The c-kit ligand stem cell factor and anti-IgE promote expression of monocyte chemoattractant protein-1 in human lung mast cells.
Recent data suggest that mast cells (MC) are involved in the regulation of leukocyte accumulation in inflammatory reactions. In this study, expression of leukocyte-chemotactic peptides (chemokines) in purified human lung MC (n = 16) and a human mast cell line, HMC-1, was analyzed. Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) showed baseline expression of monocyte chemoattractant protein (MCP)-1 mRNA in unstimulated MC. Exposure of MC to recombinant stem cell factor (rhSCF, 100 ng/mL) or anti-IgE (10 microgram/mL) was followed by a substantial increase in expression of MCP-1 mRNA. Neither unstimulated nor stem cell factor (SCF )-stimulated lung MC expressed transcripts for interleukin-8 (IL-8), macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, or RANTES by Northern blotting. The mast cell line HMC-1, which contains a mutated and intrinsically activated SCF-receptor, was found to express high levels of MCP-1 mRNA in a constitutive manner. Exposure of HMC-1 cells to rhSCF resulted in upregulation of MCP-1 mRNA expression, and de novo expression of MIP-1beta mRNA. The SCF-induced upregulation of MCP-1 mRNA in lung MC and HMC-1 was accompanied by an increase in immunologically detectable MCP-1 in cell supernatants (sup) (lung MC [<98%], control medium, 1 hour: 159 +/- 27 v SCF, 100 ng/mL, 1 hour: 398 +/- 46 pg/mL/10(6) cells; HMC-1: control, 1 hour: 894 +/- 116 v SCF, 1 hour: 1,536 +/- 265 pg/mL/10(6)). IgE-dependent activation was also followed by MCP-1 release from MC. MC-sup and HMC-1-sup induced chemotaxis in blood monocytes (Mo) (control: 100% +/- 12% v 2-hour-MC-sup: 463% +/- 38% v HMC-1-sup: 532% +/- 12%), and a monoclonal antibody (MoAb) to MCP-1 (but not MoAb to IL-8) inhibited Mo-chemotaxis induced by MC-sup or HMC-1-sup (39% to 55% inhibition, P < .05). In summary, our study identifies MCP-1 as the predominant CC-chemokine produced and released in human lung MC. MCP-1 may be a crucial mediator in inflammatory reactions associated with MC activation and accumulation of MCP-1-responsive leukocytes.
Baghestanian
M
M
Department of Internal Medicine I, the Division of Hematology and Hemostaseology, University of Vienna, Austria.
Hofbauer
R
R
Kiener
H P
HP
Bankl
H C
HC
Wimazal
F
F
Willheim
M
M
Scheiner
O
O
Füreder
W
W
Müller
M R
MR
Bevec
D
D
Lechner
K
K
Valent
P
P
D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology*; D018932:Chemokine CCL2 / Q000096:biosynthesis*; D002633:Chemotaxis / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008407:Mast Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology*
D000888:Antibodies, Anti-Idiotypic; D018932:Chemokine CCL2; D012333:RNA, Messenger; D019089:Stem Cell Factor; C026408:anti-IgE antibodies