Yamaguchi Atsushi, Taniguchi Manabu, Hori Osamu, Ogawa Satoshi, Tojo Nobuteru, Matsuoka Nobuya, Miyake Shin-ichi, Kasai Kousuke, Sugimoto Hisashi, Tamatani Michio, Yamashita Toshihide, Tohyama Masaya
Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
J Biol Chem. 2002 Jan 4;277(1):623-9. doi: 10.1074/jbc.M107435200. Epub 2001 Oct 25.
Emerging evidence has shown that tumor suppressor p53 expression is enhanced in response to brain ischemia/hypoxia and that p53 plays a critical role in the cell death pathway in such an acute neurological insult. However the mechanism remains unclear. Recently it was reported that Peg3/Pw1, originally identified as a paternally expressed gene, plays a pivotal role in the p53-mediated cell death pathway in mouse fibroblast cell lines. In this study, we found that Peg3/Pw1 expression is enhanced in peri-ischemic neurons in rat stroke model by in situ hybridization analysis, where p53 expression was also induced by immunohistochemical analysis. Moreover, we found that p53 was co-localized with Peg3/Pw1 in brain ischemia/hypoxia by double staining analysis. In human neuroblastoma-derived SK-N-SH cells, Peg3/Pw1 mRNA expression is enhanced remarkably at 24 h post-hypoxia, when p53 protein expression was also enhanced at high levels. Subcellular localization of Peg3/Pw1 was observed in the nucleus. Adenovirus-mediated high dose p53 overexpression induced Peg3/Pw1 mRNA expression. Overexpression of Peg3/Pw1 reduced cell viability under hypoxic conditions, whereas that of the C-terminal-deleted mutant and anti-sense Peg3/Pw1 inhibited hypoxia-induced cell death. These results suggest that Peg3/Pw1 is involved in the p53-mediated cell death pathway as a downstream effector of p53 in brain ischemia/hypoxia.
新出现的证据表明，肿瘤抑制因子p53的表达在脑缺血/缺氧反应中增强，并且p53在这种急性神经损伤的细胞死亡途径中起关键作用。然而，其机制仍不清楚。最近有报道称，最初被鉴定为父系表达基因的Peg3/Pw1在小鼠成纤维细胞系的p53介导的细胞死亡途径中起关键作用。在本研究中，我们通过原位杂交分析发现，在大鼠中风模型的缺血周围神经元中，Peg3/Pw1的表达增强，免疫组化分析也显示p53表达在该处被诱导。此外，我们通过双重染色分析发现，在脑缺血/缺氧中p53与Peg3/Pw1共定位。在人神经母细胞瘤来源的SK-N-SH细胞中，缺氧后24小时Peg3/Pw1 mRNA表达显著增强，此时p53蛋白表达也高水平增强。观察到Peg3/Pw1在细胞核中的亚细胞定位。腺病毒介导的高剂量p53过表达诱导了Peg3/Pw1 mRNA表达。Peg3/Pw1的过表达在缺氧条件下降低了细胞活力，而C末端缺失突变体和反义Peg3/Pw1的过表达抑制了缺氧诱导的细胞死亡。这些结果表明，在脑缺血/缺氧中，Peg3/Pw1作为p53的下游效应物参与了p53介导的细胞死亡途径。
