Project description:The Christchurch mutation (R136S) on the APOE3 (E3S/S) gene is associated with attenuation of tau load and cognitive decline despite the presence of a causal PSEN1 mutation and high levels of amyloid beta pathology in the carrier. However, the specific molecular mechanisms enabling the E3S/S mutation to mitigate tau-induced neurodegeneration remain unclear. Here, we replaced mouse ApoE with wild-type human E3 or E3S/S on a tauopathy background. The R136S mutation markedly decreased tau load and protected against tau-induced synaptic loss, myelin loss, and reduction in theta and gamma powers. Additionally, the R136S mutation reduced interferon response to tau pathology in both mouse and human microglia, suppressing cGAS-STING activation. Treating tauopathy mice carrying wild-type E3 with a cGAS inhibitor protected against tau-induced synaptic loss and induced similar transcriptomic alterations to those induced by the R136S mutation across brain cell types. Thus, suppression of microglial cGAS-STING-IFN pathway plays a central role in mediating the protective effects of R136S against tauopathy.
Project description:The Christchurch mutation (R136S) on the APOE3 (E3S/S) gene is associated with attenuation of tau load and cognitive decline despite the presence of a causal PSEN1 mutation and high levels of amyloid beta pathology in the carrier. However, the specific molecular mechanisms enabling the E3S/S mutation to mitigate tau-induced neurodegeneration remain unclear. Here, we replaced mouse ApoE with wild-type human E3 or E3S/S on a tauopathy background. The R136S mutation markedly decreased tau load and protected against tau-induced synaptic loss, myelin loss, and reduction in theta and gamma powers. Additionally, the R136S mutation reduced interferon response to tau pathology in both mouse and human microglia, suppressing cGAS-STING activation. Treating tauopathy mice carrying wild-type E3 with a cGAS inhibitor protected against tau-induced synaptic loss and induced similar transcriptomic alterations to those induced by the R136S mutation across brain cell types. Thus, suppression of microglial cGAS-STING-IFN pathway plays a central role in mediating the protective effects of R136S against tauopathy.
Project description:Autosomal recessive congenital ichthyosis (ARCI) refers to a group of rare, highly debilitating skin disorders which significantly impair patients’ quality of life and lack any effective treatment options. Here, we report clinically-relevant in situ correction of the most common ARCI-causing mutation TGM1 c.877-2A>G, a splice-site aberration, in human disease models. Targeted skin barrier modulation followed by topical application of the cytosine base editor eTD packaged into lipid nanoparticles yielded functional restoration of ~30% of wild-type transglutaminase 1 activity in skin tissue. Toxicity studies and comprehensive off-target analysis demonstrated an excellent safety profile even after repeated application, without systemic distribution of the lipid nanoparticles or the genetic cargo as determined via highly-sensitive methods including DESI metabolic imaging. This study presents comprehensive preclinical data on the feasibility of in situ gene correction of genodermatoses-causing mutations showcasing its therapeutic potential and paving the way for curative next-generation treatments for severe genetic skin diseases.
Project description:Restrictive cardiomyopathy (RCM) is a severe cardiac disorder characterized by impaired ventricular filling and diastolic dysfunction, with mutations in sarcomeric proteins representing major causative factors. Mutations of TNNI3 gene (e.g. p.R192H) constitute major genetic causes of RCM, particularly affecting pediatric patients and being associated with poor prognosis. Here, we demonstrate that adenine base editor (ABE) is able effectively correct RCM-causing mutation and alleviate RCM in a murine model. We first developed a novel murine model harboring the Tnni3R193H mutation that recapitulates the hallmark features of human RCM. Importantly, targeted delivery of ABE via adeno-associated virus (AAV) achieved efficient and precise correction of the Tnni3R193H mutation in adult RCM mice, leading to significant improvement of cardiac functions. Our findings establish base editing as a therapeutic strategy for RCM and highlight its broader potential for treating genetic cardiomyopathies in clinical settings.
Project description:Pathogenic variants in MYBPC3 (myosin-binding protein C3) are the leading cause of genetic hypertrophic cardiomyopathy (HCM). Currently, there is no specific and effective treatment for this disease. Base editing is an emerging modality for treating monogenic diseases; however, its effect on MYBPC3 cardiomyopathy remains unexplored. Mybpc3-R946X/R946X mice developed early-onset left ventricular hypertrophy, systolic dysfunction, ventricular dilatation, and arrythmias. SpRY-ABEmax inefficiently corrected the Mybpc3-R946X mutation. In contrast, SpRY-ABE8e increased the efficiency by 3.6-fold and retained low level off-target editing. In vivo administration of SpRY-ABE8e efficiently corrected Mybpc3-R946X mutation in cardiomyocytes and prevented heart function decline, hypertrophic cardiomyopathy, and ventricular dysfunction. The therapeutic efficacy of SpRY-ABE8e-mediated gene correction surmounted AAV-mediated Mybpc3 gene replacement.Our study unveiled the immense potential of base editing to treat fatal inherited cardiomyopathies and opened a new avenue for the therapeutic managements of inherited cardiac diseases.
Project description:The most common form of genetic heart disease is hypertrophic cardiomyopathy (HCM), which is caused by mutations in cardiac sarcomeric genes and leads to abnormal heart muscle thickening. Complications of HCM include heart failure, arrhythmia, and sudden cardiac death. The dominant-negative c.1208 G>A (p.R403Q) mutation in b-myosin (MYH7) is a common and well-studied mutation that leads to increased cardiac contractility and HCM onset. Here we identify an adenine base editor (ABE) and single-guide RNA system that can efficiently correct this human pathogenic mutation with minimal off-target and bystander editing. We show that delivery of base editing components rescues pathological manifestations of HCM in iPSC-cardiomyocytes derived from HCM patients and in a humanized mouse model of HCM. Our findings demonstrate the use of base editing to treat inherited cardiac diseases and prompt the further development of ABE-based therapies to correct a variety of monogenic mutations causing cardiac disease.
Project description:Huntington's disease is a genetic disease caused by a single mutation. It is characterised by progressive movement, emotional and cognitive deficits. R6/2 transgenic mice carrying the Huntington's disease mutation have a progressive neurological phenotype, including deterioration in cognitive function. The mechanism underlying the cognitive deficits in R6/2 mice is unknown, but dysregulated gene expression, reduced neurotransmitter levels and abnormal synaptic function are present before the cognitive decline becomes pronounced. Our goal here was to ameliorate the cognitive phenotype in R6/2 mice using a combination drug therapy (tacrine, moclobemide and creatine) aimed boosting neurotransmitter levels in the brain. Treatment from 5 weeks of age prevented deterioration in two different cognitive tasks until at least 12 weeks. However, motor deterioration continued unabated. Microarray analysis of global gene expression revealed that many genes significantly up- or down-regulated in untreated R6/2 mice had returned towards normal levels after treatment. Thus dysregulated gene expression was reversed by the combination treatment in the R6/2 mice and probably underlies the observed improvements in cognitive function. Our study shows that cognitive decline caused by a genetic mutation can be slowed by a combination drug treatment, and gives hope that cognitive symptoms in HD can be treated.
Project description:In this study, we particularly focused on short ncRNA expression profiling of three, ten and twenty month old triple transgenic mouse model for Alzheimers disease (Oddo et al.; 2003;Neuron). These mice harbor presenilin PS1(M146V), APP(Swedish) and tau(P301L) mutations and develop beta-amyloid plaques and at later stages also a tau pathology. Controls are age matched B6129SF2/J mice.
Project description:TMEM106B is a risk modifier for a growing list of age-associated dementias including Alzheimer's and frontotemporal dementia, yet its function remains elusive. Two key questions that emerge from past work are whether the conservative T185S coding variant found in the minor haplotype contributes to protection, and whether the presence of TMEM106B is helpful or harmful in the context of disease. Here we address both issues while extending the testbed for study of TMEM106B from models of TDP to tauopathy. We show that TMEM106B deletion accelerates cognitive decline, hindlimb paralysis, neuropathology, and neurodegeneration. TMEM106B deletion also increases transcriptional overlap with human AD, making it a better model of disease than tau alone. In contrast, the coding variant protects against tau-associated cognitive decline, neurodegeneration, and paralysis without affecting tau pathology. Our findings show that the coding variant contributes to neuroprotection and suggest that TMEM106B is a critical safeguard against tau aggregation.