S-nitrosoglutathione enhances neutrophil DNA fragmentation and cell death

• Published in: American journal of physiology. Lung cellular and molecular physiology 1999-03, Vol.276 (3), p.435-L442
• Main Authors: Fortenberry, James D, Owens, Marilyn L, Brown, Lou Ann S
• Format: Article
• Language: English
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.1999.276.3.l435

1  Egleston Pediatric Subspecialists, Egleston Children's Health System, and Divisions of 2  Critical Care and 3  Neonatology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322 Enhancing the clearance of neutrophils by enhancing apoptotic cell death and macrophage recognition may be beneficial in acute lung injury. Exogenous nitric oxide gas depresses neutrophil oxidative functions and accelerates cell death (A. H. Daher, J. D. Fortenberry, M. L. Owens, and L. A. Brown. Am. J. Respir. Cell Mol. Biol. 16: 407-412, 1997). We hypothesized that S -nitrosoglutathione (GSNO), a physiologically relevant nitric oxide donor, could also enhance neutrophil DNA fragmentation. Neutrophils were incubated for 2-24 h in the absence and presence of GSNO (dose range 0.1-5 mM) and evaluated for cell death by a fluorescent viability/cytotoxicity assay. Neutrophil DNA fragmentation was assessed by cell death detection ELISA and by terminal deoxynucleotidyltransferase-mediated fluorescence-labeled dUTP nick end labeling assay. Neutrophil oxidative function was also determined. Incubation with GSNO increased cell death at 2, 4, and 24 h. GSNO incubation for 24 h significantly increased DNA fragmentation in a dose-dependent fashion at 0.5   (median 126% of control value; P  = 0.002) and 5 mM (185% of control value; P  = 0.002) by terminal deoxynucleotidyltransferase-mediated fluorescence-labeled dUTP nick end labeling and at 0.5 mM by ELISA (164% of control value; P  = 0.03). The apoptosis-to-total cell death ratio increased with increasing GSNO concentration ( P  <   0.05). Effects were mitigated by coincubation with superoxide dismutase. Five millimolar GSNO decreased overall superoxide generation and O 2 consumption but not when adjusted for dead neutrophils. GSNO significantly enhances cell death and neutrophil DNA fragmentation in a dose-dependent fashion. nitric oxide; apoptosis; S -nitrosothiol; glutathione