LincRNA-p21对PTEN乙酰化修饰在抗肺纤维化中的作用和机制

Pulmonary fibrosis is a final common pathological phenotype of numerous of human lung diseases or systemic diseases, unfortunately there is no efficient treatment to date. It has been reported that PTEN (Phosphatase and tensin homolog), a tumor suppressor, has a function of antifibrosis, phosphorylayion is an active status of PTEN in antifibrosis. About 7% genomes encode large intergenic non-coding RNA, name as LincRNA. They associate with numerous of human diseases. In our prelimited data we showed that LincRNA-p21 expression is low in pulmonary fibrosis patients; in bleomycin lung fibrosis model, transgenic mouse and human ILD lung fibroblast, we found that antifibrotic function of PTEN relies on its acetylation, we also found that LincRNA-p21 acetylates PTEN, and result in inhibition of TGFβ-stimulated fibrosis process. The aims of this project are to demonstrate that PTEN phosphorylation in antifibrosis rely on its acetylation, to determined that LincRNA-p21 antifibrosis in lung is via PTEN acetylation. The discovery that LincRNA-p21 is directly involved in regulation of PTEN acetylation in addition to its well know role as antifibrosis broadens the functional range of this regulatory molecule and suggests that PTEN should also be called a 'fibrosis suppressor'. The LincRNA-p21 rescue analyses proposed in this aim would reveral the phonetypic changes of lung fibrosis directly related to the reduced levels of LincRNA-p21. We expect that normalization of LincRNA-p21 levels would, at least partially, normalize the 'activated status'of lung fibroblast. Thus LincRNA-p21 may represent an ideal target for treatment of lung fibrosis and other fibrotic diseases. Furthermore, our studies, which would further characterize the function of LincRNA-p21 as an antifibrotic agent, would be particularly relevant for the possible future therapeutic application of this agent.

肺纤维化是一组由多种肺部或全身性疾病所致的一种严重的终结病理状况，机制不明，尚无有效治疗手段。肿瘤抑制因子PTEN具有抗纤维化作用，磷酸化是PTEN抗纤维化的活性状态。人类基因组中约7%产生的转录本是长链非编码RNA(LincRNA），它们与多种疾病的发生密切相关。我们研究表明肺纤维化病人LincRNA-p21表达明显下降；LincRNA-p21对TGFβ刺激的纤维化进程有抑制作用；PTEN的抗肺纤维化作用依赖于PTEN的乙酰化修饰，而LincRNA-p21有促PTEN乙酰化的作用。本课题拟利用转基因小鼠，体外培养的肺纤维母细胞和大量的临床标本，以LincRNA-p21调节PTEN乙酰化修饰为切入点，确定（1）LincRNA-p21通过PTEN乙酰化在抗肺纤维化中的作用及机制，（2）乙酰化在PTEN磷酸化中的作用。研究结果将有助于阐明肺纤维化发病机制并为寻找新的药物治疗靶点提供理论依据。

肺纤维化是一组由多种肺部或全身性疾病所致的一种严重的终结病理状况，机制不明，尚无有效治疗手段。肿瘤抑制因子PTEN具有抗纤维化作用，磷酸化是PTEN抗纤维化的活性状态。人类基因组中约7%产生的转录本是长链非编码RNA(LincRNA），它们与多种疾病的发生密切相关。我们研究表明肺纤维化病人LincRNA-p21表达明显下降；LincRNA-p21对TGFβ刺激的纤维化进程有抑制作用；PTEN的抗肺纤维化作用依赖于PTEN的乙酰化修饰，而LincRNA-p21有促PTEN乙酰化的作用。本课题拟利用转基因小鼠，体外培养的肺纤维母细胞和大量的临床标本，以LincRNA-p21调节PTEN乙酰化修饰为切入点，确定（1）LincRNA-p21通过PTEN乙酰化在抗肺纤维化中的作用及机制，（2）乙酰化在PTEN磷酸化中的作用。结果表明，肺纤维化病人肺组织中高表达a-SMA而LincRNA-p21处于第水平。LincRNA-p21对PTEN乙酰化和PTEN磷酸化有促进作用，对TGF-β刺激产生胶原蛋白，α-SMA等的干扰作用。然而，PCAF促进PTEN的乙酰化和磷酸化有抑制作用。同时观察到上述情况时TGF-β刺激CTGF，胶原蛋白，α-SMA被抑制。基因芯片结果显示肺纤维化病人相对于正常人LincRNA-p21明显降低。另外，在肺纤维化病人肺静脉内皮细胞a-SMA明显堆积；在ILD模型鼠肺静脉内皮细胞a-SMA表达增加。实验中观察到，TGF-β可刺激肺上皮细胞表达a-SMA。敲低LincRNA-p21时，促进a-SMA的表达，还可抑制磷酸化eNOS的水平。在肺纤维化病人血管内皮自噬相关蛋白表达下降，TGF-β抑制原代培养的肺上皮细胞LC3BI/II的表达同时上调p62的水平。LincRNA-p21阻断TGF-β对自噬的抑制作用，TGF-β抑制肺静脉内皮细胞磷酸化NO的水平，同时，过表达的a-SMA抑制LL29细胞生长。研究结果将有助于阐明肺纤维化发病机制并为寻找新的药物治疗靶点提供理论依据。