Kuwano K, Hagimoto N, Nomoto Y, Kawasaki M, Kunitake R, Fujita M, Miyazaki H, Hara N
Research Institute for Diseases of the Chest, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Lab Invest. 1997 Feb;76(2):161-9.
The tumor suppresser p53 is a cell cycle checkpoint protein that contributes to the preservation of genetic stability by mediating either a G1 arrest or apoptosis in response to DNA damage. p53 causes growth arrest through transcriptional activation of the cyclin-dependent kinase inhibitor p21. During p53-mediated suppression of cell proliferation, p21 is important for coordinating cell cycle progression, DNA replication, and repair of damaged DNA. The purpose of this study is to investigate the expression of p53 and p21 mRNA in association with DNA damage and normal repair in acute immune complex alveolitis in mice. Male ICR mice were injected intravenously with IgG antibodies against oval albumin, aerosolized with oval albumin solution, and killed at 4, 6, 12, 24, and 48 hours and 1 week after aerosolization. We assessed the expression of p53 and p21 mRNA by reverse transcriptase (RT)-PCR and by RT in situ PCR. We also assessed DNA damage by terminal deoxynucleotidyl transferase mediated biotin-dUTP nick-end-labeling (TUNEL) and by gel electrophoresis of DNA extracted from lung tissues. The results of RT-PCR and RT in situ PCR showed that p53 and p21 mRNA were concurrently up-regulated at 4 to 48 hours after aerosolization in alveolar epithelial cells. Bronchial and alveolar epithelial cells were positively stained by TUNEL in this period but not at 1 week after aerosolization or in control mice. The result of electrophoretic analysis of DNA was compatible with that of TUNEL. These studies suggest that the responses of p53 and p21 mRNA are associated with physiologic processes of DNA damage and repair in acute immune complex alveolitis in mice.
肿瘤抑制因子p53是一种细胞周期检查点蛋白，通过介导G1期停滞或凋亡来响应DNA损伤，从而有助于维持遗传稳定性。p53通过细胞周期蛋白依赖性激酶抑制剂p21的转录激活导致生长停滞。在p53介导的细胞增殖抑制过程中，p21对于协调细胞周期进程、DNA复制和受损DNA修复非常重要。本研究的目的是调查小鼠急性免疫复合物肺泡炎中p53和p21 mRNA的表达与DNA损伤及正常修复的关系。雄性ICR小鼠静脉注射抗卵清蛋白IgG抗体，雾化吸入卵清蛋白溶液，并在雾化后4、6、12、24和48小时以及1周时处死。我们通过逆转录酶（RT）-PCR和RT原位PCR评估p53和p21 mRNA的表达。我们还通过末端脱氧核苷酸转移酶介导的生物素-dUTP缺口末端标记（TUNEL）和从肺组织提取的DNA的凝胶电泳评估DNA损伤。RT-PCR和RT原位PCR结果显示，雾化后4至48小时肺泡上皮细胞中p53和p21 mRNA同时上调。在此期间支气管和肺泡上皮细胞TUNEL染色呈阳性，但雾化后1周或对照小鼠中未出现阳性。DNA电泳分析结果与TUNEL结果一致。这些研究表明，p53和p21 mRNA的反应与小鼠急性免疫复合物肺泡炎中DNA损伤和修复的生理过程相关。
