Modulation of transmembrane signalling in HL-60 granulocytes by tumour necrosis factor-alpha.
Differentiated HL-60 granulocytes were used to study the mechanism by which tumour necrosis factor-alpha (TNF) enhances responses to N-formyl-methionyl-leucylphenylalanine (FMLP). Cultivation of differentiated HL-60 cells with 100 units of TNF/ml for 24 h resulted in a 3-fold increase in superoxide release and 4-fold increase in prostaglandin E2 production on stimulation with 1 microM-FMLP. On the other hand, cultivation with TNF failed to increase phorbol diester stimulation of superoxide release. Formyl-peptide-receptor expression determined on isolated membranes from cells cultivated with TNF (TNF-M) was increased by 50% compared with membranes from control cells (NM). Similarly, FMLP binding to intact HL-60 cells was increased by cultivation with TNF. Guanine-nucleotide-binding proteins (G-protein) levels were not different between TNF-M and NM, as determined by pertussis-toxin-catalysed ADP-ribosylation and by immunoblotting with antisera recognizing alpha i2 subunit. Binding of guanosine 5'-[gamma-thio]triphosphate and GTP hydrolysis stimulated by FMLP were enhanced by about 50% in TNF-M. The efficiency of G-protein activation by formyl-peptide receptors did not differ between TNF-M and NM. TNF regulates expression of formyl-peptide receptors independently of G-protein levels. The regulation of receptor expression is one mechanism by which TNF enhances cell responses to formylated peptides.
McLeish
K R
KR
Department of Medicine, University of Louisville Health Sciences Center, KY 40292.
Klein
J B
JB
Schepers
T
T
Sonnenfeld
G
G
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D015232:Dinoprostone / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D015151:Immunoblotting; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D037342:Pertussis Toxin; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000502:physiology; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000378:metabolism
D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D014409:Tumor Necrosis Factor-alpha; D010566:Virulence Factors, Bordetella; D013481:Superoxides; D000246:Adenosine Diphosphate Ribose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D009240:N-Formylmethionine Leucyl-Phenylalanine; D006160:Guanosine Triphosphate; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D015232:Dinoprostone