Presenter of 1 Presentation
NOT JUST LEWY BODIES: A NANOSCALE VIEW OF PARKINSON'S PATHOLOGY IN POST-MORTEM HUMAN BRAIN
Abstract
Aims
Parkinson’s disease (PD) is characterised by the presence of Lewy bodies - large, fibrillar intra-neuronal accumulations of alpha-synuclein (aSyn). It is currently thought aSyn monomers misfold and oligomerize, forming amyloid fibrils which accumulate into these fibrillar Lewy bodies. However, using electron microscopy, we have recently demonstrated that non-hallmark aSyn pathology in post-mortem human brain consists of accumulated membranes, cellular vesicles and organelles in which fibrils were not always detected. It is unknown whether these membranous aSyn accumulations represent an earlier stage in the formation of fibrillar Lewy bodies, or if they arise through a separate mechanism. In this study we developed a new correlative light and electron microscopy pipeline to investigate the ultrastructure of intra-neuronal aSyn accumulation in brain sections from PD patients. The incorporation of confocal light microscopy allowed us to efficiently target specific morphologies of aSyn accumulation thought to represent earlier stages of Lewy body formation.
Methods
We used correlative confocal light and electron microscopy to localise aSyn pathology in chemically fixed post-mortem human brain of five PD patients. Free-floating brain sections were immunolabelled and imaged using confocal laser scanning microscopy. The same sections were then processed for electron microscopy using en bloc staining and resin-embedding for ultrastructural investigation.
Results
We localized and imaged over 280 examples of intra-neuronal aSyn accumulation, showing the ultrastructure of different morphologies of aSyn pathology thought to represent earlier stages of Lewy body formation.
Conclusions
Our data provides key insight into the mechanisms behind accumulation of aSyn and the formation of Lewy bodies in human PD brain.