2. Academic Validation
  3. The novel compound PBT434 prevents iron mediated neurodegeneration and alpha-synuclein toxicity in multiple models of Parkinson's disease

The novel compound PBT434 prevents iron mediated neurodegeneration and alpha-synuclein toxicity in multiple models of Parkinson's disease

  • Acta Neuropathol Commun. 2017 Jun 28;5(1):53. doi: 10.1186/s40478-017-0456-2.
David I Finkelstein 1,  Jessica L Billings 2,  Paul A Adlard 2,  Scott Ayton 2,  Amelia Sedjahtera 2,  Colin L Masters 2,  Simon Wilkins 2,  David M Shackleford 3,  Susan A Charman 3,  Wojciech Bal 4,  Izabela A Zawisza 4,  Ewa Kurowska 4,  Andrew L Gundlach 2,  Sheri Ma 2,  Ashley I Bush 2,  Dominic J Hare 2 5,  Philip A Doble 5,  Simon Crawford 6,  Elisabeth Cl Gautier 7,  Jack Parsons 7,  Penny Huggins 7,  Kevin J Barnham 2 8,  Robert A Cherny 9 10
Affiliations

Affiliations

  • 1 The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia. [email protected].
  • 2 The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia.
  • 3 Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.
  • 4 The Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
  • 5 Elemental Bio-imaging Facility, The University of Technology Sydney, Broadway, Ultimo, NSW, 2007, Australia.
  • 6 Australia Electron Microscope Unit, School of Biosciences, The University of Melbourne, Melbourne, VIC, 3010, Australia.
  • 7 Prana Biotechnology Ltd, Parkville, VIC, 3052, Australia.
  • 8 Bio21 Institute and Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.
  • 9 The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia. [email protected].
  • 10 Prana Biotechnology Ltd, Parkville, VIC, 3052, Australia. [email protected].
PMID: 28659169 DOI: 10.1186/s40478-017-0456-2
Abstract

Elevated iron in the SNpc may play a key role in Parkinson's disease (PD) neurodegeneration since drug candidates with high iron affinity rescue PD animal models, and one candidate, deferirpone, has shown efficacy recently in a phase two clinical trial. However, strong iron chelators may perturb essential iron metabolism, and it is not yet known whether the damage associated with iron is mediated by a tightly bound (eg ferritin) or lower-affinity, labile, iron pool. Here we report the preclinical characterization of PBT434, a novel quinazolinone compound bearing a moderate affinity metal-binding motif, which is in development for Parkinsonian conditions. In vitro, PBT434 was far less potent than deferiprone or deferoxamine at lowering cellular iron levels, yet was found to inhibit iron-mediated redox activity and iron-mediated aggregation of α-synuclein, a protein that aggregates in the neuropathology. In vivo, PBT434 did not deplete tissue iron stores in normal rodents, yet prevented loss of substantia nigra pars compacta neurons (SNpc), lowered nigral α-synuclein accumulation, and rescued motor performance in mice exposed to the Parkinsonian toxins 6-OHDA and MPTP, and in a transgenic animal model (hA53T α-synuclein) of PD. These improvements were associated with reduced markers of oxidative damage, and increased levels of Ferroportin (an iron exporter) and DJ-1. We conclude that compounds designed to target a pool of pathological iron that is not held in high-affinity complexes in the tissue can maintain the survival of SNpc neurons and could be disease-modifying in PD.

Keywords

Chelation; Drug development; Neuroprotection; Oxidative stress; Synucleinopathy.

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