title: Systemic Gene Silencing in Primary T Lymphocytes Using Targeted Lipid Nanoparticles.
abstract: Modulating T cell function by down-regulating specific genes using RNA interference (RNAi) holds tremendous potential in advancing targeted therapies in many immune-related disorders including cancer, inflammation, autoimmunity, and viral infections. Hematopoietic cells, in general, and primary T lymphocytes, in particular, are notoriously hard to transfect with small interfering RNAs (siRNAs). Herein, we describe a novel strategy to specifically deliver siRNAs to murine CD4(+) T cells using targeted lipid nanoparticles (tLNPs). To increase the efficacy of siRNA delivery, these tLNPs have been formulated with several lipids designed to improve the stability and efficacy of siRNA delivery. The tLNPs were surface-functionalized with anti-CD4 monoclonal antibody to permit delivery of the siRNAs specifically to CD4(+) T lymphocytes. Ex vivo, tLNPs demonstrated specificity by targeting only primary CD4(+) T lymphocytes and no other cell types. Systemic intravenous administration of these particles led to efficient binding and uptake into CD4(+) T lymphocytes in several anatomical sites including the spleen, inguinal lymph nodes, blood, and the bone marrow. Silencing by tLNPs occurs in a subset of circulating and resting CD4(+) T lymphocytes. Interestingly, we show that tLNP internalization and not endosome escape is a fundamental event that takes place as early as 1 h after systemic administration and determines tLNPs' efficacy. Taken together, these results suggest that tLNPs may open new avenues for the manipulation of T cell functionality and may help to establish RNAi as a therapeutic modality in leukocyte-associated diseases.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Ramishetti
authors.forename: Ranit
authors.initials: R
authors.lastname: Kedmi
authors.forename: Meir
authors.initials: M
authors.lastname: Goldsmith
authors.affiliation: ⊥Department of NanoMedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States.
authors.forename: Fransisca
authors.initials: F
authors.lastname: Leonard
authors.affiliation: ∥Alnylam Pharmaceuticals, Cambridge, Massachusetts 02142, United States.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Sprague
authors.affiliation: ⊥Department of NanoMedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States.
authors.forename: Biana
authors.initials: B
authors.lastname: Godin
authors.forename: Michael
authors.initials: M
authors.lastname: Gozin
authors.forename: Pieter R
authors.initials: PR
authors.lastname: Cullis
authors.affiliation: △Dr. John T Macdonald Foundation, Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, Florida 33136, United States.
authors.forename: Derek M
authors.initials: DM
authors.lastname: Dykxhoorn
authors.forename: Dan
authors.initials: D
authors.lastname: Peer
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism* / Q000637:transplantation; D002478:Cells, Cultured; D020868:Gene Silencing; D008055:Lipids / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D000067492:RNAi Therapeutics / Q000379:methods
chemical_list: D008055:Lipids; D034741:RNA, Small Interfering
keywords: CD45; RNA interference; T lymphocytes; lipid-based nanoparticles