Niizuma Kuniyasu, Endo Hidenori, Nito Chikako, Myer D Jeannie, Chan Pak H
Department of Neurosurgery, Neurosurgical Laboratories, Stanford University School of Medicine, Stanford, Calif 94305-5487, USA.
Stroke. 2009 Feb;40(2):618-25. doi: 10.1161/STROKEAHA.108.524447. Epub 2008 Dec 18.
p53-upregulated modulator of apoptosis (PUMA), a BH3-only member of the Bcl-2 protein family, is required for p53-dependent and -independent forms of apoptosis. PUMA localizes to mitochondria and interacts with antiapoptotic Bcl-2 and Bcl-X(L) or proapoptotic Bax in response to death stimuli. Although studies have shown that PUMA is associated with pathomechanisms of cerebral ischemia, clearly defined roles for PUMA in ischemic neuronal death remain unclear. The purpose of this study was to determine potential roles for PUMA in cerebral ischemia.
Five minutes of transient global cerebral ischemia (tGCI) were induced by bilateral common carotid artery occlusion combined with hypotension.
PUMA was upregulated in vulnerable hippocampal CA1 neurons after tGCI as shown by immunohistochemistry. In Western blot and coimmunoprecipitation analyses, PUMA localized to mitochondria and was bound to Bcl-X(L) and Bax in the hippocampal CA1 subregion after tGCI. PUMA upregulation was inhibited by pifithrin-alpha, a specific inhibitor of p53, suggesting that PUMA is partly controlled by the p53 transcriptional pathway after tGCI. Furthermore, reduction in oxidative stress by overexpression of copper/zinc superoxide dismutase, which is known to be protective of vulnerable ischemic hippocampal neurons, inhibited PUMA upregulation and subsequent hippocampal CA1 neuronal death after tGCI.
These results imply a potential role for PUMA in delayed CA1 neuronal death after tGCI and that it could be a molecular target for therapy.
凋亡上调调节因子（PUMA）是Bcl-2蛋白家族中仅含BH3结构域的成员，在p53依赖和非依赖的凋亡形式中均发挥作用。PUMA定位于线粒体，并在死亡刺激下与抗凋亡蛋白Bcl-2和Bcl-X(L)或促凋亡蛋白Bax相互作用。尽管研究表明PUMA与脑缺血的发病机制相关，但PUMA在缺血性神经元死亡中的确切作用仍不清楚。本研究的目的是确定PUMA在脑缺血中的潜在作用。
通过双侧颈总动脉闭塞联合低血压诱导5分钟的短暂全脑缺血（tGCI）。
免疫组化显示，tGCI后易损的海马CA1神经元中PUMA表达上调。蛋白质印迹和免疫共沉淀分析表明，tGCI后海马CA1亚区的PUMA定位于线粒体，并与Bcl-X(L)和Bax结合。p53特异性抑制剂pifithrin-α可抑制PUMA的上调，提示tGCI后PUMA部分受p53转录途径调控。此外，过表达已知对易损缺血海马神经元具有保护作用的铜/锌超氧化物歧化酶来降低氧化应激，可抑制tGCI后PUMA的上调及随后的海马CA1神经元死亡。
这些结果表明PUMA在tGCI后延迟的CA1神经元死亡中可能发挥作用，并且它可能是一个治疗靶点。
