The effects of mercuric chloride on growth, cytokine and MHC class II gene expression in a human leukemic mast cell line.
We have examined the effects of mercuric chloride (HgCl2) on growth and IL-4, IL-8, TNF-alpha and MHC class II gene expression in the HMC-1 human leukemic mast cell line. Proliferation, measured by [3H]thymidine incorporation or production of a formazan product (MTT assay), was substantially inhibited by HgCl2 at concentrations of 10(-6) M and above. Inspection of the DNA by agarose gel electrophoresis from HgCl2-treated cells revealed that it was intact, indicating inhibition of DNA synthesis, but not denaturation. HgCl2 inhibited expression of mRNA for IL-8, TNF-alpha and MHC class II at 4 x 10(-6) M and inhibited expression of IL-4 mRNA at 8 x 10(-6) M and above. At a concentration of 10(-5)M, HgCl2 almost completely blocked mRNA expression for IL-4, IL-8, TNF-alpha and MHC class II, but produced negligible inhibition of expression of mRNA encoding the housekeeping gene beta-actin, thus demonstrating selective toxicity for the cytokine and MHC class II genes studied. Pre-exposure of the cells to human recombinant IL-4 prior to treatment with HgCl2 had no effect on expression levels of any of the genes examined. The effects seen in this study are consistent with previous reports showing immunotoxic effects of HgCl2 on other cell types, therefore, the HMC-1 mast cell line may prove useful in further studies of mast cell cytokine gene expression and the mechanisms involved in cytokine gene toxicity.
Warbrick
E V
EV
Department of Pharmacology and Therapeutics, University of Liverpool, UK.
Thomas
A L
AL
Coleman
J W
JW
D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000096:biosynthesis / Q000737:chemistry / Q000187:drug effects; D004587:Electrophoresis, Agar Gel; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000235:genetics; D005802:Genes, MHC Class II / Q000235:genetics*; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D007946:Leukemia, Mast-Cell / Q000473:pathology; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008627:Mercuric Chloride / Q000633:toxicity*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
D016207:Cytokines; D017931:DNA Primers; D018076:DNA, Complementary; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D008627:Mercuric Chloride