CAPN5-PDGF Signaling in Vitreoretinopathy

 描述(申请人提供)：玻璃体视网膜病变和葡萄膜炎(眼内炎症)的分子靶点知之甚少。这一建议建立在我们令人兴奋的发现的基础上，发现了一种钙激活的蛋白酶CAPN5(calain-5)，它是常染色体显性遗传性新生血管性炎性玻璃体视网膜病变(ADNIV)的原因，并且CAPN5处理PDGFB信号。CAPN5是第一个非综合征性葡萄膜炎基因，为光感受器变性引起的炎症的机制治疗提供了一种高度创新的分子遗传学方法。光感受器表达CAPN5，在小鼠中hCAPN5-R243L功能突变的获得显示了人类ADNIV疾病的所有表型。视网膜光感受器可能对CAPN5的突变特别敏感，因为高细胞内钙是调节光感受器暗适应所必需的，也是足够的。我们的长期目标是找到更好、更具体的治疗炎症性玻璃体视网膜病变的方法。我们的目标是利用体外和体内细胞培养和小鼠模型来确定负责控制CAPN5活性的机制。我们还将研究不受控制的CAPN5活性如何导致其底物之一--血小板衍生生长因子B(PDGFB)的信号异常，以及这种信号如何导致随后的ADNIV表型。我们的中心假设是，不受控制的、钙激活的CAPN5通路通过异常的PDGFB信号导致ADNIV视网膜变性和葡萄膜炎。通过创造一个新的小鼠模型，我们将能够识别新的治疗靶点。我们的具体目标是(1)剖析ADNIV CAPN5在细胞中的自蛋白分解效应，(2)确定ADNIV CAPN5是否过度切割PDGFB以上调信号，以及(3)在临床前小鼠模型中测试PDGFB缺失是否拯救ADNIV表型。冲击力。我们希望不仅能更好地了解Calain的活性和PDGFB在眼病中所起的作用，而且还能确定可能适用于许多眼病的新的治疗靶点。我们的工作应该有助于确定PDGFB信号在ADNIV和其他玻璃体视网膜退行性疾病中的作用。

 DESCRIPTION (provided by applicant): The molecular targets for vitreoretinopathy and uveitis (intraocular inflammation) are poorly understood. This proposal builds on our exciting discovery of a calcium-activated protease, CAPN5 (calpain-5), as the cause of Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy (ADNIV), and that CAPN5 processes PDGFB signaling. CAPN5 is the first nonsyndromic uveitis gene, and makes possible a highly innovative molecular-genetic approach for mechanism-based therapies for inflammation induced by photoreceptor degeneration. Photoreceptors express CAPN5, and an hCAPN5-R243L gain of function mutation in mice shows all the phenotypes of human ADNIV disease. The retina photoreceptors might be particularly sensitive to mutations in CAPN5, because high intracellular calcium is necessary and sufficient to regulate dark adaptation in photoreceptors. Our long-term goals are to find better and more specific treatments for inflammatory vitreoretinopathy. Our objective is to use in vitro and in vivo cell culture and mouse models to determine the mechanisms responsible for controlling activity of CAPN5. We will also investigate how uncontrolled CAPN5 activity leads to aberrant signaling of one of its substrates, platelet-derived growth factor B (PDGFB), and how this signaling results in the subsequent ADNIV phenotypes. Our central hypothesis is that an uncontrolled, calcium-activated CAPN5 pathway leads to ADNIV retinal degeneration and uveitis through aberrant PDGFB signaling. By creating a new mouse model we will be able to identify new therapeutic targets. Our specific aims are to (1) Dissect the ADNIV CAPN5 autoproteolysis effect in cells, (2) Determine if ADNIV CAPN5 hyperactively cleaves PDGFB to upregulate signaling, and (3) Test if PDGFB loss rescues the ADNIV phenotype in a preclinical mouse model. Impact. We expect to gain not only a better understanding of calpain activity and the role PDGFB plays in eye disease, but also to identify new therapeutic targets that may be applicable to many eye diseases. Our work should help determine the role of PDGFB signaling in ADNIV and other vitreoretinal degenerative diseases.