Molecular mechanisms of regulation of functional activity of mononuclear phagocytes by leptin.

Leptin is a peptide hormone synthesized by adipocytes. The main function of leptin is associated with regulation of the body energetic balance and restriction of excess accumulation of fat. This review considers in detail the involvement of leptin in regulation of fundamental effector functions of mononuclear phagocytes, which express receptors for this hormone. Possible molecular mechanisms of modulation by leptin of phagocytic activity, oxygen-dependent microbicidity, and nitric oxide generation by mononuclear phagocytes are analyzed, as well as the role of leptin in the formation of the produced cytokine pattern. The data presented suggest that the regulation of mononuclear phagocytes by leptin is associated with activation of the JAK/STAT signaling pathway, which leads to stimulation of phagocytosis, production of oxygen and nitrogen reactive species, and also to increase in secretion of pro-inflammatory cytokines.