Abstract
Extracellular nicotinamide adenine dinucleotide (NAD) cleaving activity of a particular cell type determines the rate of the degradation of extracellular NAD with formation of metabolites in the vicinity of the plasma membrane, which has important physiological consequences. It is yet to be elucidated whether intact human neutrophils have any extracellular NAD cleaving activity. In this study, with a simple fluorometric assay utilizing 1,N6-ethenoadenine dinucleotide (etheno-NAD) as the substrate, we have shown that intact peripheral human neutrophils have scant extracellular etheno-NAD cleaving activity, which is much less than that of mouse bone marrow neutrophils, mouse peripheral neutrophils, human monocytes and lymphocytes. With high performance liquid chromatography (HPLC), we have identified that ADP-ribose (ADPR) is the major extracellular metabolite of NAD degradation by intact human neutrophils. The scant extracellular etheno-NAD cleaving activity is decreased further by N-formyl-methionine-leucine-phenylalanine (fMLP), a chemoattractant for neutrophils. The fMLP-mediated decrease in the extracellular etheno-NAD cleaving activity is reversed by WRW4, a potent FPRL1 antagonist. These findings show that a much less extracellular etheno-NAD cleaving activity of intact human neutrophils compared to other immune cell types is down-regulated by fMLP via a low affinity fMLP receptor FPRL1.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: The Korean journal of physiology & pharmacology : official journal of the Korean Physiological Society and the Korean Society of Pharmacology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.