Trypanosoma evansi triggered neutrophil extracellular traps formation dependent on myeloperoxidase, neutrophil elastase, and extracellular signal-regulated kinase 1/2 signaling pathways

2021 ◽  
pp. 109502
Author(s):  
Ran Wei ◽  
Xin Li ◽  
Xiaocen Wang ◽  
Yuru Wang ◽  
Xu Zhang ◽  
...  
2010 ◽  
Vol 191 (3) ◽  
pp. 677-691 ◽  
Author(s):  
Venizelos Papayannopoulos ◽  
Kathleen D. Metzler ◽  
Abdul Hakkim ◽  
Arturo Zychlinsky

Neutrophils release decondensed chromatin termed neutrophil extracellular traps (NETs) to trap and kill pathogens extracellularly. Reactive oxygen species are required to initiate NET formation but the downstream molecular mechanism is unknown. We show that upon activation, neutrophil elastase (NE) escapes from azurophilic granules and translocates to the nucleus, where it partially degrades specific histones, promoting chromatin decondensation. Subsequently, myeloperoxidase synergizes with NE in driving chromatin decondensation independent of its enzymatic activity. Accordingly, NE knockout mice do not form NETs in a pulmonary model of Klebsiella pneumoniae infection, which suggests that this defect may contribute to the immune deficiency of these mice. This mechanism provides for a novel function for serine proteases and highly charged granular proteins in the regulation of chromatin density, and reveals that the oxidative burst induces a selective release of granular proteins into the cytoplasm through an unknown mechanism.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 317
Author(s):  
HanGoo Kang ◽  
Jinwon Seo ◽  
Eun-Jeong Yang ◽  
In-Hong Choi

Silver nanoparticles (AgNPs) are widely used in various fields because of their antimicrobial properties. However, many studies have reported that AgNPs can be harmful to both microorganisms and humans. Reactive oxygen species (ROS) are a key factor of cytotoxicity of AgNPs in mammalian cells and an important factor in the immune reaction of neutrophils. The immune reactions of neutrophils include the expulsion of webs of DNA surrounded by histones and granular proteins. These webs of DNA are termed neutrophil extracellular traps (NETs). NETs allow neutrophils to catch and destroy pathogens in extracellular spaces. In this study, we investigated how AgNPs stimulate neutrophils, specifically focusing on NETs. Freshly isolated human neutrophils were treated with 5 or 100 nm AgNPs. The 5 nm AgNPs induced NET formation, but the 100 nm AgNPs did not. Subsequently, we investigated the mechanism of AgNP-induced NETs using known inhibitors related to NET formation. AgNP-induced NETs were dependent on ROS, peptidyl arginine deiminase, and neutrophil elastase. The result in this study indicates that treatment of 5 nm AgNPs induce NET formation through histone citrullination by peptidyl arginine deiminase and histone cleavage by neutrophil elastase.


2008 ◽  
Vol 80 (12) ◽  
pp. 2735-2750
Author(s):  
Ju-Pi Li ◽  
Chun-Yu Wang ◽  
Yen-An Tang ◽  
Yun-Wei Lin ◽  
Jia-Ling Yang

Arsenic and lead can induce genetic injuries and epigenetic signaling pathways in cultured mammalian cells. To test whether signaling pathways affect the extent of genetic injuries, we explored the impacts of extracellular signal-regulated kinase 1 and 2 (ERK) on nucleotide excision repair (NER), cytotoxicity, and genotoxicity following sodium arsenite [As(III)] and lead acetate [Pb(II)]. Sustained ERK activation was observed in human cells exposed to As(III) and Pb(II). As(III) inhibited the cellular NER synthesis capability; conversely, Pb(II) stimulated it. ERK activation contributed to the As(III)-induced NER inhibition and micronucleus formation. In contrast, this signal was required for inducing cellular NER activity and preventing mutagenesis following Pb(II). ERK activation by Pb(II) was dependent on protein kinase C (PKCα) that also exhibited anti-mutagenicity. Enforced expression of ERK signaling markedly elevated the cellular NER activity, which was suppressed by As(III). Nonetheless, ERK activation could counteract the cytotoxicity caused by these two metals. Together, the results indicate that pro-survival ERK signaling exhibits dual and opposing impacts on NER process following As(III) and Pb(II) exposures. The findings also suggest that ERK is an important epigenetic signaling in the determination of metal genotoxicity.


2019 ◽  
Vol 20 (12) ◽  
pp. 2899 ◽  
Author(s):  
Dong Kyung Sung ◽  
Se In Sung ◽  
So Yoon Ahn ◽  
Yun Sil Chang ◽  
Won Soon Park

We investigated the role of protease-activated receptor (PAR)-mediated signaling pathways in the biogenesis of human umbilical cord blood-derived mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) and the enrichment of their cargo content after thrombin preconditioning. Immunoblot analyses showed that MSCs expressed two PAR subtypes: PAR-1 and PAR-3. Thrombin preconditioning significantly accelerated MSC-derived EV biogenesis more than five-fold and enriched their cargo contents by more than two-fold via activation of Rab5, early endosomal antigen (EEA)-1, and the extracellular signal regulated kinase (ERK)1/2 and AKT signaling pathways. Blockage of PAR-1 with the PAR-1-specific antagonist, SCH79797, significantly suppressed the activation of Rab5, EEA-1, and the ERK1/2 and AKT pathways and subsequently increased EV production and enriched EV cargo contents. Combined blockage of PAR-1 and PAR-3 further and significantly inhibited the activation of Rab5, EEA-1, and the ERK1/2 and AKT pathways, accelerated EV production, and enriched EV cargo contents. In summary, thrombin preconditioning boosted the biogenesis of MSC-derived EVs and enriched their cargo contents largely via PAR-1-mediated pathways and partly via PAR-1-independent, PAR-3-mediated activation of Rab5, EEA-1, and the ERK1/2 and AKT signaling pathways.


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