Biomedical subjects

Irina Alafuzoff

Publications and source records attributed to Irina Alafuzoff.

30 records · Page 2Linked to original sources

PubMed2004

Glycosylation changes in Alzheimer's disease as revealed by a proteomic approach.

Glycosylation influences the biological activity of proteins and affects their folding and stability. Because aberrant glycosylation is associated with Alzheimer's disease (AD), we applied proteome analysis together with Pro-Q Emerald 300 glycoprotein staining to investigate changes in glycosylated cytosolic proteins in AD and control brain. Frontal cortex proteins from 10 AD patients and 7 non-demented controls were subjected to separation by two-dimensional gel electrophoresis and subsequently stained with carbohydrate-specific Pro-Q Emerald 300 dye. Changes in glycosylation of separated proteins were quantified, and proteins of interest identified by mass spectrometry. Approximately 30% of all detectable proteins in the human frontal cortex appeared glycosylated, including heat shock cognate 71 stress protein and beta isoform of creatine kinase. The glycosylation of collapsin response mediator protein 2 (CRMP-2) and an unknown protein was reduced in AD, while the glycosylation of glial fibrillary acidic protein was increased. CRMP-2 regulates the assembly and polymerization of microtubules and is associated with neurofibrillary tangles in AD. Aberrant glycosylations in AD may help understand the mechanisms of neurodegenerative diseases.

Aged↗

PubMed2004

Prenatal diagnosis of placenta accreta and percreta with ultrasonography, color Doppler, and magnetic resonance imaging.

BACKGROUND: The risk of placenta previa and accreta is increased in females with previous cesarean deliveries, and there has been an increasing number of these operations. CASES: We present 2 cases with previous cesarean and placenta previa in the following pregnancy. One patient had placenta accreta and the other, placenta percreta. In both cases, prenatal diagnosis was based on ultrasonography, where features such as loss of the hypoechoic retroplacental zone and irregular uterine serosa were found in grayscale ultrasonography. In color Doppler imaging, in both cases, increased vascularity between myometrium and placenta, as well as intraplacental lacunae, were seen. Thinning of the uterine wall, found in magnetic resonance imaging, contributed to the diagnosis of placenta percreta. CONCLUSION: Prenatal diagnosis of placenta accreta is of importance because it reduces fetal and maternal morbidity as appropriate preoperative and perioperative procedures are possible.

Adult↗

PubMed2003

Heparan sulfate proteoglycan 2 polymorphism in Alzheimer's disease and correlation with neuropathology.

A genetic association of an intronic single nucleotide polymorphism site of heparan sulfate proteoglycan 2 (HSPG2) with Alzheimer's disease (AD) was investigated among Finnish AD patients (n=213) and controls (n=269). No association of the HSPG2 polymorphism alone was observed with AD. However, an association of HSPG2 A allele with AD was detected in apolipoprotein (APOE) epsilon4 allele carriers. The odds ratio for AD was doubled in subjects carrying both epsilon4 and HSPG2 A alleles (OR=6.6) when compared to subjects with epsilon4 allele alone (OR=3.1). The impact of HSPG2 polymorphism on beta amyloid and tau pathology was studied using immunohistochemistry. Paired helical filament labeling was significantly more pronounced in AD patients carrying both epsilon4 and HSPG A alleles when compared to epsilon4 carriers lacking the HSPG2 A allele. In conclusion, HSPG2 A allele may possess an additive risk effect among the APOE epsilon4 carriers in AD.

Adult↗

PubMed2003

Reelin-immunoreactive Cajal-Retzius cells: the entorhinal cortex in normal aging and Alzheimer's disease.

Alzheimer's disease (AD) is a disorder of brain self organization associated with morphodysregulation at the synaptic level. Disturbances follow a hierarchical spatio-temporal pattern throughout the cortex and involve the re-activation of developmental molecular programs. The large glycoprotein reelin, synthesized by Cajal-Retzius (CR) cells, is an important component of a signaling pathway involved in embryonic development and modulation of synaptic circuitry, but is also implicated in the pathogenetic cascade in AD. Although the majority of CR cells sequentially disappears from the postnatal cortical layer I, a few of them persist in the normal adult brain. They continue to produce reelin, express a variety of other proteins, and are characterized by a typical morphology. Recently, CR cells have been reported to be altered in number and morphology in a variety of neurological and psychiatric diseases linked to maldevelopment. In the present study we show that reelin-positive CR cells persist in the layer I of the entorhinal cortex in normal senescent brains and are also preserved in AD. The majority of CR cells in AD is morphologically and cytochemically-as revealed by double labeling with calcium-binding proteins-indistinguishable from normal cases, suggesting that they are not dramatically altered in the entorhinal cortex of AD patients. Nevertheless, CR cells seem to be partially affected by the formation of paired helical filaments, indicating subtle changes that are suggested to be a result rather than a cause of the pathogenetic cascade of AD.

Aged↗

PubMed2003

Absence of association between an intercellular adhesion molecule 1 gene E469K polymorphism and Alzheimer's disease in Finnish patients.

Increased expression of intercellular adhesion molecule 1 (ICAM1), a protein known to contribute to inflammatory responses, has been detected in the brain tissue of patients with Alzheimer's disease (AD) and animals modelled to mimic AD or Parkinson's disease (PD). ICAM1 may, thus, be implicated in the pathogenesis of these disorders. Our purpose was to investigate whether genetic variants of the ICAM1 gene have a role in causing susceptibility to AD and/or PD. We genotyped the E469K polymorphism of ICAM1 in 196 AD, 52 PD and 202 control patients of Finnish origin. The distributions of the genotype and allele frequencies of the polymorphism did not differ significantly between the AD, PD or the control patients. We therefore conclude that the E469K polymorphism of ICAM1 is not a risk factor for AD or PD.

Alzheimer Disease↗

PubMed2003

Up-regulation of phosphorylated/activated p70 S6 kinase and its relationship to neurofibrillary pathology in Alzheimer's disease.

The ribosomal S6 protein kinase p70 S6 kinase is known for its role in modulating cell-cycle progression, cell size, and cell survival. In response to mitogen stimulation, p70 S6 kinase activation up-regulates ribosomal biosynthesis and enhances the translational capacity of the cell. In Alzheimer's disease (AD), there is a marked increase in total tau protein in the form of abnormally hyperphosphorylated tau (PHF-tau) in neurons with neurofibrillary tangles (NFTs). In the present study, we investigated whether p70 S6 kinase activation is associated with PHF-tau accumulation in AD. By immunohistochemistry, we found that the levels of phosphorylated p70 S6 kinase (at Thr389 or at Thr421/Ser424) were increased in accordance with the progressive sequence of neurofibrillary changes according to Braak's criteria. Confocal microscopy showed that in AD brain, phosphorylated p70 S6 kinase appeared especially in neurons that are known to later develop NFTs. This pattern of neurons showed dot-like structures of phosphorylated p70 S6 kinase and hyperphosphorylated tau, which partially correlated with rab5 (endosome marker), lamp-1 (lysosome marker), and ubiquitin (ubiquitin-proteasomal system marker). By indirect enzyme-linked immunosorbent assay, phosphorylated p70 S6 kinase (Thr389 or Thr421/Ser424), total tau, and PHF-tau were found to be significantly increased in AD brain as compared to control cases. The levels of total p70 S6 kinase and p70 S6 kinase phosphorylated at Thr421/Ser424 showed significant correlations with the levels of both total tau and PHF-tau. Regression analyses revealed a significant dependence of total tau or PHF-tau on p70 S6 kinase phosphorylated at Thr421/Ser424 rather than at Thr389. The levels of ribosomal protein S6 as well as the levels of markers for the proteolytic system were also significantly increased in AD as compared to control brain. Using a SH-SY5Y neuroblastoma cell model, we found that 100 micro mol/L zinc sulfate could induce p70 S6 kinase phosphorylation and activation, in particular at Thr421/Ser424. This up-regulation of the activated kinase resulted in an increased expression and phosphorylation of tau. Pretreatment of cells with rapamycin (an inhibitor of FRAP/mTOR which is the immediate upstream kinase of the p70 S6 kinase) attenuated the effects induced by zinc. In primary cultured neurons of rat cortical cortex, zinc sulfate treatment could repeat p70 S6 kinase phosphorylation and activation at Thr421/Ser424, followed by increased expression and phosphorylation of tau. Taken together, these data suggest that activated p70 S6 kinase could mediate an up-regulation of tau translation. The partial co-localization of phosphorylated p70 S6 kinase with rab5, lamp-1 and ubiquitin, or PHF-tau with ubiquitin suggests that the activated proteolytic system might not be sufficient to degrade the over-produced and over-phosphorylated tau protein. A p70 S6 kinase modulated up-regulation of tau translation might contribute to PHF-tau accumulation in neurons with neurofibrillary changes.

Aged↗

PubMed2003

Morphogenesis of Lewy bodies: dissimilar incorporation of alpha-synuclein, ubiquitin, and p62.

The formation of Lewy bodies (LBs) and their relationship to other types of nigral inclusions associated with Parkinson disease (PD), such as pale bodies (PBs), remain poorly understood. Known constituents of LBs include alpha-synuclein (alphaS) and ubiquitin (Ub), providing windows to their morphogenesis. Additionally, p62/sequestosome 1 has been identified as a common component of neuropathological and hepatocytic inclusions. To study the formation of PD-associated nigral inclusions, we analyzed the substantia nigra of cases with abundant LBs and PBs in hematoxylin and eosin (H&E) stain, using immunohistochemistry for alphaS, Ub, and p62. We found morphologically diverse alphaS-immunoreactive deposits within neuronal perikarya and neurites. Perikaryal types extended from punctate cytoplasmic staining to variform compact (i.e. PB-type and LB-type) inclusions. Using H&E, only a small subset of the compact deposits could be unambiguously identified. Labeling for p62 was highly similar to alphaS in compact perikaryal inclusions, whereas no punctate staining or intraneuritic inclusions were detected. Ubiquitin antibodies labeled compact deposits both within perikarya and neurites. The data suggest that pathological alphaS is first evident as punctate perikaryal material that, via coalescence and incorporation of p62 and Ub, yields PB-type structures from which LB-type inclusions form in a compaction-like manner. The results also point at dissimilarities in the formation of perikaryal vs intraneuritic inclusions.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Regional distribution of alpha-synuclein pathology in unimpaired aging and Alzheimer disease.

The amygdaloid complex (AC) was found highly vulnerable to alpha-synuclein (alphaS) pathology in both familial and sporadic Alzheimer disease (AD), and recently, incidental Lewy bodies (LBs) were identified primarily in the lower brainstem. This challenges the traditional view that the substantia nigra (SN) is the region that is predominately affected in the spectrum of LB disorders. We examined the immunoreactivity of alphaS in the SN, the nucleus basalis of Meynert (nbM), and the AC in 904 subjects with or without concomitant AD pathology. AlphaS-positive structures were seen in at least one of the studied brain areas in 121 subjects (13%). The affected regions in the alphaS-positive subjects included the SN (89%), the nbM (73%), and the AC (67%). This study also included 82 sporadic AD patients diagnosed using CERAD criteria. AlphaS-positive structures were seen in 32% of the AD patients, with the SN and AC being equally affected. In a few subjects the AC was the only affected area. However, this was not inevitably associated with AD pathology, but was related to cognitive decline. Incidental LBs in the SN were described in the occasional subjects, with no alphaS pathology in the lower brainstem.

Adult↗

PubMed2002

Role of protein kinase B in Alzheimer's neurofibrillary pathology.

Protein kinase B (PKB) is an important intermediate in the phosphatidylinositol-3 kinase signaling cascade that acts to phosphorylate glycogen synthase kinase-3 (GSK-3) at its serine 9 residue, thereby inactivating it. Activated GSK-3 has been previously shown to be preferentially associated with neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) brain. In the present study, we performed immunohistochemistry with an antibody to the active form of PKB in brains with different stages of neurofibrillary degeneration. We found that the amount of activated PKB (p-Thr308) increased in correlation to the progressive sequence of AT8 immunoreactivity and neurofibrillary changes assessed according to Braak's criteria. By confocal microscopy, activated PKB (p-Thr308) was found to appear in particular in neurons that are known to later develop NFTs in AD. Western blotting showed that activated PKB was increased by more than 50% in the 16,000- g supernatants of AD brains as compared with normal aged and Huntington's disease controls. This increase in PKB levels corresponded with a several-fold increase in the levels of total tau and abnormally hyperphosphorylated tau at the Tau-1 site. These studies suggest the involvement of PKB/GSK-3 signaling in Alzheimer neurofibrillary degeneration.

Adult↗

PubMed2002

Proteomic analysis of protein oxidation in Alzheimer's disease brain.

There is a growing body of evidence that oxidative stress plays a major role in Alzheimer's disease (AD) pathogenesis. Identification of oxidatively altered proteins in AD is important for understanding the relationship between protein oxidation, protein aggregation and neurodegeneration. In this communication, we report a method that can be applied to study oxidative changes of individual proteins in brain. In order to analyze protein oxidation by detection of protein-bound carbonyls, cytosolic protein extracts were derivatized with 2,4-dinitrophenylhydrazine (DNPH) and then separated by two-dimensional (2-D) gel electrophoresis. After electrotransfer to polyvinylidene difluoride (PVDF) membranes, proteins were first stained with Sypro Ruby protein stain, and then the oxidized proteins were detected with anti-dinitrophenyl (DNP) antibody. About 150 proteins and more than 100 oxidized proteins were detected and quantified in both AD and control cases by 2-D image analysis. The amount of protein-bound carbonyls was decreased for six and increased for one protein in AD. The amount of protein was increased for three proteins in AD. Furthermore, the degree of oxidation was calculated as the ratio of protein-bound carbonyls to the total amount of an individual protein. Two proteins showed a significant decrease in the degree of oxidation in AD. Our results suggest that the balance of protein oxidation and degradation is altered in AD.

Aged↗

PubMed2002

Interleukin 1 alpha gene polymorphism as a susceptibility factor in Alzheimer's disease and its influence on the extent of histopathological hallmark lesions of Alzheimer's disease.

We investigated the association of the interleukin 1alpha (IL1A) (-889) C/T polymorphism with Alzheimer's disease (AD) and with the extent of AD histopathological lesions, the senile/neuritic plaques (SPs/NPs) and neurofibrillary tangles. We evaluated 98 neuropathologically confirmed AD patients and 240 controls as well as 146 clinically diagnosed AD patients and 278 controls but found no association of the IL1A C/T polymorphism with AD even after adjustment for the apolipoprotein E (APOE) genotype, gender or age. The extents of AD histopathological lesions were not influenced by the IL1A genotype except after exclusion of the APOE epsilon4 allele, when a trend towards more SPs/NPs was observed in AD patients with the IL1A C/C compared to patients with the T/T genotype. These results do not confirm previous studies which have indicated that the IL1A C/T polymorphism is a susceptibility factor for AD. However, the IL1A C/C genotype might be associated with the progression of SPs/NPs in AD patients, but the effect is weak and obscured by the APOE epsilon4 allele.

Aged↗

PubMed2000

Lower Counts of Astroglia and Activated Microglia in Patients with Alzheimer's Disease with Regular Use of Non-Steroidal Anti-Inflammatory Drugs.

Epidemiological studies have indicated that non-steroidal anti-inflammatory drugs (NSAID) may have some therapeutic effect in Alzheimer's disease (AD) and experimental studies have shown that microglia activation by Abeta-peptide (Abeta-peptide. Furthermore, our results indicate that regular NSAID use is associated with significantly lower counts of astrocytes and a trend of lower counts of activated microglia in the brain tissue. The influence of NSAID use was noted in all ApoE genotypes however the trend of lower counts of glial cells with regular NSAID use was more marked in patients carrying the ApoE varepsilon 4/4 alleles. Based on our results one would anticipate that regular NSAID dosing could have a beneficial effect on the progression of the disease. However, the fact that we failed to observe significant differences for activated microglia might indicate an age or stage dependent difference in the glial response i.e. in their activation rate. More studies into age and stage related factors influencing the glial response are required if one is to devise novel pharmacological treatment strategies for AD.

Journal Article↗