15-Lipoxygenase expression in smooth muscle cells from atherosclerotic rabbit aortas.
To determine the extent and origin of the stimulation of 15-lipoxygenase activity in atherosclerotic aortas, formation of hydroxy-derivatives from arachidonic acid was measured by HPLC-analysis and 15-lipoxygenase mRNA expression was investigated by RNA blot and in situ hybridization in atherosclerotic and normal rabbit aortic tissues. The synthesis of hydroxy-eicosatetraenoic acids (HETE) from exogenously added [14C]arachidonic acid was unchanged in atherosclerotic aortas in comparison with healthy aortas, but pretreatment with indomethacin demonstrated that 15-HETE production resulted essentially (75%) from cyclooxygenase activity in healthy aorta and from lipoxygenase activity in atherosclerotic aorta. The RNA blot and in situ hybridization with radiolabelled oligonucleotide probe demonstrated that 15-lipoxygenase mRNA was strictly localized in intimal thickening of atherosclerotic aortas. The immunostaining using anti-alpha smooth muscle actin, revealed that smooth muscle cell rich areas of the intimal thickening expressed 15-lipoxygenase mRNA. In addition, RNA blot hybridization indicated that cultured smooth muscle cells from atherosclerotic aortas expressed strongly 15-lipoxygenase mRNA. These results demonstrate that augmentation of 15-lipoxygenase activity in atherosclerotic aortas is correlated with 15-lipoxygenase mRNA expression in atherosclerotic plaque, and that intimal smooth muscle cells were involved, in addition to macrophages, in the expression of 15-lipoxygenase.
Hugou
I
I
INSERM U8, Pessac, France.
Blin
P
P
Henri
J
J
Daret
D
D
Larrue
J
J
D000818:Animals; D001011:Aorta / Q000201:enzymology* / Q000473:pathology; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D001161:Arteriosclerosis / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D015870:Gene Expression; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000201:enzymology* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits
D012333:RNA, Messenger; D001093:Arachidonate 15-Lipoxygenase