Dataset Information

Vitamin C: a novel regulator of neutrophil extracellular trap formation.

ABSTRACT:

Introduction

Neutrophil extracellular trap (NET) formation was recently identified as a novel mechanism to kill pathogens. However, excessive NET formation in sepsis can injure host tissues. We have recently shown that parenteral vitamin C (VitC) is protective in sepsis. Whether VitC alters NETosis is unknown.

Methods

We used Gulo-/- mice as they lack the ability to synthesize VitC. Sepsis was induced by intraperitoneal infusion of a fecal stem solution (abdominal peritonitis, FIP). Some VitC deficient Gulo-/- mice received an infusion of ascorbic acid (AscA, 200 mg/kg) 30 min after induction of FIP. NETosis was assessed histologically and by quantification for circulating free DNA (cf-DNA) in serum. Autophagy, histone citrullination, endoplasmic reticulum (ER) stress, NF?B activation and apoptosis were investigated in peritoneal PMNs.

Results

Sepsis produced significant NETs in the lungs of VitC deficient Gulo-/- mice and increased circulating cf-DNA. This was attenuated in the VitC sufficient Gulo-/- mice and in VitC deficient Gulo-/- mice infused with AscA. Polymorphonuclear neutrophils (PMNs) from VitC deficient Gulo-/- mice demonstrated increased activation of ER stress, autophagy, histone citrullination, and NF?B activation, while apoptosis was inhibited. VitC also significantly attenuated PMA induced NETosis in PMNs from healthy human volunteers.

Conclusions

Our in vitro and in vivo findings identify VitC as a novel regulator of NET formation in sepsis. This study complements the notion that VitC is protective in sepsis settings.

SUBMITTER: Mohammed BM

PROVIDER: S-EPMC3775246 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

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Publications

Vitamin C: a novel regulator of neutrophil extracellular trap formation.

Mohammed Bassem M BM Fisher Bernard J BJ Kraskauskas Donatas D Farkas Daniela D Brophy Donald F DF Fowler Alpha A AA Natarajan Ramesh R

Nutrients 20130809 8

<h4>Introduction</h4>Neutrophil extracellular trap (NET) formation was recently identified as a novel mechanism to kill pathogens. However, excessive NET formation in sepsis can injure host tissues. We have recently shown that parenteral vitamin C (VitC) is protective in sepsis. Whether VitC alters NETosis is unknown.<h4>Methods</h4>We used Gulo-/- mice as they lack the ability to synthesize VitC. Sepsis was induced by intraperitoneal infusion of a fecal stem solution (abdominal peritonitis, FIP ...[more]

PMID: 23939536

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Project description:Neutrophils undergo a unique form of cell death to generate neutrophil extracellular traps (NETs). It is well established that citrullination of histones (e.g., CitH3) facilitates chromatin decondensation during NET formation (NETosis), particularly during calcium-induced NETosis that is independent of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activation. However, the importance of other forms of histone modifications in NETosis has not been established. We considered that acetylation of histones would also facilitate NETosis. To test this hypothesis, we induced NOX-dependent NETosis in human neutrophils with phorbol myristate acetate or lipopolysaccharide (from Escherichia coli 0128), and NOX-independent NETosis with calcium ionophores A23187 or ionomycin (from Streptomycesconglobatus) in the presence or absence of two pan histone deacetylase inhibitors (HDACis), belinostat and panobinostat (within their half maximal inhibitory concentration (IC50) range). The presence of these inhibitors increased histone acetylation (e.g., AcH4) in neutrophils. Histone acetylation was sufficient to cause a significant increase (~20%) in NETosis in resting neutrophils above baseline values. When acetylation was promoted during NOX-dependent or -independent NETosis, the degree of NETosis additively increased (~15⁻30%). Reactive oxygen species (ROS) production is essential for baseline NETosis (mediated either by NOX or mitochondria); however, HDACis did not promote ROS production. The chromatin decondensation step requires promoter melting and transcriptional firing in both types of NETosis; consistent with this point, suppression of transcription prevented the NETosis induced by the acetylation of histones. Collectively, this study establishes that histone acetylation (e.g., AcH4) promotes NETosis at baseline, and when induced by both NOX-dependent or -independent pathway agonists, in human neutrophils. Therefore, we propose that acetylation of histone is a key component of NETosis.

Dataset Information

Vitamin C: a novel regulator of neutrophil extracellular trap formation.

Introduction

Methods

Results

Conclusions

Publications

Vitamin C: a novel regulator of neutrophil extracellular trap formation.

Similar Datasets

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