Global down-regulation of gene expression in the brain using RNA interference, with emphasis on monoamine transporters and GPCRs: implications for target characterization in psychiatric and neurological disorders.
RNA interference (RNAi) is a natural mechanism for regulating gene expression, which exists in plants, invertebrates, and mammals. We investigated whether non-viral infusion of short interfering RNA (siRNA) by the intracerebroventricular route would enable a sequence-specific gene knockdown in the mouse brain and whether the knockdown translates into disease-relevant behavioral changes. Initially, we targeted enhanced green fluorescent protein (EGFP) in mice overexpressing EGFP. A selective knockdown of both EGFP protein and mRNA was observed throughout the brain, with lesser down-regulation in regions distal to the infusion site. We then targeted endogenous genes, encoding the dopamine (DAT) and serotonin transporters (SERT). DAT-siRNA infusion in adult mice produced a significant down-regulation of DAT mRNA and protein and elicited hyperlocomotion similar, but delayed, to that produced on infusion of GBR-12909, a potent and selective DAT inhibitor. Similarly, SERT-siRNA infusion resulted in significant knockdown of SERT mRNA and protein and elicited reduced immobility in the forced swim test similar to that obtained on infusion of citalopram, a very selective and potent SSRI. Application of this non-viral RNAi approach may accelerate target validation for neuropsychiatric disorders that involve a complex interplay of gene(s) from various brain regions.
Hoyer
Daniel
D
Psychiatry Program, Neuroscience Research, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland. daniel.hoyer@novartis.com
Thakker
Deepak R
DR
Natt
François
F
Maier
Rainer
R
Huesken
Dieter
D
Müller
Matthias
M
Flor
Peter
P
VAN DER Putten
Herman
H
Schmutz
Markus
M
Bilbe
Graeme
G
Cryan
John F
JF
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D049452:Green Fluorescent Proteins / Q000235:genetics; D008124:Locomotion / Q000187:drug effects; D001523:Mental Disorders / Q000188:drug therapy; D051379:Mice; D009422:Nervous System Diseases / Q000188:drug therapy; D050480:Plasma Membrane Neurotransmitter Transport Proteins / Q000235:genetics*; D034622:RNA Interference / Q000187:drug effects*; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000187:drug effects / Q000235:genetics
D050483:Dopamine Plasma Membrane Transport Proteins; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; D050486:Serotonin Plasma Membrane Transport Proteins; D049452:Green Fluorescent Proteins