Primary Porcine Kupffer Cell Phagocytosis of Human Platelets Involves the CD18 Receptor
Primary Porcine Kupffer Cell Phagocytosis of Human Platelets Involves the CD18 Receptor
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DOI：
10.1097/tp.0b013e31822bc986
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发表时间：
2011-10-15
期刊：
影响因子：
6.2
通讯作者：
Burlak, Christopher
中科院分区：
文献类型：
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作者：
Chihara, Ray K.;Paris, Leela L.;Burlak, Christopher
背景。肝衰竭已成功地治疗临床体外灌注猪肝。然而，狗到猪和猪到狒狒的肝脏异种移植模型导致肝脏异种移植引起的血小板减少症继发严重出血。库普弗细胞（KC）是肝脏中大量存在的吞噬细胞。KC表达CD11b/CD18受体，该受体通过与血小板表面蛋白和碳水化合物的相互作用参与冷冻血小板结合和吞噬。我们试图确定KC CD18在肝脏异种移植诱导的血小板减少症中的作用。用流式细胞术、免疫印迹和定量聚合酶链反应对原代猪KC进行了表征。猪KC用荧光标记的人血小板进行抑制试验。CD18受体是siRNA敲除的靶标。通过定量聚合酶链反应和流式细胞术检测，国产和α 1,3-半乳糖转移酶双敲除的猪KC培养物CD18阳性约92%。使用CD18阻断抗体可减少人血小板结合和吞噬。此外，asialalofetuin，而不是fetuin，抑制血小板吞噬，提示参与寡糖结合位点。此外，通过siRNA降低CD18的表达可降低人血小板结合。我们的数据表明，原代猪KC结合并吞噬CD18参与的人血小板。进一步了解和修饰CD18在猪体内的表达可能会导致减少血小板减少作用的异种肝脏移植，这可以作为异体肝移植的桥梁。
Background. Hepatic failure has been treated successfully with clinical extracorporeal perfusions of porcine livers. However, dog-to-pig and pig-to-baboon liver xenotransplant models have resulted in severe bleeding secondary to liver xenograft-induced thrombocytopenia. Kupffer cells (KC) are abundant phagocytic cells in the liver. KC express the CD11b/CD18 receptor, which has been implicated in chilled platelet binding and phagocytosis through interaction with platelet surface proteins and carbohydrates. We sought to identify the role of KC CD18 in liver xenograft-induced thrombocytopenia.Methods. Primary pig KC were characterized by flow cytometry, immunoblots, and quantitative polymerase chain reaction. Pig KC were used in inhibition assays with fluorescently labeled human platelets. The CD18 receptor was targeted for siRNA knockdown.Results. Domestic and alpha 1,3-galactosyltransferase double knockout porcine KC cultures were approximately 92% positive for CD18 as detected by quantitative polymerase chain reaction and flow cytometry. Use of CD18 blocking antibodies resulted in reduction of human platelet binding and phagocytosis. Additionally, asialofetuin, not fetuin, inhibited platelet phagocytosis suggesting the involvement of an oligosaccharide-binding site. Furthermore, reduced CD18 expression by siRNA resulted in decreased human platelet binding.Conclusions. Our data suggest that primary pig KC bind and phagocytose human platelets with involvement of CD18. Further understanding and modification of CD18 expression in pigs may result in a liver xenograft with reduced thrombocytopenic effects, which could be used as a bridge to allogeneic liver transplantation.