Title: Harnessing self-organisation in human retinal organoids
Funder: The Academy of Medical Sciences

Abstract: Human induced pluripotent stem cells (hiPSCs) can generate entire synthetic retinas, called retinal organoids. I aim to validate the first computer model to explain how retinal organoids can ‘self-organise’ from stem cells. This is a potentially powerful tool for advancing retinal organoid technologies and applications. We recently discovered a ‘self-organising’ gene network that appears to initiate spontaneous retinogenesis. Simulations show that it generates a foundational Turing pattern for the retina using three genes – the eye ‘master control gene’ Pax6 and its novel targets, Transforming growth factor-beta 2 (Tgfb2) and Follistatin – ‘PFT’. The project has three objectives: 1) Test this gene network’s impact on retinal self-organisation in hiPSCs. We will knock-down this gene network in hiPSCs while testing their ability to differentiate into well-patterned retinal primordia. 2) Test the predictive computer model by measuring diffusion of key gene products. We will test a potentially impactful model prediction: that manipulation of Follistatin and Tgfb2 protein diffusion can influence self-organisation. Their diffusion rates will be measured in laminin and Matrigel – extra-cellular matrix (ECM) substrates commonly used for organoid culture. 3) Identify genomic cis-regulatory elements (CREs, ‘enhancers’) that drive this network’s expression. We will identify ‘enhancer’ elements within the genomes of differentiating human iPSCs via ATAC-Seq. Their identification will connect this network to other important eye genes and help to unmask non-coding mutations underlying congenital malformations.

Lay abstract: The retina – the light-sensitive tissue at the back of our eyes – can be grown in the lab from human stem cells. These synthetic retinas have a great potential for helping blind people. - They provide a means of investigating why some children are born blind by ‘modelling’ human embryonic or foetal retinas, which are otherwise unavailable for study. - They can provide an unlimited source of tissue for testing drug candidates to treat blindness, or to identify those that may cause blindness. - They can supply healthy cells for use in ‘cell replacement’ therapies to treat blindness due to ageing or injury and can be derived from patients’ own cells to ensure compatibility with their immune systems. Retinas grown from stem cells are still a new technology – they can be unpredictable and thus difficult to control. This is largely because we don’t fully understand how they grow or how we can control them. I wish to investigate the ‘how’ in order to make lab-grown human retinas a reliable tool for understanding, treating and reversing blindness. Recent discoveries have led us to develop the first computer model of lab-grown retinas. Similar to weather or economic forecasting, this allows us to forecast how well synthetic retinas might grow in different situations, making them more predictable – an important step forward. This project aims to test the reliability of these forecasts and to begin using them to control the growth of synthetic human retinas.

Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: EYE