title: Selective transfection of microglia in the brain using an antibody-based non-viral vector.
abstract: There are currently few approaches to transiently manipulate the expression of specific proteins in microglia of the brain. An antibody directed against an extracellular epitope of scavenger receptor class B, type I (SR-BI) was found to be selectively taken up by these cells in the brain. Other antibodies tested were not internalised by microglia. A vector was produced by linking the SR-BI antibody to polyethyleneimine and binding a DNA plasmid encoding green fluorescent protein. Infusions of this vector into the hippocampus produced a widespread transfection of cells, more than 80% of which were immunoreactive for microglial/macrophage markers. Transfection was not detected in cells expressing markers for astrocytes or neurons. Reporter gene expression was most prominent near the infusion site but was seen in tissue up to 4mm away. DNA bound to polyethyleneimine alone or to a vector containing a different antibody did not produce transfection in the brain. Single injections of the vector containing the SR-BI antibody into the brain also resulted in transfection of microglia, albeit with lower efficiency. Vector modifications to promote lysis of endosomes or entry of DNA into the nucleus did not increase efficiency. The findings clearly demonstrate the capacity of the SR-BI antibody to selectively target brain microglia. This approach offers considerable potential to deliver DNA and other molecules capable of modifying the function of these cells in vivo.
authors.affiliation: Centre for Neuroscience, Flinders Medical Science and Technology, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Malmevik
authors.affiliation: Centre for Neuroscience, Flinders Medical Science and Technology, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia.
authors.forename: M-L
authors.initials: ML
authors.lastname: Rogers
authors.affiliation: Hunter Medical Research Institute (HMRI), University of Newcastle, Australia; Centre for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Nilsson
authors.affiliation: Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakanishi
authors.affiliation: Centre for Neuroscience, Flinders Medical Science and Technology, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Rush
authors.affiliation: Centre for Neuroscience, Flinders Medical Science and Technology, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia.
authors.forename: N R
authors.initials: NR
authors.lastname: Sims
authors.affiliation: Centre for Neuroscience, Flinders Medical Science and Technology, Flinders University, GPO Box 2100, Adelaide SA 5001, Australia. Electronic address: hakan.muyderman@flinders.edu.au.
authors.forename: H
authors.initials: H
authors.lastname: Muyderman
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000502:physiology*; D000914:Antibodies, Viral; D001921:Brain / Q000166:cytology*; D039481:CD11b Antigen / Q000378:metabolism; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000502:physiology*; D005822:Genetic Vectors / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D017628:Microglia / Q000378:metabolism*; D011094:Polyethyleneimine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051122:Scavenger Receptors, Class B / Q000276:immunology* / Q000378:metabolism; D013997:Time Factors; D014162:Transfection / Q000379:methods*
chemical_list: D000906:Antibodies; D000914:Antibodies, Viral; D039481:CD11b Antigen; C495125:Scarb1 protein, rat; D051122:Scavenger Receptors, Class B; D049452:Green Fluorescent Proteins; D011094:Polyethyleneimine
keywords: Antibody; Immunoporter; Microglia; Non-viral; Receptor-mediated gene delivery; Targeted gene delivery