Interleukin 1 beta and fever

Structural differences between the putative carbohydrate-recognition domains of human IL-1 alpha, IL-1 beta and IL-1 receptor antagonist obtained by in silico modeling

In a previous report (Cebo et al. J Biol Chem 276 (2001) 5685-5691), it was established that biologically active recombinant human IL-1alpha and IL-1beta had different carbohydrate-binding properties. IL-1alpha recognized a di-antennary N-glycan with two alpha2-3-linked sialic acid residues, whereas IL-1beta recognized the GM(4), a alpha2-3-linked sialylated glycosphingolipid. These different carbohydrate-binding properties of two interleukins binding to the same receptor (IL-1R) could explain why these molecules had different biological effects and cell specificities. Molecular modeling of the ligands and in silico docking experiments defined putative carbohydrate-recognition domains localized in the same area of the two molecules, a domain different from that defined as the type I IL-1R binding domain. The calculated pattern of hydrogen bonding and of van der Waals interactions fulfilled the essential features observed for calcium-independent lectins (mammalian, viral or bacterial). The analysis of the same domain of the third members of this family of molecules, the IL-1R-antagonist, indicated it did not fulfill the criteria for carbohydrate-recognition domains. It is proposed that its role as a pure antagonist is due to the absence of lectin activity and consequently explained its inability to associate IL-1R with other surface molecular complexes necessary for signaling.

Fever with acute arthritis in calcium pyrophosphate dihydrate deposition disease: a missed explanation for altered mental status in elderly patients?

Calcium pyrophosphate dihydrate (CPPD) deposition disease is a relatively common condition primarily affecting the elderly. Various clinical presentations ranging from an acute arthritis resembling gout (pseudogout) to fever of unknown origin have been reported. We describe four elderly patients with fever and altered mental status. Each patient underwent an extensive unrevealing work-up. An acute arthritis missed by the health-care team in their initial evaluation was later identified, leading to rheumatologic consultation and subsequent diagnosis of CPPD disease after joint aspiration and synovial fluid analysis. Defervescence and resolution of mental status changes occurred after improvement of the arthritis. Awareness that CPPD disease may present with systemic symptoms, including fever and altered mental status, may assure careful examination of joints and can prevent unnecessary testing and diagnostic delay.

Reactive oxygen intermediates in TNF signaling

Tumor necrosis factor (TNF) is arguably the most potent inducer of several intracellular signals, including apoptosis, cell differentiation, and gene transcription. It does so through the activation of caspases, specific kinases including mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), transcription factors Activated protein 1 (AP-1), and nuclear factor kappa-B (NF-kappaB). By activating these signals, TNF mediates pro-apoptotic and pro-survival mechanisms in the cell. It has also been suggested that TNF mediates its intracellular signaling by adjusting the redox potential of the cell, specifically through reactive oxygen intermediates (also known as reactive oxygen species). Here we review the evidence linking ROI to TNF-induced signaling and propose that ROI mediate both pro-apoptotic and pro-survival signals. How these antagonistic signals are balanced to maintain homeostasis is still not clear.

Recombinant human interleukins IL-1alpha, IL-1beta, IL-4, IL-6, and IL-7 show different and specific calcium-independent carbohydrate-binding properties

A method was developed for the determination of putative lectin activities of cytokines. It involved the immunoblotting measurement of the quantity of these cytokines unbound to a series of different immobilized glycoconjugates and displacement of the bound cytokines with oligosaccharides of known structures. This method allows demonstrating that the following interleukins specifically recognize different oligosaccharide structures in a calcium-independent mechanism: interleukin-1alpha binds to the biantennary disialylated N-glycan completed with two Neu5Acalpha2-3 residues; interleukin-1beta to a GM4 sialylated glycolipid Neu5Acalpha2-3Galbeta1-Cer having very long and unusual long-chain bases; interleukin-4 to the 1,7 intramolecular lactone of N-acetyl-neuraminic acid; interleukin-6 to compounds having N-linked and O-linked HNK-1-like epitopes; and interleukin-7 to the sialyl-Tn antigen. Because the glycan ligands are rare structures in human circulating cells, it is suggested that such activities could be essential for providing specific signaling systems to cells having both the receptors and the oligosaccharide ligands of the interleukin at their cell surface.

Effects of interleukin-10 on water intake, locomotory activity, and rectal temperature in rat treated with endotoxin

Intracerebroventricular (i.c.v.) interleukin-10 (25, 50, and 100 ng/rat) effects on water intake, exploratory behaviour, and rectal temperature were evaluated in rats treated intraperitoneally (i.p.) with lipopolysaccharide (0.32, 0.64, and 0.96 mg/kg). Endotoxin administration induced fever and inhibition of thirst in water-deprived rats, and a decrease in lococomotory activity in normohydrated and water-deprived animals. Our data show that interleukin-10 during lipopolysaccharide administration controlled fever, increases exploratory behaviour, but did not reverse lipopolysaccharide inhibition of thirst. These effects suggest that fever, depression in locomotory activity but not inhibition of thirst, induced by endotoxin are influenced by interleukin-10 levels.