Oral administration of L-mR18L, a single domain cationic amphipathic helical peptide, inhibits lesion formation in ApoE null mice

Abstract

Supplementary key words atherosclerosis • metabolism • animals • lipids • cholesterolAs apolipoprotein (apo)A-I possesses tandem repeating class A amphipathic helical motifs, several investigators (including our own laboratory) have developed peptides that possess the class A amphipathic helical motif and have shown that, similar to apoA-I, several of these peptides not only interact with phospholipids to form nascent HDL-like peptide-lipid discoidal complexes but also possess both anti-infl ammatory and cellular cholesterol effl uxing properties ( 1-3 ). Several papers have been published using 4F and D-4F peptides to demonstrate that the peptides inhibit or slow down the onset of several infl ammatory diseases, including atherosclerosis (reviewed in Ref. 4 ). When 4F is synthesized from all D amino acids, the resulting D-4F is orally active and can be administered either in drinking water or mixed with food to inhibit infl ammatory processes ( 5 ). However, not all of the class A peptides are antiinfl ammatory ( 6, 7 ). It has been shown that the clustering of aromatic residues on the nonpolar face of a class A amphipathic helical motif favors its association with oxidized phospholipid ( 6-9 ).An ideal strategy for inhibiting atherosclerosis would not only decrease plasma cholesterol levels but also increase anti-infl ammatory properties. ApoE, the protein Abstract We have shown that Ac-hE18A-NH 2 , a dual-domain cationic apolipoprotein-mimetic peptide, reduces plasma cholesterol levels in dyslipidemic mice. Two singledomain cationic peptides based on the lytic class L peptide 18L were developed to test the hypothesis that a singledomain cationic amphipathic peptide can reduce atherosclerosis in apolipoprotein (apo)E null mice when orally administered. To incorporate anti-infl ammatory properties, aromatic residues were clustered in the nonpolar face similar to peptide 4F, resulting in modifi ed 18L (m18L). To reduce lytic properties, the Lys residues of 18L were replaced with Arg with the resulting peptide called modifi ed R18L (mR18L). Biophysical studies showed that mR18L had stronger interactions with lipids than did m18L. Peptide mR18L was also more effective than m18L in promoting LDL uptake by HepG2 cells. ApoE null mice received normal chow or chow containing m18L or mR18L for six weeks. A signifi cant reduction in plasma cholesterol and aortic sinus lesion area was seen only in the mR18L group. Plasma from mice administered mR18L, unlike those from the control and m18L groups, did not enhance monocyte adhesion to endothelial cells. Thus oral administration of mR18L reduces plasma cholesterol and lesion formation and inhibits monocyte adhesion. -Handattu, S. P., G. Datta, R. M. Epand, R.

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

“…Plasma from m18L-treated mice promoted the adhesion of monocytes to cultured bovine aortic endothelial cells. This response was not observed with plasma from mR18L-treated mice ( 144 ). These results suggested that mR18L possessed similar properties as Ac-hE18A-NH 2 , but possessed the advantage of oral bioavailability.…”

“…The incorporation of Arg residues in this peptide enhanced the uptake of LDL by HepG2 cells ( 144 ). Further, oral administration of mR18L, but not m18L, reduced plasma cholesterol and atherosclerotic lesion formation in apoE Ϫ / Ϫ mice ( 144 ). Plasma from m18L-treated mice promoted the adhesion of monocytes to cultured bovine aortic endothelial cells.…”

“…The peptide m18L was further modifi ed by substituting Lys residues with Arg to yield mR18L (Ac-GFRRFLGSWARIYRAFVG-NH 2 ) ( 144 ). The incorporation of Arg residues in this peptide enhanced the uptake of LDL by HepG2 cells ( 144 ). Further, oral administration of mR18L, but not m18L, reduced plasma cholesterol and atherosclerotic lesion formation in apoE Ϫ / Ϫ mice ( 144 ).…”

Sequence conservation of apolipoprotein A-I affords novel insights into HDL structure-function

“…2 ). One additional possible function of Arg in the right docking interface in general and in wp 7 in particular is based on recent research from this laboratory showing that Arg-containing amphipathic helical peptides sequester oxidized lipids more avidly than corresponding Lyscontaining peptides ( 80 ), suggesting that Arg may associate more avidly with oxidized phospholipids than Lys (see Fig. 12E for the proposed mechanism).…”

High-density lipoprotein mimetics: promises and challenges

“…The objective of such design was to create a mimetic capable of advancing its cargo along the pathway of lipoprotein metabolism. Anantharamaiah et al described conjugates of apoA-I mimetic peptide, active in promoting cholesterol efflux from cells, with a mimetic peptide reproducing the sequence of the receptor-binding domain of apoE, active in delivering cholesterol to the liver (Ac-hE-18A-NH 2 and L-mR18L) [34, 35]. Similar approach was used by Zhao et al , who described a peptide (EpK) containing lipid binding domain and LDL-receptor binding domain [36].…”