Abundance of Synaptic Vesicle-Related Proteins in Alpha-Synuclein-Containing Protein Inclusions Suggests a Targeted Formation Mechanism
Proteinaceous α-synuclein-containing inclusions are found in affected brain regions in patients with Parkinson’s disease (PD), Dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). These appear in neurons as Lewy bodies in both PD and DLB and as glial cytoplasmic inclusions (GCIs) in oligodendrocytes in MSA. The role they play in the pathology of the diseases is unknown, and relatively little is still known about their composition. By purifying the inclusions from the surrounding tissue and comprehensively analysing their protein composition, vital clues to the formation mechanism and role in the disease process may be found. In this study, Lewy bodies were purified from postmortem brain tissue from DLB cases (n = 2) and GCIs were purified from MSA cases (n = 5) using a recently improved purification method, and the purified inclusions were analysed by mass spectrometry. Twenty-one percent of the proteins found consistently in the GCIs and LBs were synaptic-vesicle related. Identified proteins included those associated with exosomes (CD9), clathrin-mediated endocytosis (clathrin, AP-2 complex, dynamin), retrograde transport (dynein, dynactin, spectrin) and synaptic vesicle fusion (synaptosomal-associated protein 25, vesicle-associated membrane protein 2, syntaxin-1). This suggests that the misfolded or excess α-synuclein may be targeted to inclusions via vesicle-mediated transport, which also explains the presence of the neuronal protein α-synuclein within GCIs.
KeywordsLewy body Glial cytoplasmic inclusion Parkinson’s disease Multiple system atrophy Vesicle trafficking Mass spectrometry
We would like to acknowledge Dr. Weiping Gai for the anti-α-synuclein antibody, Ms. Fariba Chegini for her assistance with immunofluoresence and the South Australian Brain Bank for their support.
This study is financially supported by the Flinders Medical Centre Research Foundation, South Australia.
- Gai WP, Power JH, Blumbergs PC, Culvenor JG, Jensen PH (1999) Alpha-synuclein immunoisolation of glial inclusions from multiple system atrophy brain tissue reveals multiprotein components. J Neurochem 73:2093–2100Google Scholar
- Inoue M, Yagishita S, Ryo M, Hasegawa K, Amano N, Matsushita M (1997) The distribution and dynamic density of oligodendroglial cytoplasmic inclusions (GCIs) in multiple system atrophy: a correlation between the density of GCIs and the degree of involvement of striatonigral and olivopontocerebellar systems. Acta Neuropathol 93:585–591CrossRefGoogle Scholar
- Iwatsubo T, Yamaguchi H, Fujimuro M, Yokosawa H, Ihara Y, Trojanowski JQ, Lee VM (1996) Purification and characterization of Lewy bodies from the brains of patients with diffuse Lewy body disease. Am J Pathol 148:1517–1529Google Scholar
- Keating DJ (2008) Mitochondrial dysfunction, oxidative stress, regulation of exocytosis and their relevance to neurodegenerative diseases. J Neurochem 104:298–305Google Scholar
- Lindersson E, Lundvig D, Petersen C, Madsen P, Nyengaard JR, Højrup P, Moos T, Otzen D, Gai WP, Blumbergs PC, Jensen PH (2005) p25alpha Stimulates alpha-synuclein aggregation and is co-localized with aggregated alpha-synuclein in alpha-synucleinopathies. J Biol Chem 280:5703–5715CrossRefGoogle Scholar
- Link AJ, LaBaer J (2009) Proteomics: a Cold Spring Harbor laboratory course manual. Cold Spring Harbor laboratory press, Cold Spring HarborGoogle Scholar
- McKeith I, Mintzer J, Aarsland D, Burn D, Chiu H, Cohen-Mansfield J, Dickson D, Dubois B, Duda JE, Feldman H, Gauthier S, Halliday G, Lawlor B, Lippa C, Lopez OL, Carlos Machado J, O'Brien J, Playfer J, Reid W, International Psychogeriatric Association Expert Meeting on DLB (2004) Dementia with Lewy bodies. Lancet Neurol 3:19–28CrossRefGoogle Scholar
- Shahmoradian SH, Genoud C, Graff-Meyer A, Hench J, Moors T, Schweighauser G, Wang J, Goldie KN, Suetterlin R, Castano-Diez D, Perez-Navarro P, Huisman E, Ipsen S, Ingrassia A, De Gier Y, Rozemuller AJ, Da Paepe A, Erny J, Staempfli A, Hoernschemeyer J, Grosserueschkamp F, Niedieker D, El-Mashtoly S, Quadri M, Van WF, Bonifati V, Gerwert K, Bohrmann B, Frank A, Britschgi M, Stahlberg H, Berg VD, Lauer ME (2017) Lewy pathology in Parkinson’s disease consists of a crowded organellar membranous medley. Cold Spring Harbor Laboratory Press, Cold Spring HarborGoogle Scholar
- Vanacore N, Bonifati V, Fabbrini G, Colosimo C, de Michele G, Marconi R, Nicholl D, Locuratolo N, Talarico G, Romano S, Stocchi F, Bonuccelli U, de Mari M, Vieregge P, Meco G, European Study Group on Atypical Parkinsonism (ESGAP) (2001) Epidemiology of multiple system atrophy. ESGAP Consortium. European Study Group on Atypical Parkinsonisms. Neurol Sci 22:97–99CrossRefGoogle Scholar