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Nam KH, Ordureau A. How does the neuronal proteostasis network react to cellular cues? Biochem Soc Trans 2024; 52:581-592. [PMID: 38488108 DOI: 10.1042/bst20230316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/25/2024]
Abstract
Even though neurons are post-mitotic cells, they still engage in protein synthesis to uphold their cellular content balance, including for organelles, such as the endoplasmic reticulum or mitochondria. Additionally, they expend significant energy on tasks like neurotransmitter production and maintaining redox homeostasis. This cellular homeostasis is upheld through a delicate interplay between mRNA transcription-translation and protein degradative pathways, such as autophagy and proteasome degradation. When faced with cues such as nutrient stress, neurons must adapt by altering their proteome to survive. However, in many neurodegenerative disorders, such as Parkinson's disease, the pathway and processes for coping with cellular stress are impaired. This review explores neuronal proteome adaptation in response to cellular stress, such as nutrient stress, with a focus on proteins associated with autophagy, stress response pathways, and neurotransmitters.
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Affiliation(s)
- Ki Hong Nam
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
| | - Alban Ordureau
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, U.S.A
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2
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Pragati, Sarkar S. Reinstated Activity of Human Tau-induced Enhanced Insulin Signaling Restricts Disease Pathogenesis by Regulating the Functioning of Kinases/Phosphatases and Tau Hyperphosphorylation in Drosophila. Mol Neurobiol 2024; 61:982-1001. [PMID: 37674037 DOI: 10.1007/s12035-023-03599-y] [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: 04/04/2023] [Accepted: 08/18/2023] [Indexed: 09/08/2023]
Abstract
Tauopathies such as Alzheimer's disease (AD), Frontotemporal dementia, and parkinsonism linked to chromosome 17 (FTDP-17), etc. are characterized by tau hyperphosphorylation and distinguished accumulation of paired helical filaments (PHFs)/or neurofibrillary tangles (NFTs) in a specific-neuronal subset of the brain. Among different reported risk factors, type 2 diabetes (T2D) has gained attention due to its correlation with tau pathogenesis. However, mechanistic details and the precise contribution of insulin pathway in tau etiology is still debatable. We demonstrate that expression of human tau causes overactivation of insulin pathway in Drosophila disease models. We subsequently noted that tissue-specific downregulation of insulin signaling or even exclusive reduction of its growth-promoting sub-branch effectively reinstates the overactivated insulin signaling pathway in human tau expressing cells, which in turn restricts pathogenic tau hyperphosphorylation and aggregate formation. It was further noted that restored tau phosphorylation was achieved due to a reestablished balance between the levels of different kinase(s) (GSK3β and ERK/P38 MAP kinase) and phosphatase (PP2A). Taken together, our study demonstrates a precise involvement of the insulin pathway and associated molecular events in the pathogenesis of human tauopathies in Drosophila, which will be immensely helpful in developing novel therapeutic options against these devastating human brain disorders. Moreover, our study reveals an interesting link between tau etiology and aberrant insulin signaling, which is a characteristic feature of Type 2 Diabetes.
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Affiliation(s)
- Pragati
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Surajit Sarkar
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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3
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Sung H, Lloyd TE. Disrupted endoplasmic reticulum-mediated autophagosomal biogenesis in a Drosophila model of C9-ALS-FTD. Autophagy 2024; 20:94-113. [PMID: 37599467 PMCID: PMC10761023 DOI: 10.1080/15548627.2023.2249750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/22/2023] Open
Abstract
ABBREVIATIONS 3R: UAS construct expressing 3 G4C2 repeats (used as control); 3WJ: three-way junction; 12R: UAS construct expressing leader sequence and 12 G4C2 repeats; 30R: UAS construct expressing 30 G4C2 repeats; 36R: UAS construct expressing 36 G4C2 repeats; 44R: UAS construct expressing leader sequence and 44 G4C2 repeats; ALS: amyotrophic lateral sclerosis; Atg: autophagy related; atl: atlastin; C9-ALS-FTD: ALS or FTD caused by hexanuleotide repeat expansion in C9orf72; ER: endoplasmic reticulum; FTD: frontotemporal dementia; HRE: GGGGCC hexanucleotide repeat expansion; HSP: hereditary spastic paraplegia; Lamp1: lysosomal associated membrane protein 1; MT: microtubule; NMJ: neuromuscular junction; Rab: Ras-associated binding GTPase; RAN: repeat associated non-AUG (RAN) translation; RO-36: UAS construct expression "RNA-only" version of 36 G4C2 repeats in which stop codons in all six reading frames are inserted.; Rtnl1: Reticulon-like 1; SN: segmental nerve; TFEB/Mitf: transcription factor EB/microphthalmia associated transcription factor (Drosophila ortholog of TFEB); TrpA1: transient receptor potential cation channel A1; VAPB: VAMP associated protein B and C; VNC: ventral nerve cord (spinal cord in Drosophila larvae).
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Affiliation(s)
- Hyun Sung
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Thomas E. Lloyd
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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4
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Ben-Zvi H, Rabinski T, Ofir R, Cohen S, Vatine GD. PLEKHM2 Loss of Function Impairs the Activity of iPSC-Derived Neurons via Regulation of Autophagic Flux. Int J Mol Sci 2022; 23:ijms232416092. [PMID: 36555735 PMCID: PMC9782635 DOI: 10.3390/ijms232416092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Pleckstrin Homology And RUN Domain Containing M2 (PLEKHM2) [delAG] mutation causes dilated cardiomyopathy with left ventricular non-compaction (DCM-LVNC), resulting in a premature death of PLEKHM2[delAG] individuals due to heart failure. PLEKHM2 is a factor involved in autophagy, a master regulator of cellular homeostasis, decomposing pathogens, proteins and other cellular components. Autophagy is mainly carried out by the lysosome, containing degradation enzymes, and by the autophagosome, which engulfs substances marked for decomposition. PLEKHM2 promotes lysosomal movement toward the cell periphery. Autophagic dysregulation is associated with neurodegenerative diseases' pathogenesis. Thus, modulation of autophagy holds considerable potential as a therapeutic target for such disorders. We hypothesized that PLEKHM2 is involved in neuronal development and function, and that mutated PLEKHM2 (PLEKHM2[delAG]) neurons will present impaired functions. Here, we studied PLEKHM2-related abnormalities in induced pluripotent stem cell (iPSC)-derived motor neurons (iMNs) as a neuronal model. PLEKHM2[delAG] iMN cultures had healthy control-like differentiation potential but exhibited reduced autophagic activity. Electrophysiological measurements revealed that PLEKHM2[delAG] iMN cultures displayed delayed functional maturation and more frequent and unsynchronized activity. This was associated with increased size and a more perinuclear lysosome cellular distribution. Thus, our results suggest that PLEKHM2 is involved in the functional development of neurons through the regulation of autophagic flux.
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Affiliation(s)
- Hadas Ben-Zvi
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Tatiana Rabinski
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Rivka Ofir
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Dead Sea & Arava Science Center, Masada 8691000, Israel
| | - Smadar Cohen
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Correspondence: (S.C.); (G.D.V.)
| | - Gad D. Vatine
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- The Zelman School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Correspondence: (S.C.); (G.D.V.)
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5
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Inhibition of mTOR improves malnutrition induced hepatic metabolic dysfunction. Sci Rep 2022; 12:19948. [PMID: 36402829 PMCID: PMC9675758 DOI: 10.1038/s41598-022-24428-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/15/2022] [Indexed: 11/21/2022] Open
Abstract
Severe malnutrition accounts for half-a-million deaths annually in children under the age of five. Despite improved WHO guidelines, inpatient mortality remains high and is associated with metabolic dysfunction. Previous studies suggest a correlation between hepatic metabolic dysfunction and impaired autophagy. We aimed to determine the role of mTORC1 inhibition in a murine model of malnutrition-induced hepatic dysfunction. Wild type weanling C57/B6 mice were fed a 18 or 1% protein diet for two weeks. A third low-protein group received daily rapamycin injections, an mTORC1 inhibitor. Hepatic metabolic function was assessed by histology, immunofluorescence, gene expression, metabolomics and protein levels. Low protein-fed mice manifested characteristics of severe malnutrition, including weight loss, hypoalbuminemia, hypoglycemia, hepatic steatosis and cholestasis. Low protein-fed mice had fewer mitochondria and showed signs of impaired mitochondrial function. Rapamycin prevented hepatic steatosis, restored ATP levels and fasted plasma glucose levels compared to untreated mice. This correlated with increased content of LC3-II, and decreased content mitochondrial damage marker, PINK1. We demonstrate that hepatic steatosis and disturbed mitochondrial function in a murine model of severe malnutrition can be partially prevented through inhibition of mTORC1. These findings suggest that stimulation of autophagy could be a novel approach to improve metabolic function in severely malnourished children.
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Overhoff M, Tellkamp F, Hess S, Tolve M, Tutas J, Faerfers M, Ickert L, Mohammadi M, De Bruyckere E, Kallergi E, Delle Vedove A, Nikoletopoulou V, Wirth B, Isensee J, Hucho T, Puchkov D, Isbrandt D, Krueger M, Kloppenburg P, Kononenko NL. Autophagy regulates neuronal excitability by controlling cAMP/protein kinase A signaling at the synapse. EMBO J 2022; 41:e110963. [PMID: 36217825 PMCID: PMC9670194 DOI: 10.15252/embj.2022110963] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 09/10/2022] [Accepted: 09/14/2022] [Indexed: 01/13/2023] Open
Abstract
Autophagy provides nutrients during starvation and eliminates detrimental cellular components. However, accumulating evidence indicates that autophagy is not merely a housekeeping process. Here, by combining mouse models of neuron-specific ATG5 deficiency in either excitatory or inhibitory neurons with quantitative proteomics, high-content microscopy, and live-imaging approaches, we show that autophagy protein ATG5 functions in neurons to regulate cAMP-dependent protein kinase A (PKA)-mediated phosphorylation of a synapse-confined proteome. This function of ATG5 is independent of bulk turnover of synaptic proteins and requires the targeting of PKA inhibitory R1 subunits to autophagosomes. Neuronal loss of ATG5 causes synaptic accumulation of PKA-R1, which sequesters the PKA catalytic subunit and diminishes cAMP/PKA-dependent phosphorylation of postsynaptic cytoskeletal proteins that mediate AMPAR trafficking. Furthermore, ATG5 deletion in glutamatergic neurons augments AMPAR-dependent excitatory neurotransmission and causes the appearance of spontaneous recurrent seizures in mice. Our findings identify a novel role of autophagy in regulating PKA signaling at glutamatergic synapses and suggest the PKA as a target for restoration of synaptic function in neurodegenerative conditions with autophagy dysfunction.
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Affiliation(s)
- Melina Overhoff
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Frederik Tellkamp
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany
| | - Simon Hess
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of ZoologyUniversity of CologneCologneGermany
| | - Marianna Tolve
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Janine Tutas
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Marcel Faerfers
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Lotte Ickert
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Milad Mohammadi
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Elodie De Bruyckere
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Emmanouela Kallergi
- Département des Neurosciences FondamentalesUniversity of LausanneLausanneSwitzerland
| | - Andrea Delle Vedove
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | | | - Brunhilde Wirth
- Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany,Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Joerg Isensee
- Translational Pain Research, Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Tim Hucho
- Translational Pain Research, Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Dmytro Puchkov
- Leibniz Institute for Molecular Pharmacology (FMP)BerlinGermany
| | - Dirk Isbrandt
- Institute for Molecular and Behavioral Neuroscience, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany,Experimental NeurophysiologyGerman Center for Neurodegenerative DiseasesBonnGermany
| | - Marcus Krueger
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany
| | - Peter Kloppenburg
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of ZoologyUniversity of CologneCologneGermany
| | - Natalia L Kononenko
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
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7
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Neuronal-specific septin-3 binds Atg8/LC3B, accumulates and localizes to autophagosomes during induced autophagy. Cell Mol Life Sci 2022; 79:471. [PMID: 35932293 PMCID: PMC9356936 DOI: 10.1007/s00018-022-04488-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/27/2022] [Accepted: 07/13/2022] [Indexed: 11/03/2022]
Abstract
In synapses that show signs of local apoptosis and mitochondrial stress and undergo neuro-immunological synapse pruning, an increase in the levels of the presynaptic protein, neuronal-specific septin-3 can be observed. Septin-3 is a member of the septin GTPase family with the ability to form multimers and contribute to the cytoskeleton. However, the function of septin-3 remains elusive. Here, we provide evidence that septin-3 is capable of binding the most-studied autophagy protein Atg8 homolog microtubule-associated protein 1 light chain 3B (LC3B), besides another homolog, GABA receptor-associated protein-like 2 (GABARAPL2). Moreover, we demonstrate that colocalization of septin-3 and LC3B increases upon chemical autophagy induction in primary neuronal cells. Septin-3 is accumulated in primary neurons upon autophagy enhancement or blockade, similar to autophagy proteins. Using electron microscopy, we also show that septin-3 localizes to LC3B positive membranes and can be found at mitochondria. However, colocalization results of septin-3 and the early mitophagy marker PTEN-induced kinase 1 (PINK1) do not support that binding of septin-3 to mitochondria is mitophagy related. We conclude that septin-3 correlates with synaptic/neuronal autophagy, binds Atg8 and localizes to autophagic membranes that can be enhanced with chemical autophagy induction. Based on our results, elevated septin-3 levels might indicate enhanced or impeded autophagy in neurons.
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8
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Griffey CJ, Yamamoto A. Macroautophagy in CNS health and disease. Nat Rev Neurosci 2022; 23:411-427. [PMID: 35505254 DOI: 10.1038/s41583-022-00588-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2022] [Indexed: 12/12/2022]
Abstract
Macroautophagy is an evolutionarily conserved process that delivers diverse cellular contents to lysosomes for degradation. As our understanding of this pathway grows, so does our appreciation for its importance in disorders of the CNS. Once implicated primarily in neurodegenerative events owing to acute injury and ageing, macroautophagy is now also linked to disorders of neurodevelopment, indicating that it is essential for both the formation and maintenance of a healthy CNS. In parallel to understanding the significance of macroautophagy across contexts, we have gained a greater mechanistic insight into its physiological regulation and the breadth of cargoes it can degrade. Macroautophagy is a broadly used homeostatic process, giving rise to questions surrounding how defects in this single pathway could cause diseases with distinct clinical and pathological signatures. To address this complexity, we herein review macroautophagy in the mammalian CNS by examining three key features of the process and its relationship to disease: how it functions at a basal level in the discrete cell types of the brain and spinal cord; which cargoes are being degraded in physiological and pathological settings; and how the different stages of the macroautophagy pathway intersect with diseases of neurodevelopment and adult-onset neurodegeneration.
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Affiliation(s)
- Christopher J Griffey
- Doctoral Program in Neurobiology and Behaviour, Medical Scientist Training Program, Columbia University, New York, NY, USA
| | - Ai Yamamoto
- Departments of Neurology, and Pathology and Cell Biology, Columbia University, New York, NY, USA.
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9
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Gundelfinger ED, Karpova A, Pielot R, Garner CC, Kreutz MR. Organization of Presynaptic Autophagy-Related Processes. Front Synaptic Neurosci 2022; 14:829354. [PMID: 35368245 PMCID: PMC8968026 DOI: 10.3389/fnsyn.2022.829354] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Brain synapses pose special challenges on the quality control of their protein machineries as they are far away from the neuronal soma, display a high potential for plastic adaptation and have a high energy demand to fulfill their physiological tasks. This applies in particular to the presynaptic part where neurotransmitter is released from synaptic vesicles, which in turn have to be recycled and refilled in a complex membrane trafficking cycle. Pathways to remove outdated and damaged proteins include the ubiquitin-proteasome system acting in the cytoplasm as well as membrane-associated endolysosomal and the autophagy systems. Here we focus on the latter systems and review what is known about the spatial organization of autophagy and endolysomal processes within the presynapse. We provide an inventory of which components of these degradative systems were found to be present in presynaptic boutons and where they might be anchored to the presynaptic apparatus. We identify three presynaptic structures reported to interact with known constituents of membrane-based protein-degradation pathways and therefore may serve as docking stations. These are (i) scaffolding proteins of the cytomatrix at the active zone, such as Bassoon or Clarinet, (ii) the endocytic machinery localized mainly at the peri-active zone, and (iii) synaptic vesicles. Finally, we sketch scenarios, how presynaptic autophagic cargos are tagged and recruited and which cellular mechanisms may govern membrane-associated protein turnover in the presynapse.
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Affiliation(s)
- Eckart D. Gundelfinger
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- *Correspondence: Eckart D. Gundelfinger,
| | - Anna Karpova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Rainer Pielot
- Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Craig C. Garner
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Michael R. Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Center for Molecular Neurobiology (ZMNH), University Hospital Hamburg-Eppendorf, Hamburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
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10
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Tavčar Verdev P, Potokar M, Korva M, Resman Rus K, Kolenc M, Avšič Županc T, Zorec R, Jorgačevski J. In human astrocytes neurotropic flaviviruses increase autophagy, yet their replication is autophagy-independent. Cell Mol Life Sci 2022; 79:566. [PMID: 36283999 PMCID: PMC9596533 DOI: 10.1007/s00018-022-04578-7] [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: 07/07/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 01/18/2023]
Abstract
Astrocytes, an abundant type of glial cells, are the key cells providing homeostasis in the central nervous system. Due to their susceptibility to infection, combined with high resilience to virus-induced cell death, astrocytes are now considered one of the principal types of cells, responsible for virus retention and dissemination within the brain. Autophagy plays an important role in elimination of intracellular components and in maintaining cellular homeostasis and is also intertwined with the life cycle of viruses. The physiological significance of autophagy in astrocytes, in connection with the life cycle and transmission of viruses, remains poorly investigated. In the present study, we investigated flavivirus-induced modulation of autophagy in human astrocytes by monitoring a tandem fluorescent-tagged LC3 probe (mRFP-EGFP-LC3) with confocal and super-resolution fluorescence microscopy. Astrocytes were infected with tick-borne encephalitis virus (TBEV) or West Nile virus (WNV), both pathogenic flaviviruses, and with mosquito-only flavivirus (MOF), which is considered non-pathogenic. The results revealed that human astrocytes are susceptible to infection with TBEV, WNV and to a much lower extent also to MOF. Infection and replication rates of TBEV and WNV are paralleled by increased rate of autophagy, whereas autophagosome maturation and the size of autophagic compartments are not affected. Modulation of autophagy by rapamycin and wortmannin does not influence TBEV and WNV replication rate, whereas bafilomycin A1 attenuates their replication and infectivity. In human astrocytes infected with MOF, the low infectivity and the lack of efficient replication of this flavivirus are mirrored by the absence of an autophagic response.
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Affiliation(s)
- Petra Tavčar Verdev
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Potokar
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
| | - Miša Korva
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katarina Resman Rus
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Kolenc
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tatjana Avšič Županc
- grid.8954.00000 0001 0721 6013Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
| | - Jernej Jorgačevski
- grid.8954.00000 0001 0721 6013Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia ,grid.433223.7Celica Biomedical, Ljubljana, Slovenia
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11
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Decet M, Verstreken P. Presynaptic Autophagy and the Connection With Neurotransmission. Front Cell Dev Biol 2021; 9:790721. [PMID: 34988081 PMCID: PMC8722708 DOI: 10.3389/fcell.2021.790721] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/01/2021] [Indexed: 01/14/2023] Open
Abstract
Autophagy is an evolutionary conserved catabolic pathway essential for the maintenance of cellular homeostasis. Defective proteins and organelles are engulfed by autophagosomal membranes which fuse with lysosomes for cargo degradation. In neurons, the orchestrated progression of autophagosome formation and maturation occurs in distinct subcellular compartments. For synapses, the distance from the soma and the oxidative stress generated during intense neuronal activity pose a challenge to maintain protein homeostasis. Autophagy constitutes a crucial mechanism for proper functioning of this unique and vulnerable cellular compartment. We are now beginning to understand how autophagy is regulated at pre-synaptic terminals and how this pathway, when imbalanced, impacts on synaptic function and -ultimately- neuronal survival. We review here the current state of the art of "synaptic autophagy", with an emphasis on the biogenesis of autophagosomes at the pre-synaptic compartment. We provide an overview of the existing knowledge on the signals inducing autophagy at synapses, highlight the interplay between autophagy and neurotransmission, and provide perspectives for future research.
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Affiliation(s)
- Marianna Decet
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Mission Lucidity, Leuven, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Mission Lucidity, Leuven, Belgium
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12
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Zaccaria A, Antinori P, Licker V, Kövari E, Lobrinus JA, Burkhard PR. Multiomic Analyses of Dopaminergic Neurons Isolated from Human Substantia Nigra in Parkinson's Disease: A Descriptive and Exploratory Study. Cell Mol Neurobiol 2021; 42:2805-2818. [PMID: 34528139 PMCID: PMC9561004 DOI: 10.1007/s10571-021-01146-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/02/2021] [Indexed: 11/21/2022]
Abstract
Dopaminergic neurons (DA) of the substantia nigra pars compacta (SNpc) selectively and progressively degenerate in Parkinson’s disease (PD). Until now, molecular analyses of DA in PD have been limited to genomic or transcriptomic approaches, whereas, to the best of our knowledge, no proteomic or combined multiomic study examining the protein profile of these neurons is currently available. In this exploratory study, we used laser capture microdissection to extract regions from DA in 10 human SNpc obtained at autopsy in PD patients and control subjects. Extracted RNA and proteins were identified by RNA sequencing and nanoliquid chromatography–mass spectrometry, respectively, and the differential expression between PD and control group was assessed. Qualitative analyses confirmed that the microdissection protocol preserves the integrity of our samples and offers access to specific molecular pathways. This multiomic analysis highlighted differential expression of 52 genes and 33 proteins, including molecules of interest already known to be dysregulated in PD, such as LRP2, PNMT, CXCR4, MAOA and CBLN1 genes, or the Aldehyde dehydrogenase 1 protein. On the other hand, despite the same samples were used for both analyses, correlation between RNA and protein expression was low, as exemplified by the CST3 gene encoding for the cystatin C protein. This is the first exploratory study analyzing both gene and protein expression of laser-dissected neuronal parts from SNpc in PD. Data are available via ProteomeXchange with identifier PXD024748 and via GEO with identifier GSE 169755.
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Affiliation(s)
- Affif Zaccaria
- Neuroproteomics Group, University Medical Center, Faculty of Medicine, Geneva University, Geneva, Switzerland.
| | - Paola Antinori
- Neuroproteomics Group, University Medical Center, Faculty of Medicine, Geneva University, Geneva, Switzerland
| | - Virginie Licker
- Neuroproteomics Group, University Medical Center, Faculty of Medicine, Geneva University, Geneva, Switzerland
| | - Enikö Kövari
- Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland
| | | | - Pierre R Burkhard
- Neuroproteomics Group, University Medical Center, Faculty of Medicine, Geneva University, Geneva, Switzerland.,Department of Neurology, Geneva University Hospitals, Geneva, Switzerland
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13
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Guan PP, Jia JF, Wang P. Dietary magnesium ions block the effects of nutrient deficiency on inducing the formation of LC3B autophagosomes and disrupting the proteolysis of autolysosomes to degrade β-amyloid protein by activating cyclooloxygenase-2 at tyrosine 385. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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14
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Kim H, Sim H, Lee JE, Seo MK, Lim J, Bang Y, Nam D, Lee SY, Chung SK, Choi HJ, Park SW, Son I, Kim J, Seol W. Ciliogenesis is Not Directly Regulated by LRRK2 Kinase Activity in Neurons. Exp Neurobiol 2021; 30:232-243. [PMID: 34230223 PMCID: PMC8278138 DOI: 10.5607/en21003] [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: 03/04/2021] [Revised: 04/28/2021] [Accepted: 05/14/2021] [Indexed: 11/19/2022] Open
Abstract
Mutations in the Leucine-rich repeat kinase 2 (LRRK2) gene are the most prevalent cause of familial Parkinson’s disease (PD). The increase in LRRK2 kinase activity observed in the pathogenic G2019S mutation is important for PD development. Several studies have reported that increased LRRK2 kinase activity and treatment with LRRK2 kinase inhibitors decreased and increased ciliogenesis, respectively, in mouse embryonic fibroblasts (MEFs) and retinal pigment epithelium (RPE) cells. In contrast, treatment of SH-SY5Y dopaminergic neuronal cells with PD-causing chemicals increased ciliogenesis. Because these reports were somewhat contradictory, we tested the effect of LRRK2 kinase activity on ciliogenesis in neurons. In SH-SY5Y cells, LRRK2 inhibitor treatment slightly increased ciliogenesis, but serum starvation showed no increase. In rat primary neurons, LRRK2 inhibitor treatment repeatedly showed no significant change. Little difference was observed between primary cortical neurons prepared from wild-type (WT) and G2019S+/- mice. However, a significant increase in ciliogenesis was observed in G2019S+/- compared to WT human fibroblasts, and this pattern was maintained in neural stem cells (NSCs) differentiated from the induced pluripotent stem cells (iPSCs) prepared from the same WT/G2019S fibroblast pair. NSCs differentiated from G2019S and its gene-corrected WT counterpart iPSCs were also used to test ciliogenesis in an isogenic background. The results showed no significant difference between WT and G2019S regardless of kinase inhibitor treatment and B27-deprivation-mimicking serum starvation. These results suggest that LRRK2 kinase activity may be not a direct regulator of ciliogenesis and ciliogenesis varies depending upon the cell type or genetic background.
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Affiliation(s)
- Hyejung Kim
- InAm Neuroscience Research Center, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 15865, Korea
| | - Hyuna Sim
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea.,Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon 34141, Korea
| | - Joo-Eun Lee
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Mi Kyoung Seo
- Paik Institute for Clinical Research, Inje University College of Medicine, Busan 47392, Korea
| | - Juhee Lim
- College of Pharmacy, CHA University, Seongnam 13496, Korea
| | - Yeojin Bang
- College of Pharmacy, CHA University, Seongnam 13496, Korea
| | - Daleum Nam
- InAm Neuroscience Research Center, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 15865, Korea
| | - Seo-Young Lee
- Division of Clinical Medicine, Korea Institute of Oriental Medicine, Daejeon 34054, Korea
| | - Sun-Ku Chung
- Division of Herbal Medicine Research, Korea Institute of Oriental Medicine, Daejeon 34054, Korea
| | - Hyun Jin Choi
- College of Pharmacy, CHA University, Seongnam 13496, Korea
| | - Sung Woo Park
- Paik Institute for Clinical Research, Inje University College of Medicine, Busan 47392, Korea.,Department of Convergence Biomedical Science, Inje University College of Medicine, Busan 47392, Korea
| | - Ilhong Son
- InAm Neuroscience Research Center, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 15865, Korea.,Department of Neurology, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 15865, Korea
| | - Janghwan Kim
- Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea.,Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon 34141, Korea
| | - Wongi Seol
- InAm Neuroscience Research Center, Sanbon Medical Center, College of Medicine, Wonkwang University, Gunpo 15865, Korea
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15
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McNeill RV, Palladino VS, Brunkhorst-Kanaan N, Grimm O, Reif A, Kittel-Schneider S. Expression of the adult ADHD-associated gene ADGRL3 is dysregulated by risk variants and environmental risk factors. World J Biol Psychiatry 2021; 22:335-349. [PMID: 32787626 DOI: 10.1080/15622975.2020.1809014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES ADGRL3 is a well-replicated risk gene for adult ADHD, encoding the G protein-coupled receptor latrophilin-3 (LPHN3). However, LPHN3's potential role in pathogenesis is unclear. We aimed to determine whether ADGRL3 expression could be dysregulated by genetic risk variants and/or ADHD-associated environmental risk factors. METHODS Eighteen adult ADHD patients and healthy controls were genotyped for rs734644, rs1397547, rs1397548, rs2271338, rs2305339, rs2345039 and rs6551665 ADGRL3 SNPs, and fibroblast cells were derived from skin punches. The environmental ADHD risk factors 'low birthweight' and 'maternal smoking' were modelled in fibroblast cell culture using starvation and nicotine exposure, respectively. Quantitative real-time PCR and western blotting were performed to quantify ADGRL3 gene and protein expression under control, starvation and nicotine-exposed conditions. RESULTS Starvation was found to significantly decrease ADGRL3 expression, whereas nicotine exposure significantly increased ADGRL3 expression. rs1397547 significantly elevated ADGRL3 transcription and protein expression. rs6551665 and rs2345039 interacted with environment to modulate ADGRL3 transcription. ADGRL3 SNPs were significantly able to predict its transcription under both baseline and starvation conditions, and rs1397547 was identified as a significant independent predictor. CONCLUSIONS ADGRL3 SNPs and environmental risk factors can regulate ADGRL3 expression, providing a potential functional mechanism by which LPHN3 may play a role in ADHD pathogenesis.
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Affiliation(s)
- Rhiannon V McNeill
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Viola Stella Palladino
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - Nathalie Brunkhorst-Kanaan
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - Oliver Grimm
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - Sarah Kittel-Schneider
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Frankfurt, Frankfurt, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, University Hospital Würzburg, Würzburg, Germany
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16
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Valencia M, Kim SR, Jang Y, Lee SH. Neuronal Autophagy: Characteristic Features and Roles in Neuronal Pathophysiology. Biomol Ther (Seoul) 2021; 29:605-614. [PMID: 33875624 PMCID: PMC8551733 DOI: 10.4062/biomolther.2021.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/02/2021] [Accepted: 03/23/2021] [Indexed: 11/12/2022] Open
Abstract
Autophagy is an important degradative pathway that eliminates misfolded proteins and damaged organelles from cells. Autophagy is crucial for neuronal homeostasis and function. A lack of or deficiency in autophagy leads to the accumulation of protein aggregates, which are associated with several neurodegenerative diseases. Compared with non-neuronal cells, neurons exhibit rapid autophagic flux because damaged organelles or protein aggregates cannot be diluted in post-mitotic cells; because of this, these cells exhibit characteristic features of autophagy, such as compartment-specific autophagy, which depends on polarized structures and rapid autophagy flux. In addition, neurons exhibit compartment-specific autophagy, which depends on polarized structures. Neuronal autophagy may have additional physiological roles other than amino acid recycling. In this review, we focus on the characteristics and regulatory factors of neuronal autophagy. We also describe intracellular selective autophagy in neurons and its association with neurodegenerative diseases.
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Affiliation(s)
- McNeil Valencia
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sung Rae Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Yeseul Jang
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
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17
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Bensalem J, Fourrier C, Hein LK, Hassiotis S, Proud CG, Sargeant TJ. Inhibiting mTOR activity using AZD2014 increases autophagy in the mouse cerebral cortex. Neuropharmacology 2021; 190:108541. [PMID: 33794244 DOI: 10.1016/j.neuropharm.2021.108541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 03/16/2021] [Accepted: 03/24/2021] [Indexed: 01/18/2023]
Abstract
Autophagy is a catabolic process that collects and degrades damaged or unwanted cellular materials such as protein aggregates. Defective brain autophagy has been linked to diseases such as Alzheimer's disease. Autophagy is regulated by the protein kinase mTOR (mechanistic target of rapamycin). Although already demonstrated in vitro, it remains contentious whether inhibiting mTOR can enhance autophagy in the brain. To address this, mice were intraperitoneally injected with the mTOR inhibitor AZD2014 for seven days. mTOR complex 1 (mTORC1) activity was decreased in liver and brain. Autophagic activity was increased by AZD2014 in both organs, as measured by immunoblotting for LC3 (microtubule-associated proteins-1A/1B light chain 3B) and measurement of autophagic flux in the cerebral cortex of transgenic mice expressing the EGFP-mRFP-LC3B transgene. mTOR activity was shown to correlate with changes in LC3. Thus, we show it is possible to promote autophagy in the brain using AZD2014, which will be valuable in tackling conditions associated with defective autophagy, especially neurodegeneration.
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Affiliation(s)
- Julien Bensalem
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Célia Fourrier
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Leanne K Hein
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Sofia Hassiotis
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Christopher G Proud
- Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia
| | - Timothy J Sargeant
- Lysosomal Health in Ageing, Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, North Terrace, Adelaide, Australia.
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18
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Ferreira-Marques M, Carvalho A, Cavadas C, Aveleira CA. PI3K/AKT/MTOR and ERK1/2-MAPK signaling pathways are involved in autophagy stimulation induced by caloric restriction or caloric restriction mimetics in cortical neurons. Aging (Albany NY) 2021; 13:7872-7882. [PMID: 33714946 PMCID: PMC8034898 DOI: 10.18632/aging.202805] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 02/25/2021] [Indexed: 01/03/2023]
Abstract
Caloric restriction has been shown to robustly ameliorate age-related diseases and to prolong lifespan in several model organisms, and these beneficial effects are dependent on the stimulation of autophagy. Autophagy dysfunction contributes to the accumulation of altered macromolecules, and is a key mechanism of promoting aging and age-related disorders, as neurodegenerative ones. We have previously shown that caloric restriction (CR), and CR mimetics Neuropeptide Y (NPY) and ghrelin, stimulate autophagy in rat cortical neurons, however by unknown molecular mechanisms. Overall, we show that CR, NPY, and ghrelin stimulate autophagy through PI3K/AKT/MTOR inhibition and ERK1/2-MAPK activation. The knowledge of these kinases in autophagy regulation and the contribution to the understanding of molecular mechanism facilitates the discovery of more targeted therapeutic strategies to stimulate autophagy, which is relevant in the context of age-related disorders.
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Affiliation(s)
- Marisa Ferreira-Marques
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
| | - André Carvalho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Cláudia Cavadas
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
| | - Célia A Aveleira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
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19
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Wojnacki J, Nola S, Bun P, Cholley B, Filippini F, Pressé MT, Lipecka J, Man Lam S, N’guyen J, Simon A, Ouslimani A, Shui G, Fader CM, Colombo MI, Guerrera IC, Galli T. Role of VAMP7-Dependent Secretion of Reticulon 3 in Neurite Growth. Cell Rep 2020; 33:108536. [DOI: 10.1016/j.celrep.2020.108536] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 10/28/2020] [Accepted: 11/25/2020] [Indexed: 11/24/2022] Open
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20
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Overhoff M, De Bruyckere E, Kononenko NL. Mechanisms of neuronal survival safeguarded by endocytosis and autophagy. J Neurochem 2020; 157:263-296. [PMID: 32964462 DOI: 10.1111/jnc.15194] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/21/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022]
Abstract
Multiple aspects of neuronal physiology crucially depend on two cellular pathways, autophagy and endocytosis. During endocytosis, extracellular components either unbound or recognized by membrane-localized receptors (termed "cargo") become internalized into plasma membrane-derived vesicles. These can serve to either recycle the material back to the plasma membrane or send it for degradation to lysosomes. Autophagy also uses lysosomes as a terminal degradation point, although instead of degrading the plasma membrane-derived cargo, autophagy eliminates detrimental cytosolic material and intracellular organelles, which are transported to lysosomes by means of double-membrane vesicles, referred to as autophagosomes. Neurons, like all non-neuronal cells, capitalize on autophagy and endocytosis to communicate with the environment and maintain protein and organelle homeostasis. Additionally, the highly polarized, post-mitotic nature of neurons made them adopt these two pathways for cell-specific functions. These include the maintenance of the synaptic vesicle pool in the pre-synaptic terminal and the long-distance transport of signaling molecules. Originally discovered independently from each other, it is now clear that autophagy and endocytosis are closely interconnected and share several common participating molecules. Considering the crucial role of autophagy and endocytosis in cell type-specific functions in neurons, it is not surprising that defects in both pathways have been linked to the pathology of numerous neurodegenerative diseases. In this review, we highlight the recent knowledge of the role of endocytosis and autophagy in neurons with a special focus on synaptic physiology and discuss how impairments in genes coding for autophagy and endocytosis proteins can cause neurodegeneration.
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Affiliation(s)
- Melina Overhoff
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Elodie De Bruyckere
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Natalia L Kononenko
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
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21
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Vucicevic L, Misirkic M, Ciric D, Martinovic T, Jovanovic M, Isakovic A, Markovic I, Saponjic J, Foretz M, Rabanal-Ruiz Y, Korolchuk VI, Trajkovic V. Transcriptional block of AMPK-induced autophagy promotes glutamate excitotoxicity in nutrient-deprived SH-SY5Y neuroblastoma cells. Cell Mol Life Sci 2020; 77:3383-3399. [PMID: 31720741 PMCID: PMC11105051 DOI: 10.1007/s00018-019-03356-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 10/16/2019] [Accepted: 10/28/2019] [Indexed: 02/07/2023]
Abstract
We investigated the role of autophagy, a controlled lysosomal degradation of cellular macromolecules and organelles, in glutamate excitotoxicity during nutrient deprivation in vitro. The incubation in low-glucose serum/amino acid-free cell culture medium synergized with glutamate in increasing AMP/ATP ratio and causing excitotoxic necrosis in SH-SY5Y human neuroblastoma cells. Glutamate suppressed starvation-triggered autophagy, as confirmed by diminished intracellular acidification, lower LC3 punctuation and LC3-I conversion to autophagosome-associated LC3-II, reduced expression of proautophagic beclin-1 and ATG5, increase of the selective autophagic target NBR1, and decreased number of autophagic vesicles. Similar results were observed in PC12 rat pheochromocytoma cells. Both glutamate-mediated excitotoxicity and autophagy inhibition in starved SH-SY5Y cells were reverted by NMDA antagonist memantine and mimicked by NMDA agonists D-aspartate and ibotenate. Glutamate reduced starvation-triggered phosphorylation of the energy sensor AMP-activated protein kinase (AMPK) without affecting the activity of mammalian target of rapamycin complex 1, a major negative regulator of autophagy. This was associated with reduced mRNA levels of autophagy transcriptional activators (FOXO3, ATF4) and molecules involved in autophagy initiation (ULK1, ATG13, FIP200), autophagosome nucleation/elongation (ATG14, beclin-1, ATG5), and autophagic cargo delivery to autophagosomes (SQSTM1). Glutamate-mediated transcriptional repression of autophagy was alleviated by overexpression of constitutively active AMPK. Genetic or pharmacological AMPK activation by AMPK overexpression or metformin, as well as genetic or pharmacological autophagy induction by TFEB overexpression or lithium chloride, reduced the sensitivity of nutrient-deprived SH-SY5Y cells to glutamate excitotoxicity. These data indicate that transcriptional inhibition of AMPK-dependent cytoprotective autophagy is involved in glutamate-mediated excitotoxicity during nutrient deprivation in vitro.
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Affiliation(s)
- Ljubica Vucicevic
- Department of Neurophysiology, Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Maja Misirkic
- Department of Neurophysiology, Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Darko Ciric
- Faculty of Medicine, Institute of Histology and Embryology, University of Belgrade, Belgrade, Serbia
| | - Tamara Martinovic
- Faculty of Medicine, Institute of Histology and Embryology, University of Belgrade, Belgrade, Serbia
| | - Maja Jovanovic
- Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Isakovic
- Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Ivanka Markovic
- Faculty of Medicine, Institute of Medical and Clinical Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Jasna Saponjic
- Department of Neurobiology, Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Marc Foretz
- Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris cité, Paris, France
| | - Yoana Rabanal-Ruiz
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
- Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Viktor I Korolchuk
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Vladimir Trajkovic
- Faculty of Medicine, Institute of Microbiology and Immunology, University of Belgrade, Dr. Subotica 1, 11000, Belgrade, Serbia.
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22
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Hill SE, Colón-Ramos DA. The Journey of the Synaptic Autophagosome: A Cell Biological Perspective. Neuron 2020; 105:961-973. [PMID: 32191859 DOI: 10.1016/j.neuron.2020.01.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/23/2019] [Accepted: 01/14/2020] [Indexed: 01/13/2023]
Abstract
Autophagy is a key cellular degradative pathway, important for neuronal homeostasis and function. Disruption of autophagy is associated with neuronal dysfunction and neurodegeneration. Autophagy is compartmentalized in neurons, with specific stages of the pathway occurring in distinct subcellular compartments. Coordination of these stages drives progression of autophagy and enables clearance of substrates. Yet, we are only now learning how these distributed processes are integrated across the neuron. In this review, we focus on the cell biological course of autophagy in neurons, from biogenesis at the synapse to degradation in the soma. We describe how the steps of autophagy are distributed across neuronal subcellular compartments, how local machinery regulates autophagy, and the impact of coordinated regulation on neuronal physiology and disease. We also discuss how recent advances in our understanding of neuronal autophagic mechanisms have reframed how we think about the role of local regulation of autophagy in all tissues.
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Affiliation(s)
- Sarah E Hill
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, PO Box 9812, New Haven, CT 06536-0812, USA; Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Daniel A Colón-Ramos
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, PO Box 9812, New Haven, CT 06536-0812, USA; Instituto de Neurobiología José del Castillo, Universidad de Puerto Rico, San Juan, PR, USA.
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23
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Oliva Trejo JA, Tanida I, Suzuki C, Kakuta S, Tada N, Uchiyama Y. Characterization of starvation-induced autophagy in cerebellar Purkinje cells of pHluorin-mKate2-human LC3B transgenic mice. Sci Rep 2020; 10:9643. [PMID: 32541814 PMCID: PMC7295967 DOI: 10.1038/s41598-020-66370-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/19/2020] [Indexed: 12/25/2022] Open
Abstract
We generated a new transgenic mouse model that expresses a pHluorin-mKate2 fluorescent protein fused with human LC3B (PK-LC3 mice) for monitoring autophagy activity in neurons of the central nervous system. Histological analysis revealed fluorescent puncta in neurons of the cerebral cortex, hippocampus, cerebellar Purkinje cells, and anterior spinal regions. Using CLEM analysis, we confirmed that PK-LC3-positive puncta in the perikarya of Purkinje cells correspond to autophagic structures. To validate the usability of PK-LC3 mice, we quantified PK-LC3 puncta in Purkinje cells of mice kept in normal feeding conditions and of mice starved for 24 hours. Our results showed a significant increase in autophagosome number and in individual puncta areal size following starvation. To confirm these results, we used morphometry at the electron microscopic level to analyze the volume densities of autophagosomes and lysosomes/autolysosomes in Purkinje cells of PK-LC3 mice. The results revealed that the volume densities of autophagic structures increase significantly after starvation. Together, our data show that PK-LC3 mice are suitable for monitoring autophagy flux in Purkinje cells of the cerebellum, and potentially other areas in the central nervous system.
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Affiliation(s)
- Juan Alejandro Oliva Trejo
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, Japan
| | - Isei Tanida
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, Japan.
| | - Chigure Suzuki
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, Japan
| | - Soichiro Kakuta
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, Japan
| | - Norihiro Tada
- Research Institute for Diseases of Old Age, Juntendo University School of Medicine, Bunkyo-Ku, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, Japan.
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24
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Autophagy as a Cellular Stress Response Mechanism in the Nervous System. J Mol Biol 2020; 432:2560-2588. [PMID: 31962122 DOI: 10.1016/j.jmb.2020.01.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/11/2019] [Accepted: 01/10/2020] [Indexed: 12/13/2022]
Abstract
Cells of an organism face with various types of insults during their lifetime. Exposure to toxins, metabolic problems, ischaemia/reperfusion, physical trauma, genetic diseases, neurodegenerative diseases are among the conditions that trigger cellular stress responses. In this context, autophagy is one of the mechanisms that supports cell survival under stressful conditions. Autophagic vesicle engulfs the cargo and transports it to lysosome for degradation and turnover. As such, autophagy eliminates abnormal proteins, clears damaged organelles, limits oxidative stress and helps to improve metabolic balance. Nervous system cells and particularly postmitotic neurons are highly sensitive to a spectrum of insults, and autophagy emerges as one of the key stress response mechanism, ensuring health and survival of these vulnerable cell types. In this review, we will overview mechanisms through which cells cope with stress, and how these stress responses regulate autophagy, with a special focus on the nervous system.
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25
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High fructose diet induces early mortality via autophagy factors accumulation in the rostral ventrolateral medulla as ameliorated by pioglitazone. J Nutr Biochem 2019; 69:87-97. [PMID: 31063919 DOI: 10.1016/j.jnutbio.2019.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/11/2019] [Accepted: 03/14/2019] [Indexed: 02/07/2023]
Abstract
High fructose ingestion enhances mortality which has been linked to autonomic dysregulation. However, the underlying mechanisms are still largely unknown. In the present study, we demonstrated that 3 months of high fructose diet (HFD) ingestion induced mortality in 18-week-old Wistar Kyoto rats (WKY) during anesthesia. Concurrently, the low frequency (LF) and the high frequency (HF) elements of the power spectral analyses of SBP were increased. Of note, the decreased ratio of LF and HF (LF/HF), an index of sympathetic and parasympathetic balance, suggested an autonomic imbalance. In the rostral ventrolateral medulla (RVLM), a center of sympathetic outflow, the levels of presynaptic (synaptophysin) and postsynaptic (postsynaptic density protein 95 and phospho-Ca2+/calmodulin-dependent protein kinase II) proteins were increased. The down-regulation of insulin receptor β and insulin receptor substrate 1 suggested the status of insulin desensitization. Moreover, the up-regulation of AMP-activated protein kinase and sirtuin 1 suggested the enhancement of energy sensing to activate autophagy. Simultaneously, the accumulations of Beclin-1, ATG12 and LC3B were increased in RVLM. Pioglitazone (PIO), an insulin sensitizer, effectively relieved the accumulation of Beclin-1 and ATG12 as well as the synaptic proteins synchronized with the reverses of insulin and energy sensing signals. Moreover, the autonomic dysregulation and anesthesia-associated mortality were intervened. Together, these results suggested that the HFD-induced, anesthesia-associated mortality rate was related to the autonomic abnormality derived from the RVLM synaptic alteration, which is strongly related to insulin desensitization-associated autophagy. PIO intervened the HFD-induced mortality via reversal of the above-mentioned molecules.
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26
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Zhang JY, Lee JH, Gu X, Wei ZZ, Harris MJ, Yu SP, Wei L. Intranasally Delivered Wnt3a Improves Functional Recovery after Traumatic Brain Injury by Modulating Autophagic, Apoptotic, and Regenerative Pathways in the Mouse Brain. J Neurotrauma 2019; 35:802-813. [PMID: 29108471 DOI: 10.1089/neu.2016.4871] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Traumatic brain injury (TBI) is a prevalent disorder, but no effective therapies currently exist. An underlying pathophysiology of TBI includes the pathological elevation of autophagy. β-Catenin, a downstream mediator of the canonical Wnt pathway, is a repressor of autophagy. The Wnt/β-catenin pathway plays a crucial role in cell proliferation and neuronal plasticity/repair in the adult brain. We hypothesized that activation of this pathway could promote neuroprotection and neural regeneration following TBI. In the controlled cortical impact (CCI) model of TBI in C57BL/6 mice (total n = 160), we examined intranasal application of recombinant Wnt3a (2 μg/kg) in a short-term (1 dose/day for 2 days) and long-term (1 dose/day for 7 days) regimen. Immunohistochemistry was performed at 1 to 14 days post-TBI to assess cell death and neurovascular regeneration. Western blotting measured canonical Wnt3a activity, expression of growth factors, and cell death markers. Longitudinal behavior assays evaluated functional recovery. In short-term experiments, Wnt3a treatment with a 60-min delay post-TBI suppressed TBI-induced autophagic activity in neurons (44.3 ± 6.98 and 4.25 ± 2.53 LC3+/NeuN+ double positive cells in TBI+Saline and TBI+Wnt3a mice, respectively; p < 0.0001, n = 5/group), reduced autophagic markers light chain 3 (LC3)-II and Beclin-1, as well as injury markers caspase-3 and matrix metalloproteinase 9 (MMP-9). The Wnt3a treatment reduced cell death and contusion volume (0.72 ± 0.07 mm2 and 0.26 ± 0.04 mm2 in TBI+Saline and TBI+Wnt3a mice, respectively; p < 0.001, n = 5/group). The 7-day Wnt3a treatment increased levels of β-catenin and growth factors glial-derived growth factor (GDNF) and vascular endothelial growth factor (VEGF). This chronic Wnt3a therapy augmented neurogenesis (0.52 ± 0.09 and 1.25 ± 0.13 BrdU+/NeuN+ co-labeled cells in TBI+Saline mice and TBI+Wnt3a mice, respectively; p < 0.01, n = 6/group) and angiogenesis (0.26 ± 0.07 and 0.74 ± 0.13 BrdU+/GLUT1+ co-labeled cells in TBI+Saline and TBI+Wnt3a mice, respectively; p = 0.014, n = 6/group). The treatment improved performance in the rotarod test and adhesive removal test. Targeting the Wnt pathway implements a unique combination of protective and regenerative approaches after TBI.
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Affiliation(s)
- James Ya Zhang
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia
| | - Jin Hwan Lee
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia
| | - Xiaohuan Gu
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia
| | - Zheng Zachory Wei
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia
| | | | - Shan Ping Yu
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia
| | - Ling Wei
- 1 Department of Anesthesiology, Emory University School of Medicine , Atlanta, Georgia .,2 Department of Neurology, Emory University School of Medicine , Atlanta, Georgia
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27
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Abstract
Effective therapeutic strategy against Alzheimer's disease (AD) requires early detection of AD; however, clinical diagnosis of Alzheimer's disease (AD) is not precise and a definitive diagnosis of AD is only possible via postmortem examination for AD pathological hallmarks including senile plaques composed of Aβ and neuro fibrillary tangles composed of phosphorylated tau. Although a variety of biomarker has been developed and used in clinical setting, none of them robustly predicts subsequent clinical course of AD. Thus, it is essential to identify new biomarkers that may facilitate the diagnosis of early stages of AD, prediction of subsequent clinical course, and development of new therapeutic strategies. Given that pathological hallmarks of AD including Aβaccumulation and the presence of phosphorylated tau are also detected in peripheral tissues, AD is considered a systemic disease. Without the protection of blood-brain barrier, systemic factors can affect peripheral tissues much earlier than neurons in brain. Here, we will discuss the development of AD-like pathology in skeletal muscle and the potential use of skeletal muscle biopsy (examination for Aβaccumulation and phosphorylated tau) as a biomarker for AD.
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Affiliation(s)
- X Chen
- Department of Biomedical Sciences, University of North Dakota, USA
| | - N M Miller
- Department of Biomedical Sciences, University of North Dakota, USA
| | - Z Afghah
- Department of Biomedical Sciences, University of North Dakota, USA
| | - J D Geiger
- Department of Biomedical Sciences, University of North Dakota, USA
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28
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Autophagy as a Homeostatic Mechanism in Response to Stress Conditions in the Central Nervous System. Mol Neurobiol 2019; 56:6594-6608. [DOI: 10.1007/s12035-019-1546-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/12/2019] [Indexed: 12/11/2022]
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29
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Thellung S, Corsaro A, Nizzari M, Barbieri F, Florio T. Autophagy Activator Drugs: A New Opportunity in Neuroprotection from Misfolded Protein Toxicity. Int J Mol Sci 2019; 20:ijms20040901. [PMID: 30791416 PMCID: PMC6412775 DOI: 10.3390/ijms20040901] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/11/2019] [Accepted: 02/14/2019] [Indexed: 02/06/2023] Open
Abstract
The aim of this review is to critically analyze promises and limitations of pharmacological inducers of autophagy against protein misfolding-associated neurodegeneration. Effective therapies against neurodegenerative disorders can be developed by regulating the “self-defense” equipment of neurons, such as autophagy. Through the degradation and recycling of the intracellular content, autophagy promotes neuron survival in conditions of trophic factor deprivation, oxidative stress, mitochondrial and lysosomal damage, or accumulation of misfolded proteins. Autophagy involves the activation of self-digestive pathways, which is different for dynamics (macro, micro and chaperone-mediated autophagy), or degraded material (mitophagy, lysophagy, aggrephagy). All neurodegenerative disorders share common pathogenic mechanisms, including the impairment of autophagic flux, which causes the inability to remove the neurotoxic oligomers of misfolded proteins. Pharmacological activation of autophagy is typically achieved by blocking the kinase activity of mammalian target of rapamycin (mTOR) enzymatic complex 1 (mTORC1), removing its autophagy suppressor activity observed under physiological conditions; acting in this way, rapamycin provided the first proof of principle that pharmacological autophagy enhancement can induce neuroprotection through the facilitation of oligomers’ clearance. The demand for effective disease-modifying strategies against neurodegenerative disorders is currently stimulating the development of a wide number of novel molecules, as well as the re-evaluation of old drugs for their pro-autophagic potential.
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Affiliation(s)
- Stefano Thellung
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Alessandro Corsaro
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Mario Nizzari
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Federica Barbieri
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Tullio Florio
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
- IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy.
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30
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Ling SC, Dastidar SG, Tokunaga S, Ho WY, Lim K, Ilieva H, Parone PA, Tyan SH, Tse TM, Chang JC, Platoshyn O, Bui NB, Bui A, Vetto A, Sun S, McAlonis-Downes M, Han JS, Swing D, Kapeli K, Yeo GW, Tessarollo L, Marsala M, Shaw CE, Tucker-Kellogg G, La Spada AR, Lagier-Tourenne C, Da Cruz S, Cleveland DW. Overriding FUS autoregulation in mice triggers gain-of-toxic dysfunctions in RNA metabolism and autophagy-lysosome axis. eLife 2019; 8:40811. [PMID: 30747709 PMCID: PMC6389288 DOI: 10.7554/elife.40811] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 02/11/2019] [Indexed: 12/12/2022] Open
Abstract
Mutations in coding and non-coding regions of FUS cause amyotrophic lateral sclerosis (ALS). The latter mutations may exert toxicity by increasing FUS accumulation. We show here that broad expression within the nervous system of wild-type or either of two ALS-linked mutants of human FUS in mice produces progressive motor phenotypes accompanied by characteristic ALS-like pathology. FUS levels are autoregulated by a mechanism in which human FUS downregulates endogenous FUS at mRNA and protein levels. Increasing wild-type human FUS expression achieved by saturating this autoregulatory mechanism produces a rapidly progressive phenotype and dose-dependent lethality. Transcriptome analysis reveals mis-regulation of genes that are largely not observed upon FUS reduction. Likely mechanisms for FUS neurotoxicity include autophagy inhibition and defective RNA metabolism. Thus, our results reveal that overriding FUS autoregulation will trigger gain-of-function toxicity via altered autophagy-lysosome pathway and RNA metabolism function, highlighting a role for protein and RNA dyshomeostasis in FUS-mediated toxicity.
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Affiliation(s)
- Shuo-Chien Ling
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States.,Department of Neurosciences, University of California, San Diego, San Diego, United States.,Department of Physiology, National University of Singapore, Singapore, Singapore.,Neurobiology/Ageing Programme, National University of Singapore, Singapore, Singapore.,Program in Neuroscience and Behavior Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Somasish Ghosh Dastidar
- Sanford Consortium for Regenerative Medicine, University of California, San Diego, San Diego, United States
| | - Seiya Tokunaga
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Wan Yun Ho
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Kenneth Lim
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Hristelina Ilieva
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Philippe A Parone
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Sheue-Houy Tyan
- Department of Neurosciences, University of California, San Diego, San Diego, United States.,Department of Medicine, National University of Singapore, Singapore, Singapore
| | - Tsemay M Tse
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Jer-Cherng Chang
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Oleksandr Platoshyn
- Department of Anesthesiology, University of California, San Diego, San Diego, United States
| | - Ngoc B Bui
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Anh Bui
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Anne Vetto
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Shuying Sun
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Melissa McAlonis-Downes
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Joo Seok Han
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Debbie Swing
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, United States
| | - Katannya Kapeli
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States.,Department of Physiology, National University of Singapore, Singapore, Singapore.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, San Diego, United States
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, United States
| | - Martin Marsala
- Department of Anesthesiology, University of California, San Diego, San Diego, United States
| | - Christopher E Shaw
- Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Greg Tucker-Kellogg
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Albert R La Spada
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States.,Department of Neurosciences, University of California, San Diego, San Diego, United States.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, San Diego, United States
| | - Clotilde Lagier-Tourenne
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Neurosciences, University of California, San Diego, San Diego, United States
| | - Sandrine Da Cruz
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States.,Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States.,Department of Neurosciences, University of California, San Diego, San Diego, United States
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31
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Alvarez-Flores MP, Hébert A, Gouelle C, Geller S, Chudzinski-Tavassi AM, Pellerin L. Neuroprotective effect of rLosac on supplement-deprived mouse cultured cortical neurons involves maintenance of monocarboxylate transporter MCT2 protein levels. J Neurochem 2018; 148:80-96. [PMID: 30347438 DOI: 10.1111/jnc.14617] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 09/02/2018] [Accepted: 10/17/2018] [Indexed: 01/08/2023]
Abstract
The recombinant Lonomia obliqua Stuart-factor activator (rLosac) is a recombinant hemolin which belongs to the immunoglobulin superfamily of cell adhesion molecules. It is capable of inducing pro-survival activity in serum-deprived human umbilical vein endothelial cells (HUVECs) and fibroblasts by increasing mitochondrial metabolism. We hypothesize that it could promote neuronal survival by acting on neuroenergetics. Our study reveals that treatment of primary mouse cortical neurons cultured in neurobasal medium lacking B27 supplement with rLosac led to an enhancement of cell viability in a time- and concentration-dependent manner. In parallel, preserved or enhanced phosphorylation of Akt, p44, and p42 MAPK, as well as mTOR was observed following treatment with rLosac. During deprivation, as assessed by western blot and qRT-PCR, protein and mRNA expression of MCT2 (the predominant neuronal monocarboxylate transporter allowing lactate use as an alternative energy substrate) decreased significantly in B27 supplement-deprived cortical neurons and was hardly detected after 24 h of deprivation. Interestingly, rLosac maintained MCT2 protein expression after 24 h of deprivation including at the cell surface without preventing mRNA loss. MCT2 knockdown reduced rLosac-enhanced cell viability, confirming its involvement in rLosac effect. Enhanced uptake of lactate was detected following rLosac treatment and might contribute to rLosac-enhanced viability during deprivation. In the presence of both lactate and rLosac, cell viability was higher than in the presence of lactate alone. Our observations suggest that rLosac promotes cell viability in stressed (B27 supplement-deprived) neurons by facilitating the use of lactate as energy substrate via the preservation of MCT2 protein expression. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Miryam P Alvarez-Flores
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.,Laboratory of Molecular Biology - Centre of Excellence in New Target Discover CENTD, Butantan Institute, São Paulo, Brazil
| | - Audrey Hébert
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Cathy Gouelle
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Sarah Geller
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Ana M Chudzinski-Tavassi
- Laboratory of Molecular Biology - Centre of Excellence in New Target Discover CENTD, Butantan Institute, São Paulo, Brazil
| | - Luc Pellerin
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.,Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536 CNRS, LabEx TRAIL-IBIO, Université de Bordeaux, Bordeaux Cedex, France
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32
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Song S, Wu S, Wang Y, Wang Z, Ye C, Song R, Song D, Ruan Y. 17β-estradiol inhibits human umbilical vascular endothelial cell senescence by regulating autophagy via p53. Exp Gerontol 2018; 114:57-66. [PMID: 30399406 DOI: 10.1016/j.exger.2018.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cell (VEC) senescence is an initiating factor in numerous cardiovascular diseases. Recent studies showed that 17β-estradiol (17β-E2), an estrogen with numerous biological activities such as inhibition of atherosclerosis, protects VECs from senescence. However, the effects of 17β-E2 on human umbilical VECs (HUVECs) remain unknown. This study investigated the anti-senescent effect of 17β-E2 on HUVECs and explored the underlying mechanism with respect to autophagy and p53 activity. First, rapamycin and 3-methyladenine were used to clarify the relationship between autophagy and senescence in HUVECs, and an inverse relationship was demonstrated. Next, the effect of 17β-E2 on H2O2-induced senescence of HUVECs was examined. Increased autophagy induced by 17β-E2 inhibited H2O2-induced senescence of HUVECs, increased cell viability, and maintained HUVEC morphology. 17β-E2 pre-treatment also decreased cell cycle arrest, decreased the dephosphorylation of Rb, decreased the production of ET-1, and increased the production of NO. Most importantly, 17β-E2 pre-treatment increased autophagy by activating p53 and its downstream effector p53-upregulated modulator of apoptosis (PUMA). Overall, our data indicate the critical role of autophagy in the anti-senescent effect of 17β-E2 on HUVECs.
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Affiliation(s)
- Shicong Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Saizhu Wu
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuyan Wang
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhiwei Wang
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Changxiong Ye
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Rui Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Dongqing Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yunjun Ruan
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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33
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Catanese A, Garrido D, Walther P, Roselli F, Boeckers TM. Nutrient limitation affects presynaptic structures through dissociable Bassoon autophagic degradation and impaired vesicle release. J Cereb Blood Flow Metab 2018; 38:1924-1939. [PMID: 29972341 PMCID: PMC6259322 DOI: 10.1177/0271678x18786356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Acute mismatch between metabolic requirements of neurons and nutrients/growth factors availability characterizes several neurological conditions such as traumatic brain injury, stroke and hypoglycemia. Although the effects of this mismatch have been investigated at cell biological level, the effects on synaptic structure and function are less clear. Since synaptic activity is the most energy-demanding neuronal function and it is directly linked to neuronal networks functionality, we have explored whether nutrient limitation (NL) affects the ultrastructure, function and composition of pre and postsynaptic terminals. We show that upon NL, presynaptic terminals show disorganized vesicle pools and reduced levels of the active zone protein Bassoon (but not of Piccolo). Moreover, NL triggers an impaired vesicle release, which is reversed by re-administration of glucose but not by the blockade of autophagic or proteasomal protein degradation. This reveals a dissociable correlation between presynaptic architecture and vesicle release, since restoring vesicle fusion does not necessarily depend from the rescue of Bassoon levels. Thus, our data show that the presynaptic compartment is highly sensitive to NL and the rescue of presynaptic function requires re-establishment of the metabolic supply rather than preventing local protein degradation.
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Affiliation(s)
- Alberto Catanese
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,2 International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Ulm, Germany
| | - Débora Garrido
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,2 International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Ulm, Germany
| | - Paul Walther
- 3 Electron Microscopy Institute, Ulm University, Ulm, Germany
| | - Francesco Roselli
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,4 Department of Neurology, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
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34
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Dickey AS, Sanchez DN, Arreola M, Sampat KR, Fan W, Arbez N, Akimov S, Van Kanegan MJ, Ohnishi K, Gilmore-Hall SK, Flores AL, Nguyen JM, Lomas N, Hsu CL, Lo DC, Ross CA, Masliah E, Evans RM, La Spada AR. PPARδ activation by bexarotene promotes neuroprotection by restoring bioenergetic and quality control homeostasis. Sci Transl Med 2018; 9:9/419/eaal2332. [PMID: 29212711 DOI: 10.1126/scitranslmed.aal2332] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 08/09/2017] [Indexed: 01/02/2023]
Abstract
Neurons must maintain protein and mitochondrial quality control for optimal function, an energetically expensive process. The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that promote mitochondrial biogenesis and oxidative metabolism. We recently determined that transcriptional dysregulation of PPARδ contributes to Huntington's disease (HD), a progressive neurodegenerative disorder resulting from a CAG-polyglutamine repeat expansion in the huntingtin gene. We documented that the PPARδ agonist KD3010 is an effective therapy for HD in a mouse model. PPARδ forms a heterodimer with the retinoid X receptor (RXR), and RXR agonists are capable of promoting PPARδ activation. One compound with potent RXR agonist activity is the U.S. Food and Drug Administration-approved drug bexarotene. We tested the therapeutic potential of bexarotene in HD and found that bexarotene was neuroprotective in cellular models of HD, including medium spiny-like neurons generated from induced pluripotent stem cells (iPSCs) derived from patients with HD. To evaluate bexarotene as a treatment for HD, we treated the N171-82Q mouse model with the drug and found that bexarotene improved motor function, reduced neurodegeneration, and increased survival. To determine the basis for PPARδ neuroprotection, we evaluated metabolic function and noted markedly impaired oxidative metabolism in HD neurons, which was rescued by bexarotene or KD3010. We examined mitochondrial and protein quality control in cellular models of HD and observed that treatment with a PPARδ agonist promoted cellular quality control. By boosting cellular activities that are dysfunctional in HD, PPARδ activation may have therapeutic applications in HD and potentially other neurodegenerative diseases.
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Affiliation(s)
- Audrey S Dickey
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dafne N Sanchez
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Martin Arreola
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kunal R Sampat
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Weiwei Fan
- Gene Expression Laboratory, Salk Institute for Biological Studies, San Diego, CA 92037, USA
| | - Nicolas Arbez
- Departments of Psychiatry, Neurology, and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Sergey Akimov
- Departments of Psychiatry, Neurology, and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Michael J Van Kanegan
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kohta Ohnishi
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - April L Flores
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Janice M Nguyen
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicole Lomas
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cynthia L Hsu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Donald C Lo
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Christopher A Ross
- Departments of Psychiatry, Neurology, and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Eliezer Masliah
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies, San Diego, CA 92037, USA.,Howard Hughes Medical Institute, Salk Institute for Biological Studies, San Diego, CA 92037, USA
| | - Albert R La Spada
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA. .,Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.,Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.,Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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35
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Lüningschrör P, Sendtner M. Autophagy in the presynaptic compartment. Curr Opin Neurobiol 2018; 51:80-85. [DOI: 10.1016/j.conb.2018.02.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/20/2018] [Accepted: 02/26/2018] [Indexed: 11/28/2022]
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36
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Regulation and Roles of Autophagy at Synapses. Trends Cell Biol 2018; 28:646-661. [DOI: 10.1016/j.tcb.2018.03.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/12/2018] [Accepted: 03/30/2018] [Indexed: 12/21/2022]
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37
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Ehrnhoefer DE, Martin DDO, Schmidt ME, Qiu X, Ladha S, Caron NS, Skotte NH, Nguyen YTN, Vaid K, Southwell AL, Engemann S, Franciosi S, Hayden MR. Preventing mutant huntingtin proteolysis and intermittent fasting promote autophagy in models of Huntington disease. Acta Neuropathol Commun 2018; 6:16. [PMID: 29510748 PMCID: PMC5839066 DOI: 10.1186/s40478-018-0518-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/12/2018] [Indexed: 12/20/2022] Open
Abstract
Huntington disease (HD) is caused by the expression of mutant huntingtin (mHTT) bearing a polyglutamine expansion. In HD, mHTT accumulation is accompanied by a dysfunction in basal autophagy, which manifests as specific defects in cargo loading during selective autophagy. Here we show that the expression of mHTT resistant to proteolysis at the caspase cleavage site D586 (C6R mHTT) increases autophagy, which may be due to its increased binding to the autophagy adapter p62. This is accompanied by faster degradation of C6R mHTT in vitro and a lack of mHTT accumulation the C6R mouse model with age. These findings may explain the previously observed neuroprotective properties of C6R mHTT. As the C6R mutation cannot be easily translated into a therapeutic approach, we show that a scheduled feeding paradigm is sufficient to lower mHTT levels in YAC128 mice expressing cleavable mHTT. This is consistent with a previous model, where the presence of cleavable mHTT impairs basal autophagy, while fasting-induced autophagy remains functional. In HD, mHTT clearance and autophagy may become increasingly impaired as a function of age and disease stage, because of gradually increased activity of mHTT-processing enzymes. Our findings imply that mHTT clearance could be enhanced by a regulated dietary schedule that promotes autophagy.
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Cao C, Gao T, Cheng Y, Cheng M, Su T, Xi F, Wu C, Yu W. Hypothalamic AMPK-induced autophagy ameliorates hypercatabolism in septic rats by regulating POMC expression. Biochem Biophys Res Commun 2018; 497:1089-1096. [PMID: 29496447 DOI: 10.1016/j.bbrc.2018.02.184] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 02/24/2018] [Indexed: 12/13/2022]
Abstract
Hypercatabolism plays a critical role in the pathogenesis of post-critical care debility in critical patients. Central nervous system may exerte a critical role in the regulation of hypercatabolism. However, little is known about the exact mechanisms of the central role. Here, we reported that actived hypothalamic AMP-activated protein kinase (AMPK)-induced autophagy modulated the expression of POMC to ameliorate hypercatabolism in septic rats. Firstly, rats were i.c.v. injected with the lentiviral vector containing shRNA against POMC. Two weeks after injections, rats were intraperitoneally injected with LPS or saline. Twenty-four hours later, blood, skeletal muscle and hypothalamus tissues were obtained. Hypercatabolism markers and neuropeptides expression were detected. Then, rats were injected with AICAR or saline into third ventricle and promptly intraperitoneally injected with LPS or saline. Twenty-four hours after infection, blood, skeletal muscle and hypothalamus tissues were obtained. Hypercatabolism, hypothalamic AMPK-induced autophagy markers and neuropeptides expression were also detected. Results showed that sepsis would decrease the level of hypothalamic autophagy accompany with the alterations of POMC expression and hypercatabolism. Knocking out hypothalamus POMC expression could significantly ameliorate hypercatabolism. Moreover, Central activation of AMPK-induced autophagy pathway via third ventricle injection of AICAR, an AMPK activator, could efficiently ameliorate hypercatabolism as well as attenuate the elevated POMC expression rather than other neuropeptides. Taken together, these results suggested that hypothalamic AMPK-autophagy pathway as a regulatory pathway for POMC expression was essential for hypercatabolism during sepsis. And hypothalamic AMPK-autophagy activation could attenuate the POMC expression to ameliorate hypercatabolism. Pharmaceuticals with the ability of activating hypothalamic AMPK-autophagy pathway may be a therapeutic potential for hypercatabolism in septic patients.
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Affiliation(s)
- Chun Cao
- Department of Intensive Care Unit, The Affliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Tao Gao
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Yan Cheng
- Department of Intensive Care Unit, The Affliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Minhua Cheng
- Department of Intensive Care Unit, The Affliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Ting Su
- Department of Intensive Care Unit, The Affliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Fengchan Xi
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Cuili Wu
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Wenkui Yu
- Department of Intensive Care Unit, The Affliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210002, China.
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39
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Chang YC, Liu HW, Chen YT, Chen YA, Chen YJ, Chang SJ. Resveratrol protects muscle cells against palmitate-induced cellular senescence and insulin resistance through ameliorating autophagic flux. J Food Drug Anal 2018; 26:1066-1074. [PMID: 29976399 PMCID: PMC9303021 DOI: 10.1016/j.jfda.2018.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 12/30/2022] Open
Abstract
Skeletal muscle, a highly metabolic tissue, is particularly vulnerable to increased levels of saturated free fatty acids (FFAs). The role of autophagy in saturated FFAs-induced cellular senescence and insulin resistance in skeletal muscle remains unclear. Therefore, the present study was aimed to explore autophagic flux in cellular senescence and insulin resistance induced by palmitate in muscle cells, and whether resveratrol limited these responses. Our results showed that palmitate induced cellular senescence in both myoblasts and myotubes. In addition, palmitate delayed differentiation in myoblasts and inhibited expression of insulin-stimulated p-AKTSer473 in myotubes. The accumulations of autophagosome assessed by tandem fluorescent-tagged LC3 demonstrated that autophagic flux was impaired in both palmitate-treated myoblasts and myotubes. Resveratrol protected muscle cells from palmitate-induced cellular senescence, apoptosis during differentiation, and insulin resistance via ameliorating autophagic flux. The direct influence of autophagic flux on development of cellular senescence and insulin resistance was confirmed by blockage of autophagic flux with chloroquine. In conclusion, impairment of autophagic flux is crucial for palmitate-induced cellular senescence and insulin resistance in muscle cells. Restoring autophagic flux by resveratrol could be a promising approach to prevent cellular senescence and ameliorate insulin resistance in muscle.
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Affiliation(s)
- Yun-Ching Chang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Wen Liu
- Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan
| | - Yi-Tien Chen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan; School of Food Safety, Taipei Medical University, Taipei, Taiwan
| | - Yun-An Chen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Yen-Ju Chen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Sue-Joan Chang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
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40
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Ntsapi C, Lumkwana D, Swart C, du Toit A, Loos B. New Insights Into Autophagy Dysfunction Related to Amyloid Beta Toxicity and Neuropathology in Alzheimer's Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 336:321-361. [DOI: 10.1016/bs.ircmb.2017.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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41
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Moruno Manchon JF, Uzor NE, Finkbeiner S, Tsvetkov AS. SPHK1/sphingosine kinase 1-mediated autophagy differs between neurons and SH-SY5Y neuroblastoma cells. Autophagy 2018; 12:1418-24. [PMID: 27467777 DOI: 10.1080/15548627.2016.1183082] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Although implicated in neurodegeneration, autophagy has been characterized mostly in yeast and mammalian non-neuronal cells. In a recent study, we sought to determine if SPHK1 (sphingosine kinase 1), implicated previously in macroautophagy/autophagy in cancer cells, regulates autophagy in neurons. SPHK1 synthesizes sphingosine-1-phosphate (S1P), a bioactive lipid involved in cell survival. In our study, we discovered that, when neuronal autophagy is pharmacologically stimulated, SPHK1 relocalizes to the endocytic and autophagic organelles. Interestingly, in non-neuronal cells stimulated with growth factors, SPHK1 translocates to the plasma membrane, where it phosphorylates sphingosine to produce S1P. Whether SPHK1 also binds to the endocytic and autophagic organelles in non-neuronal cells upon induction of autophagy has not been demonstrated. Here, we determined if the effect in neurons is operant in the SH-SY5Y neuroblastoma cell line. In both non-differentiated and differentiated SH-SY5Y cells, a short incubation of cells in amino acid-free medium stimulated the formation of SPHK1-positive puncta, as in neurons. We also found that, unlike neurons in which these puncta represent endosomes, autophagosomes, and amphisomes, in SH-SY5Y cells SPHK1 is bound only to the endosomes. In addition, a dominant negative form of SPHK1 was very toxic to SH-SY5Y cells, but cultured primary cortical neurons tolerated it significantly better. These results suggest that autophagy in neurons is regulated by mechanisms that differ, at least in part, from those in SH-SY5Y cells.
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Affiliation(s)
- Jose Felix Moruno Manchon
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA
| | - Ndidi-Ese Uzor
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
| | - Steven Finkbeiner
- c Gladstone Institute of Neurological Disease and the Taube/Koret Center for Neurodegenerative Disease Research , San Francisco , CA , USA.,d Departments of Neurology and Physiology , University of California , San Francisco , CA , USA
| | - Andrey S Tsvetkov
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
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42
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Ferreira-Marques M, Aveleira CA, Carmo-Silva S, Botelho M, Pereira de Almeida L, Cavadas C. Caloric restriction stimulates autophagy in rat cortical neurons through neuropeptide Y and ghrelin receptors activation. Aging (Albany NY) 2017; 8:1470-84. [PMID: 27441412 PMCID: PMC4993343 DOI: 10.18632/aging.100996] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 06/30/2016] [Indexed: 12/21/2022]
Abstract
Caloric restriction is an anti-aging intervention known to extend lifespan in several experimental models, at least in part, by stimulating autophagy. Caloric restriction increases neuropeptide Y (NPY) in the hypothalamus and plasma ghrelin, a peripheral gut hormone that acts in hypothalamus to modulate energy homeostasis. NPY and ghrelin have been shown to be neuroprotective in different brain areas and to induce several physiological modifications similar to those induced by caloric restriction. However, the effect of NPY and ghrelin in autophagy in cortical neurons is currently not known. Using a cell culture of rat cortical neurons we investigate the involvement of NPY and ghrelin in caloric restriction-induced autophagy. We observed that a caloric restriction mimetic cell culture medium stimulates autophagy in rat cortical neurons and NPY or ghrelin receptor antagonists blocked this effect. On the other hand, exogenous NPY or ghrelin stimulate autophagy in rat cortical neurons. Moreover, NPY mediates the stimulatory effect of ghrelin on autophagy in rat cortical neurons. Since autophagy impairment occurs in aging and age-related neurodegenerative diseases, NPY and ghrelin synergistic effect on autophagy stimulation may suggest a new strategy to delay aging process.
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Affiliation(s)
| | - Célia A Aveleira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Sara Carmo-Silva
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Mariana Botelho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Luís Pereira de Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Cláudia Cavadas
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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43
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Vijayan V, Verstreken P. Autophagy in the presynaptic compartment in health and disease. J Cell Biol 2017; 216:1895-1906. [PMID: 28515275 PMCID: PMC5496617 DOI: 10.1083/jcb.201611113] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/30/2017] [Accepted: 04/25/2017] [Indexed: 12/25/2022] Open
Abstract
Vijayan and Verstreken review the process of autophagy in the synapse and the role of autophagy in maintaining neuronal function. Synapses are functionally distinct neuronal compartments that are critical for brain function, with synaptic dysfunction being an early pathological feature in aging and disease. Given the large number of proteins needed for synaptic function, the proliferation of defective proteins and the subsequent loss of protein homeostasis may be a leading cause of synaptic dysfunction. Autophagic mechanisms are cellular digestion processes that recycle cellular components and contribute to protein homeostasis. Autophagy is important within the nervous system, but its function in specific compartments such as the synapse has been unclear. Evidence from research on both autophagy and synaptic function suggests that there are links between the two and that synaptic homeostasis during aging requires autophagy to regulate protein homeostasis. Exciting new work on autophagy-modulating proteins that are enriched at the synapse has begun to link autophagy to synapses and synaptic dysfunction in disease. A better understanding of these links will help us harness the potential therapeutic benefits of autophagy in combating age-related disorders of the nervous system.
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Affiliation(s)
- Vinoy Vijayan
- Department of Neurosciences, Katholieke University Leuven, 3000 Leuven, Belgium .,Leuven Institute for Neurodegenerative Disease, Katholieke University Leuven, 3000 Leuven, Belgium.,VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
| | - Patrik Verstreken
- Department of Neurosciences, Katholieke University Leuven, 3000 Leuven, Belgium.,Leuven Institute for Neurodegenerative Disease, Katholieke University Leuven, 3000 Leuven, Belgium.,VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
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44
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Assessing Basal and Acute Autophagic Responses in the Adult Drosophila Nervous System: The Impact of Gender, Genetics and Diet on Endogenous Pathway Profiles. PLoS One 2016; 11:e0164239. [PMID: 27711219 PMCID: PMC5053599 DOI: 10.1371/journal.pone.0164239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/21/2016] [Indexed: 11/28/2022] Open
Abstract
The autophagy pathway is critical for the long-term homeostasis of cells and adult organisms and is often activated during periods of stress. Reduced pathway efficacy plays a central role in several progressive neurological disorders that are associated with the accumulation of cytotoxic peptides and protein aggregates. Previous studies have shown that genetic and transgenic alterations to the autophagy pathway impacts longevity and neural aggregate profiles of adult Drosophila. In this study, we have identified methods to measure the acute in vivo induction of the autophagy pathway in the adult fly CNS. Our findings indicate that the genotype, age, and gender of adult flies can influence pathway responses. Further, we demonstrate that middle-aged male flies exposed to intermittent fasting (IF) had improved neuronal autophagic profiles. IF-treated flies also had lower neural aggregate profiles, maintained more youthful behaviors and longer lifespans, when compared to ad libitum controls. In summary, we present methodology to detect dynamic in vivo changes that occur to the autophagic profiles in the adult Drosophila CNS and that a novel IF-treatment protocol improves pathway response in the aging nervous system.
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45
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Oh TS, Cho H, Cho JH, Yu SW, Kim EK. Hypothalamic AMPK-induced autophagy increases food intake by regulating NPY and POMC expression. Autophagy 2016; 12:2009-2025. [PMID: 27533078 DOI: 10.1080/15548627.2016.1215382] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hypothalamic AMP-activated protein kinase (AMPK) plays important roles in the regulation of food intake by altering the expression of orexigenic or anorexigenic neuropeptides. However, little is known about the mechanisms of this regulation. Here, we report that hypothalamic AMPK modulates the expression of NPY (neuropeptide Y), an orexigenic neuropeptide, and POMC (pro-opiomelanocortin-α), an anorexigenic neuropeptide, by regulating autophagic activity in vitro and in vivo. In hypothalamic cell lines subjected to low glucose availability such as 2-deoxy-d-glucose (2DG)-induced glucoprivation or glucose deprivation, autophagy was induced via the activation of AMPK, which regulates ULK1 and MTOR complex 1 followed by increased Npy and decreased Pomc expression. Pharmacological or genetic inhibition of autophagy diminished the effect of AMPK on neuropeptide expression in hypothalamic cell lines. Moreover, AMPK knockdown in the arcuate nucleus of the hypothalamus decreased autophagic activity and changed Npy and Pomc expression, leading to a reduction in food intake and body weight. AMPK knockdown abolished the orexigenic effects of intraperitoneal 2DG injection by decreasing autophagy and changing Npy and Pomc expression in mice fed a high-fat diet. We suggest that the induction of autophagy is a possible mechanism of AMPK-mediated regulation of neuropeptide expression and control of feeding in response to low glucose availability.
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Affiliation(s)
- Tae Seok Oh
- a Department of Brain & Cognitive Sciences , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea
| | - Hanchae Cho
- a Department of Brain & Cognitive Sciences , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea
| | - Jae Hyun Cho
- a Department of Brain & Cognitive Sciences , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea
| | - Seong-Woon Yu
- a Department of Brain & Cognitive Sciences , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea
| | - Eun-Kyoung Kim
- a Department of Brain & Cognitive Sciences , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea.,b Neurometabolomics Research Center , Daegu Gyeongbuk Institute of Science & Technology , Dalseong-gun , Daegu , Korea
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46
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Maday S, Holzbaur ELF. Compartment-Specific Regulation of Autophagy in Primary Neurons. J Neurosci 2016; 36:5933-45. [PMID: 27251616 PMCID: PMC4887563 DOI: 10.1523/jneurosci.4401-15.2016] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 03/25/2016] [Accepted: 03/31/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Autophagy is an essential degradative pathway that maintains neuronal homeostasis and prevents axon degeneration. Initial observations suggest that autophagy is spatially regulated in neurons, but how autophagy is regulated in distinct neuronal compartments is unclear. Using live-cell imaging in mouse hippocampal neurons, we establish the compartment-specific mechanisms of constitutive autophagy under basal conditions, as well as in response to stress induced by nutrient deprivation. We find that at steady state, the cell soma contains populations of autophagosomes derived from distinct neuronal compartments and defined by differences in maturation state and dynamics. Axonal autophagosomes enter the soma and remain confined within the somatodendritic domain. This compartmentalization likely facilitates cargo degradation by enabling fusion with proteolytically active lysosomes enriched in the soma. In contrast, autophagosomes generated within the soma are less mobile and tend to cluster. Surprisingly, starvation did not induce autophagy in either the axonal or somatodendritic compartment. While starvation robustly decreased mTORC1 signaling in neurons, this decrease was not sufficient to activate autophagy. Furthermore, pharmacological inhibition of mammalian target of rapamycin with Torin1 also was not sufficient to markedly upregulate neuronal autophagy. These observations suggest that the primary physiological function of autophagy in neurons may not be to mobilize amino acids and other biosynthetic building blocks in response to starvation, in contrast to findings in other cell types. Rather, constitutive autophagy in neurons may function to maintain cellular homeostasis by balancing synthesis and degradation, especially within distal axonal processes far removed from the soma. SIGNIFICANCE STATEMENT Autophagy is an essential homeostatic process in neurons, but neuron-specific mechanisms are poorly understood. Here, we compare autophagosome dynamics within neuronal compartments. Axonal autophagy is a vectorial process that delivers cargo from the distal axon to the soma. The soma, however, contains autophagosomes at different maturation states, including input received from the axon combined with locally generated autophagosomes. Once in the soma, autophagosomes are confined to the somatodendritic domain, facilitating cargo degradation and recycling of biosynthetic building blocks to primary sites of protein synthesis. Neuronal autophagy is not robustly upregulated in response to starvation or mammalian target of rapamycin inhibition, suggesting that constitutive autophagy in neurons maintains homeostasis by playing an integral role in regulating the quality of the neuronal proteome.
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Affiliation(s)
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
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47
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Chung KM, Jeong EJ, Park H, An HK, Yu SW. Mediation of Autophagic Cell Death by Type 3 Ryanodine Receptor (RyR3) in Adult Hippocampal Neural Stem Cells. Front Cell Neurosci 2016; 10:116. [PMID: 27199668 PMCID: PMC4858590 DOI: 10.3389/fncel.2016.00116] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/21/2016] [Indexed: 11/15/2022] Open
Abstract
Cytoplasmic Ca2+ actively engages in diverse intracellular processes from protein synthesis, folding and trafficking to cell survival and death. Dysregulation of intracellular Ca2+ levels is observed in various neuropathological states including Alzheimer’s and Parkinson’s diseases. Ryanodine receptors (RyRs) and inositol 1,4,5-triphosphate receptors (IP3Rs), the main Ca2+ release channels located in endoplasmic reticulum (ER) membranes, are known to direct various cellular events such as autophagy and apoptosis. Here we investigated the intracellular Ca2+-mediated regulation of survival and death of adult hippocampal neural stem (HCN) cells utilizing an insulin withdrawal model of autophagic cell death (ACD). Despite comparable expression levels of RyR and IP3R transcripts in HCN cells at normal state, the expression levels of RyRs—especially RyR3—were markedly upregulated upon insulin withdrawal. While treatment with the RyR agonist caffeine significantly promoted the autophagic death of insulin-deficient HCN cells, treatment with its inhibitor dantrolene prevented the induction of autophagy following insulin withdrawal. Furthermore, CRISPR/Cas9-mediated knockout of the RyR3 gene abolished ACD of HCN cells. This study delineates a distinct, RyR3-mediated ER Ca2+ regulation of autophagy and programmed cell death in neural stem cells. Our findings provide novel insights into the critical, yet understudied mechanisms underlying the regulatory function of ER Ca2+ in neural stem cell biology.
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Affiliation(s)
- Kyung Min Chung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
| | - Eun-Ji Jeong
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
| | - Hyunhee Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
| | - Hyun-Kyu An
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
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48
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Xie X, Zhang T, Zhao S, Li W, Ma L, Ding M, Liu Y. Effects of n-3 polyunsaturated fatty acids high fat diet intervention on the synthesis of hepatic high-density lipoprotein cholesterol in obesity-insulin resistance rats. Lipids Health Dis 2016; 15:81. [PMID: 27101976 PMCID: PMC4840880 DOI: 10.1186/s12944-016-0250-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 04/14/2016] [Indexed: 12/21/2022] Open
Abstract
Background n-3 polyunsaturated fatty acids (PUFA) have previously been demonstrated in association with a reduced risk of chronic diseases, including insulin resistance, cancer and cardiovascular disease. In the present study, we analyzed the effects of n-3 PUFA-rich perilla oil (PO) and fish oil (FO) high fat diet intervention against the synthesis of hepatic high-density lipoprotein cholesterol (HDL-c) in obesity-insulin resistance model rats. Methods In the modeling period, the male SD rats were randomly divided into 2 groups. The rats in the high fat (HF) group were given a high fat pure diet containing 20.62 % lard. In the intervention period, the model rats were intervened with purified high-fat diets rich in PO or FO, containing same energy content with high fat pure diet in HF. After the intervention, the protein and mRNA expressions status of the key genes involved in synthesis of hepatic HDL-c were measured for further analytic comparison. Results The obesity-insulin resistance model rats were characterized by surprisingly high levels of serum triglyceride (TG) and increased body weight (P < 0.05, each). After the intervention, there were no apparent changes in the serum HDL-c and total cholesterol (TCH). In addition, the FO could up-regulate the hepatic adenosine triphosphate (ATP) binding cassette transporter A1 (ABCA1) mRNA (P < 0.01) and protein expressions, as well as increase the level of serum apolipoprotein A-1 (apoA-1) (P < 0.0001), and elevate the hepatic apoA-1mRNA expression (P < 0.01). Different from FO, the PO specifically elevated the hepatic ABCA1mRNA expression (P < 0.01). Conclusions The FO high fat diets promoted the synthesis of HDL-c in the obesity-insulin resistance rats.
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Affiliation(s)
- Xianxing Xie
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Tao Zhang
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Shuang Zhao
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Wei Li
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Lanzhi Ma
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Ming Ding
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China
| | - Yuan Liu
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing, 100071, China.
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da Luz MHM, Glezer I, Xavier AM, da Silva MAP, Pino JMV, Zamith TP, Vieira TF, Antonio BB, Antunes HKM, Martins VR, Lee KS. Expression of Tyrosine Hydroxylase is Negatively Regulated Via Prion Protein. Neurochem Res 2016; 41:1691-9. [DOI: 10.1007/s11064-016-1885-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/26/2016] [Accepted: 03/08/2016] [Indexed: 12/31/2022]
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50
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Fuma S, Shimazawa M, Imamura T, Kanno Y, Takano N, Tsuruma K, Hara H. Neuroprotective Effect of Ocular Hypotensive Drugs: Latanoprost/Timolol in Combination Are More Effective than Each as Monotherapy in RGC-5. Biol Pharm Bull 2016; 39:192-8. [DOI: 10.1248/bpb.b15-00584] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Shinichiro Fuma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Tomoyo Imamura
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Yusuke Kanno
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Norihito Takano
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University
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