption, ease of use, and accuracy. The requirements prioritisation techniques compared in the experiment are the analytical hierarchy process (AHP) and a variation of the planning game (PG), isolated from extreme programming. The subjects were 15 Ph.D. students and one professor, who prioritised mobile phone features using both methods. It was found that the straightforward and intuitive PG was less time consuming, and considered by the subjects as easier to use, and more accurate than AHP
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| 26. |
- Karlsson, Lena, et al.
(författare)
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Simple Is Better? : An Experiment on Requirements Prioritisation
- 2003
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Ingår i: - Lund, Sweden. ; , s. 9-18
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Konferensbidrag (refereegranskat)abstract
- The process of selecting the right set of requirements for a product release is highly dependent on how well we succeed in prioritising the requirements candidates. There are different techniques available for requirements prioritisation, some more elaborate than others. In order to compare different techniques, a controlled experiment was conducted with the objective of understanding differences regarding time consumption, ease of use, and accuracy. The requirements prioritisation techniques compared in the experiment are the Analytical Hierarchy Process (AHP) and a variation of the Planning Game (PG), isolated from Extreme Programming. The subjects were 15 Ph.D. students and one professor, who prioritised mobile phone features using both methods. It was found that the straightforward and intuitive PG was less time consuming, and considered by the subjects as easier to use, and more accurate than AHP.
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Spåhr, H, et al.
(författare)
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Purification and characterization of RNA polymerase II holoenzyme from Schizosaccharomyces pombe.
- 2000
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Ingår i: The Journal of biological chemistry. - : Elsevier BV. - 0021-9258. ; 275:2, s. 1351-6
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Tidskriftsartikel (refereegranskat)abstract
- We have purified the RNA polymerase II holoenzyme from Schizosaccharomyces pombe to near homogeneity. The Mediator complex is considerably smaller than its counterpart in Saccharomyces cerevisiae, containing only nine polypeptides larger than 19 kDa. Five of these Mediator subunits have been identified as the S. pombe homologs to Rgr1, Srb4, Med7, and Nut2 found in S. cerevisiae and the gene product of a previously uncharacterized open reading frame, PMC2, with no clear homologies to any described protein. The presence of Mediator in a S. pombe RNA polymerase II holoenzyme stimulated phosphorylation of the C-terminal domain by TFIIH purified from S. pombe. This stimulation was species-specific, because S. pombe Mediator could not stimulate TFIIH purified from S. cerevisiae. We suggest that the overall structure and mechanism of the Mediator is evolutionary conserved. The subunit composition, however, has evolved to respond properly to physiological signals.
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| 31. |
- Wadelius, Mia, et al.
(författare)
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Warfarin sensitivity related to CYP2C9, CYP3A5, ABCB1 (MDR1) and other factors
- 2004
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Ingår i: The Pharmacogenomics Journal. - : Springer Science and Business Media LLC. - 1470-269X .- 1473-1150. ; 4:1, s. 40-8
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Tidskriftsartikel (refereegranskat)abstract
- The required dose of the oral anticoagulant warfarin varies greatly, and overdosing often leads to bleeding. Warfarin is metabolised by cytochrome P450 enzymes CYP2C9, CYP1A2 and CYP3A. The target cell level of warfarin may be dependent on the efflux pump P-glycoprotein, encoded by the adenosine triphosphate-binding cassette gene ABCB1 (multidrug resistance gene 1). Genetic variability in CYP2C9, CYP3A5 and ABCB1 was analysed in 201 stable warfarin-treated patients using solid-phase minisequencing, pyrosequencing and SNaPshot. CYP2C9 variants, age, weight, concurrent drug treatment and indication for treatment significantly influenced warfarin dosing in these patients, explaining 29% of the variation in dose. CYP3A5 did not affect warfarin dosing. An ABCB1 haplotype containing the exon 26 3435T variant was over-represented among low-dose patients. Thirty-six patients with serious bleeding complications had higher prothrombin time international normalised ratios than 189 warfarin-treated patients without serious bleeding, but there were no significant differences in CYP2C9, CYP3A5 or ABCB1 genotypes and allelic variants.
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