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Aberrant Activation of p38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis elegans.
G3 (Bethesda). 2016 Jan 27; 6(3):541-9.G

Abstract

Inappropriate activation of innate immune responses in intestinal epithelial cells underlies the pathophysiology of inflammatory disorders of the intestine. Here we examine the physiological effects of immune hyperactivation in the intestine of the nematode Caenorhabditis elegans. We previously identified an immunostimulatory xenobiotic that protects C. elegans from bacterial infection by inducing immune effector expression via the conserved p38 MAP kinase pathway, but was toxic to nematodes developing in the absence of pathogen. To investigate a possible connection between the toxicity and immunostimulatory properties of this xenobiotic, we conducted a forward genetic screen for C. elegans mutants that are resistant to the deleterious effects of the compound, and identified five toxicity suppressors. These strains contained hypomorphic mutations in each of the known components of the p38 MAP kinase cassette (tir-1, nsy-1, sek-1, and pmk-1), demonstrating that hyperstimulation of the p38 MAPK pathway is toxic to animals. To explore mechanisms of immune pathway regulation in C. elegans, we conducted another genetic screen for dominant activators of the p38 MAPK pathway, and identified a single allele that had a gain-of-function (gf) mutation in nsy-1, the MAP kinase kinase kinase that acts upstream of p38 MAPK pmk-1. The nsy-1(gf) allele caused hyperinduction of p38 MAPK PMK-1-dependent immune effectors, had greater levels of phosphorylated p38 MAPK, and was more resistant to killing by the bacterial pathogen Pseudomonas aeruginosa compared to wild-type controls. In addition, the nsy-1(gf) mutation was toxic to developing animals. Together, these data suggest that the activity of the MAPKKK NSY-1 is tightly regulated as part of a physiological mechanism to control p38 MAPK-mediated innate immune hyperactivation, and ensure cellular homeostasis in C. elegans.

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Authors+Show Affiliations

Cheesman HK
Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
Feinbaum RL
Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114.
Thekkiniath J
Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
Dowen RH
Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114.
Conery AL
Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114.
Pukkila-Worley R
Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605 Pukkila-Worley@umassmed.edu.

MeSH

AllelesAnimalsCaenorhabditis elegansCaenorhabditis elegans ProteinsDisease ResistanceEnzyme ActivationGene ExpressionGenetic VariationImmunity, InnateMAP Kinase Signaling SystemMutationPhenotypeProtein Serine-Threonine KinasesRNA Interferencep38 Mitogen-Activated Protein Kinases

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

26818074

Citation

Cheesman, Hilary K., et al. "Aberrant Activation of P38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis Elegans." G3 (Bethesda, Md.), vol. 6, no. 3, 2016, pp. 541-9.
Cheesman HK, Feinbaum RL, Thekkiniath J, et al. Aberrant Activation of p38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis elegans. G3 (Bethesda). 2016;6(3):541-9.
Cheesman, H. K., Feinbaum, R. L., Thekkiniath, J., Dowen, R. H., Conery, A. L., & Pukkila-Worley, R. (2016). Aberrant Activation of p38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis elegans. G3 (Bethesda, Md.), 6(3), 541-9. https://doi.org/10.1534/g3.115.025650
Cheesman HK, et al. Aberrant Activation of P38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis Elegans. G3 (Bethesda). 2016 Jan 27;6(3):541-9. PubMed PMID: 26818074.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Aberrant Activation of p38 MAP Kinase-Dependent Innate Immune Responses Is Toxic to Caenorhabditis elegans. AU - Cheesman,Hilary K, AU - Feinbaum,Rhonda L, AU - Thekkiniath,Jose, AU - Dowen,Robert H, AU - Conery,Annie L, AU - Pukkila-Worley,Read, Y1 - 2016/01/27/ PY - 2016/1/29/entrez PY - 2016/1/29/pubmed PY - 2016/12/15/medline KW - C. elegans genetics KW - genetics of immunity KW - host-pathogen interactions KW - immune regulation KW - innate immunity SP - 541 EP - 9 JF - G3 (Bethesda, Md.) JO - G3 (Bethesda) VL - 6 IS - 3 N2 - Inappropriate activation of innate immune responses in intestinal epithelial cells underlies the pathophysiology of inflammatory disorders of the intestine. Here we examine the physiological effects of immune hyperactivation in the intestine of the nematode Caenorhabditis elegans. We previously identified an immunostimulatory xenobiotic that protects C. elegans from bacterial infection by inducing immune effector expression via the conserved p38 MAP kinase pathway, but was toxic to nematodes developing in the absence of pathogen. To investigate a possible connection between the toxicity and immunostimulatory properties of this xenobiotic, we conducted a forward genetic screen for C. elegans mutants that are resistant to the deleterious effects of the compound, and identified five toxicity suppressors. These strains contained hypomorphic mutations in each of the known components of the p38 MAP kinase cassette (tir-1, nsy-1, sek-1, and pmk-1), demonstrating that hyperstimulation of the p38 MAPK pathway is toxic to animals. To explore mechanisms of immune pathway regulation in C. elegans, we conducted another genetic screen for dominant activators of the p38 MAPK pathway, and identified a single allele that had a gain-of-function (gf) mutation in nsy-1, the MAP kinase kinase kinase that acts upstream of p38 MAPK pmk-1. The nsy-1(gf) allele caused hyperinduction of p38 MAPK PMK-1-dependent immune effectors, had greater levels of phosphorylated p38 MAPK, and was more resistant to killing by the bacterial pathogen Pseudomonas aeruginosa compared to wild-type controls. In addition, the nsy-1(gf) mutation was toxic to developing animals. Together, these data suggest that the activity of the MAPKKK NSY-1 is tightly regulated as part of a physiological mechanism to control p38 MAPK-mediated innate immune hyperactivation, and ensure cellular homeostasis in C. elegans. SN - 2160-1836 UR - https://www.unboundmedicine.com/medline/citation/26818074/Aberrant_Activation_of_p38_MAP_Kinase_Dependent_Innate_Immune_Responses_Is_Toxic_to_Caenorhabditis_elegans_ DB - PRIME DP - Unbound Medicine ER -