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Archer T, Beninger RJ, Palomo T, Kostrzewa RM. Epigenetics and biomarkers in the staging of neuropsychiatric disorders. Neurotox Res 2010; 18:347-66. [PMID: 20237880 DOI: 10.1007/s12640-010-9163-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 01/29/2010] [Accepted: 02/18/2010] [Indexed: 01/05/2023]
Abstract
Epigenetics, or alterations in the phenotype or gene expression due to mechanisms other than changes in the underlying DNA sequence, reflects the sensitivity and responsiveness of human and animal brains in constantly varying circumstances regulating gene expression profiles that define the biomarkers and present the ultimate phenotypical outcomes, such as cognition and emotion. Epigenetics is associated with functionally relevant alterations to the genome in such a fashion that under the particular conditions of early, adolescent, and adult life, environmental signals may activate intracellular pathways that remodel the "epigenome," triggering changes in gene expression and neural function. Thus, genetic influences in neuropsychiatric disorders that are subject to clinical staging, epigenetics in schizophrenia, epigenetic considerations in the expression of sensorimotor gating resulting from disease conditions, biomarkers of drug use and addiction, current notions on the role of dopamine in schizophrenia spectrum disorders, and the discrete interactions of biomarkers in persistent memory were to greater or lesser extents reflected upon. The relative contributions of endophenotypes and epistasis for mediating epigenetic phenomena and the outcomes as observed in the analysis of biomarkers appear to offer a multitude of interactive combinations to further complicate the labyrinthine machinations of diagnosis, intervention, and prognosis.
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Affiliation(s)
- Trevor Archer
- Department of Psychology, University of Gothenburg, Box 500, 405 30, Gothenburg, Sweden.
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Isayama RN, Leite PEC, Lima JPM, Uziel D, Yamasaki EN. Impact of ethanol on the developing GABAergic system. Anat Rec (Hoboken) 2010; 292:1922-39. [PMID: 19943346 DOI: 10.1002/ar.20966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alcohol intake during pregnancy has a tremendous impact on the developing brain. Embryonic and early postnatal alcohol exposures have been investigated experimentally to elucidate the fetal alcohol spectrum disorders' (FASD) milieu, and new data have emerged to support a devastating effect on the GABAergic system in the adult and developing nervous system. GABA is a predominantly inhibitory neurotransmitter that during development excites neurons and orchestrates several developmental processes such as proliferation, migration, differentiation, and synaptogenesis. This review summarizes and brings new data on neurodevelopmental aspects of the GABAergic system with FASD in experimental telencephalic models.
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Affiliation(s)
- Ricardo Noboro Isayama
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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53
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Guan H, Maness PF. Perisomatic GABAergic innervation in prefrontal cortex is regulated by ankyrin interaction with the L1 cell adhesion molecule. Cereb Cortex 2010; 20:2684-93. [PMID: 20156840 DOI: 10.1093/cercor/bhq016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The L1 adhesion molecule functions in axon growth and guidance, but a role in synaptic development of cortical inhibitory interneurons is largely unexplored. L1 mediates adhesion by engaging the actin cytoskeleton through binding the actin/spectrin adapter protein ankyrin. Loss of L1-ankyrin interaction impaired process elaboration/branching by GABAergic interneurons, including basket cells, and reduced the number of perisomatic synapses in the cingulate cortex as shown in L1 mutant mice (L1YH) with a mutation in the ankyrin-binding site, either alone or intercrossed with GAD67-enhanced green fluorescence protein reporter mice. Electron microscopy revealed that perisomatic inhibitory synapses but not excitatory synapses in the neuropil were specifically affected. In wild-type cingulate cortex, L1 colocalized with perisomatic synaptic markers, whereas L1 phosphorylation on Tyr(1229) decreased postnatally, correlating with increased ankyrin binding and synaptic development. These results suggest a novel role for L1 engagement with the actin cytoskeleton in development of inhibitory connectivity within the cingulate cortex.
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Affiliation(s)
- Hanjun Guan
- Department of Biochemistry, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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Castillo MA, Ghose S, Tamminga CA, Ulery-Reynolds PG. Deficits in syntaxin 1 phosphorylation in schizophrenia prefrontal cortex. Biol Psychiatry 2010; 67:208-16. [PMID: 19748077 DOI: 10.1016/j.biopsych.2009.07.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Schizophrenia has been described as a disease of the synapse. On the basis of previous studies reporting reductions in the levels and activity of CK2 (also know as casein kinase 2 or II) in the brain of subjects with schizophrenia, we hypothesized that CK2-mediated phosphorylation of the presynaptic protein syntaxin 1 (Stx 1) is deficient in schizophrenia. This in turn could affect the binding of Stx 1 to its protein partners and result in abnormal neurotransmitter release and synaptic transmission. METHODS We analyzed post mortem prefrontal cortex samples from 15 schizophrenia cases and matched controls by quantitative immunoblotting. RESULTS In addition to replicating previous findings of reduced CK2 levels, we show that as predicted, the deficit in CK2 correlates with a deficit in phospho-Stx 1. In contrast, we find that these deficits are not present in depression cases. Further, we show that the reduced levels of CK2 and phospho-Stx 1 are not due to treatment with antipsychotic drugs (APDs). In fact, APDs seem to increase both CK2 and phospho-Stx 1, suggesting that their therapeutic action may be associated with the reversal of these deficits. Finally, we show that lower phospho-Stx 1 levels are associated with reduced binding of Stx 1 to SNAP-25 and MUNC18 and decreased SNARE complex formation. CONCLUSIONS Our findings constitute the first report of altered phosphorylation of a key component for neurotransmitter release in humans and suggest that regulation of Stx 1 by CK2-mediated phosphorylation could play a role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Max A Castillo
- Department of Neurology, The University of Texas, Southwestern Medical Center, Dallas, Texas, USA
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Perez-Costas E, Melendez-Ferro M, Roberts RC. Basal ganglia pathology in schizophrenia: dopamine connections and anomalies. J Neurochem 2010; 113:287-302. [PMID: 20089137 DOI: 10.1111/j.1471-4159.2010.06604.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Schizophrenia is a severe mental illness that affects 1% of the world population. The disease usually manifests itself in early adulthood with hallucinations, delusions, cognitive and emotional disturbances and disorganized thought and behavior. Dopamine was the first neurotransmitter to be implicated in the disease, and though no longer the only suspect in schizophrenia pathophysiology, it obviously plays an important role. The basal ganglia are the site of most of the dopamine neurons in the brain and the target of anti-psychotic drugs. In this review, we will start with an overview of basal ganglia anatomy emphasizing dopamine circuitry. Then, we will review the major deficits in dopamine function in schizophrenia, emphasizing the role of excessive dopamine in the basal ganglia and the link to psychosis.
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Affiliation(s)
- Emma Perez-Costas
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Simpson SM, Menard JL, Reynolds JN, Beninger RJ. Post-weaning social isolation increases activity in a novel environment but decreases defensive burying and subchronic MK-801 enhances the activity but not the burying effect in rats. Pharmacol Biochem Behav 2009; 95:72-9. [PMID: 20035782 DOI: 10.1016/j.pbb.2009.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 12/01/2009] [Accepted: 12/07/2009] [Indexed: 10/20/2022]
Abstract
Subchronic treatment with a non-competitive glutamate NMDA-receptor antagonist [e.g., MK-801 or phencyclidine] or social isolation (SI) from weaning (age 21 days) to adulthood (age 56 days) produce deficits similar to some of the positive and negative symptoms of schizophrenia. Few studies have evaluated the effects of these treatments on emotional behavior. We hypothesized that subchronic MK-801, post-weaning SI or the two in combination would alter activity in a novel environment, anxiety-like behaviors in the elevated plus-maze, coping responses in the defensive burying paradigm and social behavior. In experiment 1, SI rats (n=17) showed increased locomotor activity when exposed to a novel environment, no change in plus-maze behavior and decreased defensive burying when compared to group housed rats (n=16). Subchronic MK-801 enhanced the increase in activity but not the decrease in burying in SI rats. Experiment 2 evaluated the effects on social behavior of post-weaning SI. The locomotor and burying results of experiment 1 were replicated and SI rats (n=9) were found to decrease orientation towards a novel conspecific social target when compared to group housed rats (n=8). The behavioral abnormalities of SI rats may be a manifestation of GABAergic dysfunction that has recently become evident in schizophrenia.
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Affiliation(s)
- Sarah M Simpson
- Department of Psychology, Queen's University, Kingston, Ontario, Canada
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Affiliation(s)
- Sanghyeon Kim
- Stanley Brain Research Laboratory, Stanley Medical Research Institute, 9800 Medical Center Drive, Rockville, MD 20850,To whom correspondence should be addressed; tel: 240-499-1186, fax: 301-251-8602, e-mail:
| | - Maree J. Webster
- Stanley Brain Research Laboratory, Stanley Medical Research Institute, 9800 Medical Center Drive, Rockville, MD 20850
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Zhang XM, Cai Y, Chu Y, Chen EY, Feng JC, Luo XG, Xiong K, Struble RG, Clough RW, Patrylo PR, Kordower JH, Yan XX. Doublecortin-expressing cells persist in the associative cerebral cortex and amygdala in aged nonhuman primates. Front Neuroanat 2009; 3:17. [PMID: 19862344 PMCID: PMC2766270 DOI: 10.3389/neuro.05.017.2009] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 08/21/2009] [Indexed: 11/18/2022] Open
Abstract
A novel population of cells that express typical immature neuronal markers including doublecortin (DCX+) has been recently identified throughout the adult cerebral cortex of relatively large mammals (guinea pig, rabbit, cat, monkey and human). These cells are more common in the associative relative to primary cortical areas and appear to develop into interneurons including type II nitrinergic neurons. Here we further describe these cells in the cerebral cortex and amygdala, in comparison with DCX+ cells in the hippocampal dentate gyrus, in three age groups of rhesus monkeys: young adult (12.3 ± 0.2 years, n = 3), mid-age (21.2 ± 1.9 years, n = 3) and aged (31.3 ± 1.8 years, n = 4). DCX+ cells with a heterogeneous morphology persisted in layers II/III primarily over the associative cortex and amygdala in all groups (including in two old animals with cerebral amyloid pathology), showing a parallel decline in cell density with age across regions. In contrast to the cortex and amygdala, DCX+ cells in the subgranular zone diminished in the mid-age and aged groups. DCX+ cortical cells might arrange as long tangential migratory chains in the mid-age and aged animals, with apparently distorted cell clusters seen in the aged group. Cortical DCX+ cells colocalized commonly with polysialylated neural cell adhesion molecule and partially with neuron-specific nuclear protein and γ-aminobutyric acid, suggesting a potential differentiation of these cells into interneuron phenotype. These data suggest a life-long role for immature interneuron-like cells in the associative cerebral cortex and amygdala in nonhuman primates.
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Affiliation(s)
- Xue-Mei Zhang
- Department of Anatomy, Southern Illinois University School of Medicine Carbondale, IL, USA
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Somatostatin, Alzheimer's disease and cognition: An old story coming of age? Prog Neurobiol 2009; 89:153-61. [DOI: 10.1016/j.pneurobio.2009.07.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/27/2009] [Accepted: 07/02/2009] [Indexed: 12/21/2022]
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Bodarky CL, Halene TB, Ehrlichman RS, Banerjee A, Ray R, Hahn CG, Jonak G, Siegel SJ. Novel environment and GABA agonists alter event-related potentials in N-methyl-D-aspartate NR1 hypomorphic and wild-type mice. J Pharmacol Exp Ther 2009; 331:308-18. [PMID: 19602553 DOI: 10.1124/jpet.109.150938] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Clinical and experimental data suggest dysregulation of N-methyl-d-aspartate receptor (NMDAR)-mediated glutamatergic pathways in schizophrenia. The interaction between NMDAR-mediated abnormalities and the response to novel environment has not been studied. Mice expressing 5 to 10% of normal N-methyl-d-aspartate receptor subunit 1 (NR1) subunits [NR1(neo)(-/-)] were compared with wild-type littermates for positive deflection at 20 ms (P20) and negative deflection at 40 ms (N40) auditory event-related potentials (ERPs). Groups were tested for habituation within and across five testing sessions, with novel environment tested during a sixth session. Subsequently, we examined the effects of a GABA(A) positive allosteric modulator (chlordiazepoxide) and a GABA(B) receptor agonist (baclofen) as potential interventions to normalize aberrant responses. There was a reduction in P20, but not N40 amplitude within each habituation day. Although there was no amplitude or gating change across habituation days, there was a reduction in P20 and N40 amplitude and gating in the novel environment. There was no difference between genotypes for N40. Only NR1(neo)(-/-) mice had reduced P20 in the novel environment. Chlordiazepoxide increased N40 amplitude in wild-type mice, whereas baclofen increased P20 amplitude in NR1(neo)(-/-) mice. As noted in previous publications, the pattern of ERPs in NR1(neo)(-/-) mice does not recapitulate abnormalities in schizophrenia. In addition, reduced NR1 expression does not influence N40 habituation but does affect P20 in a novel environment. Thus, the pattern of P50 (positive deflection at 50 ms) but not N100 (negative deflection at 100 ms) in human studies may relate to subjects' reactions to unfamiliar environments. In addition, NR1 reduction decreased GABA(A) receptor-mediated effects on ERPs while causing increased GABA(B) receptor-mediated effects. Future studies will examine changes in GABA receptor subunits after reductions in NR1 expression.
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Lakhan SE, Vieira KF. Schizophrenia pathophysiology: are we any closer to a complete model? Ann Gen Psychiatry 2009; 8:12. [PMID: 19445674 PMCID: PMC2689221 DOI: 10.1186/1744-859x-8-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 05/15/2009] [Indexed: 01/13/2023] Open
Abstract
Schizophrenia, a severe brain disorder that involves hallucinations, disordered thinking and deficiencies in cognition, has been studied for decades in order to determine the early events that lead to this neurological disorder. In this review, we interpret the developmental and genetic models that have been proposed and treatment options associated with these models. Schizophrenia was initially thought to be hereditary based on studies of high incidence in certain families. Additionally, studies on specific genes such as ZDHHC8 and DTNBP1 seem to suggest susceptibility to the onset of this disorder. However, no single gene variation has been linked to schizophrenia, and recent evidence on sporadic cases of schizophrenia refutes genetics as being a singular cause of the disease. In addition, current data suggests neurodevelopmental or environmental causes such as viral infections and prenatal/perinatal complications. Before any brain disorder can be understood, however, multiple cognitive neuroscientific models that accommodate evidence from many biomedical research fields should be considered, and unfortunately, many of these models are in the earliest stages of development. Consequently, it makes us question whether we are any closer to an adequate understanding of the pathophysiology of schizophrenia.
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Affiliation(s)
- Shaheen E Lakhan
- Global Neuroscience Initiative Foundation, Los Angeles, California, USA.
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Archer T, Kostrzewa RM, Beninger RJ, Palomo T. Cognitive symptoms facilitatory for diagnoses in neuropsychiatric disorders: Executive functions and locus of control. Neurotox Res 2008; 14:205-25. [DOI: 10.1007/bf03033811] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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