Inhibition of Mg2+-dependent Adhesion of Polymorphonuclear Leukocytes by Serum Hemopexin: Differences in Divalent-Cation Dependency of Cell Adhesion in the Presence and Absence of Serum

Cell Structure and Function

Hideo Namiki¹  Ikuko Machida¹  Tomoko Doi¹  Kingo Suzuki¹  Tomoko Hijikata¹  Nobuharu Kobayashi¹ 

[1] Department of Biology, School of Education, Waseda University

关键词: Hemopexin;    polymorphonuclear leukocyte;    adhesion;    serum;    divalent cation;   

DOI  :  10.1247/csf.28.243

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(64)Cited-By(6)Circulating and nonadherent polymorphonuclear leukocytes (PMNs) become activated to attain adhesive state in an integrin-dependent manner by various stimuli, and perform a variety of microbicidal functions such as phagocytosis and superoxide production. We found that, in the absence of serum, a physiological concentration of hemopexin has a strong inhibitory action on Mg2+-dependent adhesion of PMA-activated PMNs to fibrinogen- and serum-coated surfaces. Under these conditions, Ca2+ had no effect on Mg2+-dependent adhesion or the adhesion-inhibitory activity of hemopexin. In contrast, PMNs suspended in serum containing sufficient amounts of hemopexin to inhibit adhesion showed marked adherence, which was inhibited by EGTA. Next, we prepared a small-molecule fraction of serum by ultrafiltration followed by boiling. PMA-activated PMNs was found to adhere in the presence of both hemopexin and the small-molecule fraction, and the adhesion was enhanced by exogenous Ca2+. EGTA abolished the effect of the small molecule fraction. The data suggest that serum contains adhesion-promoting factor(s) which allows PMNs to adhere despite the presence of hemopexin and that Ca2+ is required for adhesion-promoting activity. Further study of hemopexin may provide clues for new therapeutic strategies aimed at interfering with PMN adhesion to control inflammation and tissue injury.

【 授权许可】

Unknown