Preferential redistribution of lipoprotein-unassociated apoA-IV to an HDL subpopulation with a high degree of LCAT modification.
Preferential redistribution of lipoprotein-unassociated apoA-IV to an HDL subpopulation with a high degree of LCAT modification.
复制标题
与脂蛋白无关的 apoA-IV 优先重新分配至具有高度 LCAT 修饰的 HDL 亚群。
作者：
Lefevre,M;Goudey-Lefevre,JC;Roheim,PS
在体外研究了LCAT介导的HDL修饰与脂蛋白非相关apoA-IV向HDL再分布的关系。将免疫亲和分离的大鼠脂蛋白不相关的apoA-IV添加到apoB-， apoE-， apoA-IV耗尽，[3H]胆固醇标记的大鼠血浆中，并在37°C下孵育。添加与脂蛋白无关的apoA-IV导致胆固醇酯化率适度（10%）但显著降低。在活性LCAT存在的情况下进行孵育，导致抗apoa - iv免疫亲和柱保留的3h标记量呈时间依赖性增加。抗apoa - iv免疫亲和柱保留的脂蛋白比未保留的脂蛋白（30分钟酯化率19%）经历了更大的[3H]胆固醇到[3H]胆固醇酯的转化（30分钟酯化率48%）。这些数据表明，在LCAT诱导的胆固醇酯化过程中，脂蛋白不相关的apoA-IV转移到高密度脂蛋白亚群，该亚群被LCAT修饰的程度大于剩余的高密度脂蛋白。进一步的数据分析表明48%的胆固醇酯化足以使apoA-IV被安置在HDL颗粒的表面。
The relationship between LCAT mediated HDL modification and the redistribution of lipoprotein-unassociated apoA-IV to HDL was investigatedin vitro. Immunoaffinity-isolated rat lipoprotein-unassociated apoA-IV was added to apoB-, apoE-, apoA-IV depleted, [3H]cholesterol labelled rat plasma and incubated at 37°C. The addition of lipoprotein-unassociated apoA-IV resulted in a modest (10%) but significant reduction in the rate of cholesterol esterification. Incubations conducted in the presence of active LCAT led to a time-dependent increase in the amount of the3H label retained by an anti-apoA-IV immunoaffinity column. Lipoproteins retained by the anti-apoA-IV immunoaffinity column had experienced a greater conversion of [3H]cholesterol to [3H]cholesteryl esters (48% esterification at 30 min) than the unretained lipoproteins (19% esterification at 30 min). These data suggest that during the course of LACT-induced cholesterol esterification, lipoprotein-unassociated apoA-IV transfers to a subpopulation of HDL which has been modified by LCAT to a greater extent than the remaining HDL. Further analysis of the data demonstrates that 48% cholesterol esterification is sufficient to allow apoA-IV to be accommodated on the surface of an HDL particle.