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Abstract: Degradation of glycerophospholipids, sphingolipids and cholesterol in the nucleus modulates neural cell proliferation and differentiation, inflammation, apoptosis, migration, cell adhesion, and intracellular trafficking. Extracellular signals from agonists (neurotransmitters, cytokines, and growth factors) regulate the activity of a key set of lipid-metabolizing enzymes, such as phospholipases, sphingomyelinases, and cholesterol hydroxylases. These enzymes and their downstream targets constitute a complex lipid signaling network with multiple nodes of interaction and cross-regulation through their lipid mediators, which include eicosanoids, docosanoids, diacylglycerols, platelet activating factor, lysophosphatidic acid, ceramide and ceramide 1-phosphate, sphingosine and sphingosine 1-phosphate, and hydroxycholesterols. Receptors for above lipid mediators are localized at the neural cell nucleus. Stimulation of isolated nuclei with these lipids and agonists results in changes in transcriptional regulation of major genes, including c-fos, cylooxygenase-2, secretory phospholipase A2 and endothelial as well as inducible nitric oxide synthases. Imbalances in signaling network involving above genes may contribute to the pathogenesis of human neurological disorders. In this review, we have attempted to integrate available information on above lipid mediators in the nucleus. In addition, attempts have been made to explain cross-talk among glycerophospholipid-, sphingolipid-, and cholesterol-derived lipid mediators in neural cell death in Alzheimer''s disease. [Copyright &y& Elsevier]

Abstract: The transcription factor sterol regulatory element binding protein-2 (SREBP-2) has a key role in regulating cholesterol biosynthesis. In view of ongoing cholesterol biosynthesis in the brain, the present study was carried out to examine the distribution of the SREBP-2 in the normal rat brain, and possible changes after kainate-induced excitotoxicity. Western immunoblot analysis of SREBP-2 showed a dense band at 70kDa corresponding to the transcriptionally active form of SREBP-2 in homogenates from the rat hippocampus, cortex and striatum. SREBP-2 immunolabeled sections showed dense labeling of pyramidal neurons in field CA1 and CA3 of the hippocampus, moderately dense labeling of pyramidal and non-pyramidal neurons of the cerebral neocortex, and moderate labeling of putative medium spiny neurons in the caudate nucleus and putamen. Label was observed in the somatic cytoplasm, nucleus and apical dendrites of pyramidal neurons, and dendritic shafts and spines in the neuropil in the hippocampus. The expression of SREBP-2 was also elucidated after excitotoxic neuronal injury induced by intracerebroventricular injections of kainate. Real time RT-PCR analyses showed that mRNA level of SREBP-2 was significantly reduced at both 1 day and 2 weeks post-kainate injection. Immunohistochemical analyses showed significantly reduced SREBP-2 immunoreactivity in the kainate-induced lesions, in support of the real time RT-PCR results. Taken together, the above results show that there is high level of SREBP-2 expression in the normal hippocampus, and that neuronal injury results in a significant reduction of SREBP-2 expression in the damaged areas. [Copyright &y& Elsevier]

Abstract: Neural membranes are composed of glycerophospholipids, sphingolipids, cholesterol and proteins. The distribution of these lipids within the neural membrane is not random but organized. Neural membranes contain lipid rafts or microdomains that are enriched in sphingolipids and cholesterol. These rafts act as platforms for the generation of glycerophospholipid-, sphingolipid-, and cholesterol-derived second messengers, lipid mediators that are necessary for normal cellular function. Glycerophospholipid-derived lipid mediators include eicosanoids, docosanoids, lipoxins, and platelet-activating factor. Sphingolipid-derived lipid mediators include ceramides, ceramide 1-phosphates, and sphingosine 1-phosphate. Cholesterol-derived lipid mediators include 24-hydroxycholesterol, 25-hydroxycholesterol, and 7-ketocholesterol. Abnormal signal transduction processes and enhanced production of lipid mediators cause oxidative stress and inflammation. These processes are closely associated with the pathogenesis of acute neural trauma (stroke, spinal cord injury, and head injury) and neurodegenerative diseases such as Alzheimer disease. Statins, the HMG-CoA reductase inhibitors, are effective lipid lowering agents that significantly reduce risk for cardiovascular and cerebrovascular diseases. Beneficial effects of statins in neurological diseases are due to their anti-excitotoxic, antioxidant, and anti-inflammatory properties. Fish oil ω-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, have similar anti-excitotoxic, antioxidant and anti-inflammatory effects in brain tissue. Thus the lipid mediators, resolvins, protectins, and neuroprotectins, derived from eicosapentaenoic acid and docosahexaenoic acid retard neuroinflammation, oxidative stress, and apoptotic cell death in brain tissue. Like statins, ingredients of fish oil inhibit generation of β-amyloid and provide protection from oxidative stress and inflammatory processes. Collective evidence suggests that antioxidant, anti-inflammatory, and anti-apoptotic properties of statins and fish oil contribute to the clinical efficacy of treating neurological disorders with statins and fish oil. We speculate that there is an overlap between neurochemical events associated with neural cell injury in stroke and neurodegenerative diseases. This commentary compares the neurochemical effects of statins with those of fish oil. [Copyright &y& Elsevier]

Although many studies have identified a link between hypercholesterolemia or hypertension and cognitive deficits, till date, comprehensive gene expression analyses of the brain under these conditions is still lacking. The present study was carried out to elucidate differential gene expression changes in the prefrontal cortex (PFC) of New Zealand white rabbits exposed to hypercholesterolemia and/or hypertension with a view of identifying gene networks at risk. Microarray analyses of the PFC of hypercholesterolemic rabbits showed 850 differentially expressed genes (DEGs) in the cortex of hypercholesterolemic rabbits compared to controls, but only 5 DEGs in hypertensive rabbits compared to controls. Up-regulated genes in the PFC of hypercholesterolemic rabbits included CIDEC, ODF2, RNASEL, FSHR, CES3 and MAB21L3, and down-regulated genes included FAM184B, CUL3, LOC100351029, TMEM109, LOC100357097 and PFDN5. Comparison with our previous study on the middle cerebral artery (MCA) of the same rabbits showed many differentially expressed genes in common between the PFC and MCA, during hypercholesterolemia. Moreover, these genes tended to fall into the same functional networks, as revealed by IPA analyses, with many identical node molecules. These include: proteasome, insulin, Akt, ERK1/2, histone, IL12, interferon alpha and NFκB. Of these, PSMB4, PSMD4, PSMG1 were chosen as representatives of genes related to the proteasome for verification by quantitative RT-PCR. Results indicate significant downregulation of all three proteasome associated genes in the PFC. Immunostaining showed significantly increased number of Aβ labelled cells in layers III and V of the cortex after hypercholesterolemia and hypertension, which may be due to decreased proteasome activity and/or increased β- or γ-secretase activity. Knowledge of altered gene networks during hypercholesterolemia and/or hypertension could inform our understanding of the link between these conditions and cognitive deficits in vascular dementia or Alzheimer's disease. [ABSTRACT FROM AUTHOR]

The iron siderophore binding protein lipocalin 2 (LCN2, also known as 24p3, NGAL and siderocalin) may be involved in iron homeostasis, but to date, little is known about expression of its putative receptor, brain-type organic cation transporter (BOCT, also known as BOCT1, 24p3R, NGALR and LCN2R), in the brain during neurodegeneration. The present study was carried out to elucidate the expression of LCN2 and BOCT in hippocampus after excitotoxicity induced by the glutamate analog, kainate (KA) and a possible role of LCN2 in neuronal injury. As reported previously, a rapid and sustained induction in expression of LCN2 was found in the hippocampus after intracerebroventicular injection of KA. BOCT was expressed in neurons of the saline-injected control hippocampus, and immunolabel for BOCT protein was preserved in pyramidal neurons of CA1 at 1 day post-KA injection, likely due to the delayed onset of neurodegeneration after KA injection. At 3 days and 2 weeks after KA injections, loss of immunolabel was observed due to degenerated neurons, although remaining neurons continued to express BOCT, and induction of BOCT was found in OX-42 positive microglia. This resulted in an overall decrease in BOCT mRNA and protein expression after KA treatment. Increased expression of the pro-apoptotic marker, Bim, was found in both neurons and microglia after KA injection, but TUNEL staining indicating apoptosis was found primarily in Bim-expressing neurons, but not microglia. Interaction between LCN2 and BOCT was found by DuoLink assay in cultured hippocampal neurons. Apo-LCN2 without iron caused no significant differences in neuronal Bim expression or cell survival, whereas holo-LCN2 consisting of LCN2:iron:enterochelin complex increased Bim mRNA expression and decreased neuronal survival. Together, results suggest that LCN2 and BOCT may have a role in neuronal injury. [ABSTRACT FROM AUTHOR]

Abstract: Lipocalin 2 (LCN2) is produced by mammalian hosts to bind bacterial siderophore and sequester free iron as part of an innate immune response, and could also play a role in tissue iron homeostasis, but thus far, little is known about its expression in the CNS. The present study was carried out to study the expression of the lipocalin in the normal rat brain and after neuronal injury induced by kainate (KA). Low levels of LCN2 mRNA and protein expression were detected in most regions of the normal brain except the olfactory bulb, brainstem and cerebellum. KA lesions resulted in damage to the hippocampus, leading to an early increase at three days and a sustained elevation in LCN2 mRNA level of 16-fold, and protein expression at 80-fold in the lesioned tissue compared to controls at 2weeks post-KA injection. The sustained elevation in mRNA expression was not detected among other lipocalins surveyed using real-time RT-PCR – apoD, PGDS, Rbp4 and LCN5. Single and double immunostaining confirmed that LCN2 is present in astrocytes in the olfactory bulb, brainstem and cerebellum of the normal brain, and reactive astrocytes in the KA-lesioned hippocampus. In conclusion, the present study showed LCN2 to be present in select brain regions, and is upregulated in astrocytes after neuronal injury induced by kainate. We postulate that, as in the periphery, LCN2 may have a role in iron transport or trafficking in the CNS. [Copyright &y& Elsevier]

Abstract: The chakragati (ckr) mouse, which was serendipitously created as a result of a transgenic insertional mutation, has been proposed as a model of aspects of schizophrenia. The mice exhibit circling, hyperactivity, reduced social interactions, and enlarged lateral ventricles, which parallel aspects of the pathophysiology of schizophrenia. Deficits in sensorimotor gating and processing of the relevance of stimuli are core features of schizophrenia, which underlie many of the symptoms presented. Measures of prepulse inhibition (PPI) and latent inhibition (LI) can assess sensorimotor gating and processing of relevance in both humans and animal models. We investigated PPI of acoustic startle and LI of aversive conditioning in wild-type, heterozygous, and ckr mice. The ckr mice, which are homozygous for the transgene insertion, but not heterozygous littermates, showed impaired PPI in the absence of any difference in acoustic startle amplitude and showed deficits in LI of conditioning of a light stimulus to footshock, measured as suppression of licking for water in water-restricted mice. Together with the previous evidence for hyperactivity, reduced social interactions, and enlarged lateral ventricles, these data lend further support to the suggestion that the ckr mouse has utility as an animal model of aspects of schizophrenia. [Copyright &y& Elsevier]

Retinoic acid modulates a wide variety of biological processes including proliferation, differentiation, and apoptosis. It interacts with specific receptors in the nucleus, the retinoic acid receptors (RARs). The molecular mechanism by which retinoic acid mediates cellular differentiation and growth suppression in neural cells remains unknown. However, retinoic acid-induced release of arachidonic acid and its metabolites may play an important role in cell proliferation, differentiation, and apoptosis. In brain tissue, arachidonic acid is mainly released by the action of phospholipase A2 (PLA2) and phospholipase C (PLC)/diacylglycerol lipase pathways. We have used the model of differentiation in LA-N-1 cells induced by retinoic acid. The treatment of LA-N-1 cells with retinoic acid produces an increase in phospholipase A2 activity in the nuclear fraction. The pan retinoic acid receptor antagonist, BMS493, can prevent this increase in phospholipase A2 activity. This suggests that retinoic acid-induced stimulation of phospholipase A2 activity is a retinoic acid receptor-mediated process. LA-N-1 cell nuclei also have phospholipase C and phospholipase D (PLD) activities that are stimulated by retinoic acid. Selective phospholipase C and phospholipase D inhibitors block the stimulation of phospholipase C and phospholipase D activities. Thus, both direct and indirect mechanisms of arachidonic acid release exist in LA-N-1 cell nuclei. Arachidonic acid and its metabolites markedly affect the neurite outgrowth and neurotransmitter release in cells of neuronal and glial origin. We propose that retinoic acid receptors coupled with phospholipases A2, C and D in the nuclear membrane play an important role in the redistribution of arachidonic acid in neuronal and non-nuclear neuronal membranes during differentiation and growth suppression. Abnormal retinoid metabolism may be involved in the downstream transcriptional regulation of phospholipase A2-mediated signal transduction in schizophrenia and Alzheimer disease (AD). The development of new retinoid analogs with diminished toxicity that can cross the blood–brain barrier without harm and can normalize phospholipase A2-mediated signaling will be important in developing pharmacological interventions for these neurological disorders. [Copyright &y& Elsevier]

Abstract Lysophosphatidic acid receptor 1 (LPA 1) is one of six G protein-coupled receptors (GPCRs) activated by the bioactive lipid, lysophosphatidic acid (LPA). Previous studies have shown that LPA 1 signaling plays a major role in the pathophysiology of neuropathic pain. It has also been shown that the inhibition of phospholipase A 2 , an enzyme upstream of LPA synthesis, reduces mechanical allodynia in experimental inflammatory orofacial pain. This suggests that the LPA-LPA 1 axis may mediate inflammatory pain in addition to its known role in neuropathic pain, but this activity has not been reported. LPA 1 signaling was disrupted in mice with both genetic and pharmacological approaches. Mice were then evaluated for behavioral and molecular characteristics of allodynia in a model for inflammatory orofacial pain. Pain behavior was significantly attenuated in LPA 1 knockout mice relative to wild-type littermate controls. A similar significant attenuation in allodynia was observed when mice were treated with an LPA 1 antagonist, AM095, following validation of its potency and selectivity. This was accompanied by a marked reduction in phosphorylated cAMP response element-binding protein (pCREB) labelling in the cerebral cortex. Interestingly, the reduction in allodynia was observed with central, but not systemic drug administration. Taken together, our findings indicate that LPA 1 signaling in the central nervous system (CNS) plays a key role in mediating orofacial inflammatory pain, identifying LPA 1 as a potential therapeutic target for treating inflammatory pain with a brain-penetrant drug. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

The prefrontal cortex is essential for executive functions such as decision-making and planning. There is also accumulating evidence that it is important for the modulation of pain. In this study, we investigated a possible role of prefrontal cortical calcium-independent phospholipase A 2 (iPLA 2 ) in antinociception induced by the norepinephrine reuptake inhibitor (NRI) and tetracyclic (tricyclic) antidepressant, maprotiline. Intraperitoneal injections of maprotiline increased iPLA 2 mRNA and protein expression in the prefrontal cortex. This treatment also reduced grooming responses to von-Frey hair stimulation of the face after facial carrageenan injection, indicating decreased sensitivity to pain. The antinociceptive effect of maprotiline was abrogated by iPLA 2 antisense oligonucleotide injection to the prefrontal cortex, indicating a role of this enzyme in antinociception. In contrast, injection of iPLA 2 antisense oligonucleotide to the somatosensory cortex did not reduce the antinociceptive effect of maprotiline. Lipidomic analysis of the prefrontal cortex showed decrease in phosphatidylcholine species, but increase in lysophosphatidylcholine species, indicating increased PLA2 activity, and release of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) after maprotiline treatment. Differences in sphingomyelin/ceramide were also detected. These changes were not observed in maprotiline-treated mice that received iPLA 2 antisense oligonucleotide to the prefrontal cortex. Metabolites of DHA and EPA may help to strengthen a known supraspinal antinociceptive pathway from the prefrontal cortex to the periaqueductal gray. Together, results indicate a role of prefrontal cortical iPLA 2 and its enzymatic products in the antinociceptive effect of maprotiline. [ABSTRACT FROM AUTHOR]

To determine the role of ceruloplasmin (Cp) in epileptic seizures, we used a kainate (KA) seizure animal model and examined hippocampal samples from epileptic patients. Treatment with KA resulted in a time-dependent decrease in Cp protein expression in the hippocampus of rats. Cp-positive cells were colocalized with neurons or reactive astrocytes in KA-treated rats and epileptic patient samples. KA-induced seizures, initial oxidative stress (i.e., hydroxyl radical formation, lipid peroxidation, protein oxidation, and synaptosomal reactive oxygen species), altered iron status (increasing Fe 2+ accumulation and L-ferritin-positive reactive microglial cells and decreasing H-ferritin-positive neurons), and impaired glutathione homeostasis and neurodegeneration (i.e., Fluoro-Nissl and Fluoro-Jade B staining analyses) were more pronounced in Cp antisense oligonucleotide (ASO)- than in Cp sense oligonucleotide-treated rats. Consistently, Cp ASO facilitated KA-induced lactate dehydrogenase (LDH) release, Fe 2+ accumulation, and glutathione loss in neuron-rich and mixed cultures. However, Cp ASO did not alter KA-induced LDH release or Fe 2+ accumulation in the astroglial culture, but did facilitate impairment in glutathione homeostasis in the same culture. Importantly, treatment with human Cp protein resulted in a significant attenuation against these neurotoxicities induced by Cp ASO. Our results suggest that Cp-mediated neuroprotection occurs via the inhibition of seizure-associated oxidative damage (including impairment in glutathione homeostasis), Fe 2+ accumulation, and alterations in ferritin immunoreactivity. Moreover, interactive modulation between neurons and glia was found to be important for Cp upregulation in the attenuation of epileptic damage in both animals and humans. [ABSTRACT FROM AUTHOR]

Oxidative stress resulting from the generation of reactive oxygen species has been proposed as an etiological factor in schizophrenia. The present study tests the hypothesis that oxidative stress can affect levels of dysbindin-1A, encoded by Dtnbp1, a genetic risk factor for schizophrenia, via its PEST domain. In vitro studies on SH-SY5Y cells indicate that oxidative stress triggers proteasomal degradation of dysbindin-1A, and that this requires interactions with its PEST domain, which may be a TRIM32 target. We specifically found (a) that oxidative stress induced in SH-SY5Y cells by 500 µM hydrogen peroxide reduced levels of full-length dysbindin-1, but did not reduce levels of that protein lacking its PEST domain and (b) that levels of full-length dysbindin-1, but not dysbindin-1 lacking its PEST domain, were higher in cells treated with the proteasome inhibitor MG132. Oxidative stress thus emerges as the first known cellular factor regulating dysbindin-1 isoforms with PEST domains. These findings are consistent with the previously noted fact that phosphorylation of PEST domains often marks proteins for proteasomal degradation, and raises the possibility that treatments reducing oxidative stress in the brain, especially during development, may lower schizophrenia risk. [ABSTRACT FROM AUTHOR]

Calcium independent phospholipase A2 (iPLA2) is an 85 kDa protein that catalyzes the hydrolysis of the sn-2 acyl ester bond of glycerophospholipids to liberate free fatty acids and lysophospholipids. In this study, we determined the role of constitutive iPLA2β in long term potentiation (LTP) of the hippocampo-prefrontal cortical pathway in vivo . We also examined the effect of iPLA2β knockdown using the rewarded alternation in T-maze task, a test of spatial working memory which is dependent on this pathway. Intracortical injection of an inhibitor to iPLA2, bromoenol lactone (BEL) or antisense oligonucleotide to iPLA2β in the prefrontal cortex abolished induction of hippocampo-prefrontal cortical LTP. Moreover, iPLA2 inhibition and antisense knockdown resulted in increased errors in the rewarded alternation in T-maze task, indicating negative effects on spatial working memory. BEL or antisense injection did not produce DNA fragmentation in the cortex as demonstrated by TUNEL assay. Results confirm a role of constitutive iPLA2β in hippocampo-prefrontal cortical synaptic plasticity in vivo , and add to previous observations of a role of iPLA2 in hippocampal LTP in vitro , and long-term memory retrieval. They may be relevant in Alzheimer’s disease, and other neurodegenerative conditions that are associated with changes in iPLA2. [ABSTRACT FROM AUTHOR]

Abstract: Airborne engineered nanoparticles undergo agglomeration, and careful distinction must be made between primary and agglomerate size of particles, when assessing their health effects. This study compares the effects on rats undergoing 15-day inhalation exposure to airborne agglomerates of gold nanoparticles (AuNPs) of similar size distribution and number concentration (1 × 106 particles/cm3), but two different primary diameters of 7 nm or 20 nm. Inhalation of agglomerates containing 7-nm AuNPs resulted in highest deposition by mass concentration in the lungs, followed by brain regions including the olfactory bulb, hippocampus, striatum, frontal cortex, entorhinal cortex, septum, cerebellum; aorta, esophagus, and kidney. Eight organs/tissues especially the brain retained greater mass concentration of Au after inhalation exposure to agglomerates of 7-nm than 20-nm AuNPs. Macrophage mediated escalation followed by fecal excretion is the major pathway of clearing inhaled AuNPs in the lungs. Microarray analyses of the hippocampus showed mostly downregulated genes, related to the cytoskeleton and neurite outgrowth. Together, results in this study indicate disintegration of nanosized agglomerates after inhalation and show impact of primary size of particles on subsequent biodistribution. [Copyright &y& Elsevier]

Abstract: Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified followed by determining an optimal purification process and evaluating the stability as well as oxidation state of the purified 20-nm AuNPs. Quantified non-AuNP components and a newly speciated byproduct (acetate) complete the stoichiometric equation of AuNP synthesis through the citrate reduction method. Among the five tested centrifugation forces (3000–11,000g) and durations (10–60 min), optimal purification of AuNPs was achieved by centrifugation operating at 7000g for 20 min which satisfactorily recovers ∼80% of AuNPs without detectable impurities. Storage in the dark at 4 °C prolongs the stability of the purified AuNP suspensions up to 20 days. AuNPs employed in this study persist in their atomic status without being oxidized, even after they were aerosolized in air or heated at 500 °C. This work demonstrates how impurities are identified and removed, and the purified AuNPs can be a reference material to evaluate toxicity or reactivity of other engineered nanomaterials. [ABSTRACT FROM AUTHOR]

Abstract: Phospholipases A2 (PLA2) are enzymes which cleave the sn-2 ester bond in membrane phospholipids to release free fatty acids and lysophospholipids. The present study aimed to elucidate the expression profile of multiple secretory phospholipase A2 (sPLA2) isoforms in the normal rat CNS with focus on sPLA2-IIA in the brainstem and spinal cord. Quantitative RT-PCR analysis showed that sPLA2-IB expression was low throughout the CNS, sPLA2-IIA expression was high in the brainstem and spinal cord, sPLA2-IIC expression was high in the cerebral neocortex, hippocampus and thalamus/hypothalamus, sPLA2-V expression was high in the olfactory bulb and cerebellum, and sPLA2-X was expressed at very low levels in the normal CNS. Of the isoforms, sPLA2-IIA mRNA expression was highest in the brainstem and spinal cord suggesting that this could be the most relevant isoform in the ascending pain pathway. Western blot analysis showed high level of sPLA2-IIA expression in the brainstem and cervical, thoracic and lumbar spinal segments but low level of expression in other parts of the brain. sPLA2-IIA was localized by immunohistochemistry to the spinal trigeminal and facial motor nuclei and dorsal- and ventral-horns of the spinal cord. The enzyme was found on the endoplasmic reticulum of neuronal cell bodies and small diameter dendrites or dendritic spines at electron microscopy. The expression of sPLA2-IIA in the dorsal horn and spinal trigeminal nucleus is consistent with previous results which showed an important role of CNS sPLA2 in nociceptive transmission. [Copyright &y& Elsevier]

Abstract: Increase in levels of oxysterols or cholesterol oxidation products have been detected in brain areas undergoing neuroinflammation after excitotoxic injury, and the present study was carried out to elucidate possible effects of these products on exocytosis in rat pheochromocytoma-12 (PC12) cells. An increase in vesicle fusion with the cell membrane indicating exocytosis was observed by total internal reflection microscopy (TIRFM), and confirmed by capacitance measurements, after addition of 7 ketocholesterol, 24 hydroxycholesterol or cholesterol 5, 6 beta epoxide. 7 ketocholesterol induced exocytosis was attenuated by pretreatment with a disruptor of cholesterol-rich domains or “lipid rafts”, methyl-β-cyclodextrin (MβCD) as demonstrated by capacitance and amperometry measurements of neurotransmitter release. Moreover, treatment of cells with thapsigargin to deplete intracellular calcium, or treatment of cells with lanthanum chloride to block calcium channels resulted in attenuation of 7 ketocholesterol induced exocytosis. Fura-2 imaging showed that 7 ketocholesterol induced rapid and sustained increases in intracellular calcium concentration, and that this effect was attenuated in cells that were pre-treated with MβCD, thapsigargin or lanthanum chloride. Together, the results suggest that neurotransmitter release triggered by 7 ketocholesterol is dependent on the integrity of cholesterol rich lipid domains on cellular membranes and a rise in intracellular calcium, either through release from internal stores or influx via calcium channels. Increased cholesterol oxidation product concentrations in brain areas undergoing neuroinflammation may enhance exocytosis and neurotransmitter release, thereby aggravating excitotoxicity. [Copyright &y& Elsevier]

Abstract: Schizophrenia (SZ) and bipolar disorder (BD) are debilitating neurobehavioural disorders likely influenced by genetic and non-genetic factors and which can be seen as complex disorders of synaptic neurotransmission. The glutamatergic and GABAergic neurotransmission systems have been implicated in both diseases and we have reviewed extensive literature over a decade for evidence to support the association of glutamate and GABA genes in SZ and BD. Candidate-gene based population and family association studies have implicated some ionotrophic glutamate receptor genes (GRIN1, GRIN2A, GRIN2B and GRIK3), metabotropic glutamate receptor genes (such as GRM3), the G72/G30 locus and GABAergic genes (e.g. GAD1 and GABRB2) in both illnesses to varying degrees, but further replication studies are needed to validate these results. There is at present no consensus on specific single nucleotide polymorphisms or halpotypes associated with the particular candidate gene loci in these illnesses. The genetic architecture of glutamate systems in bipolar disorder need to be better studied in view of recent data suggesting an overlap in the genetic aetiology of SZ and BD. There is a pressing need to integrate research platforms in genomics, epistatic models, proteomics, metabolomics, neuroimaging technology and translational studies in order to allow a more integrated understanding of glutamate and GABAergic signalling processes and aberrations in SZ and BD as well as their relationships with clinical presentations and treatment progress over time. [Copyright &y& Elsevier]

Abstract: Biodistribution of gold nanoparticles (AuNPs) in more than 25 organs were examined on 1 day, 1 week, 1 month and 2 months after a single intravenous (i.v.) injection in rats. Au was rapidly and consistently accumulated in liver (49.4±50.4–72.2±40.5ng/g) and spleen (8.4±5.0–9.5±6.4ng/g) throughout the entire timeframe of the study (2 months). Significant accumulation of Au in kidney (up to 5.5±2.5ng/g) and testis (up to 0.6±0.1ng/g) occurred from 1 month post-injection when Au level in urine and feces decreased. Significant increase of Au in blood occurred 2 months after injection, coincident with the delayed accumulation in kidney. Au accumulation in lungs was found at 1 day post-injection but decreased within a week. No accumulation of Au was found in the brain. Microarray results of liver and spleen point to significant effects on genes related to detoxification, lipid metabolism, cell cycle, defense response, and circadian rhythm. These results demonstrate that significant biodistribution of Au occurs in the body over 2 months after a single i.v. injection of AuNPs, accompanied by gene expression changes in target organs. [Copyright &y& Elsevier]

Abstract: Apolipoprotein D (apoD), a member of the lipocalin family of transporter proteins binds a number of small lipophilic molecules including arachidonic acid and cholesterol. Recent studies showed a protective function of mammalian apoD as well as its insect and plant homologs against oxidative stress. In this study we investigated the effect of direct addition of exogenous human apoD protein purified from breast cystic fluid to rat hippocampal slice cultures after excitotoxic injury induced by the glutamate analog kainate. ApoD at a concentration of 10μg/ml partially prevented loss of MAP2 immunostaining and LDH release from injured hippocampal neurons after kainate injury. ApoD also attenuated the increase in oxidative products of arachidonic acid and cholesterol, F2-isoprostanes and 7-ketocholesterol, respectively, after kainate treatment. In view of the molecular structure of apoD which consists of an eight stranded β barrel that forms a binding pocket for a number of small hydrophobic molecules, we propose that apoD promotes its neuroprotective effects by binding to arachidonic acid and cholesterol thus preventing their oxidation to neurotoxic products such as 4-hydroxynonenal (4-HNE) and 7-ketocholesterol. [Copyright &y& Elsevier]

Abstract: A library of functionalized 6-chloro-2-methoxy-(N 9-substituted)acridin-9-amines structurally related to quinacrine were synthesized and evaluated for antiprion activity on four different cell models persistently infected with scrapie prion strains (ScN2a, N167, Ch2) or a human disease prion strain (F3). Most of the compounds were distinguished by the side chain attached to 9-amino of the acridine ring. These were dialkylaminoalkyl and phenyl with basic groups on the phenyl ring. The most promising compound was 6-chloro-2-methoxy-N-(4-(4-methylpiperazin-1-yl)phenyl)acridin-9-amine (15) which had submicromolar EC50 values (0.1–0.7μM) on all cell models, was able to clear PrPSc at non-toxic concentrations of 1.2–2.5μM, and was more active than quinacrine in terms of EC50 values. Other promising compounds were 14 (a regioisomer of 15) and 17 which had a 1-benzylpiperidin-4-yl substituent attached to the 9-amino function. Activity was strongly dependent on the presence of a substituted acridine ring, which in this library comprised 6-chloro-2-methoxy substituents on the acridine ring. The side chains of 14, 15, and 17 have not been previously associated with antiprion activity and are interesting leads for further optimization of antiprion activity. [Copyright &y& Elsevier]

Abstract: Several epidemiological studies have suggested that increased iron stores are associated with increased atherosclerotic events. In order to test the hypothesis that decreasing the vascular level of iron slows lesion growth, we examined the effects of the iron chelator Desferal (72 mg/kg/day, 5 days/week) on atherosclerosis and lesion iron content in cholesterol-fed New Zealand White rabbits. Rabbits were fed with a 1% w/w cholesterol diet for either 8 weeks (and for the last 5 weeks injected daily with Desferal) or 12 weeks (and for the last 9 weeks injected with Desferal). Controls were injected with saline. A significant reduction in average lesion area (p = 0.038) was observed in the 12-week treated animals compared with the 12-week controls. The average lesion iron level of the 12-week treated animals (58 ppm dry wt) was also significantly lower (p = 0.030) than in 12-week control animals (95 ppm dry wt), as measured using nuclear microscopy with the combination of scanning transmission ion microscopy, Rutherford back-scattering spectroscopy, and particle-induced X-ray emission. No reduction in lesion area or iron content was observed in the 8-week treated animals compared with controls, and no change in lesion zinc concentration was observed for either group. Our data strengthen the concept that iron contributes to the early stages of the development of atherosclerosis. [Copyright &y& Elsevier]

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid which modulates vascular integrity through its receptors, S1P 1 –S1P 5. Notably, S1P 2 has been shown to mediate the disruption of cerebrovascular integrity in vitro and in vivo. However, the mechanism underlying this process has not been fully elucidated. We evaluated the role of S1P 2 in blood-brain barrier (BBB) disruption induced by lipopolysaccharide (LPS)-mediated systemic inflammation and found that BBB disruption and neutrophil infiltration were significantly attenuated in S1pr2 −/− mice relative to S1pr2 +/− littermates. This is concomitant with attenuation of LPS-induced transcriptional activation of IL-6 and downregulation of occludin. Furthermore, S1pr2 −/− mice had significantly reduced expression of genes essential for neutrophil infiltration: Sele , Cxcl1 , and Cxcl2. Conversely, pharmacological agonism of S1P 2 induced transcriptional activation of E-selectin in vitro and in vivo. Although S1P 2 does not appear to be required for activation of microglia, stimulation of microglial cells with the S1P 2 potentiated the response of endothelial cells to LPS. These results demonstrate that S1P 2 promotes LPS-induced neutrophil extravasation by inducing expression of endothelial adhesion molecule gene, Sele , and potentiating microglial inflammation of endothelial cells. It is likely that S1P 2 is a mediator of cerebrovascular inflammation and represents a potential therapeutic target for neurodegenerative disease such as vascular cognitive impairment. [Display omitted] • Blood-brain barrier (BBB) disruption is a hallmark of Alzheimer's disease (AD). • Processes that regulate BBB integrity are incompletely characterized. • There are no known interventions to improve BBB function in AD. • S1P 2 mediates inflammatory loss of BBB integrity and leukocyte infiltration. • This is likely due to induction of E-selectin and chemokines in endothelial cells. [ABSTRACT FROM AUTHOR]

Sphingolipids (SPs) are structurally diverse and represent one of the most quantitatively abundant classes of lipids in mammalian cells. In addition to their structural roles, many SP species are known to be bioactive mediators of essential cellular processes. Historically, studies have focused on SP species that contain the canonical 18‑carbon, mono-unsaturated sphingoid backbone. However, increasingly sensitive analytical technologies, driven by advances in mass spectrometry, have facilitated the identification of previously under-appreciated, molecularly distinct SP species. Many of these less abundant species contain noncanonical backbones. Interestingly, a growing number of studies have identified clinical associations between these noncanonical SPs and disease, suggesting that there is functional significance to the alteration of SP backbone structure. For example, associations have been found between SP chain length and cardiovascular disease, pain, diabetes, and dementia. This review will provide an overview of the processes that are known to regulate noncanonical SP accumulation, describe the clinical correlations reported for these molecules, and review the experimental evidence for the potential functional implications of their dysregulation. It is likely that further scrutiny of noncanonical SPs may provide new insight into pathophysiological processes, serve as useful biomarkers for disease, and lead to the design of novel therapeutic strategies. [ABSTRACT FROM AUTHOR]

Abstract: High levels of calcium-independent phospholipase A2 (iPLA2) are present in the striatum and cerebral cortex [W.Y. Ong, J.F. Yeo, S.F. Ling, A.A. Farooqui, Distribution of calcium-independent phospholipase A2 (iPLA2) in monkey brain, J. Neurocytol. 34 (2005) 447–458], and several clinical investigations have suggested a possible role of altered iPLA2 activity in neurodegenerative and psychiatric disorders. The present study was carried out to elucidate a possible effect of PLA2 on prepulse inhibition (PPI) of the acoustic startle reflex. Rats that received intraperitoneal injection of the non-specific PLA2 inhibitor, quinacrine, showed significantly decreased PPI at 76, 80, and 84dB, compared to saline injected controls. In addition, rats that received intrastriatal injection of antisense oligonucleotide to iPLA2 showed significant reduction in PPI at prepulse intensities of 76 and 84dB compared to scrambled sense injected controls. Together, these findings point to a role of PLA2 in PPI of the auditory startle reflex and sensorimotor gating. [Copyright &y& Elsevier]