Targeted α-Synuclein mRNA Degradation by PMO-Based RNA-Degrading Chimeras.

Area of Science:

• Neuroscience
• Molecular Biology
• Drug Discovery

Background:

• Alpha-synucleinopathies are neurodegenerative diseases linked to the abnormal accumulation of alpha-synuclein (αSyn).
• Directly targeting αSyn protein is challenging due to its structure and delivery issues.
• Targeting the SNCA transcript, which encodes αSyn, is an emerging therapeutic strategy.

Purpose of the Study:

• To develop and evaluate phosphorodiamidate morpholino oligonucleotide (PMO)-based RNA-degrading chimeras (RDCs) for degrading SNCA mRNA.
• To assess the efficacy of RDCs in reducing αSyn mRNA and protein levels in cellular and animal models.
• To determine if RDC-mediated αSyn reduction can prevent αSyn aggregation and neurotoxicity.

Main Methods:

• Development of PMO-based RDCs targeting the 5' untranslated region of SNCA mRNA.
• Evaluation of RDC-mediated RNA degradation via RNase L recruitment in HEK293T cells.
• Testing in primary cortical neurons and human induced pluripotent stem cell-derived neurons.
• Assessment of neuroprotection against αSyn fibril-induced toxicity and prion-like seeding.
• In vivo validation in humanized SNCA mice.

Main Results:

• Optimized RDC, 4-D1, effectively reduced SNCA mRNA and αSyn protein in a dose-dependent and RNase L-dependent manner.
• 4-D1 demonstrated efficacy in reducing αSyn levels in both mouse and human neuronal models.
• Treatment with 4-D1 prevented αSyn fibril-induced seeding and protected neurons from cytotoxicity.
• In vivo studies confirmed 4-D1's ability to reduce αSyn mRNA expression in mice.

Conclusions:

• PMO-based RDCs are a viable strategy for degrading SNCA mRNA and reducing αSyn.
• The developed RDC, 4-D1, shows therapeutic potential for treating alpha-synucleinopathies.
• This approach offers a promising avenue for developing new treatments for these devastating neurodegenerative diseases.