The Formation of Some Antigenic Epitopes in Oxidized Human Low-Density Lipoprotein Is Inhibited by Nitric Oxide

Author： Seccia M. Perugini C. Bellomo G.

Publisher： Elsevier

ISSN： 0006-291X

Source： Biochemical and Biophysical Research Communications, Vol.232, Iss.3, 1997-03, pp. : 613-617

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

NO and NO-donors are able to inhibit the peroxidation of polyunsaturated fatty acids in human low-density lipoproteins (LDL) exposed to Cu ++ . Here we report that 1-hydroxy-2-oxo-3,3-bis(3-aminoethyl)-1-triazene (NOC-18), a compound which releases NO at low rate in aqueous solutions, powerfully inhibits the peroxidation of polyunsaturated fatty acids, tryptophan loss, the formation of fluorescent aldehydic adducts in apo B100 and the increase of electrophoretic mobility in isolated LDL undergoing oxidation. The inhibitory effect is not restricted to Cu ++ -induced peroxidation but is also detectable with other oxidizing conditions such as the free radical generator 2,2'-azobis-(2-amidino propane) hydrochloride (AAPH), the combination of horseradish peroxidase and H 2 O 2 (HRP), and peroxynitrite (ONOO - ). The recognition of Cu ++ -, AAPH-, and ONOO - -modified LDL by specific autoantibodies present in serum of atherosclerotic patients is almost completely inhibited when the oxidation procedure is performed in the presence of NOC-18. However, NOC-18 is completely ineffective in preventing the formation of recognizable antigens in HRP-modified LDL. These findings suggest that NO may efficiently prevent the formation of some, but not all, the antigenic epitopes recognized by human autoantibodies and thus likely formed during in vivo LDL oxidation.