Dataset Information

S. aureus drives expansion of low density neutrophils in the diabetic host

ABSTRACT: Abstract S. aureus is a major opportunistic pathogen infecting patients with diabetes. Increased mortality was observed following IV S. aureus infection in diabetic mice compared to non-diabetic controls, correlating with increased numbers of low density neutrophils (LDNs) and neutrophil extracellular traps (NETs). LDN development is dependent on TGFβ, which was more activated in the diabetic host. Neutralization of TGFβ, or the integrin responsible for its activation α5β8, reduced numbers of LDNs and improved survival. Comparison of high and low density neutrophils identified PTEN signaling as a central regulator of LDN NET release. Inhibition of PTEN improved survival and decreased NET production in infected diabetic mice. MEDI4893*, a monoclonal antibody that neutralizes alpha toxin (AT) in development for prevention of S. aureus infection, was able to block TGFβ activation, reduce LDNs and NETs, and significantly improve survival. Our data identify a population of neutrophils in infected diabetic mice which correlated with decreased survival and increased NET production. Targeting a single virulence factor of S. aureus prevented emergence of the LDN population and improved survival, supporting potential use of pathogen specific antibodies for treating diabetic infections.

OTHER RELATED OMICS DATASETS IN: GSE122195

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Cell Culture, Neutrophil

SUBMITTER: Raghothama Chaerkady

LAB HEAD: Sonja Hess

PROVIDER: PXD012176 | Pride | 2019-04-26

REPOSITORIES: Pride

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Publications

Staphylococcus aureus drives expansion of low-density neutrophils in diabetic mice.

Cohen Taylor S TS Takahashi Virginia V Bonnell Jessica J Tovchigrechko Andrey A Chaerkady Raghothama R Yu Wen W Jones-Nelson Omari O Lee Young Y Raja Rajiv R Hess Sonja S Stover C Kendall CK Worthington John J JJ Travis Mark A MA Sellman Bret R BR

The Journal of clinical investigation 20190415 5

Diabetic individuals are at considerable risk for invasive infection by Staphylococcus aureus, however, the mechanisms underlying this enhanced susceptibility to infection are unclear. We observed increased mortality following i.v. S. aureus infection in diabetic mice compared with nondiabetic controls, correlating with increased numbers of low-density neutrophils (LDNs) and neutrophil extracellular traps (NETs). LDNs have been implicated in the inflammatory pathology of diseases such as lupus, ...[more]

PMID: 30985291

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Project description:Staphylococcus aureus is one of the first and most prevalent pathogens cultured from the airways of cystic fibrosis (CF) patients, which can persist there for extended periods. Airway infections in CF patients are characterized by a strong inflammatory response of highly recruited neutrophils. One killing mechanism of neutrophils is the formation of neutrophil extracellular traps (NETs), which capture and eradicate bacteria by extracellular fibers of neutrophil chromatin decorated with antimicrobial granule proteins. S. aureus secretes nuclease, which can degrade NETs. We hypothesized, that S. aureus adapts to the airways of CF patients during persistent infection by escaping from NET-mediated killing via an increase of nuclease activity. Sputum samples of CF patients with chronic S. aureus infection were visualized by confocal microscopy after immuno-fluorescence staining for NET-specific markers, S. aureus bacteria and overall DNA structures. Nuclease activity was analyzed in sequential isogenic long persisting S. aureus isolates, as confirmed by whole genome sequencing, from an individual CF patient using a FRET-based nuclease activity assay. Additionally, some of these isolates were selected and analyzed by qRT-PCR to determine the expression of nuc1 and regulators of interest. NET-killing assays were performed with clinical S. aureus isolates to evaluate killing and bacterial survival depending on nuclease activity. To confirm the role of nuclease during NET-mediated killing, a clinical isolate with low nuclease activity was transformed with a nuclease expression vector (pCM28nuc). Furthermore, two sputa from an individual CF patient were subjected to RNA-sequence analysis to evaluate the activity of nuclease in vivo. In sputa, S. aureus was associated to extracellular DNA structures. Nuclease activity in clinical S. aureus isolates increased in a time-and phenotype-dependent manner. In the clinical isolates, the expression of nuc1 was inversely correlated to the activity of agr and was independent of saeS. NET-mediated killing was significantly higher in S. aureus isolates with low compared to isolates with high nuclease activity. Importantly, transformation of the clinical isolate with low nuclease activity with pCM28nuc conferred protection against NET-mediated killing confirming the beneficial role of nuclease for protection against NETs. Also, nuclease expression in in vivo sputa was high, which underlines the important role of nuclease within the highly inflamed CF airways. In conclusion, our data show that S. aureus adapts to the neutrophil-rich environment of CF airways with increasing nuclease expression most likely to avoid NET-killing during long-term persistence.

Dataset Information

S. aureus drives expansion of low density neutrophils in the diabetic host

Publications

Staphylococcus aureus drives expansion of low-density neutrophils in diabetic mice.

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