如何抑制基质金属蛋白酶（MMPs）过高表达、减轻光老化损伤是目前国内外研究热点。申请人前期发现纯化后的羊栖菜甘露聚糖能显著增强MMPs抑制活性，但其结构基础和作用机制尚不明确。TGF-β/Samd信号通路是调控MMPs的重要通路，但由于其他功能因子对其靶向调控作用不强而鲜被关注，这严重限制了光老化理论研究。前期发现甘露聚糖可靶向调控该通路个别靶点，但对其他靶点的调控作用尚不明确。因此，本项目将运用液质联用色谱和二维核磁共振波谱探讨羊栖菜甘露聚糖的结构对MMPs抑制活性的影响规律，揭示其结构基础，阐明其构效关系。并通过HaCaT细胞模型，采用qRT-PCR、western-blot和CRISPR/Cas9基因敲除技术系统研究其对TGF-β/Samd信号通路上关键靶点的调控作用，再通过动物模型验证该通路，阐明甘露聚糖靶向抑制基质金属蛋白酶的作用机制，为海洋生物活性多糖抗光老化理论研究奠定基础。

It has become research hotspot that how to inhibit the high expression of matrix metalloproteinases (MMPs) and reduce photoaging damage. The applicants have previously found that mannan purified from Sargassum fusiforme could significantly inhibit the production of matrix metalloproteinases. But its structure characteristic and related mechanisms are remain unknown. TGF-β/Samd signal pathway is an important pathway to regulate the expression of MMPs. But it lacks of study since other functional components don’t have the targeting regulation effect on it, which will badly delay the photo-aging theoretical study. Mannan could targeting regulate some target spots of this pathway based on our previous resutls. However, it is still unknown whether it could regulate other spots on the same pathway. Therefore, the project will further focus on how the structures of the mannan influence the MMPs inhibition activity, clarify their structure characteristic and structure-activity relationship by using high performance liquid chromatography-mass spectroscopy and two dimensional NMR spectroscopy. Then the important target spots on TGF-β/Samd pathway will be studied by using qRT-PCR, western-blot and CRISPR/Cas9 gene knockout technologies based on HaCaT cell model. The regulation effects on the above target spots will be further verified by animal model. It will clarify the mechanisms of mannan’s MMPs inhibition activity. The results will provide theoretical foundation for the research on marine polysaccharides with anti-photoaging activity.