RESUMEN
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). We further measured TrkB-TK+ and TrkB-TK- mRNAs in the SEZ from young adulthood into ageing (n = 50, 21-103 years), and related their transcript levels to neurogenic and glial cell markers. Ki67, DCX and both TrkB splice variant mRNAs significantly decreased in the SEZ from infancy to middle age. In contrast, TrkB-TK- mRNA increased in the SEZ from young adulthood into ageing, whereas TrkB-TK+ mRNA remained stable. TrkB-TK- mRNA positively correlated with expression of neural precursor (glial fibrillary acidic protein delta and achaete-scute homolog 1) and glial cell markers (vimentin and pan glial fibrillary acidic protein). TrkB-TK+ mRNA positively correlated with expression of neuronal cell markers (DCX and tubulin beta 3 class III). Our results indicate that cells residing in the human SEZ maintain their responsiveness to neurotrophins; however, this capability may change across postnatal life. We suggest that TrkB splice variants may differentially influence neuronal and glial differentiation in the human SEZ.
Asunto(s)
Envejecimiento/metabolismo , Ventrículos Laterales/crecimiento & desarrollo , Ventrículos Laterales/metabolismo , Glicoproteínas de Membrana/metabolismo , Neurogénesis/fisiología , Receptor trkB/metabolismo , Nicho de Células Madre/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Núcleo Caudado/crecimiento & desarrollo , Núcleo Caudado/metabolismo , Estudios de Cohortes , Proteínas de Dominio Doblecortina , Proteína Doblecortina , Femenino , Humanos , Lactante , Antígeno Ki-67/metabolismo , Masculino , Proteínas Asociadas a Microtúbulos/metabolismo , Persona de Mediana Edad , Neuropéptidos/metabolismo , Isoformas de Proteínas , ARN Mensajero/metabolismo , Adulto JovenRESUMEN
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. One half-century later in life, this pattern of reversals is mirrored in ageing and in neurodegeneration. Although we identify thousands of robust associations of individual genetic polymorphisms with gene expression, we also demonstrate that there is no association between the total extent of genetic differences between subjects and the global similarity of their transcriptional profiles. Hence, the human genome produces a consistent molecular architecture in the prefrontal cortex, despite millions of genetic differences across individuals and races. To enable further discovery, this entire data set is freely available (from Gene Expression Omnibus: accession GSE30272; and dbGaP: accession phs000417.v1.p1) and can also be interrogated via a biologist-friendly stand-alone application (http://www.libd.org/braincloud).
Asunto(s)
Envejecimiento/genética , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica/genética , Corteza Prefrontal/crecimiento & desarrollo , Corteza Prefrontal/metabolismo , Transcriptoma/genética , Autopsia , Feto/metabolismo , Genoma Humano/genética , Humanos , Polimorfismo de Nucleótido Simple/genética , Corteza Prefrontal/embriología , Grupos Raciales/genética , Factores de TiempoRESUMEN
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 18p11.31 where the HPE gene, TGIF, resides, to the p terminus. In addition to synophthalmia, the aCh18 cyclopic malformations included a failure of induction of most of the telencephalon - closely approximating anencephaly, unchecked development of brain stem structures, near absence of the sphenoid bone and a malformed neurocranium and viscerocranium that constitute the median face. Although there was complete erasure of the olfactory and superior nasal structures, rudiments of nasal structures derived from the maxillary bone were evident, but with absent pharyngeal structures. The second non-aCh18 cyclopic fetus was initially classified as a true Cyclops, as it appeared to have a proboscis and one median eye with a single iris, but further analysis revealed two eye globes as expected for synophthalmic cyclopia. Furthermore, the proboscis was associated with the medial ethmoid ridge, consistent with an incomplete induction of these nasal structures, even as the nasal septum and paranasal sinuses were apparently developed. An important conclusion of this study is that it is the brain that predicts the overall configuration of the face, due to its influence on the development of surrounding skeletal structures. The present data using a combination of macroscopic, computed tomography (CT) and magnetic resonance imaging (MRI) techniques provide an unparalleled analysis on the extent of the effects of median defects, and insight into normal development and patterning of the brain, face and their skeletal support.
Asunto(s)
Encéfalo/embriología , Aberraciones Cromosómicas , Cromosomas Humanos Par 18 , Cara/embriología , Holoprosencefalia , Cadáver , Edad Gestacional , Holoprosencefalia/embriología , Holoprosencefalia/genética , Humanos , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos XRESUMEN
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). Using PCR and rapid amplification of cDNA ends, we discovered several previously unrecognized alternative KCC2 transcripts in both human adult and fetal brain in addition to the previously identified full-length (NM_020708.3) and truncated (AK098371) transcripts. We measured the expression levels of four relatively abundant truncated splice variants, including three novel transcripts (ΔEXON6, EXON2B, and EXON6B) and one previously described transcript (AK098371), in a large human cohort of nonpsychiatric controls across the lifespan, and in patients with schizophrenia and affective disorders. In SH-SY5Y cell lines, these transcripts were translated into proteins and expressed at their predicted sizes. Expression of the EXON6B transcript is increased in the DLPFC of patients with schizophrenia (p = 0.03) but decreased in patients with major depression (p = 0.04). The expression of AK098371 is associated with a GAD1 single nucleotide polymorphism (rs3749034) that previously has been associated with GAD67 expression and risk for schizophrenia. Our data confirm the developmental regulation of KCC2 expression, and provide evidence that KCC2 transcripts are differentially expressed in schizophrenia and affective disorders. Alternate transcripts from KCC2 may participate in the abnormal GABA signaling in the DLPFC associated with schizophrenia.
Asunto(s)
Trastornos del Humor/genética , Corteza Prefrontal/crecimiento & desarrollo , Corteza Prefrontal/metabolismo , Esquizofrenia/genética , Simportadores/genética , Adulto , Anciano de 80 o más Años , Trastorno Bipolar/genética , Trastorno Bipolar/metabolismo , Western Blotting , Línea Celular , ADN Complementario/biosíntesis , ADN Complementario/aislamiento & purificación , Trastorno Depresivo Mayor/genética , Trastorno Depresivo Mayor/metabolismo , Exones/genética , Femenino , Amplificación de Genes , Variación Genética/genética , Variación Genética/fisiología , Genotipo , Glutamato Descarboxilasa/genética , Humanos , Masculino , Persona de Mediana Edad , Trastornos del Humor/metabolismo , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , Isoformas de Proteínas/genética , ARN/biosíntesis , ARN/aislamiento & purificación , Esquizofrenia/metabolismo , Simportadores/metabolismo , Transfección , Adulto Joven , Cotransportadores de K ClRESUMEN
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. Our studies revealed that development and maturation of both the PFC and hippocampal formation are characterized by progressive switches in expression from GAD25 to GAD67 and from NKCC1 to KCC2. Previous studies have demonstrated that the former leads to GABA synthesis, and the latter leads to switching from excitatory to inhibitory neurotransmission. In the hippocampal formation, GAD25/GAD67 and NKCC1/KCC2 ratios are increased in patients with schizophrenia, reflecting a potentially immature GABA physiology. Remarkably, GAD25/GAD67 and NKCC1/KCC2 expression ratios are associated with rs3749034 genotype, with risk alleles again predicting a relatively less mature pattern. These findings suggest that abnormalities in GABA signaling critical to brain development contribute to genetic risk for schizophrenia.
Asunto(s)
Corteza Cerebral/embriología , Corteza Cerebral/crecimiento & desarrollo , Corteza Cerebral/metabolismo , Esquizofrenia/patología , Transducción de Señal/fisiología , Ácido gamma-Aminobutírico/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Antipsicóticos/farmacología , Corteza Cerebral/efectos de los fármacos , Niño , Preescolar , Estudios de Cohortes , Femenino , Feto , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Genotipo , Glutamato Descarboxilasa/genética , Glutamato Descarboxilasa/metabolismo , Hipocampo/efectos de los fármacos , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Simportadores de Cloruro de Sodio-Potasio/genética , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Miembro 2 de la Familia de Transportadores de Soluto 12 , Simportadores/genética , Simportadores/metabolismo , Ácido gamma-Aminobutírico/genética , Cotransportadores de K ClRESUMEN
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. In the present study, we set out to determine factors associated with research participation of African-American families in postmortem human brain tissue donation for neuropsychiatric disorders as compared with Caucasian families, from same-day medical examiner autopsy referrals. We retrospectively reviewed brain donation rates, as well as demographic and clinical factors associated with donation in 1,421 consecutive referrals to three medical examiner's offices from 2010-2015. Overall, 69.7% of all next-of-kin contacted agreed to brain donation. While Caucasian families consented to donate brain tissue at a significantly higher rate (74.1%) than African-American families (57.0%) (p<0.001), African-American brain donation rates were as high as 60.5% in referrals from Maryland. Neither African-American nor Caucasian donors differed significantly from non-donors on any demographic or clinical factors ascertained, including age, sex, diagnosis of the donor, or in the relationship of the next-of-kin being contacted (p>0.05). However, Caucasian donors were significantly older, had more years of education, were more likely to be referred for study due to a psychiatric diagnosis, more likely to have comorbid substance abuse, and more likely to have died via suicide, as compared with African-American donors (p<0.05). When African-American participants are identified and approached, African-American families as well as Caucasian families are indeed willing to donate brain tissue on the spot for neuropsychiatric research, which supports the belief that African-American attitudes towards biomedical research may be more favorable than previously thought.
Asunto(s)
Investigación Biomédica , Negro o Afroamericano , Encéfalo/fisiología , Neuropsiquiatría , Cambios Post Mortem , Donantes de Tejidos , Población Blanca , Familia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Derivación y ConsultaRESUMEN
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). MeS-IMPY ( 3, K i = 7.93 nM) was labeled with carbon-11 at its S- or N-methyl position to give [ (11)C] 7 or [ (11)C] 8, respectively. After injection into rats, [ (11)C] 7 or [ (11)C] 8 gave moderately high brain uptakes of radioactivity followed by rapid washout to low levels. The ratio of radioactivity at maximal uptake to that at 60 min reached 18.7 for [ (11)C] 7. [ (11)C] 7 behaved similarly in mouse and monkey. [ (11)C] 7 also bound selectively to A beta plaques in post mortem human Alzheimer's disease brain. Although rapidly metabolized in rat by N-demethylation, [ (11)C] 7 was stable in rat brain homogenates. The ex vivo brain radiometabolites observed in rats have a peripheral origin. Overall, [ (11)C] 7 merits further evaluation in human subjects.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Imidazoles/síntesis química , Piridinas/síntesis química , Radiofármacos/síntesis química , Enfermedad de Alzheimer/diagnóstico por imagen , Animales , Autorradiografía , Encéfalo/diagnóstico por imagen , Radioisótopos de Carbono , Humanos , Imidazoles/química , Imidazoles/farmacocinética , Macaca mulatta , Masculino , Ratones , Tomografía de Emisión de Positrones , Piridinas/química , Piridinas/farmacocinética , Radiofármacos/química , Radiofármacos/farmacocinética , Ratas , Distribución TisularRESUMEN
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. However, in contrast to the previous notion that an increase in lactic acid represents evidence for primary metabolic abnormalities in schizophrenia, we hypothesized that this increase is secondary to prior antipsychotic treatment. We have tested this by first demonstrating that lactate levels in the cerebellum of patients with schizophrenia (n=35) are increased relative to control subjects (n=42) by 28%, p=0.001. Second, we have shown that there is an excellent correlation between lactate levels in the cerebellum and pH, and that this correlation is particularly strong in patients (r=-0.78, p=3E-6). Third, we have shown in rats that chronic haloperidol (0.8mg/kg/day) and clozapine (5mg/kg/day) increase lactic acid concentration in the frontal cortex relative to vehicle (by 31% and 22% respectively, p<0.01). These data suggest that lactate increases in postmortem human brain of patients with schizophrenia are associated with decreased pH and that these changes are possibly related to antipsychotic treatment rather than a primary metabolic abnormality in the prefrontal cortex of patients with schizophrenia.
Asunto(s)
Antipsicóticos/farmacología , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Ácido Láctico/metabolismo , Esquizofrenia/tratamiento farmacológico , Esquizofrenia/metabolismo , Animales , Artefactos , Encéfalo/fisiopatología , Química Encefálica/efectos de los fármacos , Química Encefálica/fisiología , Encefalopatías Metabólicas/inducido químicamente , Encefalopatías Metabólicas/metabolismo , Encefalopatías Metabólicas/fisiopatología , Cerebelo/efectos de los fármacos , Cerebelo/metabolismo , Cerebelo/fisiopatología , Clozapina/farmacología , Factores de Confusión Epidemiológicos , Metabolismo Energético/efectos de los fármacos , Metabolismo Energético/fisiología , Haloperidol/farmacología , Humanos , Concentración de Iones de Hidrógeno/efectos de los fármacos , Masculino , Cambios Post Mortem , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/metabolismo , Corteza Prefrontal/fisiopatología , Ratas , Ratas Sprague-Dawley , Esquizofrenia/fisiopatología , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiologíaRESUMEN
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. RESULTS: Currently, 80% of postmortem BPD studies were derived from just two brain repositories worldwide: the Stanley Brain Collection (69%) and Harvard Brain Tissue Resource Center (HBTRC) (11%) (combined subjects n = 72). The NIMH Brain Collection collected BPD cases four times less frequently than cases with schizophrenia, despite similar prevalence rates for these disorders. Only 53% of cases referred to the NIMH collection as BPD met DSM-IV criteria, with inadequate documentation and comorbid substance abuse as primary confounds for diagnosis in the remaining 47% of cases. CONCLUSIONS: Accurate identification and diagnosis of BPD is a central obstacle to BPD brain collection. Comorbid substance abuse and manner of death are two of many critical factors to consider in BPD postmortem studies. Difficulties in BPD brain collection, coupled with the cessation of brain collection by the Stanley Brain Collection, make the need for alternative BPD brain sources imperative. Recommendations for future BPD tissue collection are offered.
Asunto(s)
Autopsia/métodos , Trastorno Bipolar/patología , Cambios Post Mortem , Adulto , Encéfalo/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Bancos de Tejidos , Adulto JovenRESUMEN
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. Next-of-kin interviews identified almost twice as many cocaine and cannabis cases as Medical Examiner (ME) case histories, and were crucial in establishing a detailed lifetime substance use history. Toxicology identified 91% cocaine, 68% cannabis, 80% phencyclidine and 100% opioid cases, with hair testing increasing detection for all drug classes. A cocaine or cannabis use history was corroborated by general toxicology with 50% and 32% sensitivity, respectively, and with 82% and 64% sensitivity by hair testing. Hair testing corroborated a positive general toxicology for cocaine and cannabis with 91% and 100% sensitivity, respectively. Case history corroborated hair toxicology with 38% sensitivity for cocaine and 79% sensitivity for cannabis, suggesting that both case history and general toxicology underestimated cocaine use. Identifying ante-mortem substance use in human postmortem cases are key considerations in case diagnosis and for characterization of disorder-specific changes in neurobiology. The sensitivity and specificity of substance use assessments increased when ME case history was supplemented with structured next-of-kin interviews to establish a detailed lifetime substance use history, while comprehensive toxicology, and hair testing in particular, increased detection of recent illicit substance use.
Asunto(s)
Autopsia , Médicos Forenses , Drogas Ilícitas/análisis , Trastornos Relacionados con Sustancias/patología , Líquidos Corporales/química , Cerebelo/química , Cerebelo/patología , Trastornos Relacionados con Cocaína/diagnóstico , Trastornos Relacionados con Cocaína/patología , Cabello/química , Humanos , Abuso de Marihuana/diagnóstico , Abuso de Marihuana/patología , Anamnesis , Análisis de Secuencia por Matrices de Oligonucleótidos , Trastornos Relacionados con Opioides/diagnóstico , Trastornos Relacionados con Opioides/patología , Abuso de Fenciclidina/diagnóstico , Abuso de Fenciclidina/patología , Sensibilidad y Especificidad , Trastornos Relacionados con Sustancias/diagnósticoRESUMEN
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. In schizophrenia, we found significantly higher levels of mGluR2 mRNA in the PFC white matter. The expression of mGluR2, 3 in DA cells provide a mechanism for glutamate to modulate dopamine release in the human brain and this species-specific difference may be critical to understanding rodent models in schizophrenia.
Asunto(s)
Dopamina/metabolismo , Ácido Glutámico/metabolismo , Mesencéfalo/metabolismo , Corteza Prefrontal/metabolismo , Receptores de Glutamato Metabotrópico/genética , Esquizofrenia/genética , Esquizofrenia/metabolismo , Adolescente , Adulto , Anciano , Cuerpo Estriado/metabolismo , Cuerpo Estriado/fisiopatología , Femenino , Regulación de la Expresión Génica/genética , Humanos , Masculino , Mesencéfalo/fisiopatología , Persona de Mediana Edad , Vías Nerviosas/metabolismo , Vías Nerviosas/fisiopatología , Corteza Prefrontal/fisiopatología , ARN Mensajero/metabolismo , Esquizofrenia/fisiopatología , Sustancia Negra/metabolismo , Sustancia Negra/fisiopatología , Área Tegmental Ventral/metabolismo , Área Tegmental Ventral/fisiopatología , Adulto JovenRESUMEN
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. In secondary N-methyl analogues, a bromo substituent in the adjacent ring position (14a) imparted high affinity (KI = 7.4 nM) whereas a methyl substituent did not (14c). The tolerance for nonhydrophilic thioether substituents in the 6-position opens up the possibility of developing new sensitive positron emission tomography radioligands for imaging human Abeta plaques in Alzheimer's disease, especially in view of the amenability of thioethers to be labeled with carbon-11 or fluorine-18 through S-alkylation reactions. The structure-activity relationships revealed in this study extends insight into the topography of the binding site for IMPY-like ligands in human Abeta plaques.
Asunto(s)
Péptidos beta-Amiloides/metabolismo , Compuestos de Anilina/síntesis química , Imidazoles/síntesis química , Yodo , Piridinas/síntesis química , Anciano de 80 o más Años , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/química , Compuestos de Anilina/química , Compuestos de Anilina/farmacología , Encéfalo/metabolismo , Femenino , Humanos , Imidazoles/química , Imidazoles/farmacología , Ligandos , Fragmentos de Péptidos/química , Unión Proteica , Piridinas/química , Piridinas/farmacología , Ensayo de Unión Radioligante , Relación Estructura-ActividadRESUMEN
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. METHODS: We assessed the contribution of multiple variables to messenger RNA (mRNA) expression of reference (housekeeping) genes measured by reverse transcriptase-polymerase chain reaction (RT-PCR) by multiple regression analysis in a large number (N = 143) of autopsy samples from the hippocampus and white and grey matter of the dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia and normal control subjects. RESULTS: The strongest predictor of gene expression was total RNA quality. Other significant factors included pH, postmortem interval, age and the duration of the agonal state, but the importance of these factors depended on transcript measured, brain region analyzed, and diagnosis. The quality of RNA obtained from the DLPFC white matter was also adversely affected by smoking. CONCLUSIONS: Our results show that normalization of expression data of target genes with a geometric mean of multiple housekeeping genes should be used to control for differences in RNA quality between samples. The results also suggest that accurate assessment of other confounding factors and their inclusion as regressors in the analysis is critical for obtaining reliable and accurate quantification of mRNA expression.
Asunto(s)
Encéfalo/fisiopatología , Regulación de la Expresión Génica/fisiología , Expresión Génica/fisiología , Esquizofrenia/genética , Esquizofrenia/patología , Adulto , Factores de Edad , Anciano , Encéfalo/metabolismo , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cambios Post Mortem , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Factores de TiempoRESUMEN
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. The most prominent feature induced by aluminum in rabbit brain is a neurofibrillary degeneration that shares some similarity with the neurofibrillary tangles found in Alzheimer's disease patients. In the present review we discuss data from our laboratory and others, on the effects of aluminum on behaviour, neurologic function and morphology, using aluminum administered to rabbits via different routes. Finally, we will examine data on the possible cellular mechanisms underlying aluminum neurotoxicity, and potential neuroprotective strategies against aluminum toxicity.
Asunto(s)
Enfermedad de Alzheimer/inducido químicamente , Enfermedad de Alzheimer/patología , Encéfalo/efectos de los fármacos , Encéfalo/patología , Modelos Animales de Enfermedad , Degeneración Nerviosa/inducido químicamente , Degeneración Nerviosa/patología , Compuestos Organometálicos/toxicidad , Pironas/toxicidad , Enfermedad de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/efectos de los fármacos , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Apoptosis/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/antagonistas & inhibidores , Proteína 11 Similar a Bcl2 , Encéfalo/metabolismo , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de Transporte de Membrana Mitocondrial/efectos de los fármacos , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Poro de Transición de la Permeabilidad Mitocondrial , Degeneración Nerviosa/metabolismo , Ovillos Neurofibrilares/efectos de los fármacos , Ovillos Neurofibrilares/metabolismo , Ovillos Neurofibrilares/patología , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Conejos , Proteína X Asociada a bcl-2/efectos de los fármacosRESUMEN
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 4.0 sodium acetate buffer and solid phase extraction. Extracts were derivatized with N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide and N,O-bis(trimethylsilyl) trifluoroacetamide. Separation and quantification were accomplished on a bench-top positive chemical ionization capillary gas chromatograph/mass spectrometer with selected ion monitoring. Eight deuterated analogs were used as internal standards. Limits of quantification were 50 ng/g of brain. Calibration curves were linear to 1000 ng/g for anhydroecgonine methyl ester and 6-acetylmorphine, and to 2000 ng/g for all other analytes. Accuracy across the linear range of the assay ranged from 90.2 to 112.2%, and precision, as percent relative standard deviation, was less than 16.6%. Quantification of drug concentrations in brain is a useful research tool in neurobiology and in forensic and postmortem toxicology, identifying the type, relative magnitude, and recency of abused drug exposure. This method will be employed to quantify drug concentrations in human postmortem brain in support of basic and clinical research on the physiologic, biochemical, and behavioral effects of drugs in humans.
Asunto(s)
Anfetamina/análisis , Química Encefálica , Encéfalo/metabolismo , Cocaína/análisis , Cromatografía de Gases y Espectrometría de Masas/métodos , Narcóticos/análisis , Anfetamina/química , Calibración , Cocaína/química , Humanos , Narcóticos/química , Sensibilidad y EspecificidadRESUMEN
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. Densities of ChAT mRNA-positive neurons, ChAT mRNA expression per neuron, PPS mRNA-positive neurons, and beta-actin mRNA expression levels were measured. RESULTS: There were no significant differences between the two groups in densities of PPS mRNA-positive neurons and levels of beta-actin mRNA expression throughout the striatum, or in densities of ChAT mRNA-positive neurons in the caudate nucleus or putamen. However, in the ventral striatum, the mean density of ChAT mRNA-positive neurons was reduced to 26% of control levels in the schizophrenic group. CONCLUSIONS: There is a reduction in number or function of the cholinergic interneurons of the ventral striatum in schizophrenia.
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Ganglios Basales/citología , Colina O-Acetiltransferasa/metabolismo , Interneuronas/metabolismo , Esquizofrenia/genética , Esquizofrenia/metabolismo , Adulto , Anciano , Ganglios Basales/metabolismo , Recuento de Células/métodos , Colina O-Acetiltransferasa/genética , Femenino , Humanos , Hibridación in Situ/métodos , Masculino , Persona de Mediana Edad , Cambios Post MortemRESUMEN
BACKGROUND: Postmortem human brain research is an important approach for identifying the cellular, molecular, and genetic pathways involved in the pathophysiology of psychiatric disorders. One critical component in postmortem research is the reliability of psychiatric diagnoses used to define study cohorts. Finding reliable methods for assessing lifetime psychiatric diagnoses in subjects after death is extremely challenging. METHODS: Two commonly used approaches were compared: psychiatric record reviews and postmortem family interviews. We hypothesized that these two methods would lead to more diagnostic agreement for subjects with schizophrenia than those with mood disorders. For 37 cases, psychiatric records were reviewed retrospectively using the Diagnostic Evaluation After Death, and family members were interviewed using the Structured Clinical Interview for DSM-IV. RESULTS: Comparison of diagnoses derived from these two approaches generated an overall kappa coefficient of .67. Kappa coefficients for the schizophrenia cohort were .94, .68 for the major depressive disorder cohort, and .58 for the bipolar disorder cohort. CONCLUSIONS: Thus, although it may be sufficient to establish the postmortem diagnosis of schizophrenia using one of the two methods, the best method for reaching an accurate postmortem diagnosis for mood disorders is more difficult to determine and requires further study.
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Trastornos Mentales/diagnóstico , Cambios Post Mortem , Escalas de Valoración Psiquiátrica , Reproducibilidad de los Resultados , Adulto , Autopsia/métodos , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Humanos , Masculino , Trastornos Mentales/clasificación , Persona de Mediana EdadRESUMEN
SREB is a subfamily of G-protein-coupled receptors, which consists of SREB1 (GPR27), SREB2 (GPR85), and SREB3 (GPR173). Its high evolutionary conservation and predominant expression in the CNS suggest that SREB family members and their undiscovered ligand(s) may have significant functions in the nervous system. SREB2 is the most conserved receptor throughout vertebrate evolution. As a first step in understanding the function of the SREB family, we have determined the anatomical gene expression profile of SREB2 in adult human, monkey, and rat forebrain using in situ hybridization histochemistry. The expression pattern of SREB2 mRNA was well conserved across three mammalian species. SREB2 mRNA was expressed in neurons throughout the brain and the most abundant expression was detected in the hippocampal dentate gyrus in all species examined. The areas expressing high levels of SREB2 mRNA overlap with brain structures known to possess high levels of plasticity, namely, the hippocampal formation, olfactory system, and supraoptic and paraventricular nuclei. Further, the anatomical expression of SREB1 and SREB3 overlapped with that of SREB2 in the adult monkey brain. Together, these data suggest a possible link between SREB family and neural plasticity, which may explain its extremely high conservation throughout vertebrate evolution.
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Expresión Génica/fisiología , Proteínas del Tejido Nervioso/metabolismo , Prosencéfalo/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animales , Autorradiografía/métodos , Haplorrinos , Humanos , Hibridación in Situ/métodos , Proteínas del Tejido Nervioso/genética , Neuronas/metabolismo , Cambios Post Mortem , Prosencéfalo/citología , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Receptores Acoplados a Proteínas G/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodosRESUMEN
BACKGROUND: Numerous recent studies of postmortem schizophrenic brains have reported the presence of structural abnormalities in the dorsolateral prefrontal cortex (dlPFC) that are consistent with a reduction of neuropil. Ventrolateral prefrontal areas have been studied less extensively, and therefore it is not clear whether these cortices exhibit pathologic abnormalities of the same type and magnitude. Because thought disturbances in schizophrenic patients involve language processing, we have performed a morphometric analysis of Broca's area in the ventral frontal lobe. METHODS: Neuronal and glial density and somal size were assessed via stereologic cell counting in postmortem samples of Broca's area 44 in 9 schizophrenic patients and 14 normal controls. Cell density was reexamined in dorsolateral prefrontal area 9 as an internal control. RESULTS: We did not detect abnormalities in overall or laminar neuronal density, glial density, cortical thickness, or somal size in area 44 of schizophrenic patients. In contrast, neuronal density in area 9 exhibited a 12% increase in the schizophrenic cohort, replicating previous findings. In addition, there was a significant effect of disease on laminar neuronal density in area 9, with neuronal density tending to be higher (7%-29%) in all layers. CONCLUSIONS: The absence of significant cytoarchitectonic abnormalities in Broca's area in the same brains in which the dlPFC exhibited an increase in neuronal density suggests that the neuropil deficit is a regionally specific pathologic finding in schizophrenia and indicates that the dlPFC is a particularly vulnerable target of the disease process.
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Lóbulo Frontal/citología , Corteza Prefrontal/patología , Esquizofrenia/patología , Adulto , Anciano , Análisis de Varianza , Recuento de Células , Femenino , Lóbulo Frontal/patología , Humanos , Masculino , Persona de Mediana Edad , Neuroglía/citología , Neuroglía/patología , Neuronas/citología , Neuronas/patología , Corteza Prefrontal/citología , Esquizofrenia/diagnóstico , Lenguaje del EsquizofrénicoRESUMEN
CONTEXT: The schizophrenia-susceptibility gene dysbindin (DTNBP1 on 6p22.3) encodes a neuronal protein that binds to beta-dystrobrevin and may be part of the dystrophin protein complex. Little is known about dysbindin expression in normal or schizophrenic brain. OBJECTIVES: To determine whether brain regions implicated in schizophrenia express dysbindin and whether abnormal levels of dysbindin messenger RNA (mRNA) may be found in this disorder and to test whether sequence variations in the dysbindin gene in the promoter region, 5' and 3' untranslated regions, or introns would affect dysbindin mRNA levels. METHODS: In patients with schizophrenia and controls, we compared dysbindin, synaptophysin, spinophilin, and cyclophilin mRNA levels in the dorsolateral prefrontal cortex and dysbindin mRNA levels in the midbrain by in situ hybridization. We genotyped brain DNA at 11 single nucleotide polymorphisms to determine whether genetic variation in the dysbindin gene affects cortical dysbindin mRNA levels. MAIN OUTCOME MEASURES: Quantitative assessment of dysbindin mRNA levels across various brain regions and comparative studies of dysbindin mRNA levels in brains of patients with schizophrenia compared with normal controls. RESULTS: Dysbindin mRNA was detected in the frontal cortex, temporal cortex, hippocampus, caudate, putamen, nucleus accumbens, amygdala, thalamus, and midbrain of the adult brain. Patients with schizophrenia had statistically significantly reduced dysbindin mRNA levels in multiple layers of the dorsolateral prefrontal cortex, whereas synaptophysin, spinophilin, and cyclophilin mRNA levels were unchanged. Dysbindin mRNA levels were quantitatively reduced in the midbrain of patients with schizophrenia, but not statistically significantly. Cortical dysbindin mRNA levels varied statistically significantly according to dysbindin genotype. CONCLUSIONS: Dysbindin mRNA is expressed widely in the brain, and its expression is reduced in schizophrenia. Variation in dysbindin mRNA levels may be determined in part by variation in the promoter and the 5' and 3' untranslated regions. These data add to the evidence that dysbindin is an etiologic factor in schizophrenia risk.