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.
Project description:Duchenne muscular dystrophy (DMD) is a debilitating and typically fatal X-linked progressive neuromuscular disorder that results in progressive muscle degeneration aggravated by sterile inflammation. The P2RX7 purinoceptor is an extracellular ATP-gated ion channel expressed in immune cells, and has been targeted in treatment of infectious and inflammatory diseases. In particular, P2xr7 receptor abnormalities have been demonstrated in mdx dystrophic mice, a model for DMD lacking expression of the full length dystrophin transcript through a single point mutation in exon 23. Here, we looked at the differential effects in gene expression regulation in whole muscle in dystrophic mdx mice with or without ablation of the P2rx7 purinoceptor.
Project description:We applied whole-genome single nucleotide polymorphism (SNP) arrays to define a comprehensive genetic profile of 23 esophageal adenocarcinoma (EAC) primary tumor biopsies based on loss of heterozygosity (LOH) and DNA copy number changes. Alterations were common, averaging 97 (range 23-208) per tumor. LOH and gains averaged 33 (range 3-83) and 31 (range 11-73) per tumor, respectively. Copy neutral LOH events averaged 27 (range 7-57) per EAC. We noted 126 homozygous deletions (HDs) across the EAC panel (range 0-11 in individual tumors). Frequent HDs within FHIT (17/23), WWOX (8/23) and DMD (6/23) suggest a role for common fragile sites or genomic instability in EAC etiology. HDs were also noted for known tumor suppressor genes (TSGs) including: CDKN2A, CDKN2B, SMAD4 and GALR1, and identified PDE4D and MGC48628 as potentially novel TSGs. All tumors showed LOH for most of chromosome 17p, suggesting that TSGs other than TP53 maybe targeted. Frequent gains were noted around MYC (13/23), BCL9 (12/23), CTAGE1 (14/23) and ZNF217 (12/23). Thus, we have confirmed previous reports indicating frequent changes to FHIT, CDKN2A, TP53 and MYC in EAC and identified additional genes of interest. Meta analysis of previous genome-wide EAC studies together with the data presented here, highlighted consistent regions of gain on 8q, 18q and 20q, and multiple LOH regions on 4q, 5q, 17p and 18q, suggesting that more than one gene may be targeted on each of these chromosome arms. The focal gains and deletions documented here are a step towards identifying the key genes involved in EAC development. Keywords: High Density SNP array Here we use Illumina 317K whole-genome single-nucleotide polymorphism arrays to define a comprehensive allelotype of melanoma based on loss of heterozygosity (LOH) and copy number changes in a panel of 23 esophageal adenocarcinoma (EAC) primary tumor biopsies. Each EAC was paired to normal squamous biopsy from 40328 (GSM266078) to generate the log_R_ratio.
Project description:Duchenne muscular dystrophy (DMD) is a rare and devastating genetic disorder, whose management is still a major challenge, despite progress in genetic and pharmacological disease-modifying treatments have been made. Mitochondrial dysfunctions contribute to DMD, however, there are no effective mitochondrial therapies for DMD. SIRT1 is a NAD+-dependent class III histone deacetylase that controls several key processes and whose impairment is involved in determining mitochondrial dysfunction in DMD. In addition to well-known resveratrol, other potent selective activators of SIRT1 exist, with better pharmacokinetics properties. Among these, SRT2104 is the most promising and advanced in clinical studies. Here we evaluate the impact of SRT2104 in reshaping muscle proteome and acetylome profiles, highlighting the drug as an attractive exercise mimetic for the treatment of DMD. Overall, our data suggest SRT2104 as a possible therapeutic candidate to successfully counteract the progression of the dystrophic phenotype in DMD.
Project description: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.
Project description: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.