1-palmitoyl-2-oleoylphosphatidylcholine and Atherosclerosis

Epidemiological results revealed that there is an inverse correlation between high-density lipoprotein (HDL) cholesterol levels and risks of atherosclerotic cardiovascular disease (ASCVD). Mounting evidence supports that HDLs are atheroprotective, therefore, many therapeutic approaches have been developed to increase HDL cholesterol (HDL-C) levels. Nevertheless, HDL-raising therapies, such as cholesteryl ester transfer protein (CETP) inhibitors, failed to ameliorate cardiovascular outcomes in clinical trials, thereby casting doubt on the treatment of cardiovascular disease (CVD) by increasing HDL-C levels. Therefore, HDL-targeted interventional studies were shifted to increasing the number of HDL particles capable of promoting ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux. One such approach was the development of reconstituted HDL (rHDL) particles that promote ABCA1-mediated cholesterol efflux from lipid-enriched macrophages. Here, we explore the manipulation of rHDL nanoparticles as a strategy for the treatment of CVD. In addition, we discuss technological capabilities and the challenge of relating preclinical in vivo mice research to clinical studies. Finally, by drawing lessons from developing rHDL nanoparticles, we also incorporate the viabilities and advantages of the development of a molecular imaging probe with HDL nanoparticles when applied to ASCVD, as well as gaps in technology and knowledge required for putting the HDL-targeted therapeutics into full gear.

Topics: Animals; Apolipoprotein A-I; Atherosclerosis; ATP Binding Cassette Transporter 1; Biomimetics; Drug Discovery; Humans; Lipoproteins, HDL; Macrophages; Mice; Molecular Imaging; Nanoparticles; Phosphatidylcholines

The goal of this study was to understand how the reconstituted HDL (rHDL) phospholipid (PL) composition affects its cholesterol efflux and anti-inflammatory properties. An ApoA-I mimetic peptide, 5A, was combined with either SM or POPC. Both lipid formulations exhibited similar in vitro cholesterol efflux by ABCA1, but 5A-SM exhibited higher ABCG1- and SR-BI-mediated efflux relative to 5A-POPC (P < 0.05). Injection of both rHDLs in rats resulted in mobilization of plasma cholesterol, although the relative potency was 3-fold higher for the same doses of 5A-SM than for 5A-POPC. Formation of preβ HDL was observed following incubation of rHDLs with both human and rat plasma in vitro, with 5A-SM inducing a higher extent of preβ formation relative to 5A-POPC. Both rHDLs exhibited anti-inflammatory properties, but 5A-SM showed higher inhibition of TNF-α, IL-6, and IL-1β release than did 5A-POPC (P < 0.05). Both 5A-SM and 5A-POPC showed reduction in total plaque area in ApoE(-/-) mice, but only 5A-SM showed a statistically significant reduction over placebo control and baseline (P < 0.01). The type of PL used to reconstitute peptide has significant influence on rHDL's anti-inflammatory and anti-atherosclerosis properties.

Topics: Animals; Apolipoprotein A-I; Atherosclerosis; Cholesterol; Humans; Inflammation; Lipoproteins, HDL; Mice; Peptides; Phosphatidylcholines; Phospholipids; Rats; Sphingomyelins

To test the hypothesis that sidedness of interfacial arginine (Arg) in apoA-I mimetic peptides, similar to that observed in apoA-I (Bashtovyy, D. et al. 2011. Sequence conservation of apolipoprotein A-I affords novel insights into HDL structure-function. J. Lipid Res. 52: 435-450.), may be important for biological activity, we compared properties of 4F and analogs, [K⁴,¹⁵>R]4F and [K⁹,¹³>R]4F, with Lys>Arg substitutions on the right and left side, respectively, of the 4F amphipathic helix. Intraperitoneal administration of these peptides into female apoE null mice (n = 13 in each group) reduced en face lesions significantly compared with controls; 4F and [K⁴,¹⁵>R]4F were equally effective whereas [K⁹,¹³>R]4F was less effective. Turnover experiments indicated that [K⁴,¹⁵>R]4F reached the highest, whereas [K⁹,¹³>R]4F had the lowest, plasma peak levels with a similar half life as the [K⁴,¹⁵>R]4F analog. The half life of 4F was two times longer than the other two peptides. The order in their abilities to associate with HDL in human plasma, generation of apoA-I particles with pre-β mobility from isolated HDL, lipid associating ability, and sensitivity of lipid complexes to trypsin digestion was: 4F>[K⁴,¹⁵,>R]4F>[K⁹,¹³>R]4F. These studies support our hypothesis that the sidedness of interfacial Arg residues in the polar face of apoA-I mimetics results in differential biological properties.

Topics: Animals; Apolipoprotein A-I; Arginine; Aryldialkylphosphatase; Atherosclerosis; Chemical Phenomena; Cholesterol; Female; Gene Deletion; Guanidine; Humans; Lipoproteins, HDL; Mice; Oxidation-Reduction; Peptidomimetics; Phosphatidylcholines; Protein Structure, Secondary; Protein Unfolding; Reactive Oxygen Species; Unilamellar Liposomes

Reconstituted high-density lipoprotein (rHDL) has been shown to produce a rapid regression of atherosclerosis in animal models and humans. Sphingosine-1-phosphate (S1P), which is a bioactive lipid in HDL, plays a role in mitogenesis, endothelial cell motility, and cell survival, as well as organization and differentiation into a vessel. In this study, we examined the direct role of a newly developed rHDL, [POPC(1-palmitoyl-2-oleoyl phosphatidylcholine)/S1P/apolipoproteinA-I(A-I)]rHDL containing S1P in tube formation in endothelial cells (ECs) as well as cholesterol efflux in macrophage. The effect of (POPC/S1P/A-I)rHDL on cholesterol efflux in macrophage was similar to that of conventional rHDL, (POPC/A-I)rHDL. In addition, (POPC/S1P/A-I)rHDL induced EC proliferation through the activation of phospho-Akt and phospho-extracellular-signal-regulated kinases (p-ERK) 1/2 and EC tube formation, and this effect was blocked by inhibitors of Akt, ERK and endothelial nitric-oxide synthase (eNOS). In addition, (POPC/S1P/A-I)rHDL-induced p-ERK1/2 activation and EC tube formation can be mainly attributed to S1P-stimulated signaling through S1P2 and S1P3 as determined by an anti-sense strategy. In conclusion, (POPC/S1P/A-I)rHDL induces cholesterol efflux independently of S1P but has additional S1P-mediated effects on EC tube formation mediated by Akt/ERK/NO through S1P2 and S1P3. In the future, these new discs may be useful for the treatment of atherosclerotic and ischemic cardiovascular disease, such as acute coronary syndrome and atherosclerosis obliterans.

Topics: Animals; Atherosclerosis; Cell Division; Cells, Cultured; CHO Cells; Cholesterol; Coronary Vessels; Cricetinae; Cricetulus; Endothelial Cells; Enzyme Inhibitors; Humans; In Vitro Techniques; Lipoproteins, HDL; Lysophospholipids; Macrophages; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase Type III; Oligonucleotides, Antisense; Phosphatidylcholines; Proto-Oncogene Proteins c-akt; ras Proteins; Sphingosine