title: Intracellular glutathione protects human monocyte-derived macrophages from hypochlorite damage.
abstract: OBJECTIVE
  Macrophages must function in an inflammatory environment of high oxidative stress due to the production of various oxidants. Hypochlorous acid (HOCl) is a potent cytotoxic agent generated by neutrophils and macrophages within inflammatory sites. This study determines whether glutathione is the key factors governing macrophage resistance to HOCl.
  
  
  METHODS
  Human monocyte derived macrophages (HMDM) were differentiated from human monocytes prepared from human blood. The HMDM cells were exposed to micromolar concentrations of HOCl and the timing of the cell viability loss was measured. Cellular oxidative damage was measured by loss of glutathione, cellular ATP, tyrosine oxidation, and inactivation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH).
  
  
  RESULTS
  HOCl causes a rapid loss in HMDM cell viability above threshold concentrations. The cell death occurred within 10 min of treatment with the morphological characteristics of necrosis. The HOCl caused the extensive cellular protein oxidation with the loss of tyrosine residue and inactivation of GAPDH, which was accompanied with the loss of cellular ATP. This cellular damage was only observed after the loss of intracellular GSH from the cell. Removal of intracellular GSH with diethyl maleate (DEM) increased the cells' sensitivity to HOCl damage while protecting the intracellular GSH pool with the antioxidant 7,8-dihydroneopterin prevented the HOCl mediated viability loss. Variations in the HOCl LD(50) for inducing cell death were strongly correlated with initial intracellular GSH levels.
  
  
  CONCLUSIONS
  In HMDM cells scavenging of HOCl by intracellular glutathione is sufficient to protect against oxidative loss of key metabolic functions within the cells.
authors.affiliation: Free Radical Biochemistry Laboratory, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Ya-ting Tina
authors.initials: YT
authors.lastname: Yang
authors.forename: Matthew
authors.initials: M
authors.lastname: Whiteman
authors.forename: Steven P
authors.initials: SP
authors.lastname: Gieseg
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003603:Cytotoxins / Q000009:adverse effects*; D005978:Glutathione / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D006997:Hypochlorous Acid / Q000009:adverse effects*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology; D019798:Neopterin / Q000031:analogs & derivatives / Q000494:pharmacology; D018384:Oxidative Stress
chemical_list: D000975:Antioxidants; D003603:Cytotoxins; C000976:7,8-dihydroneopterin; D019798:Neopterin; D006997:Hypochlorous Acid; D000255:Adenosine Triphosphate; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D005978:Glutathione