Sphingosine and Other Amine-Containing Compounds Induce Rapid NOX-Independent NETosis

NETosis is a form of neutrophil death in which DNA, chromatin, and bactericidal proteins of granules are secreted into the extracellular space and form a network in which pathogenic microorganisms die. The induction of NETosis by small molecular substances (sphingosine, fingolimod, stearylamine, stearic acid, ceramide) is studied. Fluorescence microscopy reveals that sphingosine induces NETosis in a primary culture of human neutrophils within 60 min. Compared with the classic NETosis inducer, phorbol 12-myristate 13-acetate, sphingosine-induced NETosis can be classified as “rapid.” Stearylamine and fingolimod are significantly less active. Ceramide and stearic acid do not enhance NETosis compared with the control. It is found that blocking NADPH oxidase with apocynin and DPI and inhibiting protein kinase C with chelerythrine do not affect the formation of traps under the action of sphingosine. Using the method of chemiluminescence, it is revealed that sphingosine and other studied compounds suppress the oxidative burst of neutrophils induced by phorbol 12-myristate 13-acetate and latex. The results obtained allow us to conclude that sphingosine, stearylamine, and fingolimod induce the development of such a type of NETosis, which is not associated with the activation of NADPH oxidase and develops according to a mechanism different from that of NOX-dependent NETosis development.