NIHRDataInsights/HRCSData huggingface dataset:
Title: Understanding C9orf72 Hexanucleotide Repeat Linked Toxicity
Funder: Medical Research Council

Abstract: The increase in average life expectancy has led to a dramatic rise in the number of people globally affected by age-related diseases, in particular neurodegenerative diseases(NDs). Concerted research efforts have successfully identified many of the causative agents of ND. However, the molecular cascades downstream of toxic insults leading to neuronal cell death remain unknown, and there are currently no cures. A major, outstanding question is why cell death is triggered only in specific neuronal populations, while others remain 'protected' or are less susceptible to the accumulation of insults. To understand how the accumulation of toxic insults triggers cell death in specific neuronal populations, we will focus on C9 toxicity. We have previously developed a fly model of the CCCCGG hexanucleotide repeat expansion(C9), which is the most common cause of sporadic and familial Amyotrophic Lateral Sclerosis(ALS) and Frontotemporal Dementia (FTD). FTD is the second most common early onset dementia, and ALS results in early muscle paralysis and death by respiratory failure within 2-3 years of diagnosis. We have shown in our fly model that C9 repeats are highly toxic to neurons, and large-scale genetic screens and RNA sequencing(RNA-seq) revealed that mitochondrial physiology is a potential modulator of C9 toxicity. Moreover, analyses of depleted transcripts in our C9 fly model have also identified neuronal populations that are vulnerable to C9 toxicity. We propose to further narrow down this identification of neuronal populations vulnerable or resistant to C9 toxicity and then examine their population-specific expression profile, thereby identifying pathogenic and protective cellular responses to toxic insults. This analysis will therefore provide disease relevant new mechanistic insights into the selective vulnerability of neuronal populations to different toxic species and uncover novel candidates for therapeutic development.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Beyond The Basal Ganglia: Spinal Circuit Dysfunction As A Final Pathway For Movement Disorganisation In Tor1a Dystonia
Funder: Medical Research Council

Abstract: DYT1 is a genetic and severe form of primary torsional dystonia characterised by involuntary, excessive, disorganised muscle activity caused by a mutation in TOR1A. Current hypotheses localise dysfunction to brain circuits. Yet it is the spinal cord that is the CNS structure that ensures movements are organised to produce a behaviour. We therefore hypothesise that spinal cord pathophysiology directly leads to the phenotype of dystonia. We will perform site- and cell-type specific manipulations of Tor1a expression to address two specific aims: (1) determine the degree to which dysfunctional spinal circuits contribute to movement disorganisation in Dyt1 dystonia; and (2) determine whether dysfunction of a class of spinal inhibitory interneurons contributes to the pathophysiology of this dystonia. To address these aims, we have developed a new model of Dyt1: a conditional ready model of Tor1a in which exons 3-5 are flanked by FlpO-sensitive target sites. Cdx2-FlpO mice will be used to restrict Tor1a deletions to the spinal cord, sparing Tor1a function in the brain. Using molecular, electrophysiological (in vivo and in vitro), and behavioural techniques, we will quantify the degree to which spinal cord circuits contribute to the phenotype. We will compare these findings with those obtained through another new model in which Tor1a will be spared in the spinal cord and deleted in the brain. Next, we will use intersectional FlpO-Cre deletion of Tor1a-frt/flox to combine site- (spinal) and cell-type specificity, targeting a class of spinal inhibitory neurons with bi-allelic Tor1a deletion. By the end of this proposal we will have a solid understanding of how spinal circuit dysfunction contributes to movement disorganisation in Tor1a dystonia. This understanding could lay the foundation for possible new targeted therapies to treat signs and symptoms in order to improve the quality of life of people with this challenging disease.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Investigating polyamines as a treatment target for mitochondrial disease
Funder: Medical Research Council

Abstract: Mitochondrial diseases are a group of genetic disorders resulting from defects in the mitochondrial respiratory machinery, which can cause death in early childhood and are largely untreatable. Mitochondrial diseases frequently affect the nervous system, causing loss of neuronal function and neurodegeneration. Mitochondrial dysfunction triggers mitochondrial stress signalling via the transcription factor ATF4. Mitochondria are central players in metabolism, shaping the metabolome and ATF4 is a key regulator of metabolic gene expression. We hypothesise that in mitochondrial disease, ATF4 disrupts polyamine metabolism, contributing to the neurological phenotypes. In this project, we will use a Drosophila model of the mitochondrial disease Leigh syndrome that we have developed and an established Leigh syndrome mouse model to understand how ATF4 regulates polyamines and provide direct evidence that disruption of polyamine metabolism contributes to the disease. Metabolomics and analysis of polyamine enzyme gene expression will be used dissect the role of ATF4 in the brain in Leigh syndrome. We will then use state-of-the-art genetic and imaging techniques, combined with functional assays, to understand the mechanism by which polyamine metabolism contributes to this disease. Finally, we will test whether modulating levels of the polyamine spermidine alleviates the neurological phenotypes in Drosophila and mouse Leigh syndrome models. This project will lead to a greatly improved understanding of the molecular basis of mitochondrial disease and the pre-clinical validation of potential new treatment.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.1 PHARMACEUTICALS
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Can learning deficits in neurodevelopmental disorders be reversed by restoring gene function in the adult brain?
Funder: Medical Research Council

Abstract: This project aims to determine if genes mutated in individuals with intellectual disability have direct roles in learning and memory and if learning deficits can be reversed by restoring gene function in the adult brain. >1.5 million people in the UK suffer from intellectual disability. It is widely assumed that these conditions are caused by abnormal brain development, and therefore irreversible. However, this may not be so. A substantial proportion of genes associated with intellectual disability encode chromatin regulators. These factors function at the level of the epigenome, and therefore control processes that are reversible. Thus, if we can identify which of these genes control the processes necessary for learning and memory, and determine to what extent learning deficits can be ameliorated by restoring gene function, we can envisage the development of targeted treatments for these conditions. This project will focus on four of these chromatin regulators and will answer two critical questions. Do these genes directly control processes necessary for learning in post-mitotic neurons? Can restoring the functions of these genes in neurons in the adult brain rescue learning and memory deficits? First, we will delete genes either in newborn, excitatory neurons of the embryonic neocortex and hippocampus, or mature excitatory neurons of the hippocampus only. Where these approaches are not possible due to the lack of an appropriate conditional mouse line, we will knock down gene expression in all cell types of the hippocampus. The effects on hippocampus-dependent learning will be assessed. Next, we will establish mutants that model the human conditions and restore gene expression in mature, excitatory neurons of the hippocampus to test if we can reverse learning deficits. These experiments are critical to guide future research on the molecular and cellular mechanisms of learning, with the aim of developing approaches to restore cognitive function.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;3.2 INTERVENTIONS TO ALTER PHYSICAL AND BIOLOGICAL ENVIRONMENTAL RISKS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Neurotransmitter imaging to understand seizure mechanisms
Funder: Medical Research Council

Abstract: Pharmacoresistant focal epilepsy is often accompanied by interictal discharges (IIDs). We have recently used Ca2+ fluorescence microscopy to show, in awake head-fixed mice, that IIDs and seizures evoked by chemoconvulsants are initially indistinguishable. Why do IIDs abate whilst seizures escape from local inhibitory restraint and propagate to contiguous cortical areas? By imaging GABA and glutamate using fluorescent reporters (iGABASnFR and igluSnFR), we have detected striking spatiotemporal differences between the two neurotransmitters, consistent with a halo of inhibition surrounding the ictal 'core'. Pilot data also suggest that a decrease in GABA release with each IID precedes the occurrence of a seizure. Why is GABA release impaired at the ictal core and how does it fail to constrain pathological activity? We will combine neurotransmitter imaging with Ca2+ fluorescence imaging confined to different subsets of interneurons at different distances from the ictal core. We will also use closed loop optogenetic manipulations to test the hypothesis that interneurons are pushed into depolarization block. We will, moreover, use structured illumination to confine the optogenetic manipulations to different sites in relation to the ictal core and wavefront. In parallel, we will ask how the emerging understanding applies to spontaneous seizures in a model of focal cortical dysplasia. We have confirmed that this important cause of pharmacoresistant epilepsy can be modelled by in utero electroporation to manipulate mToRC1 signalling. We will use a miniaturized head-mounted microscope to understand if IIDs and seizures arise from the dysplastic core or surrounding area, and relate the release of neurotransmitters to activity in different populations of neurons. The outcome of will help to refine advanced therapies that we and others are developing to replace epilepsy surgery and offer treatment to many people who currently have not prospect of seizure freedom.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Identifying the regulation of striatal dopamine function by striatal astrocytes in health and parkinsonism
Funder: Medical Research Council

Abstract: Emerging evidence indicates that brain astrocytes not only regulate ion balance and blood flow, but also regulate activity of synapses and neural circuits. Astrocytes express receptors and transporters for many transmitters, and consequently, they respond to neurotransmitter input, regulate transmitter levels and release gliotransmitters. Through these mechanisms, astrocytes can act as an extension of neural circuits to regulate neuronal output. With the emergence of new molecular tools to modulate and image astrocyte activity, previously neglected questions about astrocyte-neuron interactions can excitingly now be addressed for the first time. The neurotransmitter dopamine (DA) is critical to the selection and learning of motivated behaviours, and is dysregulated in disorders spanning Parkinson's disease (PD) to addictions. The fundamental questions of whether astrocyte activity regulates the dynamic release and function of striatal DA, and whether there are changes to astrocyte biology in PD that impact on DA function, have not previously been investigated. We have obtained key pieces of data which support the hypotheses that (1) striatal astrocytes support DA release and (2) this interaction becomes maladaptive in PD. In this timely project, we will exploit new molecular tools that permit targeted manipulation of astrocyte activity to test these hypotheses fully. We will identify: whether and how striatal astrocytes govern DA output on a sub-second timescale; mechanisms and mediators (with a focus on GABA transporters and purinergic gliotransmitters); impact on DA-dependent behaviours; and dysregulation in mouse models and human PD. The findings of this project could radically revise current understanding of the mechanisms that regulate dopamine function, and contribute to a paradigm shift from current neuron-centric views of the mechanisms that gate neural circuits. This work could also provide candidate targets for new treatments for dopaminergic disease.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Dissecting the molecular mechanisms of lysosome:ER contact site formation and their relevance to neurodegenerative disease
Funder: Medical Research Council

Abstract: Membrane contact sites are important platforms for lipid transport and the ER:lysosome interface is emerging as a key regulator of lipid exchange. We have recently identified a role for the late endosomal sterol binding protein Niemann-Pick type C protein 1 (NPC1), in tethering lysosome-ER contacts through interaction with an ER-localised lipid transfer protein, Gramd1b. NPC1 is required for egress of dietary cholesterol from lysosomes; lack of functional NPC1 protein causes cholesterol to accumulate in the lysosome, manifesting in the severe progressive neurodegenerative disease NPC. Here, we aim to define the molecular architecture of NPC1-regulated contact sites. Our new data suggests the NPC1 cytoplasmic tail mediates ER contact. Using our established tools, we will examine the role of the cytoplasmic tail and effect of NPC1 sterol-sensing domain mutations in contact site formation. Our preliminary data suggests that egress of sphingolipids, which also accumulate in lysosomes in NPC, may too be mediated by lysosome:ER contacts. This study will elucidate the relationship between the lysosome:ER interface and the lipid environment. We found that expanding the lysosome:ER interface restored cholesterol transport to the ER and rescued cholesterol accumulation in cellular models of NPC. To test if contact site expansion can also be effective in vivo, we will use morpholino oligonucleotides targeting regulators of the small GTPase Rab7, to expand the lysosome:ER interface. High resolution microscopy, biochemistry and automated analysis tools will be used to relate contact site extent to cholesterol distribution, sphingolipid metabolism and movement phenotypes in zebrafish NPC models. The proposed research will provide molecular and mechanistic insight into the relationship between NPC1-dependent contact sites and lipid metabolism and may lead to a novel therapeutic strategy for NPC and other neurodegenerative diseases with lipid storage defects.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;6.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Developing personalised medicine for CLN3 disease
Funder: Medical Research Council

Abstract: Mutation of the CLN3 gene causes a lysosomal disease with a wide spectrum of symptoms including classic juvenile neuronal ceroid lipofuscinosis (NCL), a fatal devastating neurodegenerative disease beginning with loss of sight as well as adult onset visual failure. CLN3 encodes a highly conserved intracellular membrane protein whose function is not fully defined, although it is important under conditions of stress and the latest understanding is that it may transport ions across the lysosomal membrane. There is evidence for multiple CLN3 transcripts and and further novel isoforms arise in the presence of the 1-kb deletion. This project aims to develop genetically and transcriptionally accurate models of CLN3 disease that can be used to test novel therapies, enable a molecular, cell, and whole body understanding of the consequences of disease-causing mutations and CLN3 dysfunction. Our main objectives are: 1. CLN3 transcript profiling of patients with classic juvenile CLN3 disease; 2. Genetically accurate zebrafish models of CLN3; 3. Transcript profiling of CLN3 disease models; 4. Exhaustive phenotypic characterisation of zebrafish CLN3 models; 5. Functionality of novel CLN3 transcripts. This programme of work will use a range of methodologies, with an emphasis on longread RNAseq supported by bioinformatic analysis, advanced gene editing techniques in zebrafish including CRISPR/cas9 gene editing, specialised phenotypic assays for zebrafish such as electroencephalography to detect seizures and electroretinography to assess eye function, supported by classic molecular and cell biology techniques. Consideration has been given to sample size for RNA extraction and phenotypic analysis.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: A single-cell transcriptomic map of the human developing cortex in Down syndrome
Funder: Medical Research Council

Abstract: Proper wiring of cortical circuits is a critical step in human brain development and maturation of high-order cognitive abilities. Despite their pivotal role, we do not yet clearly understand how human cortical circuits assemble in vivo, nor why this process can fail, leading to cognitive disturbances in neurodevelopmental conditions such as Down syndrome (DS), a major cause of congenital intellectual disability triggered by a trisomy of chromosome 21. My team recently discovered reduced synchronized excitatory network activity in the immature DS cortex, which could contribute to the progression of cognitive symptoms. The overall goal of this proposal is to capture the mechanisms of cortical circuit dysfunction in DS. I will achieve this by revealing the molecular and cell type-specific landscape of the DS cortex from both human post-mortem fetal brain samples and induced pluripotent stem cell (iPSC)-derived cortical tissue grafts by single-nucleus RNA sequencing. This atlas of human neocortical cell types, their relative proportions and the differentially regulated genes will constitute an important resource for the scientific community that will be made publicly available. This proposal will thus deliver new fundamental insights into how the generation of cells and circuitry of the human neocortex are perturbed in DS. Since cortical excitatory circuit activity dysfunction was detected at early stages of fetal brain development, and is likely associated with early signs of cognitive impairment in DS, clarifying the underlying mechanisms could lead to the identification of new intervention targets and the design of more effective cell type specific therapies for DS.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: A Network Approach to Gene Therapy for Refractory Epilepsies
Funder: Medical Research Council

Abstract: Drugs fail in many people with epilepsy, principally because they affect the whole brain. Surgery to destroy regions implicated in seizure generation is only suitable in very few patients. Gene therapy offers a rational alternative. Hitherto, it has relied upon treating a poorly defined epileptogenic focus, ignoring the emerging understanding of seizures as network phenomena. Aim 1 is to identify the regions of the brain that are critical for the spread of seizures, using implanted Neuropixels probes, which allow the detection not only of local field potentials (which are dominated by synaptic currents) but also of action potentials across multiple brain regions. Aim 2 is to determine whether acute manipulation of putative nodes of ictogenic networks, including piriform cortex and thalamic targets, is sufficient to block seizure propagation. As the project progresses new potential nodes arising from Aim 1 will be tested. Towards the end of the programme, we will determine which nodes or combinations should be treated to enhance treatment efficacy. Aim 3 is to develop new tools optimised to stop the spread of seizures by potentiating potassium conductances. We will, in particular, focus on strategies for autoregulatory inhibition whereby a pathological glutamate elevation, as occurs in seizures, opens potassium channels. We will use human proteins to minimise obstacles to translation. We will also explore the potential of a secreted protein that upregulates potassium channels and has been implicated in both genetic and autoimmune epilepsy. These tools will be assessed in vitro and the most promising ones will be progressed to in vivo pre-clinical studies. Throughout, we will use models of acute seizures and different aetiologies of epilepsy (hippocampal sclerosis, focal cortical dysplasia and inherited genetic mutations) to maximise clinical relevance. The work will feed into a translational pipeline that addresses an enormous health burden.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL
Title: Functional characterisation of newly identified Alzheimer's Disease associated genes in human and invertebrate model systems
Funder: Medical Research Council

Abstract: Alzheimer's disease is a complex genetic condition with a strong hereditary component, characterised by dementia associated with incurable neurodegeneration. The European Alzheimer DNA BioBank (EADB) study brought together European GWAS consortia to conduct the largest GWAS to date, defining 75 genetic loci associated with increased susceptibly. 42 of these loci are novel, including genes with protein coding variants involved in the processing of APP, with expression data suggest an unexpected microglial role for these novel genes in APP processing. Using combined Drosophila phenotypic screening and human iPSC-neuron and glia cell culture models, we will identify priority novel genes from EADB study and dissect their contribution to disease relevant phenotypes. First, we will use fly models of AD to assess the contribution of all novel susceptibly genes to behavioural, survival and amyloid pathology associated phenotypes including highly sensitive immunoassays to define APP proteolytic cleavage products. We will use findings from our fly experiments to triage genes with the strongest disease modifying activity, which will be taken forwards for further characterisation in hiPSCs derived neurons and glia. Expression of triaged AD susceptibility genes will be disrupted by CRISPR/Cas9 gene editing, in isogenic hiPSCs expressing high or low levels of APP. We will differentiate hiPSCs to mature neurons, where contribution of AD susceptibility genes to electrophysiological function, Ca2+ signalling, and amyloid processing will be defined. Mutant hiPSCs will also be differentiated to microglia, with immune stimulated cytokine release, morphological phenotypes and phagocytic activity assessed. Our innovative fly-human study will identify AD susceptibility genes from the large EADB gene list to prioritise for future research, dissect the contribution of these genes to AD pathology and potentially identify targets for therapeutic intervention.


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;5.2 CELLULAR AND GENE THERAPIES
Health categories: CONGENITAL DISORDERS;NEUROLOGICAL