Lipid Peroxidation Generates Body Odor Component trans-2-Nonenal Covalently Bound to Protein in Vivo

Abstract

trans-2-Nonenal is an unsaturated aldehyde with an unpleasant greasy and grassy odor endogenously generated during the peroxidation of polyunsaturated fatty acids. 2-Nonenal covalently modified human serum albumin through a reaction in which the aldehyde preferentially reacted with the lysine residues. Modified proteins were immunogenic, and a specific monoclonal antibody (mAb) 27Q4 that cross-reacted with the protein covalently modified with 2-nonenal was raised from mouse. To verify the presence of the protein-bound 2-nonenal in vivo, the mAb 27Q4 against the 2-nonenal-modified keyhole limpet hemocyanin was raised. It was found that a novel 2-nonenal-lysine adduct, cis-and trans-N ⑀ -3-[(hept-1-enyl)-4-hexylpyridinium]lysine (HHP-lysine), constitutes an epitope of the antibody. The immunoreactive materials with mAb 27Q4 were detected in the kidney of rats exposed to ferric nitrilotriacetate, an iron chelate that induces free radical-mediated oxidative tissue damage. Using high performance liquid chromatography with on-line electrospray ionization tandem mass spectrometry, we also established a highly sensitive method for detection of the cis-and trans-HHP-lysine and confirmed that the 2-nonenallysine adducts were indeed formed during the lipid peroxidation-mediated modification of protein in vitro and in vivo. Furthermore, we examined the involvement of the scavenger receptor lectin-like oxidized low density lipoprotein receptor-1 in the recognition of 2-nonenal-modified proteins and established that the receptor recognized the HHP-lysine adducts as a ligand.

4-Hydroperoxy-2-nonenal Is Not Just an Intermediate but a Reactive Molecule That Covalently Modifies Proteins to Generate Unique Intramolecular Oxidation Products

“…Zhu and Sayre (24) have previously identified a novel 4-ketoamide-type ONE-lysine adduct, N ⑀ -(4-oxononanoyl)lysine, that arises from a reversibly formed ONE-lysine Schiff base. We have also reported the formation of similar amide-type adducts upon reaction of the lysine derivative with n-alkanals in the presence of H 2 O 2 or alkyl hydroperoxides (25). Therefore, we hypothesized that HNE generated from HPNE might be involved in the formation of this product.…”

Chemistry and analysis of HNE and other prominent carbonyl-containing lipid oxidation compounds

“…These longer alkenals are less reactive than acrolein or crotonaldehyde, possibly owing to their lower solubility in aqueous solvents that favour nucleophilic attack; this may explain why they have received less attention as molecules capable of modifying biomolecules. However, using an immunoreactivity assay and high performance liquid chromatography with on-line electrospray ionization tandem mass spectrometry it has been demonstrated that 2-nonenal can cause considerable protein modification, formed preferentially on lysine residues [41].…”

“…Less reactive than other 2-alkenals, such as acrolein and crotonaldehyde, so has received relatively little attention as an [41,136] x Lipid oxidation and fragmentation generates a wide variety of reactive alkanals, alkenals, bis-aldehydes and D-chlorofatty aldehydes.…”

Lipid Peroxidation Modification of Protein Generates Nϵ-(4-Oxononanoyl)lysine as a Pro-inflammatory Ligand

“…4) prompted us to hypothesize that the ONL adduct could be recognized as a ligand by a membrane protein such as a scavenger receptor in the macrophages. Based on previous findings that the scavenger receptor LOX-1 might be involved in the processing of aldehyde-modified proteins (34,35) and that, among the aldehyde-treated proteins, the ONE-modified protein can be very efficiently incorporated into the LOX-1-overexpressing cells, 3 we sought to determine whether LOX-1 recognizes the ONL adduct. AcLDL was used as an alternative ligand to the OxLDL, which shows a comparable affinity to LOX-1 (36) to avoid ambiguous effects from variations in the extent of the oxidation of LDL (37,38).…”