The signal transduction pathway involved in the migration induced by a monocyte chemotactic cytokine.
Recombinant monocyte-chemotactic and activating factor (rMCAF; alternative acronyms MCP-1, TDCF, human JE) induced migration of human monocytes across polycarbonate or nitrocellulose filters. Maximal induction of migration was observed at a concentration of 10 ng/ml (10(-9) M). Checkerboard analysis revealed that rMCAF elicited true gradient-dependent chemotactic migration, although a gradient independent chemokinetic effect was observed at low concentrations (1-5 ng/ml). rMCAF caused a rapid (less than 5 s) and transient (approximately 1.5 min) increase of free cytosolic Ca2+ ions, as assessed by the fura-2 probe. No Ca2+ increase was detected in neutrophils or lymphocytes stimulated by rMCAF. Studies conducted in the absence of extracellular Ca2+ or in the presence of Ni2+ (an inhibitor of Ca2+ influx) suggested that the increase of intracellular Ca2+ induced by rMCAF is dependent on the influx of extracellular Ca2+ through plasma membrane channels. Bordetella pertussis toxin inhibited the intracellular Ca2+ elevation and chemotaxis caused by rMCAF. The possible involvement of Ca(2+)-dependent protein kinases in rMCAF signaling pathway(s) was explored using inhibitors. Inhibitors of GMP-dependent kinase and myosin L chain kinase had no effect on rMCAF-induced monocyte migration. In contrast, protein kinase C/cAMP-dependent kinase inhibitors (such as, C-I, H-7, HA-1004, KT5720, and Staurosporine) markedly decreased rMCAF induced chemotaxis suggesting the involvement of a serine/threonine protein kinase, possibly protein kinase C, in rMCAF signaling pathway.
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
S
S
Sozzani
W
W
Luini
M
M
Molino
P
P
Jílek
B
B
Bottazzi
C
C
Cerletti
K
K
Matsushima
A
A
Mantovani
D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000494:pharmacology*; D002633:Chemotaxis; D006801:Humans; D009000:Monocytes / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011494:Protein Kinases / Q000502:physiology; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction
D018932:Chemokine CCL2; D002630:Chemotactic Factors; D011994:Recombinant Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011494:Protein Kinases; D011493:Protein Kinase C; D002118:Calcium