Sox基因调控Wnt/β-catenin信号通路抑制胰腺星状细胞的活化及逆转胰腺纤维化的机制研究

Chronic pancreatitis (CP) is characterized by progessive pancreatic fibrosis. It was well established that the persistent activation of panreatic stellatec cells (PSCs) plays a pivotaol role in the pancreatic fibrogenesis, while the differentiation and outcome of activated PSC determines the pathological outcome after pancratic injury. Previously, we found that Sox genes family were markedly doewnregulated during pancratic fibrogenesis, while β-catenin was upregulated. Furthermore, Dkk (inhibitor of Wnt signaling pathway) can inhibit the activation and proliferation of PSC in vitro by downregulating β-catenin expression.Thus we speculate that in the CP process, Sox genes in the quiescence of PSC from the autocrine inhibition of Wnt/β-catenin signaling pathway is blocked, leading to dynamic imbalance of PSC activation and differentiation and outcome, thereby causing the pancreas fibrosis. The purpose of this study is to investigate the potential effects of Sox genes on the activation and outcome of PSCs through both in vitro and in vivo experiments, thereby clarifying the molecular mechanism of Sox genes and Wnt/β-catenin signaling pathway in the pancreatic fibrogenesis. Specifically, we propose to conduct the followying works: 1) Using in vitro cell-based systems, to observe the changes in the expression of Sox genes and Wnt signaling molecules and to determine its relationship with pancreatic fibrosis; 2) On the animal level, to investigate the effects of Sox genes on PSC activation, differentiation and outcome; 3) To investigate the effects of Sox genes on the Wnt/β-catenin signaling pathway,to clarify the Sox and Wnt/β-catenin to regulate the molecular mechanisms of panreatic fibrosis. These results will help unravel the molecular pathogenesis of mechanism of CP and may provide insight into the development of novel therapeutic agent for CP.

慢性胰腺炎（CP）以胰腺纤维化为主要病理特征，而胰腺星状细胞（PSC）持续活化是胰腺纤维化的核心机制，PSC的分化和转归决定了胰腺损伤后的病理结局。我们前期发现，在PSC的活化过程中存在Sox基因家族的下调和β-catenin的上调，同时发现Wnt抑制物能在体外抑制PSC的β-catenin的表达，从而抑制PSC的活化进程。因此，我们推测在CP的发生过程中，Sox基因存在抑制，使Wnt信号通路中的β-catenin异常激活，导致PSC活化和分化、转归的动态失衡，进而引起胰腺纤维化。本研究拟：1)建立细胞培养为主的体外模型，运用分子细胞生物学方法，观察Sox基因家族和Wnt信号分子的表达变化，确定其与胰腺纤维化的关系；2)观察Sox基因对于PSC活化和转归以及胰腺纤维化的影响；3)研究Sox基因对Wnt/β-catenin信号通路的影响，及其调节胰腺纤维化的分子机制，并探讨其潜在的临床价值。

慢性胰腺炎（CP）以胰腺纤维化为主要病理特征，而胰腺星状细胞（PSC）持续活化是胰腺纤维化的核心机制，PSC的分化和转归决定了胰腺损伤后的病理结局。我们前期发现，在PSC的活化过程中存在Sox基因家族的表达改变和β-catenin的上调，同时发现Wnt抑制物能在体外抑制PSC的β-catenin的表达，从而抑制PSC的活化进程。因此，我们推测在CP的发生过程中，Sox基因存在抑制，使Wnt信号通路中的β-catenin异常激活，导致PSC活化和分化、转归的动态失衡，进而引起胰腺纤维化。本研究通过体内外研究发现以下结果：1)通过体内慢性胰腺炎的模型检查，观察Sox基因家族的基因表达变化（Sox2、Sox11等表达下调，而Sox9表达上调），同时和Wnt信号分子及β-catenin的表达变化，同时通过免疫荧光定位，发现了在胰腺纤维化的组织中，胰腺间质内及胰腺星状细胞中存在的Sox9和β-catenin的表达上调；2)应用维甲酸干预慢性胰腺炎模型，发现维甲酸可以通过降低促炎因子的表达来减轻 CP 的胰腺损伤；能通过下调促纤维化因子的表达来减慢胰腺纤维化的发展进程，能通过下调Wnt 2、β-catenin及上调Axin2 的表达和降低 β-catenin 的核转位来抑制 Wnt/β-catenin 信号通路，从而减少 PSC 的活化数量；3)PSC的Wnt2和β-catenin的蛋白表达水平明显下调，而 Axin2的表达水平上调，同时RA抑制了β-catenin在PSC细胞中的核转位。除此之外，RA能明显抑制PSC的增殖和促进 PSC的凋亡，且能通过下调β-catenin、TGFβRII、PDGFR和collagen1α1 的mRNA的表达来抑制细胞外基质的生成。说明RA能够通过调控Wnt/β-catenin信号通路来抑制胰腺星状细胞（PSC）的活化。4)研究Sox9调控β-catenin的表达从而影响PSC的活化过程，通过SiRNA干扰PSC的Sox9表达，可相应影响抑制β-catenin的表达，从而抑制PSC的活化。我们的研究结果揭示了去Sox9及β-catenin调控的胰腺星状细胞的活化及在胰腺纤维化中的作用及其相关的分子机制，为抑制慢性胰腺炎进展的治疗手段提供了理论依据，同时为后续慢性胰腺炎及胰腺纤维化的研究开辟了新的领域。