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Biagiotti S, Barone A, Aliano MP, Federici G, Malatesta M, Caputi C, Soddu S, Leuzzi V, Chessa L, Magnani M. Functional Classification of the ATM Variant c.7157C>A and In Vitro Effects of Dexamethasone. Front Genet 2021; 12:759467. [PMID: 34759960 PMCID: PMC8573154 DOI: 10.3389/fgene.2021.759467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/07/2021] [Indexed: 11/13/2022] Open
Abstract
Most of the ATM variants associated with Ataxia Telangiectasia are still classified as variants with uncertain significance. Ataxia Telangiectasia is a multisystemic disorder characterized by “typical” and “atypical” phenotypes, with early-onset and severe symptoms or with late-onset and mild symptoms, respectively. Here we classified the c.7157C > A ATM variant found in homozygosity in two brothers of Lebanese ethnicity. The brothers presented with an atypical phenotype, showing less than 50% of the positive criteria considered for classification. We performed several in silico analyses to predict the effect of c.7157C > A at the DNA, mRNA and protein levels, revealing that the alteration causes a missense substitution in a highly conserved alpha helix in the FAT domain. 3D structural analyses suggested that the variant might be pathogenic due to either loss of activity or to a structural damage affecting protein stability. Our subsequent in vitro studies showed that the second hypothesis is the most likely, as indicated by the reduced protein abundance found in the cells carrying the variant. Moreover, two different functional assays showed that the mutant protein partially retains its kinase activity. Finally, we investigated the in vitro effect of Dexamethasone showing that the drug is able to increase both protein abundance and activity. In conclusion, our results suggest that the c.7157C > A variant is pathogenic, although it causes an atypical phenotype, and that dexamethasone could be therapeutically effective on this and possibly other missense ATM variants.
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Affiliation(s)
- Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
| | - Ambra Barone
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
| | | | - Giulia Federici
- Department of Research and Advanced Technologies, IRCCS Regina Elena National Cancer Institute, Roma, Italy
| | - Marco Malatesta
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Caterina Caputi
- Department of Human Neuroscience, Sapienza University of Rome, Roma, Italy
| | - Silvia Soddu
- Department of Research and Advanced Technologies, IRCCS Regina Elena National Cancer Institute, Roma, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Sapienza University of Rome, Roma, Italy
| | | | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
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Ricci A, Orazi S, Biancucci F, Magnani M, Menotta M. The nucleoplasmic interactions among Lamin A/C-pRB-LAP2α-E2F1 are modulated by dexamethasone. Sci Rep 2021; 11:10099. [PMID: 33980953 PMCID: PMC8115688 DOI: 10.1038/s41598-021-89608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 04/26/2021] [Indexed: 11/09/2022] Open
Abstract
Ataxia telangiectasia (AT) is a rare genetic neurodegenerative disease. To date, there is no available cure for the illness, but the use of glucocorticoids has been shown to alleviate the neurological symptoms associated with AT. While studying the effects of dexamethasone (dex) in AT fibroblasts, by chance we observed that the nucleoplasmic Lamin A/C was affected by the drug. In addition to the structural roles of A-type lamins, Lamin A/C has been shown to play a role in the regulation of gene expression and cell cycle progression, and alterations in the LMNA gene is cause of human diseases called laminopathies. Dex was found to improve the nucleoplasmic accumulation of soluble Lamin A/C and was capable of managing the large chromatin Lamin A/C scaffolds contained complex, thus regulating epigenetics in treated cells. In addition, dex modified the interactions of Lamin A/C with its direct partners lamin associated polypeptide (LAP) 2a, Retinoblastoma 1 (pRB) and E2F Transcription Factor 1 (E2F1), regulating local gene expression dependent on E2F1. These effects were differentially observed in both AT and wild type (WT) cells. To our knowledge, this is the first reported evidence of the role of dex in Lamin A/C dynamics in AT cells, and may represent a new area of research regarding the effects of glucocorticoids on AT. Moreover, future investigations could also be extended to healthy subjects or to other pathologies such as laminopathies since glucocorticoids may have other important effects in these contexts as well.
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Affiliation(s)
- Anastasia Ricci
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Federica Biancucci
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy.
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Biagiotti S, Bianchi M, Rossi L, Chessa L, Magnani M. Activation of NRF2 by dexamethasone in ataxia telangiectasia cells involves KEAP1 inhibition but not the inhibition of p38. PLoS One 2019; 14:e0216668. [PMID: 31107893 PMCID: PMC6527213 DOI: 10.1371/journal.pone.0216668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/26/2019] [Indexed: 01/20/2023] Open
Abstract
Oxidative stress has been shown to play a crucial role in the pathophysiology of the neurodegenerative disease Ataxia Telangiectasia. We have recently demonstrated that Dexamethasone treatment is able to counteract the oxidative state by promoting nuclear factor erythroid 2-related factor 2 (NRF2) nuclear accumulation. However, substantial gaps remain in our knowledge of the underlying molecular mechanism(s) according to which Dexamethasone acts as an NRF2 inducer. Herein we investigate the possible effects of the drug on the main NRF2 activation pathways by initially focusing on key kinases known to differently affect NRF2 activation. Neither AKT nor ERK1/2, known to be NRF2-activating kinases, were found to be activated upon Dexamethasone treatment, thus excluding their involvement in the transcription factor nuclear shift. Likewise, GSK3 inactivating kinase was not inhibited, thus ruling out its role in NRF2 activation. On the other hand, p38 MAPK, another NRF2-inhibitory kinase, was indeed switched-off in Ataxia Telangiectasia cells by Dexamethasone-mediated induction of DUSP1 phosphatase, and therefore it appeared that it might account for NRF2 triggering. However, this mechanism was excluded by the use of a selective p38 inhibitor, which failed to cause a significant NRF2 nuclear shift and target gene induction. Finally, dexamethasone effects on the classical oxidative pathway orchestrated by KEAP1 were addressed. Dexamethasone was found to decrease the expression of the inhibitor KEAP1 at both mRNA and protein levels and to induce the shift from the reduced to the oxidized form of KEAP1, thus favouring NRF2 translocation into the nucleus. Furthermore, preliminary data revealed very low levels of the negative regulator Fyn in Ataxia Telangiectasia cells, which might account for the prolonged NRF2-activated gene expression.
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Affiliation(s)
- Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
- * E-mail:
| | - Marzia Bianchi
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino, Urbino, Italy
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Menotta M, Orazi S, Gioacchini AM, Spapperi C, Ricci A, Chessa L, Magnani M. Proteomics and transcriptomics analyses of ataxia telangiectasia cells treated with Dexamethasone. PLoS One 2018; 13:e0195388. [PMID: 29608596 PMCID: PMC5880408 DOI: 10.1371/journal.pone.0195388] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 03/21/2018] [Indexed: 12/21/2022] Open
Abstract
Ataxia telangiectasia (A-T) is an incurable and rare hereditary syndrome. In recent times, treatment with glucocorticoid analogues has been shown to improve the neurological symptoms that characterize this condition, but the molecular mechanism of action of these analogues remains unknown. Hence, the aim of this study was to gain insight into the molecular mechanism of action of glucocorticoid analogues in the treatment of A-T by investigating the role of Dexamethasone (Dexa) in A-T lymphoblastoid cell lines. We used 2DE and tandem MS to identify proteins that were influenced by the drug in A-T cells but not in healthy cells. Thirty-four proteins were defined out of a total of 746±63. Transcriptome analysis was performed by microarray and showed the differential expression of 599 A-T and 362 wild type (WT) genes and a healthy un-matching between protein abundance and the corresponding gene expression variation. The proteomic and transcriptomic profiles allowed the network pathway analysis to pinpoint the biological and molecular functions affected by Dexamethasone in Dexa-treated cells. The present integrated study provides evidence of the molecular mechanism of action of Dexamethasone in an A-T cellular model but also the broader effects of the drug in other tested cell lines.
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Affiliation(s)
- Michele Menotta
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | | | - Chiara Spapperi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Anastasia Ricci
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, Sapienza University, Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
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In vivo effects of dexamethasone on blood gene expression in ataxia telangiectasia. Mol Cell Biochem 2017; 438:153-166. [DOI: 10.1007/s11010-017-3122-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/15/2017] [Indexed: 12/21/2022]
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Menotta M, Biagiotti S, Spapperi C, Orazi S, Rossi L, Chessa L, Leuzzi V, D'Agnano D, Soresina A, Micheli R, Magnani M. ATM splicing variants as biomarkers for low dose dexamethasone treatment of A-T. Orphanet J Rare Dis 2017; 12:126. [PMID: 28679388 PMCID: PMC5498894 DOI: 10.1186/s13023-017-0669-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/12/2017] [Indexed: 12/31/2022] Open
Abstract
Background Ataxia Telangiectasia (AT) is a rare incurable genetic disease, caused by biallelic mutations in the Ataxia Telangiectasia-Mutated (ATM) gene. Treatment with glucocorticoid analogues has been shown to improve the neurological symptoms that characterize this syndrome. Nevertheless, the molecular mechanism underlying the glucocorticoid action in AT patients is not yet understood. Recently, we have demonstrated that Dexamethasone treatment may partly restore ATM activity in AT lymphoblastoid cells by a new ATM transcript, namely ATMdexa1. Results In the present study, the new ATMdexa1 transcript was also identified in vivo, specifically in the PMBCs of AT patients treated with intra-erythrocyte Dexamethasone (EryDex). In these patients it was also possible to isolate new “ATMdexa1 variants” originating from canonical and non-canonical splicing, each containing the coding sequence for the ATM kinase domain. The expression of the ATMdexa1 transcript family was directly related to treatment and higher expression levels of the transcript in patients’ blood correlated with a positive response to Dexamethasone therapy. Neither untreated AT patients nor untreated healthy volunteers possessed detectable levels of the transcripts. ATMdexa1 transcript expression was found to be elevated 8 days after the drug infusion, while it decreased 21 days after treatment. Conclusions For the first time, the expression of ATM splicing variants, similar to those previously observed in vitro, has been found in the PBMCs of patients treated with EryDex. These findings show a correlation between the expression of ATMdexa1 transcripts and the clinical response to low dose dexamethasone administration. Electronic supplementary material The online version of this article (doi:10.1186/s13023-017-0669-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michele Menotta
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy.
| | - Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy
| | - Chiara Spapperi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, University "La Sapienza", 00198, Rome, Italy
| | - Vincenzo Leuzzi
- Department of Pediatrics and Child Neurology and Psychiatry, University "La Sapienza", Rome, Italy
| | - Daniela D'Agnano
- Department of Pediatrics and Child Neurology and Psychiatry, University "La Sapienza", Rome, Italy
| | - Annarosa Soresina
- Department of Clinical and Experimental Sciences, Pediatrics Clinic and Institute of Molecular Medicine "A. Nocivelli", Unit of Child Neurology and Psychiatry Spedali Civili and University of Brescia, Brescia, Italy
| | - Roberto Micheli
- Department of Clinical and Experimental Sciences, Pediatrics Clinic and Institute of Molecular Medicine "A. Nocivelli", Unit of Child Neurology and Psychiatry Spedali Civili and University of Brescia, Brescia, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", 61029, Urbino, PU, Italy
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Menotta M, Biagiotti S, Bartolini G, Marzia B, Orazi S, Germani A, Chessa L, Magnani M. Nano-Mechanical Characterization of Ataxia Telangiectasia Cells Treated with Dexamethasone. Cell Biochem Biophys 2016; 75:95-102. [PMID: 27933465 DOI: 10.1007/s12013-016-0775-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
Ataxia telangiectasia is a rare genetic disease and no therapy is currently available. Glucocorticoid analogues have been shown to improve the neurological symptoms of treated patients. In the present study ataxia telangiectasia and wild type cells were used as a cellular model and treated with dexamethasone. The cells were subsequently investigated for membrane and whole cell mechanical properties by atomic force microscopy. In addition, cytoskeleton protein dynamics and nuclear shapes were assayed by fluorescence microscopy, while western blots were used to assess actin and tubulin content. At the macro level, dexamethasone directly modified the cell shape, Young's modulus and cytoskeleton protein dynamics. At the nano level, the roughness of the cell surface and the local nano-mechanical proprieties were found to be affected by Dexa. Our results show that ataxia telangiectasia and wild type cells are affected by Dexa, although there are dissimilarities in some macro-level and nano-level features between the tested cell lines. The Young's modulus of the cells appears to depend mainly on nuclear shape, with a slight contribution from the tested cytoskeleton proteins. The current study proposes that dexamethasone influences ataxia telangiectasia cell membranes contents, cell components and cell shape.
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Affiliation(s)
- Michele Menotta
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy.
| | - Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Giulia Bartolini
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Bianchi Marzia
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Aldo Germani
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
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Biagiotti S, Menotta M, Orazi S, Spapperi C, Brundu S, Fraternale A, Bianchi M, Rossi L, Chessa L, Magnani M. Dexamethasone improves redox state in ataxia telangiectasia cells by promoting an NRF2-mediated antioxidant response. FEBS J 2016; 283:3962-3978. [PMID: 27636396 DOI: 10.1111/febs.13901] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 09/12/2016] [Accepted: 09/14/2016] [Indexed: 12/17/2022]
Abstract
Ataxia telangiectasia (A-T) is a rare incurable neurodegenerative disease caused by biallelic mutations in the gene for ataxia-telangiectasia mutated (ATM). The lack of a functional ATM kinase leads to a pleiotropic phenotype, and oxidative stress is considered to have a crucial role in the complex physiopathology. Recently, steroids have been shown to reduce the neurological symptoms of the disease, although the molecular mechanism of this effect is largely unknown. In the present study, we have demonstrated that dexamethasone treatment of A-T lymphoblastoid cells increases the content of two of the most abundant antioxidants [glutathione (GSH) and NADPH] by up to 30%. Dexamethasone promoted the nuclear accumulation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 to drive expression of antioxidant pathways involved in GSH synthesis and NADPH production. The latter effect was via glucose 6-phosphate dehydrogenase activation, as confirmed by increased enzyme activity and enhancement of the pentose phosphate pathway rate. This evidence indicates that glucocorticoids are able to potentiate antioxidant defenses to counteract oxidative stress in ataxia telangiectasia, and also reveals an unexpected role for dexamethasone in redox homeostasis and cellular antioxidant activity.
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Affiliation(s)
- Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Chiara Spapperi
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Serena Brundu
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | | | - Marzia Bianchi
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, University 'La Sapienza', Roma, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Italy
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