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Meloni EG, Carlezon WA, Bolshakov VY. Association between social dominance hierarchy and PACAP expression in the extended amygdala, corticosterone, and behavior in C57BL/6 male mice. Sci Rep 2024; 14:8919. [PMID: 38637645 PMCID: PMC11026503 DOI: 10.1038/s41598-024-59459-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 04/10/2024] [Indexed: 04/20/2024] Open
Abstract
The natural alignment of animals into social dominance hierarchies produces adaptive, and potentially maladaptive, changes in the brain that influence health and behavior. Aggressive and submissive behaviors assumed by animals through dominance interactions engage stress-dependent neural and hormonal systems that have been shown to correspond with social rank. Here, we examined the association between social dominance hierarchy status established within cages of group-housed mice and the expression of the stress peptide PACAP in the bed nucleus of the stria terminalis (BNST) and central nucleus of the amygdala (CeA). We also examined the relationship between social dominance rank and blood corticosterone (CORT) levels, body weight, motor coordination (rotorod) and acoustic startle. Male C57BL/6 mice were ranked as either Dominant, Submissive, or Intermediate based on counts of aggressive/submissive encounters assessed at 12 weeks-old following a change in homecage conditions. PACAP expression was significantly higher in the BNST, but not the CeA, of Submissive mice compared to the other groups. CORT levels were lowest in Submissive mice and appeared to reflect a blunted response following events where dominance status is recapitulated. Together, these data reveal changes in specific neural/neuroendocrine systems that are predominant in animals of lowest social dominance rank, and implicate PACAP in brain adaptations that occur through the development of social dominance hierarchies.
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Affiliation(s)
- Edward G Meloni
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA, 02478, USA.
- McLean Hospital, Mailman Research Center, 115 Mill St., Belmont, MA, 02478, USA.
| | - William A Carlezon
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA, 02478, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA, 02478, USA
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Ross RA, Kim A, Das P, Li Y, Choi YK, Thompson AT, Douglas E, Subramanian S, Ramos K, Callahan K, Bolshakov VY, Ressler KJ. Prefrontal cortex melanocortin 4 receptors (MC4R) mediate food intake behavior in male mice. Physiol Behav 2023; 269:114280. [PMID: 37369302 PMCID: PMC10528493 DOI: 10.1016/j.physbeh.2023.114280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 06/29/2023]
Abstract
BACKGROUND Melanocortin 4 receptor (MC4R) activity in the hypothalamus is crucial for regulation of metabolism and food intake. The peptide ligands for the MC4R are associated with feeding, energy expenditure, and also with complex behaviors that orchestrate energy intake and expenditure, but the downstream neuroanatomical and neurochemical targets associated with these behaviors are elusive. In addition to strong expression in the hypothalamus, the MC4R is highly expressed in the medial prefrontal cortex, a region involved in executive function and decision-making. METHODS Using viral techniques in genetically modified male mice combined with molecular techniques, we identify and define the effects on feeding behavior of a novel population of MC4R expressing neurons in the infralimbic (IL) region of the cortex. RESULTS Here, we describe a novel population of MC4R-expressing neurons in the IL of the mouse prefrontal cortex that are glutamatergic, receive input from melanocortinergic neurons, and project to multiple regions that coordinate appetitive responses to food-related stimuli. The neurons are stimulated by application of MC4R-specific peptidergic agonist, THIQ. Deletion of MC4R from the IL neurons causes increased food intake and body weight gain and impaired executive function in simple food-related behavior tasks. CONCLUSION Together, these data suggest that MC4R neurons of the IL play a critical role in the regulation of food intake in male mice.
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Affiliation(s)
- Rachel A Ross
- Departments of Neuroscience and Psychiatry, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Psychiatry, McLean Hospital, Boston, MA, USA.
| | - Angela Kim
- Department of Endocrinology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Priyanka Das
- Departments of Neuroscience and Psychiatry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Yan Li
- Department of Psychiatry, McLean Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | | | | | | | | | - Kat Ramos
- Northeastern University, Boston, MA, USA
| | - Kathryn Callahan
- Departments of Neuroscience and Psychiatry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Kerry J Ressler
- Department of Psychiatry, McLean Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
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Kambali M, Li Y, Unichenko P, Pliego JF, Yadav R, Liu J, McGuinness P, Cobb JG, Wang M, Nagarajan R, Lyu J, Vongsouthi V, Jackson CJ, Engin E, Coyle JT, Shin J, Talkowski ME, Homanics GE, Bolshakov VY, Henneberger C, Rudolph U. A marker chromosome in psychosis identifies glycine decarboxylase (GLDC) as a novel regulator of neuronal and synaptic function in the hippocampus. bioRxiv 2023:2023.05.29.542745. [PMID: 37398055 PMCID: PMC10312439 DOI: 10.1101/2023.05.29.542745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The biological significance of a small supernumerary marker chromosome that results in dosage alterations to chromosome 9p24.1, including triplication of the GLDC gene encoding glycine decarboxylase, in two patients with psychosis is unclear. In an allelic series of copy number variant mouse models, we identify that triplication of Gldc reduces extracellular glycine levels as determined by optical fluorescence resonance energy transfer (FRET) in dentate gyrus (DG) but not in CA1, suppresses long-term potentiation (LTP) in mPP-DG synapses but not in CA3-CA1 synapses, reduces the activity of biochemical pathways implicated in schizophrenia and mitochondrial bioenergetics, and displays deficits in prepulse inhibition, startle habituation, latent inhibition, working memory, sociability and social preference. Our results thus provide a link between a genomic copy number variation, biochemical, cellular and behavioral phenotypes, and further demonstrate that GLDC negatively regulates long-term synaptic plasticity at specific hippocampal synapses, possibly contributing to the development of neuropsychiatric disorders.
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Meloni EG, Carlezon WA, Bolshakov VY. Impact of social dominance hierarchy on PACAP expression in the extended amygdala, corticosterone, and behavior in C57BL/6 male mice. bioRxiv 2023:2023.05.03.539254. [PMID: 37205328 PMCID: PMC10187259 DOI: 10.1101/2023.05.03.539254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The natural alignment of animals into social dominance hierarchies produces adaptive, and potentially maladaptive, changes in the brain that influence health and behavior. Aggressive and submissive behaviors assumed by animals through dominance interactions engage stress-dependent neural and hormonal systems that have been shown to correspond with social rank. Here, we examined the impact of social dominance hierarchies established within cages of group-housed laboratory mice on expression of the stress peptide pituitary adenylate cyclase-activating polypeptide (PACAP) in areas of the extended amygdala comprising the bed nucleus of the stria terminalis (BNST) and central nucleus of the amygdala (CeA). We also quantified the impact of dominance rank on corticosterone (CORT), body weight, and behavior including rotorod and acoustic startle response. Weight-matched male C57BL/6 mice, group-housed (4/cage) starting at 3 weeks of age, were ranked as either most-dominant (Dominant), least-dominant (Submissive) or in-between rank (Intermediate) based on counts of aggressive and submissive encounters assessed at 12 weeks-old following a change in homecage conditions. We found that PACAP expression was significantly higher in the BNST, but not the CeA, of Submissive mice compared to the other two groups. CORT levels were lowest in Submissive mice and appeared to reflect a blunted response following social dominance interactions. Body weight, motor coordination, and acoustic startle were not significantly different between the groups. Together, these data reveal changes in specific neural/neuroendocrine systems that are predominant in animals of lowest social dominance rank, and implicate PACAP in brain adaptations that occur through the development of social dominance hierarchies.
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Affiliation(s)
- Edward G. Meloni
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA 02478
| | - William A. Carlezon
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA 02478
| | - Vadim Y. Bolshakov
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA 02478
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Li Y, Andero R, Luchkina NV, Suh J, Ross RA, Lowell BB, Carlezon WA, Ressler KJ, Bolshakov VY. PACAP-mediated gating of anxiety-controlling circuits. bioRxiv 2023:2023.05.01.539007. [PMID: 37205515 PMCID: PMC10187154 DOI: 10.1101/2023.05.01.539007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Combining the use of ex vivo and in vivo optogenetics, viral tracing, electrophysiology and behavioral testing, we show that the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) gates anxiety-controlling circuits by differentially affecting synaptic efficacy at projections from the basolateral amygdala (BLA) to two different subdivisions of the dorsal subdivision of the bed nucleus of the stria terminalis (BNST), modifying the signal flow in BLA-ovBNST-adBNST circuits in such a way that adBNST is inhibited. Inhibition of adBNST is translated into the reduced firing probability of adBNST neurons during afferent activation, explaining the anxiety-triggering actions of PACAP in BNST, as inhibition of adBNST is anxiogenic. Our results reveal how innate, fear-related behavioral mechanisms may be controlled by neuropeptides, PACAP specifically, at the level of underlying neural circuits by inducing long-lasting plastic changes in functional interactions between their different structural components.
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Yu Y, Jiang H, Liang Q, Qiu L, Huang T, Hu H, Bolshakov VY, Perlmutter JS, Tu Z. Radiosynthesis and Evaluation of a C-11 Radiotracer for Transient Receptor Potential Canonical 5 in the Brain. Mol Imaging Biol 2023; 25:334-342. [PMID: 35951211 PMCID: PMC9918595 DOI: 10.1007/s11307-022-01760-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/12/2022] [Accepted: 07/14/2022] [Indexed: 10/15/2022]
Abstract
PURPOSE TRPC5 belongs to the mammalian superfamily of transient receptor potential (TRP) Ca2+-permeable cationic channels and it has been implicated in various CNS disorders. As part of our ongoing interest in the development of a PET radiotracer for imaging TRPC5, herein, we explored the radiosynthesis, and in vitro and in vivo evaluation of a new C-11 radiotracer [11C]HC070 in rodents and nonhuman primates. PROCEDURES [11C]HC070 was radiolabeled utilizing the corresponding precursor and [11C]CH3I via N-methylation protocol. Ex vivo biodistribution study of [11C]HC070 was performed in Sprague-Dawley rats. In vitro autoradiography study was conducted for the rat brain sections to characterize the radiotracer distribution in the brain regionals. MicroPET brain imaging studies of [11C]HC070 were done for 129S1/SvImJ wild-type mice and 129S1/SvImJ TRPC5 knockout mice for 0-60-min dynamic data acquisition after intravenous administration of the radiotracer. Dynamic PET scans (0-120 min) for the brain of cynomolgus male macaques were performed after the radiotracer injection. RESULTS [11C]HC070 was efficiently prepared with good radiochemical yield (45 ± 5%, n = 15), high chemical and radiochemical purity (> 99%), and high molar activity (320.6 ± 7.4 GBq/μmol, 8.6 ± 0.2 Ci/μmol) at the end of bombardment (EOB). Radiotracer [11C]HC070 has good solubility in the aqueous dose solution. The ex vivo biodistribution study showed that [11C]HC070 had a quick rat brain clearance. Autoradiography demonstrated that [11C]HC070 specifically binds to TRPC5-enriched regions in rat brain. MicroPET study showed the peak brain uptake (SUV value) was 0.63 in 129S1/SvImJ TRPC5 knockout mice compared to 1.13 in 129S1/SvImJ wild-type mice. PET study showed that [11C]HC070 has good brain uptake with maximum SUV of ~ 2.2 in the macaque brain, followed by rapid clearance. CONCLUSIONS Our data showed that [11C]HC070 is a TRPC5-specific radiotracer with high brain uptake and good brain washout pharmacokinetics in both rodents and nonhuman primates. The radiotracer is worth further investigating of its suitability to be a PET radiotracer for imaging TRPC5 in animals and human subjects in vivo.
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Affiliation(s)
- Yanbo Yu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hao Jiang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Qianwa Liang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Lin Qiu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tianyu Huang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hongzhen Hu
- Center for the Study of Itch and Sensory Disorders, Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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Abstract
Mutations in the Presenilin genes (PSEN1 and PSEN2) are the major cause of familial Alzheimer's disease (AD), highlighting the importance of Presenilin (PS) in AD pathogenesis. Previous studies of PS function in the hippocampus demonstrated that loss of PS results in the impairment of short- and long-term synaptic plasticity and neurotransmitter release at hippocampal Schaffer collateral (SC) and mossy fiber (MF) synapses. Cortical input to the hippocampus through the lateral perforant pathway (LPP) and the medial perforant pathway (MPP) is critical for normal cognitive functions and is particularly vulnerable during aging and early stages of AD. Whether PS regulates synaptic function in the perforant pathways, however, remained unknown. In the current study, we investigate PS function in the LPP and MPP by performing whole-cell and field-potential electrophysiological recordings using acute hippocampal slices from postnatal forebrain-restricted excitatory neuron-specific PS conditional double knockout (cDKO) mice. We found that paired-pulse ratio (PPR) is reduced in the LPP and MPP of PS cDKO mice. Moreover, synaptic frequency facilitation or depression in the LPP or MPP, respectively, is impaired in PS cDKO mice. Notably, depletion of intracellular Ca2+ stores by inhibition of sarcoendoplasmic reticulum Ca2+ ATPase (SERCA) minics and occludes the effects of PS inactivation, as evidenced by decreases of the evoked excitatory postsynaptic currents (EPSCs) amplitude in the LPP and MPP of control neurons but no effect on the EPSC amplitude in PS cDKO neurons, suggesting that impaired intracellular calcium homeostasis in the absence of PS may contribute to the observed deficits in synaptic transmission. While spontaneous synaptic events, such as both the frequency and the amplitude of spontaneous or miniature EPSCs, are similar between PS cDKO and control neurons, long-term potentiation (LTP) is impaired in the LPP and MPP of PS cDKO mice, accompanied with reduction of evoked NMDA receptor-mediated responses. These findings show the importance of PS in the regulation of synaptic plasticity and intracellular calcium homeostasis in the hippocampal perforant pathways.
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Affiliation(s)
- Sang Hun Lee
- Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
| | - Jie Shen
- Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
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Ressler KJ, Berretta S, Bolshakov VY, Rosso IM, Meloni EG, Rauch SL, Carlezon WA. Post-traumatic stress disorder: clinical and translational neuroscience from cells to circuits. Nat Rev Neurol 2022; 18:273-288. [PMID: 35352034 PMCID: PMC9682920 DOI: 10.1038/s41582-022-00635-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2022] [Indexed: 01/16/2023]
Abstract
Post-traumatic stress disorder (PTSD) is a maladaptive and debilitating psychiatric disorder, characterized by re-experiencing, avoidance, negative emotions and thoughts, and hyperarousal in the months and years following exposure to severe trauma. PTSD has a prevalence of approximately 6-8% in the general population, although this can increase to 25% among groups who have experienced severe psychological trauma, such as combat veterans, refugees and victims of assault. The risk of developing PTSD in the aftermath of severe trauma is determined by multiple factors, including genetics - at least 30-40% of the risk of PTSD is heritable - and past history, for example, prior adult and childhood trauma. Many of the primary symptoms of PTSD, including hyperarousal and sleep dysregulation, are increasingly understood through translational neuroscience. In addition, a large amount of evidence suggests that PTSD can be viewed, at least in part, as a disorder that involves dysregulation of normal fear processes. The neural circuitry underlying fear and threat-related behaviour and learning in mammals, including the amygdala-hippocampus-medial prefrontal cortex circuit, is among the most well-understood in behavioural neuroscience. Furthermore, the study of threat-responding and its underlying circuitry has led to rapid progress in understanding learning and memory processes. By combining molecular-genetic approaches with a translational, mechanistic knowledge of fear circuitry, transformational advances in the conceptual framework, diagnosis and treatment of PTSD are possible. In this Review, we describe the clinical features and current treatments for PTSD, examine the neurobiology of symptom domains, highlight genomic advances and discuss translational approaches to understanding mechanisms and identifying new treatments and interventions for this devastating syndrome.
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Affiliation(s)
- Kerry J Ressler
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA.
| | - Sabina Berretta
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - Vadim Y Bolshakov
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - Isabelle M Rosso
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - Edward G Meloni
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - Scott L Rauch
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - William A Carlezon
- SPARED Center, Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
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Lee SH, Bolshakov VY, Shen J. Inactivation of Presenilin in inhibitory neurons results in decreased GABAergic responses and enhanced synaptic plasticity. Mol Brain 2021; 14:85. [PMID: 34034776 PMCID: PMC8152317 DOI: 10.1186/s13041-021-00796-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 05/18/2021] [Indexed: 11/10/2022] Open
Abstract
Mutations in the Presenilin genes are the major genetic cause of Alzheimer's disease (AD). Presenilin (PS) is highly expressed in the hippocampus, which is particularly vulnerable in AD. Previous studies of PS function in the hippocampus, however, focused exclusively on excitatory neurons. Whether PS regulates inhibitory neuronal function remained unknown. In the current study, we investigate PS function in GABAergic neurons by performing whole-cell and field-potential electrophysiological recordings using acute hippocampal slices from inhibitory neuron-specific PS conditional double knockout (IN-PS cDKO) mice at 2 months of age, before the onset of age-dependent loss of interneurons. We found that the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) is reduced in hippocampal CA1 neurons of IN-PS cDKO mice, whereas the amplitude of sIPSCs is normal. Moreover, the efficacy of inhibitory neurotransmission as assessed with synaptic input/output relations for evoked mono- and di-synaptic IPSCs is markedly lowered in hippocampal CA1 neurons of IN-PS cDKO mice. Consistent with these findings, IN-PS cDKO mice display enhanced paired-pulse facilitation, frequency facilitation and long-term potentiation in the Schaffer collateral-CA1 pathway. Interestingly, depletion of intracellular Ca2+ stores by inhibition of sarcoendoplasmic reticulum Ca2+ ATPase results in a reduction of IPSC amplitude in control hippocampal neurons but not in IN-PS cDKO neurons, suggesting that impaired intracellular calcium homeostasis in the absence of PS may contribute to the deficiencies in inhibitory neurotransmission. Furthermore, the amplitude of IPSCs induced by short trains of presynaptic stimulation and paired-pulse ratio are decreased in IN-PS cDKO mice. These findings show that inactivation of PS in interneurons results in decreased GABAergic responses and enhanced synaptic plasticity in the hippocampus, providing additional evidence for the importance of PS in the regulation of synaptic plasticity and calcium homeostasis.
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Affiliation(s)
- Sang Hun Lee
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
| | - Jie Shen
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
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Lee SH, Kang J, Ho A, Watanabe H, Bolshakov VY, Shen J. APP Family Regulates Neuronal Excitability and Synaptic Plasticity but Not Neuronal Survival. Neuron 2020; 108:676-690.e8. [PMID: 32891188 PMCID: PMC7704911 DOI: 10.1016/j.neuron.2020.08.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 01/03/2023]
Abstract
Amyloid precursor protein (APP) is associated with both familial and sporadic forms of Alzheimer's disease. Despite its importance, the role of APP family in neuronal function and survival remains unclear because of perinatal lethality exhibited by knockout mice lacking all three APP family members. Here we report that selective inactivation of APP family members in excitatory neurons of the postnatal forebrain results in neither cortical neurodegeneration nor increases in apoptosis and gliosis up to ∼2 years of age. However, hippocampal synaptic plasticity, learning, and memory are impaired in these mutant mice. Furthermore, hippocampal neurons lacking APP family exhibit hyperexcitability, as evidenced by increased neuronal spiking in response to depolarizing current injections, whereas blockade of Kv7 channels mimics and largely occludes the effects of APP family inactivation. These findings demonstrate that APP family is not required for neuronal survival and suggest that APP family may regulate neuronal excitability through Kv7 channels.
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Affiliation(s)
- Sang Hun Lee
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jongkyun Kang
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angela Ho
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hirotaka Watanabe
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Jie Shen
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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11
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Song B, Cha Y, Ko S, Jeon J, Lee N, Seo H, Park KJ, Lee IH, Lopes C, Feitosa M, Luna MJ, Jung JH, Kim J, Hwang D, Cohen BM, Teicher MH, Leblanc P, Carter BS, Kordower JH, Bolshakov VY, Kong SW, Schweitzer JS, Kim KS. Human autologous iPSC-derived dopaminergic progenitors restore motor function in Parkinson's disease models. J Clin Invest 2020; 130:904-920. [PMID: 31714896 DOI: 10.1172/jci130767] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder associated with loss of striatal dopamine, secondary to degeneration of midbrain dopamine (mDA) neurons in the substantia nigra, rendering cell transplantation a promising therapeutic strategy. To establish human induced pluripotent stem cell-based (hiPSC-based) autologous cell therapy, we report a platform of core techniques for the production of mDA progenitors as a safe and effective therapeutic product. First, by combining metabolism-regulating microRNAs with reprogramming factors, we developed a method to more efficiently generate clinical-grade iPSCs, as evidenced by genomic integrity and unbiased pluripotent potential. Second, we established a "spotting"-based in vitro differentiation methodology to generate functional and healthy mDA cells in a scalable manner. Third, we developed a chemical method that safely eliminates undifferentiated cells from the final product. Dopaminergic cells thus express high levels of characteristic mDA markers, produce and secrete dopamine, and exhibit electrophysiological features typical of mDA cells. Transplantation of these cells into rodent models of PD robustly restores motor function and reinnervates host brain, while showing no evidence of tumor formation or redistribution of the implanted cells. We propose that this platform is suitable for the successful implementation of human personalized autologous cell therapy for PD.
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Affiliation(s)
- Bin Song
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Young Cha
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Sanghyeok Ko
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Jeha Jeon
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Nayeon Lee
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Hyemyung Seo
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA.,Department of Molecular and Life Sciences, Hanyang University, Ansan, Korea
| | | | - In-Hee Lee
- Department of Pediatrics.,Computational Health Informatics Program, Boston Children's Hospital, and
| | - Claudia Lopes
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Melissa Feitosa
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - María José Luna
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Jin Hyuk Jung
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Jisun Kim
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA.,Department of Molecular and Life Sciences, Hanyang University, Ansan, Korea
| | - Dabin Hwang
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | | | | | - Pierre Leblanc
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Bob S Carter
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey H Kordower
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | | | - Sek Won Kong
- Department of Pediatrics.,Computational Health Informatics Program, Boston Children's Hospital, and
| | - Jeffrey S Schweitzer
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kwang-Soo Kim
- Department of Psychiatry and.,Molecular Neurobiology Laboratory, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
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12
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Huang CCY, Muszynski KJ, Bolshakov VY, Balu DT. Deletion of Dtnbp1 in mice impairs threat memory consolidation and is associated with enhanced inhibitory drive in the amygdala. Transl Psychiatry 2019; 9:132. [PMID: 30967545 PMCID: PMC6456574 DOI: 10.1038/s41398-019-0465-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 03/23/2019] [Indexed: 11/19/2022] Open
Abstract
Schizophrenia is a severe and highly heritable disorder. Dystrobrevin-binding protein 1 (DTNBP1), also known as dysbindin-1, has been implicated in the pathophysiology of schizophrenia. Specifically, dysbindin-1 mRNA and protein expression are decreased in the brains of subjects with this disorder. Mice lacking dysbinidn-1 also display behavioral phenotypes similar to those observed in schizophrenic patients. However, it remains unknown whether deletion of dysbindin-1 impacts functions of the amygdala, a brain region that is critical for emotional processing, which is disrupted in patients with schizophrenia. Here, we show that dysbindin-1 is expressed in both excitatory and inhibitory neurons of the basolateral amygdala (BLA). Deletion of dysbindin-1 in male mice (Dys-/-) impaired cued and context-dependent threat memory, without changes in measures of anxiety. The behavioral deficits observed in Dys-/- mice were associated with perturbations in the BLA, including the enhancement of GABAergic inhibition of pyramidal neurons, increased numbers of parvalbumin interneurons, and morphological abnormalities of dendritic spines on pyramidal neurons. Our findings highlight an important role for dysbindin-1 in the regulation of amygdalar function and indicate that enhanced inhibition of BLA pyramidal neuron activity may contribute to the weakened threat memory expression observed in Dys-/- mice.
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Affiliation(s)
- Cathy C Y Huang
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA.
- Department of Life Sciences, National Central University, Taoyuan, Taiwan.
| | - Kevin J Muszynski
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
- Cellular Neurobiology laboratory, McLean Hospital, Belmont, MA, USA
| | - Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA.
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13
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Luchkina NV, Bolshakov VY. Diminishing fear: Optogenetic approach toward understanding neural circuits of fear control. Pharmacol Biochem Behav 2018; 174:64-79. [PMID: 28502746 PMCID: PMC5681900 DOI: 10.1016/j.pbb.2017.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/13/2017] [Accepted: 05/10/2017] [Indexed: 02/05/2023]
Abstract
Understanding complex behavioral processes, both learned and innate, requires detailed characterization of the principles governing signal flow in corresponding neural circuits. Previous studies were hampered by the lack of appropriate tools needed to address the complexities of behavior-driving micro- and macrocircuits. The development and implementation of optogenetic methodologies revolutionized the field of behavioral neuroscience, allowing precise spatiotemporal control of specific, genetically defined neuronal populations and their functional connectivity both in vivo and ex vivo, thus providing unprecedented insights into the cellular and network-level mechanisms contributing to behavior. Here, we review recent pioneering advances in behavioral studies with optogenetic tools, focusing on mechanisms of fear-related behavioral processes with an emphasis on approaches which could be used to suppress fear when it is pathologically expressed. We also discuss limitations of these methodologies as well as review new technological developments which could be used in future mechanistic studies of fear behavior.
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Affiliation(s)
- Natalia V Luchkina
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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14
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Lee SH, Lutz D, Mossalam M, Bolshakov VY, Frotscher M, Shen J. Presenilins regulate synaptic plasticity and mitochondrial calcium homeostasis in the hippocampal mossy fiber pathway. Mol Neurodegener 2017; 12:48. [PMID: 28619096 PMCID: PMC5472971 DOI: 10.1186/s13024-017-0189-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/08/2017] [Indexed: 11/24/2022] Open
Abstract
Background Presenilins play a major role in the pathogenesis of Alzheimer’s disease, in which the hippocampus is particularly vulnerable. Previous studies of Presenilin function in the synapse, however, focused exclusively on the hippocampal Schaffer collateral (SC) pathway. Whether Presenilins play similar or distinct roles in other hippocampal synapses is unknown. Methods To investigate the role of Presenilins at mossy fiber (MF) synapses we performed field and whole-cell electrophysiological recordings and Ca2+ imaging using acute hippocampal slices of postnatal forebrain-restricted Presenilin conditional double knockout (PS cDKO) and control mice at 2 months of age. We also performed quantitative electron microscopy (EM) analysis to determine whether mitochondrial content is affected at presynaptic MF boutons of PS cDKO mice. We further conducted behavioral analysis to assess spatial learning and memory of PS cDKO and control mice at 2 months in the Morris water maze. Results We found that long-term potentiation and short-term plasticity, such as paired-pulse and frequency facilitation, are impaired at MF synapses of PS cDKO mice. Moreover, post-tetanic potentiation (PTP), another form of short-term plasticity, is also impaired at MF synapses of PS cDKO mice. Furthermore, blockade of mitochondrial Ca2+ efflux mimics and occludes the PTP deficits at MF synapses of PS cDKO mice, suggesting that mitochondrial Ca2+ homeostasis is impaired in the absence of PS. Quantitative EM analysis showed normal number and area of mitochondria at presynaptic MF boutons of PS cDKO mice, indicating unchanged mitochondrial content. Ca2+ imaging of dentate gyrus granule neurons further revealed that cytosolic Ca2+ increases induced by tetanic stimulation are reduced in PS cDKO granule neurons in acute hippocampal slices, and that inhibition of mitochondrial Ca2+ release during high frequency stimulation mimics and occludes the Ca2+ defects observed in PS cDKO neurons. Consistent with synaptic plasticity impairment observed at MF and SC synapses in acute PS cDKO hippocampal slices, PS cDKO mice exhibit profound spatial learning and memory deficits in the Morris water maze. Conclusions Our findings demonstrate the importance of PS in the regulation of synaptic plasticity and mitochondrial Ca2+ homeostasis in the hippocampal MF pathway.
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Affiliation(s)
- Sang Hun Lee
- Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - David Lutz
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Mohanad Mossalam
- Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA.,Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael Frotscher
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Jie Shen
- Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA. .,Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
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15
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Balu DT, Li Y, Takagi S, Presti KT, Ramikie TS, Rook JM, Jones CK, Lindsley CW, Conn PJ, Bolshakov VY, Coyle JT. An mGlu5-Positive Allosteric Modulator Rescues the Neuroplasticity Deficits in a Genetic Model of NMDA Receptor Hypofunction in Schizophrenia. Neuropsychopharmacology 2016; 41:2052-61. [PMID: 26741285 PMCID: PMC4908650 DOI: 10.1038/npp.2016.2] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/01/2015] [Accepted: 01/02/2016] [Indexed: 12/13/2022]
Abstract
There is substantial evidence that NMDA receptor (NMDAR) hypofunction contributes to the pathophysiology of schizophrenia (SCZ). A recent large-scale genome-wide association study identified serine racemase (SR), the enzyme that produces the NMDAR co-agonist D-serine, as a risk gene for SCZ. Serine racemase knockout (SR-/-) mice, which lack D-serine, exhibit many of the neurochemical and behavioral abnormalities observed in SCZ. Metabotropic glutamate receptor 5 (mGlu5)-positive allosteric modulators (PAMs) are currently being developed to treat cognitive dysfunction. We used in vitro electrophysiology to determine whether the mGlu5 PAM VU0409551 directly enhances NMDAR function in hippocampal slices from adult male SR-/- mice. We administered VU0409551 systemically for 5 days to adult male wild-type C57BL/6 animals to determine the optimal dose to test in SR-/- mice. We used western blot analyses and trace-fear conditioning to determine whether 5 days of VU0409551 treatment could reverse the neuroplasticity and learning deficits, respectively, in SR-/- mice. We show that VU0409551 enhances NMDAR function and rescues long-term potentiation in hippocampal slices obtained from SR-/- mice. Systemic treatment with VU0409551 (10 and 30 mg/kg) to wild-type mice causes a dose-dependent increase in the Akt/GS3Kα/β signaling pathway, which is reduced in SR-/- mice and in SCZ. Furthermore, the administration of VU0409551 to SR-/- mice reverses their deficits in several neuroplasticity signaling pathways and improves their contextual fear memory. These results support positive allosteric modulation of mGlu5, particularly with VU0409551, as a viable mechanism to reverse the deficits in NMDAR function, synaptic plasticity, and memory that are known to be impaired in SCZ.
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Affiliation(s)
- Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA,Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA,Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA, Tel: +617 855 2329, Fax: +617 855 2705, E-mail:
| | - Yan Li
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Shunsuke Takagi
- Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA,Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kendall Taylor Presti
- Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA
| | - Teniel S Ramikie
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jerri M Rook
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Carrie K Jones
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA,Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Joseph T Coyle
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA,Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA
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16
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Engin E, Smith KS, Gao Y, Nagy D, Foster RA, Tsvetkov E, Keist R, Crestani F, Fritschy JM, Bolshakov VY, Hajos M, Heldt SA, Rudolph U. Modulation of anxiety and fear via distinct intrahippocampal circuits. eLife 2016; 5:e14120. [PMID: 26971710 PMCID: PMC4816644 DOI: 10.7554/elife.14120] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 02/24/2016] [Indexed: 11/13/2022] Open
Abstract
Recent findings indicate a high level of specialization at the level of microcircuits and cell populations within brain structures with regards to the control of fear and anxiety. The hippocampus, however, has been treated as a unitary structure in anxiety and fear research despite mounting evidence that different hippocampal subregions have specialized roles in other cognitive domains. Using novel cell-type- and region-specific conditional knockouts of the GABAA receptor α2 subunit, we demonstrate that inhibition of the principal neurons of the dentate gyrus and CA3 via α2-containing GABAA receptors (α2GABAARs) is required to suppress anxiety, while the inhibition of CA1 pyramidal neurons is required to suppress fear responses. We further show that the diazepam-modulation of hippocampal theta activity shows certain parallels with our behavioral findings, suggesting a possible mechanism for the observed behavioral effects. Thus, our findings demonstrate a double dissociation in the regulation of anxiety versus fear by hippocampal microcircuitry. DOI:http://dx.doi.org/10.7554/eLife.14120.001 Fear and anxiety can be thought of as different but related emotional states. Fear is triggered by specific harmful situations, such as the immediate presence of a predator. Anxiety instead results from the possibility of an obscure threat, such as being in an exposed environment, which increases the chance of being detected by a predator. Evidence suggests that slightly different areas of the brain control fear and anxiety, but much remains unknown about the specific brain regions that help to regulate these two emotional states. One brain region that has been implicated in both anxiety and fear – as well as in learning and memory – is the hippocampus. Named after the Greek word for seahorse because of its shape, the hippocampus is made up of three subregions: CA1, CA3 and the dentate gyrus. Each of these subregions has a distinct role in learning and memory. However, their individual contributions to the control of fear and anxiety were not known. An inhibitory receptor protein found in the surface of some hippocampal neurons had previously been shown to be involved in controlling fear and anxiety. Now, Engin et al. have studied three different groups of genetically modified mice, each of which lacks the receptor protein in a different subregion of the hippocampus. The mice completed tests that stimulated anxiety or fear, some while under the influence of the anxiety and fear-reducing drug diazepam. Notably, diazepam failed to reduce fear in animals that lacked the inhibitory receptor protein in the CA1 subregion of the hippocampus, suggesting that this subregion participates in the fear response. However, mice that lacked the receptor in the dentate gyrus or CA3 responded normally to the drug (they showed reduced fear when given diazepam). In tests of anxiety, the picture was exactly the opposite. Diazepam failed to reduce anxiety in animals lacking the inhibitory receptor in the dentate gyrus or CA3, indicating that these subregions are involved in the regulation of anxiety. However, the drug still reduced anxiety in mice that lacked the receptor protein in the CA1 subregion. Further studies are now needed to clarify how manipulating specific subregions of the hippocampus alters how it communicates with other brain structures to generate changes in anxiety or fear-related behaviors. DOI:http://dx.doi.org/10.7554/eLife.14120.002
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Affiliation(s)
- Elif Engin
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, United States.,Department of Psychiatry, Harvard Medical School, Boston, United States
| | - Kiersten S Smith
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, United States.,Department of Psychiatry, Harvard Medical School, Boston, United States
| | - Yudong Gao
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, United States
| | - David Nagy
- Section of Comparative Medicine, Yale School of Medicine, New Haven, United States
| | - Rachel A Foster
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, United States.,Department of Psychiatry, Harvard Medical School, Boston, United States
| | - Evgeny Tsvetkov
- Department of Psychiatry, Harvard Medical School, Boston, United States.,Cellular Neurobiology Laboratory, McLean Hospital, Belmont, United States.,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Ruth Keist
- Institute for Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Florence Crestani
- Institute for Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Jean-Marc Fritschy
- Institute for Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Vadim Y Bolshakov
- Department of Psychiatry, Harvard Medical School, Boston, United States.,Cellular Neurobiology Laboratory, McLean Hospital, Belmont, United States
| | - Mihaly Hajos
- Section of Comparative Medicine, Yale School of Medicine, New Haven, United States
| | - Scott A Heldt
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, United States
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, United States.,Department of Psychiatry, Harvard Medical School, Boston, United States
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17
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Xia D, Watanabe H, Wu B, Lee SH, Li Y, Tsvetkov E, Bolshakov VY, Shen J, Kelleher RJ. Presenilin-1 knockin mice reveal loss-of-function mechanism for familial Alzheimer's disease. Neuron 2015; 85:967-81. [PMID: 25741723 DOI: 10.1016/j.neuron.2015.02.010] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/30/2014] [Accepted: 02/04/2015] [Indexed: 12/15/2022]
Abstract
Presenilins play essential roles in memory formation, synaptic function, and neuronal survival. Mutations in the Presenilin-1 (PSEN1) gene are the major cause of familial Alzheimer's disease (FAD). How PSEN1 mutations cause FAD is unclear, and pathogenic mechanisms based on gain or loss of function have been proposed. Here, we generated Psen1 knockin (KI) mice carrying the FAD mutation L435F or C410Y. Remarkably, KI mice homozygous for either mutation recapitulate the phenotypes of Psen1(-/-) mice. Neither mutation altered Psen1 mRNA expression, but both abolished γ-secretase activity. Heterozygosity for the KI mutation decreased production of Aβ40 and Aβ42, increased the Aβ42/Aβ40 ratio, and exacerbated Aβ deposition. Furthermore, the L435F mutation impairs hippocampal synaptic plasticity and memory and causes age-dependent neurodegeneration in the aging cerebral cortex. Collectively, our findings reveal that FAD mutations can cause complete loss of Presenilin-1 function in vivo, suggesting that clinical PSEN mutations produce FAD through a loss-of-function mechanism.
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Affiliation(s)
- Dan Xia
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Center for Human Genetic Research, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Hirotaka Watanabe
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bei Wu
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sang Hun Lee
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yan Li
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA
| | - Evgeny Tsvetkov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Jie Shen
- Center for Neurologic Diseases, Department of Neurology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| | - Raymond J Kelleher
- Center for Human Genetic Research, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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18
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Kim TG, Yao R, Monnell T, Cho JH, Vasudevan A, Koh A, Peeyush KT, Moon M, Datta D, Bolshakov VY, Kim KS, Chung S. Efficient specification of interneurons from human pluripotent stem cells by dorsoventral and rostrocaudal modulation. Stem Cells 2015; 32:1789-804. [PMID: 24648391 DOI: 10.1002/stem.1704] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 02/14/2014] [Indexed: 12/14/2022]
Abstract
GABAergic interneurons regulate cortical neural networks by providing inhibitory inputs, and their malfunction, resulting in failure to intricately regulate neural circuit balance, is implicated in brain diseases such as Schizophrenia, Autism, and Epilepsy. During early development, GABAergic interneuron progenitors arise from the ventral telencephalic area such as medial ganglionic eminence (MGE) and caudal ganglionic eminence (CGE) by the actions of secreted signaling molecules from nearby organizers, and migrate to their target sites where they form local synaptic connections. In this study, using combinatorial and temporal modulation of developmentally relevant dorsoventral and rostrocaudal signaling pathways (SHH, Wnt, and FGF8), we efficiently generated MGE cells from multiple human pluripotent stem cells. Most importantly, modulation of FGF8/FGF19 signaling efficiently directed MGE versus CGE differentiation. Human MGE cells spontaneously differentiated into Lhx6-expressing GABAergic interneurons and showed migratory properties. These human MGE-derived neurons generated GABA, fired action potentials, and displayed robust GABAergic postsynaptic activity. Transplantation into rodent brains results in well-contained neural grafts enriched with GABAergic interneurons that migrate in the host and mature to express somatostatin or parvalbumin. Thus, we propose that signaling modulation recapitulating normal developmental patterns efficiently generate human GABAergic interneurons. This strategy represents a novel tool in regenerative medicine, developmental studies, disease modeling, bioassay, and drug screening.
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Affiliation(s)
- Tae-Gon Kim
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, Massachusetts, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, Massachusetts, USA
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19
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Cunningham M, Cho JH, Leung A, Savvidis G, Ahn S, Moon M, Lee PKJ, Han JJ, Azimi N, Kim KS, Bolshakov VY, Chung S. hPSC-derived maturing GABAergic interneurons ameliorate seizures and abnormal behavior in epileptic mice. Cell Stem Cell 2014; 15:559-73. [PMID: 25517465 DOI: 10.1016/j.stem.2014.10.006] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/25/2014] [Accepted: 10/16/2014] [Indexed: 01/04/2023]
Abstract
Seizure disorders debilitate more than 65,000,000 people worldwide, with temporal lobe epilepsy (TLE) being the most common form. Previous studies have shown that transplantation of GABA-releasing cells results in suppression of seizures in epileptic mice. Derivation of interneurons from human pluripotent stem cells (hPSCs) has been reported, pointing to clinical translation of quality-controlled human cell sources that can enhance inhibitory drive and restore host circuitry. In this study, we demonstrate that hPSC-derived maturing GABAergic interneurons (mGINs) migrate extensively and integrate into dysfunctional circuitry of the epileptic mouse brain. Using optogenetic approaches, we find that grafted mGINs generate inhibitory postsynaptic responses in host hippocampal neurons. Importantly, even before acquiring full electrophysiological maturation, grafted neurons were capable of suppressing seizures and ameliorating behavioral abnormalities such as cognitive deficits, aggressiveness, and hyperactivity. These results provide support for the potential of hPSC-derived mGIN for restorative cell therapy for epilepsy.
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Affiliation(s)
- Miles Cunningham
- Laboratory for Neural Reconstruction, Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Jun-Hyeong Cho
- Cellular Neurobiology Laboratory, Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Amanda Leung
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - George Savvidis
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Sandra Ahn
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Minho Moon
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Paula K J Lee
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Jason J Han
- MRC Electron and Light Microscopy Core Facility, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Nima Azimi
- Laboratory for Neural Reconstruction, Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Kwang-Soo Kim
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Vadim Y Bolshakov
- Cellular Neurobiology Laboratory, Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Sangmi Chung
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA; Harvard Stem Cell Institute, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA.
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20
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Abstract
Retrieval of fear extinction memory is associated with increased firing of neurons in the medial prefrontal cortex (mPFC). It is unknown, however, how extinction learning-induced changes in mPFC activity are relayed to target structures in the amygdala, resulting in diminished fear responses. Here, we show that fear extinction decreases the efficacy of excitatory synaptic transmission in projections from the mPFC to the basolateral nucleus of the amygdala (BLA), whereas inhibitory responses are not altered. In contrast, synaptic strength at direct mPFC inputs to intercalated neurons remains unchanged after extinction. Moreover, priming stimulation of mPFC projections induced heterosynaptic inhibition in auditory cortical inputs to the BLA. These synaptic mechanisms could contribute to the encoding of extinction memory by diminishing the ability of projections from the mPFC to drive BLA activity while retaining the ability of intercalated neurons to inhibit the output nuclei of the amygdala.
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Affiliation(s)
- Jun-Hyeong Cho
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA
| | - Karl Deisseroth
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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21
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Gisabella B, Bolshakov VY, Benes FM. Kainate receptor-mediated modulation of hippocampal fast spiking interneurons in a rat model of schizophrenia. PLoS One 2012; 7:e32483. [PMID: 22396770 PMCID: PMC3291556 DOI: 10.1371/journal.pone.0032483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 01/31/2012] [Indexed: 12/04/2022] Open
Abstract
Kainate receptor (KAR) subunits are believed to be involved in abnormal GABAergic neurotransmission in the hippocampus (HIPP) in schizophrenia (SZ) and bipolar disorder. Postmortem studies have shown changes in the expression of the GluR5/6 subunits of KARs in the stratum oriens (SO) of sectors CA2/3, where the basolateral amygdala (BLA) sends a robust projection. Previous work using a rat model of SZ demonstrated that BLA activation leads to electrophysiological changes in fast-spiking interneurons in SO of CA2/3. The present study explores KAR modulation of interneurons in CA2/3 in response to BLA activation. Intrinsic firing properties of these interneurons through KAR-mediated activity were measured with patch-clamp recordings from rats that received 15 days of picrotoxin infusion into the BLA. Chronic BLA activation induced changes in the firing properties of CA2/3 interneurons associated with modifications in the function of KARs. Specifically, the responsiveness of these interneurons to activation of KARs was diminished in picrotoxin-treated rats, while the after-hyperpolarization (AHP) amplitude was increased. In addition, we tested blockers of KAR subunits which have been shown to have altered gene expression in SO sector CA2/3 of SZ subjects. The GluR5 antagonist UBP296 further decreased AP frequency and increased AHP amplitude in picrotoxin-treated rats. Application of the GluR6/7 antagonist NS102 suggested that activation of GluR6/7 KARs may be required to maintain the high firing rates in SO interneurons in the presence of KA. Moreover, the GluR6/7 KAR-mediated signaling may be suppressed in PICRO-treated rats. Our findings indicate that glutamatergic activity from the BLA may modulate the firing properties of CA2/3 interneurons through GluR5 and GluR6/7 KARs. These receptors are expressed in GABAergic interneurons and play a key role in the synchronization of gamma oscillations. Modulation of interneuronal activity through KARs in response to amygdala activation may lead to abnormal oscillatory rhythms reported in SZ subjects.
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Affiliation(s)
- Barbara Gisabella
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, Massachusetts, United States of America
- Department of Psychiatry Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vadim Y. Bolshakov
- Department of Psychiatry Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Francine M. Benes
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, Massachusetts, United States of America
- Department of Psychiatry Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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22
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Benneyworth MA, Li Y, Basu AC, Bolshakov VY, Coyle JT. Cell selective conditional null mutations of serine racemase demonstrate a predominate localization in cortical glutamatergic neurons. Cell Mol Neurobiol 2012; 32:613-24. [PMID: 22362148 DOI: 10.1007/s10571-012-9808-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/19/2012] [Indexed: 11/25/2022]
Abstract
D-serine, which is synthesized by the enzyme serine racemase (SR), is a co-agonist at the N-methyl-D-aspartate receptor (NMDAR). Crucial to an understanding of the signaling functions of D-serine is defining the sites responsible for its synthesis and release. In order to quantify the contributions of astrocytes and neurons to SR and D-serine localization, we used recombinant DNA techniques to effect cell type selective suppression of SR expression in astrocytes (aSRCKO) and in forebrain glutamatergic neurons (nSRCKO). The majority of SR is expressed in neurons: SR expression was reduced by ~65% in nSRCKO cerebral cortex and hippocampus, but only ~15% in aSRCKO as quantified by western blots. In contrast, nSRCKO is associated with only modest decreases in D-serine levels as quantified by HPLC, whereas D-serine levels were unaffected in aSRCKO mice. Liver expression of SR was increased by 35% in the nSRCKO, suggesting a role for peripheral SR in the maintenance of brain D-serine. Electrophysiologic studies of long-term potentiation (LTP) at the Schaffer collateral-CA1 pyramidal neuron synapse revealed no alterations in the aSRCKO mice versus wild-type. LTP induced by a single tetanic stimulus was reduced by nearly 70% in the nSRCKO mice. Furthermore, the mini-excitatory post-synaptic currents mediated by NMDA receptors but not by AMPA receptors were significantly reduced in nSRCKO mice. Our findings indicate that in forebrain, where D-serine appears to be the endogenous co-agonist at NMDA receptors, SR is predominantly expressed in glutamatergic neurons, and co-release of glutamate and D-serine is required for optimal activation of post-synaptic NMDA receptors.
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Abstract
Changes in synaptic strength are believed to underlie learning and memory. We explore the idea that norepinephrine is an essential modulator of memory through its ability to regulate synaptic mechanisms. Emotional arousal leads to activation of the locus coeruleus with the subsequent release of norepineprine in the brain, resulting in the enhancement of memory. Norepinephrine activates both pre- and post-synaptic adrenergic receptors at central synapses with different functional outcomes, depending on the expression pattern of these receptors in specific neural circuitries underlying distinct behavioral processes. We review the evidence for noradrenergic modulation of synaptic plasticity with consideration of how this may contribute to the mechanisms of learning and memory.
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Affiliation(s)
- Keith Tully
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, Massachusetts 02478, USA.
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24
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Riccio A, Li Y, Moon J, Kim KS, Smith KS, Rudolph U, Gapon S, Yao GL, Tsvetkov E, Rodig SJ, Van't Veer A, Meloni EG, Carlezon WA, Bolshakov VY, Clapham DE. Essential role for TRPC5 in amygdala function and fear-related behavior. Cell 2009; 137:761-72. [PMID: 19450521 PMCID: PMC2719954 DOI: 10.1016/j.cell.2009.03.039] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 12/19/2008] [Accepted: 03/02/2009] [Indexed: 11/26/2022]
Abstract
The transient receptor potential channel 5 (TRPC5) is predominantly expressed in the brain where it can form heterotetrameric complexes with TRPC1 and TRPC4 channel subunits. These excitatory, nonselective cationic channels are regulated by G protein, phospholipase C-coupled receptors. Here, we show that TRPC5(-/-) mice exhibit diminished innate fear levels in response to innately aversive stimuli. Moreover, mutant mice exhibited significant reductions in responses mediated by synaptic activation of Group I metabotropic glutamate and cholecystokinin 2 receptors in neurons of the amygdala. Synaptic strength at afferent inputs to the amygdala was diminished in P10-P13 null mice. In contrast, baseline synaptic transmission, membrane excitability, and spike timing-dependent long-term potentiation at cortical and thalamic inputs to the amygdala were largely normal in older null mice. These experiments provide genetic evidence that TRPC5, activated via G protein-coupled neuronal receptors, has an essential function in innate fear.
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Affiliation(s)
- Antonio Riccio
- Department of Cardiology, Howard Hughes Medical Institute, Manton Center for Orphan Disease, Children's Hospital Boston, Boston, MA 02115, USA
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25
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Li Y, Krupa B, Kang JS, Bolshakov VY, Liu G. Glycine site of NMDA receptor serves as a spatiotemporal detector of synaptic activity patterns. J Neurophysiol 2009; 102:578-89. [PMID: 19439669 DOI: 10.1152/jn.91342.2008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Calcium influx associated with the opening of N-methyl-D-aspartate (NMDA) receptor channels is the major signal triggering synaptic and developmental plasticity. Controlling the NMDA receptor function is therefore critical for many functions of the brain. We explored the mechanisms of synaptic activation of the NMDAR glycine site by endogenous coagonist using whole cell voltage-clamp recordings from hippocampal neurons in mixed cultures, containing both neurons and glial cells, and, under more physiological conditions, in hippocampal slices. Here we show that the glycine site of the NMDA receptor at hippocampal synapses, both in culture and acute brain slices, is not saturated by the ambient coagonist concentration and is modulated through activity-dependent coagonist release. Augmentation of the NMDA receptor-mediated synaptic responses by local glutamate-induced coagonist release is spatially restricted and determined by spatiotemporal summation of synaptic events at neighboring synaptic inputs on a single dendritic branch. Therefore different spatiotemporal patterns of presynaptic activity could be translated into different levels of the NMDAR activation in specific afferent projections. These results suggest that the NMDA receptor glycine site may serve as a detector of the spatiotemporal characteristics of presynaptic activity patterns.
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Affiliation(s)
- Yan Li
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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26
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Gisabella B, Cunningham MG, Bolshakov VY, Benes FM. Amygdala-dependent regulation of electrical properties of hippocampal interneurons in a model of schizophrenia. Biol Psychiatry 2009; 65:464-72. [PMID: 19027103 DOI: 10.1016/j.biopsych.2008.09.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 09/11/2008] [Accepted: 09/12/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND Schizophrenia (SZ) involves dysfunction of gamma-aminobutyric acid (GABA)ergic transmission in the hippocampus (HIPP), particularly in sector CA2/3. Previous work using a rodent model of postmortem abnormalities in SZ demonstrated that activation of the basolateral amygdala (BLA) results in decreases of GABA currents in pyramidal neurons of CA2/3 but not CA1. In addition, a decrease of GABA cells has been reported in postmortem studies of the HIPP in SZ. In the present work we tested the hypothesis that BLA activation in this rodent model of SZ leads to changes in the electrical properties of interneurons located in sector CA2/3. METHODS Patch clamp recordings in HIPP slices were performed in rat HIPP slices after 15 days of infusion of picrotoxin into the BLA. The intrinsic and firing properties and hyperpolarization-activated currents (Ih) of interneurons were measured in stratum oriens (SO) of CA2/3 and CA1. RESULTS The BLA activation was associated with a lower resting membrane potential and an increased action potential firing rate in interneurons of CA2/3 but not CA1. Recordings from interneurons further demonstrated an increase of currents associated with hyperpolarization-activated cationic channels (Ih), which help to control neuronal firing rates and oscillatory rhythms. CONCLUSIONS Taken together, these results suggest that the enhanced BLA activity is capable of increasing the excitability of interneurons in SO of CA2/3 and might contribute to GABAergic dysfunction in SZ.
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Affiliation(s)
- Barbara Gisabella
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02478, USA
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27
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Tully K, Li Y, Tsvetkov E, Bolshakov VY. Norepinephrine enables the induction of associative long-term potentiation at thalamo-amygdala synapses. Proc Natl Acad Sci U S A 2007; 104:14146-50. [PMID: 17709755 PMCID: PMC1955781 DOI: 10.1073/pnas.0704621104] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Emotional arousal, linked to a surge of norepinephrine (NE) in the amygdala, leads to creation of stronger and longer-lasting memories. However, little is known about the synaptic mechanisms of such modulatory NE influences. Long-term potentiation (LTP) in auditory inputs to the lateral nucleus of the amygdala was recently linked to the acquisition of fear memory. Therefore we explored whether LTP induction at thalamo-amygdala projections, conveying the acoustic conditioned stimulus information to the amygdala during fear conditioning, is under adrenergic control. Using whole-cell recordings from amygdala slices, we show that NE suppresses GABAergic inhibition of projection neurons in the lateral amygdala and enables the induction of LTP at thalamo-amygdala synapses under conditions of intact GABA(A) receptor-mediated inhibition. Our data indicate that the NE effects on the efficacy of inhibition could result from a decrease in excitability of local circuit interneurons, without direct effects of NE on release machinery of the GABA-containing vesicles or the size of single-quanta postsynaptic GABA(A) receptor-mediated responses. Thus, adrenergic modulation of local interneurons may contribute to the formation of fear memory by gating LTP in the conditioned stimulus pathways.
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Affiliation(s)
- Keith Tully
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478
| | - Yan Li
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478
| | - Evgeny Tsvetkov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478
| | - Vadim Y. Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478
- *To whom correspondence should be addressed. E-mail:
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28
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Abstract
The ERK1/2 MAP kinase (MAPK) signaling pathway is important for the formation of long-term memories. In this issue, Shimizu et al. (2007) provide new insight into the regulation of this pathway by demonstrating that activation of MAP kinase occurs through the calcium-dependent degradation of SCOP (suprachiasmatic nucleus circadian oscillatory protein) by the protease calpain.
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Affiliation(s)
- Vadim Y Bolshakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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29
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Shin RM, Tsvetkov E, Bolshakov VY. Spatiotemporal asymmetry of associative synaptic plasticity in fear conditioning pathways. Neuron 2007; 52:883-96. [PMID: 17145508 PMCID: PMC1764975 DOI: 10.1016/j.neuron.2006.10.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 08/18/2006] [Accepted: 10/02/2006] [Indexed: 10/23/2022]
Abstract
Input-specific long-term potentiation (LTP) in afferent inputs to the amygdala serves an essential function in the acquisition of fear memory. Factors underlying input specificity of synaptic modifications implicated in information transfer in fear conditioning pathways remain unclear. Here we show that the strength of naive synapses in two auditory inputs converging on a single neuron in the lateral nucleus of the amygdala (LA) is only modified when a postsynaptic action potential closely follows a synaptic response. The stronger inhibitory drive in thalamic pathway, as compared with cortical input, hampers the induction of LTP at thalamo-amygdala synapses, contributing to the spatial specificity of LTP in convergent inputs. These results indicate that spike timing-dependent synaptic plasticity in afferent projections to the LA is both temporarily and spatially asymmetric, thus providing a mechanism for the conditioned stimulus discrimination during fear behavior.
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Affiliation(s)
- Ryong-Moon Shin
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, Massachusetts 02478, USA
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30
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Kodirov SA, Takizawa S, Joseph J, Kandel ER, Shumyatsky GP, Bolshakov VY. Synaptically released zinc gates long-term potentiation in fear conditioning pathways. Proc Natl Acad Sci U S A 2006; 103:15218-23. [PMID: 17005717 PMCID: PMC1622803 DOI: 10.1073/pnas.0607131103] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The functional role of releasable Zn2+ in the central nervous system remains unknown. Here we show that zinc transporter 3 (ZnT-3), which maintains a high concentration of Zn2+ in synaptic vesicles and serves as a marker for zinc-containing neurons, is enriched in the lateral nucleus of the amygdala and in the temporal area 3 of the auditory cortex, an area that conveys information about the auditory conditioned stimulus to the lateral nucleus of the amygdala, but not in other conditioned stimulus areas located in the auditory thalamus. Using whole-cell recordings from amygdala slices, we demonstrated that activity-dependent release of chelatable Zn2+ is required for the induction of spike timing-dependent long-term potentiation in cortical input to the amygdala implicated in fear learning. Our data indicate that synaptically released Zn2+ enables long-term potentiation at the cortico-amygdala synapses by depressing feed-forward GABAergic inhibition of principal neurons. This regulatory mechanism, implicating pathway-dependent release of Zn2+, may serve an essential control function in assuring spatial specificity of long-lasting synaptic modifications in the neural circuit of a learned behavior.
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Affiliation(s)
- Sodikdjon A. Kodirov
- *Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478
| | - Shuichi Takizawa
- Department of Genetics, Rutgers University, Piscataway, NJ 08854; and
| | - Jamie Joseph
- Department of Genetics, Rutgers University, Piscataway, NJ 08854; and
| | - Eric R. Kandel
- Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University, New York, NY 10032
- To whom correspondence may be addressed. E-mail:
or
| | | | - Vadim Y. Bolshakov
- *Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478
- To whom correspondence may be addressed. E-mail:
or
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31
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Shumyatsky GP, Malleret G, Shin RM, Takizawa S, Tully K, Tsvetkov E, Zakharenko SS, Joseph J, Vronskaya S, Yin D, Schubart UK, Kandel ER, Bolshakov VY. stathmin, a gene enriched in the amygdala, controls both learned and innate fear. Cell 2006; 123:697-709. [PMID: 16286011 DOI: 10.1016/j.cell.2005.08.038] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 06/17/2005] [Accepted: 08/26/2005] [Indexed: 11/18/2022]
Abstract
Little is known about the molecular mechanisms of learned and innate fear. We have identified stathmin, an inhibitor of microtubule formation, as highly expressed in the lateral nucleus (LA) of the amygdala as well as in the thalamic and cortical structures that send information to the LA about the conditioned (learned fear) and unconditioned stimuli (innate fear). Whole-cell recordings from amygdala slices that are isolated from stathmin knockout mice show deficits in spike-timing-dependent long-term potentiation (LTP). The knockout mice also exhibit decreased memory in amygdala-dependent fear conditioning and fail to recognize danger in innately aversive environments. By contrast, these mice do not show deficits in the water maze, a spatial task dependent on the hippocampus, where stathmin is not normally expressed. We therefore conclude that stathmin is required for the induction of LTP in afferent inputs to the amygdala and is essential in regulating both innate and learned fear.
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Affiliation(s)
- Gleb P Shumyatsky
- Department of Genetics, Rutgers University, Piscataway, New Jersey 08854, USA.
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Abstract
The amygdala plays key roles in several aspects of addiction to drugs of abuse. This brain structure has been implicated in behaviours that reflect drug reward, drug seeking, and the aversive effects of drug withdrawal. Using a model that involves repeated cocaine injections to approximate 'binge' intoxication, we show in rats that during cocaine withdrawal, the impact of rewarding brain stimulation is attenuated, as quantified by alterations in intracranial self-stimulation (ICSS) behaviour. These behavioural signs of withdrawal are accompanied by enhancements of glutamatergic synaptic transmission within the lateral amygdala (LA) that occlude electrically induced long-term potentiation (LTP) in tissue slices. Synaptic enhancements during periods of cocaine withdrawal are mechanistically similar to LTP induced with electrical stimulation in control slices, as both forms of synaptic plasticity involve an increase in glutamate release. These results suggest that mechanisms of LTP within the amygdala are recruited during withdrawal from repeated exposure to cocaine. As such, they raise the possibility that the development and maintenance of addictive behaviours may involve, at least in part, mechanisms of synaptic plasticity within specific amygdala circuits.
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Affiliation(s)
- Ivan Goussakov
- Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, Massachusetts 02478, USA
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33
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Abstract
Long-term synaptic modifications in afferent inputs to the amygdala underlie fear conditioning in animals. Fear conditioning to a single sensory modality does not generalize to other cues, implying that synaptic modifications in fear conditioning pathways are input specific. The mechanisms of pathway specificity of long-term potentiation (LTP) are poorly understood. Here we show that inhibition of glutamate transporters leads to the loss of input specificity of LTP in the amygdala slices, as assessed by monitoring synaptic responses at two independent inputs converging on a single postsynaptic neuron. Diffusion of glutamate ("spillover") from stimulated synapses, paired with postsynaptic depolarization, is sufficient to induce LTP in the heterosynaptic pathway, whereas an enzymatic glutamate scavenger abolishes this effect. These results establish active glutamate uptake as a crucial mechanism maintaining the pathway specificity of LTP in the neural circuitry of fear conditioning.
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Affiliation(s)
- Evgeny Tsvetkov
- McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA 02478, USA
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34
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Abstract
The pathology of schizophrenia is characterized by increased hippocampal activity at baseline and during auditory hallucinations. Animal-model studies in which the flow of activity to the hippocampus is increased through decreased amygdalar GABAergic inhibition have shown alterations of hippocampal circuitry similar to schizophrenia, but the functional importance of this phenomenon remains unclear. We provide evidence of decreased hippocampal feed-forward and tonic GABA-mediated inhibition in this animal model, complementing increased hippocampal activity seen in neuroimaging and postmortem studies. We demonstrate that GABA dysfunction increases long-term potentiation through activation of the cholinergic system, offering a new mechanism for pharmacological strategies of this disorder.
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Affiliation(s)
- Barbara Gisabella
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, MA 02478, USA
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35
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Abstract
Fear conditioning, during which emotional significance is attached to an initially biologically insignificant conditioned stimulus, when such neutral stimulus is paired with an aversive unconditioned stimulus, provides an experimental paradigm that is most commonly used to study fear learning. The amygdala, a sub-cortical nuclear group, is a brain structure critically important for fear conditioning. Recent studies indicate that both fear conditioning-induced neuronal plasticity and LTP at the amygdala synapses share common mechanisms of induction and expression. These findings provide the most direct evidence yet available that the mechanisms of LTP are recruited in the experimental animals during behavioral training and that such mechanisms might be utilized for memory storage.
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Affiliation(s)
- Alexander E Dityatev
- Institute of Neurophysiology and Pathophysiology, University of Hamburg, Hamburg, Germany
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36
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Feinmark SJ, Begum R, Tsvetkov E, Goussakov I, Funk CD, Siegelbaum SA, Bolshakov VY. 12-lipoxygenase metabolites of arachidonic acid mediate metabotropic glutamate receptor-dependent long-term depression at hippocampal CA3-CA1 synapses. J Neurosci 2003; 23:11427-35. [PMID: 14673007 PMCID: PMC6740529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
Arachidonic acid metabolites have been proposed as signaling molecules in hippocampal long-term potentiation (LTP) and long-term depression (LTD) for >15 years. However, the functional role of these molecules remains controversial. Here we used a multidisciplinary biochemical, electrophysiological, and genetic approach to examine the function of the 12-lipoxygenase metabolites of arachidonic acid in long-term synaptic plasticity at CA3-CA1 synapses. We found that the 12-lipoxygenase pathway is required for the induction of metabotropic glutamate receptor-dependent LTD (mGluR-LTD), but is not required for LTP: (1) Hippocampal homogenates were capable of synthesizing the 12-lipoxygenase metabolite of arachidonic acid, 12(S)-hydroxyeicosa-5Z,8Z,10E,14Z-tetraenoic acid (HETE). (2) Stimulation protocols that induce mGluR-LTD lead to a release of 12-(S)-HETE from acute hippocampal slices. (3) A mouse in which the leukocyte-type 12-lipoxygenase (the neuronal isoform) was deleted through homologous recombination was deficient in mGluR-LTD, but showed normal LTP. (4) Pharmacological inhibition of 12-lipoxygenase also blocked induction of mGluR-LTD. (5) Finally, direct application of 12(S)-HPETE, but not 15(S)-HPETE, to hippocampal slices induced a long-term depression of synaptic transmission that mimicked and occluded mGluR-LTD induced by synaptic stimulation. Thus, 12(S)-hydroperoxyeicosa-5Z, 8Z, 10E, 14Z-tetraenoic acid (12(S)-HPETE), a 12-lipoxygenase metabolite of arachidonic acid, satisfies all of the criteria of a messenger molecule that is actively recruited for the induction of mGluR-LTD.
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Affiliation(s)
- Steven J Feinmark
- Department of Pharmacology, Center for Neurobiology and Behavior, Columbia University, New York, New York 10032, USA.
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37
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Hinds HL, Goussakov I, Nakazawa K, Tonegawa S, Bolshakov VY. Essential function of alpha-calcium/calmodulin-dependent protein kinase II in neurotransmitter release at a glutamatergic central synapse. Proc Natl Acad Sci U S A 2003; 100:4275-80. [PMID: 12629219 PMCID: PMC153083 DOI: 10.1073/pnas.0530202100] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A significant fraction of the total calciumcalmodulin-dependent protein kinase II (CaMKII) activity in neurons is associated with synaptic connections and is present in nerve terminals, thus suggesting a role for CaMKII in neurotransmitter release. To determine whether CaMKII regulates neurotransmitter release, we generated and analyzed knockout mice in which the dominant alpha-isoform of CaMKII was specifically deleted from the presynaptic side of the CA3-CA1 hippocampal synapse. Conditional CA3 alpha-CaMKII knockout mice exhibited an unchanged basal probability of neurotransmitter release at CA3-CA1 synapses but showed a significant enhancement in the activity-dependent increase in probability of release during repetitive presynaptic stimulation, as was shown with the analysis of unitary synaptic currents. These data indicate that alpha-CaMKII serves as a negative activity-dependent regulator of neurotransmitter release at hippocampal synapses and maintains synapses in an optimal range of release probabilities necessary for normal synaptic operation.
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Affiliation(s)
- Heather L Hinds
- Howard Hughes Medical Institute, Picower Center for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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38
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Shumyatsky GP, Tsvetkov E, Malleret G, Vronskaya S, Hatton M, Hampton L, Battey JF, Dulac C, Kandel ER, Bolshakov VY. Identification of a signaling network in lateral nucleus of amygdala important for inhibiting memory specifically related to learned fear. Cell 2002; 111:905-18. [PMID: 12526815 DOI: 10.1016/s0092-8674(02)01116-9] [Citation(s) in RCA: 260] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We identified the Grp gene, encoding gastrin-releasing peptide, as being highly expressed both in the lateral nucleus of the amygdala, the nucleus where associations for Pavlovian learned fear are formed, and in the regions that convey fearful auditory information to the lateral nucleus. Moreover, we found that GRP receptor (GRPR) is expressed in GABAergic interneurons of the lateral nucleus. GRP excites these interneurons and increases their inhibition of principal neurons. GRPR-deficient mice showed decreased inhibition of principal neurons by the interneurons, enhanced long-term potentiation (LTP), and greater and more persistent long-term fear memory. By contrast, these mice performed normally in hippocampus-dependent Morris maze. These experiments provide genetic evidence that GRP and its neural circuitry operate as a negative feedback regulating fear and establish a causal relationship between Grpr gene expression, LTP, and amygdala-dependent memory for fear.
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Affiliation(s)
- Gleb P Shumyatsky
- Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
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Tsvetkov E, Carlezon WA, Benes FM, Kandel ER, Bolshakov VY. Fear conditioning occludes LTP-induced presynaptic enhancement of synaptic transmission in the cortical pathway to the lateral amygdala. Neuron 2002; 34:289-300. [PMID: 11970870 DOI: 10.1016/s0896-6273(02)00645-1] [Citation(s) in RCA: 274] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Auditory information critical for fear conditioning, a model of emotional learning, is conveyed to the lateral nucleus of the amygdala via two routes: directly from the medial geniculate nucleus and indirectly from the auditory cortex. Here we show in the cortico-amygdala pathway that learned fear occludes electrically induced long-term potentiation (LTP). Quantal analysis of the expression of LTP in this pathway reveals a significant presynaptic component reflected in an increase in probability of transmitter release. Conditioned fear also is accompanied by the enhancement in transmitter release at this cortico-amygdala synapse. These results indicate that the synaptic projections from the auditory cortex to the lateral amygdala are modified during the acquisition and expression of fear to auditory stimulation, thus further strengthening the proposed link between LTP in the auditory pathways to the amygdala and learned fear.
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Affiliation(s)
- Evgeny Tsvetkov
- McLean Hospital, Department of Psychiatry, Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA
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Bolshakov VY, Carboni L, Cobb MH, Siegelbaum SA, Belardetti F. Dual MAP kinase pathways mediate opposing forms of long-term plasticity at CA3-CA1 synapses. Nat Neurosci 2000; 3:1107-12. [PMID: 11036267 DOI: 10.1038/80624] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although the function of the p42/p44 mitogen-activated protein (MAP) kinase pathway in long-term potentiation at hippocampal CA3-CA1 synapses has been well described, relatively little is known about the importance of the p38 MAP kinase pathway in synaptic plasticity. Here we show that the p38 MAP kinase pathway, a parallel signaling cascade activated by distinct upstream kinases, mediates the induction of metabotropic glutamate receptor-dependent long-term depression at CA3-CA1 synapses. Thus, two parallel MAP kinase pathways contribute to opposing forms of long-term plasticity at a central synapse.
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Affiliation(s)
- V Y Bolshakov
- McLean Hospital, Department of Psychiatry, Harvard Medical School, 115 Mill Street, Belmont, Massachusetts 02478, USA
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Abstract
We have generated mice lacking synaptogyrin I and synaptophysin I to explore the functions of these abundant tyrosine-phosphorylated proteins of synaptic vesicles. Single and double knockout mice were alive and fertile without significant morphological or biochemical changes. Electrophysiological recordings in the hippocampal CA1 region revealed that short-term and long-term synaptic plasticity were severely reduced in the synaptophysin/synaptogyrin double knockout mice. LTP was decreased independent of the induction protocol, suggesting that the defect in LTP was not caused by insufficient induction. Our data show that synaptogyrin I and synaptophysin I perform redundant and essential functions in synaptic plasticity without being required for neurotransmitter release itself.
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Affiliation(s)
- R Janz
- Howard Hughes Medical Institute, The University of Texas Southwestern Medical School, Dallas 75235, USA
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Bolshakov VY, Golan H, Kandel ER, Siegelbaum SA. Recruitment of new sites of synaptic transmission during the cAMP-dependent late phase of LTP at CA3-CA1 synapses in the hippocampus. Neuron 1997; 19:635-51. [PMID: 9331354 DOI: 10.1016/s0896-6273(00)80377-3] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Long-term potentiation at CA3-CA1 hippocampal synapses exhibits an early phase and a late phase, which can be distinguished by their underlying molecular mechanisms. Unlike the early phase, the late phase is dependent on both cAMP and protein synthesis. Quantal analysis of unitary synaptic transmission between a single presynaptic CA3 neuron and a single postsynaptic CA1 neuron suggests that, under certain conditions, the early phase of LTP involves an increase in the probability of release of a single quantum of transmitter from a single presynaptic release site, with no change in the number of quanta that are released or in postsynaptic sensitivity to transmitter. Here, we show that the cAMP-induced late phase of LTP involves an increase in the number of quanta released in response to a single presynaptic action potential, possibly due to an increase in the number of sites of synaptic transmission between a single CA3 and a single CA1 neuron.
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Affiliation(s)
- V Y Bolshakov
- Department of Pharmacology, Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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McMahon HT, Bolshakov VY, Janz R, Hammer RE, Siegelbaum SA, Südhof TC. Synaptophysin, a major synaptic vesicle protein, is not essential for neurotransmitter release. Proc Natl Acad Sci U S A 1996; 93:4760-4. [PMID: 8643476 PMCID: PMC39352 DOI: 10.1073/pnas.93.10.4760] [Citation(s) in RCA: 189] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Synaptophysin (syp I) is a synaptic vesicle membrane protein that constitutes approximately 7% of the total vesicle protein. Multiple lines of evidence implicate syp I in a number of nerve terminal functions. To test these, we have disrupted the murine Syp I gene. Mutant mice lacking syp I were viable and fertile. No changes in the structure and protein composition of the mutant brains were observed except for a decrease in synaptobrevin/VAMP II. Synaptic transmission was normal with no detectable changes in synaptic plasticity or the probability of release. Our data demonstrate that one of the major synaptic vesicle membrane proteins is not essential for synaptic transmission, suggesting that its function is either redundant or that it has a more subtle function not apparent in the assays used.
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Affiliation(s)
- H T McMahon
- Howard Hughes Medical Institute, The University of Texas Southwestern Medical School, Dallas 75235, USA
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Abstract
Long-term depression (LTD) was studied in hippocampal slices from neonatal rats at the synapse between CA3 and CA1 pyramidal neurons. The induction of LTD requires the pairing of Ca2+ influx into the postsynaptic CA1 neuron through voltage-gated calcium channels with activation of metabotropic glutamate receptors. The expression of this LTD is at least partly presynaptic, implying the need for a retrograde messenger. We present evidence that arachidonic acid might serve such a function. Thus, arachidonic acid applications simulate LTD whereas blockade of arachidonic acid release inhibits LTD.
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Affiliation(s)
- V Y Bolshakov
- Department of Pharmacology, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
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Abstract
Developmental changes in rat hippocampal transmitter release and synaptic plasticity were investigated. Recordings from pairs of pyramidal neurons in slices showed that an action potential in a CA3 neuron released only a single quantum of transmitter onto a CA1 neuron. Failures of synaptic transmission reflected probabilistic transmitter release. The probability of release (Pr) was 0.9 in 4- to 8-day-old rats and decreased to less than 0.5 at 2 to 3 weeks. Long-term potentiation (LTP) in 2- to 3-week-old rats was associated with an increase in Pr from a single synaptic site. The high initial Pr in 4- to 8-day-old rats normally occludes the expression of LTP at this stage.
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Affiliation(s)
- V Y Bolshakov
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Abstract
The small GTP-binding protein Rab3A is a Rab family member that is abundant in brain synaptic vesicles. Here we show that mice in which the rab3A gene has been mutated by homologous recombination do not express Rab3A but are viable and fertile. Electrophysiological recordings in hippocampal CA1 pyramidal cells indicate that most of their synaptic parameters are also normal, although synaptic depression after short trains of repetitive stimuli (15-30 stimuli at 14 Hz) is significantly increased. Levels of the Rab3A-binding protein rabphilin are decreased by 70%, but expression of more than 20 other synaptic proteins is unchanged. No compensatory changes were detected in other GTP-binding proteins or in proteins that interact with Rab3. Rab3A thus appears not to be essential for synaptic vesicle exocytosis but to play a role in the recruitment of synaptic vesicles for exocytosis during repetitive stimulation.
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Affiliation(s)
- M Geppert
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235
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Abstract
Long-term depression (LTD) is an activity-dependent decrease in synaptic efficacy that together with its counterpart, long-term potentiation, is thought to be an important cellular mechanism for learning and memory in the mammalian brain. The induction of LTD in hippocampal CA1 pyramidal neurons in neonatal rats is shown to depend on postsynaptic calcium ion entry through L-type voltage-gated calcium channels paired with the activation of metabotropic glutamate receptors. Although induced postsynaptically, LTD is due to a long-term decrease in transmitter release from presynaptic terminals. This suggests that LTD is likely to require the production of a retrograde messenger.
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Affiliation(s)
- V Y Bolshakov
- Department of Pharmacology, Howard Hughes Medical Institute, Columbia University, New York, NY 10032
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