Mechanistic study and therapeutic development for subretinal fibrosis

项目摘要 视网膜下纤维化是几种视网膜疾病的终末期发病机制的基础， 相关性黄斑变性（AMD）和增殖性玻璃体视网膜病变（PVR）。纤维化结果 并且是伤口愈合反应的一部分，其特征在于 细胞外基质（ECM）过度积聚形成结缔组织。 视网膜下纤维化可产生收缩力，引起瘢痕形成，大量视网膜下 出血和视网膜脱离，因此破坏视网膜结构并最终导致 到法律的盲目。视网膜下纤维化的细胞和分子机制尚不清楚， 这种情况的临床治疗非常有限。肌成纤维细胞是主要的细胞类型， 与纤维化密切相关肌成纤维细胞的细胞贡献是多样的， 异质性，涉及多种细胞类型。例如，RPE细胞有助于纤维化 通过上皮-间质转化（EMT），内皮细胞通过以下途径促进纤维化： 内皮-间质转化（endMT），巨噬细胞通过 巨噬细胞-间充质转化（MMT）。为了充分了解视网膜下的机制， 纤维化、肌成纤维细胞的作用以及不同细胞类型对视网膜下纤维化的贡献 需要解决。微小RNA（miRNAs或miRs）是内源性小分子，其可以 调节不同细胞类型中的不同途径。几种miRNA，包括miR-29、miR-24和 miR-21与纤维化相关。我们的初步数据显示，miR-24 过表达通过调节TGF-β/SMAD 3和LIMK 2/MRTF抑制EMT、endMT和纤维化 这表明miR-24可以作为视网膜下纤维化的理想治疗靶点， 针对不同细胞类型中的两个主要途径。这项提案的主要目标是阐明 肌成纤维细胞在视网膜下纤维化中的细胞贡献、身份和功能，并测试 miR-24在视网膜下纤维化中的治疗潜力。我们假设：（1）肌成纤维细胞 来自多个细胞谱系的miR-24可能导致视网膜下纤维化;以及（2）miR-24，可以抑制 因此，通过调节TGF-β/SMAD 3和LIMK 2/MRTF通路， 代表用于治疗AMD中视网膜下纤维化的优异的“一种药物/多个靶点”模型 的PVR。将追求两个目标：目标一是定义的功能，身份和起源， 视网膜下纤维化中的肌成纤维细胞;目的II是确定治疗潜力 miR-24在视网膜下纤维化中的作用拟议项目的成功完成将为 探讨AMD和PVR视网膜下纤维化的机制和治疗方法 患者

PROJECT SUMMARY Subretinal fibrosis underlies the end-stage pathogenesis of several retinal diseases including age- related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Fibrosis results from neovascularization or injuries and is part of the wound healing response characterized by the formation of excessive accumulation of extracellular matrix (ECM) connective tissue. Subretinal fibrosis can generate contractile force, cause scar formation, massive subretinal hemorrhage, and retinal detachment, therefore disrupting retinal structures and eventually leading to legal blindness. The cellular and molecular mechanism of subretinal fibrosis is still unclear, and the clinical treatment for this condition is very limited. Myofibroblast is a predominant cell type that are critically involved in fibrosis. The cellular contribution to myofibroblasts is diverse and heterogenous, with multiple cell types involved. For example, RPE cells contribute to fibrosis through epithelial-mesenchymal transition (EMT), endothelial cells contribute to fibrosis through endothelial-mesenchymal transition (endMT), and macrophages contribute to fibrosis through macrophage-mesenchymal transition (MMT). To fully understand the mechanism of subretinal fibrosis, the role of myofibroblast and the contribution of different cell-types to subretinal fibrosis need to be resolved. MicroRNAs (miRNAs or miRs) are endogenous small molecules which can regulate diverse pathways in different cell types. Several miRNAs, including miR-29, miR-24, and miR-21 have been associated with fibrosis. Our preliminary data showed that miR-24 overexpression inhibits EMT, endMT and fibrosis by regulating TGF-β/SMAD3 and LIMK2/MRTF pathways, suggesting miR-24 could serve as an ideal therapeutic target for subretinal fibrosis by targeting two major pathways in different cell types. The broad goal of this proposal is to elucidate the cellular contribution, identity and function of myofibroblasts in subretinal fibrosis and test the therapeutic potential of miR-24 in subretinal fibrosis. We hypothesize that: (1) myofibroblasts from multiple cell lineages could contribute to subretinal fibrosis; and (2) miR-24, can repress EMT, endoMT and MMT by regulating TGF-β/SMAD3 and LIMK2/MRTF pathways, therefore representing an excellent “one drug/multiple targets” model for treating subretinal fibrosis in AMD and PVR. Two Aims will be pursued: Aim I is to define the function, identity, and origin of myofibroblasts in subretinal fibrosis; and Aim II is to determine the therapeutic potential of miR-24 in subretinal fibrosis. Successful completion of the proposed project will pave the way to study the mechanism and therapeutics of subretinal fibrosis in human AMD and PVR patients.