Fibrinogen and Ceruloplasmin Modulate Neutrophils' Biomechanics and Motility

Neutrophils are the most abundant cells of the innate immune system, migrating from the bloodstream into tissues to the focus of inflammation. They are extremely sensitive to the microenvironment, including the composition of blood plasma. In our previous works, the influence of acute phase proteins such as ceruloplasmin and fibrinogen on the ability of peripheral blood neutrophils to generate reactive oxygen species was shown. In this investigation, we showed the effect of the interaction of neutrophil with both fibrinogen and ceruloplasmin on the dynamics of changes in the rigidity of neutrophil activated by phorbol myristate acetate, which leads to a change in the ability of neutrophil to migrate. It has been demonstrated that the interaction of neutrophils with ceruloplasmin reduces the rate of ameboid movement of neutrophils, and the interaction of neutrophils with fibrinogen increases the rate of ameboid movement of a subpopulation of neutrophils. Also, the results on these proteins' influence on neutrophils' surface flexibility have been obtained. All mentioned characteristics are essential for neutrophils' functioning. The experiments were carried out using confocal microscopy and scanning ion-conductance microscopy. Our results demonstrated that interaction with fibrinogen and ceruloplasmin affects both motility and rigidity of peripheral blood neutrophils.