title: Tf-lipoplexes for neuronal siRNA delivery: a promising system to mediate gene silencing in the CNS.
abstract: Although RNAi-based gene silencing holds a great potential for treatment of neurological disorders, its application to the CNS has been restricted by low levels of tissue distribution and cellular uptake. In this work we report that cationic lipid-based vectors can enhance siRNA delivery to neurons both in vitro and in vivo. DOTAP:Chol liposomes associated with transferrin (Tf) and complexed with siRNAs (Tf-lipoplexes) were delivered to primary cultures of luciferase-expressing cortical neurons. Confocal microscopy studies revealed efficient cellular uptake of Cy3-labelled siRNAs after Tf-lipoplex delivery, which was reduced but not completely inhibited by blocking the Tf-receptor with excess Tf. Gene silencing was also evaluated after delivery of anti-luciferase or anti-c-Jun siRNAs. Our results demonstrate that Tf-lipoplexes achieve up to 50% luciferase and c-Jun knockdown, 48 h after transfection, without significant cytotoxicity. Similar results were observed in vivo, where a 40% reduction of luciferase activity was found in the striatum of luciferase mice. In addition, fluorescence microscopy studies showed extensive local distribution and internalization of Tf-lipoplex-associated Cy3-siRNAs without tissue toxicity. Overall, our results demonstrate that Tf-lipoplexes can mediate efficient gene silencing in neuronal cells, both in vitro an in vivo, which may prove useful in therapeutic approaches to neuronal protection and repair.
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: A L C
authors.initials: AL
authors.lastname: Cardoso
authors.forename: S
authors.initials: S
authors.lastname: Simões
authors.forename: L P
authors.initials: LP
authors.lastname: de Almeida
authors.forename: N
authors.initials: N
authors.lastname: Plesnila
authors.forename: M C
authors.initials: MC
authors.lastname: Pedroso de Lima
authors.forename: E
authors.initials: E
authors.lastname: Wagner
authors.forename: C
authors.initials: C
authors.lastname: Culmsee
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism*; D002784:Cholesterol / Q000737:chemistry; D003593:Cytoplasm / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D015870:Gene Expression; D020868:Gene Silencing; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000633:toxicity; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D014162:Transfection; D014168:Transferrin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D005229:Fatty Acids, Monounsaturated; D008055:Lipids; C086724:Lipofectamine; D008081:Liposomes; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; D014168:Transferrin; D002784:Cholesterol; D008156:Luciferases; D048031:JNK Mitogen-Activated Protein Kinases; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane