IL-4 enhances IL-3 and IL-8 gene expression in a human leukemic mast cell line.
We examined the capacity of interleukin (IL)-4 to induce or enhance the expression of certain cytokines in resting and activated cells of the HMC-1 human leukemic mast cell line. The HMC-1 mast cells were cultured with or without recombinant human IL-4 and then activated with the calcium ionophore ionomycin. Stimulation of non-IL-4-treated cells with ionomycin (10 microM) for periods of 30 min to 8 hr induced expression of mRNA encoding IL-3, IL-4 and IL-8 but was without effect on levels of mRNA for tumour necrosis factor (TNF)-alpha or beta-actin. Culture of the cells with IL-4 (100 ng/ml) for 24 hr led to a small increase in resting levels of mRNA for IL-3 and IL-8 but not for IL-4, TNF-alpha or beta-actin. More notably, the IL-4 treatment produced a pronounced elevation of mRNA for IL-3 and IL-8 when the cells were subsequently activated with ionomycin. The IL-4 treatment produced a negligible effect on IL-4 mRNA, and no effect on TNF-alpha or beta-actin mRNA levels in ionomycin-activated cells. Quantitation of cDNA by competitive polymerase chain reaction (PCR) revealed that the IL-4 treatment produced a sixfold increase in ionomycin-induced levels of cellular IL-3 mRNA, a fourfold increase in induced IL-8 mRNA and less than a twofold increase in induced IL-4 mRNA. The IL-4 treatment led to a 15- to 20-fold increase in ionomycin-induced secretion of IL-3 product and a doubling of induced IL-8 product. These effects of IL-4 were not associated with increased mast cell numbers. We conclude that IL-4 alone is a weak activator of IL-3 and IL-8 gene expression in mast cells, but is able to enhance activation signals in stimulated mast cells leading to transcription and secretion of these two cytokines.
Buckley
M G
MG
Department of Pharmacology and Therapeutics, University of Liverpool, UK.
Williams
C M
CM
Thompson
J
J
Pryor
P
P
Ray
K
K
Butterfield
J H
JH
Coleman
J W
JW
D001483:Base Sequence; D002455:Cell Division / Q000276:immunology; D015870:Gene Expression / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007377:Interleukin-3 / Q000096:biosynthesis* / Q000235:genetics; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D015759:Ionomycin / Q000494:pharmacology; D007942:Leukemia, Experimental / Q000276:immunology; D008407:Mast Cells / Q000276:immunology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
D007377:Interleukin-3; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D015759:Ionomycin