Evaluating the role and therapeutic potential of cytoskeletal dysregulation in CRB1-linked retinal degenerations

01.11.2022 bis 31.10.2025

Based on long-term cultivated retinal organoids derived from hiPSCs and based on recombinatly produced crb1 offered as a bait for a proteome wide interactome screen, we have generated knowledge, hypotheses and provide candidate targets for a future intervention into crb1 associated retinal degeneration in the previous funding period of the SPP. In the search for understanding the pathomechanisms and variant clinical manisfestation behind this form of RD, we now propose to in depth analyse and validate our findings with a focus on a role for crb1 in cytoskeletal organisation and dynamics. Using patient derived organoids as well as knock-outs and knockdowns associated with crb1 defects, we now aim to study molecular defects caused by crb1 mutation in a hypothesis based fashion. For that, we further use control- and patient specific iPS and generate retinal organoids thereof carrying homozygous mutations in the CRB1 gene that we were successful to establish in funding period 1. We will investigate patient specific deregulations of pathways associated with cytoskeletal organisation and changes in protein interactions and transcript patterns dependent on CRB1. Here we will apply pathway walking, a strategy developed by Ueffing and co-workers. This will be complemented by histological and high-resolution microscopy imaging techniques (2-Photon, STED und EM) to analyse topological (immunohistochemistry) and microanatomical features dependent on CRB1. Given that we and others do see variant disease severity in patients, we will continue to comparably analyse organoids derived of patients with different disease severity to look for modifiers of disease as well as mechanisms for protection. This requires a holistic view on the role of CRB1 within retinal development, which we will continue to gain by combining a deep mutli-omics approach in combination with advanced bioinformatics. Based on a deeper understanding on the role of CRB1 in cellular signaling pathways associated to cytoskeletal organization we attempt to gain insights into possible endogenous protective mechanisms associated with CRB1 retinal degeneration, which can serve as future handles for therapy development.