TNF-α通过GCN5介导的表观遗传修饰导致喉黏膜间充质干细胞功能异常的机制研究

慢性喉炎难以治愈是由于炎症导致的局部组织稳态破坏。本项目组证明喉黏膜间充质干细胞（LMSCs）通过自我更新、多向分化及免疫调控维持局部稳态平衡，与喉炎发生发展密切相关。同时发现TNF-α长期刺激导致MSCs功能不可逆的改变，提示其是喉炎迁延不愈的原因，但机制不清。慢性炎症可导致干细胞表观修饰异常，本项目组发现炎症LMSCs中组蛋白乙酰化水平改变，而TNF-α可影响乙酰转移酶GCN5的表达，推测GCN5介导的表观遗传学改变导致了炎症LMSCs功能持续下降。依此本项目拟明确正常与炎症组织LMSCs中GCN5及其修饰位点表达差异，利用GCN5慢病毒过表达/干扰技术明确其对于细胞的作用，利用CHIP-chip技术明确GCN5调控基因靶点，探讨TNF-α调控GCN5的信号调控机制，建立大动物喉炎体内治疗模型，为深入探索MSCs在炎症发生中的作用、表观遗传与疾病发生、慢性炎症治疗新策略提供实验依据

Refractory of chronic laryngitis is due to the disturbance of homeostasis. Our research group have proved that laryngeal mesenchymal stem cells (LMSCs) resided in laryngeal mucosa play importance role in tissue homeostasis. We found that long-term stimulation of inflammatory factors such as TNF-α induced persistent changes of proliferation and differentiation of MSCs, suggesting it is an important factor of recurrence of chronic laryngitis. However, the mechanism remains elusive. Chronic inflammation could cause abnormal epigenetic modification. We found that the levels of histone acetylation were abnormal in LMSCs derived from inflammatory laryngeal tissue. Moreover, TNF-α could significantly affect the expression of GCN5, an important acetyltransferase, suggesting that GCN5-mediated epigenetic modification leads to permanent dysfunction of LMSCs during chronic laryngitis. Therefore, our project is subjected to determine the levels of key modification of histone acetylation and expression of GCN5 complex, to investigate the function of GCN5 on MSCs differentiation and self-renew based on siRNA and lenti-virus techniques, to explore the key target genes regulated by GCN5 by CHIP-chip analysis, confirm the molecular mechanism that TNF-α regulating GCN5, and establish large-animal laryngitis treatment model. Our study is aimed to get further understanding of interaction between inflammatory niche and stem cell, explore specific epigenetic modification that regulating MSCs function, and provide basic experimental evidence for novel strategy for treatment of chronic inflammatory diseases.