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Pepe G, Fioriniello S, Marracino F, Capocci L, Maglione V, D'Esposito M, Di Pardo A, Della Ragione F. Blood–Brain Barrier Integrity Is Perturbed in a Mecp2-Null Mouse Model of Rett Syndrome. Biomolecules 2023; 13:biom13040606. [PMID: 37189354 DOI: 10.3390/biom13040606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Rett syndrome (RTT, online MIM 312750) is a devastating neurodevelopmental disorder characterized by motor and cognitive disabilities. It is mainly caused by pathogenetic variants in the X-linked MECP2 gene, encoding an epigenetic factor crucial for brain functioning. Despite intensive studies, the RTT pathogenetic mechanism remains to be fully elucidated. Impaired vascular function has been previously reported in RTT mouse models; however, whether an altered brain vascular homeostasis and the subsequent blood–brain barrier (BBB) breakdown occur in RTT and contribute to the disease-related cognitive impairment is still unknown. Interestingly, in symptomatic Mecp2-null (Mecp2-/y, Mecp2tm1.1Bird) mice, we found enhanced BBB permeability associated with an aberrant expression of the tight junction proteins Ocln and Cldn-5 in different brain areas, in terms of both transcript and protein levels. Additionally, Mecp2-null mice showed an altered expression of different genes encoding factors with a role in the BBB structure and function, such as Cldn3, Cldn12, Mpdz, Jam2, and Aqp4. With this study, we provide the first evidence of impaired BBB integrity in RTT and highlight a potential new molecular hallmark of the disease that might open new perspectives for the setting-up of novel therapeutic strategies.
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Affiliation(s)
| | - Salvatore Fioriniello
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, 80131 Naples, Italy
| | | | | | | | - Maurizio D'Esposito
- IRCCS Neuromed, 86077 Pozzilli, Italy
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, 80131 Naples, Italy
| | | | - Floriana Della Ragione
- IRCCS Neuromed, 86077 Pozzilli, Italy
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, 80131 Naples, Italy
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2
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Baroncelli L, Auel S, Rinne L, Schuster AK, Brand V, Kempkes B, Dietrich K, Müller M. Oral Feeding of an Antioxidant Cocktail as a Therapeutic Strategy in a Mouse Model of Rett Syndrome: Merits and Limitations of Long-Term Treatment. Antioxidants (Basel) 2022; 11:antiox11071406. [PMID: 35883897 PMCID: PMC9311910 DOI: 10.3390/antiox11071406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 02/01/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder that typically arises from spontaneous germline mutations in the X-chromosomal methyl-CpG binding protein 2 (MECP2) gene. For the first 6–18 months of life, the development of the mostly female patients appears normal. Subsequently, cognitive impairment, motor disturbances, hand stereotypies, epilepsy, and irregular breathing manifest, with previously learned skills being lost. Early mitochondrial impairment and a systemic oxidative burden are part of the complex pathogenesis, and contribute to disease progression. Accordingly, partial therapeutic merits of redox-stabilizing and antioxidant (AO) treatments were reported in RTT patients and Mecp2-mutant mice. Pursuing these findings, we conducted a full preclinical trial on male and female mice to define the therapeutic value of an orally administered AO cocktail composed of vitamin E, N-acetylcysteine, and α-lipoic acid. AO treatment ameliorated some of the microcephaly-related aspects. Moreover, the reduced growth, lowered blood glucose levels, and the hippocampal synaptic plasticity of Mecp2−/y mice improved. However, the first-time detected intensified oxidative DNA damage in Mecp2-mutant cortex persisted. The behavioral performance, breathing regularity, and life expectancy of Mecp2-mutant mice did not improve upon AO treatment. Long-term-treated Mecp2+/− mice eventually became obese. In conclusion, the AO cocktail ameliorated a subset of symptoms of the complex RTT-related phenotype, thereby further confirming the potential merits of AO-based pharmacotherapies. Yet, it also became evident that long-term AO treatment may lose efficacy and even aggravate the metabolic disturbances in RTT. This emphasizes the importance of a constantly well-balanced redox balance for systemic well-being.
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Affiliation(s)
- Laura Baroncelli
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
- Institute of Neuroscience, National Research Council (CNR), via Giuseppe Moruzzi 1, I-56124 Pisa, Italy
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Viale del Tirreno 331, I-56128 Pisa, Italy
| | - Stefanie Auel
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Lena Rinne
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Ann-Kathrin Schuster
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Victoria Brand
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Belinda Kempkes
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Katharina Dietrich
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
| | - Michael Müller
- Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany; (L.B.); (S.A.); (L.R.); (A.-K.S.); (V.B.); (B.K.); (K.D.)
- Correspondence: ; Tel.: +49-551-39-22933
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3
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Role of curcumin in ameliorating hypertension and associated conditions: a mechanistic insight. Mol Cell Biochem 2022; 477:2359-2385. [DOI: 10.1007/s11010-022-04447-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 04/24/2022] [Indexed: 12/23/2022]
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4
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Gomathi M, Padmapriya S, Balachandar V. Drug Studies on Rett Syndrome: From Bench to Bedside. J Autism Dev Disord 2020; 50:2740-2764. [PMID: 32016693 DOI: 10.1007/s10803-020-04381-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Drug studies on Rett syndrome (RTT) have drastically increased over the past few decades. This review aims to provide master data on bench-to-bedside drug studies involving RTT. A comprehensive literature review was performed by searching in PUBMED, MEDLINE and Google Scholar, international, national and regional clinical trial registries and pharmaceutical companies using the keywords "Rett syndrome treatment and/or drug or compound or molecule". Seventy drugs were investigated in non-clinical (N = 65 animal/cell line-based studies; N = 5 iPSC-based study) and clinical trials (N = 34) for ameliorating the symptoms of RTT. Though there is good progress in both clinical and non-clinical studies, none of these drugs entered phase III/IV for being launched as a therapeutic agent for RTT.
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Affiliation(s)
- Mohan Gomathi
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | | | - Vellingiri Balachandar
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
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Jagtap S, Thanos JM, Fu T, Wang J, Lalonde J, Dial TO, Feiglin A, Chen J, Kohane I, Lee JT, Sheridan SD, Perlis RH. Aberrant mitochondrial function in patient-derived neural cells from CDKL5 deficiency disorder and Rett syndrome. Hum Mol Genet 2020; 28:3625-3636. [PMID: 31518399 DOI: 10.1093/hmg/ddz208] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 01/09/2023] Open
Abstract
The X-linked neurodevelopmental diseases CDKL5 deficiency disorder (CDD) and Rett syndrome (RTT) are associated with intellectual disability, infantile spasms and seizures. Although mitochondrial dysfunction has been suggested in RTT, less is understood about mitochondrial function in CDD. A comparison of bioenergetics and mitochondrial function between isogenic wild-type and mutant neural progenitor cell (NPC) lines revealed increased oxygen consumption in CDD mutant lines, which is associated with altered mitochondrial function and structure. Transcriptomic analysis revealed differential expression of genes related to mitochondrial and REDOX function in NPCs expressing the mutant CDKL5. Furthermore, a similar increase in oxygen consumption specific to RTT patient-derived isogenic mutant NPCs was observed, though the pattern of mitochondrial functional alterations was distinct from CDKL5 mutant-expressing NPCs. We propose that aberrant neural bioenergetics is a common feature between CDD and RTT disorders. The observed changes in oxidative stress and mitochondrial function may facilitate the development of therapeutic agents for CDD and related disorders.
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Affiliation(s)
- Smita Jagtap
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jessica M Thanos
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Ting Fu
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jennifer Wang
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jasmin Lalonde
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Thomas O Dial
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Ariel Feiglin
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey Chen
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Isaac Kohane
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Jeannie T Lee
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Steven D Sheridan
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Roy H Perlis
- Center for Quantitative Health, Center for Genomic Medicine, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
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6
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Symons FJ, Barney CC, Byiers BJ, McAdams BD, Foster SXYL, Feyma TJ, Wendelschafer-Crabb G, Kennedy WR. A clinical case-control comparison of epidermal innervation density in Rett syndrome. Brain Behav 2019; 9:e01285. [PMID: 30980517 PMCID: PMC6520294 DOI: 10.1002/brb3.1285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 03/04/2019] [Accepted: 03/14/2019] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Rett syndrome (RTT), a rare neurodevelopmental disorder occurring primarily in females (1:10-15,000 female live births), is most often caused by loss-of-function mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2). Clinical observations and preclinical findings indicate apparent abnormal sensory and nociceptive function. There have been no direct investigations of epidermal sensory innervation in patients with RTT. METHODS We compared 3 mm epidermal punch biopsy specimens from adolescent female RTT patients (N = 4, aged 12-19 years) against an archived approximate age-, sex-, body-site matched comparison sample of healthy adolescent females (N = 8, ages 11-17). RESULTS Confocal imaging revealed, on average, statistically significant increased epidermal nerve fiber (ENF) peptidergic (co-stained calcitonin gene-related protein [CGRP]) innervation density compared with healthy female control individuals. CONCLUSIONS Given the clinical phenotype of disrupted sensory function along with diagnostic criteria specific to cold hands/feet and insensitivity to pain, our preliminary observations of ENF peptidergic fiber density differences warrants further investigation of the peripheral neurobiology in RTT.
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Affiliation(s)
- Frank J Symons
- Department of Educational Psychology, Center for Neurobehavioral Development, University of Minnesota, Minneapolis, MN
| | - Chantel C Barney
- Gillette Children's Specialty Healthcare, Research Administration, St. Paul, MN
| | - Breanne J Byiers
- Department of Educational Psychology, Center for Neurobehavioral Development, University of Minnesota, Minneapolis, MN
| | - Brian D McAdams
- Department of Neurology, Peripheral Nerve Laboratory, University of Minnesota, Minneapolis, MN
| | - Shawn X Y L Foster
- Department of Neurology, Peripheral Nerve Laboratory, University of Minnesota, Minneapolis, MN
| | - Timothy J Feyma
- Department of Pediatric Neurology, Gillette Children's Specialty Healthcare, St. Paul, MN
| | | | - William R Kennedy
- Department of Neurology, Peripheral Nerve Laboratory, University of Minnesota, Minneapolis, MN
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7
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Sanfeliu A, Hokamp K, Gill M, Tropea D. Transcriptomic Analysis of Mecp2 Mutant Mice Reveals Differentially Expressed Genes and Altered Mechanisms in Both Blood and Brain. Front Psychiatry 2019; 10:278. [PMID: 31110484 PMCID: PMC6501143 DOI: 10.3389/fpsyt.2019.00278] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 04/11/2019] [Indexed: 12/11/2022] Open
Abstract
Rett syndrome is a rare neuropsychiatric disorder with a wide symptomatology including impaired communication and movement, cardio-respiratory abnormalities, and seizures. The clinical presentation is typically associated to mutations in the gene coding for the methyl-CpG-binding protein 2 (MECP2), which is a transcription factor. The gene is ubiquitously present in all the cells of the organism with a peak of expression in neurons. For this reason, most of the studies in Rett models have been performed in brain. However, some of the symptoms of Rett are linked to the peripheral expression of MECP2, suggesting that the effects of the mutations affect gene expression levels in tissues other than the brain. We used RNA sequencing in Mecp2 mutant mice and matched controls, to identify common genes and pathways differentially regulated across different tissues. We performed our study in brain and peripheral blood, and we identified differentially expressed genes (DEGs) and pathways in each tissue. Then, we compared the genes and mechanisms identified in each preparation. We found that some genes and molecular pathways that are differentially expressed in brain are also differentially expressed in blood of Mecp2 mutant mice at a symptomatic-but not presymptomatic-stage. This is the case for the gene Ube2v1, linked to ubiquitination system, and Serpin1, involved in complement and coagulation cascades. Analysis of biological functions in the brain shows the enrichment of mechanisms correlated to circadian rhythms, while in the blood are enriched the mechanisms of response to stimulus-including immune response. Some mechanisms are enriched in both preparations, such as lipid metabolism and response to stress. These results suggest that analysis of peripheral blood can reveal ubiquitous altered molecular mechanisms of Rett and have applications in diagnosis and treatments' assessments.
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Affiliation(s)
- Albert Sanfeliu
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland
| | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Michael Gill
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland
| | - Daniela Tropea
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland
- Department of Psychiatry, School of Medicine, Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, Ireland
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Testa G, Mainardi M, Olimpico F, Pancrazi L, Cattaneo A, Caleo M, Costa M. A triheptanoin-supplemented diet rescues hippocampal hyperexcitability and seizure susceptibility in FoxG1 +/- mice. Neuropharmacology 2019; 148:305-310. [PMID: 30639390 DOI: 10.1016/j.neuropharm.2019.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/11/2018] [Accepted: 01/08/2019] [Indexed: 12/27/2022]
Abstract
The Forkhead Box G1 (FOXG1) gene encodes a transcription factor with an essential role in mammalian telencephalon development. FOXG1-related disorders, caused by deletions, intragenic mutations or duplications, are usually associated with severe intellectual disability, autistic features, and, in 87% of subjects, epileptiform manifestations. In a subset of patients with FoxG1 mutations, seizures remain intractable, prompting the need for novel therapeutic options. To address this issue, we took advantage of a haploinsufficient animal model, the FoxG1+/- mouse. In vivo electrophysiological analyses of FoxG1+/- mice detected hippocampal hyperexcitability, which turned into overt seizures upon delivery of the proconvulsant kainic acid, as confirmed by behavioral observations. These alterations were associated with decreased expression of the chloride transporter KCC2. Next, we tested whether a triheptanoin-based anaplerotic diet could have an impact on the pathological phenotype of FoxG1+/- mice. This manipulation abated altered neural activity and normalized enhanced susceptibility to proconvulsant-induced seizures, in addition to rescuing altered expression of KCC2 and increasing the levels of the GABA transporter vGAT. In conclusion, our data show that FoxG1 haploinsufficiency causes dysfunction of hippocampal circuits and increases the susceptibility to a proconvulsant insult, and that these alterations are rescued by triheptanoin dietary treatment.
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Affiliation(s)
- Giovanna Testa
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy
| | - Marco Mainardi
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy; Institute of Neuroscience, Italian National Research Council (CNR), Via Moruzzi, 1, 56124, Pisa, Italy.
| | - Francesco Olimpico
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy
| | - Laura Pancrazi
- Institute of Neuroscience, Italian National Research Council (CNR), Via Moruzzi, 1, 56124, Pisa, Italy
| | - Antonino Cattaneo
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy
| | - Matteo Caleo
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy; Institute of Neuroscience, Italian National Research Council (CNR), Via Moruzzi, 1, 56124, Pisa, Italy
| | - Mario Costa
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56124, Pisa, Italy; Institute of Neuroscience, Italian National Research Council (CNR), Via Moruzzi, 1, 56124, Pisa, Italy.
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Treating Rett syndrome: from mouse models to human therapies. Mamm Genome 2019; 30:90-110. [PMID: 30820643 PMCID: PMC6606665 DOI: 10.1007/s00335-019-09793-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 02/09/2019] [Indexed: 02/06/2023]
Abstract
Rare diseases are very difficult to study mechanistically and to develop therapies for because of the scarcity of patients. Here, the rare neuro-metabolic disorder Rett syndrome (RTT) is discussed as a prototype for precision medicine, demonstrating how mouse models have led to an understanding of the development of symptoms. RTT is caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). Mecp2-mutant mice are being used in preclinical studies that target the MECP2 gene directly, or its downstream pathways. Importantly, this work may improve the health of RTT patients. Clinical presentation may vary widely among individuals based on their mutation, but also because of the degree of X chromosome inactivation and the presence of modifier genes. Because it is a complex disorder involving many organ systems, it is likely that recovery of RTT patients will involve a combination of treatments. Precision medicine is warranted to provide the best efficacy to individually treat RTT patients.
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10
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Müller M. Disturbed redox homeostasis and oxidative stress: Potential players in the developmental regression in Rett syndrome. Neurosci Biobehav Rev 2019; 98:154-163. [PMID: 30639673 DOI: 10.1016/j.neubiorev.2018.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/30/2018] [Accepted: 12/06/2018] [Indexed: 12/16/2022]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder affecting mostly girls. A seemingly normal initial development is followed by developmental stagnation and regression, leading to severe mental impairment with autistic features, motor dysfunction, irregular breathing and epilepsy. Currently, a cure does not exist. Due to the close association of RTT with mitochondrial alterations, cellular redox-impairment and oxidative stress, compounds stabilizing mitochondrial function, cellular redox-homeostasis, and oxidant detoxification are increasingly considered as treatment concepts. Indeed, antioxidants and free-radical scavengers ameliorate certain aspects of the complex and severe clinical presentation of RTT. To further evaluate these strategies, reliable biosensors are needed to quantify redox-conditions in brain and peripheral organs of mouse models or in patient-derived cells. Genetically-encoded redox-sensors meet these requirements. Expressed in transgenic mouse-models such as our unique Rett-redox indicator mice, they will report for any cell type desired the severity of oxidant stress throughout the various disease stages of RTT. Furthermore, these sensors will be crucial to evaluate in vitro and in vivo the outcome of mitochondria- and redox-balance targeted treatments.
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Affiliation(s)
- Michael Müller
- Georg-August-Universität Göttingen, Universitätsmedizin Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Humboldtallee 23, D-37073 Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro-und Sinnesphysiologie, Humboldtallee 23, D-37073 Göttingen, Germany.
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11
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Fan C, Song Q, Wang P, Li Y, Yang M, Yu SY. Neuroprotective Effects of Curcumin on IL-1β-Induced Neuronal Apoptosis and Depression-Like Behaviors Caused by Chronic Stress in Rats. Front Cell Neurosci 2019; 12:516. [PMID: 30666189 PMCID: PMC6330766 DOI: 10.3389/fncel.2018.00516] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/12/2018] [Indexed: 12/11/2022] Open
Abstract
Depression is suggested to be a neuropsychiatric disease resulting from neuroinflammation within specific brain regions. Curcumin, a potential neuroprotective agent extracted from curcuma loga, exerts antidepressant-like effects in various animal models of depression. However, the underlying mechanisms, in particular whether curcumin may exert neuroprotection through suppression of inflammatory pathway activity in depression remains largely unknown. In the present study, we examined the molecular events of curcumin as related to its capacity for neuroprotection against inflammation-induced neuronal apoptosis and depression-like behaviors in a rat model of depression. Our results show that chronic administration of curcumin (40 mg/kg, i.p., 5 weeks) prior to stress exposure significantly alleviated depression-like behaviors, expression of the proinflammatory cytokine interleukin-1β (IL-1β) and inhibited neuronal apoptosis within neurons of the ventromedial prefrontal cortex (vmPFC). Within the vmPFC of stressed rats, an intracerebral infusion of an RNAi form of IL-1β in adenovirus associated virus (AAV-IL-1β RNAi) significantly ameliorated depression-like behaviors, neuronal apoptosis and reduced phosphorylated-p38 mitogen-activated protein kinase (p-p38 MAPK) expression levels. More important, within the vmPFC of wild type rats, overexpression of IL-1β via intracerebral infusion of AAV-IL-1β induced p38 MAPK phosphorylation and neuronal apoptosis, which could be significantly prevented by chronic treatment of curcumin. Collectively, these findings reveal that curcumin protects against IL-1β-induced neuronal apoptosis, which may be related to the display of depression-like behaviors in stressed rats. Moreover, they provide new insights into the mechanisms and therapeutic potential for curcumin in the treatment of inflammation-related neuronal deterioration in this disorder.
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Affiliation(s)
- Cuiqin Fan
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Qiqi Song
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Peng Wang
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Ye Li
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Mu Yang
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Shu Yan Yu
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China.,Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences, Shandong University, Jinan, China
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12
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Li Z, Song S, Zha S, Wang C, Chen S, Wang F. MeCP2 promotes endothelial-to-mesenchymal transition in human endothelial cells by downregulating BMP7 expression. Exp Cell Res 2018; 375:82-89. [PMID: 30597142 DOI: 10.1016/j.yexcr.2018.12.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 12/21/2018] [Accepted: 12/27/2018] [Indexed: 01/03/2023]
Abstract
Endothelial-to-mesenchymal transition (EndMT) plays a pivotal role in the development of organ fibrosis and can be induced by TGF-β. It is characterized by the loss of endothelial cell markers and the acquisition of mesenchymal markers. In this study, we found that methyl-CpG binding protein 2 (MeCP2) was increased in TGF-β-induced EndMT, and silencing of MeCP2 inhibited EndMT induction. Viral overexpression of MeCP2 in vitro promoted EndMT and suppressed the expression of bone morphogenic protein-7 (BMP7). The methylation of CpG islands in BMP7 promoter was increased in MeCP2-overexpressing endothelial cells and Chromatin immunoprecipitation assay showed the direct binding of MeCP2 at the BMP7 promoter. In summary, our results suggest that MeCP2 promotes EndMT by epigenetically silencing BMP7 in endothelial cells and MeCP2 may be a target for diseases driven by EndMT.
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Affiliation(s)
- Zhen Li
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, China.
| | - Shuai Song
- Department of Cardiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Siyuan Zha
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, China
| | - Chunli Wang
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, China
| | - Shuyan Chen
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, China.
| | - Fei Wang
- Department of Geriatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, China.
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13
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Ross PD, Guy J, Selfridge J, Kamal B, Bahey N, Tanner KE, Gillingwater TH, Jones RA, Loughrey CM, McCarroll CS, Bailey MES, Bird A, Cobb S. Exclusive expression of MeCP2 in the nervous system distinguishes between brain and peripheral Rett syndrome-like phenotypes. Hum Mol Genet 2018; 25:4389-4404. [PMID: 28173151 PMCID: PMC5886038 DOI: 10.1093/hmg/ddw269] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/22/2022] Open
Abstract
Rett syndrome (RTT) is a severe genetic disorder resulting from mutations in the X-linked MECP2 gene. MeCP2 protein is highly expressed in the nervous system and deficiency in the mouse central nervous system alone recapitulates many features of the disorder. This suggests that RTT is primarily a neurological disorder, although the protein is reportedly widely expressed throughout the body. To determine whether aspects of the RTT phenotype that originate in non-neuronal tissues might have been overlooked, we generated mice in which Mecp2 remains at near normal levels in the nervous system, but is severely depleted elsewhere. Comparison of these mice with wild type and globally MeCP2-deficient mice showed that the majority of RTT-associated behavioural, sensorimotor, gait and autonomic (respiratory and cardiac) phenotypes are absent. Specific peripheral phenotypes were observed, however, most notably hypo-activity, exercise fatigue and bone abnormalities. Our results confirm that the brain should be the primary target for potential RTT therapies, but also strongly suggest that some less extreme but clinically significant aspects of the disorder arise independently of defects in the nervous system.
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Affiliation(s)
- Paul D Ross
- Institute of Neuroscience and Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Jacky Guy
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Edinburgh, UK
| | - Jim Selfridge
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Edinburgh, UK
| | - Bushra Kamal
- Institute of Neuroscience and Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Noha Bahey
- Institute of Neuroscience and Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.,Histology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | | | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Ross A Jones
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Christopher M Loughrey
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK and
| | - Charlotte S McCarroll
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK and
| | - Mark E S Bailey
- School of Life Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Edinburgh, UK
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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14
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Bhattacherjee A, Winter MK, Eggimann LS, Mu Y, Gunewardena S, Liao Z, Christianson JA, Smith PG. Motor, Somatosensory, Viscerosensory and Metabolic Impairments in a Heterozygous Female Rat Model of Rett Syndrome. Int J Mol Sci 2017; 19:ijms19010097. [PMID: 29286317 PMCID: PMC5796047 DOI: 10.3390/ijms19010097] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 12/12/2022] Open
Abstract
Rett Syndrome (RTT), an autism-related disorder caused by mutation of the X-linked Methyl CpG-binding Protein 2 (MECP2) gene, is characterized by severe cognitive and intellectual deficits. While cognitive deficits are well-documented in humans and rodent models, impairments of sensory, motor and metabolic functions also occur but remain poorly understood. To better understand non-cognitive deficits in RTT, we studied female rats heterozygous for Mecp2 mutation (Mecp2−/x); unlike commonly used male Mecp2−/y rodent models, this more closely approximates human RTT where males rarely survive. Mecp2−/x rats showed rapid, progressive decline of motor coordination through six months of age as assessed by rotarod performance, accompanied by deficits in gait and posture. Mecp2−/x rats were hyper-responsive to noxious pressure and cold, but showed visceral hyposensitivity when tested by colorectal distension. Mecp2−/x rats ate less, drank more, and had more body fat resulting in increased weight gain. Our findings reveal an array of progressive non-cognitive deficits in this rat model that are likely to contribute to the compromised quality of life that characterizes RTT.
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Affiliation(s)
- Aritra Bhattacherjee
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Michelle K Winter
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Linda S Eggimann
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Ying Mu
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Sumedha Gunewardena
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Zhaohui Liao
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Julie A Christianson
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Peter G Smith
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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15
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Pacheco NL, Heaven MR, Holt LM, Crossman DK, Boggio KJ, Shaffer SA, Flint DL, Olsen ML. RNA sequencing and proteomics approaches reveal novel deficits in the cortex of Mecp2-deficient mice, a model for Rett syndrome. Mol Autism 2017; 8:56. [PMID: 29090078 PMCID: PMC5655833 DOI: 10.1186/s13229-017-0174-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/02/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MeCP2. Much of our understanding of MeCP2 function is derived from transcriptomic studies with the general assumption that alterations in the transcriptome correlate with proteomic changes. Advances in mass spectrometry-based proteomics have facilitated recent interest in the examination of global protein expression to better understand the biology between transcriptional and translational regulation. METHODS We therefore performed the first comprehensive transcriptome-proteome comparison in a RTT mouse model to elucidate RTT pathophysiology, identify potential therapeutic targets, and further our understanding of MeCP2 function. The whole cortex of wild-type and symptomatic RTT male littermates (n = 4 per genotype) were analyzed using RNA-sequencing and data-independent acquisition liquid chromatography tandem mass spectrometry. Ingenuity® Pathway Analysis was used to identify significantly affected pathways in the transcriptomic and proteomic data sets. RESULTS Our results indicate these two "omics" data sets supplement one another. In addition to confirming previous works regarding mRNA expression in Mecp2-deficient animals, the current study identified hundreds of novel protein targets. Several selected protein targets were validated by Western blot analysis. These data indicate RNA metabolism, proteostasis, monoamine metabolism, and cholesterol synthesis are disrupted in the RTT proteome. Hits common to both data sets indicate disrupted cellular metabolism, calcium signaling, protein stability, DNA binding, and cytoskeletal cell structure. Finally, in addition to confirming disrupted pathways and identifying novel hits in neuronal structure and synaptic transmission, our data indicate aberrant myelination, inflammation, and vascular disruption. Intriguingly, there is no evidence of reactive gliosis, but instead, gene, protein, and pathway analysis suggest astrocytic maturation and morphological deficits. CONCLUSIONS This comparative omics analysis supports previous works indicating widespread CNS dysfunction and may serve as a valuable resource for those interested in cellular dysfunction in RTT.
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Affiliation(s)
- Natasha L. Pacheco
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
| | - Michael R. Heaven
- Vulcan Analytical, LLC, 1500 1st Ave. North, Birmingham, AL 35203 USA
| | - Leanne M. Holt
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
| | - David K. Crossman
- UAB Heflin Center for Genomic Science, Department of Genetics, University of Alabama at Birmingham, Kaul 424A, 1720 2nd Ave. South, Birmingham, AL 35294 USA
| | - Kristin J. Boggio
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Scott A. Shaffer
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Daniel L. Flint
- Luxumbra Strategic Research, LLC, 1331 South Eads St, Arlington, VA 22202 USA
| | - Michelle L. Olsen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
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16
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Hu J, Shen T, Xie J, Wang S, He Y, Zhu F. Curcumin modulates covalent histone modification and TIMP1 gene activation to protect against vascular injury in a hypertension rat model. Exp Ther Med 2017; 14:5896-5902. [PMID: 29285138 PMCID: PMC5740590 DOI: 10.3892/etm.2017.5318] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/06/2017] [Indexed: 01/05/2023] Open
Abstract
Hypertension is a leading risk factor for morbidity and mortality. Previous studies have reported that curcumin has anti-oxidation and anti-aging effects and inhibits histone deacetylase activity. However, it is still unclear whether curcumin could protect against vascular injury induced by hypertension. Thus, the current study examined the therapeutic effects and mechanism of curcumin on vascular injury induced by hypertension in spontaneous hypertensive rats (SHRs). The present study revealed that curcumin may improve vascular structure and attenuate coronary artery pathology. Moderate doses (~50 mg) of curcumin were most effective in treating coronary artery injury in SHRs. Moreover, the results of immunohistochemical analysis indicated that the expression levels of histone deacetylase 1 (HDAC1), matrix metalloproteinase-2 (MMP-2) and transforming growth factor β (TGFβ) decreased in the curcumin treatment group, compared with the non-treated group or the negative control group. However, the expression of tissue inhibitor of metalloproteinase 1 (TIMP1) did not visibly decrease. Furthermore, chromatin immunoprecipitation results suggested that curcumin was capable of promoting the transcription activation of TIMP1 through suppressing HDAC1 expression and increasing histone H3 acetylation at the TIMP1 promoter region in SHRs. In conclusion, curcumin could relieve extracellular matrix degradation and interstitial fibrosis induced by hypertension, and lower blood pressure. It could also serve a function in improving vascular structure through inhibiting the expression of HDAC1, thereby promoting TIMP1 transcription activation and suppressing the expression of MMP-2 and TGFβ.
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Affiliation(s)
- Jun Hu
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
| | - Tingting Shen
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
| | - Jun Xie
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
| | - Siyang Wang
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
| | - Yue He
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
| | - Fu Zhu
- Xuhui Central Hospital, Shanghai Clinical Research Center, China Academy of Sciences, Shanghai 200031, P.R. China
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17
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Leonard H, Cobb S, Downs J. Clinical and biological progress over 50 years in Rett syndrome. Nat Rev Neurol 2016; 13:37-51. [PMID: 27934853 DOI: 10.1038/nrneurol.2016.186] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Jenny Downs
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
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18
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Plant polyphenols as natural drugs for the management of Down syndrome and related disorders. Neurosci Biobehav Rev 2016; 71:865-877. [DOI: 10.1016/j.neubiorev.2016.10.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/17/2016] [Accepted: 10/21/2016] [Indexed: 01/11/2023]
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19
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Ehrhart F, Coort SLM, Cirillo E, Smeets E, Evelo CT, Curfs LMG. Rett syndrome - biological pathways leading from MECP2 to disorder phenotypes. Orphanet J Rare Dis 2016; 11:158. [PMID: 27884167 PMCID: PMC5123333 DOI: 10.1186/s13023-016-0545-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is a rare disease but still one of the most abundant causes for intellectual disability in females. Typical symptoms are onset at month 6-18 after normal pre- and postnatal development, loss of acquired skills and severe intellectual disability. The type and severity of symptoms are individually highly different. A single mutation in one gene, coding for methyl-CpG-binding protein 2 (MECP2), is responsible for the disease. The most important action of MECP2 is regulating epigenetic imprinting and chromatin condensation, but MECP2 influences many different biological pathways on multiple levels although the molecular pathways from gene to phenotype are currently not fully understood. In this review the known changes in metabolite levels, gene expression and biological pathways in RTT are summarized, discussed how they are leading to some characteristic RTT phenotypes and therefore the gaps of knowledge are identified. Namely, which phenotypes have currently no mechanistic explanation leading back to MECP2 related pathways? As a result of this review the visualization of the biologic pathways showing MECP2 up- and downstream regulation was developed and published on WikiPathways which will serve as template for future omics data driven research. This pathway driven approach may serve as a use case for other rare diseases, too.
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Affiliation(s)
- Friederike Ehrhart
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands. .,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
| | - Susan L M Coort
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Elisa Cirillo
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Eric Smeets
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Chris T Evelo
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Leopold M G Curfs
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
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20
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Janc OA, Hüser MA, Dietrich K, Kempkes B, Menzfeld C, Hülsmann S, Müller M. Systemic Radical Scavenger Treatment of a Mouse Model of Rett Syndrome: Merits and Limitations of the Vitamin E Derivative Trolox. Front Cell Neurosci 2016; 10:266. [PMID: 27895554 PMCID: PMC5109403 DOI: 10.3389/fncel.2016.00266] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/01/2016] [Indexed: 12/21/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder typically arising from spontaneous mutations in the X-chromosomal methyl-CpG binding protein 2 (MECP2) gene. The almost exclusively female Rett patients show an apparently normal development during their first 6-18 months of life. Subsequently, cognitive- and motor-impairment, hand stereotypies, loss of learned skills, epilepsy and irregular breathing manifest. Early mitochondrial impairment and oxidative challenge are considered to facilitate disease progression. Along this line, we recently confirmed in vitro that acute treatment with the vitamin E-derivative Trolox dampens neuronal hyperexcitability, reinstates synaptic plasticity, ameliorates cellular redox balance and improves hypoxia tolerance in male MeCP2-deficient (Mecp2-/y ) mouse hippocampus. Pursuing these promising findings, we performed a preclinical study to define the merit of systemic Trolox administration. Blinded, placebo-controlled in vivo treatment of male mice started at postnatal day (PD) 10-11 and continued for ~40 days. Compounds (vehicle only, 10 mg/kg or 40 mg/kg Trolox) were injected intraperitoneally every 48 h. Detailed phenotyping revealed that in Mecp2-/y mice, blood glucose levels, lipid peroxidation, synaptic short-term plasticity, hypoxia tolerance and certain forms of environmental exploration were improved by Trolox. Yet, body weight and size, motor function and the rate and regularity of breathing did not improve. In conclusion, in vivo Trolox treatment partially ameliorated a subset of symptoms of the complex Rett phenotype, thereby confirming a partial merit of the vitamin E-derivative based pharmacotherapy. Yet, it also became evident that frequent animal handling and the route of drug administration are critical issues to be optimized in future trials.
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Affiliation(s)
- Oliwia A Janc
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Marc A Hüser
- Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Germany
| | - Katharina Dietrich
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Belinda Kempkes
- Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Germany
| | - Christiane Menzfeld
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Swen Hülsmann
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Klinik für Anästhesiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Michael Müller
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
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21
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Pecorelli A, Cervellati C, Cortelazzo A, Cervellati F, Sticozzi C, Mirasole C, Guerranti R, Trentini A, Zolla L, Savelli V, Hayek J, Valacchi G. Proteomic analysis of 4-hydroxynonenal and nitrotyrosine modified proteins in RTT fibroblasts. Int J Biochem Cell Biol 2016; 81:236-245. [PMID: 27495376 DOI: 10.1016/j.biocel.2016.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/27/2016] [Accepted: 08/01/2016] [Indexed: 11/19/2022]
Abstract
Rett syndrome (RTT) is a pervasive developmental disorder, primarily affecting girls with a prevalence of 1 in every 10,000 births. A clear etiological factor present in more than 90% of classical RTT cases is the mutation of the gene encoding methyl-CpG-binding protein 2 (MECP2). Recent work from our group was able to shown a systemic oxidative stress (OxS) in these patients that correlates with the gravity of the clinical features. Using freshly isolated skin fibroblasts from RTT patients and healthy subjects, we have performed a two-dimensional gel electrophoresis in order to evidence the oxidative modifications of proteins with special focus on the formation of protein adducts with 4-hydroxynonenal (4-HNE PAs)-a major secondary product of lipid peroxidation- and Nitrotyrosine, a marker derived from the biochemical interaction of nitric oxide (NO) or nitric oxide-derived secondary products with reactive oxygen species (ROS). Then, oxidatively modified spots were identified by mass spectrometry, LC-ESI-CID-MS/MS. Our results showed that 15 protein spots presented 4-HNE PAs and/or nitrotyrosine adducts in fibroblasts proteome from RTT patients compared to healthy control cells. Post-translationally modified proteins were related to several functional categories, in particular to cytoskeleton structure and protein folding. In addition, clear upregulated expression of the inducible NO synthase (iNOS) with high nitrite levels were observed in RTT fibroblasts, justifying the increased nitrotyrosine protein modifications. The present work describes not only the proteomic profile in RTT fibroblasts, but also identifies the modified proteins by 4-HNE and nitrotyrosine. Of note, for the first time, it appears that a dysregulation of NO pathway can be associated to RTT pathophysiology. In conclusion, the evidence of a wide range of proteins able to forms adducts with 4-HNE, Nitrotyrosine or with both confirms the possible alteration of several aspects of cellular functions that well correlates to the complex clinical features of RTT patients.
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Affiliation(s)
- Alessandra Pecorelli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
| | - Carlo Cervellati
- Department of Biomedical and Specialist Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Alessio Cortelazzo
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Franco Cervellati
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Claudia Sticozzi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Cristiana Mirasole
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Roberto Guerranti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Alessandro Trentini
- Department of Biomedical and Specialist Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Lello Zolla
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Vinno Savelli
- Department of Medical, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Joussef Hayek
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
| | - Giuseppe Valacchi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
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22
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Cobolli Gigli C, Scaramuzza L, Gandaglia A, Bellini E, Gabaglio M, Parolaro D, Kilstrup-Nielsen C, Landsberger N, Bedogni F. MeCP2 Related Studies Benefit from the Use of CD1 as Genetic Background. PLoS One 2016; 11:e0153473. [PMID: 27097329 PMCID: PMC4838291 DOI: 10.1371/journal.pone.0153473] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 03/29/2016] [Indexed: 12/20/2022] Open
Abstract
MECP2 mutations cause a number of neurological disorders of which Rett syndrome (RTT) represents the most thoroughly analysed condition. Many Mecp2 mouse models have been generated through the years; their validity is demonstrated by the presence of a broad spectrum of phenotypes largely mimicking those manifested by RTT patients. These mouse models, between which the C57BL/6 Mecp2tm1.1Bird strain probably represents the most used, enabled to disclose much of the roles of Mecp2. However, small litters with little viability and poor maternal care hamper the maintenance of the colony, thus limiting research on such animals. For this reason, past studies often used Mecp2 mouse models on mixed genetic backgrounds, thus opening questions on whether modifier genes could be responsible for at least part of the described effects. To verify this possibility, and facilitate the maintenance of the Mecp2 colony, we transferred the Mecp2tm1.1Bird allele on the stronger CD1 background. The CD1 strain is easier to maintain and largely recapitulates the phenotypes already described in Mecp2-null mice. We believe that this mouse model will foster the research on RTT.
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Affiliation(s)
- Clementina Cobolli Gigli
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Linda Scaramuzza
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Anna Gandaglia
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Elisa Bellini
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Marina Gabaglio
- Department of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio, Italy
| | - Daniela Parolaro
- Department of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio, Italy
- ZardiGori Foundation, Milan, Italy
| | | | - Nicoletta Landsberger
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, University of Milan, L.I.T.A., Segrate, Italy
- * E-mail: (NL); (FB)
| | - Francesco Bedogni
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
- * E-mail: (NL); (FB)
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Filosa S, Pecorelli A, D'Esposito M, Valacchi G, Hajek J. Exploring the possible link between MeCP2 and oxidative stress in Rett syndrome. Free Radic Biol Med 2015; 88:81-90. [PMID: 25960047 DOI: 10.1016/j.freeradbiomed.2015.04.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 01/27/2023]
Abstract
Rett syndrome (RTT, MIM 312750) is a rare and orphan progressive neurodevelopmental disorder affecting girls almost exclusively, with a frequency of 1/15,000 live births of girls. The disease is characterized by a period of 6 to 18 months of apparently normal neurodevelopment, followed by early neurological regression, with a progressive loss of acquired cognitive, social, and motor skills. RTT is known to be caused in 95% of the cases by sporadic de novo loss-of-function mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene encoding methyl-CpG binding protein 2 (MeCP2), a nuclear protein able to regulate gene expression. Despite almost two decades of research into the functions and role of MeCP2, little is known about the mechanisms leading from MECP2 mutation to the disease. Oxidative stress (OS) is involved in the pathogenic mechanisms of several neurodevelopmental and neurodegenerative disorders, although in many cases it is not clear whether OS is a cause or a consequence of the pathology. Fairly recently, the presence of a systemic OS has been demonstrated in RTT patients with a strong correlation with the patients' clinical status. The link between MECP2 mutation and the redox imbalance found in RTT is not clear. Animal studies have suggested a possible direct correlation between Mecp2 mutation and increased OS levels. In addition, the restoration of Mecp2 function in astrocytes significantly improves the developmental outcome of Mecp2-null mice and reexpression of Mecp2 gene in the brain of null mice restored oxidative damage, suggesting that Mecp2 loss of function can be involved in oxidative brain damage. Starting from the evidence that oxidative damage in the brain of Mecp2-null mice precedes the onset of symptoms, we evaluated whether, based on the current literature, the dysfunctions described in RTT could be a consequence or, in contrast, could be caused by OS. We also analyzed whether therapies that at least partially treated some RTT symptoms can play a role in defense against OS. At this stage we can propose that OS could be one of the main causes of the dysfunctions observed in RTT. In addition, the major part of the therapies recommended to alleviate RTT symptoms have been shown to interfere with oxidative homeostasis, suggesting that MeCP2 could somehow be involved in the protection of the brain from OS.
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Affiliation(s)
- Stefania Filosa
- Institute of Biosciences and BioResources-CNR, UOS Naples, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Alessandra Pecorelli
- Child Neuropsychiatry Unit, University General Hospital, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A. Buzzati-Traverso"-CNR, Naples, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Giuseppe Valacchi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Department of Food and Nutrition, Kyung Hee University, Seoul, South Korea.
| | - Joussef Hajek
- Child Neuropsychiatry Unit, University General Hospital, Azienda Ospedaliera Universitaria Senese, Siena, Italy
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Liang Z, Xie W, Wu R, Geng H, Zhao L, Xie C, Li X, Zhu M, Zhu W, Zhu J, Huang C, Ma X, Wu J, Geng S, Zhong C, Han H. Inhibition of tobacco smoke-induced bladder MAPK activation and epithelial-mesenchymal transition in mice by curcumin. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:4503-4513. [PMID: 26191140 PMCID: PMC4503012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/15/2015] [Indexed: 06/04/2023]
Abstract
Tobacco smoke (TS) has been shown to cause bladder cancer. Epithelial-mesenchymal transition (EMT) is a crucial pathophysiological process in cancer development. MAPK pathways play central roles in tumorigenesis including EMT process. Curcumin is a promising chemopreventive agent for several types of cancers. In the present study we investigated the effects of TS on MAPK pathway activation and EMT alterations in the bladder of mice, and the preventive effect of curcumin was further examined. Results showed that exposure of mice to TS for 12 weeks resulted in activation of ERK1/2, JNK, p38 and ERK5 MAPK pathways as well as AP-1 proteins in bladder. TS reduced mRNA and protein expression levels of epithelial markers E-cadherin and ZO-1, while mRNA and protein expression levels of the mesenchymal markers vimentin and N-cadherin were increased. Curcumin treatment effectively attenuated TS-triggered activation of ERK1/2, JNK and p38 MAPK pathways, AP-1 proteins and EMT alterations in bladder tissue. These results suggest the protective effects of curcumin in TS-induced MAPK activation and EMT, thus providing new insights into the chemoprevention of TS-associated bladder cancer.
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Affiliation(s)
- Zhaofeng Liang
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Wei Xie
- Institute of Food Safety and Assessment, Jiangsu Provincial Center for Disease Control and PreventionNanjing 211166, China
| | - Rui Wu
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Hao Geng
- Department of Urology, The Second Affiliated Hospital of Anhui Medical UniversityHefei 230032, China
| | - Li Zhao
- Department of Urology, The Second Affiliated Hospital of Anhui Medical UniversityHefei 230032, China
| | - Chunfeng Xie
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Xiaoting Li
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Mingming Zhu
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Weiwei Zhu
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Jianyun Zhu
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Cong Huang
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Xiao Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Jieshu Wu
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Shanshan Geng
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Caiyun Zhong
- Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical UniversityNanjing 211166, China
| | - Hongyu Han
- Department of Clinical Nutrition, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South ChinaGuangzhou 510060, China
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25
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Abstract
RTT (Rett syndrome) is a severe progressive neurodevelopmental disorder with a monogenetic cause, but complex and multifaceted clinical appearance. Compelling evidence suggests that mitochondrial alterations and aberrant redox homoeostasis result in oxidative challenge. Yet, compared with other severe neuropathologies, RTT is not associated with marked neurodegeneration, but rather a chemical imbalance and miscommunication of neuronal elements. Different pharmacotherapies mediate partial improvement of conditions in RTT, and also antioxidants or compounds improving mitochondrial function may be of potential merit. In the present paper, we summarize findings from patients and transgenic mice that point towards the nature of RTT as a mitochondrial disease. Also, open questions are addressed that require clarification to fully understand and successfully target the associated cellular redox imbalance.
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Inflammatory lung disease in Rett syndrome. Mediators Inflamm 2014; 2014:560120. [PMID: 24757286 PMCID: PMC3976920 DOI: 10.1155/2014/560120] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/06/2014] [Accepted: 01/14/2014] [Indexed: 12/30/2022] Open
Abstract
Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly linked to mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Respiratory dysfunction, historically credited to brainstem immaturity, represents a major challenge in RTT. Our aim was to characterize the relationships between pulmonary gas exchange abnormality (GEA), upper airway obstruction, and redox status in patients with typical RTT (n = 228) and to examine lung histology in a Mecp2-null mouse model of the disease. GEA was detectable in ~80% (184/228) of patients versus ~18% of healthy controls, with “high” (39.8%) and “low” (34.8%) patterns dominating over “mixed” (19.6%) and “simple mismatch” (5.9%) types. Increased plasma levels of non-protein-bound iron (NPBI), F2-isoprostanes (F2-IsoPs), intraerythrocyte NPBI (IE-NPBI), and reduced and oxidized glutathione (i.e., GSH and GSSG) were evidenced in RTT with consequently decreased GSH/GSSG ratios. Apnea frequency/severity was positively correlated with IE-NPBI, F2-IsoPs, and GSSG and negatively with GSH/GSSG ratio. A diffuse inflammatory infiltrate of the terminal bronchioles and alveoli was evidenced in half of the examined Mecp2-mutant mice, well fitting with the radiological findings previously observed in RTT patients. Our findings indicate that GEA is a key feature of RTT and that terminal bronchioles are a likely major target of the disease.
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27
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Abstract
Rett syndrome (RTT) is a severe and progressive neurological disorder, which mainly affects young females. Mutations of the methyl-CpG binding protein 2 (MECP2) gene are the most prevalent cause of classical RTT cases. MECP2 mutations or altered expression are also associated with a spectrum of neurodevelopmental disorders such as autism spectrum disorders with recent links to fetal alcohol spectrum disorders. Collectively, MeCP2 relation to these neurodevelopmental disorders highlights the importance of understanding the molecular mechanisms by which MeCP2 impacts brain development, mental conditions, and compromised brain function. Since MECP2 mutations were discovered to be the primary cause of RTT, a significant progress has been made in the MeCP2 research, with respect to the expression, function and regulation of MeCP2 in the brain and its contribution in RTT pathogenesis. To date, there have been intensive efforts in designing effective therapeutic strategies for RTT benefiting from mouse models and cells collected from RTT patients. Despite significant progress in MeCP2 research over the last few decades, there is still a knowledge gap between the in vitro and in vivo research findings and translating these findings into effective therapeutic interventions in human RTT patients. In this review, we will provide a synopsis of Rett syndrome as a severe neurological disorder and will discuss the role of MeCP2 in RTT pathophysiology.
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28
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Janc OA, Müller M. The free radical scavenger Trolox dampens neuronal hyperexcitability, reinstates synaptic plasticity, and improves hypoxia tolerance in a mouse model of Rett syndrome. Front Cell Neurosci 2014; 8:56. [PMID: 24605086 PMCID: PMC3932407 DOI: 10.3389/fncel.2014.00056] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/06/2014] [Indexed: 11/13/2022] Open
Abstract
Rett syndrome (RS) causes severe cognitive impairment, loss of speech, epilepsy, and breathing disturbances with intermittent hypoxia. Also mitochondria are affected; a subunit of respiratory complex III is dysregulated, the inner mitochondrial membrane is leaking protons, and brain ATP levels seem reduced. Our recent assessment of mitochondrial function in MeCP2 (methyl-CpG-binding protein 2)-deficient mouse (Mecp2-/y) hippocampus confirmed early metabolic alterations, an increased oxidative burden, and a more vulnerable cellular redox balance. As these changes may contribute to the manifestation of symptoms and disease progression, we now evaluated whether free radical scavengers are capable of improving neuronal and mitochondrial function in RS. Acute hippocampal slices of adult mice were incubated with the vitamin E derivative Trolox for 3–5 h. In Mecp2-/y slices this treatment dampened neuronal hyperexcitability, improved synaptic short-term plasticity, and fully restored synaptic long-term potentiation (LTP). Furthermore, Trolox specifically attenuated the increased hypoxia susceptibility of Mecp2-/y slices. Also, the anticonvulsive effects of Trolox were assessed, but the severity of 4-aminopyridine provoked seizure-like discharges was not significantly affected. Adverse side effects of Trolox on mitochondria can be excluded, but clear indications for an improvement of mitochondrial function were not found. Since several ion-channels and neurotransmitter receptors are redox modulated, the mitochondrial alterations and the associated oxidative burden may contribute to the neuronal dysfunction in RS. We confirmed in Mecp2-/y hippocampus that Trolox dampens neuronal hyperexcitability, reinstates synaptic plasticity, and improves the hypoxia tolerance. Therefore, radical scavengers are promising compounds for the treatment of neuronal dysfunction in RS and deserve further detailed evaluation.
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Affiliation(s)
- Oliwia A Janc
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Georg-August-Universität Göttingen Göttingen, Germany ; Zentrum für Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin, Georg-August-Universität Göttingen Göttingen, Germany
| | - Michael Müller
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Georg-August-Universität Göttingen Göttingen, Germany ; Zentrum für Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin, Georg-August-Universität Göttingen Göttingen, Germany
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