Particulate Matter Promotes In Vitro Receptor‐Recognizable Low‐Density Lipoprotein Oxidation and Dysfunction of Lipid Receptors

Abstract

Particulate matter may promote cardiovascular disease, possibly as a consequence of its oxidative potential. Studies using susceptible animals indicate that particulate matter aggravates atherosclerosis by increasing lipid/macrophage content in plaques. Macrophage lipid uptake requires oxidized low‐density lipoprotein and scavenger receptors; same receptors are involved in particulate matter uptake. We studied in vitro particulate matter potential to oxidize low‐density lipoproteins and subsequent cell uptake through scavenger receptors. Particulate matter‐induced low‐density lipoproteins oxidation was evaluated by the thiobarbituric acid assay. Binding/internalization was tested in wild type and scavenger receptor–transfected Chinese hamster ovary cells, and in RAW264.7 cells using fluorescently labeled low‐density lipoproteins. Dose‐dependent binding/internalization only occurred in scavenger receptor–transfected Chinese hamster ovary cells and RAW264.7 cells. Competition binding/internalization using particles showed that particulate matter induced decreased binding (∼50%) and internalization (∼70%) of particle‐oxidized low‐density lipoproteins and native low‐density lipoproteins. Results indicate that particulate matter was capable of oxidizing low‐density lipoproteins, favoring macrophage internalization, and also altered scavenger and low‐density lipoproteins receptor function. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:69‐76, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21452Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96297/1/jbt21452.pd