Effects Of Interleukin-1 Alpha Research Articles

Alpha, mu and pi class glutathione S-transferases in human synovium and cultured synovial fibroblasts: effects of interleukin-1 alpha, hydrogen peroxide and inhibition of eicosanoid synthesis.

We describe expression of alpha, mu and pi class glutathione S-transferase (GST) and, CuZn- and Mn superoxide dismutase (SOD) in human synovium and cultured synovial fibroblasts. Immunohistochemical and immunoblotting studies showed synovium and cultured cells expressed pi GST and both isoforms of SOD. Cellular localisation was largely perinuclear. No expression of alpha or mu GST was detected even though polymerase chain reaction analysis showed 4/6 subjects had positive genotypes at the polymorphic, mu class GSTM1 locus. Incubation of cultured synovial fibroblasts with H2O2, IL-1 alpha and the cyclooxygenase and lipoxygenase inhibitor, Tenidap, did not induce expression of alpha, mu or pi GST though treatment with IL-1 alpha caused a marked increase in the expression of Mn SOD.

Effect of interleukin-1 alpha on lipoprotein lipids in cynomolgus monkeys: Comparison to tumor necrosis factor

Acute inflammation is associated with changes in lipoprotein metabolism. Cytokines are thought to mediate the metabolic effects of the inflammatory process. This study was undertaken to compare the effects of interleukin-1α (IL-1α) to tumor necrosis factor (TNF) on lipoprotein metabolism in non-human primates. Recombinant human IL-1α (100 μg/kg), TNFα (20 μg/kg) and lipopolysaccharide (20 μg/kg) were injected into cynomolgus monkeys. Lipoprotein concentrations, plasma activities of post-heparin lipase (PHLA) and lecithin:cholesterol acyltransferase (LCAT) were measured prior to and 24 and 48 h after, injection. All three injectates caused afebrile response in the animals. Interleukin-1α had no effect on plasma lipoprotein concentrations, composition of lipoproteins or enzyme activity. In contrast, injection of TNF caused significant changes in lipoprotein concentrations. There was a 38% increase in plasma triacylglycerol and 30% decrease in plasma cholesterol at 48 h after injection. Concentrations of apolipoproteins A-I and B were decreased 20% and 44%, respectively, at 48 h. Compositional analyses of lipoprotein particles after TNF injection showed that both the LDL and HDL particles had decreased content of cholesterol ester and increased triacylglycerol after injection, and plasma activities of PHLA and LCAT were decreased. These changes were qualitatively similar to those seen after LPS injection. These data suggest that, unlike TNF, IL-1α is not an important mediator of the inflammatory process on lipoprotein metabolism in cynomolgus monkeys.

Metabolism of articular cartilage in the presence of interleukin-1-alpha, its inhibitor, and blood serum

The study was made of the effect which interleukin receptor antagonist protein (IRAP) and bovine serum have on interleukin-1 alpha (IL1a) activity in cartilage culture of young bulls. It was established that IL1a leads to cartilage degradation as shown by an increase of sulphated glycosaminoglycans (sGAG) in culture medium and their decrease in tissue, inhibition of proteoglycan (PG) synthesis by chondrocytes. This effect of IL1a is suppressed by IRAP. In serum-free culture the cartilage tissue produced proteoglycans in much less quantities. In these conditions IL1a stimulated chondrocytes, cytokine did not respond to IRAP.

Interleukin-1-induced alterations in glomerular proteoglycans: biochemical and tissue autoradiographic aspects.

The effect of interleukin-1 alpha (IL-1) on the synthesis of glomerular basement membrane heparan sulfate-proteoglycan (HS-PG) was investigated. An ex vivo recirculating organ perfusion system was used. Kidneys were perfused with a medium containing (35S) sulfate and IL-1 (0.625 to 6.25 ng/mL). After radiolabeling was performed, a small cortical piece was saved for tissue autoradiography; the remaining kidney and perfusion medium were used for biochemical studies. Renal cortices were dissected out, and glomeruli were isolated; the PG were extracted and characterized. With exposure to IL-1 (5 ng/mL), an approximately twofold increase of the radioactivity in the glomerular fraction was noted. The increase was unaffected by indomethacin treatment. By Sepharose CL-6B chromatography, a single peak of radioactivity with Kav = 0.25 (macromolecular form of PG) was observed in the control group. The IL-treated group had two peaks of radioactivity with Kav = 0.25 and 0.45: the first peak contained PG, and the second peak consisted of free glycosaminoglycan (GAG) chains. Elution profiles of hydrolyzed tissue GAG chains were similar. No change in the ratio of chondroitin to heparan sulfate was observed. By DEAE-Sephacel chromatography, the glomerular PG/GAG of the IL-treated group eluted at a relatively lower salt concentration, suggesting a change in the charge density characteristics. No differences in the elution profiles of media PG/GAG were observed. (35S)methionine labeling of proteins showed no significant increase of the total radioincorporation in the IL-treated group. Immunoprecipitation studies revealed an approximately 88% increase in the de novo synthesis of PG. Tissue autoradiography revealed an approximately twofold increase of (35S) sulfate radioactivity over the glomerular mesangium, epithelium, and basement membranes. These results indicate that IL-1 enhances the synthesis of the macromolecular form of PG and the generation of free chains. Conceivably, such alterations may lead to defective macromolecular interactions among various components of the glomerular basement membrane and compromise the integrity of the ultrafiltration unit of the glomerulus.

Inhibition of interleukin-1-alpha-induced nitric oxide synthase in vascular smooth muscle and full reversal of interleukin-1-alpha-induced hypotension by N omega-amino-L-arginine.

Interleukin-1-alpha (IL-1) is a cytokine with potentially therapeutic immunoproliferative and tumoricidal activities. Preliminary clinical studies suggest that use of IL-1 may be restricted by dose-limiting hypotension. The purpose of this study was to investigate the role of nitric oxide (NO.) as a possible mediator of this hypotension. Cytokine-treated rat aortic smooth muscle cells were assayed for nitrite production, a stable breakdown product of nitric oxide. Nitric oxide synthase from smooth muscle cells was partially characterized in cytosol preparations using a novel Fe(2+)-myoglobin method to test for nitric oxide production. To determine the role of NO. on the immunorestorative and antineoplastic activity of IL-1, N omega-amino-L-arginine (NAA) or N omega-monomethyl-L-arginine (NMA), inhibitors of nitric oxide synthase, were added to either cultures of IL-1-dependent T cells or A375 melanoma cells exposed to IL-1. To investigate the effects of NAA in vivo, pentobarbital anesthetized dogs, which were made hypotensive by administration of IL-1, received a single intravenous bolus dose of NAA. The effects of NAA were then reversed by the administration of L-arginine. Our results show that cultured IL-1-activated rat aortic smooth muscle cells synthesize nitric oxide, a potent vasodilator. Induction of nitric oxide synthase is augmented by interferon-gamma and blocked by IL-1 receptor antagonist and by inhibitors of RNA or protein synthesis. Nitric oxide synthesis by IL-1-activated smooth muscle cells is inhibited by NAA, NMA, and N omega-nitro-L-arginine (NNA) with ED50 (i.e., effective dose for 50% inhibition) values of 20, 60, and 1000 microM, respectively; this rank order of inhibition is characteristic of an agonist-unregulated, inducible isoform of nitric oxide synthase. In smooth muscle cells, inhibition of NO. synthesis by NAA is reversed by excess L-arginine. Consistent with the induction of unregulated NO. synthesis in vascular smooth muscle in vivo, administration of IL-1 (50 micrograms/kg) to dogs caused a 33.5% decrease in systemic vascular resistance and a 28% decrease in blood pressure within 3 hours. Subsequent administration of NAA (20 mg/kg) rapidly and completely reversed the hypotension and increased systemic vascular resistance; these effects of NAA were reversed by L-arginine. Neither the immunoproliferative nor the tumoricidal activity of IL-1 was diminished by NAA. Our results indicate that (a) vascular smooth muscle is a likely source as well as a target of IL-1-induced NO. synthesis, causing vasodilatation and hypotension, (b) nitric oxide synthase inhibitors can fully reverse this hypotension, and (c) the therapeutically useful properties of IL-1 are not diminished by nitric oxide synthase inhibitors. Administration of inhibitors of nitric oxide synthase can reverse the pathological cardiovascular effects of IL-1 at concentrations that do not interfere with the potentially useful immunoproliferative or tumoricidal effects of this cytokine. In the context of the current clinical trials of IL-1, this finding would represent a very significant advantage.

Induction of interleukin-1 beta production in human dermal fibroblasts by interleukin-1 alpha and tumor necrosis factor-alpha. Involvement of protein kinase-dependent and adenylate cyclase-dependent regulatory pathways.

It has previously been demonstrated that interleukin-1 (IL-1) is expressed in a variety of fibroblast cell lines. In this study, we investigated the mechanisms involved in the regulation of IL-1 beta production by cultured human dermal fibroblasts. We have shown that IL-1 beta is constitutively expressed as a cell-associated form, with no soluble form detectable in control cell or in stimulated cell supernatants. IL-1 alpha and tumor necrosis factor-alpha (TNF-alpha) exerted a dose-dependent stimulation on the production of the cell-associated IL-1 beta, as estimated using a specific enzyme linked immunosorbent assay (ELISA). As expected, this effect was accompanied by a huge release of prostaglandin E2 (PGE2) and a transient rise in intracellular cyclic AMP. Furthermore, IL-1 beta production was elevated to a lesser extent by the addition of increasing concentrations of the protein kinase C activator phorbol myristate acetate or by low concentration (0.001 microgram/ml) of PGE2. In contrast, higher concentrations (0.1 and 1 micrograms/ml) of PGE2, as well as exogenous dibutyryl-cyclic AMP, were clearly inhibitory. H7, an inhibitor of protein kinases also reduced the stimulatory effect of IL-1 alpha and TNF-alpha. Together with the results obtained with phorbol myristate acetate, these data suggest that protein kinase C may play a role in the upregulation of IL-1 beta expression in normal skin fibroblasts. The addition of indomethacin not only suppressed prostaglandin synthesis, but also dramatically reduced cyclic AMP formation, probably because the PGE2-induced stimulation of adenylate cyclase was abolished. This resulted in a strong potentiation of the stimulatory effect of IL-1 alpha and TNF-alpha, supporting the role of both the cyclooxygenase and adenylate cyclase pathways in the endogenous downregulation of IL-1 beta induction by the two cytokines studied.

Studies of the Modulation of MHC Antigen and Cell Adhesion Molecule Expression on Human Dermal Microvascular Endotheliam Cells

Interactions between leukocytes and endothelial cells, particularly in the microvasculature, are important for the initiation and regulation of tissue inflammation. These interactions are regulated by the recognition of specific cell adhesion molecules (CAM) on both leukocytes and endothelial cells. In this study, we examined the modulation of cell surface expression of MHC antigens and the CAM intercellular adhesion molecule 1 (ICAM-1), lymphocyte function antigen 3 (LFA-3), and CD44 on human dermal microvascular endothelial cells (HDMEC) both grown in monolayers and differentiated into capillary-like structures on the basement membrane-like substrate matrigel. HDMEC grown in monolayers or differentiated on matrigel express comparable cell surface MHC class I, LFA-3, CD44, and ICAM-1. ICAM-1, but not LFA-3 or CD44, was increased in expression in a dose- and time-dependent manner by interleukin 1 (IL-1) alpha, tumor necrosis factor (TNF) alpha, lipopolysaccharide (LPS), or interferon (IFN) gamma. Comparable upregulation was observed both in cells grown in monolayers and cells differentiated on matrigel. IL-1 alpha, TNF alpha, and LPS increased ICAM-1 expression on average 100-200% whereas IFN gamma was somewhat less potent. Comparative studies with human umbilical vein endothelial cells (HUVEC) demonstrated consistently lower levels of ICAM-1 expression on HUVEC, but greater increases after cytokine stimulation. Pretreatment with dexamethasone or transforming growth factor (TGF) beta did not affect baseline expression of ICAM-1 or inhibit upregulation of ICAM-1 on HDMEC by IL-1 alpha, TNF alpha, LPS, or IFN gamma. Both IFN gamma and TNF alpha, but not IL-1 alpha increased MHC class I expression, whereas only IFN gamma induced the expression of HLA-DR on HDMEC. The effect of IL-1 alpha, TNF alpha, or IFN gamma was inhibited by antibody to the specific cytokine, but was unaffected by antibody to other cytokines. Additionally, IFN alpha or beta inhibited upregulation of HLA-DR by IFN gamma, but had no effect on the increased MHC class I or ICAM-1 expression mediated by this cytokine. These data demonstrate that the expression of CAM and MHC antigens on small vessel-derived endothelial cells is different from that observed on large-vessel HUVEC, is regulated by the presence of multiple cytokines operating via distinct pathways, and the expression and regulation of these proteins appear to be similar on cells that have been grown in monolayers to those morphologically differentiated into blood vessel-like structures.

Interleukin-1 alpha-induced changes in androgen and cyclic adenosine 3',5'-monophosphate release in adult rat Leydig cells in culture.

Interleukin-1 (IL-1) has been proposed as a paracrine regulator of testicular function. The effect of this cytokine on adult rat Leydig cells in primary culture was investigated. Interstitial cells were purified on a two-step Percoll gradient and cultured in the presence or absence of recombinant human IL-1 alpha (IL-1 alpha). The presence of IL-1 alpha in the culture media resulted in a dose-dependent increase in 24-h basal androgen release (half-maximal effective concentration = 40-50 U/ml). The stimulatory effect of IL-1 alpha peaked on days 3 and 4, and was often still significant after 6 days of culture. Removal of IL-1 alpha was followed by a return of basal androgen release to control levels within 3 days. In contrast, cells treated with IL-1 alpha (100 U/ml) for 3 days released significantly less androgen (per 4 h) in response to 1-100 ng LH/ml than control cells. A similar inhibitory effect on the response to dibutyryl cAMP and pregnenolone was observed. Under basal conditions, IL-1 alpha-treated cells released significantly more cAMP than did control cells. In contrast, the increase in cAMP release seen with LH-stimulated cells was significantly inhibited by treatment with IL-1 alpha. These results suggest that IL-1 alpha has a dual effect on adult rat Leydig cells in culture. It stimulates basal but inhibits LH-induced androgen release with parallel changes in cAMP levels. An additional inhibitory effect appears to lie at the level of the 17 alpha-hydroxylase/C17-20 lyase enzyme.

Tumor necrosis factor-alpha and interleukin 1-alpha regulate transferrin receptor in human diploid fibroblasts. Relationship to the induction of ferritin heavy chain.

We have studied transferrin receptor expression in MRC5 human fibroblasts in response to tumor necrosis factor-alpha (TNF, cachectin) or interleukin 1-alpha (IL-1). Treatment of exponentially growing MRC5 cells with these cytokines led to a 3-4-fold increase in transferrin receptor mRNA and a coordinate increase in transferrin receptor protein by 24 h. Under these conditions, stimulation of [3H]thymidine incorporation was minimal, suggesting that the induction of transferrin receptor by TNF and IL-1 is mediated by a growth-independent regulatory mechanism. A study of the time course of this response showed that cytokine-mediated increases in transferrin receptor mRNA and protein proceeded after a lag of 12-24 h. A simultaneous analysis of the effects of TNF and IL-1 on ferritin in MRC5 cells was also performed. Ferritin L mRNA levels were unchanged. However, induction of ferritin H mRNA was seen within 4 h, preceding the induction of the transferrin receptor. The synthesis of ferritin H (but not ferritin L) protein peaked at 8 h after TNF or IL-1 treatment, followed by a rapid decrease in both ferritin H and L protein synthesis. As ferritin H synthesis declined, levels of transferrin receptor protein increased, reaching a maximum by 24 h. These results suggest that the cytokine-dependent induction of ferritin H and subsequent increase in the transferrin receptor are related and possibly interdependent events. This study demonstrates that the complex role of TNF and IL-1 in iron homeostasis includes modulation of the transferrin receptor.

Tumor necrosis factor and interleukin 1 alpha increase vascular endothelial permeability.

Endotoxic shock is associated with acute vascular endothelial injury resulting in edema. Tumor necrosis factor (TNF) and interleukin 1 (IL-1) are cytokines produced by endotoxin-stimulated mononuclear phagocytes that are potential mediators of endotoxic shock. In this study, we investigated the effects of TNF and IL-1 alpha on vascular endothelial cell permeability in vitro. The movement of radiolabeled macromolecules of different sizes (57Co-vitamin B12, 125I-cytochrome c, and 131I-albumin; 6.5-35A) across bovine aortic endothelial cell monolayers was measured after exposure to these cytokines. TNF induced a time- and dose-dependent increase in endothelial cell monolayer permeability that was enhanced in the presence of serum. The peak increase was noted after 12 h of incubation with less alteration of permeability with longer incubations. IL-1 alpha caused a similar time-dependent increase in endothelial cell monolayer permeability, but the peak effect of IL-1 alpha was seen after 24 h. Therefore the increased permeability seen with TNF cannot be explained by release of endogenous IL-1 alone. Neither TNF nor IL-1 alpha increased release of [14C]adenine, and the only effect on lactate dehydrogenase release was a small, but statistically significant, increase after 24 h of incubation. From these studies, we conclude that TNF and IL-1 alpha directly increase vascular endothelial cell permeability in vitro and speculate that these cytokines may be involved in the acute vascular endothelial injury associated with endotoxic shock.

Effects of Protein Kinase-C-Related Adrenocorticotropin Secretagogues and Interleukin-1 on Proopiomelanocortin Gene Expression in Rat Anterior Pituitary Cells*

To examine the effects of the cAMP-independent protein kinase-C system and interleukin-1 (IL-1) on secretion of ACTH and POMC gene expression in cultured rat anterior pituitary (AP) cells, AP cells were incubated with CRF, 8-bromo-cAMP, arginine vasopressin, angiotensin II, norepinephrine, and phorbol 12-myristate 13-acetate. After 15 h of incubation, CRF and 8-bromo-cAMP increased both ACTH release and the POMC mRNA level. Arginine vasopressin, angiotensin II, norepinephrine, or phorbol 12-myristate 13-acetate stimulated ACTH release but failed to increase basal or CRF-stimulated POMC mRNA levels. Human recombinant IL-1 alpha and -beta increased neither ACTH release nor POMC mRNA levels after 3 h of incubation. After 15 h of incubation, 100 pM to 10 nM IL-1 alpha and -beta increased ACTH release. However, POMC mRNA levels were significantly elevated only by 10 pM IL-1 beta. These results suggest that the CRF-cAMP system plays a major role in both ACTH release and expression of the POMC gene in AP cells, but the cAMP-independent protein kinase-C system contributes only to ACTH release; that acute stimulation of ACTH release from AP with IL-1 administration is not due to direct action of IL-1 at the pituitary level; that chronic exposure of AP cells to IL-1 alpha or -beta can stimulate ACTH release; and that the direct effects of IL-1 alpha and -beta on POMC gene expression, if any, seem to be minimal.

Interleukin-1α Enhances the In Vitro Survival of Purified Murine Granulocyte-Macrophage Progenitor Cells in the Absence of Colony-Stimulating Factors

Interleukin-1 (IL-1), recently identified as hemopoietin-1, affects hematopoiesis by presumably direct and indirect mechanisms. IL-1 stimulates primitive hematopoietic stem cells to express receptors for the granulocyte-macrophage colony-stimulating factors (GM-CSFs) and stimulates CSF release from accessory cells. We used highly purified murine granulocyte-macrophage progenitor cells (CFU-GM, up to 92% cloning efficiency) to assess the effects of IL-1 alpha on the proliferation, differentiation, and survival of these cells. The results demonstrated that IL-1 alpha does not directly influence the proliferation or differentiation of purified CFU-GM in the presence of plateau concentrations of purified natural or recombinant CSFs, and IL-1 alpha lacks intrinsic CSF activity of its own. CSF deprivation studies showed that IL-1 alpha rapidly (within one hour) promoted CFU-GM survival in the absence of CSF. This enhanced survival stimulated by IL-1 alpha was observed with CFU-GM responding to purified recombinant GM-CSF, natural M-CSF, recombinant G-CSF, recombinant IL-3, or IL-3 in WEHI-conditioned medium, and no effect on the pattern of CFU-GM differentiation occurred in cultures incubated with IL-1 alpha in the absence of CSF. The IL-1 alpha effects on CFU-GM are probably due to a direct action on progenitor cells because the presence or absence of accessory cells did not alter the results and concentrations of the CSFs that were too low to stimulate the proliferation of CFU-GM could not mimic the IL-1 alpha effect on CFU-GM survival.

Interleukin-1 alpha enhances the in vitro survival of purified murine granulocyte-macrophage progenitor cells in the absence of colony- stimulating factors

Interleukin-1 (IL-1), recently identified as hemopoietin-1, affects hematopoiesis by presumably direct and indirect mechanisms. IL-1 stimulates primitive hematopoietic stem cells to express receptors for the granulocyte-macrophage colony-stimulating factors (GM-CSFs) and stimulates CSF release from accessory cells. We used highly purified murine granulocyte-macrophage progenitor cells (CFU-GM, up to 92% cloning efficiency) to assess the effects of IL-1 alpha on the proliferation, differentiation, and survival of these cells. The results demonstrated that IL-1 alpha does not directly influence the proliferation or differentiation of purified CFU-GM in the presence of plateau concentrations of purified natural or recombinant CSFs, and IL- 1 alpha lacks intrinsic CSF activity of its own. CSF deprivation studies showed that IL-1 alpha rapidly (within one hour) promoted CFU- GM survival in the absence of CSF. This enhanced survival stimulated by IL-1 alpha was observed with CFU-GM responding to purified recombinant GM-CSF, natural M-CSF, recombinant G-CSF, recombinant IL-3, or IL-3 in WEHI-conditioned medium, and no effect on the pattern of CFU-GM differentiation occurred in cultures incubated with IL-1 alpha in the absence of CSF. The IL-1 alpha effects on CFU-GM are probably due to a direct action on progenitor cells because the presence or absence of accessory cells did not alter the results and concentrations of the CSFs that were too low to stimulate the proliferation of CFU-GM could not mimic the IL-1 alpha effect on CFU-GM survival.

Separate but complementary roles for the two forms of interleukin 1 in the growth of transformed human B lymphoblasts.

Epstein-Barr virus (EBV)-transformed human B cells were seeded at densities below their capacity for autostimulatory growth and the effects of interleukin 1-alpha (IL-1-alpha), interleukin 1-beta (IL-1-beta) and B-cell growth factor (BCGF) were studied. When added separately, IL-1-alpha was able to support the growth of EBV-transformed B cells, as was BCGF. In contrast, IL-1-beta was unable to support the growth of these cells but was able to synergize with IL-1-alpha to promote cell growth. Further, the actions of BCGF and IL-1-alpha were seen to be synergistic, while those of BCGF and IL-1-beta were not. The secretion of immunoglobulin was not affected by these reagents. These findings suggest separate, but complementary roles for the two forms of human IL-1 in B-cell growth.

Antitumor effect of recombinant human interleukin 1 alpha against murine syngeneic tumors.

Interleukin 1 (IL1) has been suggested to have antitumor activity but there is no clear-cut evidence of an in vivo antitumor effect of pure IL1. In this work, the antitumor effect of purified recombinant human IL1 alpha (rHu-IL1 alpha) was assessed on murine tumors transplanted intradermally in syngeneic female mice. rHu-IL1 alpha inhibited the growth of Meth A sarcoma in BALB/c mice, B16 melanoma in C57BL/6 mice and colon 26 adenocarcinoma in CDF1 mice, as well as the spontaneous pulmonary metastasis of Lewis lung carcinoma in BDF1 mice, at intratumoral (itu), intramuscular (im), and/or intravenous (iv) doses ranging from 1 to 30 micrograms/mouse. The antitumor effect of rHu-IL1 alpha was generally dose- and route-dependent, being highest by the itu route, followed by the im and iv routes in that order. Palpable 7-day-old Meth A sarcoma was completely regressed in some mice given rHu-IL1 alpha itu once at doses of 10-30 micrograms/mouse (cured ratio; 71-100%), once a day for 3 days at doses of 3-30 micrograms/mouse (57-86%) or once a day for 7 days at doses of 1-10 micrograms/mouse (14-100%). Palpable 7-day-old B16 melanoma was also regressed completely in some mice given seven itu doses of 10-30 micrograms/mouse (14-86%). One-day-old Meth A sarcoma was more sensitive to rHu-IL1 alpha than 7-day-old Meth A sarcoma. There was no macroscopic sign of inflammation at the site of injection of rHu-IL1 alpha. These results show that rHu-IL1 alpha has antitumor activity in vivo and is worthy of further study as a potential antitumor agent.