Objective: The objective of these studies is to develop a tissue engineered nigrostriatal system involving human dopaminergic and striatal cells to recapitulate many of the components of the nigrostriatal system for the study of pathophysiological mechanisms involved in the deposition of alpha-synuclein (a-syn), the role of axonal dystrophy and cell-to-cell transmission of a-syn.

Background: Parkinson’s disease (PD) motor deficits are caused by the loss of dopaminergic cells predominately located in the substantia nigra pars compacta and their long-projecting axonal tracts that innervate the striatum. Much is yet to be learned about the mechanisms of pathophysiology in PD including the role of a-syn aggregation, the relationship to neuritic dystrophy, and the role of cell-to-cell transmission of fibrillar a-syn.

Method: We have developed an in vitro model referred to as a tissue engineered nigrostriatal pathway (TE-NSP) using human induced dopaminergic neurons and striatal neurons, connected by long-projecting axonal pathways. TE-NSPs are built using a tubular hydrogel microcolumn (>1.5 cm long) comprised of an outer methacrylated hyaluronic acid (MeHA) encasement and an extracellular matrix (ECM) cocktail of collagen type I and laminin (1 mg/mL each) in the lumen. Cultured and aggregated dopaminergic and striatal neurons are seeded into either end of the micro-columns, with implantation conducted both sequentially, and simultaneously.

Results: Human-derived TE-NSPs were developed with bundled axonal tracts (> 12mm) from aggregated dopaminergic neurons projecting towards striatal neurons showing axonal-dendritic integration. We injected α-syn pre-formed fibrils (4 µM/mL) within the dopaminergic neuronal aggregates and show widespread uptake of a-syn, and neuronal survival (90-95% viability of both cell types) for at least 8 weeks. Immunocytochemistry confirmed α-syn aggregates within dopaminergic neurons and their axons which was associated with a down-regulation of tyrosine hydroxylase expression. In addition, a-syn aggregation was also demonstrated within the aggregated striatal neurons, confirming our system as a model for the axonal transport and cell-to-cell transmission of a-syn.

Conclusion: We have developed a tissue engineered construct that better represents some of the features of the nigrostriatal system in humans for investigating pathophysiology and therapeutic development.

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/a-human-tissue-engineered-nigrostriatal-system-as-a-testbed-for-understanding-pd-pathophysiology-and-therapeutic-development/