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L‐DOPA regulates α‐synuclein accumulation in experimental parkinsonism
Author(s) -
Deffains Marc,
Canron MarieHélène,
Teil Margaux,
Li Qin,
Dehay Benjamin,
Bezard Erwan,
Fernagut PierreOlivier
Publication year - 2021
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/nan.12678
Subject(s) - mptp , substantia nigra , putamen , parkinsonism , dopamine , dopaminergic , neuroscience , hippocampal formation , neurotoxin , parkinson's disease , temporal cortex , chemistry , medicine , endocrinology , biology , disease
Aims Widespread accumulation of misfolded α‐synuclein aggregates is a key feature of Parkinson's disease (PD). Although the pattern and extent of α‐synuclein accumulation through PD brains is known, the impact of chronic dopamine‐replacement therapy (the gold‐standard pharmacological treatment of PD) on the fate of α‐synuclein is still unknown. Here, we investigated the distribution and accumulation of α‐synuclein in the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) non‐human primate model of PD and determined the effect of chronic L‐DOPA treatment on MPTP‐induced α‐synuclein pathology. Methods We measured the density of α‐synuclein and tau immuno‐positive neurons in the substantia nigra, putamen, hippocampal CA1 region, temporal cortex and dentate nucleus of control, MPTP and MPTP+L‐DOPA‐treated monkeys. Moreover, we also extracted and quantified Triton‐X (TX) soluble and insoluble α‐synuclein in putamen and hippocampus samples from a separate cohort of control, MPTP and MPTP+L‐DOPA‐treated monkeys. Results MPTP‐induced α‐synuclein accumulation in NHP model of PD was not limited to the substantia nigra but also occurred in the putamen, hippocampal CA1 region and temporal cortex. Tau was increased only in the temporal cortex. Moreover, increased intraneuronal TX insoluble α‐synuclein was truncated, but not in the structural form of Lewy bodies. The MPTP‐induced increase in α‐synuclein levels was abolished in animals having received L‐DOPA in all the brain regions, except in the substantia nigra. Conclusions Dopamine replacement therapy can dramatically ameliorate α‐synuclein pathology in the MPTP NHP model of PD. Therefore, patient's dopaminergic medication should be systematically considered when assessing α‐synuclein as a biomarker for diagnosis, monitoring disease progression and response to disease‐modifying treatments.