Parkin depletion delays motor decline dose-dependently without overtly affecting neuropathology in α-synuclein transgenic mice
- Equal contributors
1 Inserm, U 975, CRICM, Hôpital de la Pitié-Salpêtrière, F-75013 Paris, France
2 UPMC Université Paris 06, UMR_S975, F-75013, Paris, France
3 CNRS, UMR 7225, F-75013, Paris, France
4 Laboratory of Molecular Neurobiology and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015 Switzerland
5 Université Pierre et Marie Curie-Paris 6, ER4 Modeling in Clinical Research, Paris F-75013 France
6 Elan Pharmaceuticals, 180 Oyster Point Blvd, South San Francisco, California, CA 94080 USA
7 Department of Biostatistics and Medical Informatics, Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux, 47 Boulevard de l'Hôpital, Paris F-75013 France
8 AP-HP, Hôpital de la Salpêtrière, Department of Genetics and Cytogenetics, F-75013 Paris, France
9 Current address: Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne, CH 1008 Switzerland
BMC Neuroscience 2013, 14:135 doi:10.1186/1471-2202-14-135Published: 5 November 2013
Mutations of the gene encoding the major component of Lewy bodies (LB), α-synuclein (α-syn), cause autosomal dominant forms of Parkinson’s disease (PD), whereas loss-of-function mutations of the gene encoding the multifunctional E3 ubiquitin-protein ligase Parkin account for autosomal recessive forms of the disease. Parkin overproduction protects against α-syn-dependent neurodegeneration in various in vitro and in vivo models, but it remains unclear whether this process is affected by Parkin deficiency. We addressed this issue, by carrying out more detailed analyses of transgenic mice overproducing the A30P variant of human α-syn (hA30Pα-syn) and with two, one or no parkin knockout alleles.
Longitudinal behavioral follow-up of these mice indicated that Parkin depletion delayed disease-predictive sensorimotor impairment due to α-syn accumulation, in a dose-dependent fashion. At the end stage of the disease, neuronal deposits containing fibrillar α-syn species phosphorylated at S129 (PS129α-syn) were the predominant neuropathological feature in hA30Pα-syn mice, regardless of their parkin expression. Some of these deposits colocalized with the LB markers ubiquitin and α-syn truncated at D135 (α-synD135), indicating that PS129α-syn is subjected to secondary posttranslational modification (PTM); these features were not significantly affected by parkin dysfunction.
These findings suggest that Parkin deficiency acts as a protective modifier in α-syn-dependent neurodegeneration, without overtly affecting the composition and characteristics of α-syn deposits in end-stage disease.