Down-modulation of L-selectin by lipopolysaccharide is not required for lipopolysaccharide-induced expression of CD14 in mouse bone marrow granulocytes.
We established in previous studies that a constitutive lipopolysaccharide (LPS) receptor of low affinity is present on mouse bone marrow granulocytes (BMG). This yet-unidentified receptor is involved in the LPS-induced expression of a second LPS receptor, CD14. Because it has been claimed that L-selectin (CD62L) is a low-affinity LPS receptor in mature granulocytes (polymorphonuclear leukocytes), it may be asked whether this molecule could be the constitutive LPS receptor in BMG. We show in this study that L-selectin is constitutively present on BMG and is down-regulated after exposure of the cells to LPS. A phorbol ester induced a down-regulation of CD62L and blocked the LPS-induced expression of CD14. However, a metalloproteinase inhibitor (BB-3103) blocked the former but not the latter effect of PMA. We also observed an absence of cross-reactivity between LPS and a CD62L ligand (fucoidan) in binding studies with radiolabeled derivatives of the two agents. Furthermore, BMG from L-selectin-deficient mice expressed normal levels of CD14 in response to LPS. Taken together, these results demonstrate that in BMG, L-selectin is not the constitutive LPS receptor required for the LPS-induced expression of CD14.
Pédron
T
T
Molecular Immunophysiology Unit, URA-1961 of the National Center for Scientific Research, Pasteur Institute, Paris, France.
Girard
R
R
Chaby
R
R
D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006098:Granulocytes / Q000187:drug effects / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D019041:L-Selectin / Q000378:metabolism*; D008024:Ligands; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism* / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007211:Indoles; D008024:Ligands; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008301:Maleimides; D019041:L-Selectin; D011493:Protein Kinase C; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate