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Bonzanni M, Braga A, Saito T, Saido TC, Tesco G, Haydon PG. Adenosine deficiency facilitates CA1 synaptic hyperexcitability in the presymptomatic phase of a knock in mouse model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.24.590882. [PMID: 38712028 PMCID: PMC11071633 DOI: 10.1101/2024.04.24.590882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The disease's trajectory of Alzheimer's disease (AD) is associated with and worsened by hippocampal hyperexcitability. Here we show that during the asymptomatic stage in a knock in mouse model of Alzheimer's disease (APPNL-G-F/NL-G-F; APPKI), hippocampal hyperactivity occurs at the synaptic compartment, propagates to the soma and is manifesting at low frequencies of stimulation. We show that this aberrant excitability is associated with a deficient adenosine tone, an inhibitory neuromodulator, driven by reduced levels of CD39/73 enzymes, responsible for the extracellular ATP-to-adenosine conversion. Both pharmacologic (adenosine kinase inhibitor) and non-pharmacologic (ketogenic diet) restorations of the adenosine tone successfully normalize hippocampal neuronal activity. Our results demonstrated that neuronal hyperexcitability during the asymptomatic stage of a KI model of Alzheimer's disease originated at the synaptic compartment and is associated with adenosine deficient tone. These results extend our comprehension of the hippocampal vulnerability associated with the asymptomatic stage of Alzheimer's disease.
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Affiliation(s)
- Mattia Bonzanni
- Department of Neuroscience, Tufts University, Boston, MA, USA
| | - Alice Braga
- Department of Neuroscience, Tufts University, Boston, MA, USA
- Current address: Centre for Cardiovascular and 811 Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | - Philip G Haydon
- Department of Neuroscience, Tufts University, Boston, MA, USA
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2
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Majkutewicz I, Kurowska-Rucińska E, Ruciński J, Myślińska D, Grembecka B, Mantej J, Dzik KP. Diverse Efficacy of Dimethyl Fumarate in Alleviating the Late Streptozotocin-Induced Cognitive Impairment and Neuropathological Features in Rat. Mol Neurobiol 2024:10.1007/s12035-024-04024-8. [PMID: 38430351 DOI: 10.1007/s12035-024-04024-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Our previous study showed that dimethyl fumarate (DMF) treatment performed within three weeks after intracerebroventricular (ICV) injection of streptozotocin (STZ) attenuated spatial memory impairment, hippocampal neurodegeneration, and neuroinflammation in rats. The present study is aimed at verifying the hypothesis that DMF alleviates late effects of STZ (6 months after ICV injection) which reflects advanced stage of the Alzheimer's disease (AD) in human patients. Spatial memory was assessed with Morris water maze (MWM), general brain level of amyloid β (Aβ) and p-tau was measured by western blot, immunofluorescent labelling of active microglia (IBA1), Aβ and p-tau and histological assay of neurodegeneration (Fluoro-Jade C) were performed in hippocampus and cortex. Two-week oral therapy with DMF normalized spatial memory disrupted by STZ but had no influence on general brain level of Aβ and p-tau. However, immunofluorescence showed local reduction of Aβ aggregates number in parietal cortex and p-tau+ cells in CA2 hippocampal area. Microgliosis was alleviated by DMF in CA1 area and parietal cortex. DMF-treated STZ injected rats showed higher number of Aβ containing microglia than untreated group in CA2 and frontal cortex, which may be the result of increased phagocytic activity in these areas after DMF treatment. STZ-induced neurodegeneration was alleviated by DMF in dentate gyrus and frontal cortex. In conclusion DMF treatment exerts beneficial effect on spatial memory in the rat model of late stage of AD, but weakly influences neuropathological features, as only local reduction in number of Aβ aggregates, p-tau containing cells, neurodegeneration, and microgliosis was found.
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Affiliation(s)
- Irena Majkutewicz
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland.
| | | | - Jan Ruciński
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Dorota Myślińska
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Beata Grembecka
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Jagoda Mantej
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Katarzyna P Dzik
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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3
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Kawamura M, Sekino Y. Adenosine A 1 receptor antagonist-induced facilitation of postsynaptic AMPA currents in pyramidal neurons of the rat hippocampal CA2 area. Purinergic Signal 2023; 19:623-632. [PMID: 36074226 PMCID: PMC10754797 DOI: 10.1007/s11302-022-09897-9] [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: 05/06/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022] Open
Abstract
Adenosine A1 receptors (A1R) are widely expressed in hippocampal pyramidal neurons and their presynaptic terminals. It is well known that endogenous adenosine regulates hippocampal function through the activation of A1R in hippocampal pyramidal neurons and has been reported that blockade of A1R induces stronger potentiation of excitatory synaptic transmission in CA2 pyramidal neurons than in CA1 pyramidal neurons. This strong potentiation of CA2 neurons is thought to be caused by the specific modulation of excitatory synaptic transmission through postsynaptic A1R. However, the direct effects of A1R on postsynaptic AMPA channels remain unknown because of the technical difficulties of patch-clamp recording from mature hippocampal CA2 neurons. We recorded synaptic currents from pyramidal neurons in CA1 and CA2 and analyzed the effects of an A1R antagonist on stimulation-evoked synaptic transmission and local application-induced postsynaptic AMPA currents. The antagonist increased the amplitude of evoked synaptic transmission in neurons in both CA1 and CA2. This facilitation was larger in pyramidal neurons in CA2 than in CA1. The antagonist also increased postsynaptic AMPA currents in neurons in CA2 but not in CA1. This facilitation of CA2 AMPA currents was occluded by the intracellular application of a G-protein blocker. Even with the blockade of postsynaptic G-protein signaling, the A1R antagonist increased evoked synaptic transmission in neurons in CA2. These results suggest that synaptic transmission in pyramidal neurons in CA2 is regulated by both presynaptic and postsynaptic A1R. Moreover, A1R regulate excitatory synaptic transmission in pyramidal neurons in CA2 through the characteristic postsynaptic modulation of AMPA currents.
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Affiliation(s)
- Masahito Kawamura
- Department of Pharmacology, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo, 105-8461, Japan.
| | - Yuko Sekino
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
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4
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RGS14 Regulation of Post-Synaptic Signaling and Spine Plasticity in Brain. Int J Mol Sci 2021; 22:ijms22136823. [PMID: 34201943 PMCID: PMC8268017 DOI: 10.3390/ijms22136823] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
The regulator of G-protein signaling 14 (RGS14) is a multifunctional signaling protein that regulates post synaptic plasticity in neurons. RGS14 is expressed in the brain regions essential for learning, memory, emotion, and stimulus-induced behaviors, including the basal ganglia, limbic system, and cortex. Behaviorally, RGS14 regulates spatial and object memory, female-specific responses to cued fear conditioning, and environmental- and psychostimulant-induced locomotion. At the cellular level, RGS14 acts as a scaffolding protein that integrates G protein, Ras/ERK, and calcium/calmodulin signaling pathways essential for spine plasticity and cell signaling, allowing RGS14 to naturally suppress long-term potentiation (LTP) and structural plasticity in hippocampal area CA2 pyramidal cells. Recent proteomics findings indicate that RGS14 also engages the actomyosin system in the brain, perhaps to impact spine morphogenesis. Of note, RGS14 is also a nucleocytoplasmic shuttling protein, where its role in the nucleus remains uncertain. Balanced nuclear import/export and dendritic spine localization are likely essential for RGS14 neuronal functions as a regulator of synaptic plasticity. Supporting this idea, human genetic variants disrupting RGS14 localization also disrupt RGS14’s effects on plasticity. This review will focus on the known and unexplored roles of RGS14 in cell signaling, physiology, disease and behavior.
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Lehr AB, Kumar A, Tetzlaff C, Hafting T, Fyhn M, Stöber TM. CA2 beyond social memory: Evidence for a fundamental role in hippocampal information processing. Neurosci Biobehav Rev 2021; 126:398-412. [PMID: 33775693 DOI: 10.1016/j.neubiorev.2021.03.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 01/16/2023]
Abstract
Hippocampal region CA2 has received increased attention due to its importance in social recognition memory. While its specific function remains to be identified, there are indications that CA2 plays a major role in a variety of situations, widely extending beyond social memory. In this targeted review, we highlight lines of research which have begun to converge on a more fundamental role for CA2 in hippocampus-dependent memory processing. We discuss recent proposals that speak to the computations CA2 may perform within the hippocampal circuit.
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Affiliation(s)
- Andrew B Lehr
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany; Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway; Centre for Integrative Neuroplasticity, University of Oslo, Norway.
| | - Arvind Kumar
- Department of Computational Science and Technology, KTH Royal Institute of Technology, Sweden
| | - Christian Tetzlaff
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany
| | - Torkel Hafting
- Centre for Integrative Neuroplasticity, University of Oslo, Norway; Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Marianne Fyhn
- Centre for Integrative Neuroplasticity, University of Oslo, Norway; Department of Biosciences, University of Oslo, Norway
| | - Tristan M Stöber
- Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway; Centre for Integrative Neuroplasticity, University of Oslo, Norway; Department of Informatics, University of Oslo, Norway.
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Lehr AB, McDonald RJ, Thorpe CM, Tetzlaff C, Deibel SH. A local circadian clock for memory? Neurosci Biobehav Rev 2021; 127:946-957. [PMID: 33476672 DOI: 10.1016/j.neubiorev.2020.11.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/20/2022]
Abstract
The master clock, suprachiasmatic nucleus, is believed to control peripheral circadian oscillators throughout the brain and body. However, recent data suggest there is a circadian clock involved in learning and memory, potentially housed in the hippocampus, which is capable of acting independently of the master clock. Curiously, the hippocampal clock appears to be influenced by the master clock and by hippocampal dependent learning, while under certain conditions it may also revert to its endogenous circadian rhythm. Here we propose a mechanism by which the hippocampal clock could locally determine the nature of its entrainment. We introduce a novel theoretical framework, inspired by but extending beyond the hippocampal memory clock, which provides a new perspective on how circadian clocks throughout the brain coordinate their rhythms. Importantly, a local clock for memory would suggest that hippocampal-dependent learning at the same time every day should improve memory, opening up a range of possibilities for non-invasive therapies to alleviate the detrimental effects of circadian rhythm disruption on human health.
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Affiliation(s)
- Andrew B Lehr
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany
| | | | | | - Christian Tetzlaff
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany
| | - Scott H Deibel
- Department of Psychology, Memorial University of Newfoundland, Canada.
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Therapeutic potential of targeting G protein-gated inwardly rectifying potassium (GIRK) channels in the central nervous system. Pharmacol Ther 2021; 223:107808. [PMID: 33476640 DOI: 10.1016/j.pharmthera.2021.107808] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
G protein-gated inwardly rectifying potassium channels (Kir3/GirK) are important for maintaining resting membrane potential, cell excitability and inhibitory neurotransmission. Coupled to numerous G protein-coupled receptors (GPCRs), they mediate the effects of many neurotransmitters, neuromodulators and hormones contributing to the general homeostasis and particular synaptic plasticity processes, learning, memory and pain signaling. A growing number of behavioral and genetic studies suggest a critical role for the appropriate functioning of the central nervous system, as well as their involvement in many neurologic and psychiatric conditions, such as neurodegenerative diseases, mood disorders, attention deficit hyperactivity disorder, schizophrenia, epilepsy, alcoholism and drug addiction. Hence, GirK channels emerge as a very promising tool to be targeted in the current scenario where these conditions already are or will become a global public health problem. This review examines recent findings on the physiology, function, dysfunction, and pharmacology of GirK channels in the central nervous system and highlights the relevance of GirK channels as a worthful potential target to improve therapies for related diseases.
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Caruana DA, Dudek SM. Adenosine A 1 Receptor-Mediated Synaptic Depression in the Developing Hippocampal Area CA2. Front Synaptic Neurosci 2020; 12:21. [PMID: 32612520 PMCID: PMC7307308 DOI: 10.3389/fnsyn.2020.00021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022] Open
Abstract
Immunolabeling for adenosine A1 receptors (A1Rs) is high in hippocampal area CA2 in adult rats, and the potentiating effects of caffeine or other A1R-selective antagonists on synaptic responses are particularly robust at Schaffer collateral synapses in CA2. Interestingly, the pronounced staining for A1Rs in CA2 is not apparent until rats are 4 weeks old, suggesting that developmental changes other than receptor distribution underlie the sensitivity of CA2 synapses to A1R antagonists in young animals. To evaluate the role of A1R-mediated postsynaptic signals at these synapses, we tested whether A1R agonists regulate synaptic transmission at Schaffer collateral inputs to CA2 and CA1. We found that the selective A1R agonist CCPA caused a lasting depression of synaptic responses in both CA2 and CA1 neurons in slices obtained from juvenile rats (P14), but that the effect was observed only in CA2 in slices prepared from adult animals (~P70). Interestingly, blocking phosphodiesterase activity with rolipram inhibited the CCPA-induced depression in CA1, but not in CA2, indicative of robust phosphodiesterase activity in CA1 neurons. Likewise, synaptic responses in CA2 and CA1 differed in their sensitivity to the adenylyl cyclase activator, forskolin, in that it increased synaptic transmission in CA2, but had little effect in CA1. These findings suggest that the A1R-mediated synaptic depression tracks the postnatal development of immunolabeling for A1Rs and that the enhanced sensitivity to antagonists in CA2 at young ages is likely due to robust adenylyl cyclase activity and weak phosphodiesterase activity rather than to enrichment of A1Rs.
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Affiliation(s)
- Douglas A Caruana
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom.,Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, NC, United States
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, NC, United States
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Hill E, Hickman C, Diez R, Wall M. Role of A 1 receptor-activated GIRK channels in the suppression of hippocampal seizure activity. Neuropharmacology 2019; 164:107904. [PMID: 31812775 DOI: 10.1016/j.neuropharm.2019.107904] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 11/12/2019] [Accepted: 12/03/2019] [Indexed: 12/19/2022]
Abstract
The neuromodulator adenosine is released during seizure activity to provide negative feedback suppression of ongoing activity and to delay the occurrence of the next burst of activity. Adenosine acts via multiple G-protein-coupled receptors including the A1 receptor (A1R) which inhibits neurotransmitter release and hyperpolarises neuronal membrane potential. The hyperpolarisation is produced, at least in part, by the activation of G-protein-activated inwardly rectifying K+ (GIRK) channels. We have used tertiapin-Q (TQ), a potent and selective inhibitor of GIRK channels, to assess the role of GIRK channels in controlling seizure activity in areas CA1 and CA2 of mouse hippocampal slices. TQ (100-300 nM) blocked ~50% of the adenosine-mediated membrane potential hyperpolarisation of hippocampal CA1 and CA2 neurons. TQ (100 nM) had no significant effect on synaptic transmission in area CA1 of the hippocampus but enhanced transmission in CA2, an effect prevented by blocking A1Rs. TQ (100 nM) increased the frequency of spontaneous activity (induced by removing Mg2+ and increasing K+) and blunted the effects of exogenous adenosine on the suppression of activity. TQ had a significantly greater effect on electrically-stimulated seizure activity induced in CA2 versus that in CA1, producing a greater increase in both the duration and amplitude of the stimulated bursts. This is consistent with the greater A1R density and A1R activation tone in CA2. Thus GIRK channels play a role in the supressing effects of adenosine on seizure activity.
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Affiliation(s)
- Emily Hill
- School of Life Sciences, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, UK
| | - Charlotte Hickman
- School of Life Sciences, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, UK
| | - Rebecca Diez
- School of Life Sciences, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, UK
| | - Mark Wall
- School of Life Sciences, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, UK.
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10
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Gerber KJ, Dammer EB, Duong DM, Deng Q, Dudek SM, Seyfried NT, Hepler JR. Specific Proteomes of Hippocampal Regions CA2 and CA1 Reveal Proteins Linked to the Unique Physiology of Area CA2. J Proteome Res 2019; 18:2571-2584. [PMID: 31059263 DOI: 10.1021/acs.jproteome.9b00103] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The hippocampus is well established as an essential brain center for learning and memory. Within the hippocampus, recent studies show that area CA2 is important for social memory and is an anomaly compared to its better-understood neighboring region, CA1. Unlike CA1, CA2 displays a lack of typical synaptic plasticity, enhanced calcium buffering and extrusion, and resilience to cell death following injury. Although recent studies have identified multiple molecular markers of area CA2, the proteins that mediate the unique physiology, signaling, and resilience of this region are unknown. Using a transgenic GFP-reporter mouse line that expresses eGFP in CA2, we were able to perform targeted dissections of area CA2 and CA1 for proteomic analysis. We identified over 100 proteins with robustly enriched expression in area CA2 compared to CA1. Many of these proteins, including RGS14 and NECAB2, have already been shown to be enriched in CA2 and important for its function, while many more merit further study in the context of enhanced expression in this enigmatic brain region. Furthermore, we performed a comprehensive analysis of the entire data set (>2300 proteins) using a weighted protein co-expression network analysis. This identified eight distinct co-expressed patterns of protein co-enrichment associated with increased expression in area CA2 tissue (compared to CA1). The novel data set we present here reveals a specific CA2 hippocampal proteome, laying the groundwork for future studies and a deeper understanding of area CA2 and the proteins mediating its unique physiology and signaling.
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Affiliation(s)
- Kyle J Gerber
- Department of Pharmacology and Chemical Biology, Rollins Research Center , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - Eric B Dammer
- Department of Biochemistry , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Center for Neurodegenerative Disease , Emory University , Atlanta , Georgia 30322 , United States
| | - Duc M Duong
- Department of Biochemistry , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Center for Neurodegenerative Disease , Emory University , Atlanta , Georgia 30322 , United States
| | - Qiudong Deng
- Department of Biochemistry , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Center for Neurodegenerative Disease , Emory University , Atlanta , Georgia 30322 , United States
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences , National Institutes of Health , Research Triangle Park , North Carolina 27709 , United States
| | - Nicholas T Seyfried
- Department of Biochemistry , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Center for Neurodegenerative Disease , Emory University , Atlanta , Georgia 30322 , United States.,Department of Neurology , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - John R Hepler
- Department of Pharmacology and Chemical Biology, Rollins Research Center , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
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