Bacterial lipids: powerful modifiers of the innate immune response

Chandler, Courtney E.; Ernst, Robert K.

doi:10.12688/f1000research.11388.1

Cited by 77 publications

(58 citation statements)

References 59 publications

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“…(C) Extracellular DNA was quantified after extraction from a 5-ml culture (n ϭ 6). Additional extracellular DNA measurements are in initiated that converges on the transcription factor NF-B and subsequent upregulation of inflammatory cytokines and other immunomodulators (51). TLR4 stimulation was assessed using HEK reporter cells transfected with human or murine TLR4, with NF-B activation as the readout.…”

Section: Figmentioning

confidence: 99%

Genomic and Phenotypic Diversity among Ten Laboratory Isolates of Pseudomonas aeruginosa PAO1

et al. 2019

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Pseudomonas aeruginosa is an opportunistic pathogen found ubiquitously in the environment and commonly associated with airway infection in patients with cystic fibrosis. P. aeruginosa strain PAO1 is one of the most commonly used laboratory-adapted research strains and is a standard laboratory-adapted strain in multiple laboratories and strain banks worldwide. Due to potential isolate-to-isolate variability, we investigated the genomic and phenotypic diversity among 10 PAO1 strains (henceforth called sublines) obtained from multiple research laboratories and commercial sources. Genomic analysis predicted a total of 5,682 genes, with 5,434 (95.63%) being identical across all 10 strains. Phenotypic analyses revealed comparable growth phenotypes in rich media and biofilm formation profiles. Limited differences were observed in antibiotic susceptibility profiles and immunostimulatory potential, measured using heat-killed whole-cell preparations in four immortalized cell lines followed by quantification of interleukin-6 (IL-6) and IL-1β secretion. However, variability was observed in the profiles of secreted molecular products, most notably, in rhamnolipid, pyoverdine, pyocyanin, Pseudomonas quinolone signal (PQS), extracellular DNA, exopolysaccharide, and outer membrane vesicle production. Many of the observed phenotypic differences did not correlate with subline-specific genetic changes, suggesting alterations in transcriptional and translational regulation. Taken together, these results suggest that individually maintained sublines of PAO1, even when acquired from the same parent subline, are continuously undergoing microevolution during culture and storage that results in alterations in phenotype, potentially affecting the outcomes of in vitro phenotypic analyses and in vivo pathogenesis studies. IMPORTANCE Laboratory-adapted strains of bacteria are used throughout the world for microbiology research. These prototype strains help keep research data consistent and comparable between laboratories. However, we have observed phenotypic variability when using different strains of Pseudomonas aeruginosa PAO1, one of the major laboratory-adopted research strains. Here, we describe the genomic and phenotypic differences among 10 PAO1 strains acquired from independent sources over 15 years to understand how individual maintenance affects strain characteristics. We observed limited genomic changes but variable phenotypic changes, which may have consequences for cross-comparison of data generated using different PAO1 strains. Our research highlights the importance of limiting practices that may promote the microevolution of model strains and calls for researchers to specify the strain origin to ensure reproducibility.

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Section: Figmentioning

confidence: 99%

Genomic and Phenotypic Diversity among Ten Laboratory Isolates of Pseudomonas aeruginosa PAO1

et al. 2019

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“…When LPS or LTA is released by bacteria (due to bacterial cell division or death), these components, called pathogen‐associated molecular patterns, are recognized by pattern recognition receptors such as the toll like receptor (TLR). Pattern recognition receptors are expressed on cells of the innate immune system and upon activation a cascade of signalling begins, resulting in pro‐inflammatory transcription factors and upregulation of genes controlling the host immune response (Chandler & Ernst, ). The outcome is increased phagocytosis and the release of pro‐inflammatory cytokines, namely TNF and IL‐6 (Rosenfeld & Shai, ).…”

Section: Discussionmentioning

confidence: 99%

“…In this study, whole blood was stimulated with LPS, LTA or PBS controlling the host immune response (Chandler & Ernst, 2017). The outcome is increased phagocytosis and the release of pro-inflammatory cytokines, namely TNF and IL-6 (Rosenfeld & Shai, 2006).…”

Section: Discussionmentioning

confidence: 99%

Dogs with osteosarcoma have altered pro‐ and anti‐inflammatory cytokine profiles

Axiak‐Bechtel

Mathew

Amorim

et al. 2019

Veterinary Medicine & Sci

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BackgroundCurrent advances in immunotherapy are an exciting area of study in canine osteosarcoma (OSA). The objective of this study was to determine the immune response in dogs with osteosarcoma by measuring stimulated leukocyte production of tumor necrosis factor (TNF), interleukin (IL)‐6, IL‐10 and TNF and IL‐6 to IL‐10 ratios.MethodsWhole blood was collected from dogs with osteosarcoma receiving non‐steroidal anti‐inflammatory drugs (NSAIDs, n = 11), dogs with osteosarcoma not receiving NSAIDs (n = 14) and healthy dogs (n = 5).ResultsNo difference in TNF production was found among healthy and OSA dogs regardless of NSAID administration following stimulation with lipopolysaccharide (LPS) (p = .410), lipoteichoic acid (LTA) (p = .693) or PBS (p = .120). Leukocyte IL‐6 production was greater in all dogs with OSA after stimulation with LPS (p = .015), LTA (p = .014) and PBS (p = .034) with no difference between OSA dogs receiving NSAIDs and those not. No differences in IL‐10 were found among healthy controls and dogs with OSA regardless of NSAID use. There was no difference among groups for LPS‐stimulated TNF to IL‐10 ratios (p = .407). For LTA‐stimulated leukocytes, the TNF to IL‐10 ratio was lower in dogs with OSA than in healthy dogs (p = .031) with no difference between OSA NSAID dogs compared to OSA non‐NSAID dogs (p = .059). No differences were found in LPS (p = .310)‐ or LTA (p = .265)‐stimulated leukocyte IL‐6 to IL‐10 production ratios among groups.ConclusionsDogs with osteosarcoma have an altered pro‐ and anti‐inflammatory immunologic profile compared to healthy dogs regardless of NSAID use. Further study is indicated to determine the potential prognostic and therapeutic implications of these findings.

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“…There is evidence to suggest that even if the origin of bacterial products or cell‐free DNA originate from dead or viable but not non‐cultivable bacterial cells, this can still elicit a physiological inflammatory response in the host . Short bacterial DNA fragments ranging in length from five to greater than 900 nucleotides are capable of immune cell activation and cytokine release associated with microbial invasion of the amniotic cavity, chorioamnionitis, preterm pre‐labour rupture of membranes, endometritis, and intrauterine device‐related genital tract infection …”

Section: Methodological Considerations In the Reproductive Tract Micrmentioning

confidence: 99%

Re‐assessing microbiomes in the low‐biomass reproductive niche

Turner

Nitert

et al. 2019

BJOG

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The female reproductive tract represents a continuum between the vagina and the upper genital tract. New evidence from cultivation‐independent studies suggests that the female upper genital tract is not sterile; however, the significance of this for reproductive health and disease remains to be elucidated fully. Further, diagnosis and treatment of infectious reproductive tract pathologies using cultivation‐independent technologies represents a largely unchartered area of modern medical science. The challenge now is to design well‐controlled experiments to account for the ease of contamination known to confound molecular‐based studies of low‐biomass niches, including the uterus and placenta. This will support robust assessment of the potential function of microorganisms, microbial metabolites, and cell‐free bacterial DNA on reproductive function in health and disease. Tweetable abstract Molecular microbial studies of low‐biomass niches require stringent experimental controls to reveal causal relations in reproductive health and disease.

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Bacterial lipids: powerful modifiers of the innate immune response

Cited by 77 publications

References 59 publications

Genomic and Phenotypic Diversity among Ten Laboratory Isolates of Pseudomonas aeruginosa PAO1

Genomic and Phenotypic Diversity among Ten Laboratory Isolates of Pseudomonas aeruginosa PAO1

Dogs with osteosarcoma have altered pro‐ and anti‐inflammatory cytokine profiles

Re‐assessing microbiomes in the low‐biomass reproductive niche

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