Biomedical subjects

M Perretti

Publications and source records attributed to M Perretti.

At least 91 records · Page 5Linked to original sources

PubMed1997

Molecular determinants of monosodium urate crystal-induced murine peritonitis: a role for endogenous mast cells and a distinct requirement for endothelial-derived selectins.

Injection of monosodium urate (MSU) crystals, the etiological cause of gouty arthritis, into murine peritoneal cavities produced an intense recruitment of polymorphonuclear leukocytes (PMN). After 3 mg MSU crystal injection, cell influx was maximal (approximately 10 x 10[6] cells per mouse) at 6 hr postinjection and sustained up to the 24 hr time-point. In mice depleted of mast cells by administration of compound 48/80 72 hr before challenge with MSU crystals a lower PMN influx was measured (58% reduction). The occurrence of endogenous mast cell activation, in the MSU response, was validated by the observation that MSU challenge reduced by more than 90% the number of intact mast cells recovered in the peritoneal washes. Pretreatment of mice with a histamine H1 antagonist (tripolidine; 0.5 mg/kg) or a platelet-activating factor receptor antagonist (WEB2086; 10 mg/kg) significantly reduced by 50 to 60% the number of PMN recovered from the peritoneal cavities. The molecular determinants of this process of leukocyte recruitment were also investigated. Treatment of mice with an anti-CD62P or anti-CD62E monoclonal antibody (mAb; 100 microg i.v.) produced a distinct inhibition of PMN recruitment measured at 6 hr, whereas only a combined administration of both monoclonal antibodies was effective in reducing by 60% the influx of PMN caused by the MSU crystals within 24 hr. In conclusion, these data highlight a role for endogenous mast cells and for endothelial-derived selectins in MSU crystal-induced PMN recruitment into the peritoneal cavity, and may be useful to dissect molecular mechanism(s) which may be operating in gouty arthritis.

Animals↗

PubMed1996

Modulation of ICAM-1 levels on U-937 cells and mouse macrophages by interleukin-1 beta and dexamethasone.

Differentiation of U-937 cells with phorbol ester (10 nM) induced a time-dependent (24 h or 48 h) increase of adhesion molecules and lipocortin 1 expression on the cell surface. Stimulation with interleukin-1 beta for a further 16 h increased the levels of intercellular adhesion molecule-1, and this effect was inhibited by co-incubation with 0.1-1 microM dexamethasone. The effect of the glucocorticoid was not modified by addition of a specific anti-lipocortin 1 monoclonal antibody (mAb 1A, 5 micrograms/ml). This opposite modulatory role of interleukin-1 and dexamethasone on intercellular adhesion molecule-1 expression was also, for the first time, observed in vivo using mouse peritoneal macrophages: a four-fold increase in intercellular adhesion molecule-1 expression was measured after local administration of the cytokine (5 micrograms/kg) and this effect was greatly inhibited (> 70%) by co-injection with 1 microgram dexamethasone. In conclusion, modulation of intercellular adhesion molecule-1 expression by glucocorticoids is an effect independent endogenous lipocortin 1, and it is an in vivo feature of these potent anti-inflammatory drugs.

Animals↗

PubMed1996

Relative contribution of the selectins in the neutrophil recruitment caused by the chemokine cytokine-induced neutrophil chemoattractant (CINC).

Rat CINC induced a dose- and time-dependent accumulation of neurophils into murine air-pouches, a response which was inhibited by two selective H1-antagonists, mepyramine and triprolidine (approximately 60%). As pretreatment with fucoidin abolished CINC effect, the relative time-related contribution of selectins on this process was then investigated by using specific monoclonal antibodies (mAb). Anti-CD62L mAb gave a similar degree of inhibition of CINC-induced cell accumulation both at the 2h and 4h time-point (approximately 75%). Anti-CD62P mAb, but not the anti-CD62E mAb, inhibited PMN accumulation at 2h (65%), but only co-administration of these two mAbs inhibited the cell response to CINC at the 4h time-point (90%). Thus endogenous histamine, CD62L, CD62P, and CD62E, though to a different degree, are required for PMN extravasation observed in response to CINC administration.

Animals↗

PubMed1996

Effect of interleukin-1 beta on the release of substance P from rat isolated spinal cord.

Superfusion of rat spinal cord slices with rat interleukin-1 beta resulted in a significant enhancement of electrically evoked substance P-like immunoreactivity with a maximal effect (> 2-fold increase) at 0.1 ng/ml, whereas higher concentration (10-50 ng/ml) of the cytokine inhibited (approximately 50%) the release of the neuropeptide. Interleukin-1 beta (0.1 ng/ml) potentiation of substance P-like immunoreactivity release was abrogated by co-perfusion with interleukin-1 receptor antagonist (10-100 ng/ml) or with indomethacin (1 microM). Superfusion of spinal cord with interleukin-1 beta inhibited electrically evoked calcitonin gene-related peptide-like immunoreactivity release. Modulation of substance P-like immunoreactivity release from the spinal cord by interleukin-1 beta may represent a mechanism responsible for the hyperalgesic action of the cytokine characteristic of the inflammatory response.

Animals↗

PubMed1996

Involvement of bradykinin B1 receptors in the polymorphonuclear leukocyte accumulation induced by IL-1 beta in vivo in the mouse.

Local application of the bradykinin B1 receptor antagonist desArg9[Leu8]BK, but not the B2 receptor antagonist Hoe 140, attenuated by approximately 50% the polymorphonuclear leukocyte accumulation into 6-day-old air pouches observed in response to application of murine IL-1 beta (5 ng). The selective appearance of a chemotactic response to the bradykinin B1 receptor agonist desArg9BK only in air pouches pretreated (4 h) with IL-1 beta indicated the involvement of this receptor type during this acute inflammation model. The pro-migratory action of desArg9BK was magnified when the effect of IL-1 on polymorphonuclear leukocyte accumulation had subsided (i.e., 24 h post-IL-1). desArg9[Leu8]BK, but not Hoe 140, antagonized the effect of desArg9BK, indicating an action on B1 receptors, but not B2 receptors. The cellular infiltration observed following application of desArg9BK in IL-1-sensitized air pouches was due to the release of neuropeptides from C fibers, as indicated by the inhibitory action of the substance P antagonist, RP 67,580, and the calcitonin-gene related peptide antagonist, CGRP-(8-37). In conclusion, this study provides evidence that activation of C fibers, which is necessary for the achievement of a full chemotactic action of IL-1, is due to up-regulation (or induction) of bradykinin B1 receptors and describes, for the first time, a relationship between these receptors and polymorphonuclear leukocyte recruitment.

Animals↗

PubMed1996

Mobilizing lipocortin 1 in adherent human leukocytes downregulates their transmigration.

Polymorphonuclear leukocyte (PMN) migration into sites of inflammation is fundamental to the host defense response. Activation of endothelial cells and PMNs increases the expression or activation of adhesion molecules, culminating in rolling and subsequent adherence of these cells to the vascular wall. Further activation of adherent PMNs, possibly by endothelial cell ligands, leads, within a few minutes, to extravasation itself. This process is not clearly understood, but adhesion molecules or related proteins, as well as endogenous chemokines, may play an important role. The anti-inflammatory glucocorticoids delay extravasation, which implies that an inhibitory regulatory system exists. Resting PMNs contain abundant cytoplasmic lipocortin 1 (LC1, also called annexin I)', and the activity profile of this protein suggests that it could reduce PMN responsiveness. To investigate this we have assessed neutrophil transmigration both in vivo and in vitro and examined the content and subcellular distribution of LC1 in PMNs by fluorescence-activated cell-sorting (FACS) analysis, western blotting and confocal microscopy. We report that LC1 is mobilized and externalized following PMN adhesion to endothelial monolayers in vitro or to venular endothelium in vivo and that the end point of this process is a negative regulation of PMN transendothelial passage.

Animals↗

PubMed1996

Measurement of lipocortin 1 levels in murine peripheral blood leukocytes by flow cytometry: modulation by glucocorticoids and inflammation.

1. Lipocortin 1 (LC1) immunoreactivity in murine peripheral blood leukocytes was quantified by use of a flow cytometric technique associated with a permeabilisation protocol with saponin. Using specific antisera raised against the whole protein or against its N-terminus peptide, cell-associated LC1-like immunoreactivity was easily detected in circulating neutrophils and monocytes, whereas very low levels were found in lymphocytes. Of the total protein measured 17.6% and 36% were associated with the external plasma membrane in neutrophils and monocytes, as assessed in the absence of cell permeabilisation, whereas no signal was detected on lymphocyte plasma membrane. 2. Treatment of mice with dexamethasone (Dex; 0.5-5 micrograms per mouse corresponding to approximately 0.015-1.5 mg kg-1) increased LC1 levels in neutrophils and monocytes. The 2-3 fold increase in LC1 levels was time-dependent with a peak at 2 h. Treatment of mice with the steroid antagonist, RU486 (two doses of 20 mg kg-1 orally) decreased LC1-like immunoreactivity in all three types of circulating leukocytes by > or = 50%. 3. Extravasation of blood neutrophils into inflamed tissue sites resulted in a consistent reduction (> or = 50%) in LC1 levels compared with circulating neutrophils. A high LC1-like immunoreactivity was also measured in resident macrophages, of which approximately one third was membrane-associated. Induction of an acute inflammatory response in the murine peritoneal cavity did not modify total LC1 levels measured in macrophages, but reduced membrane-associated LC1 to a significant extent, i.e. up to 70%. 4. In conclusion, flow cytometric analysis is a rapid and convenient method for detecting and measuring LC1 in murine leukocytes. We confirmed that LC1 protein expression is controlled by exogenous and endogenous glucocorticoids. Amongst other factor(s) influencing protein concentrations, extravasation was found to be associated with a reduced LC1 expression in the emigrated cells.

Animals↗

PubMed1996

Acute inflammatory response in the mouse: exacerbation by immunoneutralization of lipocortin 1.

1. An immuno-neutralization strategy was employed to investigate the role of endogenous lipocortin 1 (LC1) in acute inflammation in the mouse. 2. Mice were treated subcutaneously with phosphate-buffered solution (PBS), non-immune sheep serum (NSS) or with one of two sheep antisera raised against LC1 (LCS3), or its N-terminal peptide (LCPS1), three times over a period of seven days. Twenty four hours after the last injection several parameters of acute inflammation were measured including zymosan-induced inflammation in 6-day-old air-pouches, zymosan-activated serum (ZAS)-induced oedema in the skin, platelet-activating factor (PAF)-induced neutrophilia and interleukin-1 beta (IL-1 beta)-induced corticosterone (CCS) release. 3. At the 4 h time-point of the zymosan inflamed air-pouch model, treatment with LCS3 did not modify the number of polymorphonuclear leucocytes (PMN) recruited: 7.84 +/- 1.01 and 7.00 +/- 0.77 x 10(6) PMN per mouse for NSS- and LCS3 group, n = 7. However, several other parameters of cell activation including myeloperoxidase (MPO) and elastase activities were increased (2.2 fold, P < 0.05, and 6.5 fold, P < 0.05, respectively) in the lavage fluids of these mice. Similarly, a significant increase in the amount of immunoreactive prostaglandin E2 (PGE2; 1.81 fold, P < 0.05) and IL-1 alpha (2.75 fold, P < 0.05), but not tumour necrosis factor-alpha (TNF-alpha), was also observed in LCS3-treated mice. 4. The recruitment of PMN into the zymosan inflamed air-pouches by 24 h had declined substantially (4.13 +/- 0.61 x 10(6) PMN per mouse, n = 12) in the NSS-treated mice, whereas high values were still measured in those treated with LCS3 (9.35 +/- 1.20 x 10(6) PMN per mouse, n = 12, P < 0.05). A similar effect was also found following sub-chronic treatment of mice with LCPS1: 6.48 +/- 0.10 x 10(6) PMN per mouse, vs. 2.77 +/- 1.20 and 2.64 +/- 0.49 x 10(6) PMN per mouse for PBS- and NSS-treated groups (n = 7, P < 0.05). Most markers of inflammation were also increased in the lavage fluids of LCS3-treated mice: MPO and elastase showed a 2.47 fold and 17 fold increase, respectively (P < 0.05 in both cases); TNF-alpha showed a 11.1 fold increase (P < 0.05) whereas the IL-1 alpha levels were not significantly modified. PGE2 was still detectable in most (5 out of 7) of the mice treated with LCS3 but only in 2 out of 7 of the NSS-treated mice. 5. Intradermal injection of 50% ZAS caused a significant increase in the 2 hoedema formation in the skin of LCS3-treated mice in comparison to PBS- and NSS-treated animals: 16.7 +/- 1.5 microliters vs. 10.8 +/- 1.2 microliters and 10.2 +/- 1.0 microliters, respectively (n = 14 mice per group, P < 0.05). ZAS-induced oedema had subsided by 24 h in control animals but a residual significant amount of extravasation was still detectable in LCS3-treated mice: 4.4 +/- 0.8 microliters (P < 0.05). 6. A recently described model driven by endogenous glucocorticoids is the blood neutrophilia observed following administration of PAF. In our experimental conditions, a single bolus of PAF (100 ng, i.v.) provoked a marked neutrophilia at 2 h (2.43 and 2.01 fold) in NSS- and PBS-treated mice (n = 11), respectively, which was significantly attenuated in the animals treated with LCS3: 1.26 fold increase in circulating PMN (n = 11, P < 0.01 vs. NSS- and PBS-groups). 7. Intraperitoneal injection of IL-1 beta (5 micrograms kg-1) caused a marked increase in circulating plasma CCS by 2 h, to a similar extent in all experimental groups. In contrast, measurement of CCS levels in the plasma of mice bearing air-pouches inflamed with zymosan revealed significant differences between LCS3 and NSS-treated mice at the 4 h time-point: 198 +/- 26 ng ml-1 vs. 110 +/- 31 ng ml-1 (n = 8, P < 0.05). 8. In conclusion, we found a remarkable exacerbation of the inflammatory process with respect to both humoral and cellular components in mice passively immunised agains

Animals↗

PubMed1995

Selective inhibition of neutrophil function by a peptide derived from lipocortin 1 N-terminus.

A multi-faceted approach was used to investigate the effect of an anti-inflammatory peptide derived from human lipocortin 1 N-terminus region (amino acid 2-26; termed human Ac2-26) on human neutrophil activation in vitro. When incubated with purified human neutrophils. human Ac2-26 produced a concentration-dependent inhibition of elastase release stimulated by formyl-Met-Leu-Phe (fMLP), platelet-activating factor, or leukotriene B4, with an approximate EC50 of 33 microM (100 micrograms/ml). At this concentration, human Ac2-26 also inhibited (77%) the release of [3H]-arachidonic acid from neutrophils stimulated with fMLP. The peptide, however, did not inhibit the up-regulation of the beta 2-integrin CD11b and the concomitant shedding of L-selectin from neutrophil plasma membrane induced by fMLP. In adhesion experiments, human Ac2-26 inhibited neutrophil adhesion to endothelial monolayers when this was stimulated with fMLP, but not when this followed endothelial cell activation with histamine or platelet-activating factor. Again, the effect of the peptide was concentration-dependent, and an approximate EC50 of 33 microM was calculated. When a preparation of 125I-labeled human Ac2-26 was incubated with the neutrophils, the peptide was internalised in an energy-dependent fashion. All together, these observations lead us to propose a model in which this peptide derived from the N-terminus of human lipocortin 1 alters a common cellular mechanism producing a selective inhibition of neutrophil activation.

Amino Acid Sequence↗

PubMed1995

Endogenous corticosteroids mediate the neutrophilia caused by platelet-activating factor in the mouse.

Platelet-activating factor (PAF; 100 ng i.v.) transiently modified the number of circulating neutrophils in the mouse, inducing a fast neutropenia (2 min) followed by a late onset neutrophilia (2 h). The potential involvement in PAF-induced neutrophilia of granulocytotic agents such as interleukin-1 and tumor necrosis factor-alpha could be excluded on the basis of the ineffectiveness of interleukin-1 receptor antagonist and of a specific monoclonal antibody anti-murine tumor necrosis factor-alpha. PAF granulocytosis was preceded by a significant rise in plasma corticosterone at 20 min. The involvement of endogenous corticosteroids was confirmed by the experiments with adrenalectomized mice and in animals pretreated with the steroid antagonist RU486 (11 beta-(4-dimethyl amino-phenyl) 17 beta-hydroxy, 17 alpha(prop-1-ynyl) estra 4,9-dien-3-one), where PAF-induced neutrophilia was greatly reduced (approximately 50%). Moreover, sustained increase in plasma corticosterone by administration of adrenocorticotropic hormone was paralleled by an intense neutrophilia. We show evidence that endogenous corticosterone acts through the glucocorticoid-inducible protein lipocortin 1.

Adrenal Cortex Hormones↗

PubMed1995

Effect of rolipram in a murine model of acute inflammation: comparison with the corticoid dexamethasone.

Treatment of mice with rolipram, a phosphodiesterase type 4 inhibitor, selectively modified the acute inflammatory reaction elicited by zymosan administration in 6-day-old mouse air-pouches. Rolipram (1-10 mg kg-1, i.p.) prevented the rise of endogenous tumor necrosis factor-alpha (TNF-alpha) in the lavage fluids (approximately 60% inhibition) induced by zymosan, with no effect upon interleukin-1 alpha levels. This action was not accompanied by changes in neutrophil accumulation, but the amount of elastase released in the lavage fluids was significantly reduced (approximately 50%). Dexamethasone (1.5 mg kg-1, i.v.), used for comparative purposes, significantly reduced the release of TNF-alpha (> 50%), interleukin-1 alpha (> 70%) and cellular infiltration (approximately 50%), but had only a marginal effect on the release of elastase activity. In conclusion, in this murine model of acute inflammation induced by zymosan, rolipram inhibited the endogenous TNF-alpha production at a local site of inflammation, such as the subcutaneous air-pouch, and prevented the full activation of migrated cells.

Acute Disease↗

PubMed1995

Inhibition of interleukin-1 beta-induced pyresis in the rabbit by peptide 204-212 of lipocortin 5.

The intracerebroventricular administration of interleukin-1 beta (12.5 ng/kg) in rabbits caused a prompt rise of prostaglandin E2 concentration (+ 632.6 +/- 243.9%) in the cerebrospinal fluid followed by hyperthermia (+ 1.61 +/- 0.14 delta degrees C). The intracerebroventricular administration of an anti-inflammatory nonapeptide (amino acids 204-212, SHLRKVFDK) derived from lipocortin 5, thereafter referred to as lipocortin 5-(204-212)-peptide, inhibited in a significant manner both the increase in cerebrospinal fluid [prostaglandin E2] and the febrile response induced by the cytokine. This inhibitory effect is probably due to interference by the peptide with phospholipase A2 activity. A control peptide (FKRVHDLKS) formed by the same amino acids in a randomly shuffled sequence had no effect. These results show that, in addition to the anti-inflammatory effect previously reported, the peptide 204-212 of lipocortin 5 possesses, like glucocorticoids, anti-pyretic activity. The research on lipocortin-derived peptides may lead to the development of novel anti-inflammatory and anti-pyretic compounds.

Amino Acid Sequence↗

PubMed1995

Leukocyte transmigration, but not rolling or adhesion, is selectively inhibited by dexamethasone in the hamster post-capillary venule. Involvement of endogenous lipocortin 1.

This study investigates the effect of dexamethasone on leukocyte extravasation in the post-capillary venules of the hamster cheek pouch, using an intravital microscopy technique, and seeks to clarify the potential involvement of the steroid-inducible protein lipocortin 1. Topical application of FMLP (10 nmol), or substance P (10 nmol), to the superfused cheek pouch induced at the level of the post-capillary venules the three characteristic phenomena of leukocyte rolling, adhesion, and transmigration. Pretreatment of hamsters with an anti-inflammatory dose of dexamethasone (1 mg/kg) increased lipocortin 1 levels in circulating leukocytes as assessed by flow cytometry, but did not modify either leukocyte rolling or the number of adherent cells; however approximately 65% of the adherent leukocytes subsequently detached and returned to the blood stream, whereas those that entered into the diapedesis process exhibited a long latency (approximately three- to fourfold longer than in control animals) before transmigration. In hamsters passively immunized with a polyclonal anti-lipocortin 1 serum, leukocyte diapedesis started at similar times in both control and dexamethasone-treated animals, whereas a significant prolongation was observed in those animals treated with a non-immune sheep serum. These observations indicate that 1) lipocortin 1 is elevated in circulating leukocytes following dexamethasone treatment; 2) the step of leukocyte extravasation affected by dexamethasone in the actual transmigration process, and 3) this specific effect upon leukocyte diapedesis is mediated by endogenous lipocortin 1.

Amino Acid Sequence↗

PubMed1995

Alteration of neutrophil trafficking by a lipocortin 1 N-terminus peptide.

Sialidase, fucoidin and a peptide corresponding to most of lipocortin 1 N-terminus, termed LC1-(Ac2-26)-peptide, induced an intense 2 h neutrophilia whereas a monoclonal antibody to murine CD11b induced an effect by 1 h. The neutropenic response stimulated by platelet-activating factor (PAF) was significantly reduced in the presence of sialidase, fucoidin, LC1-(Ac2-26)-peptide and monoclonal antibody anti-CD11b. Neutrophil migration into a 6-day-old mouse air-pouch induced by interleukin-1 was inhibited by all the pharmacological agents. In vitro, PAF up-regulated CD11b expression on the neutrophil surface but neither human or mouse LC1-(Ac2-26)-peptide inhibited this response. CD11b up-regulation on neutrophils occurred after PAF administration in vivo and was maximal at 2 min. LC1-(Ac2-26)-peptide mimics the action of agents interfering with leucocyte rolling and adhesion in vivo, however, does not inhibit CD11b up-regulation in vitro suggesting other phenomena are important in the activity of this peptide.

Amino Acid Sequence↗

PubMed1995

Lipocortin 1 mediates the inhibition by dexamethasone of the induction by endotoxin of nitric oxide synthase in the rat.

Administration of Escherichia coli lipopolysaccharide (LPS; 10 mg/kg i.v.) to male Wistar rats caused within 240 min (i) a sustained fall (approximately 30 mmHg) in mean arterial blood pressure, (ii) a reduction (> 75%) in the pressor responses to norepinephrine (1 microgram/kg i.v.), and (iii) an induction of nitric oxide synthase (iNOS) as measured in the lung. Dexamethasone (1 mg/kg i.p. at 2 h prior to LPS) attenuated the hypotension and the vascular hyporeactivity to norepinephrine and reduced (by approximately 77%) the expression of iNOS in the lung. These effects of dexamethasone were prevented by pretreatment of LPS-treated rats with a neutralizing antiserum to lipocortin 1 (anti-LC1; 60 mg/kg s.c. at 24 h prior to LPS) but not by a control nonimmune sheep serum. Stimulation of J774.2 macrophages with LPS (1 microgram/ml for 24 h) caused the expression of iNOS and cyclooxygenase 2 (COX-2) protein and significantly increased nitrite generation; this was prevented by dexamethasone (0.1 microM at 1 h prior to LPS), which also increased cell surface lipocortin 1. Pretreatment of J774.2 cells with anti-LC1 (1:60 dilution at 4 h prior to LPS) also abolished the inhibitory effect of dexamethasone on iNOS expression and nitrite accumulation but not that on COX-2 expression. A lipocortin 1 fragment (residues 1-188 of human lipocortin 1; 20 micrograms/ml at 1 h prior to LPS) also blocked iNOS in J774.2 macrophages activated by LPS (approximately 78% inhibition), and this too was prevented by anti-LC1. We conclude that the extracellular release of endogenous lipocortin 1 (i) mediates the inhibition by dexamethasone of the expression of iNOS, but not of COX-2, and (ii) contributes substantially to the beneficial actions of dexamethasone in rats with endotoxic shock.

Amino Acid Oxidoreductases↗

PubMed1995

Anti-inflammatory lipocortin-derived peptides.

Peptide Ac2-26, drawn from the sequence of human lipocortin 1, inhibited the release of elastase activity from cytoplasmic granules of human neutrophils, and neutrophil adhesion to monolayers of endothelial cells, in a concentration-dependent manner (approximate IC50 of 100 micrograms/ml, 33 microM). The effect of peptide Ac2-26 was not restricted to a specific neutrophil activator, being effective against formyl-Met-Leu-Phe (FMLP), leukotriene B4 (LTB4) and platelet-activating factor (PAF). Peptide Ac2-26 did not alter FMLP binding to its receptor. These in vitro observations complement in vivo data obtained with this peptide and may enable a better understanding of its pharmacology and, perhaps, that of of lipocortin 1 too.

Amino Acid Sequence↗

PubMed1995

Effect of interleukin-4 and interleukin-10 on leucocyte migration and nitric oxide production in the mouse.

1. The effect of systemic treatment of mice with murine recombinant interleukin-4 (IL-4) or interleukin-10 (IL-10) on neutrophil infiltration into a specific tissue site and nitric oxide (NO) production from peritoneal macrophages was investigated. 2. Intravenously (i.v.) administered IL-4 (0.01-10 micrograms per mouse, approximately 0.3-300 micrograms kg-1, i.v.) and IL-10 (0.01-1 micrograms per mouse, approximately 0.3-30 micrograms kg-1, i.v.) dose-dependently inhibited neutrophil accumulation into a 6-day-old murine air-pouch induced by local application of interleukin-1 beta (IL-1 beta, 5 ng), with approximate ED50s of 0.35 and 0.90 micrograms, respectively. Neither IL-4 (1 micrograms, 30 micrograms kg-1, i.v.) nor IL-10 (1 micrograms, 30 micrograms kg-1, i.v.) prevented leucocyte accumulation in the mouse air-pouches when interleukin-8 (IL-8, 1 micrograms) was used as chemoattractant. Similarly, neither cytokine had any effect on the in vitro up-regulation of CD11b antigen on the surface of murine circulating neutrophils. 3. Treatment of mice with lipopolysaccharide (LPS, 0.3 mg kg-1, i.p.) caused an increase in the formation of NO (measured as nitrite accumulation) in the supernatant of peritoneal macrophages ex vivo. Pretreatment of mice with IL-4 (0.01-1 micrograms i.v., 20 min before LPS), but not with IL-10 (1 micrograms i.v., 20 min before LPS), caused a dose-dependent reduction in this LPS-stimulated formation of nitrite by peritoneal macrophages ex vivo. 4. Activation of murine macrophages with LPS (1 microgram ml-1 for 24 h) in vitro caused a significant increase in nitrite release in the supernatant of these cells. Pretreatment of either J774.2 or peritoneal macrophages with IL-4 (0.1-1 microg ml-1, 20 min before LPS), but not with IL-1O (1 microg ml', 20 min before LPS) caused a concentration-related attenuation of this LPS-stimulated nitrite formation.5 Thus, both IL-4 and IL-10 inhibit the migration of leucocytes (stimulated by IL-1beta>) in vivo; IL-4 (but not IL-10) inhibits the induction of NO synthase caused by LPS in murine macrophages in vitro and ex vivo.

Animals↗

PubMed1995

Gastric antisecretory and anti-ulcer actions of IL-1 in rat involve different IL-1 receptor types.

Limited knowledge exists concerning the interleukin-1 (IL-1) receptor type (IL-1RT) mediating the potent antisecretory and gastro-protective actions of IL-1. In the present study, the gastric actions of IL-1 beta and two related mutant proteins, yIL-1 beta delta 4, an analogue that preferentially binds to IL-1-RTII, and mutant yIL-1 beta N7/Q, an analogue that has equal affinity as IL-1 beta for IL-1RTI and IL-1RTII, have been compared. Modulation of IL-1 gastric actions were also investigated using monoclonal antibody (MAb) preparations raised against IL-1RTI or IL-1RTII. In the pylorus-ligated rat, yIL-1 beta delta 4, yIL-1 beta N7/Q, and IL-1 beta (all at 1 microgram/kg ip) reduced gastric acid secretion (50, 79, and 78%, respectively), indicating the importance of IL-1RTII binding for antisecretory activity. This was further substantiated in experiments using the MAb preparations, which showed that IL-1 beta (1 microgram/kg ip) antisecretory activity was reversed by MAb IL-1RTII (10-50 micrograms/kg sc) but not by MAb IL-1RTI (50 micrograms/kg sc). In contrast, at dosages 10-fold higher (10 micrograms/kg ip) than that used in the study to inhibit acid secretion, IL-1 beta and yIL-1N7/Q equally reduced (approximately 80%) indomethacin-induced gastric damage, but yIL-1 beta delta 4 was ineffective. The results using yIL-1 beta delta 4 indicated that impairment of IL-1RTI binding capacity appeared to be paralleled by a decreased gastroprotective effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗