Phorbol esters stimulate macropinocytosis and solute flow through macrophages.
Phorbol esters stimulate macropinocytosis and solute flow through macrophages.
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发表时间：
1989-09
影响因子：
4
通讯作者：
Joel A. Swanson
中科院分区：
文献类型：
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作者：
Joel A. Swanson
研究了骨髓源性巨噬细胞的胞饮作用的形态学和动力学，以确定佛波醇酯的刺激如何增加净溶质积累。佛波醇肉豆蔻酸酯乙酸酯（PMA）的应用程序增加了丰富的macropinosomes和溶质流经内吞隔室的速率。大的胞饮体起源于细胞边缘的皱褶，折叠在自身上，内化细胞外介质和溶质。我研究了刺激如何影响巨噬细胞中荧光染料荧光黄（LY）的胞饮流入、积累和随后流出的动力学。LY的积累及其随后的外排都是温度依赖性的，并且与细胞外介质中LY的浓度成正比。在PMA和LY中孵育2小时的巨噬细胞比单独在LY中的巨噬细胞积累了4到6倍的LY。如果在胞饮作用后，洗涤巨噬细胞并在未标记的培养基中重新孵育1小时追踪期，则一些内化的LY从细胞中分离出来。在追踪培养基中加入PMA增加了LY的外排。相比之下，一个较小的百分比LY是从巨噬细胞，这两个负载和追逐在PMA的存在下。这表明，尽管PMA增加了外排，但内流增加更多，因此更多通过胞饮进入的LY保留在细胞内。我认为，巨胞饮增加了胞饮体和外排囊泡之间的大小差异，并且这种差异大大增加了溶质的积累和通过内吞隔室的膜流量。
The morphology and kinetics of pinocytosis by bone marrow-derived macrophages were studied to determine how stimulation by phorbol esters increases net solute accumulation. Application of phorbol myristate acetate (PMA) increased both the abundance of macropinosomes and the rate of solute flow through the endocytic compartment. The large pinosomes originated as ruffles at the cell margins that folded back on themselves, internalizing extracellular medium and solutes. I examined how stimulation affects the kinetics of pinocytic influx, accumulation, and subsequent efflux of the fluorescent dye Lucifer Yellow (LY) in macrophages. Both the accumulation of LY and its subsequent efflux were temperature-dependent and directly proportional to the concentration of LY in the extracellular medium. Macrophages incubated in PMA and LY for 2 h accumulated four to six times more LY than did macrophages in LY alone. If after pinocytosis the macrophages were washed and reincubated in unlabeled medium for a 1 h chase period, some of the internalized LY was regurgitated from the cells. Inclusion of PMA in the chase medium increased efflux of LY. In contrast, a smaller percentage of LY was regurgitated from macrophages which were both loaded and chased in the presence of PMA. This indicates that although efflux is increased by PMA, influx increases more, and therefore more of the LY entering by pinocytosis is retained within the cell. I suggest that macropinocytosis increases the size difference between pinosomes and efflux vesicles, and that that difference increases greatly both solute accumulation and membrane flow through the endocytic compartment.