Membrane capacitance changes associated with particle uptake during phagocytosis in macrophages
Membrane capacitance changes associated with particle uptake during phagocytosis in macrophages
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DOI：
10.1016/s0006-3495(98)77703-3
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发表时间：
1998-11-01
影响因子：
3.4
通讯作者：
Nelson, DJ
中科院分区：
文献类型：
--
作者：
Holevinsky, KO;Nelson, DJ
我们报告了使用电容测量来监测细胞暴露于吞噬刺激后的颗粒摄取。在这些研究中，人单核细胞来源的巨噬细胞(HMDM)和小鼠巨噬细胞样细胞系J774.1的细胞暴露于免疫复合物或大小(直径为0.8或3.2微米)的乳胶颗粒中。细胞暴露于免疫复合体后，细胞电容平均下降8pF。在免疫复合体暴露前用细胞松弛素B处理抑制颗粒摄取的细胞显示平均增加0.5pF。细胞暴露于颗粒刺激后，膜电容的下降与可溶性刺激、血小板激活因子无关，进一步证实了膜电容的下降是由于颗粒摄取。细胞暴露在大小的乳胶颗粒中会导致膜电容的逐步下降。从高斯拟合到步长幅度直方图计算，0.8微米颗粒的平均步长为250 fF，较大的3.2微米颗粒的平均步长变化为480 fF。基于包裹颗粒所需的最小膜量和比电容为10 fF/亩m(2)的单个颗粒的预测步长分别为20 fF和320 fF。较小颗粒的步长明显偏离预测的大小分布，这表明吞噬空泡的大小可能有一个下限，或者单个吞噬小体中摄取了多个颗粒。在许多细胞中观察到吞噬和胞吐之间的动态相互作用，这是一种双相反应，包括开始时电容的迅速增加，与细胞的胞吐一致，然后是电容的逐步减少。
We report the use of capacitance measurements to monitor particle uptake after cellular exposure to phagocytic stimuli. In these studies, human monocyte-derived macrophages (HMDMs) and cells from the murine macrophage-like cell line J774.1 were exposed to immune complexes or sized latex particles (0.8 or 3.2 mu m in diameter). An average decrease in cell capacitance of 8 pF was seen after exposure of the cells to immune complexes. Cells in which particle uptake was inhibited by cytochalasin B treatment before exposure to immune complexes showed an average increase of 0.5 pF. The decrease in membrane capacitance after exposure of cells to particulate stimuli was absent with the soluble stimulus, platelet-activating factor, further confirming that decreases in membrane capacitance were due to particle uptake. Exposure of cells to sized latex particles resulted in a graded, stepwise decrease in membrane capacitance. The average step size for 0.8-mu m particles was 250 fF, and the average step change for the larger 3.2-mu m particles was 480 fF, as calculated from Gaussian fits to the step size amplitude histograms. The predicted step size for the individual particles based upon the minimum amount of membrane required to enclose a particle and a specific capacitance of 10 fF/mu m(2) was 20 and 320 fF, respectively. The step size for the smaller particles deviates significantly from the predicted size distribution, indicating either a possible lower limit to the size of the phagocytic vacuole or multiple particles taken up within a single phagosome. Dynamic interaction between phagocytosis and exocytosis was observed in a number of cells as a biphasic response consisting of an initial rapid increase in capacitance, consistent with cellular exocytosis, followed by stepwise decreases in capacitance.