title: Targeted gene transfer to the brain via the delivery of brain-penetrating DNA nanoparticles with focused ultrasound.
abstract: Gene therapy holds promise for the treatment of many pathologies of the central nervous system (CNS), including brain tumors and neurodegenerative diseases. However, the delivery of systemically administered gene carriers to the CNS is hindered by both the blood-brain barrier (BBB) and the nanoporous and electrostatically charged brain extracelluar matrix (ECM), which acts as a steric and adhesive barrier. We have previously shown that these physiological barriers may be overcome by, respectively, opening the BBB with MR image-guided focused ultrasound (FUS) and microbubbles and using highly compact "brain penetrating" nanoparticles (BPN) coated with a dense polyethylene glycol corona that prevents adhesion to ECM components. Here, we tested whether this combined approach could be utilized to deliver systemically administered DNA-bearing BPN (DNA-BPN) across the BBB and mediate localized, robust, and sustained transgene expression in the rat brain. Systemically administered DNA-BPN delivered through the BBB with FUS led to dose-dependent transgene expression only in the FUS-treated region that was evident as early as 24h post administration and lasted for at least 28days. In the FUS-treated region ~42% of all cells, including neurons and astrocytes, were transfected, while less than 6% were transfected in the contralateral non-FUS treated hemisphere. Importantly, this was achieved without any sign of toxicity or astrocyte activation. We conclude that the image-guided delivery of DNA-BPN with FUS and microbubbles constitutes a safe and non-invasive strategy for targeted gene therapy to the brain.
authors.affiliation: Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Mead
authors.affiliation: Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Neurological Surgery, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Mastorakos
authors.affiliation: Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Suk
authors.affiliation: Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA; Cardiovascular Division, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Klibanov
authors.affiliation: Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA. Electronic address: hanes@jhmi.edu.
authors.forename: Justin
authors.initials: J
authors.lastname: Hanes
authors.affiliation: Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA. Electronic address: rprice@virginia.edu.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Price
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004247:DNA / Q000008:administration & dosage* / Q000737:chemistry; D005260:Female; D018014:Gene Transfer Techniques; D045423:Microbubbles; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D017207:Rats, Sprague-Dawley; D000069453:Ultrasonic Waves
chemical_list: D011092:Polyethylene Glycols; D004247:DNA
keywords: Blood–brain barrier; CNS diseases; Focused ultrasound; Non-viral gene delivery