Hypochlorous Acid-Modified Serum Albumin Causes NETosis in the Whole Blood Ex Vivo and in Isolated Neutrophils

Type 2 diabetes mellitus (T2DM) is accompanied by halogenative stress resulting from the excessive activation of neutrophils and neutrophilic myeloperoxidase (MPO) generating highly reactive hypochlorous acid (HOCl). HOCl in blood plasma modifies serum albumin (Cl-HSA). We studied the formation of neutrophil extracellular traps (NETs) in the whole blood and by isolated neutrophils under the action of Cl-HSA. It was found that Cl-HSA induces neutrophil priming and NETosis. MPO-containing as well as MPO-free NETs were found. These NETs with different composition can be a product of NETosis of one and the same neutrophil. NET formation in neutrophils with vacuolated cytoplasm was detected. In the presence of Cl-HSA, acceleration of NET degradation was observed. Accelerated NET degradation and neutrophil priming can be the factors contributing to the development of complications in T2DM.