Complement system and circulating immune complexes under schizophrenia: Family study

64

5. Neuropathology, Biochemistry

observed. This is the first study that confirmed the region selectivity and the ligand selectivity of the reduction of the 5-HT2A receptors in the subjects with schizophrenia by examining multiple brain regions from age- and sex-matched pairs. These findings support a possible involvement of a serotonergic system in the dorsolateral prefrontal cortex in the pathology of schizophrenia.

MOLECULAR

ABNORMALITIES

OF THE

HIPPOCAMPUS

IN SEVERE MENTAL ILLNESS:

POST-MORTEM

FINDINGS FROM THE

STANLEY NEUROPATHOLOGY

CONSORTIUM

M. B. Knable,* B. B. Bm'ci, J. J. Bartko, M. J. Webster, E. E Torrey Stanley Medical Research Institute, Bethesda, MD, USA Between 1994 and 2002, 48 data sets were returned from anterior hippocampal speciments from the Stanley Neuropathology Consortium. Data sets referable to the dentate gyms, CA1-CA4, and the subiculum, that contained at least 90% complete data, were selected for meta-analysis. When data for hippocampal subdivisions were counted separately, 224 variables were available for analysis. Missing data were imputed with a "hot-deck" procedure. The majority of data sets were not normally distributed. The entire set of markers was therefore tested with individual Kruskal-Wallis H tests. A DunnSidak correction for multiple comparisons was applied to the results. The data sets were also analyzed using the non-parametric classification and regression tree (CART) method. Two of the 224 variables revealed a significant difference between groups. The total number and density of parvalbumin labeled neurons in CA2 were decreased in schizophrenia samples(p<0.00t) relative to controls. The total number of parvalbumin labeled neurons was decreased in bipolar samples (p<0.04) relative to controls. Immuno-positive neurons for reelin were decreased in the molecular layer of the dentate gyms in schizophrenia (p=0.0002), bipolar disorder (p=0.004) and in depression (p=0.04). CART analysis with all four diagnostic groups revealed a maximum cmxet classification of 38% (p=0.016) with immuno-positive neurons for reelin in CA4 and immuno-positive neurons for SNAP-25 in the stratum oriens. Pair-wise CART analyses revealed significant maximal classifications between bipolar disorder and depression with SNAP-25 in stratum oriens, between bipolar disorder and schizophrenia with SNAP-25 in stratum oriens, and between bipolar disorder and normal controls with TrkA RNA in CA2 (p values <0.02). Depression was discriminated from normal controls by immuno-labeled neurons for reelin in CA4. The implications of these findings for the molecular neuropathology of severe mental illness will be discussed.

LOW GLYCOGEN

SYNTHASE

SCHIZOPHRENIA

- GENETIC MARKER

CONSEQUENCE

KINASE-3~ IN OR

OF NEURODEVELOPMENTAL

INSULT N. Kozlovsky,* C. Nadri, B. K. Lipska, D. R. Weinberger, C. Shannon-Weickert, J. E. Kleinman, R. H. Belmaker, G. A g a m Stanley Foundation Research Center, Ben-Gurion University, BeerSheva, Israel Glycogen synthase kinase-3 (GSK-3) is a protein kinase highly abundant in brain and involved in signal transduction cascades, particu-

larty neurodevelopment. Its activity and protein levels have recently been reported to be over 40% lower in postmortem frontal cortex of schizophrenic patients. GSK-3~3 in occipital cortex of schizophrenic patients was not reduced, suggesting regional specificity. There was no reduction in GSK-3~3 mRNA, protein levels or activity in fl:esh lymphocytes from schizophrenic patients. In the schizophrenia-related neonatal ventral hippocainpal lesion rat model we measured GSK3[3 protein levels and GSK-3 activity in the frontal cortex. GSK3~levels in lesioned rats were significantly lower than in sham rats, favoring perinatal insult as a cause of low GSK-3~3in schizophrenia. Taken together, these studies suggest that low GSK-3 in postmortembrain of schizophrenic patients is a late consequence of neurodevelopmental insult in schizophrenia and not a genetic marker of schizophrenia. In rats, acute or chronic cold restraint stress did not change GSK-3[~ protein levels, although functional GSK-3 activation is involved in the cellular stress response. Chronic treatment of rats with lithium, valproate, haloperidol or clozapine did not change rat cortical GSK-3~3 protein levels ex vivo, supporting the concept that low GSK-3[3 in schizophrenia is not secondary to stress or drug treatment. Our initial findings of low GSK-3[3 protein levels in postmortembrain have been replicated by another group. Our own group has found additionally that GSK-3[~ mRNA levels were 40% lower in postmortem DLPFC of schizophrenic patients, supporting ore"previous findings. An additional intriguing recent preliminary finding is that GSK-3[3 protein levels in CSF samples from schizophrenic patients are 28% lower than in control subjects. Further studies will be aimed at determining whether nonspecific neonatal damage or only specific factors cause low GSK-3 as a late effect. We plan to study whether low GSK-3[3 activity is associated with biochemical effects such as elevatedb~-catenin levels.

COMPLEMENT IMMUNE

SYSTEM AND CIRCULATING

COMPLEXES

SCHIZOPHRENIA:

UNDER

FAMILY STUDY

K. Mayilyan,* A. Boyajyan, S. Hakopyan, A. Soghoyan, R. B. Sire Institute of Molecular Biology of Al~nenian National Academy of. Sciences, Yerevan, Armenia The examination of families with positive history of schizophrenia is important for understanding the molecular pathomechanisms of this disorder. Using the blood samples of healthy volunteers (n=77), healthy and affected members (n=83) from three generations of twenty one families with positive history of schizophrenia we have tested classical pathway total complement (TCH) and C4 component haemolytic activities (CH50) and concentration of circulating immune complexes (CICs), as well as identified the protein components of these complexes by the use of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE). The percentage ratio of pathogenic CICs has been determined by using appropriate plotting method. Investigation of TCH activity did not reveal any significant difference between groups, whereas C4 component haemolytic activity of subjects with positive history of schizophrenia was sufficiently up regulate. In serum of schizophrenia affected members the mean concentration of small CICs was within a normal range, while concentration of gigantic, big and middle CICs were, correspondingly, 1.6, 1.8 and 1.9 times higher than data of controls (p<0.0001). It has been shown that 83.3% of immune complexes circulating in the blood of examined schizophrenic patients had pathogenic features. However, there were not difference between obtained data of schizophrenia-affected members and their healthy relatives. The SDS PAGE of C1Cs isolated from the blood of two big families'

International Congress on Schizophrenia Research 2003

5. Neuropathology, Biochemistry

65

members revealed the presence of a single polypeptide chain with the apparent molecular weights of 51000 and absent from the CICs of the healthy volunteers' group. The research was supported by INTAS Fellowship Grant for Young Scientists (N -YSF 2001/2-0110).

EXPRESSION OF VESICULAR GLUTAMATE TRANSPORTERS ONE AND TWO IN MEDIAL TEMPORAL LOBE STRUCTURES IN SCHIZOPHRENIA, BIPOLAR DISORDER, AND MAJOR DEPRESSIVE DISORDER R. E. M c C u l l u m s m i t h , * J. H. M e a d o r - W o o d r u f f

Mental Health Research Institute and Department of Psychiatry, University o[Michigan, Ann Arbog MI, USA Abnormalities ofionotropic glutamate receptor expression have been reported in various brain regions of schizophrenic subjects. While these data are consistent with a hypothesis of altered glutamatergic activity in schizophrenia, other components of the glutamate synapse warrant closer scrutiny, since glutamate receptors are only one of multiple classes of molecules essential for normal ghitamatergic neurotransmission. One family of candidate genes includes the recently identified vesicular glutamate transporters (vGluts). The brainspecific Na+ -dependent inorganic phosphate transporter (BNPi) was shown to transport glutamate into synaptic vesicles targeted for stimulus-specific exocytosis. Originally characterized as a plasma membrane inorganic phosphate transporter, BNPi (vGlut 1) is localized to the membranes of small synaptic vesicles in terminals forlning asymmetric excitatory-type synapses. Two other members of the vGlut family, DNPi (differentiation-associated Na+/Pi cotransporter)(vGlut2) and vGlut3, also transport glutamate into synaptic vesicles and share significant sequence homology with BNPi. Expression of these presynaptic molecules essential for norreal glutamatergic neurotransmission has not been characterized in medial temporal lobe structures in schizophrenia and other psychiatric illnesses. Thus, we investigated hippocampal expression of the transcripts encoding the vesicular glutamate transporters vGlutl-2 in subjects with schizophrenia, bipolar disorder (BD), or major depressive disorder (MDD). We have designed and synthesized specific probes for the vGLUTI-2 genes for in situ hybridization using tissue from the Stanley Foundation Neuropathology Consortium. We did not detect changes in vGlut 1 transcript expression in the dentate gyms, subicuhim, CA1, CA2, or CA3 in schizophrenia, BD, or MDD. vGhit2 expression was not detected in these regions. Analysis of vGlut 1-2 mRNA expression in the entorhinal cortex and medial and inferior temporal neocortex will be presented. Our results suggest that expression of presynaptic molecules such as vGlutl are not altered in schizophrenia, despite previous studies demonstrating changes in ionotropic glutamate receptor and plasma membrane glutamate transporter expression in the HPC.

EXPRESSION OF THE NR3A SUBUNIT OF THE NMDA RECEPTOR IN HUMAN BRAIN H. T. Mueller,* J. H. M e a d o r - W o o d r u f f

Neuroscience, University of Michigan, Ann Arbor, MI, USA NMDA receptors (NMDARs) play an important role in many normal and pathological processes in the brain. NMDARs are ligand-gated ion channels comprised of heteromeric assemblies of subunits encoded by 7 different genes, NR1, NR2 (A-D) and NR3A and NR3B. Changes in subunit composition can alter pharmacological and phys-

iological properties of the NMDAR, suggesting differential expression of these various subunits may be important for regulating NMDAR function. Pharmacological evidence implicates decreased NMDAR function in schizophrenia. In support of this, alterations in NMDAR subunit expression have been found in schizophrenia. The NR3A subunit has not been investigated in humans, but electrophysiological studies suggest that the NR3A subunit can decrease NMDAR current. The ability of the NR3A subunit to modulate NMDAR activity suggests it may play a role in NMDAR dysfunction in schizophrenia. In addition, there is emerging evidence that there is a neurodevelopmental component involved in the pathophysiology of schizophrenia. The second trimester appears to be a particularily critical time in brain development that is vulnerable for the phenotypic expression of schizophrenia. Interstingly, the NR3A subunit also displays unique developmental and anatomical distributions in the rat brain that further suggest the NR3A subunit may play a role in schizophrenia. Therefore we sought to examine NR3A mRNA expression in human fetal and adult brain by in situ hybridization to test the hypotheses that the NR3A subunit is developmentally expressed in the human and is altered in schizophrenia. Our results indicate that the NR3A subunit is expressed at high levels during human brain development, peaking during the second trimester. Further, its expression is most abundant in regions often implicated in schizophrenia, such as limbic cortex and associated brain regions. While NR3A expression decreases with time, its expression persists in the adult in these same brain regions at detectable levels. We have preliminary data indicating NR3A expression is decreased in temporal neocortcx in schizophrenia. Taken together, our data suggest the NR3A subunit is highly expressed during human brain development and may be altered in schizophrenia.

DOPAMINE RECEPTOR TRANSCRIPT ABNORMALITIES IN THE DORSOLATERAL PREFRONTAL CORTEX IN SCHIZOPHRENIA, BIPOLAR DISORDER, AND MAJOR DEPRESSIVE DISORDER S. A. Oakman,* J. H. Meador-Woodruff Psychiatry, University ()f Michigan, Ann Arbo~ MI, USA Altered dopaminergic neurotransmission in the dorsolateraI prefrontal cortex, particularly at Dl-type receptors, has been implicated in the working memory deficits observed in schizophrenia. This area may also be involved in cognitive and emotional processes in mood disorders, as well as in their responses to antidepressant treatment and transcranial magnetic stimulation. Studies of other regions of prefrontal cortex, namely orbitofrontal cortex, have demonstrated decreases in expression of D3 and D4 receptor transcripts. To date, however, no study of dopmnine receptor transcripts in human dorsolateral prefrontal cortex has been reported. We investigated expression of dopamine receptor transcripts in the dorsolateral prefrontal cortex of patients with schizophrenia, major depression, and bipolar disorder. In situ hybridization with probes specifically designed for human D1, D2, D3, D4, and D5 receptor transcripts was performed on tissue obtained from the Stanley Foundation Neuropathology Consortium. Transcripts of all five receptor types were detected in dorsolateral prefrontal cortex in patients and controls. No quantitative differences were seen in expression o f D l , D3, or D4 transcripts in this area when comparing patient groups to unaffected controls. D2 receptor expression was significantly decreased in cortex fi'om schizophrenic and depressed patients, but not in bipolar disorder. There

International Congress on Schizophrenia Research 2003