丹参酚酸B调控DNMT1促进前脂肪细胞成脂分化的作用机制研究

Fat transplantation is a new method for repairing soft tissue defects. How to improve the survival rate of transplanted adipose tissue is the current focusing point at present. There is a close relationship between the conversion of preadipocytes into adipocytes and the survival rate of transplanted fat tissue. DNA methyltransferase (DNMT) plays an important role in the differentiation of preadipocytes by performing DNA epigenetic modification. Studies have shown that DNMT1 can maintain DNA methylation in preadipocytes, maintain the stem cell characteristics of preadipocytes, DNMT1 silence led to accelerated adipocyte differentiation. At the same time, it has been reported that Salvianolic acid B can inhibit the expression of DNMT1, leading to DNA demethylation (J Cell Mol Med 2015). In the previous study, it was found that the induction of adipocyte differentiation was significantly increased in the presence of Salvianolic Acid B, which could significantly increase the survival rate of fat transplantation. Based on this, The project team proposed a hypothesis that Salvianolic Acid B inhibits DNA methylation by silencing DNMT1, which promotes the differentiation of preadipocytes into adipocytes. This project is proposed by the means of RNA interference technology, chip biological analysis and DNA methylation researching to study the effect of Salvianolic Acid B on regulating DNMT on adipogenic differentiation and its mechanism, in order to provide new thought on the improvement of fat transplantation survival rate.

脂肪移植是一种新兴软组织缺损修复方法，如何提高移植脂肪组织成活率是目前的焦点问题。前脂肪细胞成脂分化与提高移植脂肪存活率有密切关系。DNA甲基转移酶（DNMT）执行DNA表观遗传修饰，在前脂肪细胞分化过程中扮演关键角色。有研究表明，前脂肪细胞中DNMT1能维持DNA甲基化，维持前脂肪细胞的干性，DNMT1静默导致脂肪细胞分化加速。同时有报道，丹参酚酸B可抑制DNMT1的表达，导致DNA去甲基化【J Cell Mol Med 2015】。项目组前期研究发现，前脂肪细胞在丹参酚酸B干预下，成脂诱导分化明显增加，显著提高脂肪移植成活率。据此提出假说：丹参酚酸B通过静默DNMT1，抑制成脂相关基因的DNA甲基化，促使前脂肪细胞向脂肪细胞分化。本项目拟通过RNA干扰技术，芯片生物学分析和DNA甲基化研究等手段，研究丹参酚酸B调控DNMT1对成脂分化的影响及作用机制，为提高脂肪移植存活率提供新思路。

脂肪移植是一种新兴软组织缺损修复方法，如何提高移植脂肪组织成活率是目前的焦点问题。前脂肪细胞成脂分化与提高移植脂肪存活率有密切关系。DNA甲基转移酶（DNMT）执行DNA表观遗传修饰，在前脂肪细胞分化过程中扮演关键角色。有研究表明，前脂肪细胞中DNMT1能维持DNA甲基化，维持前脂肪细胞的干性，DNMT1静默导致脂肪细胞分化加速。.项目组前期研究，通过体外实验发现丹参注射液可以显著促进前脂肪细胞成脂分化，并将此研究成果应用于临床，发现丹参注射液可以显著提高自体脂肪移植保留率。进一步项目组将研究聚焦于丹参中含量最高，活性最强的水溶性成分丹参酚酸B，通过筛选获得丹参酚酸B的最佳有效浓度，甄别不同浓度其对前脂肪细胞的影响。在体内以及体外实验证明，丹参酚酸B能促进前脂肪细胞的分化和增值。其机制在于丹参酚酸B可以激活PPAR信号通路以及抑制ECM相关信号通路，从而促进前脂肪细胞成脂分化。通过分子对接模拟实验揭示了丹参酚酸B和DNMT1通过潜在的靶点，抑制DNMT1催化活性中心，从而抑制其活性。体内实验进一步证明了丹参酚酸B可以提高裸鼠皮下移植脂肪的存活率。综上所述，本项目的研究结果首次发现了丹参酚酸B可以通过抑制DNMT1催化活性中心，激活PPAR信号通路，抑制ECM相关通路，从而促进前脂肪细胞增殖分化从而提高移植脂肪的存活率。.在前脂肪细胞成脂分化中，本项目引入丹参酚酸B作为促进成脂分化的关键因素点，将表观基因学理论、中医药和整形外科组织移植理论相结合，突破学科界限，融合不同学术理论，为提高自体脂肪移植存活率提供了新的治疗手段及理论基础。