CELL-FREE POOL OF CD14 MEDIATES ACTIVATION OF TRANSCRIPTION FACTOR NF-KAPPA-B BY LIPOPOLYSACCHARIDE IN HUMAN ENDOTHELIAL-CELLS
CELL-FREE POOL OF CD14 MEDIATES ACTIVATION OF TRANSCRIPTION FACTOR NF-KAPPA-B BY LIPOPOLYSACCHARIDE IN HUMAN ENDOTHELIAL-CELLS
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DOI：
10.1073/pnas.90.21.9887
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发表时间：
1993-11-01
影响因子：
11.1
通讯作者：
HAWIGER, J
中科院分区：
文献类型：
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作者：
READ, MA;CORDLE, SR;HAWIGER, J
脂多糖（LPS）是革兰氏阴性菌的主要外膜成分，是感染性休克和弥散性血管内凝血的最常见病原体。LPS激活CD 14阳性（单核细胞、巨噬细胞、多形核白细胞）和CD 14阴性（B细胞系、内皮细胞）细胞。CD 14是一种存在于成熟骨髓细胞上的55-kDa糖基-磷脂酰肌醇锚定膜蛋白，作为LPS的受体与可溶性（血清衍生的）LPS结合蛋白（LBP）复合。在这份报告中，我们表明，人脐静脉内皮细胞（HUVEC），不表达可测量的CD 14蛋白，成为3000倍更敏感的LPS诱导的激活在血清的存在下，通过激活的转录因子NF-κ B和表达的mRNA编码的组织因子，促凝血分子。HUVEC的这种增强的反应性是由血清中发现的CD 14（可溶性CD 14，sCD 14）的无细胞池特异性介导的。sCD 14在LPS激活HUVEC中的作用是通过以下方式确定的：（i）单克隆抗CD 14抗体的阻断作用，其区分细胞结合的和sCD 14，（ii）sCD 14的免疫耗竭后缺乏血清增强作用，以及（iii）建立重组系统，其中重组sCD 14足以在不存在血清且不需要对于LBP因此，这种LPS激活内皮细胞的机制涉及sCD 14的无细胞池，最有可能是从单核细胞系的CD 14阳性细胞脱落的。
Lipopolysaccharide (LPS), a major envelope component Of GraM-negative bacteria, is the most frequent causative agent of septic shock and disseminated intravascular coagulation. LPS activates both CD14-positive (monocytes, macrophages, polymorphonuclear leukocytes) and CD14-negative (B-cell lines, endothelial cells) cells. CD14, a 55-kDa glycosyl-phosphatidylinositol-anchored membrane protein present on mature myeloid cells, serves as a receptor for LPS in complex with a soluble (serum-derived) LPS-binding protein (LBP). In this report, we show that human umbilical vein endothelial cells (HUVEC), which do not express measurable CD14 protein, become 3000-fold more sensitive to LPS-induced activation in the presence of serum, as measured by activation of the transcription factor NF-kappaB and expression of mRNA encoding tissue factor, a procoagulant molecule. This enhanced responsiveness of HUVEC is specifically mediated by the cell-free pool of CD14 (soluble CD14, sCD14) found in serum. The role of sCD14 in HUVEC activation by LPS was established by (i) the blocking effect of monoclonal anti-CD14 antibodies which discriminate between cell-bound and sCD14, (ii) the lack of the serum-enhancing effect after immunodepletion of sCD14, and (iii) establishing a reconstituted system in which recombinant sCD14 was sufficient to enhance the effects of LPS in the absence of serum and without a requirement for LBP. Thus, this mechanism of endothelial cell activation by LPS involves a cell-free pool of sCD14 most likely shed from CD14-positive cells of the monocytic lineage.