Submitted to: Cellular Signaling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2003
Publication Date: 7/20/2003
Citation: HE, H., KOGUT, M.H. CPG-ODN-INDUCED NITRIC OXIDE PRODUCTION IS MEDIATED THROUGH CLATHRIN-DEPENDENT ENDOCYTOSIS, ENDOSOMAL MATURATION, AND ACTIVATION OF PKC, MEK1/2 AND P38 MAPK, AND NF-KB PATHWAYS IN AVIAN MACROPHAGE CELLS (HD11). CELLULAR SIGNALLING. 2003. V. 15. P. 911-917. Interpretive Summary: DNA is a genetic blueprint of life and occurs in all cells. DNA found in bacteria contains a unique element, called CpG-DNA. Macrophage cells are one type of the white blood cells found in Chickens. The macrophage cells can produce nitric oxide, a chemical that can kill bacteria. The nitric oxide is a very important bacteria-killing chemical that protects chickens from infection by pathogenic bacteria such as Salmonella. We have performed experiments to see if and how macrophage cells produce bacteria-killing nitric oxide when they are exposed to the CpG-DNA. We found that the chicken macrophage can produce nitric oxide after contact with CpG-DNA. We also found that there are very complexed chemical processes taking place in order for the macrophage cells to produce the nitric oxide. This information is important to the pharmaceutical and poultry industries in the United States because it shows us that we can possibly use synthetic CpG-DNA to stimulate chicken macrophage cells to produce nitric oxide and to protect chickens from bacterial infection.
Technical Abstract: We have characterized the nitric oxide (NO) induction by CpG oligodeoxydinucleotide (CpG-ODN) and lipopolysaccharide (LPS) in an avian macrophage cell line (HD11) and evaluated roles of signal transduction pathways by using selective inhibitors. Our results indicate while CpG-ODN and LPS both stimulate inducible NO synthase (iNOS) to produce NO through common signaling pathways involving activation of protein kinase C (PKC), mitogen-activated protein kinases (p38 MAPK and MEK1/2) and transcription factor NF-¿B; CpG-ODN inducing NO production distinctively requires a clathrin-dependent endocytosis and subsequent endosomal maturation. Inhibitors of clathrin-dependent endocytosis such as monodansylcadaverine and hyperosmolar sucrose completely abolished CpG-ODN stimulated NO production by HD11 cells, but has no or less effect on LPS induced NO production. The endosomal maturation is also critical for induction of NO by CpG-ODN, but not by LPS. Our findings are the first to demonstrate cellular signaling pathways that mediate CpG-ODN immunostimulatory activity in cells from non-mammalian species.