Neutrophil extracellular traps activates focal adhesion kinase by upregulating MMP9 expression to promote proliferation and migration of mouse colorectal cancer cells / 细胞与分子免疫学杂志

Objective To investigate how the neutrophil extracellular traps (NETs) affect the proliferation and migration of mouse MC38 colorectal cancer cells and its mechanism. Methods Spleen neutrophils were extracted in mouse, followed by collection of NETs after ionomycin stimulation in vitro. The proliferation of MC38 cell was detected by CCK-8 assay, and migration ability were detected by TranswellTM and cell scratch assay, after co-incubation with MC38 cells. The mRNA expression of cellular matrix metalloproteinase 2 (MMP2) and MMP9 were detected by real-time fluorescence quantitative PCR, and the expression of MMP2, MMP9 and focal adhesion kinase (FAK), phosphorylated FAK protein were detected by Western blot. After silencing MMP9 using small interfering RNA (siRNA), the effect of NETs on the proliferation and migration ability of MC38 cells and the altered expression of related molecules were examined by previous approach. Results NETs promoted the proliferation and migration of MC38 cells and up-regulated the MMP9 expression and FAK phosphorylation. Silencing MMP9 inhibited the promotion of MC38 proliferation and migration by NETs and suppressed FAK phosphorylation. Conclusion NETs up-regulates MMP9 expression in MC38 cells, activates FAK signaling pathway and promotes tumor cell proliferation and migration.

Increased autophagy of peripheral blood neutrophils and neutrophils extracellular traps formation in systemic lupus erythematosus / 细胞与分子免疫学杂志

Objective To explore the role of autophagy, apoptosis of neutrophils and neutrophils extracellular traps (NET) formation in systemic lupus erythematosus (SLE). Methods Thirty-six patients with SLE were recruited as research subjects, and 32 healthy controls matched accordingly were enrolled as control subjects. The expression levels of microtubule associated protein 1 light chain 3B (LC3B), autophagy-related gene5(ATG5), P62, B-cell lymphoma 2(Bcl2), Bcl2-related X protein (BAX) in neutrophils were detected by Western blot analysis. Flow cytometry was employed to analyze the expression of LC3B on neutrophils. The expression level of myeloperoxidase(MPO) in plasma was estimated by ELISA. Furthermore, neutrophils were cultured in vitro and stimulated by 100 nmol/L rapamycin and 10 μg/mL lipopolysaccharide (LPS) for 6 hours, respectively. And then, the expression levels of LC3B, ATG5, P62, Bcl2 and BAX in neutrophils were detected by Western blot analysis. The level of MPO in culture supernatant was detected by ELISA. The change of fluorescence intensity of NET in culture supernatant was assayed by SytoxTM Green staining combined with fluorescence spectrophotometry. Results Compared with healthy controls, the levels of autophagy and apoptosis of neutrophils and NET formation in SLE patients were increased. The level of apoptosis and NET formation was positively associated with neutrophil autophagy. The level of autophagy showed an increase but had no effect on apoptosis and NET formation for neutrophil stimulated by rapamycin. The levels of autophagy and NET formation also increased with no significant effect on apoptosis for neutrophil induced by LPS. Conclusion The autophagy, apoptosis and NET formation of neutrophils increase in SLE patients. The activation of autophagy and NET in neutrophils possibly result from the inflammatory internal environment in SLE patients.

PFKL, a novel regulatory node for NOX2-dependent oxidative burst and NETosis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Neutrophils are predominant leukocytes in the circulation, which are essential for killing invading pathogens via the activation of effector responses and the production of reactive oxygen species (ROS), also named as "oxidative burst." When infected, activated neutrophils fight bacteria, fungi, and viruses through oxidative burst, phagocytosis, degranulation, and the production of neutrophil extracellular traps (NETs) in a neutrophil death process named as "NETosis" (Mutua and Gershwin, 2021). NETs, consisting of DNA fibers decorated with modified histones and numerous antimicrobial proteins from cytoplasmic granules and the nucleus, can either be beneficial or detrimental (Mutua and Gershwin, 2021). Several pathways can lead to this death process. In response to various stimuli, NETosis traps and clears pathogens, facilitating phagocytosis by other neutrophils and phagocytes. However, excessive NETosis often results in disease due to increasing the pro-inflammatory response and perpetuating the inflammatory condition (Hellebrekers et al., 2018; Hidalgo et al., 2019; Klopf et al., 2021). Accordingly, inhibiting aberrant NETosis may alleviate the severity of various autoimmune and inflammatory diseases.

Could neutrophil extracellular traps be the new prognostic markers of cancer?

ABSTRACT Neutrophil extracellular traps (NETs) were described more than one decade ago, but recently, the interest in these structures has increased due to their involvement in cancer progression, cancer-related thrombosis, and development of metastasis. This protumoral role of NETs strengthens their potential as new prognostic markers of cancer.