CD24 is a marker of exosomes secreted into urine and amniotic fluid
CD24 is a marker of exosomes secreted into urine and amniotic fluid
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DOI：
10.1038/sj.ki.5002486
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发表时间：
2007-11-01
影响因子：
19.6
通讯作者：
Altevogt, P.
中科院分区：
文献类型：
--
作者：
Keller, S.;Rupp, C.;Altevogt, P.
Exosome是一种小的膜小泡，从各种类型的细胞分泌到各种体液中，包括血液和尿液。这些囊泡被认为在细胞间的相互作用中发挥作用。CD24是一种小而广泛的糖基化蛋白，通过糖基磷脂酰肌醇锚点连接到细胞表面。在这项研究中，我们发现CD24存在于膜小泡中，其特征是从正常人的尿液中分离出来的外体。CD24在肾小管细胞和足细胞中均有表达，用胆固醇萃取剂处理足细胞，而不用钙离子载体处理足细胞，可导致含有CD24的外切体的释放。使用CD24作为标记，我们在新生儿的尿液和孕妇的羊水中发现了外切体，在小鼠身上也发现了类似的发现。有趣的是，对CD24基因敲除小鼠的研究表明，外切体是从胎儿释放出来的，但不是从母亲那里释放的；然而，外切体释放在敲除小鼠和野生型小鼠中是相似的。这表明CD24对外切体的形成或释放不是必需的，但可能是一个方便的外切体标记。我们的研究表明，胚胎肾脏的胞外体分泌可能在胎儿-母体间期发挥生物学作用。
Exosomes are small membrane vesicles that are secreted from a variety of cell types into various body fluids including the blood and urine. These vesicles are thought to play a role in cell-cell interactions. CD24 is a small but extensively glycosylated protein linked to the cell surface by means of a glycosyl-phosphatidylinositol anchor. In this study we found that CD24 is present in membrane vesicles characterized as exosomes that were isolated from the urine of normal individuals. CD24 was expressed by both tubule cells and podocytes and treatment of the latter with a cholesterol-extracting agent, but not with a calcium ionophore, caused the release of CD24-containing exosomes. Using CD24 as a marker, we found exosomes in the urine of newborn infants and in the amniotic fluid of pregnant women with similar findings made in mice. Interestingly, studies with CD24 knockout mice showed that the exosomes are released from the fetus but not from the mother; however, exosome release was similar from both the knockout and the wild-type mice. This indicates that CD24 is not essential for exosome formation or release but may be a convenient exosome marker. Our studies suggest that exosomal secretion from the embryonic kidney could play a biological role at the fetal-maternal interphase.