Characterization of Heparin-induced Glyceraldehyde-3-phosphate Dehydrogenase Early Amyloid-like Oligomers and Their Implication in alpha-Synuclein Aggregation

Lewy bodies and Lewy neurites, neuropathological hallmarks of several neurological diseases, are mainly made of filamentous assemblies of alpha-synuclein. However, other macromolecules including Tau, ubiquitin, glyceraldehyde-3-phosphate dehydrogenase, and glycosaminoglycans are routinely found associated with these amyloid deposits. Glyceraldehyde-3-phosphate dehydrogenase is a glycolytic enzyme that can form fibrillar aggregates in the presence of acidic membranes, but its role in Parkinson disease is still unknown. In this work, the ability of heparin to trigger the amyloid aggregation of this protein at physiological conditions of pH and temperature is demonstrated by infrared and fluorescence spectroscopy, dynamic light scattering, small angle x-ray scattering, circular dichroism, and fluorescence microscopy. Aggregation proceeds through the formation of short rod-like oligomers, which elongates in one dimension. Heparan sulfate was also capable of inducing glyceraldehyde-3-phosphate dehydrogenase aggregation, but chondroitin sulfates A, B, and C together with dextran sulfate had a negligible effect. Aided with molecular docking simulations, a putative binding site on the protein is proposed providing a rational explanation for the structural specificity of heparin and heparan sulfate. Finally, it is demonstrated that in vitro the early oligomers present in the glyceraldehyde-3-phosphate dehydrogenase fibrillation pathway promote alpha-synuclein aggregation. Taking into account the toxicity of alpha-synuclein prefibrillar species, the heparin-induced glyceraldehyde-3-phosphate dehydrogenase early oligomers might come in useful as a novel therapeutic strategy in Parkinson disease and other synucleinopathies.

Longitudinal familial analysis of blood pressure involving parametric (co)variance functions

Abstract Background For analyzing longitudinal familial data we adopted a log-linear form to incorporate heterogeneity in genetic variance components over the time, and additionally a serial correlation term in the genetic effects at different levels of ages. Due to the availability of multiple measures on the same individual, we permitted environmental correlations that may change across time. Results Systolic blood pressure from family members from the first and second cohort was used in the current analysis. Measures of subjects receiving hypertension treatment were set as censored values and they were corrected. An initial check of the variance and covariance functions proposed for analyzing longitudinal familial data, using empirical semi-variogram plots, indicated that the observed trait dispersion pattern follows the assumptions adopted. Conclusion The corrections for censored phenotypes based on ordinary linear models may be an appropriate simple model to correct the data, ensuring that the original variability in the data was retained. In addition, empirical semi-variogram plots are useful for diagnosis of the (co)variance model adopted.

1031-1034delTAAC (Leu125Stop): a novel familial UBE3A mutation causing Angelman syndrome in two siblings showing distinct phenotypes

Background More than 50 mutations in the UBE3A gene (E6-AP ubiquitin protein ligase gene) have been found in Angelman syndrome patients with no deletion, no uniparental disomy, and no imprinting defect. Case Presentation We here describe a novel UBE3A frameshift mutation in two siblings who have inherited it from their asymptomatic mother. Despite carrying the same UBE3A mutation, the proband shows a more severe phenotype whereas his sister shows a milder phenotype presenting the typical AS features. Conclusions We hypothesized that the mutation Leu125Stop causes both severe and milder phenotypes. Potential mechanisms include: i) maybe the proband has an additional problem (genetic or environmental) besides the UBE3A mutation; ii) since the two siblings have different fathers, the UBE3A mutation is interacting with a different genetic variant in the proband that, by itself, does not cause problems but in combination with the UBE3A mutation causes the severe phenotype; iii) this UBE3A mutation alone can cause either typical AS or the severe clinical picture seen in the proband.

Gagueira desenvolvimental persistente familial: perspectivas genéticas

A gagueira é uma desordem da comunicação oral que tem uma característica multidimensional. A predisposição biológica no desenvolvimento da gagueira ainda não é bem compreendida, mas contribuições genéticas para esta predisposição são reforçadas tanto por referências à agregação familial da gagueira, quanto à gagueira familial, que têm aparecido na literatura há mais de 70 anos. Assim, procuramos estabelecer uma revisão quanto aos prováveis fatores genéticos envolvidos com a manifestação da gagueira desenvolvimental persistente familial. A identificação de genes relacionados à gagueira, bem como de alterações em suas estruturas (por exemplo, mutações), contribuem significativamente para sua compreensão. O modelo exato de transmissão da herança genética para a gagueira ainda não está claramente definida e, provavelmente pode ser diferente entre diferentes famílias e populações. As análises genômicas demonstram, concomitantemente, a relevância dos componentes genéticos envolvidos e sua complexidade, sugerindo assim tratar-se de uma doença poligênica, na qual diversos genes de efeitos variados podem estar envolvidos com o aumento da susceptibilidade de ocorrência da gagueira. O clínico deverá estar alerta ao fato de que uma criança com histórico familial positivo para gagueira poderá ter uma forte tendência a desenvolver o distúrbio de forma crônica. É importante que o clínico esteja atento, de modo a fornecer às famílias orientações precisas sobre o distúrbio. As avaliações objetivas e os tratamentos controlados têm um papel muito importante para o domínio da evolução do distúrbio.

Proctocolectomy and ileal J-pouch anal anastomosis on the surgical treatment of familial adenomatous polyposis and ulcerative colitis: analysis of 49 cases

OBJECTIVE: To evaluate the results of ileal J-pouch anal anastomosis in ulcerative colitis and familial adenomatous polyposis. METHOD: Retrospective analysis of medical records of 49 patients submitted to ileal J-pouch anal anastomosis. RESULTS: Ulcerative colitis was diagnosed in 65% and familial adenomatous polyposis in 34%. Mean age was 39.5 years. 43% were male. Among familial adenomatous polyposis, 61% were diagnosed with colorectal cancer. Thirty-one percent of patients with ulcerative colitis was submitted to a previous surgical approach and 21% of these had toxic megacolon. Average hospital stay was 10 days. Post-operative complications occurred in 50% of patients with ulcerative colitis and 29.4% with familial adenomatous polyposis. Intestinal diversion was performed in 100% of ulcerative colitis and 88% of familial adenomatous polyposis. Pouchitis occurred in eight cases (seven ulcerative colitis and one FAP), requiring excision of the pouch in three ulcerative colitis. Mortality rate was 7.6%: two cases of carcinoma on the pouch and two post-operative complications. Late post-operative complications occurred in 22.4%: six familial adenomatous polyposis and five ulcerative colitis). Two patients had erectile dysfunction, and one retrograde ejaculation. One patient with severe perineal dermatitis was submitted to excision of the pouch. Incontinence occurred in four patients and two reported soil. Mean bowel movement was five times a day. CONCLUSION: Ileal J-pouch anal anastomosis is a safe surgery with acceptable morbidity and good functional results, if well indicated and performed in referral centers.

Inhibition of human platelet aggregation by eosinophils

AIMS: The relationship between the activity of eosinophils and platelets has been observed in recent decades by many scientists. These observations include increased numbers of eosinophils associated with platelet disorders, including changes in the coagulation cascade and platelet aggregation. Based on these observations, the interaction between eosinophils and platelets in platelet aggregation was analyze. MAIN METHODS: Human platelets were incubated with eosinophil cytosolic fraction, promyelocytic human HL-60 clone 15 cell lineage, and eosinophil cationic protein (ECP). Platelet rich plasma (PRP) aggregation was induced by adenosine diphosphate, platelet activating factor, arachidonic acid, and collagen, and washed platelets (WP) were activated by thrombin. KEY FINDINGS: Aggregation induced by all agonists was dose dependently inhibited by eosinophil cytosolic fraction. This inhibition was only partially reversed by previous incubation of the eosinophils with l-Nitro-Arginine-Methyl-Ester (l-NAME). Previous incubation with indomethacin did not prevent the cytosolic fraction induced inhibition. The separation of eosinophil cytosolic fraction by gel filtration on Sephadex G-75 showed that the inhibitory activity was concentrated in the lower molecular weight fraction. HL-60 clone 15 cells differentiated into eosinophils for 5 and 7 day were able to inhibit platelet aggregation. The ECP protein inhibited the platelet aggregation on PRP and WP. This inhibition was more evident in WP, and the citotoxicity MTT assay proved the viability of tested platelets, showing that the observed inhibition by the ECP protein does not occur simply by cell death. SIGNIFICANCE: Our results indicate that eosinophils play a fundamental role in platelet aggregation inhibition

Untersuchungen zur Beteiligung der Preseniline an den molekularen Mechanismen der Amyloid-ß Entstehung

ZusammenfassungMorbus Alzheimer ist eine progressive, neurodegenerative Erkrankung, die weltweit die häufigste Form der Demenz darstellt und im mittleren bis späten Lebensabschnitt auftritt. Die neuropathologischen Merkmale beinhalten das Auftreten von extrazellulären Ablagerungen aus fibrillogenem Aß42 Peptiden in senilen Plaques und intraneuronalen Akkumulationen von hyperphosphoryliertem Tau in sogenannten neurofibrillären Bündeln. Obwohl die meisten Alzheimer Fälle sporadisch und Alters-assoziiert auftreten, gibt es eine autosomal dominant vererbte Form (FAD; Familial Alzheimer Disease), die schon in einem frühen Lebensabschnitt (ab 28 Jahren) ausbrechen kann. Diese aggressive Alzheimer Form wird durch Mutationen im Amyloid-Precursor-Protein-Gen (APP) oder den Presenilin-Genen (PS-1 und PS-2) ausgelöst. Die Presenilin (PS) Proteine sind entscheidend an der Entstehung von Aß beteiligt. So erhöhen FAD-assoziierte Mutationen in PS-1 und PS-2 die Bildung von Aß42. Außerdem verhindern sowohl homozygote PS-1 Null-Mutationen (PS-1-/-) in transgenen Mäusen, als auch dominant negative PS-1 Mutationen in Kulturzellen die Ab Bildung. Diese Belege sprechen für die zur Zeit favorisierte Amyloid Hypothese, in der die toxische Wirkung des Aß-Peptides in der Entstehung der Alzheimer Erkrankung eine zentrale Rolle einnimmt. Die y-Sekretase ist eine Protease, deren Aktivität für die Entstehung von Ab aus dem Vorläuferprotein APP essentiell ist. Damit bildet sie einen möglichen Ansatzpunkt, um grundlegend in den Prozeß der Ab Bildung einzugreifen. Die y-Sekretase ist allerdings noch nicht identifiziert oder kloniert. Es gibt Hinweise, daß die Preseniline y-Sekretase Aktivität besitzen könnten. Diese Theorie ist bis heute jedoch nicht eindeutig belegt. In dieser Arbeit sollten die molekularen Mechanismen der Ab Entstehung und insbesondere die Beteiligung der Preseniline an diesem Prozeß untersucht werden. Dazu wurde zunächst die subzelluläre Verteilung der endogenen Preseniline analysiert. Es konnte erstmalig ein Unterschied in der subzellulären Verteilung zwischen PS-1 und PS-2 festgestellt werden. PS-1 war vorwiegend im ER lokalisiert, wogegen PS-2 stark im Golgi-Apparat angereichert war. Im zweiten Teil der Arbeit wurde nach möglichen Interaktionen der Preseniline mit C-terminalen APP Fragmenten gesucht, die die Substrate der y-Sekretase darstellen. Es konnte gezeigt werden, daß die Preseniline mit einem 21 kDa großen C-terminalen APP Fragment interagieren. Dabei band die Mutante-Form der Preseniline mehr C-terminales APP Fragment als die Wildtyp-Form. Weiterhin wurde ein zellfreies System zur indirekten Bestimmung der y-Sekretase Aktivität etabliert. Mit Hilfe dieses Systems wird es möglich, Inhibitoren der y-Sekretase zu identifizieren. Die Spezifität des zellfreien Testsystems konnte dadurch deutlich gemacht werden, daß das PS-1, das schon in Zellkultur als essentielle Proteinkomponente zur Entstehung von Aß beschrieben wurde, auch in diesem zellfreien y-Sekretase System notwendig war. Allgemeine Proteaseinhibitoren, die alle bekannten Proteasemechanismen abdeckten, zeigten keinen Einfluß auf die de novo Bildung von Aß. Es konnte festgestellt werden, daß neben der y-Sekretase als Aß produzierende Protease auch Aß abbauende Proteasen vorlagen. Das pH-Optimum der y-Sekretase wurde im neutralen Bereich festgestellt. Weiterhin konnte gezeigt werden, daß die y-Sekretase eine transmembrane oder zumindest membranassoziierte Protease ist, die keine cytosolischen Komponenten benötigt.

Impact of ocean acidification on phytoplankton growth and aggregation

Since the industrial revolution, the ocean has absorbed around one third of the anthropogenic CO2, which induced a profound alteration of the carbonate system commonly known as ocean acidification. Since the preindustrial times, the average ocean surface water pH has fallen by 0.1 units, from approximately 8.2 to 8.1 and a further decrease of 0.4 pH units is expected for the end of the century. Despite their microscopic size, marine diatoms are bio-geo-chemically a very important group, responsible for the export of massive amount of carbon to deep waters and sediments. The knowledge of the potential effects of ocean acidification on the phytoplankton growth and on biological pump is still at its infancy. This study wants to investigate the effect of ocean acidification on the growth of the diatom Skeletonema marinoi and on its aggregation, using a mechanistic approach. The experiment consisted of two treatments (Present and Future) representing different pCO2 conditions and two sequential experimental phases. During the cell growth phase a culture of S. marinoi was inoculated into transparent bags and the effect of ocean acidification was studied on various growth parameters, including DOC and TEP production. The aggregation phase consisted in the incubation of the cultures into rolling tanks where the sinking of particles through the water column was simulated and aggregation promoted. Since few studies investigated the effect of pH on the growth of S. marinoi and none used pH ranges that are compatible with the OA scenarios, there were no baselines. I have shown here, that OA does not affect the cell growth of S. marinoi, suggesting that the physiology of this species is robust in respect to the changes in the carbonate chemistry expected for the end of the century. Furthermore, according to my results, OA does not affect the aggregation of S. marinoi in a consistent manner, suggesting that this process has a high natural variability but is not influenced by OA in a predictable way. The effect of OA was tested over a variety of factors including the number of aggregates produced, their size and sinking velocity, the algal, bacterial and TEP content. Many of these variables showed significant treatment effects but none of these were consistent between the two experiments.

Gamma-secretase modulators and inhibitors in Alzheimer's disease: influence of genetic background on efficacy and mechanism of action

According to the amyloid hypothesis, Alzheimer’s disease (AD) is caused by aberrant production or clearance of the amyloid-β (Aβ) peptides, and in particular of the longer more aggregation-prone Aβ42. The Aβ peptides are generated through successive proteolytic cleavage of the amyloid precursor protein (APP) by the β-site APP cleaving enzyme (BACE) and γ-secretase. γ-secretase produces Aβ peptides with variable C-termini ranging from Aβ34 to Aβ48, presumably by sequential trimming of longer into shorter peptides. γ-secretase is a multiprotein complex consisting of at least four different proteins and the presenilin proteins (PS1 or PS2) contain the catalytic center of the complex. In 2001 several non-steroidal anti-inflammatory drugs were identified as the founding members of a new class of γ-secretase modulators (GSMs) that can selectively reduce production of Aβ42. Concomitantly, these GSMs increase Aβ38 production indicating closely coordinated generation of Aβ42 and Aβ38 and a potential precursor-product relationship between these peptides. GSMs seem to exert their activity by direct modulation of γ-secretase. Support for this hypothesis is drawn from the finding that some PS mutations associated with early-onset familial AD (FAD) can modulate the cellular response to GSMs and to γ-secretase inhibitors (GSIs), which inhibit production of all Aβ peptides and are known to directly interact with PS. A particularly interesting FAD PS mutation is PS1-ΔExon9, a complex deletion mutant that blocks endoproteolysis of PS1 and renders cells completely non-responsive to GSMs. Studies presented in this thesis show that the diminished response of PS1-ΔExon9 to GSMs is mainly caused by its lack of endoproteolytic cleavage. Furthermore, we were able to demonstrate that a reduced response to GSMs and GSIs is not limited to PS1-ΔExon9 but is a common effect of aggressive FAD-associated PS1 mutations. Surprisingly, we also found that while the Aβ42 response to GSMs is almost completely abolished by these PS1 mutations, the accompanying Aβ38 increase was indistinguishable to wild-type PS1. Finally, the reduced response to GSIs was confirmed in a mouse model with transgenic expression of an aggressive FAD-associated PS1 mutation as a highly potent GSI failed to reduce Aβ42 levels in brain of these mice. Taken together, our findings provide clear evidence for independent generation of Aβ42 and Aβ38 peptides, and argue that the sequential cleavage model might be an oversimplification of the molecular mechanism of γ-secretase. Most importantly, our results highlight the significance of genetic background in drug discovery efforts aimed at γ-secretase, and indicate that the use of cellular models with transgenic expression of FAD-associated PS mutations might confound studies of the potency and efficacy of GSMs and GSIs. Therefore, such models should be strictly avoided in the ongoing preclinical development of these promising and potentially disease-modifying therapeutics for AD.

The KIT gene in familial mastocytosis

Familial cutaneous mastocytosis is an exceptional condition of unknown etiology. In this study we report the largest series of patients with familial cutaneous mastocytosis without other manifestations (18 affected subjects from seven unrelated families), and we investigate the role of germ-line KIT mutations in the pathogenesis of the disease. The mean age at onset was 5.4 years (range from birth to 22 years), and the clinical behavior was variable over a mean follow up period of 15.1 years (range 2-36): improvement in seven, stability in eight and worsening in the remaining three patients. The pattern of inheritance was compatible with an autosomal dominant trait with incomplete penetrance; a female preponderance (14 females vs 4 males, ratio 3.5:1) was noted; among the six women who have been pregnant at least once, three experienced important clinical changes during pregnancy. No germ-line mutation was found in the exons 10, 11, and 17 of the KIT proto-oncogene, which are the most commonly mutated exons in sporadic mastocytosis. However, in the majority of affected subjects we found the Met541Leu polymorphic variant of the KIT gene, which seems to confer a growth advantage to mast cells in vitro. This observation further suggests that the Met541Leu may be a predisposing factor of cutaneous mastocytosis, although it seems to be neither necessary nor sufficient for the development of the disease.

Development and applications of hollow fiber flow field-flow fractionation in the bioanalytical field. Studies of aggregation phenomena in complex protein samples

Recent advances in the fast growing area of therapeutic/diagnostic proteins and antibodies - novel and highly specific drugs - as well as the progress in the field of functional proteomics regarding the correlation between the aggregation of damaged proteins and (immuno) senescence or aging-related pathologies, underline the need for adequate analytical methods for the detection, separation, characterization and quantification of protein aggregates, regardless of the their origin or formation mechanism. Hollow fiber flow field-flow fractionation (HF5), the miniaturized version of FlowFFF and integral part of the Eclipse DUALTEC FFF separation system, was the focus of this research; this flow-based separation technique proved to be uniquely suited for the hydrodynamic size-based separation of proteins and protein aggregates in a very broad size and molecular weight (MW) range, often present at trace levels. HF5 has shown to be (a) highly selective in terms of protein diffusion coefficients, (b) versatile in terms of bio-compatible carrier solution choice, (c) able to preserve the biophysical properties/molecular conformation of the proteins/protein aggregates and (d) able to discriminate between different types of protein aggregates. Thanks to the miniaturization advantages and the online coupling with highly sensitive detection techniques (UV/Vis, intrinsic fluorescence and multi-angle light scattering), HF5 had very low detection/quantification limits for protein aggregates. Compared to size-exclusion chromatography (SEC), HF5 demonstrated superior selectivity and potential as orthogonal analytical method in the extended characterization assays, often required by therapeutic protein formulations. In addition, the developed HF5 methods have proven to be rapid, highly selective, sensitive and repeatable. HF5 was ideally suitable as first dimension of separation of aging-related protein aggregates from whole cell lysates (proteome pre-fractionation method) and, by HF5-(UV)-MALS online coupling, important biophysical information on the fractionated proteins and protein aggregates was gathered: size (rms radius and hydrodynamic radius), absolute MW and conformation.

Aggregation of hybrid molecules and film formation of colloidal monolayers

A unique characteristic of soft matter is its ability to self-assemble into larger structures. Characterizing these structures is crucial for their applications. In the first part of this work, I investigated DNA-organic hybrid material by means of Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Cross-Correlation Spectroscopy (FCCS). DNA-organic hybrid materials, a novel class of hybrid materials composed of synthetic macromolecules and oligodeoxynucleotide segmenta, are mostly amphiphilic and can self-assemble into supramolecular structures in aqueous solution. A hybrid material of a fluorophore, perylenediimide (PDI), and a DNA segment (DNA-PDI) has been developed in Prof. A. Hermann’s group (University of Groningen). This novel material has the ability to form aggregates through pi-pi stacking between planar PDIs and can be traced in solution due to the fluorescence of PDI. I have determined the diffusion coefficient of DNA-PDI conjugates in aqueous solution by means of FCS. In addition, I investigated whether such DNA-PDIs form aggregates with certain structure, for instance dimers. rnOnce the DNA hybrid material self-assemble into supermolecular structures for instance into micelles, the single molecules do not necessarily stay in one specific micelle. Actually, a single molecule may enter and leave micelles constantly. The average residence time of a single molecule in a certain micelle depends on the nature of the molecule. I have chosen DNA-b-polypropylene oxide (PPO) as model molecules and investigated the residence time of DNA-b-PPO molecules in their according micelles by means of FCCS.rnBesides the DNA hybrid materials, polymeric colloids can also form ordered structures once they are brought to an air/water interface. Here, hexagonally densely packed monolayers can be generated. These monolayers can be deposited onto different surfaces as coating layers. In the second part of this work, I investigated the mechanical properties of such colloidal monolayers using micromechanical cantilevers. When a coating layer is deposited on a cantilever, it can modify the elasticity of the cantilever. This variation can be reflected either by a deflection or by a resonance frequency shift of the cantilever. In turn, detecting these changes provides information about the mechanical properties of the coating layer. rnIn the second part of this work, polymeric colloidal monolayers were coated on a cantilever and homogenous polymer films of a few hundred nanometers in thickness were generated from these colloidal monolayers by thermal annealing or organic vapor annealing. Both the film formation process and the mechanical properties of these resulting homogenous films were investigated by means of cantilever. rnElastic property changes of the coating film, for example upon absorption of organic vapors, induce a deflection of the cantilever. This effect enables a cantilever to detect target molecules, when the cantilever is coated with an active layer with specific affinity to target molecules. In the last part of this thesis, I investigated the applicability of suitably functionalized micromechanical cantilevers as sensors. In particular, glucose sensitive polymer brushes were grafted on a cantilever and the deflection of this cantilever was measured during exposure to glucose solution. rn

Regulation des Proteins Alpha-Synuclein während der zellulären Alterung

α-Synuclein wird durch Mutationen sowie der Ausbildung von Proteinaggregaten namens Lewy-Körperchen mit der Entstehung der altersassoziierten Parkinson-Krankheit in Verbindung gebracht. Sowohl familiäre als auch sporadische Fälle sind durch erhöhte α-Synuclein-Spiegel gekennzeichnet. In familiären Fällen wurden Multiplikationen des α-Synuclein-Gens als Ursache für die erhöhte Expression aufgedeckt. In sporadischen Fällen stellt die Alterung den entscheidenden Risikofaktor für die Entstehung der Krankheit dar. Daher wurde in der vorliegenden Arbeit die Regulation von α-Synuclein während der zellulären Alterung in humanen Fibroblasten untersucht. In seneszenten Zellen konnte ein Anstieg der α-Synuclein-Expression nachgewiesen werden, der jedoch die Löslichkeit des Proteins nicht veränderte. Damit scheint die zelluläre Alterung per se nicht für die Aggregation des Proteins, wie sie in Form von Lewy-Körperchen bei z. B. Patienten der Parkinson-Krankheit beobachtet wird, verantwortlich zu sein. Möglicherweise ist die Hochregulation von α-Synuclein eine Folge der Akkumulation von DNA-Schäden in den seneszenten Zellen. Diese Korrelation konnte in jungen Zellen nach dem Einsatz verschiedener DNA-schädigender Agenzien bestätigt werden. Die Untersuchung des Regulationsmechanismus ergab, dass die erhöhte Expression von α-Synuclein in Folge von DNA-Schäden über den ERK1/2-MAPK-Signalweg vermittelt wird. In seneszenten Zellen konnte ebenfalls ein Einfluss dieses Signalweges auf die Expression von α-Synuclein beobachtet werden, allerdings scheint dieser nicht alleinig für die Hochregulation verantwortlich zu sein. Des Weiteren ergab die Betrachtung des γH2A.X-Spiegels nach Induktion von DNA-Schäden, dass α-Synuclein möglicherweise eine protektive Funktion besitzt, da dessen Überexpression zu einer verringerten und die Herunterregulation zu einer vermehrten DNA-Schädigung führte. Die Analyse der subzellulären Lokalisation von α-Synuclein ergab außerdem, dass es in jungen Zellen nach der Induktion von DNA-Schäden zu einer Translokation des Proteins in den Zellkern kommt. Diese Translokation war in seneszenten Zellen verringert. Dies lässt vermuten, dass α-Synuclein in jungen Zellen nach DNA-Schädigung durch den ERK1/2-MAPK-Signalweg hochreguliert wird und durch die Translokation in den Zellkern möglicherweise die Transkription von protektiven Genen beeinflusst oder an DNA-Reparatur-Prozessen beteiligt ist. In seneszenten Zellen ist das Protein zwar deutlich stärker exprimiert, der Transport in den Zellkern jedoch verringert, wodurch die protektive Wirkung im Zellkern herabgesetzt wäre.

A randomised determination of the effect of fluvastatin and atorvastatin on top of dual antiplatelet treatment on platelet aggregation after implantation of coronary drug-eluting stents. The EFA-Trial

Drug-drug interaction between statins metabolised by cytochrome P450 3A4 and clopidogrel have been claimed to attenuate the inhibitory effect of clopidogrel. However, published data regarding this drug-drug interaction are controversial. We aimed to determine the effect of fluvastatin and atorvastatin on the inhibitory effect of dual antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel. One hundred one patients with symptomatic stable coronary artery disease undergoing percutaneous coronary intervention and drug-eluting stent implantation were enrolled in this prospective randomised study. After an interval of two weeks under dual antiplatelet therapy with ASA and clopidogrel, without any lipid-lowering drug, 87 patients were randomised to receive a treatment with either fluvastatin 80 mg daily or atorvastatin 40 mg daily in addition to the dual antiplatelet therapy for one month. Platelet aggregation was assessed using light transmission aggregometry and whole blood impedance platelet aggregometry prior to randomisation and after one month of receiving assigned statin and dual antiplatelet treatment. Platelet function assessment after one month of statin and dual antiplatelet therapy did not show a significant change in platelet aggregation from 1st to 2nd assessment for either statin group. There was also no difference between atorvastatin and fluvastatin treatment arms. In conclusion, neither atorvastatin 40 mg daily nor fluvastatin 80 mg daily administered in combination with standard dual antiplatelet therapy following coronary drug-eluting stent implantation significantly interfere with the antiaggregatory effect of ASA and clopidogrel.