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Sala-Gaston J, Pérez-Villegas EM, Armengol JA, Rawlins LE, Baple EL, Crosby AH, Ventura F, Rosa JL. Autophagy dysregulation via the USP20-ULK1 axis in the HERC2-related neurodevelopmental disorder. Cell Death Discov 2024; 10:163. [PMID: 38570483 PMCID: PMC10991529 DOI: 10.1038/s41420-024-01931-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024] Open
Abstract
Sequence variants in the HERC2 gene are associated with a significant reduction in HERC2 protein levels and cause a neurodevelopmental disorder known as the HERC2-related disorder, which shares clinical features with Angelman syndrome, including global developmental delay, intellectual disability, autism, and movement disorders. Remarkably, the HERC2 gene is commonly deleted in individuals with Angelman syndrome, suggesting a potential contribution of HERC2 to the pathophysiology of this disease. Given the known critical role of autophagy in brain development and its implication in neurodevelopmental diseases, we undertook different experimental approaches to monitor autophagy in fibroblasts derived from individuals affected by the HERC2-related disorder. Our findings reveal alterations in the levels of the autophagy-related protein LC3. Furthermore, experiments with lysosomal inhibitors provide confirmation of an upregulation of the autophagy pathway in these patient-derived cells. Mechanistically, we corroborate an interaction between HERC2 and the deubiquitylating enzyme USP20; and demonstrate that HERC2 deficiency leads to increased USP20 protein levels. Notably, USP20 upregulation correlates with enhanced stability of the autophagy initiating kinase ULK1, highlighting the role of HERC2 as an autophagy regulator factor through the USP20-ULK1 axis. Moreover, we show that p38 acts as a modulator of this pathway, since p38 activation disrupts HERC2-USP20 interaction, leading to increased USP20 and LC3-II protein levels. Together, these findings uncover a previously unknown role for HERC2 in autophagy regulation and provide insights into the pathomolecular mechanisms underlying the HERC2-related disorder and Angelman syndrome.
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Affiliation(s)
- Joan Sala-Gaston
- Department of Physiological Sciences, University of Barcelona (UB), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Eva M Pérez-Villegas
- Department of Physiology, Anatomy and Cell Biology, University Pablo de Olavide, 41013, Seville, Spain
| | - José A Armengol
- Department of Physiology, Anatomy and Cell Biology, University Pablo de Olavide, 41013, Seville, Spain
| | - Lettie E Rawlins
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, UK
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Emma L Baple
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, UK
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Andrew H Crosby
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Francesc Ventura
- Department of Physiological Sciences, University of Barcelona (UB), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Jose Luis Rosa
- Department of Physiological Sciences, University of Barcelona (UB), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Spain.
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Magnati S, Alladio E, Bracco E. A Survey on the Expression of the Ubiquitin Proteasome System Components HECT- and RBR-E3 Ubiquitin Ligases and E2 Ubiquitin-Conjugating and E1 Ubiquitin-Activating Enzymes during Human Brain Development. Int J Mol Sci 2024; 25:2361. [PMID: 38397039 PMCID: PMC10889685 DOI: 10.3390/ijms25042361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Human brain development involves a tightly regulated sequence of events that starts shortly after conception and continues up to adolescence. Before birth, neurogenesis occurs, implying an extensive differentiation process, sustained by changes in the gene expression profile alongside proteome remodeling, regulated by the ubiquitin proteasome system (UPS) and autophagy. The latter processes rely on the selective tagging with ubiquitin of the proteins that must be disposed of. E3 ubiquitin ligases accomplish the selective recognition of the target proteins. At the late stage of neurogenesis, the brain starts to take shape, and neurons migrate to their designated locations. After birth, neuronal myelination occurs, and, in parallel, neurons form connections among each other throughout the synaptogenesis process. Due to the malfunctioning of UPS components, aberrant brain development at the very early stages leads to neurodevelopmental disorders. Through deep data mining and analysis and by taking advantage of machine learning-based models, we mapped the transcriptomic profile of the genes encoding HECT- and ring-between-ring (RBR)-E3 ubiquitin ligases as well as E2 ubiquitin-conjugating and E1 ubiquitin-activating enzymes during human brain development, from early post-conception to adulthood. The inquiry outcomes unveiled some implications for neurodevelopment-related disorders.
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Affiliation(s)
- Stefano Magnati
- Centro Regionale Anti Doping—A. Bertinaria, Orbassano, 10043 Turin, Italy;
- Politecnico di Torino, 10129, Turin, Italy
| | - Eugenio Alladio
- Centro Regionale Anti Doping—A. Bertinaria, Orbassano, 10043 Turin, Italy;
- Department of Chemistry, University of Turin, 10125 Turin, Italy
| | - Enrico Bracco
- Department of Oncology, University of Turin, 10043 Orbassano, Italy
- Istituto Nazionale Ricerca Metrologica, 10135 Turin, Italy
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Yang S, Ting CY, Lilly MA. The GATOR2 complex maintains lysosomal-autophagic function by inhibiting the protein degradation of MiT/TFEs. Mol Cell 2024; 84:727-743.e8. [PMID: 38325378 PMCID: PMC10940221 DOI: 10.1016/j.molcel.2024.01.012] [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: 01/12/2023] [Revised: 07/31/2023] [Accepted: 01/17/2024] [Indexed: 02/09/2024]
Abstract
Lysosomes are central to metabolic homeostasis. The microphthalmia bHLH-LZ transcription factors (MiT/TFEs) family members MITF, TFEB, and TFE3 promote the transcription of lysosomal and autophagic genes and are often deregulated in cancer. Here, we show that the GATOR2 complex, an activator of the metabolic regulator TORC1, maintains lysosomal function by protecting MiT/TFEs from proteasomal degradation independent of TORC1, GATOR1, and the RAG GTPase. We determine that in GATOR2 knockout HeLa cells, members of the MiT/TFEs family are ubiquitylated by a trio of E3 ligases and are degraded, resulting in lysosome dysfunction. Additionally, we demonstrate that GATOR2 protects MiT/TFE proteins in pancreatic ductal adenocarcinoma and Xp11 translocation renal cell carcinoma, two cancers that are driven by MiT/TFE hyperactivation. In summary, we find that the GATOR2 complex has independent roles in TORC1 regulation and MiT/TFE protein protection and thus is central to coordinating cellular metabolism with control of the lysosomal-autophagic system.
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Affiliation(s)
- Shu Yang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chun-Yuan Ting
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mary A Lilly
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Wang W, Wang T, Gao Y, Liang G, Pu Y, Zhang J. Model of neural development by differentiating human induced pluripotent stem cells into neural progenitor cells to study the neurodevelopmental toxicity of lead. Food Chem Toxicol 2023; 179:113947. [PMID: 37467947 DOI: 10.1016/j.fct.2023.113947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 07/04/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Lead (Pb) exposure causes immeasurable damage to multiple human systems, particularly the central nervous system (CNS). In this study, human induced pluripotent stem cells (hiPSCs) were differentiated into neural progenitor cells (NPCs) to investigate the neurotoxic effects of Pb. The hiPSCs were treated with 0, 0.5, 1.0, 2.5, 5.0 and 10.0 μmol/L Pb for 7 days, whereas embryoid bodies (EBs) and NPCs were treated with 0, 0.1, 0.5, and 1.0 μmol/L Pb for 7 days. Pb exposure disrupted the cell cycle and caused apoptosis in hiPSCs, EBs, and NPCs. Besides, Pb inhibited the differentiation of NPCs and EBs. Whole exome sequencing revealed 2509, 2413, and 1984 single nucleotide variants (SNVs) caused by Pb in hiPSCs, EBs, and NPCs, respectively. The common mutation sites in the exon region were mostly nonsynonymous mutations. We identified 18, 19, and 18 common deleterious mutations in hiPSCs, EBs, and NPCs, respectively. Additionally, Online Mendelian Inheritance in Man database analysis revealed 30, 20, and 13 genes related to CNS disorders in hiPSCs, EBs, and NPCs, respectively. Our findings suggest that this in vitro model may supplement animal models and be applied to the study of neurodevelopmental toxicity in the future.
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Affiliation(s)
- Wei Wang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China
| | - Tong Wang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China
| | - Yu Gao
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China
| | - Juan Zhang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing, 210009, China; Jiangsu Institute for Sports and Health (JISH), Nanjing, 211100, China.
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Sala-Gaston J, Costa-Sastre L, Pedrazza L, Martinez-Martinez A, Ventura F, Rosa JL. Regulation of MAPK Signaling Pathways by the Large HERC Ubiquitin Ligases. Int J Mol Sci 2023; 24:ijms24054906. [PMID: 36902336 PMCID: PMC10003351 DOI: 10.3390/ijms24054906] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
Protein ubiquitylation acts as a complex cell signaling mechanism since the formation of different mono- and polyubiquitin chains determines the substrate's fate in the cell. E3 ligases define the specificity of this reaction by catalyzing the attachment of ubiquitin to the substrate protein. Thus, they represent an important regulatory component of this process. Large HERC ubiquitin ligases belong to the HECT E3 protein family and comprise HERC1 and HERC2 proteins. The physiological relevance of the Large HERCs is illustrated by their involvement in different pathologies, with a notable implication in cancer and neurological diseases. Understanding how cell signaling is altered in these different pathologies is important for uncovering novel therapeutic targets. To this end, this review summarizes the recent advances in how the Large HERCs regulate the MAPK signaling pathways. In addition, we emphasize the potential therapeutic strategies that could be followed to ameliorate the alterations in MAPK signaling caused by Large HERC deficiencies, focusing on the use of specific inhibitors and proteolysis-targeting chimeras.
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HERC2 promotes inflammation-driven cancer stemness and immune evasion in hepatocellular carcinoma by activating STAT3 pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2023; 42:38. [PMID: 36721234 PMCID: PMC9890722 DOI: 10.1186/s13046-023-02609-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/19/2023] [Indexed: 02/02/2023]
Abstract
BACKGROUND Hepatic inflammation is a common initiator of liver diseases and considered as the primary driver of hepatocellular carcinoma (HCC). However, the precise mechanism of inflammation-induced HCC development and immune evasion remains elusive and requires extensive investigation. This study sought to identify the new target that is involved in inflammation-related liver tumorigenesis. METHODS RNA-sequencing (RNA-seq) analysis was performed to identify the differential gene expression signature in primary human hepatocytes treated with or without inflammatory stimulus. A giant E3 ubiquitin protein ligase, HECT domain and RCC1-like domain 2 (HERC2), was identified in the analysis. Prognostic performance in the TCGA validation dataset was illustrated by Kaplan-Meier plot. The functional role of HERC2 in HCC progression was determined by knocking out and over-expressing HERC2 in various HCC cells. The precise molecular mechanism and signaling pathway networks associated with HERC2 in HCC stemness and immune evasion were determined by quantitative real-time PCR, immunofluorescence, western blot, and transcriptomic profiling analyses. To investigate the role of HERC2 in the etiology of HCC in vivo, we applied the chemical carcinogen diethylnitrosamine (DEN) to hepatocyte-specific HERC2-knockout mice. Additionally, the orthotopic transplantation mouse model of HCC was established to determine the effect of HERC2 during HCC development. RESULTS We found that increased HERC2 expression was correlated with poor prognosis in HCC patients. HERC2 enhanced the stemness and PD-L1-mediated immune evasion of HCC cells, which is associated with the activation of signal transducer and activator of transcription 3 (STAT3) pathway during the inflammation-cancer transition. Mechanically, HERC2 coupled with the endoplasmic reticulum (ER)-resident protein tyrosine phosphatase 1B (PTP1B) and limited PTP1B translocation from ER to ER-plasma membrane junction, which ameliorated the inhibitory role of PTP1B in Janus kinase 2 (JAK2) phosphorylation. Furthermore, HERC2 knockout in hepatocytes limited hepatic PD-L1 expression and ameliorated HCC progression in DEN-induced mouse liver carcinogenesis. In contrast, HERC2 overexpression promoted tumor development and progression in the orthotopic transplantation HCC model. CONCLUSION Our data identified HERC2 functions as a previously unknown modulator of the JAK2/STAT3 pathway, thereby promoting inflammation-induced stemness and immune evasion in HCC.
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Pedrazza L, Martinez-Martinez A, Sánchez-de-Diego C, Valer JA, Pimenta-Lopes C, Sala-Gaston J, Szpak M, Tyler-Smith C, Ventura F, Rosa JL. HERC1 deficiency causes osteopenia through transcriptional program dysregulation during bone remodeling. Cell Death Dis 2023; 14:17. [PMID: 36635269 PMCID: PMC9837143 DOI: 10.1038/s41419-023-05549-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 12/19/2022] [Accepted: 01/03/2023] [Indexed: 01/13/2023]
Abstract
Bone remodeling is a continuous process between bone-forming osteoblasts and bone-resorbing osteoclasts, with any imbalance resulting in metabolic bone disease, including osteopenia. The HERC1 gene encodes an E3 ubiquitin ligase that affects cellular processes by regulating the ubiquitination of target proteins, such as C-RAF. Of interest, an association exists between biallelic pathogenic sequence variants in the HERC1 gene and the neurodevelopmental disorder MDFPMR syndrome (macrocephaly, dysmorphic facies, and psychomotor retardation). Most pathogenic variants cause loss of HERC1 function, and the affected individuals present with features related to altered bone homeostasis. Herc1-knockout mice offer an excellent model in which to study the role of HERC1 in bone remodeling and to understand its role in disease. In this study, we show that HERC1 regulates osteoblastogenesis and osteoclastogenesis, proving that its depletion increases gene expression of osteoblastic makers during the osteogenic differentiation of mesenchymal stem cells. During this process, HERC1 deficiency increases the levels of C-RAF and of phosphorylated ERK and p38. The Herc1-knockout adult mice developed imbalanced bone homeostasis that presented as osteopenia in both sexes of the adult mice. By contrast, only young female knockout mice had osteopenia and increased number of osteoclasts, with the changes associated with reductions in testosterone and dihydrotestosterone levels. Finally, osteocytes isolated from knockout mice showed a higher expression of osteocytic genes and an increase in the Rankl/Opg ratio, indicating a relevant cell-autonomous role of HERC1 when regulating the transcriptional program of bone formation. Overall, these findings present HERC1 as a modulator of bone homeostasis and highlight potential therapeutic targets for individuals affected by pathological HERC1 variants.
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Affiliation(s)
- Leonardo Pedrazza
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Arturo Martinez-Martinez
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Cristina Sánchez-de-Diego
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - José Antonio Valer
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Carolina Pimenta-Lopes
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Joan Sala-Gaston
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Michal Szpak
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | | | - Francesc Ventura
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Jose Luis Rosa
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, L'Hospitalet de Llobregat, Spain.
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Sala-Gaston J, Pedrazza L, Ramirez J, Martinez-Martinez A, Rawlins LE, Baple EL, Crosby AH, Mayor U, Ventura F, Rosa JL. HERC2 deficiency activates C-RAF/MKK3/p38 signalling pathway altering the cellular response to oxidative stress. Cell Mol Life Sci 2022; 79:548. [PMID: 36241744 PMCID: PMC9568463 DOI: 10.1007/s00018-022-04586-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/03/2022]
Abstract
HERC2 gene encodes an E3 ubiquitin ligase involved in several cellular processes by regulating the ubiquitylation of different protein substrates. Biallelic pathogenic sequence variants in the HERC2 gene are associated with HERC2 Angelman-like syndrome. In pathogenic HERC2 variants, complete absence or marked reduction in HERC2 protein levels are observed. The most common pathological variant, c.1781C > T (p.Pro594Leu), encodes an unstable HERC2 protein. A better understanding of how pathologic HERC2 variants affect intracellular signalling may aid definition of potential new therapies for these disorders. For this purpose, we studied patient-derived cells with the HERC2 Pro594Leu variant. We observed alteration of mitogen-activated protein kinase signalling pathways, reflected by increased levels of C-RAF protein and p38 phosphorylation. HERC2 knockdown experiments reproduced the same effects in other human and mouse cells. Moreover, we demonstrated that HERC2 and RAF proteins form molecular complexes, pull-down and proteomic experiments showed that HERC2 regulates C-RAF ubiquitylation and we found out that the p38 activation due to HERC2 depletion occurs in a RAF/MKK3-dependent manner. The displayed cellular response was that patient-derived and other human cells with HERC2 deficiency showed higher resistance to oxidative stress with an increase in the master regulator of the antioxidant response NRF2 and its target genes. This resistance was independent of p53 and abolished by RAF or p38 inhibitors. Altogether, these findings identify the activation of C-RAF/MKK3/p38 signalling pathway in HERC2 Angelman-like syndrome and highlight the inhibition of RAF activity as a potential therapeutic option for individuals affected with these rare diseases.
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Affiliation(s)
- Joan Sala-Gaston
- Department of Physiological Sciences, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona (UB), C/ Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Spain
| | - Leonardo Pedrazza
- Department of Physiological Sciences, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona (UB), C/ Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Spain
| | - Juanma Ramirez
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, UPV/EHU, Leioa, Bizkaia, Spain
| | - Arturo Martinez-Martinez
- Department of Physiological Sciences, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona (UB), C/ Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Spain
| | - Lettie E Rawlins
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, UK.,Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Emma L Baple
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, UK.,Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Andrew H Crosby
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, UK
| | - Ugo Mayor
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, UPV/EHU, Leioa, Bizkaia, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Francesc Ventura
- Department of Physiological Sciences, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona (UB), C/ Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Spain
| | - Jose Luis Rosa
- Department of Physiological Sciences, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona (UB), C/ Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Spain.
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In memoriam: Huib Ovaa, the brain behind the formula (18/12/1973-19/05/2020). Semin Cell Dev Biol 2022; 132:1-4. [PMID: 35753908 DOI: 10.1016/j.semcdb.2022.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Progress in the mechanism of neuronal surface P antigen modulating hippocampal function and implications for autoimmune brain disease. Curr Opin Neurol 2022; 35:436-442. [PMID: 35674087 DOI: 10.1097/wco.0000000000001054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The aim of this study was to present a new regulation system in the hippocampus constituted by the neuronal surface P antigen (NSPA) and the tyrosine phosphatase PTPMEG/PTPN4, which provides mechanistic and therapeutic possibilities for cognitive dysfunction driven by antiribosomal P protein autoantibodies in patients with systemic lupus erythematosus (SLE). RECENT FINDINGS Mice models lacking the function of NSPA as an E3 ubiquitin ligase show impaired glutamatergic synaptic plasticity, decreased levels of NMDAR at the postsynaptic density in hippocampus and memory deficits. The levels of PTPMEG/PTPN4 are increased due to lower ubiquitination and proteasomal degradation, resulting in dephosphorylation of tyrosines that control endocytosis in GluN2 NMDAR subunits. Adult hippocampal neurogenesis (AHN) that normally contributes to memory processes is also defective in the absence of NSPA. SUMMARY NSPA function is crucial in memory processes controlling the stability of NMDAR at PSD through the ubiquitination of PTPMEG/PTPN4 and also through AHN. As anti-P autoantibodies reproduce the impairments of glutamatergic transmission, plasticity and memory performance seen in the absence of NSPA, it might be expected to perturb the NSPA/PTPMEG/PTPN4 pathway leading to hypofunction of NMDAR. This neuropathogenic mechanism contrasts with that of anti-NMDAR antibodies also involved in lupus cognitive dysfunction. Testing this hypothesis might open new therapeutic possibilities for cognitive dysfunction in SLE patients bearing anti-P autoantibodies.
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