Biology subjects

Di Fabrizio, M.

Publications and source records attributed to Di Fabrizio, M..

3 recordsLinked to original sources

bioRxiv2025

Multiscale analysis of myelin alterations in skin biopsies from synucleinopathies.

Loss of myelin and demyelination play a role in the pathophysiology of Parkinsons disease (PD) and related neurodegenerative diseases, but little is known about the ultrastructure of the myelin-axon unit in the peripheral nervous system of subjects diseased with synucleinopathies. We here present an analysis of the myelin ultrastructure and the myelin protein abundance that characterize myelinated axons of nerve fiber bundles in cervical skin biopsies of 45 pathologically confirmed PD, DLB, MSA and non-neurological control donors. We calculated a myelin damage score and classified over 1100 myelin sheaths by looking at myelin fragmentation and swellings with correlative light and electron microscopy. We found a higher load of myelin damage in the PD compared to MSA and control groups. Quantification with ELISA did not reveal any differences in myelin protein zero (MPZ) concentrations in skin tissue homogenates between synucleinopathies. The observed structural abnormalities in the myelin sheaths may help to discriminate among subjects with synucleinopathies and control subjects and to understand the involvement of the peripheral innervation in the diseases. Our multiscale analysis of peripheral nerves highlights their potential as future biomarkers for the detection and differentiation of synuclein diseases.

neuroscience↗

bioRxiv2024

Ultrastructural diversity of alpha-Synuclein pathology in the post-mortem brain of Parkinson patients: implications for Lewy Body formation

Lewy bodies, the defining pathological feature of Parkinsons disease, are intraneuronal inclusions enriched in aggregated alpha-synuclein (Syn). We used correlative light and electron microscopy to selectively investigate phosphorylated Syn (SynpS129)-positive inclusions in the substantia nigra of end-stage postmortem Parkinsons disease brain. Here we show that somatic SynpS129 inclusions in nigral dopaminergic neurons are consistently fibrillar, whereas the membranous-type inclusions are restricted to neuritic processes. These neuritic inclusions displayed marked ultrastructural heterogeneity, ranging from predominantly membranous to mixed membranous-fibrillar forms. The selective targeting of defined inclusions enabled detailed structural characterization of Lewy pathology, rather than quantitative or disease-stage comparisons. Our findings highlight clear ultrastructural differences between somatic and neuritic SynpS129 pathology and demonstrate the structural complexity and heterogeneity of Lewy pathology in human Parkinsons disease brain.

neuroscience↗

bioRxiv2024

A versatile correlative light and electron microscopy protocol for human brain and other biological models

Correlative light and electron microscopy (CLEM) combines light microscopy, for identifying a target via genetic labels, dyes, antibodies, and morphological features, with electron microscopy, for analyzing high-resolution subcellular ultrastructures. Here, we describe the step-by-step instructions to perform a CLEM experiment, optimized for the investigation of ultrastructural features in human brain tissue. The procedure is carried out at room-temperature and can be also adapted to other human and animal tissue samples. The procedure requires 8-days to complete and includes the stages of sample fixation for optimal ultrastructural preservation, immunofluorescence staining, image acquisition, multi-modal image correlation, and is executable within standard EM laboratories. Serving as a critical tool for characterizing human tissue and disease models, room-temperature CLEM facilitates the identification and quantification of subcellular morphological features across brain regions. Key pointsO_LIThe protocol for correlative light and electron microscopy (CLEM) is optimized for analyzing chemically fixed human brain tissues. It focuses on maintaining the integrity of ultrastructural features, thereby minimizing artifacts and structural alterations. C_LIO_LIExamining brain tissues at the ultrastructural level can provide an unprecedented amount of detail which may help advance our understanding of the mechanisms underlying neurodegenerative disorders. C_LI

neuroscience↗