A behavior-based drug screening system using a Caenorhabditis elegans model of motor neuron disease

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons, for which there is no effective treatment. Previously, we generated a Caenorhabditis elegans model of ALS, in which the expression of dnc-1 , the homologous gene of human dynactin-1 , is knocked down (KD) specifically in motor neurons. This dnc-1 KD model showed progressive motor defects together with axonal and neuronal degeneration, as observed in ALS patients. In the present study, we established a behavior-based, automated, and quantitative drug screening system using this dnc-1 KD model together with Multi-Worm Tracker (MWT), and tested whether 38 candidate neuroprotective compounds could improve the mobility of the dnc-1 KD animals. We found that 12 compounds, including riluzole, which is an approved medication for ALS patients, ameliorated the phenotype of the dnc-1 KD animals. Nifedipine, a calcium channel blocker, most robustly ameliorated the motor deficits as well as axonal degeneration of dnc-1 KD animals. Nifedipine also ameliorated the motor defects of other motor neuronal degeneration models of C . elegans , including dnc-1 mutants and human TAR DNA-binding protein of 43 kDa overexpressing worms. Our results indicate that dnc-1 KD in C . elegans is a useful model for the screening of drugs against motor neuron degeneration, and that MWT is a powerful tool for the behavior-based screening of drugs.

Lighting Up Ca2+ Dynamics in Animal Models

“…The approach is particularly relevant since it provides partial downregulation of the expression of proteins whose complete loss would result in early lethality [197,207]. Pharmacological high throughput screenings can also be performed in C. elegans models of neurodegenerative diseases to search for small molecules as possible therapeutic treatments [208,209].…”

The Role of Ca2+ Signaling in Aging and Neurodegeneration: Insights from Caenorhabditis elegans Models

“…Interestingly, L-type Ca 2+ channel agonists FPL 64176 or Bay K 8644 had been shown before to protect the same zebrafish amyotrophic lateral sclerosis model against neuromuscular dysfunction [106]. In contrast, a screening of 38 neuroprotective compounds was recently made in a C. elegans model of amyotrophic lateral sclerosis, with null mutation of dnc-1, the homologous of human dynactin-1, and the L-type Ca 2+ channel blocker nifedipine greatly improved motor deficits, as well as axonal degeneration [107]. Although the mechanism is probably complex, these results clearly indicate that Ca 2+ signaling plays a very important role in the pathogenic mechanism of this disease.…”

“…High-throughput drug screening technologies using C. elegans to search for compounds that modify aging or neurodegeneration are increasingly being used [7,8,105,107]. Some of them have been made in liquid media or in microwell plates, but more recently, microfluidic devices have emerged as powerful tools for these large-scale screenings [112].…”

Exploiting flow cytometry for the unbiased quantification of protein inclusions inCaenorhabditis elegans

“…Since the formation of insoluble proteinaceous inclusion bodies is a common feature among proteinopathies, it is thought that preventing this process is likely to be a beneficial strategy for halting the progression of these diseases (Bose & Cho 2017). Thus, multiple studies have focused on high-throughput screening for genetic or chemical modulators of protein aggregation in various model systems (Cockburn et al 2011; Ikenaka et al 2019; Sarkany et al 2019; Silva et al 2011). These high-throughput screens often rely on having a quantifiable readout of aggregation dynamics that can be determined rapidly and at low-cost.…”

“…Consequently, they have been investigated extensively in forward and reverse genetic studies to identify genes that modulate biochemical processes including those involved in protein aggregation and neurodegeneration (Kraemer et al 2006; Nollen et al 2004; van Ham et al 2008). They are also highly amenable to screens of pharmacological compounds and are often used as an initial model system for potential therapeutics before conducting rodent-based studies (Chen et al 2015; Ikenaka et al 2019). A common approach for studying neurodegenerative diseases in C. elegans is to utilise strains that express specific disease-associated, aggregation-prone proteins fused with a fluorescent tag for visualisation within worms.…”