[Increased autophagy of peripheral blood neutrophils and neutrophils extracellular traps formation in systemic lupus erythematosus].

Abstract

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 Sytox^TM 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.