title: Conjugation of palmitic acid improves potency and longevity of siRNA delivered via endosomolytic polymer nanoparticles.
abstract: Clinical translation of siRNA therapeutics has been limited by the inability to effectively overcome the rigorous delivery barriers associated with intracellular-acting biologics. Here, to address both potency and longevity of siRNA gene silencing, pH-responsive micellar nanoparticle (NP) carriers loaded with siRNA conjugated to palmitic acid (siRNA-PA) were investigated as a combined approach to improve siRNA endosomal escape and stability. Conjugation to hydrophobic PA improved NP loading efficiency relative to unmodified siRNA, enabling complete packaging of siRNA-PA at a lower polymer:siRNA ratio. PA conjugation also increased intracellular uptake of the nucleic acid cargo by 35-fold and produced a 3.1-fold increase in intracellular half-life. The higher uptake and improved retention of siRNA-PA NPs correlated to a 2- and 11-fold decrease in gene silencing IC50 in comparison to siRNA NPs in fibroblasts and mesenchymal stem cells, respectively, for both the model gene luciferase and the therapeutically relevant gene prolyl hydroxylase domain protein 2 (PHD2) . PA conjugation also significantly increased longevity of silencing activity following a single treatment in fibroblasts. Thus, conjugation of PA to siRNA paired with endosomolytic NPs is a promising approach to enhance the functional efficacy of siRNA in tissue regenerative and other applications.
authors: Department of Biomedical Engineering, Vanderbilt University, VU Station B 351631, Nashville, Tennessee, 37235-1631.
authors: Samantha M
authors: SM
authors: Sarett
authors: Department of Biomedical Engineering, Vanderbilt University, VU Station B 351631, Nashville, Tennessee, 37235-1631.
authors: Kameron V
authors: KV
authors: Kilchrist
authors: Department of Biomedical Engineering, Vanderbilt University, VU Station B 351631, Nashville, Tennessee, 37235-1631.
authors: Martina
authors: M
authors: Miteva
authors: Department of Biomedical Engineering, Vanderbilt University, VU Station B 351631, Nashville, Tennessee, 37235-1631.
authors: Craig L
authors: CL
authors: Duvall
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001693:Biological Transport, Active; D016503:Drug Delivery Systems; D011992:Endosomes / Q000378:metabolism; D020868:Gene Silencing; D057809:HEK293 Cells; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D019308:Palmitic Acid / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000493:pharmacokinetics
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D034741:RNA, Small Interfering; D019308:Palmitic Acid
keywords: endosomolytic nanoparticle; gene knockdown; siRNA conjugation
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