Mechanism of nicotine-induced pulmonary fibroblast transdifferentiation
Mechanism of nicotine-induced pulmonary fibroblast transdifferentiation
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DOI：
10.1152/ajplung.00358.2004
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发表时间：
2005-10-01
影响因子：
4.9
通讯作者：
Torday, JS
中科院分区：
文献类型：
--
作者：
Rehan, VK;Wang, Y;Torday, JS
我们验证了一种假设，即在体外尼古丁暴露扰乱了特定的上皮-间充质旁分泌信号通路，导致肺间质脂肪纤维母细胞(LIF)到肌纤维母细胞(MYF)的转分化，从而导致肺发育和功能的改变。本研究旨在探讨尼古丁是否诱导LIF-to-MYF转分化，并阐明其潜在的分子机制(S)，以及是否可以通过刺激特定的肺泡间质成纤维细胞成脂途径来阻止尼古丁诱导的LIF-MYF转分化。人胚肺成纤维细胞系WI38细胞用尼古丁加或不加肺泡成纤维细胞成脂途径特异性激动剂PTHrP、DBcAMP或PPARγ激动剂罗格列酮(RGZ)处理7d。用RT-PCR、Western杂交和免疫组织化学方法检测关键的生脂和生肌标记物的表达。测定了尼古丁对WI38细胞摄取甘油三酯及其受体结合PTHrP的影响。最后，将PPAR-γ表达载体导入WI38细胞，观察其对尼古丁诱导的LIF-MYF转分化的影响。尼古丁诱导LIF向MYF转分化，成脂细胞表达明显减少，肌源性标志物表达增加，且呈剂量依赖性。伴随而来的是PTHrP受体与其受体结合的减少。联合应用PTHrP、DBcAMP、RGZ和瞬时过表达PPARγ可完全阻止尼古丁诱导的LIF到MYF的转分化。我们的数据提示尼古丁通过下调成脂的PTHrP介导的cAMP依赖的PKA信号通路来诱导肺泡LIF到MYF的转分化，这一机制可以通过特定的分子靶点来阻止。这些观察结果对子宫内尼古丁诱导的肺损伤的潜在治疗意义仍有待测试。
We tested the hypothesis that in vitro nicotine exposure disrupts specific epithelial-mesenchymal paracrine signaling pathways and results in pulmonary interstitial lipofibroblast (LIF)-to-myofibroblast (MYF) transdifferentiation, resulting in altered pulmonary development and function. Studies were done to determine whether nicotine induces LIF-to-MYF transdifferentiation and to elucidate underlying molecular mechanism(s) involved and to determine whether nicotine-induced LIF-to-MYF transdifferentiation could be prevented by stimulating specific alveolar interstitial fibroblast lipogenic pathway. WI38 cells, a human embryonic pulmonary fibroblast cell line, were treated with nicotine with or without specific agonists of alveolar fibroblast lipogenic pathway, PTHrP, DBcAMP, or the potent PPAR gamma stimulant rosiglitazone (RGZ) for 7 days. Expression of key lipogenic and myogenic markers was examined by RT-PCR, Western hybridization, and immunohistochemistry. The effect of nicotine on triglyceride uptake by WI38 cells and PTHrP binding to its receptor was also determined. Finally, the effect of transfecting WI38 cells with a PPAR gamma expression vector on nicotine-induced LIF-to-MYF transdifferentiation was determined. Nicotine treatment resulted in significantly decreased expression of lipogenic and increased expression of myogenic markers in a dose-dependent manner, indicating nicotine-induced LIF-to-MYF transdifferentiation. This was accompanied by decreased PTHrP receptor binding to its receptor. The nicotine-induced LIF-to-MYF transdifferentiation was completely prevented by concomitant treatment with PTHrP, DBcAMP, RGZ, and by transiently overexpressing PPAR gamma. Our data suggest nicotine induces alveolar LIF-to-MYF transdifferentiation through a mechanism involving downregulation of lipogenic PTHrP-mediated, cAMP-dependent PKA signaling pathway, which can be prevented using specific molecular targets. Potential therapeutic implications of these observations against in utero nicotine-induced lung injury remain to be tested.