Signal regulatory protein alpha ligation induces macrophage nitric oxide production through JAK/STAT- and phosphatidylinositol 3-kinase/Rac1/NAPDH oxidase/H2O2-dependent pathways.
Signal regulatory protein alpha (SIRPalpha) is a glycoprotein receptor that recruits and signals via the tyrosine phosphatases SHP-1 and SHP-2. In macrophages SIRPalpha can negatively regulate the phagocytosis of host cells and the production of tumor necrosis factor alpha. Here we provide evidence that SIRPalpha can also stimulate macrophage activities, in particular the production of nitric oxide (NO) and reactive oxygen species. Ligation of SIRPalpha by antibodies or soluble CD47 triggers inducible nitric oxide synthase expression and production of NO. This was not caused by blocking negative-regulatory SIRPalpha-CD47 interactions. SIRPalpha-induced NO production was prevented by inhibition of the tyrosine kinase JAK2. JAK2 was found to associate with SIRPalpha in macrophages, particularly after SIRPalpha ligation, and SIRPalpha stimulation resulted in JAK2 and STAT1 tyrosine phosphorylation. Furthermore, SIRPalpha-induced NO production required the generation of hydrogen peroxide (H(2)O(2)) by a NADPH oxidase (NOX) and the phosphatidylinositol 3-kinase (PI3-K)-dependent activation of Rac1, an intrinsic NOX component. Finally, SIRPalpha ligation promoted SHP-1 and SHP-2 recruitment, which was both JAK2 and PI3-K dependent. These findings demonstrate that SIRPalpha ligation induces macrophage NO production through the cooperative action of JAK/STAT and PI3-K/Rac1/NOX/H(2)O(2) signaling pathways. Therefore, we propose that SIRPalpha is able to function as an activating receptor.
Alblas
Jacqueline
J
Department of Molecular Cell Biology and Immunology, VU Medical Center, MB Amsterdam, The Netherlands.
Honing
Henk
H
de Lavalette
Chantal Renardel
CR
Brown
Marion H
MH
Dijkstra
Christine D
CD
van den Berg
Timo K
TK
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D000943:Antigens, Differentiation / Q000378:metabolism*; D015153:Blotting, Western; D051928:CD47 Antigen; D002867:Chromones / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D053614:Janus Kinase 2; D008264:Macrophages / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008954:Models, Biological; D009025:Morpholines / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species; D011971:Receptors, Immunologic / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016897:Respiratory Burst; D015398:Signal Transduction; D013950:Thymus Gland / Q000378:metabolism; D013997:Time Factors; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
D015703:Antigens, CD; D000943:Antigens, Differentiation; D051928:CD47 Antigen; D002867:Chromones; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009025:Morpholines; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat; D020830:rac1 GTP-Binding Protein