Protection of renal inner medullary epithelial cells from apoptosis by hypertonic stress-induced p53 activation
Protection of renal inner medullary epithelial cells from apoptosis by hypertonic stress-induced p53 activation
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DOI：
10.1074/jbc.m000522200
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发表时间：
2000-06-16
影响因子：
4.8
通讯作者：
Burg, M
中科院分区：
文献类型：
--
作者：
Dmitrieva, N;K端ltz, D;Burg, M
急性高渗导致小鼠肾髓内集管细胞（mIMCD3）细胞周期延迟和凋亡，并增加GADD45的表达。由于肿瘤抑制蛋白p53可能参与了这些作用，我们研究了p53在mIMCD3对高渗应激反应中的作用。NaCl的加入使渗透压从对照水平320 mosmol/kg急剧升高到500-600 mosmol/kg，在15分钟内使总水平和丝氨酸（15）磷酸化的p53水平显著升高。然而，类似的尿素渗透压升高并没有增加p53水平。我们的研究表明，诱导的p53具有转录活性，是因为添加500-600 mmol /kg的NaCl刺激了含有p53共识元件的荧光素酶报告基因的转录，并适当改变了p53已知转录靶点的mRNA水平，即增加了MDM-2，降低了BCL-2水平。当NaCl浓度进一步升高至700-800 mosmol/kg时，大部分细胞通过凋亡迅速死亡。在较高的NaCl浓度下，p53水平进一步升高，但Ser（15）磷酸化和转录活性显著低于500-600 mosmol/kg时的水平。在nacl诱导的500 mosmol/kg水平下，存在对照的非特异性寡核苷酸时，细胞凋亡很少发生，但在添加p53反义寡核苷酸时，细胞凋亡高度普遍，这大大降低了p53水平。我们得出结论，高渗应激诱导mIMCD3细胞中的p53活性有助于细胞存活。
Acute hypertonicity causes cell cycle delay and apoptosis in mouse renal inner medullary collecting duct cells (mIMCD3) and increases GADD45 expression. Be cause the tumor suppressor protein p53 may be involved in these effects, we have investigated the role of p53 in mIMCD3 response to hyperosmotic stress. Acute elevation of osmolality with NaCl addition from the control level of 320 mosmol/kg to 500-600 mosmol/kg greatly increased the levels of total and Ser(15)-phosphorylated p53 within 15 min. However, similar elevation of osmolality with urea did not increase p53 levels. Our studies indicate that induced p53 is transcriptionally active because NaCl addition to 500-600 mosmol/kg stimulated transcription of a luciferase reporter containing a p53 consensus element and appropriately altered mRNA levels of known transcriptional targets of p53, i.e. increased MDM-2 and decreased BCL-2 levels. Elevating NaCl further to 700-800 mosmol/kg rapidly killed most of the cells by apoptosis, At these higher NaCl concentrations, p53 levels were further increased although Ser(15) phosphorylation and transcriptional activity were significantly lower than levels at 500-600 mosmol/kg. At NaCl-induced 500 mosmol/kg, apoptosis was rare in the presence of control, nonspecific oligonucleotide but highly prevalent upon addition of p53 antisense oligonucleotide that substantially reduced p53 levels. We conclude that induction of active p53 in mIMCD3 cells by hypertonic stress contributes to cell survival.