Performance of various mathematical functions for the in-situ relative detector efficiency towards its applicability for k0 IM-NAA.

The in-situ relative detection efficiency strongly influences the characteristics of the k0-based internal monostandard neutron activation analysis (IM-NAA). In the present work, various mathematical functions were explored for the establishment of in-situ relative detector efficiency calibration and compared their performance based on the reduced chi-square (χ2) values. Among the various mathematical functions, the polynomial logarithm with 6th order was found to be associated with the minimum mean standard deviation for the experimental data and the lowest value of reduced χ2 after carrying out multiple iterations using Nelder-Mead algorithm. Quality assurance of the function was tested by carrying out elemental quantification of the NIST SRM 1633b coal fly ash. Gamma energies of the activation products, 152mEu, 59Fe, 140La, 24Na and 46Sc of the irradiated NIST standard were used for the in-situ relative full energy peak efficiency calibration of 30% HPGe detector. The sample was counted for different time intervals for the complete profiling of the elements present in the NIST SRM. The deviations for most of the elements were found to be within ±5% with respect to the certified values and ξ-score values were within ±2, demonstrating its better accuracy. This method was also applied satisfactorily to profile the elemental concentrations of alloy materials used in a thermal sensor guide tube of the steam generator in a test reactor.

Cephalic index, facial index and dental parameters: A correlative study to evaluate their significance in facial reconstruction.

Background: It becomes extremely challenging for forensic artists to reconstruct the highly decomposed faces, especially during mass disasters. It would be of great help for the identifying team of experts if there was a method to determine the facial and cephalic dimensions. This study aims to provide a method to generate a simplified method to calculate the facial and cephalic indices of an individual based on the dentition since human dentition remains almost intact in most scenarios. Materials and Methods: The sample consisted of 200 participants with the age range of 18-23 years belonging to Kerala. The cephalic and facial indices were measured using a caliper. The interincisal, intercanine, interpremolar and intermolar widths of maxillary dentition were measured on study models using a digital vernier caliper. The mean cranial and facial index were calculated and were correlated with interdental measurements. Results: It was concluded that dominant head types in Kerala males were dolichocephalic (50.2%) followed by mesocephalic (29.8%). In females, the dominant head types were dolichocephalic (42.7%) followed by mesocephalic (42.2%). In the facial types, majority of individuals were found to be leptoprosopic. A good correlation was found between the intercanine width with facial width and cranial width and a simplified formula were derived to estimate the cranial and facial index for this population. Conclusion: The results of the study suggest that the facial index and cranial index of a particular population can be evaluated from interdental measurements of the maxillary cast, especially the intercanine width.

Retraction Note: n-3 polyunsaturated fatty acid deprivation in rats decreases frontal cortex BDNF via a p38 MAPK-dependent mechanism.

This article1 has been retracted by the editor because an investigation by the National Institutes of Health concluded that the data represented by Figures 2a-c and 3e and Figure 4a were falsified. JT Arnold, SI Rapoport, RN Ertley, and RP Bazinet agree with this retraction. JS Rao and H-J Lee could not be reached for comment.

Chronic fluoxetine upregulates activity, protein and mRNA levels of cytosolic phospholipase A2 in rat frontal cortex.

This corrects the article DOI: 10.1038/sj.tpj.6500391.

Studies on neutron spectrum characterization for the Pneumatic Fast Transfer System (PFTS) of KAMINI reactor.

Characterization of neutron energy spectrum along with the determination of sub-cadmium to epithermal neutron flux ratio (f) and the epithermal neutron flux shape factor (α) has been carried out at pneumatic fast transfer system (PFTS) of KAMINI reactor. The facility has been extensively used for the neutron activation analysis (NAA) studies using both k0-NAA and relative method. This paper describes the multi-foil activation method to determine the reaction rates followed by the generation of computed guess spectrum to unfold the neutron spectrum using least square minimization approach.

Longitudinal evaluation of functional connectivity variation in the monkey sensorimotor network induced by spinal cord injury.

AIM: Given the unclear pattern of cerebral function reorganization induced by spinal cord injury (SCI), this study aimed to longitudinally evaluate the changes in resting-state functional connectivity (FC) in the sensorimotor network after SCI and explore their relationship with gait performance. METHODS: Four adult female rhesus monkeys were examined using resting-state functional magnetic resonance imaging during their healthy stage and after hemitransected SCI (4, 8 and 12 weeks after SCI), and the gait characteristics of their hindlimbs were recorded (except 4 weeks after SCI). Twenty sensorimotor-related cortical areas were adopted in the FC analysis to evaluate the functional network reorganization. Correlation analyses were then used to explore the relationship between functional network variations and gait characteristic changes. RESULTS: Compared with that during the healthy stage, the FC strength during post-SCI period was significantly increased in multiple areas of the motor control network, including the primary sensorimotor cortex, supplementary motor area (SMA) and putamen (Pu). However, the FC strength was remarkably reduced in the thalamus and parieto-occipital association cortex of the sensory network 8 weeks after SCI. Most FC intensities gradually approached the normal level 12 weeks after the SCI. Correlation analyses revealed that the enhanced FC strength between Pu and SMA in the left hemisphere, which regulates motor functions of the right side, was negatively correlated with the gait height of the right hindlimb. CONCLUSION: The cerebral functional network presents an adjust-recover pattern after SCI, which may help us further understand the cerebral function reorganization after SCI.

Irradiation-induced angiogenesis is associated with an MMP-9-miR-494-syndecan-1 regulatory loop in medulloblastoma cells.

Matrix metalloproteinase-9 (MMP-9) represents one of the most prominent proteins associated with tumorigenesis and is a modulator of the tumor microenvironment during angiogenesis. Recently, syndecan-1 (SDC1), a transmembrane heparan sulfate-bearing proteoglycan, was also speculated to have a critical role in contributing to angiogenesis when associated with MMP-9. However, the mechanism behind their synergistic regulation is not fully understood. In the current study, we report for the first time that ionizing radiation (IR)-induced MMP-9 enhances SDC1 shedding, corroborating to tube-inducing ability of medulloblastoma (MB) cells. Furthermore, we observed that the tumor angiogenesis is associated with higher MMP-9-SDC1 interactions on both the cell surface and extracellular medium. Our results also revealed the existence of a novel regulatory mechanism where MMP-9 drives the suppression of miR-494, resulting in enhanced SDC1 shedding and angiogenesis. From the in situ hybridization analysis, we found that MMP-9-specific shRNA (shMMP-9) treatment of mouse intracranial tumors resulted in elevated expression of miR-494. This negative correlation between MMP-9 and miR-494 levels was observed to be dependent on the methylation status of a miR-494 promoter-associated CpG island region (-186 to -20), which was confirmed by bisulfite-sequencing and methylation-specific PCR (MSP) analysis. Further, validation of MMP-9 and SDC1 3'-untranslated region (3'-UTR) targets with luciferase reporter assay provided a more favorable result for miR-494-mediated regulation of SDC1 but not of MMP-9, suggesting that the 3'-UTR of SDC1 mRNA is a direct target of miR-494. Overall, our results indicate that angiogenesis induced by radiotherapy is associated with an MMP-9-miR-494-SDC1 regulatory loop and that MMP-9-SDC1 activity creates a negative feedback loop by regulating the expression of miR-494.

RanBP9 aggravates synaptic damage in the mouse brain and is inversely correlated to spinophilin levels in Alzheimer's brain synaptosomes.

We previously demonstrated that overexpression of RanBP9 led to enhanced Aß generation in a variety of cell lines and primary neuronal cultures, and subsequently, we confirmed increased amyloid plaque burden in a mouse model of Alzheimer's disease (AD). In the present study, we found striking reduction of spinophilin protein levels when RanBP9 is overexpressed. At 12 months of age, we found spinophilin levels reduced by 70% (P<0.001) in the cortex of APΔE9/RanBP9 mice compared with that in wild-type (WT) controls. In the hippocampus, the spinophilin levels were reduced by 45% (P<0.01) in the APΔE9/RanBP9 mice. Spinophilin immunoreactivity was also reduced by 22% (P<0.01) and 12% (P<0.05) in the cortex of APΔE9/RanBP9 and APΔE9 mice, respectively. In the hippocampus, the reductions were 27% (P<0.001) and 14% (P<0.001) in the APΔE9/RanBP9 and APΔE9 mice, respectively. However, in the cerebellum, spinophilin levels were not altered in either APΔE9 or APΔE9/RanBP9 mice. Additionally, synaptosomal functional integrity was reduced under basal conditions by 39% (P<0.001) in the APΔE9/RanBP9 mice and ~23% (P<0.001) in the APΔE9 mice compared with that in WT controls. Under ATP- and KCl-stimulated conditions, we observed higher mitochondrial activity in the WT and APΔE9 mice, but lower in the APΔE9/RanBP9 mice. Significantly, we confirmed the inverse relationship between RanBP9-N60 and spinophilin in the synaptosomes of Alzheimer's brains. More importantly, both APΔE9 and APΔE9/RanBP9 mice showed impaired learning and memory skills compared to WT controls. These data suggest that RanBP9 might play a crucial role in the loss of spines and synapses in AD.

Tumor-associated soluble uPAR-directed endothelial cell motility and tumor angiogenesis.

The expression of urokinase-type plasminogen activator (uPA) receptor (uPAR) correlates with the malignant phenotype of various cancers. The soluble form of uPAR (s-uPAR) is present in the circulation of cancer patients, but the role of s-uPAR in endothelial cell migration is poorly understood. Therefore, we examined the role of tumor-associated s-uPAR on endothelial cell motility and angiogenesis. Here, we present evidence that tumor-associated s-uPAR augments the migration of human umbilical vein endothelial cells (HUVECs). When grown on tumor-conditioned medium, the membrane fraction of HUVECs had increased localization of s-uPAR onto its cell membrane. Colocalization studies for GM1 ganglioside receptor and uPAR further demonstrated s-uPAR recruitment onto lipid rafts of HUVECs. Immunoblot analysis for uPAR in lipid raft fractions confirmed s-uPAR recruiting onto HUVECs' membrane. Further, s-uPAR induced Rac1-mediated cell migration while either function-blocking uPAR antibodies or dominant-negative mutant Rac1 expression in HUVECs-mitigated s-uPAR-enhanced cell migration. In addition, orthotopic implantation of uPAR-overexpressing cells resulted in a significant increase in circulating s-uPAR in blood serum and invasive nature of tumor and tumor vasculature in mice. Collectively, this data provide insight into tumor-associated s-uPAR-directed migration of endothelial cells and its subsequent influence on tumor angiogenesis.

DREB1A promotes root development in deep soil layers and increases water extraction under water stress in groundnut.

Water deficit is a major yield-limiting factor for many crops, and improving the root system has been proposed as a promising breeding strategy, although not in groundnut (Arachis hypogaea L.). The present work was carried out mainly to assess how root traits are influenced under water stress in groundnut, whether transgenics can alter root traits, and whether putative changes lead to water extraction differences. Several transgenic events, transformed with DREB1A driven by the rd29 promoter, along with wild-type JL24, were tested in a lysimeter system that mimics field conditions under both water stress (WS) and well-watered (WW) conditions. The WS treatment increased the maximum rooting depth, although the increase was limited to about 20% in JL24, compared to 50% in RD11. The root dry weight followed a similar trend. Consequently, the root dry weight and length density of transgenics was higher in layers below 100-cm depth (Exp. 1) and below 30 cm (Exp. 2). The root diameter was unchanged under WS treatment, except a slight increase in the 60-90-cm layer. The root diameter increased below 60 cm in both treatments. In the WW treatment, total water extraction of RD33 was higher than in JL24 and other transgenic events, and somewhat lower in RD11 than in JL24. In the WS treatment, water extraction of RD2, RD11 and RD33 was higher than in JL24. These water extraction differences were mostly apparent in the initial 21 days after treatment imposition and were well related to root length density in the 30-60-cm layer (R(2) = 0.68), but not to average root length density. In conclusion, water stress promotes rooting growth more strongly in transgenic events than in the wild type, especially in deep soil layers, and this leads to increased water extraction. This opens an avenue for tapping these characteristics toward the improvement of drought adaptation in deep soil conditions, and toward a better understanding of genes involved in rooting in groundnut.

Role of MMP-2 in the regulation of IL-6/Stat3 survival signaling via interaction with α5ß1 integrin in glioma.

Matrix metalloproteinase-2 (MMP-2) has pivotal role in the degradation of extracellular matrix, and thereby enhances the invasive, proliferative and metastatic potential in cancer. Knockdown of MMP-2 using MMP-2 small interfering RNA (pM) in human glioma xenograft cell lines 4910 and 5310 decreased cell proliferation compared with mock and pSV (scrambled vector) treatments, as determined by 5-bromo-2'-deoxyuridine incorporation, Ki-67 staining and clonogenic survival assay. Cytokine array and western blotting using tumor-conditioned media displayed modulated secretory levels of various cytokines including granulocyte-macrophage colony-stimulating factor, interleukin-6 (IL-6), IL-8, IL-10, tumor necrosis factor-α, angiogenin, vascular endothelial growth factor and PDGF-BB in MMP-2 knockdown cells. Further, cDNA PCR array indicated potential negative regulation of Janus kinase/Stat3 pathway in pM-treated cells. Mechanistically, MMP-2 is involved in complex formation with α5 and ß1 integrins and MMP-2 downregulation inhibited α5ß1 integrin-mediated Stat3 phosphorylation and nuclear translocation. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays showed inhibited Stat3 DNA-binding activity and recruitment at CyclinD1 and c-Myc promoters in pM-treated cells. In individual experiments, IL-6 or siRNA-insensitive MMP-2 overexpression by pM-FL-A141G counteracted and restored the pM-inhibited Stat3 DNA-binding activity, suggesting IL-6/Stat3 signaling suppression in pM-treated 4910 and 5310 cells. MMP-2/α5ß1 binding is enhanced in human recombinant MMP-2 treatments, resulting in elevated Stat3 DNA-binding activity and recruitment on CyclinD1 and c-Myc promoters. Activation of α5ß1 signaling by Fibronectin adhesion elevated pM-inhibited Stat3 phosphorylation whereas blocking α5ß1 abrogated constitutive Stat3 activation. In vivo experiments with orthotropic tumor model revealed the decreased tumor size in pM treatment compared with mock or pSV treatments. Immunofluorescence studies in tumor sections corroborated our in vitro findings evidencing high expression and co-localization of MMP-2/α5ß1, which is decreased upon pM treatment along with significantly reduced IL-6, phospho-Stat3, CyclinD1, c-Myc, Ki-67 and PCNA expression levels. Our data indicate the possible role of MMP-2/α5ß1 interaction in the regulation of α5ß1-mediated IL-6/Stat3 signaling activation and signifies the therapeutic potential of blocking MMP-2/α5ß1 interaction in glioma treatment.

Essential role of cooperative NF-κB and Stat3 recruitment to ICAM-1 intronic consensus elements in the regulation of radiation-induced invasion and migration in glioma.

Although radiotherapy improves survival in patients, glioblastoma multiformes (GBMs) tend to relapse with augmented tumor migration and invasion even after ionizing radiation (IR). Aberrant nuclear factor-κB (NF-κB) and signal transducer and activator of transcription factor 3 (Stat3) activation and interaction have been suggested in several human tumors. However, possible NF-κB/Stat3 interaction and the role of Stat3 in maintenance of NF-κB nuclear retention in GBM still remain unknown. Stat3 and NF-κB (p65) physically interact with one another in the nucleus in glioma tumors. Most importantly, glutathione S-transferase pull-down assays identified that Stat3 binds to the p65 transactivation domain and is present in the NF-κB DNA-binding complex. Irradiation significantly elevated nuclear phospho-p65/phospho-Stat3 interaction in correlation with increased intercellular adhesion molecule-1 (ICAM-1) and soluble-ICAM-1 levels, migration and invasion in human glioma xenograft cell lines 4910 and 5310. Chromatin immunopreicipitation and promoter luciferase activity assays confirmed the critical role of adjacent NF-κB (+399) and Stat3 (+479) binding motifs in the proximal intron-1 in elevating IR-induced ICAM-1 expression. Specific inhibition of Stat3 or NF-κB with Stat3.siRNA or JSH-23 severely inhibited IR-induced p65 recruitment onto ICAM-1 intron-1 and suppressed migratory properties in both the cell lines. On the other hand, Stat3C- or IR-induced Stat3 promoter recruitment was significantly decreased in p65-knockdown cells, thereby suggesting the reciprocal regulation between p65 and Stat3. We also observed a significant increase in NF-κB enrichment on ICAM-1 intron-1 and ICAM-1 transactivation in Stat3C overexpressing cells. In in vivo orthotopic experiments, suppression of tumor growth in Stat3.si+IR-treated mice was associated with the inhibition of IR-induced p-p65/p-Stat3 nuclear colocalization and ICAM-1 levels. To our knowledge, this is the first study showing the crucial role of NF-κB/Stat3 nuclear association in IR-induced ICAM-1 regulation and implies that targeting NF-κB/Stat3 interaction may have future therapeutic significance in glioma treatment.

Functional cooperativity by direct interaction between PAK4 and MMP-2 in the regulation of anoikis resistance, migration and invasion in glioma.

Gliomas display anoikis resistance, enhanced invasion in to the adjacent brain parenchyma and eventually recur despite using the standard therapies. Our studies on increased anoikis sensitization in matrix metalloproteinase-2 (MMP-2)-knockdown 4910 and 5310 human glioma xenograft cells were interestingly correlated with p21-activated kinase 4 (PAK4) inhibition, prompting us to further investigate the role of PAK4 in glioma. Here, we report the PAK4 upregulation in positive correlation with increasing glioma pathological grades. The siRNA-mediated PAK4 knockdown elevated anoikis, and inhibited invasion and migration by downregulating MMP-2, αvß3-integrin and phospho-epidermal growth factor receptor (phospho-EGFR). The cDNA-PCR arrays revealed a transcriptional suppression of essential proteins involved in cell proliferation and adhesion in PAK4-knockdown cells. Most importantly, glutathione S-transferase pull-down assays demonstrated the MMP-2 as a new PAK4-interacting protein which binds to PAK4 kinase domain. Individual EGFR/ErbB2 inhibitor and αvß3 antibody treatments in PAK4si-treated cells indicated the regulation of αvß3/EGFR survival signaling by PAK4. Overexpression of PAK4 significantly reversed the MMP2si-induced cell death in both cell lines. Codepletion of PAK4 and MMP-2 resulted in robust anoikis-mediated cell death, and severely inhibited invasive and migratory properties in these cells. PAK4si inhibited in vivo tumor growth in nude mice by inhibiting MMP-2, ß3-integrin and phospho-EGFR levels in tumors. Our findings indicate a physical association between PAK4 and MMP-2, and suggest the future therapeutic potential of PAK4/MMP-2 dual targeting in glioma treatment.

uPAR and cathepsin B shRNA impedes TGF-ß1-driven proliferation and invasion of meningioma cells in a XIAP-dependent pathway.

Overexpression of transforming growth factor ß1 (TGF-ß1) has been linked to immune suppression, tumor angiogenesis, tumor cell migration, tumor cell survival, and tumor cell invasion in many cancers. In the present study, we found abundant expression of TGF-ß1 in the microenvironment of four different pathological types of meningioma tumors. TGF-ß1 induced invasion in malignant meningioma cells with an associated upregulation of urokinase-type plasminogen activator (uPA), uPAR, cathepsin B, and MMP-9, and this increase in proliferation was coupled with the expression of anti-apoptotic and pro-survival signaling molecules. In addition to the intense immunoreactivity of meningioma tumors to X-linked inhibitor to apoptosis (XIAP), its knockdown abolished the TGF-ß1-induced proliferation of these cells. The stimulation of XIAP expression and the activation of pSMAD-2 is mediated by phosphatidylinositol 3-kinase (PI3K)- and MEK-dependent pathways, and the addition of anti-TGF-ß1 antibodies prevented their expression with a consequent decrease in invasion. Bicistronic shRNA constructs targeting uPAR and cathepsin B (pUC) quenched TGF-ß1-driven invasion and survival of meningioma cells by downregulation of XIAP and pSMAD-2 expression. Animal models with intracranial tumors showed elevated levels of TGF-ß1, XIAP and pSMAD-2, and pUC treatment prevented this increased expression. Thus, targeted silencing of TGF-ß1-induced signaling by pUC in meningioma would provide new treatment approaches for management of meningioma.

Epigenetic modifications in frontal cortex from Alzheimer's disease and bipolar disorder patients.

Alzheimer's disease (AD) and bipolar disorder (BD) are progressive brain disorders. Upregulated mRNA and protein levels of neuroinflammatory and arachidonic acid (AA) markers with loss of synaptic markers (synaptophysin and drebrin) have been reported in brain tissue from AD and BD patients. We hypothesized that some of these changes are associated with epigenetic modifications of relevant genes. To test this, we measured gene-specific CpG methylation, global DNA methylation and histone modifications in postmortem frontal cortex from BD (n=10) and AD (n=10) patients and respective age-matched controls (10 per group). AD and BD brains showed several epigenetic similarities, including global DNA hypermethylation, and histone H3 phosphorylation. These changes were associated with hypo- and hypermethylation of CpG islands in cyclooxygenase-2 and brain-derived neurotrophic factor promoter regions, respectively. Only the AD brain showed hyper- and hypomethylated CpG islands in promoter regions for cAMP response element-binding protein and nuclear transcription factor kappa B genes, respectively. Only the BD brain demonstrated increased global histone H3 acetylation and hypermethylation of the promotor region for the drebrin-like protein gene. There was no significant epigenetic modification for 12-lipooxygenase or p450 epoxygenase in either illness. Many observed epigenetic changes were inversely related to respective changes in mRNA and protein levels. These epigenetic modifications involving neuroinflammatory, AA cascade and synaptic markers may contribute to progression in AD and BD and identify new targets for drug development.

Cathepsin B and uPAR knockdown inhibits tumor-induced angiogenesis by modulating VEGF expression in glioma.

Angiogenesis, which is the process of sprouting of new blood vessels from pre-existing vessels, is vital for tumor progression. Proteolytic remodeling of extracellular matrix is a key event in vessel sprouting during angiogenesis. Urokinase type plasminogen activator receptor (uPAR) and cathepsin B are both known to be overexpressed and implicated in tumor angiogenesis. In the present study, we observed that knockdown of uPAR and cathepsin B using puPAR (pU), pCathepsin B (pC), and a bicistronic construct of uPAR and cathepsin B (pCU) caused significant inhibition of angiogenesis by disrupting the janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway-dependent expression of vascular endothelial growth factor (VEGF). Further, transcriptional suppression of uPAR and cathepsin B inhibited tumor-induced migration, proliferation of endothelial cells and decreased tumor-promoted expression of VEGF receptor-2, Rac1, gp91phox, cyclin D1, cyclin dependent kinase 4 and p-Rb in human dermal microvascular endothelial cell. Furthermore, U251 and SNB19 xenograft tissue sections from nude mice treated with pCU showed reduced expression of VEGF and CD31, which is a blood vessel visualization marker. Overall, results revealed that knockdown of uPAR and cathepsin B inhibited tumor-induced angiogenesis by disrupting the JAK/STAT pathway-dependent expression of VEGF. These data provide new insight in characterizing the pathways involved in the angiogenic cascade and for the identification of novel target proteins for use in therapeutic intervention for gliomas.

MMP-2 mediates mesenchymal stem cell tropism towards medulloblastoma tumors.

Matrix metalloproteinases (MMPs) are a family of proteinases known to have a role in cell migration. In the present study, we evaluated the role of MMP-2 on tropism of human umbilical cord blood-derived stem cells (hUCBSCs) in a human medulloblastoma tumor model. Consequences of MMP-2 inhibition on stem cell tropism towards medulloblastoma were studied in terms of stem cell migration by using cell culture inserts, transwell chamber assay, western blotting for MMP-2 and migratory molecules, and immunohistochemistry. Conditioned medium from Daoy/D283 cells infected with adenoviral vector encoding MMP-2 small interfering RNA (siRNA) (Ad-MMP-2 si)-reduced stem cell migration as compared with conditioned medium from mock and scrambled vector (Ad-SV) infected cells. In addition, MMP-2 inhibition in the tumor cells decreased the expression of stromal cell-derived factor 1 (SDF1) in the tumor-conditioned medium, which results in impaired SDF1/CXCR4 signaling leading to decreased stem cell tropism towards the tumor cells. We further show that MMP-2 inhibition in the tumor cells repressed stem cell tropism towards medulloblastoma tumors in vivo. In summary, we conclude that hUCBSCs can integrate into human medulloblastoma after local delivery and that MMP-2 expression by the tumor cells mediates this response through the SDF1/CXCR4 axis.

Altered neuroinflammatory, arachidonic acid cascade and synaptic markers in postmortem Alzheimer's disease brain.

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. A recent positron emission tomography imaging study demonstrated upregulated brain arachidonic acid (AA) metabolism in AD patients. Further, a mouse model of AD shows an increase in AA-releasing cytosolic phospholipase A(2) (cPLA(2)) in brain, and a reduction in cPLA(2) activity ameliorated cognitive deficits. These observations led us to hypothesize that there is an upregulation of AA cascade and neuroinflammatory markers in the brain of AD patients. To test this hypothesis, we measured protein and mRNA levels of AA cascade, neuroinflammatory and synaptic markers in postmortem frontal cortex from 10 AD patients and 10 age-matched controls. Consistent with our hypothesis, AD frontal cortex showed significant increases in protein and mRNA levels of cPLA(2)-IVA, secretory sPLA(2)-IIA, cyclooxygenase-1 and -2, membrane prostaglandin (PG) synthase-1 and lipoxygenase-12 and -15. Calcium-independent iPLA(2)-VIA and cytosolic PGE(2) synthase were decreased. In addition, interleukin-1ß, tumor necrosis factor-α, glial fibrillary acidic protein and CD11b were increased. AD postmortem brain also showed signs of cellular injury, including decreased synaptophysin and drebrin, pre- and postsynaptic markers. These results indicate that increased AA cascade and inflammatory markers could contribute to AD pathology. Altered brain AA cascade enzymes could be considered therapeutic targets for future drug development.

Altered arachidonic acid cascade enzymes in postmortem brain from bipolar disorder patients.

Mood stabilizers that are approved for treating bipolar disorder (BD), when given chronically to rats, decrease expression of markers of the brain arachidonic metabolic cascade, and reduce excitotoxicity and neuroinflammation-induced upregulation of these markers. These observations, plus evidence for neuroinflammation and excitotoxicity in BD, suggest that arachidonic acid (AA) cascade markers are upregulated in the BD brain. To test this hypothesis, these markers were measured in postmortem frontal cortex from 10 BD patients and 10 age-matched controls. Mean protein and mRNA levels of AA-selective cytosolic phospholipase A(2) (cPLA(2)) IVA, secretory sPLA(2) IIA, cyclooxygenase (COX)-2 and membrane prostaglandin E synthase (mPGES) were significantly elevated in the BD cortex. Levels of COX-1 and cytosolic PGES (cPGES) were significantly reduced relative to controls, whereas Ca(2+)-independent iPLA(2)VIA, 5-, 12-, and 15-lipoxygenase, thromboxane synthase and cytochrome p450 epoxygenase protein and mRNA levels were not significantly different. These results confirm that the brain AA cascade is disturbed in BD, and that certain enzymes associated with AA release from membrane phospholipid and with its downstream metabolism are upregulated. As mood stabilizers downregulate many of these brain enzymes in animal models, their clinical efficacy may depend on suppressing a pathologically upregulated cascade in BD. An upregulated cascade should be considered as a target for drug development and for neuroimaging in BD.