Der Einfluss von Vitamin D und seinen Analoga auf die in der Alzheimer-Demenz relevante Aβ-Homöostase

Die neurodegenerative Erkrankung Morbus Alzheimer gewinnt aufgrund ihrer steigenden Prävalenz zunehmend an klinischer, sozialer und wirtschaftlicher Relevanz. Eine krankheitsmodifizierende Therapie ist in Europa bis jetzt nicht zugelassen. Als potenzieller Therapieansatz gilt die Reduktion der histopathologisch vermehrt nachweisbaren amyloiden Plaques. Obwohl Vitamin D auf molekularer Ebene in die Entstehung und den Abbau des Amyloid-β Peptides (Aβ), dem Hauptbestandteil der amyloiden Plaques, eingreift, zeigen epidemiologischen Studien bisher keinen ausreichenden therapeutischen Nutzen einer Vitamin D Supplementierung in Bezug auf die Reduktion des Alzheimerrisikos. In vielen medizinischen Bereichen werden synthetische Vitamin D Analoga eingesetzt, die veränderte Wirkungs- und Nebenwirkungsprofile mitbringen. Ziel der vorliegenden Arbeit war daher die systematische Untersuchung molekularer Mechanismen ausgewählter Vitamin D Analoga auf die in der Pathologie von Morbus Alzheimer relevante Aβ-Homöostase sowie auf Entzündungsparameter am Beispiel von Interleukin-1β. In Zellkulturen und murinen Hirnproben wurden die Effekte einer Inkubation der Vitamin D2 Analoga Paricalcitol und Doxercalciferol und der Vitamin D3 Analoga Maxacalcitol, Calcipotriol und Alfacalcidol auf die Genexpression, Sekretase Aktivität und die Proteinebene unterschiedlicher Enzyme analysiert, die an der Aβ-Produktion und Degradation beteiligt sind. Die Effektstärken wurden mit Ethanol als Lösungsmittelkontrolle und mit natürlich vorkommenden Calcifediol verglichen. Die Vitamin D Analoga reduzierten im Vergleich zur Lösungsmittelkontrolle in humanen Neuroblastomzellen das Aβ-Gesamtlevel, was einerseits auf inhibierende Effekte auf die an der Aβ-Produktion beteiligten β- und γ-Sekretasen, andererseits auf einen erhöhten Aβ-Abbau durch das Enzym Neprilysin zurückgeführt werden konnte. Neben Einflüssen auf die Aktivität dieser Enzyme, regulierte die Inkubation der Vitamin D Analoga auch die Genexpression. Paricalcitol erhöhte zudem die α-Sekretase Aktivität, durch die das Amyloid-Vorläuferprotein, aus dem Aβ durch proteolytische Spaltung entsteht, alternativ in Form einer nicht-amyloidogenen Prozessierung zersetzt wird. Hierdurch wird die Entstehung von Aβ verhindert. Darüber hinaus wurde das Interleukin-1β-Level durch alle Vitamin D Analoga außer Paricalcitol signifikant gesenkt, sodass auch eine Regulation inflammatorischer Prozesse gezeigt wurde. Die Effektstärken der untersuchten Vitamin D Analoga unterschieden sich hierbei untereinander und in Bezug zu Calcifediol nicht signifikant. Vitamin D und seine Analoga interagierten mit der β-Sekretase Aktivität und der Aβ-Degradation sowohl in Hirnproben von Wildtypmäusen als auch in Hirnproben von Mäusen, in denen zuvor eine Hypovitaminose D generiert wurde. Die Ergebnisse untermauern den Zusammenhang zwischen Morbus Alzheimer und Vitamin D und deuten darauf hin, dass eine Supplementierung von Vitamin D oder Vitamin D Analoga einen präventiven und therapeutischen Nutzen bei Morbus Alzheimer haben könnte.1.2 The influence of vitamin D and its analogues on the Ab-homeostasis relevant in Alzheimer’s disease The neurodegenerative Alzheimer's disease is gaining increasing clinical, social and economic relevance due to its rising prevalence. A disease-modifying therapy has not yet been approved in Europe. A potential therapeutic approach is the reduction of the histopathological increased detectable amyloid plaques. Although vitamin D intervenes at the molecular level in the formation and degradation of amyloid (Aβ), which is the main component of amyloid plaques, epidemiological studies have not yet shown sufficient therapeutic benefit of vitamin D supplementation in terms of reducing the risk of Alzheimer's disease. In many medical fields, vitamin D analogues are used, which bring altered efficacy and side effect profiles. Therefore, the aim of the present study was to systematically investigate molecular mechanisms of selected vitamin D analogues on Ab-homeostasis, which is relevant in the pathology of AD, and on inflammatory parameters using interleukin-1b-level as an example. In cell cultures and examples of mouse brains, the effects of incubation of the vitamin D2 analogues paricalcitol and doxercalciferol and the vitamin D3 analogues maxacalcitol, calcipotriol, and alfacalcidol on gene expression, secretase activity, and protein levels of different enzymes involved in Aβ-production and degradation were analyzed. Effect sizes were compared with ethanol as a solvent control and with naturally occurring calcifediol. The vitamin D analogues reduced total Aβ-levels in human neuroblastoma cells, which could be attributed on the one hand to inhibitory effects on the β- and g-secretases involved in Aβ- production and on the other hand to increase Aβ-degradation by the enzyme neprilysin. In addition to influences on the activity of these enzymes, incubation of vitamin D analogues also regulated gene expression. Paricalcitol also increased a-secretase activity, by which the amyloid precursor protein, from which Aβ is generated by proteolytic cleavage, is alternatively decomposed in the sense of nonamyloidogenic processing. This prevents the formation of Aβ. In addition, interleukin-1β-level was significantly decreased by all vitamin D analogues except paricalcitol, so regulation of inflammatory processes was also shown. The effect sizes of the investigated vitamin D analogues did not differ significantly among each other and in relation to calcifediol. Vitamin D and analogues interacted with β-secretase activity and Aβ-degradation both in brain samples from wild-type mice and in brain samples from mice in which hypovitaminosis D had been previously generated. The results support the link between Alzheimer's disease and vitamin D and suggest that supplementation of vitamin D or vitamin D analogues may have preventive and therapeutic benefits in Alzheimer's disease

Aktuelle Ergebnisse zur Feintypisierung von Salmonella Typhimurium aus Hackfleisch

Current results on the detailed typing of Salmonella Typhimurium from minced meat. The aim of the study was to use PFGE to analyse salmonella isolates from samples of minced meat taken from an EU-approved abattoir and meat processing facility in the period from January 2002 to January 2004. The results were compared with data from previous analyses. Of the total of 350 minced meat samples examined, 36 tested positive for salmonella (10.3 %). The evaluation showed an increase in the number of samples testing positive for salmonella in both summer and winter months. It was remarkable that the samples which most frequently tested positive came from minced meat produced on Tuesdays and Fridays. Detailed typing of the isolates using PFGE was modified and optimised. Only S. Typhimurium and S. Typhimurium var. Copenhagen were examined, as these serovars had been most frequently isolated (51.4 % and 25.7 % respectively), and have a prominent role to play in terms of epidemiology. The macrorestriction enzymes Xba I and Spe I were used. The results following restriction using Xba I were compared with those from previous analyses. Restriction of all isolates using Spe I served to verify the results. Six different restriction patterns were found using Xba I; the majority of the isolates (87.5 %) could be classified in three groups. A comparison with the results from previous analyses showed that two of the groups had been discovered in the minced meat samples of the same facility since 1996. The third group was discovered for the first time in the course of this study. The fact that salmonella isolates with identical macrorestriction patterns have been found in minced meat samples of a production facility over a period of seven years points to a persistent source of contamination which normal hygiene measures have been unable to pick up. Consumer protection would be considerably improved if this source could be detected and eliminated.Ziel der vorliegenden Arbeit war es, Salmonellen-Isolate aus Hackfleischproben eines EU-zugelassenen Schlacht- und Zerlegebetriebes des Untersuchungszeitraumes Januar 2002 bis Januar 2004 mittels PFGE feinzudifferenzieren. Die Ergebnisse wurden mit Daten vorangegangener Untersuchungen verglichen. Von insgesamt 350 geprüften Hackfleischproben waren 36 Salmonellen-positiv (10,3 %). Die Auswertung zeigte einen Anstieg Salmonellen-positiver Proben sowohl in den Sommer- wie auch in den Wintermonaten. Auffällig war, dass Proben der Hackfleischproduktionstage Dienstag und Freitag am häufigsten Salmonellen-positiv waren. Die Feintypisierung der lsolate mit PFGE wurde modifiziert und optimiert. Dabei wurden ausschließlich S. Typhimurium und S. Typhimurium var. Copenhagen geprüft, da diese Serovare mit 51,4 % bzw. 25,7 % am häufigsten isoliert worden waren und epidemiologisch eine herausragende Rolle spielen. Zum Einsatz kamen die Makrorestriktionsenzyme Xba I und Spe I. Die Ergebnisse nach Restriktion mit Xba I wurden mit denen vorangegangener Untersuchungen verglichen. Die Restriktion aller Isolate mit Spe I diente der Ergebnisüberprüfung. Mit Xba I wurden sechs verschiedene Restriktionsmuster gefunden; die meisten Isolate (87,5 %) konnten in drei Gruppen eingeordnet werden. Ein Vergleich mit den Ergebnissen vorangegangener Untersuchungen ergab, dass zwei der Gruppen kontinuierlich seit 1996 in den Hackfleischproben des gleichen Betriebs nachgewiesen wurden. Die dritte Gruppe wurde im Rahmen dieser Arbeit erstmals entdeckt. Die Tatsache, dass Salmonellen-Isolate mit identischen Makrorestriktionsmustern über sieben Jahre hinweg in Hackfleischproben eines Produktionsbetriebs vorkommen, weist auf eine ständige, durch übliche Hygienemaßnahmen nicht zu erfassende Kontaminationsquelle hin. Wenn diese entdeckt und ausgeschaltet werden könnte, wäre das ein erheblicher Fortschritt für den Schutz des Verbrauchers

Kiloniella laminariae, gen. nov., sp. nov., a new alphaproteobacterium from the marine macroalga Laminaria saccharina

A novel alphaproteobacterium, strain LD81(T), was isolated from the marine macroalga. Laminaria saccharina. The bacterium is mesophilic and shows a typical marine growth response. It is a chemoheterotrophic aerobe with the potential for denitrification. Growth optima are 25 degrees C, pH 5.5 and 3% NaCl. Strain LD81(T) has a unique phylogenetic position, not fitting any of the known families of the Alphaproteobacteria. The 16S rRNA gene sequence revealed a distant relationship to species of several orders of the Alphaproteobacteria, with less than 90% sequence similarity. Phylogenetically, strain LD81(T) is related to the type strains of Terasakiella pusilla (88.4% 16S rRNA gene sequence similarity) and the three Thalassospira species (88.9-89.2%. It forms a cluster with these bacteria and a novel as-yet undescribed isolate (KOPRI 13522; 96.6% sequence similarity). Strain LD81(T) has a relatively low DNA G + C content (51.1 mol%) and, due to its distant phylogenetic position from all other alphaprotecibacteria, strain LD81(T) (=NCIMB 14374(T) =JCM 14845(T)) is considered as the type strain of a novel species within a new genus, for which the name Kiloniella laminariae gen. nov., sp. nov. is proposed. The genus Kiloniella represents the type of the new family Kiloniellaceae fam. nov. and order Kiloniellales ord. nov

Attitude of European car drivers towards electric vehicles: a survey

CO2 emissions from road transport have risen significantly in the past and projections show that they will continue to rise in the future if no adequate policy measures are implemented. Several European initiatives aim at reducing CO2 emissions from passenger vehicles. A potential option to reduce passenger vehicle CO2 emissions is the deployment of electric vehicles (EV). Consumer perception and willingness to purchase these new vehicle technologies lies at the heart of its successful large scale diffusion. This report aims at describing and analyzing how car drivers in the six countries France, Germany, Italy, Poland, Spain, and United Kingdom consider electric cars, how familiar they are with the electric car concept and its main features. It investigates, which features of EVs people consider essential in terms of propensity to consider electric cars a realistic alternative in case they wanted to purchase a new car. 600 drivers on average per each of the six Member States responded to the questionnaire. As a result we derive an “ideal” composition of an electric car in terms of car purchase price, range, re-charge time and maximum speed. The perspective of the European car drivers, as derived from this study, highlights the importance of further R&D investments to improve some of the performance characteristics of electric vehicles. It provides some guidance which performance aspects matter most for car drivers, notably costs and range. The study finds that the familiarity of car drivers with the electric vehicle aspects is lower when direct exposure or driving experience would be needed to properly assess these aspects. This stresses the need of demonstration activities in order to increase public awareness of electro-mobility and also to receive first hand feedback from car drivers on their experience operating an electric vehicle. A majority of the respondents considers that public incentives are needed to foster a wider market deployment of electric vehicles. Furthermore the study shows that an adequate re-charge network is perceived as crucial by car drivers. It can be concluded that European car drivers see the opportunities that electric vehicles could offer but that a number of pre-requisites need to be fulfilled in order to ensure that the car drivers can consider electric vehicles as a credible vehicle choice.JRC.F.6-Energy systems evaluatio

Transient receptor potential melastatin-3 (TRPM3)-induced activation of AP-1 requires Ca 2+ ions and the transcription factors c-Jun, ATF2, and TCF

Abbreviations: AP-1, activator protein-1; bZIP, basic region leucine zipper; MAP kinase, mitogen activated protein kinase; PKC, protein kinase C; SRE, serum response element; SRF, serum response factor; TRE, 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive element; TRP, transient MOL #95695

Ephrin-B2 expression critically influences Nipah virus infection independent of its cytoplasmic tail

<p>Abstract</p> <p>Background</p> <p>Cell entry and cell-to-cell spread of the highly pathogenic Nipah virus (NiV) requires binding of the NiV G protein to cellular ephrin receptors and subsequent NiV F-mediated fusion. Since expression levels of the main NiV entry receptor ephrin-B2 (EB2) are highly regulated <it>in vivo </it>to fulfill the physiological functions in axon guidance and angiogenesis, the goal of this study was to determine if changes in the EB2 expression influence NiV infection.</p> <p>Results</p> <p>Surprisingly, transfection of increasing EB2 plasmid concentrations reduced cell-to-cell fusion both in cells expressing the NiV glycoproteins and in cells infected with NiV. This effect was attributed to the downregulation of the NiV glycoproteins from the cell surface. In addition to the influence on cell-to-cell fusion, increased EB2 expression significantly reduced the total amount of NiV-infected cells, thus interfered with virus entry. To determine if the negative effect of elevated EB2 expression on virus entry is a result of an increased EB2 signaling, receptor function of a tail-truncated and therefore signaling-defective ΔcEB2 was tested. Interestingly, ΔcEB2 fully functioned as NiV entry and fusion receptor, and overexpression also interfered with virus replication.</p> <p>Conclusion</p> <p>Our findings clearly show that EB2 signaling does not account for the striking negative impact of elevated receptor expression on NiV infection, but rather that the ratio between the NiV envelope glycoproteins and surface receptors critically influence cell-to-cell fusion and virus entry.</p

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD

Driving and parking patterns of European car drivers – a mobility survey

The development of innovative vehicles such as electric driven cars is an important potential option for improving the sustainability of the transport sector. A significant penetration of electric vehicles in the market is possible only if their use is compatible with mobility patterns of individuals. For instance, the driven distance should be compatible with the batteries range or parking patterns should enable re-charging. The JRC-IET together with TRT and IPSOS analyzed car mobility patterns derived from direct surveys in six European Union Member States (France, Germany, Italy, Poland, Spain and United Kingdom). The report aims at providing some insights on how electric vehicles could fit mobility habits of European car drivers. The analysis is based on the data collected within six European countries by means of a sample survey. A web-based car trips diary was filled in by on average 600 individuals in each country. The individuals logged for 7 consecutive days their driving and parking patterns in 5 minute intervals. For each trip several details such as departure and arrival time, distance and parking place were registered. Socioeconomic characteristics of individuals were also collected. The same questionnaire format was used in all countries allowing for comparability of responses. Representativeness of the derived data was ensured by weighting and aligning the received sample to the socio-demographic reference universe of each member state. Survey results are statistically analyzed to describe mobility patterns. In particular, the information on average number of car trips per day, daily travel distance, daily travel time, trip distance, distribution of parking and driving, distribution of parking places, trip purposes, duration of parking and many other parameters per Member State are analyzed and presented in the report. Moreover, the analysis of the survey data shows which share of driving patterns are compatible with the use of electric cars with their current technical features (batteries range, re-charge time) under alternative assumptions about the availability of re-charge facilities. Also differences and similarities between countries and user groups are discussed. Overall, the results of the survey provide representative driving profiles for estimating the charging profiles of electric vehicles and many other indications on how people use their car. The outcomes of the survey provide relevant methodological hints to develop similar surveys in other contexts or to repeat the survey in other countries.JRC.F.6-Energy systems evaluatio

Effect of Caffeine and Other Methylxanthines on Aβ-Homeostasis in SH-SY5Y Cells

Methylxanthines (MTX) are alkaloids derived from the purine-base xanthine. Whereas especially caffeine, the most prominent known MTX, has been formerly assessed to be detrimental, this point of view has changed substantially. MTXs are discussed to have beneficial properties in neurodegenerative diseases, however, the mechanisms of action are not completely understood. Here we investigate the effect of the naturally occurring caffeine, theobromine and theophylline and the synthetic propentofylline and pentoxifylline on processes involved in Alzheimer’s disease (AD). All MTXs decreased amyloid-β (Aβ) level by shifting the amyloid precursor protein (APP) processing from the Aβ-producing amyloidogenic to the non-amyloidogenic pathway. The α-secretase activity was elevated whereas β-secretase activity was decreased. Breaking down the molecular mechanism, caffeine increased protein stability of the major α-secretase ADAM10, downregulated BACE1 expression and directly decreased β-secretase activity. Additionally, APP expression was reduced. In line with literature, MTXs reduced oxidative stress, decreased cholesterol and a decreased in Aβ1-42 aggregation. In conclusion, all MTXs act via the pleiotropic mechanism resulting in decreased Aβ and show beneficial properties with respect to AD in neuroblastoma cells. However, the observed effect strength was moderate, suggesting that MTXs should be integrated in a healthy diet rather than be used exclusively to treat or prevent AD