Malondialdehyde-Acetaldehyde Modified (MAA) Proteins Differentially Effect the Inflammatory Response in Macrophage, Endothelial Cells and Animal Models of Cardiovascular Disease.

Michael J Duryee,Logan M Duryee,Dahn L Clemens,Robert P Garvin,Patrick J Opperman,Daniel R Anderson,Geoffrey M Thiele

doi:10.3390/ijms222312948

Abstract

Chronic inflammation plays a critical role in the pathogenesis of atherosclerosis. Currently, the mechanism(s) by which inflammation contributes to this disease are not entirely understood. Inflammation is known to induce oxidative stress, which can lead to lipid peroxidation. Lipid peroxidation can result in the production of reactive by-products that can oxidatively modify macromolecules including DNA, proteins, and lipoproteins. A major reactive by-product of lipid peroxidation is malondialdehyde (MDA). MDA can subsequently break down to form acetaldehyde (AA). These two aldehydes can covalently interact with the epsilon (ε)-amino group of lysines within proteins and lipoproteins leading to the formation of extremely stable, highly immunogenic malondialdehyde/acetaldehyde adducts (MAA-adducts). The aim of this study was to investigate the inflammatory response to MAA-modified human serum albumin (HSA-MAA) and low-density lipoprotein (LDL-MAA). We found that animals injected with LDL-MAA generate antibodies specific to MAA-adducts. The level of anti-MAA antibodies were further increased in an animal model of atherosclerosis fed a Western diet. An animal model that combined both high fat diet and immunization of MAA-modified protein resulted in a dramatic increase in antibodies to MAA-adducts and vascular fat accumulation compared with controls. In vitro exposure of endothelial cells and macrophages to MAA-modified proteins resulted in increased fat accumulation as well as increased expression of adhesion molecules and pro-inflammatory cytokines. The expression of cytokines varied between the different cell lines and was unique to the individual modified proteins. The results of these studies demonstrate that different MAA-modified proteins elicit unique responses in different cell types. Additionally, the presence of MAA-modified proteins appears to modulate cellular metabolism leading to increased accumulation of triglycerides and further progression of the inflammatory response.

Highlights

Cardiovascular disease (CVD) is the leading cause of death worldwide [1]
To further our understanding of the role that MAA-adducts play in atherosclerosis, we investigated the effects of MAA-modified proteins in cultured endothelial cells and macrophages
Is expressed integrated density inflammation determined for the Atherosclerosis is aData disease driven as bythe chronic low-grade andentire aberrant slide

Summary

Introduction

Cardiovascular disease (CVD) is the leading cause of death worldwide [1]. The majority of these deaths are caused by coronary artery disease (CAD), which is a consequence of advanced atherosclerosis [1]. If the level of ROS exceeds the capacity of the cell to neutralize them, a state of oxidative stress develops. Oxidative stress can cause inflammation; likewise, inflammation can cause oxidative stress. These processes are intimately related and can establish a self-perpetuating cycle contributing to chronic inflammation [7,8]

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