Regulation of 15-lipoxygenase expression in lung epithelial cells by interleukin-4.
We have studied the expression of the 15-lipoxygenase gene in various permanent mammalian cell lines in response to interleukins-4 and -13, and found that none of the cell lines tested expressed 5-, 12- or 15-lipoxygenase when cultured under standard conditions. However, when the lung carcinoma cell line A549 was maintained in the presence of either interleukin for 24 h or more, we observed a major induction of 15-lipoxygenase, as indicated by quantification of 15-lipoxygenase mRNA, by immunohistochemistry, by immunoblot analysis and by enzyme activity assays. This effect was 15-lipoxygenases-specific, since expression of 5- and 12-lipoxygenases remained undetectable. The time course of interleukin-4 treatment indicated maximal accumulation of both 15-lipoxygenase mRNA and functional protein after 48 h. Binding studies revealed that A549 cells express about 2100 high-affinity interleukin-4 binding sites per cell. The interleukin-4 mutant Y124D, which is capable of binding to the interleukin-4 receptor but is unable to trigger receptor activation, counteracted the effect of the wild-type cytokine. Other cell lines, including several epithelial cells and various monocytic cell lines expressing comparable numbers of interleukin-4 receptors, did not express 15-lipoxygenase when stimulated with interleukin-4. These data indicate that A549 cells selectively express 15-lipoxygenase when stimulated with interleukins-4 and -13. The activation of the interleukin-4/13 receptor(s) appears to be mandatory, but not sufficient, for 15-lipoxygenase gene expression.
Brinckmann
R
R
Institute of Biochemistry, University Clinics Charité, Humboldt University, Berlin, Federal Republic of Germany.
Topp
M S
MS
Zalán
I
I
Heydeck
D
D
Ludwig
P
P
Kühn
H
H
Berdel
W E
WE
Habenicht
J R
JR
D015703:Antigens, CD / Q000378:metabolism; D001093:Arachidonate 15-Lipoxygenase / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D004790:Enzyme Induction; D006801:Humans; D018793:Interleukin-13 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology*; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D018123:Receptors, Interleukin / Q000378:metabolism; D019948:Receptors, Interleukin-4; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D015703:Antigens, CD; D017931:DNA Primers; D018793:Interleukin-13; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D019948:Receptors, Interleukin-4; D015847:Interleukin-4; D001093:Arachidonate 15-Lipoxygenase