Ziegelstein R C, Corda S, Pili R, Passaniti A, Lefer D, Zweier J L, Fraticelli A, Capogrossi M C
Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Md.
Circulation. 1994 Oct;90(4):1899-907. doi: 10.1161/01.cir.90.4.1899.
Increases in both leukocyte and endothelial cytosolic free [Ca2+] may be involved in intercellular adhesion by regulating the affinity of surface adhesion molecules or by facilitating transendothelial leukocyte migration. The purpose of this study was to examine the effect of initial contact and subsequent adhesion of human neutrophils or monocytes on human aortic endothelial [Ca2+].
Endothelial monolayers were loaded with the fluorescent Ca2+ indicator indo 1 and exposed to isolated human peripheral blood neutrophils or to a cultured human monocyte cell line. A rapid, fourfold to fivefold increase in endothelial cytosolic [Ca2+] occurred within seconds of leukocyte contact. No increase in endothelial [Ca2+] occurred on contact of 18.25-microns inert microspheres, isolated red blood cells, or suspensions of cultured human aortic endothelial cells. In experiments performed on monolayers grown in 1-mm2 capillary flow tubes, the increase in endothelial cytosolic [Ca2+] on initial leukocyte contact was found to be related to the subsequent resistance to leukocyte detachment during exposure to arterial levels of shear stress (13.4 dyne.cm-2). The increase in endothelial cytosolic [Ca2+] during leukocyte contact was not inhibited in Ca(2+)-free buffer but was abolished by prior depletion of an endoplasmic reticulum Ca2+ store by thapsigargin. Pretreatment of neutrophils with R15.7, a specific monoclonal antibody to the adhesion protein CD-18, inhibited the increase in endothelial cytosolic [Ca2+] on neutrophil contact.
Initial contact leading to subsequent adhesion of human leukocytes to human aortic endothelial cells releases an endothelial intracellular Ca2+ store. This may, in part, be mediated by specific adhesion proteins and may in turn regulate the affinity of surface adhesion molecules or facilitate transendothelial migration of leukocytes.
白细胞和内皮细胞胞浆游离钙离子浓度升高可能通过调节表面黏附分子的亲和力或促进白细胞跨内皮迁移参与细胞间黏附。本研究旨在探讨人中性粒细胞或单核细胞的初始接触及随后黏附对人主动脉内皮细胞钙离子浓度的影响。
内皮细胞单层负载荧光钙离子指示剂indo 1，然后与分离的人外周血中性粒细胞或培养的人单核细胞系接触。白细胞接触后数秒内，内皮细胞胞浆钙离子浓度迅速升高4至5倍。18.25微米的惰性微球、分离的红细胞或培养的人主动脉内皮细胞悬液接触时，内皮细胞钙离子浓度无升高。在1平方毫米毛细管流管中生长的单层细胞上进行的实验发现，白细胞初始接触时内皮细胞胞浆钙离子浓度升高与随后在动脉水平剪切应力（13.4达因·厘米-2）作用下白细胞脱离的阻力有关。白细胞接触期间内皮细胞胞浆钙离子浓度升高在无钙缓冲液中未受抑制，但在毒胡萝卜素预先耗尽内质网钙离子储存后被消除。用抗黏附蛋白CD-18的特异性单克隆抗体R15.7预处理中性粒细胞可抑制中性粒细胞接触时内皮细胞胞浆钙离子浓度升高。
人白细胞与主动脉内皮细胞的初始接触导致随后黏附，释放内皮细胞内的钙离子储存。这可能部分由特定黏附蛋白介导，进而可能调节表面黏附分子的亲和力或促进白细胞跨内皮迁移。
