Gaihre, Y. | bioRxiv Science

bioRxiv2026

Potential nematicides identified through targeted in vivo screening of a 5-HT-gated chloride channel, MOD-1

New approaches to mitigate the reduction of crop yields by plant parasitic nematodes are needed in the face of increasing concerns of the impact of nematicides on precious ecosystems. One approach is to target receptors in the parasitic nematode that are vital for their survival that less widely expressed in non-target organisms. Nematodes express a phylogenetically restricted 5-HT-gated chloride channel, MOD-1, activation of which causes paralysis in Caenorhabditis elegans. We show that MOD-1 is expressed in the motor nervous system of the plant parasitic nematode Globodera pallida and its functional characterisation is validated by 5-HT activation when reconstituted in Xenopus laevis oocytes. To evaluate MOD-1 as a nematicide target we utilised a previously described platform called PhaGeM4 for PharmacoGenetic targeting of M4 neurone in which MOD-1 is expressed in transgenic C. elegans and nematode development in the face of MOD-1 chemical modulation is tracked. We screened Pathogen Box, a chemical library of 400 diverse drug-like molecules, using PhaGeM4. This identified 10 putative hits for C. elegans MOD-1. These hits were pursued through a sequential, iterative pipeline encompassing mod-1 dependent C. elegans motility and G.pallida motility assays in combination with pharmacological interrogation of G. pallida mod-1 in PhaGeM4. This approach highlights 3 compounds with a mod-1 dependent action (quipazine, our benchmark compound; MMV687251, a vancomycin-like compound; MMV688774, an antifungal with common name posaconazole) and one compound that acts through an undetermined target (MMV002816, also known as the antifilarial drug, diethylcarbamazine). Each of these compounds had a significant inhibitory effect on G. pallida J2 root invasion. Overall, this lends confidence that the PhaGeM4 screening platform can delivery new chemical leads for crop protection and highlights four new chemistries of interest. More generally, this approach could be applied to other ligand-gated ion channels of interest as targets.

pharmacology and toxicology↗

bioRxiv2025

Binding Affinity Ranking at the Molecular Initiating Event (BARMIE): An open-source computational pipeline for ecological hazard ranking of endocrine disrupting chemicals.

A challenge in ecological risk assessment is identifying the chemicals that pose the greatest threat and determining which species are most vulnerable to them. To help address this, this study has developed an in-silico open-source tool called BARMIE (Binding Affinity Ranking at the Molecular Initiating Event) to rapidly predict the chemical binding affinity of steroid receptor proteins to synthetic steroids to identify potentially vulnerable species and chemicals of concern. BARMIE was used to screen 163 teleost fish glucocorticoid receptors (GRs) for binding to the natural ligand cortisol and to 10 synthetic glucocorticoid drugs (GCs) designed to interact within the ligand-binding pocket (LBP) of GRs. BARMIE identified species from the superorder Protacanthopterygii with high-affinity GRs to synthetic GCs (e.g. vulnerable species). . BARMIE was also used to screen binding profiles of compounds in the Medicine for Malaria Venture Global Health Priority Box to rainbow trout GRs (rtGR1 and rtGR2). Of the 178 compounds, 24 and 36 bind within the LBP of rtGR1 and rtGR2, respectively. For 30 of these compounds, transactivation activity was assessed at 1{micro}M in the presence or absence of 1{micro}M cortisol and confirmed 2 compounds with agonistic properties (e.g. chemicals of concern) that would require further in vitro and/or in vivo studies to assess the environmental risk. BARMIE can rapidly generate predicted binding affinities for 100s of species and chemicals as a first screen in environmental risk assessment to provide information on which substances to prioritise in downstream tests.

pharmacology and toxicology↗