衰老MSC通过MMP1/PAR1信号调控MDS克隆细胞增殖的机制研究

Cellular senescence participated in tumorigenesis by secreting protease, inflammatory factors, which changed the microenvironment. The role of abnormal cellular senescence of MSC in MDS is not clear. In previous studies, we found that MSC senescence was increased in MDS patients. Senescent MDS - MSC expressed higher MMP1 than controls and MDS CD34 + cells expressed higher PAR1, which is the receptor of MMP1. After co-culture with senescent MDS–MSC, MDS-CD34 exhibited increased cell proliferation, and PAR1 inhibitor can block this effect. We infer that MSC dependent MMP1 / PAR1 signals is a tumorigenesis signal, which play a positive role in promoting proliferation of MDS cloned cell. To test this hypothesis, we will employ MDS cell lines, primary cell and mouse model to reveal the role of MSC senescence in MDS and clarify the molecular mechanism of cell proliferation induced by MMP1/PAR1 signal, using the WB, FCM, adenovirus transfection, RNA interference, CHIP, et al. We will provide empirical evidence from the molecules, cells and animal levels. This study will lay the foundation for the pathogenesis of MDS from the microenvironment senescence, a new viewpoint, and provide new ideas for MDS treatment in the aspect of microenvironment.

细胞衰老可通过分泌蛋白酶、炎性因子等改变微环境，参与肿瘤的发生。MDS-MSC异常衰老如何参与疾病的发生发展尚不清楚。在前期工作中我们发现：MDS骨髓微环境中MSC衰老增加；衰老的MDS-MSC高表达MMP1，而MDS CD34+细胞高表达MMP1受体PAR1；衰老MDS-MSC与MDS细胞共培养后明显诱导细胞增殖，而PAR1抑制剂可阻断该效应。申请人推测MSC依赖的MMP1/PAR1信号是一个原癌信号，该信号的激活有助于MDS克隆细胞增殖。为验证这一假说，我们将通过MDS细胞系、原代细胞及小鼠模型，采用WB、FCM、腺病毒转染、RNA干扰、CHIP等手段，从分子、细胞及动物水平探讨MSC衰老在MDS克隆细胞增殖中的重要作用，明确其诱导的MMP1/PAR1信号调控MDS克隆细细胞增殖的分子机制。本研究将从微环境衰老这个新视点为揭示MDS发病机制奠定基础，为MDS治疗在微环境方面提供新思路。

MDS独特的骨髓微环境信号是MDS克隆细胞生长所必需的。MDS-MSCs如何参与疾病的发生发展尚不清楚。通过本项目我们发现MDS-MSCs成脂分化能力普遍减弱，低危患者成骨能力下降，而高危患者成软骨能力减弱，MDS-MSCs中衰老细胞比例增加。MDS-MSCs对MDS细胞的增殖抑制作用较正常MSCs明显减弱。MMP1在MDS患者的MSCs中表达较正常人MSCs降低，且高危患者较低危患者表达更低。在共培养试验中，MMP1-KD-MSC组MDS细胞S期比例增加，而凋亡细胞比例减少。外源性MMP1所引起的MDS细胞增殖减弱和凋亡增加可被PAR1拮抗剂所阻断。进一步研究显示MMP1是通过激活PAR1-p38 MAPK通路影响MDS细胞的增殖和凋亡。本课题相关研究成果将有助于深入理解骨髓微环境在MDS发生发展中的作用，探索其分子机制及可能的靶向干预作用，为MDS骨髓微环境治疗靶点提供一种新思路。