African-American and Caucasian participation in postmortem human brain donation for neuropsychiatric research.

Increased African-American research participation is critical to the applicability and generalizability of biomedical research, as population diversity continues to increase both domestically and abroad. Yet numerous studies document historical origins of mistrust, as well as other barriers that may contribute to resistance in the African-American community towards participation in biomedical research. However, a growing body of more recent scientific evidence suggests that African-Americans value research and are willing to participate when asked.

Early-life decline in neurogenesis markers and age-related changes of TrkB splice variant expression in the human subependymal zone.

Neurogenesis in the subependymal zone (SEZ) declines across the human lifespan, and reduced local neurotrophic support is speculated to be a contributing factor. While tyrosine receptor kinase B (TrkB) signalling is critical for neuronal differentiation, maturation and survival, little is known about subependymal TrkB expression changes during postnatal human life. In this study, we used quantitative PCR and in situ hybridisation to determine expression of the cell proliferation marker Ki67, the immature neuron marker doublecortin (DCX) and both full-length (TrkB-TK+) and truncated TrkB receptors (TrkB-TK-) in the human SEZ from infancy to middle age (n = 26-35, 41 days to 43 years).

Cortical Transcriptional Profiles in APOE4 Carriers with Alzheimer's Disease: Patterns of Protection and Degeneration.

Transcriptional profiling of postmortem Alzheimer's disease (AD) brain tissue has yielded important insights into disease. We recently described a novel approach to understand transcriptional changes in AD designed to identify both neuro-susceptibility and intrinsic neuroprotective factors in young non-AD E4 carriers. Here we extend our work to APOE4 related AD itself.

The human brain and face: mechanisms of cranial, neurological and facial development revealed through malformations of holoprosencephaly, cyclopia and aberrations in chromosome 18.

The study of inborn genetic errors can lend insight into mechanisms of normal human development and congenital malformations. Here, we present the first detailed comparison of cranial and neuro pathology in two exceedingly rare human individuals with cyclopia and alobar holoprosencephaly (HPE) in the presence and absence of aberrant chromosome 18 (aCh18). The aCh18 fetus contained one normal Ch18 and one with a pseudo-isodicentric duplication of chromosome 18q and partial deletion of 18p from 18p11.

Transcript-specific associations of SLC12A5 (KCC2) in human prefrontal cortex with development, schizophrenia, and affective disorders.

The neuron-specific K(+)-Cl(-) cotransporter SLC12A5, also known as KCC2, helps mediate the electrophysiological effects of GABA. The pattern of KCC2 expression during early brain development suggests that its upregulation drives the postsynaptic switch of GABA from excitation to inhibition. We previously found decreased expression of full-length KCC2 in the postmortem hippocampus of patients with schizophrenia, but not in the dorsolateral prefrontal cortex (DLPFC).

Opposing effects of pigment epithelium-derived factor on breast cancer cell versus neuronal survival: implication for brain metastasis and metastasis-induced brain damage.

Brain metastases are a significant cause of morbidity and mortality for patients with cancer, yet preventative and therapeutic options remain an unmet need. The cytokine pigment epithelium-derived factor (PEDF) is downregulated in resected human brain metastases of breast cancer compared with primary breast tumors, suggesting that restoring its expression might limit metastatic spread. Here, we show that outgrowth of large experimental brain metastases from human 231-BR or murine 4T1-BR breast cancer cells was suppressed by PEDF expression, as supported by in vitro analyses as well as direct intracranial implantation.

Temporal dynamics and genetic control of transcription in the human prefrontal cortex.

Previous investigations have combined transcriptional and genetic analyses in human cell lines, but few have applied these techniques to human neural tissue. To gain a global molecular perspective on the role of the human genome in cortical development, function and ageing, we explore the temporal dynamics and genetic control of transcription in human prefrontal cortex in an extensive series of post-mortem brains from fetal development through ageing. We discover a wave of gene expression changes occurring during fetal development which are reversed in early postnatal life.

Expression of GABA signaling molecules KCC2, NKCC1, and GAD1 in cortical development and schizophrenia.

GABA signaling molecules are critical for both human brain development and the pathophysiology of schizophrenia. We examined the expression of transcripts derived from three genes related to GABA signaling [GAD1 (GAD67 and GAD25), SLC12A2 (NKCC1), and SLC12A5 (KCC2)] in the prefrontal cortex (PFC) and hippocampal formation of a large cohort of nonpsychiatric control human brains (n = 240) across the lifespan (from fetal week 14 to 80 years) and in patients with schizophrenia (n = 30-31), using quantitative RT-PCR. We also examined whether a schizophrenia risk-associated promoter SNP in GAD1 (rs3749034) is related to expression of these transcripts.

Evaluation of tissue collection for postmortem studies of bipolar disorder.

Objectives: Postmortem human brain is a valuable resource for studying the neuropathology, neurochemistry, and molecular pathways of genes associated with bipolar disorder (BPD), yet available, well-characterized BPD brain tissue appears scarce. We set out to evaluate BPD postmortem brain collections in order to identify both successful methods as well as barriers to collection.

Methods: We conducted a literature review of postmortem studies of BPD over the past 30 years, compared and contrasted characteristics of established BPD collections, and identified possible barriers specific to BPD brain collection based on our experience at the NIMH Brain Collection.

Metabotropic glutamate receptor 2 and 3 gene expression in the human prefrontal cortex and mesencephalon in schizophrenia.

Group II metabotropic glutamate receptors (mGluR2 and mGluR3) are implicated in schizophrenia. We characterized mGluR2 and 3 mRNA in the human prefrontal cortex (PFC) and mesencephalon, and then compared cases with schizophrenia to matched controls. In the human brain, both receptors were expressed in the PFC and, unlike the rodent, in dopaminergic (DA) cell groups.

Age-related changes in the expression of schizophrenia susceptibility genes in the human prefrontal cortex.

The molecular basis of complex neuropsychiatric disorders most likely involves many genes. In recent years, specific genetic variations influencing risk for schizophrenia and other neuropsychiatric disorders have been reported. We have used custom DNA microarrays and qPCR to investigate the expression of putative schizophrenia susceptibility genes and related genes of interest in the normal human brain.

Postmortem diagnosis and toxicological validation of illicit substance use.

The present study examines the diagnostic challenges of identifying ante-mortem illicit substance use in human postmortem cases. Substance use, assessed by clinical case history reviews, structured next-of-kin interviews, by general toxicology of blood, urine and/or brain, and by scalp hair testing, identified 33 cocaine, 29 cannabis, 10 phencyclidine and nine opioid cases. Case history identified 42% cocaine, 76% cannabis, 10% phencyclidine and 33% opioid cases.

Increased lactate levels and reduced pH in postmortem brains of schizophrenics: medication confounds.

A number of postmortem studies have found decreased pH in brains of patients with schizophrenia. Insofar as lower pH has been associated with decreased mRNA expression in postmortem human brain, decreased pH in schizophrenia may represent an important potential confound in comparisons between patients and controls. We hypothesized that decreased pH may be related to increased concentration of lactic acid.

Synthesis and evaluation of N-methyl and S-methyl 11C-labeled 6-methylthio-2-(4'-N,N-dimethylamino)phenylimidazo[1,2-a]pyridines as radioligands for imaging beta-amyloid plaques in Alzheimer's disease.

6-Thiolato-substituted 2-(4'- N,N-dimethylamino)phenylimidazo[1,2- a]pyridines ( RS-IMPYs; 1- 4) were synthesized as candidates for labeling with carbon-11 ( t 1/2 = 20.4 min) and imaging of A beta plaques in living human brain using positron emission tomography (PET). K i values for binding of these ligands to Alzheimer's disease brain homogenates were measured in vitro against tritium-labeled 6 (Pittsburgh compound B).

Synthesis and structure-affinity relationships of new 4-(6-iodo-H-imidazo[1,2-a]pyridin-2-yl)-N-dimethylbenzeneamine derivatives as ligands for human beta-amyloid plaques.

A new and extensive set of 4-(6-iodo-H-imidazo[1,2-a]pyridin-2-yl)-N-dimethylbenzeneamine (IMPY) derivatives was synthesized and assayed for affinity toward human Abeta plaques. 6-Ethylthio- (12h), 6-cyano- (12e), 6-nitro- (12f), and 6-p-methoxybenzylthio- (15d) analogues were discovered to have high affinity (KI < 10 nM). However, introduction of a hydrophilic thioether group in the 6-position (15a-c, 15e-g) reduced or abolished affinity.

Mechanisms of aluminum-induced neurodegeneration in animals: Implications for Alzheimer's disease.

For four decades the controversial question concerning a possible role for aluminum neurotoxicity in contributing to the pathogenesis of Alzheimer's disease has been debated, and studies by different investigators have yielded contradictory results. The lack of sensitivity to aluminum neurotoxicity in transgenic mouse models of Alzheimer's disease has not allowed the system to be used to explore important aspects of this toxicity. Rabbits are particularly sensitive to aluminum neurotoxicity and they develop severe neurological changes that are dependent on dose, age and route of administration.

Critical factors in gene expression in postmortem human brain: Focus on studies in schizophrenia.

Background: Studies of postmortem human brain are important for investigating underlying pathogenic molecular mechanisms of neuropsychiatric disorders. They are, however, confounded by pre- and postmortem factors. The purpose of this study was to identify sources of variation that will enable a better design of gene expression studies and higher reliability of gene expression data.

Synaptophysin protein and mRNA expression in the human hippocampal formation from birth to old age.

In the human neocortex, progressive synaptogenesis in early postnatal life is followed by a decline in synaptic density, then stability from adolescence until middle age. No comparable data are available in the hippocampus. In this study, the integral synaptic vesicle protein synaptophysin, measured immunoautoradiographically, was used as an index of synaptic terminal abundance in the hippocampal formation of 37 subjects from 5 weeks to 86 yr old, divided into 4 age groups (10 infants, 15 adolescents/young adults, 6 adults, and 6 elderly).

High cholesterol content in neurons increases BACE, beta-amyloid, and phosphorylated tau levels in rabbit hippocampus.

Epidemiological, cellular, and animal studies suggest that abnormalities in cholesterol metabolism may contribute to the etiology of Alzheimer's disease by increasing the generation of beta-amyloid (Abeta). However, the mechanism by which cholesterol increases Abeta levels is not fully understood. In the present study, we demonstrate that feeding rabbits with 1% cholesterol for 7 months causes an increase in cholesterol content in neurons.

Age-related differences in glucocorticoid receptor mRNA levels in the human brain.

Glucocorticoids and their receptors (GRs) are implicated in dynamic cognitive and neuroendocrine processes mediated by the prefrontal cortex and hippocampus. Additionally, a primary defect in forebrain GR levels can mimic symptoms of depression. We hypothesized that changes in GR mRNA levels may occur in the human brain across the life span thus positioning GR to differentially influence behavior and disease susceptibility.

Expression of DISC1 binding partners is reduced in schizophrenia and associated with DISC1 SNPs.

DISC1 has been identified as a schizophrenia susceptibility gene based on linkage and SNP association studies and clinical data suggesting that risk SNPs impact on hippocampal structure and function. In cell and animal models, C-terminus-truncated DISC1 disrupts intracellular transport, neural architecture and migration, perhaps because it fails to interact with binding partners involved in neuronal differentiation such as fasciculation and elongation protein zeta-1 (FEZ1), platelet-activating factor acetylhydrolase, isoform Ib, PAFAH1B1 or lissencephaly 1 protein (LIS1) and nuclear distribution element-like (NUDEL). We hypothesized that altered expression of DISC1 and/or its molecular partners may underlie its pathogenic role in schizophrenia and explain its genetic association.

A validated positive chemical ionization GC/MS method for the identification and quantification of amphetamine, opiates, cocaine, and metabolites in human postmortem brain.

A sensitive and specific method for the simultaneous detection and quantification of amphetamine, opiates, and cocaine and metabolites in human postmortem brain was developed and validated. Analytes of interest included amphetamine, morphine, codeine, 6-acetylmorphine, cocaine, benzoylecgonine, ecgonine methyl ester, ecgonine ethyl ester, cocaethylene, and anhydroecgonine methyl ester. The method employed ultrasonic homogenization of brain tissue in pH 4.

Reduced density of cholinergic interneurons in the ventral striatum in schizophrenia: an in situ hybridization study.

Background: The role of the striatum in the pathophysiology of schizophrenia is not understood. In a previous postmortem study, we found a reduction in the density of striatal interneurons that stain immunohistochemically for choline acetyltransferase (ChAT) in schizophrenia.

Methods: To determine whether this finding represents a specific alteration in ChAT gene expression, we used in situ hybridization to study the striatum of 11 control and 9 schizophrenic subjects with oligonucleotide probes complementary to human ChAT mRNA, preprosomatostatin (PPS) mRNA, and beta-actin mRNA.