SKPs通过介导转录因子Nrf2信号通路抗皮肤光损伤的作用研究

Skin photodamage exhibits poorly clinical efficacy, so far having rarely satisfactory treatments. It is considered that UV-induced ROS elevation, oxidative stress damage and Nrf2 inactivation play primary roles in the pathogenesis of skin photodamage, while Nrf2 is a crucial regulatory factor in the development of disease. So Nrf2 activation may be the important target against skin photodamage. It has been proved that stem cells can participate in tissue repair via activating Nrf2, while SKPs are predominant over the skin injuries repair and regeneration. The outcomes from our preliminary experiments revealed that SKPs had little variation in cell amount or morphous and possessed high expression of Nrf2 after ultraviolet irradiation. Thus, we assume that SKPs may have a therapeutic effect on skin photodamage by rejecting oxidative insult via activation of Nrf2 signaling pathway. Therefore, we will intend to culture SKPs in vitro and transplant them to photodamage animal models and three-dimensional skin modles, using techniques of histology and molecular biology to observe the changes of skin pathology and Nrf2, HO-1, and etc. levels before and after cell transplantation. Meanwhile, Nrf2 signaling pathway will be studied through modifying Nrf2 gene on SKPs by gene over-expression/ silence and transfection methods to study This will elucidate the therapeutical effect and mechanism of SKPs on skin photodamage and provide an experimental basis for SKPs treating skin photodamage.

皮肤光损伤临床疗效较差，至今无满意疗法。其病机主要与UV诱导的活性氧升高、氧化应激损伤和转录因子Nrf2信号失活有关，而Nrf2在此发病中起关键的调控作用，故激活Nrf2可能是抗光损伤的重要靶点。研究表明干细胞可通过激活Nrf2参与组织修复，真皮干细胞SKPs对皮肤损伤修复和再生具有显著的优势。我们前期实验发现SKPs经UV照射后细胞数无减少、形态无变异，Nrf2表达水平升高。因此我们设想SKPs可通过高表达Nrf2激活其通路，阻止氧化应激损伤，从而在抗皮肤光损伤中起作用。故本课题拟体外培养SKPs移植到光损伤动物模型和三维皮肤模型，结合组织学和分子生物学方法观察移植前后皮肤病理改变和Nrf2、HO-1等变化。应用基因表达、沉默及转染技术对SKPs的Nrf2信号通路进行特异性过表达或抑制研究。本项目将阐明SKPs对皮肤光损伤的治疗作用及机制，为研究SKPs抗皮肤光损伤提供实验依据。

皮肤光损伤疗效差且无满意疗法，其发病主要与UV诱导过多活性氧、氧化应激损伤和Nrf2信号失活有关，其中Nrf2起着关键的调控作用，因此激活Nrf2是抗光损伤的重要靶点。干细胞通过激活Nrf2能促进组织修复，而真皮干细胞SKPs在皮肤损伤修复中具有显著的优势。我们前期研究发现SKPs经UV照射后高表达Nrf2。故SKPs通过高表达Nrf2可激活其通路，阻止氧化应激损伤，从而抗皮肤光损伤。因此本课题通过体外培养SKPs移植到光损伤动物模型以及将Nrf2基因修饰后的SKPs移植到三维皮肤模型，应用系列组织学、分子生物学方法观察移植前后皮肤病理改变和Nrf2及其信号通路等变化。结果发现：SKPs移植到光损伤模型鼠后在鼠皮内存活良好，能显著改善光损伤鼠皮肤外观，明显减轻角质层角化、棘层肥厚等组织病理学表现（基本接近正常鼠），同时使凋亡细胞数明显减少，Nrf2、HO-1、SOD等表达升高，MDA和H2O2水平降低，初步表明SKPs具有抗皮肤光损伤作用，可能通过激活Nrf2/HO-1通路抗氧化应激损伤而作用的；为进一步阐明SKPs抗氧化应激损伤的作用机制，我们将过表达和沉默Nrf2的SKP移植分别到体外三维皮肤光损伤模型中，发现过表达Nrf2的SKP能明显减少UV诱导的细胞凋亡和改善光损伤三维皮肤病理组织学改变，同时上调细胞内保护基因和Nrf2/HO-1/PI3K/Akt的表达，促进MDA、SOD等氧化/抗氧化系统平衡，而沉默了Nrf2的SKPs则对光损伤三维皮肤模型无明显改善。证实SKPs是通过激活Nrf2及Nrf2/HO-1/PI3K/Akt 通路和抑制氧化应激损伤进而抗皮肤光损伤。本项目初步阐明了SKPs对实验性皮肤光损伤具有较好的治疗作用，为SKPs抗皮肤光损伤应用临床提供实验依据。