| 1. |
- Fu, Huamei, 1979, et al.
(författare)
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A bactericidal cecropin-A peptide with a stabilized alpha-helical structure possess an increased killing capacity but no proinflammatory activity
- 2004
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Ingår i: Inflammation. - : Springer Science and Business Media LLC. - 0360-3997 .- 1573-2576. ; 28:6, s. 337-43
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Tidskriftsartikel (refereegranskat)abstract
- Antibacterial peptides are part of the innate immune system in a variety of different species including humans. Some of these peptides have also been shown to have effects on immune competent cells such as professional phagocytes. We have recently shown that a cecropin-like peptide from Helicobacter pylori, Hp(2-20), in addition to being bactericidal possesses proinflammatory effects and can recruit and activate neutrophils as well as monocytes. It is well established that cecropins have the ability to adopt amphipathic alpha-helices, which is thought to be required for their bactericidal activity. In this study we show the same structural requirements for Hp(2-20). Breaking the helical structure of Hp(2-20) reduced the antibacterial effect and abolished its proinflammatory activity. A C-terminal truncated cecropin A peptide that highly resembles Hp(2-20) failed to activate neutrophils and computer-based structural simulations revealed a difference between the two peptides in the stability of their helical structures. A hybrid peptide with amino acid substitutions stabilizing the alpha-helical structure of the truncated cecropin A peptide did not introduce any proinflammatory activity; the bactericidal activity was, however, increased. We thus conclude that the proinflammatory effect of Hp(2-20) is a unique sequence-specific feature of the peptide and the ability to adopt a stable amphipathic helix is a necessary but not sufficient criterion for the functional dualism of the peptide.
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| 2. |
- Knudsen, J.F., et al.
(författare)
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The cyclooxygenase-2 inhibitor celecoxib is a potent inhibitor of human carbonic anhydrase II
- 2004
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Ingår i: Inflammation. - : Springer Science and Business Media LLC. - 0360-3997 .- 1573-2576. ; 28:5, s. 285-290
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Tidskriftsartikel (refereegranskat)abstract
- Cyclooxygenase-2 (COX-2) is up-regulated in stromal and inflammatory cells. The inducible COX-2 isoform is expressed during inflammation, in some cancers, and in brain tissue after global and focal ischemia. Tissue acidosis is a dominant factor in inflammation, and contributes to pain and hyperalgesia. Recently, compelling epidemiological and clinical evidence has documented the COX-independent effects of some COX-2 inhibitors (i.e., celecoxib, valdecoxib, and rofecoxib), among these effects are carbonic anhydrase (CA) inhibition. Carbonic anhydrases are zinc metalloenzymes expressed in various cell types, including those of the kidney, where they act as general acid-base catalysts. The kidneys are also known to express the highest concentration of COX-2 messenger ribonucleic acid. Celecoxib, like the prototypic CA inhibitor acetazolamide, is structurally characterized by an unsubstituted sulfonamide moiety. In the present study, we report that celecoxib exhibits the characteristics of a potent CA inhibitor, showing inhibitory human carbonic anhydrase II (hCAII) activity in the nanomolar range. Valdecoxib was relatively less potent. Rofecoxib, which lacks the unsubstituted sulfonamide moiety characteristic of CA inhibitors, showed no significant hCAII inhibitory activity. The current study corroborates our earlier report of structure-activity relationships as predictors of such metabolic events as hyperchloremia, acidosis, and changes in calcium and phosphate disposition, and clinical manifestations associated with CA inhibition reported with celecoxib. These data showing inhibition of hCAII by the unsubstituted sulfonamides celecoxib and valdecoxib, but not by rofecoxib, may have important implications for the elucidation of the mechanisms of action as well as the side effects associated with COX-2 inhibitors. © 2004 Springer Science+Business Media, Inc.
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| 3. |
- Nyhlén, Kristina, 1967-, et al.
(författare)
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Modulation of Cytokine-Induced Production of IL-8 in Vitro by Interferons and Glucocorticosteroids
- 2004
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Ingår i: Inflammation. - 0360-3997 .- 1573-2576. ; 28:2, s. 77-88
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-8 (IL-8) has been implicated in the pathogenesis of inflammation and cancer. Intracellular levels of cytokine-induced IL-8 in human umbilical vein endothelial cells (HUVEC) were modulated using interferons and steroids to further elucidate their mechanism. Basal and cytokine-induced production of IL-8 was studied using a novel ELISA application, flow cytometry, and RT-PCR. The intracellular amount of IL-8 increased after 6-h stimulation with TNF- (30%) or IL-1ß (55%) which was doubled when Golgi transport was disrupted using monensin. IFN-γ decreased the intracellular amount of IL-8 by 60% in both unstimulated and TNF--stimulated cells, but only when secretion was blocked using monensin. Dexamethasone inhibited the TNF--induced production by 33%, but had no effect in unstimulated cells. Our study indicated that both, dexamethasone and IFN inhibit TNF--induced upregulation of IL-8 at the mRNA level. It could be speculated that they inhibit IL-8 production by affecting different gene regulatory mechanisms.
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| 4. |
- Sjögren, Florence, 1950-, et al.
(författare)
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The influence of retinoic acid and retinoic acid derivatives on Beta2 integrins and L-selectin expression in HL-60 cells in vitro
- 2000
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Ingår i: Inflammation. - 0360-3997 .- 1573-2576. ; 24:1, s. 21-32
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Tidskriftsartikel (refereegranskat)abstract
- A decreased expression of the ▀2-integrin CD11b molecules on peripheral neutrophils from patients with pustular psoriasis occurred during treatment with retinoid compounds. Since this effect could not be mimicked in vitro with isolated peripheral neutrophils, the effect of retinoid compounds on cell differentiation was investigated. The promyelocytic cell line, HL60, was used to study what effect different retinoid compounds had on the cell surface expression of CD11b and L-selectin (CD62L) molecules, complement- mediated phagocytosis, adhesion and the oxidative burst. Retinoid- differentiated cells showed a significantly lower expression of CD11b and CD62L, and a decreased phagocytosis and oxidative burst compared to DMSO- differentiated HL60 cells or peripheral blood neutrophils. The diminished expression of ▀2-integrins or L-selectin did not affect their adhesion to non-activated or lipopolysaccharide-activated endothelial cells in vitro but may however affect adhesion to vascular endothelium under shear forces during blood flow. These results suggest that retinoid treatment could affect several early steps in the inflammatory process.
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| 5. |
- Bjersing, Jan, 1966, et al.
(författare)
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Impact of site-specific nucleobase deletions on the arthritogenicity of DNA
- 2004
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Ingår i: Inflammation. - 0360-3997. ; 28:3, s. 159-68
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Tidskriftsartikel (refereegranskat)abstract
- Oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (CpG ODN) potently stimulate the innate and acquired immune system. We have compared the in vivo and in vitro inflammatogenic properties of CpG ODNs containing a specific nucleobase deletion either 5'-upstream (ODN-2) or 3'-downstream (ODN-3) of the CpG motif, comparing with a prototype CpG ODN (ODN-1). The frequency of arthritis was similar after intra-articular (i.a.) injections of ODN-1 or ODN-3, but was significantly lower (p < 0.02) after i.a. injections of ODN-2. In vitro production of the pro-inflammatory cytokine TNF-alpha was higher in mouse spleen cell cultures exposed to ODN-2 in comparison to ODN-1. In addition, the level of IL-10 induced by ODN-2 was higher than that induced by ODN-1. On the other hand, TNF-alpha, IL-10, and MCP-1 levels, as well as splenocyte proliferative responses were all significantly lower for ODN-3 than for ODN-1. These results suggest that a 5'-upstream nucleobase deletion reduces arthritogenicity, while maintaining or increasing the production of pro- and anti-inflammatory factors. In contrast, a 3'-downstream nucleobase deletion has no effect on arthritogenicity, despite significantly lower levels of proliferation and pro- and anti-inflammatory cytokines, compared with ODN-1. This study indicates that specific structural elements within the ODN sequence but outside the CpG motif, modulate the immunostimulatory properties of CpG ODNs.
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| 6. |
- Bjersing, Jan, 1966, et al.
(författare)
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The arthritogenic and immunostimulatory properties of phosphorothioate oligodeoxynucleotides rely on synergy between the activities of the nuclease-resistant backbone and CpG motifs
- 2004
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Ingår i: Inflammation. - 0360-3997. ; 28:1, s. 39-51
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Tidskriftsartikel (refereegranskat)abstract
- Experiments with immunostimulatory unmethylated CpG-containing DNA are usually conducted with nuclease-protected phosphorothioate oligodeoxynucleotides (S-ODNs), rather than phosphodiester oligodeoxynucleotides (O-ODNs). We compared the murine immune responses to S-ODNs and O-ODNs that either contained or lacked CpG motifs. Both CpG and non-CpG S-ODNs induced synovitis, as did sequence-matched CpG O-ODN, but not GpC O-ODN. There was a minimum length requirement for arthritogenic S-ODNs since a CpC dinucleotide S-ODN did not induce arthritis. There were both sequence- (CpG > non-CpG) and backbone-dependent (S-ODN > O-ODN) differences in the levels of DNA-induced arthritis upon intra-articular injection with the ODNs. However, CpG O-ODN being an exception, induced more severe arthritis than the GpC S-ODN. The levels of in vitro proliferation and production of IL-6, TNF-alpha, IL-12, and RANTES by splenocytes following exposure to CpG S-ODN were significantly higher than those induced by CpG O-ODN. In addition, both proliferative responses and cytokine production induced by S-ODN-stimulated splenocytes increased significantly when the S-ODN contained a CpG motif. Transcription factor NFkappaB was activated by both CpG S-ODN and CpG O-ODN but interestingly not by GpC S-ODN. This indicates that the NFkappaB signal pathway modulates CpG-mediated immunostimulation, while sequence-independent immune activation by the phosphorothioate backbone is probably signalled via a different pathway.
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