title: An amphipathic alpha-helical peptide from apolipoprotein A1 stabilizes protein polymer vesicles.
abstract: L4F, an alpha helical peptide inspired by the lipid-binding domain of the ApoA1 protein, has potential applications in the reduction of inflammation involved with cardiovascular disease as well as an antioxidant effect that inhibits liver fibrosis. In addition to its biological activity, amphipathic peptides such as L4F are likely candidates to direct the molecular assembly of peptide nanostructures. Here we describe the stabilization of the amphipathic L4F peptide through fusion to a high molecular weight protein polymer. Comprised of multiple pentameric repeats, elastin-like polypeptides (ELPs) are biodegradable protein polymers inspired from the human gene for tropoelastin. Dynamic light scattering confirmed that the fusion peptide forms nanoparticles with a hydrodynamic radius of approximately 50nm, which is unexpectedly above that observed for the free ELP (~5.1nm). To further investigate their morphology, conventional and cryogenic transmission electron microscopy were used to reveal that they are unilamellar vesicles. On average, these vesicles are 49nm in radius with lamellae 8nm in thickness. To evaluate their therapeutic potential, the L4F nanoparticles were incubated with hepatic stellate cells. Stellate cell activation leads to hepatic fibrosis; furthermore, their activation is suppressed by anti-oxidant activity of ApoA1 mimetic peptides. Consistent with this observation, L4F nanoparticles were found to suppress hepatic stellate cell activation in vitro. To evaluate the in vivo potential for these nanostructures, their plasma pharmacokinetics were evaluated in rats. Despite the assembly of nanostructures, both free L4F and L4F nanoparticles exhibited similar half-lives of approximately 1h in plasma. This is the first study reporting the stabilization of peptide-based vesicles using ApoA1 mimetic peptides fused to a protein polymer; furthermore, this platform for peptide-vesicle assembly may have utility in the design of biodegradable nanostructures.
authors.affiliation: Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA.
authors.forename: Martha K
authors.initials: MK
authors.lastname: Pastuszka
authors.affiliation: Research Center for Liver Diseases and the Division of Gastrointestinal and Liver Diseases, Keck School of Medicine at the University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Lye Lin
authors.initials: LL
authors.lastname: Lock
authors.affiliation: Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA.
authors.forename: Siti Mohd
authors.initials: SM
authors.lastname: Janib
authors.affiliation: Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Honggang
authors.initials: H
authors.lastname: Cui
authors.affiliation: Research Center for Liver Diseases and the Division of Gastrointestinal and Liver Diseases, Keck School of Medicine at the University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Laurie D
authors.initials: LD
authors.lastname: DeLeve
authors.affiliation: Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA; Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA. Electronic address: jamackay@usc.edu.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: MacKay
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D016632:Apolipoprotein A-I / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000493:pharmacokinetics; D002478:Cells, Cultured; D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D005818:Genetic Engineering; D006207:Half-Life; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism; D007275:Injections, Intravenous; D051379:Mice; D053758:Nanoparticles; D036103:Nanotechnology; D010316:Particle Size; D010446:Peptide Fragments / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000493:pharmacokinetics; D055550:Protein Stability; D017433:Protein Structure, Secondary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods; D014333:Tropoelastin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D016632:Apolipoprotein A-I; D004337:Drug Carriers; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D014333:Tropoelastin
keywords: Cryo-TEM; Elastin-like polypeptide; Hydrodynamic radius; L-4F; Nanoparticle; Vesicle