Suppression of AVIC inflammosteogenesis for prevention of CAVD progression

项目摘要 钙化性主动脉瓣病(CAVD)在老年人中很常见。CAVD进展为显著的主动脉狭窄 在大多数患者中会持续数年。这一懒惰的过程为治疗干预提供了机会 在早期阶段阻止疾病的发展。然而，对CAVD潜在机制的了解有限 进展阻碍了有效药物疗法的发展。在目前的资助期，我们的 广泛的研究已经确定了由先天免疫受体，特别是TLR2介导的信号机制 和TLR4，作为人主动脉瓣间质细胞(AVICs)成纤维和成骨活性的调节因子。 我们还发现，氧化型低密度脂蛋白(OxLDL)和细胞外基质(ECM)蛋白 2在人AVICs中作为损伤相关分子模式(DAMP)发挥作用，促进细胞分化 肝纤维化和成骨活性增强的激活。此外，我们观察到人类单核细胞 TLR2激活通过旁分泌上调促纤维化和促成骨介质的AVIC表达 机制。在这一更新应用中计划进行的研究将检验不同分子 中航工业先天免疫应答触发的机制促进细胞和瓣膜纤维化和成骨 通过诱导细胞激活和/或肌成纤维细胞转变而发挥活性。我们进一步假设- 调节中航工业先天免疫反应具有抑制瓣膜纤维化和改善心脏瓣膜功能的作用 钙化。这些假设是基于我们最近观察到的oxLDL升高中航工业纤维化和 成骨活性是通过肌成纤维细胞过渡非依赖性机制实现的，而可溶性Matrlin 2 通过诱导肌成纤维细胞转化，提高人血管内皮细胞的这些活性。此外，我们发现， 人类AVICs表达抗衰老蛋白Klotho。这种抗衰老蛋白能够调节AVIC 先天免疫反应。有趣的是，Klotho在主动脉瓣组织和AVICs中的水平要低得多。 患有CAVD和Klotho功能不全的患者会加剧瓣膜纤维化和成骨活动。这笔赠款 申请将涉及：(1)中航工业纤维生成和成骨活动的潜在机制，(2) Klotho不足加剧中航工业纤维化和成骨活性的机制，(3)抗 炎性途径上调Klotho在主动脉瓣中的表达以及(4) Klotho可缓解瓣膜纤维化和钙化。这项拟议的工作将提供对 CAVD进展的病理生物学及药物干预治疗靶点的确定 CAVD进展。

Project Summary Calcific aortic valve disease (CAVD) is common in the elderly. CAVD progression to significant aortic stenosis occurs over years in most patients. This indolent course affords the opportunity for therapeutic intervention to halt the disease progression at an early stage. However, limited knowledge of mechanisms underlying CAVD progression impedes the development of effective pharmacological therapies. In the current funding period, our extensive studies have identified signaling mechanisms mediated by innate immune receptors, particularly TLR2 and TLR4, as regulators of the fibrogenic and osteogenic activities in human aortic valve interstitial cells (AVICs). We also discovered that oxidized low-density lipoprotein (oxLDL) and extracellular matrix (ECM) protein matrilin 2 function as damage-associated molecular patterns (DAMPs) in human AVICs, prompting differential cell activation with elevated fibrogenic and osteogenic activities. In addition we observed that human monocytes activated by TLR2 up-regulate AVIC expression of pro-fibrogenic and pro-osteogenic mediators via a paracrine mechanism. Planned studies in this renewal application will test the central hypothesis that distinct molecular mechanisms triggered by AVIC innate immune response elevate cellular and valvular fibrogenic and osteogenic activities through induction of cell activation and/or myofibroblastic transition. We further hypothesize that down- regulation of AVIC innate immune response has therapeutic potential to suppress valvular fibrosis and calcification. These hypotheses are based on our recent observation that oxLDL elevates AVIC fibrogenic and osteogenic activities through a myofibroblast transition-independent mechanism, whereas soluble matrilin 2 elevates these activities in human AVICs through inducing myofibroblastic transition. Moreover, we discovered that human AVICs express anti-aging protein Klotho. This anti-aging protein is capable of modulating AVIC innate immune response. Interestingly, Klotho levels are much lower in aortic valve tissues and AVICs from patients with CAVD, and Klotho insufficiency exacerbates valvular fibrogenic and osteogenic activities. This grant application will address: (1) the mechanisms underlying AVIC fibrogenic and osteogenic activities, (2) the mechanism by which Klotho insufficiency exacerbates AVIC fibrogenic and osteogenic activities, (3) anti- inflammatory approaches to up-regulate Klotho expression in aortic valve and (4) the therapeutic potential of Klotho to alleviate valvular fibrosis and calcification. This proposed work will provide mechanistic insights into the pathobiology of CAVD progression and identify therapeutic targets for pharmacological intervention to halt CAVD progression.