title: Silencing of reporter gene expression in skin using siRNAs and expression of plasmid DNA delivered by a soluble protrusion array device (PAD).
abstract: Despite rapid progress in the development of potent and selective small interfering RNA (siRNA) agents for skin disorders, translation to the clinic has been hampered by the lack of effective, patient-friendly delivery technologies. The stratum corneum poses a formidable barrier to efficient delivery of large and/or charged macromolecules including siRNAs. Intradermal siRNA injection results in effective knockdown of targeted gene expression but is painful and the effects are localized to the injection site. The use of microneedle arrays represents a less painful delivery method and may have utility for the delivery of nucleic acids, including siRNAs. For this purpose, we developed a loadable, dissolvable protrusion array device (PAD) that allows skin barrier penetration. The PAD tips dissolve upon insertion, forming a gel-like plug that releases functional cargo. PAD-mediated delivery of siRNA (modified for enhanced stability and cellular uptake) resulted in effective silencing of reporter gene expression in a transgenic reporter mouse model. PAD delivery of luciferase reporter plasmids resulted in expression in cells of the ear, back, and footpad skin as assayed by intravital bioluminescence imaging. These results support the use of PADs for delivery of functional nucleic acids to cells in the skin with an efficiency that may support clinical translation.
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Emilio
authors.initials: E
authors.lastname: Gonzalez-Gonzalez
authors.forename: Tycho J
authors.initials: TJ
authors.lastname: Speaker
authors.forename: Robyn P
authors.initials: RP
authors.lastname: Hickerson
authors.forename: Ryan
authors.initials: R
authors.lastname: Spitler
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Flores
authors.forename: Devin
authors.initials: D
authors.lastname: Leake
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Contag
authors.forename: Roger L
authors.initials: RL
authors.lastname: Kaspar
mesh_terms: D000818:Animals; D004337:Drug Carriers; D005260:Female; D005528:Foot; D020868:Gene Silencing / Q000502:physiology; D017930:Genes, Reporter / Q000235:genetics*; D051379:Mice; D008856:Microscopy, Fluorescence; D010957:Plasmids / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology*; D012867:Skin / Q000378:metabolism*
chemical_list: D004337:Drug Carriers; D034741:RNA, Small Interfering