Id4 and FABP7 are preferentially expressed in cells with astrocytic features in oligodendrogliomas and oligoastrocytomas

BACKGROUND: Oligodendroglioma (ODG) and oligoastrocytoma (OAC) are diffusely infiltrating primary brain tumors whose pathogenesis remains unclear. We previously identified a group of genes whose expression was inversely correlated with survival in a cohort of patients with glioblastoma (GBM), and some of these genes are also reportedly expressed in ODG and OAC. We examined the expression patterns and localization of these survival-associated genes in ODG and OAC in order to analyze their possible roles in the oncogenesis of these two tumor types. METHODS: We used UniGene libraries derived from GBM and ODG specimens to examine the expression levels of the transcripts for each of the 50 GBM survival-associated genes. We used immunohistochemistry and cDNA microarrays to examine expression of selected survival-associated genes and Id4, a gene believed to control the timing of oligodendrocyte development. The expression of FABP7 and Id4 and the survival of patients with ODG and OAC were also analyzed. RESULTS: Transcripts of most survival-associated genes as well as Id4 were present in both GBM and ODG tumors, whereas protein expression of Id4 and one of the survival-associated genes, brain-type fatty acid-binding protein (FABP7), was present in cells with astrocytic features, including reactive and neoplastic astrocytes, but not in neoplastic oligodendrocytes. Id4 was co-expressed with FABP7 in microgemistocytes in ODG and in neoplastic astrocytes in OAC. Id4 and FABP7 expression, however, did not correlate with the clinical outcome of patients with ODG or OAC tumors. CONCLUSION: Expression of Id4 and some of our previously identified GBM survival-associated genes is present in developing or mature oligodendrocytes. However, protein expression of Id4 and FABP7 in GBM, ODG, and OAC suggests that this group of functionally important genes might demonstrate two patterns of expression in these glioma subtypes: one group is universally expressed in glioma cells, and the other group of genes is expressed primarily in neoplastic astrocytes but not in neoplastic oligodendrocytes. Differential protein expression of these two groups of genes in ODG and OAC may be related to the cellular origins and the histological features of the neoplastic cells

Genome wide association for substance dependence: convergent results from epidemiologic and research volunteer samples

<p>Abstract</p> <p>Background</p> <p>Dependences on addictive substances are substantially-heritable complex disorders whose molecular genetic bases have been partially elucidated by studies that have largely focused on research volunteers, including those recruited in Baltimore. Maryland. Subjects recruited from the Baltimore site of the Epidemiological Catchment Area (ECA) study provide a potentially-useful comparison group for possible confounding features that might arise from selecting research volunteer samples of substance dependent and control individuals. We now report novel SNP (single nucleotide polymorphism) genome wide association (GWA) results for vulnerability to substance dependence in ECA participants, who were initially ascertained as members of a probability sample from Baltimore, and compare the results to those from ethnically-matched Baltimore research volunteers.</p> <p>Results</p> <p>We identify substantial overlap between the home address zip codes reported by members of these two samples. We find overlapping clusters of SNPs whose allele frequencies differ with nominal significance between substance dependent <it>vs </it>control individuals in both samples. These overlapping clusters of nominally-positive SNPs identify 172 genes in ways that are never found by chance in Monte Carlo simulation studies. Comparison with data from human expressed sequence tags suggests that these genes are expressed in brain, especially in hippocampus and amygdala, to extents that are greater than chance.</p> <p>Conclusion</p> <p>The convergent results from these probability sample and research volunteer sample datasets support prior genome wide association results. They fail to support the idea that large portions of the molecular genetic results for vulnerability to substance dependence derive from factors that are limited to research volunteers.</p

Genomic Regions Identified by Overlapping Clusters of Nominally-Positive SNPs from Genome-Wide Studies of Alcohol and Illegal Substance Dependence

Declaring “replication” from results of genome wide association (GWA) studies is straightforward when major gene effects provide genome-wide significance for association of the same allele of the same SNP in each of multiple independent samples. However, such unambiguous replication is unlikely when phenotypes display polygenic genetic architecture, allelic heterogeneity, locus heterogeneity and when different samples display linkage disequilibria with different fine structures. We seek chromosomal regions that are tagged by clustered SNPs that display nominally-significant association in each of several independent samples. This approach provides one “nontemplate” approach to identifying overall replication of groups of GWA results in the face of difficult genetic architectures. We apply this strategy to 1 M SNP GWA results for dependence on: a) alcohol (including many individuals with dependence on other addictive substances) and b) at least one illegal substance (including many individuals dependent on alcohol). This approach provides high confidence in rejecting the null hypothesis that chance alone accounts for the extent to which clustered, nominally-significant SNPs from samples of the same racial/ethnic background identify the same sets of chromosomal regions. It identifies several genes that are also reported in other independent alcohol-dependence GWA datasets. There is more modest confidence in: a) identification of individual chromosomal regions and genes that are not also identified by data from other independent samples, b) the more modest overlap between results from samples of different racial/ethnic backgrounds and c) the extent to which any gene not identified herein is excluded, since the power of each of these individual samples is modest. Nevertheless, the strong overlap identified among the samples with similar racial/ethnic backgrounds supports contributions to individual differences in vulnerability to addictions that come from newer allelic variants that are common in subsets of current humans

First Neutrino Observations from the Sudbury Neutrino Observatory

The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed.Comment: Latex, 7 pages, 10 figures, Invited paper at Neutrino 2000 Conference, Sudbury, Canada, June 16-21, 2000 to be published in the Proceeding

Mapping alterations to the endogenous elemental distribution within the lateral ventricles and choroid plexus in brain disorders using X-ray fluorescence imaging

The choroid plexus and cerebral ventricles are critical structures for the production of cerebral spinal fluid (CSF) and play an important role in regulating ion and metal transport in the brain, however many aspects of its roles in normal physiology and disease states, such as psychiatric illness, remain unknown. The choroid plexus is difficult to examine in vivo, and in situ ex vivo, and as such has typically been examined indirectly with radiolabeled tracers or ex vivo stains, making measurements of the endogenous K+, Cl-, and Ca+ distributions unreliable. In the present study, we directly examined the distribution of endogenous ions and biologically relevant transition metals in the choroid plexus and regions surrounding the ventricles (ventricle wall, cortex, corpus callosum, striatum) using X-ray fluorescence imaging (XFI). We find that the choroid plexus was rich in Cl- and Fe while K+ levels increase further from the ventricle as Cl- levels decrease, consistent with the known role of ion transporters in the choroid plexus CSF production. A polyI:C offspring displayed enlarged ventricles, elevated Cl- surrounding the ventricles, and intraventricular calcifications. These observations fit with clinical findings in patients with schizophrenia and suggest maternal treatment with polyI:C may lead to dysfunctional ion regulation in offspring. This study demonstrates the power of XFI for examining the endogenous elemental distributions of the ventricular system in healthy brain tissue as well as disease models

Methods to Quantify Nanomaterial Association with, and Distribution across, the Blood-Brain Barrier in Vivo

The role and functional anatomy of the blood-brain barrier (BBB) is summarized to enable the investigator to appropriately address evaluation of nanomaterial interaction with, and distribution across, it into brain tissue (parenchyma). Transport mechanisms across the BBB are presented, in relation to nanomaterial physicochemical properties. Measures and test substances to assess BBB integrity/disruption/permeation are introduced, along with how they are used to interpret the results obtained with the presented methods. Experimental pitfalls and misinterpretation of results of studies of brain nanomaterial uptake are briefly summarized, that can be avoided with the methods presented in this chapter. Two methods are presented. The in situ brain perfusion technique is used to determine rate and extent of nanomaterial distribution into the brain. The capillary depletion method separates brain parenchymal tissue from the endothelial cells that contribute to the BBB. It is used to verify nanomaterial brain tissue entry. These methods are best used together, the latter refining the results obtained with the former. Details of the materials and equipment needed to conduct these methods, and description of the procedures and data interpretation, are provided

Molecular genetics of nicotine dependence and abstinence: whole genome association using 520,000 SNPs

BACKGROUND: Classical genetic studies indicate that nicotine dependence is a substantially heritable complex disorder. Genetic vulnerabilities to nicotine dependence largely overlap with genetic vulnerabilities to dependence on other addictive substances. Successful abstinence from nicotine displays substantial heritable components as well. Some of the heritability for the ability to quit smoking appears to overlap with the genetics of nicotine dependence and some does not. We now report genome wide association studies of nicotine dependent individuals who were successful in abstaining from cigarette smoking, nicotine dependent individuals who were not successful in abstaining and ethnically-matched control subjects free from substantial lifetime use of any addictive substance. RESULTS: These data, and their comparison with data that we have previously obtained from comparisons of four other substance dependent vs control samples support two main ideas: 1) Single nucleotide polymorphisms (SNPs) whose allele frequencies distinguish nicotine-dependent from control individuals identify a set of genes that overlaps significantly with the set of genes that contain markers whose allelic frequencies distinguish the four other substance dependent vs control groups (p < 0.018). 2) SNPs whose allelic frequencies distinguish successful vs unsuccessful abstainers cluster in small genomic regions in ways that are highly unlikely to be due to chance (Monte Carlo p < 0.00001). CONCLUSION: These clustered SNPs nominate candidate genes for successful abstinence from smoking that are implicated in interesting functions: cell adhesion, enzymes, transcriptional regulators, neurotransmitters and receptors and regulation of DNA, RNA and proteins. As these observations are replicated, they will provide an increasingly-strong basis for understanding mechanisms of successful abstinence, for identifying individuals more or less likely to succeed in smoking cessation efforts and for tailoring therapies so that genotypes can help match smokers with the treatments that are most likely to benefit them

Pharmacological Characterization of [3H]CHIBA-3007 Binding to Glycine Transporter 1 in the Rat Brain

Glycine transporter-1 (GlyT-1) in glial cells regulates extracellular levels of glycine, which acts as an obligatory co-agonist at the N-methyl-D-aspartate (NMDA) receptors in the brain. In the present study, we developed a novel radioligand, [3H]3-chloro-N-((S)-((R)-1-methylpiperidin-2-yl)(thiophen- 3-yl)methyl)-4- (trifluoromethyl)picolinamide ([3H]CHIBA-3007), for studying GlyT-1 in the brain. The presence of a single saturable high-affinity binding component for [3H]CHIBA-3007 binding to the rat brain membranes was detected. Scatchard analysis revealed an apparent equilibrium dissociation constant (Kd) of 1.61±0.16 nM and a maximal number of binding sites (Bmax) of 692.8±22.8 fmol/mg protein (mean ± SEM, n = 3). The specific binding of [3H]CHIBA-3007 was inhibited by a number of GlyT-1 inhibitors, such as CHIBA-3007, desmethyl-CHIBA-3007, CHIBA-3008, SSR504734, NFPS/ALX5407, LY2365109 and Org24598, consistent with the pharmacological profiles of GlyT-1 inhibitors. Interestingly, the potency of eight GlyT-1 inhibitors (CHIBA-3007, desmethyl-CHIBA-3007, NFPS/ALX5407, LY2365109, Org24598, SSR504734, sarcosine, and glycine) for blocking in vitro specific binding of [3H]CHIBA-3007 was significantly correlated with the potency of these inhibitors for inhibiting [14C]glycine uptake in the rat brain membranes. In contrast, the GlyT-2 inhibitor ALX1393 exhibited very weak for [3H]CHIBA-3007 binding. Furthermore, the regional distribution of [3H]CHIBA-3007 binding in the rat brain was similar to the previously reported distribution of GlyT-1. The present findings suggest that [3H]CHIBA-3007 would be a useful new radioligand for studying GlyT-1 in the brain