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Cagnetta R, Lacaille JC, Sonenberg N. Exploration of new space elicits phosphorylation of GluA1(Ser831) and S6K and expression of Arc in the hippocampus in vivo as in long-term potentiation. Mol Brain 2024; 17:35. [PMID: 38858726 PMCID: PMC11165848 DOI: 10.1186/s13041-024-01100-x] [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: 01/17/2024] [Accepted: 05/14/2024] [Indexed: 06/12/2024] Open
Abstract
The brain responds to experience through modulation of synaptic transmission, that is synaptic plasticity. An increase in the strength of synaptic transmission is manifested as long-term potentiation (LTP), while a decrease in the strength of synaptic transmission is expressed as long-term depression (LTD). Most of the studies of synaptic plasticity have been carried out by induction via electrophysiological stimulation. It is largely unknown in which behavioural tasks such synaptic plasticity occurs. Moreover, some stimuli can induce both LTP and LTD, thus making it difficult to separately study the different forms of synaptic plasticity. Two studies have shown that an aversive memory task - inhibitory avoidance learning and contextual fear conditioning - physiologically and selectively induce LTP and an LTP-like molecular change, respectively, in the hippocampus in vivo. Here, we show that a non-aversive behavioural task - exploration of new space - physiologically and selectively elicits a biochemical change in the hippocampus that is a hallmark of LTP. Specifically, we found that exploration of new space induces an increase in the phosphorylation of GluA1(Ser831), without affecting the phosphorylation of GluA1(Ser845), which are biomarkers of early-LTP and not NMDAR-mediated LTD. We also show that exploration of new space engenders the phosphorylation of the translational regulator S6K and the expression of Arc, which are features of electrophysiologically-induced late-LTP in the hippocampus. Therefore, our results show that exploration of new space is a novel non-aversive behavioural paradigm that elicits molecular changes in vivo that are analogous to those occurring during early- and late-LTP, but not during NMDAR-mediated LTD.
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Affiliation(s)
- Roberta Cagnetta
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada.
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research On Brain and Learning, Research Group On Neural Signaling and Circuitry, University of Montreal, Montreal, QC, H3T1J4, Canada
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada.
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Jin Y, Yuan H, Mehta I, Ezenwa O, Morel PA. Alternatively Spliced Variants of Murine CD247 Influence T Cell Development and Activation, Revealing the Importance of the CD3ζ C-Terminal Region. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:541-550. [PMID: 38117282 PMCID: PMC10872740 DOI: 10.4049/jimmunol.2300511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023]
Abstract
CD247, also known as CD3ζ, is a crucial signaling molecule that transduces signals delivered by TCR through its three ITAMs. CD3ζ is required for successful thymocyte development. Three additional alternatively spliced variants of murine CD247 have been described, that is, CD3ι, CD3θ, and CD3η, that differ from CD3ζ in the C terminus such that the third ITAM is lost. Previous studies demonstrated defects in T cell development in mice expressing CD3η, but the TCR signaling pathways affected by CD3η and the impacts of the CD3ι and CD3θ on T cell development were not explored. In this study, we used a retrovirus-mediated gene transfer technique to express these three isoforms individually and examined the roles of them on T cell development and activation. Rag1-/- mice reconstituted with CD3θ-expressing bone marrow failed to develop mature T cells. CD3ι-expressing T cells exhibited similar development and activation as cells expressing CD3ζ. In contrast, thymic development was severely impaired in CD3η-reconstituted mice. Single-positive but not double-positive CD3η-expressing thymocytes had reduced TCR expression, and CD5 expression was decreased at the double-positive stage, suggesting a defect in positive selection. Peripheral CD3η-expressing T cells had expanded CD44hi populations and upregulation of exhaustion markers seen by flow cytometry and RNA sequencing analysis. Analysis of early signaling events demonstrated significantly reduced activation of both the PLCγ1 and Akt/mTOR signaling pathways. There was also a reduction in the frequency of activation of CD3η-expressing T cells. These studies reveal the importance of the CD3ζ C-terminal region in T cell development and activation.
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Affiliation(s)
- Ye Jin
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Huijuan Yuan
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh PA
| | - Isha Mehta
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Ogechukwu Ezenwa
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Penelope A Morel
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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Rahman M, Nguyen TM, Lee GJ, Kim B, Park MK, Lee CH. Unraveling the Role of Ras Homolog Enriched in Brain (Rheb1 and Rheb2): Bridging Neuronal Dynamics and Cancer Pathogenesis through Mechanistic Target of Rapamycin Signaling. Int J Mol Sci 2024; 25:1489. [PMID: 38338768 PMCID: PMC10855792 DOI: 10.3390/ijms25031489] [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: 12/15/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 02/12/2024] Open
Abstract
Ras homolog enriched in brain (Rheb1 and Rheb2), small GTPases, play a crucial role in regulating neuronal activity and have gained attention for their implications in cancer development, particularly in breast cancer. This study delves into the intricate connection between the multifaceted functions of Rheb1 in neurons and cancer, with a specific focus on the mTOR pathway. It aims to elucidate Rheb1's involvement in pivotal cellular processes such as proliferation, apoptosis resistance, migration, invasion, metastasis, and inflammatory responses while acknowledging that Rheb2 has not been extensively studied. Despite the recognized associations, a comprehensive understanding of the intricate interplay between Rheb1 and Rheb2 and their roles in both nerve and cancer remains elusive. This review consolidates current knowledge regarding the impact of Rheb1 on cancer hallmarks and explores the potential of Rheb1 as a therapeutic target in cancer treatment. It emphasizes the necessity for a deeper comprehension of the molecular mechanisms underlying Rheb1-mediated oncogenic processes, underscoring the existing gaps in our understanding. Additionally, the review highlights the exploration of Rheb1 inhibitors as a promising avenue for cancer therapy. By shedding light on the complicated roles between Rheb1/Rheb2 and cancer, this study provides valuable insights to the scientific community. These insights are instrumental in guiding the identification of novel targets and advancing the development of effective therapeutic strategies for treating cancer.
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Affiliation(s)
- Mostafizur Rahman
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Tuan Minh Nguyen
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Gi Jeong Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Boram Kim
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Mi Kyung Park
- Department of BioHealthcare, Hwasung Medi-Science University, Hwaseong-si 18274, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
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Duarte-Guterman P, Richard JE, Lieblich SE, Eid RS, Lamers Y, Galea LAM. Cellular and molecular signatures of motherhood in the adult and ageing rat brain. Open Biol 2023; 13:230217. [PMID: 37989220 PMCID: PMC10681025 DOI: 10.1098/rsob.230217] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/23/2023] [Indexed: 11/23/2023] Open
Abstract
Pregnancy is marked by robust changes, including brain changes to volume, structure, connectivity and neuroplasticity. Although some brain changes are restricted to pregnancy and the postpartum, others are long-lasting. Few studies have examined possible mechanisms of these changes or the effects of multiple pregnancies. We characterized various cellular and molecular signatures of parity (nulliparous, primiparous, biparous) in the rat hippocampus. We investigated density of neural stems cells (Sox2), microglia (Iba-1) and levels of a synaptic protein (PSD-95), cell signalling pathways, neuroinflammation, and the tryptophan-kynurenine (TRP-KYN) pathway, one week after weaning their pups from the last pregnancy (age of dam: seven months) and in middle-age (age of dam: 13 months). Parity increased PSD-95 levels in both age groups and prevented the age-related decrease in neural stem cell density observed in nulliparous rats. Biparity increased cell signalling phosphoproteins (pp70S6K, S6RP) and number of microglia in the dentate gyrus, regardless of age. Parity resulted in transient changes to the TRP-KYN system. Thus, previous parity has lasting effects on synaptic plasticity with fewer lasting effects on inflammation and cell signalling phosphoproteins in the whole hippocampus.
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Affiliation(s)
- P. Duarte-Guterman
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
| | - J. E. Richard
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - S. E. Lieblich
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
| | - R. S. Eid
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Y. Lamers
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - L. A. M. Galea
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain health, University of British Columbia, Vancouver, British Columbia, Canada
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Eyford BA, Lazarczyk MJ, Choi KB, Varghese M, Arora H, Kari S, Munro L, Pfeifer CG, Sowa A, Dickstein DR, Dickstein DL, Jefferies WA. Outside-in signaling through the major histocompatibility complex class-I cytoplasmic tail modulates glutamate receptor expression in neurons. Sci Rep 2023; 13:13079. [PMID: 37567897 PMCID: PMC10421907 DOI: 10.1038/s41598-023-38663-z] [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: 03/16/2023] [Accepted: 07/12/2023] [Indexed: 08/13/2023] Open
Abstract
The interplay between AMPA-type glutamate receptors (AMPARs) and major histocompatibility complex class I (MHC-I) proteins in regulating synaptic signaling is a crucial aspect of central nervous system (CNS) function. In this study, we investigate the significance of the cytoplasmic tail of MHC-I in synaptic signaling within the CNS and its impact on the modulation of synaptic glutamate receptor expression. Specifically, we focus on the Y321 to F substitution (Y321F) within the conserved cytoplasmic tyrosine YXXΦ motif, known for its dual role in endocytosis and cellular signaling of MHC-I. Our findings reveal that the Y321F substitution influences the expression of AMPAR subunits GluA2/3 and leads to alterations in the phosphorylation of key kinases, including Fyn, Lyn, p38, ERK1/2, JNK1/2/3, and p70 S6 kinase. These data illuminate the crucial role of MHC-I in AMPAR function and present a novel mechanism by which MHC-I integrates extracellular cues to modulate synaptic plasticity in neurons, which ultimately underpins learning and memory.
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Affiliation(s)
- Brett A Eyford
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada
| | - Maciej J Lazarczyk
- Division of Institutional Measures, Department of Medical Direction and Quality, University Hospitals of Geneva, Geneva, Switzerland
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY, 10029, USA
| | - Kyung Bok Choi
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada
- Department of Microbiology and Immunology, University of British Columbia, 1365-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Merina Varghese
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY, 10029, USA
| | - Hitesh Arora
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
| | - Suresh Kari
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada
- Department of Microbiology and Immunology, University of British Columbia, 1365-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Lonna Munro
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada
- Department of Microbiology and Immunology, University of British Columbia, 1365-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Cheryl G Pfeifer
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada
- Department of Microbiology and Immunology, University of British Columbia, 1365-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
- Department of Medical Genetics, University of British Columbia, 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Allison Sowa
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY, 10029, USA
| | - Daniel R Dickstein
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY, 10029, USA
| | - Dara L Dickstein
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY, 10029, USA.
- Department of Pathology, Uniformed Services University of Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
- The Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), 6720A Rockledge Drive, Bethesda, MD, 20817, USA.
| | - Wilfred A Jefferies
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- The Vancouver Prostate Centre, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada.
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada.
- Department of Microbiology and Immunology, University of British Columbia, 1365-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada.
- Department of Medical Genetics, University of British Columbia, 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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Liu J, Zhou S, Wang Y, Liu J, Sun S, Sun Y, Xu P, Xu X, Zhu B, Wu H. ZeXieYin Formula alleviates TMAO-induced cognitive impairment by restoring synaptic plasticity damage. JOURNAL OF ETHNOPHARMACOLOGY 2023; 314:116604. [PMID: 37178985 DOI: 10.1016/j.jep.2023.116604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 04/29/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Treating cognitive impairment is a challenging and necessary research topic. ZeXieYin Formula (ZXYF), is a traditional herbal formula documented in the book of HuangDiNeiJing. Our previous studies demonstrated the ameliorative effects of ZXYF on atherosclerosis by reducing the plasma trimethylamine oxide (TMAO) level. TMAO is a metabolite of gut microorganisms, our recent research found that the increasing level of TMAO may have adverse effects on cognitive functions. AIM OF THE STUDY Our study mainly focused on the therapeutic effects of ZXYF on TMAO-induced cognitive impairment in mice and explored its underlying mechanism. MATERIALS AND METHODS After the TMAO-induced cognitive impairment mice models were established, we applied behavioral tests to estimate the learning and memory ability of the ZXYF intervention mice. Liquid chromatography-mass spectrometry (LC-MS) was used to quantify the TMAO levels in plasma and the brain. The effects of ZXYF on the hippocampal synaptic structure and the neurons were observed by transmission electron microscopy (TEM) and Nissl staining. In addition, western-blotting (WB) and immunohistochemical (IHC) staining were used to detect the level of related proteins in the synaptic structure and further verify the changes in synaptic plasticity and the mTOR pathway after ZXYF administration. RESULTS Behavioral tests showed that the learning and memory ability of mice impaired after a period of TMAO intervention and ZXYF could alleviate these changes. A series of results showed that ZXYF partly restored the damage of hippocampal synapse and neurons in TMAO-induced mice, at the same time, the expression of synapse-related proteins and mTOR pathway-related proteins were significantly regulated compared with the damage caused by TMAO. CONCLUSION ZXYF could alleviate TMAO-induced cognitive impairment by improving synaptic function, reducing neuronal damage, regulating synapse-associated proteins, and regulating the mTOR signaling pathway.
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Affiliation(s)
- Jing Liu
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Shihan Zhou
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Yanqing Wang
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Jinling Liu
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - SuPing Sun
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Yan Sun
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Ping Xu
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China
| | - Xu Xu
- Nantong TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Nantong, Jiangsu, 226001, China
| | - Boran Zhu
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China.
| | - Haoxin Wu
- College of Traditional Chinese Medicine and College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China; Key Laboratory of Integrative Biomedicine for Brain Diseases, College of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, China.
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7
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Nicoletti F, Di Menna L, Iacovelli L, Orlando R, Zuena AR, Conn PJ, Dogra S, Joffe ME. GPCR interactions involving metabotropic glutamate receptors and their relevance to the pathophysiology and treatment of CNS disorders. Neuropharmacology 2023; 235:109569. [PMID: 37142158 DOI: 10.1016/j.neuropharm.2023.109569] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/06/2023]
Abstract
Cellular responses to metabotropic glutamate (mGlu) receptor activation are shaped by mechanisms of receptor-receptor interaction. mGlu receptor subtypes form homodimers, intra- or inter-group heterodimers, and heteromeric complexes with other G protein-coupled receptors (GPCRs). In addition, mGlu receptors may functionally interact with other receptors through the βγ subunits released from G proteins in response to receptor activation or other mechanisms. Here, we discuss the interactions between (i) mGlu1 and GABAB receptors in cerebellar Purkinje cells; (ii) mGlu2 and 5-HT2Aserotonergic receptors in the prefrontal cortex; (iii) mGlu5 and A2A receptors or mGlu5 and D1 dopamine receptors in medium spiny projection neurons of the indirect and direct pathways of the basal ganglia motor circuit; (iv) mGlu5 and A2A receptors in relation to the pathophysiology of Alzheimer's disease; and (v) mGlu7 and A1 adenosine or α- or β1 adrenergic receptors. In addition, we describe in detail a novel form of non-heterodimeric interaction between mGlu3 and mGlu5 receptors, which appears to be critically involved in mechanisms of activity-dependent synaptic plasticity in the prefrontal cortex and hippocampus. Finally, we highlight the potential implication of these interactions in the pathophysiology and treatment of cerebellar disorders, schizophrenia, Alzheimer's disease, Parkinson's disease, l-DOPA-induced dyskinesias, stress-related disorders, and cognitive dysfunctions.
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Affiliation(s)
- Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy.
| | | | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Anna Rita Zuena
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy
| | - P Jeffrey Conn
- Department of Pharmacology, Italy; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, USA
| | - Shalini Dogra
- Department of Pharmacology, Italy; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, USA
| | - Max E Joffe
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA
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8
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Tariq K, Cullen E, Getz SA, Conching AK, Goyette AR, Prina ML, Wang W, Li M, Weston MC, Luikart BW. Disruption of mTORC1 rescues neuronal overgrowth and synapse function dysregulated by Pten loss. Cell Rep 2022; 41:111574. [PMID: 36323257 PMCID: PMC9743803 DOI: 10.1016/j.celrep.2022.111574] [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: 03/31/2022] [Revised: 09/06/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a negative regulator of AKT/mTOR signaling pathway. Mutations in PTEN are found in patients with autism, epilepsy, or macrocephaly. In mouse models, Pten loss results in neuronal hypertrophy, hyperexcitability, seizures, and ASD-like behaviors. The underlying molecular mechanisms of these phenotypes are not well delineated. We determined which of the Pten loss-driven aberrations in neuronal form and function are orchestrated by downstream mTOR complex 1 (mTORC1). Rapamycin-mediated inhibition of mTORC1 prevented increase in soma size, migration, spine density, and dendritic overgrowth in Pten knockout dentate gyrus granule neurons. Genetic knockout of Raptor to disrupt mTORC1 complex formation blocked Pten loss-mediated neuronal hypertrophy. Electrophysiological recordings revealed that genetic disruption of mTORC1 rescued Pten loss-mediated increase in excitatory synaptic transmission. We have identified an essential role for mTORC1 in orchestrating Pten loss-driven neuronal hypertrophy and synapse formation.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Erin Cullen
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Stephanie A. Getz
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Andie K.S. Conching
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Andrew R. Goyette
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Mackenzi L. Prina
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Wei Wang
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Meijie Li
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Matthew C. Weston
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA,These authors contributed equally,Correspondence: (M.C.W.), (B.W.L.)
| | - Bryan W. Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA,These authors contributed equally,Lead contact,Correspondence: (M.C.W.), (B.W.L.)
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9
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Sato A, Ikeda K. Genetic and Environmental Contributions to Autism Spectrum Disorder Through Mechanistic Target of Rapamycin. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 2:95-105. [PMID: 36325164 PMCID: PMC9616270 DOI: 10.1016/j.bpsgos.2021.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects an individual’s reciprocal social interaction and communication ability. Numerous genetic and environmental conditions are associated with ASD, including tuberous sclerosis complex, phosphatase and tensin homolog hamartoma tumor syndrome, fragile X syndrome, and neurofibromatosis 1. The pathogenic molecular mechanisms of these diseases are integrated into the hyperactivation of mTORC1 (mechanistic target of rapamycin complex 1). Rodent models of these diseases have shown high mTORC1 activity in the brain and ASD-related behavioral deficits, which were reversed by the mTORC1 inhibitor rapamycin. Environmental stress can also affect this signaling pathway. In utero exposure to valproate caused ASD in offspring and enhanced mTORC1 activity in the brain, which was sensitive to mTORC1 inhibition. mTORC1 is a signaling hub for diverse cellular functions, including protein synthesis, through the phosphorylation of its targets, such as ribosomal protein S6 kinases. Metabotropic glutamate receptor 5–mediated synaptic function is also affected by the dysregulation of mTORC1 activity, such as in fragile X syndrome and tuberous sclerosis complex. Reversing these downstream changes that are associated with mTORC1 activation normalizes behavioral defects in rodents. Despite abundant preclinical evidence, few clinical studies have investigated the treatment of ASD and cognitive deficits. Therapeutics other than mTORC1 inhibitors failed to show efficacy in fragile X syndrome and neurofibromatosis 1. mTORC1 inhibitors have been tested mainly in tuberous sclerosis complex, and their effects on ASD and neuropsychological deficits are promising. mTORC1 is a promising target for the pharmacological treatment of ASD associated with mTORC1 activation.
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10
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Bryan de la Peña J, Kunder N, Lou TF, Chase R, Stanowick A, Barragan-Iglesias P, Pancrazio JJ, Campbell ZT. A Role for Translational Regulation by S6 Kinase and a Downstream Target in Inflammatory Pain. Br J Pharmacol 2021; 178:4675-4690. [PMID: 34355805 DOI: 10.1111/bph.15646] [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: 05/09/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Translational controls pervade neurobiology. Nociceptors play an integral role in the detection and propagation of pain signals. Nociceptors can undergo persistent changes in their intrinsic excitability. Pharmacologic disruption of nascent protein synthesis diminishes acute and chronic forms of pain-associated behaviors. Yet, the targets of translational controls that facilitate plasticity in nociceptors are unclear. EXPERIMENTAL APPROACH We used ribosome profiling to probe the translational landscape in DRG neurons after treatment of the inflammatory mediators NGF and IL-6. We validated the expression dynamics of c-Fos using immunoblotting and immunohistochemistry. Given that inflammation is known to stimulate mTOR signaling, we reasoned that downstream factors (e.g., ribosomal protein S6 kinase 1, S6K1) might control c-Fos levels. We utilized small-molecule inhibitors of S6K1 (DG2) or c-Fos (T-5224) to probe their effects on nociceptor activity in vitro using multi-electrode arrays (MEAs) and pain behavior in vivo using a hyperalgesic priming model. KEY RESULTS We demonstrate that c-Fos is expressed in sensory neurons. Inflammatory mediators that promote pain in both humans and rodents promote c-Fos translation. We demonstrate that the mTOR effector S6K1 is essential for c-Fos biosynthesis. Inhibition of S6K1 or c-Fos with small molecules diminish mechanical and thermal hypersensitivity in response to inflammatory cues. Additionally, both inhibitors reduce evoked nociceptor activity. CONCLUSION Our data reveal a novel role of S6K1 in modulating rapid response to inflammatory mediators, with c-Fos being one key downstream target. Targeting the S6 kinase pathway or c-Fos is an exciting new avenue for pain-modulating compounds.
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Affiliation(s)
- June Bryan de la Peña
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Nikesh Kunder
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Tzu-Fang Lou
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Rebecca Chase
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Alexander Stanowick
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Paulino Barragan-Iglesias
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA.,Department of Physiology and Pharmacology, Center for Basic Sciences, Autonomous University of Aguascalientes, Aguascalientes, Mexico
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA.,Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Zachary T Campbell
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA.,Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA.,Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
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11
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Beydoun S, Fardous AM, Saruna MM, Beydoun AG, Sorge JA, Ma H, Aoun G, Unnikrishnan A, Cabelof DC, Heydari AR. Succinylsulfathiazole modulates the mTOR signaling pathway in the liver of c57BL/6 mice via a folate independent mechanism. Exp Gerontol 2021; 150:111387. [PMID: 33957263 PMCID: PMC8165018 DOI: 10.1016/j.exger.2021.111387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/25/2021] [Accepted: 04/28/2021] [Indexed: 01/27/2023]
Abstract
Researchers studying the effect of folate restriction on rodents have resorted to the use of the antibiotic succinylsulfathiazole (SST) in the folate depleted diet to induce a folate deficient status. SST has been used extensively in rodent studies since the 1940s. Its localized effect on the gut bacteria as well as its effectiveness in reducing folate producing species is well documented. The possible overlap between the pathways affected by folate depletion and SST could potentially produce a confounding variable in such studies. In our novel study, we analyzed the effect of SST on folate levels in c57Bl/6 male mice fed folate supplemented and deficient diets. We did not observe any significant difference on growth and weight gain at 21 weeks. SST did not significantly affect folate levels in the plasma, liver and colon tissues; however, it did alter energy metabolism and expression of key genes in the mTOR signaling pathway in the liver. This research sheds light on a possible confounding element when using SST to study folate depletion due to the potential overlap with multiple critical pathways such as mTOR. SUMMARY: The antibiotic succinylsulfathiazole (SST) is used to reduce folate producing bacteria in rodent folate depletion studies. SST can modulate critical energy and nutrient sensing pathways converging onto mTOR signaling, and potentially confounding cancer studies.
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Affiliation(s)
- Safa Beydoun
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ali M Fardous
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Michael M Saruna
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Ali G Beydoun
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Johnathan A Sorge
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Hongzhi Ma
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Ghada Aoun
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA
| | - Archana Unnikrishnan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health and Science Center, OK 73104, USA
| | - Diane C Cabelof
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA; Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI 48202, USA
| | - Ahmad R Heydari
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA; Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI 48202, USA.
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12
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Burillo J, Marqués P, Jiménez B, González-Blanco C, Benito M, Guillén C. Insulin Resistance and Diabetes Mellitus in Alzheimer's Disease. Cells 2021; 10:1236. [PMID: 34069890 PMCID: PMC8157600 DOI: 10.3390/cells10051236] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Type 2 diabetes mellitus is a progressive disease that is characterized by the appearance of insulin resistance. The term insulin resistance is very wide and could affect different proteins involved in insulin signaling, as well as other mechanisms. In this review, we have analyzed the main molecular mechanisms that could be involved in the connection between type 2 diabetes and neurodegeneration, in general, and more specifically with the appearance of Alzheimer's disease. We have studied, in more detail, the different processes involved, such as inflammation, endoplasmic reticulum stress, autophagy, and mitochondrial dysfunction.
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Affiliation(s)
- Jesús Burillo
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Patricia Marqués
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Beatriz Jiménez
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Carlos González-Blanco
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Manuel Benito
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Carlos Guillén
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
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13
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Inhibition of mTOR signaling by genetic removal of p70 S6 kinase 1 increases anxiety-like behavior in mice. Transl Psychiatry 2021; 11:165. [PMID: 33723223 PMCID: PMC7960700 DOI: 10.1038/s41398-020-01187-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/31/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a ubiquitously expressed kinase that acts through two complexes, mTORC1 and mTORC2, to regulate protein homeostasis, as well as long lasting forms of synaptic and behavioral plasticity. Alteration of the mTOR pathway is classically involved in neurodegenerative disorders, and it has been linked to dysregulation of cognitive functions and affective states. However, information concerning the specific involvement of the p70 S6 kinase 1 (S6K1), a downstream target of the mTORC1 pathway, in learning and memory processes and in the regulation of affective states remains scant. To fill this gap, we exposed adult male mice lacking S6K1 to a battery of behavioral tests aimed at measuring their learning and memory capabilities by evaluating reference memory and flexibility with the Morris water maze, and associative memory using the contextual fear conditioning task. We also studied their anxiety-like and depression-like behaviors by, respectively, performing elevated plus maze, open field, light-dark emergence tests, and sucrose preference and forced swim tests. We found that deleting S6K1 leads to a robust anxious phenotype concomitant with associative learning deficits; these symptoms are associated with a reduction of adult neurogenesis and neuronal atrophy in the hippocampus. Collectively, these results provide grounds for the understanding of anxiety reports after treatments with mTOR inhibitors and will be critical for developing novel compounds targeting anxiety.
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14
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Uddin MS, Rahman MA, Kabir MT, Behl T, Mathew B, Perveen A, Barreto GE, Bin-Jumah MN, Abdel-Daim MM, Ashraf GM. Multifarious roles of mTOR signaling in cognitive aging and cerebrovascular dysfunction of Alzheimer's disease. IUBMB Life 2020; 72:1843-1855. [PMID: 32472959 DOI: 10.1002/iub.2324] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/10/2020] [Accepted: 05/13/2020] [Indexed: 12/19/2022]
Abstract
Age-related cognitive failure is a main devastating incident affecting even healthy people. Alzheimer's disease (AD) is the utmost common form of dementia among the geriatric community. In the pathogenesis of AD, cerebrovascular dysfunction is revealed before the beginning of the cognitive decline. Mounting proof shows a precarious impact of cerebrovascular dysregulation in the development of AD pathology. Recent studies document that the mammalian target of rapamycin (mTOR) acts as a crucial effector of cerebrovascular dysregulation in AD. The mTOR contributes to brain vascular dysfunction and subsequence cerebral blood flow deficits as well as cognitive impairment. Furthermore, mTOR causes the blood-brain barrier (BBB) breakdown in AD models. Inhibition of mTOR hyperactivity protects the BBB integrity in AD. Furthermore, mTOR drives cognitive defect and cerebrovascular dysfunction, which are greatly prevalent in AD, but the central molecular mechanisms underlying these alterations are obscure. This review represents the crucial and current research findings regarding the role of mTOR signaling in cognitive aging and cerebrovascular dysfunction in the pathogenesis of AD.
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Affiliation(s)
- Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh.,Pharmakon Neuroscience Research Network, Dhaka, Bangladesh
| | - Md Ataur Rahman
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | | | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Patiala, India
| | - Bijo Mathew
- Division of Drug Design and Medicinal Chemistry Research Lab, Department of Pharmaceutical Chemistry, Ahalia School of Pharmacy, Palakkad, India
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland.,Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - May N Bin-Jumah
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.,Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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15
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Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that causes intellectual disability. It is a leading known genetic cause of autism. In addition to cognitive, social, and communication deficits, humans with FXS demonstrate abnormal sensory processing including sensory hypersensitivity. Sensory hypersensitivity commonly manifests as auditory, tactile, or visual defensiveness or avoidance. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity, impaired habituation to repeated sounds, and reduced auditory attention in humans with FXS. Children with FXS also exhibit significant visuospatial impairments. Studies in infants and toddlers with FXS have documented impairments in processing texture-defined motion stimuli, temporal flicker, perceiving ordinal numerical sequence, and the ability to maintain the identity of dynamic object information during occlusion. Consistent with the observations in humans with FXS, fragile X mental retardation 1 ( Fmr1) gene knockout (KO) rodent models of FXS also show seizures, abnormal visual-evoked responses, auditory hypersensitivity, and abnormal processing at multiple levels of the auditory system, including altered acoustic startle responses. Among other sensory symptoms, individuals with FXS exhibit tactile defensiveness. Fmr1 KO mice also show impaired encoding of tactile stimulation frequency and larger size of receptive fields in the somatosensory cortex. Since sensory deficits are relatively more tractable from circuit mechanisms and developmental perspectives than more complex social behaviors, the focus of this review is on clinical, functional, and structural studies that outline the auditory, visual, and somatosensory processing deficits in FXS. The similarities in sensory phenotypes between humans with FXS and animal models suggest a likely conservation of basic sensory processing circuits across species and may provide a translational platform to not just develop biomarkers but also to understand underlying mechanisms. We argue that preclinical studies in animal models of FXS can facilitate the ongoing search for new therapeutic approaches in FXS by understanding mechanisms of basic sensory processing circuits and behaviors that are conserved across species.
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Affiliation(s)
- Maham Rais
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA
| | - Devin K Binder
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA
| | - Khaleel A Razak
- 2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA.,4 Psychology Department, University of California Riverside, CA, USA
| | - Iryna M Ethell
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA
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16
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Fricano-Kugler CJ, Getz SA, Williams MR, Zurawel AA, DeSpenza T, Frazel PW, Li M, O’Malley AJ, Moen EL, Luikart BW. Nuclear Excluded Autism-Associated Phosphatase and Tensin Homolog Mutations Dysregulate Neuronal Growth. Biol Psychiatry 2018; 84:265-277. [PMID: 29373119 PMCID: PMC5984669 DOI: 10.1016/j.biopsych.2017.11.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/01/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Phosphatase and tensin homolog (PTEN) negatively regulates downstream protein kinase B signaling, resulting in decreased cellular growth and proliferation. PTEN is mutated in a subset of children with autism spectrum disorder (ASD); however, the mechanism by which specific point mutations alter PTEN function is largely unknown. Here, we assessed how ASD-associated single-nucleotide variations in PTEN (ASD-PTEN) affect function. METHODS We used viral-mediated molecular substitution of human PTEN into Pten knockout mouse neurons and assessed neuronal morphology to determine the functional impact of ASD-PTEN. We employed molecular cloning to examine how PTEN's stability, subcellular localization, and catalytic activity affect neuronal growth. RESULTS We identified a set of ASD-PTEN mutations displaying altered lipid phosphatase function and subcellular localization. We demonstrated that wild-type PTEN can rescue the neuronal hypertrophy, while PTEN H93R, F241S, D252G, W274L, N276S, and D326N failed to rescue this hypertrophy. A subset of these mutations lacked nuclear localization, prompting us to examine the role of nuclear PTEN in regulating neuronal growth. We found that nuclear PTEN alone is sufficient to regulate soma size. Furthermore, forced localization of the D252G and W274L mutations into the nucleus partially restores regulation of soma size. CONCLUSIONS ASD-PTEN mutations display decreased stability, catalytic activity, and/or altered subcellular localization. Mutations lacking nuclear localization uncover a novel mechanism whereby lipid phosphatase activity in the nucleus can regulate mammalian target of rapamycin signaling and neuronal growth.
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Affiliation(s)
- Catherine J. Fricano-Kugler
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Stephanie A. Getz
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Michael R. Williams
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Ashley A. Zurawel
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Tyrone DeSpenza
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Paul W. Frazel
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Meijie Li
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756
| | - Alistair J. O’Malley
- The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA,Department of Biomedical Data Science, The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Erika L. Moen
- The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Bryan W. Luikart
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth College, Lebanon, New Hampshire 03756,Corresponding Author-
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17
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Huang X, Wu H, Jiang R, Sun G, Shen J, Ma M, Ma C, Zhang S, Huang Z, Wu Q, Chen G, Tao W. The antidepressant effects of ɑ-tocopherol are related to activation of autophagy via the AMPK/mTOR pathway. Eur J Pharmacol 2018; 833:1-7. [DOI: 10.1016/j.ejphar.2018.05.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/28/2018] [Accepted: 05/17/2018] [Indexed: 12/25/2022]
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18
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Abstract
The mammalian/mechanistic target of rapamycin (mTOR) kinase resides at the crux of an intracellular signaling network that controls fundamental biological processes. Dysregulation of mTOR signaling is linked to neurological and psychiatric diseases. However, the physiological functions of mTOR signaling in the adult brain are not fully understood. In the current study, we discovered that mTOR in vasoactive intestinal peptide (VIP) neurons plays a key role in regulating neurophysiology in the brain circadian clock and the olfactory system. The conditional mTOR knockout mouse will be a useful model for future investigations of mTOR and/or VIP. Mammalian/mechanistic target of rapamycin (mTOR) signaling controls cell growth, proliferation, and metabolism in dividing cells. Less is known regarding its function in postmitotic neurons in the adult brain. Here we created a conditional mTOR knockout mouse model to address this question. Using the Cre-LoxP system, the mTOR gene was specifically knocked out in cells expressing Vip (vasoactive intestinal peptide), which represent a major population of interneurons widely distributed in the neocortex, suprachiasmatic nucleus (SCN), olfactory bulb (OB), and other brain regions. Using a combination of biochemical, behavioral, and imaging approaches, we found that mice lacking mTOR in VIP neurons displayed erratic circadian behavior and weakened synchronization among cells in the SCN, the master circadian pacemaker in mammals. Furthermore, we have discovered a critical role for mTOR signaling in mediating olfaction. Odor stimulated mTOR activation in the OB, anterior olfactory nucleus, as well as piriform cortex. Odor-evoked c-Fos responses along the olfactory pathway were abolished in mice lacking mTOR in VIP neurons, which is consistent with reduced olfactory sensitivity in these animals. Together, these results demonstrate that mTOR is a key regulator of SCN circadian clock synchrony and olfaction.
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19
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Tréfier A, Pellissier LP, Musnier A, Reiter E, Guillou F, Crépieux P. G Protein-Coupled Receptors As Regulators of Localized Translation: The Forgotten Pathway? Front Endocrinol (Lausanne) 2018; 9:17. [PMID: 29456523 PMCID: PMC5801404 DOI: 10.3389/fendo.2018.00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/15/2018] [Indexed: 12/31/2022] Open
Abstract
G protein-coupled receptors (GPCRs) exert their physiological function by transducing a complex signaling network that coordinates gene expression and dictates the phenotype of highly differentiated cells. Much is known about the gene networks they transcriptionally regulate upon ligand exposure in a process that takes hours before a new protein is synthesized. However, far less is known about GPCR impact on the translational machinery and subsequent mRNA translation, although this gene regulation level alters the cell phenotype in a strikingly different timescale. In fact, mRNA translation is an early response kinetically connected to signaling events, hence it leads to the synthesis of a new protein within minutes following receptor activation. By these means, mRNA translation is responsive to subtle variations of the extracellular environment. In addition, when restricted to cell subcellular compartments, local mRNA translation contributes to cell micro-specialization, as observed in synaptic plasticity or in cell migration. The mechanisms that control where in the cell an mRNA is translated are starting to be deciphered. But how an extracellular signal triggers such local translation still deserves extensive investigations. With the advent of high-throughput data acquisition, it now becomes possible to review the current knowledge on the translatome that some GPCRs regulate, and how this information can be used to explore GPCR-controlled local translation of mRNAs.
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Affiliation(s)
- Aurélie Tréfier
- Biologie et Bioinformatique des Systèmes de Signalisation, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
| | - Lucie P. Pellissier
- Déficit de Récompense, GPCR et sociabilité, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
| | - Astrid Musnier
- Biologie et Bioinformatique des Systèmes de Signalisation, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
| | - Eric Reiter
- Biologie et Bioinformatique des Systèmes de Signalisation, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
| | - Florian Guillou
- Plasticité Génomique et Expression Phénotypique, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
| | - Pascale Crépieux
- Biologie et Bioinformatique des Systèmes de Signalisation, INRA, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais, Tours, France
- IFCE, Nouzilly, France
- *Correspondence: Pascale Crépieux,
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20
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Puighermanal E, Biever A, Pascoli V, Melser S, Pratlong M, Cutando L, Rialle S, Severac D, Boubaker-Vitre J, Meyuhas O, Marsicano G, Lüscher C, Valjent E. Ribosomal Protein S6 Phosphorylation Is Involved in Novelty-Induced Locomotion, Synaptic Plasticity and mRNA Translation. Front Mol Neurosci 2017; 10:419. [PMID: 29311811 PMCID: PMC5742586 DOI: 10.3389/fnmol.2017.00419] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/01/2017] [Indexed: 11/29/2022] Open
Abstract
The phosphorylation of the ribosomal protein S6 (rpS6) is widely used to track neuronal activity. Although it is generally assumed that rpS6 phosphorylation has a stimulatory effect on global protein synthesis in neurons, its exact biological function remains unknown. By using a phospho-deficient rpS6 knockin mouse model, we directly tested the role of phospho-rpS6 in mRNA translation, plasticity and behavior. The analysis of multiple brain areas shows for the first time that, in neurons, phospho-rpS6 is dispensable for overall protein synthesis. Instead, we found that phospho-rpS6 controls the translation of a subset of mRNAs in a specific brain region, the nucleus accumbens (Acb), but not in the dorsal striatum. We further show that rpS6 phospho-mutant mice display altered long-term potentiation (LTP) in the Acb and enhanced novelty-induced locomotion. Collectively, our findings suggest a previously unappreciated role of phospho-rpS6 in the physiology of the Acb, through the translation of a selective subclass of mRNAs, rather than the regulation of general protein synthesis.
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Affiliation(s)
| | - Anne Biever
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Vincent Pascoli
- Department of Basic Neurosciences, Medical Faculty, University of Geneva, Geneva, Switzerland
| | - Su Melser
- INSERM U1215, Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
| | - Marine Pratlong
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Laura Cutando
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Stephanie Rialle
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Dany Severac
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | | | - Oded Meyuhas
- Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Giovanni Marsicano
- INSERM U1215, Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
| | - Christian Lüscher
- Department of Basic Neurosciences, Medical Faculty, University of Geneva, Geneva, Switzerland.,Clinic of Neurology, Department of Clinical Neurosciences, Geneva University Hospital, Geneva, Switzerland
| | - Emmanuel Valjent
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
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21
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Levenga J, Wong H, Milstead RA, Keller BN, LaPlante LE, Hoeffer CA. AKT isoforms have distinct hippocampal expression and roles in synaptic plasticity. eLife 2017; 6:30640. [PMID: 29173281 PMCID: PMC5722612 DOI: 10.7554/elife.30640] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/21/2017] [Indexed: 12/20/2022] Open
Abstract
AKT is a kinase regulating numerous cellular processes in the brain, and mutations in AKT are known to affect brain function. AKT is indirectly implicated in synaptic plasticity, but its direct role has not been studied. Moreover, three highly related AKT isoforms are expressed in the brain, but their individual roles are poorly understood. We find in Mus musculus, each AKT isoform has a unique expression pattern in the hippocampus, with AKT1 and AKT3 primarily in neurons but displaying local differences, while AKT2 is in astrocytes. We also find isoform-specific roles for AKT in multiple paradigms of hippocampal synaptic plasticity in area CA1. AKT1, but not AKT2 or AKT3, is required for L-LTP through regulating activity-induced protein synthesis. Interestingly, AKT activity inhibits mGluR-LTD, with overlapping functions for AKT1 and AKT3. In summary, our studies identify distinct expression patterns and roles in synaptic plasticity for AKT isoforms in the hippocampus.
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Affiliation(s)
- Josien Levenga
- Institute for Behavioral Genetics, University of Colorado-Boulder, Boulder, United States.,Linda Crnic Institute, Aurora, United States
| | - Helen Wong
- Institute for Behavioral Genetics, University of Colorado-Boulder, Boulder, United States
| | - Ryan A Milstead
- Department of Integrative Physiology, University of Colorado-Boulder, Boulder, United States
| | - Bailey N Keller
- Institute for Behavioral Genetics, University of Colorado-Boulder, Boulder, United States
| | - Lauren E LaPlante
- Institute for Behavioral Genetics, University of Colorado-Boulder, Boulder, United States
| | - Charles A Hoeffer
- Institute for Behavioral Genetics, University of Colorado-Boulder, Boulder, United States.,Linda Crnic Institute, Aurora, United States.,Department of Integrative Physiology, University of Colorado-Boulder, Boulder, United States
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22
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Potheraveedu VN, Schöpel M, Stoll R, Heumann R. Rheb in neuronal degeneration, regeneration, and connectivity. Biol Chem 2017; 398:589-606. [PMID: 28212107 DOI: 10.1515/hsz-2016-0312] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 02/02/2017] [Indexed: 01/31/2023]
Abstract
The small GTPase Rheb was originally detected as an immediate early response protein whose expression was induced by NMDA-dependent synaptic activity in the brain. Rheb's activity is highly regulated by its GTPase activating protein (GAP), the tuberous sclerosis complex protein, which stimulates the conversion from the active, GTP-loaded into the inactive, GDP-loaded conformation. Rheb has been established as an evolutionarily conserved molecular switch protein regulating cellular growth, cell volume, cell cycle, autophagy, and amino acid uptake. The subcellular localization of Rheb and its interacting proteins critically regulate its activity and function. In stem cells, constitutive activation of Rheb enhances differentiation at the expense of self-renewal partially explaining the adverse effects of deregulated Rheb in the mammalian brain. In the context of various cellular stress conditions such as oxidative stress, ER-stress, death factor signaling, and cellular aging, Rheb activation surprisingly enhances rather than prevents cellular degeneration. This review addresses cell type- and cell state-specific function(s) of Rheb and mainly focuses on neurons and their surrounding glial cells. Mechanisms will be discussed in the context of therapy that interferes with Rheb's activity using the antibiotic rapamycin or low molecular weight compounds.
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Affiliation(s)
- Veena Nambiar Potheraveedu
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
| | - Miriam Schöpel
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Raphael Stoll
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Rolf Heumann
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
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23
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Niere F, Raab-Graham KF. mTORC1 Is a Local, Postsynaptic Voltage Sensor Regulated by Positive and Negative Feedback Pathways. Front Cell Neurosci 2017; 11:152. [PMID: 28611595 PMCID: PMC5447718 DOI: 10.3389/fncel.2017.00152] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/09/2017] [Indexed: 12/11/2022] Open
Abstract
The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) serves as a regulator of mRNA translation. Recent studies suggest that mTORC1 may also serve as a local, voltage sensor in the postsynaptic region of neurons. Considering biochemical, bioinformatics and imaging data, we hypothesize that the activity state of mTORC1 dynamically regulates local membrane potential by promoting and repressing protein synthesis of select mRNAs. Our hypothesis suggests that mTORC1 uses positive and negative feedback pathways, in a branch-specific manner, to maintain neuronal excitability within an optimal range. In some dendritic branches, mTORC1 activity oscillates between the "On" and "Off" states. We define this as negative feedback. In contrast, positive feedback is defined as the pathway that leads to a prolonged depolarized or hyperpolarized resting membrane potential, whereby mTORC1 activity is constitutively on or off, respectively. We propose that inactivation of mTORC1 increases the expression of voltage-gated potassium alpha (Kv1.1 and 1.2) and beta (Kvβ2) subunits, ensuring that the membrane resets to its resting membrane potential after experiencing increased synaptic activity. In turn, reduced mTORC1 activity increases the protein expression of syntaxin-1A and promotes the surface expression of the ionotropic glutamate receptor N-methyl-D-aspartate (NMDA)-type subunit 1 (GluN1) that facilitates increased calcium entry to turn mTORC1 back on. Under conditions such as learning and memory, mTORC1 activity is required to be high for longer periods of time. Thus, the arm of the pathway that promotes syntaxin-1A and Kv1 protein synthesis will be repressed. Moreover, dendritic branches that have low mTORC1 activity with increased Kv expression would balance dendrites with constitutively high mTORC1 activity, allowing for the neuron to maintain its overall activity level within an ideal operating range. Finally, such a model suggests that recruitment of more positive feedback dendritic branches within a neuron is likely to lead to neurodegenerative disorders.
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Affiliation(s)
- Farr Niere
- Department of Physiology and Pharmacology, Wake Forest School of MedicineWinston-Salem, NC, United States
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest School of MedicineWinston-Salem, NC, United States
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24
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Abelaira HM, Réus GZ, Ignácio ZM, Dos Santos MAB, de Moura AB, Matos D, Demo JP, da Silva JBI, Michels M, Abatti M, Sonai B, Dal Pizzol F, Carvalho AF, Quevedo J. Effects of ketamine administration on mTOR and reticulum stress signaling pathways in the brain after the infusion of rapamycin into prefrontal cortex. J Psychiatr Res 2017; 87:81-87. [PMID: 28017918 DOI: 10.1016/j.jpsychires.2016.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/13/2016] [Accepted: 12/01/2016] [Indexed: 12/23/2022]
Abstract
Recent studies show that activation of the mTOR signaling pathway is required for the rapid antidepressant actions of glutamate N-methyl-D-aspartate (NMDA) receptor antagonists. A relationship between mTOR kinase and the endoplasmic reticulum (ER) stress pathway, also known as the unfolded protein response (UPR) has been shown. We evaluate the effects of ketamine administration on the mTOR signaling pathway and proteins of UPR in the prefrontal cortex (PFC), hippocampus, amygdala and nucleus accumbens, after the inhibiton of mTOR signaling in the PFC. Male adult Wistar rats received pharmacological mTOR inhibitor, rapamycin (0.2 nmol), or vehicle into the PFC and then a single dose of ketamine (15 mg/kg, i.p.). The immunocontent of mTOR, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), eukaryotic elongation factor 2 kinase (eEF2K) homologous protein (CHOP), PKR-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1) - alpha were determined in the brain. The mTOR levels were reduced in the rapamycin group treated with saline and ketamine in the PFC; p4EBP1 levels were reduced in the rapamycin group treated with ketamine in the PFC and nucleus accumbens; the levels of peEF2K were increased in the PFC in the vehicle group treated with ketamine and reduced in the rapamycin group treated with ketamine. The PERK and IRE1-alpha levels were decreased in the PFC in the rapamycin group treated with ketamine. Our results suggest that mTOR signaling inhibition by rapamycin could be involved, at least in part, with the mechanism of action of ketamine; and the ketamine antidepressant on ER stress pathway could be also mediated by mTOR signaling pathway in certain brain structures.
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Affiliation(s)
- Helena M Abelaira
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Gislaine Z Réus
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil.
| | - Zuleide M Ignácio
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Maria Augusta B Dos Santos
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Airam B de Moura
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Danyela Matos
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Júlia P Demo
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Júlia B I da Silva
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Monique Michels
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Mariane Abatti
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Beatriz Sonai
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Felipe Dal Pizzol
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - André F Carvalho
- Translational Psychiatry Research Group and Department of Clinical Medicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
| | - João Quevedo
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil; Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Neuroscience Graduate Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA
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25
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Di Domenico F, Barone E, Perluigi M, Butterfield DA. The Triangle of Death in Alzheimer's Disease Brain: The Aberrant Cross-Talk Among Energy Metabolism, Mammalian Target of Rapamycin Signaling, and Protein Homeostasis Revealed by Redox Proteomics. Antioxid Redox Signal 2017; 26:364-387. [PMID: 27626216 DOI: 10.1089/ars.2016.6759] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SIGNIFICANCE Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder and represents one of the most disabling conditions. AD shares many features in common with systemic insulin resistance diseases, suggesting that it can be considered as a metabolic disease, characterized by reduced insulin-stimulated growth and survival signaling, increased oxidative stress (OS), proinflammatory cytokine activation, mitochondrial dysfunction, impaired energy metabolism, and altered protein homeostasis. Recent Advances: Reduced glucose utilization and energy metabolism in AD have been associated with the buildup of amyloid-β peptide and hyperphosphorylated tau, increased OS, and the accumulation of unfolded/misfolded proteins. Mammalian target of rapamycin (mTOR), which is aberrantly activated in AD since early stages, plays a key role during AD neurodegeneration by, on one side, inhibiting insulin signaling as a negative feedback mechanism and, on the other side, regulating protein homeostasis (synthesis/clearance). CRITICAL ISSUES It is likely that the concomitant and mutual alterations of energy metabolism-mTOR signaling-protein homeostasis might represent a self-sustaining triangle of harmful events that trigger the degeneration and death of neurons and the development and progression of AD. Intriguingly, the altered cross-talk between the components of such a triangle of death, beyond altering the redox homeostasis of the neuron, is further exacerbated by increased levels of OS that target and impair key components of the pathways involved. Redox proteomic studies in human samples and animal models of AD-like dementia led to identification of oxidatively modified components of the pathways composing the triangle of death, therefore revealing the crucial role of OS in fueling this aberrant vicious cycle. FUTURE DIRECTIONS The identification of compounds able to restore the function of the pathways targeted by oxidative damage might represent a valuable therapeutic approach to slow or delay AD. Antioxid. Redox Signal. 26, 364-387.
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Affiliation(s)
- Fabio Di Domenico
- 1 Department of Biochemical Sciences, Sapienza University of Rome , Rome, Italy
| | - Eugenio Barone
- 1 Department of Biochemical Sciences, Sapienza University of Rome , Rome, Italy .,2 Facultad de Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile , Santiago, Chile
| | - Marzia Perluigi
- 1 Department of Biochemical Sciences, Sapienza University of Rome , Rome, Italy
| | - D Allan Butterfield
- 3 Department of Chemistry, Sanders-Brown Center of Aging, University of Kentucky , Lexington, Kentucky
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26
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Zhu G, Briz V, Seinfeld J, Liu Y, Bi X, Baudry M. Calpain-1 deletion impairs mGluR-dependent LTD and fear memory extinction. Sci Rep 2017; 7:42788. [PMID: 28202907 PMCID: PMC5311935 DOI: 10.1038/srep42788] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 01/17/2017] [Indexed: 01/02/2023] Open
Abstract
Recent studies indicate that calpain-1 is required for the induction of long-term potentiation (LTP) elicited by theta-burst stimulation in field CA1 of hippocampus. Here we determined the contribution of calpain-1 in another type of synaptic plasticity, the long-term depression (LTD) elicited by activation of type-I metabotropic glutamate receptors (mGluR-LTD). mGluR-LTD was associated with calpain-1 activation following T-type calcium channel opening, and resulted in the truncation of a regulatory subunit of PP2A, B56α. This signaling pathway was required for both the early and late phase of Arc translation during mGluR-LTD, through a mechanism involving mTOR and ribosomal protein S6 activation. In contrast, in hippocampal slices from calpain-1 knock-out (KO) mice, application of the mGluR agonist, DHPG, did not result in B56α truncation, increased Arc synthesis and reduced levels of membrane GluA1-containing AMPA receptors. Consistently, mGluR-LTD was impaired in calpain-1 KO mice, and the impairment could be rescued by phosphatase inhibitors, which also restored Arc translation in response to DHPG. Furthermore, calpain-1 KO mice exhibited impairment in fear memory extinction to tone presentation. These results indicate that calpain-1 plays a critical role in mGluR-LTD and is involved in many forms of synaptic plasticity and learning and memory.
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Affiliation(s)
- Guoqi Zhu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei 230038, China
| | - Victor Briz
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- VIB Center for the Biology of Disease, KU Leuven, 3000 Leuven, Belgium
| | - Jeff Seinfeld
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
| | - Yan Liu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
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27
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Klingebiel M, Dinekov M, Köhler C. Analysis of ribosomal protein S6 baseline phosphorylation and effect of tau pathology in the murine brain and human hippocampus. Brain Res 2017; 1659:121-135. [PMID: 28119058 DOI: 10.1016/j.brainres.2017.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 01/17/2023]
Abstract
We examined the distribution pattern of the phosphorylated 40S ribosomal subunit protein S6, a downstream target of the mTOR pathway, in the brains of 24-months-old human tau transgenic pR5 mice, non-transgenic littermates and in human hippocampi. We studied baseline levels of phosphorylated S6 and a possible effect of tau pathology. S6 phosphorylated at Ser235/236 (pS6Ser235/236) or Ser240/244 (pS6Ser240/244) has been used as a read-out of mTOR activity in several studies. The mTOR pathway regulates a wide variety of cellular functions including cell growth, ribosome biosynthesis, translational control and autophagy. Its dysregulation might underlie the neurodegenerative pathology of Alzheimer's disease and other tauopathies. pS6Ser235/236 and pS6Ser240/244 immunoreactivity in the mouse brain were widespread and similar distributed, but intensive pS6Ser235/236 immunoreactivity was more selective, especially highlighting certain brainstem regions. In the human hippocampus mainly granulovacuolar inclusions in neurons displayed pS6Ser235/236 immunoreactivity. In contrast, a considerable number of neurons displayed pS6Ser240/244 immunoreactivity in the cytoplasm without labeling of granulovacuolar inclusions. Except for a tendency of lower numbers of intensely phosphorylated S6-positive neurons in pR5 mice, the pattern of distribution of pS6Ser235/236 and pS6Ser240/244 immunoreactivity was largely unchanged when compared with non-transgenic mice and also when human hippocampi from AD cases and controls were compared. Similar to pR5 mice most neurons with hyper-phosphorylated tau in human hippocampi displayed no or only weak labeling for phosphorylated S6, suggesting that phosphorylated S6 is not especially associated with pathological tau, but is rather a feature of unaffected neurons.
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Affiliation(s)
- Maria Klingebiel
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany
| | - Maja Dinekov
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany
| | - Christoph Köhler
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany.
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28
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Palleria C, Leo A, Andreozzi F, Citraro R, Iannone M, Spiga R, Sesti G, Constanti A, De Sarro G, Arturi F, Russo E. Liraglutide prevents cognitive decline in a rat model of streptozotocin-induced diabetes independently from its peripheral metabolic effects. Behav Brain Res 2017; 321:157-169. [PMID: 28062257 DOI: 10.1016/j.bbr.2017.01.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/23/2016] [Accepted: 01/01/2017] [Indexed: 12/13/2022]
Abstract
Diabetes has been identified as a risk factor for cognitive dysfunctions. Glucagone like peptide 1 (GLP-1) receptor agonists have neuroprotective effects in preclinical animal models. We evaluated the effects of GLP-1 receptor agonist, liraglutide (LIR), on cognitive decline associated with diabetes. Furthermore, we studied LIR effects against hippocampal neurodegeneration induced by streptozotocin (STZ), a well-validated animal model of diabetes and neurodegeneration associated with cognitive decline. Diabetes and/or cognitive decline were induced in Wistar rats by intraperitoneal or intracerebroventricular injection of STZ and then rats were treated with LIR (300μg/kg daily subcutaneously) for 6 weeks. Rats underwent behavioral tests: Morris water maze, passive avoidance, forced swimming (FST), open field, elevated plus maze, rotarod tests. Furthermore, LIR effects on hippocampal neurodegeneration and mTOR pathway (AKT, AMPK, ERK and p70S6K) were assessed. LIR improved learning and memory only in STZ-treated animals. Anxiolytic effects were observed in all LIR-treated groups but pro-depressant effects in CTRL rats were observed. At a cellular/molecular level, intracerebroventricular STZ induced hippocampal neurodegeneration accompanied by decreased phosphorylation of AMPK, AKT, ERK and p70S6K. LIR reduced hippocampal neuronal death and prevented the decreased phosphorylation of AKT and p70S6K; AMPK was hyper-phosphorylated in comparison to CTRL group, while LIR had no effects on ERK. LIR reduced animal endurance in the rotarod test and this effect might be also linked to a reduction in locomotor activity during only the last two minutes of the FST. LIR had protective effects on cognitive functions in addition to its effects on blood glucose levels. LIR effects in the brain also comprised anxiolytic and pro-depressant actions (although influenced by reduced endurance). Finally, LIR protected from diabetes-dependent hippocampal neurodegeneration likely through an effect on mTOR pathway.
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Affiliation(s)
- Caterina Palleria
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Antonio Leo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Michelangelo Iannone
- CNR, Institute of Neurological Sciences, Pharmacology Section, Roccelletta di Borgia, Catanzaro, Italy
| | - Rosangela Spiga
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Giorgio Sesti
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Andrew Constanti
- Department of Pharmacology, UCL School of Pharmacy, 29/39 Brunswick Square, London, UK
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Franco Arturi
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, 88100, Viale Europa, Catanzaro, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy.
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Sun Y, Lipton JO, Boyle LM, Madsen JR, Goldenberg MC, Pascual-Leone A, Sahin M, Rotenberg A. Direct current stimulation induces mGluR5-dependent neocortical plasticity. Ann Neurol 2016; 80:233-46. [PMID: 27315032 DOI: 10.1002/ana.24708] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/07/2023]
Abstract
OBJECTIVE To obtain insights into mechanisms mediating changes in cortical excitability induced by cathodal transcranial direct current stimulation (tDCS). METHODS Neocortical slices were exposed to direct current stimulation (DCS) delivered through Ag/AgCl electrodes over a range of current orientations, magnitudes, and durations. DCS-induced cortical plasticity and its receptor dependency were measured as the change in layer II/III field excitatory postsynaptic potentials by a multielectrode array, both with and without neurotransmitter receptor blockers or allosteric modulators. In vivo, tDCS was delivered to intact mice scalp via surface electrodes. Molecular consequences of DCS in vitro or tDCS in vivo were tested by immunoblot of protein extracted from stimulated slices or the neocortex harvested from stimulated intact mice. RESULTS Cathodal DCS in vitro induces a long-term depression (DCS-LTD) of excitatory synaptic strength in both human and mouse neocortical slices. DCS-LTD is abolished with an mGluR5 negative allosteric modulator, mechanistic target of rapamycin (mTOR) inhibitor, and inhibitor of protein synthesis. However, DCS-LTD persists despite either γ-aminobutyric acid type A receptor or N-methyl-D-aspartate receptor inhibition. An mGluR5-positive allosteric modulator, in contrast, transformed transient synaptic depression resultant from brief DCS application into durable DCS-LTD. INTERPRETATION We identify a novel molecular pathway by which tDCS modulates cortical excitability, and indicate a capacity for synergistic interaction between tDCS and pharmacologic mGluR5 facilitation. The findings support exploration of cathodal tDCS as a treatment of neurologic conditions characterized by aberrant regional cortical excitability referable to mGluR5-mTOR signaling. Ann Neurol 2016;80:233-246.
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Affiliation(s)
- Yan Sun
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA.,Neuromodulation Program, Boston Children's Hospital, Boston, MA.,Program in Neuroscience, Harvard Medical School, Boston, MA
| | - Jonathan O Lipton
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Lara M Boyle
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
| | - Joseph R Madsen
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA
| | - Marti C Goldenberg
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Mustafa Sahin
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
| | - Alexander Rotenberg
- Department of Neurology and F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA.,Neuromodulation Program, Boston Children's Hospital, Boston, MA.,Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
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30
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Pirbhoy PS, Farris S, Steward O. Synaptic activation of ribosomal protein S6 phosphorylation occurs locally in activated dendritic domains. ACTA ACUST UNITED AC 2016; 23:255-69. [PMID: 27194793 PMCID: PMC4880148 DOI: 10.1101/lm.041947.116] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/07/2016] [Indexed: 01/08/2023]
Abstract
Previous studies have shown that induction of long-term potentiation (LTP) induces phosphorylation of ribosomal protein S6 (rpS6) in postsynaptic neurons, but the functional significance of rpS6 phosphorylation is poorly understood. Here, we show that synaptic stimulation that induces perforant path LTP triggers phosphorylation of rpS6 (p-rpS6) locally near active synapses. Using antibodies specific for phosphorylation at different sites (ser235/236 versus ser240/244), we show that strong synaptic activation led to dramatic increases in immunostaining throughout postsynaptic neurons with selectively higher staining for p-ser235/236 in the activated dendritic lamina. Following LTP induction, phosphorylation at ser235/236 was detectable by 5 min, peaked at 30 min, and was maintained for hours. Phosphorylation at both sites was completely blocked by local infusion of the NMDA receptor antagonist, APV. Despite robust induction of p-rpS6 following high frequency stimulation, assessment of protein synthesis by autoradiography revealed no detectable increases. Exploration of a novel environment led to increases in the number of p-rpS6-positive neurons throughout the forebrain in a pattern reminiscent of immediate early gene induction and many individual neurons that were p-rpS6-positive coexpressed Arc protein. Our results constrain hypotheses about the possible role of rpS6 phosphorylation in regulating postsynaptic protein synthesis during induction of synaptic plasticity.
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Affiliation(s)
- Patricia Salgado Pirbhoy
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory
| | - Shannon Farris
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA
| | - Oswald Steward
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA Department of Neurosurgery, University of California, Irvine, California 92697, USA
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31
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Hullinger R, Puglielli L. Molecular and cellular aspects of age-related cognitive decline and Alzheimer's disease. Behav Brain Res 2016; 322:191-205. [PMID: 27163751 DOI: 10.1016/j.bbr.2016.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 01/14/2023]
Abstract
As the population of people aged 60 or older continues to rise, it has become increasingly important to understand the molecular basis underlying age-related cognitive decline. In fact, a better understanding of aging biology will help us identify ways to maintain high levels of cognitive functioning throughout the aging process. Many cellular and molecular aspects of brain aging are shared with other organ systems; however, certain age-related changes are unique to the nervous system due to its structural, cellular and molecular complexity. Importantly, the brain appears to show differential changes throughout the aging process, with certain regions (e.g. frontal and temporal regions) being more vulnerable than others (e.g. brain stem). Within the medial temporal lobe, the hippocampus is especially susceptible to age-related changes. The important role of the hippocampus in age-related cognitive decline and in vulnerability to disease processes such as Alzheimer's disease has prompted this review, which will focus on the complexity of changes that characterize aging, and on the molecular connections that exist between normal aging and Alzheimer's disease. Finally, it will discuss behavioral interventions and emerging insights for promoting healthy cognitive aging.
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Affiliation(s)
- Rikki Hullinger
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Geriatric Research Education Clinical Center, VA Medical Center, Madison, WI 53705, USA.
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32
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Call CL, Hyson RL. Activity-dependent regulation of calcium and ribosomes in the chick cochlear nucleus. Neuroscience 2016; 316:201-8. [PMID: 26739326 DOI: 10.1016/j.neuroscience.2015.12.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 01/25/2023]
Abstract
Cochlea removal results in the death of 20-30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM). Two potentially cytotoxic events, a dramatic rise in intracellular calcium concentration ([Ca(2+)]i) and a decline in the integrity of ribosomes are observed within 1h of deafferentation. Glutamatergic input from the auditory nerve has been shown to preserve NM neuron health by activating metabotropic glutamate receptors (mGluRs), maintaining both normal [Ca(2+)]i and ribosomal integrity. One interpretation of these results is that a common mGluR-activated signaling cascade is required for the maintenance of both [Ca(2+)]i and ribosomal integrity. This could happen if both responses are influenced directly by a common messenger, or if the loss of mGluR activation causes changes in one component that secondarily causes changes in the other. The present studies tested this common-mediator hypothesis in slice preparations by examining activity-dependent regulation of [Ca(2+)]i and ribosomes in the same tissue after selectively blocking group I mGluRs (1-Aminoindan-1,5-dicarboxylic acid (AIDA)) or group II mGluRs (LY 341495) during unilateral auditory nerve stimulation. Changes in [Ca(2+)]i of NM neurons were measured using fura-2 ratiometric calcium imaging and the tissue was subsequently processed for Y10B immunoreactivity (Y10B-ir), an antibody that recognizes a ribosomal epitope. The group I mGluR antagonist blocked the activity-dependent regulation of both [Ca(2+)]i and Y10B-ir, but the group II antagonist blocked only the activity-dependent regulation of Y10B-ir. That is, even when group II receptors were blocked, stimulation continued to maintain low [Ca(2+)]i, but it did not maintain Y10B-ir. These results suggest a dissociation in how calcium and ribosomes are regulated in NM neurons and that ribosomes can be regulated through a mechanism that is independent of calcium regulation.
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Affiliation(s)
- C L Call
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - R L Hyson
- Department of Psychology, Florida State University, Tallahassee, FL, USA.
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33
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Sethna F, Zhang M, Kaphzan H, Klann E, Autio D, Cox CL, Wang H. Calmodulin activity regulates group I metabotropic glutamate receptor-mediated signal transduction and synaptic depression. J Neurosci Res 2016; 94:401-8. [PMID: 26864654 DOI: 10.1002/jnr.23719] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/22/2016] [Accepted: 01/26/2016] [Indexed: 01/06/2023]
Abstract
Group I metabotropic glutamate receptors (mGluR), including mGluR1 and mGluR 5 (mGluR1/5), are coupled to Gq and modulate activity-dependent synaptic plasticity. Direct activation of mGluR1/5 causes protein translation-dependent long-term depression (LTD). Although it has been established that intracellular Ca(2+) and the Gq-regulated signaling molecules are required for mGluR1/5 LTD, whether and how Ca(2+) regulates Gq signaling and upregulation of protein expression remain unknown. Through pharmacological inhibition, we tested the function of the Ca(2+) sensor calmodulin (CaM) in intracellular signaling triggered by the activation of mGluR1/5. CaM inhibitor N-[4-aminobutyl]-5-chloro-2-naphthalenesulfonamide hydrochloride (W13) suppressed the mGluR1/5-stimulated activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p70-S6 kinase 1 (S6K1) in hippocampal neurons. W13 also blocked the mGluR1/5 agonist-induced synaptic depression in hippocampal slices and in anesthetized mice. Consistent with the function of CaM, inhibiting the downstream targets Ca(2+) /CaM-dependent protein kinases (CaMK) blocked ERK1/2 and S6K1 activation. Furthermore, disruption of the CaM-CaMK-ERK1/2 signaling cascade suppressed the mGluR1/5-stimulated upregulation of Arc expression. Altogether, our data suggest CaM as a new Gq signaling component for coupling Ca(2+) and protein upregulation and regulating mGluR1/5-mediated synaptic modification.
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Affiliation(s)
- Ferzin Sethna
- Genetics Program, Michigan State University, East Lansing, Michigan
| | - Ming Zhang
- Department of Physiology, Michigan State University, East Lansing, Michigan.,Neuroscience Program, Michigan State University, East Lansing, Michigan.,Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, China
| | - Hanoch Kaphzan
- Center for Neural Science, New York University, New York, New York.,Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York
| | - Dawn Autio
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Charles L Cox
- Department of Physiology, Michigan State University, East Lansing, Michigan.,Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Hongbing Wang
- Department of Physiology, Michigan State University, East Lansing, Michigan.,Neuroscience Program, Michigan State University, East Lansing, Michigan
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34
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Biever A, Valjent E, Puighermanal E. Ribosomal Protein S6 Phosphorylation in the Nervous System: From Regulation to Function. Front Mol Neurosci 2015; 8:75. [PMID: 26733799 PMCID: PMC4679984 DOI: 10.3389/fnmol.2015.00075] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/23/2015] [Indexed: 01/31/2023] Open
Abstract
Since the discovery of the phosphorylation of the 40S ribosomal protein S6 (rpS6) about four decades ago, much effort has been made to uncover the molecular mechanisms underlying the regulation of this post-translational modification. In the field of neuroscience, rpS6 phosphorylation is commonly used as a readout of the mammalian target of rapamycin complex 1 signaling activation or as a marker for neuronal activity. Nevertheless, its biological role in neurons still remains puzzling. Here we review the pharmacological and physiological stimuli regulating this modification in the nervous system as well as the pathways that transduce these signals into rpS6 phosphorylation. Altered rpS6 phosphorylation observed in various genetic and pathophysiological mouse models is also discussed. Finally, we examine the current state of knowledge on the physiological role of this post-translational modification and highlight the questions that remain to be addressed.
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Affiliation(s)
- Anne Biever
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emmanuel Valjent
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emma Puighermanal
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
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35
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Inhibition of Group I Metabotropic Glutamate Receptors Reverses Autistic-Like Phenotypes Caused by Deficiency of the Translation Repressor eIF4E Binding Protein 2. J Neurosci 2015; 35:11125-32. [PMID: 26245973 DOI: 10.1523/jneurosci.4615-14.2015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Exacerbated mRNA translation during brain development has been linked to autism spectrum disorders (ASDs). Deletion of the eukaryotic initiation factor 4E (eIF4E)-binding protein 2 gene (Eif4ebp2), encoding the suppressor of mRNA translation initiation 4E-BP2, leads to an imbalance in excitatory-to-inhibitory neurotransmission and ASD-like behaviors. Inhibition of group I metabotropic glutamate receptors (mGluRs) mGluR1 and mGluR5 reverses the autistic phenotypes in several ASD mouse models. Importantly, these receptors control synaptic physiology via activation of mRNA translation. We investigated the potential reversal of autistic-like phenotypes in Eif4ebp2(-/-) mice by using antagonists of mGluR1 (JNJ16259685) or mGluR5 (fenobam). Augmented hippocampal mGluR-induced long-term depression (LTD; or chemically induced mGluR-LTD) in Eif4ebp2(-/-) mice was rescued by mGluR1 or mGluR5 antagonists. While rescue by mGluR5 inhibition occurs through the blockade of a protein synthesis-dependent component of LTD, normalization by mGluR1 antagonists requires the activation of protein synthesis. Synaptically induced LTD was deficient in Eif4ebp2(-/-) mice, and this deficit was not rescued by group I mGluR antagonists. Furthermore, a single dose of mGluR1 (0.3 mg/kg) or mGluR5 (3 mg/kg) antagonists in vivo reversed the deficits in social interaction and repetitive behaviors (marble burying) in Eif4ebp2(-/-) mice. Our results demonstrate that Eif4ebp2(-/-) mice serve as a relevant model to test potential therapies for ASD symptoms. In addition, we provide substantive evidence that the inhibition of mGluR1/mGluR5 is an effective treatment for physiological and behavioral alterations caused by exacerbated mRNA translation initiation. SIGNIFICANCE STATEMENT Exacerbated mRNA translation during brain development is associated with several autism spectrum disorders (ASDs). We recently demonstrated that the deletion of a negative regulator of mRNA translation initiation, the eukaryotic initiation factor 4E-binding protein 2, leads to ASD-like behaviors and increased excitatory synaptic activity. Here we demonstrated that autistic behavioral and electrophysiological phenotypes can be treated in adult mice with antagonists of group I metabotropic glutamate receptors (mGluRs), which have been previously used in other ASD models (i.e., fragile X syndrome). These findings support the use of group I mGluR antagonists as a potential therapy that extends to autism models involving exacerbated mRNA translation initiation.
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36
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Niere F, Namjoshi S, Song E, Dilly GA, Schoenhard G, Zemelman BV, Mechref Y, Raab-Graham KF. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC). Mol Cell Proteomics 2015; 15:426-44. [PMID: 26419955 DOI: 10.1074/mcp.m115.055079] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 01/05/2023] Open
Abstract
Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder-neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states.
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Affiliation(s)
- Farr Niere
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas; ‖Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas
| | - Sanjeev Namjoshi
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas
| | - Ehwang Song
- **Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Geoffrey A Dilly
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas
| | - Grant Schoenhard
- ‡‡Pain Therapeutics, Inc., 7801 N Capital of Texas Hwy, #260, Austin, Texas 78731
| | - Boris V Zemelman
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas
| | - Yehia Mechref
- **Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Kimberly F Raab-Graham
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas; ‖Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas; ‡‡Pain Therapeutics, Inc., 7801 N Capital of Texas Hwy, #260, Austin, Texas 78731
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Subramanian M, Timmerman CK, Schwartz JL, Pham DL, Meffert MK. Characterizing autism spectrum disorders by key biochemical pathways. Front Neurosci 2015; 9:313. [PMID: 26483618 PMCID: PMC4586332 DOI: 10.3389/fnins.2015.00313] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/20/2015] [Indexed: 12/29/2022] Open
Abstract
The genetic and phenotypic heterogeneity of autism spectrum disorders (ASD) presents a substantial challenge for diagnosis, classification, research, and treatment. Investigations into the underlying molecular etiology of ASD have often yielded mixed and at times opposing findings. Defining the molecular and biochemical underpinnings of heterogeneity in ASD is crucial to our understanding of the pathophysiological development of the disorder, and has the potential to assist in diagnosis and the rational design of clinical trials. In this review, we propose that genetically diverse forms of ASD may be usefully parsed into entities resulting from converse patterns of growth regulation at the molecular level, which lead to the correlates of general synaptic and neural overgrowth or undergrowth. Abnormal brain growth during development is a characteristic feature that has been observed both in children with autism and in mouse models of autism. We review evidence from syndromic and non-syndromic ASD to suggest that entities currently classified as autism may fundamentally differ by underlying pro- or anti-growth abnormalities in key biochemical pathways, giving rise to either excessive or reduced synaptic connectivity in affected brain regions. We posit that this classification strategy has the potential not only to aid research efforts, but also to ultimately facilitate early diagnosis and direct appropriate therapeutic interventions.
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Affiliation(s)
- Megha Subramanian
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Christina K Timmerman
- Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Joshua L Schwartz
- Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Daniel L Pham
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Mollie K Meffert
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
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38
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Shehata M, Inokuchi K. Does autophagy work in synaptic plasticity and memory? Rev Neurosci 2015; 25:543-57. [PMID: 24651020 DOI: 10.1515/revneuro-2014-0002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/17/2014] [Indexed: 12/12/2022]
Abstract
Many studies have reported the roles played by regulated proteolysis in neural plasticity and memory. Within this context, most of the research focused on the ubiquitin-proteasome system and the endosome-lysosome system while giving lesser consideration to another major protein degradation system, namely, autophagy. Although autophagy intersects with many of the pathways known to underlie synaptic plasticity and memory, only few reports related autophagy to synaptic remodeling. These pathways include PI3K-mTOR pathway and endosome-dependent proteolysis. In this review, we will discuss several lines of evidence supporting a physiological role of autophagy in memory processes, and the possible mechanistic scenarios for how autophagy could fulfill this function.
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39
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PKA-dependent phosphorylation of ribosomal protein S6 does not correlate with translation efficiency in striatonigral and striatopallidal medium-sized spiny neurons. J Neurosci 2015; 35:4113-30. [PMID: 25762659 DOI: 10.1523/jneurosci.3288-14.2015] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ribosomal protein S6 (rpS6), a component of the 40S ribosomal subunit, is phosphorylated on several residues in response to numerous stimuli. Although commonly used as a marker for neuronal activity, its upstream mechanisms of regulation are poorly studied and its role in protein synthesis remains largely debated. Here, we demonstrate that the psychostimulant d-amphetamine (d-amph) markedly increases rpS6 phosphorylation at Ser235/236 sites in both crude and synaptoneurosomal preparations of the mouse striatum. This effect occurs selectively in D1R-expressing medium-sized spiny neurons (MSNs) and requires the cAMP/PKA/DARPP-32/PP-1 cascade, whereas it is independent of mTORC1/p70S6K, PKC, and ERK signaling. By developing a novel assay to label nascent peptidic chains, we show that the rpS6 phosphorylation induced in striatonigral MSNs by d-amph, as well as in striatopallidal MSNs by the antipsychotic haloperidol or in both subtypes by papaverine, is not correlated with the translation of global or 5' terminal oligopyrimidine tract mRNAs. Together, these results provide novel mechanistic insights into the in vivo regulation of the post-translational modification of rpS6 in the striatum and point out the lack of a relationship between PKA-dependent rpS6 phosphorylation and translation efficiency.
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40
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Lai KO, Liang Z, Fei E, Huang H, Ip NY. Cyclin-dependent Kinase 5 (Cdk5)-dependent Phosphorylation of p70 Ribosomal S6 Kinase 1 (S6K) Is Required for Dendritic Spine Morphogenesis. J Biol Chem 2015; 290:14637-46. [PMID: 25903132 DOI: 10.1074/jbc.m114.627117] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Indexed: 11/06/2022] Open
Abstract
The maturation and maintenance of dendritic spines depends on neuronal activity and protein synthesis. One potential mechanism involves mammalian target of rapamycin, which promotes protein synthesis through phosphorylation of eIF4E-binding protein and p70 ribosomal S6 kinase 1 (S6K). Upon extracellular stimulation, mammalian target of rapamycin phosphorylates S6K at Thr-389. S6K also undergoes phosphorylation at other sites, including four serine residues in the autoinhibitory domain. Despite extensive biochemical studies, the importance of phosphorylation in the autoinhibitory domain in S6K function remains unresolved, and its role has not been explored in the cellular context. Here we demonstrated that S6K in neuron was phosphorylated at Ser-411 within the autoinhibitory domain by cyclin-dependent kinase 5. Ser-411 phosphorylation was regulated by neuronal activity and brain-derived neurotrophic factor (BDNF). Knockdown of S6K in hippocampal neurons by RNAi led to loss of dendritic spines, an effect that mimics neuronal activity blockade by tetrodotoxin. Notably, coexpression of wild type S6K, but not the phospho-deficient S411A mutant, could rescue the spine defects. These findings reveal the importance of cyclin-dependent kinase 5-mediated phosphorylation of S6K at Ser-411 in spine morphogenesis driven by BDNF and neuronal activity.
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Affiliation(s)
- Kwok-On Lai
- From the Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhuoyi Liang
- From the Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Erkang Fei
- From the Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Huiqian Huang
- From the Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Nancy Y Ip
- From the Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
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Buffington SA, Huang W, Costa-Mattioli M. Translational control in synaptic plasticity and cognitive dysfunction. Annu Rev Neurosci 2015; 37:17-38. [PMID: 25032491 DOI: 10.1146/annurev-neuro-071013-014100] [Citation(s) in RCA: 251] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Activity-dependent changes in the strength of synaptic connections are fundamental to the formation and maintenance of memory. The mechanisms underlying persistent changes in synaptic strength in the hippocampus, specifically long-term potentiation and depression, depend on new protein synthesis. Such changes are thought to be orchestrated by engaging the signaling pathways that regulate mRNA translation in neurons. In this review, we discuss the key regulatory pathways that govern translational control in response to synaptic activity and the mRNA populations that are specifically targeted by these pathways. The critical contribution of regulatory control over new protein synthesis to proper cognitive function is underscored by human disorders associated with either silencing or mutation of genes encoding proteins that directly regulate translation. In light of these clinical implications, we also consider the therapeutic potential of targeting dysregulated translational control to treat cognitive disorders of synaptic dysfunction.
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Affiliation(s)
- Shelly A Buffington
- Department of Neuroscience, Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas 77030; , ,
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42
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Su ZW, Liao JY, Zhang H, Zhang T, Wu F, Tian XH, Zhang FT, Sun WW, Cui QL. Postnatal high-protein diet improves learning and memory in premature rats via activation of mTOR signaling. Brain Res 2015; 1611:1-7. [PMID: 25796434 DOI: 10.1016/j.brainres.2015.01.052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/19/2015] [Accepted: 01/23/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE The present study investigated whether a high-protein diet affects spatial learning and memory in premature rats via modulation of mammalian target of rapamycin (mTOR) signaling. METHODS Pre- and full-term Sprague-Dawley pups were fed a normal (18% protein) or high-protein (30% protein) diet (HPD) for 6 or 8 weeks after weaning. Spatial learning and memory were tested in the Morris water maze at week 6 and 8. The activation of mTOR signaling pathway components was evaluated by western blotting. RESULTS Spatial memory performance of premature rats consuming a normal and HPD was lower than that of full-term rats on the same diet at 6 weeks, and was associated with lower levels of ribosomal protein S6 kinase p70 subtype (p70S6K) and initiation factor 4E-binding protein 1 (4EBP1) phosphorylation in the hippocampus. Spatial memory was improved in 8-week-old premature rats on an HPD as compared to those on a normal diet. Premature rats on an HPD had p70S6K and 4EBP1 phosphorylation levels in the hippocampus that were comparable to those of full-term rats on an HPD. CONCLUSION Long-term consumption of a protein-rich diet can restore the impairment in learning and memory in pre-term rats via upregulation of mTOR/p70S6K signaling.
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Affiliation(s)
- Zhi-Wen Su
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China
| | - Jia-Yi Liao
- Jinan University, Guangzhong, China; Guangzhou Yuexiu District Children׳s Hospital, Guangzhong, China
| | - Hui Zhang
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China
| | - Tao Zhang
- Guangzhou Yuexiu District Children׳s Hospital, Guangzhong, China
| | - Fan Wu
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China
| | - Xiao-Hua Tian
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China
| | - Fei-Tong Zhang
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China
| | - Wei-Wen Sun
- Institute of Neuroscience Guangzhou Medical University, Guangzhong, China
| | - Qi-Liang Cui
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhong, China.
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Extinction, applied after retrieval of auditory fear memory, selectively increases zinc-finger protein 268 and phosphorylated ribosomal protein S6 expression in prefrontal cortex and lateral amygdala. Neurobiol Learn Mem 2014; 115:78-85. [DOI: 10.1016/j.nlm.2014.08.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/13/2014] [Accepted: 08/29/2014] [Indexed: 11/19/2022]
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Abelaira HM, Réus GZ, Neotti MV, Quevedo J. The role of mTOR in depression and antidepressant responses. Life Sci 2014; 101:10-4. [PMID: 24582593 DOI: 10.1016/j.lfs.2014.02.014] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/21/2014] [Accepted: 02/14/2014] [Indexed: 01/01/2023]
Abstract
The aim of this study was to characterize the mTOR signaling cascade in depression and the actions that antidepressant drugs have on this pathway. Herein, a literature review was performed by verification and comparison of textbooks and journal articles that describe the characterization of the mTOR signaling cascade and its relationship to depression and antidepressant drugs, especially ketamine. Postmortem studies have shown robust deficits in the mammalian target of rapamycin (mTOR) signaling in the prefrontal cortex of subjects diagnosed with major depressive disorder. However, besides the mTOR signaling pathway having an antidepressant response to various drugs, this seems to be more associated with antidepressant N-methyl-d-aspartate (NMDA) receptor antagonists, such as ketamine. The characterization of the mTOR signaling pathway in depression and its action in response to antidepressants show great potential for the identification of new therapeutic targets for the development of antidepressant drugs.
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Affiliation(s)
- Helena M Abelaira
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
| | - Gislaine Z Réus
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil; Center for Experimental Models in Psychiatry, Department of Psychiatry and Behavioral Sciences, The University of Texas Medical School at Houston, Houston, TX, USA.
| | - Morgana V Neotti
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
| | - João Quevedo
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil; Center for Experimental Models in Psychiatry, Department of Psychiatry and Behavioral Sciences, The University of Texas Medical School at Houston, Houston, TX, USA
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45
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Roh SE, Hong YH, Jang DC, Kim J, Kim SJ. Lipid rafts serve as signaling platforms for mGlu1 receptor-mediated calcium signaling in association with caveolin. Mol Brain 2014; 7:9. [PMID: 24512690 PMCID: PMC3937055 DOI: 10.1186/1756-6606-7-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/30/2014] [Indexed: 11/24/2022] Open
Abstract
Background Group I metabotropic glutamate receptors (mGlu1/5 receptors) have important roles in synaptic activity in the central nervous system. They modulate neuronal excitability by mobilizing intracellular Ca2+ following receptor activation. Also, accumulating evidence has indicated the association of Ca2+ signaling with lipid rafts. Caveolin, an adaptor protein found in a specialized subset of lipid rafts, has been reported to promote the localization of membrane proteins to lipid rafts. Results In the present study, we investigated the role of lipid rafts on the mGlu1α receptor-mediated Ca2+ signaling in association with caveolin in hippocampal primary neurons and HEK293 cells. We show that the disruption of lipid rafts using methyl-β-cyclodextrin markedly decreased mGlu1α receptor-mediated Ca2+ transients and lipid rafts localization of the receptor. Furthermore, transfection of mGlu1α receptor with mutated caveolin-binding domain reduced localization of the receptor to lipid rafts. Also, application of a peptide blocker of mGlu1α receptor and caveolin binding reduced the Ca2+ signaling and the lipid rafts localization. Conclusions Taken together, these results suggest that the binding of mGlu1α receptor to caveolin is crucial for its lipid rafts localization and mGlu1α receptor-mediated Ca2+ transients.
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Affiliation(s)
| | | | | | | | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, 28, Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea.
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46
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Gururajan A, van den Buuse M. Is the mTOR-signalling cascade disrupted in Schizophrenia? J Neurochem 2013; 129:377-87. [PMID: 24266366 DOI: 10.1111/jnc.12622] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/07/2013] [Accepted: 11/10/2013] [Indexed: 02/01/2023]
Abstract
The mammalian target of rapamycin (mTOR) signalling cascade is involved in the intracellular regulation of protein synthesis, specifically for proteins involved in controlling neuronal morphology and facilitating synaptic plasticity. Research has revealed that the activity of the mTOR cascade is influenced by several extracellular and environmental factors that have been implicated in schizophrenia. Therefore, there is reason to believe that one of the downstream consequences of dysfunction or hypofunction of these factors in schizophrenia is disrupted mTOR signalling and hence impaired protein synthesis. This results in abnormal neurodevelopment and deficient synaptic plasticity, outcomes which could underlie some of the positive, negative and cognitive symptoms of schizophrenia. This review will discuss the functional roles of the mTOR cascade and present evidence in support of a novel mTOR-based hypothesis of the neuropathology of schizophrenia. During neurodevelopment, genetic and epigenetic factors can disrupt mTOR signalling which affects synthesis of proteins essential for correct neuronal growth and network connectivity. This renders the CNS particularly vulnerable to the effects of secondary factors during adolescence which increases the risk of developing schizophrenia in adulthood. This review discusses the functional roles of the mTOR cascade and presents evidence in support of a novel mTOR-based hypothesis of the neuropathology of schizophrenia. Testing this hypothesis will advance our understanding of the aetiology of this illness and reveal novel therapeutic targets.
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Affiliation(s)
- Anand Gururajan
- Behavioural Neuroscience Laboratory, The Florey Institute of Neuroscience & Mental Health, Parkville, Vic., Australia
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47
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mTOR complexes in neurodevelopmental and neuropsychiatric disorders. Nat Neurosci 2013; 16:1537-43. [PMID: 24165680 DOI: 10.1038/nn.3546] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 09/11/2013] [Indexed: 02/07/2023]
Abstract
The mechanistic target of rapamycin (mTOR) acts as a highly conserved signaling "hub" that integrates neuronal activity and a variety of synaptic inputs. mTOR is found in two functionally distinct complexes, mTORC1 and mTORC2, that crucially control long-term synaptic efficacy and memory storage. Dysregulation of mTOR signaling is associated with neurodevelopmental and neuropsychiatric disorders. In this Review, we describe the most recent advances in studies of mTOR signaling in the brain and the possible mechanisms underlying the many different functions of the mTOR complexes in neurological diseases. In addition, we discuss the medical relevance of these findings.
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Bateup HS, Denefrio CL, Johnson CA, Saulnier JL, Sabatini BL. Temporal dynamics of a homeostatic pathway controlling neural network activity. Front Mol Neurosci 2013; 6:28. [PMID: 24065881 PMCID: PMC3776619 DOI: 10.3389/fnmol.2013.00028] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 08/24/2013] [Indexed: 11/13/2022] Open
Abstract
Neurons use a variety of mechanisms to homeostatically regulate neural network activity in order to maintain firing in a bounded range. One such process involves the bi-directional modulation of excitatory synaptic drive in response to chronic changes in network activity. Down-scaling of excitatory synapses in response to high activity requires Arc-dependent endocytosis of glutamate receptors. However, the temporal dynamics and signaling pathways regulating Arc during homeostatic plasticity are not well understood. Here we determine the relative contribution of transcriptional and translational control in the regulation of Arc, the signaling pathways responsible for the activity-dependent production of Arc, and the time course of these signaling events as they relate to the homeostatic adjustment of network activity in hippocampal neurons. We find that an ERK1/2-dependent transcriptional pathway active within 1-2 h of up-regulated network activity induces Arc leading to a restoration of network spiking rates within 12 h. Under basal and low activity conditions, specialized mechanisms are in place to rapidly degrade Arc mRNA and protein such that they have half-lives of less than 1 h. In addition, we find that while mTOR signaling is regulated by network activity on a similar time scale, mTOR-dependent translational control is not a major regulator of Arc production or degradation suggesting that the signaling pathways underlying homeostatic plasticity are distinct from those mediating synapse-specific forms of synaptic depression.
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Affiliation(s)
- Helen S Bateup
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School Boston, MA, USA
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Graber TE, McCamphill PK, Sossin WS. A recollection of mTOR signaling in learning and memory. Learn Mem 2013; 20:518-30. [PMID: 24042848 DOI: 10.1101/lm.027664.112] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and mTORC2) that have different substrate specificities, thus allowing for distinct functions at synapses. We will examine how learning activates the mTOR complexes, survey the critical effectors of this pathway in the context of synaptic plasticity, and assess whether mTOR plays an instructive or permissive role in generating molecular memory traces.
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Affiliation(s)
- Tyson E Graber
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A-2B4, Canada
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50
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McBride EG, Rubel EW, Wang Y. Afferent regulation of chicken auditory brainstem neurons: rapid changes in phosphorylation of elongation factor 2. J Comp Neurol 2013; 521:1165-83. [PMID: 22987813 DOI: 10.1002/cne.23227] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/27/2012] [Accepted: 09/07/2012] [Indexed: 12/21/2022]
Abstract
The relationships between protein synthesis and neuronal survival are poorly understood. In chicken nucleus magnocellularis (NM), significant alterations in overall protein synthesis precede neuronal death induced by deprivation of excitatory afferent activity. Previously we demonstrated an initial reduction in the overall rate of protein synthesis in all deprived NM neurons, followed by quick recovery (starting at 6 hours) in some, but not all, neurons. Neurons with recovered protein synthesis ultimately survive, whereas others become "ghost" cells (no detectable Nissl substance) at 12-24 hours and die within 48 hours. To explore the mechanisms underlying this differential influence of afferent input on protein synthesis and cell survival, the current study investigates the involvement of eukaryotic translation elongation factor 2 (eEF2), the phosphorylation of which reduces overall protein synthesis. Using immunocytochemistry for either total or phosphorylated eEF2 (p-eEF2), we found significant reductions in the level of phosphorylated, but not total, eEF2 in NM neurons as early as 0.5-1 hour following cochlea removal. Unexpectedly, neurons with low levels of p-eEF2 show reduced protein synthesis at 6 hours, indicated by a marker for active ribosomes. At 12 hours, all "ghost" cells exhibited little or no p-eEF2 staining, although not every neuron with a comparable low level of p-eEF2 was a "ghost" cell. These observations demonstrate that a reduced level of p-eEF2 is not responsible for immediate responses (including reduced overall protein synthesis) of a neuron to compromised afferent input but may impair the neuron's ability to initiate recovery signaling for survival and make the neuron more vulnerable to death.
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Affiliation(s)
- Ethan G McBride
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle, Washington 98195, USA
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