Annexin I is stored within gelatinase granules of human neutrophil and mobilized on the cell surface upon adhesion but not phagocytosis

Annexin I, a member of the calcium- and phospholipid-binding annexin superfamily of proteins, is largely present in human neutrophils. To determine its exact intracellular distribution a combination of flow cytometry, confocal microscopy and electron microscopy analyses were performed on resting human neutrophils as well as on cells which had been activated. In resting neutrophils, annexin I was found to be present in small amounts in the nucleus, in the cytoplasm and partially also associated with the plasma membrane. The cytoplasmic pool of annexin I was predominant, and the protein was co-localized with gelatinase (marker of gelatinase granules), but not with human serum albumin or CD35 (markers of secretory vesicles), or with lysosomes. Electron microscopy showed the presence of annexin I inside the gelatinase granules. Neutrophil adhesion to monolayers of endothelial cells, but not phagocytosis of particles of opsonized zymosan, provoked an intense mobilization of annexin I, with a marked externalization on the outer leaflet of the plasma membrane. Remaining intracellular annexin I was also found in proximity of the plasma membrane. These results provide a novel mechanism for annexin I secretion from human neutrophils, which is via a degranulation event involving gelatinase granules.

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)

Reduction of aspirin-induced gastric damage in rats by interleukin-1 beta: possible involvement of endogenous corticosteroids

Administration of interleukin-1 (IL-1; 0.01-3 microgram/kg) by either i.p. or intragastric routes to rats reduced aspirin-induced gastric damage. These effects of IL-1 were not subject to desensitization by its pretreatment and were obtained without modification of the acute anti-inflammatory efficacy of aspirin. Gastroprotection could be effected without major modification of gastric tissue to form prostaglandins I2 or E2. A dose-related decrease of the acidic gastric fluid secretion induced by aspirin was observed with i.p. administered IL-1 was found to reduce gastric fluid volume only at the highest dose tested, although this was not associated with increased gastroprotection. By using adrenalectomized rats the gastric damage induced by aspirin was increased approximately 3-fold. IL-1 treatment, albeit with higher dosage, again reduced lesion formation. Treatment of adrenalectomized rats with dexamethasone and IL-1 synergistically reduced the gastric damage caused by aspirin. In normal rats these treatments caused only an additive reduction of lesion formation although the presence of endogenous glucocorticoid in these animals may mask any effects of the exogenously administered dexamethasone. The glucocorticoid-receptor antagonist, RU 38486, also potentiated aspirin-induced gastric damage and reduced the gastroprotective efficacy of IL-1 without modifying its effect on gastric fluid volume. The data indicate that gastroprotective actions of IL-1 are unlikely to be related upon effects on prostaglandin synthesis or gastric secretion. Endogenous glucocorticoids appear to have a modulatory role in controlling the severity of gastric damage evoked by aspirin and may potentiate the protective actions of IL-1.

Mechanisms underlying the protective effects of interleukin 1 in experimental nonsteroidal anti-inflammatory drug gastropathy

Interleukin 1 (IL-1) has been shown to reduce the severity of experimental gastroduodenal ulceration, but the mechanism of action is unclear. The present study examined the possibility that the mechanism underlying the protective effects of IL-1 in experimental nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy is related to effects on gastric acid secretion, on prostaglandin synthesis, and/or on neutrophil function. IL-1 alpha and IL-1 beta dose-dependently (1-10 micrograms/kg) reduced the severity of gastric damage induced by indomethacin, whereas tumor necrosis factor alpha (1-10 micrograms/kg) had no effect. These effects of IL-1 were not completely attributable to a reduction in the volume or acidity of gastric secretion during the 1-hour pretreatment period. Whereas IL-1 alpha and IL-1 beta significantly inhibited pentagastrin-stimulated acid secretion, the dose-response relationship and time course of actions suggested that effects on acid secretion did not fully account for the ability of these agents to reduce indomethacin-induced gastric injury. The maximally effective dose of IL-1 beta (10 micrograms/kg) in terms of reduction of indomethacin-induced gastric injury did not significantly affect gastric prostaglandin synthesis. Neutrophil function was assessed using two in vivo assays. IL-1 beta inhibited migration of neutrophils in response to intradermal injections of N-formyl-methionyl-leucyl-phenylalanine and leukotriene B4 (LTB4) and dose-dependently (0.1-10 micrograms/kg) inhibited LTB4-induced neutropenia. These effects could be mimicked by dexamethasone (1 mg/kg SC), which inhibited the neutropenic response to LTB4 and significantly (P less than 0.001) reduced the severity of indomethacin-induced gastric damage. Both IL-1 beta and dexamethasone could significantly reduce the extent of histologically detectable leukocyte margination within the gastric mucosal microcirculation after indomethacin administration. The results of this study suggest that effects of IL-1 on gastric acid secretion or prostaglandin synthesis do not fully account for its ability to reduce the severity of experimental NSAID-induced gastropathy, whereas inhibitory effects of IL-1 on neutrophil function may contribute significantly to its protective actions.

Evidence that interleukin-1 and lipoxygenase metabolites mediate the lethal effect of complete Freund's adjuvant in adrenalectomized rats

Injection of complete Freund's adjuvant (CFA) into the right hind paw of adrenalectomized (ADX) rats caused a lethal effect, maximal after 3 days. Treatment of animals with polyclonal sera raised against either murine recombinant (mr) IL-1 alpha or mrIL-1 beta gave significant protection, suggesting the involvement of this cytokine in the observed lethality. Death was also caused by the intravenous injection of human recombinant (hr) IL-1 beta in ADX rats. No lethality was induced by either CFA or hrIL-1 beta in sham-operated (SHO) rats. The administration of dexamethasone or the dural cyclooxygenase/lipoxygenase inhibitor BW 755c significantly protected against the lethality induced by both CFA and hrIL-1 beta. The cyclooxygenase inhibitors, indomethacin and acetylsalicyclic acid, were ineffective. WEB 2086, a PAF-acether receptor antagonist, gave partial but not significant protection. These results suggest that activation of arachidonic acid metabolism is involved in the observed lethality, with lipoxygenase metabolites as possible final effectors. These experimental models of lethalities may be useful for the in vivo evaluation of drugs interfering with the synthesis and/or biological effects of IL-1.

A novel anti-inflammatory peptide from human lipocortin 5

1. A novel anti-inflammatory peptide (residues 204-212) of human recombinant lipocortin 5 (hrLC5) found on the high similarity region with uteroglobin is described. 2. Peptide 204-212 dose-dependently inhibited the contractions of rat isolated stomach strips elicited by porcine pancreatic phospholipase A2 (PLA2). Contractions caused by arachidonic acid (AA), prostaglandin E2 (PGE2) and 5-hydroxytryptamine were not affected. No direct enzyme inhibition was observed in a radiochemical assay. 3. PGE2 release by both human fibroblasts and rat macrophages was reduced by peptide 204-212 in a dose-dependent manner. 4. The development of carrageenin-induced oedema in rats was significantly inhibited by the local administration of peptide 204-212. 5. The pattern and potency of the biological effects of peptide 204-212 are similar to those of antiflammin 2, a lipocortin 1-derived peptide. 6. It is suggested that peptide 204-212 may represent the active site responsible for the anti-inflammatory properties of lipocortin 5.

Alpha-melanocyte-stimulating hormone reduces interleukin-1 beta effects on rat stomach preparations possibly through interference with a type I receptor

Contractions elicited by CaCl2 on isolated rat stomach strip preparations have been reported to be potentiated by interleukin-1 beta (IL-1 beta). We have investigated whether this effect can be reduced by the putative IL-1 beta antagonist, alpha-melanocyte-stimulating hormone (alpha MSH). Additionally, the effects of alpha MSH on the specific binding of IL-1 beta to B- and T-cells have been investigated to further clarify its inhibitory activities. Both alpha MSH and its carboxyl terminal tripeptide concentration dependently reduced the potentiation of CaCl2-induced contractions caused by IL-1 beta but not those caused by leukotriene D4, the parent molecule being approximately 250 times more active. Additionally, both peptides potently and selectively reduced 125I-IL-1 beta binding to the T-cell sub-clone EL4-6.1 but not to the B-cell sub-clone 1H7. The results indicate that IL-1 beta effects on rat stomach may be mediated through a type-I (80 kDa) IL-1 beta receptor.

Persistent effects of interleukin-1 on smooth muscle preparations from adrenalectomized rats: implications for increased phospholipase-A2 activity via stimulation of 5-lipoxygenase

Human recombinant interleukin-1 beta (hrIL-1 beta) potentiated CaCl2-induced contractions of isolated stomach strip preparations from adrenalectomized rats (ADXSS). Associated with this effect were increased prostaglandin E2 and peptidyl leukotriene (LT) synthesis. Unlike preparations from normal rat stomach strips or sham-operated animals, tissue responses and eicosanoid production of ADXSS failed to return to pre-hrIL-1 beta control levels after washout of the interleukin, these effects being abrogated by the lipoxygenase inhibitor nordihydroguaiaretic acid. Additionally, the LTD4 antagonist FPL55712 also prevented the increase in contraction and prostaglandin E2 synthesis caused by hrIL-1 beta without decreasing peptidyl LT synthesis. In separate experiments, hrIL-1 beta failed to increase the recovery of arachidonic acid-induced contractions after aspirin pretreatment in both ADXSS and rat stomach strips. The data indicate that the effects caused by hrIL-1 beta on ADXSS are possibly the result of an exacerbated phospholipase A2 activity particularly inasmuch as increases in cellular cyclooxygenase synthesis are unlikely in this experimental system. It appears likely that a peptidyl LT is involved in this process. Elevation of phospholipase A2 activity by interleukin-1 like drugs may be an important factor limiting the use of these agents as adjuvants particularly in patients with low blood glucocorticoid levels.

Reduction of the severity of experimental gastric and duodenal ulceration by interleukin-1 beta

Interleukin-1 beta (IL-1 beta) has been reported to stimulate prostaglandin synthesis by the rat stomach in vitro and to inhibit gastric acid secretion in vivo. We have therefore tested the hypothesis that IL-1 beta might have protective actions in experimental models of gastroduodenal ulceration. IL-1 beta, given i.p., dose and time dependently reduced the severity of ethanol-induced gastric damage. A pretreatment time of 90 min was found to produce the greatest reduction of damage, while doses of 0.1 micrograms/kg or greater were found to produce significant effects. The protective actions of IL-1 beta were abolished by prior boiling or by pretreatment of the animals with indomethacin, and were not shared by the nonapeptide fragment 163-171. IL-1 beta also reduced the severity of gastric damage induced by indomethacin and the duodenal ulceration induced by cysteamine. The results indicate that IL-1 beta has protective actions in three separate experimental models of gastroduodenal ulceration. The mechanism of action of IL-1 beta is not entirely clear, but contributions of endogenous prostaglandin synthesis and inhibition of gastric acid secretion cannot be excluded.

Arachidonic acid lipoxygenation may be involved in interleukin-1 induction of prostaglandin biosynthesis

The induction of prostaglandin (PG) biosynthesis by human recombinant interleukin-1 beta (hrIL-1 beta) has been investigated using rat-isolated stomach strip preparations. hrIL-1 beta (30 and 120 pM) increased CaCl2 responses in a dose-dependent manner with both concentrations significantly potentiating maximum contraction (62.4 +/- 5.1 and 184.2 +/- 36.9%, respectively). This enhancement was characterized further using inhibitors of arachidonic acid metabolism, mRNA and protein synthesis as well as a selective leukotriene (LT) D4 antagonist. Indomethacin (5.6 microM) reduced CaCl2 contractions in the presence of hrIL-1 beta (30 pM) such that only a small residual response was evident, this being reduced further by NDGA (20 microM). Contrastingly, nordihydljroguaiaretic acid reduced only the enhancement of response due to hrIL-1 beta. These findings, supported by parallel radio-immunoassay of PGE2 in the bathing medium after drug treatments suggest strongly that the augmentation of contraction by hrIL-1 beta is due mainly to increased production of PGs. Furthermore, this enhancement is inhibited in a dose-dependent manner by the LTD4 antagonist FPL55712. Additionally, using actinomycin-D and cycloheximide we demonstrated that the hrIL-1 beta induced potentiation is dependent upon mRNA and protein biosynthesis as both compounds substantially reduced responses in the presence of the interleukin. These results provide possible evidence that hrIL-1 beta induced PG production is mediated by a lipoxygenase product, most likely LTD4, which in turn could be important for the induction of de novo protein synthesis.

Prostacyclin modulates the responses to leukotrienes C4 and D4 of guinea-pig airway smooth muscle

Superfusion of lung parenchymal strips or tracheal strips from the guinea-pig with effluent from perfused isolated lungs reduced the contractions elicited by leukotriene C4 (LTC4) and leukotriene D4 (LTD4) but not those elicited by acetylcholine (ACh). Incubation of the lung perfusate for 15 min at 37 degrees C removed the inhibitory effect, as did treatment of the lungs with indomethacin (0.5 microgram ml-1) suggesting that a labile cyclo-oxygenase product was causing the inhibition. Addition of prostacyclin (0.8-5.0 ng ml-1) to the fluid superfusing tracheal and parenchymal strips produced a dose-related decrease in leukotriene-induced contractions, whereas 6-oxo-PGF1 alpha and PGE2 were inactive. Contractions of tracheal strips induced by LTC4 were significantly enhanced by infusion of PGF2 alpha. Parenchymal strips usually developed tachyphylaxis to repeated doses of LTC4. This tachyphylaxis has less evident in the presence of indomethacin (2 micrograms ml-1). Contractions of parenchymal and tracheal strips to histamine, acetylcholine and the stable thromboxane mimetic U-46619 were unaffected by infusion of prostacyclin (5 ng ml-1). These results indicate that prostacyclin selectively antagonises airway smooth muscle reactivity to LTC4 and LTD4 by a mechanism which remains to be elucidated.

Inhibition of tissue damage by the arachidonate lipoxygenase inhibitor BW755C

The effects of three anti-inflammatory drugs, which interfere with arachidonic acid transformation by three different enzymes, have been compared by using a simple model of tissue damage and foreign body rejection. In groups of control rats, subcutaneously implanted polyester sponges were rejected after a mean of 12 days. Indomethacin, which selectively inhibits prostaglandin synthesis, did not significantly change time to rejection but BW755C (3-amino-1-[m-(trifluoromethyl) phenyl]-2-pyrazoline), which is a dual inhibitor of prostaglandin and leukotriene synthesis, prolonged time to rejection to a mean of 22 days. The anti-inflammatory steroid dexamethasone, which reduces arachidonic acid metabolism by stimulating the formation of a phospholipase inhibitor, prolonged time to sponge rejection as BW755C did. Treatment with BW755C or dexamethasone was also accompanied by a reduction in total leukocyte numbers in inflammatory exudates collected at 1-14 days, whereas indomethacin increased leukocyte migration on days 1 and 2 and had no effect at later times. These results suggest that the inhibition of the leukotriene-forming lipoxygenase suppresses leukocyte activation and that this leads to a reduced rate of tissue damage in experimental inflammation.

The effects of non-steroid anti-inflammatory drugs on leukocyte migration in carrageenin-induced inflammation

Some non-steroid anti-inflammatory drugs which inhibit arachidonate cyclo-oxygenease have been examined for their effects on leukocyte migration, prostaglandin production and oedema formation in carrageenin-induced inflammation in the rat. At doses which inhibited oedema, all the drugs tested caused a dose-dependent reduction in numbers of leukocytes and prostaglandin concentrations in 24-h inflammatory exudates. At lower doses, indomethacin, aspirin, sodium salicylate, flurbiprofen and phenylbutazone significantly potentiated leukocyte migration by 20-70%. Ibuprofen, naproxen and BW755C reversed the indomethacin-induced increase in leukocyte accumulation. BW755C inhibits the generation of chemotactic lipoxygenase products and it is possible that the effects of all these drugs on leukocyte migration are mediated through the lipoxygenase pathway of arachidonic acid metabolism.

Use of the rabbit transverse stomach-strip to identify and assay prostacyclin, PGA2, PGD2 and other prostaglandins

The preparation and use of the rabbit transverse stomachstrip as an isolated assay tissue for prostaglandins is described. The tissue is relaxed by low concentrations of PGE2, PGA2 and PGD2 and contracted by prostacyclin (PGI2) and PGF2alpha. The decomposition product of prostacyclin, 6-oxo-PGF1alpha, has little effect, whereas the endoperoxide PGH2 and thromboxane A2 cause a small contraction. Arachidonic acid also contracts the tissue and this response is abolished by indomethacin. This tissue also responds to low concentrations of histamine, acetylcholine, noradrenaline and bradykinin. In conjunction with other bioassay tissues such as the rat stomach strip and rabbit coeliac artery, the rabbit transverse stomach strip provides a convenient method of detection of identification of known arachidonic acid metabolites.