The effect of kisspeptin on the functional activity of peripheral blood monocytes and neutrophils in the context of physiological pregnancy
Hypothalamic hormone kisspeptin is also produced by placental syncytiotrophoblast. Blood leukocytes express a specific membrane receptor of kisspeptin (KISS-1R). Since kisspeptin-54 enters the bloodstream during pregnancy, the hormone has a systemic effect on the leukocytes only in this period. Earlier we demonstrated that kisspeptin-54 enhances the generation of regulatory T (Treg) cells and suppresses the IL-17-producing T helper (Th17) cells. NK cells specialize into a regulatory subtype with reduced cytotoxic activity against fetal cells under the hormone influence. Kisspeptin-54 also regulates the maturation of thymic dendritic cells (DC). However, kisspeptin-54 effect on leukocytes functional activity has not been studied. Although it is known that these cells play an important role in ensuring fetus survival. The aim of the study was investigation of kisspeptin-54 effect in concentrations comparable to its level during physiological pregnancy on neutrophils and monocytes functional activity. Cells were isolated from peripheral blood of healthy non-pregnant women and cultured with kisspeptin-54 for 1 h. The monocytes and neutrophils phagocytic activity was determined by reducing bacterial bioluminescence. The production of reactive oxygen species (ROS) was evaluated in a luminol-dependent chemiluminescence test. The activity of myeloperoxidase (MPO) and indolamine-2,3-dioxygenase (IDO) was determined spectrophotometrically. It was revealed that kisspeptin-54 inhibits phagocytosis, MPO and ROS of neutrophils. On the contrary, the hormone activates phagocytosis, MPO activity, ROS production and IDO activity of monocytes. Thus, received data demonstrate that kisspeptin-54 is an important reproductive hormone that regulates leukocytes functional activity. The action of kisspeptin-54 depends on the type of cells expressing KISS-1 R.