Phagocytosis of nonapoptotic cells dying by caspase-independent mechanisms
Phagocytosis of nonapoptotic cells dying by caspase-independent mechanisms
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DOI：
10.4049/jimmunol.164.12.6520
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发表时间：
2000-06-15
影响因子：
4.4
通讯作者：
Leist, M
中科院分区：
文献类型：
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作者：
Hirt, UA;Gantner, F;Leist, M
Caspase 激活、质膜外表面磷脂酰丝氨酸 (PS) 暴露以及快速吞噬死亡细胞是细胞凋亡的关键特征，非凋亡/坏死死亡模式的发生与 Caspase 激活无关，但吞噬作用的作用很大程度上未知。为了解决这个问题，我们研究了人单核细胞源性巨噬细胞（HMDM）和大鼠小胶质细胞的吞噬作用。通过几种不同的方法刺激靶细胞（Jurkat），所有这些方法都会导致不依赖于半胱天冬酶的死亡。首先，我们通过将毒素与 ATP 消耗剂结合来诱导坏死。在这些条件下，PS 既没有暴露，这些细胞在死亡前也没有被吞噬。然而，一旦质膜完整性丧失，死亡细胞就会被HMDM快速有效地吞噬，接下来，我们在泛半胱天冬酶抑制剂zVAD-fmk存在的情况下用十字孢菌素触发Jurkat细胞死亡，在这些条件下，死亡是通过延迟坏死发生的，并且没有暴露BS，尽管如此，这种致命性攻击的细胞在膜完整性丧失之前就被吞噬了。最后，我们分别用离子载体触发 Jurkat 细胞中的 Ca2+ 流入，或通过刺激谷氨酸受体触发神经元中的 Ca2+ 流入。在这两个模型中，PS 都暴露在细胞表面。 Ca2+应激细胞在刺激后30分钟开始被吞噬。蛋白激酶 C 抑制剂可阻止 Ca2+ 介导的 PS 暴露和吞噬作用。本质上，对于所有具有 HMDM 和小胶质细胞的模型都获得了类似的吞噬数据，我们得出结论，非凋亡且独立于 caspase 激活的细胞也可以在膜裂解之前或之后很快被识别和去除。
Caspase activation, exposure of phosphatidylserine (PS) on the outer surface of the plasma membrane, and rapid phagocytic removal of dying cells are key features of apoptosis, Nonapoptotic/necrotic modes of death occur independent of caspase activation, but the role of phagocytosis is largely unknown. To address this issue, we studied phagocytosis by human monocyte-derived macrophages (HMDM) and rat microglial cells. Target cells (Jurkat) were stimulated by several different methods that all caused caspase-independent death. First, we induced necrosis by combining toxins with ATP-depleting agents. Under these conditions, neither PS was exposed nor were such cells phagocytosed before their death. However, once the plasma membrane integrity was lost, the dead cells were rapidly and efficiently engulfed by HMDM, Next, we triggered Jurkat cell death with staurosporine in the presence of the pan-caspase inhibitor zVAD-fmk, Under these conditions, death occurred by delayed necrosis and without exposure of BS, Nevertheless, such lethally challenged cells were phagocytosed before the loss of membrane integrity. Finally, we triggered Ca2+ influx in Jurkat cells with an ionophore, or in neurons by glutamate receptor stimulation, respectively. In both models, PS was exposed on the cell surface. Ca2+-stressed cells were phagocytosed starting at 30 min after stimulation. Protein kinase C inhibitors prevented Ca2+-mediated PS exposure and phagocytosis. Essentially, similar phagocytosis data were obtained For all models with HMDM and microglia, We conclude that also cells dying nonapoptotically and independent of caspase activation may be recognized and removed before, or very quickly after, membrane lysis.