Journal of Lipid Research, Vol 37, 799-809, Copyright © 1996 by Lipid Research, Inc.
Role of oxidant injury on macrophage lipoprotein lipase (LPL) production and sensitivity to LPL
G Renier, AC Desfaits, A Lambert and R Mikhail
Department of Nutrition, Notre-Dame Hospital Research Center, University of Montreal, Quebec, Canada.
We investigated, in the present study, the role of reactive oxygen
intermediates (ROI) in the control of macrophage lipoprotein lipase (LPL)
secretion. Exposure of murine macrophages to increasing concentrations of
hydrogen peroxide (H2O2) resulted in enhanced basal LPL production and mRNA
levels. The increase of LPL production was reduced in the presence of
antioxidants. Oxidant stress also modulated the regulation of macrophage
LPL production by tumor necrosis factor alpha (TNF alpha). While
antioxidants accentuated the inhibition of LPL by TNF alpha, addition of
H2O2 significantly attenuated TNF alpha- induced LPL inhibition. As LPL has
been shown to induce macrophage TNF alpha release, the effect of reactive
oxygen species on LPL-induced TNF alpha production was also examined.
Simultaneous treatment of macrophages with LPL and H2O2 or pretreatment of
macrophages with H2O2 prior to LPL stimulation decreased the LPL-induced
TNF alpha release by macrophages to the same extent. Under these
experimental conditions, LPL binding to macrophages was markedly decreased.
These data indicate that ROI are effective enhancers of macrophage LPL
production and modulate macrophage response to LPL. These effects may
represent additional mechanisms through which oxidant stress may
participate to the development of atherosclerosis.