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Konishi CT, Moulayes N, Butola T, Zhang V, Kagan D, Yang Q, Pressler M, Dirvin BG, Devinsky O, Basu J, Long C. Modeling and Correction of Protein Conformational Disease in iPSC-derived Neurons through Personalized Base Editing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.576134. [PMID: 38293034 PMCID: PMC10827171 DOI: 10.1101/2024.01.17.576134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Altered protein conformation can cause incurable neurodegenerative disorders. Mutations in SERPINI1 , the gene encoding neuroserpin, alter protein conformation resulting in cytotoxic aggregation in neuronal endoplasmic reticulum. Aggregates cause oxidative stress impairing function, leading to neuronal death. Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a rare autosomal dominant progressive myoclonic epilepsy. Patients present with seizures and cognitive impairments that progress to dementia and premature death. We developed HEK293T and induced pluripotent stem cell (iPSC) models of FENIB, harboring the patient's pathogenic SERPINI1 variant or stably overexpressing mutant neuroserpin fused to GFP (MUT NS-GFP). FENIB cells form neuroserpin inclusions which increase in size and number. Here, we utilized a personalized adenine base editor (ABE)-mediated approach to efficiently correct the pathogenic variant and to restore neuronal dendritic morphology. ABE-treated MUT NS-GFP cells demonstrated reduced inclusion size and number. Using an inducible MUT NS-GFP neuron system, we identified early prevention of toxic protein expression allowed aggregate clearance, while late prevention halted neuronal impairments. To address several challenges for clinical applications of gene correction, we developed a neuron-specific engineered virus-like particle to optimize neuronal ABE delivery. Preventing mutant protein with altered conformation production improved toxic protein clearance. Our findings provide a targeted strategy and may treat FENIB and potentially other neurodegenerative diseases due to altered protein conformation such as Alzheimer's and Huntington's diseases.
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Fung C, Wilding B, Schittenhelm RB, Bryson-Richardson RJ, Bird PI. Expression of the Z Variant of α1-Antitrypsin Suppresses Hepatic Cholesterol Biosynthesis in Transgenic Zebrafish. Int J Mol Sci 2023; 24:ijms24032475. [PMID: 36768797 PMCID: PMC9917206 DOI: 10.3390/ijms24032475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/31/2023] Open
Abstract
Individuals homozygous for the Pi*Z allele of SERPINA1 (ZAAT) are susceptible to lung disease due to insufficient α1-antitrypsin secretion into the circulation and may develop liver disease due to compromised protein folding that leads to inclusion body formation in the endoplasmic reticulum (ER) of hepatocytes. Transgenic zebrafish expressing human ZAAT show no signs of hepatic accumulation despite displaying serum insufficiency, suggesting the defect in ZAAT secretion occurs independently of its tendency to form inclusion bodies. In this study, proteomic, transcriptomic, and biochemical analysis provided evidence of suppressed Srebp2-mediated cholesterol biosynthesis in the liver of ZAAT-expressing zebrafish. To investigate the basis for this perturbation, CRISPR/Cas9 gene editing was used to manipulate ER protein quality control factors. Mutation of erlec1 resulted in a further suppression in the cholesterol biosynthesis pathway, confirming a role for this ER lectin in targeting misfolded ZAAT for ER-associated degradation (ERAD). Mutation of the two ER mannosidase homologs enhanced ZAAT secretion without inducing hepatic accumulation. These insights into hepatic ZAAT processing suggest potential therapeutic targets to improve secretion and alleviate serum insufficiency in this form of the α1-antitrypsin disease.
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Affiliation(s)
- Connie Fung
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Correspondence: (C.F.); (P.I.B.)
| | - Brendan Wilding
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
| | - Ralf B. Schittenhelm
- Monash Proteomics and Metabolomics Facility, Monash University, Melbourne 3800, Australia
| | | | - Phillip I. Bird
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Correspondence: (C.F.); (P.I.B.)
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D'Acunto E, Gianfrancesco L, Serangeli I, D'Orsi M, Sabato V, Guadagno NA, Bhosale G, Caristi S, Failla AV, De Jaco A, Cacci E, Duchen MR, Lupo G, Galliciotti G, Miranda E. Polymerogenic neuroserpin causes mitochondrial alterations and activates NFκB but not the UPR in a neuronal model of neurodegeneration FENIB. Cell Mol Life Sci 2022; 79:437. [PMID: 35864382 PMCID: PMC9304071 DOI: 10.1007/s00018-022-04463-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/10/2022] [Accepted: 07/02/2022] [Indexed: 12/02/2022]
Abstract
The neurodegenerative condition FENIB (familiar encephalopathy with neuroserpin inclusion bodies) is caused by heterozygous expression of polymerogenic mutant neuroserpin (NS), with polymer deposition within the endoplasmic reticulum (ER) of neurons. We generated transgenic neural progenitor cells (NPCs) from mouse fetal cerebral cortex stably expressing either the control protein GFP or human wild type, polymerogenic G392E or truncated (delta) NS. This cellular model makes it possible to study the toxicity of polymerogenic NS in the appropriated cell type by in vitro differentiation to neurons. Our previous work showed that expression of G392E NS in differentiated NPCs induced an adaptive response through the upregulation of several genes involved in the defence against oxidative stress, and that pharmacological reduction of the antioxidant defences by drug treatments rendered G392E NS neurons more susceptible to apoptosis than control neurons. In this study, we assessed mitochondrial distribution and found a higher percentage of perinuclear localisation in G392E NS neurons, particularly in those containing polymers, a phenotype that was enhanced by glutathione chelation and rescued by antioxidant molecules. Mitochondrial membrane potential and contact sites between mitochondria and the ER were reduced in neurons expressing the G392E mutation. These alterations were associated with a pattern of ER stress that involved the ER overload response but not the unfolded protein response. Our results suggest that intracellular accumulation of NS polymers affects the interaction between the ER and mitochondria, causing mitochondrial alterations that contribute to the neuronal degeneration seen in FENIB patients.
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Affiliation(s)
- E D'Acunto
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - L Gianfrancesco
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - I Serangeli
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - M D'Orsi
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - V Sabato
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - N A Guadagno
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - G Bhosale
- Department of Cell and Developmental Biology, University College London, London, UK
| | - S Caristi
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - A V Failla
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - A De Jaco
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - E Cacci
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - M R Duchen
- Department of Cell and Developmental Biology, University College London, London, UK
| | - G Lupo
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - G Galliciotti
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - E Miranda
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy.
- Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy.
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4
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Disruption of the Ubiquitin-Proteasome System and Elevated Endoplasmic Reticulum Stress in Epilepsy. Biomedicines 2022; 10:biomedicines10030647. [PMID: 35327449 PMCID: PMC8945847 DOI: 10.3390/biomedicines10030647] [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: 02/15/2022] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 02/06/2023] Open
Abstract
The epilepsies are a broad group of conditions characterized by repeated seizures, and together are one of the most common neurological disorders. Additionally, epilepsy is comorbid with many neurological disorders, including lysosomal storage diseases, syndromic intellectual disability, and autism spectrum disorder. Despite the prevalence, treatments are still unsatisfactory: approximately 30% of epileptic patients do not adequately respond to existing therapeutics, which primarily target ion channels. Therefore, new therapeutic approaches are needed. Disturbed proteostasis is an emerging mechanism in epilepsy, with profound effects on neuronal health and function. Proteostasis, the dynamic balance of protein synthesis and degradation, can be directly disrupted by epilepsy-associated mutations in various components of the ubiquitin-proteasome system (UPS), or impairments can be secondary to seizure activity or misfolded proteins. Endoplasmic reticulum (ER) stress can arise from failed proteostasis and result in neuronal death. In light of this, several treatment modalities that modify components of proteostasis have shown promise in the management of neurological disorders. These include chemical chaperones to assist proper folding of proteins, inhibitors of overly active protein degradation, and enhancers of endogenous proteolytic pathways, such as the UPS. This review summarizes recent work on the pathomechanisms of abnormal protein folding and degradation in epilepsy, as well as treatment developments targeting this area.
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Godinez A, Rajput R, Chitranshi N, Gupta V, Basavarajappa D, Sharma S, You Y, Pushpitha K, Dhiman K, Mirzaei M, Graham S, Gupta V. Neuroserpin, a crucial regulator for axogenesis, synaptic modelling and cell-cell interactions in the pathophysiology of neurological disease. Cell Mol Life Sci 2022; 79:172. [PMID: 35244780 PMCID: PMC8897380 DOI: 10.1007/s00018-022-04185-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 01/31/2023]
Abstract
Neuroserpin is an axonally secreted serpin that is involved in regulating plasminogen and its enzyme activators, such as tissue plasminogen activator (tPA). The protein has been increasingly shown to play key roles in neuronal development, plasticity, maturation and synaptic refinement. The proteinase inhibitor may function both independently and through tPA-dependent mechanisms. Herein, we discuss the recent evidence regarding the role of neuroserpin in healthy and diseased conditions and highlight the participation of the serpin in various cellular signalling pathways. Several polymorphisms and mutations have also been identified in the protein that may affect the serpin conformation, leading to polymer formation and its intracellular accumulation. The current understanding of the involvement of neuroserpin in Alzheimer's disease, cancer, glaucoma, stroke, neuropsychiatric disorders and familial encephalopathy with neuroserpin inclusion bodies (FENIB) is presented. To truly understand the detrimental consequences of neuroserpin dysfunction and the effective therapeutic targeting of this molecule in pathological conditions, a cross-disciplinary understanding of neuroserpin alterations and its cellular signaling networks is essential.
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Affiliation(s)
- Angela Godinez
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Rashi Rajput
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Nitin Chitranshi
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
| | - Veer Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Devaraj Basavarajappa
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Samridhi Sharma
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Yuyi You
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Kanishka Pushpitha
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Kunal Dhiman
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Mehdi Mirzaei
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Stuart Graham
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
- Save Sight Institute, University of Sydney, Sydney, NSW, Australia
| | - Vivek Gupta
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
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6
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Neuroserpin Inclusion Bodies in a FENIB Yeast Model. Microorganisms 2021; 9:microorganisms9071498. [PMID: 34361933 PMCID: PMC8305157 DOI: 10.3390/microorganisms9071498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/01/2021] [Accepted: 07/09/2021] [Indexed: 11/17/2022] Open
Abstract
FENIB (familial encephalopathy with neuroserpin inclusion bodies) is a human monogenic disease caused by point mutations in the SERPINI1 gene, characterized by the intracellular deposition of polymers of neuroserpin (NS), which leads to proteotoxicity and cell death. Despite the different cell and animal models developed thus far, the exact mechanism of cell toxicity elicited by NS polymers remains unclear. Here, we report that human wild-type NS and the polymerogenic variant G392E NS form protein aggregates mainly localized within the endoplasmic reticulum (ER) when expressed in the yeast S. cerevisiae. The expression of NS in yeast delayed the exit from the lag phase, suggesting that NS inclusions cause cellular stress. The cells also showed a higher resistance following mild oxidative stress treatments when compared to control cells. Furthermore, the expression of NS in a pro-apoptotic mutant strain-induced cell death during aging. Overall, these data recapitulate phenotypes observed in mammalian cells, thereby validating S. cerevisiae as a model for FENIB.
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Han S, Fei F, Sun S, Zhang D, Dong Q, Wang X, Wang L. Increased anxiety was found in serpini1 knockout zebrafish larval. Biochem Biophys Res Commun 2021; 534:1013-1019. [PMID: 33168193 DOI: 10.1016/j.bbrc.2020.10.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022]
Abstract
Serpini1, which encodes neuroserpin, has been implicated in the development and normal function of the nervous system. Mutations in serpini1 cause familial encephalopathy, a rare neurodegenerative disorder characterized with neuroserpin inclusion bodies. However, function of neuroserpin in the nervous system is not fully understood. In this study, we generated a novel serpini1 mutant zebrafish model to investigate the loss of function of neuroserpin. Serpini1- deficient mutation was created with the CRISPR/Cas9 technique. No severe morphological characteristics were found in serpini1- deficient zebrafish. Serpini1-/- zebrafish larvae did not cause locomotor defects but displayed anxiety-like behavior. Extension of motoneurons axon defect was observed in serpini1-/- zebrafish. Furthermore, RNA-sequencing analysis revealed that loss of serpini1 resulted in affected expression of neurodegeneration-related genes.
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Affiliation(s)
- Sha Han
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Fei Fei
- Nanjing Drum Tower Hospital, 321 Zhongshan Road, Nanjing, 210008, People's Republic of China
| | - Shaoyang Sun
- Key Laboratory of Metabolism and Molecular Medicine, Ministry Education, Department of Biochemistry and Molecular Biology School of Basic Medical Sciences, Fudan University, Shanghai, 200032, People's Republic of China
| | - Dongyang Zhang
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Qiang Dong
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Xu Wang
- Cancer Metabolism Laboratory, Cancer Research Institute Fudan University Shanghai Cancer Center, Shanghai, 200032, People's Republic of China
| | - Liang Wang
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China.
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8
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Chambers JE, Dickens JA, Marciniak SJ. Measuring the effects of α 1 -antitrypsin polymerisation on the structure and biophysical properties of the endoplasmic reticulum. Biol Cell 2018; 110:249-255. [PMID: 30129166 DOI: 10.1111/boc.201800023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/29/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022]
Abstract
An important function of the endoplasmic reticulum (ER) is to serve as a site of secretory protein folding. When the accumulation of misfolded proteins threatens to disturb luminal homoeostasis, the cell is said to experience ER stress. By contrast, the accumulation of well-folded proteins inside the ER leads to a distinct form of strain called ER overload. The serpins comprise a large family of proteins whose folding has been studied in great detail. Some mutant serpins misfold to cause ER stress, whereas others fold but then polymerise to cause ER overload. We discuss recent advances in the use of dynamic fluorescence imaging to study these phenomena. We also discuss a new technique that we recently published, rotor-based organelle viscosity imaging (ROVI), which promises to shed more light on the biophysical features of ER stress and ER overload.
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Affiliation(s)
- Joseph E Chambers
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
| | - Jennifer A Dickens
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
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9
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Abstract
Alpha-1 antitrypsin deficiency is predominantly caused by point mutations that alter the protein's folding. These mutations fall into two broad categories: those that destabilize the protein dramatically and lead to its post-translational degradation and those that affect protein structure more subtly to promote protein polymerization within the endoplasmic reticulum (ER). This distinction is important because it determines the cell's response to each mutant. The severely misfolded mutants trigger an unfolded protein response (UPR) that promotes improved protein folding but can kill the cell in the chronic setting. In contrast, mutations that permit polymer formation fail to activate the UPR but instead promote a nuclear factor-κB-mediated ER overload response. The ability of polymers to increase a cell's sensitivity to ER stress likely explains apparent inconsistencies in the alpha-1 antitrypsin-signaling literature that have linked polymers with the UPR. In this review we discuss the use of mutant serpins to dissect each signaling pathway.
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Guadagno NA, Moriconi C, Licursi V, D'Acunto E, Nisi PS, Carucci N, De Jaco A, Cacci E, Negri R, Lupo G, Miranda E. Neuroserpin polymers cause oxidative stress in a neuronal model of the dementia FENIB. Neurobiol Dis 2017; 103:32-44. [PMID: 28363799 PMCID: PMC5439028 DOI: 10.1016/j.nbd.2017.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 03/10/2017] [Accepted: 03/26/2017] [Indexed: 01/20/2023] Open
Abstract
The serpinopathies are human pathologies caused by mutations that promote polymerisation and intracellular deposition of proteins of the serpin superfamily, leading to a poorly understood cell toxicity. The dementia FENIB is caused by polymerisation of the neuronal serpin neuroserpin (NS) within the endoplasmic reticulum (ER) of neurons. With the aim of understanding the toxicity due to intracellular accumulation of neuroserpin polymers, we have generated transgenic neural progenitor cell (NPC) cultures from mouse foetal cerebral cortex, stably expressing the control protein GFP (green fluorescent protein), or human wild type, G392E or delta NS. We have characterised these cell lines in the proliferative state and after differentiation to neurons. Our results show that G392E NS formed polymers that were mostly retained within the ER, while wild type NS was correctly secreted as a monomeric protein into the culture medium. Delta NS was absent at steady state due to its rapid degradation, but it was easily detected upon proteasomal block. Looking at their intracellular distribution, wild type NS was found in partial co-localisation with ER and Golgi markers, while G392E NS was localised within the ER only. Furthermore, polymers of NS were detected by ELISA and immunofluorescence in neurons expressing the mutant but not the wild type protein. We used control GFP and G392E NPCs differentiated to neurons to investigate which cellular pathways were modulated by intracellular polymers by performing RNA sequencing. We identified 747 genes with a significant upregulation (623) or downregulation (124) in G392E NS-expressing cells, and we focused our attention on several genes involved in the defence against oxidative stress that were up-regulated in cells expressing G392E NS (Aldh1b1, Apoe, Gpx1, Gstm1, Prdx6, Scara3, Sod2). Inhibition of intracellular anti-oxidants by specific pharmacological reagents uncovered the damaging effects of NS polymers. Our results support a role for oxidative stress in the cellular toxicity underlying the neurodegenerative dementia FENIB.
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Affiliation(s)
- Noemi A Guadagno
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Claudia Moriconi
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Valerio Licursi
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy; Institute for Systems Analysis and Computer Science 'Antonio Ruberti', National Research Council, Rome, Italy
| | - Emanuela D'Acunto
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Paola S Nisi
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Nicoletta Carucci
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Antonella De Jaco
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Emanuele Cacci
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Rodolfo Negri
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy; Institute of Biology and Molecular Pathology (IBPM), National Research Council, Rome, Italy
| | - Giuseppe Lupo
- Dpt. of Chemistry, Sapienza University of Rome, Italy.
| | - Elena Miranda
- Dpt. of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Italy.
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11
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Giampietro C, Lionetti MC, Costantini G, Mutti F, Zapperi S, La Porta CAM. Cholesterol impairment contributes to neuroserpin aggregation. Sci Rep 2017; 7:43669. [PMID: 28255164 PMCID: PMC5334643 DOI: 10.1038/srep43669] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/27/2017] [Indexed: 01/05/2023] Open
Abstract
Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer's and Parkinson's diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.
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Affiliation(s)
| | - Maria Chiara Lionetti
- Center for Complexity and Biosystems, Department of Biosciences, University of Milano, via Celoria 26, 20133 Milano, Italy
| | - Giulio Costantini
- Center for Complexity and Biosystems, Department of Physics, University of Milano, via Celoria 16, 20133 Milano, Italy
| | - Federico Mutti
- Center for Complexity and Biosystems, Department of Biosciences, University of Milano, via Celoria 26, 20133 Milano, Italy
| | - Stefano Zapperi
- Center for Complexity and Biosystems, Department of Physics, University of Milano, via Celoria 16, 20133 Milano, Italy
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica della Materia Condensata e di Tecnologie per l’Energia, Via R. Cozzi 53, 20125 Milano, Italy
- ISI Foundation, Via Alassio 11C, Torino, Italy
- Department of Applied Physics, Aalto University, P.O. Box 14100, FIN-00076, Aalto, Finland
| | - Caterina A. M. La Porta
- Center for Complexity and Biosystems, Department of Biosciences, University of Milano, via Celoria 26, 20133 Milano, Italy
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12
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Lee TW, Tsang VWK, Loef EJ, Birch NP. Physiological and pathological functions of neuroserpin: Regulation of cellular responses through multiple mechanisms. Semin Cell Dev Biol 2017; 62:152-159. [PMID: 27639894 DOI: 10.1016/j.semcdb.2016.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 11/17/2022]
Abstract
It is 27 years since neuroserpin was first discovered in the nervous system and identified as a member of the serpin superfamily. Since that time potential roles for this serine protease inhibitor have been identified in neuronal and non-neuronal systems. Many are linked to inhibition of neuroserpin's principal enzyme target, tissue plasminogen activator (tPA), although some have been suggested to involve alternate non-inhibitory mechanisms. This review focuses mainly on the inhibitory roles of neuroserpin and discusses the evidence supporting tPA as the physiological target. While the major sites of neuroserpin expression are neural, endocrine and immune tissues, most progress on characterizing functional roles for neuroserpin have been in the brain. Roles in emotional behaviour, synaptic plasticity and neuroprotection in stroke and excitotoxicity models are discussed. Current knowledge on three neurological diseases associated with neuroserpin mutation or activity, Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB), Alzheimer's disease and brain metastasis is presented. Finally, we consider mechanistic studies that have revealed a distinct inhibitory mechanism for neuroserpin and its possible implications for neuroserpin function.
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Affiliation(s)
- Tet Woo Lee
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand.
| | - Vicky W K Tsang
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Evert Jan Loef
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Nigel P Birch
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand; Brain Research New Zealand, Rangahau Roro Aotearoa, Auckland, New Zealand.
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13
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Dickens JA, Ordóñez A, Chambers JE, Beckett AJ, Patel V, Malzer E, Dominicus CS, Bradley J, Peden AA, Prior IA, Lomas DA, Marciniak SJ. The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-α1-antitrypsin. FASEB J 2016; 30:4083-4097. [PMID: 27601439 PMCID: PMC5102109 DOI: 10.1096/fj.201600430r] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022]
Abstract
α1-Antitrypsin is a serine protease inhibitor produced in the liver that is responsible for the regulation of pulmonary inflammation. The commonest pathogenic gene mutation yields Z-α1-antitrypsin, which has a propensity to self-associate forming polymers that become trapped in inclusions of endoplasmic reticulum (ER). It is unclear whether these inclusions are connected to the main ER network in Z-α1-antitrypsin-expressing cells. Using live cell imaging, we found that despite inclusions containing an immobile matrix of polymeric α1-antitrypsin, small ER resident proteins can diffuse freely within them. Inclusions have many features to suggest they represent fragmented ER, and some are physically separated from the tubular ER network, yet we observed cargo to be transported between them in a cytosol-dependent fashion that is sensitive to N-ethylmaleimide and dependent on Sar1 and sec22B. We conclude that protein recycling occurs between ER inclusions despite their physical separation.-Dickens, J. A., Ordóñez, A., Chambers, J. E., Beckett, A. J., Patel, V., Malzer, E., Dominicus, C. S., Bradley, J., Peden, A. A., Prior, I. A., Lomas, D. A., Marciniak, S. J. The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-α1-antitrypsin.
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Affiliation(s)
- Jennifer A Dickens
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Adriana Ordóñez
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Joseph E Chambers
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Alison J Beckett
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Vruti Patel
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Elke Malzer
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Caia S Dominicus
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Jayson Bradley
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Andrew A Peden
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Ian A Prior
- Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; and
| | - David A Lomas
- UCL Respiratory, University College London, London, United Kingdom
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research, Cambridge, United Kingdom;
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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14
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Moriconi C, Ordoñez A, Lupo G, Gooptu B, Irving JA, Noto R, Martorana V, Manno M, Timpano V, Guadagno NA, Dalton L, Marciniak SJ, Lomas DA, Miranda E. Interactions between N-linked glycosylation and polymerisation of neuroserpin within the endoplasmic reticulum. FEBS J 2015; 282:4565-79. [PMID: 26367528 PMCID: PMC4949553 DOI: 10.1111/febs.13517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 07/26/2015] [Accepted: 09/10/2015] [Indexed: 01/04/2023]
Abstract
The neuronal serpin neuroserpin undergoes polymerisation as a consequence of point mutations that alter its conformational stability, leading to a neurodegenerative dementia called familial encephalopathy with neuroserpin inclusion bodies (FENIB). Neuroserpin is a glycoprotein with predicted glycosylation sites at asparagines 157, 321 and 401. We used site-directed mutagenesis, transient transfection, western blot, metabolic labelling and ELISA to probe the relationship between glycosylation, folding, polymerisation and degradation of neuroserpin in validated cell models of health and disease. Our data show that glycosylation at N157 and N321 plays an important role in maintaining the monomeric state of neuroserpin, and we propose this is the result of steric hindrance or effects on local conformational dynamics that can contribute to polymerisation. Asparagine residue 401 is not glycosylated in wild type neuroserpin and in several polymerogenic variants that cause FENIB, but partial glycosylation was observed in the G392E mutant of neuroserpin that causes severe, early-onset dementia. Our findings indicate that N401 glycosylation reports lability of the C-terminal end of neuroserpin in its native state. This C-terminal lability is not required for neuroserpin polymerisation in the endoplasmic reticulum, but the additional glycan facilitates degradation of the mutant protein during proteasomal impairment. In summary, our results indicate how normal and variant-specific N-linked glycosylation events relate to intracellular folding, misfolding, degradation and polymerisation of neuroserpin.
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Affiliation(s)
- Claudia Moriconi
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Adriana Ordoñez
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, UK
| | - Giuseppe Lupo
- Department of Chemistry, Sapienza University of Rome, Italy
| | - Bibek Gooptu
- Division of Asthma, Allergy and Lung Biology, King's College London, UK
| | - James A Irving
- Wolfson Institute for Biomedical Research, University College London, UK
| | - Rosina Noto
- National Research Council of Italy, Institute of Biophysics, Palermo, Italy
| | - Vincenzo Martorana
- National Research Council of Italy, Institute of Biophysics, Palermo, Italy
| | - Mauro Manno
- National Research Council of Italy, Institute of Biophysics, Palermo, Italy
| | - Valentina Timpano
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Noemi A Guadagno
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Lucy Dalton
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, UK
| | - Stefan J Marciniak
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, UK
| | - David A Lomas
- Wolfson Institute for Biomedical Research, University College London, UK
| | - Elena Miranda
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
- Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Italy
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15
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Formoso K, García MD, Frasch AC, Scorticati C. Filopodia formation driven by membrane glycoprotein M6a depends on the interaction of its transmembrane domains. J Neurochem 2015; 134:499-512. [PMID: 25940868 DOI: 10.1111/jnc.13153] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 12/19/2022]
Abstract
Membrane glycoprotein M6a, which belongs to the tetraspan proteolipid protein family, promotes structural plasticity in neurons and cell lines by unknown mechanisms. This glycoprotein is encoded by Gpm6a, a stress-regulated gene. The hippocampus of animals chronically stressed by either psychosocial or physical stressors shows decreased M6a expression. Stressed Gpm6a-null mice develop a claustrophobia-like phenotype. In humans, de novo duplication of GPM6A results in learning/behavioral abnormalities, and two single-nucleotide polymorphisms (SNPs) in the non-coding region are linked to mood disorders. Here, we studied M6a dimerization in neuronal membranes and its functional relevance. We showed that the self-interaction of M6a transmembrane domains (TMDs) might be driving M6a dimerization, which is required to induce filopodia formation. Glycine mutants located in TMD2 and TMD4 of M6a affected its dimerization, thus preventing M6a-induced filopodia formation in neurons. In silico analysis of three non-synonymous SNPs located in the coding region of TMDs suggested that these mutations induce protein instability. Indeed, these SNPs prevented M6a from being functional in neurons, owing to decreased stability, dimerization or improper folding. Interestingly, SNP3 (W141R), which caused endoplasmic reticulum retention, is equivalent to that mutated in PLP1, W161L, which causes demyelinating Pelizaeus-Merzbacher disease. In this work we analyzed the functional contribution of transmembrane domains (TMDs) of the neuronal membrane glycoprotein M6a. We determined that certain glycines present in TMD2 and TMD4 are critical for filopodia induction in neurons. In addition, three nsSNPs located in the coding region of TMD2 and TMD3 of GPM6A impair M6a function by affecting its stability, folding and dimer formation.
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Affiliation(s)
- Karina Formoso
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
| | - Micaela D García
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
| | - Alberto C Frasch
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
| | - Camila Scorticati
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
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16
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Li F, Gao B, Dong H, Shi J, Fang D. Icariin induces synoviolin expression through NFE2L1 to protect neurons from ER stress-induced apoptosis. PLoS One 2015; 10:e0119955. [PMID: 25806530 PMCID: PMC4373914 DOI: 10.1371/journal.pone.0119955] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/26/2014] [Indexed: 11/19/2022] Open
Abstract
By suppressing neuronal apoptosis, Icariin is a potential therapeutic drug for neuronal degenerative diseases. The molecular mechanisms of Icariin anti-apoptotic functions are still largely unclear. In this report, we found that Icariin induces the expression of Synoviolin, an endoplasmic reticulum (ER)-anchoring E3 ubiquitin ligase that functions as a suppressor of ER stress-induced apoptosis. The nuclear factor erythroid 2-related factor 1 (NFE2L1) is responsible for Icariin-mediated Synoviolin gene expression. Mutation of the NFE2L1-binding sites in a distal region of the Synoviolin promoter abolished Icariin-induced Synoviolin promoter activity, and knockdown of NFE2L1 expression prevented Icariin-stimulated Synoviolin expression. More importantly, Icariin protected ER stress-induced apoptosis of PC12 cells in a Synoviolin-dependent manner. Therefore, our study reveals Icariin-induced Synoviolin expression through NFE2L1 as a previously unappreciated molecular mechanism underlying the neuronal protective function of Icariin.
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Affiliation(s)
- Fei Li
- Department of Pharmacology and the Key Laboratory of Basic Pharmacology of Guizhou Province, Zunyi Medical College, Zunyi, China
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Chicago, IL, 60611, United States of America
- * E-mail: (FL); (DF)
| | - Beixue Gao
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Chicago, IL, 60611, United States of America
| | - Hongxin Dong
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Chicago, IL, 60611, United States of America
| | - Jingshan Shi
- Department of Pharmacology and the Key Laboratory of Basic Pharmacology of Guizhou Province, Zunyi Medical College, Zunyi, China
| | - Deyu Fang
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Chicago, IL, 60611, United States of America
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17
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Noto R, Santangelo MG, Levantino M, Cupane A, Mangione MR, Parisi D, Ricagno S, Bolognesi M, Manno M, Martorana V. Functional and dysfunctional conformers of human neuroserpin characterized by optical spectroscopies and Molecular Dynamics. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1854:110-7. [PMID: 25450507 PMCID: PMC4332418 DOI: 10.1016/j.bbapap.2014.10.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/04/2014] [Accepted: 10/03/2014] [Indexed: 12/12/2022]
Abstract
Neuroserpin (NS) is a serine protease inhibitor (SERPIN) involved in different neurological pathologies, including the Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB), related to the aberrant polymerization of NS mutants. Here we present an in vitro and in silico characterization of native neuroserpin and its dysfunctional conformation isoforms: the proteolytically cleaved conformer, the inactive latent conformer, and the polymeric species. Based on circular dichroism and fluorescence spectroscopy, we present an experimental validation of the latent model and highlight the main structural features of the different conformers. In particular, emission spectra of aromatic residues yield distinct conformational fingerprints, that provide a novel and simple spectroscopic tool for selecting serpin conformers in vitro. Based on the structural relationship between cleaved and latent serpins, we propose a structural model for latent NS, for which an experimental crystallographic structure is lacking. Molecular Dynamics simulations suggest that NS conformational stability and flexibility arise from a spatial distribution of intramolecular salt-bridges and hydrogen bonds.
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Affiliation(s)
- Rosina Noto
- Institute of Biophysics, National Research Council of Italy, Palermo, Italy
| | | | - Matteo Levantino
- Department of Physics and Chemistry, University of Palermo, Palermo, Italy
| | - Antonio Cupane
- Department of Physics and Chemistry, University of Palermo, Palermo, Italy
| | | | - Daniele Parisi
- Institute of Biophysics, National Research Council of Italy, Palermo, Italy; Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy
| | - Stefano Ricagno
- Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy
| | - Martino Bolognesi
- Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy
| | - Mauro Manno
- Institute of Biophysics, National Research Council of Italy, Palermo, Italy.
| | - Vincenzo Martorana
- Institute of Biophysics, National Research Council of Italy, Palermo, Italy
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18
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Budrikis Z, Costantini G, La Porta CAM, Zapperi S. Protein accumulation in the endoplasmic reticulum as a non-equilibrium phase transition. Nat Commun 2014; 5:3620. [PMID: 24722051 PMCID: PMC4048836 DOI: 10.1038/ncomms4620] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 03/11/2014] [Indexed: 12/03/2022] Open
Abstract
Several neurological disorders are associated with the aggregation of aberrant proteins, often localized in intracellular organelles such as the endoplasmic reticulum. Here we study protein aggregation kinetics by mean-field reactions and three dimensional Monte carlo simulations of diffusion-limited aggregation of linear polymers in a confined space, representing the endoplasmic reticulum. By tuning the rates of protein production and degradation, we show that the system undergoes a non-equilibrium phase transition from a physiological phase with little or no polymer accumulation to a pathological phase characterized by persistent polymerization. A combination of external factors accumulating during the lifetime of a patient can thus slightly modify the phase transition control parameters, tipping the balance from a long symptomless lag phase to an accelerated pathological development. The model can be successfully used to interpret experimental data on amyloid-β clearance from the central nervous system. Misfolded protein accumulation is a hallmark of many neurodegenerative diseases. Here Budrikis et al. model protein aggregation in the endoplasmic reticulum and show that it is the result of a non-equilibrium phase transition caused by tipping the balance from the rates of protein production to degradation.
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Affiliation(s)
- Zoe Budrikis
- Institute for Scientific Interchange Foundation, Via Alassio 11/C, Torino 10126, Italy
| | - Giulio Costantini
- Istituto per l'Energetica e le Interfasi, CNR-Consiglio Nazionale delle Ricerche, Via R. Cozzi 53, Milano 20125, Italy
| | - Caterina A M La Porta
- Department of Biosciences, University of Milano, via Celoria 26, Milano 20133, Italy
| | - Stefano Zapperi
- 1] Institute for Scientific Interchange Foundation, Via Alassio 11/C, Torino 10126, Italy [2] Istituto per l'Energetica e le Interfasi, CNR-Consiglio Nazionale delle Ricerche, Via R. Cozzi 53, Milano 20125, Italy
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