Stimulus-dependent chromatin dynamics, citrullination, calcium signalling and ROS production during NET formation

Publication date: Available online 25 August 2018Source: Biochimica et Biophysica Acta (BBA) - Molecular Cell ResearchAuthor(s): Cynthia M. de Bont, Werner J.H. Koopman, Wilbert C. Boelens, Ger J.M. PruijnAbstractNeutrophils can release their chromatin to form neutrophil extracellular traps (NETs), a process known as NETosis. Although NET formation can be induced by various stimuli, recent evidence suggests that these stimuli do so via different mechanisms. Here, we have analysed NET formation induced by lipopolysaccharide (LPS), phorbol 12‑myristate 13‑acetate (PMA) and the calcium (Ca2+) ionophore A23187. Our results show distinct peroxidase and neutrophil elastase activities in both culture supernatant and NETs. Especially stimulation with A23187 led to pronounced peroxidase and elastase release and yielded high peroxidase activity on the resulting NETs. In contrast to LPS and PMA, A23187 did not induce morphological changes of the nuclei. Histone H3 citrullination was more extensively observed upon induction by A23187 and particularly in LPS- and PMA-induced NETs the detection of citrullinated H3 was dependent on the inhibition of neutrophil proteases, which suggests that NET-associated citrullinated histones are readily cleaved by these proteases. With live cell imaging techniques, differences in the rate of plasma membrane permeabilization were observed, not only for the different inducers, but also among individual neutrophils. LPS and PMA, but not A23187, induced ...
Source: Biochimica et Biophysica Acta (BBA) Molecular Cell Research - Category: Molecular Biology Source Type: research