皮肤老化旁观者效应的机制研究：分泌型miRNAs对端粒途径的调控作用

The skin aging bystander effect is a recently discovered phenomenon and plays an important role in the process of skin aging. However, the mechanism is unknown. Recent studies indicate the long-term stable existence of miRNAs in the cellular gaps and there’s a new signal transmission method involved in the occurrence of the diseases. Our previous study found that there’s a significant difference in.the expression of secretory miRNA in a skin photoaging model and multiple downstream target sites of some miRNAs ( such as miR-23a、miR-34a、miR-195 ) are involved in aging-related telomere pathway corresponding with the degree of skin aging in the non-radiated parts. Hence suggesting that secretory miRNA may mediate the skin aging bystander effect . On this basis, our present study plans to establish a skin aging model by using a high throughput sequencing system in order to comprehensively screen the secretory miRNAs related with the skin aging.bystander effect. Through in vitro cellular research and 3D skin culture system we would like to further validate the possible regulatory effects of secretory miRNA on skin aging pathway and would also like to investigate the underlying mechanism by which the secretory miRNA mediate skin aging bystander effect. With this study we expect to further clarify the occurrence and exacerbation of skin aging and provide new insights for the prevention and treatment of skin aging.

新近发现的皮肤老化旁观者效应是加剧机体老化的重要原因，但机制未明。研究表明分泌型miRNAs在细胞间隙中长期稳定存在，并可作为新型信号传递方式参与疾病的发生。我们的前期研究发现，皮肤光老化模型中分泌型miRNA表达显著差异，其中部分miRNAs（如miR-23a、miR-34a、miR-195等）的多个下游靶位点均被预测参与老化相关端粒途径，并与非辐射部位皮肤老化程度呈相关性，提示分泌型miRNA可能介导了皮肤老化的旁观者效应。本项目拟在此基础上，建立皮肤老化模型，通过高通量测序系统筛选与皮肤老化旁观者效应相关的分泌型miRNAs；通过体外细胞和三维皮肤模型进一步验证可能对皮肤老化通路存在调控作用的分泌型miRNA；并通过功能获得或缺失实验对分泌型miRNA介导皮肤老化旁观者效应的发生机制进行探讨。通过本研究的开展有望能进一步阐明皮肤老化的发生及其加重机制，为皮肤老化的防治提供新的靶点。

研究背景和主要研究内容.受辐射的皮肤成纤维细胞产生的囊泡作为新型的细胞间通讯工具参与紫外线照射诱导的旁观者效应，且这种功能与其包裹的分泌型miRNA密切相关。本课题旨在研究分泌型非长链RNA在紫外线旁观者效应中的作用，并进一步探索分泌型非长链RNA参与紫外线旁观者效应的分子机制。.结果：.1.紫外线辐射可诱导皮肤成纤维细胞生成微囊泡，并可以被受体细胞摄取，导致受体细胞的生长抑制，介导受体细胞的氧化损伤及凋亡。.2.急性中长波紫外线辐射旁观者效应中存在多种信号通路的激活，包括Rap1信号通路、FAK相关信号通路、MAPK信号通路等重要代谢通路。.3.急性中长波紫外线辐射可介导分泌型miRNA的表达，并通过微阵列及PCR法筛选出相应的分泌型miRNA，证明了miR-769-5p和miR-4655-3p在紫外线旁观者效应中的正调节。.4.证实了miR-769-5p和miR-4655-3p分别通过下游靶基因TGFBR1和E2F2发挥作用。.5.circRNA-100797靶向miR-23a-5p在紫外线辐射后细胞的抗衰老功能中发挥了作用。.结论：分泌型miR-769-5p和miR-4655-3p通过靶向其下游的基因在紫外线的旁观者效应中发挥了重要作用，为皮肤老化的防治提供了新的靶点。