A rapid, targeted, neuron-selective, in vivo knockdown following a single intracerebroventricular injection of a novel chemically modified siRNA in the adult rat brain

• Published in: Journal of biotechnology 2012-01, Vol.157 (2), p.326-333
• Main Authors: Nakajima, Hidemitsu, Kubo, Takeya, Semi, Yuko, Itakura, Masanori, Kuwamura, Mitsuru, Izawa, Takeshi, Azuma, Yasu-Taka, Takeuchi, Tadayoshi
• Format: Article
• Language: English
• Subjects: Accell siRNA; adults; Animals; biotechnology; Brain - cytology; Brain - metabolism; Cell Differentiation; cerebellum; cortex; Cyclophilin-B; Cyclophilins - genetics; Cyclophilins - metabolism; Drug Delivery Systems; GAPDH; gene expression; Gene Expression Regulation; Gene Knockdown Techniques - methods; glyceraldehyde-3-phosphate dehydrogenase; Glyceraldehyde-3-Phosphate Dehydrogenases - genetics; Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism; hippocampus; immunohistochemistry; In vivo delivery; inflammation; Injections, Intraventricular; Neuroglia - cytology; Neuroglia - metabolism; neurons; Neurons - cytology; Neurons - metabolism; Organ Specificity; proteins; Rat brain; Rats; RNA interference; RNA, Small Interfering - chemistry; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; small interfering RNA; toxicity; transfection; Western blotting
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2011.10.003

► Accell siRNA is a new type of naked siRNA without requiring transfection reagents. ► We indicated a gene silencing of adult rat brain by Accell siRNA for the first time. ► The Accell siRNA was specifically incorporated into neuron, not into glia. ► Two proteins resulted in knockdown in wide regions of brain by the procedure. ► The presented method enables an in vivo gene silencing of brain easily and quickly. 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.