Genetic and cellular basis of functional cilia assembly

Cilia are specialized structures found on the surface of most mammalian cells, playing key sensory and sometimes movement functions. Defects in cilia function result in a broad range of genetic diseases termed ciliopathies. These can have devastating effects on human development (birth defects) or postnatal health, including blindness, obesity and kidney failure. Hundreds of genes are involved in building and maintaining this highly conserved structure, which is highly dynamic and biochemically complex. However, we know very little about why some cilia types are more affected in human disease than others. In order to understand how different cell types have configured cilia as specialized signaling ‘antennae’ to interpret environmental signals, we have engineered a series of mice expressing the latest molecular tags and markers to allow us to exquisitely profile cilia subtypes, in both healthy and diseased states.
Ciliopathies are rare genetic diseases, for which there are no effective treatments. For a subset of these diseases affecting accessible tissues, like the airways of primary ciliary dyskinesia (PCD) patients, we have been developing genome editing strategies to determine can we fix the right cells types efficiently and whether this is treatment well-tolerated.
We hope to better understand the disease mechanisms underlying ciliopathies in order to develop effective diagnostic as well as therapeutic strategies to benefit patients and their families.

Ciliopathies are a diverse class of human genetic diseases, with over 20 recognized syndromes caused by mutations at ~100 different loci. While mammalian cilia are ubiquitous and highly conserved structures, the clinical features associated with their dysfunction are highly pleiotropic with varying degrees of severity and penetrance among tissues. While the causative genes are now being rapidly identified, the cellular and developmental basis for this phenotypic complexity remains poorly understood and controversial. In this programme we aim to:
1. Investigate the cellular pleiotropy of ciliopathies by determining why different cell types vary in their vulnerability to mutations affecting cilia, despite their ubiquity. To better understand cilial diversity and how this results in variable phenotypic consequences upon ciliary dysfunction, we are building tools to interrogate clinically relevant cilial types at a molecular, structural and physiological level. We are engineering a series of precisely-targeted in vivo proximity labelling tracers to common cilial transport machineries and novel cilial biosensors to track cilial dynamics in vivo, in healthy and diseased states.
2. Develop therapeutic strategies for somatic gene editing in ciliopathies, focusing on improving delivery to the correct cell type, and biasing editing of intragenic mutations to therapeutically beneficial events. The recent therapeutic game-changer for rare human genetic disease is the possibility of gene correction using targeted CRISPR technology for precise and efficient corrective genome-editing. If targeted to the most relevant cell type(s), this offers the possibility of a somatic cure for some genetic diseases in which affected cell types are accessible, such as the postnatal airways (affected in primary ciliary dyskinesia: PCD) and the eye (affected in retinitis pigmentosa: RP). Importantly both PCD and RP are characterized by their staggering polygenic natures: over 40 and 100 genes are implicated in PCD and RP respectively, which complicates a conventional “one-size-fits-all” gene therapy for all patients. In contrast, therapeutic gene editing could be personalized based on an individual’s genetic mutation(s). However, there remain at least two sizeable obstacles to making gene editing a therapeutic reality, namely (a) targeted delivery of the editing machinery and (b) improving repair efficiency. To address these problems, we have developed fluorescent reporter mouse models that allow a sensitive read-out of gene-editing events in time and space, which we will use to investigate how best to target cells of interest safely and in a therapeutically effective manner.
Our aims fully align with the Unit’s mission to understand genetic disease and disease mechanisms, as well as its emphasis on the genome and brain biology: our whole organism approach is essential for understanding why different tissues or organs are particularly susceptible to perturbation across the wide phenotypic spectrum of human ciliopathies.