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Long-term depression-associated signaling is required for an in vitro model of NMDA receptor-dependent synapse pruning. Neurobiol Learn Mem 2016; 138:39-53. [PMID: 27794462 DOI: 10.1016/j.nlm.2016.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/20/2016] [Accepted: 10/25/2016] [Indexed: 02/06/2023]
Abstract
Activity-dependent pruning of synaptic contacts plays a critical role in shaping neuronal circuitry in response to the environment during postnatal brain development. Although there is compelling evidence that shrinkage of dendritic spines coincides with synaptic long-term depression (LTD), and that LTD is accompanied by synapse loss, whether NMDA receptor (NMDAR)-dependent LTD is a required step in the progression toward synapse pruning is still unknown. Using repeated applications of NMDA to induce LTD in dissociated rat neuronal cultures, we found that synapse density, as measured by colocalization of fluorescent markers for pre- and postsynaptic structures, was decreased irrespective of the presynaptic marker used, post-treatment recovery time, and the dendritic location of synapses. Consistent with previous studies, we found that synapse loss could occur without apparent net spine loss or cell death. Furthermore, synapse loss was unlikely to require direct contact with microglia, as the number of these cells was minimal in our culture preparations. Supporting a model by which NMDAR-LTD is required for synapse loss, the effect of NMDA on fluorescence colocalization was prevented by phosphatase and caspase inhibitors. In addition, gene transcription and protein translation also appeared to be required for loss of putative synapses. These data support the idea that NMDAR-dependent LTD is a required step in synapse pruning and contribute to our understanding of the basic mechanisms of this developmental process.
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202
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Womer FY, Tang Y, Harms MP, Bai C, Chang M, Jiang X, Wei S, Wang F, Barch DM. Sexual dimorphism of the cerebellar vermis in schizophrenia. Schizophr Res 2016; 176:164-170. [PMID: 27401530 DOI: 10.1016/j.schres.2016.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/17/2016] [Accepted: 06/21/2016] [Indexed: 10/21/2022]
Abstract
Converging lines of evidence implicate structural and functional abnormalities in the cerebellum in schizophrenia (SCZ). The cerebellar vermis is of particular interest given its association with clinical symptoms and cognitive deficits in SCZ and its known connections with cortical regions such as the prefrontal cortex. Prior neuroimaging studies have shown structural and functional abnormalities in the vermis in SCZ. In this study, we examined the cerebellar vermis in 50 individuals with SCZ and 54 healthy controls (HC) using a quantitative volumetric approach. All participants underwent high-resolution structural magnetic resonance imaging (MRI). The vermis was manually traced for each participant, and vermis volumes were computed using semiautomated methods. Volumes for total vermis and vermis subregions (anterior and posterior vermis) were analyzed in the SCZ and HC groups. Significant diagnosis-by-sex interaction effects were found in total vermis and vermis subregion analyses. These effects appeared to be driven by significantly decreased posterior vermis volumes in males with SCZ. Exploratory analyses did not reveal significant effects of clinical variables (FEP status, illness duration, and BPRS total score and subscores) on vermis volumes. The findings herein highlight the presence of neural sex differences in SCZ and the need for considering sex-related factors in studying the disorder.
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Affiliation(s)
- Fay Y Womer
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
| | - Yanqing Tang
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Michael P Harms
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Chuan Bai
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Miao Chang
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Xiaowei Jiang
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Shengnan Wei
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Fei Wang
- Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China; The Brain Imaging Center, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Deanna M Barch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Department of Radiology, Washington University, St. Louis, MO, USA; Department of Psychology, Washington University, St. Louis, MO, USA
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203
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Paliperidone increases spontaneous and evoked firing of mesocortical dopaminergic neurons by activating a hyperpolarization-activated inward current. Schizophr Res 2016; 176:252-258. [PMID: 27435059 DOI: 10.1016/j.schres.2016.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 06/29/2016] [Accepted: 07/04/2016] [Indexed: 11/21/2022]
Abstract
Mesocortical dopaminergic (DA) subtype neurons specifically project to the prefrontal cortex, which is closely related with schizophrenia. Mesocortical DA neurons have unique physiological characteristics that are different from those of mesostriatal and mesolimbic DA neurons. Paliperidone, an atypical antipsychotic, is currently used to treat schizophrenia and has better therapeutic effects than typical antipsychotics. However, the underlying physiological mechanism remains unclear. To explore the effects of paliperidone on mesocortical DA neuron activity, here, we retrogradely labeled these cells with fluorescent microsphere retrobeads, and the electrophysiological changes were recorded in whole-cell recordings in rat midbrain slices with or without paliperidone. The data showed that paliperidone (20μmol/L) increased the spontaneous firing rates of labeled mesocortical neurons (P<0.05). Moreover, paliperidone also increased the frequency of evoked action potentials by current injection stimulation (P<0.05), whereas the accompanying amplitude decreased. Furthermore, to explore the mechanisms of paliperidone's effect, Ih currents were detected, and the results showed that hyperpolarizing voltage pulses evoked instantaneous Ih inward currents and paliperidone increased the maximum Ih current. In addition, paliperidone decreased the spontaneous inhibitory postsynaptic currents. Thus, paliperidone increased the spontaneous and evoked firing of mesocortical neurons, possibly by activating the Ih inward current and reducing the inhibitory synaptic transmission, which provides an underlying mechanism of paliperidone's application in schizophrenia.
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204
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Pershing ML, Phenis D, Valentini V, Pocivavsek A, Lindquist DH, Schwarcz R, Bruno JP. Prenatal kynurenine exposure in rats: age-dependent changes in NMDA receptor expression and conditioned fear responding. Psychopharmacology (Berl) 2016; 233:3725-3735. [PMID: 27527585 PMCID: PMC5808405 DOI: 10.1007/s00213-016-4404-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/02/2016] [Indexed: 10/21/2022]
Abstract
RATIONALE Levels of kynurenic acid (KYNA), an endogenous negative modulator of alpha 7 nicotinic acetylcholine receptors (α7nAChRs) and antagonist at glutamatergic N-methyl-D-aspartate receptors (NMDARs), are elevated in the brain of patients with schizophrenia (SZ). In rats, dietary exposure to KYNA's immediate precursor kynurenine during the last week of gestation produces neurochemical and cognitive deficits in adulthood that resemble those seen in patients with SZ. OBJECTIVES The present experiments examined whether prenatal kynurenine exposure results in age-dependent changes in the kynurenine pathway (KP), expression of selected receptors, and cognitive function. METHODS Pregnant dams were fed unadulterated mash (progeny = ECON) or mash containing kynurenine (100 mg/day; progeny = EKYN) from embryonic day (ED) 15 to 22. Male offspring were assessed as juveniles, i.e., prior to puberty (postnatal day [PD] 32), or as adults (PD70) for brain KYNA levels, α7nAChR and NMDAR gene expression, and performance on a trace fear conditioning (TFC) task. RESULTS KYNA levels were comparable between juvenile ECON and EKYN rats, whereas EKYN adults exhibited a ~3-fold increase in brain KYNA relative to ECONs. NR2A expression was persistently reduced (30-40 %) in EKYN rats at both ages. Compared to ECON adults, there was a 50 % reduction in NR1, and a trend toward decreased α7nAChR expression, in adult EKYN rats. Surprisingly, juvenile EKYN rats performed significantly better in the TFC paradigm than controls, whereas adult EKYN animals showed the predicted deficits. CONCLUSIONS Collectively, our results provide evidence that KP changes in the fetal brain alter neuronal development and cause age-dependent effects on neurochemistry and cognitive performance.
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Affiliation(s)
| | - David Phenis
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | | | - Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Derick H. Lindquist
- Department of Psychology, The Ohio State University, Columbus, OH, USA,Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - John P. Bruno
- Department of Psychology, The Ohio State University, Columbus, OH, USA,Department of Neuroscience, The Ohio State University, Columbus, OH, USA
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205
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Bagasrawala I, Zecevic N, Radonjić NV. N-Methyl D-Aspartate Receptor Antagonist Kynurenic Acid Affects Human Cortical Development. Front Neurosci 2016; 10:435. [PMID: 27746712 PMCID: PMC5043058 DOI: 10.3389/fnins.2016.00435] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/08/2016] [Indexed: 12/25/2022] Open
Abstract
Kynurenic acid (KYNA), a neuroactive metabolite of tryptophan degradation, acts as an endogenous N-methyl-D-aspartate receptor (NMDAR) antagonist. Elevated levels of KYNA have been observed in pregnant women after viral infections and are considered to play a role in neurodevelopmental disorders. However, the consequences of KYNA-induced NMDAR blockade in human cortical development still remain elusive. To study the potential impact of KYNA on human neurodevelopment, we used an in vitro system of multipotent cortical progenitors, i.e., radial glia cells (RGCs), enriched from human cerebral cortex at mid-gestation (16–19 gestational weeks). KYNA treatment significantly decreased RGCs proliferation and survival by antagonizing NMDAR. This alteration resulted in a reduced number of cortical progenitors and neurons while number and activation of astrocytes increased. KYNA treatment reduced differentiation of RGCs into GABAergic neurons, while differentiation into glutamatergic neurons was relatively spared. Furthermore, in mixed cortical cultures KYNA triggered an inflammatory response as evidenced by increased levels of the pro-inflammatory cytokine IL-6. In conclusion, elevated levels of KYNA play a significant role in human RGC fate determination by antagonizing NMDARs and by activating an inflammatory response. The altered cell composition observed in cell culture following exposure to elevated KYNA levels suggests a mechanism for impairment of cortical circuitry formation in the fetal brain after viral infection, as seen in neurodevelopmental disorders such as schizophrenia.
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Affiliation(s)
- Inseyah Bagasrawala
- Department of Neuroscience, University of Connecticut Health Farmington, CT, USA
| | - Nada Zecevic
- Department of Neuroscience, University of Connecticut Health Farmington, CT, USA
| | - Nevena V Radonjić
- Department of Psychiatry, University of Connecticut Health Farmington, CT, USA
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206
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The marmoset: An emerging model to unravel the evolution and development of the primate neocortex. Dev Neurobiol 2016; 77:263-272. [DOI: 10.1002/dneu.22425] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 12/13/2022]
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207
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Sahu G, Malavade K, Jacob T. Cognitive Impairment in Schizophrenia: Interplay of BDNF and Childhood Trauma? A Review of Literature. Psychiatr Q 2016; 87:559-69. [PMID: 26603624 DOI: 10.1007/s11126-015-9409-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cognitive impairment is a core feature of schizophrenia. These deficits can also serve as an endophenotype for the illness in genetic studies. There is evidence that suggests that cognition can be considered a reasonable target for intervention in both schizophrenia and bipolar disorder. One of the most studied genetic phenotypes for psychosis is brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms. BDNF has an established role in neuronal development and cell survival in response to stress and is abnormally expressed in schizophrenia. Studies have shown that childhood trauma is associated with poor prognosis of schizophrenic patients. BDNF-Val66Met polymorphism has been shown to moderate the impact of childhood adversity on later expression of affective symptoms, suggesting the possibility of gene environment interactions. Considering the recent advances of neuroscience an up to date review of relevant literature is warranted in this field. This article reviews the current literature available regarding associations between the Val66Met polymorphism, childhood trauma and cognitive dysfunction in schizophrenia.
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Affiliation(s)
- Geetanjali Sahu
- Department of Psychiatry, Maimonides Medical Center, 4802 Tenth Avenue, Brooklyn, NY, 11219, USA
| | - Kishor Malavade
- Department of Psychiatry, Maimonides Medical Center, 4802 Tenth Avenue, Brooklyn, NY, 11219, USA
- Department of Population Health, Maimonides Medical Center, Brooklyn, NY, USA
| | - Theresa Jacob
- Department of Psychiatry, Maimonides Medical Center, 4802 Tenth Avenue, Brooklyn, NY, 11219, USA.
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208
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David CN, Frias ES, Szu JI, Vieira PA, Hubbard JA, Lovelace J, Michael M, Worth D, McGovern KE, Ethell IM, Stanley BG, Korzus E, Fiacco TA, Binder DK, Wilson EH. GLT-1-Dependent Disruption of CNS Glutamate Homeostasis and Neuronal Function by the Protozoan Parasite Toxoplasma gondii. PLoS Pathog 2016; 12:e1005643. [PMID: 27281462 PMCID: PMC4900626 DOI: 10.1371/journal.ppat.1005643] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 04/28/2016] [Indexed: 01/09/2023] Open
Abstract
The immune privileged nature of the CNS can make it vulnerable to chronic and latent infections. Little is known about the effects of lifelong brain infections, and thus inflammation, on the neurological health of the host. Toxoplasma gondii is a parasite that can infect any mammalian nucleated cell with average worldwide seroprevalence rates of 30%. Infection by Toxoplasma is characterized by the lifelong presence of parasitic cysts within neurons in the brain, requiring a competent immune system to prevent parasite reactivation and encephalitis. In the immunocompetent individual, Toxoplasma infection is largely asymptomatic, however many recent studies suggest a strong correlation with certain neurodegenerative and psychiatric disorders. Here, we demonstrate a significant reduction in the primary astrocytic glutamate transporter, GLT-1, following infection with Toxoplasma. Using microdialysis of the murine frontal cortex over the course of infection, a significant increase in extracellular concentrations of glutamate is observed. Consistent with glutamate dysregulation, analysis of neurons reveal changes in morphology including a reduction in dendritic spines, VGlut1 and NeuN immunoreactivity. Furthermore, behavioral testing and EEG recordings point to significant changes in neuronal output. Finally, these changes in neuronal connectivity are dependent on infection-induced downregulation of GLT-1 as treatment with the ß-lactam antibiotic ceftriaxone, rescues extracellular glutamate concentrations, neuronal pathology and function. Altogether, these data demonstrate that following an infection with T. gondii, the delicate regulation of glutamate by astrocytes is disrupted and accounts for a range of deficits observed in chronic infection. The protozoan parasite Toxoplasma gondii infects a third of the world’s population and causes a chronic lifelong infection in the brain of the host. The consequences of such an infection are poorly understood. Here, we demonstrate that Toxoplasma infection can induce profound changes in astrocyte physiology leading to significant disruption of neuronal networks. Pathology can be rescued by upregulating the astrocytic glutamate transporter, GLT-1, restoring concentrations of extracellular glutamate and EEG power. We suggest that such global dysregulation of neurotransmitters should be considered when determining the effects of infection on the CNS.
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Affiliation(s)
- Clément N. David
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Elma S. Frias
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Jenny I. Szu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Philip A. Vieira
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Jacqueline A. Hubbard
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Jonathan Lovelace
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Marena Michael
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Danielle Worth
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Kathryn E. McGovern
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Iryna M. Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - B. Glenn Stanley
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Edward Korzus
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Todd A. Fiacco
- Department of Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
- * E-mail:
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209
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DNA Damage and Repair in Schizophrenia and Autism: Implications for Cancer Comorbidity and Beyond. Int J Mol Sci 2016; 17:ijms17060856. [PMID: 27258260 PMCID: PMC4926390 DOI: 10.3390/ijms17060856] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/12/2016] [Accepted: 05/27/2016] [Indexed: 12/16/2022] Open
Abstract
Schizophrenia and autism spectrum disorder (ASD) are multi-factorial and multi-symptomatic psychiatric disorders, each affecting 0.5%-1% of the population worldwide. Both are characterized by impairments in cognitive functions, emotions and behaviour, and they undermine basic human processes of perception and judgment. Despite decades of extensive research, the aetiologies of schizophrenia and ASD are still poorly understood and remain a significant challenge to clinicians and scientists alike. Adding to this unsatisfactory situation, patients with schizophrenia or ASD often develop a variety of peripheral and systemic disturbances, one prominent example of which is cancer, which shows a direct (but sometimes inverse) comorbidity in people affected with schizophrenia and ASD. Cancer is a disease characterized by uncontrolled proliferation of cells, the molecular origin of which derives from mutations of a cell's DNA sequence. To counteract such mutations and repair damaged DNA, cells are equipped with intricate DNA repair pathways. Oxidative stress, oxidative DNA damage, and deficient repair of oxidative DNA lesions repair have been proposed to contribute to the development of schizophrenia and ASD. In this article, we summarize the current evidence of cancer comorbidity in these brain disorders and discuss the putative roles of oxidative stress, DNA damage and DNA repair in the aetiopathology of schizophrenia and ASD.
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210
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MiR-130a regulates neurite outgrowth and dendritic spine density by targeting MeCP2. Protein Cell 2016; 7:489-500. [PMID: 27245166 PMCID: PMC4930766 DOI: 10.1007/s13238-016-0272-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 04/13/2016] [Indexed: 01/03/2023] Open
Abstract
MicroRNAs (miRNAs) are critical for both development and function of the central nervous system. Significant evidence suggests that abnormal expression of miRNAs is associated with neurodevelopmental disorders. MeCP2 protein is an epigenetic regulator repressing or activating gene transcription by binding to methylated DNA. Both loss-of-function and gain-of-function mutations in the MECP2 gene lead to neurodevelopmental disorders such as Rett syndrome, autism and MECP2 duplication syndrome. In this study, we demonstrate that miR-130a inhibits neurite outgrowth and reduces dendritic spine density as well as dendritic complexity. Bioinformatics analyses, cell cultures and biochemical experiments indicate that miR-130a targets MECP2 and down-regulates MeCP2 protein expression. Furthermore, expression of the wild-type MeCP2, but not a loss-of-function mutant, rescues the miR-130a-induced phenotype. Our study uncovers the MECP2 gene as a previous unknown target for miR-130a, supporting that miR-130a may play a role in neurodevelopment by regulating MeCP2. Together with data from other groups, our work suggests that a feedback regulatory mechanism involving both miR-130a and MeCP2 may serve to ensure their appropriate expression and function in neural development.
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211
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Green IW, Glausier JR. Different Paths to Core Pathology: The Equifinal Model of the Schizophrenia Syndrome. Schizophr Bull 2016; 42:542-9. [PMID: 26392629 PMCID: PMC4838077 DOI: 10.1093/schbul/sbv136] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Schizophrenia is a clinically heterogeneous disorder that is perhaps more accurately characterized as "the schizophrenia syndrome." This clinical heterogeneity is reflected in the heterogeneous neurobiological presentations associated with the illness. Moreover, even highly specific neural aberrations that are associated with distinct symptoms of schizophrenia are linked to a wide range of risk factors. As such, any individual with schizophrenia likely has a particular set of risk factors that interact and converge to cross the disease threshold, forming a particular etiology that ultimately generates a core pathophysiology. This core pathophysiology may then produce 1 or more symptoms of schizophrenia, leading to common symptoms across individuals in spite of disparate etiologies. As such, the schizophrenia syndrome can be considered as anequifinalentity: a state of dysfunction that can arise from different upstream etiologies. Moreover, schizophrenia etiologies are multifactorial and can involve the interactive effects of a broad range of genetic, environmental, and developmental risk factors. Through a consideration of how disparate etiologies, caused by different sets of risk factors, converge on the same net dysfunction, this paper aims to model the equifinal nature of schizophrenia symptoms. To demonstrate the equifinal model, we discuss how maternal infection and adolescent cannabis use, 2 recognized schizophrenia risk factors, may interact with other genetic, environmental, and/or developmental risk factors to cause the conserved clinical presentation of impaired working memory.
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Affiliation(s)
- Isobel W. Green
- Department of Psychology, Harvard College, Harvard University, Cambridge, MA
| | - Jill R. Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA,*To whom correspondence should be addressed; Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh, Biomedical Science Tower W1654, 3811 O’Hara Street, Pittsburgh, PA 15213, US; tel: 412-624-7869, fax: 412-624-9910, e-mail:
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212
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Ramaekers VT, Sequeira JM, Quadros EV. The basis for folinic acid treatment in neuro-psychiatric disorders. Biochimie 2016; 126:79-90. [PMID: 27068282 DOI: 10.1016/j.biochi.2016.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 04/06/2016] [Indexed: 11/24/2022]
Abstract
Multiple factors such as genetic and extraneous causes (drugs, toxins, adverse psychological events) contribute to neuro-psychiatric conditions. In a subgroup of these disorders, systemic folate deficiency has been associated with macrocytic anemia and neuropsychiatric phenotypes. In some of these, despite normal systemic levels, folate transport to the brain is impaired in the so-called cerebral folate deficiency (CFD) syndromes presenting as developmental and psychiatric disorders. These include infantile-onset CFD syndrome, infantile autism with or without neurologic deficits, a spastic-ataxic syndrome and intractable epilepsy in young children expanding to refractory schizophrenia in adolescents, and finally treatment-resistant major depression in adults. Folate receptor alpha (FRα) autoimmunity with low CSF N(5)-methyl-tetrahydrofolate (MTHF) underlies most CFD syndromes, whereas FRα gene abnormalities and mitochondrial gene defects are rarely found. The age at which FRα antibodies of the blocking type emerge, determines the clinical phenotype. Infantile CFD syndrome and autism with neurological deficits tend to be characterized by elevated FRα antibody titers and low CSF MTHF. In contrast, in infantile autism and intractable schizophrenia, abnormal behavioral signs and symptoms may wax and wane with fluctuating FRα antibody titers over time accompanied by cycling changes in CSF folate, tetrahydrobiopterin (BH4) and neurotransmitter metabolites ranging between low and normal levels. We propose a hypothetical model explaining the pathogenesis of schizophrenia. Based on findings from clinical, genetic, spinal fluid and MRI spectroscopic studies, we discuss the neurochemical changes associated with these disorders, metabolic and regulatory pathways, synthesis and catabolism of neurotransmitters, and the impact of oxidative stress on the pathogenesis of these conditions. A diagnostic algorithm and therapeutic regimens using high dose folinic acid, corticosteroids and milk-free diet is presented which has proven to be beneficial in providing adequate folate to the brain and decreasing the FRα autoantibody titer in those positive for the antibody.
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Affiliation(s)
- V T Ramaekers
- Division of Child Neurology and Center of Autism, Centre Hospitalier Universitaire Liège, Belgium.
| | - J M Sequeira
- Department of Medicine, Downstate Medical Center, State University New York, USA
| | - E V Quadros
- Department of Medicine, Downstate Medical Center, State University New York, USA
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213
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Hoppenrath K, Härtig W, Funke K. Intermittent Theta-Burst Transcranial Magnetic Stimulation Alters Electrical Properties of Fast-Spiking Neocortical Interneurons in an Age-Dependent Fashion. Front Neural Circuits 2016; 10:22. [PMID: 27065812 PMCID: PMC4811908 DOI: 10.3389/fncir.2016.00022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/13/2016] [Indexed: 11/13/2022] Open
Abstract
Modulation of human cortical excitability by repetitive transcranial magnetic stimulation (rTMS) appears to be in part related to changed activity of inhibitory systems. Our own studies showed that intermittent theta-burst stimulation (iTBS) applied via rTMS to rat cortex primarily affects the parvalbumin-expressing (PV) fast-spiking interneurons (FSIs), evident via a strongly reduced PV expression. We further found the iTBS effect on PV to be age-dependent since no reduction in PV could be induced before the perineuronal nets (PNNs) of FSIs start to grow around postnatal day (PD) 30. To elucidate possible iTBS-induced changes in the electrical properties of FSIs and cortical network activity during cortical critical period, we performed ex vivo-in vitro whole-cell patch clamp recordings from pre-labeled FSIs in the current study. FSIs of verum iTBS-treated rats displayed a higher excitability than sham-treated controls at PD29-38, evident as higher rates of induced action potential firing at low current injections (100-200 pA) and a more depolarized resting membrane potential. This effect was absent in younger (PD26-28) and older animals (PD40-62). Slices of verum iTBS-treated rats further showed higher rates of spontaneous excitatory postsynaptic currents (sEPSCs). Based on these and previous findings we conclude that FSIs are particularly sensitive to TBS during early cortical development, when FSIs show an activity-driven step of maturation which is paralleled by intense growth of the PNNs and subsequent closure of the cortical critical period. Although to be proven further, rTMS may be a possible early intervention to compensate for hypo-activity related mal-development of cortical neuronal circuits.
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Affiliation(s)
- Kathrin Hoppenrath
- Department of Neurophysiology, Medical Faculty, Ruhr-University BochumBochum, Germany; Rottendorf Pharma GmbHEnnigerloh, Germany
| | - Wolfgang Härtig
- Pathophysiology of Neuroglia, Paul Flechsig Institute for Brain Research, University of Leipzig Leipzig, Germany
| | - Klaus Funke
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum Bochum, Germany
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Demeter K, Török B, Fodor A, Varga J, Ferenczi S, Kovács KJ, Eszik I, Szegedi V, Zelena D. Possible contribution of epigenetic changes in the development of schizophrenia-like behavior in vasopressin-deficient Brattleboro rats. Behav Brain Res 2016; 300:123-34. [DOI: 10.1016/j.bbr.2015.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/04/2015] [Accepted: 12/09/2015] [Indexed: 12/25/2022]
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215
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Roffman JL. Introduction. Harv Rev Psychiatry 2016; 24:77-9. [PMID: 26954592 DOI: 10.1097/hrp.0000000000000116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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216
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Lipopolysaccharide exposure during late embryogenesis results in diminished locomotor activity and amphetamine response in females and spatial cognition impairment in males in adult, but not adolescent rat offspring. Behav Brain Res 2016; 299:72-80. [DOI: 10.1016/j.bbr.2015.11.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/17/2015] [Accepted: 11/20/2015] [Indexed: 01/15/2023]
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217
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Li Y, Xie S, Liu B, Song M, Chen Y, Li P, Lu L, Lv L, Wang H, Yan H, Yan J, Zhang H, Zhang D, Jiang T. Diffusion magnetic resonance imaging study of schizophrenia in the context of abnormal neurodevelopment using multiple site data in a Chinese Han population. Transl Psychiatry 2016; 6:e715. [PMID: 26784969 PMCID: PMC5068876 DOI: 10.1038/tp.2015.202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 11/05/2015] [Indexed: 12/19/2022] Open
Abstract
Schizophrenia has increasingly been considered a neurodevelopmental disorder, and the advancement of neuroimaging techniques and associated computational methods has enabled quantitative re-examination of this important theory on the pathogenesis of the disease. Inspired by previous findings from neonatal brains, we proposed that an increase in diffusion magnetic resonance imaging (dMRI) mean diffusivity (MD) should be observed in the cerebral cortex of schizophrenia patients compared with healthy controls, corresponding to lower tissue complexity and potentially a failure to reach cortical maturation. We tested this hypothesis using dMRI data from a Chinese Han population comprising patients from four different hospital sites. Utilizing data-driven methods based on the state-of-the-art tensor-based registration algorithm, significantly increased MD measurements were consistently observed in the cortex of schizophrenia patients across all four sites, despite differences in psychopathology, exposure to antipsychotic medication and scanners used for image acquisition. Specifically, we found increased MD in the limbic system of the schizophrenic brain, mainly involving the bilateral insular and prefrontal cortices. In light of the existing literature, we speculate that this may represent a neuroanatomical signature of the disorder, reflecting microstructural deficits due to developmental abnormalities. Our findings not only provide strong support to the abnormal neurodevelopment theory of schizophrenia, but also highlight an important neuroimaging endophenotype for monitoring the developmental trajectory of high-risk subjects of the disease, thereby facilitating early detection and prevention.
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Affiliation(s)
- Y Li
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - S Xie
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - B Liu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - M Song
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Y Chen
- Department of Psychiatry, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - P Li
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - L Lu
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - L Lv
- Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
- Henan Key Lab of Biological Psychiatry, Xinxiang Medical University, Xinxiang, China
| | - H Wang
- Department of Psychiatry, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - H Yan
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - J Yan
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
| | - H Zhang
- Department of Psychiatry, Henan Mental Hospital, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
- Department of Psychology, Xinxiang Medical University, Xinxiang, China
| | - D Zhang
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
- Center for Life Sciences/PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - T Jiang
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China
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218
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Disease signatures for schizophrenia and bipolar disorder using patient-derived induced pluripotent stem cells. Mol Cell Neurosci 2016; 73:96-103. [PMID: 26777134 DOI: 10.1016/j.mcn.2016.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/05/2016] [Accepted: 01/11/2016] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia and bipolar disorder are complex psychiatric disorders that present unique challenges in the study of disease biology. There are no objective biological phenotypes for these disorders, which are characterized by complex genetics and prominent roles for gene-environment interactions. The study of the neurobiology underlying these severe psychiatric disorders has been hindered by the lack of access to the tissue of interest - neurons from patients. The advent of reprogramming methods that enable generation of induced pluripotent stem cells (iPSCs) from patient fibroblasts and peripheral blood mononuclear cells has opened possibilities for new approaches to study relevant disease biology using iPSC-derived neurons. While early studies with patient iPSCs have led to promising and intriguing leads, significant hurdles remain in our attempts to capture the complexity of these disorders in vitro. We present here an overview of studies to date of schizophrenia and bipolar disorder using iPSC-derived neuronal cells and discuss potential future directions that can result in the identification of robust and valid cellular phenotypes that in turn can lay the groundwork for meaningful clinical advances.
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