Identification and characterization of a homologue of the pro-inflammatory cytokine Macrophage Migration Inhibitory Factor in the tick, Amblyomma americanum

2001 ◽  
Vol 10 (4) ◽  
pp. 323-331 ◽  
Author(s):  
D. C. Jaworski ◽  
A. Jasinskas ◽  
C. N. Metz ◽  
R. Bucala ◽  
A. G. Barbour
Keyword(s):  
Migration Inhibitory Factor ◽  
Macrophage Migration Inhibitory Factor ◽  
Inflammatory Cytokine ◽  
Amblyomma Americanum ◽  
Inhibitory Factor ◽  
Macrophage Migration ◽  
Identification And Characterization

Macrophage migration inhibitory factor antagonizes hydrocortisone-induced increases in cytosolic IκBα

2000 ◽  
Vol 279 (3) ◽  
pp. R1043-R1049 ◽  
Author(s):  
Jane M. Daun ◽  
Joseph G. Cannon
Keyword(s):  
Signal Transduction ◽  
Dna Binding ◽  
Migration Inhibitory Factor ◽  
Macrophage Migration Inhibitory Factor ◽  
Inflammatory Cytokine ◽  
Signal Transduction Pathway ◽  
Inhibitory Factor ◽  
Pituitary Cells ◽  
Macrophage Migration ◽  
Transduction Pathway

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine secreted by several cell types, including mononuclear and pituitary cells. It has also been shown to counteract cortisol-induced inhibition of inflammatory cytokine secretion. The purpose of this study was to determine whether MIF antagonized the effect of hydrocortisone on the NF-κB/IκB signal transduction pathway in lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells. Physiological doses of hydrocortisone (50–200 ng/ml) diminished both the LPS-stimulated decrease in cytosolic IκBα levels and the subsequent increase in nuclear NF-κB DNA binding. In the presence of both LPS and hydrocortisone, 1 ng/ml of MIF antagonized the effects of hydrocortisone, resulting in decreased cytosolic IκBα levels ( P < 0.05) and increased nuclear NF-κB DNA binding ( P < 0.05). In the absence of hydrocortisone, MIF had no effect on LPS-induced decreases in IκBα. In the absence of LPS, MIF inhibited hydrocortisone-induced increases in IκBα ( P = 0.03). Thus the mechanism by which MIF antagonizes the effect of hydrocortisone on the NF-kB/IκB signal transduction pathway is through inhibiting the ability of hydrocortisone to increase cytosolic IκBα.

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