Large-scale randomised controlled clinical trials are an essential part of the evaluation of healthcare treatments including new drugs, surgical techniques and behavioural interventions. Like many other parts of life, ongoing clinical trials have been affected by the global coronavirus pandemic. The cancellation of non-essential medical procedures, restrictions on face-to-face assessments and outpatient non-attendance due to lockdown restrictions, illness or reluctance to visit hospitals or healthcare centres have led to recruitment and data collection being suspended for many ongoing clinical trials. As restrictions start to be relaxed, researchers have the opportunity to restart clinical trials that were interrupted. The questions of whether or not this is worth doing, or of the best way to analyse the data either in a restarted trial or in one that is not restarted, may raise some challenges, however. This project will research statistical tools to help address these questions. These methods will also be of value in other settings when trials are interrupted due to challenges in recruitment or funding, or due to the influence of new results from other research. If a trial is restarted, depending on the clinical area in which the trial is being conducted, there may be differences between the pre-pandemic and post-pandemic periods in the type of patients who enrol in the trial, the exact way in which measurements are taken, or even in the intervention to be assessed, for example for a psychological intervention for which delivery may have changed to being wholly or partially online. These differences, or heterogeneity, need to be accounted for in the statistical analysis, and may mean that a larger number of patients than initially anticipated need to be included in the trial in order to obtain a reliable result. We will identify methods for this analysis and evaluate these in the setting of interrupted trials. As it is important that analysis methods proposed are accepted by all stakeholders, we will organise workshops for clinical trialists, clinical trial statisticians and representatives of regulators, funders, science publishers and patients to discuss and hopefully lead to consensus on the most appropriate methodology. If a trial is not restarted, the number of patients included will be smaller than initially planned. In many cases, particularly those in which patients are followed up in the clinical trial for a long period before the effect of the treatment is finally assessed, some early data may be available for patients recruited shortly before the start of the pandemic. This data may give additional information that can be included in the final analysis. We will explore statistical approaches to best utilise the information available in these data, extending existing methods where this is necessary. In addition to developing and recommending methods for the analysis of trials that are or are not restarted, we will develop methods to help decide which of these is the best option depending on the amount of information already available and the degree of heterogeneity between pre-pandemic and post-pandemic periods that is anticipated. We will also develop methods that allow an analysis of the data already collected but also allow the option of restarting the trial if the results of the trial are not sufficiently clear. Specialist statistical methods are required for this analysis in order to ensure that the risk of an erroneous false positive trial result is not increased. The research team includes experts in clinical trial statistics along with trialists and representatives of trial funders from a range of clinical areas to ensure that the research is applicable in a wide range of clinical trial settings.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two fatal neurodegenerative diseases. A rare form of familial ALS is caused by mutations in the FUS gene that disrupt the nuclear localization sequence leading to cytoplasmic accumulation and aggregation of FUS. Besides genetic cases, FUS is also a component of protein inclusions in a subset of sporadic FTD cases (FTLD-FUS). Thus, cytoplasmic aggregation of the physiologically nuclear FUS protein is a typical feature of a subset of FTD and ALS collectively termed FUS-opathies. Neuropathology strongly suggests that neurodegeneration is directly related to cellular redistribution of FUS. The critical pathogenic event could be either reduced ability of FUS to perform its normal nuclear functions, a toxic gain of function of FUS in the cytoplasm, or a combination of both. FUS is a multifunctional DNA/RNA binding protein with described role as transcription regulator, as it interacts with transcription factors, proteins involved in the transcriptional machinery, as well as proteins involved in splice regulation. FUS can also indirectly modify transcription as it binds epigenetic regulators. Hence, in FUS-opathies, FUS mislocation could induce the cellular redistribution of one, or several, of these crucial proteins, thereby altering the homeostasis of histone modifications and ultimately, gene expression. While a link between chromatin modifications and FUS is suggested by recent in vitro studies, the complexity of chromatin structure modifications potentially regulated by FUS, as well as their downstream effects in the CNS and their pathomechanistic relevance for the disease, have never been studied. Thus, the goal of this project is to elucidate the link between FUS, its mutations and epigenetic modifications of the chromatin in vivo, and to correlate these data with subsequent transcriptomic alterations and phenotypes in transgenic FUS mice and FUS-opathies. We hypothesize that the redistribution of FUS modifies chromatin remodeling dynamics as well as associated epigenomic signatures which could in turn alter genetic programs relevant to cognitive functions and/or neurological deficits. To achieve this we gathered applicants that complement each other ideally by providing all necessary scientific expertise and technical know-how. The analysis of a unique collection of transgenic FUS mouse models with genome-wide and cell type-specific analysis of chromatin alterations (ChIPseq) and transcriptomic (RNAseq including splice variants) changes using next-generation sequencing approaches will allow a detailed dissection of the role of nuclear, cytoplasmic and mutated FUS in regulating chromatin composition and downstream effects as well as its pathogenetic relevance. Identifying a disease specific epigenetic signature would offer a direct path towards therapeutic intervention since various brain permeable small molecular regulators of chromatin remodeling enzymes are available.

Our prime objective is to study interaction between individual cells and other elements of the complex sensory epithelium of the organ of Corti (OC) of the cochlea that determines the exquisite sensitivity and frequency selectivity of mammalian audition. Understanding this interaction is essential for future development of successful treatments for hearing loss, especially those involving recovery of damaged, or replacement of dead, sensory hair cells (HCs). HCs die when damaged by exposure to intense sounds, ototoxicity, disease, age, and genetic disorders. According to WHO, 5% of the world population suffer from irrecoverable hearing loss. HCs in the OC are not replaced when they die. Subsequent hearing depends on remaining, usually low frequency, HCs. Why HCs of non-mammalian vertebrates are replaced, but not those in the mammalian cochlea, is not known. We suggest it is a consequence of the mechanism, by which HCs are tuned to acoustic frequencies. HC frequency tuning of non-mammalian vertebrates is due usually to intrinsic electrical and mechanical resonances and each HC is surrounded by a ring of supporting cells (SC)s that provide a source of replacement HCs. HCs in the mammalian cochlea rely on an extrinsic source of mechanical tuning: the basilar membrane (BM), which constitutes a spiralling acellular ribbon with graded stiffness increasing from apex to the base of the cochlea and is intimately attached to the OC. BM vibrations deflect the HC sensory hair bundles. For the three rows of sensory-motor outer HCs (OHCs) extending the length of the OC, the resultant receptor potentials drive motile forces that feedback energy to the BM. The forces boost BM vibrations close to the frequency place of the OHC, which are transmitted to the row of sensory inner hair cells (IHCs). Resultant deflections of IHC hair bundles generate voltages that control transmitter release and flow of afferent signals in the auditory nerve. To interact with the BM, each OHC is restrained in a complex, flexible, fluid filled cage of specialized, interconnected, SCs comprising pillar cells (PCs) and Deiter's cells (DCs). The cage is proposed to optimize exchange and control of energy between OHCs and other elements of the cochlear partition, including the BM. It has been suggested that their complexity renders mammalian SCs unavailable as sources for HC replacement. Recently, however, we have shown that SCs can be converted into HCs at various postnatal stages, but remain immature, possibly due to lack of interaction with surrounding SCs, which is why it is essential to understand this interaction for restoration of hearing. To this end, we will systematically modify and delete specific proteins in OHCs, PCs, DCs and BM in mice and produce mouse models of age-related and congenital hearing loss. With mice that express channel rhodopsins in OHCs and SCs, we can excite and reversibly change the mechanical properties of the cochlea with light flashes. Through modelling, based on in vivo and in vitro acoustical, mechanical, and electrical measurements, our understanding of the functional significance of interaction between OHCs and their SC cages can be developed and tested, leading to the detailed understanding necessary to fully exploit the exciting regenerative possibilities now becoming available. SCs, but not HCs, are interconnected by gap junctions that are thought to play a role in fluid homeostasis in the cochlea and/or intercellular signalling. Gap junctions are mediated by special proteins (connexins). The majority of hereditary hearing disorders, including age-related hearing-loss (ARHL) are associated with defects in, or lack of expression of, connexions 26 (Cx26) and Cx30. Cx26 and Cx30, which interconnect DCs and PCs, have been recently implicated in the transmission of forces within the OC. We wish to discover how they might do this and how a specific Cx30 mutation can rescue hearing loss in a mouse strain with severe ARHL.