Benzimidazoles cause lethality by inhibiting the function of Caenorhabditis elegans neuronal beta-tubulin

Abstract

Parasitic nematode infections cause an enormous global burden to both human and livestock populations. Resistance to the limited arsenal of anthelmintic drugs used to combat these infections is widespread, including resistance to benzimidazole (BZ) compounds commonly found in livestock parasites. Previous studies using the free-living nematode Caenorhabditis elegans to model parasitic nematode resistance have shown that loss-of-function mutations in the beta-tubulin gene ben-1 confer resistance to BZ drugs. However, the mechanism of resistance and the tissue-specific susceptibility are not well known in any nematode species. To identify in which tissue(s) ben-1 function underlies BZ susceptibility, transgenic strains that express ben-1 in different tissues, including hypodermis, muscles, neurons, intestine, and ubiquitous expression were generated. High-throughput fitness assays were performed to measure and compare the quantitative responses to BZ compounds among different transgenic lines. Significant BZ susceptibility was observed in animals expressing ben-1 in neurons, comparable to expression using the ben-1 promoter. This result suggests that ben-1 function in neurons underlies susceptibility to BZ. Subsetting neuronal expression of ben-1 based on neurotransmitter system further restricted ben-1 function in cholinergic neurons to cause BZ susceptibility. These results better inform our current understanding of the cellular mode of action of BZ and also suggest additional treatments that might potentiate the effects of BZs.

Screening of the Pandemic Response Box identifies anti-microsporidia compounds

“…Benzimidazoles are known to inhibit C. elegans and natural resistance to these compounds has arisen through genetic variation in betatubulin [57,58]. Host toxicity has been shown to be mediated through inhibition of neuronal betatubulin [59]. Carbendazim, fenbendazole and oxfendazole are present in the PRB, however, in our preliminary screening, we did not find that these compounds improved progeny production in the presence of N. parisii.…”

Quantifying the fitness effects of resistance alleles with and without anthelmintic selection pressure usingCaenorhabditis elegans

“…To date, our understanding of the MoR and tissue-specific susceptibility for most anthelmintic drugs across nematode species is not well known. Previous research has shown that ben-1 is highly expressed in cholinergic neurons, which causes BZ susceptibility [42]. However, analogous experiments are imperative to ascertain in which tissues GluCl subunit genes underlie ivermectin susceptibility.…”

“…With its ease of growth, outstanding genetic tractability, and molecular toolkits, the free-living nematode Caenorhabditis elegans has contributed to the identification and characterization of the MoA and MoR of all major anthelmintic drug classes [27][28][29][30][31][32][33][34]. Additionally, wild C. elegans strains from the Caenorhabditis Natural Diversity Resource (CaeNDR) [35] have been used to explore anthelmintic resistance in natural populations and to uncover novel MoR [30,[35][36][37][38][39][40][41][42].…”

“…Both the laboratory-adapted strain, N2, and C. elegans wild strains have facilitated the identification and characterization of the beta-tubulin gene ben-1 as the primary target of albendazole and other BZs [28,29,39,42,43]. Loss-of-function mutations in ben-1 have been identified in C. elegans strains resistant to BZs [44].…”

Quantifying the fitness effects of resistance alleles with and without anthelmintic selection pressure using Caenorhabditis elegans

“…With its ease of growth, outstanding genetic tractability, and molecular toolkits, the free-living nematode Caenorhabditis elegans has contributed to the identification and characterization of the Mode of Action (MoA) and MoR of all major anthelmintic drug classes [33][34][35][36][37][38][39][40]. Additionally, wild C. elegans strains from the Caenorhabditis Natural Diversity Resource (CaeNDR) [41] have been used to explore anthelmintic resistance in natural populations and to uncover novel MoR [36,[41][42][43][44][45][46][47][48].…”