Atherosclerosis 213 (2010) 449–457 Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis Two adjacent domains (141–150 and 151–160) of apoE covalently linked to a class A amphipathic helical peptide exhibit opposite atherogenic effects Gaurav Nayyar 1 , Shaila P. Handattu 1 , Candyce E. Monroe, Manjula Chaddha, Geeta Datta, Vinod K. Mishra, Tamara D. Keenum, Mayakonda N. Palgunachari, David W. Garber ∗ , G.M. Anantharamaiah Atherosclerosis Research Unit and the Department of Medicine, Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA article info Article history: Received 1 July 2010 Received in revised form 9 September 2010 Accepted 28 September 2010 Available online 27 October 2010 Keywords: Atherosclerosis Lipid oxidation Apolipoproteins Cholesterol Peptides abstract Objective: We recently described anti-atherogenic properties of the dual domain peptide Ac-hE18A-NH 2 derived by covalently linking the heparin binding domain 141–150 of apoE to 18A, a class A amphipathic helical peptide. In this paper we have compared the properties of Ac-hE18A-NH 2 with the non-heparin binding 151–160 region of apoE linked to 18A (Ac-nhE18A-NH 2 ). Methods and results: Both peptides were highly helical in solution and in association with lipids. Ac-hE18A- NH 2 and not Ac-nhE18A-NH 2 enhanced uptake of low density lipoprotein (LDL) in HepG2 cells. While Ac- hE18A-NH 2 retarded the electrophoretic mobility of LDL, Ac-nhE18A-NH 2 slightly enhanced mobility. Ac- hE18A-NH 2 reduced monocyte association with endothelial cells, while Ac-nhE18A-NH 2 increased it. Ac- hE18A-NH 2 also reduced lipid hydroperoxide content of LDL while Ac-nhE18A-NH 2 increased it. A single administration of Ac-hE18A-NH 2 (100 g/mouse) into apoE null mice dramatically reduced cholesterol (from 600 mg/dL to 180 mg/dL at 5 min and to 60 mg/dL at 5 h) while Ac-nhE18A-NH 2 had no effect. Administration (100 g/mouse/day, three days a week) into apoE null mice for six weeks showed Ac- hE18A-NH 2 group having a moderate aortic sinus lesion reduction compared with the control group (-15.1%), while the Ac-nhE18A-NH 2 administered group had increased lesion area (+33.0% vs controls and 36.1% vs Ac-hE18A-NH 2 ). Plasma from mice administered Ac-hE18A-NH 2 for six weeks showed a significant reduction in plasma cholesterol and triglyceride levels and increase in paraoxonase-1 (PON- 1) activity compared to controls, while Ac-nhE18A-NH 2 caused no change in plasma cholesterol and decreased PON-1 activity. Conclusion: It is proposed that Ac-hE18A-NH 2 reduced lesion progression in apoE null mice due to its anti-inflammatory and lipoprotein clearing properties, while Ac-nhE18A-NH 2 exhibited pro-atherogenic effects. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction The importance of apolipoprotein E (apoE) for clearing plasma cholesterol and inhibiting atherosclerosis has been demonstrated in an animal model by removal of the apoE gene in mice, which pro- duces atherosclerosis spontaneously with plasma containing high levels of very low density lipoprotein- (VLDL) like cholesterol rich particles [1,2] Over-expression of apoE in animals decreases cir- culating cholesterol levels [3]. Addition of apoE to VLDL enhances ∗ Corresponding author at: University of Alabama at Birmingham, 1808 7th Ave. S., BDB Room D-654, Birmingham, AL 35294, USA. Tel.: +1 205 934 1218; fax: +1 205 975 8079. E-mail address: Dgarber@uab.edu (D.W. Garber). 1 Gaurav Nayyar and Shaila P. Handattu contributed equally to this work. uptake and degradation of VLDL [4], which is known to carry more cholesterol per particle than LDL; both of these apoB-containing lipoproteins are atherogenic [5]. ApoE acts as a ligand for several receptors, including the LDL-receptor (LDLR) and the LDL receptor- related protein (LRP). Binding of apoE-containing lipoproteins to heparan sulfate proteoglycans (HSPG), and lipoprotein lipase medi- ates binding of apoE-containing lipoproteins, acting to clear LDL and VLDL in the space of Disse [6]. The region 141–160 of human apoE possesses a cationic putative receptor binding domain with the residue Cys at 158 of apoE2 replaced by Arg in isoform E3, the major allelic form that is present in normolipidemic individuals [7]. While the region 141–150 (LRKLRKRLLR) is highly cationic with six out of ten residues consisting of positively charged residues and the other residues being hydrophobic Leu, region 151–160 (DAD- DLQKRLA) is also rich in charged residues (5 out of 10) but possesses a 3:2 negative to positive charge ratio. 0021-9150/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2010.09.030