title: PEGylated polyplex with optimized PEG shielding enhances gene introduction in lungs by minimizing inflammatory responses.
abstract: Safety is a critical issue in clinical applications of nonviral gene delivery systems. Safe and effective gene introduction into the lungs was previously achieved using polyplexes from poly(ethyleneglycol) (PEG)-block-polycation [PEG-block-PAsp(DET)] and plasmid DNA (pDNA). Although PEGylated polyplexes appeared to be safe, an excess ratio of polycation to pDNA was needed to obtain sufficient transgene expression, which may cause toxicities shortly after gene introduction. In the present study, we investigated the combined use of two polymers, PEG-block-PAsp(DET) (B) and homo PAsp(DET) (H) across a range of mixing ratios to construct polyplexes. Although transgene expressions following in vitro transfections increased in parallel with increased proportions of H, polyplexes with B/H = 50/50 formulation produced the highest expression level following in vivo intratracheal administration. Higher proportions of H elicited high levels of cytokine induction with significant inflammation as assessed by histopathological examinations. Based on the aggregation behavior of polyplexes in bronchoalveolar lavage fluids (BALFs), we suggested that rapid aggregation of polyplexes in the lung induced acute inflammatory responses, resulting in reduced transgene expression. B/H formulation of polyplex can help to improve gene therapy for the respiratory system because it achieves both effective PEG shielding of polyplexes and functioning of PAsp(DET) polycations to enhance endosomal escape.
authors.affiliation: Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uchida
authors.forename: Keiji
authors.initials: K
authors.lastname: Itaka
authors.forename: Qixian
authors.initials: Q
authors.lastname: Chen
authors.forename: Kensuke
authors.initials: K
authors.lastname: Osada
authors.forename: Takehiko
authors.initials: T
authors.lastname: Ishii
authors.forename: Masa-Aki
authors.initials: MA
authors.lastname: Shibata
authors.forename: Mariko
authors.initials: M
authors.lastname: Harada-Shiba
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D011014:Pneumonia / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D011073:Polyamines; D000071228:Polyelectrolytes; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000378:metabolism; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D014162:Transfection; D019076:Transgenes
chemical_list: D016207:Cytokines; D004247:DNA; D011073:Polyamines; D000071228:Polyelectrolytes; D011092:Polyethylene Glycols; D011108:Polymers