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J E Sims

Publications and source records attributed to J E Sims.

At least 37 records · Page 2Linked to original sources
PubMed1996

Inhibition of interleukin-1 responsiveness by type II receptor gene transfer: a surface "receptor" with anti-interleukin-1 function.

The hypothesis that the type II receptor (RII) acts as a decoy for interleukin-1 (IL-1) was tested by gene transfer in cells expressing only the type I receptor (8387 fibroblasts). RII-transfected cells showed defective responsiveness to IL-1 in terms of NFkappaB activation, cytokine gene expression and production. Blocking monoclonal antibodies against RII restored the capacity of RII-transfected cells to respond to IL-1 beta. Hence defective IL-1 responsiveness of RII-transfected cells requires surface expression of the molecule. RII-transfected cells showed normal responsiveness to TNF, which shares functional properties and elements in the signal transduction pathway with IL-1. Cells transfected with a deletion mutant of RII missing 26 of 29 amino acids of the cytoplasmic portion of the molecule showed impaired responsiveness to IL-2. Cells transfected with full-length or the cytoplasmic deletion mutant of RII released copious amounts of RII in the supernatant. However, transfected cells showed defective responsiveness to brief exposure to IL-1, in the absence of measurable released RII. These results indicate that impairment of the responsiveness to IL-1 following RII gene transfer was dependent upon surface expression of the molecule, specific for IL-1 and unaffected by truncation of the cytoplasmic portion. Thus, the type II "receptor" is a decoy surface molecule, regulated by antiinflammatory signals, whose only known function is to capture and block IL-1.

Base Sequence↗
PubMed1996

Regulated expression and release of the IL-1 decoy receptor in human mononuclear phagocytes.

The aim of this study was to investigate the expression and release of the IL-1 type II decoy receptor (R) in mononuclear phagocytes, which play a central role in immune and chronic inflammatory reactions. Human monocytes expressed both type I and type II R transcripts, the latter being two- to threefold more represented. By cross-linking and Ab blocking, the predominant surface IL-1-binding molecule was the decoy RII. IL-4, IL-13, and dexamethasone induced RI and RII transcripts and augmented the number of IL-1-binding sites with no modification of Kd values. The induced surface receptor was identified as the decoy RII. These stimuli induced the release of a soluble R with a m.w. of approximately 60 kDa, of which N-glycosylation contributed 22 kDa compared with 45 kDa released from polymorphonuclear leukocytes, of which N-glycosylation contributed 15 kDa. IL-13 and dexamethasone induced a release of 24 ng/ml/2 x 10(7) cells (from 8.7 to 43.2 ng/ml) and 25.6 ng/ml/2 x 10(7) cells (from 9.7 to 36.8 ng/ml) of decoy RII in 18 h, respectively (six donors). Thus, for instance, IL-13-treated (18 h) cells expressed 3.5 x 10(3) sites/cell and released 12 x 10(3) decoy RII/cell. The released decoy RII from monocytes bound IL-1apha and IL-1 receptor antagonist 30- and 2-fold less avidly than IL-1beta, respectively. In vitro-matured, monocyte-derived macrophages showed higher levels of surface expression and release of the IL-1 decoy RII. The results show that, on exposure to diverse molecules with anti-inflammatory properties, mononuclear phagocytes express and release copious amounts of a novel version of the soluble IL-1 decoy RII.

Dexamethasone↗
PubMed1996

T1/ST2 signaling establishes it as a member of an expanding interleukin-1 receptor family.

Through data base searches, we have discovered new proteins that share homology with the signaling domain of the type I interleukin-1 receptor (IL-1RI): human "randomly sequenced cDNA 786" (rsc786), murine MyD88, and two partial Drosophila open reading frames, MstProx and STSDm2245. Comparisons between these new proteins and known IL-1RI homologous proteins such as Toll, 18-Wheeler, and T1/ST2 revealed six clusters of amino acid similarity. We tested the hypothesis that sequence similarity between the signaling domain of IL-1RI and the three mammalian family members might indicate functional similarity. Chimeric IL-1RI receptors expressing the putative signaling domains of T1/ST2, MyD88, and rsc786 were assayed by three separate IL-1 responsive assays, NF-kappaB, phosphorylation of an epidermal growth factor receptor peptide, and an interleukin 8 promoter-controlled reporter construct, for their ability to transduce an IL-1-stimulated signal. All three assays were positive in response to the T1/ST2 chimera, while the MyD88 and rsc786 chimeras failed to respond. These data indicate that the sequence homology between IL-1RI and T1/ST2 indicates a functional homology as well.

Amino Acid Sequence↗
PubMed1996

Cloning of a putative ligand for the T1/ST2 receptor.

T1/ST2 is a receptor-like molecule homologous to the type I interleukin-1 receptor. Despite this sequence similarity, we have been unable to demonstrate binding of T1/ST2 to any of the three interleukin-1 species. In searching for a ligand for T1/ST2, we have cloned a cell surface protein to which it binds. This protein is unable to initiate signal transduction by the T1/ST2 receptor in several in vitro assays.

3T3 Cells↗
PubMed1996

IL-1Rrp is a novel receptor-like molecule similar to the type I interleukin-1 receptor and its homologues T1/ST2 and IL-1R AcP.

A novel member of the interleukin-1 receptor family has been cloned by polymerase chain reaction using degenerate oligonucleotide primers derived from regions of sequence conservation, using as template a yeast artificial chromosome known to contain both interleukin-1 (IL-1) receptors and T1/ST2. The new receptor, called IL-1 receptor-related protein or IL-1Rrp, fails to bind any of the known IL-1 ligands. A chimeric receptor, in which the IL-1Rrp cytoplasmic domain is fused to the extracellular and transmembrane regions of the IL-1 receptor, responds to IL-1 following transfection into COS cells by activation of NFkappaB and induction of IL-8 promoter function.

Amino Acid Sequence↗
PubMed1996

Three distinct promoters direct transcription of different 5' untranslated regions of the human interleukin 1 type I receptor: a possible mechanism for control of translation.

The 5' untranslated regions (UTR) of the human interleukin 1 (IL-1) type I receptor (IL-1RI) are encoded by one common exon (exon 2) but one of three distinct exons 1 (termed exon 1A, 1B, and 1C). These exons span approximately 50 Kb of genomic DNA. Exons 1A and 1B have multiple transcriptional initiation sites, whereas the promoter for exon 1C uses a single start site. There are no "TATA' or "CAAT' boxes, indicating that these promoters belong to the family of housekeeping gene promoters. Computer sequence analysis of exons 1A, 1B, and 1C predicts the potential to form stable secondary structures (delta G degrees 1A = -72.2 Kcal/mol, delta G degrees 1B = -125.8 Kcal/mol, delta G degrees 1C = -255.4 Kcal/mol). Exon 1C appears to be the most stable whereas exon 1A would yield a mRNA species more likely to be translated than those derived from exon 1B or 1C. The 5' UTR of exon 1C is also rich (75%) in GC which might inhibit expression. Therefore, we studied the effect of exon 1C on chloramphenicol acetyltransferase (CAT) activity. Deletion of 183 or 296 base pairs from this GC rich region was shown to increase CAT activity. In addition, insertion of a GC-rich fragment of exon 1C inhibited CAT activity driven by SV40 promoter. These results suggest that the 5' UTR exon 1C of the human IL-1RI may exert a suppressive effect on the translation of IL-1RI transcripts.

Base Sequence↗
PubMed1996

Modulation of osteoclast-activating factor activity of multiple myeloma bone marrow cells by different interleukin-1 inhibitors.

We have studied the effects of several interleukin-1 (IL-1) inhibitors--IL-1 receptor antagonist (IL-1ra), soluble IL-1 receptor (sIL-1R) types I and II, and neutralizing monoclonal antibody (mAb) specific for IL-1 receptor type I--on the osteoclast-activating factor (OAF) activity of recombinant IL-1beta and of culture supernatants of unfractionated bone marrow mononuclear cells from multiple myeloma (MM) patients. The latter activity sharply correlated with the IL-1 content of culture supernatants (r = 0.949; p < 0.001). IL-1ra and sIL-1R types I and II had a clear-cut modulating effect on the OAF activity of IL-1beta at saturating doses (2-10 ng/mL); their effect was evident at 2 ng/mL and was dose-dependent over a large range of concentrations. Similarly, the three reagents neutralized the OAF activities of all MM cell supernatants in a dose-dependent fashion and completely abolished them when tested at the fixed concentration of 5 nM. The bone-resorbing activity of tumor necrosis factor-alpha (TNF-alpha) or lymphotoxin (LT), tested alone or added to MM cell supernatants, was affected not at all by IL-1ra and only minimally by sIL-1R types I and II, suggesting that little or no endogenous IL-1 was produced by the rat cells in the assay under TNF-alpha or LT stimulation. Consistent with these findings, PGE2 production elicited by IL-1beta or IL-1-rich supernatants in the rat long-bone assay was abolished by each reagent. Also, mAbs to the IL-1R p80 (type I) chains could modulate the effects of IL-1--recombinant or plasma cell-derived--in the OAF assay, but their activity was markedly less pronounced when compared with the IL-1 inhibitors, since they could never completely abolish bone resorption. Taken together, these findings demonstrate that inhibition of IL-1 interaction with cognate surface receptors on bone cells effectively counteracts its biologic activity. The findings also strongly indicate that OAF activity in conditioned medium of unfractionated myeloma bone marrow cells is predominantly, if not solely, related to IL-1beta.

Animals↗
PubMed1995

Genomic organization of the type I and type II IL-1 receptors.

Genomic clones spanning the human type I and type II interleukin-1 receptor loci have been isolated. Approximately 75 kb of genomic DNA is required to encode the type I receptor, and approximately 38 kb to encode the type II receptor. In each case, the receptor coding region is contained in only about 20 kb of DNA, with most of the rest of each locus representing the distance between the two (type II receptor) or three (type I receptor) presumptive promoters which drive transcription. The virtually identical location of introns within the ligand-binding portion of the coding regions reinforces the presumption that the two receptors derive from a common ancestor. Yeast artificial chromosomes (YACs) have been isolated which contain the two IL-1 receptors. One of the YACs also contains the T1/ST2 IL-1 receptor-related gene. The relative map position of these three genes has been determined.

Base Sequence↗
PubMed1994

Elevated levels of shed type II IL-1 receptor in sepsis. Potential role for type II receptor in regulation of IL-1 responses.

Two types of cellular IL-1Rs have been characterized and cloned from both human and murine sources. The type II IL-1R has a very short cytoplasmic domain and does not seem to participate in IL-1 signaling. We demonstrate that type II IL-1Rs are released from the surface of neutrophils in response to treatment with TNF or endotoxin. In addition, serum from patients with sepsis syndrome contains elevated levels of soluble type II IL-1Rs. Neutrophils isolated from patients with sepsis have greatly enhanced expression of type II IL-1R mRNA and cell surface receptors and are therefore a likely source for the shed receptors in serum. Of the three forms of IL-1, soluble type II IL-1R binds IL-1 beta with highest affinity and also selectively inhibits IL-1 beta activity. We propose that increased cell surface expression and rapid release of preformed type II IL-1R from neutrophils, as a soluble IL-1 beta binding protein, represents a mechanism that has evolved for regulating IL-1 activity in sepsis.

Blotting, Northern↗
PubMed1994

Binding of IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist by soluble IL-1 receptors and levels of soluble IL-1 receptors in synovial fluids.

These studies have examined the binding of the three IL-1 ligands, IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist (IL-1 ra), to soluble forms of types I and II IL-1Rs (sIL-1RI and sIL-1RII). This interaction was measured in direct binding experiments, in which the ligands bound to immobilized sIL-1R, and in inhibition experiments, in which sIL-1R in solution inhibited the binding of IL-1 ligands to immobilized sIL-1R. In addition, the effects of sIL-1R on the detection of IL-1 ligands by ELISA were examined. Finally, levels of sIL-1R in synovial fluid samples were determined, and their effects on measurement of IL-1 in these samples were estimated. IL-1 beta bound more avidly to sIL-1RII than IL-1 alpha or IL-1ra, primarily because of a slow dissociation rate. In contrast, IL-1 ra bound more avidly than IL-1 alpha or IL-1 beta to sIL-1RI, again because of a slow dissociation rate. sIL-1RII and sIL-1RI inhibited the detection of IL-1 beta and IL-1ra, respectively, by ELISA. Low levels of sIL-1RI (approximately 1.0-2.5 ng/ml) were present in all synovial fluids, irrespective of the degree of inflammation, and were correlated inversely with the levels of measured IL-1ra. In contrast, higher levels of sIL-1RII (approximately 10-20 ng/ml) were found in inflammatory synovial fluids and were not correlated with IL-1ra levels. IL-1 beta could not be detected in any synovial fluid. These results suggest that some IL-1 beta and IL-1ra may be bound in vivo to sIL-1RII and sIL-1RI, respectively, leading to underestimations of cytokine concentrations in body fluids when measured by ELISA.

Animals↗
PubMed1994

The two interleukin-1 receptors play different roles in IL-1 actions.

The proinflammatory cytokine interleukin-1 binds to two cell-surface receptors. The type I receptor, an 80-kDa protein with a cytoplasmic domain of approximately 215 amino acids, mediates the biological effects of IL-1. The type II receptor, a 60-kDa protein with 29 cytoplasmic amino acids, binds IL-1 and thereby prevents it from binding to the type I receptor but does not deliver a biological signal. Thus, the type II receptor acts as a negative regulator of IL-1 actions. It can do so either as a membrane-bound molecule or subsequent to shedding from the cell surface to generate a so-called "soluble" receptor. Both the naturally produced soluble type II receptor and the recombinantly generated soluble type I receptor are effective inhibitors of IL-1 action. The soluble type I receptor has shown efficacy in some preclinical models of inflammatory diseases, as well as in an initial clinical trial in a setting of cutaneous allergy.

Animals↗
PubMed1994

The type II 'decoy' receptor: a novel regulatory pathway for interleukin 1.

The interleukin 1 (IL-1) system plays a central role in inflammation and immunity. Of the two receptors that bind IL-1, the type I receptor is known to mediate signaling activity, whereas the function of the type II receptor remains unknown. Here, Francesco Colotta and colleagues review the properties of these receptors and summarize evidence indicating that the type II receptor acts as a regulated decoy target for IL-1.

Animals↗
PubMed1994

Monoclonal antibody 1994-01 (also known as ALVA 42) reported to recognize type II IL-1 receptor is specific for HLA-DR alpha and beta chains.

Monoclonal antibody (MAb) 1994-01 has been reported to bind to the human type II Interleukin 1 (IL-1) receptor and in so doing block IL-1 binding in vitro and certain IL-1 mediated responses in vivo. While this antibody binds to a type II IL-1 receptor positive cell line, it can be shown that it does not bind to the type II IL-1 receptor. By direct expression cloning, we have identified two gene products, both of which are required for binding of this antibody. The two proteins are the alpha and beta subunits of the MHC class II antigen HLA-DR.

Antibodies, Monoclonal↗
PubMed1993

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.

Antibodies, Monoclonal↗
PubMed1993

Interleukin 1 signaling occurs exclusively via the type I receptor.

Two receptors for the proinflammatory cytokine interleukin 1 (IL-1) have been cloned and characterized biochemically. While it has been well established that the type I (80-kDa) IL-1 receptor can mediate responses to IL-1, the function of the type II (60-kDa) IL-1 receptor has been unknown. In this manuscript we describe experiments designed to ask whether the type II receptor is capable of delivering a biological signal. We have examined two types of experimental situation: responses to IL-1 in cells which express predominantly the type II receptor, and responses to IL-1 which have been suggested previously in the literature to be mediated by type II receptors. In both situations we find that the responses instead are mediated via type I receptors. A blocking antibody against the type II receptor never inhibits, and in fact sometimes enhances, the responses. We conclude that a very small number of type I receptors is sufficient to mediate all of the actions of IL-1 which we have examined here and that the function of the type II receptor may not be to transduce signals.

Animals↗
PubMed1993

Independent binding of interleukin-1 alpha and interleukin-1 beta to type I and type II interleukin-1 receptors.

Interleukin (IL)-1 refers to a group of three polypeptide hormones with a wide range of cellular targets. Two types of IL-1 receptor have been identified and characterized by cDNA cloning. Both human type I and type II IL-1 receptors contain extracellular domains of approximately 310 residues and a single membrane-spanning region. The type I receptor contains a cytoplasmic domain of 213 residues. The cytoplasmic region of the type II receptor is 29 residues in length. It has been found recently that a number of cells express both forms of receptor. By analogy with other cytokine receptor systems, the two IL-1 receptors might be expected to form a heterodimeric complex, the type II receptor being an alpha-chain-like structure, functioning only to bind ligand, and associating with the type I receptor (a beta-chain-like structure) which would transduce signals. In this report we show that this is not the case, but rather that IL-1, when complexed to type II receptor, cannot bind type I receptors, and vice versa. These data show that the complex patterns often observed for IL-1 binding to cells cannot be accounted for by the same type of mechanism that underlies the behavior of, for example, the IL-2 system.

Antibodies, Monoclonal↗