Acrolein Impairs ATP Binding Cassette Transporter A1-dependent Cholesterol Export from Cells through Site-specific Modification of Apolipoprotein A-I

Abstract

Acrolein is a highly reactive ␣,␤-unsaturated aldehyde, but the factors that control its reactions with nucleophilic groups on proteins remain poorly understood. Lipid peroxidation and threonine oxidation by myeloperoxidase are potential sources of acrolein during inflammation. Because both pathways are implicated in atherogenesis and high density lipoprotein (HDL) is anti-atherogenic, we investigated the possibility that acrolein might target the major protein of HDL, apolipoprotein A-I (apoA-I), for modification. Tandem mass spectrometric analysis demonstrated that lysine 226, located near the center of helix 10 in apoA-I, was the major site modified by acrolein. Importantly, this region plays a critical role in the cellular interactions and ability of apoA-I to transport lipid. Indeed, we found that conversion of Lys-226 to N ⑀ -(3-methylpyridinium)lysine by acrolein associated quantitatively with decreased cholesterol efflux from cells via the ATP-binding cassette transporter A1 pathway. In the crystal structure of truncated apoA-I, Glu-234 lies adjacent to Lys-226, suggesting that negatively charged residues might direct the modification of specific lysine residues in proteins. Finally, immunohistochemical studies with a monoclonal antibody revealed co-localization of apoA-I with acrolein adducts in human atherosclerotic lesions. Our observations suggest that acrolein might interfere with normal reverse cholesterol transport by HDL by modifying specific sites in apoA-I. Thus, acrolein might contribute to atherogenesis by impairing cholesterol removal from the artery wall.Chemical damage to key proteins may contribute to the pathogenesis of many disorders, including diabetes, Alzheimer disease, and ischemiareperfusion injury and perhaps to the aging process itself (1). Reactive aldehydes are an important class of agents that covalently modify proteins, and a variety of enzymatic and nonenzymatic mechanisms generate them in the body (2). Acrolein is the most reactive ␣,␤-unsaturated aldehyde, and it rapidly modifies biological nucleophiles (3). This potent electrophile may be produced in the body through lipid peroxidation or peroxidation of threonine by myeloperoxidase, and high levels are found in cigarette smoke (4 -6). Lipid peroxidation, myeloperoxidase, renal disease, and cigarette smoking all strongly associate with an increased risk of vascular disease (2,7,8). Moreover, epitopes recognized by a monoclonal antibody specific for lysine adducts of acrolein have been detected in macrophages of atherosclerotic lesions (4), raising the possibility that acrolein is one important agent for damaging proteins in the artery wall. Acrolein may also be a uremic toxin, and carbonyl stress appears to increase in patients with chronic renal failure (9).Like other ␣,␤-unsaturated aldehydes, acrolein selectively reacts with the sulfhydryl group of cysteine, the imidazole group of histidine, and the ⑀-amino group of lysine (10 -12). Indirect evidence suggests that it might also modify arginine (13). In vitro studies ha...

Modification by Acrolein, a Component of Tobacco Smoke and Age-Related Oxidative Stress, Mediates Functional Impairment of Human Apolipoprotein E

“…Thus, it may be anticipated that there will be more lipid-free apoE in the plasma under conditions of oxidative stress, such as aging and smoking. In a recent study, it was suggested that endogenously generated acrolein may form covalent adducts with apoAI, a related exchangeable apolipoprotein that is considered anti-atherogenic (49,50). It was noted that acrolein modification correlated with a decreased cellular cholesterol efflux capability of apoAI mediated by the ATP-binding cassette transporter AI.…”

“…In other studies, we noted that acrolein modified apoE3-NT without the His-tag as well (data not shown). Since N ε -(3-methylpyridinium)lysine appears to be the major epitope for mAb5F6 in other acrolein-modified proteins (48)(49)(50), it is likely that this may be the case for acrolein-modified apoE as well. The formation of other types of acrolein-lysine-adducts of apoE such as N ε -(3-formy-3,4-dehydropiperidino)lysine, for which mAb5F6 also shows some immunoreactivity (48), cannot be excluded at this point.…”

Characterization of Acrolein-Glycerophosphoethanolamine Lipid Adducts Using Electrospray Mass Spectrometry

“…The acroleinlysine adducts identified include N ε -(3-formyl-3,4-dehydropiperidine)lysine (9) and N ε -(3-methylpyridinium)lysine (10). Using a specific antibody, acrolein-protein adducts have been detected immunohistochemically in Alzheimer's diseased brains (12), in the spinal cord after traumatic injury (43), and in atherosclerotic lesions (44). While covalent modifications of DNA and proteins with acrolein have been the focus of many investigations, the reaction of acrolein with glycerophosphoethanolamine lipids, another major cellular nucleophile, has not been reported.…”

Interplay Between Oxidative and Carbonyl Stresses: Molecular Mechanisms, Biological Effects and Therapeutic Strategies of Protection

“…It is well documented that LPO-derived RCS reacting with proteins produce such ALEs as MDA-Lys, HNE-Lys, propanal-His, propenal-Lys, and S-carboxymethyl-cysteine, as well as such cross-link as MDA-lysine dimmer, among many others ( Figure 11) (Uchida et al, 1997;Shao et al, 2005;Pamplona, 2008 and. LPO end products can also interact with amino groups of deoxyguanosine, deoxycytosine, guanosine to form various alkylated products (Pamplona, 2008).…”