Sequence of Physical Changes to the Cell Membrane During Glucocorticoid-Induced Apoptosis in S49 Lymphoma Cells
Sequence of Physical Changes to the Cell Membrane During Glucocorticoid-Induced Apoptosis in S49 Lymphoma Cells
复制标题
DOI：
10.1016/j.bpj.2008.12.3925
复制
发表时间：
2009-04-08
影响因子：
3.4
通讯作者：
Bell, John D.
中科院分区：
文献类型：
--
作者：
Bailey, Rachel W.;Nguyen, Thaothanh;Bell, John D.
在细胞凋亡过程中，质膜的物理变化使细胞为吞噬细胞的清除和分泌性磷脂酶 A(2) (sPLA(2)) 的水解做好准备。这些变化之间的关系尚未充分确定，特别是对于激素刺激的细胞凋亡。本研究解决了糖皮质激素诱导的 S49 淋巴瘤细胞凋亡的这些问题。使用流式细胞术、显微镜和荧光光谱来评估在不存在和存在 sPLA(2) 的情况下部花青 540 发射、劳丹广义偏振、磷脂酰丝氨酸暴露、半胱天冬酶激活和膜对碘化丙啶的通透性。观察到的最早的事件是细胞半胱天冬酶的激活。膜探针的结果表明，在细胞凋亡早期，脂间间距也会增加，并且先于磷脂酰丝氨酸的跨双层迁移、DNA 片段化以及与细胞起泡和溶解相关的脂质顺序的普遍增加。 sPLA(2) 的活性似乎更多地与脂质间距相关，而不是与膜不对称性的丧失相关。其中一些事件的早期性质及其促进促炎酶活性的能力表明 T 淋巴细胞凋亡期间炎症反应的可能性。
During apoptosis, physical changes in the plasma membrane prepare the cell for clearance by phagocytes and hydrolysis by secretory phospholipase A(2) (sPLA(2)). The relationships among these changes have not been adequately established, especially for hormone-stimulated apoptosis. This study addresses these issues for glucocorticoid-induced apoptosis in S49 lymphoma cells. Flow cytometry, microscopy, and fluorescence spectroscopy were used to assess merocyanine 540 emission, laurdan generalized polarization, phosphatidylserine exposure, caspase activation, and membrane permeability to propidium iodide in the absence and presence of sPLA(2). The earliest event observed was activation of cellular caspases. Results with membrane probes suggest that interlipid spacing also increases early during apoptosis and precedes transbilayer migration of phosphatidylserine, DNA fragmentation, and a general increase in lipid order associated with blebbing and dissolution of the cells. The activity of sPLA(2) appeared to be linked more to lipid spacing than to loss of membrane asymmetry. The early nature of some of these events and their ability to promote activity of a proinflammatory enzyme suggests the possibility of an inflammatory response during T-lymphocyte apoptosis.