Microbial Metalloproteinases Mediate Sensing of Invading Pathogens and Activate Innate Immune Responses in the Lepidopteran Model Host Galleria mellonella

ABSTRACT Thermolysin-like metalloproteinases such as aureolysin, pseudolysin, and bacillolysin represent virulence factors of diverse bacterial pathogens. Recently, we discovered that injection of thermolysin into larvae of the greater wax moth, Galleria mellonella, mediated strong immune responses. Thermolysin-mediated proteolysis of hemolymph proteins yielded a variety of small-sized (<3 kDa) protein fragments (protfrags) that are potent elicitors of innate immune responses. In this study, we report the activation of a serine proteinase cascade by thermolysin, as described for bacterial lipopolysaccharides (LPS), that results in subsequent prophenoloxidase activation leading to melanization, an elementary immune defense reaction of insects. Quantitative real-time reverse transcription-PCR analyses of the expression of immune-related genes encoding the inducible metalloproteinase inhibitor, gallerimycin, and lysozyme demonstrated increased transcriptional rates after challenge with purified protfrags similar to rates after challenge with LPS. Additionally, we determined the induction of a similar spectrum of immune-responsive proteins that were secreted into the hemolymph by using comparative proteomic analyses of hemolymph proteins from untreated larvae and from larvae that were challenged with either protfrags or LPS. Since G. mellonella was recently established as a valuable pathogenicity model for Cryptococcus neoformans infection, the present results add to our understanding of the mechanisms of immune responses in G. mellonella. The obtained results support the proposed danger model, which suggests that the immune system senses endogenous alarm signals during infection besides recognition of microbial pattern molecules.

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A Galleria mellonella Oral Administration Model to Study Commensal-Induced Innate Immune Responses

Journal of Visualized Experiments ◽

10.3791/59270 ◽

2019 ◽

Cited By ~ 1

Author(s):

Anna Lange ◽

Andrea Schäfer ◽

Julia-Stefanie Frick

Keyword(s):

Immune Responses ◽

Oral Administration ◽

Galleria Mellonella ◽

Innate Immune ◽

Innate Immune Responses

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Mycobacterium tuberculosisinhibits human innate immune responses via the production of TLR2 antagonist glycolipids

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1707840114 ◽

2017 ◽

Vol 114 (42) ◽

pp. 11205-11210 ◽

Cited By ~ 33

Author(s):

Landry Blanc ◽

Martine Gilleron ◽

Jacques Prandi ◽

Ok-ryul Song ◽

Mi-Seon Jang ◽

...

Keyword(s):

Immune Responses ◽

Molecular Mechanisms ◽

Cytokine Production ◽

Cell Envelope ◽

Costimulatory Molecule ◽

Immune Defense ◽

Innate Immune ◽

Host Cells ◽

Innate Immune Responses ◽

Reporter System

Mycobacterium tuberculosisis a major human pathogen that is able to survive inside host cells and resist immune clearance. Most particularly, it inhibits several arms of the innate immune response, including phagosome maturation or cytokine production. To better understand the molecular mechanisms by whichM. tuberculosiscircumvents host immune defenses, we used a transposon mutant library generated in a virulent clinical isolate ofM. tuberculosisof the W/Beijing family to infect human macrophages, utilizing a cell line derivative of THP-1 cells expressing a reporter system for activation of the transcription factor NF-κB, a key regulator of innate immunity. We identified severalM. tuberculosismutants inducing a NF-κB activation stronger than that of the wild-type strain. One of these mutants was found to be deficient for the synthesis of cell envelope glycolipids, namely sulfoglycolipids, suggesting that the latter can interfere with innate immune responses. Using natural and synthetic molecular variants, we determined that sulfoglycolipids inhibit NF-κB activation and subsequent cytokine production or costimulatory molecule expression by acting as competitive antagonists of Toll-like receptor 2, thereby inhibiting the recognition ofM. tuberculosisby this receptor. Our study reveals that producing glycolipid antagonists of pattern recognition receptors is a strategy used byM. tuberculosisto undermine innate immune defense. Sulfoglycolipids are major and specific lipids ofM. tuberculosis, considered for decades as virulence factors of the bacilli. Our study uncovers a mechanism by which they may contribute toM. tuberculosisvirulence.

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Innate Immune Responses of Skin Mucosa in Common Carp (Cyprinus Carpio) Fed a Diet Supplemented with Galactooligosaccharides

Animals ◽

10.3390/ani10030438 ◽

2020 ◽

Vol 10 (3) ◽

pp. 438 ◽

Cited By ~ 3

Author(s):

Elzbieta Pietrzak ◽

Jan Mazurkiewicz ◽

Anna Slawinska

Keyword(s):

Gene Expression ◽

Immune Responses ◽

Common Carp ◽

Geometric Mean ◽

Juvenile Fish ◽

Innate Immune ◽

Innate Immune Responses ◽

Immune Related Genes ◽

The Impact ◽

Skin Mucosa

Galactooligosaccharides (GOS) are well-known immunomodulatory prebiotics. We hypothesize that GOS supplemented in feed modulates innate immune responses in the skin-associated lymphoid tissue (SALT) of common carp. The aim of this study was to determine the impact of GOS on mRNA expression of the immune-related genes in skin mucosa. During the feeding trial, the juvenile fish (bodyweight 180 ± 5 g) were fed two types of diet for 50 days: control and supplemented with 2% GOS. At the end of the trial, a subset of fish was euthanized (n = 8). Skin mucosa was collected, and RNA was extracted. Gene expression analysis was performed with RT-qPCR to determine the mRNA abundance of the genes associated with innate immune responses in SALT, i.e., acute-phase protein (CRP), antimicrobial proteins (His2Av and GGGT5L), cytokines (IL1β, IL4, IL8, IL10, and IFNγ), lectin (CLEC4M), lyzosymes (LyzC and LyzG), mucin (M5ACL), peroxidase (MPO), proteases (CTSB and CTSD), and oxidoreductase (TXNL). The geometric mean of 40s s11 and ACTB was used to normalize the data. Relative quantification of the gene expression was calculated with ∆∆Ct. GOS upregulated INFγ (p ≤ 0.05) and LyzG (p ≤ 0.05), and downregulated CRP (p ≤ 0.01). We conclude that GOS modulates innate immune responses in the skin mucosa of common carp.

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Innate Immune Responses to Lung-Stage Helminth Infection Induce Alternatively Activated Alveolar Macrophages

Infection and Immunity ◽

10.1128/iai.00687-06 ◽

2006 ◽

Vol 74 (9) ◽

pp. 4970-4981 ◽

Cited By ~ 103

Author(s):

Joshua J. Reece ◽

Mark C. Siracusa ◽

Alan L. Scott

Keyword(s):

Gene Expression ◽

Innate Immunity ◽

Immune Responses ◽

Alveolar Macrophages ◽

Scid Mice ◽

Innate Immune ◽

Innate Immune Responses ◽

Th2 Immune Response ◽

Genes Encoding ◽

Alternatively Activated

ABSTRACT While it is well established that infection with the rodent hookworm Nippostrongylus brasiliensis induces a strongly polarized Th2 immune response, little is known about the innate host-parasite interactions that lead to the development of this robust Th2 immunity. We exploited the transient pulmonary phase of N. brasiliensis development to study the innate immune responses induced by this helminth parasite in wild-type (WT) and severe-combined immune deficient (SCID) BALB/c mice. Histological analysis demonstrated that the cellular infiltrates caused by N. brasiliensis transit through the lungs were quickly resolved in WT mice but not in SCID mice. Microarray-based gene expression analysis demonstrated that there was a rapid induction of genes encoding molecules that participate in innate immunity and in repair/remodeling during days 2 to 4 postinfection in the lungs of WT and SCID mice. Of particular note was the rapid upregulation in both WT and SCID mice of the genes encoding YM1, FIZZ1, and Arg1, indicating a role for alternatively activated macrophages (AAMs) in pulmonary innate immunity. Immunohistochemistry revealed that nearly all alveolar macrophages became YM1-producing AAMs as early as day 2 postinfection. While the innate responses induced during the lung phase of N. brasiliensis infection were similar in complexity and magnitude in WT and SCID mice, only mice with functional T cells were capable of maintaining elevated levels of gene expression beyond the innate window of reactivity. The induction of alternatively activated alveolar macrophages could be important for dampening the level of inflammation in the lungs and contribute to the long-term decrease in pulmonary inflammation that has been associated with helminth infections.

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Toll-like receptor 10 is involved in induction of innate immune responses to influenza virus infection

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1324266111 ◽

2014 ◽

Vol 111 (10) ◽

pp. 3793-3798 ◽

Cited By ~ 89

Author(s):

Suki M. Y. Lee ◽

Kin-Hang Kok ◽

Martial Jaume ◽

Timothy K. W. Cheung ◽

Tsz-Fung Yip ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Immune Responses ◽

Viral Infection ◽

Influenza Virus Infection ◽

Immune Defense ◽

Innate Immune ◽

Immune Recognition ◽

Innate Immune Responses ◽

Infected Cells

Toll-like receptors (TLRs) play key roles in innate immune recognition of pathogen-associated molecular patterns of invading microbes. Among the 10 TLR family members identified in humans, TLR10 remains an orphan receptor without known agonist or function. TLR10 is a pseudogene in mice and mouse models are noninformative in this regard. Using influenza virus infection in primary human peripheral blood monocyte-derived macrophages and a human monocytic cell line, we now provide previously unidentified evidence that TLR10 plays a role in innate immune responses following viral infection. Influenza virus infection increased TLR10 expression and TLR10 contributed to innate immune sensing of viral infection leading to cytokine induction, including proinflammatory cytokines and interferons. TLR10 induction is more pronounced following infection with highly pathogenic avian influenza H5N1 virus compared with a low pathogenic H1N1 virus. Induction of TLR10 by virus infection requires active virus replication and de novo protein synthesis. Culture supernatants of virus-infected cells modestly up-regulate TLR10 expression in nonvirus-infected cells. Signaling via TLR10 was activated by the functional RNA–protein complex of influenza virus leading to robust induction of cytokine expression. Taken together, our findings identify TLR10 as an important innate immune sensor of viral infection and its role in innate immune defense and immunopathology following viral and bacterial pathogens deserves attention.

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Effects of artificial substrates on the growth and immunology of postlarvae of Marsupenaeus japonicus (Spence Bate, 1888) (Decapoda: Dendrobranchiata: Penaeidae) reared in biofloc

Journal of Crustacean Biology ◽

10.1093/jcbiol/ruab044 ◽

2021 ◽

Vol 41 (3) ◽

Author(s):

Su-Kyoung Kim ◽

In-Kwon Jang ◽

Seok Ryel Kim ◽

Jea Chun Jeon ◽

Su Kyoung Kim

Keyword(s):

Serine Proteinase ◽

Innate Immune ◽

Artificial Substrate ◽

Artificial Substrates ◽

Marsupenaeus Japonicus ◽

Nursery Culture ◽

Reverse Transcription Pcr ◽

Immune Related Genes ◽

And Control ◽

Positive Effect

Abstract We investigated the effects of biofloc and artificial substrates (net and brush) on the growth and immunology of the postlarvae of Marsupenaeus japonicus (Spence Bate, 1888) reared for 30 days. The mRNA expressions of innate immune-related genes (prophenoloxidase, masquerade-like serine proteinase, and lysozyme) in the postlarvae were analyzed using quantitative reverse transcription PCR (qRT-PCR). The highest specific growth rate of larvae (3.66 ± 0.02% d–1, 3.75 ± 0.02% d–1) were shown in the net and control groups. The highest survival rate (90 ± 7.1%) was observed in the brush group (P < 0.05). The net yield was significantly higher in the artificial substrate groups (brush 36.60 ± 6.19 g m–2, net 36.46 ± 2.36 g m–2) than in the control (33.79 ± 0.16 g m–2) (P < 0.05). Total suspended, volatile suspended, and suspended solids were significantly lower in the brush group than in the other groups. The immune-related genes showed significantly higher expressions in the artificial substrate groups than in the control. These results support the benefits of artificial substrate in M. japonicus nursery culture to mitigate space competition and suppress cannibalism, with a positive effect on survival. The additional surface area provided by the biofloc, which the larvae can graze on, enhanced the expression of immune-related genes in individuals.

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Intestinal Innate Immunity to Campylobacter jejuni Results in Induction of Bactericidal Human Beta-Defensins 2 and 3

Infection and Immunity ◽

10.1128/iai.73.11.7281-7289.2005 ◽

2005 ◽

Vol 73 (11) ◽

pp. 7281-7289 ◽

Cited By ~ 57

Author(s):

Matthias Zilbauer ◽

Nick Dorrell ◽

Parjeet K. Boughan ◽

Andrew Harris ◽

Brendan W. Wren ◽

...

Keyword(s):

Immune Responses ◽

Antimicrobial Peptides ◽

Campylobacter Jejuni ◽

Bactericidal Effect ◽

Immune Defense ◽

Innate Immune ◽

Intestinal Epithelial ◽

Innate Immune Responses ◽

Innate Defense ◽

Peptide Expression

ABSTRACT Campylobacter jejuni is the most prevalent cause of bacterial diarrhea worldwide. Despite the serious health problems caused by this bacterium, human innate immune responses to C. jejuni infection remain poorly defined. Human β-defensins, a family of epithelial antimicrobial peptides, are a major component of host innate defense at the gastrointestinal mucosal surface. In this study, the effect of two different C. jejuni wild-type strains on human intestinal epithelial innate responses was investigated. Up-regulation of β-defensin gene and peptide expression during infection was observed and recombinant β-defensins were shown to have a direct bactericidal effect against C. jejuni through disruption of cell wall integrity. Further studies using an isogenic capsule-deficient mutant showed that, surprisingly, the absence of the bacterial polysaccharide capsule did not change the innate immune responses induced by C. jejuni or the ability of C. jejuni to survive exposure to recombinant β-defensins. This study suggests a major role for this family of antimicrobial peptides in the innate immune defense against this human pathogen.

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Oral Immune Activation by Disgust and Disease-Related Pictures

Journal of Psychophysiology ◽

10.1027/0269-8803/a000143 ◽

2015 ◽

Vol 29 (3) ◽

pp. 119-129 ◽

Cited By ~ 4

Author(s):

Richard J. Stevenson ◽

Deborah Hodgson ◽

Megan J. Oaten ◽

Luba Sominsky ◽

Mehmet Mahmut ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Innate Immune Response ◽

Negative Control ◽

Innate Immune ◽

Innate Immune Responses ◽

Immune Markers ◽

Before And After ◽

Secondary Analyses ◽

Image Set

Abstract. Both disgust and disease-related images appear able to induce an innate immune response but it is unclear whether these effects are independent or rely upon a common shared factor (e.g., disgust or disease-related cognitions). In this study we directly compared these two inductions using specifically generated sets of images. One set was disease-related but evoked little disgust, while the other set was disgust evoking but with less disease-relatedness. These two image sets were then compared to a third set, a negative control condition. Using a wholly within-subject design, participants viewed one image set per week, and provided saliva samples, before and after each viewing occasion, which were later analyzed for innate immune markers. We found that both the disease related and disgust images, relative to the negative control images, were not able to generate an innate immune response. However, secondary analyses revealed innate immune responses in participants with greater propensity to feel disgust following exposure to disease-related and disgusting images. These findings suggest that disgust images relatively free of disease-related themes, and disease-related images relatively free of disgust may be suboptimal cues for generating an innate immune response. Not only may this explain why disgust propensity mediates these effects, it may also imply a common pathway.

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