Cell-mediated LDL oxidation: The impact of transition metals and transferrin

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• 作者：Ann Van Campenhout ; Elke Heytens ; Christel Van Campenhout ; Albert R. Lagrou and Begoñ ; a Manuel-y-Keenoy
• 关键词：Macrophage ; Respiratory burst ; Low-density lipoproteins ; Lipid peroxidation ; Copper ; Iron ; Transferrin
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2005
• 出版时间：23 December 2005
• 年：2005
• 卷：338
• 期：3
• 页码：1617-1624
• 全文大小：600 K

文摘

Activated monocytes release oxygen radicals by respiratory burst and oxidative damage can be accelerated by transition metals. We investigated the cell-mediated and metal-catalysed in vitro oxidation of low-density lipoproteins (LDL), as well as the impact of the metal-binding protein transferrin (Tf). LDL oxidation was measured by monitoring the increase in fluorescence (350/440 nm excitation/emission). Maximal respiratory burst by U937 cells was achieved after 96 h differentiation with retinoic acid and dihydroxyvitamin D₃ followed by stimulation with opsonised zymosan. Addition of activated cells resulted in the LDL oxidation, even in the absence of transition metals. Moreover, activated cells greatly enhanced metal-catalysed oxidative modifications, especially in the presence of copper. By binding metals, Tf was able to strongly impair this process. In conclusion, by generating oxygen radicals, activated U937 cells were able to oxidise LDL. The oxidising process was most pronounced in the presence of copper and could be blocked by Tf.