linc00520通过PDK1调控角质形成细胞分化及其在特应性皮炎皮损中的机制研究

The abnormal differentiation of keratinocyte has been demonstrated to be associated with the pathogenesis of atopic dermatitis. Previous studies indicate the long noncoding RNAs (lncRNAs) may play a part in the modulation of keratinocyte differentiation. Linc00520 was shown to promote the process of keratinocyte differentiation in the model of calcium-induced keratinocyte differentiation according to previous reports. Initial experiments have confirmed that linc00520 could physically bind to PDK1 and modulate the protein stability of PDK1. Hereby, we put out the hypothesis that linc00520 may enhance the protein-stabilizing effect of ubiquitination related enzyme on PDK1 and protect PDK1 from proteasome-mediated degradation, which increases the protein level of PDK1, thus promotes keratinocyte differentiation. This study will conduct research in the keratinocyte differentiation model and skin lesions of patients with atopic dermatitis. It will clarify the following issues: 1. The role of linc00520 in modulating PDK1 protein stability and subsequent keratinocyte differentiation; 2. The underlying molecular mechanism of the signaling axis linc00520/PDK1/ ubiquitination related enzyme in keratinocyte differentiation. In general, this study will cast light on the abnormal keratinocyte differentiation from the lncRNA perspective.

角质形成细胞的异常分化被证明与特应性皮炎发病相关，其中lncRNA参与调控角质形成细胞分化。本项目组前期研究发现在Ca2+诱导的角质形成细胞分化模型中linc00520促进角质形成细胞分化，但其中分子机制尚不明了。预实验结果证实linc00520可与PDK1结合并调节其蛋白稳定性，我们提出假说，linc00520可通过调节泛素化相关酶对PDK1蛋白的稳定作用，抑制PDK1的泛素化降解，提高PDK1蛋白表达水平，从而促进角质形成细胞的分化。本研究将利用人原代角质形成细胞分化模型及特应性皮炎皮损标本从以下两方面进行论证：①明确linc00520通过调节PDK1蛋白稳定性，进而调控角质形成细胞分化的作用；②探讨linc00520/PDK1/泛素化相关酶信号轴调控角质形成细胞分化的机制。综上，本研究将从lncRNA这个新视角揭示角质形成细胞异常分化的机制。

角质形成细胞的异常分化已被证明与皮肤疾病如特应性皮炎相关。目前关于lncRNA在角质形成细胞分化中的研究方兴未艾。前期研究利用芯片筛选了Ca2+诱导的角质形成细胞分化过程中相对于未分化组差异性表达的lncRNA。随着角质形成细胞分化，NR-037661表达水平逐渐升高。用构建了shRNA-NC及shRNA-NR_037661的腺病毒载体，分别转染角质形成细胞，并用钙离子刺激，提取两组的RNA后进行RNA-seq检测。筛选芯片结果中下调且在前期研究中随细胞分化过程逐渐上调的基因，发现GDF15、C15orf48、PRDM2、DDIT3、KLK5五个基因符合条件，目前在进一步验证中。NR-037661参与调节角质形成细胞分化，但其中分子机制有待于进一步研究。本研究将从lncRNA这个新视角为揭示角质形成细胞异常分化奠定基础。