Sphingolipids and their Impact in Corneal Wound Healing

鞘脂及其对角膜伤口愈合的影响

• 批准号: 10298908
• 负责人: Dimitrios Karamichos
• 金额: $ 6.15万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2021-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10298908
• 关键词: 3-Dimensional; Affect; Animals; Area; Attention; Blindness; Cell Culture Techniques; Ceramides; Cicatrix; Clinical Management; Complex; Cornea; Corneal Diseases; Corneal Injury; Corneal Opacity; Corneal dystrophy; Data; Development; Disease; Economics; Enzymes; Extracellular Matrix; Feedback; Fibroblasts; Fibrosis; Future; G-Protein-Coupled Receptors; GTP-Binding Protein alpha Subunits, Gs; Genetic Transcription; Growth Factor; Human; In Vitro; Infection; Injury; Investigation; Keratoconus; Keratoplasty; Knock-out; Knockout Mice; Knowledge; Liver Fibrosis; Mediating; Mediator of activation protein; Metabolism; Modeling; Mus; Myofibroblast; Operative Surgical Procedures; Outcome; Pathologic; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Process; Protein Isoforms; Pulmonary Fibrosis; Research; Role; SPHK1 enzyme; Signal Pathway; Signal Transduction; Signaling Protein; Site; Sphingolipids; Sphingosine-1-Phosphate Receptor; Stromal Cells; Testing; Therapeutic; Tissues; Transcriptional Activation; Transforming Growth Factor beta Receptors; Transforming Growth Factors; Trauma; United States National Institutes of Health; Up-Regulation; Visual Acuity; Wild Type Mouse; base; chemokine; clinically significant; corneal epithelial wound healing; corneal scar; coronary fibrosis; cytokine; design; effective therapy; experimental study; fibrogenesis; human disease; human model; in vitro Model; in vivo; in vivo Model; inhibitor/antagonist; migration; new therapeutic target; novel; prevent; receptor; response; small molecule inhibitor; sphingosine 1-phosphate; therapeutic development; therapeutic evaluation; three-dimensional modeling; treatment strategy; wound healing

Up to one fourth of all cases of blindness worldwide are attributable to corneal opacities generated by scarring, or fibrosis, representing a huge economic and societal burden. No effective therapies for corneal fibrosis have been developed and the most reliable treatment option is corneal transplantation, which has numerous limitations/ and complications, including post-surgical corneal fibrosis. Corneal fibrosis is characterized by the formation of corneal scars from over-accumulation of disorganized extracellular matrix (ECM) produced by fibroblasts and myofibroblasts after they are activated by injury or infection. The corneal wound-healing, as well as the process of fibrosis, is driven by multiple complex pathways involving many cytokines, growth factors, and chemokines, which are not completely understood. The lack of knowledge regarding this process is a critical barrier to developing new treatment strategies to minimize scarring and retain or restore corneal transparency. Our recent advances, with the aid of an NIH/NEI R21 (EY025256), have led us to discover a novel potential mechanism that combines sphingolipid (SPL) signaling with classical transforming growth factor-β (TGF-β) pathways to mediate corneal fibrosis via activation/differentiation of keratocytes into myofibroblasts. We have also demonstrated that SPL metabolism is altered in “injured” corneal stromal cells, and that stimulation of healthy corneal stromal cells with Sphingosine 1-Phosphate (S1P), a bioactive SPL, induces TGF-β1 expression and fibrosis, signaling through the S1P receptor 3 (S1P3). Furthermore, we found that TGF-β isoforms can increase S1P3 signaling by increasing expression of Sphingosine kinase 1 (SPHK1; an enzyme that synthesizes S1P) and S1P3. Based on these discoveries, we hypothesize that S1P is a key mediator of corneal fibrosis via activation of TGF-β, and TGF-β in turn induces expression of S1P signaling proteins and thus forms a positive feedback loop which drives irreversible activation of corneal fibroblasts and differentiation to myofibroblasts. The proposed studies are designed to clearly define the key players in these pathways and delineate how they interact in the context of corneal fibrosis using our in vitro 2D and 3D models of human and mouse corneal stromal cells (Aim 1); and in vivo models of corneal wound healing in wild type, Sphk1, and S1P3 knockout mice, along with testing the therapeutic potential of targeting S1P and TGF-β signaling using selective inhibitors in these models (Aim 2). The role of S1P in corneal fibrosis has not received substantial attention and we are currently the only group pursuing SPL-based processes as part of the potential mechanism. If successful, the results from the proposed studies could have far-reaching scientific and clinical significance, as the understanding of corneal fibrotic mechanisms and the role of S1P as an important mediator would not only be important for clinical management/treatment of corneal fibrosis, but could also be applicable to many diseases in which fibrosis is a major pathological outcome, such as liver, lung, and cardiac fibrosis.

全世界最多有四分之一的盲目病例归因于角膜骨骼。 疤痕或纤维化，代表了巨大的经济和社会负担。没有有效的角膜疗法 已经开发了纤维化，最可靠的治疗选择是角膜移植， 许多局限性/并发症，包括手术后角膜纤维化。角膜纤维化是 以过度累积的细胞外基质形成角膜疤痕的特征 （ECM）由成纤维细胞和肌纤维细胞通过损伤或感染激活后产生。角膜 伤口治疗以及纤维化过程，由许多涉及许多复合途径驱动 细胞因子，生长因子和趋化因子尚未完全了解。缺乏知识 关于此过程，是制定新的治疗策略以最大程度地减少疤痕和保留的关键障碍 或恢复角膜透明度。我们最近的进步借助NIH/NEI R21（EY025256）带领我们 发现一种新型的潜在机制，该机制将鞘脂（SPL）信号与经典转换相结合 生长因子-β（TGF-β）途径通过激活/分化角膜细胞向角膜纤维化进行介导 肌纤维细胞。我们还证明了SPL代谢在“受伤的”角膜基质细胞中发生了改变， 并用1-磷酸盐（S1P）刺激健康的角膜基质细胞，一种生物活性SPL， 通过S1P受体3（S13）诱导TGF-β1表达和纤维化。此外，我们发现 TGF-β同工型可以通过增加鞘氨酸激酶1的表达来增加S13信号传导（SPHK1； A 合成S1P）和S13的酶。基于这些发现，我们假设S1P是关键 角膜纤维化介质通过激活TGF-β，而TGF-β反过来诱导S1P信号的表达 蛋白质，因此形成一个正反馈回路，可驱动角膜成纤维细胞的不可逆转激活和 与肌纤维细胞的区分。拟议的研究旨在清楚地定义这些主要参与者 途径并描绘了它们在角膜纤维化的背景下使用我们的体外2D和3D模型的相互作用 人和小鼠角膜基质细胞的; AIM 1）;以及野生类型的角膜伤口愈合的体内模型， SPHK1和S13基因敲除小鼠，并测试靶向S1P和TGF-β的治疗潜力 在这些模型中使用选择性抑制剂的信号传导（AIM 2）。 S1P在角膜纤维化中的作用尚未接受 广泛的关注，我们目前是唯一一个追求基于SPL的流程作为潜力一部分的小组 机制。如果成功，拟议的研究的结果可能具有深远的科学和临床状态 意义，作为对角膜纤维化机制的理解和S1P作为重要介体的作用 不仅对于角膜纤维化的临床管理/治疗很重要，而且还适用 对于许多纤维化是主要病理结果的疾病，例如肝脏，肺和心脏纤维化。