Lewy pathology in Parkinson's disease consists of a crowded organellar membranous medley

Parkinsonu0027s disease, the most common age-related movement disorder, is a progressive neurodegenerative disease with unclear etiology. Key neuropathological hallmarks are Lewy bodies and Lewy neurites, which are neuronal inclusions that are immunopositive for the protein alpha-synuclein. In-depth ultrastructural analysis of Lewy pathology is key to understanding pathogenesis and progression of the disease. Using correlative light and electron microscopy on postmortem brain tissue of Parkinsonu0027s patients, we discovered a crowded membranous medley of vesicular structures, dysmorphic mitochondria and disrupted cytoskeletal elements in Lewy bodies and Lewy neurites, rather than the widely expected proteinacious filaments. The collapse and crowding of central organellar components was confirmed by stimulated emission-depletion microscopy, and chemical and optical imaging. A high lipid content was confirmed by lipidomics. The findings indicate ill-defined subcellular protein-lipid compartmentalization and point toward impaired organellar trafficking as a key driver of pathogenesis in Parkinsonu0027s disease.