Different paths to pathogenesis

Allen, Jonathan P.; Ozer, Egon A.; Hauser, Alan R.

doi:10.1016/j.tim.2014.02.013

Cited by 5 publications

(5 citation statements)

References 10 publications

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“…Two major groups with active T3SS express either ExoS or ExoU exoenzymes to provoke cytotoxicity toward eukaryotic cell, with ExoS displaying GTPase activating and ADP‐ribosyltransferase activities and ExoU being a phospholipase (Vallis et al ., ; Sato et al ., ; Hauser, ). On the other hand, a minor group of strains lacks T3SS but uses ExlA, a recently identified TPS pore‐forming toxin (Allen et al ., ; Elsen et al ., ). To further gain knowledge on the characteristics of eukaryotic cell death triggered by ExlA, we developed a robust, reproducible high‐throughput method to assess the kinetics of bacteria‐induced macrophage death by live cellular imaging using a high‐content (HC) microscope system.…”

Section: Resultsmentioning

confidence: 99%

Multiple Pseudomonas species secrete exolysin‐like toxins and provoke Caspase‐1‐dependent macrophage death

Basso

Wallet

Elsen

et al. 2017

Environmental Microbiology

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Pathogenic bacteria secrete protein toxins that provoke apoptosis or necrosis of eukaryotic cells. Here, we developed a live-imaging method, based on incorporation of a DNA-intercalating dye into membrane-damaged host cells, to study the kinetics of primary bone marrow-derived macrophages (BMDMs) mortality induced by opportunistic pathogen Pseudomonas aeruginosa expressing either Type III Secretion System (T3SS) toxins or the pore-forming toxin, Exolysin (ExlA). We found that ExlA promotes the activation of Caspase-1 and maturation of interleukin-1β. BMDMs deficient for Caspase-1 and Caspase-11 were resistant to ExlA-induced death. Furthermore, by using KO BMDMs, we determined that the upstream NLRP3/ASC complex leads to the Caspase-1 activation. We also demonstrated that Pseudomonas putida and Pseudomonas protegens and the Drosophila pathogen Pseudomonas entomophila, which naturally express ExlA-like toxins, are cytotoxic toward macrophages and provoke the same type of pro-inflammatory death as does ExlA P. aeruginosa. These results demonstrate that ExlA-like toxins of two-partner secretion systems from diverse Pseudomonas species activate the NLRP3 inflammasome and provoke inflammatory pyroptotic death of macrophages.

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Section: Resultsmentioning

confidence: 99%

Multiple Pseudomonas species secrete exolysin‐like toxins and provoke Caspase‐1‐dependent macrophage death

Basso

Wallet

Elsen

et al. 2017

Environmental Microbiology

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“…Similarly, virulent strains of S. epidermidis differ from nonvirulent strains by a four-gene operon involved in biofilm formation and an insertion sequence element, genetic changes that may be associated with horizontal gene transfer (HGT) events (73). In general, virulence potential may be a shallow trait, as it often appears to evolve independently via HGT-for instance, among mi-crobes such as Escherichia coli (74) and Pseudomonas aeruginosa (75).…”

Section: Trait Conservatism and Biogeographymentioning

confidence: 99%

Microbiomes in light of traits: A phylogenetic perspective

Martiny

Jones

Lennon

et al. 2015

Science

698

621

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A focus on the phenotypic characteristics of microorganisms-their traits-offers a path for interpreting the growing amount of microbiome data. We review key aspects of microbial traits, as well as approaches used to assay their phylogenetic distribution. Recent studies reveal that microbial traits are differentially conserved across the tree of life and appear to be conserved in a hierarchical fashion, possibly linked to their biochemical complexity. These results suggest a predictive framework whereby the genetic (or taxonomic) resolution of microbiome variation among samples provides information about the traits under selection. The organizational parallels seen among human and free-living microbiomes seem to support this idea. Developments in this framework may offer predictions not only for how microbial composition responds to changing environmental conditions, but also for how these changes may alter the health or functioning in human, engineered, and environmental systems.

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“…Pseudomonas aeruginosa is an opportunistic pathogen that has been emerging as a primary source of nosocomial infections, and can cause urinary and respiratory tract infections, soft tissue infections, endocarditis, and a variety of systemic infections, particularly in burned patients, with cancer, cystic fibrosis, or compromised immune systems (Giamarellou, 2002;Inglis et al, 2010;Luna et al, 2013;Allen et al, 2014).…”

Section: Introductionmentioning

confidence: 99%