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Wong KM, Wegener E, Baradaran-Heravi A, Huppke B, Gärtner J, Huppke P. Evaluation of Novel Enhancer Compounds in Gentamicin-Mediated Readthrough of Nonsense Mutations in Rett Syndrome. Int J Mol Sci 2023; 24:11665. [PMID: 37511424 PMCID: PMC10380790 DOI: 10.3390/ijms241411665] [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: 06/21/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Rett syndrome (RTT), a severe X-linked neurodevelopmental disorder, is primarily caused by mutations in the methyl CpG binding protein 2 gene (MECP2). Over 35% RTT patients carry nonsense mutation in MECP2, making it a suitable candidate disease for nonsense suppression therapy. In our previous study, gentamicin was found to induce readthrough of MECP2 nonsense mutations with modest efficiency. Given the recent discovery of readthrough enhancers, CDX compounds, we herein evaluated the potentiation effect of CDX5-1, CDX5-288, and CDX6-180 on gentamicin-mediated readthrough efficiency in transfected HeLa cell lines bearing the four most common MECP2 nonsense mutations. We showed that all three CDX compounds potentiated gentamicin-mediated readthrough and increased full-length MeCP2 protein levels in cells expressing the R168X, R255X, R270X, and R294X nonsense mutations. Among all three CDX compounds, CDX5-288 was the most potent enhancer and enabled the use of reduced doses of gentamicin, thus mitigating the toxicity. Furthermore, we successfully demonstrated the upregulation of full-length Mecp2 protein expression in fibroblasts derived from Mecp2R255X/Y mice through combinatorial treatment. Taken together, findings demonstrate the feasibility of this combinatorial approach to nonsense suppression therapy for a subset of RTT patients.
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Affiliation(s)
- Keit Men Wong
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
| | - Eike Wegener
- Department of Pediatrics and Adolescent Medicine, Division of Neuropediatrics, Pediatric Neurology University Medical Center Göttingen, Georg August University Göttingen, 37075 Göttingen, Germany
| | - Alireza Baradaran-Heravi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC V6T 1Z3, Canada
| | - Brenda Huppke
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, Division of Neuropediatrics, Pediatric Neurology University Medical Center Göttingen, Georg August University Göttingen, 37075 Göttingen, Germany
| | - Peter Huppke
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
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Huppke P, Wegener E, Gilley J, Angeletti C, Kurth I, Drenth JPH, Stadelmann C, Barrantes-Freer A, Brück W, Thiele H, Nürnberg P, Gärtner J, Orsomando G, Coleman MP. Homozygous NMNAT2 mutation in sisters with polyneuropathy and erythromelalgia. Exp Neurol 2019; 320:112958. [PMID: 31132363 DOI: 10.1016/j.expneurol.2019.112958] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [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: 04/25/2019] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 12/16/2022]
Abstract
We identified a homozygous missense mutation in the gene encoding NAD synthesizing enzyme NMNAT2 in two siblings with childhood onset polyneuropathy with erythromelalgia. No additional homozygotes for this rare allele, which leads to amino acid substitution T94M, were present among the unaffected relatives tested or in the 60,000 exomes of the ExAC database. For axons to survive, axonal NMNAT2 activity has to be maintained above a threshold level but the T94M mutation confers a partial loss of function both in the ability of NMNAT2 to support axon survival and in its enzymatic properties. Electrophysiological tests and histological analysis of sural nerve biopsies in the patients were consistent with loss of distal sensory and motor axons. Thus, it is likely that NMNAT2 mutation causes this pain and axon loss phenotype making this the first disorder associated with mutation of a key regulator of Wallerian-like axon degeneration in humans. This supports indications from numerous animal studies that the Wallerian degeneration pathway is important in human disease and raises important questions about which other human phenotypes could be linked to this gene.
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Affiliation(s)
- Peter Huppke
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg August University Göttingen, Germany.
| | - Eike Wegener
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg August University Göttingen, Germany.
| | - Jonathan Gilley
- John van Geest Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge CB2 0PY, UK; Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB22 3AT, UK.
| | - Carlo Angeletti
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Via Ranieri 67, 60131 Ancona, Italy.
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH, 52074 Aachen, Germany.
| | - Joost P H Drenth
- Department of Gastroenterology & Hepatology, Radboud UMC, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands.
| | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center, Georg August University Göttingen, Germany.
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center, Georg August University Göttingen, Germany; Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany.
| | - Wolfgang Brück
- Institute of Neuropathology, University Medical Center, Georg August University Göttingen, Germany.
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany.
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany.
| | - Jutta Gärtner
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg August University Göttingen, Germany.
| | - Giuseppe Orsomando
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Via Ranieri 67, 60131 Ancona, Italy.
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge CB2 0PY, UK; Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB22 3AT, UK.
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Kettwig M, Elpeleg O, Wegener E, Dreha-Kulaczewski S, Henneke M, Gärtner J, Huppke P. Compound heterozygous variants in PGAP1 causing severe psychomotor retardation, brain atrophy, recurrent apneas and delayed myelination: a case report and literature review. BMC Neurol 2016; 16:74. [PMID: 27206732 PMCID: PMC4875637 DOI: 10.1186/s12883-016-0602-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 10/17/2015] [Accepted: 05/12/2016] [Indexed: 11/25/2022] Open
Abstract
Background Mutations in proteins involved in the glycosylphosphatidylinositol anchor biosynthesis and remodeling pathway are associated with autosomal recessive forms of intellectual disability. Recently mutations in the PGAP1 gene that codes for PGAP1, a protein localized in the endoplasmic reticulum responsible for the first step of the remodeling of glycosylphosphatidylinositol was linked to a disorder characterized by psychomotor retardation and facial dysmorphism. Whole exome sequencing (WES) was performed in siblings with severely delayed myelination and psychomotor retardation. Mutations in PGAP1 were confirmed by Sanger sequencing and RNA analysis. A literature search was performed to describe the emerging phenotype of PGAP1 related disease. Case presentation WES resulted in the detection of two novel compound heterozygous mutations in PGAP1, one base pair insertion leading to a frame shift c.334_335InsA (p.A112fs) and a splice site mutation leading to exon skipping c.G1173C (p.L391L). A symptom not described in PGAP1 related disorder before but prominent in the siblings were recurrent apnea especially during sleep that persisted at least until age 2 years. Sequential cerebral MRI at age one and two year(s) respectively revealed frontal accentuated brain atrophy and significantly delayed myelination. Conclusion We report siblings with two novel mutations in PGAP1. Other that the common symptoms related to PGAP1 mutations including non-progressive psychomotor retardation, neonatal feeding problems, microcephaly and brain atrophy these patients displayed severely delayed myelination and recurrent apneas thereby widing the clinical spectrum associated with such mutations. Electronic supplementary material The online version of this article (doi:10.1186/s12883-016-0602-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthias Kettwig
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany.
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eike Wegener
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany
| | - Marco Henneke
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany
| | - Peter Huppke
- Department of Pediatrics and Pediatric Neurology, University Medical Center, Georg August University, 37075, Göttingen, Germany
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Wegener E, Brendel C, Fischer A, Hülsmann S, Gärtner J, Huppke P. Characterization of the MeCP2R168X knockin mouse model for Rett syndrome. PLoS One 2014; 9:e115444. [PMID: 25541993 PMCID: PMC4277341 DOI: 10.1371/journal.pone.0115444] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/24/2014] [Indexed: 11/19/2022] Open
Abstract
Rett syndrome, one of the most common causes of mental retardation in females, is caused by mutations in the X chromosomal gene MECP2. Mice deficient for MeCP2 recapitulate some of the symptoms seen in patients with Rett syndrome. It has been shown that reactivation of silent MECP2 alleles can reverse some of the symptoms in these mice. We have generated a knockin mouse model for translational research that carries the most common nonsense mutation in Rett syndrome, R168X. In this article we describe the phenotype of this mouse model. In male MeCP2(R168X) mice life span was reduced to 12-14 weeks and bodyweight was significantly lower than in wild type littermates. First symptoms including tremor, hind limb clasping and inactivity occurred at age 27 days. At age 6 weeks nest building, rotarod, open-field and elevated plus maze experiments showed impaired motor performance, reduced activity and decreased anxiety-like behavior. Plethysmography at the same time showed apneas and irregular breathing with reduced frequency. Female MeCP2R168X mice showed no significant abnormalities except decreased performance on the rotarod at age 9 months. In conclusion we show that the male MeCP2(R168X) mice have a phenotype similar to that seen in MECP2 knockout mouse models and are therefore well suited for translational research. The female mice, however, have a much milder and less constant phenotype making such research with this mouse model more challenging.
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Affiliation(s)
- Eike Wegener
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Cornelia Brendel
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Andre Fischer
- German Center for Neurodegenerative Diseases, Göttingen, Germany
- University Medical Center Göttingen, Department for Psychiatry and Psychotherapy, Göttingen, Germany
| | - Swen Hülsmann
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Jutta Gärtner
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Peter Huppke
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
- * E-mail:
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Kolanczyk M, Mautner V, Kossler N, Nguyen R, Kühnisch J, Zemojtel T, Jamsheer A, Wegener E, Thurisch B, Tinschert S, Holtkamp N, Park SJ, Birch P, Kendler D, Harder A, Mundlos S, Kluwe L. MIA is a potential biomarker for tumour load in neurofibromatosis type 1. BMC Med 2011; 9:82. [PMID: 21726432 PMCID: PMC3224593 DOI: 10.1186/1741-7015-9-82] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 07/04/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is a frequent genetic disease characterized by multiple benign tumours with increased risk for malignancy. There is currently no biomarker for tumour load in NF1 patients. METHODS In situ hybridization and quantitative real-time polymerase reaction were applied to investigate expression of cartilage-specific genes in mice bearing conditional inactivation of NF1 in the developing limbs. These mice do not develop tumours but recapitulate aspects of NF1 bone dysplasia, including deregulation of cartilage differentiation. It has been recently shown that NF1 tumours require for their growth the master regulator of cartilage differentiation SOX9. We thus hypothesized that some of the cartilage-specific genes deregulated in an Nf1Prx1 mouse model might prove to be relevant biomarkers of NF1 tumours. We tested this hypothesis by analyzing expression of the SOX9 target gene product melanoma-inhibitory activity/cd-rap (MIA) in tumour and serum samples of NF1 patients. RESULTS Increased expression of Mia was found in Nf1-deficient cartilage in mice. In humans, MIA was expressed in all NF1-related tumours and its serum levels were significantly higher in NF1 patients than in healthy controls. Among NF1 patients, MIA serum levels were significantly higher in those with plexiform neurofibromas and in those with large number of cutaneous (> 1,000) or subcutaneous (> 100) neurofibromas than in patients without such tumours. Most notably, MIA serum levels correlated significantly with internal tumour burden. CONCLUSIONS MIA is a potential serum biomarker of tumour load in NF1 patients which could be useful in following the disease course and monitoring the efficacy of therapies.
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Affiliation(s)
- Mateusz Kolanczyk
- Institute of Medical Genetics, Charité, Universitätsmedizin Berlin, Humboldt University, Augustenburger Platz 1, D-13353 Berlin, Germany.
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Brendel C, Belakhov V, Werner H, Wegener E, Gärtner J, Nudelman I, Baasov T, Huppke P. Readthrough of nonsense mutations in Rett syndrome: evaluation of novel aminoglycosides and generation of a new mouse model. J Mol Med (Berl) 2010; 89:389-98. [PMID: 21120444 PMCID: PMC3055984 DOI: 10.1007/s00109-010-0704-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 10/29/2010] [Accepted: 11/17/2010] [Indexed: 11/22/2022]
Abstract
Thirty-five percent of patients with Rett syndrome carry nonsense mutations in the MECP2 gene. We have recently shown in transfected HeLa cells that readthrough of nonsense mutations in the MECP2 gene can be achieved by treatment with gentamicin and geneticin. This study was performed to test if readthrough can also be achieved in cells endogenously expressing mutant MeCP2 and to evaluate potentially more effective readthrough compounds. A mouse model was generated carrying the R168X mutation in the MECP2 gene. Transfected HeLa cells expressing mutated MeCP2 fusion proteins and mouse ear fibroblasts isolated from the new mouse model were treated with gentamicin and the novel aminoglycosides NB30, NB54, and NB84. The localization of the readthrough product was tested by immunofluorescence. Readthrough of the R168X mutation in mouse ear fibroblasts using gentamicin was detected but at lower level than in HeLa cells. As expected, the readthrough product, full-length Mecp2 protein, was located in the nucleus. NB54 and NB84 induced readthrough more effectively than gentamicin, while NB30 was less effective. Readthrough of nonsense mutations can be achieved not only in transfected HeLa cells but also in fibroblasts of the newly generated Mecp2R168X mouse model. NB54 and NB84 were more effective than gentamicin and are therefore promising candidates for readthrough therapy in Rett syndrome patients.
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Affiliation(s)
- Cornelia Brendel
- Department of Pediatrics and Pediatric Neurology, Georg August University, Göttingen, Germany
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Abstract
NF-kappaB is a major regulator of the first-line defense against invading pathogens, antigen-specific adaptive immune responses or chemical stress. Stimulation either by extracellular ligands (e.g., inflammatory cytokines, microbial pathogens, peptide antigens) or by intracellular Stressors (e.g., genotoxic drugs) initiates signal-specific pathways that all converge at the IkappaB kinase (IKK) complex, the gatekeeper for NF-kappaB activation. During recent years, considerable progress has been made in understanding the function of NF-kappaB in the regulation of cell growth, survival and apoptosis. In this review, we will focus on the regulation of large signaling complexes on the route to NF-kappaB. Recently published data demonstrate that the assembly, maintenance and activity of the IKK complex determine downstream activation of NF-kappaB. In addition, dynamic complexes upstream of IKK are formed in response to tumor necrosis factor (TNF), antigenic peptides or DNA-damaging agents. Clustering of signaling adaptors promotes the association and activation of ubiquitin ligases that trigger the conjugation of regulatory ubiquitin to target proteins. Ubiquitination serves as a platform to recruit the IKK complex and potentially other protein kinases to trigger IKK activation. These findings support a concept whereby protein complex assembly induces regulatory ubiquitination, which in turn recruits and activates protein kinases. Notably, the great interest in a detailed description of the mechanisms that regulate NF-kappaB activity stems from many observations that link dysregulated NF-kappaB signaling with the onset or progression of various diseases, including cancer, chronic inflammation, cardiovascular disorders and neurodegenerative diseases. Thus, the formation of large signaling clusters and regulatory ubiquitin chains represents promising targets for pharmacological intervention to modulate NF-kappaB signal transduction in disease.
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Affiliation(s)
- E Wegener
- GSF - Research Center for Environment and Health, Institute of Toxicology, Ingolstädter Landstr. 1, Neuherberg, Germany
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Wegener E. Buchbesprechung: Konstruieren sicherheitsgerechter Produkte. Von A. Neudörfer. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.200490008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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