| Project/Area Number |
10670134
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Pathological medical chemistry
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| Research Institution | Kanazawa University |
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Principal Investigator |
YOSHIMOTO Tanihiro School of Medicine, Kanazawa University Professor, 医学部, 教授 (60127876)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | 12-Lipoxygenase / Athelosclerosis / Low density lipoprotein (LDL) / Oxidized LDL / Scavenger receptor / Macrophage / 低比重リボタンパク質 / スカベンジャ-受容体 / アラキドン酸 / リポキシゲナーゼ / cDNAクローニング |
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| Research Abstract |
Lipoxygenase (LOX) incorporates a molecular oxygen into a specific carbon atom of unsaturated fatty acids. There are 5-, 8-, 12- and 15-LOXs in mammalian tissues according to the oxygenation site of arachidonic acid. Based upon the primary structures deduced from their cDNAs and enzymological properties, they are principally classified into 5-LOX and 12/15-LOX subfamilies. The 5-LOX catalyzes the first step in the generation of leukotrienes which have potent biological activities in the immediate hypersensitivity and allergy. There are number of isoforms of 12/15-LOXs : leukocyte, platelet and epidermis. Although the 12/15-LOXs have been shown to play roles in several systems such as atherosclerosis and neurotransmission, their pathophysiological functions are still subjects of investigation and discussion.
There are a body of circumstantial evidences for a role of LOX in oxidative modification of low density lipoprotein (LDL). The aim of this study was to investigate the role of intrac
… More
ellular 12-LOX in the oxidative modification of LDL that leads to foam cell formation. We overexpressed 12-lipoxygenases in a macrophage-like cell line J774A.1 which originally did not show the detectable enzyme activity. When the 12-lipoxygenase-expressing cells were incubated with LDL in Dulbecco's modified Eagle medium at 37 ℃ for 12 h, LDL oxidation as determined by thiobarbituric acid reactive substance was markedly increased over the mock-transfected cells. Oxygenated products in the modified LDL were examined by high performance liquid chromatography before and after alkaline hydrolysis. Most of the oxygenated derivatives were of an esterified form, and the major product was identified to be 13S-hydroxyoctadeca-9Z, 11E-dienoic acid. These results clearly demonstrated that esterified fatty acids in LDL were oxygenated by the 12-lipoxygenases expressed in the J774A.1 cells. Furthermore, the oxidized LDL generated by intracellular 12-lipoxygenases was recognized by a scavenger receptor as assessed by macrophage degradation assay. Less
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