Frontal Cortex Of Patients Research Articles

Transcriptional modulator H2A histone family, member Y ( H2AFY ) marks Huntington disease activity in man and mouse

Huntington disease (HD) is a progressive neurodegenerative disease that affects 30,000 individuals in North America. Treatments that slow its relentless course are not yet available, and biomarkers that can reliably measure disease activity and therapeutic response are urgently needed to facilitate their development. Here, we interrogated 119 human blood samples for transcripts associated with HD. We found that the dynamic regulator of chromatin plasticity H2A histone family, member Y (H2AFY) is specifically overexpressed in the blood and frontal cortex of patients with HD compared with controls. This association precedes the onset of clinical symptoms, was confirmed in two mouse models, and was independently replicated in cross-sectional and longitudinal clinical studies comprising 142 participants. A histone deacetylase inhibitor that suppresses neurodegeneration in animal models reduces H2AFY levels in a randomized phase II clinical trial. This study identifies the chromatin regulator H2AFY as a potential biomarker associated with disease activity and pharmacodynamic response that may become useful for enabling disease-modifying therapeutics for HD.

Up-regulation of major vault protein in the frontal cortex of patients with intractable frontal lobe epilepsy

Major vault protein (MVP) is a vesicular drug transporter and may participate in multidrug resistance (MDR). The aim of this study was to determine the expression and cellular localization of MVP in refractory frontal lobe epilepsy (FLE). We detected MVP expression in tissue samples from the refractory frontal cortex of 30 patients who had been surgically treated for refractory epilepsy. We compared these tissues with twelve histologically normal frontal lobe samples from controls. In the control group, the expression of MVP was faint in the cortex. The expression of MVP protein increased dramatically in the refractory epilepsy group; MVP immunoreactivity (IR) was observed in the cytoplasm of neurons. Thus, MVP protein was increased in the frontal cortex of patients with refractory epilepsy. Further research is necessary to determine whether or not MVP plays a role in the mechanisms underlying drug resistance in refractory FLE.

Impaired mitochondrial dynamics and abnormal interaction of amyloid beta with mitochondrial protein Drp1 in neurons from patients with Alzheimer's disease: implications for neuronal damage.

The purpose of our study was to better understand the relationship between mitochondrial structural proteins, particularly dynamin-related protein 1 (Drp1) and amyloid beta (Aβ) in the progression of Alzheimer's disease (AD). Using qRT-PCR and immunoblotting analyses, we measured mRNA and protein levels of mitochondrial structural genes in the frontal cortex of patients with early, definite and severe AD and in control subjects. We also characterized monomeric and oligomeric forms of Aβ in these patients. Using immunoprecipitation/immunoblotting analysis, we investigated the interaction between Aβ and Drp1. Using immunofluorescence analysis, we determined the localization of Drp1 and intraneuronal and oligomeric Aβ in the AD brains and primary hippocampal neurons from Aβ precursor protein (AβPP) transgenic mice. We found increased expression of the mitochondrial fission genes Drp1 and Fis1 (fission 1) and decreased expression of the mitochondrial fusion genes Mfn1 (mitofusin 1), Mfn2 (mitofusin 2), Opa1 (optic atrophy 1) and Tomm40. The matrix gene CypD was up-regulated in AD patients. Results from our qRT-PCR and immunoblotting analyses suggest that abnormal mitochondrial dynamics increase as AD progresses. Immunofluorescence analysis of the Drp1 antibody and the Aβ antibodies 6E10 and A11 revealed the colocalization of Drp1 and Aβ. Drp1 immunoprecipitation/immunoblotting analysis of Aβ antibodies 6E10 and A11 revealed that Drp1 interacts with Aβ monomers and oligomers in AD patients, and these abnormal interactions are increased with disease progression. Primary neurons that were found with accumulated oligomeric Aβ had lost branches and were degenerated, indicating that oligomeric Aβ may cause neuronal degeneration. These findings suggest that in patients with AD, increased production of Aβ and the interaction of Aβ with Drp1 are crucial factors in mitochondrial fragmentation, abnormal mitochondrial dynamics and synaptic damage. Inhibiting, these abnormal interactions may be a therapeutic strategy to reduce mitochondrial fragmentation, neuronal and synaptic damage and cognitive decline in patients with AD.

Increased CDK5 Expression in HIV Encephalitis Contributes to Neurodegeneration via Tau Phosphorylation and Is Reversed with Roscovitine

Recent treatments with highly active antiretroviral therapy (HAART) regimens have been shown to improve general clinical status in patients with human immunodeficiency virus (HIV) infection; however, the prevalence of cognitive alterations and neurodegeneration has remained the same or has increased. These deficits are more pronounced in the subset of HIV patients with the inflammatory condition known as HIV encephalitis (HIVE). Activation of signaling pathways such as GSK3β and CDK5 has been implicated in the mechanisms of HIV neurotoxicity; however, the downstream mediators of these effects are unclear. The present study investigated the involvement of CDK5 and tau phosphorylation in the mechanisms of neurodegeneration in HIVE. In the frontal cortex of patients with HIVE, increased levels of CDK5 and p35 expression were associated with abnormal tau phosphorylation. Similarly, transgenic mice engineered to express the HIV protein gp120 exhibited increased brain levels of CDK5 and p35, alterations in tau phosphorylation, and dendritic degeneration. In contrast, genetic knockdown of CDK5 or treatment with the CDK5 inhibitor roscovitine improved behavioral performance in the water maze test and reduced neurodegeneration, abnormal tau phosphorylation, and astrogliosis in gp120 transgenic mice. These findings indicate that abnormal CDK5 activation contributes to the neurodegenerative process in HIVE via abnormal tau phosphorylation; thus, reducing CDK5 might ameliorate the cognitive impairments associated with HIVE.

Structural and functional neuroimaging studies of the suicidal brain

Suicidality is a major challenge for today's health care. Evidence suggests that there are differences in cognitive functioning of suicidal patients but the knowledge about the underlying neurobiology is limited. Brain imaging offers the advantage of a non-invasive in vivo direct estimation of detailed brain structure, regional brain functioning and estimation of molecular processes in the brain. We have reviewed the literature on neuroimaging studies of the suicidal brain. This article contains studies on structural imaging such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) and functional imaging, consisting of Positron Emission Tomography (PET), Single Photon Emission Tomography (SPECT) and functional MRI (fMRI). We classified the results of the different imaging modalities in structural and functional imaging. Within our research, we found no significant differences in the suicidal brain demonstrated by Computed Tomography. Magnetic Resonance Imaging studies in subjects with a history of suicide attempt on the other hand deliver differing results, mostly pointing at a higher prevalence of white (especially deep white matter and periventricular) and grey matter hyperintensities in the frontal, temporal and/or parietal lobe and decreased volumes in the frontal and temporal lobe. There seems to be a trend towards findings of reduced grey matter volume in the frontal lobe. Overall, there is no consensus of opinion on structural imaging of the suicidal brain. Research on functional imaging is further divided into studies in resting state, studies in activation conditions and studies on brain neurotransmitters, transporters and receptors. A common finding in functional neuroimaging in resting conditions is a decreased perfusion in the prefrontal cortex of suicidal patients. During cognitive activation, perfusion deficits in the prefrontal cortex have been observed. After fenfluramine challenge, the prefrontal cortex metabolism seems to be inversely correlated to the lethality of previous suicide attempt. The few studies that examined the serotonin transporter in suicide found no significant differences in binding potential. In suicide attempters there seems to be a negative correlation between impulsivity and SERT binding. Our group found a reduced 5-HT(2A) binding in the frontal cortex in patients with a recent suicide attempt. The binding index was significantly lower in the deliberate self injury patients compared to the deliberate self poisoning patients. The few authors that examined DAT binding in suicide found no significant DAT differences between patients and controls. However they demonstrated significant negative correlations between DAT binding potential and mental energy among suicide attempters, but not in healthy control subjects. We did not find studies measuring the binding potential of the noradrenalin or gamma amino butyric acid transporter or receptor in suicidal subjects. Several reports have suggested abnormalities of GABA neurotransmission in depression. During our literature search, we have focused on neuroimaging studies in suicidal populations, but in the absence of evidence in the literature on this group or when further collateral evidence is appropriate, this overview expands to results in impulsive aggressive or in depressed subjects.

Altered enzymatic activity and allele frequency of OMI/HTRA2 in Alzheimer's disease

The serine-protease OMI/HTRA2, required for several cellular processes, including mitochondrial function, autophagy, chaperone activity, and apoptosis, has been implicated in the pathogenesis of both Alzheimer's disease (AD) and Parkinson's disease (PD). Western blot quantification of OMI/HTRA2 in frontal cortex of patients with AD (n=10) and control subjects (n=10) in two separate materials indicated reduced processed (active, 35 kDa) OMI/HTRA2 levels, whereas unprocessed (50 kDa) enzyme levels were not significantly different between the groups. Interestingly, the specific protease activity of OMI/HTRA2 was found to be significantly increased in patients with AD (n=10) compared to matched control subjects (n=10) in frontal cortex in two separate materials. Comparison of OMI/HTRA2 mRNA levels in frontal cortex and hippocampus, two brain areas particularly affected by AD, indicated similar levels in patients with AD (n=10) and matched control subjects (n=10). In addition, we analyzed the occurrence of the OMI/HTRA2 variants A141S and G399S in Swedish case-control materials for AD and PD and found a weak association of A141S with AD, but not with PD. In conclusion, our genetic, histological, and biochemical findings give further support to an involvement of OMI/HTRA2 in the pathology of AD; however, further studies are needed to clarify the role of this gene in neurodegeneration.

Increased expression of urokinase‐type plasminogen activator receptor in the frontal cortex of patients with intractable frontal lobe epilepsy

Urokinase-type plasminogen activator receptor (uPAR) is a glycosyl phosphatidylinositol-anchored protein involved in cell adhesion, proliferation, differentiation, migration, invasion, and tissue repair and remodeling. Our aim was to investigate uPAR expression in the frontal cortex of patients with intractable frontal lobe epilepsy and to explore the possible role of uPAR in intractable epilepsy. Tissue samples were obtained from the frontal cortex of 25 patients who had undergone surgery for intractable epilepsy and 15 histologically normal frontal cortex tissues from patients with orbital frontal lobe severe contusion (the control group). The frontal cortex expression of uPAR was studied by Western blot and immnohistochemistry. Double immunofluorescence was used to determine the expression of uPAR in astrocytes, microglia, and neurons. The normal frontal cortex uPAR protein level was shown to be low. In the brain tissue of patients with intractable epilepsy, the expression of uPAR protein increased dramatically. Based on the results of double immunofluorescence, many uPAR-positive cells are colocalized with the cell soma of NeuN-positive neurons, whereas only a few GFAP- and CD11b-positive cells colocalized with uPAR staining. These findings provide new information pertaining to the epileptogenesis of intractable epilepsy and suggest that increased expression of uPAR in human brain may be associated with human intractable epilepsy.

Involvement of peptidylarginine deiminase-mediated post-translational citrullination in pathogenesis of sporadic Creutzfeldt-Jakob disease

Peptidylarginine deiminases (PADs)-mediated post-translational citrullination processes play key roles in protein functions and structural stability through the conversion of arginine to citrulline in the presence of excessive calcium concentrations. In brain, PAD2 is abundantly expressed and can be involved in citrullination in disease. Recently, we have reported pathological characterization of PAD2 and citrullinated proteins in scrapie-infected mice, but the implication of protein citrullination in the pathophysiology in human prion disease is not clear. In the present study, we explored the molecular and biological involvement of PAD2 and the pathogenesis of citrullinated proteins in frontal cortex of patients with sporadic Creutzfeldt-Jakob disease (sCJD). We found increased expression of PAD2 in reactive astrocytes that also contained increased levels of citrullinated proteins. In addition, PAD activity was significantly elevated in patients with sCJD compared to controls. From two-dimensional gel electrophoresis and MALDI-TOF mass analysis, we found various citrullinated candidates, including cytoskeletal and energy metabolism-associated proteins such as vimentin, glial fibrillary acidic protein, enolase, and phosphoglycerate kinase. Based on these findings, our investigations suggest that PAD2 activation and aberrant citrullinated proteins could play a role in pathogenesis and have value as a marker for the postmortem classification of neurodegenerative diseases.

Fibromyalgia unique temporal brain activation during experimental pain: a controlled fMRI Study

Studies with functional neuroimaging support the hypothesis of central pain augmentation in fibromyalgia syndrome (FMS) with functional differences in areas of the medial pain system. To clarify whether these findings are unique to patients with FMS, BOLD-signal patterns during and before tonic experimental pain were compared to healthy controls and patients with rheumatoid arthritis (RA) as a chronic pain disorder of somatic origin. We expected different BOLD-signal patterns in areas of the medial pain system that were most pronounced in patients with FMS. An fMRI-block design before, during and after an incision was performed in patients with FMS (n = 17), RA (n = 16) and in healthy controls (n = 17). A 2-factorial model of BOLD-signal changes was designed to explore significant differences of brain activation between the groups during the pain stimulus. Additionally, the correlation of brain activity during the anticipation of pain with the amount of the impending pain was determined. We observed a FMS-unique temporal brain activation of the frontal cortex in patients with FMS. Moreover, areas of the motor cortex and the cingulate cortex presented a FMS-specific relation between brain activity during pain anticipation and the magnitude of the subsequent pain experience. Our results support the hypothesis that central mechanisms of pain processing in the frontal cortex and cingulate cortex may play an important role in patients with FMS.

Loss of astrocytic glutamate transporters in Wernicke encephalopathy.

Wernicke encephalopathy (WE), a neurological disorder caused by thiamine deficiency (TD), is characterized by structural damage in brain regions that include the thalamus and cerebral cortex. The basis for these lesions is unclear, but may involve a disturbance of glutamatergic neurotransmission. We have therefore investigated levels of the astrocytic glutamate transporters EAAT1 and EAAT2 in order to evaluate their role in the pathophysiology of this disorder. Histological assessment of the frontal cortex revealed a significant loss of neurons in neuropathologically confirmed cases of WE compared with age-matched controls, concomitant with decreases in alpha-internexin and synaptophysin protein content of 67 and 52% by immunoblotting. EAAT2 levels were diminished by 71% in WE, with levels of EAAT1 also reduced by 62%. Loss of both transporter sites was confirmed by immunohistochemical methods. Development of TD in rats caused a profound loss of EAAT1 and EAAT2 in the thalamus accompanied by decreases in other astrocyte-specific proteins. Treatment of TD rats with N-acetylcysteine prevented the downregulation of EAAT2 in the medial thalamus, and ameliorated the loss of several other astrocyte proteins, concomitant with increased neuronal survival. Our results suggest that (1) loss of EAAT1 and EAAT2 glutamate transporters is associated with structural damage to the frontal cortex in patients with WE, (2) oxidative stress plays an important role in this process, and (3) TD has a profound effect on the functional integrity of astrocytes. Based on these findings, we recommend that early treatment using a combination of thiamine AND antioxidant approaches should be an important consideration in cases of WE.

Differential damage in the frontal cortex with aging, sporadic and familial Alzheimer's disease

In order to understand relationships between executive and structural deficits in the frontal cortex of patients within normal aging or Alzheimer's disease, we studied frontal pathological changes in young and old controls compared to cases with sporadic (AD) or familial Alzheimer's disease (FAD). We performed a semi-automatic computer assisted analysis of the distribution of β-amyloid (Aβ) deposits revealed by Aβ immunostaining as well as of neurofibrillary tangles (NFT) revealed by Gallyas silver staining in Brodman areas 10 (frontal polar), 12 (ventro-infero-median) and 24 (anterior cingular), using tissue samples from 5 FAD, 6 sporadic AD and 10 control brains. We also performed densitometric measurements of glial fibrillary acidic protein, principal compound of intermediate filaments of astrocytes, and of phosphorylated neurofilament H and M epitopes in areas 10 and 24. All regions studied seem almost completely spared in normal old controls, with only the oldest ones exhibiting a weak percentage of β-amyloid deposit and hardly any NFT. On the contrary, all AD and FAD cases were severely damaged as shown by statistically significant increased percentages of β-amyloid deposit, as well as by a high number of NFT. FAD cases (all from the same family) had statistically more β-amyloid and GFAP than sporadic AD cases in both areas 10 and 24 and statistically more NFT only in area 24. The correlation between the percentage of β-amyloid and the number of NFT was significant only for area 24. Altogether, these data suggest that the frontal cortex can be spared by AD type lesions in normal aging, but is severely damaged in sporadic and still more in familial Alzheimer's disease. The frontal regions appear to be differentially vulnerable, with area 12 having the less amyloid burden, area 24 the less NFT and area 10 having both more amyloid and more NFT. This pattern of damage in frontal regions may represent a strong neuroanatomical support for the deterioration of attention and cognitive capacities as well as for the presence of emotional and behavioral troubles in AD patients.

Cholinergic denervation occurs early in Parkinson disease

Although Parkinson disease (PD) is viewed traditionally as a motor syndrome secondary to nigrostriatal dopaminergic denervation, recent studies emphasize nonmotor features. Nonmotor comorbidity, such as cognitive impairment, can be explained better by multisystem neurodegeneration that extends beyond the loss of dopaminergic nigral neurons.1 Lewy2 first identified the eponymous Lewy body in neurons of the nucleus basalis of Meynert, the source of cholinergic innervation of the cerebral cortex. There is considerable evidence for altered cholinergic neurotransmission in PD. In the Braak et al.3 staging scheme of PD pathology, nigral and basal forebrain pathology occur simultaneously. Loss of cholinergic forebrain neurons in PD postmortem specimens is of similar magnitude or greater than loss found in Alzheimer disease (AD).4 A postmortem study found greater reductions of acetylcholinesterase (AChE) in the frontal cortex of patients with dementia compared to patients without dementia with PD.5 The development of PET technology to measure AChE functional activity offers the opportunity to study cholinergic innervation in vivo at early stages of neurodegenerative disorders. In this issue of Neurology ®, …

Decreased glutamic acid decarboxylase 67 mRNA expression in multiple brain areas of patients with schizophrenia and mood disorders

Reduced levels of glutamic acid decarboxylase 67 (GAD 67), an essential enzyme for GABA synthesis, is one of the most consistent gene expression changes found in the frontal cortex of patients with schizophrenia. Recently this reduction has been shown to extend to other areas including primary sensory, primary motor and anterior cingulate (ACC) cortices. To determine the extent to which additional cortical and subcortical regions may be affected in schizophrenia, we measured the level of GAD 67 mRNA in previously unexplored areas including the orbitofrontal (OFC) and superior temporal (STG) cortices as well as the caudate, putamen, nucleus accumbens, medial dorsal thalamus and anterior thalamus using in situ hybridization. We also examined GAD 67 mRNA levels in all these regions in individuals with bipolar disorder and major depression. ANCOVA comparing GAD 67 mRNA levels in all four diagnostic groups revealed a significant reduction (∼30%) in layers III and IV of the OFC of patients with schizophrenia and bipolar disorder. A priori t-tests comparing GAD 67 mRNA levels between the schizophrenia and control groups revealed significant reductions in the ACC, STG, striatum and thalamus. These findings suggest that there may be a widespread reduction in GABA neurotransmission due to a decrease in the synthesis of GAD 67 in subjects with psychiatric disorders. The resulting decrease in inhibitory tone across multiple brain areas may contribute to the psychotic behavior observed in patients with schizophrenia and bipolar disorder.

Morphometric study of the frontal cortex in subacute sclerosing panencephalitis.

In biopsic material collected from the frontal cortex of 6 patients with subacute sclerosing panencephalitis (SSPE) and 5 patients with posterior fossa tumors, we estimated the neuronal and synaptic numerical densities as well as the mean volume of the neurons from layers II and III. The thickness of these layers was also determined. The evaluation of the layer's thickness suggested that there was no difference in the shrinkage in SSPE as compared to controls. No differences were found between the neuronal numerical densities and the neuronal soma sizes from SSPE and controls. Conversely the synaptic numerical density was reduced in SSPE. Given the maintenance of the neuronal numerical density in the frontal cortex of patients with SSPE, the presence of a decreased density of synapses must be regarded as a consequence of the dendritic and axonal degeneration that we previously described in this condition. It must then be borne in mind that SSPE's functional and behavioral changes might spring from alterations of the frontal cortex neuronal circuitry.

Impaired frontal synchronization of spontaneous magnetoencephalographic activity in patients with bipolar disorder

Recent functional imaging studies demonstrated that brain exhibit coherent, synchronized activities during resting state and the dynamics may be impaired in various psychiatric illnesses. In order to investigate the change of neural dynamics in bipolar disorder, we used a new nonlinear measurement “similarity index” to analyze the magnetoencephalography (MEG) recordings and test the hypothesis that there are synchronization changes within different frequency bands in the frontal cortex of patients with bipolar disorder. Ten patients with bipolar I disorder during euthymic phase and ten normal controls underwent 2 min eye-closed resting recording with a whole-head 306-channel MEG system. Eleven channels of MEG data from frontal area were selected for analysis. Synchronization level in the delta (2–4 Hz), theta (4–8 Hz), alpha (8–12 Hz) and beta (12–24 Hz) bands was calculated for each subject and compared across group. The results showed that significant dynamic changes in bipolar patients can be characterized by increased synchronization of slow frequency oscillations (delta) and decreased synchronization of fast frequency oscillations (beta). Furthermore, the positive correlation between beta synchronization level and preservative errors in Wisconcin card sorting task was found which would implicate the deficit of executive function in bipolar patients. Our findings indicate that analysis of spontaneous MEG recordings at resting state using nonlinear dynamic approaches may disclose the subtle regional changes of neural dynamics in BD.

Levels of Estrogen Receptors α and β in Frontal Cortex of Patients with Alzheimers Disease: Relationship to Mini-Mental State Examination Scores

Estrogen exerts beneficial effects on the brain throughout life. Studies demonstrate that estrogen is neuroprotective and that reduced brain estrogen activity may influence the clinical course of Alzheimer's disease (AD). Changes in levels of estrogen receptors have been detected in postmortem brain tissue of AD patients. Very little is known about the relationship between clinical stage and levels of estrogen receptors in postmortem brain. We hypothesized that estrogen receptor levels would be related to severity of cognitive impairment assessed proximate to death. Western blotting was used to quantify ER-alpha and ER-beta in nuclear, cytosolic, and crude membrane fractions of superior frontal cortex from 25 AD patients. Multiple linear regression analyses adjusted for age, sex, and education showed a significant linear relationship between Mini-Mental State Examination score (MMSE) and wild-type nuclear ER-alpha (â = 5.463, p = 0.03), but none between MMSE and wild-type nuclear ER-beta (â = 2.29, p = 0.36). We incidentally observed additional higher and lower molecular mass bands for ER-alpha in study subjects. Additional experiments performed on frontal cortex nuclear fractions prepared from subjects enrolled in a different study confirmed that these same bands are present in female and males with and without AD. Together our data show a relationship between wild-type ER-alpha and level of cognitive impairment in AD, and also suggest the possibility that variant isoforms of ER-alpha may be present in frontal cortex of patients with and without AD.

Parkin and synphilin-1 isoform expression changes in Lewy body diseases

Alternative splicing gives rise to at least seven parkin and eight synphilin-1 isoforms. Since both parkin and synphilin-1 have been involved in Lewy body (LB) formation, we decided to explore whether their isoforms are differentially expressed in LB diseases. With this aim, we studied relative mRNA expression levels of parkin and synphilin-1 isoforms in the frontal cortices of patients with dementia with LBs, the LB variant of Alzheimer's disease and Parkinson's disease and compared the findings with those obtained from Alzheimer's disease patients and control individuals. Duplex real-time PCR reactions, with beta-actin as internal standard, were carried out in a LightCycler. mRNA expression levels of parkin and synphilin-1 isoforms were seen to be specifically altered in each of the LB diseases studied. These findings suggest that parkin and synphilin-1 isoform expression changes play a significant role in the pathogenesis of LB diseases.

Evidence for oxidative stress in the frontal cortex in patients with recurrent depressive disorder—a postmortem study

Prefrontal cortical (PFC) and hippocampal (HI) volume reductions have been consistently found in patients with recurrent depressive disorder (DD). Here we examine the possibility that oxidative stress, widely implicated in neuronal cell damage, may contribute to these brain structural changes. We compared manganese (Mn) and copper/zinc (Cu/Zn) superoxide dismutase (SOD) coenzyme concentrations in postmortem PFC and hippocampal brain tissue from 7 patients with DD and 7 neuropsychiatrically healthy controls using sandwich-type enzyme-linked immunosorbent assay (ELISA) technique. The concentration of Cu/Zn-SOD was significantly increased in the PFC but not in the hippocampus of patients. There was no significant change in Mn-SOD enzyme concentration in either region. Our findings contribute to the growing body of evidence implicating oxidative stress in the pathophysiology of depressive disorder.

Proteomic identification of novel proteins in cortical lewy bodies.

Lewy body (LB) inclusions are one of the pathological hallmarks of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). One way to better understand the process leading to LB formation and associated pathogenesis responsible for neurodegeneration in PD and DLB is to examine the content of LB inclusions. Here, we performed a proteomic investigation of cortical LBs, obtained by laser capture microdissection from neurons in the temporal cortex of dementia patients with cortical LB disease. Analysis of over 2500 cortical LBs discovered 296 proteins; of those, 17 had been associated previously with brainstem and/or cortical LBs. We validated several proteins with immunohistochemical staining followed by confocal microscopy. The results demonstrated that heat shock cognate 71 kDa protein (also known as HSC70, HSP73, or HSPA10) was indeed not only colocalized with the majority of LBs in the temporal cortex but also colocalized to LBs in the frontal cortex of patients with diffuse LB disease. Our investigation represents the first extensive proteomic investigation of cortical LBs, and it is expected that characterization of the proteins in the cortical LBs may reveal novel mechanisms by which LB forms and pathways leading to neurodegeneration in DLB and/or advanced PD. Further investigation of these novel candidates is also necessary to ensure that the potential proteins in cortical LBs are not identified incorrectly because of incomplete current human protein database.

Quantification of total mitochondrial DNA and mitochondrial common deletion in the frontal cortex of patients with schizophrenia and bipolar disorder

Data published during the last decade are suggestive of a role for mitochondrial dysfunction in the pathogenesis of schizophrenia, bipolar disorder and other psychiatric diseases. In order to determine if the mitochondrial deficits reported in the literature are caused by abnormalities in the mitochondrial DNA of psychiatric patients, we quantified mitochondrial DNA (mtDNA) levels and the 5 kb common mitochondrial deletion (CD) in postmortem frontal cortex tissue. The mitochondrial CD and mtDNA levels were measured in tissue obtained from the frontal cortex (Brodmann Area 46) of 144 individuals (45 patients with schizophrenia, 40 patients with bipolar disorder, 44 controls, and 15 patients with major depression). These variables were measured using newly developed SYBR green and TaqMan real time PCR assays. Both the TaqMan and the SYBR green assays gave similar results. There was no statistically significant difference for the quantity of the common mitochondrial deletion between controls and patients. We also did not detect a difference in the mtDNA levels amongst the diagnosis groups. There were statistically significant differences for the evaluated parameters for smokers, schizophrenic patients on antipsychotic drugs at time of death, and bipolar patients with antidepressant use and alcohol abuse. Based on this study and other reports, we conclude that neither the common mitochondrial deletion nor changes in mitochondrial DNA levels are likely to account for the mitochondrial changes associated with bipolar disorder or schizophrenia. The effect of premortem agonal factors and medication on mitochondrial dysfunction still needs further elucidation.