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

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.

2016 ◽  
Vol 23 (2) ◽  
pp. 111-127 ◽  
Author(s):  
James M Battisti ◽  
Lance A Watson ◽  
Myo T Naung ◽  
Adam M Drobish ◽  
Ekaterina Voronina ◽  
...  

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.


2015 ◽  
Vol 112 (18) ◽  
pp. E2366-E2375 ◽  
Author(s):  
Zhiji Ren ◽  
Victor R. Ambros

Animals maintain their developmental robustness against natural stresses through numerous regulatory mechanisms, including the posttranscriptional regulation of gene expression by microRNAs (miRNAs). Caenorhabditis elegans miRNAs of the let-7 family (let-7-Fam) function semiredundantly to confer robust stage specificity of cell fates in the hypodermal seam cell lineages. Here, we show reciprocal regulatory interactions between let-7-Fam miRNAs and the innate immune response pathway in C. elegans. Upon infection of C. elegans larvae with the opportunistic human pathogen Pseudomonas aeruginosa, the developmental timing defects of certain let-7-Fam miRNA mutants are enhanced. This enhancement is mediated by the p38 MAPK innate immune pathway acting in opposition to let-7-Fam miRNA activity, possibly via the downstream Activating Transcription Factor-7 (ATF-7). Furthermore, let-7-Fam miRNAs appear to exert negative regulation on the worm’s resistance to P. aeruginosa infection. Our results show that the inhibition of pathogen resistance by let-7 involves downstream heterochronic genes and the p38 MAPK pathway. These findings suggest that let-7-Fam miRNAs are integrated into innate immunity gene regulatory networks, such that this family of miRNAs modulates immune responses while also ensuring robust timing of developmental events under pathogen stress.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ruben Prado ◽  
Gai-Linn Bessing ◽  
Nathaniel Snyder ◽  
Gurpalik Singh ◽  
Frank Yang ◽  
...  

Background and Hypothesis: Lyme disease is caused by the spirochaete bacteria from the Borrelia species. Recent studies suggest that Lyme disease may be associated with dementia, brain atrophy, and protein aggregates that may be associated with the development of neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimers disease (AD). The molecular basis of the Borrelia-associated innate immune response and associated neuropathology is poorly defined.  A significant hindrance in dissecting these molecular components is the lack of facile in vivo genetic models to explore the mechanisms involved in the neuropathology. Here we hypothesize that the nematode C. elegans will be a useful model for Borrelia-associated innate immunity and neuropathology.  Project Methods: We utilized transcriptional reporters, transgenic animals, neuronal morphology analysis, RNAi, host defense pathways, AD- and PD-associated pathologies, and behavior assays to determine the effect that Borrelia has on C. elegans viability.  Results: C. elegans can be infected and survive using Borrelia as a food source, and the bacteria can induce highly conserved innate immune response pathways, and exacerbate PD-associated dopamine neuronal death in human A53T -synuclein-expressing animals. C. elegans models expressing AD-associated human A 1-42 also show significant movement defects and increased protein aggregates when exposed to Borrelia.  Conclusions and Potential Impact: This study further characterizes a novel genetic model for Borrelia-associated innate immunity and neuropathology. Incorporating C. elegans genetic screens, this model should allow us to identify mediators of the Borrelia-associated pathologies that should facilitate the identification of molecular pathways and potential therapeutic targets.


2018 ◽  
Author(s):  
Marissa Fletcher ◽  
Erik J. Tillman ◽  
Vincent L. Butty ◽  
Stuart S. Levine ◽  
Dennis H. Kim

AbstractThe nematode Caenorhabditis elegans has emerged as a genetically tractable animal host in which to study evolutionarily conserved mechanisms of innate immune signaling. We previously showed that the PMK-1 p38 mitogen-activated protein kinase (MAPK) pathway regulates innate immunity of C. elegans through phosphorylation of the CREB/ATF bZIP transcription factor, ATF-7. Here, we have undertaken a genomic analysis of the transcriptional response of C. elegans to infection by Pseudomonas aeruginosa, combining genome-wide expression analysis by RNA-seq with ATF-7 chromatin immunoprecipitation followed by sequencing (ChIP-Seq). We observe that PMK-1-ATF-7 activity regulates a majority of all genes induced by pathogen infection, and observe ATF-7 occupancy in regulatory regions of pathogen-induced genes in a PMK-1-dependent manner. Moreover, functional analysis of a subset of these ATF-7-regulated pathogen-induced target genes supports a direct role for this transcriptional response in host defense. The genome-wide regulation through PMK-1– ATF-7 signaling reveals global control over the innate immune response to infection through a single transcriptional regulator in a simple animal host.Author SummaryInnate immunity is the first line of defense against invading microbes across metazoans. Caenorhabditis elegans lacks adaptive immunity and is therefore particularly dependent on mounting an innate immune response against pathogens. A major component of this response is the conserved PMK-1/p38 MAPK signaling cascade, the activation of which results in phosphorylation of the bZIP transcription factor ATF-7. Signaling via PMK-1 and ATF-7 causes broad transcriptional changes including the induction of many genes that are predicted to have antimicrobial activity including C-type lectins and lysozymes. In this study, we show that ATF-7 directly regulates the majority of innate immune response genes upon pathogen infection of C. elegans, and demonstrate that many ATF-7 targets function to promote pathogen resistance.


2021 ◽  
Author(s):  
Jianzhi Zhao ◽  
Hongying Fu ◽  
Hengda Zhou ◽  
Xuecong Ren ◽  
Yuanyuan Wang ◽  
...  

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.


Author(s):  
Dalia Cicily Kattiparambil Dixon ◽  
Chameli Ratan ◽  
Bhagyalakshmi Nair ◽  
Sabitha Mangalath ◽  
Rachy Abraham ◽  
...  

: Innate immunity is the first line of defence elicited by the host immune system to fight against invading pathogens such as viruses and bacteria. From this elementary immune response, the more complex antigen-specific adaptive responses are recruited to provide a long-lasting memory against the pathogens. Innate immunity gets activated when the host cell utilizes a diverse set of receptors known as pattern recognition receptors (PRR) to recognize the viruses that have penetrated the host and respond with cellular processes like complement system, phagocytosis, cytokine release and inflammation and destruction of NK cells. Viral RNA or DNA or viral intermediate products are recognized by receptors like toll-like receptors(TLRs), nucleotide oligomerization domain(NOD)-like receptors (NLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) thereby, inducing type I interferon response (IFN) and other proinflammatory cytokines in infected cells or other immune cells. But certain viruses can evade the host innate immune response to replicate efficiently, triggering the spread of the viral infection. The present review describes the similarity in the mechanism chosen by viruses from different families -HIV, SARS-CoV2 and Nipah viruses to evade the innate immune response and how efficiently they establish the infection in the host. The review also addresses the stages of developments of various vaccines against these viral diseases and the challenges encountered by the researchers during vaccine development.


2019 ◽  
Vol 49 (1) ◽  
pp. 100-117.e6 ◽  
Author(s):  
Sandeep Kumar ◽  
Brian M. Egan ◽  
Zuzana Kocsisova ◽  
Daniel L. Schneider ◽  
John T. Murphy ◽  
...  

2019 ◽  
Vol 20 (13) ◽  
pp. 3357
Author(s):  
Yang Xu ◽  
Huan Zhao ◽  
Yang Tian ◽  
Kaixia Ren ◽  
Nan Zheng ◽  
...  

Protein kinase C-δ (PKC-δ) is an important protein in the immune system of higher vertebrates. Lampreys, as the most primitive vertebrates, have a uniquevariable lymphocyte receptor (VLR) immune system. PKC-δ-like is a crucial functional gene in lampreys and is highly expressed in their immune organs. In this study, lampreys were stimulated with different immunogens, and lipopolysaccharide (LPS) was found to increase the expression of PKC-δ-like. Overexpression of PKC-δ-like could also effectively activate the innate immune response. We further demonstrated that PKC-δ-like-CF, a catalytic fragment of PKC-δ-like, is responsible for activating the innate immune response, and Thr-211, which is Thr-419 of PKC-δ-like, was confirmed to be the key site affecting PKC-δ-like-CF activity. These results indicated that PKC-δ-like from lamprey may have an important role in the innate immune response.


Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 313
Author(s):  
Daniel Sepulveda-Crespo ◽  
Salvador Resino ◽  
Isidoro Martinez

Despite successful treatments, hepatitis C virus (HCV) infections continue to be a significant world health problem. High treatment costs, the high number of undiagnosed individuals, and the difficulty to access to treatment, particularly in marginalized susceptible populations, make it improbable to achieve the global control of the virus in the absence of an effective preventive vaccine. Current vaccine development is mostly focused on weakly immunogenic subunits, such as surface glycoproteins or non-structural proteins, in the case of HCV. Adjuvants are critical components of vaccine formulations that increase immunogenic performance. As we learn more information about how adjuvants work, it is becoming clear that proper stimulation of innate immunity is crucial to achieving a successful immunization. Several hepatic cell types participate in the early innate immune response and the subsequent inflammation and activation of the adaptive response, principally hepatocytes, and antigen-presenting cells (Kupffer cells, and dendritic cells). Innate pattern recognition receptors on these cells, mainly toll-like receptors, are targets for new promising adjuvants. Moreover, complex adjuvants that stimulate different components of the innate immunity are showing encouraging results and are being incorporated in current vaccines. Recent studies on HCV-vaccine adjuvants have shown that the induction of a strong T- and B-cell immune response might be enhanced by choosing the right adjuvant.


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