NGF活化转录因子CREB促进绒山羊次级毛囊外根鞘细胞增殖的机制研究

Proliferation of hair Outer Root Shelther cells is one of the power of secondary air follicle growth and development, and to explore factors affecting ORS cells proliferation and its mechanism is important for Cashmere goats production. In our precious study, we firstly found that the expression of NGF mRNA was in a seasonal variation pattern in the skin of Liaoning cashmere goats, and NGF secretion from ORS cells of secondary hair follicles and NGF recombinant proteins promoted the proliferation of ORS cells by binding with it receptor TrkA on the membrane and caused CREB transcription factors activation. Therefore, there are two major questions: （1）how does the signal transduct in the upstream of CREB; （2）What are the target genes involved in the process of proliferation induced by NGF. To clarify the questions, Seap reporter system and flew cytometry were used to study whether the activation of CREB induced by NGF was dependent on the activation of MAPK or PI3K signaling pathway, then RNA-seq and Bioinformatics methods were used to explore mechanism of NGF-CREB-target genes involved in the process of ORS cells proliferation. This project will clarify the effect and mechanism of NGF on the development of Cashmere goat secondary hair follicles and give us new insights in cashmere production.

外根鞘细胞（ORSC）增殖是绒山羊次级毛囊细胞补充和生长的重要动力来源，但ORSC增殖的影响因素及作用机制仍不清楚。前期研究发现神经生长因子（NGF）在绒山羊绒毛生长期表达量显著高于静止期；次级毛囊ORSC可以表达NGF，且ORSC内转录因子CREB的活性和细胞增殖受NGF调控。据此，我们提出“NGF通过活化CREB调节相关基因表达的方式促进ORSC增殖”的假设。阐明该假设必须探明：（1）NGF-CREB之间信号是如何传递的；（2）CREB哪些靶基因参与NGF对ORSC的促增殖作用。本项目拟采用seap报告系统、流式细胞和蛋白印迹等技术研究MAPK和PI3K信号通路激活与NGF促进ORSC增殖和CREB活性变化的关系，探讨CREB的上游信号传递过程；利用DGE测序和生物信息学方法分析哪些CREB靶基因参与了NGF对 ORSC增殖的促进作用。结果将为阐明羊绒生长机制和提高产绒量提供新的思路。

外根鞘细胞(ORSC)增殖是绒山羊次级毛囊细胞补充和生长的重要动力来源，但ORSC增殖的影响因素及作用机制仍不清楚。前期研究发现神经生长因子（NGF）在绒山羊绒毛生长期表达量显著高于静止期；次级毛囊ORSC可以表达NGF，且ORSC内转录因子CREB的活性和细胞增殖受NGF调控。本项目在前期工作的基础上，研究 NGF活化 CREB的上游 MAPK 和 PI3K 信号通路的激活情况，再通过分别阻断信号通路后，结合 ORSC 增殖的变化结果，探讨 NGF 活化 ORSC 中 CREB 分子的上游信号传递过程；对于 NGF-CREB 下游事件，本课题在抑制 CREB 活性的基础上用NGF 或联合使用受体阻断剂处理次级毛囊 ORSC，利用数字基因表达谱(Digital Gene Expression Profiling, DGE)测序和生物信息学方法系统分析 CREB 下游哪些增殖相关基因参与了 NGF 对次级毛囊 ORSC 增殖的促进作用。本课题的研究成果将为阐明 NGF 促进次级毛囊 ORSC 增殖提供理论依据，期望为深入研究绒山羊毛囊发育机制和提高山羊绒产量提供新的思路。