Hägerstrand H, Holmström T H, Bobrowska-Hägerstrand M, Eriksson J E, Isomaa B
Department of Biology, Abo Akademi University, Turku, Finland.
Mol Membr Biol. 1998 Apr-Jun;15(2):89-95. doi: 10.3109/09687689809027523.
Nonionic and anionic water-soluble amphiphiles were shown to increase strongly the binding of fluorescein isothiocyanate-conjugated annexin V (FITC-annexin V) in human erythrocytes pretreated with the aminophospholipid translocase (APLT) inhibitor n-ethylmaleimide (NEM). At high sublytic amphiphile-concentrations the binding of FITC-annexin V, monitored in a flow cytometer, was time- and temperature-dependent and occurred heterogeneously in the cell population, with 43-81% of cells being stained above background following incubation for 60 minutes at 37 degrees C. The increased FITC-annexin V binding apparently indicates an increased flop rate of phosphatidylserine (PS) to the outer membrane leaflet. When the NEM-pretreatment was omitted, the FITC-annexin V binding was markedly, but not completely, reduced. In erythrocytes incubated with a zwitter-ionic amphiphile, a small increase in FITC-annexin V binding was detected, while cationic amphiphiles did not induce an increased FITC-annexin V binding. The potency of amphiphiles to induce PS exposure was not related to the type of shape alteration or vesiculation induced. Our results indicate a significant role of the charge status of a membrane intercalated amphiphile for its capability to induce PS exposure.
已表明，非离子型和阴离子型水溶性两亲物能显著增强用氨基磷脂转位酶（APLT）抑制剂N-乙基马来酰亚胺（NEM）预处理的人红细胞中异硫氰酸荧光素偶联膜联蛋白V（FITC-膜联蛋白V）的结合。在高亚裂解浓度的两亲物条件下，通过流式细胞仪监测的FITC-膜联蛋白V的结合具有时间和温度依赖性，且在细胞群体中呈异质性发生，在37℃孵育60分钟后，43%-81%的细胞染色高于背景水平。FITC-膜联蛋白V结合增加显然表明磷脂酰丝氨酸（PS）外翻至外膜小叶的速率增加。当省略NEM预处理时，FITC-膜联蛋白V的结合明显但未完全减少。在用两性离子两亲物孵育的红细胞中，检测到FITC-膜联蛋白V结合略有增加，而阳离子两亲物未诱导FITC-膜联蛋白V结合增加。两亲物诱导PS暴露的能力与诱导的形状改变或囊泡形成类型无关。我们的结果表明，插入膜中的两亲物的电荷状态对其诱导PS暴露的能力具有重要作用。
