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Tsitkov S, Valentine K, Kozareva V, Donde A, Frank A, Lei S, E Van Eyk J, Finkbeiner S, Rothstein JD, Thompson LM, Sareen D, Svendsen CN, Fraenkel E. Disease related changes in ATAC-seq of iPSC-derived motor neuron lines from ALS patients and controls. Nat Commun 2024; 15:3606. [PMID: 38697975 PMCID: PMC11066062 DOI: 10.1038/s41467-024-47758-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/09/2024] [Indexed: 05/05/2024] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS), like many other neurodegenerative diseases, is highly heritable, but with only a small fraction of cases explained by monogenic disease alleles. To better understand sporadic ALS, we report epigenomic profiles, as measured by ATAC-seq, of motor neuron cultures derived from a diverse group of 380 ALS patients and 80 healthy controls. We find that chromatin accessibility is heavily influenced by sex, the iPSC cell type of origin, ancestry, and the inherent variance arising from sequencing. Once these covariates are corrected for, we are able to identify ALS-specific signals in the data. Additionally, we find that the ATAC-seq data is able to predict ALS disease progression rates with similar accuracy to methods based on biomarkers and clinical status. These results suggest that iPSC-derived motor neurons recapitulate important disease-relevant epigenomic changes.
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Affiliation(s)
- Stanislav Tsitkov
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kelsey Valentine
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Velina Kozareva
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aneesh Donde
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aaron Frank
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Susan Lei
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jennifer E Van Eyk
- Advanced Clinical Biosystems Research Institute, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, USA
- Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA, USA
- Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA, USA
| | - Dhruv Sareen
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- The Board of Governors Regenerative Medicine Institute and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Clive N Svendsen
- The Board of Governors Regenerative Medicine Institute and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ernest Fraenkel
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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2
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Elsasser S, Elia LP, Morimoto RI, Powers ET, Finley D, Costa B, Budron M, Tokuno Z, Wang S, Iyer RG, Barth B, Mockler E, Finkbeiner S, Gestwicki JE, Richardson RAK, Stoeger T, Tan EP, Xiao Q, Cole CM, Massey LA, Garza D, Kelly JW, Rainbolt TK, Chou CC, Masto VB, Frydman J, Nixon RA. A Comprehensive Enumeration of the Human Proteostasis Network. 2. Components of the Autophagy-Lysosome Pathway. bioRxiv 2023:2023.03.22.533675. [PMID: 36993380 PMCID: PMC10055369 DOI: 10.1101/2023.03.22.533675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The condition of having a healthy, functional proteome is known as protein homeostasis, or proteostasis. Establishing and maintaining proteostasis is the province of the proteostasis network, approximately 2,700 components that regulate protein synthesis, folding, localization, and degradation. The proteostasis network is a fundamental entity in biology that is essential for cellular health and has direct relevance to many diseases of protein conformation. However, it is not well defined or annotated, which hinders its functional characterization in health and disease. In this series of manuscripts, we aim to operationally define the human proteostasis network by providing a comprehensive, annotated list of its components. We provided in a previous manuscript a list of chaperones and folding enzymes as well as the components that make up the machineries for protein synthesis, protein trafficking into and out of organelles, and organelle-specific degradation pathways. Here, we provide a curated list of 838 unique high-confidence components of the autophagy-lysosome pathway, one of the two major protein degradation systems in human cells.
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Affiliation(s)
- Suzanne Elsasser
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Lisa P Elia
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Richard I Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL, USA
| | - Evan T Powers
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Beatrice Costa
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Maher Budron
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Zachary Tokuno
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Shijie Wang
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Rajshri G Iyer
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Bianca Barth
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Eric Mockler
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
| | - Steve Finkbeiner
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA, USA
- The J. David Gladstone Institutes, San Francisco, CA, USA
- Departments of Neurology and Physiology, UCSF, San Francisco, CA, USA
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
- Institute for Neurodegenerative Disease, University of California San Francisco, San Francisco, CA, USA
| | - Reese A K Richardson
- Center for Genetic Medicine, Northwestern University, Chicago, IL, USA
- Northwestern Institute on Complex Systems (NICO), Northwestern University, Evanston, IL, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL USA
| | - Thomas Stoeger
- Center for Genetic Medicine, Northwestern University, Chicago, IL, USA
- Northwestern Institute on Complex Systems (NICO), Northwestern University, Evanston, IL, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL USA
| | - Ee Phie Tan
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Qiang Xiao
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Christian M Cole
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Lynée A Massey
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Dan Garza
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
| | - Jeffery W Kelly
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA USA
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - T Kelly Rainbolt
- Department of Biology and Genetics, Stanford University, Stanford, CA, USA
| | - Ching-Chieh Chou
- Department of Biology and Genetics, Stanford University, Stanford, CA, USA
| | - Vincent B Masto
- Department of Biology and Genetics, Stanford University, Stanford, CA, USA
| | - Judith Frydman
- Department of Biology and Genetics, Stanford University, Stanford, CA, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
- Department of Psychiatry, New York University Langone Health, New York, NY, USA
- Department of Cell Biology, New York University Langone Health, New York, NY, USA
- NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA
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3
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Barbé L, Finkbeiner S. Genetic and Epigenetic Interplay Define Disease Onset and Severity in Repeat Diseases. Front Aging Neurosci 2022; 14:750629. [PMID: 35592702 PMCID: PMC9110800 DOI: 10.3389/fnagi.2022.750629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Repeat diseases, such as fragile X syndrome, myotonic dystrophy, Friedreich ataxia, Huntington disease, spinocerebellar ataxias, and some forms of amyotrophic lateral sclerosis, are caused by repetitive DNA sequences that are expanded in affected individuals. The age at which an individual begins to experience symptoms, and the severity of disease, are partially determined by the size of the repeat. However, the epigenetic state of the area in and around the repeat also plays an important role in determining the age of disease onset and the rate of disease progression. Many repeat diseases share a common epigenetic pattern of increased methylation at CpG islands near the repeat region. CpG islands are CG-rich sequences that are tightly regulated by methylation and are often found at gene enhancer or insulator elements in the genome. Methylation of CpG islands can inhibit binding of the transcriptional regulator CTCF, resulting in a closed chromatin state and gene down regulation. The downregulation of these genes leads to some disease-specific symptoms. Additionally, a genetic and epigenetic interplay is suggested by an effect of methylation on repeat instability, a hallmark of large repeat expansions that leads to increasing disease severity in successive generations. In this review, we will discuss the common epigenetic patterns shared across repeat diseases, how the genetics and epigenetics interact, and how this could be involved in disease manifestation. We also discuss the currently available stem cell and mouse models, which frequently do not recapitulate epigenetic patterns observed in human disease, and propose alternative strategies to study the role of epigenetics in repeat diseases.
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Affiliation(s)
- Lise Barbé
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
- *Correspondence: Steve Finkbeiner,
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4
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Stormo AE, Shavarebi F, FitzGibbon M, Earley EM, Ahrendt H, Lum LS, Verschueren E, Swaney DL, Skibinski G, Ravisankar A, van Haren J, Davis EJ, Johnson JR, Von Dollen J, Balen C, Porath J, Crosio C, Mirescu C, Iaccarino C, Dauer WT, Nichols RJ, Wittmann T, Cox TC, Finkbeiner S, Krogan NJ, Oakes SA, Hiniker A. The E3 ligase TRIM1 ubiquitinates LRRK2 and controls its localization, degradation, and toxicity. J Cell Biol 2022; 221:e202010065. [PMID: 35266954 PMCID: PMC8919618 DOI: 10.1083/jcb.202010065] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/26/2021] [Accepted: 01/04/2022] [Indexed: 11/22/2022] Open
Abstract
Missense mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of familial Parkinson's disease (PD); however, pathways regulating LRRK2 subcellular localization, function, and turnover are not fully defined. We performed quantitative mass spectrometry-based interactome studies to identify 48 novel LRRK2 interactors, including the microtubule-associated E3 ubiquitin ligase TRIM1 (tripartite motif family 1). TRIM1 recruits LRRK2 to the microtubule cytoskeleton for ubiquitination and proteasomal degradation by binding LRRK2911-919, a nine amino acid segment within a flexible interdomain region (LRRK2853-981), which we designate the "regulatory loop" (RL). Phosphorylation of LRRK2 Ser910/Ser935 within LRRK2 RL influences LRRK2's association with cytoplasmic 14-3-3 versus microtubule-bound TRIM1. Association with TRIM1 modulates LRRK2's interaction with Rab29 and prevents upregulation of LRRK2 kinase activity by Rab29 in an E3-ligase-dependent manner. Finally, TRIM1 rescues neurite outgrowth deficits caused by PD-driving mutant LRRK2 G2019S. Our data suggest that TRIM1 is a critical regulator of LRRK2, controlling its degradation, localization, binding partners, kinase activity, and cytotoxicity.
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Affiliation(s)
- Adrienne E.D. Stormo
- Departments of Pathology, University of California San Francisco, San Francisco, CA
| | - Farbod Shavarebi
- Department of Pathology, University of California San Diego, San Diego, CA
| | - Molly FitzGibbon
- Department of Pathology, University of California San Diego, San Diego, CA
| | - Elizabeth M. Earley
- Departments of Pathology, University of California San Francisco, San Francisco, CA
| | - Hannah Ahrendt
- Department of Pathology, University of California San Diego, San Diego, CA
| | - Lotus S. Lum
- Departments of Pathology, University of California San Francisco, San Francisco, CA
| | - Erik Verschueren
- Departments of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA
| | - Danielle L. Swaney
- Departments of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA
| | - Gaia Skibinski
- Taube/Koret Center for Neurodegenerative Disease Research, J. David Gladstone Institutes, San Francisco, CA
- Center for Systems and Therapeutics, J. David Gladstone Institutes, San Francisco, CA
| | - Abinaya Ravisankar
- Taube/Koret Center for Neurodegenerative Disease Research, J. David Gladstone Institutes, San Francisco, CA
- Center for Systems and Therapeutics, J. David Gladstone Institutes, San Francisco, CA
| | - Jeffrey van Haren
- Departments of Cell and Tissue Biology, University of California San Francisco, San Francisco, CA
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | - Emily J. Davis
- Departments of Pathology, University of California San Francisco, San Francisco, CA
| | - Jeffrey R. Johnson
- Departments of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA
| | - John Von Dollen
- Departments of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA
| | - Carson Balen
- Department of Pathology, University of California San Diego, San Diego, CA
| | - Jacob Porath
- Department of Pathology, University of California San Diego, San Diego, CA
| | - Claudia Crosio
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | | | - Ciro Iaccarino
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - William T. Dauer
- Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX
- Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Torsten Wittmann
- Departments of Cell and Tissue Biology, University of California San Francisco, San Francisco, CA
| | - Timothy C. Cox
- Department of Oral and Craniofacial Sciences, School of Medicine, University of Missouri Kansas City, Kansas City, MO
- School of Dentistry and Department of Pediatrics, School of Medicine, University of Missouri Kansas City, Kansas City, MO
| | - Steve Finkbeiner
- Departments of Neurology, University of California San Francisco, San Francisco, CA
- Departments of Physiology, University of California San Francisco, San Francisco, CA
- Taube/Koret Center for Neurodegenerative Disease Research, J. David Gladstone Institutes, San Francisco, CA
- Center for Systems and Therapeutics, J. David Gladstone Institutes, San Francisco, CA
| | - Nevan J. Krogan
- Departments of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA
- Center for Systems and Therapeutics, J. David Gladstone Institutes, San Francisco, CA
| | - Scott A. Oakes
- Departments of Pathology, University of California San Francisco, San Francisco, CA
- Department of Pathology, University of Chicago, Chicago, IL
| | - Annie Hiniker
- Department of Pathology, University of California San Diego, San Diego, CA
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5
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Abstract
Huntington's disease (HD) is a neurodegenerative disease that results in motor and cognitive dysfunction, leading to early death. HD is caused by an expansion of CAG repeats in the huntingtin gene (HTT). Here, we review the mouse models of HD. They have been used extensively to better understand the molecular and cellular basis of disease pathogenesis as well as to provide non-human subjects to test the efficacy of potential therapeutics. The first and best-studied in vivo rodent model of HD is the R6/2 mouse, in which a transgene containing the promoter and exon 1 fragment of human HTT with 150 CAG repeats was inserted into the mouse genome. R6/2 mice express rapid, robust behavioral pathologies and display a number of degenerative abnormalities in neuronal populations most vulnerable in HD. The first conditional full-length mutant huntingtin (mHTT) mouse model of HD was the bacterial artificial chromosome (BAC) transgenic mouse model of HD (BACHD), which expresses human full-length mHTT with a mixture of 97 CAG-CAA repeats under the control of endogenous HTT regulatory machinery. It has been useful in identifying the role of mHTT in specific neuronal populations in degenerative processes. In the knock-in (KI) model of HD, the expanded human CAG repeats and human exon 1 are inserted into the mouse Htt locus, so a chimera of the full-length mouse protein with the N-terminal human portion is expressed. Many of aspects of the pathology and behavioral deficits in the KI model better mimic disease characteristics found in HD patients than other models. Accordingly, some have proposed that these mice may be preferable models of the disease over others. Indeed, as our understanding of HD advances, so will the design of animal models to test and develop HD therapies.
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Affiliation(s)
- Julia Kaye
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, USA
| | - Terry Reisine
- Independent Scientific Consultant, Santa Cruz, CA, USA
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, USA
- Taube/Koret Center for Neurodegenerative Disease Research, Gladstone Institutes, San Francisco, CA, USA
- Department of Neurology and Physiology, University of California, San Francisco, CA, USA
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6
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Reed X, Cobb MM, Skinbinski G, Roosen D, Kaganovich A, Ding J, Finkbeiner S, Cookson MR. Transcriptional signatures in iPSC-derived neurons are reproducible across labs when differentiation protocols are closely matched. Stem Cell Res 2021; 56:102558. [PMID: 34626895 PMCID: PMC8655646 DOI: 10.1016/j.scr.2021.102558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 11/29/2022] Open
Abstract
Reproducibility of expression patterns in iPSC-derived cells from different labs is an important first step in ensuring replication of biochemical or functional assays that are performed in different labs. Here we show that reproducible gene expression patterns from iPSCs and iPSC-derived neurons matured and collected at two separate laboratory locations can be achieved by closely matching protocols and reagents. While there are significant differences in gene expression between iPSCs and differentiated neurons, as well as between different donor lines of the same cell type, transcriptional changes that vary with laboratory sites are relatively small. These results suggest that making great efforts to match protocols, reagents and technical methods between labs may improve the reproducibility of iPSC-derived cell models.
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Affiliation(s)
- Xylena Reed
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Melanie M Cobb
- Center for Systems and Therapeutics & Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA, 94158, USA
| | - Gaia Skinbinski
- Center for Systems and Therapeutics & Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA, 94158, USA
| | - Dorien Roosen
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alice Kaganovich
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinhui Ding
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Steve Finkbeiner
- Center for Systems and Therapeutics & Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA, 94158, USA; Departments of Neurology and Physiology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Mark R Cookson
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
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7
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Li H, Doric Z, Berthet A, Jorgens DM, Nguyen MK, Hsieh I, Margulis J, Fang R, Debnath J, Sesaki H, Finkbeiner S, Huang E, Nakamura K. Longitudinal tracking of neuronal mitochondria delineates PINK1/Parkin-dependent mechanisms of mitochondrial recycling and degradation. Sci Adv 2021; 7:7/32/eabf6580. [PMID: 34362731 PMCID: PMC8346224 DOI: 10.1126/sciadv.abf6580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Altered mitochondrial quality control and dynamics may contribute to neurodegenerative diseases, including Parkinson's disease, but we understand little about these processes in neurons. We combined time-lapse microscopy and correlative light and electron microscopy to track individual mitochondria in neurons lacking the fission-promoting protein dynamin-related protein 1 (Drp1) and delineate the kinetics of PINK1-dependent pathways of mitochondrial quality control. Depolarized mitochondria recruit Parkin to the outer mitochondrial membrane, triggering autophagosome formation, rapid lysosomal fusion, and Parkin redistribution. Unexpectedly, these mitolysosomes are dynamic and persist for hours. Some are engulfed by healthy mitochondria, and others are deacidified before bursting. In other cases, Parkin is directly recruited to the matrix of polarized mitochondria. Loss of PINK1 blocks Parkin recruitment, causes LC3 accumulation within mitochondria, and exacerbates Drp1KO toxicity to dopamine neurons. These results define a distinct neuronal mitochondrial life cycle, revealing potential mechanisms of mitochondrial recycling and signaling relevant to neurodegeneration.
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Affiliation(s)
- Huihui Li
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Zak Doric
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Amandine Berthet
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Danielle M Jorgens
- Electron Microscope Laboratory, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Mai K Nguyen
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Ivy Hsieh
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Julia Margulis
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Rebecca Fang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jayanta Debnath
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
- Graduate Program in Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Hiromi Sesaki
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Steve Finkbeiner
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
- Graduate Program in Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Center for Systems and Therapeutics, Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eric Huang
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
- Graduate Program in Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA.
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
- Graduate Program in Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
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8
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Zhang X, Abels ER, Redzic JS, Margulis J, Finkbeiner S, Breakefield XO. Potential Transfer of Polyglutamine and CAG-Repeat RNA in Extracellular Vesicles in Huntington's Disease: Background and Evaluation in Cell Culture. Cell Mol Neurobiol 2016; 36:459-70. [PMID: 26951563 DOI: 10.1007/s10571-016-0350-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/13/2016] [Indexed: 12/31/2022]
Abstract
In Huntington's disease (HD) the imperfect expanded CAG repeat in the first exon of the HTT gene leads to the generation of a polyglutamine (polyQ) protein, which has some neuronal toxicity, potentially mollified by formation of aggregates. Accumulated research, reviewed here, implicates both the polyQ protein and the expanded repeat RNA in causing toxicity leading to neurodegeneration in HD. Different theories have emerged as to how the neurodegeneration spreads throughout the brain, with one possibility being the transport of toxic protein and RNA in extracellular vesicles (EVs). Most cell types in the brain release EVs and these have been shown to contain neurodegenerative proteins in the case of prion protein and amyloid-beta peptide. In this study, we used a model culture system with an overexpression of HTT-exon 1 polyQ-GFP constructs in human 293T cells and found that the EVs did incorporate both the polyQ-GFP protein and expanded repeat RNA. Striatal mouse neural cells were able to take up these EVs with a consequent increase in the green fluorescent protein (GFP) and polyQ-GFP RNAs, but with no evidence of uptake of polyQ-GFP protein or any apparent toxicity, at least over a relatively short period of exposure. A differentiated striatal cell line expressing endogenous levels of Hdh mRNA containing the expanded repeat incorporated more of this mRNA into EVs as compared to similar cells expressing this mRNA with a normal repeat length. These findings support the potential of EVs to deliver toxic expanded trinucleotide repeat RNAs from one cell to another, but further work will be needed to evaluate potential EV and cell-type specificity of transfer and effects of long-term exposure. It seems likely that expanded HD-associated repeat RNA may appear in biofluids and may have use as biomarkers of disease state and response to therapy.
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Affiliation(s)
- Xuan Zhang
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital-East, 13th Street, Building 149, Charlestown, MA, 02129, USA.,Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.,Center for NeuroDiscovery, Harvard Medical School, Boston, MA, USA
| | - Erik R Abels
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital-East, 13th Street, Building 149, Charlestown, MA, 02129, USA.,Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.,Center for NeuroDiscovery, Harvard Medical School, Boston, MA, USA
| | - Jasmina S Redzic
- Department of Pharmaceutical Sciences, University of Colorado Denver Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Julia Margulis
- Gladstone Institute of Neurological Disease and the Departments of Neurology and Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Steve Finkbeiner
- Gladstone Institute of Neurological Disease and the Departments of Neurology and Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Xandra O Breakefield
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital-East, 13th Street, Building 149, Charlestown, MA, 02129, USA. .,Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA. .,Center for NeuroDiscovery, Harvard Medical School, Boston, MA, USA.
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9
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Mattis VB, Svendsen SP, Ebert A, Svendsen CN, King AR, Casale M, Winokur ST, Batugedara G, Vawter M, Donovan PJ, Lock LF, Thompson LM, Zhu Y, Fossale E, Atwal RS, Gillis T, Mysore J, Li JH, Seong IS, Shen Y, Chen X, Wheeler VC, MacDonald ME, Gusella JF, Akimov S, Arbez N, Juopperi T, Ratovitski T, Chiang JH, Kim WR, Chighladze E, Watkin E, Zhong C, Makri G, Cole RN, Margolis RL, Song H, Ming G, Ross CA, Kaye JA, Daub A, Sharma P, Mason AR, Finkbeiner S, Yu J, Thomson JA, Rushton D, Brazier SP, Battersby AA, Redfern A, Tseng HE, Harrison AW, Kemp PJ, Allen ND, Onorati M, Castiglioni V, Cattaneo E, Arjomand J. A11 Induced pluripotent stem cells for basic and translational research on HD. J Neurol Neurosurg Psychiatry 2012. [DOI: 10.1136/jnnp-2012-303524.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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10
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Fuchs HD, Rosenbauer M, Brandt MS, Ernst S, Finkbeiner S, Stutzmann M, Syassen K, Weber J, Queisser HJ, Cardona M. Visible Luminescence from Porous Silicon and Siloxene: Recent Results. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-283-203] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe optical properties of porous Si (p-Si) are compared to those of siloxene and its derivatives in order to gain more insight into the mechanism of the luminescence observed in p-Si. We report new results of photoluminescence (PL), photoluminescence excitation (PLE), time-dependent and pressure-dependent photoluminescence, and optically detected magnetic resonance (ODMR). Important information about the structural, electronic, and microscopic nature of the two classes of materials are deduced from these experiments. Annealed siloxene and p-Si show very similar properties, suggesting that siloxene-related structures, e.g. electrically isolated Si6-rings, might be responsible for the luminescence in p-Si. The Si-planes in as-prepared siloxene, with their green luminescence, are metastable and are readily oxidized into red-luminescent siloxene configurations.
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11
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Sathasivam K, Lane A, Legleiter J, Warley A, Woodman B, Finkbeiner S, Paganetti P, Muchowski PJ, Wilson S, Bates GP. Identical oligomeric and fibrillar structures captured from the brains of R6/2 and knock-in mouse models of Huntington's disease. Hum Mol Genet 2010; 19:65-78. [PMID: 19825844 PMCID: PMC2792149 DOI: 10.1093/hmg/ddp467] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Huntington's disease (HD) is a late-onset neurodegenerative disorder that is characterized neuropathologically by the presence of neuropil aggregates and nuclear inclusions. However, the profile of aggregate structures that are present in the brains of HD patients or of HD mouse models and the relative contribution of specific aggregate structures to disease pathogenesis is unknown. We have used the Seprion ligand to develop a highly sensitive enzyme-linked immunosorbent assay (ELISA)-based method for quantifying aggregated polyglutamine in tissues from HD mouse models. We used a combination of electron microscopy, atomic force microscopy (AFM) and sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) to investigate the aggregate structures isolated by the ligand. We found that the oligomeric, proto-fibrillar and fibrillar aggregates extracted from the brains of R6/2 and HdhQ150 knock-in mice were remarkably similar. Using AFM, we determined that the nanometre globular oligomers isolated from the brains of both mouse models have dimensions identical to those generated from recombinant huntingtin exon 1 proteins. Finally, antibodies that detect exon 1 Htt epitopes differentially recognize the ligand-captured material on SDS–PAGE gels. The Seprion-ligand ELISA provides an assay with good statistical power for use in preclinical pharmacodynamic therapeutic trials or to assess the effects of the genetic manipulation of potential therapeutic targets on aggregate load. This, together with the ability to identify a spectrum of aggregate species in HD mouse tissues, will contribute to our understanding of how these structures relate to the pathogenesis of HD and whether their formation can be manipulated for therapeutic benefit.
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Affiliation(s)
- Kirupa Sathasivam
- Department of Medical and Molecular Genetics, King's College London School of Medicine, King's College London, 8th Floor Tower Wing, Guy's Tower, Great Maze Pond, London, UK
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12
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Landles C, Sathasivam K, Weiss A, Woodman B, Moffitt H, Finkbeiner S, Sun B, Gafni J, Ellerby LM, Trottier Y, Richards WG, Osmand A, Paganetti P, Bates GP. Proteolysis of mutant huntingtin produces an exon 1 fragment that accumulates as an aggregated protein in neuronal nuclei in Huntington disease. J Biol Chem 2010; 285:8808-23. [PMID: 20086007 DOI: 10.1074/jbc.m109.075028] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Huntingtin proteolysis has been implicated in the molecular pathogenesis of Huntington disease (HD). Despite an intense effort, the identity of the pathogenic smallest N-terminal fragment has not been determined. Using a panel of anti-huntingtin antibodies, we employed an unbiased approach to generate proteolytic cleavage maps of mutant and wild-type huntingtin in the HdhQ150 knock-in mouse model of HD. We identified 14 prominent N-terminal fragments, which, in addition to the full-length protein, can be readily detected in cytoplasmic but not nuclear fractions. These fragments were detected at all ages and are not a consequence of the pathogenic process. We demonstrated that the smallest fragment is an exon 1 huntingtin protein, known to contain a potent nuclear export signal. Prior to the onset of behavioral phenotypes, the exon 1 protein, and possibly other small fragments, accumulate in neuronal nuclei in the form of a detergent insoluble complex, visualized as diffuse granular nuclear staining in tissue sections. This methodology can be used to validate the inhibition of specific proteases as therapeutic targets for HD by pharmacological or genetic approaches.
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Affiliation(s)
- Christian Landles
- Department Medical and Molecular Genetics, King's College London School of Medicine, King's College London, London SE1 9RT, United Kingdom
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13
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Legleiter J, Lotz GP, Miller J, Ko J, Ng C, Williams GL, Finkbeiner S, Patterson PH, Muchowski PJ. Monoclonal antibodies recognize distinct conformational epitopes formed by polyglutamine in a mutant huntingtin fragment. J Biol Chem 2009; 284:21647-58. [PMID: 19491400 DOI: 10.1074/jbc.m109.016923] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by an expansion of a polyglutamine (polyQ) domain in the N-terminal region of huntingtin (htt). PolyQ expansion above 35-40 results in disease associated with htt aggregation into inclusion bodies. It has been hypothesized that expanded polyQ domains adopt multiple potentially toxic conformations that belong to different aggregation pathways. Here, we used atomic force microscopy to analyze the effect of a panel of anti-htt antibodies (MW1-MW5, MW7, MW8, and 3B5H10) on aggregate formation and the stability of a mutant htt-exon1 fragment. Two antibodies, MW7 (polyproline-specific) and 3B5H10 (polyQ-specific), completely inhibited fibril formation and disaggregated preformed fibrils, whereas other polyQ-specific antibodies had widely varying effects on aggregation. These results suggest that expanded polyQ domains adopt multiple conformations in solution that can be readily distinguished by monoclonal antibodies, which has important implications for understanding the structural basis for polyQ toxicity and the development of intrabody-based therapeutics for HD.
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Affiliation(s)
- Justin Legleiter
- Gladstone Institute of Neurological Disease, University of California, San Francisco, California 94158, USA
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14
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Finkbeiner S. New Roles for Introns: Sites of Combinatorial Regulation of Ca2+- and Cyclic AMP-Dependent Gene Transcription. Sci Signal 2001. [DOI: 10.1126/scisignal.942001pe1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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15
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Abstract
Because some proteins can facilitate cell division or the expression of many genes simultaneously, it comes as no surprise that the expression of very important gene products is a tightly controlled process. Although gene expression is often thought of in terms of complexes of transcription factors binding to promoter elements, some studies indicate that intronic DNA sequences may also regulate gene expression. Finkbeiner examines recent work by Schlegel and colleagues demonstrating that sequences within the first intron of the c-fos gene help to regulate Fos expression under different conditions.
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Affiliation(s)
- S Finkbeiner
- the Gladstone Institute of Neurological Disease, Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA 94143, USA.
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16
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Abstract
Results from several laboratories have suggested that peptide factors known as neurotrophins may play roles coupling changes in synaptic activity to lasting changes in synaptic function. Consistent with this idea, increases in synaptic activity and intracellular calcium induce the expression of the gene that encodes the neurotrophin, brain-derived neurotrophic factor. Recently, a pathway has been elucidated in neurons by which the influx of extracellular calcium evokes brain-derived neurotrophic factor transcription (BDNF). Calcium activates BDNF transcription through two adjacent calcium response elements within one of the promoters of the BDNF gene. One of the two elements binds to the cyclic adenosine monophosphate (AMP) response element binding protein (CREB) transcription factor, and interfering with CREB or related family members inhibits calcium-dependent BDNF transcription. This review focuses on the mechanisms by which calcium influx regulates brain-derived neurotrophic factor expression and the implications that these results have for potential roles of neurotrophins in synaptic function.
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Affiliation(s)
- S Finkbeiner
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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17
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Affiliation(s)
- S Finkbeiner
- Gladstone Institute of Neurological Disease, Department of Neurology, University of California, San Francisco 94143, USA.
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18
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Curtis J, Finkbeiner S. Sending signals from the synapse to the nucleus: possible roles for CaMK, Ras/ERK, and SAPK pathways in the regulation of synaptic plasticity and neuronal growth. J Neurosci Res 1999; 58:88-95. [PMID: 10491574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The ability to learn and form memories depends on specific patterns of synaptic activity and is in part transcription dependent. However, the signal transduction pathways that connect signals generated at synapses with transcriptional responses in the nucleus are not well understood. In the present report, we discuss three signal transduction pathways: the Ca(2+)/calmodulin-dependent kinase (CaMK) pathway, the Ras/ERK pathway, and the SAPK pathways that might function to couple synaptic activity to long-term adaptive responses, in part through the regulation of new gene expression. Evidence suggests that these pathways become activated in response to stimuli that regulate synaptic function such as the influx of extracellular Ca(2+) and certain neurotrophin growth factors such as brain-derived neurotrophic factor. Once activated, the CaMK, Ras/ERK, and SAPK pathways lead to the phosphorylation and activation of transcription factors in the nucleus such as the cyclic AMP response element binding protein (CREB). Genes regulated by CREB or other transcription factor targets of the CaMK, Ras/ERK, and SAPK pathways could mediate important adaptive responses to changes in synaptic activity such as changes in synaptic strength and the regulation of neuronal survival and death.
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Affiliation(s)
- J Curtis
- Division of Neuroscience, Department of Neurology, Harvard Medical School, Children's Hospital, Boston, Massachusetts, USA
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19
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Saudou F, Finkbeiner S, Devys D, Greenberg ME. Huntingtin acts in the nucleus to induce apoptosis but death does not correlate with the formation of intranuclear inclusions. Cell 1998; 95:55-66. [PMID: 9778247 DOI: 10.1016/s0092-8674(00)81782-1] [Citation(s) in RCA: 1140] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The mechanisms by which mutant huntingtin induces neurodegeneration were investigated using a cellular model that recapitulates features of neurodegeneration seen in Huntington's disease. When transfected into cultured striatal neurons, mutant huntingtin induces neurodegeneration by an apoptotic mechanism. Antiapoptotic compounds or neurotrophic factors protected neurons against mutant huntingtin. Blocking nuclear localization of mutant huntingtin suppressed its ability to form intranuclear inclusions and to induce neurodegeneration. However, the presence of inclusions did not correlate with huntingtin-induced death. The exposure of mutant huntingtin-transfected striatal neurons to conditions that suppress the formation of inclusions resulted in an increase in mutant huntingtin-induced death. These findings suggest that mutant huntingtin acts within the nucleus to induce neurodegeneration. However, intranuclear inclusions may reflect a cellular mechanism to protect against huntingtin-induced cell death.
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Affiliation(s)
- F Saudou
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Finkbeiner S, Greenberg ME. Ca2+ channel-regulated neuronal gene expression. J Neurobiol 1998; 37:171-89. [PMID: 9777740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Neuronal activity is required for the survival of specific populations of neurons, for the proper synaptic organization of the visual and somatosensory cortex, and for learning and memory. The biochemical mechanisms that couple brief neuronal activity to rapid and lasting adaptive changes within the nervous system are poorly understood. Over a decade ago, it was first shown that mimicking neuronal activity by membrane depolarization rapidly induced the expression of a class of genes known as immediate early genes. Subsequently, it has been shown that neuronal activity triggers a temporal sequence of gene expression that has been suggested to play a role in mediating long-term adaptive responses. A major mechanism coupling neuronal electrical activity and the intracellular biochemical processes that culminate in gene expression is Ca2+ influx through plasma membrane Ca2+ channels. In this review, we delineate some of the reported mechanisms by which Ca2+ regulates gene expression: from its ability to activate specific intracellular signal transduction pathways to its ability to regulate the initiation, elongation, and translation of RNA transcripts. We will discuss some known mechanisms by which different patterns of Ca2+ influx, or Ca2+ influx through different types of channel, could generate distinct patterns of gene expression and how our understanding of Ca2+-regulated gene expression relates to larger questions of activity-dependent nervous system function.
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Affiliation(s)
- S Finkbeiner
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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21
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Abstract
Learning, making memories, and forgetting are thought to require changes in the strengths of connections between neurons. Such changes in synaptic strength occur in two phases: an early phase that is likely mediated by covalent modifications to existing proteins, and a delayed phase that depends on new gene expression and protein synthesis. However, the biochemical mechanisms by which neuronal activity leads to changes in synaptic strength are poorly understood. Recently, it has been shown that animals that lack Ras guanine nucleotide releasing factor (Ras-GRF), a Ca(2+)-dependent activator of the small GTP-binding protein, Ras, do not learn fear responses normally, although other types of learning appear normal. These animals show defects in the delayed phase of memory formation within the neuronal circuit that mediates fear conditioning. This paper suggests that Ras-GRF couples synaptic activity to the molecular mechanisms that consolidate changes in synaptic strength within specific neuronal circuits.
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Affiliation(s)
- S Finkbeiner
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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22
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Abstract
CREB is a transcription factor implicated in the control of adaptive neuronal responses. Although one function of CREB in neurons is believed to be the regulation of genes whose products control synaptic function, the targets of CREB that mediate synaptic function have not yet been identified. This report describes experiments demonstrating that CREB or a closely related protein mediates Ca2+-dependent regulation of BDNF, a neurotrophin that modulates synaptic activity. In cortical neurons, Ca2+ influx triggers phosphorylation of CREB, which by binding to a critical Ca2+ response element (CRE) within the BDNF gene activates BDNF transcription. Mutation of the BDNF CRE or an adjacent novel regulatory element as well as a blockade of CREB function resulted in a dramatic loss of BDNF transcription. These findings suggest that a CREB family member acts cooperatively with an additional transcription factor(s) to regulate BDNF transcription. We conclude that the BDNF gene is a CREB family target whose protein product functions at synapses to control adaptive neuronal responses.
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Affiliation(s)
- X Tao
- Children's Hospital, Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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23
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Abstract
Neurotrophins regulate neuronal survival, differentiation, and synaptic function. To understand how neurotrophins elicit such diverse responses, we elucidated signaling pathways by which brain-derived neurotrophic factor (BDNF) activates gene expression in cultured neurons and hippocampal slices. We found, unexpectedly, that the transcription factor cyclic AMP response element-binding protein (CREB) is an important regulator of BDNF-induced gene expression. Exposure of neurons to BDNF stimulates CREB phosphorylation and activation via at least two signaling pathways: by a calcium/calmodulin-dependent kinase IV (CaMKIV)-regulated pathway that is activated by the release of intracellular calcium and by a Ras-dependent pathway. These findings reveal a previously unrecognized, CaMK-dependent mechanism by which neurotrophins activate CREB and suggest that CREB plays a central role in mediating neurotrophin responses in neurons.
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Affiliation(s)
- S Finkbeiner
- Department of Neurology, Children's Hospital, Boston, Massachusetts 02115, USA
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24
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Abstract
A key characteristic of an animal's nervous system is that it can respond to brief environmental stimuli with lasting changes in its structure and function. These changes are triggered by specific patterns of neuronal electrical activity and are manifested as changes in the strength and patterns of synaptic connectivity between activated neurons. The biochemical mechanisms that control these changes are unclear, but cytoplasmic rises in Ca2+ levels may play a critical role, especially in regulating neuronal gene expression for making activity-induced synaptic changes permanent. Recently, two reports have explored the spatial features by which activity-induced rises in Ca2+ levels activate transcription factors and gene expression. The reports suggest that Ca2+ influx acts both locally at the synapse and distantly within the nucleus to regulate transcription factors and gene expression. The results also show that regulatory elements within genes can respond differentially, depending on spatial differences in intracellular Ca2+ rises. These reports suggest new spatial mechanisms by which Ca(2+)-dependent gene expression could contribute to activity-dependent synaptic changes.
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Affiliation(s)
- S Finkbeiner
- Department of Neurology, Children's Hospital, Boston, MA 02155, USA
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25
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Affiliation(s)
- S Finkbeiner
- Department of Neurobiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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26
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Rosenbauer M, Finkbeiner S, Bustarret E, Weber J, Stutzmann M. Resonantly excited photoluminescence spectra of porous silicon. Phys Rev B Condens Matter 1995; 51:10539-10547. [PMID: 9977748 DOI: 10.1103/physrevb.51.10539] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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27
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Abstract
Stimulus-evoked cellular responses are sometimes organized in the form of propagating waves of cytoplasmic Ca2+ increase. Ca2+ waves can be elicited in cultured astrocytes by the neurotransmitter glutamate; however, the propagation mechanism is unknown. Here, qualitative and quantitative features of propagation suggest that astrocytic Ca2+ waves are mediated by an intracellular signal that crosses intercellular junctions. The role of gap junctions in cell-cell Ca2+ wave propagation was specifically tested. Functional gap junctions were demonstrated using a noninvasive fluorescence recovery method and the gap junction blockers halothane and octanol. Gap junction closure prevented intracellular waves from propagating between cells without affecting the velocity of the intracellular wave itself. The pivotal role played by the gap junction creates the potential for dynamic changes in glial connectivity and long-range glial signaling.
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Affiliation(s)
- S Finkbeiner
- Section of Neurobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06511
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28
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Schick K, Daub E, Finkbeiner S, W�rfel P. Verification of a generalized Planck law for luminescence radiation from silicon solar cells. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/bf00323895] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Abstract
Ciprofloxacin, a quinolone antibiotic which exhibits minimal side effects and has broad antimicrobial spectrum, is being used frequently to treat various infections. A patient is reported who had previously maintained a stable prothrombin time on Coumadin for 5 years, and who exhibited a marked prolongation of prothrombin time when placed on ciprofloxacin for gastroenteritis.
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Affiliation(s)
- R Renzi
- Yale University School of Medicine, New Haven, CT
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30
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Keana JF, McBurney RN, Scherz MW, Fischer JB, Hamilton PN, Smith SM, Server AC, Finkbeiner S, Stevens CF, Jahr C. Synthesis and characterization of a series of diarylguanidines that are noncompetitive N-methyl-D-aspartate receptor antagonists with neuroprotective properties. Proc Natl Acad Sci U S A 1989; 86:5631-5. [PMID: 2546162 PMCID: PMC297678 DOI: 10.1073/pnas.86.14.5631] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Four diarylguanidine derivatives were synthesized. These compounds were found to displace, at submicromolar concentrations, 3H-labeled 1-[1-(2-thienyl)cyclohexyl]piperidine and (+)-[3H]MK-801 from phencyclidine receptors in brain membrane preparations. In electrophysiological experiments the diarylguanidines blocked N-methyl-D-aspartate (NMDA)-activated ion channels. These diarylguanidines also protected rat hippocampal neurons in vitro from glutamate-induced cell death. Our results show that some diarylguanidines are noncompetitive antagonists of NMDA receptor-mediated responses and have the neuroprotective property that is commonly associated with blockers of the NMDA receptor-gated cation channel. Diarylguanidines are structurally unrelated to known blockers of NMDA channels and, therefore, represent a new compound series for the development of neuroprotective agents with therapeutic value in patients suffering from stroke, from brain or spinal cord trauma, from hypoglycemia, and possibly from brain ischemia due to heart attack.
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Affiliation(s)
- J F Keana
- Department of Chemistry, University of Oregon, Eugene 97403
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31
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Abstract
The role of the N-methyl-D-aspartate receptor channel in glutamate neurotoxicity was investigated in cultured hippocampal neurons of the CA1 region. An equation, the survival function, was developed to quantify the effects of putative modulators of neurotoxicity. 2-Amino-5-phosphonovaleric acid (30 microM) reduced the neuronal sensitivity to glutamate by a factor greater than 20, whereas glycine (1 microM) enhanced it by a factor of 7.5 +/- 2.5. Neurons were protected by increasing Mg2+ concentrations in a predictable way based on the ion's ability to block the N-methyl-D-aspartate channel. These findings provide a quantitative basis for the assessment of various neuroprotective agents and add further support to the hypothesis that the N-methyl-D-aspartate channel is central to glutamate neurotoxicity.
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Affiliation(s)
- S Finkbeiner
- Section of Molecular Neurobiology, Yale University School of Medicine, New Haven, CT 06510
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