Gene expression profiling in genetic animal models of provide elements to unveil the molecular mechanisms underlying epileptogenesis in rodents

OBJECTIVE: The objective of this study was to characterize and compare the genetic profile of two rodent models of epilepsy (Wistar Audiogenic Rat - WAR and rats with generalized epilepsy with absence seizures-GEAS) using gene expression analysis METHODS: We used microarray technology for gene expression analysis. RESULTS: The analysis of gene expression profiles in WAR showed among genes up-regulated Neurod1, involved in the development of the cochlear duct. In addition, we found significant differences in gene expression of Apbb1, Foxg1 and Scn1A. GEAS rats had differentially expressed genes related to the development of central nervous system, as well as genes involved in the MAPK pathway, transcription factors, neuronal migration and apoptosis. CONCLUSION: This study may help to clarify the underlying molecular mechanism that leads to the predisposition to seizures in these animals. Our results indicate the activation of distinct molecular pathways in both models.OBJETIVO: O objetivo desse trabalho foi caracterizar e comparar o perfil genético de dois modelos de epilepsia em roedores (Wistar Audiogenic Rat - WAR e generalized epilepsy with absence seizures - GEAS) através da análise da expressão gênica em larga escala. MÉTODOS: Para a análise do perfil de expressão gênica foi utilizada a técnica de microarranjos de DNA (microarray). RESULTADOS: Na linhagem WAR a análise do perfil de expressão mostrou que dentro os genes mais hiperexpressos está o Neurod1, envolvido com o desenvolvimento do ducto coclear. Além desse encontramos também diferenças significativas na expressão dos genes Apbb1, Foxg1 e Scn1A. Já nos animais GEAS os genes com maior expressão diferencial foram àqueles relacionados com o desenvolvimento do sistema nervoso central, além de genes envolvidos com a via da MAPK, fatores de transcrição, migração neuronal e apoptose. CONCLUSÃO: Esta análise pode ajudar a esclarecer o mecanismo molecular subjacente que leva a predisposição a crises nesses animais. Até o momento, nossos resultados apontam para a ativação de vias moleculares distintas em ambos os modelos.505

Fluoro-Jade, but not Fluoro-Jade B, stains non-degenerating cells in brain and retina of embryonic and neonatal rats

Fluoro-Jade (FJ) and Fluoro-Jade B (FJB) are fluorescein derivatives currently used to stain brain cells under degeneration. In this study, we investigated the FJ staining of nondegenerating cells in embryonic and neonatal rat brain and retina. In embryonic rat brain (embryonic day 15; E15), very intense staining of cells was observed. The number of FJ-stained cells and the intensity of staining decreased with increasing in animal age, being almost absent by postnatal day 16 (P16). Only a few cells in neonatal rat brain were in the process of cell death, as verified by the TUNEL technique. The H-stained cells in neonatal brain were positive for the neuronal marker neuronal nuclei antigen (NeuN). In retina, FJ stained mainly cells from the ganglion cell layer at P2 and the neuroblastic layer at P2 and P6. In contrast to FJ, FJB did not stain nondegenerating cells in embryonic and neonatal rats. These results show that in addition to staining degenerating brain cells, FJ also stains nondegenerating central nervous system cells in embryonic and neonatal stages. (C) 2004 Elsevier B.V. All rights reserved.10291243

LINKGEN: A new algorithm to process data in genetic linkage studies

Genetic linkage studies using whole genome scans are useful approaches for identifying genes related to human diseases. In general, these studies require genotyping of a large number of markers, which are used in statistical analysis. Recent technology has allowed easy genotyping of a large number of markers in less time; therefore, interface programs are required for manipulation of these large data sets. We present a new algorithm, which processes input data in LINK-AGE format from data analyzed by automated genotyping systems. The algorithm was implemented in PERL script and R environment. Validation was performed with genotyped data from 127 individuals and 720 microsatellite markers of two whole genome scans. Our results showed a significant decrease in data processing time. In addition, this algorithm provides unbiased allele frequency estimation used for linkage analysis. LINKGEN is a freely available online tool and allows easier, faster, and reliable manipulation of large genotyping data sets. (C) 2008 Elsevier Inc. All rights reserved.91654454

THE SCN2A gene is not a likely candidate for familial mesial temporal lobe epilepsy

A transgenic mouse model carrying a mutation in the Scn2a gene showed chronic focal seizures associated with extensive cell loss and gliosis in the hippocampus, a similar phenotype found in familial mesial temporal lobe epilepsy (FMTLE). Our objective was to test whether the human homolog of the Scn2a gene is responsible for hippocampal abnormalities in FMTLE by linkage analysis. We conclusively ruled out the SCN2A gene as candidate in FMTLE. (c) 2006 Elsevier B.V. All rights reserved.714170023323

Prospective neuroimaging study in hereditary spastic paraplegia with thin corpus callosum

Our objective was to estimate the frequency as well as to establish the clinical and neuroimaging profile of hereditary spastic paraplegia with thin corpus callosum (HSP-TCC). HSP-TCC was recognized as a specific clinical subtype of HSP and mapped to chromosome (ch) 15q13-15 in Japanese families. It has been considered rare in western countries. We assessed 45 patients with autosomal recessive HSP from 20 different families in search of clinical and imaging criteria or the diagnosis of HSP-TCC. In addition, HSP-TCC patients underwent further neurological, imaging and genetic evaluation. MRI scans were performed in a 2T scanner and sagittal T1 weighted images used for semiautomated volumetric measurements of corpus callosum, cerebellum, and brain. In seven patients, a 2-year follow-up MRI scan was performed. We genotyped seven microsatellite markers flanking the 15q13-15 candidate region and calculated two-point and multipoint LOD scores (Z). We identified 13 patients from seven unrelated families with HSP-TCC. MRI showed significant corpus callosum, cerebral and cerebellar volumetric reductions (P < 0.001, P = 0.03, and P = 0.01, respectively). In the prospective analysis, we found progressive corpus callosum atrophy (P = 0.04). Two-point and multipoint LOD scores were significantly negative for markers genotyped on ch 15q. However, independent pedigree analysis did not yield significant results. HSP-TCC was found in 35% of families with autosomal recessive HSP. MRI volumetry showed cerebral and cerebellar atrophy in association with progressive corpus callosum thinning. Genetic studies did not show evidence for linkage to ch 15q. (c) 2007 Movement Disorder Society.22111556156

MRI and EEG as long-term seizure outcome predictors in familial mesial temporal lobe epilepsy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objective: To evaluate the natural history and outcome predictors in familial mesial temporal lobe epilepsy (FMTLE). Methods: We conducted a longitudinal study of 103 individuals from 17 FMTLE families (mean follow-up: 7.6 years). We divided subjects into 3 groups: FMTLE (n = 53), unclassified seizure (n = 18), and asymptomatics (n 5 32). We divided FMTLE patients into 3 subgroups: seizure-free (n = 19), infrequent (n = 17) seizures, and frequent (n = 17) seizures and further reclassified them into favorable and poor outcome. We defined hippocampal atrophy (HA) by visual MRI analysis and performed volumetry in those who had 2 MRIs. Results: FMTLE patients with infrequent seizures evolved to either frequent seizures (17.6%) or seizure freedom (23.5%). In the seizure-free group, most remained seizure-free and 21% developed infrequent seizures. All patients with frequent seizures remained in the same status or underwent surgery. Twelve percent of the asymptomatics and 22% of the unclassified-seizure group evolved to FMTLE with infrequent seizures. Predictive factors of poor outcome were presence of HA (p = 0.0192) and interictal epileptiform discharges (p = 0.0174). The relationship between initial precipitating incidents and clinical outcome was not significant although a tendency was observed (p = 0.055). Use of antiepileptic drugs and secondary generalized seizures during the patient's lifetime did not predict poor outcome. We observed progression of HA only in the group with frequent seizures. Conclusion: Most patients with FMTLE continued in the same clinical status. However, patients with frequent seizures had progression of HA and none improved except those who underwent surgery. Interictal epileptiform discharges and HA predicted poorer outcome in FMTLE, and there was a tendency in favor of initial precipitating incidents as outcome predictors. Neurology (R) 2012;79:2349-2354o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.792423492354CInAPCe (Cooperacao Interinstitucional de Apoio a Pesquisa sobre o Cerebro)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)UCBCIHR [MOP-93614]Fonds de la recherche en sante du QuebecCECRAmerican Epilepsy Society Early Career Physician-Scientist AwardQuebec Bio-Imaging NetworkConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [05/56578-4, 06/59101-7]CIHR [MOP-93614

A comparison between different reference genes for expression studies in human hippocampal tissue

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The reliability of gene expression studies by mRNA quantification is highly dependent upon several experimental procedures, including the choice of reference genes used for data normalization. In order to contribute to gene expression studies in mesial temporal lobe epilepsy (MTLE) we used microarray data, followed by real time quantitative PCR validation of selected housekeeping genes, to determine the most appropriate reference genes to be used in human hippocampal tissue gene expression studies. Our results unequivocally showed a significant impact of the reference gene chosen for normalization on the overall results of expression studies, clearly demonstrating the importance of adequate validation using stable reference genes. In addition, we found that HPRT, NSE, SDHA and SYP are suitable genes to be used as reference for normalization in expression studies of hippocampal tissue obtained from patients with MTLE. (C) 2012 Published by Elsevier B.V20814447Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2005/56578-4, 2008/54789-6, 2010/17440-5