Selective hippocampal neurodegeneration in transgenic mice expressing small amounts of truncated Aβ is induced by pyroglutamate-Aβ formation

Posttranslational amyloid-β (Aβ) modification is considered to play an important role in Alzheimer's disease (AD) etiology. An N-terminally modified Aβ species, pyroglutamate-amyloid-β (pE3-Aβ), has been described as a major constituent of Aβ deposits specific to human AD but absent in normal aging. Formed via cyclization of truncated Aβ species by glutaminyl cyclase (QC; QPCT) and/or its isoenzyme (isoQC; QPCTL), pE3-Aβ aggregates rapidly and is known to seed additional Aβ aggregation. To directly investigate pE3-Aβ toxicity in vivo, we generated and characterized transgenic TBA2.1 and TBA2.2 mice, which express truncated mutant human Aβ. Along with a rapidly developing behavioral phenotype, these mice showed progressively accumulating Aβ and pE3-Aβ deposits in brain regions of neuronal loss, impaired long-term potentiation, microglial activation, and astrocytosis. Illustrating a threshold for pE3-Aβ neurotoxicity, this phenotype was not found in heterozygous animals but in homozygous TBA2.1 or double-heterozygous TBA2.1/2.2 animals only. A significant amount of pE3-Aβ formation was shown to be QC-dependent, because crossbreeding of TBA2.1 with QC knock-out, but not isoQC knock-out, mice significantly reduced pE3-Aβ levels. Hence, lowering the rate of QC-dependent posttranslational pE3-Aβ formation can, in turn, lower the amount of neurotoxic Aβ species in AD.     

Fatigue, depressive symptoms, and anxiety from adolescence up to young adulthood: a longitudinal study

Fatigue is a common complaint among adolescents. We investigated the course of fatigue in females during the transition from adolescence to young adulthood and examined psychological, immunological, and life style risk factors for development of fatigue and chronic fatigue syndrome (CFS)-related symptoms. Six hundred and thirty-three healthy females (age 14.63 ± 1.37 years) filled out questionnaires measuring fatigue severity, depressive symptoms, anxiety, chronic fatigue syndrome (CFS)-related symptoms, sleep features, and life style characteristics at baseline and 4½ years thereafter. Of 64 participants LPS- and CD2CD28-induced cytokine data at baseline were available. The best predictor of fatigue in young adulthood was previous fatigue severity. In participants who were non-fatigued during adolescence and who experienced a notable increase in fatigue, fatigue development was preceded by emotional problems and CFS-related complaints during adolescence. Increases as well as decreases in fatigue severity were accompanied by respectively increase and decrease in depressive symptoms and anxiety, suggesting that these symptoms cluster and co-vary over time. Higher interferon (IFN)-γ, higher IFN-γ/interleukin (IL)-4 ratio, lower tumor necrosis factor-α and lower IL-10 at baseline were related to fatigue severity at follow up. The rise in total number of CFS-related symptoms at follow up was predicted by anxiety and decreased physical activity during adolescence. Sleep and substance use were associated with fatigue severity and anxiety and depression. In conclusion, vulnerability to develop fatigue and associated symptoms in young adulthood can to a certain extent be identified already years before the manifestation of complaints.     

Which compartments are involved in Philadelphia-chromosome positive chronic myeloid leukaemia? An answer at the single cell level by combining May-Grünwald-Giemsa staining and fluorescence in situ hybridization techniques

Chronic myeloid leukaemia (CML) is believed to represent a stem cell disorder involving all three cell lineages. The typical chromosomal aberration, the Philadelphia chromosome, is the translocation (9;22)(q34;q11). Several studies with cytogenetics, fluorescence in situ hybridization (FISH), or polymerase chain reaction have investigated the presence of the t(9;22) in different cell compartments. However, questions still remain. In six cases of CML we combined the standard May-Grünwald-Giemsa staining with FISH at the single-cell level and were able to demonstrate that not only all maturation stages of granulopoiesis, erythropoiesis, and megakaryocytes, but also plasma cells, eosinophils, basophils and monocytes carried the Philadelphia chromosome in 53–98% of samples. Using immunological identification of single cells we were able to demonstrate that the t(9;22) is detectable in 34% of CD3-positive T lymphocytes, in 32% of CD19-positive B lymphocytes, and in 82% of CD34-positive precursor cells. The results give new insight into the biology of CML and may have implications for future therapeutic strategies.     

Molecular Pathology and Structural Features of Enteroviral Replication Toward Understanding the Pathogenesis of Viral Heart Disease

Enteroviruses of the Picornaviridae and primarily coxsackieviruses of group B (CVB) can be detected in humans and various experimental murine models of acute myocarditis and chronic heart muscle diseases indicating enterovirus persistence in the myocardium. Persistent myocardial infection is characterized by restricted viral replication and gene expression in myocytes capable of sustaining chronic inflammation. Viral cytotoxicity was found to be crucial for organ pathology both during acute and persistent infection. In-situ hybridization experiments at the cellular and subcellular level have demonstraged that virus replication is associated with severe structural changes of the cardiomyocyte cytoarchitecture at any stage of the disease. In tissue culture experiments and transgenic mice, it was shown that restricted replication and gene expression of the virus are capable of inducing myocytopathic effects. Investigations at the molecular level revealed that interference of coxsackievirus replication with the cellular metabolism is mediated by cleavage of host cell proteins by virus-encoded proteinases. Notably, there is also evidence that enteroviruses are able to activate specific cellular signal transduction pathways in the course of infection, thus promoting enteroviral replication. In summary, these data indicate that mutural influences of virus replication and subsequent modifications of the host cell metabolism are crucial for cardiac injury and dysfunction during acute and chronic disease. Zusammenfassung Enteroviren aus der Familie der Picornaviridae, insbesondere Coxsackieviren der Gruppe B, können durch molekularbiologische Untersuchungsverfahren wie In-situ-Hybridisierung und Polymerasekettenreaktion, nicht nur bei akuter, sondern auch bei chronischer Myokarditis nachgewiesen werden als Beleg für die mögliche Persistenz von Enteroviren im humanen Myokard. Das pathogenetische Konzept der akuten und persistierenden Enterovirusinfektion und damit assoziierter Herzmuskelerkrankungen wird unterstützt durch Befunde in verschiedenen Modellsystemen der murinen Myokarditis, die zeigen, dass Coxsackie-Viren bei immunkompetenten Mäusen eine akute und chronische Myokarditis induzieren können. Die persistierende Infektion im Myokard ist hierbei charakterisiert durch restringierte, in der Regel nichtlytische Virusreplikation, wobei es im Gegensatz zur akuten Infektion nicht zur Eliminierung infizierter Zellen kommt. Im Rahmen der Analyse von Interaktionen viraler und wirtsspezifischer Faktoren konnte durch licht- und elektronenmikroskopische In-situ-Hybridisierung gezeigt werden, dass die zu jedem Zeitpunkt der Infektion beobachteten zytotoxischen Effekte in infizierten Myozyten eng mit Virusreplikation assoziiert sind. Die Bedeutung der viralen Replikation für die Pathogenese der myokardialen Schädigung wird zudem belegt durch Untersuchungen an kultivierten Myozyten sowie an transgenen Tieren, die zeigen, dass auch in Abwesenheit infektiöser Viren die restringierte virale Genexpression mit dem Myozytenstoffwechsel interferiert und hierdurch pathogen wirkt. Hinsichtlich der Regulation der viralen Replikation in enterovirusinfizierten Zellen gibt es Hinweise dafür, dass diese durch Aktivierung spezifischer zellulärer Signaltransduktionswege moduliert werden kann. Zusammenfassend weisen diese Untersuchungen darauf hin, dass sowohl die Virusreplikation als auch die daraus resultierenden Veränderungen im Wirtszellstoffwechsel zu einer Dysfunktion des Herzmuskels beitragen.     

Knowledge, attitudes towards and acceptability of genetic modification in Germany

Genetic modification remains a controversial issue. The aim of this study is to analyse the attitudes towards genetic modification, the knowledge about it and its acceptability in different application areas among German consumers. Results are based on a survey from spring 2005. An exploratory factor analysis is conducted to identify the attitudes towards genetic modification. The identified factors are used in a cluster analysis that identified a cluster of supporters, of opponents and a group of indifferent consumers. Respondents' knowledge of genetics and biotechnology differs among the found clusters without revealing a clear relationship between knowledge and support of genetic modification. The acceptability of genetic modification varies by application area and cluster, and genetically modified non-food products are more widely accepted than food products. The perception of personal health risks has high explanatory power for attitudes and acceptability.     

Promoter hypermethylation of the 14-3-3 sigma, SYK and CAGE-1 genes is related to the various phenotypes of urinary bladder carcinomas and associated with progression of transitional cell carcinomas

To explore the significance of epigenetic mechanisms in urinary bladder carcinogenesis mediated by methylation of cytosine in CpG dinucleotides at 5' promoter regions, we analysed the methylation status of a broad panel of different genes in transitional cell carcinomas (TCC) and nonurothelial cancers, among which the 14-3-3 sigma, SYK and CAGE-1 genes were recognised as promising target genes. Using methylation-specific PCR, the rate of DNA hypermethylation proved to be related to the various histopathological cancer subtypes. The higher frequency of promoter methylation of the 14-3-3 sigma (57.1%) and SYK (64.3%) genes in high-grade, high-stage TCC in association with a reduced or even lacking immunohistochemical protein expression than in low-grade, low-stage TCC (28.6% and 42.9%, respectively), indicates that aberrant methylation of these genes plays an essential role in the progression of TCC. The importance of DNA hypermethylation in the conversion of TCC from a low to a high malignant potential was strongly supported by the finding that, unlike superficial low-grade TCC, advanced muscle invasive TCC showed a concurrent promoter methylation of the 14-3-3 sigma, SYK and CAGE-1 genes. Squamous cell carcinomas revealed a peak incidence of hypermethylation of the 14-3-3 sigma gene (80%), and conversely, the lowest methylation frequency of the SYK gene (13.3%). Undifferentiated small cell carcinomas disclosed a promoter methylation of the 14-3-3 sigma, SYK and CAGE-1 genes in only a quarter each for the cases. Although a correlation between the methylation status and gene activity in squamous cell and undifferentiated small cell carcinomas was not observed, the underexpression of the SYK protein products in both cancer types and additionally of the 14-3-3 sigma protein in small cell carcinomas appeared to be related to the aggressive clinical behaviour of both these nonurothelial bladder carcinomas. The relevance of the high frequency of DNA hypermethylation of the CAGE-1 antigen in TCC and squamous cell carcinomas merits further study, particularly in relation to anticancer immunotherapy. The methylation status of the PTEN, COX-2, RUNX-3 and HIC-1 genes was found to be unaltered. In conclusion, the different patterns of aberrant methylation of the 14-3-3 sigma, SYK and CAGE-1 genes in the various histopathological cancer types of the urinary bladder point to a role in tumor cell differentiation, resulting in the phenotypical conversion of TCC into nonurothelial carcinomas and in the progression of TCC to a more malignant potential.