Insulin-like growth factor-I signaling mechanisms, type I collagen and alpha smooth muscle actin in human fetal lung fibroblasts
Insulin-like growth factor-I signaling mechanisms, type I collagen and alpha smooth muscle actin in human fetal lung fibroblasts
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DOI：
10.1203/01.pdr.0000238257.15502.f4
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发表时间：
2006-10-01
影响因子：
3.6
通讯作者：
Nielsen, Heber C.
中科院分区：
文献类型：
--
作者：
Chetty, Anne;Cao, Gong-Jee;Nielsen, Heber C.
支气管壁重构是支气管肺发育不良(BPD)和哮喘患者氧化损伤的主要致病因素。假设：IGF-1促进发育中的肺成纤维细胞的α-平滑肌表达和胶原合成，从而通过核NF-B-k依赖的转录导致纤维化。我们通过将驱动荧光素酶基因的NF-B-k反应启动子导入HFLF，并用IGF-1(100 ng/mL)处理并检测荧光素酶活性，研究了对NF-B-k依赖的转录。在用IGF-1刺激细胞前一小时，我们将细胞暴露于PI-3激酶抑制剂或ERK1/2抑制剂。我们还使用IGF-1受体抗体来抑制IGF-1的作用，并研究其对α-SMA和I型胶原的影响。IGF-1处理显著提高了荧光素酶活性。这种作用可被PI-3和MAP-Kinase抑制剂减弱。Western印迹分析显示，PI-3激酶不依赖于L(K)B的磷酸化而介导了NF-B-k的IGF-1活化。我们发现，与总的NFKB相比，核提取液中磷酸化的NF-B-k的表达上调，表明IGF-1调节NF-B-k核转位下游的转录活性。LY294002和IGF-1受体抗体可显著抑制IGF-1诱导的α-SMA表达和I型胶原表达的增加。IGF-1细胞信号转导胎肺成纤维细胞合成胶原是通过PI3Kinase在HFLF中通过NF-B-k的作用而实现的。
Bronchial wall remodeling is a major morbidity component in oxidant injury in bronchopulmonary dysplasia (BPD) and asthma. Hypothesis: IGF-1 enhances alpha smooth muscle expression and collagen synthesis in developing lung fibroblasts leading to fibrosis through nuclear NF-B-k-dependent transcription. We studied NF-B-k dependent transcription by transfecting HFLF with a NF-B-k responsive promoter driving the luciferase gene and treating with IGF-1 (100 ng/mL) and measuring luciferase activity. We exposed cells to the PI-3 kinase inhibitor or the Erk1/2 inhibitor one hr before stimulatino with IGF-1. We also used IGF-1 receptor antibody to inhibit the action of IGF-1 and studied its effect on alpha-sma and type I collagen. IGF-1 treatment significantly increased luciferase activity. This was attenuated by PI-3 kinase and MAP-Kinase inhibitors. Western blot analysis showed PI-3 kinase mediates IGF-1 activation of NF-B-k independent of l(K)B phosphorylation. We found an up-regulation of phospho NF-B-k in the nuclear extract compared with total NFKB showing that IGF-1 regulates NF-B-k transcriptional activity downstream of NF-B-k nuclear translocation. IGF-1-induced increase in alpha-sma expression and type-I collagen was significantly inhibited by pretreatment with LY294002 and IGF-1 receptor antibody. IGF-1 cell signaling leading to collagen synthesis in fetal lung fibroblasts is mediated by PI3 Kinase acting through NF-B-k in HFLF.