Effect of Bcl-2 on oxidant-induced cell death and intracellular Ca2+ mobilization
Effect of Bcl-2 on oxidant-induced cell death and intracellular Ca2+ mobilization
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DOI：
10.1152/ajpcell.1998.275.3.c832
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发表时间：
1998-09-01
影响因子：
5.5
通讯作者：
Amstad, PA
中科院分区：
文献类型：
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作者：
Ichimiya, M;Chang, SH;Amstad, PA
Bcl-2抑制细胞死亡的机制尚不清楚。有人认为Bcl-2是一种抗氧化剂。由于Bcl-2主要定位于内质网（ER）和线粒体的膜上，这代表了细胞内Ca 2+的主要储存位点，因此我们假设Bcl-2可能通过改变细胞内Ca 2+稳态来保护细胞免受氧化损伤。为了验证这一假设，我们研究了氧化剂处理对正常大鼠肾（NRK）细胞和在细胞内Ca 2+存在或不存在的情况下稳定转染Bcl-2的NRK细胞活力的影响，并比较了Bcl-2表达对氧化剂诱导的细胞内Ca 2+动员和对ER和线粒体Ca 2+池的影响。转染Bcl-2的NRK细胞（NRK-Bcl-2）对H2 O2诱导的细胞毒性的抵抗力显著高于对照细胞。EGTA-AM，细胞内的Ca 2+螯合剂，以及在培养基中的Ca 2+的情况下，减少H2 O2诱导的细胞毒性在两个细胞系。与对照组相比，过表达Bcl-2的细胞在H2 O2处理后细胞内Ca 2+浓度（[Ca 2 +]（i））的升高延迟。用钙离子载体离子霉素处理后，Bcl-2转染的细胞在最大上升后比对照细胞显示出更快的下降，这表明细胞内钙缓冲更强，而用毒胡萝卜素处理，ER Ca 2 +-ATP酶的抑制剂，在对照和Bcl-2转染的细胞中瞬时增加[Ca 2 +]（i）。使用氧化磷酸化解偶联剂对线粒体Ca 2+储存的估计表明，NRK-Bcl-2细胞具有比对照细胞更高的线粒体Ca 2+储存能力。总之，Bcl-2可以防止氧化剂诱导的细胞死亡，在一定程度上，通过增加线粒体的能力来存储Ca 2+。
The mechanism by which Bcl-2 inhibits cell death is unknown. It has been suggested that Bcl-2 functions as an antioxidant. Because Bcl-2 is localized mainly to the membranes of the endoplasmic reticulum (ER) and the mitochondria, which represent the main intracellular storage sites for Ca2+, we hypothesized that Bcl-2 might protect cells against oxidant injury by altering intracellular Ca2+ homeostasis. To test this hypothesis, we examined the effect of oxidant treatment on viability in normal rat kidney (NRK) cells and in NRK cells stably transfected with Bcl-2 in the presence or absence of intracellular Ca2+, and we compared the effect of Bcl-2 expression on oxidant-induced intracellular Ca2+ mobilization and on ER and mitochondrial Ca2+ pools. NRK cells transfected with Bcl-2 (NRK-Bcl-2) were significantly more resistant to H2O2-induced cytotoxicity than control cells. EGTA-AM, an intracellular Ca2+ chelator, as well as the absence of Ca2+ in the medium, reduced H2O2-induced cytotoxicity in both cell lines. Compared with controls, cells overexpressing Bcl-2 showed a delayed rise in intracellular Ca2+ concentration ([Ca2+](i)) after H2O2 treatment. After treatment with the Ca2+ ionophore ionomycin, Bcl-2-transfected cells showed a much quicker decrease after the maximal rise than control cells, suggesting stronger intracellular Ca2+ buffering, whereas treatment with thapsigargin, an inhibitor of the ER Ca2+-ATPases, transiently increased [Ca2+](i) in control and in Bcl-2-transfected cells. Estimates of mitochondrial Ca2+ stores using an uncoupler of oxidative phosphorylation show that NRK-Bcl-2 cells have a higher capacity for mitochondrial Ca2+ storage than control cells. In conclusion, Bcl-2 may prevent oxidant-induced cell death, in part, by increasing the capacity of mitochondria to store Ca2+.