HIF-1 and SKN-1 Coordinate the Transcriptional Response to Hydrogen Sulfide in Caenorhabditis elegans

Knowledge of how anthelmintics are metabolized and excreted in nematodes is an integral part of understanding the factors that determine their potency, spectrum of activity and for investigating mechanisms of resistance. Although there is remarkably little information on these processes in nematodes, it is often suggested that they are of minimal importance for the major anthelmintic drugs. Consequently, we have investigated how the model nematode Caenorhabditis elegans responds to and metabolizes albendazole, one of the most important anthelmintic drugs for human and animal use. Using a mutant strain lacking the β-tubulin drug target to minimize generalized stress responses, we show that the transcriptional response is dominated by genes encoding XMEs (xenobiotic-metabolizing enzymes), particularly cytochrome P450s and UGTs (UDP-glucuronosyl transferases). The most highly induced genes are predominantly expressed in the worm intestine, supporting their role in drug metabolism. HPLC-MS/MS revealed the production of two novel glucoside metabolites in C. elegans identifying a major difference in the biotransformation of this drug between nematodes and mammals. This is the first demonstration of metabolism of a therapeutic anthelmintic in C. elegans and provides a framework for its use to functionally investigate nematode anthelmintic metabolism.

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Remodeling of the Caenorhabditis elegans non-coding RNA transcriptome by heat shock

Nucleic Acids Research ◽

10.1093/nar/gkz693 ◽

2019 ◽

Vol 47 (18) ◽

pp. 9829-9841 ◽

Cited By ~ 6

Author(s):

William P Schreiner ◽

Delaney C Pagliuso ◽

Jacob M Garrigues ◽

Jerry S Chen ◽

Antti P Aalto ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Heat Shock ◽

Elevated Temperatures ◽

Transcriptional Response ◽

Heat Shock Factor 1 ◽

Protein Coding ◽

Repeat Elements ◽

Cellular Survival ◽

Non Coding Rna ◽

Shock Proteins

Abstract Elevated temperatures activate a heat shock response (HSR) to protect cells from the pathological effects of protein mis-folding, cellular mis-organization, organelle dysfunction and altered membrane fluidity. This response includes activation of the conserved transcription factor heat shock factor 1 (HSF-1), which binds heat shock elements (HSEs) in the promoters of genes induced by heat shock (HS). The upregulation of protein-coding genes (PCGs), such as heat shock proteins and cytoskeletal regulators, is critical for cellular survival during elevated temperatures. While the transcriptional response of PCGs to HS has been comprehensively analyzed in a variety of organisms, the effect of this stress on the expression of non-coding RNAs (ncRNAs) has not been systematically examined. Here we show that in Caenorhabditis elegans HS induces up- and downregulation of specific ncRNAs from multiple classes, including miRNA, piRNA, lincRNA, pseudogene and repeat elements. Moreover, some ncRNA genes appear to be direct targets of the HSR, as they contain HSF-1 bound HSEs in their promoters and their expression is regulated by this factor during HS. These results demonstrate that multiple ncRNA genes respond to HS, some as direct HSF-1 targets, providing new candidates that may contribute to organismal survival during this stress.

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Identification of a novel hydrogen sulfide-generating Caenorhabditis elegans protein, SEMO-1, that is orthologous to human selenium-binding protein 1 and modulates lifespan

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2021.08.066 ◽

2021 ◽

Vol 177 ◽

pp. S68

Author(s):

Thilo Philipp ◽

Karl Köhnlein ◽

Andreas Johannes Will ◽

Holger Steinbrenner ◽

Lars-Oliver Klotz

Keyword(s):

Hydrogen Sulfide ◽

Caenorhabditis Elegans ◽

Binding Protein

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C. elegans RHY-1 and CYSL-1 act independently of HIF-1 to promote survival in hydrogen sulfide

10.1101/628784 ◽

2019 ◽

Author(s):

Joseph W. Horsman ◽

Frazer I. Heinis ◽

Dana L. Miller

Keyword(s):

Hydrogen Sulfide ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Single Gene ◽

Hypoxia Inducible Factor ◽

Transcriptional Response ◽

C Elegans ◽

Suppressor Mutations ◽

Low Concentrations ◽

Transcription Factor Activation

AbstractHydrogen sulfide (H2S) is an endogenously produced signaling molecule that can be cytoprotective, especially in conditions of ischemia/reperfusion injury. However, exposure to exogenous H2S can be toxic, perhaps due to unregulated activation of endogenous H2S signaling pathways. We use the nematode C. elegans to define mechanisms that mediate the physiological effects of H2S in animals. We have previously shown that in C. elegans the hypoxia inducible factor (hif-1) coordinates the initial transcriptional response to H2S and is essential to survive exposure to low concentrations of H2S. In this study, we performed a forward genetic screen to identify mutations that suppress the lethality of hif-1 mutant animals in H2S. The mutations we recovered do not suppress embryonic lethality or reproductive arrest of hif-1 mutant animals in hypoxia, nor can they improve viability of hif-1 mutant animals exposed to hydrogen cyanide, indicating that these are specific for H2S. We found that the hif-1 suppressor mutations activate the skn-1/Nrf2 transcription factor. Activation of SKN-1 by hif-1 suppressor mutations increased the expression of a subset of H2S-responsive genes, consistent with our previous finding that skn-1 plays a role in the transcriptional response to H2S. Using transgenic rescue, we show a single gene, rhy-1, alone is sufficient to protect hif-1 mutant animals in H2S. Our data indicate that RHY-1 acts in concert with CYSL-1, an orthologue of human cystathionine β-synthase, to promote survival in H2S. The rhy-1 gene encodes a predicated O-acyltransferase enzyme that has previously been shown to negatively regulate HIF-1 activity. Our studies reveal a novel function of RHY-1, which is independent of hif-1, that protects against toxic effects of H2S.

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Caenorhabditis elegans AF4/FMR2 Family Homolog affl-2 Regulates Heat-Shock-Induced Gene Expression

Genetics ◽

10.1534/genetics.120.302923 ◽

2020 ◽

Vol 215 (4) ◽

pp. 1039-1054

Author(s):

Sophie J. Walton ◽

Han Wang ◽

Porfirio Quintero-Cadena ◽

Alex Bateman ◽

Paul W. Sternberg

Keyword(s):

Gene Expression ◽

Heat Stress ◽

Caenorhabditis Elegans ◽

Heat Shock ◽

Heat Shock Response ◽

Genetic Locus ◽

Transcriptional Response ◽

Transcriptional Elongation ◽

Link Type ◽

Shock Response

To mitigate the deleterious effects of temperature increases on cellular organization and proteotoxicity, organisms have developed mechanisms to respond to heat stress. In eukaryotes, HSF1 is the master regulator of the heat shock transcriptional response, but the heat shock response pathway is not yet fully understood. From a forward genetic screen for suppressors of heat-shock-induced gene expression in Caenorhabditis elegans, we found a new allele of hsf-1 that alters its DNA-binding domain, and we found three additional alleles of sup-45, a previously molecularly uncharacterized genetic locus. We identified sup-45 as one of the two hitherto unknown C. elegans orthologs of the human AF4/FMR2 family proteins, which are involved in regulation of transcriptional elongation rate. We thus renamed sup-45 as affl-2 (AF4/FMR2-Like). Through RNA-seq, we demonstrated that affl-2 mutants are deficient in heat-shock-induced transcription. Additionally, affl-2 mutants have herniated intestines, while worms lacking its sole paralog (affl-1) appear wild type. AFFL-2 is a broadly expressed nuclear protein, and nuclear localization of AFFL-2 is necessary for its role in heat shock response. affl-2 and its paralog are not essential for proper HSF-1 expression and localization after heat shock, which suggests that affl-2 may function downstream of, or parallel to, hsf-1. Our characterization of affl-2 provides insights into the regulation of heat-shock-induced gene expression to protect against heat stress.

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Transcriptional response of Caenorhabditis elegans when exposed to Shigella flexneri

Genomics ◽

10.1016/j.ygeno.2019.05.016 ◽

2020 ◽

Vol 112 (1) ◽

pp. 774-781 ◽

Cited By ~ 2

Author(s):

Pamodha Somasiri ◽

Carolyn A. Behm ◽

Marcin Adamski ◽

Jiayu Wen ◽

Naresh K. Verma

Keyword(s):

Caenorhabditis Elegans ◽

Shigella Flexneri ◽

Transcriptional Response

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Novel structural arrangement of nematode cystathionine β-synthases: characterization of Caenorhabditis elegans CBS-1

Biochemical Journal ◽

10.1042/bj20111478 ◽

2012 ◽

Vol 443 (2) ◽

pp. 535-547 ◽

Cited By ~ 23

Author(s):

Roman Vozdek ◽

Aleš Hnízda ◽

Jakub Krijt ◽

Marta Kostrouchová ◽

Viktor Kožich

Keyword(s):

Hydrogen Sulfide ◽

Caenorhabditis Elegans ◽

Mutant Proteins ◽

Structural Arrangement ◽

C Elegans ◽

Single Polypeptide Chain ◽

Evolutionarily Conserved ◽

Catalytically Active ◽

Single Polypeptide ◽

Truncated Variants

CBSs (cystathionine β-synthases) are eukaryotic PLP (pyridoxal 5 *-phosphate)-dependent proteins that maintain cellular homocysteine homoeostasis and produce cystathionine and hydrogen sulfide. In the present study, we describe a novel structural arrangement of the CBS enzyme encoded by the cbs-1 gene of the nematode Caenorhabditis elegans. The CBS-1 protein contains a unique tandem repeat of two evolutionarily conserved catalytic regions in a single polypeptide chain. These repeats include a catalytically active C-terminal module containing a PLP-binding site and a less conserved N-terminal module that is unable to bind the PLP cofactor and cannot catalyse CBS reactions, as demonstrated by analysis of truncated variants and active-site mutant proteins. In contrast with other metazoan enzymes, CBS-1 lacks the haem and regulatory Bateman domain essential for activation by AdoMet (S-adenosylmethionine) and only forms monomers. We determined the tissue and subcellular distribution of CBS-1 and showed that cbs-1 knockdown by RNA interference leads to delayed development and to an approximately 10-fold elevation of homocysteine concentrations in nematode extracts. The present study provides the first insight into the metabolism of sulfur amino acids and hydrogen sulfide in C. elegans and shows that nematode CBSs possess a structural feature that is unique among CBS proteins.

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