Transplasma membrane redox activity of monocytes/macrophages

Abstract

Oxidation of low density lipoprotein in the arterial intima has been implicated in atherogenesis. Numerous studies have shown that various cells of the arterial wall, including macrophages, are able to oxidatively modify LDL in vitro. Although the exact mechanism of macrophage-mediated LDL oxidation in vitro remains unclear, it is generally accepted that it occurs via a transition metal-dependent process. Recently, it has been demonstrated that macrophages are able to reduce extracellular copper and iron, and the contribution to this reduction of a transplasma membrane electron transport (TPMET) system of the cells has been suggested.¹ In the present paper, we investigate the presence of a TPMET system in monocytes/ macrophages and ways to manipulate its activity. The establishment of ways to change the expression or activity of the TPMET system in these cells could provide convenient tool to further investigate the possible correlation between cellular transmembrane electron transport and the ability of cells to oxidise LDL.