Hydrogels to Study Synergistic Effects of Signaling Factors and Matrix Mechanics on Valve Disease Progression

肌成纤维细胞激活的瓣膜间质细胞(VICS)被认为是一个主要的驱动因素 瓣膜纤维化和狭窄。因此，起控制作用的外部线索 VICS的肌成纤维细胞表型一直是该领域研究的热点。 越来越多的证据表明，Beyond受体介导的VICS通过可溶性生长激活 在这一过程中，来自矩阵的因素和物理线索起着关键作用。不幸的是，传统的 用来培养VIC的方法本身就会导致它们的肌成纤维细胞激活，从而使其 很难确定环境僵硬对激活的影响，尤其是 停用。为了解决这个问题，我们团队展示了独特的水凝胶材料 可用于为VIC培养创建软的、非激活的底物，使VIC保持 表型更接近于新分离的细胞。现在，我们的目标是研究如何 基质僵硬和促炎细胞因子联合影响VIC成纤维细胞到血管内皮细胞 肌成纤维细胞的转变，这些细胞随着时间的推移可能发生的表观遗传变化，以及 可能有助于逆转致病肌成纤维细胞的基质信号通路 表型。具体地说，我们建议：1)使用组合方法来研究 促炎症细胞因子在VIC表型上作为微环境僵硬的函数2 确定机械和炎症信号对成纤维细胞到肌成纤维细胞的影响 利用具有动态可调机械性能的水凝胶进行相变及其逆转，以及3) 为治疗药物发现新的分子靶点以缓和病理性VIC肌成纤维细胞 炎症条件下的激活。共同完成这些目标中的每一个目标的工作 将为纤维性主动脉瓣狭窄的进展提供独特的洞察力。创造了一个 可调节的细胞培养平台将允许我们回答关于 可逆(瞬时，伤口愈合状态)和不可逆(持续，致病状态)VIC 传统方法不能充分处理的肌成纤维细胞。后续 对信号通路和基因的分析将被用来识别新的治疗靶点 有可能逆转VIC的激活和治疗瓣膜疾病。此外，成功完成了 这些目标应该引起医学领域的普遍关注，就像纤维化的机制一样 可能在大多数与纤维化相关的疾病中都是如此。

Myofibroblast activation of Valvular Interstitial Cells (VICs) is considered to be a primary driver of valvular fibrosis and stenosis. For this reason, the external cues that act to control the myofibroblast phenotype of VICs have been topics of considerable attention in the field. Increasing evidence suggests that beyond receptor-mediated activation of VICs by soluble growth factors, physical cues from the matrix play a critical role in this process. Unfortunately, traditional methods used to culture VICs inherently leads to their myofibroblast activation, such that it becomes difficult to determine the effects of environmental stiffness on activation and especially de-activation. To address this issue, our group has demonstrated that unique hydrogel materials can be used to create soft, non-activating substrates for VIC culture that allow VICs to maintain a phenotype that more closely resembles that of freshly isolated cells. Now, we aim to examine how matrix stiffness in combination with pro-inflammatory cytokines influence the VIC fibroblast-to- myofibroblast transition, the epigenetic changes that may occur to these cells over time, and the pathways in matrix signaling that might be useful in reversing the pathogenic myofibroblast phenotype. Specifically, we propose to: 1) Use a combinatorial approach to study the effect of pro-inflammatory cytokines on VIC phenotypes as a function of microenvironmental stiffness 2) Identify the effects of mechanical and inflammatory cues on the fibroblast-to-myofibroblast transition and its reversal using hydrogels with dynamically tunable mechanical properties, and 3) Discover new molecular targets for therapeutics to temper pathogenic VIC myofibroblast activation under inflammatory conditions. Together, work completed within each of these Aims will provide unique insight into the progression of fibrotic aortic valvular stenosis. The creation of tunable cell culture platforms will allow us to answer questions about differences between reversible (transient, wound healing state) and irreversible (persistent, pathogenic state) VIC myofibroblasts that cannot be adequately addressed with traditional methods. Subsequent analysis of the signaling pathways and genes will be used to identify new targets with therapeutic potential to reverse VIC activation and treat valve disease. Moreover, successful completion of these Aims should be of general interest to the field of medicine, as mechanisms of fibrosis are likely shared among most fibrosis-related diseases.