Dataset Information

Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system.

ABSTRACT: Bacteria have to avoid recognition by the host immune system in order to establish a successful infection. Peptidoglycan, the principal constituent of virtually all bacterial surfaces, is a specific molecular signature recognized by dedicated host receptors, present in animals and plants, which trigger an immune response. Here we report that autolysins from Gram-positive pathogenic bacteria, enzymes capable of hydrolyzing peptidoglycan, have a major role in concealing this inflammatory molecule from Drosophila peptidoglycan recognition proteins (PGRPs). We show that autolysins trim the outermost peptidoglycan fragments and that in their absence bacterial virulence is impaired, as PGRPs can directly recognize leftover peptidoglycan extending beyond the external layers of bacterial proteins and polysaccharides. The activity of autolysins is not restricted to the producer cells but can also alter the surface of neighboring bacteria, facilitating the survival of the entire population in the infected host. DOI: http://dx.doi.org/10.7554/eLife.02277.001.

SUBMITTER: Atilano ML

PROVIDER: S-EPMC3971415 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature

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Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system.

Atilano Magda Luciana ML Pereira Pedro Matos PM Vaz Filipa F Catalão Maria João MJ Reed Patricia P Grilo Inês Ramos IR Sobral Rita Gonçalves RG Ligoxygakis Petros P Pinho Mariana Gomes MG Filipe Sérgio Raposo SR

eLife 20140401

Bacteria have to avoid recognition by the host immune system in order to establish a successful infection. Peptidoglycan, the principal constituent of virtually all bacterial surfaces, is a specific molecular signature recognized by dedicated host receptors, present in animals and plants, which trigger an immune response. Here we report that autolysins from Gram-positive pathogenic bacteria, enzymes capable of hydrolyzing peptidoglycan, have a major role in concealing this inflammatory molecule ...[more]

PMID: 24692449

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Project description:Coupling immunity and development is essential to ensure survival despite changing internal conditions in the organism. Drosophila metamorphosis represents a striking example of drastic and systemic physiological changes that need to be integrated with the innate immune system. However, nothing is known about the mechanisms that coordinate development and immune cell activity in the transition from larva to adult. Here, we reveal that regulation of macrophage-like cells (hemocytes) by the steroid hormone ecdysone is essential for an effective innate immune response over metamorphosis. Although it is generally accepted that steroid hormones impact immunity in mammals, their action on monocytes (e.g. macrophages and neutrophils) is still not well understood. Here in a simpler model system, we used an approach that allows in vivo, cell autonomous analysis of hormonal regulation of innate immune cells, by combining genetic manipulation with flow cytometry, high-resolution time-lapse imaging and tissue-specific transcriptomic analysis. We show that in response to ecdysone, hemocytes rapidly upregulate actin dynamics, motility and phagocytosis of apoptotic corpses, and acquire the ability to chemotax to damaged epithelia. Most importantly, individuals lacking ecdysone-activated hemocytes are defective in bacterial phagocytosis and are fatally susceptible to infection by bacteria ingested at larval stages, despite the normal systemic and local production of antimicrobial peptides. This decrease in survival is comparable to the one observed in pupae lacking immune cells altogether, indicating that ecdysone-regulation is essential for hemocyte immune functions and survival after infection. Microarray analysis of hemocytes revealed a large set of genes regulated at metamorphosis by EcR signaling, among which many are known to function in cell motility, cell shape or phagocytosis. This study demonstrates an important role for steroid hormone regulation of immunity in vivo in Drosophila, and paves the way for genetic dissection of the mechanisms at work behind steroid regulation of innate immune cells.

Dataset Information

Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system.

Publications

Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system.

Similar Datasets

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