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Smith DM, Aggarwal G, Niehoff ML, Jones SA, Banerjee S, Farr SA, Nguyen AD. Biochemical, Biomarker, and Behavioral Characterization of the Grn R493X Mouse Model of Frontotemporal Dementia. Mol Neurobiol 2024:10.1007/s12035-024-04190-9. [PMID: 38696065 DOI: 10.1007/s12035-024-04190-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 04/17/2024] [Indexed: 05/14/2024]
Abstract
Heterozygous loss-of-function mutations in the progranulin gene (GRN) are a major cause of frontotemporal dementia due to progranulin haploinsufficiency; complete deficiency of progranulin causes neuronal ceroid lipofuscinosis. Several progranulin-deficient mouse models have been generated, including both knockout mice and knockin mice harboring a common patient mutation (R493X). However, the GrnR493X mouse model has not been characterized completely. Additionally, while homozygous GrnR493X and Grn knockout mice have been extensively studied, data from heterozygous mice is still limited. Here, we performed more in-depth characterization of heterozygous and homozygous GrnR493X knockin mice, which includes biochemical assessments, behavioral studies, and analysis of fluid biomarkers. In the brains of homozygous GrnR493X mice, we found increased phosphorylated TDP-43 along with increased expression of lysosomal genes, markers of microgliosis and astrogliosis, pro-inflammatory cytokines, and complement factors. Heterozygous GrnR493X mice did not have increased TDP-43 phosphorylation but did exhibit limited increases in lysosomal and inflammatory gene expression. Behavioral studies found social and emotional deficits in GrnR493X mice that mirror those observed in Grn knockout mouse models, as well as impairment in memory and executive function. Overall, the GrnR493X knockin mouse model closely phenocopies Grn knockout models. Lastly, in contrast to homozygous knockin mice, heterozygous GrnR493X mice do not have elevated levels of fluid biomarkers previously identified in humans, including neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in both plasma and CSF. These results may help to inform pre-clinical studies that use this Grn knockin mouse model and other Grn knockout models.
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Affiliation(s)
- Denise M Smith
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA
| | - Geetika Aggarwal
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA
| | - Michael L Niehoff
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Veterans Affairs Medical Center, St. Louis, USA
| | - Spencer A Jones
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA
| | - Subhashis Banerjee
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA
| | - Susan A Farr
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA
- Veterans Affairs Medical Center, St. Louis, USA
| | - Andrew D Nguyen
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, USA.
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, USA.
- Institute for Translational Neuroscience, Saint Louis University, St. Louis, USA.
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2
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Aggarwal G, Banerjee S, Jones SA, Benchaar Y, Bélanger J, Sévigny M, Smith DM, Niehoff ML, Pavlack M, de Vera IMS, Petkau TL, Leavitt BR, Ling K, Jafar-Nejad P, Rigo F, Morley JE, Farr SA, Dutchak PA, Sephton CF, Nguyen AD. Antisense oligonucleotides targeting the miR-29b binding site in the GRN mRNA increase progranulin translation. J Biol Chem 2023; 299:105475. [PMID: 37981208 PMCID: PMC10755782 DOI: 10.1016/j.jbc.2023.105475] [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: 09/18/2023] [Revised: 10/13/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023] Open
Abstract
Heterozygous GRN (progranulin) mutations cause frontotemporal dementia (FTD) due to haploinsufficiency, and increasing progranulin levels is a major therapeutic goal. Several microRNAs, including miR-29b, negatively regulate progranulin protein levels. Antisense oligonucleotides (ASOs) are emerging as a promising therapeutic modality for neurological diseases, but strategies for increasing target protein levels are limited. Here, we tested the efficacy of ASOs as enhancers of progranulin expression by sterically blocking the miR-29b binding site in the 3' UTR of the human GRN mRNA. We found 16 ASOs that increase progranulin protein in a dose-dependent manner in neuroglioma cells. A subset of these ASOs also increased progranulin protein in iPSC-derived neurons and in a humanized GRN mouse model. In FRET-based assays, the ASOs effectively competed for miR-29b from binding to the GRN 3' UTR RNA. The ASOs increased levels of newly synthesized progranulin protein by increasing its translation, as revealed by polysome profiling. Together, our results demonstrate that ASOs can be used to effectively increase target protein levels by partially blocking miR binding sites. This ASO strategy may be therapeutically feasible for progranulin-deficient FTD as well as other conditions of haploinsufficiency.
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Affiliation(s)
- Geetika Aggarwal
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Subhashis Banerjee
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Spencer A Jones
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Yousri Benchaar
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Jasmine Bélanger
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Myriam Sévigny
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Denise M Smith
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Michael L Niehoff
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Veterans Affairs Medical Center, St Louis, Missouri, USA
| | - Monica Pavlack
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Ian Mitchelle S de Vera
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA
| | - Terri L Petkau
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, B.C. Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Blair R Leavitt
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, B.C. Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; Division of Neurology, Department of Medicine, University of British Columbia Hospital, Vancouver, British Columbia, Canada; Center for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Karen Ling
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - John E Morley
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Susan A Farr
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA; Veterans Affairs Medical Center, St Louis, Missouri, USA
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Andrew D Nguyen
- Division of Geriatric Medicine, Department of Internal Medicine, Saint Louis University School of Medicine, St Louis, Missouri, USA; Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA; Institute for Translational Neuroscience, Saint Louis University, St Louis, Missouri, USA.
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Gillett DA, Wallings RL, Uriarte Huarte O, Tansey MG. Progranulin and GPNMB: interactions in endo-lysosome function and inflammation in neurodegenerative disease. J Neuroinflammation 2023; 20:286. [PMID: 38037070 PMCID: PMC10688479 DOI: 10.1186/s12974-023-02965-w] [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: 09/22/2023] [Accepted: 11/21/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Alterations in progranulin (PGRN) expression are associated with multiple neurodegenerative diseases (NDs), including frontotemporal dementia (FTD), Alzheimer's disease (AD), Parkinson's disease (PD), and lysosomal storage disorders (LSDs). Recently, the loss of PGRN was shown to result in endo-lysosomal system dysfunction and an age-dependent increase in the expression of another protein associated with NDs, glycoprotein non-metastatic B (GPNMB). MAIN BODY It is unclear what role GPNMB plays in the context of PGRN insufficiency and how they interact and contribute to the development or progression of NDs. This review focuses on the interplay between these two critical proteins within the context of endo-lysosomal health, immune function, and inflammation in their contribution to NDs. SHORT CONCLUSION PGRN and GPNMB are interrelated proteins that regulate disease-relevant processes and may have value as therapeutic targets to delay disease progression or extend therapeutic windows.
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Affiliation(s)
- Drew A Gillett
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Rebecca L Wallings
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Oihane Uriarte Huarte
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Malú Gámez Tansey
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Life B, Bettio LE, Gantois I, Christie BR, Leavitt BR. Progranulin is an FMRP target that influences macroorchidism but not behaviour in a mouse model of Fragile X Syndrome. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 5:100094. [PMID: 37416094 PMCID: PMC10319828 DOI: 10.1016/j.crneur.2023.100094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 05/17/2023] [Accepted: 06/05/2023] [Indexed: 07/08/2023] Open
Abstract
A growing body of evidence has implicated progranulin in neurodevelopment and indicated that aberrant progranulin expression may be involved in neurodevelopmental disease. Specifically, increased progranulin expression in the prefrontal cortex has been suggested to be pathologically relevant in male Fmr1 knockout (Fmr1 KO) mice, a mouse model of Fragile X Syndrome (FXS). Further investigation into the role of progranulin in FXS is warranted to determine if therapies that reduce progranulin expression represent a viable strategy for treating patients with FXS. Several key knowledge gaps remain. The mechanism of increased progranulin expression in Fmr1 KO mice is poorly understood and the extent of progranulin's involvement in FXS-like phenotypes in Fmr1 KO mice has been incompletely explored. To this end, we have performed a thorough characterization of progranulin expression in Fmr1 KO mice. We find that the phenomenon of increased progranulin expression is post-translational and tissue-specific. We also demonstrate for the first time an association between progranulin mRNA and FMRP, suggesting that progranulin mRNA is an FMRP target. Subsequently, we show that progranulin over-expression in Fmr1 wild-type mice causes reduced repetitive behaviour engagement in females and mild hyperactivity in males but is largely insufficient to recapitulate FXS-associated behavioural, morphological, and electrophysiological abnormalities. Lastly, we determine that genetic reduction of progranulin expression on an Fmr1 KO background reduces macroorchidism but does not alter other FXS-associated behaviours or biochemical phenotypes.
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Affiliation(s)
- Benjamin Life
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6H 0B3, Canada
- BC Children's Hospital Research Institute, Vancouver, BC, V5Z 4H4, Canada
| | - Luis E.B. Bettio
- Division of Medical Sciences, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Ilse Gantois
- Department of Biochemistry, McGill University, Montreal, H3A 2T5, Quebec, Canada
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, H3A 2T5, Quebec, Canada
| | - Brian R. Christie
- Division of Medical Sciences, University of Victoria, Victoria, BC, V8P 5C2, Canada
- Island Medical Program, University of British Columbia, Victoria, BC, V8P 5C2, Canada
- Center for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Blair R. Leavitt
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6H 0B3, Canada
- BC Children's Hospital Research Institute, Vancouver, BC, V5Z 4H4, Canada
- Division of Neurology, Department of Medicine, University of British Columbia Hospital, Vancouver, BC, V6T 2B5, Canada
- Center for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Life B, Petkau TL, Cruz GNF, Navarro-Delgado EI, Shen N, Korthauer K, Leavitt BR. FTD-associated behavioural and transcriptomic abnormalities in 'humanized' progranulin-deficient mice: A novel model for progranulin-associated FTD. Neurobiol Dis 2023; 182:106138. [PMID: 37105261 DOI: 10.1016/j.nbd.2023.106138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023] Open
Abstract
Frontotemporal dementia (FTD) is an early onset dementia characterized by neuropathology and behavioural changes. A common genetic cause of FTD is haploinsufficiency of the gene progranulin (GRN). Mouse models of progranulin deficiency have provided insight into progranulin neurobiology, but the description of phenotypes with preclinical relevance has been limited in the currently available heterozygous progranulin-null mice. The identification of robust and reproducible FTD-associated behavioural, neuropathological, and biochemical phenotypes in progranulin deficient mice is a critical step in the preclinical development of therapies for FTD. In this work, we report the generation of a novel, 'humanized' mouse model of progranulin deficiency that expresses a single, targeted copy of human GRN in the absence of mouse progranulin. We also report the in-depth, longitudinal characterization of humanized progranulin-deficient mice and heterozygous progranulin-null mice over 18 months. Our analysis yielded several novel progranulin-dependent physiological and behavioural phenotypes, including increased marble burying, open field hyperactivity, and thalamic microgliosis in both models. RNAseq analysis of cortical tissue revealed an overlapping profile of transcriptomic dysfunction. Further transcriptomic analysis offers new insights into progranulin neurobiology. In sum, we have identified several consistent phenotypes in two independent mouse models of progranulin deficiency that are expected to be useful endpoints in the development of therapies for progranulin-deficient FTD. Furthermore, the presence of the human progranulin gene in the humanized progranulin-deficient mice will expedite the development of clinically translatable gene therapy strategies.
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Affiliation(s)
- Benjamin Life
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Terri L Petkau
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Giuliano N F Cruz
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Erick I Navarro-Delgado
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ning Shen
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Keegan Korthauer
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Division of Neurology, Department of Medicine, University of British Columbia Hospital, Vancouver, BC V6T 2B5, Canada; Center for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Amin S, Carling G, Gan L. New insights and therapeutic opportunities for progranulin-deficient frontotemporal dementia. Curr Opin Neurobiol 2022; 72:131-139. [PMID: 34826653 DOI: 10.1016/j.conb.2021.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/19/2021] [Indexed: 01/02/2023]
Abstract
Frontotemporal dementia (FTD) is the second most common form of dementia. It affects the frontal and temporal lobes of the brain and has a highly heterogeneous clinical representation with patients presenting with a wide range of behavioral, language, and executive dysfunctions. Etiology of FTD is complex and consists of both familial and sporadic cases. Heterozygous mutations in the GRN gene, resulting in GRN haploinsufficiency, cause progranulin (PGRN)-deficient FTD characterized with cytoplasmic mislocalization of TAR DNA-binding protein 43 kDa (TDP-43) aggregates. GRN codes for PGRN, a secreted protein that is also localized in the endolysosomes and plays a critical role in regulating lysosomal homeostasis. How PGRN deficiency modulates immunity and causes TDP-43 pathology and FTD-related neurodegeneration remains an active area of intense investigation. In the current review, we discuss some of the significant progress made in the past two years that links PGRN deficiency with microglial-associated neuroinflammation, TDP-43 pathology, and lysosomal dysfunction. We also review the opportunities and challenges toward developing therapies and biomarkers to treat PGRN-deficient FTD.
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Affiliation(s)
- Sadaf Amin
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Gillian Carling
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA; Neuroscience Graduate Program, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Li Gan
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA.
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Charif SE, Vassallu MF, Salvañal L, Igaz LM. Protein synthesis modulation as a therapeutic approach for amyotrophic lateral sclerosis and frontotemporal dementia. Neural Regen Res 2021; 17:1423-1430. [PMID: 34916412 PMCID: PMC8771112 DOI: 10.4103/1673-5374.330593] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Protein synthesis is essential for cells to perform life metabolic processes. Pathological alterations of protein content can lead to particular diseases. Cells have an intrinsic array of mechanisms and pathways that are activated when protein misfolding, accumulation, aggregation or mislocalization occur. Some of them (like the unfolded protein response) represent complex interactions between endoplasmic reticulum sensors and elongation factors that tend to increase expression of chaperone proteins and/or repress translation in order to restore protein homeostasis (also known as proteostasis). This is even more important in neurons, as they are very susceptible to harmful effects associated with protein overload and proteostatic mechanisms are less effective with age. Several neurodegenerative pathologies such as Alzheimer's, Parkinson's, and Huntington's diseases, amyotrophic lateral sclerosis and frontotemporal dementia exhibit a particular molecular signature of distinct, unbalanced protein overload. In amyotrophic lateral sclerosis and frontotemporal dementia, the majority of cases present intracellular inclusions of ubiquitinated transactive response DNA-binding protein of 43 kDa (TDP-43). TDP-43 is an RNA binding protein that participates in RNA metabolism, among other functions. Dysregulation of TDP-43 (e.g. aggregation and mislocalization) can dramatically affect neurons, and this has been linked to disease development. Expression of amyotrophic lateral sclerosis/frontotemporal dementia TDP-43-related mutations in cellular and animal models has been shown to recapitulate key features of the amyotrophic lateral sclerosis/frontotemporal dementia disease spectrum. These variants can be causative of degeneration onset and progression. Most neurodegenerative diseases (including amyotrophic lateral sclerosis and frontotemporal dementia) have no cure at the moment; however, modulating translation has recently emerged as an attractive approach that can be performed at several steps (i.e. regulating activation of initiation and elongation factors, inhibiting unfolded protein response activation or inducing chaperone expression and activity). This review focuses on the features of protein imbalance in neurodegenerative disorders and the relevance of developing therapeutical compounds aiming at restoring proteostasis. We strive to highlight the importance of research on drugs that, not only restore protein imbalance without compromising translational activity of cells, but are also as safe as possible for the patients.
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Affiliation(s)
- Santiago E Charif
- IFIBIO Houssay, Grupo de Neurociencia de Sistemas, Facultad de Medicina, Universidad de Buenos Aires -CONICET, Buenos Aires, Argentina
| | - M Florencia Vassallu
- IFIBIO Houssay, Grupo de Neurociencia de Sistemas, Facultad de Medicina, Universidad de Buenos Aires -CONICET, Buenos Aires, Argentina
| | - Lara Salvañal
- IFIBIO Houssay, Grupo de Neurociencia de Sistemas, Facultad de Medicina, Universidad de Buenos Aires -CONICET, Buenos Aires, Argentina
| | - Lionel M Igaz
- IFIBIO Houssay, Grupo de Neurociencia de Sistemas, Facultad de Medicina, Universidad de Buenos Aires -CONICET, Buenos Aires, Argentina
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