Methotrexate inhibits superoxide production and chemotaxis in neutrophils activated by granulocyte colony-stimulating factor.
Treatment of circulating human neutrophils with recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 30 min augmented superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in a dose dependent manner. When neutrophils were treated with 1 microM of methotrexate (MTX) for 60 min after incubation with rhG-CSF (10 ng/ml), the effects of rhG-CSF on superoxide generation and chemotaxis were inhibited by approximately 49 and 29%, respectively. Although inhibitory effects of MTX were also seen in neutrophils not pretreated with rhG-CSF, the degree of inhibition was much less. The addition of either hypoxanthine or guanosine at a concentration of 100 microM to the culture medium significantly attenuated the effects of MTX. However, in neutrophils obtained from a patient with Lesch-Nyhan syndrome, which lacked hypoxanthine-guanine phosphoribosyl transferase activity neither hypoxanthine nor guanosine had any rescue effect. These results suggest that MTX inhibits superoxide generation and chemotaxis in rhG-CSF-activated neutrophils, at least in part, by disturbing purine nucleotide biosynthesis.
Okuda
A
A
Department of Pediatrics, Faculty of Medicine, Kyoto University, Japan.
Kubota
M
M
Sawada
M
M
Koishi
S
S
Kataoka
A
A
Bessho
R
R
Usami
I
I
Lin
Y W
YW
Adachi
S
S
Furusho
K
K
D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D005493:Folic Acid Antagonists / Q000494:pharmacology*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006151:Guanosine / Q000494:pharmacology; D006801:Humans; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000494:pharmacology; D007926:Lesch-Nyhan Syndrome; D002955:Leucovorin / Q000494:pharmacology; D008727:Methotrexate / Q000494:pharmacology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects*; D011994:Recombinant Proteins; D016897:Respiratory Burst / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism*
D005493:Folic Acid Antagonists; D007042:Hypoxanthines; D011994:Recombinant Proteins; D013481:Superoxides; D006151:Guanosine; D016179:Granulocyte Colony-Stimulating Factor; D019271:Hypoxanthine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002955:Leucovorin; D008727:Methotrexate