title: Non-viral gene therapy that targets motor neurons in vivo.
abstract: A major challenge in neurological gene therapy is safe delivery of transgenes to sufficient cell numbers from the circulation or periphery. This is particularly difficult for diseases involving spinal cord motor neurons such as amyotrophic lateral sclerosis (ALS). We have examined the feasibility of non-viral gene delivery to spinal motor neurons from intraperitoneal injections of plasmids carried by "immunogene" nanoparticles targeted for axonal retrograde transport using antibodies. PEGylated polyethylenimine (PEI-PEG12) as DNA carrier was conjugated to an antibody (MLR2) to the neurotrophin receptor p75 (p75NTR). We used a plasmid (pVIVO2) designed for in vivo gene delivery that produces minimal immune responses, has improved nuclear entry into post mitotic cells and also expresses green fluorescent protein (GFP). MLR2-PEI-PEG12 carried pVIVO2 and was specific for mouse motor neurons in mixed cultures containing astrocytes. While only 8% of motor neurons expressed GFP 72 h post transfection in vitro, when the immunogene was given intraperitonealy to neonatal C57BL/6J mice, GFP specific motor neuron expression was observed in 25.4% of lumbar, 18.3% of thoracic and 17.0% of cervical motor neurons, 72 h post transfection. PEI-PEG12 carrying pVIVO2 by itself did not transfect motor neurons in vivo, demonstrating the need for specificity via the p75NTR antibody MLR2. This is the first time that specific transfection of spinal motor neurons has been achieved from peripheral delivery of plasmid DNA as part of a non-viral gene delivery agent. These results stress the specificity and feasibility of immunogene delivery targeted for p75NTR expressing motor neurons, but suggests that further improvements are required to increase the transfection efficiency of motor neurons in vivo.
authors.affiliation: Department of Human Physiology, Centre for Neuroscience, Flinders University Adelaide, SA, Australia.
authors.forename: Mary-Louise
authors.initials: ML
authors.lastname: Rogers
authors.affiliation: Department of Human Physiology, Centre for Neuroscience, Flinders University Adelaide, SA, Australia.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Smith
authors.affiliation: Department of Anatomy and Histology, Centre for Neuroscience, Flinders University Adelaide, SA, Australia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Matusica
authors.affiliation: Department of Human Physiology, Centre for Neuroscience, Flinders University Adelaide, SA, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Fenech
authors.affiliation: Department of Chemistry and Biochemistry, South Dakota State University Brookings, SD, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Hoffman
authors.affiliation: Department of Human Physiology, Centre for Neuroscience, Flinders University Adelaide, SA, Australia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rush
authors.affiliation: Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Mawson Institute, University of South Australia Adelaide, SA, Australia.
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: Voelcker
keywords: PEGylation; PEI; immunogenes; p75NTR; retrograde transport; targeted gene delivery