Non-invasive gene targeting to the fetal brain after intravenous administration and transplacental transfer of plasmid DNA using PEGylated immunoliposomes

Abstract

Research was undertaken to establish transplacental delivery of active genes to fetal brain by a non-viral vector, antibody-specific targeted therapeutic procedure. PEGylated immunoliposomes (PILs) containing firefly luciferase DNA under the influence of the SV40 promoter injected intravenously into near-term pregnant mice produced luminometric evidence of CNS tissue luciferase activity at 48-h post-injection in all newborn pups. In utero delivery of this pGL3 DNA was shown after a single i.v. injection in maternal and neonatal brains, spleen and lesser amounts in lungs, with only negligible background levels in negative controls exposed to unencapsulated pDNA. In addition to studies of normal wild-type mice, we similarly injected pregnant Lafora Knockout (EPM2a null-mutant) and demonstrated luciferase activity days later in the maternal and newborn pup brains of both types. Delivery of PILs containing a second reporter gene (the pSV40 beta-galactosidase transgene) transplacentally by the same procedure was also successful. Histochemical and biochemical demonstration of beta-galactosidase was documented for all mutant and non-mutant neonates. Brain areas of highest Lafora body development (such as the hippocampus and pontine nuclei) showed intraneuronal beta-glucosidase activity. We conclude that receptor-mediated transport of PIL-borne gene therapeutics across both the placental barrier as well as the fetal BBB in utero is feasible.

• Adult and fetal blood–brain barrier
• EPM2a null mutant mice
• Lafora's disease
• non-invasive gene delivery
• PEGylated immunoliposome
• transferrin receptor-mediated endocytosis
• transplacental gene transfer

Acknowledgements

We thank Dr Jeffery Gornbein (Department of Biostatistics, UCLA) for assistance with the statistical analyses and Dr Antonio V. Delgado-Escueta (Department of Neurology) for the gift of the Lafora mouse colony. The B-cell lymphoma cell line 38C13t was a gift from Drs Ronald and Shoshana Levy, Stanford University, Stanford, CA.

Declaration of interest

Supported by grants from the National Institutes of Health [1RO1 NS 052456], France Lafora, and the Lysosomal Storage Diseases Research Consortium. The authors report no declarations of interest.