title: Hypochlorous acid-derived modification of phospholipids: characterization of aminophospholipids as regulatory molecules for lipid peroxidation.
abstract: Hypochlorous acid (HOCl), an inflammatory oxidant derived from neutrophil myeloperoxidase, can chlorinate cytosolic proteins and nuclear DNA bases of target cells by passing through the cell membrane. However, little is known about the consequences of HOCl-derived modification of cell membrane components, including phospholipids. In this study, we characterize the reaction of HOCl with phospholipid molecules and found that aminophospholipids are the key molecules that chemically regulate lipid peroxidation. Upon incubation with HOCl, the peroxidation of egg yolk phosphatidylcholine was significantly enhanced in the presence of phosphatidylethanolamine (PE). In contrast, the peroxidation was significantly inhibited in the presence of phosphatidylserine (PS). On the basis of mass spectrometric and electron paramagnetic resonance characterization, the initiator of the peroxidation was identified as the nitrogen-centered radical originating from PE-derived chloramines, especially N,N-dichlorinated PE, a major product in the HOCl-modified PE. Although PS was also chlorinated upon reaction with HOCl, the formed chloramine rapidly decomposed to phosphatidylglycolaldehyde, a novel class of lipid aldehyde. Formation of phosphatidylglycolaldehyde was also confirmed in the porcine brain PS and erythrocyte cell membrane ghost exposed to HOCl. These results provide a novel mechanism for the HOCl-induced oxidative damage and its endogenous protection in the cell membrane at the site of inflammation.
authors.affiliation: Department of Food Science, Graduate School of Nutrition and Biosciences, The University of Tokushima, Tokushima 770-8503, Japan. y-kawai@nutr.med.tokushima-u.ac.jp
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Kawai
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kiyokawa
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kimura
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kato
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D006997:Hypochlorous Acid / Q000737:chemistry*; D015227:Lipid Peroxidation; D013058:Mass Spectrometry; D010743:Phospholipids / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D010743:Phospholipids; D006997:Hypochlorous Acid