Regulation of the rat NHE3 gene promoter by sodium butyrate
Regulation of the rat NHE3 gene promoter by sodium butyrate
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DOI：
10.1152/ajpgi.2001.281.4.g947
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发表时间：
2001-10-01
影响因子：
4.5
通讯作者：
Ghishan, FK
中科院分区：
文献类型：
--
作者：
Kiela, PR;Hines, ER;Ghishan, FK
短链脂肪酸，特别是丁酸盐（NaB），通过诱导结肠Na+/H+交换（NHE）刺激钠和水的吸收。NaB在体内和体外均诱导NHE 3活性以及蛋白质和mRNA表达。NaB作为组蛋白去乙酰化酶（HDAC）抑制剂，调节基因转录。因此，我们研究了NaB是否调节瞬时转染Caco-2细胞中大鼠NHE 3启动子的转录。NaB（5 mM）强烈刺激报告基因的活性，这种刺激被放线菌素D阻止，表明转录激活。NaB对NHE 3启动子的作用依赖于Ser/Thr激酶，特别是蛋白激酶A（PKA）的活性。然而，单独PKA刺激对启动子活性没有影响，并且它与NaB没有协同作用。另一种HDAC抑制剂曲古抑菌素A（TSA）以不依赖于Ser/Thr激酶的方式刺激NHE 3启动子。推测的NaB响应元件位于NHE 3启动子的-320/-34bp内。这些结果表明PKA介导了NaB对NHE 3基因转录的影响，NaB的作用机制与TSA不同。
Short-chain fatty acids, and especially butyrate (NaB), stimulate sodium and water absorption by inducing colonic Na+/H+ exchange (NHE). NaB induces NHE3 activity and protein and mRNA expression both in vivo and in vitro. NaB, as a histone deacetylase (HDAC) inhibitor, regulates gene transcription. We therefore studied whether NaB regulates transcription of the rat NHE3 promoter in transiently transfected Caco-2 cells. NaB (5 mM) strongly stimulated reporter gene activity, and this stimulation was prevented with actinomycin D, indicating transcriptional activation. NaB effects on the NHE3 promoter depended on the activity of Ser/Thr kinases, in particular, protein kinase A (PKA). However, PKA stimulation alone did not have an effect on promoter activity, and it did not act synergistically with NaB. Another HDAC inhibitor, Trichostatin A (TSA), stimulated NHE3 promoter in a Ser/Thr kinase-independent fashion. The putative NaB-responsive elements were localized within -320/-34 bp of the NHE3 promoter. These findings suggest that PKA mediates NaB effects on NHE3 gene transcription and that the mechanism of NaB action is different from that of TSA.