title: Drug delivery system based on responses to an HIV infectious signal.
abstract: Gene therapy is a growing topic in the medical arena. Since the safety system of gene therapy has not been sufficiently established, its clinical use is limited. Recently, we developed a cell-specific gene regulation system based on a new concept, D-RECS, or Drug and Gene Delivery System Responding to Cellular Signals. We hoped here to apply this D-RECS concept to gene therapy for virus infections. In the present study, we report the design, synthesis and characterization of the functional polymers, which are able to discriminate normal and human immunodeficiency virus type 1 (HIV-1) infected cells. In the D-RECS concept, certain intracellular signals, which are extraordinary activated in the target disease cells specifically, are used as a trigger to activate a transgene expression. Thus, we paid attention to HIV protease as a target signal in this case, because HIV protease is essential for the proliferation of HIV. This protease is therefore an indicator of HIV infection. Two types of polymers were designed and synthesized using methacryloyl peptide and acrylamide with radical copolymerization as a functional gene regulator. The grafted peptide possesses a cationic protein transduction domain (PTD) sequence of HIV-Tat protein, GRKKRRQRRRPPQ for cell permeation, which are connected with polyacrylamide backbone via a consensus substrate sequence for HIV protease, SQNY/PIVQ. At first, the polymers were evaluated to see whether they possess DNA binding ability and HIV protease responsibility using gel retardation assay. The results suggested that a polymer could form a stable complex with DNA and release the DNA specifically responding to HIV protease activity. Furthermore, it was shown that this controlled release of DNA by the HIV protease signal-responsive intelligent polymer actually regulated the gene expression in the cell-free system. This system would be a useful tool for gene therapy in HIV infection, and this methodology will be applicable if the cationic peptide is replaced by another virus-specific protease, which is critical for the replication of a corresponding virus.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Asai
authors.forename: Kota Bae
authors.initials: KB
authors.lastname: Kodama
authors.forename: Yoko
authors.initials: Y
authors.lastname: Shoji
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakashima
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawamura
authors.forename: Jun
authors.initials: J
authors.lastname: Oishi
authors.forename: Masanori
authors.initials: M
authors.lastname: Kuramoto
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations / Q000737:chemistry; D002474:Cell-Free System; D016503:Drug Delivery Systems; D005786:Gene Expression Regulation; D006678:HIV / Q000187:drug effects* / Q000201:enzymology*; D016333:HIV Protease / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D002412:Cations; D010455:Peptides; D016333:HIV Protease