Intravenously Administered Novel Liposomes, DCL64, Deliver Oligonucleotides to Cerebellar Purkinje Cells
Cerebellar Purkinje cells (PCs) show conspicuous damages in many ataxic disorders. Targeted delivery of short nucleic acids, such as antisense oligonucleotides, to PCs may be a potential treatment for ataxic disorders, especially spinocerebellar ataxias (SCAs), which are mostly caused by a gain of toxic function of the mutant RNA or protein. However, oligonucleotides do not cross the blood-brain barrier (BBB), necessitating direct delivery into the central nervous system (CNS) through intra-thecal, intra-cisternal, intra-cerebral ventricular, or stereotactic parenchymal administration. We have developed a novel liposome (100 to 200 nm in diameter) formulation, DCL64, composed of dipalmitoyl-phosphatidylcholine, cholesterol, and poloxamer L64, which incorporates oligonucleotides efficiently (≥ 70%). Confocal microscopy showed that DCL64 was selectively taken up by brain microvascular endothelial cells by interacting with low-density lipoprotein receptor (LDLr) family members on cell surface, but not with other types of lipid receptors such as caveolin or scavenger receptor class B type 1. LDLr family members are implicated in brain microvascular endothelial cell endocytosis/transcytosis, and are abundantly localized on cerebellar PCs. Intravenous administration of DCL64 in normal mice showed distribution of oligonucleotides to the brain, preferentially in PCs. Mice that received DCL64 showed no adverse effect on hematological, hepatic, and renal functions in blood tests, and no histopathological abnormalities in major organs. These studies suggest that DCL64 delivers oligonucleotides to PCs across the BBB via intravenous injection with no detectable adverse effects. This property potentially makes DCL64 particularly attractive as a delivery vehicle in treatments of SCAs.
KeywordsBlood-brain barrier Liposomes Low-density lipoprotein receptor Oligonucleotide Purkinje cells Spinocerebellar ataxias
We are grateful to the technical support provided by University of Florida (UF) ICBR Cytometry Core, ICBR Electron Microscopy Core, MBI-UF Cell & Tissue Analysis Core, UF Molecular Pathology Core, and UF Animal Care Services.
This study was supported by UF Opportunity Grant to ATA and TA.
Compliance with Ethical Standards
Conflict of Interest
ATA is an employee and stock holder of Bio-Path Holdings, Inc. TA is Adjunct Professor of Baylor College of Medicine, and receives grants from the NIH (R01 NS083564), the National Ataxia Foundation (NAF), the Myotonic Dystrophy Foundation (MDF), and the Marigold Foundation, and has been supported by Biohaven Pharmaceuticals and Ionis Pharmaceuticals for clinical trials of their drugs, and by Pacific Biosciences for symposium honoraria. TA also serves on the Medical and Research Advisory Board of the NAF, and the Scientific Advisory Board of the MDF. ATA and TA filed a US patent application (Serial # 14/390,584).
Research Involving Animals
The animal research in this work was approved by the UF Institutional Animal Care and Use Committee (IACUC #201307878).
Research Involving Human Participants
This work does not involve human subject research.
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