Lipopolysaccharide and interferon-gamma-induced nitric oxide production and protein oxidation in mouse peritoneal macrophages are affected by glutathione peroxidase-1 gene knockout
Yx. Fu et al., Lipopolysaccharide and interferon-gamma-induced nitric oxide production and protein oxidation in mouse peritoneal macrophages are affected by glutathione peroxidase-1 gene knockout, FREE RAD B, 31(4), 2001, pp. 450-459
This study investigated the role of glutathione peroxidase-1 (GPX1) in prot
ein oxidation in peritoneal macrophages. Macrophages isolated from both wil
d-type (WT) and GPX1 knockout (KO) mice were activated by lipopolysaccharid
e (LPS, 1 mug/ml) and interferon-gamma (IFN, 10 U/ml for 24 or 48 h in the
presence or absence of 1 muM diquat (DQ), 250 muM aminoguanidine (AG, an in
hibitor of inducible nitric oxide synthase), and (or) 100 muM diethyldithio
carbamate (DETC, an inhibitor of Cu,Zn-SOD). In the KO macrophages, there w
as no protein band detected by Western blot with anti-GPX1 antibody and 98%
, reduction in total GPX activity compared with WT cells. Nitric oxide (NO)
synthesis was greatly enhanced after 24 h by GPX1 knockout and DQ, but inh
ibited by AG or DETC. Protein carbonyl formation in total cell extract was
clearly associated with NO synthesis as higher levels of protein carbonyl w
ere detected in activated KO than WT macrophages, and DQ enhanced slightly
while AG or DETC virtually blocked its formation. A similarly marginal effe
ct of GPX1 KO was observed on protein nitration. The LPS/IFN/DQ-induced DNA
fragmentation was blocked by AG, but not by DETC. Cell viability at 48 h w
as decreased by the LPS/IFN activation and further reduced by the addition
of DQ, but restored by AG. In conclusion, GPX1 affects the NO production in
activated peritoneal macrophages and protects these cells against NO-assoc
iated protein oxidation. (C) 2001 Elsevier Science Inc.