83
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Endoplasmic reticulum proteostasis impairment in aging

      review-article

      Read this article at

      ScienceOpenPublisherPMC
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Summary

          Perturbed neuronal proteostasis is a salient feature shared by both aging and protein misfolding disorders. The proteostasis network controls the health of the proteome by integrating pathways involved in protein synthesis, folding, trafficking, secretion, and their degradation. A reduction in the buffering capacity of the proteostasis network during aging may increase the risk to undergo neurodegeneration by enhancing the accumulation of misfolded proteins. As almost one‐third of the proteome is synthetized at the endoplasmic reticulum ( ER), maintenance of its proper function is fundamental to sustain neuronal function. In fact, ER stress is a common feature of most neurodegenerative diseases. The unfolded protein response ( UPR) operates as central player to maintain ER homeostasis or the induction of cell death of chronically damaged cells. Here, we discuss recent evidence placing ER stress as a driver of brain aging, and the emerging impact of neuronal UPR in controlling global proteostasis at the whole organismal level. Finally, we discuss possible therapeutic interventions to improve proteostasis and prevent pathological brain aging.

          Related collections

          Most cited references89

          • Record: found
          • Abstract: found
          • Article: not found

          Transcriptional induction of mammalian ER quality control proteins is mediated by single or combined action of ATF6alpha and XBP1.

          Metazoans express three unfolded protein response transducers (IRE1, PERK, and ATF6) ubiquitously to cope with endoplasmic reticulum (ER) stress. ATF6 is an ER membrane-bound transcription factor activated by ER stress-induced proteolysis and has been duplicated in mammals. Here, we generated ATF6alpha- and ATF6beta-knockout mice, which developed normally, and then found that their double knockout caused embryonic lethality. Analysis of mouse embryonic fibroblasts (MEFs) deficient in ATF6alpha or ATF6beta revealed that ATF6alpha is solely responsible for transcriptional induction of ER chaperones and that ATF6alpha heterodimerizes with XBP1 for the induction of ER-associated degradation components. ATF6alpha(-/-) MEFs are sensitive to ER stress. Unaltered responses observed in ATF6beta(-/-) MEFs indicate that ATF6beta is not a negative regulator of ATF6alpha. These results demonstrate that ATF6alpha functions as a critical regulator of ER quality control proteins in mammalian cells, in marked contrast to worm and fly cells in which IRE1 is responsible.
            • Record: found
            • Abstract: found
            • Article: not found

            Collapse of proteostasis represents an early molecular event in Caenorhabditis elegans aging.

            Protein damage contributes prominently to cellular aging. To address whether this occurs at a specific period during aging or accumulates gradually, we monitored the biochemical, cellular, and physiological properties of folding sensors expressed in different tissues of C. elegans. We observed the age-dependent misfolding and loss of function of diverse proteins harboring temperature-sensitive missense mutations in all somatic tissues at the permissive condition. This widespread failure in proteostasis occurs rapidly at an early stage of adulthood, and coincides with a severely reduced activation of the cytoprotective heat shock response and the unfolded protein response. Enhancing stress responsive factors HSF-1 or DAF-16 suppresses misfolding of these metastable folding sensors and restores the ability of the cell to maintain a functional proteome. This suggests that a compromise in the regulation of proteostatic stress responses occurs early in adulthood and tips the balance between the load of damaged proteins and the proteostasis machinery. We propose that the collapse of proteostasis represents an early molecular event of aging that amplifies protein damage in age-associated diseases of protein conformation.
              • Record: found
              • Abstract: found
              • Article: not found

              Sustained translational repression by eIF2α-P mediates prion neurodegeneration.

              The mechanisms leading to neuronal death in neurodegenerative disease are poorly understood. Many of these disorders, including Alzheimer's, Parkinson's and prion diseases, are associated with the accumulation of misfolded disease-specific proteins. The unfolded protein response is a protective cellular mechanism triggered by rising levels of misfolded proteins. One arm of this pathway results in the transient shutdown of protein translation, through phosphorylation of the α-subunit of eukaryotic translation initiation factor, eIF2. Activation of the unfolded protein response and/or increased eIF2α-P levels are seen in patients with Alzheimer's, Parkinson's and prion diseases, but how this links to neurodegeneration is unknown. Here we show that accumulation of prion protein during prion replication causes persistent translational repression of global protein synthesis by eIF2α-P, associated with synaptic failure and neuronal loss in prion-diseased mice. Further, we show that promoting translational recovery in hippocampi of prion-infected mice is neuroprotective. Overexpression of GADD34, a specific eIF2α-P phosphatase, as well as reduction of levels of prion protein by lentivirally mediated RNA interference, reduced eIF2α-P levels. As a result, both approaches restored vital translation rates during prion disease, rescuing synaptic deficits and neuronal loss, thereby significantly increasing survival. In contrast, salubrinal, an inhibitor of eIF2α-P dephosphorylation, increased eIF2α-P levels, exacerbating neurotoxicity and significantly reducing survival in prion-diseased mice. Given the prevalence of protein misfolding and activation of the unfolded protein response in several neurodegenerative diseases, our results suggest that manipulation of common pathways such as translational control, rather than disease-specific approaches, may lead to new therapies preventing synaptic failure and neuronal loss across the spectrum of these disorders.

                Author and article information

                Contributors
                chetz@hsph.harvard.edu
                Journal
                Aging Cell
                Aging Cell
                10.1111/(ISSN)1474-9726
                ACEL
                Aging Cell
                John Wiley and Sons Inc. (Hoboken )
                1474-9718
                1474-9726
                23 April 2017
                August 2017
                : 16
                : 4 ( doiID: 10.1111/acel.2017.16.issue-4 )
                : 615-623
                Affiliations
                [ 1 ] Center for Geroscience, Brain Health and Metabolism Santiago Chile
                [ 2 ] Biomedical Neuroscience Institute Faculty of Medicine University of Chile Santiago Chile
                [ 3 ] Program of Cellular and Molecular Biology Institute of Biomedical Sciences University of Chile Santiago Chile
                [ 4 ] Center for Integrative Biology Universidad Mayor Santiago Chile
                [ 5 ] Instituto de Ciências Biomédicas Universidade Federal do Rio de Janeiro Rio de Janeiro Brasil
                [ 6 ] Buck Institute for Research on Aging Novato CA 94945 USA
                [ 7 ] Department of Immunology and Infectious diseases Harvard School of Public Health Boston MA 02115 USA
                Author notes
                [*] [* ] Correspondence

                Claudio Hetz, Institute of Biomedical Sciences, University of Chile, Independencia 1027, Santiago, Chile. Tel.: 56 2 2978 6506; e‐mails:   chetz@ 123456hsph.harvard.edu

                Article
                ACEL12599
                10.1111/acel.12599
                5506418
                28436203
                80addc0c-d08b-4ae8-b07b-fea2e03421c0
                © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

                This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

                History
                : 15 March 2017
                Page count
                Figures: 2, Tables: 2, Pages: 9, Words: 9499
                Funding
                Funded by: FONDAP program
                Award ID: 15150012
                Funded by: US Office of Naval Research‐Global (ONR‐G)
                Award ID: N62909‐16‐1‐2003
                Funded by: Millennium Institute
                Award ID: P09‐015‐F
                Award ID: ID16I10223
                Award ID: D11E1007
                Funded by: FONDEF
                Funded by: U.S. Air Force Office of Scientific Research
                Award ID: FA9550‐16‐1‐0384
                Funded by: CONICYT‐Brazil
                Award ID: 441921/2016‐7
                Funded by: FONDECYT
                Award ID: 11160760
                Award ID: 3150637
                Award ID: 1140549
                Funded by: ALS Therapy Alliance
                Award ID: 2014‐F‐059
                Funded by: Muscular Dystrophy Association
                Award ID: 382453
                Funded by: Michael J Fox Foundation for Parkinson's Research—Target Validation
                Award ID: 9277
                Categories
                Review
                Reviews
                Custom metadata
                2.0
                acel12599
                August 2017
                Converter:WILEY_ML3GV2_TO_NLMPMC version:5.1.4 mode:remove_FC converted:21.07.2017

                Cell biology
                aging,endoplasmic reticulum,endoplasmic reticulum stress,protein misfolding disorders,unfolded protein response

                Comments

                Comment on this article

                Related Documents Log