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Abdel-Hamid MS, Abouzaid MR, Mostafa MI, Ahmed NE. Papillon-Lefevre syndrome in twelve Egyptian patients: Five novel CTSC variants and functional characterization of a missense variant and its effect on splicing. Arch Oral Biol 2024; 158:105869. [PMID: 38104461 DOI: 10.1016/j.archoralbio.2023.105869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 12/19/2023]
Abstract
OBJECTIVES describing the clinical features of twelve Egyptian patients with Papillon-Lefever syndrome (PLS). Five novel mutations in the cathepsin C (CTSC) gene are introduced and the phenotype of the syndrome is expanded by the identification of new clinical features. DESIGN the clinical, oro-dental data of twelve Egyptian patients from seven unrelated families are described. Sequence analysis of the CTSC gene was performed to identify the causative mutaions. RESULTS Typical PLS features were presented in all patints but with variable severity. One patient showed atypical dental features including dental structural defect, minimal periodontitis, severe gingivitis, and delayed closure of root apices. Another patient presented with arachnodactyly, dystrophic nails, and buphthalmos in the right eye secondary to uncontrolled congenital glaucoma. Mutational analysis of CTSC gene revealed seven distinct homozygous variants including five novel ones: c.285_286delGT (p.Leu96GlufsTer2), c .302 G>C (p.Trp101Ser), c.622_628delCACAGTC (p.H208Efs*11), c.1331delinsAAAAA (p.G444Efs*4) and c .1343 G>A (p.Cys448Tyr). The previously reported missense variant c .757 G>A (p.Ala253Thr) was found in one patient. This variant is very close to the splice region and by functional studies, we proved that it results in exon skipping and early protein truncation (p.R214Sfs*46). CONCLUSION We report five novel CTSC variants and describe rare and unusual associated clinical and dental findings such as dental structural defects, delayed closure of root apices, and congenital glaucoma. Therefore, our results expand both the phenotypic and mutational spectrum of PLS.
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Affiliation(s)
- Mohamed S Abdel-Hamid
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Maha R Abouzaid
- Oro-dental Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Mostafa I Mostafa
- Oro-dental Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Nermeen Eb Ahmed
- Oro-dental Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt.
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Kimura H, Onozawa M, Hashiguchi J, Hidaka D, Kanaya M, Matsukawa T, Okada H, Kondo T, Matsuno Y, Teshima T. Hereditary thrombocythemia due to splicing donor site mutation of THPO in a Japanese family. Ann Hematol 2024; 103:89-96. [PMID: 37962621 DOI: 10.1007/s00277-023-05523-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023]
Abstract
Thrombopoietin (THPO) is an essential factor for platelet production. Hereditary thrombocythemia (HT) is caused by a germline mutation of THPO, MPL, or JAK2 and is inherited in an autosomal-dominant manner. We identified a Japanese family with HT due to a point mutation of the splicing donor site of the THPO gene (THPO c.13 + 1G > A). Bone marrow biopsy showed increased megakaryocytes mimicking essential thrombocythemia. One affected family member developed chronic myeloid leukemia. We cloned the mutation and developed mutated and wild type THPO expression vectors. Molecular analysis showed that the mutation causes an exon 3 skipping transcript of THPO that abrogates a suppressive untranslated upstream open reading frame. Although the transcript levels of THPO mRNA were comparable, mutated transcripts were more efficiently translated and THPO protein expression was significantly higher than that of the wild type.
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Affiliation(s)
- Hiroyuki Kimura
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan
| | - Masahiro Onozawa
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan.
| | - Junichi Hashiguchi
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan
| | - Daisuke Hidaka
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan
| | - Minoru Kanaya
- Blood Disorders Center, Aiiku Hospital, Sapporo, Japan
| | - Toshihiro Matsukawa
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan
| | - Hiromi Okada
- Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Japan
| | - Takeshi Kondo
- Blood Disorders Center, Aiiku Hospital, Sapporo, Japan
| | - Yoshihiro Matsuno
- Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Japan
| | - Takanori Teshima
- Department of Hematology, Hokkaido University Faculty of Medicine, Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, Japan
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Levchenko O, Panchuk I, Kochergin-Nikitsky K, Petrova I, Nagieva S, Pilkin M, Yakovlev I, Smirnikhina S, Deev R, Lavrov A. Unexpected extra exon skipping in the DYSF gene during restoring the reading frame by CRISPR/Cas9. Biosystems 2024; 235:105072. [PMID: 37944631 DOI: 10.1016/j.biosystems.2023.105072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023]
Abstract
The DYSF gene encoding dysferlin protein is one of the largest and has many transcripts. Pathogenic variants in the gene can lead to various types of myopathies, which makes it a good object for studying the events occurring in it during genome editing by the CRISPR/Cas method. In this study, we evaluated the possibility of permanent skipping of exons 3-4, and 26-27 which deletion does not violate the reading frame and allows to eliminate truncated variants within exons. Editing was performed with simultaneous transfection of two sgRNA- and sa/spCas9-containing plasmids on HEK293T cell cultures and healthy donor myoblasts. Skipping of exons 3-4 was performed by destroying the splicing acceptor sites, and exons 26-27 by cuts in the flanking exons with the corresponding deletion in the DNA. Some unexpected results were obtained, when exons 26-27 were skipped, exon 30 was also absent in the transcript, although it is not alternatively spliced and is normally present in all transcripts. This event indicates that DNA changes near splicing sites can affect adjacent exons and the whole gene. However, this fact requires further study.
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Affiliation(s)
- Olga Levchenko
- Research Centre for Medical Genetics, 115522, Moscow, Russia.
| | - Irina Panchuk
- Research Centre for Medical Genetics, 115522, Moscow, Russia
| | | | - Irina Petrova
- Research Centre for Medical Genetics, 115522, Moscow, Russia
| | - Sabina Nagieva
- Research Centre for Medical Genetics, 115522, Moscow, Russia
| | - Maxim Pilkin
- Research Centre for Medical Genetics, 115522, Moscow, Russia
| | | | | | - Roman Deev
- North-Western State Medical University named after I.I. Mechnikov, 191015, St. Petersburg, Russia
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Zhang Z, Zou X, Feng L, Huang Y, Chen F, Sun K, Song Y, Lv P, Gao X, Dong Y, Tian H. Splicing mutations in AMELX and ENAM cause amelogenesis imperfecta. BMC Oral Health 2023; 23:893. [PMID: 37985977 PMCID: PMC10662561 DOI: 10.1186/s12903-023-03508-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 10/08/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND Amelogenesis imperfecta (AI) is a developmental enamel defect affecting the structure of enamel, esthetic appearance, and the tooth masticatory function. Gene mutations are reported to be relevant to AI. However, the mechanism underlying AI caused by different mutations is still unclear. This study aimed to reveal the molecular pathogenesis in AI families with 2 novel pre-mRNA splicing mutations. METHODS Two Chinese families with AI were recruited. Whole-exome sequencing and Sanger sequencing were performed to identify mutations in candidate genes. Minigene splicing assays were performed to analyze the mutation effects on mRNA splicing alteration. Furthermore, three-dimensional structures of mutant proteins were predicted by AlphaFold2 to evaluate the detrimental effect. RESULTS The affected enamel in family 1 was thin, rough, and stained, which was diagnosed as hypoplastic-hypomature AI. Genomic analysis revealed a novel splicing mutation (NM_001142.2: c.570 + 1G > A) in the intron 6 of amelogenin (AMELX) gene in family 1, resulting in a partial intron 6 retention effect. The proband in family 2 exhibited a typical hypoplastic AI, and the splicing mutation (NM_031889.2: c.123 + 4 A > G) in the intron 4 of enamelin (ENAM) gene was observed in the proband and her father. This mutation led to exon 4 skipping. The predicted structures showed that there were obvious differences in the mutation proteins compared with wild type, leading to impaired function of mutant proteins. CONCLUSIONS In this study, we identified two new splicing mutations in AMELX and ENAM genes, which cause hypoplastic-hypomature and hypoplastic AI, respectively. These results expand the spectrum of genes causing AI and broaden our understanding of molecular genetic pathology of enamel formation.
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Affiliation(s)
- Zhenwei Zhang
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Xiaoying Zou
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Lin Feng
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Yu Huang
- Department of Medical Genetics, School of Basic Medical Sciences, Peking University Health and Science Center, Beijing, PR China
| | - Feng Chen
- Central Laboratory, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Kai Sun
- Department of Prosthodontics, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Yilin Song
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Ping Lv
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Xuejun Gao
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China
| | - Yanmei Dong
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China.
| | - Hua Tian
- Department of Cariology and Endodontology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, No. 22 Zhongguancun Nandajie, Haidian District, Beijing, 100081, PR China.
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Zhang C, Qiao F, Cheng Q, Luo C, Zhang Q, Hu P, Xu Z. A Novel Splice Site Mutation in the FBN2 Gene in a Chinese Family with Congenital Contractural Arachnodactyly. Biochem Genet 2023:10.1007/s10528-023-10550-2. [PMID: 37962692 DOI: 10.1007/s10528-023-10550-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 10/10/2023] [Indexed: 11/15/2023]
Abstract
Congenital contractural arachnodactyly (CCA) is a rare connective tissue disorder characterized by arachnodactyly, multiple joint contractures, progressive kyphoscoliosis, pectus deformity and abnormal crumpled ears. FBN2 is the only gene currently known to be associated with CCA. In this study, we report on a prenatal case presented with skeletal, cardiac and spinal malformations. And his father had elongated limbs, contractures of the proximal interphalangeal joints, high myopia and scoliosis. We conducted whole exome sequencing (WES) on the fetus-parental trio and a heterozygous variant (hg19 chr5:127,673,685, c.3598 + 4A > G, NM_001999.4) in intron 27 of the FBN2 gene was successfully identified, inherited from the father. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to evaluate the potential splicing effect of this variant, which confirmed that the variant caused a deletion of exon 27 (126 bp) by disrupting the splice-donor site and destroyed the 17th calcium-binding epidermal growth factor-like (cbEGF) domain. Our research not only finds the etiology of the disease in affected individuals and expands the mutation spectrum of FBN2 gene, but also provides genetic counseling and fertility guidance for this family.
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Affiliation(s)
- Cuiping Zhang
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China
| | - Fengchang Qiao
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China
| | - Qing Cheng
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China
| | - Chunyu Luo
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China
| | - Qinxin Zhang
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China
| | - Ping Hu
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China.
| | - Zhengfeng Xu
- Department of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, 210004, China.
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D'Ambrosio ES, Mendell JR. Evolving Therapeutic Options for the Treatment of Duchenne Muscular Dystrophy. Neurotherapeutics 2023; 20:1669-1681. [PMID: 37673849 PMCID: PMC10684843 DOI: 10.1007/s13311-023-01423-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 09/08/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most common childhood form of muscular dystrophy. It is caused by mutations in the DMD gene, leading to reduced or absent expression of the dystrophin protein. Clinically, this results in loss of ambulation, cardiomyopathy, respiratory failure, and eventually death. In the past decades, the use of corticosteroids has slowed down the disease progression. More recently, the development of genetically mediated therapies has emerged as the most promising treatment for DMD. These strategies include exon skipping with antisense oligonucleotides, gene replacement therapy with adeno-associated virus, and gene editing with CRISPR (clustered regularly interspaced short palindromic repeats) technology. In this review, we highlight the most up-to-date therapeutic progresses in the field, with emphasis on past and recent experiences, as well as the latest clinical results of DMD micro-dystrophin gene therapy. Additionally, we discuss the lessons learned along the way and the challenges encountered, all of which have helped advance the field, with the potential to finally alleviate such a devastating disease.
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Affiliation(s)
- Eleonora S D'Ambrosio
- Center for Gene Therapy, Department of Pediatrics, Abigail Wexner Research Institute, Nationwide Children's Hospital, Ohio State University, Columbus, OH, 43205, USA. eleonora.d'
| | - Jerry R Mendell
- Center for Gene Therapy, Department of Pediatrics, Abigail Wexner Research Institute, Nationwide Children's Hospital, Ohio State University, Columbus, OH, 43205, USA
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田 学, 陈 婵, 王 雄. [Tau Protein Induces Aberrant Alternative Splicing Changes in PS19 Transgenic Mice]. Sichuan Da Xue Xue Bao Yi Xue Ban 2023; 54:874-883. [PMID: 37866941 PMCID: PMC10579071 DOI: 10.12182/20230960501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Indexed: 10/24/2023]
Abstract
Objective To explore through big data analysis whether aberrant alternative splicing (AS) events precede tau P301S-induced neurodegenerative phenotype in 6-month-old PS19 mice. Methods The original sequencing files of the GSE182170 dataset was downloaded from the European Nucleotide Archive (ENA) database with axel, aligned to the reference genome of the ENSEMBL database by using STAR software, and common AS event analysis and visualization were performed with rMATS and rmats2sashimiplot R packages. RSEM software was utilized for gene transcript quantification, Deseq2, edgeR, and limma R packages were used for differential expression analysis, and clusterProfiler R package was applied for GO enrichment analysis. String and Cytoscape were used for protein-protein interaction (PPI) analysis. Gene expression correlation analysis was performed with ggcorrplot R package. AS events were validated using PCR followed by agarose electrophoresis. Results A total of 8 079 AS events were identified with rMATS and 117 significant AS events (ΔPSI>0.1, sequencing coverage >1) were selected eventually. The most frequent type of AS event was skipped exon (SE) (50.43%), followed by alternative 3' splice site (A3SS) and mutually exclusive exons (MXE). GO enrichment analysis revealed that synapse organization genes were aberrantly spliced in SE events and spliceosome genes were spliced in A3SS events. PPI and correlation analyses showed that the splicing factor Snrpn was significantly associated with the largest number of transcripts. Agarose electrophoresis confirmed the aberrant AS event of the Lrp8 gene in PS19 mice. Conclusion Dysregulated splicing factors may contribute to tau P301S-induced aberrant AS changes. The study also increases the understanding of the cycling of tau protein and splicing factors in tauopathies.
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Affiliation(s)
- 学文 田
- 华中科技大学同济医学院附属同济医院 检验科 (武汉 430030)Department of Clinical Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - 婵 陈
- 华中科技大学同济医学院附属同济医院 检验科 (武汉 430030)Department of Clinical Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - 雄 王
- 华中科技大学同济医学院附属同济医院 检验科 (武汉 430030)Department of Clinical Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Lu YT, Rejiepu B, Zhang D, Cai DC, Yang KQ, Tian T, Zhou XL, Fan P. Childhood-Onset Refractory Hypertension Results from Neurofibromatosis Type 1 Caused by a Splicing NF1 Mutation. Kidney Blood Press Res 2023; 48:568-577. [PMID: 37562365 PMCID: PMC10614435 DOI: 10.1159/000533144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023] Open
Abstract
INTRODUCTION Neurofibromatosis type 1 (NF-1) is caused by mutations in the NF1 gene that encodes neurofibromin, a negative regulator of RAS proto-oncogene. Approximately one-third of the reported pathogenic mutations in NF1 are splicing mutations, but most consequences are unclear. The objective of this study was to identify the pathogenicity of splicing mutation in a Chinese family with NF-1 and determine the effects of the pre-mRNA splicing mutation by in vitro functional analysis. METHODS Next-generation sequencing was used to screen candidate mutations. We performed a minigene splicing assay to determine the effect of the splicing mutation on NF1 expression, and three-dimensional structure models of neurofibromin were generated using SWISS-MODEL and PROCHECK methods, respectively. RESULTS A pathogenic splicing mutation c.479+1G>C in NF1 was found in the proband characterized by childhood-onset refractory hypertension. In vitro analysis demonstrated that c.479+1G>C mutation caused the skipping of exon 4, leading to a glutamine-to-valine substitution at position 97 in neurofibromin and an open reading frame shift terminating at codon 108. Protein modeling showed that several major domains were missing in the truncated neurofibromin protein. CONCLUSION The splicing mutation c.479+1G>C identified in a Chinese patient with NF-1 and childhood-onset refractory hypertension caused the skipping of exon 4 and a truncated protein. Our findings offer new evidence for the molecular diagnosis of NF-1.
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Affiliation(s)
- Yi-Ting Lu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Buweimairemu Rejiepu
- Department of Cardiac Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Di Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dong-Cheng Cai
- Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Tian
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Liu X, Shi X, Xin Q, Liu Z, Pan F, Qiao D, Chen M, Zhang Y, Guo W, Li C, Zhang Y, Shao L, Zhang R. Identified eleven exon variants in PKD1 and PKD2 genes that altered RNA splicing by minigene assay. BMC Genomics 2023; 24:407. [PMID: 37468838 PMCID: PMC10354997 DOI: 10.1186/s12864-023-09444-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 06/11/2023] [Indexed: 07/21/2023] Open
Abstract
BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenic multisystem disease caused primarily by mutations in the PKD1 gene or PKD2 gene. There is increasing evidence that some of these variants, which are described as missense, synonymous or nonsense mutations in the literature or databases, may be deleterious by affecting the pre-mRNA splicing process. RESULTS This study aimed to determine the effect of these PKD1 and PKD2 variants on exon splicing combined with predictive bioinformatics tools and minigene assay. As a result, among the 19 candidate single nucleotide alterations, 11 variants distributed in PKD1 (c.7866C > A, c.7960A > G, c.7979A > T, c.7987C > T, c.11248C > G, c.11251C > T, c.11257C > G, c.11257C > T, c.11346C > T, and c.11393C > G) and PKD2 (c.1480G > T) were identified to result in exon skipping. CONCLUSIONS We confirmed that 11 variants in the gene of PKD1 and PKD2 affect normal splicing by interfering the recognition of classical splicing sites or by disrupting exon splicing enhancers and generating exon splicing silencers. This is the most comprehensive study to date on pre-mRNA splicing of exonic variants in ADPKD-associated disease-causing genes in consideration of the increasing number of identified variants in PKD1 and PKD2 gene in recent years. These results emphasize the significance of assessing the effect of exon single nucleotide variants in ADPKD at the mRNA level.
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Affiliation(s)
- Xuyan Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Xiaomeng Shi
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Qing Xin
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Zhiying Liu
- Renal Division, Peking University First Hospital, Beijing, China
| | - Fengjiao Pan
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Dan Qiao
- Department of Nephrology, Dalian Medical University, Dalian, China
| | - Mengke Chen
- Department of Nephrology, Shandong First Medical University, Taian, China
| | - Yiyin Zhang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Wencong Guo
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Changying Li
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China
| | - Yan Zhang
- Department of Nephrology, Weifang Medical University, Weifang, China
| | - Leping Shao
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China.
| | - Ruixiao Zhang
- Department of Emergency, the Affiliated Qingdao Municipal Hospital of Qingdao University, No.5 Donghai Middle Road, Qingdao, 266071, China.
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Yang SP, Zhu XX, Qu ZX, Chen CY, Wu YB, Wu Y, Luo ZD, Wang XY, He CY, Fang JW, Wang LQ, Hong GL, Zheng ST, Zeng JM, Yan AF, Feng J, Liu L, Zhang XL, Zhang LG, Miao K, Tang DS. Production of MSTN knockout porcine cells using adenine base-editing-mediated exon skipping. In Vitro Cell Dev Biol Anim 2023:10.1007/s11626-023-00763-5. [PMID: 37099179 DOI: 10.1007/s11626-023-00763-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/24/2023] [Indexed: 04/27/2023]
Abstract
Gene-knockout pigs have important applications in agriculture and medicine. Compared with CRISPR/Cas9 and cytosine base editing (CBE) technologies, adenine base editing (ABE) shows better safety and accuracy in gene modification. However, because of the characteristics of gene sequences, the ABE system cannot be widely used in gene knockout. Alternative splicing of mRNA is an important biological mechanism in eukaryotes for the formation of proteins with different functional activities. The splicing apparatus recognizes conserved sequences of the 5' end splice donor and 3' end splice acceptor motifs of introns in pre-mRNA that can trigger exon skipping, leading to the production of new functional proteins, or causing gene inactivation through frameshift mutations. This study aimed to construct a MSTN knockout pig by inducing exon skipping with the aid of the ABE system to expand the application of the ABE system for the preparation of knockout pigs. In this study, first, we constructed ABEmaxAW and ABE8eV106W plasmid vectors and found that their editing efficiencies at the targets were at least sixfold and even 260-fold higher than that of ABEmaxAW by contrasting the editing efficiencies at the gene targets of endogenous CD163, IGF2, and MSTN in pigs. Subsequently, we used the ABE8eV106W system to realize adenine base (the base of the antisense strand is thymine) editing of the conserved splice donor sequence (5'-GT) of intron 2 of the porcine MSTN gene. A porcine single-cell clone carrying a homozygous mutation (5'-GC) in the conserved sequence (5'-GT) of the intron 2 splice donor of the MSTN gene was successfully generated after drug selection. Unfortunately, the MSTN gene was not expressed and, therefore, could not be characterized at this level. No detectable genomic off-target edits were identified by Sanger sequencing. In this study, we verified that the ABE8eV106W vector had higher editing efficiency and could expand the editing scope of ABE. Additionally, we successfully achieved the precise modification of the alternative splice acceptor of intron 2 of the porcine MSTN gene, which may provide a new strategy for gene knockout in pigs.
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Affiliation(s)
- Shuai-Peng Yang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Sciences and Engineering, Foshan University, Foshan, 528225, China
| | - Xiang-Xing Zhu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Sciences and Engineering, Foshan University, Foshan, 528225, China.
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China.
| | - Zi-Xiao Qu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Sciences and Engineering, Foshan University, Foshan, 528225, China
| | - Cai-Yue Chen
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Yao-Bing Wu
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Yue Wu
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Zi-Dan Luo
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Xin-Yi Wang
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Chu-Yu He
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Jia-Wen Fang
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Ling-Qi Wang
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Guang-Long Hong
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Shu-Tao Zheng
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Jie-Mei Zeng
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Ai-Fen Yan
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Juan Feng
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Lian Liu
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Xiao-Li Zhang
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Li-Gang Zhang
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China
| | - Kai Miao
- Centre for Precision Medicine Research and Training, Faculty of Health Sciences, University of Macau, Macau SAR, China.
| | - Dong-Sheng Tang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Sciences and Engineering, Foshan University, Foshan, 528225, China.
- Gene Editing Technology Center of Guangdong Province, School of Medicine, Foshan University, Foshan, 528225, China.
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11
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Anwar S, Yokota T. Morpholino-Mediated Exons 28-29 Skipping of Dysferlin and Characterization of Multiexon-skipped Dysferlin using RT-PCR, Immunoblotting, and Membrane Wounding Assay. Methods Mol Biol 2023; 2587:183-196. [PMID: 36401031 DOI: 10.1007/978-1-0716-2772-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Dysferlinopathies are a group of disabling muscular dystrophies that includes limb girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy, and distal myopathy with anterior tibial onset (DMAT) as the main phenotypes. They are associated with molecular defects in DYSF, which encodes dysferlin, a key player in sarcolemmal homeostasis. Previous investigations have suggested that exon skipping may be a promising therapy for many patients with dysferlinopathies. It was reported that exons 28-29 of DYSF are dispensable for dysferlin functions. Here, we present a method for multiexon skipping of DYSF exons 28-29 using a cocktail of two phosphorodiamidate morpholino oligomers (PMOs) on cells derived from a dystrophinopathy patient. Also, we describe assays to characterize the multiexon skipped dysferlin at several levels by using one-step RT-PCR, immunoblotting, and a membrane wounding assay.
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Affiliation(s)
- Saeed Anwar
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
- The Friends of Garrett Cumming Research and Muscular Dystrophy Canada, HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada.
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12
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He M, Yokota T. Exons 45-55 Skipping Using Antisense Oligonucleotides in Immortalized Human DMD Muscle Cells. Methods Mol Biol 2023; 2640:313-325. [PMID: 36995604 DOI: 10.1007/978-1-0716-3036-5_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Antisense oligonucleotides (AOs) have demonstrated high potential as a therapy for treating genetic diseases like Duchene muscular dystrophy (DMD). As a synthetic nucleic acid, AOs can bind to a targeted messenger RNA (mRNA) and regulate splicing. AO-mediated exon skipping transforms out-of-frame mutations as seen in DMD into in-frame transcripts. This exon skipping approach results in the production of a shortened but still functional protein product as seen in the milder counterpart, Becker muscular dystrophy (BMD). Many potential AO drugs have advanced from laboratory experimentation to clinical trials with an increasing interest in this area. An accurate and efficient method for testing AO drug candidates in vitro, before implementation in clinical trials, is crucial to ensure proper assessment of efficacy. The type of cell model used to examine AO drugs in vitro establishes the foundation of the screening process and can significantly impact the results. Previous cell models used to screen for potential AO drug candidates, such as primary muscle cell lines, have limited proliferative and differentiation capacity, and express insufficient amounts of dystrophin. Recently developed immortalized DMD muscle cell lines effectively addressed this challenge allowing for the accurate measurement of exon-skipping efficacy and dystrophin protein production. This chapter presents a procedure used to assess DMD exons 45-55 skipping efficiency and dystrophin protein production in immortalized DMD patient-derived muscle cells. Exons 45-55 skipping in the DMD gene is potentially applicable to 47% of patients. In addition, naturally occurring exons 45-55 in-frame deletion mutation is associated with an asymptomatic or remarkably mild phenotype as compared to shorter in-frame deletions within this region. As such, exons 45-55 skipping is a promising therapeutic approach to treat a wider group of DMD patients. The method presented here allows for improved examination of potential AO drugs before implementation in clinical trials for DMD.
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Affiliation(s)
- Merry He
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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13
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Echigoya Y, Yokota T. Restoring Dystrophin Expression with Exon 44 and 53 Skipping in the DMD Gene in Immortalized Myotubes. Methods Mol Biol 2023; 2587:125-139. [PMID: 36401027 DOI: 10.1007/978-1-0716-2772-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Phosphorodiamidate morpholino oligomer (PMO)-mediated exon skipping is a therapeutic approach that applies to many Duchenne muscular dystrophy (DMD) patients harboring out-of-frame deletion mutations in the DMD gene. In particular, PMOs for skipping exon 44 have been developing in clinical trials, such as the drug NS-089/NCNP-02. Two exon 53 skipping PMOs, golodirsen and viltolarsen, have received conditional approval for treating patients due to their ability to restore dystrophin protein expression. Although promising, further development of exon-skipping technology is needed for patients to have more therapeutic benefit. This chapter describes evaluation methods of exon 44 and 53 skipping PMOs in immortalized DMD patient-derived skeletal muscle cells. We introduce how to quantify exon-skipping efficiencies and dystrophin rescue levels represented by RT-PCR and western blotting, respectively. The screening methods using immortalized patient myotubes can serve to find exon-skipping PMO drug candidates.
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Affiliation(s)
- Yusuke Echigoya
- Laboratory of Biomedical Science, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan.
- Nihon University Veterinary Research Center, Fujisawa, Kanagawa, Japan.
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- The Friends of Garrett Cumming Research & Muscular Dystrophy Canada, HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada
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14
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Kunitake K, Sathyaprakash C, Motohashi N, Aoki Y. Quantitative Evaluation of Exon Skipping in Urine-Derived Cells for Duchenne Muscular Dystrophy. Methods Mol Biol 2023; 2587:153-164. [PMID: 36401029 DOI: 10.1007/978-1-0716-2772-3_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Antisense oligonucleotide (ASO)-based exon skipping therapy is thought to be promising for Duchenne muscular dystrophy (DMD). For the screening or assessing patient eligibility before administering ASO to patients, in vitro testing using myoblasts derived from each DMD patient is considered crucial. We previously reported state-of-the-art technology to obtain patient primary myoblasts from MYOD1-induced urine-derived cells (UDCs) as a model of DMD. We hypothesize that the myoblasts may potentially reflect specific pathological phenotypes, leading to a path for precision medicine in DMD patients. Here, we describe a detailed protocol for both acquiring MYOD1-induced myoblasts from UDCs and evaluating the correction of DMD mRNA and protein levels after exon-skipping in the cells.
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Affiliation(s)
- Katsuhiko Kunitake
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Chaitra Sathyaprakash
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Norio Motohashi
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan.
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15
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Goossens R, Verwey N, Ariyurek Y, Schnell F, Aartsma-Rus A. DMD antisense oligonucleotide mediated exon skipping efficiency correlates with flanking intron retention time and target position within the exon. RNA Biol 2023; 20:693-702. [PMID: 37667454 PMCID: PMC10481881 DOI: 10.1080/15476286.2023.2254041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/06/2023] Open
Abstract
Mutations in the DMD gene are causative for Duchenne muscular dystrophy (DMD). Antisense oligonucleotide (AON) mediated exon skipping to restore disrupted dystrophin reading frame is a therapeutic approach that allows production of a shorter but functional protein. As DMD causing mutations can affect most of the 79 exons encoding dystrophin, a wide variety of AONs are needed to treat the patient population. Design of AONs is largely guided by trial-and-error, and it is yet unclear what defines the skippability of an exon. Here, we use a library of phosphorodiamidate morpholino oligomer (PMOs) AONs of similar physical properties to test the skippability of a large number of DMD exons. The DMD transcript is non-sequentially spliced, meaning that certain introns are retained longer in the transcript than downstream introns. We tested whether the relative intron retention time has a significant effect on AON efficiency, and found that targeting an out-of-frame exon flanked at its 5'-end by an intron that is retained in the transcript longer ('slow' intron) leads to overall higher exon skipping efficiency than when the 5'-end flanking intron is 'fast'. Regardless of splicing speed of flanking introns, we find that positioning an AON closer to the 5'-end of the target exon leads to higher exon skipping efficiency opposed to targeting an exons 3'-end. The data enclosed herein can be of use to guide future target selection and preferential AON binding sites for both DMD and other disease amenable by exon skipping therapies.
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Affiliation(s)
- Remko Goossens
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Nisha Verwey
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Yavuz Ariyurek
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Leiden Genome Technology Center, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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16
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Sheri N, Yokota T. In Vivo Evaluation of Exon 51 Skipping in hDMD/Dmd-null Mice. Methods Mol Biol 2023; 2640:327-336. [PMID: 36995605 DOI: 10.1007/978-1-0716-3036-5_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal X-linked condition that affects 1 in 3500-6000 newborn boys a year. An out-of-frame mutation in the DMD gene typically causes the condition. Exon skipping therapy is an emerging approach that uses antisense oligonucleotides (ASOs), short synthetic DNA-like molecules that can splice out mutated or frame-disrupting mRNA fragments, to restore the reading frame. The restored reading frame will be in-frame and will produce a truncated, yet functional protein. ASOs called phosphorodiamidate morpholino oligomers (PMO), including eteplirsen, golodirsen, and viltolarsen, have recently been approved by the US Food and Drug Administration as the first ASO-based drugs for DMD. ASO-facilitated exon skipping has been extensively studied in animal models. An issue that arises with these models is that the DMD sequence differs from the human DMD sequence. A solution to this issue is to use double mutant hDMD/Dmd-null mice, which only carry the human DMD sequence and are null for the mouse Dmd sequence. Here, we describe intramuscular and intravenous injections of an ASO to skip exon 51 in hDMD/Dmd-null mice, and the evaluation of its efficacy in vivo.
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Affiliation(s)
- Narin Sheri
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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17
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Liu X, Zheng Y, Xiao M, Chen X, Zhu Y, Xu C, Wang F, Liu Z, Cao K. SRSF10 stabilizes CDC25A by triggering exon 6 skipping to promote hepatocarcinogenesis. J Exp Clin Cancer Res 2022; 41:353. [PMID: 36539837 DOI: 10.1186/s13046-022-02558-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Alternative splicing (AS) events are extensively involved in the progression of diverse tumors, but how serine/arginine-rich splicing Factor 10 (SRSF10) behaves in hepatocellular carcinoma (HCC) has not been sufficiently studied. We aimed to determine SRSF10 associated AS mechanisms and their effects on HCC progression. METHODS The expression of SRSF10 in HCC tissues was examined, and the in vitro and in vivo functions of SRSF10 were investigated. The downstream AS targets were screened using RNA sequencing. The interaction between SRSF10 protein and exclusion of cell division cycle 25 A (CDC25A) mRNA was identified using RNA immunoprecipitation and crosslinking immunoprecipitation q-PCR. The effects of SRSF10 on CDC25A posttranslational modification, subcellular distribution, and protein stability were verified through coimmunoprecipitation, immunofluorescence, and western blotting. RESULTS SRSF10 was enriched in HCC tissues and facilitated HCC proliferation, cell cycle, and invasion. RNA sequencing showed that SRSF10 promotes exon 6 exclusion of CDC25A pre-mRNA splicing. As a crucial cell cycle mediator, the exon-skipped isoform CDC25A(△E6) was identified to be stabilized and retained in the nucleus due to the deletion of two ubiquitination (Lys150, Lys169) sites in exon 6. The stabilized isoform CDC25A(△E6) derived from AS had stronger cell cycle effects on HCC tumorigenesis, and playing a more significant role than the commonly expressed longer variant CDC25A(L). Interestingly, SRSF10 activated the carcinogenesis role of CDC25A through Ser178 dephosphorylation to cause nuclear retention. Moreover, CDC25A(△E6) was verified to be indispensable for SRSF10 to promote HCC development in vitro and in vivo. CONCLUSIONS We reveal a regulatory pattern whereby SRSF10 contributes to a large proportion of stabilized CDC25A(△E6) production, which is indispensable for SRSF10 to promote HCC development. Our findings uncover AS mechanisms such as CDC25A that might serve as potential therapeutic targets to treat HCC.
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18
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Watanabe K, Gee P, Hotta A. Preparation of NanoMEDIC Extracellular Vesicles to Deliver CRISPR-Cas9 Ribonucleoproteins for Genomic Exon Skipping. Methods Mol Biol 2023; 2587:427-53. [PMID: 36401042 DOI: 10.1007/978-1-0716-2772-3_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The CRISPR-Cas9 system has quickly become the standard tool for genome editing. To deliver this system to target cells, adeno-associated virus (AAV) vectors are commonly used. In fact, AAV vectors have been utilized to deliver the CRISPR-Cas9 system to induce genomic exon skipping and restore the dystrophin protein in various Duchenne muscular dystrophy model animals. Despite the high transduction efficiency, AAV vector-mediated delivery has several limitations, such as the packaging size, prolonged overexpression of Cas9, immunogenicity against the AAV capsid, and the risk of integrating a part of the AAV genomic sequence into the host cell. To overcome these issues, we have recently engineered a transient delivery system utilizing VSV-G pseudotyped extracellular vesicles (EVs) termed NanoMEDIC (nanomembrane-derived extracellular vesicles for the delivery of macromolecular cargo). NanoMEDIC utilizes an HIV-derived Gag protein to package Cas9 protein and gRNA into EVs. The Cas9 and Gag proteins are fused to a heterodimerizer and conditionally dimerized by the addition of an inducible chemical ligand to recruit Cas9 protein into EVs. sgRNA is packaged into EVs through an HIV-derived RNA packaging signal and is subsequently released by two self-cleaving ribozymes. Utilizing these features, NanoMEDIC can achieve highly efficient packaging of the Cas9 protein and gRNA for genome editing into a variety of target cells and in vivo. Here, we describe a step-by-step protocol, including the gRNA-expressing vector construction and large-scale NanoMEDIC production, for in vivo genome editing.
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19
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Aguti S, Guirguis F, Bönnemann C, Muntoni F, Bolduc V, Zhou H. Exon-Skipping for a Pathogenic COL6A1 Variant in Ullrich Congenital Muscular Dystrophy. Methods Mol Biol 2022; 2587:387-407. [PMID: 36401040 DOI: 10.1007/978-1-0716-2772-3_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Single nucleotide variants that alter splice sites or splicing regulatory elements can lead to the skipping of exons, retention of introns, or insertion of pseudo-exons (PE) into the mature mRNA transcripts. When translated, these changes can disrupt the function of the synthesized protein. Splice-switching antisense oligonucleotides (ASOs) are synthetic, modified nucleic acids that can correct these aberrant splicing events. They are currently in active clinical development for a number of conditions and have been approved by regulatory agencies for the treatment of neuromuscular disorders such as Duchenne muscular dystrophy and spinal muscular atrophy. We have previously reported that splice-switching ASOs effectively skip a pathogenic PE that causes Ullrich congenital muscular dystrophy (UCMD). This erroneous PE insertion is caused by a deep-intronic variant located within intron 11 of COL6A1 (c.930+189 C>T). Here, we describe the detailed protocols and workflow that our labs have used to assess the efficacy of ASOs to skip this PE in vitro. The protocols include designing ASOs; isolating, culturing, and transfecting fibroblasts; extracting RNA and protein; and validating splicing correction at the mRNA and protein levels using quantitative reverse transcription PCR (qRT-PCR) and western blot assays, respectively.
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Affiliation(s)
- Sara Aguti
- The Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Fady Guirguis
- The Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Carsten Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Véronique Bolduc
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Haiyan Zhou
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK. .,Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.
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20
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Kashyap A, Tripathi G, Tripathi A, Rao R, Kashyap M, Bhat A, Kumar D, Rajhans A, Kumar P, Chandrashekar DS, Mahmood R, Husain A, Zayed H, Bharti AC, Kashyap MK. RNA splicing: a dual-edged sword for hepatocellular carcinoma. Med Oncol 2022; 39:173. [PMID: 35972700 DOI: 10.1007/s12032-022-01726-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/30/2022] [Indexed: 10/15/2022]
Abstract
RNA splicing is the fundamental process that brings diversity at the transcriptome and proteome levels. The spliceosome complex regulates minor and major processes of RNA splicing. Aberrant regulation is often associated with different diseases, including diabetes, stroke, hypertension, and cancer. In the majority of cancers, dysregulated alternative RNA splicing (ARS) events directly affect tumor progression, invasiveness, and often lead to poor survival of the patients. Alike the rest of the gastrointestinal malignancies, in hepatocellular carcinoma (HCC), which alone contributes to ~ 75% of the liver cancers, a large number of ARS events have been observed, including intron retention, exon skipping, presence of alternative 3'-splice site (3'SS), and alternative 5'-splice site (5'SS). These events are reported in spliceosome and non-spliceosome complexes genes. Molecules such as MCL1, Bcl-X, and BCL2 in different isoforms can behave as anti-apoptotic or pro-apoptotic, making the spliceosome complex a dual-edged sword. The anti-apoptotic isoforms of such molecules bring in resistance to chemotherapy or cornerstone drugs. However, in contrast, multiple malignant tumors, including HCC that target the pro-apoptotic favoring isoforms/variants favor apoptotic induction and make chemotherapy effective. Herein, we discuss different splicing events, aberrations, and antisense oligonucleotides (ASOs) in modulating RNA splicing in HCC tumorigenesis with a possible therapeutic outcome.
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21
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Li Q, Wang S, Liang P, Li W, Wang J, Fan B, Yang Y, An X, Chen J, Zha D. A novel splice site variant c.1183 + 1 G > C in DFNA5 causing autosomal dominant nonsyndromic hearing loss in a Chinese family. BMC Med Genomics 2022; 15:163. [PMID: 35864542 PMCID: PMC9306051 DOI: 10.1186/s12920-022-01315-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/11/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The most frequent clinical presentation of autosomal dominant nonsyndromic hearing loss (ADNSHL) is bilateral, symmetrical, postlingual progressive sensorineural hearing loss, which begins with impairment at high frequencies and eventually progresses to hearing loss at all frequencies. Autosomal dominant deafness-5 (DFNA5) is a subtype of ADNSHL caused by heterozygous variants in the gasdermin E (GSDME, also known as DFNA5) gene. METHODS Deafness gene NGS panel analysis were performed on the proband of a six-generation Chinese family with hearing loss. The co-segregation analysis between the hearing loss and the novel variant was analyzed by Sanger sequencing and pure-tone audiometry. The minigene splicing assay was performed to evaluate the potential effect of the variant on messenger RNA splicing in vitro. RESULTS The family exhibited autosomal dominant, progressive, postlingual, nonsyndromic sensorineural hearing loss, which was similar to that of the previously reported DFNA5 families. A novel heterozygous splice site variant in GSDME gene intron 8 was identified, which co-segregated with the hearing loss phenotype of the family. The variant caused skipping of exon 8 in the mutant transcript, leading to the direct linking of exons 7 and 9. CONCLUSIONS We identified a novel GSDME splice site variant c.1183 + 1 G > C in an extended Chinese family, which led to the skipping of exon 8. The results extended the pathogenic variants spectrum of the GSDME gene, provided further support for the 'gain-of-function' mechanism of DFNA5, and afforded a molecular interpretation for these patients with ADNSHL.
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Affiliation(s)
- Qiong Li
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Shujuan Wang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Pengfei Liang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Wei Li
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Jian Wang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Bei Fan
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Yang Yang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Xiaogang An
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China
| | - Jun Chen
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China.
| | - Dingjun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, 127 Changle West Road, Xi'an, 710032, Shaanxi, People's Republic of China.
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Takahashi T, Mercan S, Sassa T, Akçapınar GB, Yararbaş K, Süsgün S, İşeri SAU, Kihara A, Akçakaya NH. Hypomyelinating spastic dyskinesia and ichthyosis caused by a homozygous splice site mutation leading to exon skipping in ELOVL1. Brain Dev 2022; 44:391-400. [PMID: 35379526 DOI: 10.1016/j.braindev.2022.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 02/14/2022] [Accepted: 03/14/2022] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Next generation sequencing technologies allow detection of very rare pathogenic gene variants and uncover cerebral palsy. Herein, we describe two siblings with cerebral palsy due to ELOVL1 splice site mutation in autosomal recessive manner. ELOVL1 catalyzes fatty acid elongation to produce very long-chain fatty acids (VLCFAs; ≥C21), most of which are components of sphingolipids such as ceramides and sphingomyelins. Ichthyotic keratoderma, spasticity, hypomyelination, and dysmorphic facies (MIM: 618527) stem from ELOVL1 gene deficiency in human. METHODS We have studied a consanguineous family with whole exome sequencing (WES) and performed in depth analysis of cryptic splicing on the molecular level using RNA. Comprehensive analysis of ceramides in the skin stratum corneum of patients using liquid chromatography-tandem mass spectrometry (LC-MS/MS). ELOVL1 protein structure was computationally modelled. RESULTS The novel c.376-2A > G (ENST00000372458.8) homozygous variant in the affected siblings causes exon skipping. Comprehensive analysis of ceramides in the skin stratum corneum of patients using LC-MS/MS demonstrated significant shortening of fatty acid moieties and severe reduction in the levels of acylceramides. DISCUSSION It has recently been shown that disease associated variants of ELOVL1 segregate in an autosomal dominant manner. However, our study for the first time demonstrates an alternative autosomal recessive inheritance model for ELOVL1. In conclusion, we suggest that in ultra-rare diseases, being able to identify the inheritance patterns of the disease-associated gene or genes can be an important guide to identifying the molecular mechanism of genetic cerebral palsy.
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Affiliation(s)
- Taiko Takahashi
- Hokkaido University, Faculty of Pharmaceutical Sciences, Laboratory of Biochemistry, Sapporo, Japan
| | - Sevcan Mercan
- Kafkas University, Faculty of Engineering and Architecture, Department of Bioengineering, Kars, Turkey
| | - Takayuki Sassa
- Hokkaido University, Faculty of Pharmaceutical Sciences, Laboratory of Biochemistry, Sapporo, Japan
| | - Günseli Bayram Akçapınar
- Acibadem MAA University, Institute of Health Sciences, Department of Medical Biotechnology, Istanbul, Turkey
| | - Kanay Yararbaş
- Demiroglu Bilim University, Faculty of Medicine, Department of Medical Genetics, Istanbul, Turkey
| | - Seda Süsgün
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Genetics, Istanbul, Turkey; Istanbul University, Graduate School of Health Sciences, Istanbul, Turkey; Bezmialem Vakif University, Faculty of Medicine, Department of Medical Biology, Istanbul, Turkey
| | - Sibel Aylin Uğur İşeri
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Genetics, Istanbul, Turkey
| | - Akio Kihara
- Hokkaido University, Faculty of Pharmaceutical Sciences, Laboratory of Biochemistry, Sapporo, Japan
| | - Nihan Hande Akçakaya
- Demiroglu Bilim University, Faculty of Medicine, Department of Neurology, Istanbul, Turkey; Spastic Children's Foundation of Turkey, Cerebral Palsy Turkey, Istanbul, Turkey.
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Abstract
BACKGROUND In recent years the theoretical hope has become reality and the first hereditary neuromuscular diseases have become causally treatable. Neuromuscular diseases have thus become the pacemaker of this form of therapy for the whole of neurology. AIMS This article describes the principles of precision gene therapy for neurogenetic diseases using examples of neuromuscular diseases. DISCUSSION Various strategies of gene therapy have become established and are being tested in preclinical and clinical trials and evaluated as approved forms for long-term efficacy. The aim of every gene therapy is the modification or introduction of the target gene with initiation of a degradation of dysfunctional proteins. Various techniques, such as gene transfer, gene substitution or gene editing in vivo and ex vivo are now usable. For example, a modification of the pre-mRNA using antisense oligonucleotides or RNA interference (siRNA) can be used for exon skipping. An initiation of gene expression to produce the target protein can be based on a modification of the DNA by means of gene replacement, cell-based therapy (iPS cells), regulation by compensatory proteins or pharmacological treatment with so-called small molecules. Each method has advantages and complex disadvantages that must be individually evaluated. Phenotypic peculiarities of a rare disease often only become apparent through specific translational therapy. It is already becoming obvious that a very early point in timing of gene therapy is probably the most effective. Newborn screening is therefore gaining additional importance as early diagnosis can achieve the best possible success of therapies, possibly even preventively.
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Affiliation(s)
- B Schoser
- Friedrich-Baur-Institut neurologische Klinik, LMU Klinikum, Ziemssenstr. 1, 80336, München, Deutschland.
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24
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Zhu XX, Pan JS, Lin T, Yang YC, Huang QY, Yang SP, Qu ZX, Lin ZS, Wen JC, Yan AF, Feng J, Liu L, Zhang XL, Lu JH, Tang DS. Adenine base-editing-mediated exon skipping induces gene knockout in cultured pig cells. Biotechnol Lett 2022. [PMID: 34997407 DOI: 10.1007/s10529-021-03214-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/28/2021] [Indexed: 12/26/2022]
Abstract
Gene-knockout pigs have important applications in agriculture and medicine. Compared with CRISPR/Cas9, Adenine base editor (ABE) convert single A·T pairs to G·C pairs in the genome without generating DNA double-strand breaks, and this method has higher accuracy and biosafety in pig genetic modification. However, the application of ABE in pig gene knockout is limited by protospacer-adjacent motif sequences and the base-editing window. Alternative mRNA splicing is an important mechanism underlying the formation of proteins with diverse functions in eukaryotes. Spliceosome recognizes the conservative sequences of splice donors and acceptors in a precursor mRNA. Mutations in these conservative sequences induce exon skipping, leading to proteins with novel functions or to gene inactivation due to frameshift mutations. In this study, adenine base-editing-mediated exon skipping was used to expand the application of ABE in the generation of gene knockout pigs. We first constructed a modified "all-in-one" ABE vector suitable for porcine somatic cell transfection that contained an ABE for single-base editing and an sgRNA expression cassette. The "all-in-one" ABE vector induced efficient sgRNA-dependent A-to-G conversions in porcine cells during single base-editing of multiple endogenous gene loci. Subsequently, an ABE system was designed for single adenine editing of the conservative splice acceptor site (AG sequence at the 3' end of the intron 5) and splice donor site (GT sequence at the 5' end of the intron 6) in the porcine gene GHR; this method achieved highly efficient A-to-G conversion at the cellular level. Then, porcine single-cell colonies carrying a biallelic A-to-G conversion in the splice acceptor site in the intron 5 of GHR were generated. RT-PCR indicated exon 6 skipped at the mRNA level. Western blotting revealed GHR protein loss, and gene sequencing showed no sgRNA-dependent off-target effects. These results demonstrate accurate adenine base-editing-mediated exon skipping and gene knockout in porcine cells. This is the first proof-of-concept study of adenine base-editing-mediated exon skipping for gene regulation in pigs, and this work provides a new strategy for accurate and safe genetic modification of pigs for agricultural and medical applications.
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25
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Abstract
Here, we describe an in vivo model in which antisense oligonucleotides were preclinically evaluated in reconstituted patient and healthy control skin. The aim was to investigate the effect of antisense oligonucleotides upon local or systemic administration. This allows for clinically relevant evaluation of antisense oligonucleotides in an in vivo setting. In this model, primary human keratinocytes and fibroblasts were placed into silicone grafting chambers, implanted onto the back of athymic nude mice. After sufficient cells were expanded, within a few weeks, human skin grafts were generated with a high success rate. These mice bearing grafts were subsequently treated with antisense oligonucleotides targeting exon 105 of the COL7A1 gene which encodes type VII collagen. Patients completely lacking expression of type VII collagen develop severe blistering of skin and mucosa, i.e., recessive dystrophic epidermolysis bullosa. In this chapter, we describe the in vivo model used for the preclinical evaluation of antisense oligonucleotides as therapeutic approach for recessive dystrophic epidermolysis bullosa.
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Affiliation(s)
- Jeroen Bremer
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
- Department of Dermatology, Center for Blistering Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Peter C van den Akker
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Dermatology, Center for Blistering Diseases, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Division of Biological Chemistry and Drug Discovery, University of Dundee School of Life Sciences, Dundee, UK
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26
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Abstract
The genodermatosis dystrophic epidermolysis bullosa (DEB) is caused by mutations in the COL7A1 gene which encodes type VII collagen (C7). In the cutaneous basement membrane zone, C7 secures attachment of the epidermal basal keratinocyte to the papillary dermis by means of anchoring fibril formation. The complete absence of these anchoring fibrils leads to severe blistering of skin and mucosa upon the slightest friction and early mortality. To date, although preclinical advances toward therapy are promising, treatment for the disease is merely symptomatic. Therefore, research into novel therapeutics is warranted.Antisense oligonucleotide (ASO)-mediated exon skipping is such a therapy . Clinical examination of naturally occurring exon skipping suggested that this mechanism could most likely benefit the most severely affected patients. The severe form of DEB is caused by biallelic null mutations. Exon skipping aims to bind an ASO to the mutated exon of the pre-mRNA in the cell nucleus. Thereby, the ASO inhibits the recognition of the mutated exon by the splicing machinery, and as a result, the mutated exon is spliced out from the mRNA with its surrounding introns, i.e., it is skipped. Here, we describe in vitro methods to evaluate ASO-mediated exon skipping in a preclinical setting.
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Affiliation(s)
- Jeroen Bremer
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.
- University of Groningen, University Medical Center Groningen, Department of Dermatology Center for Blistering Diseases, Groningen, The Netherlands.
| | - Peter C van den Akker
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Department of Dermatology Center for Blistering Diseases, Groningen, The Netherlands
- School of Life Sciences, University of Dundee, Division of Biological Chemistry and Drug Discovery, Dundee, Scotland, UK
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27
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López-Martínez A, Soblechero-Martín P, Arechavala-Gomeza V. Evaluation of Exon Skipping and Dystrophin Restoration in In Vitro Models of Duchenne Muscular Dystrophy. Methods Mol Biol 2022; 2434:217-233. [PMID: 35213020 PMCID: PMC9703204 DOI: 10.1007/978-1-0716-2010-6_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Several exon skipping antisense oligonucleotides (eteplirsen, golodirsen, viltolarsen, and casimersen) have been approved for the treatment of Duchenne muscular dystrophy, but many more are in development targeting an array of different DMD exons. Preclinical screening of the new oligonucleotide sequences is routinely performed using patient-derived cell cultures, and evaluation of their efficacy may be performed at RNA and/or protein level. While several methods to assess exon skipping and dystrophin expression in cell culture have been developed, the choice of methodology often depends on the availability of specific research equipment.In this chapter, we describe and indicate the relevant bibliography of all the methods that may be used in this evaluation and describe in detail the protocols routinely followed at our institution, one to evaluate the efficacy of skipping at RNA level (nested PCR) and the other the restoration of protein expression (myoblot ), which provide good results using equipment largely available to most research laboratories.
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Affiliation(s)
- Andrea López-Martínez
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Patricia Soblechero-Martín
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Osakidetza Basque Health Service, Bilbao-Basurto Integrated Health Organisation, Basurto University Hospital, Clinical Laboratory Service, Bilbao, Spain
| | - Virginia Arechavala-Gomeza
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
- Neuromuscular Disorders Research Group, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.
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28
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Abstract
Duchenne muscular dystrophy (DMD) is a rare genetic disease affecting 1 in 5000 newborn boys. It is caused by mutations in the DMD gene with a consequent lack of dystrophin protein that leads to deterioration of myofibers and their replacement with fibro-adipogenic tissue. Using antisense oligonucleotides (AONs) to modify out-of-frame mutations in the DMD gene, named exon skipping, is currently considered among the most promising treatments for DMD patients. The development of this strategy is rapidly moving forward, and AONs designed to skip exons 51 and 53 have received accelerated approval in the USA. In preclinical setting, the mdx mouse model, carrying a point mutation in exon 23 of the murine Dmd gene that prevents production of dystrophin protein, has emerged as a valuable tool, and it is widely used to study in vivo therapeutic approaches for DMD. Here we describe the methodology for intravenous delivery of AONs targeting dystrophin through tail vein of mdx mice. Furthermore, the most relevant functional analyses to be performed in living mice, and the most informative histopathological and molecular assays to evaluate the effect of this treatment are detailed.
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Affiliation(s)
- Ngoc Lu-Nguyen
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, Surrey, UK
| | - Alberto Malerba
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, Surrey, UK.
| | - Linda Popplewell
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, Surrey, UK.
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29
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Yang H, Li P, Jin G, Gui D, Liu L, Zhang C. Temporal regulation of alternative splicing events in rice memory under drought stress. Plant Divers 2022; 44:116-125. [PMID: 35281128 PMCID: PMC8897166 DOI: 10.1016/j.pld.2020.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 05/03/2023]
Abstract
Plant adaptation to drought stress is essential for plant survival and crop yield. Recently, harnessing drought memory, which is induced by repeated stress and recovery cycles, was suggested as a means to improve drought resistance at the transcriptional level. However, the genetic mechanism underlying drought memory is unclear. Here, we carried out a quantitative analysis of alternative splicing (AS) events in rice memory under drought stress, generating 12 transcriptome datasets. Notably, we identified exon skipping (ES) as the predominant AS type (>80%) in differential alternative splicing (DAS) in response to drought stress. Applying our analysis pipeline to investigate DAS events following drought stress in six other plant species revealed variable ES frequencies ranging from 9.94% to 60.70% depending on the species, suggesting that the relative frequency of DAS types in plants is likely to be species-specific. The dinucleotide sequence at AS splice sites in rice following drought stress was preferentially GC-AG and AT-AC. Since U12-type splicing uses the AT-AC site, this suggests that drought stress may increase U12-type splicing, and thus increase ES frequency. We hypothesize that multiple isoforms derived from exon skipping may be induced by drought stress in rice. We also identified 20 transcription factors and three highly connected hub genes with potential roles in drought memory that may be good targets for plant breeding.
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Affiliation(s)
- Hong Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
| | - Guihua Jin
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Daping Gui
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
| | - Li Liu
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, China
- Corresponding author. Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
| | - Chengjun Zhang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China
- Haiyan Engineering & Technology Center, Kunming Institute of Botany, Chinese Academy of Science, Kunming, Yunnan, 650201, China
- Corresponding author. Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
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30
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Zhou H. Design of Bifunctional Antisense Oligonucleotides for Exon Inclusion. Methods Mol Biol 2022; 2434:53-62. [PMID: 35213009 PMCID: PMC9703293 DOI: 10.1007/978-1-0716-2010-6_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bifunctional antisense oligonucleotide (AON) is a specially designed AON to regulate pre-messenger RNA (pre-mRNA) splicing of a target gene. It is composed of two domains. The antisense domain contains sequences complementary to the target gene. The tail domain includes RNA sequences that recruit RNA binding proteins which may act positively or negatively in pre-mRNA splicing. This approach can be designed as targeted oligonucleotide enhancers of splicing, named TOES, for exon inclusion; or as targeted oligonucleotide silencers of splicing, named TOSS, for exon skipping. Here, we provide detailed methods for the design of TOES for exon inclusion, using SMN2 exon 7 splicing as an example. A number of annealing sites and the tail sequences previously published are listed. We also present methodology of assessing the effects of TOES on exon inclusion in fibroblasts cultured from a SMA patient. The effects of TOES on SMN2 exon 7 splicing were validated at RNA level by PCR and quantitative real-time PCR, and at protein level by western blotting.
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Affiliation(s)
- Haiyan Zhou
- Genetic and Genomics Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.
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31
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Abstract
Targeting of pre-mRNA splicing has yielded a rich variety of strategies for altering gene expression as a treatment for disease. The search for therapeutics that can modulate splicing has been dominated by antisense oligonucleotides (ASOs) and small molecule compounds, with each platform achieving remarkably effective results in the clinic. The success of RNA-targeting drugs has led to the exploration of new strategies to expand the repertoire of this type of therapeutic. Here, we discuss some of the more common causes of faulty gene expression and provide examples of approaches that have been developed to target and correct these defects for therapeutic value.
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Affiliation(s)
- Jessica L Centa
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
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32
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Abstract
A significant proportion of mutations underlying genetic disorders affect pre-mRNA splicing, generally causing partial or total skipping of exons, and/or inclusion of pseudoexons. These changes often lead to the formation of aberrant transcripts that can induce nonsense-mediated decay, and a subsequent lack of functional protein. For some genetic disorders, including inherited retinal diseases (IRDs), reproducing splicing dynamics in vitro is a challenge due to the specific environment provided by, e.g. the retinal tissue, cells of which cannot be easily obtained and/or cultured. Here, we describe how to engineer splicing vectors, validate the reliability and reproducibility of alternative cellular systems, assess pre-mRNA splicing defects involved in IRD, and finally correct those by using antisense oligonucleotide-based strategies.
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Affiliation(s)
- Nuria Suárez-Herrera
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tomasz Z Tomkiewicz
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alejandro Garanto
- Department of Pediatrics, Amalia Children's Hospital, Nijmegen, The Netherlands
- Department of Human Genetics and Radboud Institute of Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob W J Collin
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
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Oren YS, Avizur-Barchad O, Ozeri-Galai E, Elgrabli R, Schirelman MR, Blinder T, Stampfer CD, Ordan M, Laselva O, Cohen-Cymberknoh M, Kerem E, Bear CE, Kerem B. Antisense oligonucleotide splicing modulation as a novel Cystic Fibrosis therapeutic approach for the W1282X nonsense mutation. J Cyst Fibros 2021; 21:630-636. [PMID: 34972649 DOI: 10.1016/j.jcf.2021.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Antisense oligonucleotide- based drugs for splicing modulation were recently approved for various genetic diseases with unmet need. Here we aimed to generate skipping over exon 23 of the CFTR transcript, to eliminate the W1282X nonsense mutation and avoid RNA degradation induced by the nonsense mediated mRNA decay mechanism, allowing production of partially active CFTR proteins lacking exon 23. METHODS ∼80 ASOs were screened in 16HBEge W1282X cells. ASO candidates showing significant exon skipping were assessed for their W1282X allele selectivity and the increase of CFTR protein maturation and function. The effect of a highly potent ASO candidates was further analyzed in well differentiated primary human nasal epithelial cells, derived from a W1282X homozygous patient. RESULTS ASO screening led to identification of several ASOs that significantly decrease the level of CFTR transcripts including exon 23. These ASOs resulted in significant levels of mature CFTR protein and together with modulators restore the channel function following free uptake into these cells. Importantly, a highly potent lead ASOs, efficiently delivered by free uptake, was able to increase the level of transcripts lacking exon 23 and restore the CFTR function in cells from a W1282X homozygote patient. CONCLUSION The highly efficient exon 23 skipping induced by free uptake of the lead ASO and the resulting levels of mature CFTR protein exhibiting channel function in the presence of modulators, demonstrate the ASO therapeutic potential benefit for CF patients carrying the W1282X mutation with the objective to advance the lead candidate SPL23-2 to proof-of-concept clinical study.
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Affiliation(s)
- Yifat S Oren
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | | | - Renana Elgrabli
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | - Tehilla Blinder
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | - Merav Ordan
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | - Onofrio Laselva
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy; Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Malena Cohen-Cymberknoh
- Pediatric Pulmonology Unit and CF Center, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Eitan Kerem
- CF Center, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Christine E Bear
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Batsheva Kerem
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel; Department of Genetics, The Hebrew University, Jerusalem, Israel.
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Raktoe RS, van Haasterecht L, Antonovaite N, Bartolini L, van Doorn R, van Zuijlen PPM, Groot ML, El Ghalbzouri A. The effect of TGFβRI inhibition on extracellular matrix structure and stiffness in hypertrophic scar-specific fibroblast-derived matrix models. Biochem Biophys Res Commun 2021; 559:245-251. [PMID: 33964734 DOI: 10.1016/j.bbrc.2021.04.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/17/2021] [Indexed: 11/16/2022]
Affiliation(s)
- Rajiv S Raktoe
- Department of Dermatology, Leiden University Medical Centre, 2333 ZA, Leiden, the Netherlands.
| | - Ludo van Haasterecht
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands; Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, P.O. Box 1074, 1940 EB, Beverwijk, the Netherlands; Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB, Amsterdam, the Netherlands
| | - Nelda Antonovaite
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
| | - Luca Bartolini
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
| | - Remco van Doorn
- Department of Dermatology, Leiden University Medical Centre, 2333 ZA, Leiden, the Netherlands
| | - Paul P M van Zuijlen
- Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, P.O. Box 1074, 1940 EB, Beverwijk, the Netherlands; Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB, Amsterdam, the Netherlands
| | - Marie Louise Groot
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
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Maruyama R, Yokota T. Antisense Oligonucleotide Treatment in a Humanized Mouse Model of Duchenne Muscular Dystrophy and Highly Sensitive Detection of Dystrophin Using Western Blotting. Methods Mol Biol 2021; 2224:203-214. [PMID: 33606217 DOI: 10.1007/978-1-0716-1008-4_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating X-linked muscle disorder affecting many children. The disease is caused by the lack of dystrophin production and characterized by muscle wasting. The most common causes of death are respiratory failure and heart failure. Antisense oligonucleotide-mediated exon skipping using a phosphorodiamidate morpholino oligomer (PMO) is a promising therapeutic approach for the treatment of DMD. In preclinical studies, dystrophic mouse models are commonly used for the development of therapeutic oligos. We employ a humanized model carrying the full-length human DMD transgene along with the complete knockout of the mouse Dmd gene. In this model, the effects of human-targeting AOs can be tested without cross-reaction between mouse sequences and human sequences (note that mdx, a conventional dystrophic mouse model, carries a nonsense point mutation in exon 23 and express the full-length mouse Dmd mRNA, which is a significant complicating factor). To determine if dystrophin expression is restored, the Western blotting analysis is commonly performed; however, due to the extremely large protein size of dystrophin (427 kDa), detection and accurate quantification of full-length dystrophin can be a challenge. Here, we present methodologies to systemically inject PMOs into humanized DMD model mice and determine levels of dystrophin restoration via Western blotting. Using a tris-acetate gradient SDS gel and semi-dry transfer with three buffers, including the Concentrated Anode Buffer, Anode Buffer, and Cathode Buffer, less than 1% normal levels of dystrophin expression are easily detectable. This method is fast, easy, and sensitive enough for the detection of dystrophin from both cultured muscle cells and muscle biopsy samples.
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Affiliation(s)
- Rika Maruyama
- Faculty of Medicine and Dentistry, Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Faculty of Medicine and Dentistry, Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada. .,The Friends of Garrett Cumming Research & Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada.
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Wanitsuwan W, Vijasika S, Jirarattanasopa P, Horpaopan S. A distinct APC pathogenic germline variant identified in a southern Thai family with familial adenomatous polyposis. BMC Med Genomics 2021; 14:87. [PMID: 33740971 PMCID: PMC7980625 DOI: 10.1186/s12920-021-00933-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 11/28/2022] Open
Abstract
Background Familial adenomatous polyposis (FAP) is caused by pathogenic germline variants in the APC gene. To date, multiple pathogenic variants in coding regions, splice sites, and deep intronic regions have been revealed. However, there are still pathogenic variants that remain unidentified. Methods Twenty-nine primer pairs flanking exons 2–16 (i.e., coding exons 1–15) of APC and their exon–intron junctions were used for germline pathogenic variant screening in Southern Thai patients with familial adenomatous polyposis (FAP). Transcription analysis was performed to confirm the pathogenicity of a splice site deletion of intron 10. Family members were interviewed for clinical histories. Blood samples were collected from 18 family members for a segregation study. Subsequently, clinical data of affected members were collected from the hospital databases. Results We found a distinct heterozygous 16-bp deletion at the splice donor site of intron 10 leading to a skipping of exon 10 which was confirmed by transcript analysis (APC: c 1312 + 4_1312 + 19del, r.934_1312del). Predictive testing for the pathogenic APC variant in 18 of the proband’s family members (ten healthy and eight affected) from three generations showed the same heterozygous germline pathogenic variant in eight affected adult members (15–62 years old) and two children (7 and 10 years old). Seven of the ten carriers of the disease-causing variant had undergone colonoscopy, and colonic polyps were found in all cases, which confirmed the segregation of the inherited pathogenic variant. The phenotypic spectrum was found to vary within the family; and some affected family members exhibited extracolonic manifestations. Conclusions To our knowledge, the pathogenic APC variant, c.1312 + 4_1312 + 19del, r.934_1312del, has not previously been reported. This study is one of the few reports describing the phenotypic consequences of a pathogenic APC variant in a high number of affected family members. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-021-00933-y.
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Affiliation(s)
- Worrawit Wanitsuwan
- Department of Surgery, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Sukanya Vijasika
- Department of Surgery, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Pichai Jirarattanasopa
- Department of Ophthalmology, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Sukanya Horpaopan
- Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
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Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by loss of dystrophin protein, encoded by the DMD gene. DMD manifests early in childhood as difficulty walking, progresses to loss of ambulation by the teens, and leads to death in early adulthood. Adeno-associated virus-vectorized gene therapies to restore dystrophin protein expression using gene replacement or antisense oligonucleotide-mediated pre-mRNA splicing modulation have emerged, making great strides in uncovering barriers to gene therapies for DMD and other genetic diseases. While this first-generation of DMD therapies are being evaluated in ongoing clinical trials, uncertainties regarding durability and therapeutic efficacy prompted the development of new experimental therapies for DMD that take advantage of somatic cell gene editing. These experimental therapies continue to advance toward clinic trials, but questions remain unanswered regarding safety and translatable efficacy. Here we review the advancements toward treatment of DMD using gene editing and modulation therapies, with an emphasis on those nearest to clinical applications.
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Affiliation(s)
- Anthony A Stephenson
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States
| | - Kevin M Flanigan
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States; Department of Neurology, College of Medicine, The Ohio State University, Columbus, OH, United States.
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Takizawa H, Takeshita E, Sato M, Shimizu-Motohashi Y, Ishiyama A, Mori-Yoshimura M, Takahashi Y, Komaki H, Aoki Y. Highly sensitive screening of antisense sequences for different types of DMD mutations in patients' urine-derived cells. J Neurol Sci 2021; 423:117337. [PMID: 33610829 DOI: 10.1016/j.jns.2021.117337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 01/03/2021] [Accepted: 02/02/2021] [Indexed: 11/30/2022]
Abstract
Exon skipping using short antisense oligonucleotides (AONs) is a promising treatment for Duchenne muscular dystrophy (DMD). Several exon-skipping drugs, including viltolarsen (NS-065/NCNP-01), have been approved worldwide. Immortalized human skeletal muscle cell lines, such as rhabdomyosarcoma cells, are frequently used to screen efficient oligonucleotide sequences. However, rhabdomyosarcoma cells do not recapitulate DMD pathophysiology as they express endogenous dystrophin. To overcome this limitation, we recently established a direct human somatic cell reprogramming technology and successfully developed a cellular skeletal muscle DMD model by using myogenic differentiation 1 (MYOD1)-transduced urine-derived cells (MYOD1-UDCs). Here, we compared in vitro drug screening systems in MYOD1-UDCs and rhabdomyosarcoma cells. We collected UDCs from patients with DMD amenable to exon 51 skipping, and obtained MYOD1-UDCs. We then compared the efficiency of exon 51 skipping induced by various morpholino-based AONs, including eteplirsen in differentiated MYOD1-UDCs (UDC-myotubes) and rhabdomyosarcoma cells. Exon skipping was induced more efficiently in UDC-myotubes than in rhabdomyosarcoma cells even at a low AON concentration (1 μM). Furthermore, exon 51 skipping efficiency was higher in UDC-myotubes with a deletion of exons 49-50 than in those with a deletion of exons 48-50, suggesting that the skipping efficiency may vary depending on the DMD mutation pattern. An essential finding of this study is that the sequence of eteplirsen consistently leads to much lower efficiency than other sequences. These findings underscore the importance of AON sequence optimization by our cellular system, which enables highly sensitive screening of exon skipping drugs that target different types of DMD mutations.
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Affiliation(s)
- Hotake Takizawa
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan; Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | - Eri Takeshita
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Mitsuto Sato
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuko Shimizu-Motohashi
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Akihiko Ishiyama
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Madoka Mori-Yoshimura
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hirofumi Komaki
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
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Raktoe RS, Rietveld MH, Out-Luiting JJ, Kruithof-de Julio M, van Zuijlen PPM, van Doorn R, El Ghalbzouri A. The effect of TGFβRI inhibition on fibroblast heterogeneity in hypertrophic scar 2D in vitro models. Burns 2021; 47:1563-1575. [PMID: 33558094 DOI: 10.1016/j.burns.2021.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 12/24/2020] [Accepted: 01/11/2021] [Indexed: 12/19/2022]
Abstract
In burn patients, wound healing is often accompanied by hypertrophic scarring (HTS), resulting in both functional and aesthetic problems. HTSs are characterized by abundant presence of myofibroblasts (MFs) residing in the dermis. HTS development and MF persistence is primarily regulated by TGF-β signalling. A promising method to target the transforming growth factor receptor I (TGFβRI; also known as activin-like kinase 5 (ALK5)) is by making use of exon skipping through antisense oligonucleotides. In HTS the distinguishing border between the papillary dermis and the reticular dermis is completely abrogated, thus exhibiting a one layered dermis containing a heterogenous fibroblast population, consisting of papillary fibroblasts (PFs), reticular fibroblasts (RFs) and MFs. It has been proposed that PFs, as opposed to RFs, exhibit anti-fibrotic properties. Currently, it is still unclear which fibroblast subtype is most affected by exon skipping treatment. Therefore, the aim of this study was to investigate the effect of TGFβRI inhibition by exon skipping in PF, RF and HTS fibroblast monocultures. Morphological analyses revealed the presence of a PF-like population after exon skipping in the different fibroblast cultures. This observation was further confirmed by the expression of genes specific for PFs, demonstrated by qPCR analyses. Further investigations on mRNA and protein level revealed that indeed MFs and to a lesser extent RFs are targeted by exon skipping. Furthermore, collagen gel contraction analysis showed that ALK5 exon skipping reduced TGF-β- induced contraction together with decreased alpha-smooth muscle actin expression levels. In conclusion, we show for the first time that exon skipping primarily targets pro-fibrotic fibroblasts. This could be a promising step towards reduced HTS development of burn tissue.
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Affiliation(s)
- Rajiv S Raktoe
- Department of Dermatology, Leiden University Medical Centre (LUMC), Leiden, the Netherlands.
| | - Marion H Rietveld
- Department of Dermatology, Leiden University Medical Centre (LUMC), Leiden, the Netherlands
| | - Jacoba J Out-Luiting
- Department of Dermatology, Leiden University Medical Centre (LUMC), Leiden, the Netherlands
| | - Marianna Kruithof-de Julio
- Department of Urology, LUMC, Leiden, the Netherlands; Department of Urology, University of Bern, Bern, Switzerland
| | - Paul P M van Zuijlen
- Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam, the Netherlands; Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, Beverwijk, the Netherlands
| | - Remco van Doorn
- Department of Dermatology, Leiden University Medical Centre (LUMC), Leiden, the Netherlands
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Abstract
Duchenne muscular dystrophy (DMD) is the most common and severe form of muscular dystrophy and is caused by gene mutations that abolish production of functional dystrophin muscle protein. A promising new treatment exploits specifically targeted RNA-acting drugs that are able to partially restore the dystrophin protein. The mdx mouse model (animal model of DMD) serves as a good in vivo model for testing these antisense drugs. The simplest in vivo test, which circumvents the systemic circulation, is intramuscular administration of the compound. After 7 days it is possible to detect exon skipping by reverse transcriptase PCR, and newly synthesized dystrophin-positive fibers by immunohistochemistry and western blotting. All muscles, including the heart, are affected by the disease and must be treated. Therefore the use of antisense therapy for treatment of DMD requires systemic administration, and the model is also useful for systemic administration.
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Affiliation(s)
- Camilla Brolin
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Ernest Wee Kiat Lim
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter E Nielsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Martin N, Bergougnoux A, Baatallah N, Chevalier B, Varilh J, Baux D, Costes B, Fanen P, Raynal C, Sermet-Gaudelus I, Girodon E, Taulan-Cadars M, Hinzpeter A. Exon identity influences splicing induced by exonic variants and in silico prediction efficacy. J Cyst Fibros 2020; 20:464-472. [PMID: 33341408 DOI: 10.1016/j.jcf.2020.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 09/22/2020] [Accepted: 12/03/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND Minigenes and in silico prediction tools are commonly used to assess the impact on splicing of CFTR variants. Exon skipping is often neglected though it could impact the efficacy of targeted therapies. The aim of the study was to identify exon skipping associated with CFTR variants and to evaluate in silico predictions of seven freely available software. METHODS CFTR basal exon skipping was evaluated on endogenous mRNA extracted from non-CF nasal cells and on two CFTR minigene banks. In silico tools and minigene systems were used to evaluate the impact of CFTR exonic variants on exon skipping. RESULTS Data showed that out of 65 CFTR variants tested, 26 enhanced exon skipping and that in silico prediction efficacy was of 50%-66%. Some in silico tools presented predictions with a bias towards the occurrence of splicing events while others presented a bias towards the absence of splicing events (non-detection including true negatives and false negatives). Classification of exons depending on their basal exon skipping level increased prediction rates up to 80%. CONCLUSION This study indicates that taking basal exon skipping into account could orientate the choice of the in silico tools to improve prediction rates. It also highlights the need to validate effects using in vitro assays or mRNA studies in patients. Eventually, it shows that variant-guided therapy should also target exon skipping associated with variants.
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Affiliation(s)
- Natacha Martin
- INSERM, U955, Institut de Recherche Henri Mondor, IMRB, Créteil, France
| | - Anne Bergougnoux
- CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France; Université de Montpellier, Laboratoire de Génétique de Maladies Rares, EA7402 Montpellier, France
| | - Nesrine Baatallah
- INSERM U1151, Institut Necker Enfants Malades, INEM, Paris, France; Université Paris Descartes, Paris, France
| | - Benoit Chevalier
- INSERM U1151, Institut Necker Enfants Malades, INEM, Paris, France; Université Paris Descartes, Paris, France
| | - Jessica Varilh
- Université de Montpellier, Laboratoire de Génétique de Maladies Rares, EA7402 Montpellier, France
| | - David Baux
- CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France; Université de Montpellier, Laboratoire de Génétique de Maladies Rares, EA7402 Montpellier, France
| | - Bruno Costes
- INSERM, U955, Institut de Recherche Henri Mondor, IMRB, Créteil, France
| | - Pascale Fanen
- INSERM, U955, Institut de Recherche Henri Mondor, IMRB, Créteil, France; Department of Genetics, GH Henri Mondor, APHP, Créteil, France
| | - Caroline Raynal
- CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France; Université de Montpellier, Laboratoire de Génétique de Maladies Rares, EA7402 Montpellier, France
| | - Isabelle Sermet-Gaudelus
- INSERM U1151, Institut Necker Enfants Malades, INEM, Paris, France; Université Paris Descartes, Paris, France
| | - Emmanuelle Girodon
- INSERM U1151, Institut Necker Enfants Malades, INEM, Paris, France; Laboratoire de Génétique et Biologie Moléculaires, Hôpital Cochin, APHP Centre-Université de Paris, Paris, France
| | - Magali Taulan-Cadars
- Université de Montpellier, Laboratoire de Génétique de Maladies Rares, EA7402 Montpellier, France.
| | - Alexandre Hinzpeter
- INSERM U1151, Institut Necker Enfants Malades, INEM, Paris, France; Université Paris Descartes, Paris, France.
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Bernert G, Hahn A, Köhler C, Meyer S, Schara U, Schlachter K, Trollmann R, Walter MC. [Expert recommendation: treatment of nonambulatory patients with Duchenne muscular dystrophy]. Nervenarzt 2021; 92:359-66. [PMID: 33215271 DOI: 10.1007/s00115-020-01019-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Accepted: 09/28/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is the most frequent genetic neuromuscular disease in childhood with loss of ambulation usually occurring around the age of 9-11 years. OBJECTIVE, MATERIAL AND METHODS Based on current guidelines and clinical trials, neuropediatric and neurological experts developed recommendations for the treatment of nonambulatory DMD patients focusing on drug treatment of adults. This advisory board was sponsored by PTC Therapeutics, the distributers of the substance ataluren. RESULTS AND CONCLUSION Loss of ambulation is heterogeneously defined across clinical trials. Among others, the need of a wheelchair, ambulation without mobility aids or maximum walking distance can be suitable parameters for assessment. Treatment of DMD patients at any stage of the disease is based on supportive and symptomatic measures, which should be continued after loss of ambulation. In addition, disease-modifying drugs are available for the treatment of DMD and glucocorticoids are the usual standard of care treatment even beyond the loss of ambulation. Ataluren, a potentially dystrophin restorative, disease-modifying treatment, has been approved for patients with DMD due to a nonsense mutation (nmDMD), which applies to approximately 13% of DMD patients and is usually combined with steroids. Clinical data from the STRIDE registry demonstrated a delayed disease progression even after loss of ambulation. Currently, no reliable data are available for exon skipping approaches in adult DMD patients. The antioxidant idebenone could be an option in nonambulant adolescent patients not treated with glucocorticoids and without other therapeutic options. A combination treatment of idebenone and glucocorticoids is currently being investigated in a clinical trial. Add-on treatment with idebenone in addition to ataluren may be considered for nonambulant nmDMD patients. Some of the discussed treatment options are still in clinical trials or there are not enough data for older DMD patients; therefore, these expert recommendations correspond to evidence class IV.
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Görlacher M, Panagiotou E, Himmelreich N, Hüllen A, Beedgen L, Dimitrov B, Geiger V, Zielonka M, Peters V, Strahl S, Vázquez-Jiménez J, Kerst G, Thiel C. Fatal outcome after heart surgery in PMM2-CDG due to a rare homozygous gene variant with double effects. Mol Genet Metab Rep 2020; 25:100673. [PMID: 33209585 PMCID: PMC7658698 DOI: 10.1016/j.ymgmr.2020.100673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 10/23/2020] [Indexed: 12/19/2022] Open
Abstract
Variants in Phosphomannomutase 2 (PMM2) lead to PMM2-CDG, the most frequent congenital disorder of glycosylation (CDG). We here describe the disease course of a ten-month old patient who presented with the classical PMM2-CDG symptoms as cerebellar hypoplasia, retinitis pigmentosa, seizures, short stature, hepato- and splenomegaly, anaemia, recurrent vomiting and inverted mamillae. A severe form of tetralogy of Fallot was diagnosed and corrective surgery was performed at the age of 10 months. At the end of the cardiopulmonary bypass, a sudden oedematous reaction of the myocardium accompanied by biventricular pump failure was observed immediately after heparin antagonization with protamine sulfate. The patient died seven days after surgery, since myocardial function did not recover on ECMO support. We here describe the first patient carrying the homozygous variant g.18313A > T in the PMM2 gene (NG_009209.1) that either can lead to c.394A > T (p.I132F) or even loss of 100 bp due to exon 5 skipping (c.348_447del; p.G117Rfs*4) which is comparable to a null allele. Proliferation and doubling time of the patient's fibroblasts were affected. In addition, we show that the induction of cellular stress by elevating the cell culture temperature to 40 °C led to a decrease of the patients' PMM2 transcript as well as PMM2 protein levels and subsequently to a significant loss of residual activity. We assume that metabolic stressful processes occurring after cardiac surgery led to the drop of the patient's PMM activity below a life-sustaining niveau which paved the way for the fatal outcome.
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Affiliation(s)
- Marlen Görlacher
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | | | - Nastassja Himmelreich
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Andreas Hüllen
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Lars Beedgen
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Bianca Dimitrov
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Virginia Geiger
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Zielonka
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Verena Peters
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
| | - Sabine Strahl
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, Heidelberg, Germany
| | | | - Gunter Kerst
- Department of Pediatric Cardiology, University Hospital RWTH, Aachen, Germany
| | - Christian Thiel
- Centre for Child and Adolescent Medicine, Department I, University Hospital Heidelberg, Heidelberg, Germany
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Affiliation(s)
- Maria Gieron-Korthals
- Department of Pediatrics, Division of Child Neurology, University of South Florida, Morsani College of Medicine, 17 Davis Boulevard, Suite 200, Tampa, FL 33606, USA.
| | - Raymond Fernandez
- Pediatric Neurology Associates, 4150 North Armenia Avenue, Suite 103, Tampa, FL 33607, USA; Muscular Dystrophy Association Care Center, Shriners Hospital for Children, Tampa, FL, USA
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Hosur V, Low BE, Li D, Stafford GA, Kohar V, Shultz LD, Wiles MV. Genes adapt to outsmart gene-targeting strategies in mutant mouse strains by skipping exons to reinitiate transcription and translation. Genome Biol 2020; 21:168. [PMID: 32646486 PMCID: PMC7350591 DOI: 10.1186/s13059-020-02086-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/29/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Gene disruption in mouse embryonic stem cells or zygotes is a conventional genetics approach to identify gene function in vivo. However, because different gene disruption strategies use different mechanisms to disrupt genes, the strategies can result in diverse phenotypes in the resulting mouse model. To determine whether different gene disruption strategies affect the phenotype of resulting mutant mice, we characterized Rhbdf1 mouse mutant strains generated by three commonly used strategies-definitive-null, targeted knockout (KO)-first, and CRISPR/Cas9. RESULTS We find that Rhbdf1 responds differently to distinct KO strategies, for example, by skipping exons and reinitiating translation to potentially yield gain-of-function alleles rather than the expected null or severe hypomorphic alleles. Our analysis also revealed that at least 4% of mice generated using the KO-first strategy show conflicting phenotypes. CONCLUSIONS Exon skipping is a widespread phenomenon occurring across the genome. These findings have significant implications for the application of genome editing in both basic research and clinical practice.
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Affiliation(s)
- Vishnu Hosur
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
| | - Benjamin E. Low
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
| | - Daniel Li
- Arthritis and Tissue Degeneration Program, Hospital for Special Surgery at Weill Cornell Medicine, New York, NY 10021 USA
| | | | - Vivek Kohar
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
| | | | - Michael V. Wiles
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
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Carion N, Briand A, Cuisset L, Pacot L, Afenjar A, Bienvenu T. Loss of the KH1 domain of FMR1 in humans due to a synonymous variant causes global developmental retardation. Gene 2020; 753:144793. [PMID: 32446918 DOI: 10.1016/j.gene.2020.144793] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/30/2020] [Accepted: 05/18/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is a monogenic disorder and a common cause of intellectual disability (ID). Up to now, very few pathological variants other than the typical CGG-repeat expansion have been reported in the FMR1 gene. METHODS A panel of 56 intellectual disability (ID) genes including the FMR1 gene was sequenced in a cohort of 300 patients with unexplained ID. To determine the effect of a new FMR1 variant, total RNA from peripheral blood cells was reverse transcribed, amplified by polymerase chain reaction and sequenced. RESULTS We report a novel G to A point variant (c.801G > A) located at the last nucleotide of exon 8 in the FMR1 gene in one patient with ID. Direct sequencing of the RT-PCR products revealed that the transcript from the allele with G to A variant skips exon 8 entirely, resulting in a joining of exons 7 and 9. Skipping of exon 8 may result in an abnormal FMR1 protein (FMRP), which removes the highly conserved region that encoding the KH1 domain of FMRP. CONCLUSIONS This report describes for the first time that a synonymous variant in the FMR1 gene is associated with an error in mRNA processing, leading preferentially to the production of an aberrant transcript without exon 8. This splice variant was associated with an unspecific clinical presentation, suggesting the need for more detailed investigation of silent variants in ID patients with a large spectrum of phenotypes.
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Türkyılmaz A, Ünver O, Ekinci G, Türkdoğan D. A Novel Splice-site Mutation on the MLC1 Gene Leading to Exon 9 Skipping and Megalencephalic Leukoencephalopathy with Subcortical Cysts in a Turkish Patient. Balkan J Med Genet 2019; 22:89-92. [PMID: 31942423 DOI: 10.2478/bjmg-2019-0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Megalencephalic leukoencephalopathy (MLC) with subcortical cysts, also known as Van der Knaap disease (MIM #604004) is an autosomal recessive neurological disorder characterized by early onset macrocephaly, epilepsy, neurological deterioration with cerebellar ataxia and spasticity. An 8-month-old boy was admitted to our pediatric neurology clinic with macrocephaly. His brain magnetic resonance imaging (MRI) revealed bilateral, diffuse, symmetric structural white matter abnormalities, relatively sparing the cerebellum and bilateral subcortical temporal cysts. The diagnosis of Van der Knaap disease was suspected based on the clinical features and imaging findings and the genetic analysis revealed a novel homozygous c.768+2T>C mutation of the MLC1 gene. For determination of the novel splice-site mutation's effect, cDNA amplification was performed. cDNA analysis showed that the splice-site c.768+2T>C mutation gave rise to exon 9 skipping.
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Abstract
Drug development and pharmacotherapy of rare pediatric diseases have significantly expanded over the last decade, in part due to incentives and financial support provided by governments, regulators, and nonprofit foundations. Duchenne muscular dystrophy (DMD) is among the most common rare pediatric disorders, and clinical trials of therapeutic approaches have seen dramatic expansion. Pharmacotherapeutic standard of care has been limited to off-label prescription of high-dose, daily corticosteroids (prednisone, deflazacort). Deflazacort received FDA approval for DMD in 2016, although the price increases associated with formal FDA approval and the severe side effects associated with corticosteroid use have limited patient/physician uptake and insurance coverage in the USA. In Europe, EMA has given conditional marketing authorization for prescription of Translarna (a stop codon read-through drug prescribed to ~10% of DMD patients), although there is not yet evidence of clinical efficacy. The FDA awarded conditional approval to etiplirsen, an exon-skipping oligonucleotide drug, based on accelerated pathways (increased dystrophin production in patient muscle). Evidence of clinical efficacy remains the focus of post-marketing studies. There are many innovative pharmacotherapies under clinical development for DMD (Phase I, II, and III clinical trials). All are "disease modifying" in the sense that none seek to replace the full-length, normal DMD gene or dystrophin protein, but instead either seek to introduce an abnormal "Becker-like" version of the gene or protein or target pathophysiological pathways downstream of the primary defect. It is envisioned that the most significant benefit to DMD patients will be through multidrug approaches simultaneously aiming to introduce partially functional dystrophin in patient muscle while also targeting both chronic inflammation and the fibrofatty replacement of muscle.
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Affiliation(s)
- Eric P Hoffman
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Binghamton University State University of New York, Binghamton, NY, USA.
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Sato M, Shiba N, Miyazaki D, Shiba Y, Echigoya Y, Yokota T, Takizawa H, Aoki Y, Takeda S, Nakamura A. Amelioration of intracellular Ca 2+ regulation by exon-45 skipping in Duchenne muscular dystrophy-induced pluripotent stem cell-derived cardiomyocytes. Biochem Biophys Res Commun 2019; 520:179-185. [PMID: 31585729 DOI: 10.1016/j.bbrc.2019.09.095] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/22/2019] [Indexed: 01/02/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle disorder caused by frameshift mutations in the DMD gene. DMD involves cardiac muscle, and the presence of ventricular arrhythmias or congestive failure is critical for prognosis. Several novel therapeutic approaches are being evaluated in ongoing clinical trials. Among them, exon-skipping therapy to correct frameshift mutations with antisense oligonucleotides is promising; however, their therapeutic efficacies on cardiac muscle in vivo remain unknown. In this study, we established induced-pluripotent stem cells (iPSCs) from T cells from a DMD patient carrying a DMD-exon 46-55 deletion, differentiated the iPSCs into cardiomyocytes, and treated them with phosphorodiamidate morpholino oligomers. The efficiency of exon-45 skipping increased in a dose-dependent manner and enabled restoration of the DMD gene product, dystrophin. Further, Ca2+-imaging analysis showed a decreased number of arrhythmic cells and improved transient Ca2+ signaling after exon skipping. Thus, exon-45 skipping may be effective for cardiac involvement in DMD patients harboring the DMD-exon 46-55 deletion.
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Affiliation(s)
- Mitsuto Sato
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan
| | - Naoko Shiba
- Department of Regenerative Science and Medicine, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Daigo Miyazaki
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan; Intractable Disease Care Center, Shinshu University Hospital, Matsumoto, Nagano, 390-8621, Japan
| | - Yuji Shiba
- Department of Regenerative Science and Medicine, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Yusuke Echigoya
- Laboratory of Biomedical Science, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Hotake Takizawa
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Akinori Nakamura
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan; Department of Clinical Research, National Hospital Organization Matsumoto Medical Center, Murai-Machi Minami, Matsumoto, 399-8701, Japan.
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Abstract
For many genetic diseases, researchers are developing personalized medicine approaches. These sometimes employ custom genetic interventions such as antisense-mediated exon skipping or genome editing, aiming to restore protein function in a mutation-specific manner. Animal models can facilitate the development of personalized medicine approaches; however, given that they target human mutations and therefore human genetic sequences, scientists rely on the availability of humanized animal models. Here, we outline the usefulness, caveats and potential of such models, using the example of the hDMDdel52/mdx model, a humanized model recently generated for Duchenne muscular dystrophy (DMD).
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Affiliation(s)
- Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maaike van Putten
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
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