Modelling inherited developmental ocular disorders using in vitro organoids

遗传性发育障碍占儿童视力障碍的很大一部分，但对其分子和细胞原因的了解还远未完成。在早期眼发育过程中，干细胞必须在增殖和分化之间平衡命运决定，同时经历细胞迁移和形态发生以防止此类疾病。细胞命运决定由内在因素（如基因网络）和外在因素（如来自周围组织和细胞外基质的机械信号）控制。机械信号在眼睛发育过程中至关重要，因为机械换能器雅普的突变导致人类缺损，这是一种罕见的发育障碍，由视杯折叠和融合失败引起。重要的是，在许多患者中同时出现缺损（一种结构性疾病）和小眼症（一种细胞命运障碍），表明发育中的眼睛中机械环境和细胞命运之间存在机械联系。假设是突变主要导致形态发生并发症（即缺损），然后反馈影响细胞命运，导致缺损和小眼球同时发生。该项目将涉及将临床报告中的突变引入人类胚胎干细胞和小鼠胚胎干细胞，以建立视网膜分化和视杯类器官方案中的缺损/小眼畸形体外模型。这将随后用于探索疾病机制和控制眼睛中的细胞命运决定。这些发现将促进对发育性眼部疾病病因学的理解，并将更广泛地适用于其他组织的发育和再生。该项目还将为使用体外类器官作为发育性眼部疾病的分子诊断方法铺平道路。从人类iPSC中产生具有功能性光感受器的三维视网膜组织。Zhong，X等人（2014）Nature Communications.New variant and expression studies provide further insight into the genotype-phenotype correlation in YAP 1-related developmental eye disorders. Holt R et al.（2017）Scientific Reports.

Inherited developmental disorders account for much of childhood visual impairment, yet knowledge of their molecular and cellular causes is far from complete. During early eye development stem cells must balance fate decisions between proliferation and differentiation at the same time as undergoing cell migration and morphogenesis to prevent such disorders. Cell fate decisions are controlled by intrinsic factors, such as the gene network and extrinsic factors, such as mechanical signals from the surrounding tissue and extracellular matrix. Mechanical signals are crucial during eye development as mutations in the mechano-transducer YAP lead to coloboma in humans, a rare developmental disorder arising from failure in optic cup folding and fusion. Critically, the co-occurrence in many patients of coloboma, a structural disorder, and microphthalmia, a cell fate disorder, suggests a mechanistic link between the mechanical environment and cell fate in the developing eye. The hypothesis is that mutations that primarily lead to morphogenetic complications (i.e coloboma), then feedback to affect cell fate, resulting in co-occurrence of coloboma and microphthalmia. This project will involve introducing mutations from clinical reports into humanESCs and mouseES to set-up an in vitro model of coloboma/microphthalmia in retinal differentiation and optic cup organoid protocols. This will subsequently be used to explore the disease mechanisms and the control of cell fate decisions in the eye. These findings will advance understanding of the aetiology of developmental ocular disorders and will be more broadly applicable to the development and regeneration of other tissues. This project will also pave the way for using in-vitro organoids as a method for molecular diagnosis of developmental eye disorders.Generation of three-dimensional retinal tissue with functional photoreceptors from human iPSCs. Zhong, X et al. (2014) Nature Communications.New variant and expression studies provide further insight into the genotype-phenotype correlation in YAP1-related developmental eye disorders. Holt R et al. (2017) Scientific Reports.