Activation of elastin transcription by transforming growth factor-β in human lung fibroblasts
Activation of elastin transcription by transforming growth factor-β in human lung fibroblasts
复制标题
DOI：
10.1152/ajplung.00184.2006
复制
发表时间：
2007-04-01
影响因子：
4.9
通讯作者：
Goldstein, Ronald H.
中科院分区：
文献类型：
--
作者：
Kuang, Ping-Ping;Zhang, Xiao-Hui;Goldstein, Ronald H.
弹性蛋白的合成对于肺的发育和出生后的成熟以及损伤后的修复是必不可少的。通过北方分析评估，使用表达不可检测水平的弹性蛋白的人胚肺成纤维细胞，我们发现用外源性转化生长因子-β（TGF-β）处理诱导弹性蛋白异质核RNA（hnRNA）水平的快速和瞬时增加，随后弹性蛋白mRNA和蛋白质表达增加。在来自转基因小鼠的成纤维细胞中，TGF-β诱导了驱动氯霉素乙酰转移酶报告基因的人类弹性蛋白基因启动子片段表达的增加。通过TGF-β受体I抑制剂、全局转录抑制剂放线菌素D预处理，TGF-β对弹性蛋白hnRNA和mRNA表达的诱导被取消，通过加入蛋白质合成抑制剂放线菌酮部分阻断，但不受p44/42 MAPK抑制剂U 0126的影响。用p38 MAPK抑制剂SB- 203580预处理也部分减弱TGF-β诱导的弹性蛋白mRNA的水平，但不减弱其hnRNA。Western分析表明TGF-β刺激Akt磷酸化。LY-294002抑制磷脂酰肌醇3-激酶和Akt磷酸化，消除了TGF-β诱导的弹性蛋白hnRNA和mRNA表达增加。用白细胞介素-1 β或组蛋白去乙酰化酶抑制剂阿司他丁A处理肺成纤维细胞，通过抑制Akt磷酸化的机制抑制TGF-β诱导的弹性蛋白mRNA和hnRNA表达。采用小干扰RNA双链体下调Akt 2而非Akt 1表达阻断了TGF-β诱导的弹性蛋白hnRNA和mRNA水平的增加。总之，我们的研究结果表明，TGF-β激活弹性蛋白转录，这是依赖于磷脂酰肌醇3-激酶/ Akt活性。
Elastin synthesis is essential for lung development and postnatal maturation as well as for repair following injury. Using human embryonic lung fibroblasts that express undetectable levels of elastin as assessed by Northern analyses, we found that treatment with exogenous transforming growth factor-beta ( TGF-beta) induced rapid and transient increases in levels of elastin heterogeneous nuclear RNA ( hnRNA) followed by increases of elastin mRNA and protein expression. In fibroblasts derived from transgenic mice, TGF-beta induced increases in the expression of a human elastin gene promoter fragment driving a chloramphenicol acetyl transferase reporter gene. The induction of elastin hnRNA and mRNA expression by TGF-beta was abolished by pretreatments with TGF-beta receptor I inhibitor, global transcription inhibitor actinomycin D, and partially blocked by addition of protein synthesis inhibitor cycloheximide, but was not affected by the p44/42 MAPK inhibitor U0126. Pretreatment with the p38 MAPK inhibitor SB- 203580 also partially attenuated the levels of TGF-beta-induced elastin mRNA but not its hnRNA. Western analysis indicated that TGF-beta stimulated Akt phosphorylation. Inhibition of phosphatidylinositol 3-kinase and Akt phosphorylation by LY-294002 abolished TGF-beta- induced increases in elastin hnRNA and mRNA expression. Treatment of lung fibroblasts with interleukin-1 beta or the histone deacetylase inhibitor trichostatin A inhibited TGF-beta-induced elastin mRNA and hnRNA expression by a mechanism that involved inhibition of Akt phosphorylation. Downregulation of Akt2 but not Akt1 expression employing small interfering RNA duplexes blocked TGF-beta-induced increases of elastin hnRNA and mRNA levels. Together, our results demonstrated that TGF-beta activates elastin transcription that is dependent on phosphatidylinositol 3- kinase/ Akt activity.