Abstract
To further elucidate mechanisms involved in mast cell accumulation at sites of cutaneous inflammation, we have studied the ability of human leukemic mast cells (HMC-1 cells) to express functionally active IL-8 receptors. Expression of mRNA for both types of IL-8 receptors (CXCR1 and CXCR2) was demonstrated by PCR and of both proteins by flow cytometry. Binding and competition studies with 125I-labeled IL-8 and its homologue melanoma growth stimulating activity (125I-labeled MGSA) revealed two specific binding sites for IL-8, K1 = 1.1 x 10(11) M(-1) and K2 = 5 x 10(7) M(-1); and for MGSA, K1 = 2.8 x 10(10) M(-1) and K2 = 5 x 10(7) M(-1). This finding was supported by a dose-dependent rise of cytosolic free calcium concentration ([Ca2+]i) induced by both chemokines and to a lesser extent by the homologue neutrophil-activating peptide-2 (NAP-2). A significant migratory response of human leukemic mast cells (HMC-1) was observed with all three chemokines at a range from 10(-8) M to 10(-9) M. Moreover, the formation of cellular F-actin was induced in a rapid, dose-dependent fashion, with a maximally 1.7-fold increase at 10(-7) M. Using postembedding immunoelectron microscopy, we could show the expression of CXCRI on the cytoplasmatic membrane of isolated human skin mast cells whereas CXCR2 was located in mast cell-specific granules. These findings demonstrate for the first time the functional expression of both types of IL-8 receptors on human mast cells, suggesting a role for their ligands during mast cell activation and recruitment.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / metabolism
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Antigens, CD / biosynthesis*
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Antigens, CD / genetics
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Antigens, CD / physiology
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Antigens, CD / ultrastructure
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Binding, Competitive
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Calcium / metabolism
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Cell Movement / drug effects
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Chemokine CXCL1
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Chemokines, CXC*
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Chemotactic Factors / metabolism
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Chemotactic Factors / pharmacology
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Flow Cytometry
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Growth Substances / metabolism
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Growth Substances / pharmacology
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HL-60 Cells
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Humans
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Intercellular Signaling Peptides and Proteins*
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Interleukin-8 / metabolism*
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Interleukin-8 / pharmacology
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Iodine Radioisotopes
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Mast Cells / metabolism*
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Mast Cells / physiology
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Mast Cells / ultrastructure
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Peptides / pharmacology
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Polymerase Chain Reaction
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Protein Binding
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RNA, Messenger / biosynthesis
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Receptors, Chemokine / biosynthesis*
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Receptors, Chemokine / genetics
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Receptors, Chemokine / physiology
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Receptors, Interleukin / biosynthesis*
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Receptors, Interleukin / genetics
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Receptors, Interleukin / physiology
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Receptors, Interleukin / ultrastructure
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Receptors, Interleukin-8A
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Receptors, Interleukin-8B
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Skin / metabolism
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Skin / ultrastructure
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Tumor Cells, Cultured
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beta-Thromboglobulin
Substances
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Actins
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Antigens, CD
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CXCL1 protein, human
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Chemokine CXCL1
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Chemokines, CXC
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Chemotactic Factors
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Growth Substances
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Intercellular Signaling Peptides and Proteins
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Interleukin-8
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Iodine Radioisotopes
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PPBP protein, human
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Peptides
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RNA, Messenger
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Receptors, Chemokine
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Receptors, Interleukin
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Receptors, Interleukin-8A
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Receptors, Interleukin-8B
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beta-Thromboglobulin
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connective tissue-activating peptide
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Calcium