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Martínez-Pizarro A, Álvarez M, Dembic M, Lindegaard CA, Castro M, Richard E, Andresen BS, Desviat LR. Splice-Switching Antisense Oligonucleotides Correct Phenylalanine Hydroxylase Exon 11 Skipping Defects and Rescue Enzyme Activity in Phenylketonuria. Nucleic Acid Ther 2024. [PMID: 38591802 DOI: 10.1089/nat.2024.0014] [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: 04/10/2024] Open
Abstract
The PAH gene encodes the hepatic enzyme phenylalanine hydroxylase (PAH), and its deficiency, known as phenylketonuria (PKU), leads to neurotoxic high levels of phenylalanine. PAH exon 11 is weakly defined, and several missense and intronic variants identified in patients affect the splicing process. Recently, we identified a novel intron 11 splicing regulatory element where U1snRNP binds, participating in exon 11 definition. In this work, we describe the implementation of an antisense strategy targeting intron 11 sequences to correct the effect of PAH mis-splicing variants. We used an in vitro assay with minigenes and identified splice-switching antisense oligonucleotides (SSOs) that correct the exon skipping defect of PAH variants c.1199+17G>A, c.1199+20G>C, c.1144T>C, and c.1066-3C>T. To examine the functional rescue induced by the SSOs, we generated a hepatoma cell model with variant c.1199+17G>A using CRISPR/Cas9. The edited cell line reproduces the exon 11 skipping pattern observed from minigenes, leading to reduced PAH protein levels and activity. SSO transfection results in an increase in exon 11 inclusion and corrects PAH deficiency. Our results provide proof of concept of the potential therapeutic use of a single SSO for different exonic and intronic splicing variants causing PAH exon 11 skipping in PKU.
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Affiliation(s)
- Ainhoa Martínez-Pizarro
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, IUBM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mar Álvarez
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, IUBM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Caroline A Lindegaard
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Margarita Castro
- Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Eva Richard
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, IUBM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Lourdes R Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, IUBM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
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Spangsberg Petersen US, Dembic M, Martínez-Pizarro A, Richard E, Holm LL, Havelund JF, Doktor TK, Larsen MR, Færgeman NJ, Desviat LR, Andresen BS. Regulating PCCA gene expression by modulation of pseudoexon splicing patterns to rescue enzyme activity in propionic acidemia. Mol Ther Nucleic Acids 2024; 35:102101. [PMID: 38204914 PMCID: PMC10776996 DOI: 10.1016/j.omtn.2023.102101] [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] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
Pseudoexons are nonfunctional intronic sequences that can be activated by deep-intronic sequence variation. Activation increases pseudoexon inclusion in mRNA and interferes with normal gene expression. The PCCA c.1285-1416A>G variation activates a pseudoexon and causes the severe metabolic disorder propionic acidemia by deficiency of the propionyl-CoA carboxylase enzyme encoded by PCCA and PCCB. We characterized this pathogenic pseudoexon activation event in detail and identified hnRNP A1 to be important for normal repression. The PCCA c.1285-1416A>G variation disrupts an hnRNP A1-binding splicing silencer and simultaneously creates a splicing enhancer. We demonstrate that blocking this region of regulation with splice-switching antisense oligonucleotides restores normal splicing and rescues enzyme activity in patient fibroblasts and in a cellular model created by CRISPR gene editing. Interestingly, the PCCA pseudoexon offers an unexploited potential to upregulate gene expression because healthy tissues show relatively high inclusion levels. By blocking inclusion of the nonactivated wild-type pseudoexon, we can increase both PCCA and PCCB protein levels, which increases the activity of the heterododecameric enzyme. Surprisingly, we can increase enzyme activity from residual levels in not only patient fibroblasts harboring PCCA missense variants but also those harboring PCCB missense variants. This is a potential treatment strategy for propionic acidemia.
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Affiliation(s)
- Ulrika Simone Spangsberg Petersen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
- Department of Clinical Genetics, Odense University Hospital, 5000 Odense C, Denmark
- Department of Mathematics and Computer Science, University of Southern Denmark, 5230 Odense M, Denmark
| | - Ainhoa Martínez-Pizarro
- Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Eva Richard
- Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Lise Lolle Holm
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Jesper Foged Havelund
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Thomas Koed Doktor
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Martin Røssel Larsen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Nils J. Færgeman
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Lourdes Ruiz Desviat
- Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Brage Storstein Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
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Varzari A, Deyneko IV, Bruun GH, Dembic M, Hofmann W, Cebotari VM, Ginda SS, Andresen BS, Illig T. Candidate genes and sequence variants for susceptibility to mycobacterial infection identified by whole-exome sequencing. Front Genet 2022; 13:969895. [PMID: 36338958 PMCID: PMC9632272 DOI: 10.3389/fgene.2022.969895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 06/15/2022] [Accepted: 10/04/2022] [Indexed: 11/13/2022] Open
Abstract
Inborn errors of immunity are known to influence susceptibility to mycobacterial infections. The aim of this study was to characterize the genetic profile of nine patients with mycobacterial infections (eight with BCGitis and one with disseminated tuberculosis) from the Republic of Moldova using whole-exome sequencing. In total, 12 variants in eight genes known to be associated with Mendelian Susceptibility to Mycobacterial Disease (MSMD) were detected in six out of nine patients examined. In particular, a novel splice site mutation c.373–2A>C in STAT1 gene was found and functionally confirmed in a patient with disseminated tuberculosis. Trio analysis was possible for seven out of nine patients, and resulted in 23 candidate variants in 15 novel genes. Four of these genes - GBP2, HEATR3, PPP1R9B and KDM6A were further prioritized, considering their elevated expression in immune-related tissues. Compound heterozygosity was found in GBP2 in a single patient, comprising a maternally inherited missense variant c.412G>A/p.(Ala138Thr) predicted to be deleterious and a paternally inherited intronic mutation c.1149+14T>C. Functional studies demonstrated that the intronic mutation affects splicing and the level of transcript. Finally, we analyzed pathogenicity of variant combinations in gene pairs and identified five patients with putative oligogenic inheritance. In summary, our study expands the spectrum of genetic variation contributing to susceptibility to mycobacterial infections in children and provides insight into the complex/oligogenic disease-causing mode.
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Affiliation(s)
- Alexander Varzari
- Laboratory of Human Genetics, Chiril Draganiuc Institute of Phthisiopneumology, Kishinev, Moldova
- Hannover Unified Biobank, Hannover Medical School, Hannover, Germany
- *Correspondence: Alexander Varzari,
| | - Igor V. Deyneko
- Laboratory of Functional Genomics, Timiryazev Institute of Plant Physiology Russian Academy of Sciences, Moscow, Russia
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
- The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
- The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Winfried Hofmann
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Victor M. Cebotari
- Municipal Hospital of Phthisiopneumology, Department of Pediatrics, Kishinev, Moldova
| | - Sergei S. Ginda
- Laboratory of Immunology and Allergology, Chiril Draganiuc Institute of Phthisiopneumology, Kishinev, Moldova
| | - Brage S. Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
- The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Thomas Illig
- Hannover Unified Biobank, Hannover Medical School, Hannover, Germany
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Aaquist T, Dembic M, Thomassen M, de Stricker K, Bertelsen M, Christensen LG, Mortensen MB, Detlefsen S. Synchronous detection of pancreatic adenocarcinoma and paraganglioma in a Whipple resection specimen. Pathol Res Pract 2021; 226:153590. [PMID: 34454393 DOI: 10.1016/j.prp.2021.153590] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 08/14/2021] [Indexed: 01/17/2023]
Abstract
We report a case of a pancreatic ductal adenocarcinoma (PDAC) presenting synchronously with a paraganglioma (PGL) in a Whipple reaction specimen. The patient was a 72-year-old female with a history of breast and vulvar cancer. The simultaneous occurrence of two synchronous tumours in the pancreas was striking. Due to the presence of PGL and multiple meta- and synchronous tumours, the patient was referred to genetic counselling. Tumour tissue from the vulvar carcinoma, the PDAC and the PGL was analysed by targeted next-generation sequencing (NGS) of 161 cancer-related genes and by whole exome sequencing (WES). Peripheral blood was also examined by NGS and WES. These genetic analyses revealed germline polymorphisms in AXIN2 (NM_004655.4:c 0.2272 G>A; p.Ala758Thr), BRCA2 (NM_000059.3:c.9976 A>T; p.Lys3326Ter), NCOR1 (NM_006311.4:c 0.6544 G>A; p.Ala2182Thr) and SPTA1 (NM_003126.3:c 0.373 G>A; p.Ala125Thr) and somatic mutations of KRAS (NM_033360.3;c 0.35 G>A; p.Gly12Asp) and TP53 (NM_000546.5; c.602delT; p.Leu201CysfsTer46) in the PDAC and of TP53 (NM_000546.5; c 0.733 G>A; p.Gly245Ser) and TERT (NM_198253.2; c.-124 C>T; promotor region) in the vulvar carcinoma. Breast carcinoma tissue was not available for genetic analysis. The results of the genetic analyses did not explain the presence of multiple tumours in this patient, despite a slightly increased risk of breast cancer associated with the identified BRCA2 polymorphism. To our knowledge, this is the first report of the synchronous occurrence of PDAC and PGL. This case emphasizes the importance of thorough macroscopic examination of pancreatic resection specimens, as coexisting neoplasms may otherwise be missed.
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Affiliation(s)
- Trine Aaquist
- Department of Pathology, Odense University Hospital, Odense, Denmark; Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Maja Dembic
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark; Department of Mathematics and Computer Science (IMADA), University of Southern Denmark, Odense, Denmark
| | - Mads Thomassen
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Karin de Stricker
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Mette Bertelsen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen, Denmark
| | | | - Michael Bau Mortensen
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; Department of Surgery, Odense University Hospital, Odense, Denmark
| | - Sönke Detlefsen
- Department of Pathology, Odense University Hospital, Odense, Denmark; Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
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Guerra B, Dembic M, Siddiqui MA, Dominguez I, Ceppi P, Andresen BS. Down-Regulation of CK2α Leads toUp-Regulation of the Cyclin-Dependent Kinase Inhibitor p27 KIP1 in Conditions Unfavorable for the Growth of Myoblast Cells. Cell Physiol Biochem 2021; 54:1177-1198. [PMID: 33216476 DOI: 10.33594/000000308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2020] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND/AIMS Compelling evidence indicates that CK2α, which is one of the two catalytic isoforms of protein kinase CK2, is required for cell viability and plays an important role in cell proliferation and differentiation. While much is known on CK2 in the context of disease states, particularly cancer, its critical role in non-cancerous cell growth has not been extensively investigated. METHODS In the present study, we have employed a cell line derived from rat heart with inducible down-regulation of CK2α and CK2α-knockout mouse tissue to identify CK2-mediated molecular mechanisms regulating cell growth. For this, we have performed Incucyte® live-cell analysis and applied flow cytometry, western blot, immunoprecipitation, immunohistochemistry, RT-qPCR and luciferase-based methods. RESULTS Here, we show that lack of CK2α results in significantly delayed cell cycle progression through G1, inhibition of cyclin E-CDK2 complex, decreased phosphorylation of Rb protein at S795, and inactivation of E2F transcription factor. These events are accompanied by nuclear accumulation and up-regulation of the cyclin-dependent kinase inhibitor p27KIP1 in cells and CK2α-knockout mouse tissues. We found that increased levels of p27KIP1 are mainly attributable to post-translational modifications, namely phosphorylation at S10 and T197 amino acid residues catalyzed by Dyrk1B and AMPK, respectively, as silencing of FoxO3A transcription factor, which activates CDKN1B the gene coding for p27KIP1, does not result in markedly decreased expression levels of the corresponding protein. Interestingly, simultaneous silencing of CK2α and p27KIP1 significantly impairs cell cycle progression without increasing cell death. CONCLUSION Taken together, our study sheds light on the molecular mechanisms controlling cell cycle progression through G1 phase when myoblasts proliferation potential is impaired by CK2α depletion. Our results suggest that elevated levels of p27KIP1, which follows CK2α depletion, contribute to delay the G1-to-S phase transition. Effects seen when p27KIP1 is down-regulated are independent of CK2α and reflect the protective role exerted by p27KIP1 under unfavorable cell growth conditions.
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Affiliation(s)
- Barbara Guerra
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark,
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Mohammad A Siddiqui
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Isabel Dominguez
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Paolo Ceppi
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Dembic M, Andersen HS, Bastin J, Doktor TK, Corydon TJ, Sass JO, Lopes Costa A, Djouadi F, Andresen BS. Next generation sequencing of RNA reveals novel targets of resveratrol with possible implications for Canavan disease. Mol Genet Metab 2019; 126:64-76. [PMID: 30446350 DOI: 10.1016/j.ymgme.2018.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 08/10/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 12/21/2022]
Abstract
Resveratrol (RSV) is a small compound first identified as an activator of sirtuin 1 (SIRT1), a key factor in mediating the effects of caloric restriction. Since then, RSV received great attention for its widespread beneficial effects on health and in connection to many diseases. RSV improves the metabolism and the mitochondrial function, and more recently it was shown to restore fatty acid β-oxidation (FAO) capacities in patient fibroblasts harboring mutations with residual enzyme activity. Many of RSV's beneficial effects are mediated by the transcriptional coactivator PGC-1α, a direct target of SIRT1 and a master regulator of the mitochondrial fatty acid oxidation. Despite numerous studies RSV's mechanism of action is still not completely elucidated. Our aim was to investigate the effects of RSV on gene regulation on a wide scale, possibly to detect novel genes whose up-regulation by RSV may be of interest with respect to disease treatment. We performed Next Generation Sequencing of RNA on normal fibroblasts treated with RSV. To investigate whether the effects of RSV are mediated through SIRT1 we expanded the analysis to include SIRT1-knockdown fibroblasts. We identified the aspartoacylase (ASPA) gene, mutated in Canavan disease, to be strongly up-regulated by RSV in several cell lines, including Canavan disease fibroblasts. We further link RSV to the up-regulation of other genes involved in myelination including the glial specific transcription factors POU3F1, POU3F2, and myelin basic protein (MBP). We also observe a strong up-regulation by RSV of the riboflavin transporter gene SLC52a1. Mutations in SLC52a1 cause transient multiple acyl-CoA dehydrogenase deficiency (MADD). Our analysis of alternative splicing identified novel metabolically important genes affected by RSV, among which is particularly interesting the α subunit of the stimulatory G protein (Gsα), which regulates the cellular levels of cAMP through adenylyl cyclase. We conclude that in fibroblasts RSV stimulates the PGC-1α and p53 pathways, and up-regulates genes affecting the glucose metabolism, mitochondrial β-oxidation, and mitochondrial biogenesis. We further confirm that RSV might be a relevant treatment in the correction of FAO deficiencies and we suggest that treatment in other metabolic disorders including Canavan disease and MADD might be also beneficial.
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Affiliation(s)
- Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Henriette S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Jean Bastin
- INSERM UMR-S 1124, Université Paris Descartes, UFR Biomédicale des Saints-Pères, 45, rue des Saints-Pères, 75270 Paris, cedex 06, France
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Jörn Oliver Sass
- Research Group Inborn Errors of Metabolism, Department of Natural Sciences & IFGA, University of Applied Sciences, Rheinbach, Germany.
| | - Alexandra Lopes Costa
- INSERM UMR-S 1124, Université Paris Descartes, UFR Biomédicale des Saints-Pères, 45, rue des Saints-Pères, 75270 Paris, cedex 06, France
| | - Fatima Djouadi
- INSERM UMR-S 1124, Université Paris Descartes, UFR Biomédicale des Saints-Pères, 45, rue des Saints-Pères, 75270 Paris, cedex 06, France
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark.
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Martínez-Pizarro A, Dembic M, Pérez B, Andresen BS, Desviat LR. Intronic PAH gene mutations cause a splicing defect by a novel mechanism involving U1snRNP binding downstream of the 5' splice site. PLoS Genet 2018; 14:e1007360. [PMID: 29684050 PMCID: PMC5933811 DOI: 10.1371/journal.pgen.1007360] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/03/2018] [Accepted: 04/11/2018] [Indexed: 11/18/2022] Open
Abstract
Phenylketonuria (PKU), one of the most common inherited diseases of amino acid metabolism, is caused by mutations in the phenylalanine hydroxylase (PAH) gene. Recently, PAH exon 11 was identified as a vulnerable exon due to a weak 3’ splice site, with different exonic mutations affecting exon 11 splicing through disruption of exonic splicing regulatory elements. In this study, we report a novel intron 11 regulatory element, which is involved in exon 11 splicing, as revealed by the investigated pathogenic effect of variants c.1199+17G>A and c.1199+20G>C, identified in PKU patients. Both mutations cause exon 11 skipping in a minigene system. RNA binding assays indicate that binding of U1snRNP70 to this intronic region is disrupted, concomitant with a slightly increased binding of inhibitors hnRNPA1/2. We have investigated the effect of deletions and point mutations, as well as overexpression of adapted U1snRNA to show that this splicing regulatory motif is important for regulation of correct splicing at the natural 5’ splice site. The results indicate that U1snRNP binding downstream of the natural 5’ splice site determines efficient exon 11 splicing, thus providing a basis for development of therapeutic strategies to correct PAH exon 11 splicing mutations. In this work, we expand the functional effects of non-canonical intronic U1 snRNP binding by showing that it may enhance exon definition and that, consequently, intronic mutations may cause exon skipping by a novel mechanism, where they disrupt stimulatory U1 snRNP binding close to the 5’ splice site. Notably, our results provide further understanding of the reported therapeutic effect of exon specific U1 snRNA for splicing mutations in disease. Splicing defects constitute a major cause of human disease. Mutations affecting conserved splicing sequences at exon-intron junctions are easily recognized as possibly pathogenic, whereas variants in exonic or intronic regions are difficult to classify without functional evidence provided by transcript analysis or in vitro analysis using minigenes. In this work, we sought out to study the pathogenicity of two novel intronic PAH variants identified in phenylketonuria patients. Both mutations resulted in exon skipping in minigenes. We demonstrate that U1snRNP70 binds to the intronic region and that this binding is abolished in the mutant sequences. Correction of the splicing defect was achieved using modified U1 snRNA perfectly complementary to each of the mutant sequences. The results extend the repertoire of natural U1 snRNP cellular functions by including its role as splicing enhancer via binding downstream of the natural 5’ splice site. In addition, our results correlate with the described therapeutic effect of modified U1snRNP for splicing mutations in different genes, thus having a significant impact in the development of specific therapies for splicing defects.
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Affiliation(s)
- Ainhoa Martínez-Pizarro
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Belén Pérez
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Brage S. Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
- * E-mail: (BSA); (LRD)
| | - Lourdes R. Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
- * E-mail: (BSA); (LRD)
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Mosegaard S, Bruun GH, Flyvbjerg KF, Bliksrud YT, Gregersen N, Dembic M, Annexstad E, Tangeraas T, Olsen RKJ, Andresen BS. An intronic variation in SLC52A1 causes exon skipping and transient riboflavin-responsive multiple acyl-CoA dehydrogenation deficiency. Mol Genet Metab 2017; 122:182-188. [PMID: 29122468 DOI: 10.1016/j.ymgme.2017.10.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [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: 09/01/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/23/2022]
Abstract
Vitamin B2, riboflavin is essential for cellular function, as it participates in a diversity of redox reactions central to human metabolism, through its role as precursor for the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are electron carriers. The electron transfer flavoprotein (ETF) and its dehydrogenase (ETFDH), uses FAD as cofactor. The ETF and ETFDH are forming the electron transport pathway for many mitochondrial flavoprotein dehydrogenases involved in fatty acid, amino acid and choline metabolism. A variation in either ETF or ETFDH causes multiple acyl-CoA dehydrogenation deficiency (MADD), but genetic variations in the riboflavin metabolism or transportation of riboflavin can also cause MADD. The most common variations are located in the riboflavin transporter 2 (RFVT2) and 3 (RFVT3), that are highly expressed in brain and intestinal tissues, respectively. Deficiency of riboflavin transporter 1 (RFVT1), encoded by the SLC52A1 gene, highly expressed in the placenta, has only been reported once. We here report a case of transient MADD, caused by a heterozygous intronic variation, c.1134+11G>A, in the SLC52A1 gene encoding RFVT1. This variation creates a binding site for the splice inhibitory hnRNP A1 protein and causes exon 4 skipping. Riboflavin deficiency and maternal malnutrition during pregnancy might have been the determining factor in the outcome of this case.
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Affiliation(s)
- Signe Mosegaard
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Karen Freund Flyvbjerg
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | | | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Ellen Annexstad
- Ostfold Hospital Trust, Women's and Children's Department, Norway
| | - Trine Tangeraas
- Department of Pediatrics, Oslo University Hospital, Oslo, Norway
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark.
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Dembic M, Hedley PL, Torp-Pedersen C, Køber L, Christiansen M. Pregnancy-associated plasma protein-A (PAPP-A) and the proform of the eosinophil major basic protein (ProMBP) are associated with increased risk of death in heart failure patients. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:352-357. [DOI: 10.1080/00365513.2017.1325926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Maja Dembic
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Paula L. Hedley
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | | | - Lars Køber
- Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Michael Christiansen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
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Palhais B, Dembic M, Sabaratnam R, Nielsen KS, Doktor TK, Bruun GH, Andresen BS. The prevalent deep intronic c. 639+919 G>A GLA mutation causes pseudoexon activation and Fabry disease by abolishing the binding of hnRNPA1 and hnRNP A2/B1 to a splicing silencer. Mol Genet Metab 2016; 119:258-269. [PMID: 27595546 DOI: 10.1016/j.ymgme.2016.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 07/27/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 11/21/2022]
Abstract
Fabry disease is an X-linked recessive inborn disorder of the glycosphingolipid metabolism, caused by total or partial deficiency of the lysosomal α-galactosidase A enzyme due to mutations in the GLA gene. The prevalent c.639+919 G>A mutation in GLA leads to pathogenic insertion of a 57bp pseudoexon sequence from intron 4, which is responsible for the cardiac variant phenotype. In this study we investigate the splicing regulatory mechanism leading to GLA pseudoexon activation. Splicing analysis of GLA minigenes revealed that pseudoexon activation is influenced by cell-type. We demonstrate that the wild-type sequence harbors an hnRNP A1 and hnRNP A2/B1-binding exonic splicing silencer (ESS) overlapping the 5'splice site (5'ss) that prevents pseudoexon inclusion. The c.639+919 G>A mutation disrupts this ESS allowing U1 snRNP recognition of the 5'ss. We show that the wild-type GLA 5'ss motif with the ESS is also able to inhibit inclusion of an unrelated pseudoexon in the FGB gene, and that also in the FGB context inactivation of the ESS by the c.639+919 G>A mutation causes pseudoexon activation, underscoring the universal nature of the ESS. Finally, we demonstrate that splice switching oligonucleotide (SSO) mediated blocking of the pseudoexon 3'ss and 5'ss effectively restores normal GLA splicing. This indicates that SSO based splicing correction may be a therapeutic alternative in the treatment of Fabry disease.
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Affiliation(s)
- Bruno Palhais
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Rugivan Sabaratnam
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Kira S Nielsen
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Thomas Koed Doktor
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Brage Storstein Andresen
- Department of Biochemistry and Molecular Biology, the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark.
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11
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Doktor TK, Hua Y, Andersen HS, Brøner S, Liu YH, Wieckowska A, Dembic M, Bruun GH, Krainer AR, Andresen BS. RNA-sequencing of a mouse-model of spinal muscular atrophy reveals tissue-wide changes in splicing of U12-dependent introns. Nucleic Acids Res 2016; 45:395-416. [PMID: 27557711 PMCID: PMC5224493 DOI: 10.1093/nar/gkw731] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 11/21/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by insufficient levels of the Survival of Motor Neuron (SMN) protein. SMN is expressed ubiquitously and functions in RNA processing pathways that include trafficking of mRNA and assembly of snRNP complexes. Importantly, SMA severity is correlated with decreased snRNP assembly activity. In particular, the minor spliceosomal snRNPs are affected, and some U12-dependent introns have been reported to be aberrantly spliced in patient cells and animal models. SMA is characterized by loss of motor neurons, but the underlying mechanism is largely unknown. It is likely that aberrant splicing of genes expressed in motor neurons is involved in SMA pathogenesis, but increasing evidence indicates that pathologies also exist in other tissues. We present here a comprehensive RNA-seq study that covers multiple tissues in an SMA mouse model. We show elevated U12-intron retention in all examined tissues from SMA mice, and that U12-dependent intron retention is induced upon siRNA knock-down of SMN in HeLa cells. Furthermore, we show that retention of U12-dependent introns is mitigated by ASO treatment of SMA mice and that many transcriptional changes are reversed. Finally, we report on missplicing of several Ca2+ channel genes that may explain disrupted Ca2+ homeostasis in SMA and activation of Cdk5.
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Affiliation(s)
- Thomas Koed Doktor
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Yimin Hua
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Henriette Skovgaard Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Sabrina Brøner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Ying Hsiu Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Anna Wieckowska
- Department of Gamete and Embryo Biology, Division of Reproductive Biology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, 10-243 Olsztyn, Poland
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Brage Storstein Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark .,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
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Kanters JK, Skibsbye L, Hedley PL, Dembic M, Liang B, Hagen CM, Eschen O, Grunnet M, Christiansen M, Jespersen T. Combined gating and trafficking defect in Kv11.1 manifests as a malignant long QT syndrome phenotype in a large Danish p.F29L founder family. Scand J Clin Lab Invest 2015; 75:699-709. [PMID: 26403377 DOI: 10.3109/00365513.2015.1091090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Congenital long QT syndrome (LQTS) is a hereditary cardiac channelopathy characterized by delayed ventricular repolarization, syncope, torsades de pointes and sudden cardiac death. Thirty-three members of five apparently 'unrelated' Danish families carry the KCNH2:c.87C> A; p.F29L founder mutation. METHODS AND RESULTS Linkage disequilibrium mapping with microsatellites around KCNH2 enabled us to estimate the age of the founder mutation to be approximately 22 generations, corresponding to around 550 years. Neighbouring-Joining analysis disclosed one early and three later nodes. The median QTc time of the carriers was 490 ms (range: 415-589 ms) and no difference was seen between the different branches of the family. The mutation is malignant with a penetrance of 73%. Ten F29L carriers received implantable defibrillators (ICDs) (median age at implant 20 years), and of those four individuals experienced eight appropriate shocks. Patch-clamp analysis in HEK 293 cells, performed at 34°C disclosed a loss-of-function phenotype with fast deactivation, reduced steady-state inactivation current density and a positive voltage shift in inactivation. Western blotting of HEK 293 cells transfected with KCNH2:WT and KCNH2:c.87C> A revealed a reduced fraction of fully glycosylated hERG:p.F29L suggesting that this mutation results in defective trafficking. CONCLUSION The altered channel gating kinetics in combination with defective trafficking of mutated channels is expected to result in reduced repolarizing current density and, thus, a LQTS phenotype.
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Affiliation(s)
- Jørgen K Kanters
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,b Department of Cardiology , Herlev and Gentofte Hospitals , Denmark
| | - Lasse Skibsbye
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Paula L Hedley
- c Department for Congenital Disorders , Statens Serum Institut , Denmark.,d MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University , Aarhus , Denmark
| | - Maja Dembic
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Bo Liang
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Christian M Hagen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Ole Eschen
- e Department of Cardiology , Center for Cardiovascular Research, Aalborg Sygehus, Aarhus University Hospital , Aarhus , Denmark
| | - Morten Grunnet
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
| | - Michael Christiansen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark.,c Department for Congenital Disorders , Statens Serum Institut , Denmark
| | - Thomas Jespersen
- a Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences , University of Copenhagen , Denmark
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Hedley PL, Kanters JK, Dembic M, Jespersen T, Skibsbye L, Aidt FH, Eschen O, Graff C, Behr ER, Schlamowitz S, Corfield V, McKenna WJ, Christiansen M. The role of CAV3 in long-QT syndrome: clinical and functional assessment of a caveolin-3/Kv11.1 double heterozygote versus caveolin-3 single heterozygote. ACTA ACUST UNITED AC 2013; 6:452-61. [PMID: 24021552 DOI: 10.1161/circgenetics.113.000137] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [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: 11/16/2022]
Abstract
BACKGROUND Mutations in CAV3, coding for caveolin-3, the major constituent scaffolding protein of cardiac caveolae, have been associated with skeletal muscle disease, cardiomyopathy, and most recently long-QT syndrome (LQTS) and sudden infant death syndrome. We examined the occurrence of CAV3 mutations in a large cohort of patients with LQTS. METHODS AND RESULTS Probands with LQTS (n=167) were screened for mutations in CAV3 using direct DNA sequencing. A single proband (0.6%) was found to be a heterozygous carrier of a previously described missense mutation, caveolin-3:p.T78M. The proband was also a heterozygous carrier of the trafficking-deficient Kv11.1:p.I400N mutation. The caveolin-3:p.T78M mutation was found isolated in 3 family members, none of whom had a prolonged QTc interval. Coimmunoprecipitations of caveolin-3 and the voltage-gated potassium channel subunit (Kv11.1) were performed, and the electrophysiological classification of the Kv11.1 mutant was carried out by patch-clamp technique in human embryonic kidney 293 cells. Furthermore, the T-wave morphology was assessed in mutation carriers, double mutation carriers, and nonmutation carriers by applying a morphology combination score. The morphology combination score was normal for isolated caveolin-3:p.T78M carriers and of LQT2 type in double heterozygotes. CONCLUSIONS Mutations in CAV3 are rare in LQTS. Furthermore, caveolin-3:p.T78M did not exhibit a LQTS phenotype. Because no association has ever been found between LQTS and isolated CAV3 mutations, we suggest that LQTS9 is considered a provisional entity.
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Affiliation(s)
- Paula L Hedley
- Department of Clinical Biochemistry, Immunology, and Genetics, Statens Serum Institut, Copenhagen, Denmark
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Cipollini E, Riccio M, Di Giaimo R, Dal Piaz F, Pulice G, Catania S, Caldarelli I, Dembic M, Santi S, Melli M. Cystatin B and its EPM1 mutants are polymeric and aggregate prone in vivo. Biochim Biophys Acta 2007; 1783:312-22. [PMID: 17920138 DOI: 10.1016/j.bbamcr.2007.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 08/13/2007] [Accepted: 08/15/2007] [Indexed: 10/22/2022]
Abstract
Progressive myoclonus epilepsy type 1 (EPM1) is a neurodegenerative disease correlating with mutations of the cystatin B gene. Cystatin B is described as a monomeric protein with antiprotease function. This work shows that, in vivo, cystatin B has a polymeric structure, highly resistant to SDS, urea, boiling and sensitive to reducing agents and alkaline pH. Hydrogen peroxide increases the polymeric structure of the protein. Mass spectrometry analysis shows that the only component of the polymers is cystatin B. EPM1 mutants of cystatin B transfected in cultured cells are also polymeric. The banding pattern generated by a cysteine-minus mutant is different from that of the wild-type protein as it contains only monomers, dimers and some very high MW bands while misses components of MW intermediate between 25 and 250 kDa. Overexpression of wild-type or EPM1 mutants of cystatin B in neuroblastoma cells generates cytoplasmic aggregates. The cysteine-minus mutant is less prone to the formation of inclusion bodies. We conclude that cystatin B in vivo has a polymeric structure sensitive to the redox environment and that overexpression of the protein generates aggregates. This work describes a protein with a physiological role characterized by highly stable polymers prone to aggregate formation in vivo.
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Affiliation(s)
- Elena Cipollini
- Department of Biology, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
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15
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Carraresi L, Martinelli R, Vannoni A, Riccio M, Dembic M, Tripodi S, Cintorino M, Santi S, Bigliardi E, Carmellini M, Rossini M. Establishment and characterization of murine small cell lung carcinoma cell lines derived from HPV-16 E6/E7 transgenic mice. Cancer Lett 2006; 231:65-73. [PMID: 16356832 DOI: 10.1016/j.canlet.2005.01.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 01/12/2005] [Accepted: 01/15/2005] [Indexed: 11/19/2022]
Abstract
We have established two murine cell lines derived from Small Cell Lung Carcinomas (SCLCs) developed by HPV-E6/E7 transgenic mice. These cells named PPAP-9 and PPAP-10 were isolated from mice bearing tumors, 9 and 10 months old, respectively. The cells, 5 microm in diameter, express HPV oncoproteins and sustain tumor formation after subcutaneous injection in syngenic mice. A detailed analysis indicated the epithelial origin and the neuroendocrine differentiation of these cells. We showed by confocal immunofluorescence the expression of the epithelial marker cytokeratin 5, whose gene promoter was used to direct the expression of HPV E6/E. Cells express several neuroendocrine markers such as CGRP, MAP-2, Ash1, CgrA, Scg2. The neuroendocrine differentiation of these cells was further confirmed by electron microscopy demonstrating neuropeptides secreting granules in their cytoplasm. Furthermore, in agreement with the altered expression observed in the majority of human SCLC we showed in these cells the absence of both p53 and pRB and a dramatic reduction in the expression of Caveolin-1.
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Affiliation(s)
- Laura Carraresi
- Department of Physiopathology and Experimental Medicine, University of Siena, Via Aldo Moro, 53100 Siena, Italy
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Riccio M, Santi S, Dembic M, Di Giaimo R, Cipollini E, Costantino-Ceccarini E, Ambrosetti D, Maraldi NM, Melli M. Cell-specific expression of the epm1 (cystatin B) gene in developing rat cerebellum. Neurobiol Dis 2005; 20:104-14. [PMID: 16137571 DOI: 10.1016/j.nbd.2005.02.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 11/10/2004] [Accepted: 02/15/2005] [Indexed: 11/20/2022] Open
Abstract
Cystatin B (cystB) is an anti-protease implicated in EPM1, a degenerative disease of the central nervous system. This work analyzes the pattern of expression of cystB in developing and adult cerebellum, identifying the cystB positive cells by double immune-fluorescence microscopy using specific cell markers. In primary glial cells, cystB is found in progenitor and differentiated oligodendrocytes as well as in astrocytes. In the cerebellum, only oligodendrocyte progenitors express cystB. In myelin-producing cells, cystB synthesis is strongly down-regulated and the protein is not detectable. Astrocytes and Bergmann glia express cystB at all the developmental stages analyzed both in the cell body and in the fibers. Most neurons of developing and adult rat cerebellum do not express detectable amounts of cystB, with the exception of the Purkinje cells and of some cells of the differentiated molecular layer. In human cerebellum, cystB is present in Purkinje cells and Bergmann glial fibers only. cystB is also found in the cortical neurons of the dentate gyrus of the hippocampus. In rat cerebellum, cystB forms a complex with a number of proteins, two of which are specific to the nervous system. The cellular co-localization of cystB and its partners in developing and adult cerebellum is also shown.
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Affiliation(s)
- Massimo Riccio
- Laboratory of Cell Biology and Electron Microscopy, I.O.R., 40136 Bologna, Italy
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Affiliation(s)
- Massimo Riccio
- Laboratory of Cell Biology and Electron Microscopy, IOR, Bologna, Italy
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