Novel C. elegans models of Lewy body disease reveal pathological protein interactions and widespread miRNA dysregulation

Lewy body diseases (LBD) comprise a group of complex neurodegenerative conditions originating from accumulation of misfolded alpha-synuclein (α-syn) in the form of Lewy bodies. LBD pathologies are characterized by α-syn deposition in association with other proteins such as Amyloid β (Aβ), Tau, and TAR-DNA-binding protein. To investigate the complex interactions of these proteins, we constructed 2 novel transgenic overexpressing (OE) C. elegans strains (α-syn_A53T;Tau_pro-agg (OE) and α-syn_A53T;Aβ1-42;Tau_pro-agg (OE)) and compared them with previously established Parkinson's, Alzheimer's, and Lewy Body Dementia disease models. The LBD models presented here demonstrate impairments including uncoordinated movement, egg-laying deficits, altered serotonergic and cholinergic signaling, memory and posture deficits, as well as dopaminergic neuron damage and loss. Expression levels of total and prone to aggregation α-syn protein were increased in α-syn_A53T;Aβ_1-42 but decreased in α-syn_A53T;Tau_pro-agg animals when compared to α-syn_A53T animals suggesting protein interactions. These alterations were also observed at the mRNA level suggesting a pre-transcriptional mechanism. miRNA-seq revealed that cel-miR-1018 was upregulated in LBD models α-syn_A53T, α-syn_A53T;Aβ_1-42, and α-syn_A53T;Tau_pro-agg compared with WT. cel-miR-58c was upregulated in α-syn_A53T;Tau_pro-agg but downregulated in α-syn_A53T and α-syn_A53T;Aβ_1-42 compared with WT. cel-miR-41-3p and cel-miR-355-5p were significantly downregulated in 3 LBD models. Our results obtained in a model organism provide evidence of interactions between different pathological proteins and alterations in specific miRNAs that may further exacerbate or ameliorate LBD pathology.