Elucidation of the Molecular Mechanisms Driving Genetically-Induced High Myopia

摘要 本次K08临床科学家导师研究职业发展奖申请的目标是 为候选人提供建立独立研究计划所需的高级技能 单基因高度近视(HM)和遗传性视网膜营养不良(IRD)的发病机制和治疗。 我们的总体假设是，转化生长因子β信号的增加推动了HM的进展和结构变化 在马凡综合征(MFS)的病理性近视(PM)的后段和Rbp3介导的 视网膜色素变性(RP)。为了检验这一假设，具体目的是：1)确定Smad2/3的程度 激活有助于MFS和Rbp3-/-小鼠的近视进展、PM变化和视网膜变性；2) 确定转化生长因子β依赖的丝裂原活化蛋白在近视进展、PM改变和视网膜变性中的作用 在MFS和Rbp3-/-小鼠中。这是基于对文献的广泛回顾和我们高质量的初步 数据显示：1)MFS小鼠的眼轴长度(AL)和-9D近视移位显著大于MFS小鼠 2)MFS小鼠眼表现出Smad2/3和MAPK(ERK1/2，JNK1/2，p38)激活增强。 睫状体和视网膜；3)ERK抑制后MFS小鼠的AL和近视移位减少；4)Smad3-/-小鼠 与WT相比，表现出较短的AL和显著的远视移位。这些数据表明转化生长因子β 下游通路代表着治疗近视和/或MFS中PM的新靶点。先前的研究表明 RBP3功能缺失突变导致人类常染色体隐性遗传性RP伴HM(-12至-17D)，而 Rbp3-/-小鼠表现出明显的AL和近视移位增加，以及体内和体外进展的证据 视网膜变性。这为评估转化生长因子β信号在这种病因上不同的疾病中的作用提供了机会。 单基因近视的形式，目的是确定和瞄准疾病进展的常见驱动因素。 候选人提出了一项全面的培训计划，将正式课程、会议、 研讨会和研讨会由他的多样化、经验丰富的指导团队监督。他的具体培训目标 包括：1)完善他在小鼠近视和PM体内表型的知识，包括小鼠眼睛 生物测量学、自动屈光、眼底摄影和光学相干断层扫描(OCT)；2)发展内窥镜技能。 小鼠IRDS及其并发症的活体表型，包括ERG、OCT和视运动反应(OMR)； 3)加强对小鼠近视和IRD模型的体外组织病理学和生化分析技能， 包括PM改变(例如视网膜脱离、视网膜劈裂、后葡萄肿)和视网膜变性 (如视网膜变薄、光感受器丢失)；4)掌握管理技能，建立成功的独立 实验室；5)培养合作研究的领导能力；6)提高沟通和写作能力 成功申请R01资金；7)继续进行负责任的研究行为培训。他的训练计划 将与上述研究活动协调执行。这项提案的结果将是 用于制定未来的R01研究计划，促进候选人向独立研究的过渡。

ABSTRACT The goal of this K08 Mentored Clinical Scientist Research Career Development Award application is to provide the candidate with advanced skills needed to establish an independent research program investigating the pathogenesis and therapeutics of monogenic high myopia (HM) and inherited retinal dystrophies (IRDs). Our overall hypothesis is that increased TGFβ signaling drives HM progression and structural changes in the posterior segment indicative of pathological myopia (PM) in Marfan syndrome (MFS) and Rbp3-mediated retinitis pigmentosa (RP). To test this hypothesis, the specific aims are to: 1) Determine the extent that Smad2/3 activation contributes to myopia progression, PM changes and retinal degeneration in MFS and Rbp3-/- mice; 2) Define a role for TGFβ-dependent MAPK activation in myopia progression, PM changes and retinal degeneration in MFS and Rbp3-/- mice. This is based on an extensive review of the literature and our high-quality preliminary data demonstrating that: 1) MFS mice have significantly greater axial length (AL) and -9D myopic shift compared to WT littermates; 2) MFS mouse eyes show increased Smad2/3 and MAPK (Erk1/2, Jnk1/2, p38) activation in the ciliary body and retina; 3) AL and myopic shift are reduced in MFS mice after Erk inhibition; 4) Smad3-/- mice display shorter AL and a prominent hyperopic shift compared to WT littermates. These data indicate that TGFβ downstream pathways represent novel therapeutic targets for myopia and/or PM in MFS. Prior studies illustrated that loss-of-function mutations in RBP3 cause autosomal recessive RP with HM (-12 to -17D) in humans, while Rbp3-/- mice show markedly increased AL and myopic shift, as well as in-vivo and ex-vivo evidence of progressive retinal degeneration. This offers an opportunity to evaluate a role for TGFβ signaling in this etiologically-distinct form of monogenic myopia, with the goal of identifying and targeting common drivers of disease progression. The candidate is proposing a comprehensive training plan, combining formal coursework, meetings, seminars and workshops overseen by his diverse, experienced mentorship team. His specific training goals include to: 1) Refine his knowledge of in-vivo phenotyping of myopia and PM in mice, encompassing mouse eye biometry, autorefraction, fundus photography and optical coherence tomography (OCT); 2) Develop skills in in- vivo phenotyping of IRDs and their complications in mice, including ERG, OCT, and optomotor response (OMR); 3) Enhance his skills in ex-vivo histopathological and biochemical analysis of mouse myopia and IRD models, including PM changes (e.g. retinal detachment, retinoschisis, posterior staphyloma) and retinal degeneration (e.g. retinal thinning, photoreceptor loss); 4) Acquire management skills to build a successful independent laboratory; 5) Develop leadership skills in collaborative research; 6) Refine his communication and writing skills to successfully apply for R01 funding; 7) Continue training in responsible conduct of research. His training plan will be executed in coordination with the research activities described above. Results from this proposal will be used to develop a future R01 research plan that will facilitate the candidate’s transition to independent research.