雌激素受体α和β在水飞蓟宾对抗中波紫外线皮肤损伤中的作用研究

The flavonolignan silibinin was a commonly used hepatoprotective drug. In recent years, many new pharmacological roles of this old compound were found, including the anti-tumor, anti-diabetes and anti-neuron degeneration effects. Our previous researches have also found that silibinin protected the skin against ultraviolet B (UVB) injury both in vitro and in vivo, and the underlying mechanisms in epidermal and dermal cells or tissues were totally different. Based on the chemical structure, silibinin was supposed to have estrogen-like effects. Indeed, some studies showed the estrogen-like action of silibinin, however, this action was too complex to be elucidated clearly. Estrogen receptors were typically classified to a subtype of estrogen receptor α and another type of β (ERα and β), which had large differences in both function and distribution in cells. Besides the classical regulation of gene transcription in the nucleus, ERs were also found to directly act on the cell membrane and mitochondria, which had not been fully discussed. This subject was designed to study the cellular distribution of ERs on different locations, particularly the cellular nucleus, cell membrane and mitochondria and their different biological activity, and aimed to get the roles of ERs in the protection of silibinin against UVB damage on epidermal and dermal cells. The study would be done on the human immortalized keratinocytes HaCaT cells and human foreskin fibroblasts HFF cells simultaneously, and verified on murine epidermis and dermis. The results are promised to enrich the protective mechanisms of silibinin and the three different signalling pathways of ERs.

水飞蓟宾，一种黄酮木脂素类化合物，是临床常用的保肝药物。近年来发现它更多方面的药理学活性，如抗肿瘤、抗糖尿病和抗神经退化等。课题组前期体内外研究均发现水飞蓟宾具有抗皮肤UVB损伤的作用，且在表皮和真皮中存在机制上的明显差异。基于水飞蓟宾的结构，它被推测具有雌激素样作用。一些研究也证明了它的雌激素样作用，但极具复杂性，目前尚未研究清楚。雌激素受体主要包括ERα和β两种亚型，二者功能和分布上均有较大差异。ERs除了经典的入核调节基因转录这一作用外，现已发现均能在细胞膜和线粒体上发挥直接作用，但研究尚不充分。本课题将对细胞核、细胞膜和线粒体上的ERs分布以及功能进行考察，以获得ERs在水飞蓟宾抗表皮和真皮UVB损伤方面的作用。研究将在人永生化角质形成细胞HaCaT和人包皮成纤维HFF细胞中同时展开，并在小鼠表皮和真皮组织中验证。研究结果将充实水飞蓟宾的保护机制，同时完善ERs的三种信号通路。

水飞蓟宾，一种黄酮木脂素类化合物，是临床常用的保肝药物。近年来发现它具有抗皮肤UVB损伤的作用，且在表皮和真皮中存在机制上的明显差异。水飞蓟宾被推测具有雌激素样作用。雌激素受体（ER）主要包括ERα和β两种亚型，二者功能和分布上均有较大差异。本课题对ERs在水飞蓟宾抗表皮和真皮UVB损伤方面的作用进行考察。在人包皮成纤维HFF细胞中，水飞蓟宾抑制UVB诱导的细胞凋亡。有意思的是，水飞蓟宾增加UVB照射的细胞中ERα和ERβ的全细胞和核内蛋白水平。使用雌二醇激活ERα和ERβ可降低UVB诱导的细胞凋亡。ERα激动剂增强细胞的存活，而其拮抗剂降低细胞存活。ERβ激动剂也增加细胞存活。沉默ERα和ERβ削弱水飞蓟宾对于UVB处理的细胞的保护作用。在UVB处理过的人永生化角质形成细胞HaCaT中，ERα和ERβ都被水飞蓟宾的处理所增加。使用药理学抑制剂或者小干扰RNA抑制ERα或ERβ的水平都降低了UVB处理的HaCaT细胞的存活，无论是否有水飞蓟宾的存在。总的来说，水飞蓟宾在UVB照射的真皮HFF细胞和表皮HaCaT细胞中都通过增强ERα和ERβ通路而发挥保护作用。此外，UVB处理会诱导DNA的损伤和自细胞核的泄露，胞浆DNA感受器cGAS-STING蛋白通路在UVB处理的HaCaT细胞中的作用也被进行了研究。我们发现STING下游的NF-κB和IFNβ通路都介导了UVB所诱导的凋亡的发生。水飞蓟宾对cGAS-STING通路有抑制作用。水飞蓟宾还能抑制UVB处理的HaCaT细胞中YAP的核转位，从而通过抑制p73通路而产生抗凋亡作用。水飞蓟宾的雌激素样作用是否参与cGAS-STING和YAP通路的调节将在近期进行探讨。水飞蓟宾的雌激素样效应也贡献于对棕榈酸、胰淀素和Aβ1-42导致的胰岛β细胞损伤的保护作用。但水飞蓟宾对乳腺癌细胞具有杀伤作用，我们发现了它可通过一条ER依赖的AIF途径和另一条ER非依赖的线粒体破坏途径来诱导凋亡的发生。水飞蓟宾同样对乙醛诱导的肝细胞损伤具有保护作用，但不影响乙醇诱导的肝细胞损伤。这些结果都探索了水飞蓟宾的药理学作用特点，同时丰富了水飞蓟宾ER样作用可产生的药理学效应。