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Nitrosative stress inhibits the aminophospholipid translocase resulting in phosphatidylserine externalization and macrophage engulfment.
Tyurina YY; Basova LV; Konduru NV; Tyurin VA; Potapovich AI; Cai P; Bayir H; Stoyanovsky D; Pitt BR; Shvedova AA; Fadeel B; Kagan VE
J Biol Chem 2007 Mar; 282(11):8498-8509
Macrophage recognition of apoptotic cells depends on externalization of phosphatidylserine (PS), which is normally maintained within the cytosolic leaflet of the plasma membrane by aminophospholipid translocase (APLT). APLT is sensitive to redox modifications of its -SH groups. Because activated macrophages produce reactive oxygen and nitrogen species, we hypothesized that macrophages can directly participate in apoptotic cell clearance by S-nitrosylation/oxidation and inhibition of APLT causing PS externalization. Here we report that exposure of target HL-60 cells to nitrosative stress inhibited APLT, induced PS externalization, and enhanced recognition and elimination of "nitrosatively" modified cells by RAW 264.7 macrophages. Using S-nitroso-L-cysteine-ethyl ester (SNCEE) and S-nitrosoglutathione (GSNO) that cause intracellular and extracellular trans-nitrosylation of proteins, respectively, we found that SNCEE (but not GSNO) caused significant S-nitrosylation/oxidation of thiols in HL-60 cells. SNCEE also strongly inhibited APLT, activated scramblase, and caused PS externalization. However, SNCEE did not induce caspase activation or nuclear condensation/fragmentation suggesting that PS externalization was dissociated from the common apoptotic pathway. Dithiothreitol reversed SNCEE-induced S-nitrosylation, APLT inhibition, and PS externalization. SNCEE but not GSNO stimulated phagocytosis of HL-60 cells. Moreover, phagocytosis of target cells by lipopolysaccharide-stimulated macrophages was significantly suppressed by an NO. scavenger, DAF-2. Thus, macrophage-induced nitrosylation/oxidation plays an important role in cell clearance, and hence in the resolution of inflammation.
Blood cells; Blood disorders; Immune system disorders; Cell alteration; Cell metabolism; Cell function; Cell biology; Amino compounds; Protein chemistry
National Institute of Occupational Safety and Health, Morgantown, West Virginia 26505
Issue of Publication
Journal of Biological Chemistry
University of Pittsburgh at Pittsburgh
Page last reviewed: April 9, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division