1
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Antón R, Treviño MÁ, Pantoja-Uceda D, Félix S, Babu M, Cabrita EJ, Zweckstetter M, Tinnefeld P, Vera AM, Oroz J. Alternative low-populated conformations prompt phase transitions in polyalanine repeat expansions. Nat Commun 2024; 15:1925. [PMID: 38431667 PMCID: PMC10908835 DOI: 10.1038/s41467-024-46236-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 02/19/2024] [Indexed: 03/05/2024] Open
Abstract
Abnormal trinucleotide repeat expansions alter protein conformation causing malfunction and contribute to a significant number of incurable human diseases. Scarce structural insights available on disease-related homorepeat expansions hinder the design of effective therapeutics. Here, we present the dynamic structure of human PHOX2B C-terminal fragment, which contains the longest polyalanine segment known in mammals. The major α-helical conformation of the polyalanine tract is solely extended by polyalanine expansions in PHOX2B, which are responsible for most congenital central hypoventilation syndrome cases. However, polyalanine expansions in PHOX2B additionally promote nascent homorepeat conformations that trigger length-dependent phase transitions into solid condensates that capture wild-type PHOX2B. Remarkably, HSP70 and HSP90 chaperones specifically seize PHOX2B alternative conformations preventing phase transitions. The precise observation of emerging polymorphs in expanded PHOX2B postulates unbalanced phase transitions as distinct pathophysiological mechanisms in homorepeat expansion diseases, paving the way towards the search of therapeutics modulating biomolecular condensates in central hypoventilation syndrome.
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Affiliation(s)
- Rosa Antón
- Instituto de Química Física Blas Cabrera (IQF), CSIC, E-28006, Madrid, Spain
| | - Miguel Á Treviño
- Instituto de Química Física Blas Cabrera (IQF), CSIC, E-28006, Madrid, Spain
| | - David Pantoja-Uceda
- Instituto de Química Física Blas Cabrera (IQF), CSIC, E-28006, Madrid, Spain
| | - Sara Félix
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516, Caparica, Portugal
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516, Caparica, Portugal
| | - María Babu
- German Center for Neurodegenerative Diseases (DZNE), 37075, Göttingen, Germany
| | - Eurico J Cabrita
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516, Caparica, Portugal
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516, Caparica, Portugal
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), 37075, Göttingen, Germany
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, München, 81377, Germany
| | - Andrés M Vera
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, München, 81377, Germany
| | - Javier Oroz
- Instituto de Química Física Blas Cabrera (IQF), CSIC, E-28006, Madrid, Spain.
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2
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Surma S, Sahebkar A, Urbański J, Penson PE, Banach M. Curcumin - The Nutraceutical With Pleiotropic Effects? Which Cardiometabolic Subjects Might Benefit the Most? Front Nutr 2022; 9:865497. [PMID: 35662932 PMCID: PMC9159377 DOI: 10.3389/fnut.2022.865497] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/07/2022] [Indexed: 12/23/2022] Open
Abstract
Despite continuous advances in pharmacotherapy, atherosclerotic cardiovascular disease remains the world's leading killer. Atherosclerosis relates not only to an increased level of cholesterol, but involves the development of atherosclerotic plaques, which are formed as a result of processes including inflammation and oxidative stress. Therefore, in addition to the classical risk factors for ASCVD (such as type 2 diabetes, overweight, obesity, hypertension and metabolic syndrome), residual risk factors such as inflammation and oxidative stress should also be reduced. The most important intervention in ASCVD is prevention, which includes promoting a healthy diet based on products of natural origin. Curcumin, which is often present in the diet, has been demonstrate to confer several benefits to health. It has been shown in numerous clinical trials that curcumin exhibited anti-diabetic, lipid-lowering, antihypertensive, antioxidant and anti-inflammatory effects, as well as promoting weight loss. All this means that curcumin has a comprehensive impact on the most important risk factors of ASCVD and may be a beneficial support in the treatment of these diseases. Recently, it has also been shown that curcumin may have a beneficial effect on the course of SARS-CoV-2 infection and might be helpful in the prevention of long-COVID complications. The aim of this review is to summarize the current knowledge regarding the safety and efficacy of curcumin in the prevention and treatment of cardiometabolic diseases.
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Affiliation(s)
- Stanisław Surma
- Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
- Club of Young Hypertensiologists, Polish Society of Hypertension, Gdańsk, Poland
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Peter E. Penson
- Clinical Pharmacy and Therapeutics Research Group, School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom
- Liverpool Centre for Cardiovascular Science, Liverpool, United Kingdom
| | - Maciej Banach
- Department of Preventive Cardiology and Lipidology, Medical University of Lodz, Łódź, Poland
- Cardiovascular Research Centre, University of Zielona Gora, Zielona Góra, Poland
- Department of Cardiology and Adult Congenital Heart Diseases, Polish Mother's Memorial Hospital Research Institute (PMMHRI), Łódź, Poland
- *Correspondence: Maciej Banach
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3
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Peruzzi M, Ramazzotti M, Damiano R, Vasarri M, la Marca G, Arzilli C, Piumelli R, Nassi N, Degl'Innocenti D. Urinary Biomarkers as a Proxy for Congenital Central Hypoventilation Syndrome Patient Follow-Up. Antioxidants (Basel) 2022; 11:antiox11050929. [PMID: 35624794 PMCID: PMC9138029 DOI: 10.3390/antiox11050929] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/25/2022] [Accepted: 05/06/2022] [Indexed: 12/25/2022] Open
Abstract
Congenital Central Hypoventilation Syndrome (CCHS) is a rare genetic disorder of the autonomic nervous system and in particular of the respiratory control during sleep. No drug therapy is, to date, available; therefore, the survival of these patients depends on lifelong ventilatory support during sleep. Reactive oxygen species (ROS)-induced oxidative stress is a recognized risk factor involved in the pathogenesis of several chronic diseases. Therefore, monitoring systemic oxidative stress could provide important insights into CCHS outcomes. Because ROS-induced oxidative products are excreted as stable metabolites in urine, we performed an HPLC-MS/MS analysis for the quantitative determination of the three main representative oxidative biomarkers (i.e., diY, MDA, and 8-OHdG) in the urine of CCHS patients. Higher levels of urinary MDA were found in CCHS patients compared with age-matched control subjects. The noteworthy finding is the identification of urinary MDA as relevant biomarker of systemic oxidative status in CCHS patients. This study is a concise and smart communication about the impact that oxidative stress has in CCHS, and suggests the monitoring of urinary MDA levels as a useful tool for the management of these patients.
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Affiliation(s)
- Marta Peruzzi
- Sleep Breathing Disorders and SIDS Centre, A. Meyer Children’s Hospital, 50134 Florence, Italy; (M.P.); (C.A.); (R.P.); (N.N.)
| | - Matteo Ramazzotti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy; (M.R.); (R.D.); (M.V.); (G.l.M.)
| | - Roberta Damiano
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy; (M.R.); (R.D.); (M.V.); (G.l.M.)
- Newborn Screening, Biochemistry and Pharmacology Laboratory, A. Meyer Children’s Hospital, 50134 Florence, Italy
| | - Marzia Vasarri
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy; (M.R.); (R.D.); (M.V.); (G.l.M.)
| | - Giancarlo la Marca
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy; (M.R.); (R.D.); (M.V.); (G.l.M.)
- Newborn Screening, Biochemistry and Pharmacology Laboratory, A. Meyer Children’s Hospital, 50134 Florence, Italy
| | - Cinzia Arzilli
- Sleep Breathing Disorders and SIDS Centre, A. Meyer Children’s Hospital, 50134 Florence, Italy; (M.P.); (C.A.); (R.P.); (N.N.)
| | - Raffaele Piumelli
- Sleep Breathing Disorders and SIDS Centre, A. Meyer Children’s Hospital, 50134 Florence, Italy; (M.P.); (C.A.); (R.P.); (N.N.)
| | - Niccolò Nassi
- Sleep Breathing Disorders and SIDS Centre, A. Meyer Children’s Hospital, 50134 Florence, Italy; (M.P.); (C.A.); (R.P.); (N.N.)
| | - Donatella Degl'Innocenti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy; (M.R.); (R.D.); (M.V.); (G.l.M.)
- Correspondence:
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4
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Ceccherini I, Kurek KC, Weese-Mayer DE. Developmental disorders affecting the respiratory system: CCHS and ROHHAD. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:53-91. [PMID: 36031316 DOI: 10.1016/b978-0-323-91532-8.00005-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) and Congenital Central Hypoventilation Syndrome (CCHS) are ultra-rare distinct clinical disorders with overlapping symptoms including altered respiratory control and autonomic regulation. Although both disorders have been considered for decades to be on the same spectrum with necessity of artificial ventilation as life-support, recent acquisition of specific knowledge concerning the genetic basis of CCHS coupled with an elusive etiology for ROHHAD have definitely established that the two disorders are different. CCHS is an autosomal dominant neurocristopathy characterized by alveolar hypoventilation resulting in hypoxemia/hypercarbia and features of autonomic nervous system dysregulation (ANSD), with presentation typically in the newborn period. It is caused by paired-like homeobox 2B (PHOX2B) variants, with known genotype-phenotype correlation but pathogenic mechanism(s) are yet unknown. ROHHAD is characterized by rapid weight gain, followed by hypothalamic dysfunction, then hypoventilation followed by ANSD, in seemingly normal children ages 1.5-7 years. Postmortem neuroanatomical studies, thorough clinical characterization, pathophysiological assessment, and extensive genetic inquiry have failed to identify a cause attributable to a traditional genetic basis, somatic mosaicism, epigenetic mechanism, environmental trigger, or other. To find the key to the ROHHAD pathogenesis and to improve its clinical management, in the present chapter, we have carefully compared CCHS and ROHHAD.
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Affiliation(s)
- Isabella Ceccherini
- Laboratory of Genetics and Genomics of Rare Diseases, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Kyle C Kurek
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Debra E Weese-Mayer
- Division of Autonomic Medicine, Department of Pediatrics, Ann & Robert H Lurie Children's Hospital of Chicago and Stanley Manne Children's Research Institute; and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.
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5
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Di Lascio S, Benfante R, Cardani S, Fornasari D. Research Advances on Therapeutic Approaches to Congenital Central Hypoventilation Syndrome (CCHS). Front Neurosci 2021; 14:615666. [PMID: 33510615 PMCID: PMC7835644 DOI: 10.3389/fnins.2020.615666] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital central hypoventilation syndrome (CCHS) is a genetic disorder of neurodevelopment, with an autosomal dominant transmission, caused by heterozygous mutations in the PHOX2B gene. CCHS is a rare disorder characterized by hypoventilation due to the failure of autonomic control of breathing. Until now no curative treatment has been found. PHOX2B is a transcription factor that plays a crucial role in the development (and maintenance) of the autonomic nervous system, and in particular the neuronal structures involved in respiratory reflexes. The underlying pathogenetic mechanism is still unclear, although studies in vivo and in CCHS patients indicate that some neuronal structures may be damaged. Moreover, in vitro experimental data suggest that transcriptional dysregulation and protein misfolding may be key pathogenic mechanisms. This review summarizes latest researches that improved the comprehension of the molecular pathogenetic mechanisms responsible for CCHS and discusses the search for therapeutic intervention in light of the current knowledge about PHOX2B function.
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Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy.,CNR-Institute of Neuroscience, Milan, Italy.,NeuroMi-Milan Center for Neuroscience, University of Milano Bicocca, Milan, Italy
| | - Silvia Cardani
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy.,CNR-Institute of Neuroscience, Milan, Italy
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6
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Trang H, Samuels M, Ceccherini I, Frerick M, Garcia-Teresa MA, Peters J, Schoeber J, Migdal M, Markstrom A, Ottonello G, Piumelli R, Estevao MH, Senecic-Cala I, Gnidovec-Strazisar B, Pfleger A, Porto-Abal R, Katz-Salamon M. Guidelines for diagnosis and management of congenital central hypoventilation syndrome. Orphanet J Rare Dis 2020; 15:252. [PMID: 32958024 PMCID: PMC7503443 DOI: 10.1186/s13023-020-01460-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/03/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Congenital Central Hypoventilation Syndrome (CCHS) is a rare condition characterized by an alveolar hypoventilation due to a deficient autonomic central control of ventilation and a global autonomic dysfunction. Paired-like homeobox 2B (PHOX2B) mutations are found in most of the patients with CCHS. In recent years, the condition has evolved from a life-threatening neonatal onset disorder to include broader and milder clinical presentations, affecting children, adults and families. Genes other than PHOX2B have been found responsible for CCHS in rare cases and there are as yet other unknown genes that may account for the disease. At present, management relies on lifelong ventilatory support and close follow up of dysautonomic progression. BODY: This paper provides a state-of-the-art comprehensive description of CCHS and of the components of diagnostic evaluation and multi-disciplinary management, as well as considerations for future research. CONCLUSION Awareness and knowledge of the diagnosis and management of this rare disease should be brought to a large health community including adult physicians and health carers.
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Affiliation(s)
- Ha Trang
- Hôpital Universitaire Robert Debré, Centre de référence des maladies respiratoires rares, and Université de Paris, Paris, France
| | - Martin Samuels
- Staffordshire Children’s Hospital, Stoke-on-Trent, Staffs and Great Ormond Street Hospital, London, UK
| | - Isabella Ceccherini
- Istituto Giannina Gaslini, UOSD Laboratory of Genetics and Genomics of Rare Diseases, Genoa, Italy
| | - Matthias Frerick
- Department of Pediatrics, Klinikum Dritter Orden, Munich, Germany
| | | | - Jochen Peters
- Department of Pediatrics, Klinikum Dritter Orden, Munich, Germany
| | | | - Marek Migdal
- Department of Anaesthesiology and Intensive care, Children’s Memorial Health Institute, Warsaw, Poland
| | | | | | - Raffaele Piumelli
- Sleep Disordered Breathing and SIDS Center, Meyer Children’s Hospital, Florence, Italy
| | | | - Irena Senecic-Cala
- University Hospital Centre, Department of Pediatrics, Zagreb and School of Medicine, Zagreb, Croatia
| | - Barbara Gnidovec-Strazisar
- University Children’s Hospital, Department of child, adolescent & developmental neurology, University Clinical Centre Ljubljana, Ljubljana, Slovenia
| | - Andreas Pfleger
- Medical University of Graz, Paediatric Pulmonology and Allergology, Graz, Austria
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7
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Pirone L, Caldinelli L, Di Lascio S, Di Girolamo R, Di Gaetano S, Fornasari D, Pollegioni L, Benfante R, Pedone E. Molecular insights into the role of the polyalanine region in mediating PHOX2B aggregation. FEBS J 2019; 286:2505-2521. [PMID: 30955232 DOI: 10.1111/febs.14841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/27/2019] [Accepted: 04/04/2019] [Indexed: 11/26/2022]
Abstract
About 90% of congenital central hypoventilation syndrome (CCHS) patients show polyalanine triplet expansions in the coding region of transcription factor PHOX2B, which renders this protein an intriguing target to understand the insurgence of this syndrome and for the design of a novel therapeutical approach. Consistently with the role of PHOX2B as a transcriptional regulator, it is reasonable that a general transcriptional dysregulation caused by the polyalanine expansion might represent an important mechanism underlying CCHS pathogenesis. Therefore, this study focused on the biochemical characterization of different PHOX2B variants, such as a variant containing the correct C-terminal (20 alanines) stretch, one of the most frequent polyalanine expansions (+7 alanines), and a variant lacking the complete alanine stretch (0 alanines). Comparison of the different variants by a multidisciplinary approach based on different methodologies (including circular dichroism, spectrofluorimetry, light scattering, and Atomic Force Microscopy studies) highlighted the propensity to aggregate for the PHOX2B variant containing the polyalanine expansion (+7-alanines), especially in the presence of DNA, while the 0-alanines variant resembled the protein with the correct polyalanine length. Moreover, and unexpectedly, the formation of fibrils was revealed only for the pathological variant, suggesting a plausible role of such fibrils in the insurgence of CCHS.
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Affiliation(s)
- Luciano Pirone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
| | - Laura Caldinelli
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, Varese, Italy
| | - Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | - Rocco Di Girolamo
- Department of Chemical Sciences, University of Naples Federico II, Italy
| | | | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, Varese, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
- CNR- Neuroscience Institute, Milan, Italy
| | - Emilia Pedone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
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8
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Di Lascio S, Benfante R, Cardani S, Fornasari D. Advances in the molecular biology and pathogenesis of congenital central hypoventilation syndrome—implications for new therapeutic targets. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1540978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
- CNR- Neuroscience Institute, Milan, Italy
| | - Silvia Cardani
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
- CNR- Neuroscience Institute, Milan, Italy
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9
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Coghlan M, Richards E, Shaik S, Rossi P, Vanama RB, Ahmadi S, Petroz C, Crawford M, Maynes JT. Inhalational Anesthetics Induce Neuronal Protein Aggregation and Affect ER Trafficking. Sci Rep 2018; 8:5275. [PMID: 29588456 PMCID: PMC5869676 DOI: 10.1038/s41598-018-23335-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 03/07/2018] [Indexed: 12/27/2022] Open
Abstract
Anesthetic agents have been implicated in the causation of neurological and cognitive deficits after surgery, the exacerbation of chronic neurodegenerative disease, and were recently reported to promote the onset of the neurologic respiratory disease Congenital Central Hypoventilation Syndrome (CCHS), related to misfolding of the transcription factor Phox2B. To study how anesthetic agents could affect neuronal function through alterations to protein folding, we created neuronal cell models emulating the graded disease severity of CCHS. We found that the gas anesthetic isoflurane and the opiate morphine potentiated aggregation and mislocalization of Phox2B variants, similar to that seen in CCHS, and observed transcript and protein level changes consistent with activation of the endoplasmic reticulum (ER) unfolded protein response. Attenuation of ER stress pathways did not result in a correction of Phox2B misfolding, indicating a primary effect of isoflurane on protein structure. We also observed that isoflurane hindered the folding and activity of proteins that rely heavily on ER function, like the CFTR channel. Our results show how anesthetic drugs can alter protein folding and induce ER stress, indicating a mechanism by which these agents may affect neuronal function after surgery.
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Affiliation(s)
- Matthew Coghlan
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Elizabeth Richards
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Sadiq Shaik
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Pablo Rossi
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Ramesh Babu Vanama
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Saumel Ahmadi
- Program in Molecular Medicine, SickKids Research Institute, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
| | - Christelle Petroz
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Mark Crawford
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Anesthesia, University of Toronto, Toronto, Canada
| | - Jason T Maynes
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada. .,Department of Anesthesia, University of Toronto, Toronto, Canada. .,Program in Molecular Medicine, SickKids Research Institute, Toronto, Canada.
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10
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Di Lascio S, Benfante R, Di Zanni E, Cardani S, Adamo A, Fornasari D, Ceccherini I, Bachetti T. Structural and functional differences in PHOX2B frameshift mutations underlie isolated or syndromic congenital central hypoventilation syndrome. Hum Mutat 2017; 39:219-236. [PMID: 29098737 PMCID: PMC5846889 DOI: 10.1002/humu.23365] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/24/2017] [Accepted: 10/29/2017] [Indexed: 12/13/2022]
Abstract
Heterozygous mutations in the PHOX2B gene are causative of congenital central hypoventilation syndrome (CCHS), a neurocristopathy characterized by defective autonomic control of breathing due to the impaired differentiation of neural crest cells. Among PHOX2B mutations, polyalanine (polyAla) expansions are almost exclusively associated with isolated CCHS, whereas frameshift variants, although less frequent, are often more severe than polyAla expansions and identified in syndromic CCHS. This article provides a complete review of all the frameshift mutations identified in cases of isolated and syndromic CCHS reported in the literature as well as those identified by us and not yet published. These were considered in terms of both their structure, whether the underlying indels induced frameshifts of either 1 or 2 steps ("frame 2" and "frame 3" mutations respectively), and clinical associations. Furthermore, we evaluated the structural and functional effects of one "frame 3" mutation identified in a patient with isolated CCHS, and one "frame 2" mutation identified in a patient with syndromic CCHS, also affected with Hirschsprung's disease and neuroblastoma. The data thus obtained confirm that the type of translational frame affects the severity of the transcriptional dysfunction and the predisposition to isolated or syndromic CCHS.
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Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy.,CNR- Neuroscience Institute, Milan, Italy
| | | | - Silvia Cardani
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Annalisa Adamo
- UOC Genetica Medica, Istituto Giannina Gaslini, Genoa, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy.,CNR- Neuroscience Institute, Milan, Italy
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12
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Zhang YY, Gong JP, Li ZM. Autophagy and hepatic lipid metabolism. Shijie Huaren Xiaohua Zazhi 2017; 25:491-497. [DOI: 10.11569/wcjd.v25.i6.491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autophagy is initially thought to be a non-selective process in which intracellular proteins or damaged organelles are degraded. It is activated when cells lack nutrients and energy. Autophagy degrades cytoplasmic components within lysosomes and reuses the energy of amino acids to promote cell survival and maintain the cytoplasmic content. Current evidence implicates autophagy in the regulation of lipid stores within the two main organs involved in maintaining lipid homeostasis, the liver and adipose tissue. Upregulation of autophagy may lead to conversion of white adipose tissue into brown adipose tissue, thus regulating energy expenditure and obesity. Discovering new therapeutic interventions to treat lipid and lipoprotein disorders is of great interest and the discovery of autophagy as a regulator of lipid metabolism has opened up a new avenue for this area. In the liver, autophagy can play a role in some common metabolic disorders, which needs further research.
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13
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Congenital central hypoventilation syndrome: a bedside-to-bench success story for advancing early diagnosis and treatment and improved survival and quality of life. Pediatr Res 2017; 81:192-201. [PMID: 27673423 DOI: 10.1038/pr.2016.196] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/15/2016] [Indexed: 01/13/2023]
Abstract
The "bedside-to-bench" Congenital Central Hypoventilation Syndrome (CCHS) research journey has led to increased phenotypic-genotypic knowledge regarding autonomic nervous system (ANS) regulation, and improved clinical outcomes. CCHS is a neurocristopathy characterized by hypoventilation and ANS dysregulation. Initially described in 1970, timely diagnosis and treatment remained problematic until the first large cohort report (1992), delineating clinical presentation and treatment options. A central role of ANS dysregulation (2001) emerged, precipitating evaluation of genes critical to ANS development, and subsequent 2003 identification of Paired-Like Homeobox 2B (PHOX2B) as the disease-defining gene for CCHS. This breakthrough engendered clinical genetic testing, making diagnosis exact and early tracheostomy/artificial ventilation feasible. PHOX2B genotype-CCHS phenotype relationships were elucidated, informing early recognition and timely treatment for phenotypic manifestations including Hirschsprung disease, prolonged sinus pauses, and neural crest tumors. Simultaneously, cellular models of CCHS-causing PHOX2B mutations were developed to delineate molecular mechanisms. In addition to new insights regarding genetics and neurobiology of autonomic control overall, new knowledge gained has enabled physicians to anticipate and delineate the full clinical CCHS phenotype and initiate timely effective management. In summary, from an initial guarantee of early mortality or severe neurologic morbidity in survivors, CCHS children can now be diagnosed early and managed effectively, achieving dramatically improved quality of life as adults.
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Di Lascio S, Belperio D, Benfante R, Fornasari D. Alanine Expansions Associated with Congenital Central Hypoventilation Syndrome Impair PHOX2B Homeodomain-mediated Dimerization and Nuclear Import. J Biol Chem 2016; 291:13375-93. [PMID: 27129232 PMCID: PMC4933246 DOI: 10.1074/jbc.m115.679027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Indexed: 11/30/2022] Open
Abstract
Heterozygous mutations of the human PHOX2B gene, a key regulator of autonomic nervous system development, lead to congenital central hypoventilation syndrome (CCHS), a neurodevelopmental disorder characterized by a failure in the autonomic control of breathing. Polyalanine expansions in the 20-residues region of the C terminus of PHOX2B are the major mutations responsible for CCHS. Elongation of the alanine stretch in PHOX2B leads to a protein with altered DNA binding, transcriptional activity, and nuclear localization and the possible formation of cytoplasmic aggregates; furthermore, the findings of various studies support the idea that CCHS is not due to a pure loss of function mechanism but also involves a dominant negative effect and/or toxic gain of function for PHOX2B mutations. Because PHOX2B forms homodimers and heterodimers with its paralogue PHOX2A in vitro, we tested the hypothesis that the dominant negative effects of the mutated proteins are due to non-functional interactions with the wild-type protein or PHOX2A using a co-immunoprecipitation assay and the mammalian two-hybrid system. Our findings show that PHOX2B forms homodimers and heterodimerizes weakly with mutated proteins, exclude the direct involvement of the polyalanine tract in dimer formation, and indicate that mutated proteins retain partial ability to form heterodimers with PHOX2A. Moreover, in this study, we investigated the effects of the longest polyalanine expansions on the homeodomain-mediated nuclear import, and our data clearly show that the expanded C terminus interferes with this process. These results provide novel insights into the effects of the alanine tract expansion on PHOX2B folding and activity.
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Affiliation(s)
- Simona Di Lascio
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and
| | - Debora Belperio
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and
| | - Roberta Benfante
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and the National Research Council (CNR) Neuroscience Institute, 20129 Milan, Italy
| | - Diego Fornasari
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and the National Research Council (CNR) Neuroscience Institute, 20129 Milan, Italy
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15
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Healy F, Marcus CL. Care of the Child with Congenital Central Hypoventilation Syndrome. Respir Med 2016. [DOI: 10.1007/978-1-4939-3749-3_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Di Zanni E, Fornasari D, Ravazzolo R, Ceccherini I, Bachetti T. Identification of novel pathways and molecules able to down-regulate PHOX2B gene expression by in vitro drug screening approaches in neuroblastoma cells. Exp Cell Res 2015; 336:43-57. [PMID: 25882494 DOI: 10.1016/j.yexcr.2015.03.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/25/2015] [Accepted: 03/28/2015] [Indexed: 10/23/2022]
Abstract
PHOX2B is a transcription factor involved in the regulation of neurogenesis and in the correct differentiation of the autonomic nervous system. The pathogenetic role of PHOX2B in neuroblastoma (NB) is supported by mutations in familial, sporadic and syndromic cases of NB and overexpression of PHOX2B and its target ALK in tumor samples and NB cell lines. Starting from these observations, we have performed in vitro drug screening approaches targeting PHOX2B overexpression as a potential pharmacological means in NB. In particular, in order to identify molecules able to decrease PHOX2B expression, we have evaluated the effects of 70 compounds in IMR-32 cell line stably expressing the luciferase gene under the control of the PHOX2B promoter. Curcumin, SAHA and trichostatin A showed to down-regulate the PHOX2B promoter activity which resulted in a decrease of both protein and mRNA expressions. In addition, we have observed that curcumin acts by interfering with PBX-1/MEIS-1, NF-κB and AP-1 complexes, in this work demonstrated for the first time to regulate the transcription of the PHOX2B gene. Finally, combined drug treatments showed successful effects in down-regulating the expression of both PHOX2B and its target ALK genes, thus supporting the notion of the effectiveness of molecule combination in tumor therapy.
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Affiliation(s)
| | - Diego Fornasari
- Dipartimento di Farmacologia, Università degli Studi di Milano e CNR-Istituto di Neuroscienze, Italy
| | - Roberto Ravazzolo
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Italy; Università degli Studi di Genova, Italy
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The therapeutic effects of 4-phenylbutyric acid in maintaining proteostasis. Int J Biochem Cell Biol 2015; 61:45-52. [PMID: 25660369 DOI: 10.1016/j.biocel.2015.01.015] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 12/11/2022]
Abstract
Recently, there has been an increasing amount of literature published on the effects of 4-phenylbutyric acid (4-PBA) in various biological systems. 4-PBA is currently used clinically to treat urea cycle disorders under the trade name Buphenyl. Recent studies however have explored 4-PBA in the context of a low weight molecular weight chemical chaperone. Its properties as a chemical chaperone prevent misfolded protein aggregation and alleviate endoplasmic reticulum (ER) stress. As the ER is responsible for folding proteins targeted for use in membranes or secreted out of the cell, failure of maintaining adequate ER homeostasis may lead to protein misfolding and subsequent cell and organ pathology. Accumulation of misfolded proteins within the ER activates the unfolded protein response (UPR), a molecular repair response. The activation of the UPR aims to restore ER and cellular proteostasis by regulating the rate of synthesis of newly formed proteins as well as initiating molecular programs aimed to help fold or degrade misfolded proteins. If proteostasis is not restored, the UPR may initiate pro-apoptotic pathways. It is suggested that 4-PBA may help fold proteins in the ER, attenuating the activation of the UPR, and thus potentially alleviating various pathologies. This review discusses the biomedical research exploring the potential therapeutic effects of 4-PBA in various in vitro and in vivo model systems and clinical trials, while also commenting on the possible mechanisms of action.
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Trang H, Brunet JF, Rohrer H, Gallego J, Amiel J, Bachetti T, Fischbeck KH, Similowski T, Straus C, Ceccherini I, Weese-Mayer DE, Frerick M, Bieganowska K, Middleton L, Morandi F, Ottonello G. Proceedings of the fourth international conference on central hypoventilation. Orphanet J Rare Dis 2014; 9:194. [PMID: 25928806 PMCID: PMC4268904 DOI: 10.1186/s13023-014-0194-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/14/2014] [Indexed: 02/07/2023] Open
Abstract
Central hypoventilation syndromes (CHS) are rare diseases of central autonomic respiratory control associated with autonomous nervous dysfunction. Severe central hypoventilation is the hallmark and the most life-threatening feature. CHS is a group of not-fully defined disorders. Congenital CHS (CCHS) (ORPHA661) is clinically and genetically well-characterized, with the disease-causing gene identified in 2003. CCHS presents at birth in most cases, and associated with Hirschsprung's disease (ORPHA99803) and neural crest tumours in 20% and 5% of cases, respectively. The incidence of CCHS is estimated to be 1 of 200,000 live births in France, yet remains unknown for the rest of the world. In contrast, late-onset CHS includes a group of not yet fully delineated diseases. Overlap with CCHS is likely, as a subset of patients harbours PHOX2B mutations. Another subset of patients present with associated hypothalamic dysfunction. The number of these patients is unknown (less than 60 cases reported worldwide). Treatment of CHS is palliative using advanced techniques of ventilation support during lifetime. Research is ongoing to better understand physiopathological mechanisms and identify potential treatment pathways.The Fourth International Conference on Central Hypoventilation was organised in Warsaw, Poland, April 13-15, 2012, under the patronage of the European Agency for Health and Consumers and Public Health European Agency of European Community. The conference provided a state-of-the-art update of knowledge on all the genetic, molecular, cellular, and clinical aspects of these rare diseases.
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Affiliation(s)
- Ha Trang
- French Centre of Reference for Central Hypoventilation, Robert Debré University Hospital, EA 7334 REMES Paris-Diderot University, 48 boulevard Serurier, 75019, Paris, France.
| | | | - Hermann Rohrer
- Research Group Developmental Neurobiology, Department of Neurochemistry, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
| | - Jorge Gallego
- Inserm U676, Robert Debré University Hospital, Paris, France.
| | - Jeanne Amiel
- French Centre of Reference for Central Hypoventilation, Necker-Enfants Malades University Hospital, Paris, France.
| | | | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Missouri, USA.
| | - Thomas Similowski
- French Centre of Reference for Central Hypoventilation, La Pitié Salpêtrière University Hospital, Pierre et Maris Curie University, Paris, France.
| | - Christian Straus
- French Centre of Reference for Central Hypoventilation, La Pitié Salpêtrière University Hospital, Pierre et Maris Curie University, Paris, France.
| | - Isabella Ceccherini
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini, Genova, Italy.
| | - Debra E Weese-Mayer
- Autonomic Medicine in Paediatrics (CAMP), Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
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Tumor necrosis factor receptor-associated periodic syndrome as a model linking autophagy and inflammation in protein aggregation diseases. J Mol Med (Berl) 2014; 92:583-94. [PMID: 24706103 DOI: 10.1007/s00109-014-1150-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 03/21/2014] [Accepted: 03/27/2014] [Indexed: 01/09/2023]
Abstract
Autophagy prevents cellular damage by eliminating insoluble aggregates of mutant misfolded proteins, which accumulate under different pathological conditions. Downregulation of autophagy enhances the inflammatory response and thus represents a possible common pathogenic event underlying a number of autoinflammatory syndromes, such as tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS). The pathogenesis of other monogenic or complex disorders that display symptoms of excessive inflammation also involve the autophagy pathway. Studies have shown that TRAPS-associated TNFRSF1A mutations induce cytoplasmic retention of the TNFR1 receptor, defective TNF-induced apoptosis, and production of reactive oxygen species (ROS). Furthermore, autophagy impairment may account for the pathogenic effects of TNFRSF1A mutations, thus inducing inflammation in TRAPS. In this review, we summarize the molecular interactions and functional links between autophagy with regard to nuclear factor-kappa B activation, ROS production, and apoptosis. Furthermore, we propose a complex interplay of these pathways as a model to explain the relationship between mutant protein misfolding and inflammation in genetically determined and aggregation-prone diseases. Accordingly, autophagy function should be investigated in all diseases showing an inflammatory component, and for which the molecular pathogenesis is still unclear.
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Autophagy in aging and neurodegenerative diseases: implications for pathogenesis and therapy. Neurobiol Aging 2013; 35:941-57. [PMID: 24360503 DOI: 10.1016/j.neurobiolaging.2013.11.019] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 11/17/2013] [Accepted: 11/19/2013] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases, such as Alzheimer's disease Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, share a common cellular and molecular pathogenetic mechanism involving aberrant misfolded protein or peptide aggregation and deposition. Autophagy represents a major route for degradation of aggregated cellular proteins and dysfunctional organelles. Emerging studies have demonstrated that up-regulation of autophagy can lead to decreased levels of these toxic aggregate-prone proteins, and is beneficial in the context of aging and various models of neurodegenerative diseases. Understanding the signaling pathways involved in the regulation of autophagy is crucial to the development of strategies for therapy. This review will discuss the cellular and molecular mechanisms of autophagy and its important role in the pathogenesis of aging and neurodegenerative diseases, and the ongoing drug discovery strategies for therapeutic modulation.
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21
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Banerjee A, Apponi LH, Pavlath GK, Corbett AH. PABPN1: molecular function and muscle disease. FEBS J 2013; 280:4230-50. [PMID: 23601051 DOI: 10.1111/febs.12294] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 12/17/2022]
Abstract
The polyadenosine RNA binding protein polyadenylate-binding nuclear protein 1 (PABPN1) plays key roles in post-transcriptional processing of RNA. Although PABPN1 is ubiquitously expressed and presumably contributes to control of gene expression in all tissues, mutation of the PABPN1 gene causes the disease oculopharyngeal muscular dystrophy (OPMD), in which a limited set of skeletal muscles are affected. A major goal in the field of OPMD research is to understand why mutation of a ubiquitously expressed gene leads to a muscle-specific disease. PABPN1 plays a well-documented role in controlling the poly(A) tail length of RNA transcripts but new functions are emerging through studies that exploit a variety of unbiased screens as well as model organisms. This review addresses (a) the molecular function of PABPN1 incorporating recent findings that reveal novel cellular functions for PABPN1 and (b) the approaches that are being used to understand the molecular defects that stem from expression of mutant PABPN1. The long-term goal in this field of research is to understand the key molecular functions of PABPN1 in muscle as well as the mechanisms that underlie the pathological consequences of mutant PABPN1. Armed with this information, researchers can seek to develop therapeutic approaches to enhance the quality of life for patients afflicted with OPMD.
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Affiliation(s)
- Ayan Banerjee
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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22
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Ramanantsoa N, Gallego J. Congenital central hypoventilation syndrome. Respir Physiol Neurobiol 2013; 189:272-9. [PMID: 23692929 DOI: 10.1016/j.resp.2013.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/03/2013] [Accepted: 05/14/2013] [Indexed: 10/26/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) is characterized by hypoventilation during sleep and impaired ventilatory responses to hypercapnia and hypoxemia. Most cases are sporadic and caused by de novo PHOX2B gene mutations, which are usually polyalanine repeat expansions. Physiological and neuroanatomical studies of genetically engineered mice and analyses of cellular responses to mutated Phox2b have shed light on the pathophysiological mechanisms of CCHS. Findings in Phox2b(27Ala/+) knock-in mice consisted of unstable breathing with apneas, absence of the ventilatory response to hypercapnia, death within a few hours after birth, and absence of the retrotrapezoid nucleus (RTN). Conditional mouse mutants in which Phox2b(27Ala) was targeted to the RTN also lacked the ventilatory response to hypercapnia at birth but survived to adulthood and developed a partial hypercapnia response. The therapeutic effects of desogestrel are being evaluated in clinical trials, and recent analyses of cellular responses to polyAla Phox2b aggregates have suggested new pharmacological approaches designed to counteract the toxic effects of mutated Phox2b.
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Affiliation(s)
- N Ramanantsoa
- INSERM, U676, Hôpital Robert Debré, 75019 Paris, France; Université Paris Diderot, Paris, France
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23
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Hughes JN, Thomas PQ. Molecular pathology of polyalanine expansion disorders: new perspectives from mouse models. Methods Mol Biol 2013; 1017:135-51. [PMID: 23719913 DOI: 10.1007/978-1-62703-438-8_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Disease-causing polyalanine (PA) expansion mutations have been identified in nine genes, eight of which encode transcription factors (TFs) with important roles in development. In vitro and cell overexpression studies have shown that expanded PA tracts result in protein misfolding and the formation of aggregates. This feature of PA proteins is reminiscent of the related polyglutamine (PQ) disease proteins, which have been shown to cause disease via a gain-of-function (GOF) mechanism. However, in sharp contrast to PQ disorders, the disease phenotypes associated with PA mutations are more consistent with a LOF and/or mild GOF mechanism, suggesting that their molecular pathology is inherently different to PQ disorders. Elucidating the cellular impact of PA mutations in vivo has been difficult to address as, unlike the late-onset polyglutamine disorders, all PA disorders associated with TF gene mutations are congenital. However, in recent years, significant advances have been made through the analysis of engineered (knock-in) and spontaneous PA mouse models. Here we review these recent findings and propose an updated model of the molecular and cellular mechanism of PA disorders that incorporates both LOF and GOF features.
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Affiliation(s)
- James N Hughes
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
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24
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Pallauf K, Rimbach G. Autophagy, polyphenols and healthy ageing. Ageing Res Rev 2013; 12:237-52. [PMID: 22504405 DOI: 10.1016/j.arr.2012.03.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/22/2012] [Accepted: 03/30/2012] [Indexed: 01/25/2023]
Abstract
Autophagy is a lysosomal degradation process that evolved as a starvation response in lower eukaryotes and has gained numerous functions in higher organisms. In animals, autophagy works as a central process in cellular quality control by removing waste or excess proteins and organelles. Impaired autophagy and the age-related decline of this pathway favour the pathogenesis of many diseases that occur especially at higher age such as neurodegenerative diseases and cancer. Caloric restriction (CR) promotes longevity and healthy ageing. Currently, the contributing role of autophagy in the context of CR-induced health benefits is being unravelled. Furthermore recent studies imply that the advantages from polyphenol consumption may be also connected to autophagy induction. In this review, the literature on autophagy regulation by (dietary) polyphenols such as resveratrol, catechin, quercetin, silibinin and curcumin is discussed with a focus on the underlying molecular mechanisms. Special attention is paid to the implications of age-related autophagy decline for diseases and the possibility of dietary countermeasures.
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25
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Di Lascio S, Bachetti T, Saba E, Ceccherini I, Benfante R, Fornasari D. Transcriptional dysregulation and impairment of PHOX2B auto-regulatory mechanism induced by polyalanine expansion mutations associated with congenital central hypoventilation syndrome. Neurobiol Dis 2012; 50:187-200. [PMID: 23103552 DOI: 10.1016/j.nbd.2012.10.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/09/2012] [Accepted: 10/20/2012] [Indexed: 11/26/2022] Open
Abstract
The PHOX2B transcription factor plays a crucial role in autonomic nervous system development. In humans, heterozygous mutations of the PHOX2B gene lead to congenital central hypoventilation syndrome (CCHS), a rare disorder characterized by a broad variety of symptoms of autonomic nervous system dysfunction including inadequate control of breathing. The vast majority of patients with CCHS are heterozygous for a polyalanine repeat expansion mutation involving a polyalanine tract of twenty residues in the C-terminus of PHOX2B. Although several lines of evidence support a dominant-negative mechanism for PHOX2B mutations in CCHS, the molecular effects of PHOX2B mutant proteins on the transcriptional activity of the wild-type protein have not yet been elucidated. As one of the targets of PHOX2B is the PHOX2B gene itself, we tested the transcriptional activity of wild-type and mutant proteins on the PHOX2B gene promoter, and found that the transactivation ability of proteins with polyalanine expansions decreased as a function of the length of the expansion, whereas DNA binding was severely affected only in the case of the mutant with the longest polyalanine tract (+13 alanine). Co-transfection experiments using equimolar amounts of PHOX2B wild-type and mutant proteins in order to simulate a heterozygous state in vitro and four different PHOX2B target gene regulatory regions (PHOX2B, PHOX2A, DBH, TLX2) clearly showed that the polyalanine expanded proteins alter the transcriptional activity of wild-type protein in a promoter-specific manner, without any clear correlation with the length of the expansion. Moreover, although reduced transactivation may be caused by retention of the wild-type protein in the cytoplasm or in nuclear aggregates, this mechanism can only be partially responsible for the pathogenesis of CCHS because of the reduction in cytoplasmic and nuclear accumulation when the +13 alanine mutant is co-expressed with wild-type protein, and the fact that the shortest polyalanine expansions do not form visible cytoplasmic aggregates. Deletion of the C-terminal of PHOX2B leads to a protein that correctly localizes in the nucleus but impairs PHOX2B wild-type transcriptional activity, thus suggesting that protein mislocalization is not the only mechanism leading to CCHS. The results of this study provide novel in vitro experimental evidence of a transcriptional dominant-negative effect of PHOX2B polyalanine mutant proteins on wild-type protein on two different PHOX2B target genes.
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Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
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26
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Janda E, Isidoro C, Carresi C, Mollace V. Defective autophagy in Parkinson's disease: role of oxidative stress. Mol Neurobiol 2012; 46:639-61. [PMID: 22899187 DOI: 10.1007/s12035-012-8318-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/30/2012] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is a paradigmatic example of neurodegenerative disorder with a critical role of oxidative stress in its etiopathogenesis. Genetic susceptibility factors of PD, such as mutations in Parkin, PTEN-induced kinase 1, and DJ-1 as well as the exposure to pesticides and heavy metals, both contribute to altered redox balance and degeneration of dopaminergic neurons in the substantia nigra. Dysregulation of autophagy, a lysosomal-driven process of self degradation of cellular organelles and protein aggregates, is also implicated in PD and PD-related mutations, and environmental toxins deregulate autophagy. However, experimental evidence suggests a complex and ambiguous role of autophagy in PD since either impaired or abnormally upregulated autophagic flux has been shown to cause neuronal loss. Finally, it is generally believed that oxidative stress is a strong proautophagic stimulus. However, some evidence coming from neurobiology as well as from other fields indicate an inhibitory role of reactive oxygen species and reactive nitrogen species on the autophagic machinery. This review examines the scientific evidence supporting different concepts on how autophagy is dysregulated in PD and attempts to reconcile apparently contradictory views on the role of oxidative stress in autophagy regulation. The complex relationship between autophagy and oxidative stress is also considered in the context of the ongoing search for a novel PD therapy.
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Affiliation(s)
- Elzbieta Janda
- Department of Health Sciences, University Magna Graecia, Edificio Bioscienze, viale Europa, Campus Salvatore Venuta, Germaneto, 88100 Catanzaro, Italy.
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The E3 ubiquitin ligase TRIM11 mediates the degradation of congenital central hypoventilation syndrome-associated polyalanine-expanded PHOX2B. J Mol Med (Berl) 2012; 90:1025-35. [PMID: 22307522 DOI: 10.1007/s00109-012-0868-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 12/15/2011] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
Abstract
Expansions of a polyalanine (polyA) stretch in the coding region of the PHOX2B gene cause congenital central hypoventilation syndrome (CCHS), a neurocristopathy characterized by the absence of adequate control of autonomic breathing. Expansion of polyA in PHOX2B leads to protein misfolding and accumulation into inclusions. The mechanisms that regulate mutant protein degradation and turnover have been poorly elucidated. Here, we investigate the regulation of degradation of wild-type and polyA-expanded PHOX2B. We show that expanded PHOX2B is targeted for degradation through the ubiquitin-proteasome system, resulting in lowered levels of the mutant protein relative to its wild-type counterpart. Moreover, we show that mutant PHOX2B forms ubiquitin-positive inclusions, which sequester wild-type PHOX2B. This sequestration correlates with reduced transcriptional activity of endogenous wild-type protein in neuroblastoma cells. Finally, we show that the E3 ubiquitin ligase TRIM11 plays a critical role in the clearance of mutant PHOX2B through the proteasome. Importantly, clearance of mutant PHOX2B by TRIM11 correlates with a rescue of PHOX2B transcriptional activity. We propose that CCHS is partially caused by a dominant-negative effect of expanded PHOX2B due to the retention of the wild-type protein in pathogenic aggregates. Our results demonstrate that TRIM11 is a novel modifier of mutant PHOX2B toxicity and represents a potential therapeutic target for CCHS.
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