title: Antisense peptide nucleic acid-mediated knockdown of the p75 neurotrophin receptor delays motor neuron disease in mutant SOD1 transgenic mice.
abstract: Re-expression of the death-signalling p75 neurotrophin receptor (p75NTR) is associated with injury and neurodegeneration in the adult nervous system. The induction of p75NTR expression in mature degenerating spinal motor neurons of humans and transgenic mice with amyotrophic lateral sclerosis (ALS) suggests a role of p75NTR in the progression of motor neuron disease (MND). In this study, we designed, synthesized and evaluated novel antisense peptide nucleic acid (PNA) constructs targeting p75NTR as a potential gene knockdown therapeutic strategy for ALS. An 11-mer antisense PNA directed at the initiation codon, but not downstream gene sequences, dose-dependently inhibited p75NTR expression and death-signalling by nerve growth factor (NGF) in Schwann cell cultures. Antisense phosphorothioate oligonucleotide (PS-ODN) sequences used for comparison failed to confer such inhibitory activity. Systemic intraperitoneal administration of this antisense PNA to mutant superoxide dismutase 1 (SOD1G93A) transgenic mice significantly delayed locomotor impairment and mortality compared with mice injected with nonsense or scrambled PNA sequences. Reductions in p75NTR expression and subsequent caspase-3 activation in spinal cords were consistent with increased survival in antisense PNA-treated mice. The uptake of fluorescent-labelled antisense PNA in the nervous system of transgenic mice was also confirmed. This study suggests that p75NTR may be a promising antisense target in the treatment of ALS.
authors.affiliation: Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Turner
authors.forename: Irwin K
authors.initials: IK
authors.lastname: Cheah
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Macfarlane
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Lopes
authors.forename: Steven
authors.initials: S
authors.lastname: Petratos
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Langford
authors.forename: Surindar S
authors.initials: SS
authors.lastname: Cheema
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000628:therapy*; D000818:Animals; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D005456:Fluorescent Dyes; D015316:Genetic Therapy / Q000379:methods*; D051379:Mice; D008822:Mice, Transgenic; D020932:Nerve Growth Factor / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D020135:Peptide Nucleic Acids / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D012583:Schwann Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000235:genetics
chemical_list: D005456:Fluorescent Dyes; D016376:Oligonucleotides, Antisense; D020135:Peptide Nucleic Acids; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D020932:Nerve Growth Factor; C109415:SOD1 G93A protein; D013482:Superoxide Dismutase; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases