A new HDL mimetic peptide that stimulates cellular cholesterol efflux with high efficiency greatly reduces atherosclerosis in mice

Abstract

Plasma HDLs are thought to protect against atherosclerosis via mechanisms related, in part, to reverse cholesterol transport (RCT) ( 1-3 ). This process involves removal of excess cholesterol from arterial foam-cells (i.e., cholesterol effl ux), followed by the transport of cholesterol to the liver for excretion in feces. Over-expression of apolipoprotein (apo) A-I, the major protein of HDL, in mice enhances RCT, inhibits atherosclerosis development, and stimulates regression of plaque lesions ( 4-8 ). Similar effects can be obtained upon infusion of apoA-I-phospholipid complexes in mice and humans, suggesting HDL may be useful therapeutically ( 9-11 ).Small peptides based on HDL apolipoproteins are being developed as alternatives to full-length recombinant proteins for therapeutic use (12)(13)(14). The mechanisms by which apolipoprotein mimetic peptides reduce atherosclerosis are not fully understood. The most widely studied 4F peptide reduces atherosclerosis in animal models via mechanisms related to binding of oxidized lipid ( 12,15 ). The latter anti-oxidant activity greatly exceeds that of apoA-I ( 16 ). The 18A/4F peptides can stimulate cholesterol effl ux from cells, albeit with far weaker activity Abstract Here, we report the creation of a single-helix peptide (ATI-5261) that stimulates cellular cholesterol effl ux with K m molar effi ciency approximating native apolipoproteins. Anti-atherosclerosis activity of ATI-5261 was evaluated in LDLR ؊ / ؊ and apolipoprotein (apo)E ؊ / ؊ mice ‫ف‬ 5-7 months of age, following 13-18 weeks on a high-fat Western diet (HFWD). Treatment of fat-fed LDLR؊ / ؊ mice with daily intraperitoneal injections of ATI-5261 (30 mg/kg) for 6 weeks reduced atherosclerosis by 30%, as judged by lesion area covering the aorta (7.9 ± 2 vs.11.3 ± 2.5% control, P = 0.011) and lipid-content of aortic sinus plaque (25 ± 5.8 vs. 33 ± 4.9% control, P = 0.014). In apoE ؊ / ؊ mice, the peptide administered 30 mg/kg ip on alternate days for 6 weeks reduced atherosclerosis by ‫ف‬ 45% (lesion area = 15 ± 7 vs. 25 ± 8% control, P = 0.00016; plaque lipid-content = 20 ± 6 vs. 32 ± 8% control, P < 0.0001). Similar reductions in atherosclerosis were achieved using ATI-5261:POPC complexes. Single intraperitoneal injection of ATI-5261 increased reverse cholesterol transport from macrophage foam-cells to feces over 24-48 h. In summary, relatively short-term treatment of mice with the potent cholesterol effl ux peptide ATI-5261 reduced substantial atherosclerosis. This was achieved using an L-amino acid peptide, in the presence of severe hypercholesterolemia/ HFWD, and did not require daily injections or formulation with phospholipids when administered via intraperitoneal

Anti-inflammatory and cholesterol-reducing properties of apolipoprotein mimetics: a review

“…Biophysical studies showed that the peptide possessed a high aqueous solubility that dissociated to trimers, dimers, and monomers upon dilution ( 127 ). The effi ciency of ATI-5261 in mediating macrophage cholesterol effl ux was similar to that of full-length apoA-I and apoE ( 65 ). Further, cholesterol effl ux was increased by treatment of cells with peptide in either a lipid-free form or as a phospholipid complex ( 65 ).…”

“…A 10 amino acid peptide from the apoJ sequence was also shown to increase plasma cholesterol effl ux capacity in apoE Ϫ / Ϫ mice and improve HDL anti-infl ammatory properties ( 61 ). Other groups set out to improve the properties of existing peptide sequences ( 62,63 ) or to design entirely new sequences (64)(65)(66)(67).…”

“…C-terminal residues 238-270 were structurally modifi ed to yield the single helix model peptide ATI-5261 ( 65 ). Biophysical studies showed that the peptide possessed a high aqueous solubility that dissociated to trimers, dimers, and monomers upon dilution ( 127 ).…”

Transintestinal transport of the anti-inflammatory drug 4F and the modulation of transintestinal cholesterol efflux

“…4F can bind oxidized lipids with much higher affinity than apoAI (50), while its capacity to stimulate cholesterol efflux from macrophages is lower than apoAI on a per molar basis (80,81). Facts like these have led some to argue that the cholesterol efflux capacity of 4F is of secondary importance at best compared with its antioxidative capacity, as regards its effects on atherosclerosis (82). However, if 4F affects cholesterol efflux and macrophage RCT in vivo at the level of TICE rather than at the level of cholesterol efflux from macrophages themselves, as is suggested by results reported in Fig.…”

Intestine may be a major site of action for the apoA-I mimetic peptide 4F whether administered subcutaneously or orally

“…Future studies will be needed to determine if the fi ndings described here regarding the importance of dose independent of plasma peptide levels and the likely role of the intestine will also apply to other apoA-I mimetic peptides, particularly those which are thought to be more active on reverse cholesterol transport (19)(20)(21).…”