Receptors and transduction pathways for monocyte chemotactic protein-2 and monocyte chemotactic protein-3. Similarities and differences with MCP-1.
MCP-2 and MCP-3 are recently identified members of the Cys-Cys chemokine family with high sequence similarity with MCP-1 (62% and 71%, respectively). The present study was aimed at defining receptor usage and signal transduction pathways of MCP-2 and MCP-3 in human monocytes in comparison with MCP-1. MCP-2 and MCP-3 induced migration of monocytes with a typical bell-shaped curve and maximal response at 10 and 50 ng/ml, respectively. The maximal response elicited by MCP-2 and MCP-3 was lower (approximately 60%) than that of MCP-1. Pertussis toxin (PTox) inhibited the chemotactic activity of MCP-3 and MCP-1 (IC50 = 6.2 and 4.4 ng/ml, respectively), whereas cholera toxin (CTox) had little effect on these two chemokines (IC50 > 1000 ng/ml). In contrast, MCP-2-induced chemotaxis was blocked by CTox (IC50 = 75 ng/ml) and relatively unaffected by PTox. MCP-3 and MCP-1 induced a rapid increase in intracellular Ca2+ concentration, whereas MCP-2, in the range of concentrations active on chemotaxis, did not. MCP-1-, MCP-2-, and MCP-3-induced chemotactic responses were blocked by C-I, a serine/threonine kinase inhibitor, and by genistein, a tyrosine kinase inhibitor, with the MCP-2 response being more sensitive than those induced by MCP-1 and MCP-3. MCP-1 and MCP-3 rapidly induced arachidonic acid release whereas MCP-2 was ineffective. MCP-1 and MCP-3 cross-desensitized with each other in terms of Ca2+ transients and displaced with a comparable efficiency labeled MCP-1 from human monocytes. On the other hand, MCP-2 did not cross-desensitize with MCP-1 and MCP-3 and only partially (20%) displaced labeled MCP-1. Thus, in spite of high sequence similarity, MCP-2 differed considerably from MCP-1 and MCP-3 in terms of sensitivity to CTox and PTox, arachidonate and calcium mobilization, and capacity to compete for labeled MCP-1.
Sozzani
S
S
Institute of Pharmacological Research Mario Negri, Milan, Italy.
Zhou
D
D
Locati
M
M
Rieppi
M
M
Proost
P
P
Magazin
M
M
Vita
N
N
van Damme
J
J
Mantovani
A
A
D016718:Arachidonic Acid / Q000378:metabolism; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D018932:Chemokine CCL2; D054410:Chemokine CCL7; D054412:Chemokine CCL8; D002630:Chemotactic Factors / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte; D002772:Cholera Toxin / Q000494:pharmacology; D016207:Cytokines; D006801:Humans; D066298:In Vitro Techniques; D018945:Monocyte Chemoattractant Proteins; D009000:Monocytes / Q000502:physiology*; D037342:Pertussis Toxin; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000378:metabolism*; D015290:Second Messenger Systems; D015398:Signal Transduction; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
C515450:CCL7 protein, human; C515453:CCL8 protein, human; D018932:Chemokine CCL2; D054410:Chemokine CCL7; D054412:Chemokine CCL8; D002630:Chemotactic Factors; D016207:Cytokines; D018945:Monocyte Chemoattractant Proteins; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D010566:Virulence Factors, Bordetella; D016718:Arachidonic Acid; D002772:Cholera Toxin; D037342:Pertussis Toxin; D002118:Calcium