title: A rapid, targeted, neuron-selective, in vivo knockdown following a single intracerebroventricular injection of a novel chemically modified siRNA in the adult rat brain.
abstract: There has been a dramatic expansion of the literature on RNA interference and with it, increasing interest in the potential clinical utility of targeted inhibition of gene expression and associated protein knockdown. However, a critical factor limiting the experimental and therapeutic application of RNA interference is the ability to deliver small interfering RNAs (siRNAs), particularly in the central nervous system, without complications such as toxicity and inflammation. Here we show that a single intracerebroventricular injection of Accell siRNA, a new type of naked siRNA that has been modified chemically to allow for delivery in the absence of transfection reagents, even into differentiated cells such mature neurons, leads to neuron-specific protein knockdown in the adult rat brain. Following in vivo delivery, targeted Accell siRNAs were incorporated successfully into various types of mature neurons, but not glia, for 1 week in diverse brain regions (cortex, striatum, hippocampus, midbrain, and cerebellum) with an efficacy of delivery of approximately 97%. Immunohistochemical and Western blotting analyses revealed widespread, targeted inhibition of the expression of two well-known reference proteins, cyclophilin-B (38-68% knockdown) and glyceraldehyde 3-phosphate dehydrogenase (23-34% knockdown). These findings suggest that this novel procedure is likely to be useful in experimental investigations of neuropathophysiological mechanisms.
authors.affiliation: Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka 5988531, Japan. hnakajima@vet.osakafu-u.ac.jp
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Nakajima
authors.forename: Takeya
authors.initials: T
authors.lastname: Kubo
authors.forename: Yuko
authors.initials: Y
authors.lastname: Semi
authors.forename: Masanori
authors.initials: M
authors.lastname: Itakura
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kuwamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Izawa
authors.forename: Yasu-Taka
authors.initials: YT
authors.lastname: Azuma
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Takeuchi
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism; D016503:Drug Delivery Systems; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques / Q000379:methods*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D007276:Injections, Intraventricular; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051381:Rats
chemical_list: D034741:RNA, Small Interfering; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D021983:Cyclophilins