Adgrg6 (Gpr126) is an adhesion class G protein-coupled receptor with a conserved role in myelination of the peripheral nervous system. In the zebrafish, mutation of adgrg6 also results in defects in the inner ear: otic tissue fails to down-regulate versican gene expression and morphogenesis is disrupted. We have designed a whole-animal screen that tests for rescue of both up- and down-regulated gene expression in mutant embryos, together with analysis of weak and strong alleles. From a screen of 3120 structurally diverse compounds, we have identified 68 that reduce versican b expression in the adgrg6 mutant ear, 41 of which also restore myelin basic protein gene expression in Schwann cells of mutant embryos. Nineteen compounds unable to rescue a strong adgrg6 allele provide candidates for molecules that may interact directly with the Adgrg6 receptor. Our pipeline provides a powerful approach for identifying compounds that modulate GPCR activity, with potential impact for future drug design.
Summary Adhesion GPCRs are important regulators of conserved developmental processes and represent an untapped pool of potential targets for drug discovery. The adhesion GPCR Adgrg6 (Gpr126) has critical developmental roles in Schwann cell maturation and inner ear morphogenesis in the zebrafish embryo. Mutations in the human ADGRG6 gene can result in severe deficits in peripheral myelination, and variants have been associated with many other disease conditions. Here, we review work on the zebrafish Adgrg6 signaling pathway and its potential as a disease model. Recent advances have been made in the analysis of the structure of the Adgrg6 receptor, demonstrating alternative structural conformations and the presence of a conserved calcium‐binding site within the CUB domain of the extracellular region that is critical for receptor function. Homozygous zebrafish adgrg6 hypomorphic mutants have been used successfully as a whole‐animal screening platform, identifying candidate molecules that can influence signaling activity and rescue mutant phenotypes. These compounds offer promise for further development as small molecule modulators of Adgrg6 pathway activity.
Adhesion G protein‐coupled receptors (GPCRs) are an underrepresented class of GPCRs in drug discovery. We previously developed an in vivo drug screening pipeline to identify compounds with agonist activity for Adgrg6 (Gpr126), an adhesion GPCR required for myelination of the peripheral nervous system in vertebrates. The screening assay tests for rescue of an ear defect found in adgrg6tb233c−/− hypomorphic homozygous mutant zebrafish, using the expression of versican b (vcanb) mRNA as an easily identifiable phenotype. In the current study, we used the same assay to screen a commercially available library of 1280 diverse bioactive compounds (Sigma LOPAC). Comparison with published hits from two partially overlapping compound collections (Spectrum, Tocris) confirms that the screening assay is robust and reproducible. Using a modified counter screen for myelin basic protein (mbp) gene expression, we have identified 17 LOPAC compounds that can rescue both inner ear and myelination defects in adgrg6tb233c−/− hypomorphic mutants, three of which (ebastine, S‐methylisothiourea hemisulfate, and thapsigargin) are new hits. A further 25 LOPAC hit compounds were effective at rescuing the otic vcanb expression but not mbp. Together, these and previously identified hits provide a wealth of starting material for the development of novel and specific pharmacological modulators of Adgrg6 receptor activity.
23Adgrg6 (Gpr126) is an adhesion class G protein-coupled receptor with a conserved role in 24 myelination of the peripheral nervous system. In the zebrafish, mutation of adgrg6 also 25 results in defects in the inner ear: otic tissue fails to down-regulate versican-gene expression 26 and morphogenesis is disrupted. We have designed a whole-animal screen that tests for 27 rescue of both up-and down-regulated gene expression in mutant embryos, together with 28 analysis of weak and strong alleles. From a screen of 3120 structurally diverse compounds, 29 we have identified 68 that reduce versican-b expression in the adgrg6 mutant ear, 41 of 30 which also restore myelin basic protein gene expression in Schwann cells of mutant 31 embryos. Nineteen compounds unable to rescue a strong adgrg6 allele provide candidates 32 for molecules that interact directly with the Adgrg6 receptor. Our pipeline provides a 33 powerful approach for identifying compounds that modulate GPCR activity, with potential 34 impact for future drug design. 35 36 3
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.