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Project description:Dominant pathogenic variants encoding amino acid substitutions in cardiac myosin heavy chain cause hypertrophic cardiomyopathy (HCM), a currently incurable disorder that increases risk for stroke, heart failure, and sudden cardiac death. We assessed the efficacy of two different genetic therapies, an adenine base editor (ABE8e) and a potent Cas9 nuclease delivered by AAV9, to prevent disease in mice carrying the heterozygous HCM pathogenic variant myosin R403Q. One dose of dual AAV9 vectors, each carrying one half of RNA-guided ABE8e, corrected the pathogenic variant in ≥70% of ventricular cardiomyocytes and maintained durable, normal cardiac structure and function. An additional dose provided more global editing especially in the atria but also increased bystander editing. AAV9 delivery of RNA-guided Cas9 nuclease effectively inactivated the pathogenic allele, albeit with dose-dependent toxicities, necessitating a narrow therapeutic window to maintain health. These preclinical studies demonstrate considerable potential for single-dose genetic therapies to correct or silence pathogenic variants and prevent the development of HCM.
2022-12-13 | GSE220811 | GEO
Project description:We assessed genome editing strategies to treat cardiomyopathy in mice including one or two doses of ABE8e, or one low, medium, or high dose of SaCas9 nuclease We conducted RNA analysis and genomic DNA analysis at the target region and transcriptome-wide analysis to assess cellular phenotypes
2022-12-13 | GSE220850 | GEO
Project description:Dominant pathogenic variants encoding amino acid substitutions in cardiac myosin heavy chain cause hypertrophic cardiomyopathy (HCM), a currently incurable disorder that increases risk for stroke, heart failure, and sudden cardiac death. We assessed the efficacy of two different genetic therapies, an adenine base editor (ABE8e) and a potent Cas9 nuclease delivered by AAV9, to prevent disease in mice carrying the heterozygous HCM pathogenic variant myosin R403Q. One dose of dual AAV9 vectors, each carrying one half of RNA-guided ABE8e, corrected the pathogenic variant in ≥70% of ventricular cardiomyocytes and maintained durable, normal cardiac structure and function. An additional dose provided more global editing especially in the atria but also increased bystander editing. AAV9 delivery of RNA-guided Cas9 nuclease effectively inactivated the pathogenic allele, albeit with dose-dependent toxicities, necessitating a narrow therapeutic window to maintain health. These preclinical studies demonstrate considerable potential for single-dose genetic therapies to correct or silence pathogenic variants and prevent the development of HCM.
2022-12-13 | GSE220808 | GEO
Project description:Dominant pathogenic variants encoding amino acid substitutions in cardiac myosin heavy chain cause hypertrophic cardiomyopathy (HCM), a currently incurable disorder that increases risk for stroke, heart failure, and sudden cardiac death. We assessed the efficacy of two different genetic therapies, an adenine base editor (ABE8e) and a potent Cas9 nuclease delivered by AAV9, to prevent disease in mice carrying the heterozygous HCM pathogenic variant myosin R403Q. One dose of dual AAV9 vectors, each carrying one half of RNA-guided ABE8e, corrected the pathogenic variant in ≥70% of ventricular cardiomyocytes and maintained durable, normal cardiac structure and function. An additional dose provided more global editing especially in the atria but also increased bystander editing. AAV9 delivery of RNA-guided Cas9 nuclease effectively inactivated the pathogenic allele, albeit with dose-dependent toxicities, necessitating a narrow therapeutic window to maintain health. These preclinical studies demonstrate considerable potential for single-dose genetic therapies to correct or silence pathogenic variants and prevent the development of HCM.
2022-12-13 | GSE220517 | GEO
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.
2024-04-04 | GSE239872 | GEO
Project description:AimsIncreased myofilament contractility is recognized as a crucial factor in the pathogenesis of hypertrophic cardiomyopathy (HCM). Direct myofilament desensitization might be beneficial in preventing HCM disease progression. Here, we tested whether the small molecule fropofol prevents HCM phenotype expression and disease progression by directly depressing myofilament force development.Methods and resultsForce, intracellular Ca2+, and steady-state activation were determined in isolated trabecular muscles from wild-type (WT) and transgenic HCM mice with heterozygous human α-myosin heavy chain R403Q mutation (αMHC 403/+). αMHC 403/+ HCM mice were treated continuously with fropofol by intraperitoneal infusion for 12 weeks. Heart tissue was analysed with histology and real-time PCR of prohypertrophic and profibrotic genes. Fropofol decreased force in a concentration-dependent manner without significantly altering [Ca2+]i in isolated muscles from both WT and αMHC 403/+ HCM mouse hearts. Fropofol also depressed maximal Ca2+-activated force and increased the [Ca2+]i required for 50% activation during steady-state activation. In whole-animal studies, chronic intra-abdominal administration of fropofol prevented hypertrophy development and diastolic dysfunction. Chronic fropofol treatment also led to attenuation of prohypertrophic and profibrotic gene expression, reductions in cell size, and decreases in tissue fibrosis.ConclusionsDirect inhibition of myofilament contraction by fropofol prevents HCM disease phenotypic expression and progression, suggesting that increased myofilament contractile force is the primary trigger for hypertrophy development and HCM disease progression.
| S-EPMC8453292 | biostudies-literature
Project description:AimsMutant protein aggregation (PA) cardiomyopathy (MPAC) is characterized by reductive stress (RS), PA (of chaperones and cytoskeletal components), and ventricular dysfunction in transgenic mice expressing human mutant CryAB (hmCryAB). Sustained activation of nuclear erythroid-2 like factor-2 (Nrf2) causes RS, which contributes to proteotoxic cardiac disease. The goals of this pre-clinical study were to (i) investigate whether disrupting Nrf2-antioxidant signalling prevents RS and rescues redox homeostasis in hearts expressing the mutant chaperone and (ii) elucidate mechanisms that could delay proteotoxic cardiac disease.Methods and resultsNon-transgenic (NTG), transgenic (TG) with MPAC and MPAC-TG:Nrf2-deficient (Nrf2-def) mice were used in this study. The effects of Nrf2 diminution (Nrf2±) on RS mediated MPAC in TG mice were assessed at 6-7 and 10 months of age. The diminution of Nrf2 prevented RS and prolonged the survival of TG mice (∼50 weeks) by an additional 20-25 weeks. The TG:Nrf2-def mice did not exhibit cardiac hypertrophy at even 60 weeks, while the MPAC-TG mice developed pathological hypertrophy and heart failure starting at 24-28 weeks of age. Aggregation of cardiac proteins was significantly reduced in TG:Nrf2-def when compared with TG mice at 7 months. Preventing RS and maintaining redox homeostasis in the TG:Nrf2-def mice ameliorated PA, leading to decreased ubiquitination of proteins.ConclusionNrf2 deficiency rescues redox homeostasis, which reduces aggregation of mutant proteins, thereby delaying the proteotoxic pathological cardiac remodelling caused by RS and toxic protein aggregates.
| S-EPMC3778956 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-12-20 | GSE226209 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-06-30 | GSE216250 | GEO
Project description:As an alternative and complementary approach to Cas9-based genome editing, Cas12a has not been widely used in mammalian cells largely due to its strict requirement for the TTTV protospacer adjacent motif (PAM) sequence. Here, we report that Mb3Cas12a (Moraxella bovoculi AAX11_00205) can efficiently edit the mouse genome based on the TTV PAM sequence with minimal numbers of large on-target deletions or insertions. When TTTV PAM sequence-targeting CRISPR (cr)RNAs of 23 nt spacers are used, >70% of the founders obtained are edited. Moreover, the use of Mb3Cas12a tagged to monomeric streptavidin (mSA) in conjunction with biotinylated DNA donor template leads to high knock-in efficiency in two-cell mouse embryos, with 40% of founders obtained containing the desired knock-in sequences.
| S-EPMC7240296 | biostudies-literature