Interleukin-4 and -13 Induce Upregulation of the Murine Macrophage 12/15-Lipoxygenase Activity: Evidence for the Involvement of Transcription Factor STAT6

Abstract

When human monocytes or alveolar macrophages are cultured in the presence of interleukin (IL)-4 or IL-13, the expression of the reticulocyte-type 15-lipoxygenase is induced. In mice a 15-lipoxygenase is not expressed, but a leukocyte-type 12-lipoxygenase is present in peritoneal macrophages. To investigate whether both lipoxygenase isoforms exhibit a similar regulatory response toward cytokine stimulation, we studied the regulation of the leukocyte-type 12-lipoxygenase of murine peritoneal macrophages by interleukins and found that the activity of this enzyme is upregulated in a dose-dependent manner when the cells were cultured in the presence of the IL-4 or IL-13 but not by IL-10. When peripheral murine monocytes that do not express the lipoxygenase were treated with IL-4 expression of 12/15-lipoxygenase mRNA was induced, suggesting pretranslational control mechanisms. In contrast, no upregulation of the lipoxygenase activity was observed when the macrophages were prepared from homozygous STAT6-deficient mice. Peritoneal macrophages of transgenic mice that systemically overexpress IL-4 exhibited a threefold to fourfold higher 12-lipoxygenase activity than cells prepared from control animals. A similar upregulation of 12-lipoxygenase activity was detected in heart, spleen, and lung of the transgenic animals. Moreover, a strong induction of the enzyme was observed in red cells during experimental anemia in mice. The data presented here indicate that (1) the 12-lipoxygenase activity of murine macrophages is upregulated in vitro and in vivo by IL-4 and/or IL-13, (2) this upregulation requires expression of the transcription factor STAT6, and (3) the constitutive expression of the enzyme appears to be STAT6 independent. The cytokine-dependent upregulation of the murine macrophage 12-lipoxygenase and its induction during experimental anemia suggests its close relatedness with the human reticulocyte-type 15-lipoxygenase despite their differences in the positional specificity of arachidonic acid oxygenation.

Regulation of cellular 15‐lipoxygenase activity on pretranslational, translational, and posttranslational levels

“…34, Supplement (1999) son for their unresponsiveness. Human alveolar macrophages (16) and murine peritoneal macrophages (7) constitutively express a 12/15-LOX. When cultured in the presence of IL-4, the level of expression is up-regulated by a factor of 2-5 (7,16).…”

“…Human alveolar macrophages (16) and murine peritoneal macrophages (7) constitutively express a 12/15-LOX. When cultured in the presence of IL-4, the level of expression is up-regulated by a factor of 2-5 (7,16). Although the mechanism of IL-4-induced up-regulation of 12/15-LOX synthesis is not completely understood, several constituents of the signal transduction cascade were identified.…”

“…Phospholipid hydroperoxide glutathione peroxidase (PH-GPx) was purified from pig hearts as described in Reference 5. Monocytes (human and murine) were prepared from peripheral blood by density gradient centrifugation and adherence to plastic dishes (6,7). Cells were cultured in vitro in the presence of recombinant interleukins for 3-5 d (5,8), and expression of the 15-LOX was tested by activity assays, immunoblotting, and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR).…”

Human 15‐lipoxygenase‐1 is a regulator of dendriticcell spreading and podosome formation

“…The expression of 15-LOX-1 is strictly regulated at the transcriptional, translational, and posttranslational levels (4)(5)(6)(7)(8). IL-4 and IL-13 have been shown to stimulate 15-LOX-1 expression (9) via the signal and activator of transcription 6/Janus kinase (STAT/JAK) signaling pathway in human peripheral monocytes (5,10).…”

“…AD is a T h 2-driven disease in which IL-4 and IL-13 are regarded to have an important pathologic function. These interleukins are potent stimulators of the expression of 15-LOX-1(10,24). Inhibition of 15-LOX-1 suppresses endocytosis and migration ability of DCs.…”