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Ugalde MV, Alecki C, Rizwan J, Le P, Jacob-Tomas S, Xu JM, Minotti S, Wu T, Durham H, Yeo G. Localized molecular chaperone synthesis maintains neuronal dendrite proteostasis. RESEARCH SQUARE 2023:rs.3.rs-3673702. [PMID: 38168440 PMCID: PMC10760236 DOI: 10.21203/rs.3.rs-3673702/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. However, this is challenging in neuronal projections because of their polarized morphology and constant synaptic proteome remodeling. Using high-resolution fluorescence microscopy, we discovered that neurons localize a subset of chaperone mRNAs to their dendrites and use microtubule-based transport to increase this asymmetric localization following proteotoxic stress. The most abundant dendritic chaperone mRNA encodes a constitutive heat shock protein 70 family member (HSPA8). Proteotoxic stress also enhanced HSPA8 mRNA translation efficiency in dendrites. Stress-mediated HSPA8 mRNA localization to the dendrites was impaired by depleting fused in sarcoma-an amyotrophic lateral sclerosis-related protein-in cultured mouse motor neurons and expressing a pathogenic variant of heterogenous nuclear ribonucleoprotein A2/B1 in neurons derived from human induced pluripotent stem cells. These results reveal a crucial and unexpected neuronal stress response in which RNA-binding proteins increase the dendritic localization of HSPA8 mRNA to maintain proteostasis and prevent neurodegeneration.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gene Yeo
- University of California, San Diego
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Alecki C, Rizwan J, Le P, Jacob-Tomas S, Xu S, Minotti S, Wu T, Durham H, Yeo GW, Vera M. Localized synthesis of molecular chaperones sustains neuronal proteostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.03.560761. [PMID: 37873158 PMCID: PMC10592939 DOI: 10.1101/2023.10.03.560761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Neurons are challenged to maintain proteostasis in neuronal projections, particularly with the physiological stress at synapses to support intercellular communication underlying important functions such as memory and movement control. Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. Using high-resolution fluorescent microscopy, we discovered that neurons localize a subset of chaperone mRNAs to their dendrites, particularly more proximal regions, and increase this asymmetric localization following proteotoxic stress through microtubule-based transport from the soma. The most abundant chaperone mRNA in dendrites encodes the constitutive heat shock protein 70, HSPA8. Proteotoxic stress in cultured neurons, induced by inhibiting proteasome activity or inducing oxidative stress, enhanced transport of Hspa8 mRNAs to dendrites and the percentage of mRNAs engaged in translation on mono and polyribosomes. Knocking down the ALS-related protein Fused in Sarcoma (FUS) and a dominant mutation in the heterogenous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1) impaired stress-mediated localization of Hspa8 mRNA to dendrites in cultured murine motor neurons and human iPSC-derived neurons, respectively, revealing the importance of these RNA-binding proteins in maintaining proteostasis. These results reveal the increased dendritic localization and translation of the constitutive HSP70 Hspa8 mRNA as a crucial neuronal stress response to uphold proteostasis and prevent neurodegeneration.
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Affiliation(s)
- Celia Alecki
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Javeria Rizwan
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Phuong Le
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Suleima Jacob-Tomas
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Stella Xu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Sandra Minotti
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Tad Wu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Heather Durham
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Maria Vera
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Alagar Boopathy LR, Jacob-Tomas S, Alecki C, Vera M. Mechanisms tailoring the expression of heat shock proteins to proteostasis challenges. J Biol Chem 2022; 298:101796. [PMID: 35248532 PMCID: PMC9065632 DOI: 10.1016/j.jbc.2022.101796] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 12/14/2022] Open
Abstract
All cells possess an internal stress response to cope with environmental and pathophysiological challenges. Upon stress, cells reprogram their molecular functions to activate a survival mechanism known as the heat shock response, which mediates the rapid induction of molecular chaperones such as the heat shock proteins (HSPs). This potent production overcomes the general suppression of gene expression and results in high levels of HSPs to subsequently refold or degrade misfolded proteins. Once the damage or stress is repaired or removed, cells terminate the production of HSPs and resume regular functions. Thus, fulfillment of the stress response requires swift and robust coordination between stress response activation and completion that is determined by the status of the cell. In recent years, single-cell fluorescence microscopy techniques have begun to be used in unravelling HSP-gene expression pathways, from DNA transcription to mRNA degradation. In this review, we will address the molecular mechanisms in different organisms and cell types that coordinate the expression of HSPs with signaling networks that act to reprogram gene transcription, mRNA translation, and decay and ensure protein quality control.
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Abstract
Anisometropic amblyopia is unilateral by definition and current treatment recommendations reflect that characteristic. However, recent research suggests a binocular component that deserves consideration. The aim of this review is to consider the levels of anisometropia deemed amblyogenic, and the cortical changes that occur in the presence of anisometropic amblyopia. Particular attention is given to cortical changes that impact the binocularity of these individuals. Knowledge of binocular deficits in anisometropic amblyopia has implications for current, accepted treatment regimens which are monocular in nature. Therefore, the integrity of binocular function in anisometropic amblyopia and its impact on the visual outcome will be evaluated. Given the rise in binocular treatments under clinical trial for amblyopia, this review also aims to evaluate the evidence of potentially enhanced benefits to anisometropic amblyopes from proposed new binocular therapies.
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Affiliation(s)
| | - Charlotte J Codina
- Academic Unit of Ophthalmology and Orthoptics, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, UK
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Olsen LA, Nicoll JX, Fry AC. The skeletal muscle fiber: a mechanically sensitive cell. Eur J Appl Physiol 2019; 119:333-349. [PMID: 30612167 DOI: 10.1007/s00421-018-04061-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022]
Abstract
The plasticity of skeletal muscle, whether an increase in size, change in metabolism, or alteration in structural properties, is in a continuous state of flux largely dependent upon physical activity. Much of the past research has expounded upon these ever-changing aspects of the muscle fiber following exercise. Specifically, endocrine and paracrine signaling have been heavily investigated lending to much of the past literature comprised of such endocrinological dynamics following muscle activity. Mechanotransduction, the ability of a cell to convert a mechanical stimulus into an intracellular biochemical response, has garnered much less attention. Recent work, however, has demonstrated the physical continuity of the muscle fiber, specifically demonstrating a continuous physical link between the extracellular matrix (ECM), cytoskeleton, and nuclear matrix as a means to rapidly regulate gene expression following a mechanical stimulus. Similarly, research has shown mechanical stimuli to directly influence cytoplasmic signaling whether through oxidative adaptations, increased muscle size, or enhanced muscle integrity. Regrettably, minimal research has investigated the role that exercise may play within the mechanotransducing signaling cascades. This proposed line of study may prove paramount as muscle-related diseases greatly impact one's ability to lead an independent lifestyle along with contributing a substantial burden upon the economy. Thus, this review explores both biophysical and biochemical mechanotransduction, and how these signaling pathways may be influenced following exercise.
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Affiliation(s)
- Luke A Olsen
- Biomedical Sciences, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Justin X Nicoll
- Department of Kinesiology, California State University, Northridge, CA, 91330-8287, USA
| | - Andrew C Fry
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS, 66045, USA.
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Maass PG, Barutcu AR, Rinn JL. Interchromosomal interactions: A genomic love story of kissing chromosomes. J Cell Biol 2018; 218:27-38. [PMID: 30181316 PMCID: PMC6314556 DOI: 10.1083/jcb.201806052] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/27/2018] [Accepted: 08/01/2018] [Indexed: 01/26/2023] Open
Abstract
Maass et al. review interchromosomal interactions, which, like intrachromosomal interactions, are emerging as important regulators of genome organization and gene expression. Nuclei require a precise three- and four-dimensional organization of DNA to establish cell-specific gene-expression programs. Underscoring the importance of DNA topology, alterations to the nuclear architecture can perturb gene expression and result in disease states. More recently, it has become clear that not only intrachromosomal interactions, but also interchromosomal interactions, a less studied feature of chromosomes, are required for proper physiological gene-expression programs. Here, we review recent studies with emerging insights into where and why cross-chromosomal communication is relevant. Specifically, we discuss how long noncoding RNAs (lncRNAs) and three-dimensional gene positioning are involved in genome organization and how low-throughput (live-cell imaging) and high-throughput (Hi-C and SPRITE) techniques contribute to understand the fundamental properties of interchromosomal interactions.
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Affiliation(s)
- Philipp G Maass
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA
| | - A Rasim Barutcu
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - John L Rinn
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA .,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA.,Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA.,University of Colorado, BioFrontiers, Department of Biochemistry, Boulder, CO
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