scholarly journals Specificity and Complexity of the Caenorhabditis elegans Innate Immune Response

2007 ◽  
Vol 27 (15) ◽  
pp. 5544-5553 ◽  
Author(s):  
Scott Alper ◽  
Sandra J. McBride ◽  
Brad Lackford ◽  
Jonathan H. Freedman ◽  
David A. Schwartz
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Caenorhabditis Elegans ◽  
Signaling Pathways ◽  
Large Set ◽  
Immune Signaling ◽  
C Elegans ◽  
Immunity Genes ◽  
Simple Model System ◽  
Overlapping Sets

ABSTRACT In response to infection, Caenorhabditis elegans produces an array of antimicrobial proteins. To understand the C. elegans immune response, we have investigated the regulation of a large, representative sample of candidate antimicrobial genes. We found that all these putative antimicrobial genes are expressed in tissues exposed to the environment, a position from which they can ward off infection. Using RNA interference to inhibit the function of immune signaling pathways in C. elegans, we found that different immune response pathways regulate expression of distinct but overlapping sets of antimicrobial genes. We also show that different bacterial pathogens regulate distinct but overlapping sets of antimicrobial genes. The patterns of genes induced by pathogens do not coincide with any single immune signaling pathway. Thus, even in this simple model system for innate immunity, striking specificity and complexity exist in the immune response. The unique patterns of antimicrobial gene expression observed when C. elegans is exposed to different pathogens or when different immune signaling pathways are perturbed suggest that a large set of yet to be identified pathogen recognition receptors (PRRs) exist in the nematode. These PRRs must interact in a complicated fashion to induce a unique set of antimicrobial genes. We also propose the existence of an “antimicrobial fingerprint,” which will aid in assigning newly identified C. elegans innate immunity genes to known immune signaling pathways.

Loss of DNase II function in the gonad is associated with a higher expression of antimicrobial genes in Caenorhabditis elegans

2015 ◽  
Vol 470 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Hsiang Yu ◽  
Huey-Jen Lai ◽  
Tai-Wei Lin ◽  
Chang-Shi Chen ◽  
Szecheng J. Lo
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Caenorhabditis Elegans ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Dnase Ii ◽  
C Elegans ◽  
Elevated Expression

This study uncovered NUC-1 and CRN-7 function in germline apoptosis. Mutations of nuc-1 and crn-7 led to elevated expression of five innate-immunity-related genes and demonstrated that DNase II activity is associated with an innate immune response in C. elegans.

scholarly journals Mitochondrial UPR negatively regulates wounding-induced innate immune response in C. elegans epidermis

2021 ◽  
Author(s):  
Jianzhi Zhao ◽  
Hongying Fu ◽  
Hengda Zhou ◽  
Xuecong Ren ◽  
Yuanyuan Wang ◽  
...  
Keyword(s):  
Immune Response ◽  
Signaling Pathways ◽  
Innate Immune Response ◽  
Tissue Damage ◽  
P38 Map Kinase ◽  
Innate Immune ◽  
Loss Of Function ◽  
C Elegans ◽  
Unfolded Protein ◽  
Protein Response

Tissue damage elicits a rapid innate immune response that is essential for efficient wound healing and survival of metazoans. It is well known that p38 MAPK kinase, TGF-β, and hemidesmosome signaling pathways have been involved in wounding-induced innate immunity in C. elegans. Here, we find that loss of function of ATFS-1 increased innate immune response while an elevated level of mitochondrial unfolded protein response (mitoUPR) inhibits the innate immune response upon epidermal wounding. Epidermal wounding triggers the nucleus export of ATFS-1 and inhibits themitoUPR in C. elegans epidermis. Moreover, genetic analysis suggests that ATFS-1 functions upstream of the p38 MAP kinase, TGF-β, and DAF-16 signaling pathways in regulating AMPs induction. Thus, our results suggest that the mitoUPR function as an intracellular signal required to fine-tune innate immune response after tissue damage.

scholarly journals DAF-16 and SMK-1 Contribute to Innate Immunity During Adulthood in Caenorhabditis elegans

2020 ◽  
Vol 10 (5) ◽  
pp. 1521-1539 ◽  
Author(s):  
Daniel R. McHugh ◽  
Elena Koumis ◽  
Paul Jacob ◽  
Jennifer Goldfarb ◽  
Michelle Schlaubitz-Garcia ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune System ◽  
Caenorhabditis Elegans ◽  
Host Defense ◽  
Insulin Signaling ◽  
Bacterial Pathogens ◽  
C Elegans ◽  
Link Type ◽  
Age Dependent ◽  
Over Time

Aging is accompanied by a progressive decline in immune function termed “immunosenescence”. Deficient surveillance coupled with the impaired function of immune cells compromises host defense in older animals. The dynamic activity of regulatory modules that control immunity appears to underlie age-dependent modifications to the immune system. In the roundworm Caenorhabditis elegans levels of PMK-1 p38 MAP kinase diminish over time, reducing the expression of immune effectors that clear bacterial pathogens. Along with the PMK-1 pathway, innate immunity in C. elegans is regulated by the insulin signaling pathway. Here we asked whether DAF-16, a Forkhead box (FOXO) transcription factor whose activity is inhibited by insulin signaling, plays a role in host defense later in life. While in younger C. elegansDAF-16 is inactive unless stimulated by environmental insults, we found that even in the absence of acute stress the transcriptional activity of DAF-16 increases in an age-dependent manner. Beginning in the reproductive phase of adulthood, DAF-16 upregulates a subset of its transcriptional targets, including genes required to kill ingested microbes. Accordingly, DAF-16 has little to no role in larval immunity, but functions specifically during adulthood to confer resistance to bacterial pathogens. We found that DAF-16-mediated immunity in adults requires SMK-1, a regulatory subunit of the PP4 protein phosphatase complex. Our data suggest that as the function of one branch of the innate immune system of C. elegans (PMK-1) declines over time, DAF-16-mediated immunity ramps up to become the predominant means of protecting adults from infection, thus reconfiguring immunity later in life.

scholarly journals FHOD-1 is the only formin in Caenorhabditis elegans that promotes striated muscle growth and Z-line organization in a cell autonomous manner

2020 ◽  
Author(s):  
Sumana Sundaramurthy ◽  
SarahBeth Votra ◽  
Arianna Laszlo ◽  
Tim Davies ◽  
David Pruyne
Keyword(s):  
Caenorhabditis Elegans ◽  
Muscle Cell ◽  
Muscle Development ◽  
Striated Muscle ◽  
Muscle Growth ◽  
Temperature Sensitive ◽  
Direct Role ◽  
C Elegans ◽  
Simple Model System ◽  
Body Wall Muscles

AbstractThe striated body wall muscles of Caenorhabditis elegans are a simple model system with well-characterized sarcomeres that have many vertebrate protein homologs. Previously, we observed deletion mutants for two formin genes, fhod-1 and cyk-1, developed thin muscles with abnormal dense bodies/sarcomere Z-lines. However, the nature of the cyk-1 mutation necessitated maternal CYK-1 expression for viability of the examined animals. Here, we tested the effects of complete loss of CYK-1 using a fast acting temperature-sensitive cyk-1(ts) mutant. Surprisingly, neither post-embryonic loss of CYK-1 nor acute loss of CYK-1 during embryonic sarcomerogenesis caused muscle defects, suggesting CYK-1 might not play a direct role in muscle development. Consistent with this, examination of cyk-1(Δ) mutants re-expressing CYK-1 in a mosaic pattern showed CYK-1 cannot rescue muscle defects in a muscle cell autonomous manner, suggesting muscle phenotypes caused by cyk-1 deletion are likely indirect. Conversely, mosaic re-expression of FHOD-1 in fhod-1(Δ) mutants promoted muscle cell growth, as well as proper Z-line organization, in a muscle cell autonomous manner. As we can observe no effect of loss of any other worm formin on muscle development, we conclude that FHOD-1 is the only formin that directly promotes striated muscle development in C. elegans.

scholarly journals Mitochondrial DNA: A Key Regulator of Anti-Microbial Innate Immunity

Genes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 86 ◽  
Author(s):  
Saima Kausar ◽  
Liqun Yang ◽  
Muhammad Nadeem Abbas ◽  
Xin Hu ◽  
Yongju Zhao ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Mitochondrial Dna ◽  
Signaling Pathways ◽  
Inflammatory Diseases ◽  
Cpg Islands ◽  
Innate Immune ◽  
Cellular Damage ◽  
Immune Signaling ◽  
Molecular Pattern ◽  
Characteristic Features

During the last few years, mitochondrial DNA has attained much attention as a modulator of immune responses. Due to common evolutionary origin, mitochondrial DNA shares various characteristic features with DNA of bacteria, as it consists of a remarkable number of unmethylated DNA as 2′-deoxyribose cytidine-phosphate-guanosine (CpG) islands. Due to this particular feature, mitochondrial DNA seems to be recognized as a pathogen-associated molecular pattern by the innate immune system. Under the normal physiological situation, mitochondrial DNA is enclosed in the double membrane structure of mitochondria. However, upon pathological conditions, it is usually released into the cytoplasm. Growing evidence suggests that this cytosolic mitochondrial DNA induces various innate immune signaling pathways involving NLRP3, toll-like receptor 9, and stimulator of interferon genes (STING) signaling, which participate in triggering downstream cascade and stimulating to produce effector molecules. Mitochondrial DNA is responsible for inflammatory diseases after stress and cellular damage. In addition, it is also involved in the anti-viral and anti-bacterial innate immunity. Thus, instead of entire mitochondrial importance in cellular metabolism and energy production, mitochondrial DNA seems to be essential in triggering innate anti-microbial immunity. Here, we describe existing knowledge on the involvement of mitochondrial DNA in the anti-microbial immunity by modulating the various immune signaling pathways.

Take a Walk to the Wild Side of Caenorhabditis elegans-Pathogen Interactions

2021 ◽  
Vol 85 (2) ◽  
Author(s):  
Leah J. Radeke ◽  
Michael A. Herman
Keyword(s):  
Innate Immunity ◽  
Caenorhabditis Elegans ◽  
Recent Work ◽  
Genetic Model ◽  
Model Organism ◽  
Bacterial Pathogen ◽  
Content Type ◽  
Microbiome Composition ◽  
C Elegans ◽  
Functional Studies

SUMMARY Microbiomes form intimate functional associations with their hosts. Much has been learned from correlating changes in microbiome composition to host organismal functions. However, in-depth functional studies require the manipulation of microbiome composition coupled with the precise interrogation of organismal physiology—features available in few host study systems. Caenorhabditis elegans has proven to be an excellent genetic model organism to study innate immunity and, more recently, microbiome interactions. The study of C. elegans-pathogen interactions has provided in depth understanding of innate immune pathways, many of which are conserved in other animals. However, many bacteria were chosen for these studies because of their convenience in the lab setting or their implication in human health rather than their native interactions with C. elegans. In their natural environment, C. elegans feed on a variety of bacteria found in rotting organic matter, such as rotting fruits, flowers, and stems. Recent work has begun to characterize the native microbiome and has identified a common set of bacteria found in the microbiome of C. elegans. While some of these bacteria are beneficial to C. elegans health, others are detrimental, leading to a complex, multifaceted understanding of bacterium-nematode interactions. Current research on nematode-bacterium interactions is focused on these native microbiome components, both their interactions with each other and with C. elegans. We will summarize our knowledge of bacterial pathogen-host interactions in C. elegans, as well as recent work on the native microbiome, and explore the incorporation of these bacterium-nematode interactions into studies of innate immunity and pathogenesis.

scholarly journals Virulence of Leucobacter chromiireducens subsp. solipictus to Caenorhabditis elegans: Characterization of a Novel Host-Pathogen Interaction

2008 ◽  
Vol 74 (13) ◽  
pp. 4185-4198 ◽  
Author(s):  
Rachel E. Muir ◽  
Man-Wah Tan
Keyword(s):  
Innate Immunity ◽  
Caenorhabditis Elegans ◽  
Food Source ◽  
Strongly Correlated ◽  
C Elegans ◽  
Novel Host ◽  
Fat Stores ◽  
Pathogenic Interaction ◽  
Host Life

ABSTRACT We describe the pathogenic interaction between a newly described gram-positive bacterium, Leucobacter chromiireducens subsp. solipictus strain TAN 31504, and the nematode Caenorhabditis elegans. TAN 31504 pathogenesis on C. elegans is exerted primarily through infection of the adult nematode uterus. TAN 31504 enters the uterus through the external vulval opening, and the ensuing uterine infection is strongly correlated with a significant reduction in host life span. Young worms can feed and develop on TAN 31504, but not preferably over the standard food source. C. elegans worms reared on TAN 31504 as the sole food source develop into thin adults with little intestinal fat stores, produce few progeny, and subsequently cannot persist on the pathogenic food source. Within 12 h of exposure, adult worms challenged with TAN 31504 alter the expression of a number of C. elegans innate immunity-related genes, including nlp-29, which encodes a neuropeptide-like protein. C. elegans worms exposed briefly to TAN 31504 develop lethal uterine infections analogous to worms exposed continuously to pathogen, suggesting that mere contact with the pathogen is sufficient for the host to become infected. TAN 31504 produces a robust biofilm, and this behavior is speculated to play a role in the virulence exerted on the nematode host. The interaction between TAN 31504 and C. elegans provides a convenient opportunity to study bacterial virulence on nematode tissues other than the intestine and may allow for the discovery of host innate immunity elicited specifically in response to vulva-uterus infection.

scholarly journals Analysis of the Caenorhabditis elegans innate immune response to Coxiella burnetii

2016 ◽  
Vol 23 (2) ◽  
pp. 111-127 ◽  
Author(s):  
James M Battisti ◽  
Lance A Watson ◽  
Myo T Naung ◽  
Adam M Drobish ◽  
Ekaterina Voronina ◽  
...  
Keyword(s):  
Immune Response ◽  
Caenorhabditis Elegans ◽  
Innate Immune Response ◽  
Coxiella Burnetii ◽  
Molecular Mechanisms ◽  
Q Fever ◽  
Innate Immune ◽  
Human Pathogens ◽  
C Elegans ◽  
Intestinal Distension

The nematode Caenorhabditis elegans is well established as a system for characterization and discovery of molecular mechanisms mediating microbe-specific inducible innate immune responses to human pathogens. Coxiella burnetii is an obligate intracellular bacterium that causes a flu-like syndrome in humans (Q fever), as well as abortions in domesticated livestock, worldwide. Initially, when wild type C. elegans (N2 strain) was exposed to mCherry-expressing C. burnetii (CCB) a number of overt pathological manifestations resulted, including intestinal distension, deformed anal region and a decreased lifespan. However, nematodes fed autoclave-killed CCB did not exhibit these symptoms. Although vertebrates detect C. burnetii via TLRs, pathologies in tol-1(–) mutant nematodes were indistinguishable from N2, and indicate nematodes do not employ this orthologue for detection of C. burnetii. sek-1(–) MAP kinase mutant nematodes succumbed to infection faster, suggesting that this signaling pathway plays a role in immune activation, as previously shown for orthologues in vertebrates during a C. burnetii infection. C. elegans daf-2(–) mutants are hyper-immune and exhibited significantly reduced pathological consequences during challenge. Collectively, these results demonstrate the utility of C. elegans for studying the innate immune response against C. burnetii and could lead to discovery of novel methods for prevention and treatment of disease in humans and livestock.

scholarly journals PKA/KIN-1 mediates innate immune responses to bacterial pathogens in Caenorhabditis elegans

2017 ◽  
Vol 23 (8) ◽  
pp. 656-666 ◽  
Author(s):  
Yi Xiao ◽  
Fang Liu ◽  
Pei-ji Zhao ◽  
Cheng-Gang Zou ◽  
Ke-Qin Zhang
Keyword(s):  
Innate Immunity ◽  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Immune Responses ◽  
Innate Immune ◽  
Autophagic Flux ◽  
Innate Immune Responses ◽  
C Elegans ◽  
Downstream Effector ◽  
Model Animal

The genetically tractable organism Caenorhabditis elegans is a powerful model animal for the study of host innate immunity. Although the intestine and the epidermis of C. elegans that is in contact with pathogens are likely to function as sites for the immune function, recent studies indicate that the nervous system could control innate immunity in C. elegans. In this report, we demonstrated that protein kinase A (PKA)/KIN-1 in the neurons contributes to resistance against Salmonella enterica infection in C. elegans. Microarray analysis revealed that PKA/KIN-1 regulates the expression of a set of antimicrobial effectors in the non-neuron tissues, which are required for innate immune responses to S. enterica. Furthermore, PKA/KIN-1 regulated the expression of lysosomal genes during S. enterica infection. Our results suggest that the lysosomal signaling molecules are involved in autophagy by controlling autophagic flux, rather than formation of autophagosomes. As autophagy is crucial for host defense against S. enterica infection in a metazoan, the lysosomal pathway also acts as a downstream effector of the PKA/KIN-1 signaling for innate immunity. Our data indicate that the PKA pathway contributes to innate immunity in C. elegans by signaling from the nervous system to periphery tissues to protect the host against pathogens.

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