pbef 1

Pre-B cell colony enhancing factor (PBEF) was originally identified as a cytokine that potentiated the clonal expansion and differentiation of pre-B cells, but it is also acknowledged to be the ubiquitous intracellular enzyme nicotinamide phosphoribosyltranferase (NAMPT) and the adipokine “visfatin”. PBEF is constitutively expressed in the fetal membranes where its greatest expression is in the amnion. It has intracellular and extracellular forms. Most of the intracellular functions of PBEF are due to its role as a Nampt which can induce angiogenesis through upregulation of VEGF and VEGFR and secretion of MCP-1. Extracellular PBEF has been shown to increase inflammatory cytokines, such as TNF-α, IL-1β, IL-16, and TGF-β1. PBEF also increases the production of IL-6, TNF-α, and IL-1β in CD14+ monocyctes, macrophages, and dendritic cells, enhances the effectiveness of T cells.

Nicotinamide phosphoribosyltransferase (NAMPT), also known as pre-B-cell colony-enhancing factor 1 (PBEF1) or visfatin, is an enzyme belonging to the family of glycosyltransferases, to be specific, the pentosyltransferases. This enzyme participates in nicotinate and nicotinamide metabolism. This enzyme catalyzes the condensation of nicotinamide with 5- phosphoribosyl-1- pyrophosphate to yield nicotinamide mononucleotide, one step in the biosynthesis of nicotinamide adenine dinucleotide. NAMPT is also considered as an essential enzyme mediating granulocyte colony-stimulating factor (G-CSF)-triggered granulopoiesis in healthy individuals and individuals with severe congenital neutropenia. Intracellular NAMPT and NAD+amounts in myeloid cells, as well as plasma NAMPT and NAD+levels, were increased by G-CSF treatment of both healthy volunteers and individuals with congenital neutropenia.