Overexpression of N141I PS2 increases γ-secretase activity through up-regulation of Presenilin and Pen-2 in brain mitochondria of NSE/hPS2m transgenic mice / 한국실험동물학회지

Alzheimer's disease (AD) is known to induce alterations of mitochondrial function such as elevation of oxidative stress and activation of apopotosis. The aim of this study was to investigate the effects of human Presenilin 2 mutant (hPS2m) overexpression on the γ-secretase complex in the mitochondrial fraction. To achieve this, alterations of γ-secretase complex expression and activity were detected in the mitochondrial fraction derived from brains of NSE/hPS2m Tg mice and Non-Tg mice. Herein, the following were observed: i) overexpression of the hPS2m gene significantly up-regulated the deposition of Aβ-42 peptides in the hippocampus and cortex of brain, ii) overexpression of hPS2m protein induced alterations of γ-secretase components such as main component protein and activator protein but not stabilization-related proteins, iii) changes in γ-secretase components induced by overexpression of hPS2m protein up-regulated γ-secretase activity in the mitochondrial fraction, and iv) elevation of γ-secretase activity induced production of Aβ-42 peptides in the mitochondrial fraction. Based on these observations, these results indicate that alteration of γ-secretase activity in cells upon overexpression of hPS2m is tightly linked to mitochondrial dysfunction under the specific physiological and pathological conditions of AD.

Descripción genotípica y fenotípica de la enfermedad de Alzheimer tardía y familiar precoz: revisión / Genotypic and phenotypic description of late-onset Alzheimer's disease and early onset familial Alzheimer's: Review / Descrição genotípica e fenotípica da doença de Alzheimer tardia e familiar precoce: revisão

La demencia es la pérdida de varias áreas del funcionamiento cognitivo respecto al nivel premórbido, con deterioro significativo en la funcionalidad. La más común es ocasionada por la enfermedad de Alzheimer, que se define como un trastorno neurodegenerativo que produce una alteración progresiva de la memoria y de otras habilidades mentales, por una pérdida de volumen en los lóbulos temporales, en especial en las áreas mediales como el hipocampo y la corteza entorrinal. Menos del 5% de los pacientes con esta enfermedad presenta formas hereditarias que pueden tener un inicio precoz (antes de los 65 años) o tardío (después de dicha edad). La EA precoz presenta un patrón de herencia autosómico dominante y puede ser causado por mutaciones en el gen de la proteína precursora de amiloide, en presenilina-1 o presenilina-2. Los casos de EA tardía, están influenciados por una genética compleja, con múltiples factores de susceptibilidad y el alelo ApoE4 es el principal y más reconocido. La EA es una enfermedad heterogénea tanto en su genotipo como en su fenotipo que varían en cuanto a intensidad y tipo de síntomas, edad de inicio y severidad de la demencia, de acuerdo con las mutaciones que el paciente presenta y su interacción con factores ambientales.

Dementia is known as the loss of multiple areas of cognitive function with respect to a premorbid condition, involving a significant deterioration in functionality. The most common subtype is Alzheimer's disease, which is defined as a neurodegenerative disorder that causes a progressive deterioration in memory and other mental capacities due to volume loss in temporal lobes, especially in mesial aspects, such as the hippocampus and the entorhinal cortex. Approximately 5% of patients affected by this disease have a hereditary form, with an early onset (before 65 years) or a late onset (after 65 years). Early onset Alzheimer's disease has a genetic autosomal dominant inheritance pattern, which can be caused by mutations in the gene encoding for the amyloid precursor protein, presenilin-1, or presenilin-2. In the cases of late onset Alzheimer's disease, there is a complex genetic influence, with multiple susceptibility factors, where the ApoE4 allele is the main and most recognized factor. Alzheimer's disease is a heterogeneous dementia, both in genotype and phenotype, varying in intensity and symptoms, age of onset, and severity of the disease, depending on the different mutations that a patient may have and the interactions with environmental factors.

A demência é a perda de várias áreas do funcionamento cognitivo com respeito ao nível pré-mórbido, com deterioro significativo na funcionalidade. A mais comum é ocasionada pela doença de Alzheimer, que se define como um transtorno neurodegenerativo que produz uma alteração progressiva da memória e de outras habilidades mentais, por uma perda de volume nos lóbulos temporais, em especial nas áreas mediais como o hipocampo e o córtex entorrinal. Menos de 5% dos pacientes com esta doença apresenta formas hereditárias que podem ter um início precoce (antes dos 65 anos) ou tardio (depois de dita idade). A D.A. precoce apresenta um padrão de herança autossômico dominante e pode ser causado por mutações no gene da proteína precursora de amiloide, em presenilina-1 ou presenilina-2. Os casos de D.A. tardia, estão influenciados por uma genética complexa, com múltiplos fatores de susceptibilidade e o alelo ApoE4 é o principal e mais reconhecido. A D.A. é uma doença heterogénea tanto em seu genótipo como em seu fenótipo que variam em quanto a intensidade e tipo de sintomas, idade de inicio e severidade da demência, de acordo com as mutações que o paciente apresenta e sua interação com fatores ambientais.

Identification of PSEN1 and APP Gene Mutations in Korean Patients with Early-Onset Alzheimer's Disease

Although mutations in three genes, amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2), have been identified as genetic causes of earlyonset Alzheimer s disease (EOAD), there has been a single report on a PSEN1 mutation in Koreans. In the present study, we performed a genetic analysis of six Korean patients with EOAD. Direct sequencing analysis of the APP, PSEN1 and PSEN2 genes revealed two different mutations of the PSEN1 gene (G206S and M233T) and one mutation of the APP gene (V715M) in three patients with age-atonset of 34, 35, and 42 yr, respectively. In addition, two patients with age-at-onset of 55 and 62 yr, respectively, were homozygous for APOE epsilon 4 allele. One woman had no genetic alterations. These findings suggest that PSEN1 and APP gene mutations may not be uncommon in Korean patients with EOAD and that genetic analysis should be provided to EOAD patients not only for the identification of their genetic causes but also for the appropriate genetic counseling.

Expression of Presenilin-2 and Glutathione S Transferase ? and Their Clinical Significance in Infiltrating Ductal Breast Carcinoma / 中国普外基础与临床杂志

Objective To investigate the expression of presenilin-2(PS2) and glutathione S transferase ?(GST?) and their role in the prognosis and therapy of infiltrating ductal breast carcinoma. Methods The expression of PS2 and GST? in tumor tissues from 210 patients with infiltrating ductal breast carcinoma confirmed by pathologic examination and treated with modified radical mastectomy was examined by using LSAB immunohistochemical method. Results The expression rate of PS2 was 49.5%(104/210) and the expression rate of GST? was 48.1%(101/210). The grade of the postoperative 5-year survival rate and 10-year survival rate in four groups of 210 patients, from high to low, was the group 1 (PS2 positive expression/GST? negative expression), the group 2 (PS2 positive expression/GST? positive expression), the group 3 (PS2 negative expression/GST? negative expression) and the group 4 (PS2 negative expression/GST? positive expression). Conclusion The prognosis of the group 1 is the best, the group 2 better, the group 3 good and the group 4 the worst. The results suggest that reasonable use of endocrinotherapy and chemotherapy in infiltrating ductal breast carcinoma is necessary.

Alzheimer's Disease and Apoptosis

Apoptosis is a form of cell death in which the cells shrink and exhibit nuclear chromatin condensation and DNA fragmentation, and yet maintain membrane integrity. Many lines of evidence have shown that brain neurons are vulnerable to degeneration by apoptosis. Also it has been suggested that apoptosis is one of the mechanism contributing neuronal loss in Alzheimer's disease(AD), since the conditions in the disease(A beta peptide, oxidative stress, low energy metabolism) are the inducers that activate apoptosis. Indeed some neurons in vulnerable regions of the AD brain show DNA damage, chromatin condensation, and apoptic bodies. Consistently, mutations in AD causative genes(Amyloid precursor protein, Presenilin-1 and Presenilin-2) increase A beta peptide1-42(Abeta1-42) and sensitize neuronal cell to apoposis. However, several lines of evidence have shown that the location of neuronal loss and A beta peptide deposition is not correlated in AD brain and transgenic mice brain over-expressing Abeta1-42. Taken together, these data may indicated that A beta peptide(and other causative factors of AD) can interact with other cellular insults or risk factors to exacerbate pathological mechansim of AD through apoptosis. Thus, this review discusses possible role and mechanism of apoptosis in AD.

Effect of LYS polysaccharides on dementia-related gene expressions in SAMP8 mouse brain / 中国药理学通报

Aim To observe the effects of LYS polysaccharides on expressions of APP, PS1, PS2 and ApoE in SAMP8 mouse brain. Methods 50 6-month-old SAMP8 mice were used and divided randomly into 5 groups: SAMP8 untreated control group, huperzine A control group, low-, mid-and high-dose groups of polysaccharides, with 10 mice in each group. 10 6-month-old SAMR1 mice were used as normal control. After each group was treated by corresponding drug for 40 days continuously, the mRNA contents of APP, PS1, PS2 and ApoE in brain tissue were assayed by reverse transcription polymerase chain reaction.Results The low-, mid-and high-dose groups of polysaccharides could reduce the mRNA contents of APP, PS1 and PS2, which showed a dose-effect relationship in some degrees. But it could not affect the content of ApoE. Conclusion LYS polysaccharides could inhibit the expressions of APP, PS1, and PS2 in SAMP8 mouse brain.