Dataset Information

Inhibiting EZH2 complements steroid effects in Duchenne muscular dystrophy [mouse]

ABSTRACT: Duchenne muscular dystrophy (DMD) is a devastating X-linked disorder caused by mutations in the dystrophin gene. Despite recent advances in understanding the disease etiology and applying emerging treatment methodologies, glucocorticoid derivatives remain the only general therapeutic option that can slow disease development. However, the precise molecular mechanism of glucocorticoid action remains unclear, and there is still need for additional remedies to complement the treatment. Here, using single-nucleus RNA-sequencing and spatial transcriptome analyses of human and mouse muscles, we investigated pathogenic features in DMD patients and palliative effects of glucocorticoids. Our approach further illuminated the importance of proliferating satellite cells, and revealed increased activity of a signal transduction pathway involving EZH2 in the patient cells. Subsequent administration of EZH2 inhibitors to Dmd mutant mice resulted in improved muscle phenotype through maintaining the immune-suppressing effect but overriding the muscle weakness and fibrogenic effects exerted by glucocorticoids. Our analysis reveals pathogenic mechanisms that can be readily targeted by extant therapeutic options for DMD.

ORGANISM(S): Mus musculus

PROVIDER: GSE289040 | GEO | 2025/02/09

REPOSITORIES: GEO

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Project description:Absence of the dystrophin gene in Duchenne muscular dystrophy (DMD) results in the degeneration of skeletal and cardiac muscles. Owing to advances in respiratory medicine, cardiomyopathy has become a significant aspect of the disease. While CRISPR/Cas9 genome editing technology holds great potential as a novel therapeutic avenue for DMD, little is known about the efficacy of correction of DMD using the CRISPR/Cas9 system in mitigating the cardiomyopathy phenotype in DMD. To define the effects of CRISPR/Cas9 genome editing on structural, functional and transcriptional dysregulation in DMD-associated cardiomyopathy. We generated induced pluripotent stem cells (iPSCs) from a patient with a deletion of exon 44 of the DMD gene (ΔEx44) and his healthy brother. Here, we targeted exon 45 of the DMD gene by CRISPR/Cas9 genome editing to generate corrected DMD (cDMD) iPSC lines, wherein the DMD open reading frame was restored via reframing (RF) or exon skipping (ES). While DMD cardiomyocytes (CMs) demonstrated morphologic, structural and functional deficits compared to control CMs, CMs from both cDMD lines were similar to control CMs. Bulk RNA-sequencing of DMD CMs showed transcriptional dysregulation consistent with dilated cardiomyopathy, which was mitigated in cDMD CMs. We then corrected DMD CMs by adenoviral delivery of Cas9/gRNA and showed that postnatal correction of DMD CMs reduces their arrhythmogenic potential. Single-nucleus RNA-sequencing of hearts showed reduced transcriptional dysregulation in CMs and fibroblasts in corrected mice compared with DMD mice, consistent with reduced histopathologic changes.We show that CRISPR/Cas9-mediated correction of DMD ΔEx44 mitigates structural, functional and transcriptional dysregulation consistent with dilated cardiomyopathy irrespective of how the protein reading frame is restored. We show that these effects extend to postnatal editing in iPSC-CMs and mice. These findings provide key insights into the utility of genome editing as a novel therapeutic for DMD-associated cardiomyopathy.

Project description:Rationale – Absence of the dystrophin gene in Duchenne muscular dystrophy (DMD) results in the degeneration of skeletal and cardiac muscles. Owing to advances in respiratory medicine, cardiomyopathy has become a significant aspect of the disease. While CRISPR/Cas9 genome editing technology holds great potential as a novel therapeutic avenue for DMD, little is known about the efficacy of correction of DMD using the CRISPR/Cas9 system in mitigating the cardiomyopathy phenotype in DMD. Objective – To define the effects of CRISPR/Cas9 genome editing on structural, functional and transcriptional dysregulation in DMD-associated cardiomyopathy. Methods and Results – We generated induced pluripotent stem cells (iPSCs) from a patient with a deletion of exon 44 of the DMD gene (ΔEx44) and his healthy brother. Here, we targeted exon 45 of the DMD gene by CRISPR/Cas9 genome editing to generate corrected DMD (cDMD) iPSC lines, wherein the DMD open reading frame was restored via reframing (RF) or exon skipping (ES). While DMD cardiomyocytes (CMs) demonstrated morphologic, structural and functional deficits compared to control CMs, CMs from both cDMD lines were similar to control CMs. Bulk RNA-sequencing of DMD CMs showed transcriptional dysregulation consistent with dilated cardiomyopathy, which was mitigated in cDMD CMs. We then corrected DMD CMs by adenoviral delivery of Cas9/gRNA and showed that postnatal correction of DMD CMs reduces their arrhythmogenic potential. Single-nucleus RNA-sequencing of hearts showed reduced transcriptional dysregulation in CMs and fibroblasts in corrected mice compared with DMD mice, consistent with reduced histopathologic changes. Conclusions – We show that CRISPR/Cas9-mediated correction of DMD ΔEx44 mitigates structural, functional and transcriptional dysregulation consistent with dilated cardiomyopathy irrespective of how the protein reading frame is restored. We show that these effects extend to postnatal editing in iPSC-CMs and mice. These findings provide key insights into the utility of genome editing as a novel therapeutic for DMD-associated cardiomyopathy.