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Maiti R, Mishra BR, Jena M, Mishra A, Nath S. Effect of Haloperidol and Risperidone on Serum Melatonin and GAP-43 in Patients with Schizophrenia: A Prospective Cohort Study. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE : THE OFFICIAL SCIENTIFIC JOURNAL OF THE KOREAN COLLEGE OF NEUROPSYCHOPHARMACOLOGY 2021; 19:125-134. [PMID: 33508796 PMCID: PMC7851459 DOI: 10.9758/cpn.2021.19.1.125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/06/2020] [Accepted: 09/07/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Serum melatonin, a biomarker of circadian rhythm, can upregulate Growth-associated protein 43 (GAP-43) which is involved in neural regeneration and plasticity. The present study was conducted to investigate the adequacy of the first-line antipsychotic drugs to improve sleep and circadian rhythm disruptions by assessing the effect of haloperidol and risperidone on serum melatonin and GAP-43 in schizophrenia. METHODS In this cohort study, 100 schizophrenic patients were recruited, and clinical evaluations were done using the Positive and Negative Syndrome Scale (PANSS) and the Pittsburgh sleep quality index (PSQI). The patients with predominantly positive symptoms taking haloperidol (Group I) and patients with predominantly negative symptoms taking risperidone (Group II) were admitted and serum melatonin, arylalkylamine N-acetyltransferase, GAP-43 and urinary melatonin were estimated. After 8 weeks, all clinical and biochemical parameters were repeated. RESULTS Serum melatonin (2:00 hours) was significantly decreased in both haloperidol (2.42; 95% confidence interval [95% CI]: 0.67-4.17; p = 0.008) and risperidone group (3.40; 95% CI: 0.54-6.25; p = 0.021). Urinary melatonin was significantly decreased in both haloperidol (p = 0.005) and risperidone group (p = 0.014). PSQI score was significantly increased in both haloperidol (p = 0.001) and risperidone group (p = 0.003). Serum GAP-43 was significantly decreased in both haloperidol and risperidone group (p < 0.001). PANSS decreased significantly in both the groups and there was a significant negative correlation between serum melatonin at 2:00 hours and PANSS (r = -0.5) at baseline. CONCLUSION Monotherapy with haloperidol and risperidone can achieve symptomatic improvement but cannot improve sleep and circadian rhythm disturbances in schizophrenia.
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Affiliation(s)
- Rituparna Maiti
- Departments of Pharmacology, All India Institute of Medical Sciences (AIIMS), Odisha, India
| | - Biswa Ranjan Mishra
- Departments of Psychiatry, All India Institute of Medical Sciences (AIIMS), Odisha, India
| | - Monalisa Jena
- Departments of Pharmacology, All India Institute of Medical Sciences (AIIMS), Odisha, India
| | - Archana Mishra
- Department of Pharmacology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Santanu Nath
- Departments of Psychiatry, All India Institute of Medical Sciences (AIIMS), Odisha, India
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Crosstalk between endoplasmic reticulum stress and oxidative stress in schizophrenia: The dawn of new therapeutic approaches. Neurosci Biobehav Rev 2017; 83:589-603. [DOI: 10.1016/j.neubiorev.2017.08.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/09/2017] [Accepted: 08/30/2017] [Indexed: 01/15/2023]
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Fluvoxamine alleviates seizure activity and downregulates hippocampal GAP-43 expression in pentylenetetrazole-kindled mice. Behav Pharmacol 2015; 26:369-82. [DOI: 10.1097/fbp.0000000000000127] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Han MH, Jiao S, Jia JM, Chen Y, Chen CY, Gucek M, Markey SP, Li Z. The novel caspase-3 substrate Gap43 is involved in AMPA receptor endocytosis and long-term depression. Mol Cell Proteomics 2013; 12:3719-31. [PMID: 24023391 DOI: 10.1074/mcp.m113.030676] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The cysteine protease caspase-3, best known as an executioner of cell death in apoptosis, also plays a non-apoptotic role in N-methyl-d-aspartate receptor-dependent long-term depression of synaptic transmission (NMDAR-LTD) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor endocytosis in neurons. The mechanism by which caspase-3 regulates LTD and AMPA receptor endocytosis, however, remains unclear. Here, we addressed this question by using an enzymatic N-terminal peptide enrichment method and mass spectrometry to identify caspase-3 substrates in neurons. Of the many candidates revealed by this proteomic study, we have confirmed BASP1, Dbn1, and Gap43 as true caspase-3 substrates. Moreover, in hippocampal neurons, Gap43 mutants deficient in caspase-3 cleavage inhibit AMPA receptor endocytosis and LTD. We further demonstrated that Gap43, a protein well-known for its functions in axons, is also localized at postsynaptic sites. Our study has identified Gap43 as a key caspase-3 substrate involved in LTD and AMPA receptor endocytosis, uncovered a novel postsynaptic function for Gap43 and provided new insights into how long-term synaptic depression is induced.
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Affiliation(s)
- Meng-Hsuan Han
- National Institute of Mental Health, Bethesda, Maryland 20892
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5
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Jenkins TA. Perinatal complications and schizophrenia: involvement of the immune system. Front Neurosci 2013; 7:110. [PMID: 23805069 PMCID: PMC3691516 DOI: 10.3389/fnins.2013.00110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 06/01/2013] [Indexed: 11/13/2022] Open
Abstract
The neurodevelopmental hypothesis of schizophrenia suggests that, at least in part, events occurring within the intrauterine or perinatal environment at critical times of brain development underlies emergence of the psychosis observed during adulthood, and brain pathologies that are hypothesized to be from birth. All potential risks stimulate activation of the immune system, and are suggested to act in parallel with an underlying genetic liability, such that an imperfect regulation of the genome mediates these prenatal or early postnatal environmental effects. Epidemiologically based animal models looking at environment and with genes have provided us with a wealth of knowledge in the understanding of the pathophysiology of schizophrenia, and give us the best possibility for interventions and treatments for schizophrenia.
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Affiliation(s)
- Trisha A Jenkins
- School of Medical Sciences, Health Innovations Research Institute, RMIT University Bundoora, VIC, Australia
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Lipska BK. Neonatal disconnection of the rat hippocampus: a neurodevelopmental model of schizophrenia. DIALOGUES IN CLINICAL NEUROSCIENCE 2012. [PMID: 22034469 PMCID: PMC3181704 DOI: 10.31887/dcns.2002.4.4/blipska] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In the context of our current knowledge about schizophrenia, heuristic models of psychiatric disorders may be used to test the plausibility of theories developed on the basis of new emerging biological findings, explore mechanisms of schizophrenia-like phenomena, and develop potential new treatments. In a series of studies, we have shown that neonatal excitotoxic lesions of the rat ventral hippocampus (VH) may serve as a heuristic model. The model appears to mimic a spectrum of neurobiological and behavioral features of schizophrenia, including functional pathology in presumably critical brain regions interconnected with the hippocampal formation and targeted by antipsychotic drugs (the striatum/nucleus accumbens and the prefrontal cortex), and leads in adolescence or early adulthood to the emergence of abnormalities in a number of dopamine-related behaviors. Moreover, our data show that even transient inactivation of the VH during a critical period of development, which produces subtle, if any, anatomical changes in the hippocampus, may be sufficient to disrupt normal maturation of the prefrontal cortex (and perhaps, other interconnected latematuring regions) and trigger behavioral changes similar to those observed in animals with the permanent excitotoxic lesion. These results represent a potential new model of aspects of schizophrenia without a gross anatomical lesion.
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Affiliation(s)
- Barbara K Lipska
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, NIH, IRP, Bethescla, Md, USA
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7
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Shen YC, Chen CH. Schizophrenia as a neuronal synaptic disorder related to multiple rare genetic mutations. Tzu Chi Med J 2012. [DOI: 10.1016/j.tcmj.2012.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Reduced myelin basic protein and actin-related gene expression in visual cortex in schizophrenia. PLoS One 2012; 7:e38211. [PMID: 22675524 PMCID: PMC3365879 DOI: 10.1371/journal.pone.0038211] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 05/03/2012] [Indexed: 12/15/2022] Open
Abstract
Most brain gene expression studies of schizophrenia have been conducted in the frontal cortex or hippocampus. The extent to which alterations occur in other cortical regions is not well established. We investigated primary visual cortex (Brodmann area 17) from the Stanley Neuropathology Consortium collection of tissue from 60 subjects with schizophrenia, bipolar disorder, major depression, or controls. We first carried out a preliminary array screen of pooled RNA, and then used RT-PCR to quantify five mRNAs which the array identified as differentially expressed in schizophrenia (myelin basic protein [MBP], myelin-oligodendrocyte glycoprotein [MOG], β-actin [ACTB], thymosin β-10 [TB10], and superior cervical ganglion-10 [SCG10]). Reduced mRNA levels were confirmed by RT-PCR for MBP, ACTB and TB10. The MBP reduction was limited to transcripts containing exon 2. ACTB and TB10 mRNAs were also decreased in bipolar disorder. None of the transcripts were altered in subjects with major depression. Reduced MBP mRNA in schizophrenia replicates findings in other brain regions and is consistent with oligodendrocyte involvement in the disorder. The decreases in expression of ACTB, and the actin-binding protein gene TB10, suggest changes in cytoskeletal organisation. The findings confirm that the primary visual cortex shows molecular alterations in schizophrenia and extend the evidence for a widespread, rather than focal, cortical pathophysiology.
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Shen YC, Tsai HM, Cheng MC, Hsu SH, Chen SF, Chen CH. Genetic and functional analysis of the gene encoding GAP-43 in schizophrenia. Schizophr Res 2012; 134:239-45. [PMID: 22138049 DOI: 10.1016/j.schres.2011.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 10/29/2011] [Accepted: 11/13/2011] [Indexed: 10/14/2022]
Abstract
OBJECTIVES In earlier reports, growth-associated protein 43 (GAP-43) has been shown to be critical for initial establishment or reorganization of synaptic connections, a process thought to be disrupted in schizophrenia. Additionally, abnormal GAP-43 expression in different brain regions has been linked to this disorder in postmortem brain studies. In this study, we investigated the involvement of the gene encoding GAP-43 in the susceptibility to schizophrenia. METHODS We searched for genetic variants in the promoter region and 3 exons (including both UTR ends) of the GAP-43 gene using direct sequencing in a sample of patients with schizophrenia (n=586) and non-psychotic controls (n=576), both being Han Chinese from Taiwan, and conducted an association and functional study. RESULTS We identified 11 common polymorphisms in the GAP-43 gene. SNP and haplotype-based analyses displayed no associations with schizophrenia. Additionally, we identified 4 rare variants in 5 out of 586 patients, including 1 variant located at the promoter region (c.-258-4722G>T) and 1 synonymous (V110V) and 2 missense (G150R and P188L) variants located at exon 2. No rare variants were found in the control subjects. The results of the reporter gene assay demonstrated that the regulatory activity of construct containing c.-258-4722T was significantly lower as compared to the wild type construct (c.-258-4722G; p<0.001). In silico analysis also demonstrated the functional relevance of other rare variants. CONCLUSIONS Our study lends support to the hypothesis of multiple rare mutations in schizophrenia, and it provides genetic clues that indicate the involvement of GAP-43 in this disorder.
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Affiliation(s)
- Yu-Chih Shen
- Department of Psychiatry, Tzu Chi General Hospital, Hualien, Taiwan.
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Hradetzky E, Sanderson TM, Tsang TM, Sherwood JL, Fitzjohn SM, Lakics V, Malik N, Schoeffmann S, O'Neill MJ, Cheng TMK, Harris LW, Rahmoune H, Guest PC, Sher E, Collingridge GL, Holmes E, Tricklebank MD, Bahn S. The methylazoxymethanol acetate (MAM-E17) rat model: molecular and functional effects in the hippocampus. Neuropsychopharmacology 2012; 37:364-77. [PMID: 21956444 PMCID: PMC3242314 DOI: 10.1038/npp.2011.219] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Administration of the DNA-alkylating agent methylazoxymethanol acetate (MAM) on embryonic day 17 (E17) produces behavioral and anatomical brain abnormalities, which model some aspects of schizophrenia. This has lead to the premise that MAM rats are a neurodevelopmental model for schizophrenia. However, the underlying molecular pathways affected in this model have not been elucidated. In this study, we investigated the molecular phenotype of adult MAM rats by focusing on the frontal cortex and hippocampal areas, as these are known to be affected in schizophrenia. Proteomic and metabonomic analyses showed that the MAM treatment on E17 resulted primarily in deficits in hippocampal glutamatergic neurotransmission, as seen in some schizophrenia patients. Most importantly, these results were consistent with our finding of functional deficits in glutamatergic neurotransmission, as identified using electrophysiological recordings. Thus, this study provides the first molecular evidence, combined with functional validation, that the MAM-E17 rat model reproduces hippocampal deficits relevant to the pathology of schizophrenia.
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Affiliation(s)
- Eva Hradetzky
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK,Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Thomas M Sanderson
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Tsz M Tsang
- Faculty of Medicine, Division of Surgery, Oncology, Reproductive Biology and Anesthetics, Department of Biomolecular Medicine, Imperial College, London, UK
| | - John L Sherwood
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Stephen M Fitzjohn
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Viktor Lakics
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Nadia Malik
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Stephanie Schoeffmann
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Michael J O'Neill
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Tammy MK Cheng
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Laura W Harris
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Hassan Rahmoune
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Paul C Guest
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Emanuele Sher
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK
| | - Graham L Collingridge
- MRC Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, Bristol, UK
| | - Elaine Holmes
- Faculty of Medicine, Division of Surgery, Oncology, Reproductive Biology and Anesthetics, Department of Biomolecular Medicine, Imperial College, London, UK
| | - Mark D Tricklebank
- Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Windlesham, Surrey, UK,Lilly Centre for Cognitive Neuroscience, Eli Lilly & Co. Ltd, Erl Wood Manor, Windlesham, Surrey, UK, Tel: +44 (0) 1276-483000, Fax: +44 (0) 1276-484921, E-mail:
| | - Sabine Bahn
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK,Department of Neuroscience, Erasmus University Medical Centre, Rotterdam, The Netherlands,Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, Cambridgeshire CB2 1QT, UK, Tel: +44 (0)1223 334151, Fax: +44 (0)1223 334162, E-mail:
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11
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Bennett M. Schizophrenia: susceptibility genes, dendritic-spine pathology and gray matter loss. Prog Neurobiol 2011; 95:275-300. [DOI: 10.1016/j.pneurobio.2011.08.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 02/01/2023]
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12
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Fung SJ, Sivagnanasundaram S, Shannon Weickert C. Lack of change in markers of presynaptic terminal abundance alongside subtle reductions in markers of presynaptic terminal plasticity in prefrontal cortex of schizophrenia patients. Biol Psychiatry 2011; 69:71-9. [PMID: 21145444 PMCID: PMC3001685 DOI: 10.1016/j.biopsych.2010.09.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 09/14/2010] [Accepted: 09/16/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND Reduced synaptic connectivity in frontal cortex may contribute to schizophrenia symptoms. While altered messenger RNA (mRNA) and protein expression of various synaptic genes have been found, discrepancies between studies mean a generalizable synaptic pathology has not been identified. METHODS We determined if mRNAs encoding presynaptic proteins enriched in inhibitory (vesicular gamma-aminobutyric acid transporter [VGAT] and complexin 1) and/or excitatory (vesicular glutamate transporter 1 [VGluT1] and complexin 2) terminals are altered in the dorsolateral prefrontal cortex of subjects with schizophrenia (n = 37 patients, n = 37 control subjects). We also measured mRNA expression of markers associated with synaptic plasticity/neurite outgrowth (growth associated protein 43 [GAP43] and neuronal navigators [NAVs] 1 and 2) and mRNAs of other synaptic-associated proteins previously implicated in schizophrenia: dysbindin and vesicle-associated membrane protein 1 (VAMP1) mRNAs using quantitative polymerase chain reaction. RESULTS No significant changes in complexin 1, VGAT, complexin 2, VGluT1, dysbindin, NAV2, or VAMP1 mRNA expression were found; however, expression of mRNAs associated with plasticity/cytoskeletal modification (GAP43 and NAV1) was reduced in schizophrenia. Although dysbindin mRNA did not differ in schizophrenia compared with control subjects, dysbindin mRNA positively correlated with GAP43 and NAV1 in schizophrenia but not in control subjects, suggesting low levels of dysbindin may be linked to reduced plasticity in the disease state. No relationships between three dysbindin genetic polymorphisms previously associated with dysbindin mRNA levels were found. CONCLUSIONS A reduction in the plasticity of synaptic terminals supports the hypothesis that their reduced modifiability may contribute to neuropathology and working memory deficits in schizophrenia.
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Affiliation(s)
- Samantha J. Fung
- Schizophrenia Research Institute, Sydney, Australia,Neuroscience Research Australia, Sydney, Australia,School of Medical Sciences, University of New South Wales, Sydney, Australia
| | | | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, Australia,Neuroscience Research Australia, Sydney, Australia,School of Psychiatry, University of New South Wales, Australia
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Abstract
The neurodegenerative aspect of schizophrenia presupposes gene-environmental interactions involving chromosomal abnormalities and obstetric/perinatal complications that culminate in predispositions that impart a particular vulnerability for drastic and unpredictable precipitating factors, such as stress or chemical agents. The notion of a neurodevelopmental progression to the disease state implies that early developmental insults, with neurodegenerative proclivities, evolve into structural brain abnormalities involving specific regional circuits and neurohumoral agents. This neurophysiological orchestration is expressed in the dysfunctionality observed in premorbid signs and symptoms arising in the eventual diagnosis, as well as the neurobehavioral deficits reported from animal models of the disorder. The relative contributions of perinatal insults, neonatal ventral hippocampus lesion, prenatal methylazoxymethanol acetate and early traumatic experience, as well as epigenetic contributions, are discussed from a neurodegenerative view of the essential neuropathology. It is implied that these considerations of factors that exert disruptive influences upon brain development, or normal aging, operationalize the central hub of developmental neuropathology around which the disease process may gain momentum. Nonetheless, the status of neurodegeneration in schizophrenia is somewhat tenuous and it is possible that brain imaging studies on animal models of the disorder, which may describe progressive alterations to cortical, limbic and ventricular structures similar to those of schizophrenic patients, are necessary to resolve the issue.
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Affiliation(s)
- Trevor Archer
- University of Gothenburg, Department of Psychology, Box 500, SE-40530, Gothenburg, Sweden.
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Jutapakdeegul N, Afadlal S, Polaboon N, Phansuwan‐Pujito P, Govitrapong P. Repeated restraint stress and corticosterone injections during late pregnancy alter GAP‐43 expression in the hippocampus and prefrontal cortex of rat pups. Int J Dev Neurosci 2009; 28:83-90. [DOI: 10.1016/j.ijdevneu.2009.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 09/01/2009] [Accepted: 09/15/2009] [Indexed: 11/26/2022] Open
Affiliation(s)
- Nuanchan Jutapakdeegul
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
| | - Szeifoul Afadlal
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
| | - Nongnuch Polaboon
- Faculty of Allied Health SciencesChristian UniversityNakornpathom73000Thailand
| | | | - Piyarat Govitrapong
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
- Center for NeuroscienceFaculty of ScienceMahidol UniversityBangkokThailand
- Department of Pharmacology, Faculty of ScienceMahidol UniversityBangkokThailand
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Proteomic analysis of membrane microdomain-associated proteins in the dorsolateral prefrontal cortex in schizophrenia and bipolar disorder reveals alterations in LAMP, STXBP1 and BASP1 protein expression. Mol Psychiatry 2009; 14:601-13. [PMID: 18268500 DOI: 10.1038/mp.2008.7] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The dorsolateral prefrontal cortex (dlpfc) is strongly implicated in the pathogenesis of schizophrenia (SCZ) and bipolar disorder (BPD) and, within this region, abnormalities in glutamatergic neurotransmission and synaptic function have been described. Proteins associated with these functions are enriched in membrane microdomains (MM). In the current study, we used two complementary proteomic methods, two-dimensional difference gel electrophoresis and one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis followed by reverse phase-liquid chromatography-tandem mass spectrometry (RP-LC-MS/MS) (gel separation liquid chromatography-tandem mass spectrometry (GeLC-MS/MS)) to assess protein expression in MM in pooled samples of dlpfc from SCZ, BPD and control cases (n=10 per group) from the Stanley Foundation Brain series. We identified 16 proteins altered in one/both disorders using proteomic methods. We selected three proteins with roles in synaptic function (syntaxin-binding protein 1 (STXBP1), brain abundant membrane-attached signal protein 1 (BASP1) and limbic system-associated membrane protein (LAMP)) for validation by western blotting. This revealed significantly increased expression of these proteins in SCZ (STXBP1 (24% difference; P<0.001), BASP1 (40% difference; P<0.05) and LAMP (22% difference; P<0.01)) and BPD (STXBP1 (31% difference; P<0.001), BASP1 (23% difference; P<0.01) and LAMP (20% difference; P<0.01)) in the Stanley brain series (n=20 per group). Further validation in dlpfc from the Harvard brain subseries (n=10 per group) confirmed increased protein expression in SCZ of STXBP1 (18% difference; P<0.0001), BASP1 (14% difference; P<0.0001) but not LAMP (20% difference; P=0.14). No significant differences in STXBP1, BASP1 or LAMP protein expression in BPD dlpfc were observed. This study, through proteomic assessments of MM in dlpfc and validation in two brain series, strongly implicates LAMP, STXBP1 and BASP1 in SCZ and supports the view of a neuritic and synaptic dysfunction in the neuropathology of SCZ.
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Early parental deprivation in the marmoset monkey produces long-term changes in hippocampal expression of genes involved in synaptic plasticity and implicated in mood disorder. Neuropsychopharmacology 2009; 34:1381-94. [PMID: 18615010 PMCID: PMC2669475 DOI: 10.1038/npp.2008.106] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In mood disorder, early stressors including parental separation are vulnerability factors, and hippocampal involvement is prominent. In common marmoset monkeys, daily parental deprivation during infancy produces a prodepressive state of increased basal activity and reactivity in stress systems and mild anhedonia that persists at least to adolescence. Here we examined the expression of eight genes, each implicated in neural plasticity and in the pathophysiology of mood disorder, in the hippocampus of these same adolescent marmosets, relative to their normally reared sibling controls. We also measured hippocampal volume. Early deprivation led to decreases in hippocampal growth-associated protein-43 (GAP-43) mRNA, serotonin 1A receptor (5-HT(1A)R) mRNA and binding ([3H]WAY100635), and to increased vesicular GABA transporter mRNA. Brain-derived neurotrophic factor (BDNF), synaptophysin, vesicular glutamate transporter 1 (VGluT1), microtubule-associated protein-2, and spinophilin transcripts were unchanged. There were some correlations with in vivo biochemical and behavioral indices, including VGluT1 mRNA with reward-seeking behavior, and serotonin 1A receptor mRNA with CSF cortisol. Early deprivation did not affect hippocampal volume. We conclude that early deprivation in a nonhuman primate, in the absence of subsequent stressors, has a long-term effect on the hippocampal expression of genes implicated in synaptic function and plasticity. The reductions in GAP-43 and serotonin 1A receptor expressions are comparable with findings in mood disorder, supporting the possibility that the latter reflect an early developmental contribution to disease vulnerability. Equally, the negative results suggest that other features of mood disorder, such as decreased hippocampal volume and BDNF expression, are related to different aspects of the pathophysiological process.
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The neonatal ventral hippocampal lesion as a heuristic neurodevelopmental model of schizophrenia. Behav Brain Res 2008; 204:295-305. [PMID: 19100784 DOI: 10.1016/j.bbr.2008.11.039] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 11/06/2008] [Accepted: 11/25/2008] [Indexed: 11/21/2022]
Abstract
Traditionally, animal models of schizophrenia were predominantly pharmacological constructs focused on phenomena linked to dopamine and glutamate neurotransmitter systems, and were created by direct perturbations of these systems. A number of developmental models were subsequently generated that allowed testing of hypotheses about the origin of the disease, mimicked a wider array of clinical and neurobiological features of schizophrenia, and opened new avenues for developing novel treatment strategies. The most thoroughly characterized (approximately 100 primary research articles) is the neonatal ventral hippocampal lesion (NVHL) model, which is the subject of this review. We highlight its advantages and limitations, and how it may offer clues about the extent to which positive, negative, cognitive, and other aspects of schizophrenia, including addiction vulnerability, represent inter-related pathophysiological mechanisms.
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Eastwood SL, Lyon L, George L, Andrieux A, Job D, Harrison PJ. Altered expression of synaptic protein mRNAs in STOP (MAP6) mutant mice. J Psychopharmacol 2007; 21:635-44. [PMID: 17050659 DOI: 10.1177/0269881106068825] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Stable tubule-only polypeptide (STOP) proteins are a family of microtubule associated proteins (MAPs) important in microtubule stabilization. Data indicating a role for microtubules in synaptic function has come from studies of the STOP null mouse, which exhibits synaptic deficits, in association with behavioural changes that are alleviated by antipsychotic treatment. These findings suggested that STOP mutant mice may be useful in studies of synaptic function, and could be especially relevant to schizophrenia, postulated to be a disorder of the synapse. Moreover, a genetic association between STOP and schizophrenia has been reported. This study aimed to further characterize synaptic alterations in STOP null and heterozygous mice. Using in situ hybridization histochemistry, the mRNA expression of three pre-synaptic (synaptophysin; growth associated protein-43 (GAP-43); vesicular glutamate transporter-1 (VGlut1)) and two post-synaptic (spinophilin; MAP2) proteins, was quantified in female STOP null (n = 7), heterozygous (n = 5) and wild type (n = 6) mice. For STOP null and heterozygous mice, synaptophysin, VGlut1, GAP-43 and spinophilin mRNAs were decreased in the hippocampus, whilst in addition in the null mice, synaptophysin, VGlut1 and spinophilin mRNAs were decreased in the cerebellum. Alterations in synaptic protein mRNA expression were also detected in the frontal and occipital cortex. MAP2 mRNA expression was unchanged in all brain regions. The profile of mRNA changes is broadly similar to that observed in schizophrenia. Together the data provide supporting evidence for a role for microtubules in synaptic function, and suggest that STOP, or other microtubule proteins, may contribute to the synaptic pathology of schizophrenia.
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Affiliation(s)
- Sharon L Eastwood
- University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford, UK.
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19
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Bolognani F, Tanner DC, Nixon S, Okano HJ, Okano H, Perrone-Bizzozero NI. Coordinated expression of HuD and GAP-43 in hippocampal dentate granule cells during developmental and adult plasticity. Neurochem Res 2007; 32:2142-51. [PMID: 17577668 DOI: 10.1007/s11064-007-9388-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 05/15/2007] [Indexed: 01/04/2023]
Abstract
Previous work from our laboratory demonstrated that the RNA-binding protein HuD binds to and stabilizes the GAP-43 mRNA. In this study, we characterized the expression of HuD and GAP-43 mRNA in the hippocampus during two forms of neuronal plasticity. During post-natal development, maximal expression of both molecules was found at P5 and their levels steadily decreased thereafter. At P5, HuD was also present in the subventricular zone, where it co-localized with doublecortin. In the adult hippocampus, the basal levels of HuD and GAP-43 were lower than during development but were significantly increased in the dentate gyrus after seizures. The function of HuD in GAP-43 gene expression was confirmed using HuD-KO mice, in which the GAP-43 mRNA was significantly less stable than in wild type mice. Altogether, these results demonstrate that HuD plays a role in the post-transcriptional control of GAP-43 mRNA in dentate granule cells during developmental and adult plasticity.
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Affiliation(s)
- Federico Bolognani
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA.
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20
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Tian SY, Wang JF, Bezchlibnyk YB, Young LT. Immunoreactivity of 43kDa growth-associated protein is decreased in post mortem hippocampus of bipolar disorder and schizophrenia. Neurosci Lett 2007; 411:123-7. [PMID: 17095155 DOI: 10.1016/j.neulet.2006.10.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/27/2006] [Accepted: 10/18/2006] [Indexed: 12/21/2022]
Abstract
Impairment of neuroplasticity is considered to play a role in the pathogenesis of psychiatric disorders. To further characterize the impairment of neuroplasticity in psychiatric disorders, expression of the neuronal plasticity marker 43 kDa growth-associated protein (GAP-43) was detected in postmortem hippocampal sub-regions from psychiatric patients including major depressive disorder, bipolar disorder and schizophrenia subjects, and matched control subjects. We found that GAP-43 protein levels in the hippocampal hilar region were significantly lower in bipolar disorder and schizophrenia subjects than in control subjects. We also found that GAP-43 protein levels in the inner molecular layer of the dentate gyrus and the stratum radiatum of CA2 region were reduced in a trend in bipolar disorder and schizophrenia subjects when compared with control subjects. These results suggest that impairment of neuroplasticity may occur in the hippocampus of bipolar disorder and schizophrenia patients.
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Affiliation(s)
- Simon Y Tian
- The Vivian Rakoff Mood Disorders Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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21
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Phillips LJ, McGorry PD, Garner B, Thompson KN, Pantelis C, Wood SJ, Berger G. Stress, the hippocampus and the hypothalamic-pituitary-adrenal axis: implications for the development of psychotic disorders. Aust N Z J Psychiatry 2006; 40:725-41. [PMID: 16911747 DOI: 10.1080/j.1440-1614.2006.01877.x] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The experience of stress is commonly implicated in models of the onset of psychotic disorders. However, prospective studies investigating associations between biological markers of stress and the emergence of psychotic disorders are limited and inconclusive. One biological system proposed as the link between the psychological experience of stress and the development of psychosis is the Hypothalamic-Pituitary-Adrenal (HPA) axis. This paper summarizes and discusses evidence supporting a role for HPA-axis dysfunction in the early phase of schizophrenia and related disorders. METHOD A selective review of psychiatric and psychological research on stress, coping, HPA-axis, the hippocampus and psychotic disorders was performed, with a particular focus on the relationship between HPA-axis dysfunction and the onset of psychotic disorders. RESULTS Individual strands of past research have suggested that the HPA-axis is dysfunctional in at least some individuals with established psychotic disorders; that the hippocampus is an area of the brain that appears to be implicated in the onset and maintenance of psychotic disorders; and that an increase in the experience of stress precedes the onset of a psychotic episode in some individuals. Models of the onset and maintenance of psychotic disorders that link these individual strands of research and strategies for examining these models are proposed in this paper. CONCLUSIONS The current literature provides some evidence that the onset of psychotic disorders may be associated with a higher rate of stress and changes to the hippocampus. It is suggested that future research should investigate whether a relationship exists between psychological stress, HPA-axis functioning and the hippocampus in the onset of these disorders. Longitudinal assessment of these factors in young people at 'ultra' high risk of psychosis and first-episode psychosis cohorts may enhance understanding of the possible interaction between them in the early phases of illness.
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Affiliation(s)
- Lisa J Phillips
- Department of Psychology, University of Melbourne, Parkville, Victoria, Australia.
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22
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Iwata M, Shirayama Y, Ishida H, Kawahara R. Hippocampal synapsin I, growth-associated protein-43, and microtubule-associated protein-2 immunoreactivity in learned helplessness rats and antidepressant-treated rats. Neuroscience 2006; 141:1301-13. [PMID: 16814933 DOI: 10.1016/j.neuroscience.2006.04.060] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 04/04/2006] [Accepted: 04/26/2006] [Indexed: 11/21/2022]
Abstract
Learned helplessness rats are thought to be an animal model of depression. To study the role of synapse plasticity in depression, we examined the effects of learned helplessness and antidepressant treatments on synapsin I (a marker of presynaptic terminals), growth-associated protein-43 (GAP-43; a marker of growth cones), and microtubule-associated protein-2 (MAP-2; a marker of dendrites) in the hippocampus by immunolabeling. (1) Learned helplessness rats showed significant increases in the expression of synapsin I two days after the attainment of learned helplessness, and significant decreases in the protein expression eight days after the achievement of learned helplessness. Subchronic treatment of naïve rats with imipramine or fluvoxamine significantly decreased the expression of synapsin I. (2) Learned helplessness increased the expression of GAP-43 two days and eight days after learned helplessness training. Subchronic treatment of naïve rats with fluvoxamine but not imipramine showed a tendency to decrease the expression of synapsin I. (3) Learned helplessness rats showed increased expression of MAP-2 eight days after the attainment of learned helplessness. Naïve rats subchronically treated with imipramine showed a tendency toward increased expression of MAP-2, but those treated with fluvoxamine did not. These results indicate that the neuroplasticity-related proteins synapsin I, GAP-43, and MAP-2 may play a role in the pathophysiology of depression and the mechanisms of antidepressants.
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Affiliation(s)
- M Iwata
- Department of Neuropsychiatry, Faculty of Medicine, Tottori University, 36-1 Nishi-machi, Yonago, Tottori 683-8504, Japan
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23
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Eastwood SL, Harrison PJ. Decreased expression of vesicular glutamate transporter 1 and complexin II mRNAs in schizophrenia: further evidence for a synaptic pathology affecting glutamate neurons. Schizophr Res 2005; 73:159-72. [PMID: 15653259 DOI: 10.1016/j.schres.2004.05.010] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 05/24/2004] [Accepted: 05/24/2004] [Indexed: 01/11/2023]
Abstract
Synaptic protein gene expression is altered in schizophrenia. In the hippocampal formation there may be particular involvement of glutamatergic neurons and their synapses, but overall the profile remains unclear. In this in situ hybridization histochemistry (ISHH) study, we examined four informative synaptic protein transcripts: vesicular glutamate transporter (VGLUT) 1, VGLUT2, complexin I, and complexin II, in dorsolateral prefrontal cortex (DPFC), superior temporal cortex (STC), and hippocampal formation, in 13 subjects with schizophrenia and 18 controls. In these areas, VGLUT1 and complexin II are expressed primarily by excitatory neurons, whereas complexin I is mainly expressed by inhibitory neurons. In schizophrenia, VGLUT1 mRNA was decreased in hippocampal formation and DPFC, complexin II mRNA was reduced in DPFC and STC, and complexin I mRNA decreased in STC. Hippocampal VGLUT1 mRNA declined with age selectively in the schizophrenia group. VGLUT2 mRNA was not quantifiable due to its low level. The data provide additional evidence for a synaptic pathology in schizophrenia, in terms of a reduced expression of three synaptic protein genes. In the hippocampus, the loss of VGLUT1 mRNA supports data indicating that glutamatergic presynaptic deficits are prominent, whereas the pattern of results in temporal and frontal cortex suggests broadly similar changes may affect inhibitory and excitatory neurons. The impairment of synaptic transmission implied by the synaptic protein reductions may contribute to the dysfunction of cortical neural circuits that characterises the disorder.
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Affiliation(s)
- S L Eastwood
- Department of Psychiatry, University of Oxford, Warneford Hospital, Neurosciences Building, Oxford OX3 7JX, UK.
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24
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Chambers JS, Thomas D, Saland L, Neve RL, Perrone-Bizzozero NI. Growth-associated protein 43 (GAP-43) and synaptophysin alterations in the dentate gyrus of patients with schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:283-90. [PMID: 15694236 DOI: 10.1016/j.pnpbp.2004.11.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2004] [Indexed: 11/17/2022]
Abstract
Growth-associated protein 43 (GAP-43) expression is critical for the proper establishment of neural circuitry, a process thought to be disrupted in schizophrenia. Previous work from our laboratory demonstrated decreased GAP-43 levels in post-mortem tissue from the entire hippocampal formation of affected individuals. In the present study, we used immunocytochemical techniques to localize alterations in GAP-43 protein to specific synapses. GAP-43 distribution was compared to that of synaptophysin, another synaptic protein known to be altered in schizophrenia. The levels and distribution of GAP-43 and synaptophysin proteins were measured in the dentate gyrus of subjects with schizophrenia and sex-, age-, and postmortem interval-matched normal controls and subjects with bipolar disorder. Tissue from subjects was provided by the Harvard Brain Tissue Resource Center. In control subjects, GAP-43 immunostaining was prominent in synaptic terminals in the inner molecular layer and hilar region. Subjects with schizophrenia had significant decreases in GAP-43 immunoreactivity in the hilus (p<0.05, paired t-test) and inner molecular layer (p<0.05, paired t-test) but not in the outer molecular layer. In the same tissues, synaptophysin immunoreactivity was significantly reduced in both the inner and outer molecular layers of the dentate gyrus (both p<0.01 by paired t-test), but not in the hilus. In contrast to patients with schizophrenia, GAP-43 and synaptophysin levels in subjects with bipolar disorder did not differ from controls. Given the relationship of GAP-43 and synaptophysin with the development and plasticity of synaptic connections, the observed alterations in the hippocampus of patients with schizophrenia may be related to cognitive deficits associated with this illness.
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Affiliation(s)
- Jessie S Chambers
- Department of Neurosciences, University of New Mexico School of Medicine, 915 Camino de Salud NE, Albuquerque, NM 87131, USA
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25
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Frost DO, Tamminga CA, Medoff DR, Caviness V, Innocenti G, Carpenter WT. Neuroplasticity and schizophrenia. Biol Psychiatry 2004; 56:540-3. [PMID: 15476682 DOI: 10.1016/j.biopsych.2004.01.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Revised: 01/08/2004] [Accepted: 01/14/2004] [Indexed: 11/18/2022]
Abstract
This article's title is also the name of a workshop sponsored by the International Congress on Schizophrenia Research that was focused on an appraisal of the potential role of neuroplastic processes in the etiology or course of schizophrenia. The workshop brought together clinical investigators of schizophrenia and basic scientists who study various aspects of neuroplasticity, including central nervous system (CNS) development, learning and memory, and drug action. The goal was to identify special opportunities to advance knowledge and understanding of schizophrenia pathology, treatment, or prevention by applying neuroplasticity concepts as a framework to theories of the illness. Although the focus of this workshop was schizophrenia, the phenomena considered are pertinent to other disorders, such as depression and drug abuse.
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Affiliation(s)
- Douglas O Frost
- Department of Pharmacology and Experimental Therapeutics, Baltimore, Maryland, USA
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26
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Harrison PJ. The hippocampus in schizophrenia: a review of the neuropathological evidence and its pathophysiological implications. Psychopharmacology (Berl) 2004; 174:151-62. [PMID: 15205886 DOI: 10.1007/s00213-003-1761-y] [Citation(s) in RCA: 506] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Accepted: 11/25/2003] [Indexed: 01/17/2023]
Abstract
This paper puts the case for the hippocampus as being central to the neuropathology and pathophysiology of schizophrenia. The evidence comes from a range of approaches, both in vivo (neuropsychology, structural and functional imaging) and post mortem (histology, morphometry, gene expression, and neurochemistry). Neuropathologically, the main positive findings concern neuronal morphology, organisation, and presynaptic and dendritic parameters. The results are together suggestive of an altered synaptic circuitry or "wiring" within the hippocampus and its extrinsic connections, especially with the prefrontal cortex. These changes plausibly represent the anatomical component of the aberrant functional connectivity that underlies schizophrenia. Glutamatergic pathways are prominently but not exclusively affected. Changes appear somewhat greater in the left hippocampus than the right, and CA1 is relatively uninvolved compared to other subfields. Hippocampal pathology in schizophrenia may be due to genetic factors, aberrant neurodevelopment, and/or abnormal neural plasticity; it is not due to any recognised neurodegenerative process. Hippocampal involvement is likely to be associated with the neuropsychological impairments of schizophrenia rather than with its psychotic symptoms.
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Affiliation(s)
- Paul J Harrison
- Department of Psychiatry, Neurosciences Building, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK.
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27
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Abstract
The present paper demonstrates a remarkable pervasiveness of underlying Ca(2+) signaling motifs among the available biochemical findings in schizophrenic patients and among the major molecular hypotheses of this disease. In addition, the paper reviews the findings suggesting that Ca(2+) is capable of inducing structural and cognitive deficits seen in schizophrenia. The evidence of the ability of antipsychotic drugs to affect Ca(2+) signaling is also presented. Based on these data, it is proposed that altered Ca(2+) signaling may constitute the central unifying molecular pathology in schizophrenia. According to this hypothesis schizophrenia can result from alterations in multiple proteins and other molecules as long as these alterations lead to abnormalities in certain key aspects of intracellular Ca(2+) signaling cascades.
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Affiliation(s)
- Michael S Lidow
- Department of Biomedical Sciences and Program of Neuroscience, University of Maryland, Room 5-A-12, HHH, 666 W. Baltimore Street, Baltimore, MD 21201, USA.
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28
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Halim ND, Weickert CS, McClintock BW, Hyde TM, Weinberger DR, Kleinman JE, Lipska BK. Presynaptic proteins in the prefrontal cortex of patients with schizophrenia and rats with abnormal prefrontal development. Mol Psychiatry 2003; 8:797-810. [PMID: 12931207 DOI: 10.1038/sj.mp.4001319] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dysfunction of the prefrontal cortex in schizophrenia may be associated with abnormalities in synaptic structure and/or function and reflected in altered concentrations of proteins in presynaptic terminals and involved in synaptic plasticity (synaptobrevin/ vesicle-associated membrane protein (VAMP), synaptosomal-associated protein-25 (SNAP-25), syntaxin, synaptophysin and growth-associated protein-43 (GAP-43)). We examined the immunoreactivity of these synapse-associated proteins via quantitative immunoblotting in the prefrontal cortex of patients with schizophrenia (n=18) and in normal controls (n=23). We also tested the stability of these proteins across successive post-mortem intervals in rat brains (at 0, 3, 12, 24, 48, and 70 h). To investigate whether experimental manipulation of prefrontal cortical development in the rat alters prefrontal synaptic protein levels, we lesioned the ventral hippocampus of rats on postnatal day 7 and measured immunoreactivity of presynaptic proteins in the prefrontal cortex on postnatal day 70. VAMP immunoreactivity was lower in the schizophrenic patients by 22% (P<0.03). There were no differences in the immunoreactivity of any other proteins measured in schizophrenic patients as compared to the matched controls. Proteins were fairly stable up to 24 h and thereafter the abundance of most proteins examined was significantly reduced (falling to as low as 20% of baseline levels at 48-70 h). VAMP immunoreactivity was higher in the lesioned rats as compared to sham controls by 22% (P&<0.03). There were no significant differences between the lesioned rats and sham animals in any other presynaptic protein. These data suggest that apparently profound prefrontal cortical dysfunction in schizophrenia, as well as in an animal model of schizophrenia, may exist without gross changes in the abundance of many synaptic proteins but discrete changes in selected presynaptic molecules may be present.
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Affiliation(s)
- N D Halim
- Clinical Brain Disorders Branch, Intramural Research Program, National Institutes of Mental Health, NIH, Bethesda, MD, USA
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29
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Webster MJ, Knable MB, O'Grady J, Orthmann J, Weickert CS. Regional specificity of brain glucocorticoid receptor mRNA alterations in subjects with schizophrenia and mood disorders. Mol Psychiatry 2003; 7:985-94, 924. [PMID: 12399952 DOI: 10.1038/sj.mp.4001139] [Citation(s) in RCA: 292] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2001] [Revised: 12/07/2001] [Accepted: 03/05/2002] [Indexed: 01/24/2023]
Abstract
Glucocorticoid receptors (GR) mediate the direct effects of glucocorticoids released in response to stress and the regulation of the hypothalamic-pituitary-adrenocortical (HPA) system through a negative feedback mechanism. Individuals with major mental illness, who often exhibit hypercortisolemia, may have down-regulated levels of GR mRNA. In situ hybridization for GR mRNA was performed on post-mortem specimens from patients suffering from depression, bipolar disorder, schizophrenia and from normal controls (n = 15 per group). In frontal cortex, GR mRNA levels were decreased in layers III-VI in the subjects with depression and schizophrenia. In inferior temporal cortex, GR mRNA levels were decreased in layer IV in all three diagnostic groups. In the entorhinal cortex, GR mRNA levels were decreased in layers III and VI in the bipolar group. In hippocampus, GR mRNA levels were reduced in the dentate gyrus, CA(4), CA(3) and CA(1) in the schizophrenia group. In the subiculum, GR mRNA levels were reduced in the bipolar group. These results suggest that GR dysregulation occurs in all three major psychiatric illnesses with variability according to anatomical site. The severity and heterogeneity of this reduction may underlie some of the clinical heterogeneity seen in these disorders.
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Affiliation(s)
- M J Webster
- Stanley Foundation Laboratory of Brain Research, Department of Psychiatry, Uniformed Services University of Health Sciences, Bethesda, MD 20814-4799, USA.
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30
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Abstract
Schizophrenia is a common and debilitating illness, characterized by chronic psychotic symptoms and psychosocial impairment that exact considerable human and economic costs. The literature in electronic databases as well as citations and major articles are reviewed with respect to the phenomenology, pathology, treatment, genetics and neurobiology of schizophrenia. Although studied extensively from a clinical, psychological, biological and genetic perspective, our expanding knowledge of schizophrenia provides only an incomplete understanding of this complex disorder. Recent advances in neuroscience have allowed the confirmation or refutation of earlier findings in schizophrenia, and permit useful comparisons between the different levels of organization from which the illness has been studied. Schizophrenia is defined as a clinical syndrome that may include a collection of diseases that share a common presentation. Genetic factors are the most important in the etiology of the disease, with unknown environmental factors potentially modulating the expression of symptoms. Schizophrenia is a complex genetic disorder in which many genes may be implicated, with the possibility of gene-gene interactions and a diversity of genetic causes in different families or populations. A neurodevelopmental rather than degenerative process has received more empirical support as a general explanation of the pathophysiology, although simple dichotomies are not particularly helpful in such a complicated disease. Structural brain changes are present in vivo and post-mortem, with both histopathological and imaging studies in overall agreement that the temporal and frontal lobes of the cerebral cortex are the most affected. Functional imaging, neuropsychological testing and clinical observation are also generally consistent in demonstrating deficits in cognitive ability that correlate with abnormalities in the areas of the brain with structural abnormalities. The dopamine and other neurotransmitter systems are certainly involved in the treatment or modulation of psychotic symptoms. These broad findings represent the distillation of a large body of disparate data, but firm and specific findings are sparse, and much about schizophrenia remains unknown.
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Affiliation(s)
- Albert Hung Choy Wong
- Centre for Addiction and Mental Health, 250 College Street, M5T 1R8, Toronto, Ont., Canada.
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Eastwood SL, Law AJ, Everall IP, Harrison PJ. The axonal chemorepellant semaphorin 3A is increased in the cerebellum in schizophrenia and may contribute to its synaptic pathology. Mol Psychiatry 2003; 8:148-55. [PMID: 12610647 DOI: 10.1038/sj.mp.4001233] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The neuropathological features of schizophrenia are suggestive of a developmentally induced impairment of synaptic connectivity. Semaphorin 3A (sema3A) might contribute to this process because it is a secreted chemorepellant which regulates axonal guidance. We have investigated sema3A in the cerebellum (an area in which expression persists in adulthood), and measured its abundance in 16 patients with schizophrenia and 16 controls. In adults, sema3A was predominantly localized to the inner part of the molecular layer neuropil, whereas infants and rats showed greater labelling of Purkinje cell bodies. Sema3A was increased in schizophrenia, as shown by enzyme-linked immunosorbent assay (+28%; P<0.05) and immunohistochemistry (+45%; P<0.01). We also measured reelin mRNA, since reelin is involved in related developmental processes and is decreased in other brain regions in schizophrenia. Reelin mRNA showed a trend reduction in the subjects with schizophrenia (-26%; P=0.07) and, notably, was negatively correlated with sema3A. Sema3A also correlated negatively with synaptophysin and complexin II mRNAs. The results show that sema3A is elevated in schizophrenia, and is associated with downregulation of genes involved in synaptic formation and maintenance. In this respect, sema3A appears to contribute to the synaptic pathology of schizophrenia, perhaps via ongoing effects of persistent sema3A elevation on synaptic plasticity. The findings are consistent with an early neurodevelopmental origin for the disorder, and the reciprocal changes in sema3A and reelin may be indicative of a pathogenic mechanism that affects the balance between trophic and inhibitory factors regulating synaptogenesis.
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Affiliation(s)
- S L Eastwood
- Departments of Psychiatry and Clinical Neurology, Warneford Hospital, University of Oxford, Oxford OX3 7JX, UK
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Lipska BK, Weinberger DR. A neurodevelopmental model of schizophrenia: neonatal disconnection of the hippocampus. Neurotox Res 2002; 4:469-475. [PMID: 12754160 DOI: 10.1080/1029842021000022089] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the context of our current knowledge about schizophrenia, heuristic models of psychiatric disorders may be used to test the plausibility of theories developed on the basis of new emerging biological findings, explore mechanisms of schizophrenia-like phenomena, and develop potential new treatments. In a series of studies, we have shown that neonatal excitotoxic lesions of the rat ventral hippocampus (VH) may serve as a heuristic model. The model appears to mimic a spectrum of neurobiological and behavioral features of schizophrenia, including functional pathology in presumably critical brain regions interconnected with the hippocampal formation and targeted by antipsychotic drugs - the striatum/nucleus accumbens and the prefrontal cortex, and leads in adolescence or early adulthood to the emergence of abnormalities in a number of dopamine related behaviors. Moreover, our data show that even transient inactivation of the ventral hippocampus during a critical period of development, that produces subtle, if any, anatomical changes in the hippocampus, may be sufficient to disrupt normal maturation of the prefrontal cortex (and perhaps, other interconnected late maturing regions) and trigger behavioral changes similar to those observed in animals with the permanent excitotoxic lesion. These results represent a potential new model of aspects of schizophrenia without a gross anatomical lesion.
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Affiliation(s)
- Barbara K. Lipska
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, NIH, IRP, 10 Center Drive, Bldg.10, Rm. 4N306, Bethesda, MD 20892
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Vinogradova OS. Hippocampus as comparator: role of the two input and two output systems of the hippocampus in selection and registration of information. Hippocampus 2002; 11:578-98. [PMID: 11732710 DOI: 10.1002/hipo.1073] [Citation(s) in RCA: 370] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Processing of multimodal sensory information by the morphological subdivisions of the hippocampus and its input and output structures was investigated in unanesthetized rabbits by extracellular recording of neuronal activity. Analysis shows principal differences between CA3 neurons with uniform multimodal, mainly inhibitory, rapidly habituating sensory responses, and CA1-subicular neurons, substantial parts of which have phasic reactions and patterned on-responses, depending on the characteristics of the stimuli. These differences result from the organization of the afferent inputs to CA1 and CA3. Analysis of neuronal responses in sources of hippocampal inputs, their electrical stimulation, and chronic disconnection show the greater functional significance of the brain-stem reticular input for tonic responses characteristic of CA3. This input signal before entering the hippocampus is additionally preprocessed at the MS-DB relay, where it becomes more uniform and frequency-modulated in the range of theta-rhythm. It is shown that the new sensory stimuli produce inhibitory reset, after which synchronized theta-modulation is triggered. Other stimuli, appearing at the background of the ongoing theta, do not evoke any responses of the hippocampal neurons. Thus, theta-modulation can be regarded as a mechanism of attention, which prolongs response to a selected stimulus and simultaneously protects its processing against interference. The cortical input of the hippocampus introduces highly differentiated information analyzed at the highest levels of the neocortex through the intermediary of the entorhinal cortex and presubiculum. However, only CA1-subiculum receives this information directly; before its entrance into CA3, it is additionally preprocessed at the FD relay, where the secondary simplification of signals occurs. As a result, CA3 receives by its two inputs (MS-DB and FD) messages just about the presence and level of input signals in each of them, and performs relatively simple functions of determination of match/mismatch of their weights. For this comparator system, the presence of signal only in the reticulo-septal input is equivalent to quality of novelty. The cortical signal appears with some delay, after its analysis in the neocortex and shaping in the prehippocampal structures; besides, it is gradually increased due to LTP-like incremental changes in PP and mossy fiber synapses. The CA3 neurons with potentiated synapses of cortical input do not respond to sensory stimuli; that is, the increased efficacy of the cortical signals can be regarded as "familiarity" of a signal, terminating the reactive state of the CA3 neurons. The integrity of both inputs is necessary for gradual habituation of sensory responses in the hippocampus. The output signals of CA3 following in the precommissural fornix to the output relay-LS nucleus and to the brain-stem structures have strong regulatory influence on the level of brain activity (arousal), which is an important condition for processing and registration of information. The primary targets of this output signal are raphe nuclei, which suppress activity of the ascending excitatory RF. In the background state, activity of the CA3 neurons through the intermediary of raphe keeps RF under tonic inhibitory control. Inhibition of the majority of CA3 pyramidal neurons during a novel stimulus action decreases the volume of its output signal to raphe and releases RF from tonic inhibition (increase in level of activity of the forebrain, arousal). When the responses of CA3 neurons habituate, the initial high background activity is reinstated, as well as tonic suppression of RF. Analysis of the second output of CA3 (by Schaffer's collaterals to CA1) shows that activity in this pathway can block access of cortical signals from PP to CA1 neurons by action upon the local system of inhibitory neurons, or by shunting the propagation of signals in apical dendrites. Thus, CA3 can act as a filter controlling the information transmission by CA1; such transmission at any given moment is allowed only in those CA1 neurons which receive SC from CA3 neurons, responding to the sensory stimulus by suppression of their activity. Disconnection of the CA3 output fibers results in disappearance of habituation in all its target structures (raphe, RF, CA1). The output signal of CA1-subiculum follows by postcommissural fornix to the chain of structures of the main limbic circuit: mammillary bodies (medial nucleus), anterior thalamic nuclei (mainly antero-ventral nucleus), and cingulate limbic cortex (mainly posterior area). In each of these links, the signal is additionally processed. Habituation is nearly absent in these structures; instead, st
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Affiliation(s)
- O S Vinogradova
- Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics, Puschino, Moscow District, Russia
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Harrison PJ, Eastwood SL. Neuropathological studies of synaptic connectivity in the hippocampal formation in schizophrenia. Hippocampus 2002; 11:508-19. [PMID: 11732704 DOI: 10.1002/hipo.1067] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cytoarchitectural changes in the hippocampal formation have been prominent among the various neuropathological abnormalities reported in schizophrenia. Replicated positive findings include decreased neuronal size and alterations in presynaptic and dendritic markers. These findings, in the absence of neurodegenerative changes, suggest that there are alterations in the neural circuitry in schizophrenia. These may represent the anatomical correlate of the aberrant functional connectivity described in neuroimaging studies, which in turn contributes to the psychotic and cognitive symptomatology of the disorder. The identity of the affected hippocampal circuits remains unclear; there is evidence for both glutamatergic and GABAergic involvement, and perhaps for a gradient of pathology in which changes are most apparent in CA4 and the subiculum, and least in CA1. The data, their interpretation, and their limitations are discussed, with particular emphasis upon molecular and immunological studies of synaptic protein gene expression.
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Affiliation(s)
- P J Harrison
- Department of Psychiatry, University of Oxford, UK.
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35
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Abstract
Rats with neonatal excitotoxic damage of the ventral hippocampus display in adulthood a variety of abnormalities reminiscent of schizophrenia and are used as an animal model of this disorder. In the present study, we hypothesized that transient inactivation of ventral hippocampal activity during a critical developmental period may be sufficient to disrupt normal maturation of relevant brain systems and produce similar lasting behavioral changes. We infused tetrodotoxin (TTX) or artificial CSF into the ventral hippocampus on postnatal day 7 (P7) and assessed behavioral changes in response to stress, amphetamine, and (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate in juvenile (P35) and young adult (P56) rats. In adulthood, rats infused neonatally with TTX displayed motor hyperactivity after pharmacological stimulation and after stress compared with sham controls. Analogous TTX infusions in adult animals did not alter these behaviors later in life. These data suggest that transient loss of ventral hippocampal function during a critical time in maturation of intracortical connections permanently changes the development of neural circuits mediating certain dopamine- and NMDA-related behaviors. These results represent a potential new model of aspects of schizophrenia without involving a gross anatomic lesion.
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36
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Abstract
The Neurodevelopmental Hypothesis of schizophrenia suggests that interaction between genetic and environmental events occurring during critical early periods in neuronal growth may negatively influence the way by which nerve cells are laid down, differentiated and selectively culled by apoptosis. Recent advances offer insights into the regulation of brain development. The Wnt family of genes plays a central role in normal brain development. Activation of the Wnt cascade leads to inactivation of glycogen synthase kinase-3beta (GSK-3beta), accumulation and activation of beta-catenin and expression of genes involved in neuronal development. Alteration in the Wnt transduction cascade, which may represent an aberrant neurodevelopment in schizophrenia, is discussed. Programmed cell death is also an essential component of normal brain development. Abnormal neuronal distribution found in schizophrenic patients' brains may imply aberrant programmed cell death. GSK-3 participates in the signal transduction cascade of apoptosis. The possible role of aberrant GSK-3 in the etiology of schizophrenia is discussed.
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Affiliation(s)
- Nitsan Kozlovsky
- Stanley Foundation Research Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheva, Israel
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Papageorgiou C, Kontaxakis VP, Havaki-Kontaxaki BJ, Stamouli S, Vasios C, Asvestas P, Matsopoulos GK, Kontopantelis E, Rabavilas A, Uzunoglu N, Christodoulou GN. Impaired P600 in neuroleptic naive patients with first-episode schizophrenia. Neuroreport 2001; 12:2801-6. [PMID: 11588580 DOI: 10.1097/00001756-200109170-00010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Deficits of working memory (WM) are recognized as an important pathological feature in schizophrenia. Since the P600 component of event related potentials has been hypothesized that represents aspects of second-pass parsing processes of information processing, and is related to WM, the present study focuses on P600 elicited during a WM test in drug-naive first-episode schizophrenics (FES) compared to healthy controls. We examined 16 drug-naive first-episode schizophrenic patients and 23 healthy controls matched for age and sex. Compared with controls schizophrenic patients showed reduced P600 amplitude on left temporoparietal region and increased P600 amplitude on left occipital region. With regard to the latency, the patients exhibited significantly prolongation on right temporoparietal region. The obtained pattern of differences classified correctly 89.20% of patients. Memory performance of patients was also significantly impaired relative to controls. Our results suggest that second-pass parsing process of information processing, as indexed by P600, elicited during a WM test, is impaired in FES. Moreover, these findings lend support to the view that the auditory WM in schizophrenia involves or affects a circuitry including temporoparietal and occipital brain areas.
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Affiliation(s)
- C Papageorgiou
- Department of Psychiatry, Eginition Hospital, 74 Vas. Sophias Ave., Athens 11528, Greece
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38
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Abstract
Recent advances in experimental genomics, coupled with the wealth of sequence information available for a variety of organisms, have the potential to transform the way pharmacological research is performed. At present, high-density DNA microarrays allow researchers to quickly and accurately quantify gene-expression changes in a massively parallel manner. Although now well established in other biomedical fields, such as cancer and genetics research, DNA microarrays have only recently begun to make significant inroads into pharmacology. To date, the major focus in this field has been on the general application of DNA microarrays to toxicology and drug discovery and design. This review summarizes the major microarray findings of relevance to neuropsychopharmacology, as a prelude to the design and analysis of future basic and clinical microarray experiments. The ability of DNA microarrays to monitor gene expression simultaneously in a large-scale format is helping to usher in a post-genomic age, where simple constructs about the role of nature versus nurture are being replaced by a functional understanding of gene expression in living organisms.
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Affiliation(s)
- E R Marcotte
- Douglas Hospital Research Centre, Dept of Psychiatry, Faculty of Medicine, McGill University, Montreal, Quebec, Canada H4H 1R3
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Eastwood SL, Harrison PJ. Synaptic pathology in the anterior cingulate cortex in schizophrenia and mood disorders. A review and a Western blot study of synaptophysin, GAP-43 and the complexins. Brain Res Bull 2001; 55:569-78. [PMID: 11576753 DOI: 10.1016/s0361-9230(01)00530-5] [Citation(s) in RCA: 213] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
There are several reports of ultrastructural and protein changes affecting synapses in the anterior cingulate cortex in schizophrenia. Altered cytoarchitecture has also been described in this region in schizophrenia as well as in mood disorders. In this paper we review the literature and present a new study investigating synaptic abnormalities in the anterior cingulate cortex (area 24) in the Stanley Foundation brain series. We used Western blotting to assess four synaptic proteins: synaptophysin, growth-associated protein-43 (GAP-43), complexin I and complexin II, which inform about somewhat different aspects of the synaptic circuitry. Synaptophysin, complexin II and GAP-43 were reduced in bipolar disorder. The decreases correlated with the duration of illness and tended to be greater in subjects without a family history. Complexin II was also reduced in major depression. Complexin I and the housekeeping protein beta-actin did not differ between groups. None of the proteins changed significantly in schizophrenia. The results indicate the presence of a synaptic pathology in the anterior cingulate cortex in mood disorders, especially bipolar disorder. The abnormalities may contribute to the dysfunction of cingulate neural circuits. The loss of synaptophysin is suggestive of decreased synaptic density whilst the decrease in GAP-43 may denote impaired synaptic plasticity and the reduction of complexin II but not complexin I implies that the alterations particularly affect excitatory connections. The reductions may be progressive.
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Affiliation(s)
- S L Eastwood
- University Department of Psychiatry, Warneford Hospital, Oxford, UK
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Niizato K, Iritani S, Ikeda K, Arai H. Astroglial function of schizophrenic brain: a study using lobotomized brain. Neuroreport 2001; 12:1457-60. [PMID: 11388429 DOI: 10.1097/00001756-200105250-00032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The neurodevelopmental hypothesis is now being recognized as one of the most useful hypothesis for schizophrenia, and by using it, abnormalities in protein associated with neuron growth or neuronal migration have been reported. From neuron-glia interrelations in the neural development, it is important to study the function of astroglia in the schizophrenic brain. In this study, we examined the neuropathological reaction of astroglia using lobotomized brains, and a significant decrease of astroglia after artificial histological damage was observed in schizophrenic brains. We speculated that this may be due to the latent vulnerability of the dynamic function of astroglia in schizophrenia. Astroglia plays a guidance role on migration and if astroglia has latent vulnerability, we speculate that younger neurons may not sufficiently migrate during development. In further investigation of the neurodevelopmental hypothesis of schizophrenia, it will be necessary to examine the function of astroglia.
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Affiliation(s)
- K Niizato
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Japan
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Webster MJ, Shannon Weickert C, Herman MM, Hyde TM, Kleinman JE. Synaptophysin and GAP-43 mRNA levels in the hippocampus of subjects with schizophrenia. Schizophr Res 2001; 49:89-98. [PMID: 11343868 DOI: 10.1016/s0920-9964(00)00052-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synaptophysin and growth associated protein-43 (GAP-43) are synaptic proteins colocalized to the presynaptic terminal, and involved in regulating transmitter release and synaptic plasticity. Recent studies have proposed an alteration in the number of synapses in the brains of individuals with schizophrenia. As a corollary, we hypothesized that there may be an alteration in the level of mRNAs that code for synaptic proteins in brains of patients with schizophrenia. Using in situ hybridization, we investigated the levels of synaptophysin and GAP-43 mRNA in the medial temporal lobe of 10 normal subjects, 11 subjects with schizophrenia and 10 psychiatric control subjects. Synaptophysin mRNA levels were significantly reduced in several hippocampal subfields in both the schizophrenic and psychiatric control groups. GAP-43 mRNA levels were not significantly reduced in either group. The implications of these findings are discussed in relation to neuroleptic treatment and the pathophysiology of mental illness.
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Affiliation(s)
- M J Webster
- Stanley Foundation Research Program, Department of Psychiatry, Uniformed Services University for the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799, USA.
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Glantz LA, Austin MC, Lewis DA. Normal cellular levels of synaptophysin mRNA expression in the prefrontal cortex of subjects with schizophrenia. Biol Psychiatry 2000; 48:389-97. [PMID: 10978722 DOI: 10.1016/s0006-3223(00)00923-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Previous studies have reported that the 38-kd synaptic vesicle-associated protein, synaptophysin, is decreased in the prefrontal cortex of subjects with schizophrenia. METHODS To determine whether the decreased protein levels reflect diminished expression of the synaptophysin gene by prefrontal cortex neurons, we used in situ hybridization histochemistry to determine the cellular levels of synaptophysin messenger RNA in prefrontal cortex area 9 from 10 matched pairs of schizophrenic and normal control subjects. RESULTS Neither the density of neurons with detectable levels of synaptophysin messenger RNA nor the mean level of synaptophysin messenger RNA expression per neuron differed between schizophrenic and control subjects in any cortical layer. CONCLUSIONS These findings indicate that the expression of synaptophysin messenger RNA is not altered in this brain region in schizophrenia. Consequently, reduced levels of synaptophysin protein in the prefrontal cortex of subjects with schizophrenia are more likely to reflect either posttranscriptional abnormalities of synaptophysin in prefrontal cortex neurons or a diminished number of axonal projections to the prefrontal cortex from other brain regions.
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Affiliation(s)
- L A Glantz
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Gothelf D, Soreni N, Nachman RP, Tyano S, Hiss Y, Reiner O, Weizman A. Evidence for the involvement of the hippocampus in the pathophysiology of schizophrenia. Eur Neuropsychopharmacol 2000; 10:389-95. [PMID: 10974611 DOI: 10.1016/s0924-977x(00)00097-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hippocampus, a medial temporal lobe structure, is often considered to play an important role in the pathophysiology of schizophrenia. Recent developments of neuroimaging and molecular postmortem techniques have significantly increased our ability to study the role of discrete brain regions in the pathophysiology of schizophrenia. This article describes animal models, structural, histological, molecular biology, and neuropsychological evidence for the involvement of the hippocampus in the pathophysiology of schizophrenia. The major findings in schizophrenic patients are decreased volumes, hypometabolism, and cytoarchitectural abnormalities which are more robust on the left hippocampus, as well as verbal memory impairment. It is yet to be determined whether these changes are neurodevelopmental or neurodegenerative in nature. Overall, these findings indicate that there are subtle changes in the hippocampus of schizophrenic patients. More comprehensive and focused hippocampal research in schizophrenia is required to elucidate the contribution of this intriguing brain structure to the pathophysiology of schizophrenia.
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Affiliation(s)
- D Gothelf
- Geha Psychiatric Hospital, Petah Tiqwa, Israel
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Castensson A, Emilsson L, Preece P, Jazin EE. High-resolution quantification of specific mRNA levels in human brain autopsies and biopsies. Genome Res 2000; 10:1219-29. [PMID: 10958640 PMCID: PMC310892 DOI: 10.1101/gr.10.8.1219] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Quantification of mRNA levels in human cortical brain biopsies and autopsies was performed using a fluorogenic 5' nuclease assay. The reproducibility of the assay using replica plates was 97%-99%. Relative quantities of mRNA from 16 different genes were evaluated using a statistical approach based on ANCOVA analysis. Comparison of the relative mRNA levels between two groups of samples with different time postmortem revealed unchanged relative expression levels for most genes. Only CYP26A1 mRNA levels showed a significant decrease with prolonged time postmortem (p = 0.00004). Also, there was a general decrease in measured mRNA levels for all genes in autopsies compared to biopsies; however, on comparing mRNA levels after adjusting with reference genes, no significant differences were found between mRNA levels in autopsies and biopsies. This observation indicates that studies of postmortem material can be performed to reveal the relative in vivo mRNA levels of genes. Power calculations were done to determine the number of individuals necessary to detect differences in mRNA levels of 1.5-fold to tenfold using the strategy described here. This analysis showed that samples from at least 50 individuals per group, patients and controls, are required for high-resolution ( approximately twofold changes) differential expression screenings in the human brain. Experiments done on ten individuals per group will result in a resolution of approximately fivefold changes in expression levels. In general, the sensitivity and resolution of any differential expression study will depend on the sample size used and the between-individual variability of the genes analyzed.
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Affiliation(s)
- A Castensson
- Section of Medical Genetics, Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, S-751 85 Uppsala, Sweden
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45
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Abstract
The entorhinal cortex, subiculum, and hippocampus have been regions of great interest in both clinical and neuropathological investigations of schizophrenia. Postmortem studies have identified numerous abnormalities, although many remain controversial or unconfirmed. Among the cellular and molecular neuropathological findings are (1) abnormal cytoarchitecture of the entorhinal cortex characterized by poorly formed layer II neuron clusters and laminar disorganization; (2) normal neuron density but smaller neuron size in the superficial lamina of the entorhinal cortex and subiculum; (3) abnormal expression of the microtubule-associated protein MAP2 in the entorhinal cortex and subiculum; (4) aberrant glutamatergic and catecholaminergic innervation of the entorhinal cortex; (5) abnormal mRNA expression of various transcription factors, ion channels, and neurosecretory pathway-related proteins in entorhinal stellate neurons; and (6) an absence of any neurodegeneration. Altogether, these findings suggest that aberrant neurodevelopmental processes play a key role in the pathobiology of schizophrenia and provide a neuroanatomic basis for understanding many of the clinical and neuropsychological abnormalities in the disorder.
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Affiliation(s)
- S E Arnold
- Department of Psychiatry, University of Pennsylvania, Philadelphia 19104, USA.
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46
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Eastwood SL, Cairns NJ, Harrison PJ. Synaptophysin gene expression in schizophrenia. Investigation of synaptic pathology in the cerebral cortex. Br J Psychiatry 2000; 176:236-42. [PMID: 10755070 DOI: 10.1192/bjp.176.3.236] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Decreased expression of proteins such as synaptophysin in the hippocampus and prefrontal cortex in schizophrenia is suggestive of synaptic pathology. However, the overall profile of changes is unclear. AIMS To investigate synaptophysin gene expression in the cerebral cortex in schizophrenia. METHOD The dorsolateral prefrontal (Brodmann area [BA] 9/46), anterior cingulate (BA 24), superior temporal (BA 22) and occipital (BA 17) cortex were studied in two series of brains, totalling 19 cases and 19 controls. Synaptophysin was measured by immunoautoradiography and immunoblotting. Synaptophysin messenger RNA (mRNA) was measured using in situ hybridisation. RESULTS Synaptophysin was unchanged in schizophrenia, except for a reduction in BA 17 of one brain series. Synaptophysin mRNA was decreased in BA 17, and in BA 22 in the women with schizophrenia. No alterations were seen in BA 9/46. CONCLUSIONS Synaptophysin expression is decreased in some cortical areas in schizophrenia. The alterations affect the mRNA more than the protein, and have an unexpected regional distribution. The characteristics of the implied synaptic pathology remain to be determined.
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Affiliation(s)
- S L Eastwood
- University Department of Psychiatry, Warneford Hospital, Oxford
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47
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Eastwood SL, Harrison PJ. Detection and quantification of hippocampal synaptophysin messenger RNA in schizophrenia using autoclaved, formalin-fixed, paraffin wax-embedded sections. Neuroscience 1999; 93:99-106. [PMID: 10430474 DOI: 10.1016/s0306-4522(99)00096-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Most in situ hybridization histochemistry studies of messenger RNA in human brain have been carried out on frozen tissue. Recently, autoclaving has been reported to enable routinely processsed material to be used for in situ localization of messenger RNA. We have investigated whether autoclaving also permits in situ hybridization histochemistry to be used quantitatively. To do this, we targeted synaptophysin messenger RNA with a 35S-labelled oligonucleotide probe in autoclaved, formalin-fixed, paraffin wax-embedded sections of the hippocampal formation of 11 schizophrenics and 11 controls. We compared the results with those seen on frozen sections from adjacent blocks, which had been used previously to demonstrate a loss of the messenger RNA in schizophrenia. Synaptophysin messenger RNA was readily detected in the autoclaved sections. The hybridization signal correlated strongly with that seen in the frozen sections. We found a similar pattern and magnitude of decreased synaptophysin messenger RNA in schizophrenia in the autoclaved sections as we had in the frozen sections, including the selective preservation of synaptophysin messenger RNA in CA1. The reduction of synaptophysin messenger RNA was replicated when six subjects with schizophrenia not included in the earlier study were considered separately. We conclude that autoclaving renders formalin-fixed, paraffin wax-embedded sections of human brain suitable for quantitative in situ hybridization histochemistry. This has considerable implications, given the wider availability, better morphology and easier handling of fixed than frozen human brain tissue. Using this material, we confirmed the finding of decreased synaptophysin messenger RNA in the hippocampal formation in schizophrenia, furthering the evidence for synaptic pathology in this region in the disorder.
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Affiliation(s)
- S L Eastwood
- University Department of Psychiatry, Warneford Hospital, Oxford, UK
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48
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Honer WG, Falkai P, Chen C, Arango V, Mann JJ, Dwork AJ. Synaptic and plasticity-associated proteins in anterior frontal cortex in severe mental illness. Neuroscience 1999; 91:1247-55. [PMID: 10391432 DOI: 10.1016/s0306-4522(98)00679-4] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abnormalities of proteins involved in neurotransmission and neural plasticity at synapses are reported in schizophrenia, and may be markers of dysregulated neural connectivity in this illness. Studies of brain development and neural regeneration indicate a dynamic interplay between neural and oligodendroglial mechanisms in regulating synaptic plasticity and axonal sprouting. In the present study, markers of synapses (synaptophysin), plasticity (growth-associated protein-43) and oligodendrocytes (myelin basic protein) were investigated in anterior frontal cortex homogenates from individuals with schizophrenia and depression. Synaptophysin immunoreactivity was reduced in schizophrenics who died of natural causes relative to controls. Myelin basic protein immunoreactivity was decreased in both schizophrenics and depressed individuals who died by suicide. Overall, no changes were observed in growth-associated protein-43 immunoreactivity. However, a slight increase in immunoreactivity in depressed suicides relative to control was observed. These findings support the hypothesis that synaptic abnormalities are a substrate for disordered connectivity in severe mental illness, and suggest that synaptic-oligodendroglial interactions may contribute to the mechanism of dysregulation in certain cases.
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Affiliation(s)
- W G Honer
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
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Harrison PJ. The neuropathology of schizophrenia. A critical review of the data and their interpretation. Brain 1999; 122 ( Pt 4):593-624. [PMID: 10219775 DOI: 10.1093/brain/122.4.593] [Citation(s) in RCA: 1060] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Despite a hundred years' research, the neuropathology of schizophrenia remains obscure. However, neither can the null hypothesis be sustained--that it is a 'functional' psychosis, a disorder with no structural basis. A number of abnormalities have been identified and confirmed by meta-analysis, including ventricular enlargement and decreased cerebral (cortical and hippocampal) volume. These are characteristic of schizophrenia as a whole, rather than being restricted to a subtype, and are present in first-episode, unmedicated patients. There is considerable evidence for preferential involvement of the temporal lobe and moderate evidence for an alteration in normal cerebral asymmetries. There are several candidates for the histological and molecular correlates of the macroscopic features. The probable proximal explanation for decreased cortical volume is reduced neuropil and neuronal size, rather than a loss of neurons. These morphometric changes are in turn suggestive of alterations in synaptic, dendritic and axonal organization, a view supported by immunocytochemical and ultrastructural findings. Pathology in subcortical structures is not well established, apart from dorsal thalamic nuclei, which are smaller and contain fewer neurons. Other cytoarchitectural features of schizophrenia which are often discussed, notably entorhinal cortex heterotopias and hippocampal neuronal disarray, remain to be confirmed. The phenotype of the affected neuronal and synaptic populations is uncertain. A case can be made for impairment of hippocampal and corticocortical excitatory pathways, but in general the relationship between neurochemical findings (which centre upon dopamine, 5-hydroxytryptamine, glutamate and GABA systems) and the neuropathology of schizophrenia is unclear. Gliosis is not an intrinsic feature; its absence supports, but does not prove, the prevailing hypothesis that schizophrenia is a disorder of prenatal neurodevelopment. The cognitive impairment which frequently accompanies schizophrenia is not due to Alzheimer's disease or any other recognized neurodegenerative disorder. Its basis is unknown. Functional imaging data indicate that the pathophysiology of schizophrenia reflects aberrant activity in, and integration of, the components of distributed circuits involving the prefrontal cortex, hippocampus and certain subcortical structures. It is hypothesized that the neuropathological features represent the anatomical substrate of these functional abnormalities in neural connectivity. Investigation of this proposal is a goal of current neuropathological studies, which must also seek (i) to establish which of the recent histological findings are robust and cardinal, and (ii) to define the relationship of the pathological phenotype with the clinical syndrome, its neurochemistry and its pathogenesis.
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Affiliation(s)
- P J Harrison
- University Department of Psychiatry, Warneford Hospital, Oxford, UK.
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