Interleukin-1 type II receptor: a decoy target for IL-1 that is regulated by IL-4

Interleukin-1 (IL-1) interacts with cells through two types of binding molecules, IL-1 type I receptor (IL-1R I) and IL-1R II. The function of IL-1R II is unknown. In studies using monoclonal antibodies, IL-1 prolonged the in vitro survival of polymorphonuclear cells (PMN) through IL-1R I, and IL-4 antagonized the action of IL-1 by inducing expression and release of IL-1R II. Dexamethasone also induced expression and release of the IL-1R II in PMN. These results, together with the effect of antibodies to IL-1R on IL-1-induced production of cytokines in monocytes, indicate that IL-1 acts on myelomonocytic cells through IL-1R I and that IL-1R II inhibits IL-1 activity by acting as a decoy target for IL-1. The existence of multiple pathways of regulation emphasizes the need for tight control of IL-1 action.

Pharmacological activities of chlorpromazine involved in the inhibition of tumour necrosis factor production in vivo in mice

Chlorpromazine (CPZ) was shown to inhibit tumour necrosis factor (TNF) production in vivo. Several drugs sharing one of the various pharmacological activities of CPZ were tested in endotoxin-treated mice. It was found that alpha-blockers (prazosin, idazoxan, phenoxybenzamine), antiserotoninergics (methysergide, methergoline) and antihistamine (chlorpheniramine, promethazine) also inhibited TNF production indicating that the effectiveness of CPZ in protecting from endotoxin shock is due to its multiple pharmacological activities.

Urinary TNF-binding protein (TNF soluble receptor) protects mice against the lethal effect of TNF and endotoxic shock

We tested the effect of urinary TNF-binding protein (uTBP) on the toxic effect of TNF (0.5 micrograms/mouse, i.v.) in adrenalectomized mice sensitized with IL-1 to increase susceptibility to TNF. In this experimental model, mortality was 67%, but decreased to 13% when uTBP (250 micrograms/mouse, i.v.) was administered simultaneously with TNF. The protective effect of uTBP was dose-dependent, and time course experiments indicated a protective effect when uTBP was administered before or up to one hour after TNF. Some protection was also obtained when uTBP was given three hours after TNF. Urinary TBP improved the survival of mice after a lethal dose of LPS (1.2 mg/mouse, i.p.), suggesting its possible efficacy in the therapy of septic shock or other TNF-mediated pathologies.

Retroperitoneal germ cell tumor in postmenopausal woman

A fifty-four-year-old woman presented with right renal colic and three months later a retroperitoneal tumor was diagnosed. After explorative laparotomy with biopsy, which showed a germ cell tumor, the patient received external beam radiotherapy, but died of metastatic diffusion nine months later. We believe this is a rare occurrence of a germ cell tumor in a postmenopausal woman.

O6-alkylguanine DNA alkyltransferase is induced by human recombinant interferon-alpha A/D in mouse liver

Treatment of C57Bl or BALB/C mice with human interferon-alpha A/D (HuIFN-alpha A/D) significantly increased hepatic levels of the DNA repair enzyme O6-alkylguanine DNA alkyltransferase (AT). The maximum induction was seen 24 h after a single dose of 50-100 micrograms/kg IFN-alpha A/D. No induction was observed in rat liver hepatocytes cultured in vitro. Liver AT was also induced by poly(I:C), which is a potent IFN inducer. By increasing AT levels, IFN could protect against the potentially mutagenic alkylation at guanine O6 position caused by some carcinogens. Moreover this finding suggests a link between immune response and the DNA repair system, possibly acting in concert to defend the body from potentially toxic compounds.

Depression of hepatic drug metabolism in endotoxin-treated and sarcoma-bearing mice

The effect of a single dose of bacterial endotoxin (lipopolysaccharide, LPS) was compared with that of tumor implantation in mice on the activity of several hepatic cytochrome P-450-dependent monooxygenases. These included ethoxycoumarin O-deethylase, p-nitrophenol hydroxylase, aminopyrine N-demethylase, pentoxyresorufin O-depentylase, ethoxyresorufin O-deethylase and testosterone hydroxylase. For this purpose, mice were treated i.p. with 5 micrograms of LPS or implanted in the right paw with S 180 sarcoma. A comparable depression (30-50%) of total microsomal P-450 content as well as of the different P-450 monooxygenase activities tested was observed in LPS-treated mice (24 h after LPS) and in tumor bearing mice (12 days after implantation). The lack of differences in the pattern of depression of microsomal enzymes between LPS-treated and tumor-bearing mice suggests that a common mechanisms might be involved in the depression of P-450 by LPS or S-180 implantation.

Inhibitory effect of recombinant intracellular interleukin 1 receptor antagonist on endothelial cell activation

This investigation was designed to elucidate whether an intracellular version of interleukin 1 receptor antagonist (icIL-1ra) interferes with the action of IL-1 at the level of vascular cells. Recombinant icIL-1ra inhibited the IL-1-induced production of IL-6, IL-8 and monocyte chemotactic protein by human endothelial cells (HEC). Moreover, icIL-1ra inhibited induction of adhesion molecules by IL-1. Endotoxin lipopolysaccharide (LPS), an IL-1 inducer, stimulated a spectrum of functions in EC similar to that activated by IL-1, but icIL-1ra did not interfere with the LPS activation of EC. This observation suggests that induction of extracellular IL-1 is not an important intermediate event in the response of EC to LPS. Unlike LPS-stimulated monocytes, EC exposed to different inducers did not express appreciable levels of IL-1ra mRNA transcripts as assessed by northern blot analysis. IL-1ra produced by mononuclear phagocytes, represents a negative regulator circuit of the action of IL-1 on EC and could be important in the control of vascular participation in inflammation and immunity.

Production and identification of natural monocyte chemotactic protein from virally infected murine fibroblasts. Relationship with the product of the mouse competence (JE) gene

Primary cultures of mouse embryonic fibroblasts and confluent monolayers of mouse fibroblastoid cells (L929) were found to secrete a chemotactic factor specific for monocytes. It biological activity was deduced from both the migration distance under agarose and the number of migrated monocytes in the micropore filter method. The monocyte chemotactic protein (MCP) was inducible in these cells by double-stranded RNA and by infection with virus. In embryonic fibroblasts MCP was also produced in response to the cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF). Under all conditions for induction of MCP tested no production of chemotactic activity for granulocytes could be detected. MCP activity from virally infected L929 cells was concentrated and purified by sequential adsorption to controlled pore glass, heparin-Sepharose chromatography, ion-exchange FPLC and reversed-phase HPLC. Pure MCP was found to occur mainly as a 7-8-kDa protein. Although the mature protein possessed a blocked NH2-terminus, it was identified by enzymatic cleavage and sequence analysis of an internal fragment. The sequence obtained corresponded to a part of the cDNA-derived protein sequence of the murine 'competence' (JE) gene, inducible in fibroblasts by cytokines and virus. In all probability the 7-8-kDa MCP form represents the natural product of the mouse gene JE. Murine MCP can thus be classified in the novel family of small inducible inflammatory proteins.

Protective effect of chlorpromazine on endotoxin toxicity and TNF production in glucocorticoid-sensitive and glucocorticoid-resistant models of endotoxic shock

The present study was designed to define the potential of chlorpromazine (CPZ) as a protective agent against lipopolysaccharide (LPS) toxicity in comparison with glucocorticoids, and to obtain initial correlations with its effects on the levels of tumor necrosis factor (TNF), a pivotal mediator of endotoxic shock. It was found that CPZ protects mice, normal or adrenalectomized, and guinea pigs against lethality of LPS, and inhibited TNF serum levels, like dexamethasone (DEX), a well-known inhibitor of TNF synthesis. CPZ protected against LPS lethality when administered 30 minutes (min) before, simultaneously, or up to 10 min after LPS and was ineffective when given 30 min after LPS, paralleling the inhibitory effect on TNF production. In another experimental model, where mice were sensitized to LPS toxicity by actinomycin D, CPZ significantly inhibited LPS lethality and hepatotoxicity, whereas under these conditions DEX was inactive. These experiments indicate that CPZ has a protective action in both glucocorticoid-sensitive and -resistant models of endotoxic shock.

Chlorpromazine protection against interleukin-1 and tumor necrosis factor-mediated activities in vivo

Interleukin (IL-1) and tumor necrosis factor (TNF) are thought to play a key role in septic shock and inflammation. We had previously shown that chlorpromazine (CPZ) has a protective effect in various models of endotoxic shock and IL-1 toxicity. We have tested the effect of CPZ on several activities of IL-1 in vivo. CPZ (4 mg/kg) inhibited increases in serum corticosterone, triglycerides and serum amyloid A (SAA). Chlorpromazine also antagonized these same effects when they were induced by endotoxin or TNF, suggesting that this activity could be implicated in the protective effect of CPZ in various models of endotoxic shock and IL-1 lethality.

Effects of chlorpromazine on PMN-mediated activities in vivo and in vitro

Polymorphonuclear neutrophils (PMN) play a central role in the acute inflammatory response and functions associated with phagocytosis and bacterial killing, including lysosomal enzyme release and superoxide anion (O2-) generation, are also implicated in tissue injury. We have studied the modulation by chlorpromazine (CPZ) on the effects of lipopolisaccharide (LPS) in vivo in mice. Pretreatment with CPZ (4 mg/kg) and, to lesser extent, promethazine, inhibited LPS-induced hypoferraemia and lethality in mice. We have also observed that CPZ (1-15 microns) inhibited lactoferrin release by PMN in vitro, suggesting that this effect could be responsible for the inhibition of hypoferraemia. We have also evaluated the effect of CPZ on other PMN functions implicated in tissue damage and inflammation, chemotaxis and O2- production. CPZ inhibited both activities, although it had chemokinetic activity per se. These data indicate that CPZ is a modular of PMN functions in vivo and in vitro and this effect could be directly implicated in the protective action of CPZ against endotoxic shock.

Interferon inducers increase O6-alkylguanine-DNA alkyltransferase in the rat liver

We investigated whether treatment with the interferon inducer polyinosinic-polycytidylic acid and other cytokines (interleukin-1, tumor necrosis factor) or the cytokine inducer lipopolysaccharide modified O6-alkylguanine-DNA alkyltransferase (AT) in rat liver. AT levels were determined in liver extracts using N-[3H]methyl-N-nitrosourea alkylated calf thymus DNA as substrate and an HPLC procedure to measure O6-methylguanine. Doses as low as 0.1 mg/kg i.p. of polyinosinic-polycytidylic acid caused a highly significant increase (P less than 0.01) in AT levels in the liver, evident either 24 or 48 h after treatment. Lipopolysaccharide at the dose of 80 micrograms/kg i.p. also induced AT whereas interleukin-1 (60 micrograms/kg) or tumor necrosis factor (60 micrograms/kg) were inactive. Treatment with human recombinant interferon alpha A/D caused a highly significant increase in AT levels, thus confirming the hypothesis that interferon was probably responsible for the observed effect. These results suggest a link between the immune response and DNA repair mechanisms.

Protective effect of chlorpromazine against the lethality of interleukin 1 in adrenalectomized or actinomycin D-sensitized mice

Interleukin 1 (IL-1) and Tumor Necrosis Factor (TNF) are thought to play a key role in septic shock and inflammation. We have tested the effect of dexamethasone (DEX) and chlorpromazine (CPZ) on the lethal effect of IL-1, TNF and endotoxin. Two different experimental models were used to sensitize mice to the lethal effect of IL-1: adrenalectomy and pretreatment with actinomycin D. CPZ (4 mg/kg) was found to protect mice against IL-1 and endotoxin toxicity in all cases, while DEX had a protective effect only in adrenalectomized mice. In contrast to its protective effect against IL-1 and endotoxin, CPZ did not protect mice against TNF. These findings might be useful in the analysis of the differences in the actions of IL-1 and TNF in vivo, and in the development of new drugs preventing their toxicity.

Identification by sequence analysis of chemotactic factors for monocytes produced by normal and transformed cells stimulated with virus, double-stranded RNA or cytokine

A monocyte chemotactic activity was found to be released by various types of cultured human cells after appropriate stimulation: normal diploid fibroblasts, peripheral blood mononuclear cells or monocytes isolated therefrom, and a number of tumor cell lines, including osteosarcoma (MG-63) and hepatoma (Malavu) but not melanoma (Bowes) cells. Cultures of diploid human fibroblasts and these tumor cells stimulated with interleukin (IL) 1 or double-stranded RNA [poly(rI).poly(rC)], or infected with viruses (measles or rubella viruses) were found to produce chemotactic activity for both monocytes and granulocytes. Media collected from fibroblasts treated with E. coli or IL 6 did not contain such activity. Granulocyte and monocyte chemotactic activities were serologically distinct, and could be separated by successive chromatographical procedures. While the granulocyte chemotactic activity of both fibroblasts and MG-63 cells had previously been identified as granulocyte chemotactic protein/IL 8, the monocyte chemotactic activity from MG-63 cells was identified by amino acid sequence analysis as a different protein recently described to be released by human glioma and myelomonocytic cell lines. In view of the similarity in their chromatographical behavior, monocyte chemotactic activities from fibroblasts, MG-63 cells and fresh monocytes can probably be assigned to identical molecules. Cultures of unfractionated peripheral blood cells, however, were found to release an additional monocyte chemotactic protein, identifiable by amino acid sequence analysis as platelet factor 4.

Dexamethasone modulation of in vivo effects of endotoxin, tumor necrosis factor, and interleukin-1 on liver cytochrome P-450, plasma fibrinogen, and serum iron

Treatment of mice with endotoxin (lipopolysaccharide, LPS) and the two LPS-induced monokines, tumor necrosis factor (TNF) and interleukin-1 (IL-1), caused a depression of liver cytochrome P-450 and related drug-metabolizing enzymes, as well as other acute-phase changes including increase in plasma fibrinogen levels and hypoferremia. However, only IL-1, not TNF or LPS, depressed cytochrome P-450 in cultured hepatocytes, suggesting that the effect of TNF in vivo might be mediated by a second mediator. TNF- or LPS-stimulated monocytes released a factor capable of depressing cytochrome P-450 in cultured hepatocytes. This factor was inhibited by anti-IL-1 antiserum, and its synthesis, like that of IL-1, was inhibited by dexamethasone (DEX). Pretreatment of mice with DEX protected against the depression of liver cytochrome P-450 by LPS or TNF but not by IL-1, suggesting that IL-1 directly depresses cytochrome P-450 and that DEX acts by inhibiting IL-1 synthesis in vivo induced by LPS or TNF. However, DEX did not inhibit two other effects of LPS and TNF in vivo: increase of plasma fibrinogen levels and decrease of plasma iron, suggesting that these might not be mediated by IL-1. Therefore, the effect of DEX in vivo, although supporting the hypothesis that depression of liver cytochrome P-450 by LPS and TNF is mediated by IL-1, indicates the existence of IL-1-independent pathways in the acute-phase response.

Depression of liver drug metabolism in sarcoma-bearing mice. Evidence for a circulating factor and dissociation from lipolytic activity

Mice bearing the S-180 sarcoma displayed a depression of liver catalase and cytochrome P-450-dependent enzymes (ethoxycoumarin deethylase, ED) from day 6 following tumor implantation. Injection of serum obtained from tumor-bearing mice into normal mice caused depression of liver ED suggesting that a circulating factor was involved. Tumor-bearing mice did not show any significant change in serum triglycerides and food intake. By contrast, injection of endotoxin, interleukin-1 (IL-1) or tumor necrosis factor (TNF) caused not only a depression in liver ED but also a marked increase in serum triglycerides. To study the possible analogies between cancer-associated circulating factor and monokines, we studied the effect of dexamethasone (a known inhibitor of monokine synthesis) on liver ED activity in tumor-bearing mice. Dexamethasone (DEX) treatment increased (up to 60%) liver ED activity in tumor-bearing mice. We conclude that: (i) a circulating factor is involved in cancer-associated ED depression; (ii) that this mediator is not necessarily identical to TNF or IL-1 and (iii) that DEX reverses the depression of liver ED in cancer, possibly by inhibiting the synthesis, or the effects, of this factor.

Adrenalectomy sensitizes mice to the lethal effects of interleukin 1 and tumor necrosis factor

To clarify the possible role of TNF and IL-1 in endotoxic shock, the lethality of rTNF (human and murine) and IL-1 in adrenalectomized mice was studied. Adrenalectomy, which has long been known to increase the susceptibility to endotoxin, rendered mice susceptible to TNF and IL-1 in terms of mortality. The lethality of endotoxin, TNF, or IL-1 was totally prevented by pretreatment with dexamethasone (minimal effective dose, 0.3 mg/Kg) but not by ibuprofen (10 mg/Kg).

Induction of indoleamine dioxygenase by interferon in mice: a study with different recombinant interferons and various cytokines

Since it is important the availability of a specific marker for interferon induction in vivo, we investigated the effect of different recombinant interferons and various cytokines on indoleamine 2,3-dioxygenase activity. Although with different magnitude, recombinant interferon-alpha A/D (Bgl II) hybrid, interferon-gamma and tumor necrosis factor, all increase the activity of this enzyme, whereas interleukin-1, recombinant interferon-alpha A and interferon-alpha D do not induce this activity in mice lung tissue. Dexamethasone is able to inhibit indoleamine 2,3-dioxygenase induction by lipopolysaccharide or by interferon-alpha A/D but it fails to prevent the induction by interferon-gamma.

Depression of liver drug metabolism and increase in plasma fibrinogen by interleukin 1 and tumor necrosis factor: a comparison with lymphotoxin and interferon

Different recombinant cytokines were studied for their effects on mouse liver in vivo: interleukin 1-alpha and -beta, tumor necrosis factor, lymphotoxin, interferon-alpha A/D and gamma depressed liver cytochrome P450-dependent drug metabolism (measured by ethoxycoumarin deethylase activity) 24 h after treatment, at doses in the microgram range, while IL-2 had no effect on this enzymatic system. Interleukin 1 (both alpha and beta), tumor necrosis factor and lymphotoxin also increased plasma fibrinogen, a marker of liver acute phase inflammatory response. Interferon-gamma and tumor necrosis factor had an additive effect in depressing liver drug metabolism. When tested in vitro on isolated hepatocytes, only interleukin 1 depressed P450-dependent drug metabolism, while all the other cytokines were inactive, thus suggesting that their effect on the liver in vivo is not a direct effect but is mediated by other mediators.