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Biochemical Genetics Apr 2024Emanuel syndrome is a rare autosomal disorder characterized by microcephaly, heart defects, cleft palate and developmental delay. However, there is a lack of specific...
Emanuel syndrome is a rare autosomal disorder characterized by microcephaly, heart defects, cleft palate and developmental delay. However, there is a lack of specific prenatal screening for Emanuel syndrome. To screen for early diagnostic marker genes in fetuses with karyotype+der[22]t(11;22)(q23;q11) of Emanuel syndrome. Transcriptome sequencing and clinical trait data of t(11;22)(q23;q11) translocation samples were screened from the GEO database. The differentially expressed genes (DEGs) were screened by principal component analysis of gene expression by R package, and intersections were taken with balanced and unbalanced DEGs. Then, the correlation with clinical traits was determined by WGCNA analysis, GO and KEGG enrichment analysis, and then univariate Cox analysis and Lasso analysis were performed to obtain the key genes. The core regulatory genes were obtained after protein-protein interaction (PPI) network analysis. A total of 50 DEGs were obtained after differential analysis. WGCNA analysis showed that DEG was associated with the chromosomal imbalance and age module. GO and KEGG enrichment analyses showed candidate genes were associated with exocytic vesicle membrane, synaptic vesicle membranes, glycoprotein complex, dystrophin-associated glycoprotein complex and malaria. COX and Lasso analyses yielded 5 hub genes, including ZBED9, RGS20, SGCB, ETV5, and ZAP70. The results of PPI identified the key regulatory gene associated with chromosomal imbalance as the ZAP70 gene. ZAP70 may be a key gene for early diagnosis of Emanuel syndrome in fetuses with+der[22]t(11;22)(q23;q11) karyotype.
PubMed: 38687434
DOI: 10.1007/s10528-024-10808-3 -
Biomedicines Apr 2024Casimersen (AMONDYS 45) is an antisense oligonucleotide of the phosphorodiamidate morpholino oligomer subclass developed by Sarepta therapeutics. It was approved by the... (Review)
Review
Casimersen (AMONDYS 45) is an antisense oligonucleotide of the phosphorodiamidate morpholino oligomer subclass developed by Sarepta therapeutics. It was approved by the Food and Drug Administration (FDA) in February 2021 to treat Duchenne muscular dystrophy (DMD) in patients whose gene mutation is amenable to exon 45 skipping. Administered intravenously, casimersen binds to the pre-mRNA of the gene to skip a mutated region of an exon, thereby producing an internally truncated yet functional dystrophin protein in DMD patients. This is essential in maintaining the structure of a myocyte membrane. While casimersen is currently continuing in phase III of clinical trials in various countries, it was granted approval by the FDA under the accelerated approval program due to its observed increase in dystrophin production. This article discusses the pathophysiology of DMD, summarizes available treatments thus far, and provides a full drug review of casimersen (AMONDYS 45).
PubMed: 38672266
DOI: 10.3390/biomedicines12040912 -
Skeletal Muscle Apr 2024Duchenne muscular dystrophy (DMD) is associated with impaired muscle regeneration, progressive muscle weakness, damage, and wasting. While the cause of DMD is an...
BACKGROUND
Duchenne muscular dystrophy (DMD) is associated with impaired muscle regeneration, progressive muscle weakness, damage, and wasting. While the cause of DMD is an X-linked loss of function mutation in the gene encoding dystrophin, the exact mechanisms that perpetuate the disease progression are unknown. Our laboratory has demonstrated that pannexin 1 (Panx1 in rodents; PANX1 in humans) is critical for the development, strength, and regeneration of male skeletal muscle. In normal skeletal muscle, Panx1 is part of a multiprotein complex with dystrophin. We and others have previously shown that Panx1 levels and channel activity are dysregulated in various mouse models of DMD.
METHODS
We utilized myoblast cell lines derived from DMD patients to assess PANX1 expression and function. To investigate how Panx1 dysregulation contributes to DMD, we generated a dystrophic (mdx) mouse model that lacks Panx1 (Panx1/mdx). In depth characterization of this model included histological analysis, as well as locomotor, and physiological tests such as muscle force and grip strength assessments.
RESULTS
Here, we demonstrate that PANX1 levels and channel function are reduced in patient-derived DMD myoblast cell lines. Panx1/mdx mice have a significantly reduced lifespan, and decreased body weight due to lean mass loss. Their tibialis anterior were more affected than their soleus muscles and displayed reduced mass, myofiber loss, increased centrally nucleated myofibers, and a lower number of muscle stem cells compared to that of Panx1/mdx mice. These detrimental effects were associated with muscle and locomotor functional impairments. In vitro, PANX1 overexpression in patient-derived DMD myoblasts improved their differentiation and fusion.
CONCLUSIONS
Collectively, our findings suggest that PANX1/Panx1 dysregulation in DMD exacerbates several aspects of the disease. Moreover, our results suggest a potential therapeutic benefit to increasing PANX1 levels in dystrophic muscles.
Topics: Animals; Muscular Dystrophy, Duchenne; Connexins; Mice, Inbred mdx; Muscle, Skeletal; Male; Nerve Tissue Proteins; Humans; Mice; Myoblasts; Cell Line; Muscle Strength; Disease Models, Animal; Mice, Inbred C57BL; Mice, Knockout
PubMed: 38671506
DOI: 10.1186/s13395-024-00340-8 -
Cells Apr 2024A deficiency in the shortest dystrophin-gene product, Dp71, is a pivotal aggravating factor for intellectual disabilities in Duchenne muscular dystrophy (DMD). Recent...
A deficiency in the shortest dystrophin-gene product, Dp71, is a pivotal aggravating factor for intellectual disabilities in Duchenne muscular dystrophy (DMD). Recent advances in preclinical research have achieved some success in compensating both muscle and brain dysfunctions associated with DMD, notably using exon skipping strategies. However, this has not been studied for distal mutations in the gene leading to Dp71 loss. In this study, we aimed to restore brain Dp71 expression in the Dp71-null transgenic mouse using an adeno-associated virus (AAV) administrated either by intracardiac injections at P4 (ICP4) or by bilateral intracerebroventricular (ICV) injections in adults. ICP4 delivery of the AAV9-Dp71 vector enabled the expression of 2 to 14% of brain Dp71, while ICV delivery enabled the overexpression of Dp71 in the hippocampus and cortex of adult mice, with anecdotal expression in the cerebellum. The restoration of Dp71 was mostly located in the glial endfeet that surround capillaries, and it was associated with partial localization of Dp71-associated proteins, α1-syntrophin and AQP4 water channels, suggesting proper restoration of a scaffold of proteins involved in blood-brain barrier function and water homeostasis. However, this did not result in significant improvements in behavioral disturbances displayed by Dp71-null mice. The potential and limitations of this AAV-mediated strategy are discussed. This proof-of-concept study identifies key molecular markers to estimate the efficiencies of Dp71 rescue strategies and opens new avenues for enhancing gene therapy targeting cognitive disorders associated with a subgroup of severely affected DMD patients.
Topics: Animals; Male; Mice; Aquaporin 4; Behavior, Animal; Brain; Calcium-Binding Proteins; Dependovirus; Disease Models, Animal; Dystrophin; Genetic Therapy; Genetic Vectors; Membrane Proteins; Mice, Inbred C57BL; Mice, Knockout; Muscle Proteins; Muscular Dystrophy, Duchenne
PubMed: 38667332
DOI: 10.3390/cells13080718 -
Journal of Controlled Release :... Jun 2024Double pH-responsive xenopeptide carriers containing succinoyl tetraethylene pentamine (Stp) and lipo amino fatty acids (LAFs) were evaluated for CRISPR/Cas9 based...
Double pH-responsive xenopeptide carriers containing succinoyl tetraethylene pentamine (Stp) and lipo amino fatty acids (LAFs) were evaluated for CRISPR/Cas9 based genome editing. Different carrier topologies, variation of LAF/Stp ratios and LAF types as Cas9 mRNA/sgRNA polyplexes were screened in three different reporter cell lines using three different genomic targets (Pcsk9, eGFP, mdx exon 23). One U-shaped and three bundle (B2)-shaped lipo-xenopeptides exhibiting remarkable efficiencies were identified. Genome editing potency of top carriers were observed at sub-nanomolar EC concentrations of 0.4 nM sgRNA and 0.1 nM sgRNA for the top U-shape and top B2 carriers, respectively, even after incubation in full (≥ 90%) serum. Polyplexes co-delivering Cas9 mRNA/sgRNA with a single stranded DNA template for homology directed gene editing resulted in up to 38% conversion of eGFP to BFP in reporter cells. Top carriers were formulated as polyplexes or lipid nanoparticles (LNPs) for subsequent in vivo administration. Formulations displayed long-term physicochemical and functional stability upon storage at 4 °C. Importantly, intravenous administration of polyplexes or LNPs mediated in vivo editing of the dystrophin gene, triggering mRNA exon 23 splicing modulation in dystrophin-expressing cardiac muscle, skeletal muscle and brain tissue.
Topics: Gene Editing; Animals; CRISPR-Cas Systems; Humans; Nanoparticles; Lipids; Mice, Inbred mdx; Cell Line; Mice, Inbred C57BL; Male; Dystrophin; Mice
PubMed: 38663751
DOI: 10.1016/j.jconrel.2024.04.037 -
Physiological Reports Apr 2024Duchenne muscular dystrophy (DMD) is an X-linked recessive myopathy due to mutations in the dystrophin gene. Diaphragmatic weakness in DMD causes hypoventilation and...
Duchenne muscular dystrophy (DMD) is an X-linked recessive myopathy due to mutations in the dystrophin gene. Diaphragmatic weakness in DMD causes hypoventilation and elevated afterload on the right ventricle (RV). Thus, RV dysfunction in DMD develops early in disease progression. Herein, we deliver a 30-min sustained RV preload/afterload challenge to isolated hearts of wild-type (Wt) and dystrophic (Dmd) mice at both young (2-6 month) and middle-age (8-12 month) to test the hypothesis that the dystrophic RV is susceptible to dysfunction with elevated load. Young dystrophic hearts exhibited greater pressure development than wild type under baseline (Langendorff) conditions, but following RV challenge exhibited similar contractile function as wild type. Following the RV challenge, young dystrophic hearts had an increased incidence of premature ventricular contractions (PVCs) compared to wild type. Hearts of middle-aged wild-type and dystrophic mice had similar contractile function during baseline conditions. After RV challenge, hearts of middle-aged dystrophic mice had severe RV dysfunction and arrhythmias, including ventricular tachycardia. Following the RV load challenge, dystrophic hearts had greater lactate dehydrogenase (LDH) release than wild-type mice indicative of damage. Our data indicate age-dependent changes in RV function with load in dystrophin deficiency, highlighting the need to avoid sustained RV load to forestall dysfunction and arrhythmia.
Topics: Animals; Male; Dystrophin; Mice; Myocardial Contraction; Arrhythmias, Cardiac; Ventricular Dysfunction, Right; Muscular Dystrophy, Duchenne; Mice, Inbred mdx; Mice, Inbred C57BL
PubMed: 38658324
DOI: 10.14814/phy2.16004 -
Neuromuscular Disorders : NMD Jun 2024Duchenne muscular dystrophy is a neuromuscular disease caused by DMD gene mutations that result in an absence of functional dystrophin protein. Patients with Duchenne...
Duchenne muscular dystrophy is a neuromuscular disease caused by DMD gene mutations that result in an absence of functional dystrophin protein. Patients with Duchenne experience progressive muscle weakness, are typically wheelchair dependent by their early teens, and develop respiratory and cardiac complications that lead to death in their twenties or thirties. Becker muscular dystrophy is also caused by DMD gene mutations, but symptoms are less severe and progression is slower compared with Duchenne. We describe a case study of a patient with Becker muscular dystrophy who was still ambulant at age 61 years and had a milder phenotype than Duchenne, despite 46% of his DMD gene being missing. His affected relatives had similarly mild phenotypes and clinical courses. These data guided the understanding of the criticality of various regions of dystrophin and informed the development of micro-dystrophin constructs to compensate for the absence of functional dystrophin in Duchenne.
Topics: Humans; Muscular Dystrophy, Duchenne; Dystrophin; Male; Middle Aged; Phenotype; Follow-Up Studies; Pedigree
PubMed: 38653179
DOI: 10.1016/j.nmd.2024.04.004 -
Neurogastroenterology and Motility Apr 2024Duchenne's muscular dystrophy (DMD) is a severe type of hereditary, neuromuscular disorder caused by a mutation in the dystrophin gene resulting in the absence or... (Review)
Review
BACKGROUND
Duchenne's muscular dystrophy (DMD) is a severe type of hereditary, neuromuscular disorder caused by a mutation in the dystrophin gene resulting in the absence or production of truncated dystrophin protein. Conventionally, clinical descriptions of the disorder focus principally on striated muscle defects; however, DMD manifestations involving gastrointestinal (GI) smooth muscle have been reported, even if not rigorously studied.
PURPOSE
The objective of the present review is to offer a comprehensive perspective on the existing knowledge concerning GI manifestations in DMD, focusing the attention on evidence in DMD patients and mdx mice. This includes an assessment of symptomatology, etiological pathways, and potential corrective approaches. This paper could provide helpful information about DMD gastrointestinal implications that could serve as a valuable orientation for prospective research endeavors in this field. This manuscript emphasizes the effectiveness of mdx mice, a DMD animal model, in unraveling mechanistic insights and exploring the pathological alterations in the GI tract. The gastrointestinal consequences evident in patients with DMD and the mdx mice models are a significant area of focus for researchers. The exploration of this area in depth could facilitate the development of more efficient therapeutic approaches and improve the well-being of individuals impacted by the condition.
PubMed: 38651673
DOI: 10.1111/nmo.14804 -
American Journal of Physiology. Cell... Jul 2024The dystrophin gene () is recognized for its significance in Duchenne muscular dystrophy (DMD), a lethal and progressive skeletal muscle disease. Some patients with DMD...
The dystrophin gene () is recognized for its significance in Duchenne muscular dystrophy (DMD), a lethal and progressive skeletal muscle disease. Some patients with DMD and model mice with muscular dystrophy (mdx) spontaneously develop various types of tumors, among which rhabdomyosarcoma (RMS) is the most prominent. By contrast, spindle cell sarcoma (SCS) has rarely been reported in patients or mdx mice. In this study, we aimed to use metabolomics to better understand the rarity of SCS development in mdx mice. Gas chromatography-mass spectrometry was used to compare the metabolic profiles of spontaneously developed SCS and RMS tumors from mdx mice, and metabolite supplementation assays and silencing experiments were used to assess the effects of metabolic differences in SCS tumor-derived cells. The levels of 75 metabolites exhibited differences between RMS and SCS, 25 of which were significantly altered. Further characterization revealed downregulation of nonessential amino acids, including alanine, in SCS tumors. Alanine supplementation enhanced the growth, epithelial mesenchymal transition, and invasion of SCS cells. Reduction of intracellular alanine via knockdown of the alanine transporter Slc1a5 reduced the growth of SCS cells. Lower metabolite secretion and reduced proliferation of SCS tumors may explain the lower detection rate of SCS in mdx mice. Targeting of alanine depletion pathways may have potential as a novel treatment strategy. To the best of our knowledge, SCS has rarely been identified in patients with DMD or mdx mice. We observed that RMS and SCS tumors that spontaneously developed from mdx mice with the same genetic background exhibited differences in metabolic secretion. We proposed that, in addition to dystrophin deficiency, the levels of secreted metabolites may play a role in the determination of tumor-type development in a deficient background.
Topics: Animals; Mice, Inbred mdx; Rhabdomyosarcoma; Mice; Sarcoma; Metabolomics; Cell Line, Tumor; Mice, Inbred C57BL; Disease Models, Animal; Cell Proliferation; Male; Muscular Dystrophy, Duchenne; Epithelial-Mesenchymal Transition; Amino Acid Transport System ASC
PubMed: 38646787
DOI: 10.1152/ajpcell.00523.2023 -
Zhonghua Fu Chan Ke Za Zhi Apr 2024To evaluate the diagnostic efficiency of copy number variation sequencing (CNV-seq) to detect the deletion or duplication of DMD gene in prenatal diagnosis. A...
To evaluate the diagnostic efficiency of copy number variation sequencing (CNV-seq) to detect the deletion or duplication of DMD gene in prenatal diagnosis. A retrospective analysis was carried out on the CNV-seq results of 34 544 fetuses diagnosed in the First People's Hospital of Yunnan Province from January 2018 to July 2023. A total of 156 cases of fetuses were collected, including Group 1:125 cases with family history of Duchenne muscular dystrophy or Becker muscular dystrophy (DMD/BMD), and Group 2:31 cases with no family history but a DMD gene deletion or duplication was detected unexpectedly by CNV-seq. Multiplex ligation-dependent probe amplification (MLPA) was used as a standard method to detect the deletion or duplication. Consistency test was carried out basing on the results of CNV-seq and MLPA of all 156 cases. Comparing to MLPA, CNV-seq had a coincidence rate of 92.3% (144/156) for DMD gene deletion or duplication, with a sensitivity and positive predictive value of 88.2%, with a specificity and negative predictive value of 94.3%, a missed detection rate of 3.8%, and a Kappa value of 0.839. CNV-seq missed 4 cases with deletions and 2 with duplications due to involved fragments less than 100 Kb, among 20 cases of deletions and 6 cases of duplications detected by MLPA in Group 1. In Group 2, the deletions and duplications detected by CNV-seq were 42% (13/31) and 58% (18/31), respectively, in which the percentage of duplication was higher than that in Group 1. Among those 18 cases with duplications, 3 cases with duplication locating in exon 42~67 were likely pathogenic; while 9 cases with duplication covering the 5' or 3' end of the DMD gene, containing exon 1 or 79 and with only one breakpoint within the gene, along with the last 6 cases with duplications locating at chrX: 32650635_32910000 detected only by CNV-seq, which might be judged as variants of uncertain significance. CNV-seq has a good efficiency to detect fetal DMD gene deletion or duplication in prenatal diagnosis, while a further verification test by MLPA is recommended. The duplications on chrX: 32650635_32910000, 5' or 3' end of DMD gene detected by CNV-seq should be carefully verified and assessed because those variants appear to be nonpathogenic polymorphisms.
Topics: Humans; DNA Copy Number Variations; Prenatal Diagnosis; Pregnancy; Female; Muscular Dystrophy, Duchenne; Retrospective Studies; Gene Duplication; Gene Deletion; Sensitivity and Specificity; Dystrophin; Fetus; Multiplex Polymerase Chain Reaction
PubMed: 38644274
DOI: 10.3760/cma.j.cn112141-20230919-00107