Conditioning Protects C. elegans from Lethal Effects of Enteropathogenic E. coli by Activating Genes that Regulate Lifespan and Innate Immunity

Background: The antidepressant mianserin has been shown to extend the lifespan of Caenorhabditis elegans (C. elegans), a well-established model organism used in aging research. The extension of lifespan in C. elegans was shown to be dependent on increased expression of the scaffolding protein (ANK3/unc-44). In contrast, antidepressant use in humans is associated with an increased risk of death. The C. elegans in the laboratory are fed Escherichia coli (E. coli), a diet high in protein and low in carbohydrate, whereas a typical human diet is high in carbohydrates. We hypothesized that dietary carbohydrates might mitigate the lifespan-extension effect of mianserin. Objective: To investigate the effect of glucose added to the diet of C. elegans on the lifespan-extension effect of mianserin. Methods: Wild-type Bristol N2 and ANK3/unc-44 inactivating mutants were cultured on agar plates containing nematode growth medium and fed E. coli. Treatment groups included (C) control, (M50) 50 μM mianserin, (G) 73 mM glucose, and (M50G) 50 μM mianserin and 73 mM glucose. Lifespan was determined by monitoring the worms until they died. Statistical analysis was performed using the Kaplan-Meier version of the log-rank test. Results: Mianserin treatment resulted in a 12% increase in lifespan (P<0.05) of wild-type Bristol N2 worms but reduced lifespan by 6% in ANK3/unc-44 mutants, consistent with previous research. The addition of glucose to the diet reduced the lifespan of both strains of worms and abolished the lifespan-extension by mianserin. Conclusion: The addition of glucose to the diet of C. elegans abolishes the lifespan-extension effects of mianserin.

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Iron Acquisition of Urinary Tract Infection Escherichia coli Involves Pathogenicity in Caenorhabditis elegans

Microorganisms ◽

10.3390/microorganisms9020310 ◽

2021 ◽

Vol 9 (2) ◽

pp. 310

Author(s):

Masayuki Hashimoto ◽

Yi-Fen Ma ◽

Sin-Tian Wang ◽

Chang-Shi Chen ◽

Ching-Hao Teng

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Caenorhabditis Elegans ◽

Large Scale ◽

Iron Acquisition ◽

Infection Model ◽

High Throughput Analysis ◽

E Coli ◽

C Elegans ◽

Tract Infections

Uropathogenic Escherichia coli (UPEC) is a major bacterial pathogen that causes urinary tract infections (UTIs). The mouse is an available UTI model for studying the pathogenicity; however, Caenorhabditis elegans represents as an alternative surrogate host with the capacity for high-throughput analysis. Then, we established a simple assay for a UPEC infection model with C. elegans for large-scale screening. A total of 133 clinically isolated E. coli strains, which included UTI-associated and fecal isolates, were applied to demonstrate the simple pathogenicity assay. From the screening, several virulence factors (VFs) involved with iron acquisition (chuA, fyuA, and irp2) were significantly associated with high pathogenicity. We then evaluated whether the VFs in UPEC were involved in the pathogenicity. Mutants of E. coli UTI89 with defective iron acquisition systems were applied to a solid killing assay with C. elegans. As a result, the survival rate of C. elegans fed with the mutants significantly increased compared to when fed with the parent strain. The results demonstrated, the simple assay with C. elegans was useful as a UPEC infectious model. To our knowledge, this is the first report of the involvement of iron acquisition in the pathogenicity of UPEC in a C. elegans model.

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A Pathoadaptive Deletion in an Enteroaggregative Escherichia coli Outbreak Strain Enhances Virulence in a Caenorhabditis elegans Model

Infection and Immunity ◽

10.1128/iai.00014-10 ◽

2010 ◽

Vol 78 (9) ◽

pp. 4068-4076 ◽

Cited By ~ 11

Author(s):

Jennifer Hwang ◽

Lisa M. Mattei ◽

Laura G. VanArendonk ◽

Philip M. Meneely ◽

Iruka N. Okeke

Keyword(s):

Escherichia Coli ◽

Caenorhabditis Elegans ◽

Epithelial Cells ◽

Genetic Material ◽

Decarboxylase Activity ◽

Multicopy Plasmid ◽

Lysine Decarboxylase ◽

Outbreak Strain ◽

E Coli ◽

C Elegans

ABSTRACT Enteroaggregative Escherichia coli (EAEC) strains are important diarrheal pathogens. EAEC strains are defined by their characteristic stacked-brick pattern of adherence to epithelial cells but show heterogeneous virulence and have different combinations of adhesin and toxin genes. Pathoadaptive deletions in the lysine decarboxylase (cad) genes have been noted among hypervirulent E. coli subtypes of Shigella and enterohemorrhagic E. coli. To test the hypothesis that cad deletions might account for heterogeneity in EAEC virulence, we developed a Caenorhabditis elegans pathogenesis model. Well-characterized EAEC strains were shown to colonize and kill C. elegans, and differences in virulence could be measured quantitatively. Of 49 EAEC strains screened for lysine decarboxylase activity, 3 tested negative. Most notable is isolate 101-1, which was recovered in Japan, from the largest documented EAEC outbreak. EAEC strain 101-1 was unable to decarboxylate lysine in vitro due to deletions in cadA and cadC, which, respectively, encode lysine decarboxylase and a transcriptional activator of the cadAB genes. Strain 101-1 was significantly more lethal to C. elegans than control strain OP50. Lethality was attenuated when the lysine decarboxylase defect was complemented from a multicopy plasmid and in single copy. In addition, restoring lysine decarboxylase function produced derivatives of 101-1 deficient in aggregative adherence to cultured human epithelial cells. Lysine decarboxylase inactivation is pathoadapative in an important EAEC outbreak strain, and deletion of cad genes could produce hypervirulent EAEC lineages in the future. These results suggest that loss, as well as gain, of genetic material can account for heterogeneous virulence among EAEC strains.

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Deficiency of innate immunity against P. aeruginosa enhances behavioral avoidance via the HECW-1/NPR-1 module in C. elegans

Infection and Immunity ◽

10.1128/iai.00067-21 ◽

2021 ◽

Author(s):

Hua Bai ◽

Wei Zou ◽

Wenhui Zhou ◽

Keqin Zhang ◽

Xiaowei Huang

Keyword(s):

Innate Immunity ◽

Pathogenic Bacteria ◽

Immune Gene ◽

Biological Processes ◽

Defensive Strategy ◽

C Elegans ◽

Defensive Strategies ◽

Behavioral Avoidance ◽

Neuropeptide Y Receptor ◽

G Protein Coupled

To antagonize infection of pathogenic bacteria in soil and confer increased survival, Caenorhabditis elegans employs innate immunity and behavioral avoidance synchronously as the two main defensive strategies. Although both biological processes and their individual signaling pathways have been partially elucidated, knowledge of their interrelationship remains limited. The current study reveals that deficiency of innate immunity triggered by mutation of the classic immune gene pmk-1 promotes avoidance behavior in C. elegans ; and vice versa. Restoration of pmk-1 expression using the tissue-specific promoters suggested that the functional loss of both intestinal and neuronal pmk-1 is necessary for the enhanced avoidance. Additionally, PMK-1 co-localized with the E3 ubiquitin ligase HECW-1 in OLL neurons and regulated the expressional level of the latter, which consequently affected the production of NPR-1, a G-protein-coupled receptor homologous to the mammalian neuropeptide Y receptor, in RMG neurons in a non-cell-autonomous manner. Collectively, our study illustrates, once the innate immunity is impaired when C. elegans antagonizes bacterial infection, the other defensive strategy of behavioral avoidance can be enhanced accordingly via the HECW-1/NPR-1 module, suggesting that GPCRs in neural circuits may receive the inputs from immune system and integrate those two systems for better adapting to the real-time status.

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Zebrafish nephrosin helps host defence against Escherichia coli infection

Open Biology ◽

10.1098/rsob.170040 ◽

2017 ◽

Vol 7 (8) ◽

pp. 170040 ◽

Cited By ~ 3

Author(s):

Qianqian Di ◽

Qing Lin ◽

Zhibin Huang ◽

Yali Chi ◽

Xiaohui Chen ◽

...

Keyword(s):

Escherichia Coli ◽

Innate Immunity ◽

Host Defence ◽

Bacterial Burden ◽

Wild Type ◽

Lower Survival Rate ◽

E Coli ◽

Escherichia Coli Infection ◽

Effective Models

Neutrophils play important roles in innate immunity and are mainly dependent on various enzyme-containing granules to kill engulfed microorganisms. Zebrafish nephrosin ( npsn ) is specifically expressed in neutrophils; however, its function is largely unknown. Here, we generated an npsn mutant ( npsn smu5 ) via CRISPR/Cas9 to investigate the in vivo function of Npsn. The overall development and number of neutrophils remained unchanged in npsn -deficient mutants, whereas neutrophil antibacterial function was defective. Upon infection with Escherichia coli , the npsn smu5 mutants exhibited a lower survival rate and more severe bacterial burden, as well as augmented inflammatory response to challenge with infection when compared with wild-type embryos, whereas npsn -overexpressing zebrafish exhibited enhanced host defence against E. coli infection. These findings demonstrated that zebrafish Npsn promotes host defence against bacterial infection. Furthermore, our findings suggested that npsn -deficient and -overexpressing zebrafish might serve as effective models of in vivo innate immunity.

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The DBL-1/TGF-β signaling pathway regulates pathogen-specific innate immune responses in C. elegans

10.1101/2021.03.30.437693 ◽

2021 ◽

Author(s):

Bhoomi Madhu ◽

Tina L. Gumienny

Keyword(s):

Innate Immunity ◽

Immune Responses ◽

Signaling Pathway ◽

Defense Responses ◽

C Elegans ◽

Host Immune Responses ◽

Wide Range ◽

Independent Functions ◽

Multiple Cell

Innate immunity in animals is orchestrated by multiple cell signaling pathways, including the TGF-β; superfamily pathway. While the role of TGF-β signaling in innate immunity has been clearly identified, the requirement for this pathway in generating specific, robust responses to different bacterial challenges has not been characterized. Here, we address the role of DBL-1/TGF-β in regulating signature host defense responses to a wide range of bacteria in C. elegans. This work reveals a role of DBL-1/TGF-β in animal survival, organismal behaviors, and molecular responses in different environments. Additionally, we identify a novel role for SMA-4/Smad that suggests both DBL-1/TGF-β-dependent and -independent functions in host avoidance responses. RNA-seq analyses and immunity reporter studies indicate DBL-1/TGF-β differentially regulates target gene expression upon exposure to different bacteria. Furthermore, the DBL-1/TGF-β pathway is itself differentially affected by the bacteria exposure. Collectively, these findings demonstrate bacteria-specific host immune responses regulated by the DBL-1/TGF-β signaling pathway.

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E. coli OxyS non-coding RNA does not trigger RNAi in C. elegans

10.1101/013029 ◽

2014 ◽

Author(s):

Alper Akay ◽

Peter Sarkies ◽

Eric Alexander Miska

Keyword(s):

Small Rnas ◽

Biological Function ◽

Rapid Development ◽

Rnai Pathway ◽

Regulate Gene Expression ◽

Double Stranded Rna ◽

E Coli ◽

C Elegans ◽

Non Coding Rna ◽

Rnai Response

The discovery of RNA interference (RNAi) in C. elegans has had a major impact on scientific research, led to the rapid development of RNAi tools and has inspired RNA-based therapeutics. Astonishingly, nematodes, planaria and many insects take up double-stranded RNA (dsRNA) from their environment to elicit RNAi; the biological function of this mechanism is unclear. Recently, the E. coli OxyS non-coding RNA was shown to regulate gene expression in C. elegans when E. coli is offered as food. This was surprising given that C. elegans is unlikely to encounter E. coli in nature. To directly test the hypothesis that the E. coli OxyS non-coding RNA triggers the C. elegans RNAi pathway, we sequenced small RNAs from C. elegans after feeding with bacteria. We clearly demonstrate that the OxyS non-coding RNA does not trigger an RNAi response in C. elegans. We conclude that the biology of environmental RNAi remains to be discovered.

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The neuropeptide receptor NMUR-1 regulates the specificity of C. elegans innate immunity against pathogen infection

10.1101/2021.05.06.442992 ◽

2021 ◽

Author(s):

Phillip Wibisono ◽

Shawndra Wibisono ◽

Jan Watteyne ◽

Chia-Hui Chen ◽

Durai Sellegounder ◽

...

Keyword(s):

Innate Immunity ◽

Immune System ◽

Immune Responses ◽

Adaptive Immune System ◽

Innate Immune ◽

Innate Immune Responses ◽

Immune Genes ◽

C Elegans ◽

Adaptive Immune ◽

Functional Assays

A key question in current immunology is how the innate immune system generates high levels of specificity. Like most invertebrates, Caenorhabditis elegans does not have an adaptive immune system and relies solely on innate immunity to defend itself against pathogen attacks, yet it can still differentiate different pathogens and launch distinct innate immune responses. Here, we have found that functional loss of NMUR-1, a neuronal GPCR homologous to mammalian receptors for the neuropeptide neuromedin U, has diverse effects on C. elegans survival against various bacterial pathogens. Transcriptomic analyses and functional assays revealed that NMUR-1 modulates C. elegans transcription activity by regulating the expression of transcription factors, which, in turn, controls the expression of distinct immune genes in response to different pathogens. Our study has uncovered a molecular basis for the specificity of C. elegans innate immunity that could provide mechanistic insights into understanding the specificity of vertebrate innate immunity.

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BIR‐2 is a Critical Component of Innate Immunity in C. elegans

The FASEB Journal ◽

10.1096/fasebj.2021.35.s1.03443 ◽

2021 ◽

Vol 35 (S1) ◽

Author(s):

Annabel Lee ◽

Antonio Rua ◽

Shallee Page

Keyword(s):

Innate Immunity ◽

Critical Component ◽

C Elegans

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