Extramural Research
Presentation Abstract
Grantee Research Project Results
Andre E. Nel
University of California–Los Angeles, Los Angeles, CA
NIEHS Grant Number: 1R01ES013432-01
Project Description:
The goal of this application is to engage a multidisciplinary team of
leading environmental, cardiovascular and proteomics researchers in the
study of the pro-oxidative and pro-inflammatory pathways by which ambient
particulate matter (PM) enhance atherogenesis in apolipoprotein (apoE)
and LDL receptor (LDL-R) deficient mice. The principal hypothesis is that
PM-induced oxidative stress synergizes with oxidized lipid components
to enhance inflammation and apoptosis in atherosclerotic lesions. There
are three specific aims. Aim 1 will determine whether ambient PM exposures
exacerbate atherosclerosis in these genetically susceptible strains. Animals
will be exposed to ambient ultrafine (aerodynamic diameter < 0.1 mu
m) and fine (< 2.5 mu m) particulates collected by particle concentrators
in the Los Angeles basin. The endpoints will be a quantitative assessment
of early and late atherosclerotic lesion development. These studies will
be supplemented by in vivo and in vitro studies looking at the pro-oxidative,
pro-inflammatory, and pro-apoptotic effects of concentrated ambient particulates
(CAPs) on vascular endothelial, smooth muscle and phagocytic cells. Aim
2 will determine the role of PM-induced oxidative stress in inflammation
and apoptosis. Aortic vascular tissue from CAPs exposed animals will be
examined for lipid peroxidation and for heme oxygenase 1 (HO-1) expression,
MAP kinase activation, and apoptosis. Blood will be used to study CAPs
effects on acute phase proteins, fibrinogen and oxidative modification
of protective HDL activity. Transgenic HO-1 promoter-luciferase mice will
be used for in vivo imaging of the kinetics and vascular sites of oxidative
stress generation. in vitro studies will include proteome analysis of
the oxidative stress response in endothelial cells. All oxidative stress
effects will be correlated with the PAH and quinone content of the CAPs,
as well as their in vitro redox cycle capacity, determined by the DTT
assay. Aim 3 will determine whether modified antioxidant defense mechanisms
affect the induction of atherosclerotic lesions by CAPs in apoE deficient
mice, which have been crossed with HO-1 transgenic as well as paraoxonase
knockout animals. The investigators will also determine whether a deficiency
of the Nrf-2 transcription factor, which regulates antioxidant enzyme
expression, will affect lesion development in apoE t/- animals. These
mice will be exposed to CAPs as discussed in Aims 1 and 2, and select
endpoints used to demonstrate the effect on atherosclerotic inflammation
and apoptosis.