title: Optimizing size and copy number for PEG-fMLF (N-formyl-methionyl-leucyl-phenylalanine) nanocarrier uptake by macrophages.
abstract: Curing HIV-1 infection has remained elusive because of low and fluctuating drug levels arising from poor absorption, the development of viral reservoirs and sanctuary sites, toxicity, and patient nonadherence. The present study addresses the issue of insufficient drug exposure in macrophages. Viral reservoir sites such as macrophages are believed to be responsible for the viral rebound effect observed upon the discontinuation of anti-HIV drug therapy. In our proposed model, a drug can be covalently attached to a nanocarrier in order to facilitate the delivery of therapeutic agents to the site(s) of infection. As an initial step, we propose the covalent attachment of several copies of N-formyl-Met-Leu-Phe (fMLF), a known chemo-attractant for macrophages. In this article, one or more copies of fMLF were conjugated to multifunctional commercially available or novel, peptide-based PEG nanocarriers in which the structure was varied by appending PEGs with average molecular weights of 5, 20, and 40 kDa. U937 cell-specific binding and cellular uptake were analyzed. The results of uptake studies indicate that (i) uptake is energy dependent and mediated by a fMLF receptor, (ii) appending only 2 copies of the targeting ligand to the multifunctional nanocarrier appears sufficient for binding in vitro, and (iii) of the three configurations studied, the nanocarrier with a molecular weight of about 20 kDa, corresponding to a size of 20-60 nm, demonstrated the highest uptake. The results of the current studies demonstrate the feasibility of targeting macrophages and the suitability of using these synthetically versatile peptide--backbone PEG nanocarriers. The convenience, flexibility and possible limitations of this nanocarrier approach are discussed.
authors: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
authors: Li
authors: L
authors: Wan
authors: Xiaoping
authors: X
authors: Zhang
authors: Shahriar
authors: S
authors: Pooyan
authors: Matthew S
authors: MS
authors: Palombo
authors: Michael J
authors: MJ
authors: Leibowitz
authors: Stanley
authors: S
authors: Stein
authors: Patrick J
authors: PJ
authors: Sinko
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000378:metabolism; D002454:Cell Differentiation; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011817:Rabbits; D044042:Receptors, Formyl Peptide / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D020298:U937 Cells / Q000166:cytology / Q000378:metabolism
chemical_list: D019380:Anti-HIV Agents; D004337:Drug Carriers; D044042:Receptors, Formyl Peptide; D011092:Polyethylene Glycols; D009240:N-Formylmethionine Leucyl-Phenylalanine