Cerebral dopamine neurotrophic factor reduces α-synuclein aggregation and propagation and alleviates behavioral alterations in vivo

Katrina Albert,Yraima Cordeiro,Kelvin C Luk,Aastha Singh,Andrii Domanskyi,Mikko Airavaara,Fernando L Palhano,Xu Yan,Merja H Voutilainen,Liana Shvachiy,Ave Eesmaa,Tiago F Outeiro,Anne Panhelainen,Marcius S Almeida,Henri J Huttunen,Piotr Chmielarz,Débora Foguel ,Gabriela Rocha De Araújo ,Märt Saarma ,Diana Pelizzari Raymundo

doi:10.1016/j.ymthe.2021.04.035

Abstract

A molecular hallmark in Parkinson’s disease (PD) pathogenesis are α-synuclein aggregates. Cerebral dopamine neurotrophic factor (CDNF) is an atypical growth factor that is mostly resident in the endoplasmic reticulum but exerts its effects both intracellularly and extracellularly. One of the beneficial effects of CDNF can be protecting neurons from the toxic effects of α-synuclein. Here, we investigated the effects of CDNF on α-synuclein aggregation in vitro and in vivo. We found that CDNF directly interacts with α-synuclein with a KD = 23 ± 6 nM and reduces its auto-association. Using nuclear magnetic resonance (NMR) spectroscopy, we identified interaction sites on the CDNF protein. Remarkably, CDNF reduces the neuronal internalization of α-synuclein fibrils and induces the formation of insoluble phosphorylated α-synuclein inclusions. Intra-striatal CDNF administration alleviates motor deficits in rodents challenged with α-synuclein fibrils, though it did not reduce the number of phosphorylated α-synuclein inclusions in the substantia nigra. CDNF’s beneficial effects on rodent behavior appear not to be related to the number of inclusions formed in the current context, and further study of its effects on the aggregation mechanism in vivo are needed. Nonetheless, the interaction of CDNF with α-synuclein, modifying its aggregation, spreading, and associated behavioral alterations, provides novel insights into the potential of CDNF as a therapeutic strategy in PD and other synucleinopathies.

Highlights

Parkinson’s disease (PD) is a neurodegenerative disorder known for typical motor symptoms such as tremor, rigidity, and slowness of movement caused by decline in dopamine neurotransmission in the striatum, a result of loss of dopaminergic neurons in the substantia nigra pars compacta.[1,2] The major pathological hallmark seen in postmortem examination of the brains of PD patients is the presence of Lewy bodies and Lewy neurites,[3] neuronal structures rich in lipid and proteins
We used a protein-fragment complementation assay (PCA) based on the split humanized Gaussia princeps luciferase (GLuc) system[22] C-terminally fused to a-synuclein. When these a-synuclein-GLuc PCA reporters are co-expressed, the bioluminescence serves as a sensitive readout of a-synuclein dimer/oligomer levels.[23]
When increasing levels of human Cerebral dopamine neurotrophic factor (CDNF) were co-transfected to Neuro2A cells with the a-synuclein-GLuc PCA reporters, there was a notable, gene-dose-dependent reduction in a-synuclein oligomer levels that was not observed with controls located to lysosomes, secretory pathway, and cytosol (Figure 1B)

Summary

Introduction

Parkinson’s disease (PD) is a neurodegenerative disorder known for typical motor symptoms such as tremor, rigidity, and slowness of movement caused by decline in dopamine neurotransmission in the striatum, a result of loss of dopaminergic neurons in the substantia nigra pars compacta.[1,2] The major pathological hallmark seen in postmortem examination of the brains of PD patients is the presence of Lewy bodies and Lewy neurites,[3] neuronal structures rich in lipid and proteins.

Methods

Results

Conclusion