INTERVENTION OF AUTOANTIBODY IN THE MEMBRANE PHOSPHOLIPID FLIP-FLOP OF TROPHOBLAST CELLS.

抗磷脂抗体是一种与抗磷脂综合征(APS)相关的自身抗体，表现为动、静脉血栓形成、血小板减少和复发性胎儿丢失。这些并发症的潜在机制尚不完全清楚，但显然是由于加速凝血所致。由于在细胞凋亡和滋养细胞分化过程中，可能触发凝血的负电荷磷脂磷脂酰丝氨酸暴露在质膜的外叶中，因此我们重点研究了与负电荷磷脂结合的蛋白质，以揭示APS的发病机制。制备了以辛基纤维素包埋心磷脂或磷脂酰丝氨酸的亲和层析柱，用2M氯化钠洗脱收集与这些磷脂结合的血浆蛋白。用ID或2D电泳法分离A蛋白，然后用多肽质量指纹图谱进行鉴定。这些蛋白包括β2糖蛋白I、α-胰酶抑制因子家族重链相关蛋白(IHRP)、补体因子4、H因子和H因子相关蛋白I。H因子的结合很有趣，因为H因子突变导致溶血性尿毒症综合征，其病理特征是肾微血管血栓形成，APS也会发生这种情况。最近，有关替代补体途径激活的重要作用已有报道。因此，作为一种替代途径的调节蛋白，因子H可能参与了APS的发病机制。

Antiphospholipid antibody is an autoantibody associated with antiphospholipid syndrome (APS) representing arterial and venous thrombosis, thrombocytopenia, and recurrent fetal loss. The underlying mechanism of these complications is not fully understood, while they are obviously due to accelerated coagulation. Since a negatively charged phospholipid, phosphatidylserine, which potentially triggers blood coagulation, is exposed to the outer leaflet of plasma membrane during apoptosis and trophoblast differentiation, we focused on the proteins binding to negatively charged phospholipids in order to delineate the pathogenesis of APS. An affinity column, in which cardiolipin or phosphatidylserine was embedded in octyl cellulose was prepared, and the plasma proteins bound to these phospholipids were collected by elution with 2M NaCl. A proteins were separated by iD or 2D electrophoresis, and then identified by peptide mass fingerprinting. The proteins included beta2 glycoprotein I, inter-alpha-trypsin inhibitor family heavy chain-related protein (IHRP), complement factor 4, factor H and factor H-related protein I. The binding of factor H was interesting, since factor H mutations cause hemolytic uremic syndrome with characteristic pathology of renal microvascular thrombosis, which also occurs in APS. Recently, the crucial role of alternative complement pathway activation has been reported. Thus, possible involvement of factor H, a regulatory protein of alternative pathway, would be an attractive speculation to delineate the pathogenesis of APS.