Charles A. Dinarello

Bio: Charles A. Dinarello is an academic researcher from University of Colorado Denver. The author has contributed to research in topics: Interleukin & Cytokine. The author has an hindex of 190, co-authored 1058 publications receiving 139668 citations. Previous affiliations of Charles A. Dinarello include University of Guadalajara & Pennsylvania State University.

The combination of soluble IL-18Ralpha and IL-18Rbeta chains inhibits IL-18-induced IFN-gamma.

Abstract: Although the beta chain of interleukin-18 receptor (IL-18Rbeta) is required for signaling, the soluble (extracellular) form does not bind IL-18, and its role in inhibiting IL-18 is unclear. In the present study, both the soluble human IL-18 ligand binding alpha chain (sIL-18Ralpha) and the sIL-18Rbeta chain were investigated for inhibition of IL-18-induced interferon-gamma (IFN-gamma) production in human peripheral blood mononuclear cells (PBMC), whole blood, and KG-1 macrophage and natural killer (NK) cell lines. Neutralization of IL-18 by soluble receptors was compared with that of the IL-18 binding protein (IL-18BP). An equimolar concentration IL-18BP inhibited 90% of IL-18 activity, whereas a 4-fold molar excess of sIL-18Ralpha had no effect. A dimeric construct of sIL-18Ralpha linked to the Fc domain of IgG1 (sIL-18Ralpha:Fc) increased IL-18 activity 2.5-fold. In PBMC stimulated with lypopolysaccharide (LPS) or in whole blood stimulated with Staphylococcus epidermidis, 3 nM IL-18BP reduced IFN-gamma by 80%, whereas IL-18Ralpha:Fc had no effect. A construct of the sIL-18Rbeta linked to Fc (sIL-18Rbeta:Fc) did not affect IL-18-induced IFN-gamma even at 80-fold molar excess of IL-18. However, the combination of both soluble receptors reduced IFN-gamma by 80%. In KG-1 cells, a 50% reduction in IL-18 activity was observed using an 80-fold molar excess of sIL-18Ralpha:Fc but only in the presence of sIL-18Rbeta:Fc. Similarly, a 50% reduction was observed using sIL-18Rbeta:Fc in the presence of a molar excess of sIL-18Ralpha:Fc. Similar inhibition was observed in NK cells. These studies reveal that the combination of the ligand-binding and the nonligand-binding extracellular domains of IL-18R is needed to inhibit IL-18, whereas IL-18BP neutralizes at equimolar concentration.

A promoter polymorphism in human interleukin-32 modulates its expression and influences the risk and the outcome of epithelial cell–derived thyroid carcinoma

Abstract: Interleukin (IL)-32 is an intracellular proinflammatory mediator that strongly modulates the inflammatory reaction. Recent studies have suggested the involvement of IL-32 in the pathogenesis of malignancies. We aimed to assess whether a known germ-line polymorphism in the IL32 promoter modulates IL-32 expression, and whether it influences susceptibility and/or outcome of epithelial cell-derived thyroid carcinoma (TC). In this study, IL32 genotype was assessed in 139 TC patients and 138 healthy controls and was correlated with TC susceptibility and clinical outcome. Furthermore, IL-32 messenger RNA expression and protein were assessed in TC tissues and functional consequences of genetic variants of IL32 were studied in a model of human primary immune cells. Results demonstrate substantial IL-32 expression in TC tumor tissue. Lipopolysaccharide (LPS) stimulation of primary immune cells revealed 2-fold higher expression of IL-32γ, but not IL-32β, in cells homozygous for the ancient T allele. Furthermore, production of LPS-induced cytokines was increased in cells bearing this T allele. Genetic analysis revealed that the ancient T allele was overrepresented in TC patients with odds ratio (95% confidence interval) = 1.71 (1.06-2.75). In addition, the cumulative radioactive iodine (RAI) dose received after total thyroidectomy was significantly higher in TC patients bearing the ancient T allele. In conclusion, individuals bearing genetic variants of IL32 that lead to an increased IL-32γ gene expression and higher production of proinflammatory cytokines have higher risk for developing epithelial cell-derived TC. Subsequently, they require higher dosages of RAI to achieve successful tumor remission. These data suggest an important role of IL-32 in the pathogenesis of TC.

Efficacy of canakinumab as first-line biologic agent in adult-onset Still’s disease

Abstract: Adult-onset Still’s disease (AOSD) is a rare condition characterized by fever, arthritis, skin rash, and multi-organ inflammation. The pathogenesis is mediated by the pro-inflammatory cytokine interleukin (IL)-1β, as confirmed by the clinical efficacy of selective blockade. Anakinra, a recombinant inhibitor of the IL-1β receptor, currently represents the cornerstone of biologic therapy [1]. More recently, a monoclonal antibody blocking IL-1β, canakinumab, entered the clinical arena and became available for the treatment of AOSD. The efficacy of canakinumab in AOSD is being evaluated in a clinical trial (NCT022042939). At present, evidence from several case reports or series suggest good efficacy in AOSD (reviewed in [2, 3]): of note, in all published cases, canakinumab was used following failure of one or more biologics, including anakinra. Here, we report the efficacy of canakinumab as a first-line biologic agent in AOSD. Four patients with severe DMARD-refractory AOSD received canakinumab (4mg/ kg/4 weeks) following failure of conventional treatment with corticosteroids and methotrexate. Patient characteristics and response to therapy are shown in Table 1. In all patients, treatment with canakinumab led to striking clinical responses, within days of initiation. Fever and skin rash disappeared first, followed by progressive improvement in arthritis. If present, inflammatory organ involvement also responded to treatment, as confirmed by resolution of pericardial inflammation and hepatosplenomegaly in two and one patients, respectively. Marked reductions in CRP, ESR, and serum ferritin mirrored the efficacy on clinical manifestations. Reduced disease severity allowed for robust tapering of corticosteroid therapy, which was discontinued in two patients and substantially reduced in two patients (Table 1). Biologic therapy with IL-1 inhibitors should be instituted earlier in AOSD course for more favorable outcomes [2]. Both IL-1 blocking agents anakinra and canakinumab received EMA approval for the treatment of AOSD. Although anakinra and canakinumab block the same target, they have different mechanisms of action. Anakinra, a recombinant inhibitor of the IL-1 receptor, requires daily injections due to a short half-life of 6 h. Canakinumab, a fully human monoclonal antibody selectively blocking IL-1β, has a longer half-life and is administered monthly [4]. In this study, first-line biologic therapy of AOSD with canakinumab resulted in rapid and marked efficacy, ultimately leading to full clinical remissions in all patients and allowing for robust steroid-sparing effects. Canakinumab in AOSD is often used as a last line of treatment following failure of multiple other agents, including anakinra [2]. Early treatment is nevertheless advisable and may reduce chances of chronic disease and permanent damage [2, 5].

Review of recent developments in the molecular characterization of recombinant alfa interferons on the 40th anniversary of the discovery of interferon.

Abstract: Recombinant alfa interferons (IFN-αs) are approved worldwide for the treatment of a variety of cancers and diseases of virologic origin. A series of recent advances in the molecular characterization of recombinant IFN-αs have allowed the determination of the three-dimensional IFN-α2b structure by high-resolution x-ray crystallography. We review here recent developments in our understanding of the molecular and physicochemical properties of recombinant IFN-α, including our current state of knowledge of the IFN-α gene family and the multiple species of human leukocyte IFN. Based on the reported three-dimensional structure oflFN-α2b, we propose a molecular model for the IFN-α2b receptor complex and predict models for the naturally occurring subtypes IFN-α1 and lFN-α8, as well as the synthetic, non–naturally occurring consensus IFN. Such models provide molecular insights into the mechanism of action of IFN-α.

Identification of a Critical Ig-Like Domain in IL-18 Receptor α and Characterization of a Functional IL-18 Receptor Complex

Abstract: Steady state mRNA levels in various human tissues reveal that the proinflammatory cytokine IL-18 is constitutively and ubiquitously expressed. However, limited IL-18R alpha-chain (IL-18Ralpha) expression in tissues may restrict ligand-acting sites and contribute to a specific response for IL-18. To study the IL-18R complex, [(125)I]IL-18 was studied for binding to the cell surface receptors of IL-18-responsive NK and macrophagic KG-1 cells. After cross-linking, [(125)I]IL-18 formed three IL-18R complexes with sizes of approximately 93, 160, and 220 kDa. In KG-1 cells, Scatchard analysis revealed the presence of 135 binding sites/cell, with an apparent dissociation constant (K(d)) of 250 pM; in NK cells, there were 350 binding sites per cell with an apparent K(d) of 146 pM. Each domain of extracellular IL-18Ralpha was cloned and individually expressed in Escherichia coli. An mAb specifically recognized the membrane-proximal third domain; this mAb blocked IL-18-induced IFN-gamma production in NK cells. Furthermore, deletion of the membrane-proximal third domain of IL-18Ralpha prevented the formation of IL-18R ternary complex with IL-18R beta-chain. The present studies demonstrate that the biologically active IL-18R complex requires the membrane-proximal third Ig-like domain in IL-18Ralpha for the formation of IL-18R ternary complex as well as for signal transduction involved in IL-18-induced IFN-gamma in NK cells.

The pathogenesis of atherosclerosis: a perspective for the 1990s

Abstract: Atherosclerosis, the principal cause of heart attack, stroke and gangrene of the extremities, is responsible for 50% of all mortality in the USA, Europe and Japan. The lesions result from an excessive, inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall. A large number of growth factors, cytokines and vasoregulatory molecules participate in this process. Our ability to control the expression of genes encoding these molecules and to target specific cell types provides opportunities to develop new diagnostic and therapeutic agents to induce the regression of the lesions and, possibly, to prevent their formation.

Cancer-related inflammation.

Abstract: The mediators and cellular effectors of inflammation are important constituents of the local environment of tumours. In some types of cancer, inflammatory conditions are present before a malignant change occurs. Conversely, in other types of cancer, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumours. Regardless of its origin, 'smouldering' inflammation in the tumour microenvironment has many tumour-promoting effects. It aids in the proliferation and survival of malignant cells, promotes angiogenesis and metastasis, subverts adaptive immune responses, and alters responses to hormones and chemotherapeutic agents. The molecular pathways of this cancer-related inflammation are now being unravelled, resulting in the identification of new target molecules that could lead to improved diagnosis and treatment.

Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012.

Abstract: Objective:To provide an update to the “Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock,” last published in 2008.Design:A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at ke

Inflammation in atherosclerosis

Abstract: Abundant data link hypercholesterolaemia to atherogenesis. However, only recently have we appreciated that inflammatory mechanisms couple dyslipidaemia to atheroma formation. Leukocyte recruitment and expression of pro-inflammatory cytokines characterize early atherogenesis, and malfunction of inflammatory mediators mutes atheroma formation in mice. Moreover, inflammatory pathways promote thrombosis, a late and dreaded complication of atherosclerosis responsible for myocardial infarctions and most strokes. The new appreciation of the role of inflammation in atherosclerosis provides a mechanistic framework for understanding the clinical benefits of lipid-lowering therapies. Identifying the triggers for inflammation and unravelling the details of inflammatory pathways may eventually furnish new therapeutic targets.