CDK5 and MAPT Gene Expression in Alzheimer's Disease Brain Samples.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by extracellular amyloid plaque and neurofibrillary tangles in the brain. Studies have shown that neurons are able to re-enter the cell cycle, but not enough to enable full replication. This leads to cell death and consequent neurodegeneration. OBJECTIVE: This study aimed to characterize the expression of the MAPT gene and CDK5 (the gene involved in cell cycle regulation) in brain samples from patients with AD and controls. METHOD: The real-time-PCR technique was used to characterize 150 samples from three areas of the brain (entorhinal cortex, auditory cortex, and hippocampus) of 26 AD patients and 24 healthy elderly subjects. RESULTS: When the brain samples were analyzed collectively, a decrease in CDK5 and MAPT gene expression was found in AD patients. When each groups' samples were separated by area of the brain and compared, significant differences were found in CDK5 expression in the hippocampus and the entorhinal cortex. In both cases, mRNA was lower in the AD group (p=0.0001); however, the same analysis using the MAPT gene revealed no significant statistical differences. No statistical differences were found when gene expression was compared between the different regions of the brain within each group. CONCLUSION: These results may contribute to a better understanding of the involvement of CDK5 and MAPT genes in AD in that they consider different areas of the brain that are affected differently based on disease progression. The main challenge is to establish an effective therapy for this debilitating disease in the future.

Change in INSR, APBA2 and IDE Gene Expressions in Brains of Alzheimer's Disease Patients.

BACKGROUND: Alzheimer's disease (AD) is defined as a progressive and irreversible neurodegenerative disorder, the onset of which is mainly characterized by decreased cognition, memory loss, and mental confusion. OBJECTIVE: This study sought to quantify mRNA expression of the APBA2, INSR and IDE genes in brain samples from patients with AD and controls. METHODS: We investigated the mRNA expression of the APBA2, INSR and IDE genes in 150 RNA samples from entorhinal cortex, auditory cortex, and the hippocampus of individuals with AD and elderly controls using real time PCR. APOE genotypes were determined by PCR-RFLP. RESULTS: When the total brain samples were analyzed collectively, a decrease in IDE gene expression was found in AD patients relative to healthy elderly controls. However, when the samples were analyzed separately according to the region of the brain, there was a significant upregulation of INSR expression in the hippocampus and the entorhinal cortex in the AD patient group. We did not observe any statistical differences when gene expression was compared in the different regions of the brain of AD patients. When the E4 allele of apolipoprotein-E was considered in AD patients, the presence of this allele was found to be associated with decreased APBA2 gene expression. The same analysis using the INSR and IDE genes showed no significant statistical differences. CONCLUSION: These results support the hypothesis that APBA2, IDE, and particularly INSR gene expression in different areas of Alzheimer's patient's brains could represent new markers for use in clinical diagnoses in the near future.

Differential Expression of Ribosomal Genes in Brain and Blood of Alzheimer's Disease Patients.

Changes in rRNA and rDNA expression have been associated with cellular and organism aging and have been linked to Alzheimer's disease (AD) pathogenesis. In this study, we investigated the mRNA expression of ribosomal genes (28S/18S) and ß-amyloid precursor protein (APP) in different post mortem brain tissue regions (the entorhinal and auditory cortices and the hippocampus) of AD patients and elderly control subjects and also evaluated the extent of expression in peripheral blood from young, healthy, elderly, and Alzheimer's disease patients in order to investigate whether these individuals experienced the effects of aging. The comparative threshold cycle (CT) method via Real Time Polymerase Chain Reaction and the Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) were used to analyze gene expression and the Apolipoprotein E (APOE) genotype, respectively. When the brain areas were analyzed collectively, we observed a significant decrease in APP expression and a significant increase in levels of mRNA of 18S and 28S in Alzheimer's disease patients compared to healthy elderly individuals. Furthermore, there was a significant upregulation of 28SrRNA in the entorhinal cortex and hippocampus, but not in the auditory cortex of patients with AD. On the other hand, tests of blood samples verified a decreased expression of 28S rRNA in patients with AD. These results support the hypothesis that changes in rRNA are present in AD patients, are tissue-specific, and seem to occur independently and differently in each tissue. However, the next challenge is to discover the mechanisms responsible for the differences in expression observed in the blood and the brain in both healthy elderly individuals and Alzheimer's disease patients, as well as the impact of these genes on AD pathogenesis.

HS3ST2 expression is critical for the abnormal phosphorylation of tau in Alzheimer's disease-related tau pathology.

Heparan sulphate (glucosamine) 3-O-sulphotransferase 2 (HS3ST2, also known as 3OST2) is an enzyme predominantly expressed in neurons wherein it generates rare 3-O-sulphated domains of unknown functions in heparan sulphates. In Alzheimer's disease, heparan sulphates accumulate at the intracellular level in disease neurons where they co-localize with the neurofibrillary pathology, while they persist at the neuronal cell membrane in normal brain. However, it is unknown whether HS3ST2 and its 3-O-sulphated heparan sulphate products are involved in the mechanisms leading to the abnormal phosphorylation of tau in Alzheimer's disease and related tauopathies. Here, we first measured the transcript levels of all human heparan sulphate sulphotransferases in hippocampus of Alzheimer's disease (n = 8; 76.8 ± 3.5 years old) and found increased expression of HS3ST2 (P < 0.001) compared with control brain (n = 8; 67.8 ± 2.9 years old). Then, to investigate whether the membrane-associated 3-O-sulphated heparan sulphates translocate to the intracellular level under pathological conditions, we used two cell models of tauopathy in neuro-differentiated SH-SY5Y cells: a tau mutation-dependent model in cells expressing human tau carrying the P301L mutation hTau(P301L), and a tau mutation-independent model in where tau hyperphosphorylation is induced by oxidative stress. Confocal microscopy, fluorescence resonance energy transfer, and western blot analyses showed that 3-O-sulphated heparan sulphates can be internalized into cells where they interact with tau, promoting its abnormal phosphorylation, but not that of p38 or NF-κB p65. We showed, in vitro, that the 3-O-sulphated heparan sulphates bind to tau, but not to GSK3B, protein kinase A or protein phosphatase 2, inducing its abnormal phosphorylation. Finally, we demonstrated in a zebrafish model of tauopathy expressing the hTau(P301L), that inhibiting hs3st2 (also known as 3ost2) expression results in a strong inhibition of the abnormally phosphorylated tau epitopes in brain and in spinal cord, leading to a complete recovery of motor neuronal axons length (n = 25; P < 0.005) and of the animal motor response to touching stimuli (n = 150; P < 0.005). Our findings indicate that HS3ST2 centrally participates to the molecular mechanisms leading the abnormal phosphorylation of tau. By interacting with tau at the intracellular level, the 3-O-sulphated heparan sulphates produced by HS3ST2 might act as molecular chaperones allowing the abnormal phosphorylation of tau. We propose HS3ST2 as a novel therapeutic target for Alzheimer's disease.

PSEN1 and PSEN2 gene expression in Alzheimer's disease brain: a new approach.

Presenilin 1 (PSEN1) and presenilin 2 (PSEN2) genes encode the major component of y-secretase, which is responsible for sequential proteolytic cleavages of amyloid precursor proteins and the subsequent formation of amyloid-ß peptides. 150 RNA samples from the entorhinal cortex, auditory cortex and hippocampal regions of individuals with Alzheimer's disease (AD) and controls elderly subjects were analyzed with using real-time rtPCR. There were no differences between groups for PSEN1 expression. PSEN2 was significantly downregulated in the auditory cortex of AD patients when compared to controls and when compared to other brain regions of the patients. Alteration in PSEN2 expression may be a risk factor for AD.

Glycosaminoglycans from aged human hippocampus have altered capacities to regulate trophic factors activities but not Aß42 peptide toxicity.

Glycosaminoglycans (GAGs) are major extracellular matrix components known to tightly regulate cell behavior by interacting with tissue effectors as trophic factors and other heparin binding proteins. Alterations of GAGs structures might thus modify the nature and extent of these interactions and alter tissue integrity. Here, we studied levels and composition of GAGs isolated from adult and aged human hippocampus and investigated if their changes can influence the function of important trophic factors and the Aß42 peptide toxicity. Biochemical analyses showed that heparan sulfates are increased in the aged hippocampus. Moreover, GAGs from aged hippocampus showed altered capacities to regulate trophic factor activities without changing their capacities to protect cells from Aß42 toxicity, compared to adult hippocampus GAGs. Structural alterations in GAGs from elderly were suggested by differential transcripts levels of key biosynthetic enzymes. C5-epimerase and 2-OST expressions were decreased while NDST-2 and 3-OST-4 were increased; in contrast, heparanase expression was unchanged. Results suggest that alteration of GAGs in hippocampus of aged subjects could participate to tissue impairment during aging.

Neurobiologia da Cannabis: do sistema endocanabinoide aos transtornos por uso de Cannabis / Neurobiology of Cannabis: from the endocannabinoid system to cannabis-related disorders

OBJETIVOS: Diante das lacunas na efetividade das terapêuticas para transtornos por uso de Cannabis, a droga ilícita mais consumida no mundo, este trabalho propõe-se a rever os conhecimentos sobre o substrato neuroanatômico, biomolecular e celular do sistema endocanabinoide, descrever os mecanismos de neuroplasticidade dependente dos canabinoides e relacioná-los com a neurobiologia dos transtornos por uso de Cannabis (abuso e dependência). MÉTODOS: Recorreu-se às bases de dados Medline, Scopus e ISI Web of Knowledge; as palavras-chave pesquisadas foram "Cannabis", "neurobiology", "endocannabinoid system", "endocannabinoids", "receptors, cannabinoid", "neuronal plasticity", "long-term synaptic depression", "long-term potentiation", "marijuana abuse" e "tetrahydrocannabinol". Foram incluídos 80 trabalhos nesta revisão. DISCUSSÃO: A distribuição neuroanatômica, celular e biomolecular do sistema endocanabinoide adequa-se perfeitamente às suas funções de neuromodulação (via neuroplasticidade e metaplasticidade), nomeadamente em vias relacionadas aos transtornos por uso de substâncias. Os canabinoides exógenos perturbam essas funções. CONCLUSÃO: O sistema endocanabinoide contribui para a definição de setpoints em diversas vias neuronais, incluindo vias cruciais na instalação de transtornos por uso de substâncias; com o uso de Cannabis, esses setpoints tornar-se-ão mais permissivos, facilitando os transtornos por uso de Cannabis. Os avanços no entendimento da neurobiologia da Cannabis abrem uma janela de oportunidades para novas estratégias terapêuticas nos transtornos por uso de Cannabis.

OBJECTIVES: Given the challenges arising from the poor effectiveness of therapies for Cannabis-related disorders, the most commonly used illicit drug in the world, this paper aims to review the present knowledge about the neuroanatomic, biomolecular and cellular substrate of the endocannabinoid system, describing the mechanisms of cannabinoid-dependent neuronal plasticity and relating them with the neurobiology of Cannabis-related disorders (abuse and dependence). METHODS: Medline, Scopus and ISI Web of Knowledge were searched for the keywords "Cannabis", "neurobiology", "endocannabinoid system", "endocannabinoids", "receptors, cannabinoid", "neuronal plasticity", "long-term synaptic depression", "long-term potentiation", "marijuana abuse" and "tetrahydrocannabinol". Eighty studies were included in this review. DISCUSSION: The neuroanatomical, cellular and biomolecular characterization of the endocannabinoid system serves perfectly its neuromodulatory neuroplastic and metaplastic functions, particularly in pathways related to substance-related disorders. Exogenous cannabinoids disrupt these functions. CONCLUSION: The endocannabinoid system contributes to the definition of setpoints in several neuronal pathways, including pathways critical for the development of substance-related disorders; with Cannabis use these setpoints become more permissive, facilitating Cannabis-related disorders. The advances in understanding the neurobiology of Cannabis open a window of opportunities for new therapeutic strategies in Cannabis-related disorders.

Avaliaçäo do teste "Mini-Mental State" em voluntários e pacientes brasileiros / Evaluation of the \"Mini Mental State\" test in Brazilian volunteers and patients

Neste estudo, a escala "Mini-Mental State" (MMS) foi traduzida e adaptada para o português. Aplicou-se o MMS a 20 voluntários sadios com pouca ou nenhuma instruçäo, a 20 voluntários com instruçäo superior e a 33 pacientes psiquiátricos hospitalizados. A reprodutibilidade (inter-rater reliability) entre as duas aplicaçöes obteve um grau de concordância de 85 por cento. Observou-se pontuaçäo abaixo de valor mínimo normal para a populaçäo com menos escolaridade, o que pode levar a resultados falso-positivos para demência. Nos pacientes psiquiátricos internados, o MMS revelou-se um instrumento capaz de quantificar adequadamente o déficit cognitivo de pacientes demenciados pelos critérios estabelecidos pelo DSM-III R

L-dopa, biperideno e excreçäo sebácea na doença de Parkinson

A excreçäo sebácea frontal de 47 parkinsonianos "de novo" antes e após tratamento com anticolinérgico (biperideno), levodopa + IDAA e bromocriptina foi avaliada pelo método do ácido ósmico. Outros 100 parkinsonianos sob terapêutica crônica com biperideno, levodopa + IDAA ou associaçäo de ambos foram avaliados. Parkinsonianos "de novo" do sexo masculino apresentam valores de excreçäo sebácea significativamente mais elevados em relaçäo `as mulheres. Verificou-se que biperideno näo foi eficaz em reduzir o grau de excreçäo sebácea. Já, em relaçäo a L-dopa + IDAA constatou-se que a droga foi efetiva em reduzir o grau de excreçäo sebácea (NC e TRE) tanto no sexo masculino quanto no feminino. Em relaçäo `a bromocriptina (10mg/dia) também constatou-se que houve reduçäo da excreçäo sebácea no sexo masculino. Correlaçäo significante positiva foi verificada entre o NC, tremor, bradieinesia, hipertonia, alteraçöes da marcha e postura e incapacidade funcional, entre parkinsonianos do sexo masculino e faixa etária 50-59 anos, no período pré-tratamento. Após o período de tratamento näo mais havia correlaçäo entre excreçäo sebácea e as manifestaçöes neurológicas da doença de Parkinson. Entre parkinsonianos sob terapêutica crônica verificou-se correlaç-äo positiva e significante entre excreçäo sebácea e bradicinesia. O grau de excreçäo sebácea de parkinsonianos "de novo" sem tratamento näo difere do grau daqueles sob tratamento crônico, exceçäo feita a parkinsonianos com idade >= 60 anos, em que verificou-se maior ggrau de exreçäo sebácea (NC e TRE) em relaçäo ao mesmo sexo e faixa etária, sem tratamento. L-dopa + IDAA foi eficiente em reduzir o grau de excreçäo sebácea de parkinsonianos "de novo", tornando-a...

Tratamento da doença de Parkinson: complicaçöes tardias da levodopaterapia / Treatment of Parkinson's disease: long-term problems of levodopaterapia

Säo revistas as principais complicaçöes encontradas no uso prolongado da levodopa para o tratamento da doença de Parkinson. Entre estas destacam-se: a perda de eficácia, as flutuaçöes do desempenho motor e as alteraçöes psíquicas decorrentes do uso da droga. Discutem-se os fatores implicados na perda de efeito da medicaçäo. Os diversos tipos de flutuaçäo do desempenho motor säo descritos e os mecanismos fisiopatológicos determinantes, comentados. Analisam-se do ponto de vista clínico e fisiopatológico as alteraçöes psíquicas induzidas pela levodopaterapia. Säo abordados ainda os meios disponíveis para o controle dessas dificuldades