• the Korean Society for Brain and Neural Sciences


Original Article

Exp Neurobiol 2017; 26(6): 321-328

Published online December 31, 2017

© The Korean Society for Brain and Neural Sciences

Cell-to-cell Transmission of Polyglutamine Aggregates in C. elegans

Dong-Kyu Kim1, Kyu-Won Cho1, Woo Jung Ahn1, Dayana Perez-Acuña1,Hyunsu Jeong1,2, He-Jin Lee3,4 and Seung-Jae Lee1*

1Department of Medicine and Biomedical Sciences and Neuroscience Research Institute, Seoul National University College ofMedicine, Seoul 03080, 2Department of Psychology, Seoul National University, Seoul 08826, 3Department of Anatomy, School of Medicine, Konkuk University, Seoul 05029, 4IBST, Konkuk University, Seoul 05029, Korea

Correspondence to: *To whom correspondence should be addressed.
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Received: October 16, 2017; Revised: November 1, 2017; Accepted: December 1, 2017

Huntington disease (HD) is an inherited neurodegenerative disorder characterized by motor and cognitive dysfunction caused by expansion of polyglutamine (polyQ) repeat in exon 1 of huntingtin (HTT). In patients, the number of glutamine residues in polyQ tracts are over 35, and it is correlated with age of onset, severity, and disease progression. Expansion of polyQ increases the propensity for HTT protein aggregation, process known to be implicated in neurodegeneration. These pathological aggregates can be transmitted from neuron to another neuron, and this process may explain the pathological spreading of polyQ aggregates. Here, we developed an in vivo model for studying transmission of polyQ aggregates in a highly quantitative manner in real time. HTT exon 1 with expanded polyQ was fused with either N-terminal or C-terminal fragments of Venus fluorescence protein and expressed in pharyngeal muscles and associated neurons, respectively, of C. elegans. Transmission of polyQ proteins was detected using bimolecular fluorescence complementation (BiFC). Mutant polyQ (Q97) was transmitted much more efficiently than wild type polyQ (Q25) and forms numerous inclusion bodies as well. The transmission of Q97 was gradually increased with aging of animal. The animals with polyQ transmission exhibited degenerative phenotypes, such as nerve degeneration, impaired pharyngeal pumping behavior, and reduced life span. The C. elegans model presented here would be a useful in vivo model system for the study of polyQ aggregate propagation and might be applied to the screening of genetic and chemical modifiers of the propagation.

Graphical Abstract

Keywords: Aging, Bimolecular Fluorescence Complementation, C. elegans, Huntington disease, Huntingtin, Protein aggregation