Functional amyloids in insect immune response

Falabella, Patrizia; Riviello, Lea; Pascale, Mariarosa; Lelio, Ilaria Di; Tettamanti, Gianluca; Grimaldi, Annalisa; Iannone, Carla; Monti, Maria; Pucci, Piero; Tamburro, Antonio Mario; deEguileor, Magda; Gigliotti, Silvia; Pennacchio, Francesco

doi:10.1016/j.ibmb.2011.11.011

Cited by 47 publications

(48 citation statements)

References 38 publications

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“…We have recently discovered that in Lepidoptera, regulation of the encapsulation and melanization process is mediated in part by a molecular scaffold composed of amyloid fibers (37), and that the RNAi-mediated silencing of the gene encoding the amyloidogenic protein (102 Sl) disrupts these immune responses (35). Here we have demonstrated that in S. littoralis, the nodulation/suppression of microbes is similarly affected by the silencing of this gene, whereas the phagocytic activity of hemocytes and the humoral antimicrobial response remain unaltered.…”

Section: Discussionmentioning

confidence: 99%

“…This gene is highly expressed in the immune cells circulating in the hemolymph (i.e., hemocytes) and modulates their incorporation in multilayered capsules formed around foreign intruders entering the body cavity (i.e., the hemocoel) (35). The final result is the encapsulation of large objects and the nodulation of bacterial cells or aggregates, which are eventually suppressed by localized production of melanin and other toxic compounds on their surface (36,37).…”

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confidence: 99%

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Midgut microbiota and host immunocompetence underlieBacillus thuringiensiskilling mechanism

Caccia¹,

Lelio

Storia

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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150

128

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Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced nodulation response, which was associated with a significant enhancement of host larvae mortality triggered by B. thuringiensis and a Cry toxin. This was determined by an uncontrolled proliferation of midgut bacteria, after entering the body cavity through toxin-induced epithelial lesions. Consequently, the hemolymphatic microbiota dramatically changed upon treatment with Cry1Ca toxin, showing a remarkable predominance of Serratia and Clostridium species, which switched from asymptomatic gut symbionts to hemocoelic pathogens. These experimental results demonstrate the important contribution of host enteric flora in B. thuringiensis-killing activity and provide a sound foundation for developing new insect control strategies aimed at enhancing the impact of biocontrol agents by reducing the immunocompetence of the host.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Midgut microbiota and host immunocompetence underlieBacillus thuringiensiskilling mechanism

Caccia¹,

Lelio

Storia

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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150

128

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“…Moreover, although the processes of clotting and of nodule and capsule formation differ in their final appearance, they share some molecular steps, and both involve melanin biosynthesis (24)(25)(26). Among the immune genes involved in these reactions is a sequence of key importance codes for a protein generating amyloid fibers that mediate encapsulation and strictly localized melanization of nonself material in Lepidoptera (27,28). Here we cloned and characterized the cDNA of the homolog of this gene in Apis mellifera (GenBank accession no.…”

Section: Dwv Infection and Honey Bee Immunosuppressionmentioning

confidence: 99%

“…KU513387), hereinafter denoted as Amel\102. This full-length cDNA encodes a predicted protein of 270 aa that shows 36% sequence identity with P102Hv (27) (Fig. S1).…”

Section: Dwv Infection and Honey Bee Immunosuppressionmentioning

confidence: 99%

A mutualistic symbiosis between a parasitic mite and a pathogenic virus undermines honey bee immunity and health

Prisco

Annoscia

Margiotta

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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217

228

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Honey bee colony losses are triggered by interacting stress factors consistently associated with high loads of parasites and/or pathogens. A wealth of biotic and abiotic stressors are involved in the induction of this complex multifactorial syndrome, with the parasitic mite Varroa destructor and the associated deformed wing virus (DWV) apparently playing key roles. The mechanistic basis underpinning this association and the evolutionary implications remain largely obscure. Here we narrow this research gap by demonstrating that DWV, vectored by the Varroa mite, adversely affects humoral and cellular immune responses by interfering with NF-κB signaling. This immunosuppressive effect of the viral pathogen enhances reproduction of the parasitic mite. Our experimental data uncover an unrecognized mutualistic symbiosis between Varroa and DWV, which perpetuates a loop of reciprocal stimulation with escalating negative effects on honey bee immunity and health. These results largely account for the remarkable importance of this mite-virus interaction in the induction of honey bee colony losses. The discovery of this mutualistic association and the elucidation of the underlying regulatory mechanisms sets the stage for a more insightful analysis of how synergistic stress factors contribute to colony collapse, and for the development of new strategies to alleviate this problem.Apis mellifera | Varroa destructor | deformed wing virus | mutualistic symbiosis | honeybee colony losses

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“…[37][38][39][40] The NLRP3 inflammasome, associated with immune responses to CNTs, [27][28][29][30]41 activates release of IL-18, 42 a cytokine associated with amyloid plaque formation in Alzheimer's disease, [43][44][45][46] a neurodegenerative disorder characterized by amyloid accumulation. For these reasons, we investigated the ability of CNTs to induce amyloid production and deposition in vivo, an innate defense mechanism present in most eukaryotic phyla ranging from fungi and invertebrates [47][48][49] to humans. 50 We evaluated the effects of CNTs exposure in a murine model reflecting MWCNTs exposure in the environment.…”

Section: Introductionmentioning

confidence: 99%

Environmental impact of multi-wall carbon nanotubes in a novel model of exposure: systemic distribution, macrophage accumulation, and amyloid deposition

Albini¹,

Pagani²,

Pulze³

et al. 2015

IJN

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Carbon nanotubes (CNTs) have been extensively investigated and employed for industrial use because of their peculiar physical properties, which make them ideal for many industrial applications. However, rapid growth of CNT employment raises concerns about the potential risks and toxicities for public health, environment, and workers associated with the manufacture and use of these new materials. Here we investigate the main routes of entry following environmental exposure to multi-wall CNTs (MWCNTs; currently the most widely used in industry). We developed a novel murine model that could represent a surrogate of a workplace exposure to MWCNTs. We traced the localization of MWCNTs and their possible role in inducing an innate immune response, inflammation, macrophage recruitment, and inflammatory conditions. Following environmental exposure of CD1 mice, we observed that MWCNTs rapidly enter and disseminate in the organism, initially accumulating in lungs and brain and later reaching the liver and kidney via the bloodstream. Since recent experimental studies show that CNTs are associated with the aggregation process of proteins associated with neurodegenerative diseases, we investigated whether MWCNTs are able to induce amyloid fibril production and accumulation. Amyloid deposits in spatial association with macrophages and MWCNT aggregates were found in the brain, liver, lungs, and kidneys of exposed animals. Our data suggest that accumulation of MWCNTs in different organs is associated with inflammation and amyloid accumulation. In the brain, where we observed rapid accumulation and amyloid fibril deposition, exposure to MWCNTs might enhance progression of neurodegenerative and other amyloid-related diseases. Our data highlight the conclusion that, in a novel rodent model of exposure, MWCNTs may induce macrophage recruitment, activation, and amyloid deposition, causing potential damage to several organs.

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Functional amyloids in insect immune response

Cited by 47 publications

References 38 publications

Midgut microbiota and host immunocompetence underlieBacillus thuringiensiskilling mechanism

Midgut microbiota and host immunocompetence underlieBacillus thuringiensiskilling mechanism

A mutualistic symbiosis between a parasitic mite and a pathogenic virus undermines honey bee immunity and health

Environmental impact of multi-wall carbon nanotubes in a novel model of exposure: systemic distribution, macrophage accumulation, and amyloid deposition

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