Search

Alzheimer's, Parkinson's and Huntington's diseases can be caused by mutations that enhance protein aggregation, but we still do not know enough about the molecular players of these pathways to develop treatments for these devastating diseases. Here, we screen for mutations that might enhance aggregation in Caenorhabditis elegans, to investigate the mechanisms that protect against dysregulated homeostasis. We report that the stomatin homologue UNC-1 activates neurohormonal signalling from the sulfotransferase SSU-1 in ASJ sensory/endocrine neurons. A putative hormone, produced in ASJ, targets the nuclear receptor NHR-1, which acts cell autonomously in the muscles to modulate polyglutamine repeat (polyQ) aggregation. A second nuclear receptor, DAF-12, functions oppositely to NHR-1 to maintain protein homeostasis. Transcriptomics analyses of unc-1 mutants revealed changes in the expression of genes involved in fat metabolism, suggesting that fat metabolism changes, controlled by neurohormonal signalling, contribute to protein homeostasis. Furthermore, the enzymes involved in the identified signalling pathway are potential targets for treating neurodegenerative diseases caused by disrupted protein homeostasis., (© 2023 The Authors. Published under the terms of the CC BY 4.0 license.)

SWItch/sucrose non-fermenting (SWI/SNF) complexes are a family of chromatin remodelers that are conserved across eukaryotes. Mutations in subunits of SWI/SNF cause a multitude of different developmental disorders in humans, most of which have no current treatment options. Here, we identify an alanine-to-valine-causing mutation in the SWI/SNF subunit snfc-5 ( SMARCB1 in humans) that prevents embryonic lethality in Caenorhabditis elegans nematodes harboring a loss-of-function mutation in the SWI/SNF subunit swsn-1 ( SMARCC1/2 in humans). Furthermore, we found that the combination of this specific mutation in snfc-5 and a loss-of-function mutation in either of the E3 ubiquitin ligases ubr-5 ( UBR5 in humans) or hecd-1 ( HECTD1 in humans) can restore development to adulthood in swsn-1 loss-of-function mutants that otherwise die as embryos. Using these mutant models, we established a set of 335 genes that are dysregulated in SWI/SNF mutants that arrest their development embryonically but exhibit near wild-type levels of expression in the presence of suppressor mutations that prevent embryonic lethality, suggesting that SWI/SNF promotes development by regulating some subset of these 335 genes. In addition, we show that SWI/SNF protein levels are reduced in swsn-1; snfc-5 double mutants and partly restored to wild-type levels in swsn-1; snfc-5; ubr-5 triple mutants, consistent with a model in which UBR-5 regulates SWI/SNF levels by tagging the complex for proteasomal degradation. Our findings establish a link between two E3 ubiquitin ligases and SWI/SNF function and suggest that UBR5 and HECTD1 could be potential therapeutic targets for the many developmental disorders caused by missense mutations in SWI/SNF subunits.

In the fight to resist environmental toxins, Caenorhabditis elegans might have co-opted cysteine-synthase-related enzymes that were likely acquired from algae and then integrated them into a hypoxia-signaling pathway to adapt to cyanide., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Parental exposure to pathogens can prime offspring immunity in diverse organisms. The mechanisms by which this heritable priming occurs are largely unknown. Here we report that the soil bacteria Pseudomonas vranovensis is a natural pathogen of the nematode Caenorhabditis elegans and that parental exposure of animals to P. vranovensis promotes offspring resistance to infection. Furthermore, we demonstrate a multigenerational enhancement of progeny survival when three consecutive generations of animals are exposed to P. vranovensis. By investigating the mechanisms by which animals heritably adapt to P. vranovensis infection, we found that parental infection by P. vranovensis results in increased expression of the cysteine synthases cysl-1 and cysl-2 and the regulator of hypoxia inducible factor rhy-1 in progeny, and that these three genes are required for adaptation to P. vranovensis. These observations establish a CYSL-1, CYSL-2, and RHY-1 dependent mechanism by which animals heritably adapt to infection.