FUNCTIONAL, MORPHOLOGICAL, AND TRANSCRIPTOMIC CHARACTERIZATION OF FUSED PURKINJE CELLS IN THE EAE MOUSE MODEL OF MULTIPLE SCLEROSIS

Neurodegenerative diseases are increasing, and cell therapy is one of the most promising treatments for their palliation. Bone marrow-derived cells (BMDCs) migrate into the brain, where they can fuse with neurons, such as Purkinje cells. Although fusion events are rare, their frequency increases in certain pathologies, including multiple sclerosis. In the Experimental Autoimmune Encephalomyelitis (EAE) model of multiple sclerosis, fused cells remain functional and retain two transcriptionally independent nuclei, suggesting that BMDCs could be used as vehicles for delivering therapeutic agents. However, mechanisms underlying fusion and properties of fused cells remain poorly understood.
We transplanted GFP-positive BMDCs to identify fused cells in EAE mice. We optimized timing between transplantation, EAE induction and tissue collection to detect fusion events as soon as possible. Using Patch-Seq technology, we compared individual fused and nearby non-fused Purkinje cells. We recorded cells’ electrophysiological activity, stained them for morphological analysis, and collected their cytoplasm for single-cell RNA sequencing. Finally, we analysed transcriptional activity and the epigenetic state of the two nuclei of fused cells.
Our results showed that the morphology of fused and non-fused cells is quite similar, while action potential frequency is lower in fused cells. Fused Purkinje cells also express typical BMDC genes that are absent in non-fused neurons.
These results will help us understand the nature of cells involved in fusion and its consequences, bringing us closer to using BMDCs as therapy for neurodegenerative diseases.
Funding: MICINN PID2022-140525NB-I00, PID2022-140456NB-I00; JCyL-FEDER SA112P24; Erasmus+ 2023-1-PL01-KA220-HED-000160284; programmes of excellence from JCyL CLU-2023-1-01.