Pérez-Rodríguez Rocío, Fuentes María P, Oliván Anna M, Martínez-Palacián Adoración, Roncero Cesáreo, González María P, Oset-Gasque María J
Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain.
J Neurosci Res. 2007 Aug 1;85(10):2224-38. doi: 10.1002/jnr.21342.
The aim of this work was to establish the possible involvement of mitochondria in the apoptotic event triggered by nitric oxide (NO) in chromaffin cells. Using bovine chromaffin cells in primary culture and several NO donors (SNP, SNAP, and GSNO) at apoptotic concentrations (50 microM-1 mM), we have shown that NO induces a time-dependent decrease in the mitochondrial transmembrane potential (DeltaPsi(m)), which correlates with the appearance of hypodiploid cells. Disruption in DeltaPsi(m) is followed by cytochrome c release to the cytosol, which in turn precedes caspase 3 activation. In this mechanism participates the Bcl-2 protein family, because NO donors downregulate the expression of anti-apoptotic members of the family such as Bcl-2 and Bcl-XL, and increase the expression of pro-apoptotic members, Bax and Bcl-Xs, inductors of cytochrome c release to cytosol. Different cell signaling pathways seem to regulate Bax induction and Bcl-2 inhibition because decreased Bcl-2 levels are detected later than enhanced Bax expression. The tumour suppressor protein p53 is also upregulated in a very early phase (30 min) of the NO-induced apoptosis and may be responsible for the further induction of Bax expression. Finally, the translocation of NF-kappaB to the nucleus seems to be another early event in NO-induced apoptosis and it may be involved in the regulation of p53 expression. These results support strongly the participation of mitochondrial mechanisms in NO-induced apoptosis in chromaffin cells and suggest that these cells may be good models for the investigation of molecular basis of neurodegeneration and neuroprotection.
这项工作的目的是确定线粒体是否可能参与嗜铬细胞中一氧化氮（NO）引发的凋亡事件。使用原代培养的牛嗜铬细胞和几种处于凋亡浓度（50微摩尔至1毫摩尔）的NO供体（SNP、SNAP和GSNO），我们已经表明，NO会导致线粒体跨膜电位（ΔΨm）随时间下降，这与亚二倍体细胞的出现相关。ΔΨm的破坏随后会导致细胞色素c释放到细胞质中，而这又先于半胱天冬酶3的激活。Bcl-2蛋白家族参与了这一机制，因为NO供体会下调该家族抗凋亡成员如Bcl-2和Bcl-XL的表达，并增加促凋亡成员Bax和Bcl-Xs的表达，Bax和Bcl-Xs是细胞色素c释放到细胞质中的诱导因子。不同的细胞信号通路似乎调节Bax的诱导和Bcl-2的抑制，因为检测到Bcl-2水平降低的时间晚于Bax表达增强的时间。肿瘤抑制蛋白p53在NO诱导的凋亡的非常早期阶段（30分钟）也会上调，可能负责进一步诱导Bax的表达。最后，NF-κB向细胞核的转位似乎是NO诱导的凋亡中的另一个早期事件，它可能参与p53表达的调节。这些结果有力地支持了线粒体机制参与嗜铬细胞中NO诱导的凋亡，并表明这些细胞可能是研究神经退行性变和神经保护分子基础的良好模型。
