A prevalent feature of is a life-long and potentially lethal infection that is due to the nematode parasite's ability to autoinfect and, thereby, self-replicate within its host. Here, we investigated the role of the parasite's nuclear receptor, DAF-12, in governing infection. We identified Δ7-DA as the endogenous DAF-12 ligand and elucidated the hormone's biosynthetic pathway. Genetic loss of function of the ligand's rate-limiting enzyme demonstrated that Δ7-DA synthesis is necessary for parasite reproduction, whereas its absence is required for the development of infectious larvae. Availability of the ligand permits DAF-12 to function as an on/off switch governing autoinfection, making it vulnerable to therapeutic intervention. In a preclinical model of hyperinfection, pharmacologic activation of DAF-12 suppressed autoinfection and markedly reduced lethality. Moreover, when Δ7-DA was administered with ivermectin, the current but limited drug of choice for treating strongyloidiasis, the combinatorial effects of the two drugs resulted in a near cure of the disease.
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http://dx.doi.org/10.7554/eLife.73535 | DOI Listing |
Chembiochem
November 2024
CONICET - Universidad de Buenos Aires, Unidad de Microanálisis y Métodos Físicos en Química Orgánica (UMYMFOR), Ciudad Universitaria, Ciudad Autónoma de Buenos Aires, C1428EGA, Argentina.
Steroid hormones are essential for the biological processes of eukaryotic organisms. The steroid endocrine system of C. elegans, which includes dafachronic acids (DA) and the nuclear receptor ceDAF-12, provides a simple model for exploring the role of steroid hormone signaling pathways in animals.
View Article and Find Full Text PDFElife
December 2021
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States.
A prevalent feature of is a life-long and potentially lethal infection that is due to the nematode parasite's ability to autoinfect and, thereby, self-replicate within its host. Here, we investigated the role of the parasite's nuclear receptor, DAF-12, in governing infection. We identified Δ7-DA as the endogenous DAF-12 ligand and elucidated the hormone's biosynthetic pathway.
View Article and Find Full Text PDFOrg Biomol Chem
June 2021
Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123, Perugia, Italy.
The four cyclopropyl stereoisomers of Δ7-dafachronic acids were prepared from the bile acid hyodeoxycholic acid and employed as chemical tools to exploit the importance of the orientation and spatial disposition of the carboxyl tail and the C25-methyl group for the binding at the DAF-12 receptor. The synthesis route was based on (a) Walden inversion and stereoselective PtO-hydrogenation to convert the L-shaped 5β-cholanoid scaffold into the planar 5α-sterol intermediate; (b) two-carbon homologation of the side chain by Wittig and cyclopropanation reaction; and (c) formation of the 3-keto group and Δ7 double bond. The synthesized isomers were isolated and tested for their activity as DAF-12 ligands by AlphaScreen assays.
View Article and Find Full Text PDFSteroids
November 2019
CONICET-Universidad de Buenos Aires, UMYMFOR, Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Buenos Aires, Argentina. Electronic address:
The DAF-12 receptor is a ligand-activated transcription factor that in its ligand-bound form allows the expression of target genes needed to support the reproductive life cycle of the free-living nematode Caenorhabditis elegans, whereas unbound DAF-12 receptor leads to the developmentally arrested "dauer larvae", specialized for survival and dispersal. The endogenous ligands of the DAF-12 receptor are 3-keto-cholestenoic acids dubbed dafachronic acids. In a previous publication we reported that oxysterols with a shorter side chain (C) modulate the DAF-12 receptor activity either as partial agonists or, in the case of the C alcohol 24-hydroxy-4-cholen-3-one, as an antagonist both in vitro and in vivo.
View Article and Find Full Text PDFFront Genet
July 2019
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States.
DNA transformation of parasitic nematodes enables novel approaches to validating predictions from genomic and transcriptomic studies of these important pathogens. Notably, proof of principle for CRISPR/Cas9 mutagenesis has been achieved in spp., allowing identification of molecules essential to the functions of sensory neurons that mediate behaviors comprising host finding, invasion, and location of predilection sites by parasitic nematodes.
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