@phdthesis{Rothe2013, author = {Rothe, Monique}, title = {Response of intestinal Escherichia coli to dietary factors in the mouse intestine}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66387}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Diet is a major force influencing the intestinal microbiota. This is obvious from drastic changes in microbiota composition after a dietary alteration. Due to the complexity of the commensal microbiota and the high inter-individual variability, little is known about the bacterial response at the cellular level. The objective of this work was to identify mechanisms that enable gut bacteria to adapt to dietary factors. For this purpose, germ-free mice monoassociated with the commensal Escherichia coli K-12 strain MG1655 were fed three different diets over three weeks: a diet rich in starch, a diet rich in non-digestible lactose and a diet rich in casein. Two dimensional gel electrophoresis and electrospray tandem mass spectrometry were applied to identify differentially expressed proteins of E. coli recovered from small intestine and caecum of mice fed the lactose or casein diets in comparison with those of mice fed the starch diet. Selected differentially expressed bacterial proteins were characterised in vitro for their possible roles in bacterial adaptation to the various diets. Proteins belonging to the oxidative stress regulon oxyR such as alkyl hydroperoxide reductase subunit F (AhpF), DNA protection during starvation protein (Dps) and ferric uptake regulatory protein (Fur), which are required for E. coli's oxidative stress response, were upregulated in E. coli of mice fed the lactose-rich diet. Reporter gene analysis revealed that not only oxidative stress but also carbohydrate-induced osmotic stress led to the OxyR-dependent expression of ahpCF and dps. Moreover, the growth of E. coli mutants lacking the ahpCF or oxyR genes was impaired in the presence of non-digestible sucrose. This indicates that some OxyR-dependent proteins are crucial for the adaptation of E. coli to osmotic stress conditions. In addition, the function of two so far poorly characterised E. coli proteins was analysed: 2 deoxy-D gluconate 3 dehydrogenase (KduD) was upregulated in intestinal E. coli of mice fed the lactose-rich diet and this enzyme and 5 keto 4 deoxyuronate isomerase (KduI) were downregulated on the casein-rich diet. Reporter gene analysis identified galacturonate and glucuronate as inducers of the kduD and kduI gene expression. Moreover, KduI was shown to facilitate the breakdown of these hexuronates, which are normally degraded by uronate isomerase (UxaC), altronate oxidoreductase (UxaB), altronate dehydratase (UxaA), mannonate oxidoreductase (UxuB) and mannonate dehydratase (UxuA), whose expression was repressed by osmotic stress. The growth of kduID-deficient E. coli on galacturonate or glucuronate was impaired in the presence of osmotic stress, suggesting KduI and KduD to compensate for the function of the regular hexuronate degrading enzymes under such conditions. This indicates a novel function of KduI and KduD in E. coli's hexuronate metabolism. Promotion of the intracellular formation of hexuronates by lactose connects these in vitro observations with the induction of KduD on the lactose-rich diet. Taken together, this study demonstrates the crucial influence of osmotic stress on the gene expression of E. coli enzymes involved in stress response and metabolic processes. Therefore, the adaptation to diet-induced osmotic stress is a possible key factor for bacterial colonisation of the intestinal environment.}, language = {en} } @phdthesis{Toele2013, author = {T{\"o}le, Jonas Claudius}, title = {{\"U}ber die Arc-catFISH-Methode als neues Werkzeug zur Charakterisierung der Geschmacksverarbeitung im Hirnstamm der Maus}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70491}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Intensive Forschung hat in den vergangenen Jahrzehnten zu einer sehr detaillierten Charakterisierung des Geschmackssystems der S{\"a}ugetiere gef{\"u}hrt. Dennoch sind mit den bislang eingesetzten Methoden wichtige Fragestellungen unbeantwortet geblieben. Eine dieser Fragen gilt der Unterscheidung von Bitterstoffen. Die Zahl der Substanzen, die f{\"u}r den Menschen bitter schmecken und in Tieren angeborenes Aversionsverhalten ausl{\"o}sen, geht in die Tausende. Diese Substanzen sind sowohl von der chemischen Struktur als auch von ihrer Wirkung auf den Organismus sehr verschieden. W{\"a}hrend viele Bitterstoffe potente Gifte darstellen, sind andere in den Mengen, die mit der Nahrung aufgenommen werden, harmlos oder haben sogar positive Effekte auf den K{\"o}rper. Zwischen diesen Gruppen unterscheiden zu k{\"o}nnen, w{\"a}re f{\"u}r ein Tier von Vorteil. Ein solcher Mechanismus ist jedoch bei S{\"a}ugetieren nicht bekannt. Das Ziel dieser Arbeit war die Untersuchung der Verarbeitung von Geschmacksinformation in der ersten Station der Geschmacksbahn im Mausgehirn, dem Nucleus tractus solitarii (NTS), mit besonderem Augenmerk auf der Frage nach der Diskriminierung verschiedener Bitterstoffe. Zu diesem Zweck wurde eine neue Untersuchungsmethode f{\"u}r das Geschmackssystem etabliert, die die Nachteile bereits verf{\"u}gbarer Methoden umgeht und ihre Vorteile kombiniert. Die Arc-catFISH-Methode (cellular compartment analysis of temporal activity by fluorescent in situ hybridization), die die Charakterisierung der Antwort großer Neuronengruppen auf zwei Stimuli erlaubt, wurde zur Untersuchung geschmacksverarbeitender Zellen im NTS angewandt. Im Zuge dieses Projekts wurde erstmals eine stimulusinduzierte Arc-Expression im NTS gezeigt. Die ersten Ergebnisse offenbarten, dass die Arc-Expression im NTS spezifisch nach Stimulation mit Bitterstoffen auftritt und sich die Arc exprimierenden Neurone vornehmlich im gustatorischen Teil des NTS befinden. Dies weist darauf hin, dass Arc-Expression ein Marker f{\"u}r bitterverarbeitende gustatorische Neurone im NTS ist. Nach zweimaliger Stimulation mit Bittersubstanzen konnten {\"u}berlappende, aber verschiedene Populationen von Neuronen beobachtet werden, die unterschiedlich auf die drei verwendeten Bittersubstanzen Cycloheximid, Chininhydrochlorid und Cucurbitacin I reagierten. Diese Neurone sind vermutlich an der Steuerung von Abwehrreflexen beteiligt und k{\"o}nnten so die Grundlage f{\"u}r divergentes Verhalten gegen{\"u}ber verschiedenen Bitterstoffen bilden.}, language = {de} } @phdthesis{MostafaKamelAbdelfatah2013, author = {Mostafa Kamel Abdelfatah, Ali}, title = {Interactions of food proteins with plant phenolics - modulation of structural, techno- and bio-functional properties of proteins}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69033}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {The phenolic compounds as food components represent the largest group of secondary metabolites in plant foods. The phenolic compounds, e.g. chlorogenic acid (CQA), are susceptible to oxidation by enzymes specially, polyphenol oxidase (PPO) and at alkaline conditions. Both enzymatic and non-enzymatic oxidations occur in the presence of oxygen and produce quinone, which normally further react with other quinone to produce colored compounds (dimers), as well as is capable of undergoing a nucleophilic addition to proteins. The interactions of proteins with the phenolic compounds have received considerable attention in the recent years where, plant phenolic compounds have drawn increasing attention due to their antioxidant properties and their noticeable effects in the prevention of various oxidative stress associated diseases. Green coffee beans are one of the richest sources of chlorogenic acids. Therefore, a green coffee extract would provide an eligible food relevant source for phenolic compounds for modification of proteins. The interaction between 5-CQA and amino acid lysine showed decrease in both free CQA and amino acid groups and only a slight effect on the antioxidative capacity depending on the reaction time was found. Furthermore, this interaction showed a large number of intermediary substances of low intensities. The reaction of lysine with 5-CQA in a model system initially leads to formation of 3-CQA and 4-CQA (both are isomers of 5-CQA), oxidation giving rise to the formation of a dimer which subsequently forms an adduct with lysine to finally result in a benzacridine derivative as reported and confirmed with the aid of HPLC coupled with ESI-MSn. The benzacridine derivative containing a trihydroxy structural element, was found to be yellow, being very reactive with oxygen yielding semiquinone and quinone type of products with characteristic green colors. Finally, the optimal conditions for this interaction as assessed by both the loss of CQA and free amino groups of lysine can be given at pH 7 and 25°C, the interaction increasing with incubation time and depending also on the amount of tyrosinase present. Green coffee bean has a higher diversity and content of phenolics, where besides the CQA isomers and their esters, other conjugates like feruloylquinic acids were also identified, thus documenting differences in phenolic profiles for the two coffee types (Coffea arabica and Coffea robusta). Coffee proteins are modified by interactions with phenolic compounds during the extraction, where those from C. arabica are more susceptible to these interactions compared to C. robusta, and the polyphenol oxidase activity seems to be a crucial factor for the formation of these addition products. Moreover, In-gel digestion combined with MALDI-TOF-MS revealed that the most reactive and susceptible protein fractions to covalent reactions are the α-chains of the 11S storage protein. Thus, based on these results and those supplied by other research groups, a tentative list of possible adduct structures was derived. The diversity of the different CQA derivatives present in green coffee beans complicates the series of reactions occurring, providing a broad palette of reaction products. These interactions influence the properties of protein, where they exposed changes in the solubility and hydrophobicity of proteins compared to faba bean proteins (as control). Modification of milk whey protein products (primarily b-lactoglobulin) with coffee specific phenolics and commercial CQA under enzymatic and alkaline conditions seems to be affecting their chemical, structural and functional properties, where both modifications led to reduced free amino-,thiol groups and tryptophan content. We propose that the disulfide-thiol exchange in the C-terminus of b-lactoglobulin may be initiated by the redox conditions provided in the presence of CQA. The protein structure b-lactoglobulin thereupon becomes more disordered as simulated by molecular dynamic calculation. This unfolding process may additionally be supported by the reaction of the CQA at the proposed sites of modification of -amino groups of lysine (K77, K91, K138, K47) and the thiol group of cysteine (C121). These covalent modifications also decreased the solubility and hydrophobicity of b-lactoglobulin, moreover they provide modified protein samples with a high antioxidative power, thermally more stable as reflected by a higher Td, require less amount of energy to unfold and when emulsified with lutein esters, exhibit their higher stability against UV light. The MALDI-TOF and SDS-PAGE results revealed that proteins treated at alkaline conditions were more strongly modified than those treated under enzymatic conditions. Finally, the results showed a slight change in emulsifying properties of modified proteins.}, language = {en} } @phdthesis{Ganesh2013, author = {Ganesh, Bhanu Priya}, title = {Host-microbe interactions in the inflamed gut}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69558}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Initiation and perpetuation of inflammatory bowel diseases (IBD) may result from an exaggerated mucosal immune response to the luminal microbiota in a susceptible host. We proposed that this may be caused either 1) by an abnormal microbial composition or 2) by weakening of the protective mucus layer due to excessive mucus degradation, which may lead to an easy access of luminal antigens to the host mucosa triggering inflammation. We tested whether the probiotic Enterococcus faecium NCIMB 10415 (NCIMB) is capable of reducing chronic gut inflammation by changing the existing gut microbiota composition and aimed to identify mechanisms that are involved in possible beneficial effects of the probiotic. To identify health-promoting mechanisms of the strain, we used interleukin (IL)-10 deficient mice that spontaneously develop gut inflammation and fed these mice a diet containing NCIMB (106 cells g-1) for 3, 8 and 24 weeks, respectively. Control mice were fed an identically composed diet but without the probiotic strain. No clear-cut differences between the animals were observed in pro-inflammatory cytokine gene expression and in intestinal microbiota composition after probiotic supplementation. However, we observed a low abundance of the mucin-degrading bacterium Akkermansia muciniphila in the mice that were fed NCIMB for 8 weeks. These low cell numbers were associated with significantly lower interferon gamma (IFN-γ) and IFN-γ-inducible protein (IP-10) mRNA levels as compared to the NCIMB-treated mice that were killed after 3 and 24 weeks of intervention. In conclusion, NCIMB was not capable of reducing gut inflammation in the IL-10-/- mouse model. To further identify the exact role of A. muciniphila and uncover a possible interaction between this bacterium, NCIMB and the host in relation to inflammation, we performed in vitro studies using HT-29 colon cancer cells. The HT-29 cells were treated with bacterial conditioned media obtained by growing either A. muciniphila (AM-CM) or NCIMB (NCIMB-CM) or both together (COMB-CM) in Dulbecco's Modified Eagle Medium (DMEM) for 2 h at 37 °C followed by bacterial cell removal. HT-29 cells treated with COMB-CM displayed reduced cell viability after 18 h (p<0.01) and no viable cells were detected after 24 h of treatment, in contrast to the other groups or heated COMB-CM. Detection of activated caspase-3 in COMB-CM treated groups indicated that death of the HT-29 cells was brought about by apoptosis. It was concluded that either NCIMB or A. muciniphila produce a soluble and heat-sensitive factor during their concomitant presence that influences cell viability in an in vitro system. We currently hypothesize that this factor is a protein, which has not yet been identified. Based on the potential effect of A. muciniphila on inflammation (in vivo) and cell-viability (in vitro) in the presence of NCIMB, we investigated how the presence of A. muciniphila affects the severity of an intestinal Salmonella enterica Typhimurium (STm)-induced gut inflammation using gnotobiotic C3H mice with a background microbiota of eight bacterial species (SIHUMI, referred to as simplified human intestinal microbiota). Presence of A. muciniphila in STm-infected SIHUMI (SIHUMI-AS) mice caused significantly increased histopathology scores and elevated mRNA levels of IFN-γ, IP-10, tumor necrosis factor alpha (TNF-α), IL-12, IL-17 and IL-6 in cecal and colonic tissue. The number of mucin filled goblet cells was 2- to 3- fold lower in cecal tissue of SIHUMI-AS mice compared to SIHUMI mice associated with STm (SIHUMI-S) or A. muciniphila (SIHUMI-A) or SIHUMI mice. Reduced goblet cell numbers significantly correlated with increased IFN-γ (r2 = -0.86, ***P<0.001) in all infected mice. In addition, loss of cecal mucin sulphation was observed in SIHUMI-AS mice. Concomitant presence of A. muciniphila and STm resulted in a drastic change in microbiota composition of the SIHUMI consortium. The proportion of Bacteroides thetaiotaomicron in SIHUMI, SIHUMI-A and SIHUMI-S mice made up to 80-90\% but was completely taken over by STm in SIHUMI-AS mice contributing 94\% to total bacteria. These results suggest that A. muciniphila exacerbates STm-induced intestinal inflammation by its ability to disturb host mucus homeostasis. In conclusion, abnormal microbiota composition together with excessive mucus degradation contributes to severe intestinal inflammation in a susceptible host.}, language = {en} } @phdthesis{Thalmann2013, author = {Thalmann, Sophie}, title = {Korrelation zwischen der genetischen und der funktionellen Diversit{\"a}t humaner Bitterrezeptoren}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66845}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Der Mensch besitzt ~25 funktionelle Bitterrezeptoren (TAS2R), die f{\"u}r die Wahrnehmung potenziell toxischer Substanzen in der Nahrung verantwortlich sind. Aufgrund der großen genetischen Variabilit{\"a}t der TAS2R-Gene k{\"o}nnte es eine Vielzahl funktionell unterschiedlicher TAS2R-Haplotypen geben, die zu Unterschieden der Bitterwahrnehmung f{\"u}hren. Dies konnte bereits in funktionellen Analysen und sensorischen Studien f{\"u}r einzelne Bitterrezeptoren gezeigt werden. In dieser Arbeit wurden die h{\"a}ufigsten Haplotypen aller 25 Bitterrezeptoren verschiedener Ethnien funktionell charakterisiert. Das Ziel war eine umfassende Aussage {\"u}ber die funktionelle Diversit{\"a}t der TAS2Rs, die die molekulare Grundlage f{\"u}r individuelle Bitterwahrnehmung bildet, treffen zu k{\"o}nnen. Fehlende Varianten wurden aus genomischer DNA kloniert oder durch gezielte Mutagenese bereits vorhandener TAS2R-Konstrukte generiert. Die funktionelle Analyse erfolgte mittels Expression der TAS2R-Haplotypen in HEK293TG16gust44 Zellen und anschließenden Calcium-Imaging-Experimenten mit zwei bekannten Agonisten. Die Haplotypen der f{\"u}nf orphanen TAS2Rs wurden mit {\"u}ber hundert Bitterstoffen stimuliert. Durch die gelungene Deorphanisierung des TAS2R41 in dieser Arbeit, wurden f{\"u}r die 21 aktivierbaren TAS2Rs 36 funktionell-unterschiedliche Haplotypen identifiziert. Die tats{\"a}chliche funktionelle Vielfalt blieb jedoch deutlich hinter der genetischen Variabilit{\"a}t der TAS2Rs zur{\"u}ck. Neun Bitterrezeptoren wiesen funktionell homogene Haplotypen auf oder besaßen nur eine weltweit vorherrschende Variante. Funktionell heterogene Haplotypen wurden f{\"u}r zw{\"o}lf TAS2Rs identifiziert. Inaktive Varianten der Rezeptoren TAS2R9, TAS2R38 und TAS2R46 sollten die Wahrnehmung von Bitterstoffen wie Ofloxacin, Cnicin, Hydrocortison, Limonin, Parthenolid oder Strychnin beeinflussen. Unterschiedlich sensitive Varianten, besonders der Rezeptoren TAS2R47 und TAS2R49, sollten f{\"u}r Agonisten wie Absinthin, Amarogentin oder Cromolyn ebenfalls zu ph{\"a}notypischen Unterschieden f{\"u}hren. Wie f{\"u}r den TAS2R16 bereits gezeigt, traten Haplotypen des funktionell heterogenen TAS2R7 und TAS2R41 ethnien-spezifisch auf, was auf lokale Anpassung und verschiedene Ph{\"a}notypen hinweisen k{\"o}nnte. Weiterf{\"u}hrend muss nun eine Analyse der funktionell-variablen TAS2Rs in sensorischen Tests erfolgen, um ihre ph{\"a}notypische Relevanz zu pr{\"u}fen. Die Analyse der funktionsmodulierenden Aminos{\"a}urepositionen, z.Bsp. des TAS2R44, TAS2R47 oder TAS2R49, k{\"o}nnte weiterf{\"u}hrend zum besseren Verst{\"a}ndnis der Rezeptor-Ligand- und Rezeptor-G-Protein-Interaktion beitragen.}, language = {de} } @phdthesis{Mueller2013, author = {M{\"u}ller, Mike-Freya}, title = {Die Glutathionperoxidase 2 : physiologische Funktion und Rolle in der Azoxymethan-induzierten Colonkanzerogenese}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66955}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Das Selenoprotein Glutathionperoxidase 2 (GPx2) ist ein epithelzellspezifisches, Hydroperoxide-reduzierendes Enzym, welches im Darmepithel, vor allem in den proliferierenden Zellen des Kryptengrundes, exprimiert wird. Die Aufrechterhaltung der GPx2-Expression im Kryptengrund auch bei subad{\"a}quatem Selenstatus k{\"o}nnte darauf hinweisen, dass sie hier besonders wichtige Funktionen wahrnimmt. Tats{\"a}chlich weisen GPx2 knockout (KO)-M{\"a}use eine erh{\"o}hte Apoptoserate im Kryptengrund auf. Ein Ziel dieser Arbeit war es deshalb, die physiologische Funktion der GPx2 n{\"a}her zu untersuchen. In Kryptengrundepithelzellen aus dem Colon selenarmer GPx2 KO-M{\"a}use wurde eine erh{\"o}hte Caspase 3/7-Aktivit{\"a}t im Vergleich zum Wildtyp (WT) festgestellt. Zudem wiesen diese Zellen eine erh{\"o}hte Suszeptibilit{\"a}t f{\"u}r oxidativen Stress auf. Die GPx2 gew{\"a}hrleistet also den Schutz der proliferierenden Zellen des Kryptengrundes auch bei subad{\"a}quater Selenversorgung. Des Weiteren wurde im Colon selenarmer (-Se) und -ad{\"a}quater (+Se) GPx2 KO-M{\"a}use im Vergleich zum WT eine erh{\"o}hte Tumornekrosefaktor α-Expression und eine erh{\"o}hte Infiltration von Makrophagen festgestellt. Durch F{\"u}tterung einer selensupplementierten Di{\"a}t (++Se) konnte dies verhindert werden. In GPx2 KO-M{\"a}usen liegt demnach bereits basal eine niedriggradige Entz{\"u}ndung vor. Dies unterstreicht, dass GPx2 vor allem eine wichtige antiinflammatorische Funktion im Darmepithel besitzt. Dem Mikron{\"a}hrstoff Selen werden protektive Funktionen in der Colonkanzerogenese zugeschrieben. In einem Mausmodell der Colitis-assoziierten Colonkanzerogenese wirkte GPx2 antiinflammatorisch und hemmte so die Tumorentstehung. Auf der anderen Seite wurden jedoch auch prokanzerogene Eigenschaften der GPx2 aufgedeckt. Deshalb sollte in dieser Arbeit untersucht werden, welchen Effekt ein GPx2 knockout in einem Modell der sporadischen, durch Azoxymethan (AOM) induzierten, Colonkanzerogenese hat. Im WT kam es in pr{\"a}neoplastischen L{\"a}sionen h{\"a}ufig zu einer erh{\"o}hten GPx2-Expression im Vergleich zur normalen Darmmucosa. Eine derartige Steigerung der GPx2-Expression wurde auch in der humanen Colonkanzerogenese beschrieben. Das Fehlen der GPx2 resultierte in einer verminderten Entstehung von Tumoren (-Se und ++Se) und pr{\"a}neoplastischen L{\"a}sionen (-Se und +Se). Somit f{\"o}rderte GPx2 die Tumorentstehung im AOM-Modell. Acht Stunden nach AOM-Gabe war im GPx2 KO-Colon im Vergleich zum WT eine erh{\"o}hte Apoptoserate in der Kryptenmitte (-Se, +Se), nicht jedoch im Kryptengrund oder in der ++Se-Gruppe zu beobachten. M{\"o}glicherweise wirkte GPx2 prokanzerogen, indem sie die effiziente Elimination gesch{\"a}digter Zellen in der Tumorinitiationsphase verhinderte. Eine {\"a}hnliche Wirkung w{\"a}re auch durch die erh{\"o}hte GPx2-Expression in der Promotionsphase denkbar. So k{\"o}nnte GPx2 proliferierende pr{\"a}neoplastische Zellen vor oxidativem Stress, Apoptosen, oder auch der Antitumorimmunit{\"a}t sch{\"u}tzen. Dies k{\"o}nnte durch ein Zusammenwirken mit anderen Selenoproteinen wie GPx1 und Thioredoxinreduktasen, f{\"u}r die ebenfalls auch prokanzerogene Funktionen beschrieben wurden, verst{\"a}rkt werden. Eine wichtige Rolle k{\"o}nnte hier die Modulation des Redoxstatus in Tumorzellen spielen. Die Variation des Selengehalts der Di{\"a}t hatte im WT einen eher U-f{\"o}rmigen Effekt. So traten in der -Se und ++Se-Gruppe tendenziell mehr und gr{\"o}ßere Tumore auf, als in der +Se Gruppe. Zusammenfassend sch{\"u}tzt GPx2 also die proliferierenden Zellen des Kryptengrundes. Sie k{\"o}nnte jedoch auch proliferierende transformierte Zellen sch{\"u}tzen und so die sporadische, AOM-induzierte Colonkanzerogenese f{\"o}rdern. In einem Modell der Colitis-assoziierten Colonkanzerogenese hatte GPx2 auf Grund ihrer antiinflammatorischen Wirkung einen gegenteiligen Effekt und hemmte die Tumorentstehung. Die Rolle der GPx2 in der Colonkanzerogenese ist also abh{\"a}ngig vom zugrunde liegenden Mechanismus und wird maßgeblich von der Beteiligung einer Entz{\"u}ndung bestimmt.}, language = {de} } @phdthesis{Mabrok2013, author = {Mabrok, Hoda Hussein Bakr}, title = {Protective role of lignan-converting bacteria on chemically-induced breast cancer in gnotobiotic rats}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64933}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Enterolignans (enterodiol and enterolactone) exhibit structural similarity to estradiol and have therefore been hypothesized to modulate hormone related cancers such as breast cancer. The bioactivation of the plant lignan secoisolariciresinol diglucoside (SDG) requires the transformation by intestinal bacteria including the deglycosylation of SDG to secoisolariciresinol (SECO) followed by demethylation and dehydroxylation of SECO to enterodiol (ED). Finally, ED is dehydrogenated to enterolactone (EL). It is unclear whether the bacterial activation of SDG to ED and EL is crucial for the cancer preventing effects of dietary lignans. The possible protective effect of bacterial lignan transformation on a 7,12 dimethylbenz(a)anthracene (DMBA)-induced breast cancer in gnotobiotic rats was investigated. Germ-free rats were associated with a defined lignan-converting consortium (Clostridium saccharogumia, Blautia producta, Eggerthella lenta, and Lactonifactor longoviformis). The rats colonized with lignan-converting bacteria consortium (LCC) were fed a lignan-rich flaxseed diet and breast cancer was chemical induced. Identically treated germ-free rats served as control. All bacteria of the consortium successfully colonized the intestine of the LCC rats. The plant lignan SDG was converted into the enterolignans ED and EL in the LCC rats but not in the germ-free rats. This transformation did not influence cancer incidence but significantly decreased tumor numbers per tumor-bearing rat, and tumor size. Cell proliferation was significantly inhibited and apoptosis was significantly induced in LCC rats. No differences between LCC and control rats were observed in the expression of the genes encoding the estrogen receptors (ERα and ERβ) and G-coupled protein receptor 30 (GPR30). Similar findings were observed for both insulin-like growth factor 1 (IGF-1) and epidermal growth factor receptor (EGFR) genes involved in tumor growth. Proteome analysis revealed that 24 proteins were differentially expressed in tumor tissue from LCC and germ-free. RanBP-type and C3HC4-type zinc finger-containing protein 1 (RBCK1) and poly(rC)-binding protein 1 (PBCP1) were down-regulated by 3.2- and 2.0-fold, respectively. These proteins are associated with cell proliferation. The activity of selected enzymes involved in the degradation of oxidants in plasma and liver was significantly increased in the LCC rats. However, plasma and liver concentrations of reduced glutathione (non-enzymatic antioxidant) and malondialdehyde (oxidative stress marker) did not differ between the groups. In conclusion, the bacterial conversion of plant lignan to enterolignans beneficially influences their anti-cancer effect. However, the mechanisms involved in these effects remain elusive.}, language = {en} } @article{GereckeMascherGottschalketal.2013, author = {Gerecke, Christian and Mascher, Conny and Gottschalk, Uwe and Kleuser, Burkhard and Scholtka, Bettina}, title = {Ultrasensitive detection of unknown colon cancer-initiating mutations using the example of the adenomatous polyposis coli gene}, series = {Cancer prevention research}, volume = {6}, journal = {Cancer prevention research}, number = {9}, publisher = {American Association for Cancer Research}, address = {Philadelphia}, issn = {1940-6207}, doi = {10.1158/1940-6207.CAPR-13-0145}, pages = {898 -- 907}, year = {2013}, abstract = {Detection of cancer precursors contributes to cancer prevention, for example, in the case of colorectal cancer. To record more patients early, ultrasensitive methods are required for the purpose of noninvasive precursor detection in body fluids. Our aim was to develop a method for enrichment and detection of known as well as unknown driver mutations in the Adenomatous polyposis coli (APC) gene. By coupled wild-type blocking (WTB) PCR and high-resolution melting (HRM), referred to as WTB-HRM, a minimum detection limit of 0.01\% mutant in excess wild-type was achieved according to as little as 1 pg mutated DNA in the assay. The technique was applied to 80 tissue samples from patients with colorectal cancer (n = 17), adenomas (n = 50), serrated lesions (n = 8), and normal mucosa (n = 5). Any kind of known and unknown APC mutations (deletions, insertions, and base exchanges) being situated inside the mutation cluster region was distinguishable from wild-type DNA. Furthermore, by WTB-HRM, nearly twice as many carcinomas and 1.5 times more precursor lesions were identified to be mutated in APC, as compared with direct sequencing. By analyzing 31 associated stool DNA specimens all but one of the APC mutations could be recovered. Transferability of the WTB-HRM method to other genes was proven using the example of KRAS mutation analysis. In summary, WTB-HRM is a new approach for ultrasensitive detection of cancer-initiating mutations. In this sense, it appears especially applicable for noninvasive detection of colon cancer precursors in body fluids with excess wild-type DNA like stool. Cancer Prev Res; 6(9); 898-907. (C) 2013 AACR.}, language = {en} } @article{NeuschaeferRubePatheNeuschaeferRubeHippenstieletal.2013, author = {Neusch{\"a}fer-Rube, Frank and Pathe-Neusch{\"a}fer-Rube, A. and Hippenstiel, S. and Kracht, M. and P{\"u}schel, Gerhard Paul}, title = {NF-kB-dependent IL-8 induction by prostaglandin EP2 receptors EP1 and EP4}, series = {British journal of pharmacology : journal of The British Pharmacological Society}, volume = {168}, journal = {British journal of pharmacology : journal of The British Pharmacological Society}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0007-1188}, doi = {10.1111/j.1476-5381.2012.02182.x}, pages = {704 -- 717}, year = {2013}, abstract = {Background and Purpose Recent studies suggested a role for PGE2 in the expression of the chemokine IL-8. PGE2 signals via four different GPCRs, EP1-EP4. The role of EP1 and EP4 receptors for IL-8 induction was studied in HEK293 cells, overexpressing EP1 (HEK-EP1), EP4 (HEK-EP4) or both receptors (HEK-EP1 + EP4). Experimental Approach IL-8 mRNA and protein induction and IL-8 promoter and NF-?B activation were assessed in EP expressing HEK cells. Key Results In HEK-EP1 and HEK-EP1 + EP4 but not HEK or HEK-EP4 cells, PGE2 activated the IL-8 promoter and induced IL-8 mRNA and protein synthesis. Stimulation of HEK-EP1 + EP4 cells with an EP1-specific agonist activated IL-8 promoter and induced IL-8 mRNA and protein, whereas a specific EP4 agonist neither activated the IL-8 promoter nor induced IL-8 mRNA and protein synthesis. Simultaneous stimulation of HEK- EP1 + EP4 cells with both agonists activated IL-8 promoter and induced IL-8 mRNA to the same extent as PGE2. In HEK-EP1 + EP4 cells, PGE2-mediated IL-8 promoter activation and IL-8 mRNA induction were blunted by inhibition of I?B kinase. PGE2 activated NF-?B in HEK-EP1, HEK-EP4 and HEK-EP1 + EP4 cells. In HEK-EP1 + EP4 cells, simultaneous activation of both receptors was needed for maximal PGE2-induced NF-?B activation. PGE2-stimulated NF-?B activation by EP1 was blocked by inhibitors of PLC, calcium-signalling and Src-kinase, whereas that induced by EP4 was only blunted by Src-kinase inhibition. Conclusions and Implications These findings suggest that PGE2-mediated NF-?B activation by simultaneous stimulation of EP1 and EP4 receptors induces maximal IL-8 promoter activation and IL-8 mRNA and protein induction.}, language = {en} } @article{JbeilySuckertGonnertetal.2013, author = {Jbeily, Nayla and Suckert, Iris and Gonnert, Falk A. and Acht, Benedikt and Bockmeyer, Clemens L. and Grossmann, Sascha D. and Blaess, Markus F. and L{\"u}th, Anja and Deigner, Hans-Peter and Bauer, Michael and Claus, Ralf A.}, title = {Hyperresponsiveness of mice deficient in plasma-secreted sphingomyelinase reveals its pivotal role in early phase of host response}, series = {Journal of lipid research}, volume = {54}, journal = {Journal of lipid research}, number = {2}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0022-2275}, doi = {10.1194/jlr.M031625}, pages = {410 -- 424}, year = {2013}, abstract = {Plasma secretion of acid sphingomyelinase is a hallmark of cellular stress response resulting in the formation of membrane embedded ceramide-enriched lipid rafts and the reorganization of receptor complexes. Consistently, decompartmentalization of ceramide formation from inert sphingomyelin has been associated with signaling events and regulation of the cellular phenotype. Herein, we addressed the question of whether the secretion of acid sphingomyelinase is involved in host response during sepsis. We found an exaggerated clinical course in mice genetically deficient in acid sphingomyelinase characterized by an increased bacterial burden, an increased phagocytotic activity, and a more pronounced cytokine storm. Moreover, on a functional level, leukocyte-endothelial interaction was found diminished in sphingomyelinase-deficient animals corresponding to a distinct leukocytes' phenotype with respect to rolling and sticking as well as expression of cellular surface proteins.(jlr) We conclude that hydrolysis of membrane-embedded sphingomyelin, triggered by circulating sphingomyelinase, plays a pivotal role in the first line of defense against invading microorganisms. This function might be essential during the early phase of infection leading to an adaptive response of remote cells and tissues.-Jbeily, N., I. Suckert, F. A. Gonnert, B. Acht, C. L. Bockmeyer, S. D. Grossmann, M. F. Blaess, A. Lueth, H.-P. Deigner, M. Bauer, and R. A. Claus. Hyperresponsiveness of mice deficient in plasma-secreted sphingomyelinase reveals its pivotal role in early phase of host response. J. Lipid Res. 2013. 54: 410-424.}, language = {en} } @article{LotinunKivirantaMatsubaraetal.2013, author = {Lotinun, Sutada and Kiviranta, Riku and Matsubara, Takuma and Alzate, Jorge A. and Neff, Lynn and L{\"u}th, Anja and Koskivirta, Ilpo and Kleuser, Burkhard and Vacher, Jean and Vuorio, Eero and Horne, William C. and Baron, Roland}, title = {Osteoclast-specific cathepsin K deletion stimulates S1P-dependent bone formation}, series = {The journal of clinical investigation}, volume = {123}, journal = {The journal of clinical investigation}, number = {2}, publisher = {American Society for Clinical Investigation}, address = {Ann Arbor}, issn = {0021-9738}, doi = {10.1172/JCI64840}, pages = {666 -- 681}, year = {2013}, abstract = {Cathepsin K (CTSK) is secreted by osteoclasts to degrade collagen and other matrix proteins during bone resorption. Global deletion of Ctsk in mice decreases bone resorption, leading to osteopetrosis, but also increases the bone formation rate (BFR). To understand how Ctsk deletion increases the BFR, we generated osteoclast- and osteoblast-targeted Ctsk knockout mice using floxed Ctsk alleles. Targeted ablation of Ctsk in hematopoietic cells, or specifically in osteoclasts and cells of the monocyte-osteoclast lineage, resulted in increased bone volume and BFR as well as osteoclast and osteoblast numbers. In contrast, targeted deletion of Ctsk in osteoblasts had no effect on bone resorption or BFR, demonstrating that the increased BFR is osteoclast dependent. Deletion of Ctsk in osteoclasts increased their sphingosine kinase 1 (Sphk1) expression. Conditioned media from Ctsk-deficient osteoclasts, which contained elevated levels of sphingosine-l-phosphate (S1P), increased alkaline phosphatase and mineralized nodules in osteoblast cultures. An S1P(1,3) receptor antagonist inhibited these responses. Osteoblasts derived from mice with Ctsk-deficient osteoclasts had an increased RANKL/OPG ratio, providing a positive feedback loop that increased the number of osteoclasts. Our data provide genetic evidence that deletion of CTSK in osteoclasts enhances bone formation in vivo by increasing the generation of osteoclast-derived S1P.}, language = {en} } @article{EspeRailaHenzeetal.2013, author = {Espe, Katharina M. and Raila, Jens and Henze, Andrea and Blouin, Katja and Schneider, Andreas and Schmiedeke, Daniel and Krane, Vera and Pilz, Stefan and Schweigert, Florian J. and Hocher, Berthold and Wanner, Christoph and Drechsler, Christiane}, title = {Low plasma alpha-tocopherol concentrations and adverse clinical outcomes in diabetic hemodialysis patients}, series = {Clinical journal of the American Society of Nephrology}, volume = {8}, journal = {Clinical journal of the American Society of Nephrology}, number = {3}, publisher = {American Society of Nephrology}, address = {Washington}, organization = {German Diabet \& Dialysis Study Inv}, issn = {1555-9041}, doi = {10.2215/CJN.04880511}, pages = {452 -- 458}, year = {2013}, abstract = {Background and objectives Trials with the antioxidant vitamin E have failed to show benefit in the general population. Considering the different causes of death in ESRD, this study investigated the association between plasma concentrations of alpha-tocopherol and specific clinical outcomes in diabetic hemodialysis patients. Design, settings, participants, \& measurements In 1046 diabetic hemodialysis patients (participants of the German Diabetes and Dialysis Study), alpha-tocopherol was measured in plasma by reversed-phase HPLC. By Cox regression analyses, hazard ratios were determined for prespecified end points according to baseline plasma alpha-tocopherol levels: sudden death (n=134), myocardial infarction (n=172), stroke (n=89), combined cardiovascular events (n=398), fatal infection (n=107), and all-cause mortality (n=508). Results Patients had a mean age of 66 8 years, and mean plasma alpha-tocopherol level was 22.8+/-9.6 mu mol/L. Levels of alpha-tocopherol were highly correlated to triglycerides (r=0.63, P<0.001). Patients in the lowest alpha-tocopherol quartile had (in unadjusted analyses) a 79\% higher risk of stroke and a 31\% higher risk of all-cause mortality compared with patients in the highest quartile. The associations were attenuated after adjustment for confounders (hazard ratio(stroke)=1.56, 95\% confidence interval=0.75-3.25; hazard ratio(mortality)=1.22, 95\% confidence interval=0.89-1.69, respectively). There was no association between alpha-tocopherol and myocardial infarction, sudden death, or infectious death. Conclusions Plasma alpha-tocopherol concentrations were not independently associated with cardiovascular outcomes, infectious deaths, or all-cause mortality in diabetic hemodialysis patients. The lack of association can partly be explained by a confounding influence of malnutrition, which should be considered in the planning of trials to reduce cardiovascular risk in dialysis patients.}, language = {en} } @misc{PolzinRassafBoehmetal.2013, author = {Polzin, Amin and Rassaf, Tienush and Boehm, Andreas and Lueth, Anja and Kleuser, Burkhard and Zeus, Tobias and Kelm, Malte and Kroemer, Heyo K. and Schroer, Karsten and Rauch, Bernhard H.}, title = {Aspirin inhibits release of platelet-derived sphingosine-1-phosphate in acute myocardial infarction}, series = {INTERNATIONAL JOURNAL OF CARDIOLOGY}, volume = {170}, journal = {INTERNATIONAL JOURNAL OF CARDIOLOGY}, number = {2}, publisher = {ELSEVIER IRELAND LTD}, address = {CLARE}, issn = {0167-5273}, doi = {10.1016/j.ijcard.2013.10.050}, pages = {E23 -- E24}, year = {2013}, language = {en} } @article{LuZengChenetal.2013, author = {Lu, Yong-Ping and Zeng, De-Ying and Chen, You-Peng and Liang, Xu-Jing and Xu, Jie-Ping and Huang, Si-Min and Lai, Zhi-Wei and Wen, Wang-Rong and von Websky, Karoline and Hocher, Berthold}, title = {Low birth weight is associated with lower respiratory tract infections in children with hand, foot, and mouth disease}, series = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, volume = {59}, journal = {Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion}, number = {9-10}, publisher = {Clin Lab Publ., Verl. Klinisches Labor}, address = {Heidelberg}, issn = {1433-6510}, doi = {10.7754/Clin.Lab.2012.120725}, pages = {985 -- 992}, year = {2013}, abstract = {Background: Low birth weight (LBW) might be a risk factor for acquiring lower respiratory tract infections (LRTIs) associated with disease related complications in early childhood. HFMD, a frequent viral infection in southern China, is a leading cause of lower respiratory tract infections in children. We analyzed whether LBW is a risk factor for children with HFMD to develop lower respiratory tract infections. Methods: A total of 298 children with HFMD, admitted to a hospital in Qingyuan city, Guangdong province, were recruited. Demographic data and clinical parameters such as serum glucose level and inflammatory markers including peripheral white blood cell count, serum C-reactive protein, and erythrocyte sedimentation rate were routinely collected on admission. Birth weight data were derived from birth records. Results: Mean birth weight (BW) was 167 g lower in patients with HFMD and LRTIs as compared to patients with solely HFMD (p = 0.022) and the frequency of birth weight below the tenth percentile was significantly higher in patients with HFMD and LRTIs (p = 0.002). Conclusions: The results of the study show that low birth weight is associated with a higher incidence of lower respiratory tract infections in young children with HFMD.}, language = {en} } @article{LiChenWangetal.2013, author = {Li, Jian and Chen, You-Peng and Wang, Zi-Neng and Liu, Tie-Bin and Chen, Dan and Dong, Yun-Peng and Hocher, Berthold}, title = {A functional fetal HSD11B2[CA]n microsatellite polymorphism is associated with maternal serum cortisol concentrations in pregnant women}, series = {Kidney \& blood pressure research : official organ of the Gesellschaft f{\"u}r Nephrologie}, volume = {38}, journal = {Kidney \& blood pressure research : official organ of the Gesellschaft f{\"u}r Nephrologie}, number = {1}, publisher = {Karger}, address = {Basel}, issn = {1420-4096}, doi = {10.1159/000355761}, pages = {132 -- 141}, year = {2013}, abstract = {Background/Aims: Cortisol plays an important role during pregnancy. It controls maternal glucose metabolism and fetal development. Cortisol metabolism is partially controlled by the 11b-HSD2. This enzyme is expressed in the kidney and human placenta. The activity of the enzyme is partially controlled by functional polymorphisms: the HSD11B2[CA]n microsatellite polymorphism. The impact of this functional gene polymorphism on cortisol metabolism and potential effects on the newborn's is unknown so far. Methods: In the current prospective birth cohort study in southern Asia, we analyzed the association of the HSD11B2[CA]n microsatellite polymorphisms in 187 mothers and their newborn's on maternal and newborn's serum cortisol concentrations. Results: Using multivariable regression analyses considering known confounding ( gestational age, newborn's gender, the labor uterine contraction states and the timing during the day of blood taking), we showed that the fetal HSD11B2[CA]n microsatellite polymorphisms in the first intron was related to maternal cortisol concentration ( R2=0.26, B=96.27, p=0.007), whereas as the newborn's cortisol concentrations were independent of fetal and maternal HSD11B2[CA] n microsatellite polymorphism. Conclusions: Our study showed for the first time that the fetal HSD11B2[CA]n microsatellite polymorphism of the HSD11B2 gene in healthy uncomplicated human pregnancy is associated with maternal cortisol concentration. This indicates that fetal genes controlling cortisol metabolism may affect maternal cortisol concentration and hence physiology in healthy pregnant women.}, language = {en} } @phdthesis{Barknowitz2013, author = {Barknowitz, Gitte}, title = {Serumalbumin- und H{\"a}moglobin-Addukte als Biomarker der Exposition gegen{\"u}ber Mutagenen Metaboliten von 1-Methoxy-Indolylmethyl-Glucosinolat-Untersuchungen in Maus und Menschen}, address = {Potsdam}, pages = {118 S.}, year = {2013}, language = {de} } @phdthesis{Lehmann2013, author = {Lehmann, Carsten}, title = {Glucosinolate in der entz{\"u}ndungsgetriebenen Kolonkanzerogenese - Induktion von Phase I und Phase II Enzymen sowie der Einfluss der intestinalen Mikrobiota}, address = {Potsdam}, pages = {117 S.}, year = {2013}, language = {de} } @article{KleinDarvinMeinkeetal.2013, author = {Klein, Julia and Darvin, Maxim E. and Meinke, Martina C. and Schweigert, Florian J. and M{\"u}ller, Kerstin E. and Lademann, J{\"u}rgen}, title = {Analyses of the correlation between dermal and blood carotenoids in female cattle by optical methods}, series = {Journal of biomedical optics}, volume = {18}, journal = {Journal of biomedical optics}, number = {6}, publisher = {SPIE}, address = {Bellingham}, issn = {1083-3668}, doi = {10.1117/1.JBO.18.6.061219}, pages = {6}, year = {2013}, abstract = {Herd health programs for the maintenance of welfare and productivity in cattle need efficient tools for monitoring the health of individual animals. Recent reports demonstrate that the oxidative status is related to various stress conditions in dairy cows. Biomarkers, among other carotenoids, could serve as indicators of stress originating from the environment (e.g., heat stress or sun radiation) or from the animal itself (e.g., disease). To date, only invasive in vitro tests are available to assess the oxidative status in cattle. The present study compares the results of optical noninvasive in vivo measurements of dermal carotenoids in cattle udder skin using an LED-based miniaturized spectroscopic system (MSS) with those obtained by photometric analysis of beta carotene in whole blood samples using a portable device. Correlations between the concentrations of dermal and blood carotenoids were calculated under consideration of the nutritional status of the animals. Significant correlation (R = 0.86) was found for cattle with a moderate to obese body condition. Thus, the blood and skin concentrations of the marker substance beta carotene are comparable under stable stress conditions of the cattle. This demonstrates that the MSS is suitable for noninvasive assessment of dermal carotenoid concentrations in cattle.}, language = {en} } @unpublished{HocherReichetzeder2013, author = {Hocher, Berthold and Reichetzeder, Christoph}, title = {Vitamin D and cardiovascular risk in postmenopausal women how to translate preclinical evidence into benefit for patients}, series = {Kidney international : official journal of the International Society of Nephrology}, volume = {84}, journal = {Kidney international : official journal of the International Society of Nephrology}, number = {1}, publisher = {Nature Publ. Group}, address = {New York}, issn = {0085-2538}, doi = {10.1038/ki.2013.139}, pages = {9 -- 11}, year = {2013}, abstract = {Preclinical work indicates that calcitriol restores vascular function by normalizing the endothelial expression of cyclooxygenase-2 and thromboxane-prostanoid receptors in conditions of estrogen deficiency and thus prevents the thromboxane-prostanoid receptor activation-induced inhibition of nitric oxide synthase. Since endothelial dysfunction is a key factor in the pathogenesis of cardiovascular diseases, this finding may have an important translational impact. It provides a clear rationale to use endothelial function in clinical trials aiming to find the optimal dose of vitamin D for the prevention of cardiovascular events in postmenopausal women.}, language = {en} } @inproceedings{HocherTsuprykovAlteretal.2013, author = {Hocher, Berthold and Tsuprykov, Oleg and Alter, Markus L. and von Websky, Karoline and Chaykovska, Lyubov and Antonenko, V. and Rahnenf{\"u}hrer, Jan and Klein, T. and Reichetzeder, Christoph}, title = {Linagliptin and the angiotensin II receptor blocker telmisartan show comparable efficacy but different renoprotective pathways in rats with 5/6 nephrectomy}, series = {Diabetologia : journal of the European Association for the Study of Diabetes (EASD)}, volume = {56}, booktitle = {Diabetologia : journal of the European Association for the Study of Diabetes (EASD)}, number = {15-16}, publisher = {Springer}, address = {New York}, issn = {0012-186X}, pages = {S66 -- S66}, year = {2013}, language = {en} } @article{MuenznerTuviaDeutschmannetal.2013, author = {M{\"u}nzner, Matthias and Tuvia, Neta and Deutschmann, Claudia and Witte, Nicole and Tolkachov, Alexander and Valai, Atijeh and Henze, Andrea and Sander, Leif E. and Raila, Jens and Schupp, Michael}, title = {Retinol-binding protein 4 and its membrane receptor STRA6 control adipogenesis by regulating cellular retinoid homeostasis and retinoic acid receptor alpha activity}, series = {Molecular and cellular biology}, volume = {33}, journal = {Molecular and cellular biology}, number = {20}, publisher = {American Society for Microbiology}, address = {Washington}, issn = {0270-7306}, doi = {10.1128/MCB.00221-13}, pages = {4068 -- 4082}, year = {2013}, abstract = {Retinoids are vitamin A (retinol) derivatives and complex regulators of adipogenesis by activating specific nuclear receptors, including the retinoic acid receptor (RAR) and retinoid X receptor (RXR). Circulating retinol-binding protein 4 (RBP4) and its membrane receptor STRA6 coordinate cellular retinol uptake. It is unknown whether retinol levels and the activity of RAR and RXR in adipocyte precursors are linked via RBP4/STRA6. Here, we show that STRA6 is expressed in precursor cells and, dictated by the apo-and holo-RBP4 isoforms, mediates bidirectional retinol transport that controls RAR alpha activity and subsequent adipocyte differentiation. Mobilization of retinoid stores in mice by inducing RBP4 secretion from the liver activated RAR alpha signaling in the precursor cell containing the stromal-vascular fraction of adipose tissue. Retinol-loaded holo-RBP4 blocked adipocyte differentiation of cultured precursors by activating RAR alpha. Remarkably, retinol-free apo-RBP4 triggered retinol efflux that reduced cellular retinoids, RAR alpha activity, and target gene expression and enhanced adipogenesis synergistically with ectopic STRA6. Thus, STRA6 in adipocyte precursor cells links nuclear RAR alpha activity to the circulating RBP4 isoforms, whose ratio in obese mice was shifted toward limiting the adipogenic potential of their precursors. This novel cross talk identifies a retinoldependent metabolic function of RBP4 that may have important implications for the treatment of obesity.}, language = {en} } @article{ChaykovskaAltervonWebskyetal.2013, author = {Chaykovska, Lyubov and Alter, Markus L. and von Websky, Karoline and Hohmann, Margarete and Tsuprykov, Oleg and Reichetzeder, Christoph and Kutil, Barbara and Kraft, Robin and Klein, Thomas and Hocher, Berthold}, title = {Effects of telmisartan and linagliptin when used in combination on blood pressure and oxidative stress in rats with 2-kidney-1-clip hypertension}, series = {Journal of hypertension}, volume = {31}, journal = {Journal of hypertension}, number = {11}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0263-6352}, doi = {10.1097/HJH.0b013e3283649b4d}, pages = {2290 -- 2299}, year = {2013}, abstract = {Objective:To investigate the effects of linagliptin alone and in combination with the angiotensin II receptor blocker (ARB), telmisartan on blood pressure (BP), kidney function, heart morphology and oxidative stress in rats with renovascular hypertension.Methods:Fifty-seven male Wistar rats underwent unilateral surgical stenosis of the renal artery [2-kidney-1-clip (2k1c) method]. Animals were randomly divided into four treatment groups (n=14-18 per group) receiving: telmisartan (10mg/kg per day in drinking water), linagliptin (89ppm in chow), combination (linagliptin 89ppm+telmisartan 10mg/kg per day) or placebo. An additional group of 12 rats underwent sham surgery. BP was measured one week after surgery. Hypertensive animals entered a 16-week dosing period. BP was measured 2, 4, 8, 12 and 16 weeks after the initiation of treatment. Blood and urine were tested for assessment of kidney function and oxidative stress 6, 10, 14 and 18 weeks after surgery. Blood and urine sampling and organ harvesting were finally performed.Results:Renal stenosis caused an increase in meanSD systolic BP as compared with the sham group (157.7 +/- 29.3 vs. 106.2 +/- 20.5mmHg, respectively; P<0.001). Telmisartan alone and in combination with linagliptin, normalized SBP (111.1 +/- 24.3mmHg and 100.4 +/- 13.9mmHg, respectively; P<0.001 vs. placebo). Telmisartan alone and in combination with linagliptin significantly prevented cardiac hypertrophy, measured by heart weight and myocyte diameter. Renal function measured by cystatin C was not affected by 2k1c surgery. Telmisartan significantly increased plasma concentration of cystatin C. 2k1c surgery initiated fibrosis in both kidneys. Telmisartan promoted further fibrotic changes in the clipped kidney, as measured by protein expression of Col1a1 and histology for interstitial fibrosis and glomerulosclerosis. In non-clipped kidneys, telmisartan demonstrated antifibrotic properties, reducing Col1a1 protein expression. Plasma levels of oxidized low-density lipoprotein were higher in the placebo-treated 2k1c rats as compared to sham-operated animals. The increase was abolished by linagliptin alone (P=0.03 vs. placebo) and in combination with telmisartan (P=0.02 vs. placebo). Combination therapy also significantly reduced plasma concentration of carbonyl proteins (P=0.04 vs. placebo).Conclusion:Inhibition of type 4 dipeptidyl peptidase with linagliptin did not counter BP-lowering effects of ARB in 2k1c rats. Linagliptin reduced lipid and protein oxidation in 2k1c rats, and this effect was BP-independent.}, language = {en} } @article{CarlsohnScharhagRosenbergerHeydenreichetal.2013, author = {Carlsohn, Anja and Scharhag-Rosenberger, Friederike and Heydenreich, Juliane and Mayer, Frank}, title = {Vitamin-D-Status of athletes with higher UV-exposure during training}, series = {Ern{\"a}hrungs-Umschau : Forschung \& Praxis}, volume = {60}, journal = {Ern{\"a}hrungs-Umschau : Forschung \& Praxis}, number = {10}, publisher = {Umschau-Zeitschriftenverl.}, address = {Frankfurt, Main}, issn = {0174-0008}, pages = {174 -- 176}, year = {2013}, language = {de} } @phdthesis{Ott2013, author = {Ott, Ina Mirijam}, title = {Alternative Therapieans{\"a}tze im murinen Modell der diabetischen Nephropathie : Stimulation der l{\"o}slichen Guanylatzyklase und Inhabition der Dipeptidylpeptidase-4}, address = {Potsdam}, pages = {116 S.}, year = {2013}, language = {de} } @article{TepelArmbrusterGroenetal.2013, author = {Tepel, Martin and Armbruster, Franz Paul and Groen, Hans Juergen and Scholze, Alexandra and Reichetzeder, Christoph and Roth, Heinz J{\"u}rgen and Hocher, Berthold}, title = {Nonoxidized, biologically active parathyroid hormone determines mortality in hemodialysis patients}, series = {The journal of clinical endocrinology \& metabolism}, volume = {98}, journal = {The journal of clinical endocrinology \& metabolism}, number = {12}, publisher = {Endocrine Society}, address = {Chevy Chase}, issn = {0021-972X}, doi = {10.1210/jc.2013-2139}, pages = {4744 -- 4751}, year = {2013}, abstract = {Background: It was shown that nonoxidized PTH (n-oxPTH) is bioactive, whereas the oxidation of PTH results in a loss of biological activity. Methods: In this study we analyzed the association of n-oxPTH on mortality in hemodialysis patients using a recently developed assay system. Results: Hemodialysis patients (224 men, 116 women) had a median age of 66 years. One hundred seventy patients (50\%) died during the follow-up period of 5 years. Median n-oxPTH levels were higher in survivors (7.2 ng/L) compared with deceased patients (5.0 ng/L; P = .002). Survival analysis showed an increased survival in the highest n-oxPTH tertile compared with the lowest n-oxPTH tertile (chi(2), 14.3; P = 0008). Median survival was 1702 days in the highest n-oxPTH tertile, whereas it was only 453 days in the lowest n-oxPTH tertile. Multivariable-adjusted Cox regression showed that higher age increased odds for death, whereas higher n-oxPTH reduced the odds for death. Another model analyzing a subgroup of patients with intact PTH (iPTH) concentrations at baseline above the upper normal range of the iPTH assay (70 ng/L) revealed that mortality in this subgroup was associated with oxidized PTH but not with n-oxPTH levels. Conclusions: The predictive power of n-oxPTH and iPTH on the mortality of hemodialysis patients differs substantially. Measurements of n-oxPTH may reflect the hormone status more precisely. The iPTH-associated mortality is most likely describing oxidative stress-related mortality.}, language = {en} } @phdthesis{Lippmann2013, author = {Lippmann, Doris}, title = {Der Einfluss glucosinolatreicher Brassica Gem{\"u}se auf das endogene Schutzsystem und die entz{\"u}ndungsassoziierte Colonkanzerogenese in der Maus}, address = {Potsdam}, pages = {105 S.}, year = {2013}, language = {de} } @article{HocherSharkovskaMarketal.2013, author = {Hocher, Berthold and Sharkovska, Yuliya and Mark, Michael and Klein, Thomas and Pfab, Thiemo}, title = {The novel DPP-4 inhibitors linagliptin and BI 14361 reduce infarct size after myocardial ischemia/reperfusion in rats}, series = {International journal of cardiology}, volume = {167}, journal = {International journal of cardiology}, number = {1}, publisher = {Elsevier}, address = {Clare}, issn = {0167-5273}, doi = {10.1016/j.ijcard.2011.12.007}, pages = {87 -- 93}, year = {2013}, abstract = {Background: Dipeptidylpeptidase-4 inhibition is reported to have beneficial effects on myocardial ischemia. Mechanisms might include a reduced degradation of stromal cell-derived factor-1 alpha with subsequent increased recruitment of circulating stem cells and/or incretin receptor-dependent pathways. This study evaluated the novel xanthine-based dipeptidylpeptidase-4 inhibitors linagliptin (BI 1356) and BI 14361 in cardiac ischemia. Methods: Male Wistar rats were pretreated with linagliptin or BI 14361 and subjected to ligation of the left anterior descending coronary artery for 30 min. Results: Dipeptidylpeptidase-4 inhibition significantly reduced the infarct size after 7 days (-27.7\%, p<0.05) and 8 weeks (-18.0\%, p<0.05). There was a significantly improved maximum rate of left ventricular pressure decline (dP/dt min) in linagliptin-treated animals 8 weeks after ischemia/reperfusion. Apart from that, treatment did not improve cardiac function as determined by echocardiography and cardiac catheterization. Immunohistological staining revealed an increased number of cells positive for stromal cell-derived factor-1 alpha, CXCR-4 and CD34 within and around the infarcted area of BI 14361-treated animals. Conclusions: Linagliptin and BI 14361 are able to reduce infarct size after myocardial ischemia. The immunohistological findings support the hypothesis that dipeptidylpeptidase-4 inhibition via reduced cleavage of stromal cell-derived factor-1 alpha might lead to an enhanced recruitment of CXCR-4+ circulating progenitor cells.}, language = {en} } @article{BoehmFloesserErmleretal.2013, author = {B{\"o}hm, Andreas and Fl{\"o}ßer, Anja and Ermler, Swen and Fender, Anke C. and L{\"u}th, Anja and Kleuser, Burkhard and Schr{\"o}r, Karsten and Rauch, Bernhard H.}, title = {Factor-Xa-induced mitogenesis and migration require sphingosine kinase activity and S1P formation in human vascular smooth muscle cells}, series = {Cardiovascular research}, volume = {99}, journal = {Cardiovascular research}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0008-6363}, doi = {10.1093/cvr/cvt112}, pages = {505 -- 513}, year = {2013}, abstract = {Sphingosine-1-phosphate (S1P) is a cellular signalling lipid generated by sphingosine kinase-1 (SPHK1). The aim of the study was to investigate whether the activated coagulation factor-X (FXa) regulates SPHK1 transcription and the formation of S1P and subsequent mitogenesis and migration of human vascular smooth muscle cells (SMC). FXa induced a time- (36 h) and concentration-dependent (330 nmol/L) increase of SPHK1 mRNA and protein expression in human aortic SMC, resulting in an increased synthesis of S1P. FXa-stimulated transcription of SPHK1 was mediated by the protease-activated receptor-1 (PAR-1) and PAR-2. In human carotid artery plaques, expression of SPHK1 was observed at SMC-rich sites and was co-localized with intraplaque FX/FXa content. FXa-induced SPHK1 transcription was attenuated by inhibitors of Rho kinase (Y27632) and by protein kinase C (PKC) isoforms (GF109203X). In addition, FXa rapidly induced the activation of the small GTPase Rho A. Inhibition of signalling pathways which regulate SPHK1 expression, inhibition of its activity or siRNA-mediated SPHK1 knockdown attenuated the mitogenic and chemotactic response of human SMC to FXa. These data suggest that FXa induces SPHK1 expression and increases S1P formation independent of thrombin and that this involves the activation of Rho A and PKC signalling. In addition to its key function in coagulation, this direct effect of FXa on human SMC may increase cell proliferation and migration at sites of vessel injury and thereby contribute to the progression of vascular lesions.}, language = {en} } @phdthesis{Gerecke2013, author = {Gerecke, Christian}, title = {Entwicklung eines hochsensitiven Verfahrens zur Detektion von Mutationen im Tumorsuppressor APC und Analyse des Methylierungsstatus der Genpromotoren von ITGA4, TFPI2 und Vimentin in humanen Kolongeweben und F{\"a}zes}, address = {Potsdam}, pages = {147 S.}, year = {2013}, language = {de} } @phdthesis{Doecke2013, author = {D{\"o}cke, Stephanie}, title = {Untersuchung von ausgew{\"a}hlten pathogenetischen Signalwegen der humanen nicht-alkoholischen Fettlebererkrankung}, address = {Potsdam}, pages = {113 S.}, year = {2013}, language = {de} } @phdthesis{Muehlenbruch2013, author = {M{\"u}hlenbruch, Kristin}, title = {Updating the german diabetes risk score - model extensions, validation and reclassification}, address = {Potsdam}, pages = {131 S.}, year = {2013}, language = {en} } @phdthesis{Seltmann2013, author = {Seltmann, Anne-Cathrin}, title = {Nutrigenetik der metabolischen Adaptation an eine isokalorische Hochfettdi{\"a}t bei gesunden Zwillingen}, address = {Potsdam}, pages = {157 S.}, year = {2013}, language = {de} } @inproceedings{HenzeRailaScholzeetal.2013, author = {Henze, Andrea and Raila, Jens and Scholze, Alexandra and Schweigert, Florian J. and Tepel, Martin}, title = {Administration of N-Acetylcyteine causes beneficial posttranslationalmodifications of transthyretin in hemodialysis patients}, series = {Nephrology, dialysis, transplantation}, volume = {28}, booktitle = {Nephrology, dialysis, transplantation}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0931-0509}, pages = {164 -- 164}, year = {2013}, language = {en} } @article{HorikoshiYaghootkarMookKanamorietal.2013, author = {Horikoshi, Momoko and Yaghootkar, Hanieh and Mook-Kanamori, Dennis O. and Sovio, Ulla and Taal, H. Rob and Hennig, Branwen J. and Bradfield, Jonathan P. and St Pourcain, Beate and Evans, David M. and Charoen, Pimphen and Kaakinen, Marika and Cousminer, Diana L. and Lehtimaki, Terho and Kreiner-Moller, Eskil and Warrington, Nicole M. and Bustamante, Mariona and Feenstra, Bjarke and Berry, Diane J. and Thiering, Elisabeth and Pfab, Thiemo and Barton, Sheila J. and Shields, Beverley M. and Kerkhof, Marjan and van Leeuwen, Elisabeth M. and Fulford, Anthony J. and Kutalik, Zoltan and Zhao, Jing Hua and den Hoed, Marcel and Mahajan, Anubha and Lindi, Virpi and Goh, Liang-Kee and Hottenga, Jouke-Jan and Wu, Ying and Raitakari, Olli T. and Harder, Marie N. and Meirhaeghe, Aline and Ntalla, Ioanna and Salem, Rany M. and Jameson, Karen A. and Zhou, Kaixin and Monies, Dorota M. and Lagou, Vasiliki and Kirin, Mirna and Heikkinen, Jani and Adair, Linda S. and Alkuraya, Fowzan S. and Al-Odaib, Ali and Amouyel, Philippe and Andersson, Ehm Astrid and Bennett, Amanda J. and Blakemore, Alexandra I. F. and Buxton, Jessica L. and Dallongeville, Jean and Das, Shikta and de Geus, Eco J. C. and Estivill, Xavier and Flexeder, Claudia and Froguel, Philippe and Geller, Frank and Godfrey, Keith M. and Gottrand, Frederic and Groves, Christopher J. and Hansen, Torben and Hirschhorn, Joel N. and Hofman, Albert and Hollegaard, Mads V. and Hougaard, David M. and Hyppoenen, Elina and Inskip, Hazel M. and Isaacs, Aaron and Jorgensen, Torben and Kanaka-Gantenbein, Christina and Kemp, John P. and Kiess, Wieland and Kilpelainen, Tuomas O. and Klopp, Norman and Knight, Bridget A. and Kuzawa, Christopher W. and McMahon, George and Newnham, John P. and Niinikoski, Harri and Oostra, Ben A. and Pedersen, Louise and Postma, Dirkje S. and Ring, Susan M. and Rivadeneira, Fernando and Robertson, Neil R. and Sebert, Sylvain and Simell, Olli and Slowinski, Torsten and Tiesler, Carla M. T. and Toenjes, Anke and Vaag, Allan and Viikari, Jorma S. and Vink, Jacqueline M. and Vissing, Nadja Hawwa and Wareham, Nicholas J. and Willemsen, Gonneke and Witte, Daniel R. and Zhang, Haitao and Zhao, Jianhua and Wilson, James F. and Stumvoll, Michael and Prentice, Andrew M. and Meyer, Brian F. and Pearson, Ewan R. and Boreham, Colin A. G. and Cooper, Cyrus and Gillman, Matthew W. and Dedoussis, George V. and Moreno, Luis A. and Pedersen, Oluf and Saarinen, Maiju and Mohlke, Karen L. and Boomsma, Dorret I. and Saw, Seang-Mei and Lakka, Timo A. and Koerner, Antje and Loos, Ruth J. F. and Ong, Ken K. and Vollenweider, Peter and van Duijn, Cornelia M. and Koppelman, Gerard H. and Hattersley, Andrew T. and Holloway, John W. and Hocher, Berthold and Heinrich, Joachim and Power, Chris and Melbye, Mads and Guxens, Monica and Pennell, Craig E. and Bonnelykke, Klaus and Bisgaard, Hans and Eriksson, Johan G. and Widen, Elisabeth and Hakonarson, Hakon and Uitterlinden, Andre G. and Pouta, Anneli and Lawlor, Debbie A. and Smith, George Davey and Frayling, Timothy M. and McCarthy, Mark I. and Grant, Struan F. A. and Jaddoe, Vincent W. V. and Jarvelin, Marjo-Riitta and Timpson, Nicholas J. and Prokopenko, Inga and Freathy, Rachel M.}, title = {New loci associated with birth weight identify genetic links between intrauterine growth and adult height and metabolism}, series = {Nature genetics}, volume = {45}, journal = {Nature genetics}, number = {1}, publisher = {Nature Publ. Group}, address = {New York}, organization = {MAGIC, Early Growth Genetics EGG}, issn = {1061-4036}, doi = {10.1038/ng.2477}, pages = {76 -- U115}, year = {2013}, abstract = {Birth weight within the normal range is associated with a variety of adult-onset diseases, but the mechanisms behind these associations are poorly understood(1). Previous genome-wide association studies of birth weight identified a variant in the ADCY5 gene associated both with birth weight and type 2 diabetes and a second variant, near CCNL1, with no obvious link to adult traits(2). In an expanded genome-wide association metaanalysis and follow-up study of birth weight (of up to 69,308 individuals of European descent from 43 studies), we have now extended the number of loci associated at genome-wide significance to 7, accounting for a similar proportion of variance as maternal smoking. Five of the loci are known to be associated with other phenotypes: ADCY5 and CDKAL1 with type 2 diabetes, ADRB1 with adult blood pressure and HMGA2 and LCORL with adult height. Our findings highlight genetic links between fetal growth and postnatal growth and metabolism.}, language = {en} } @phdthesis{Schumann2013, author = {Schumann, Sara}, title = {Influence of intestinal inflammation on bacterial protein expression in monoassociated mice}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67757}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Background: Increased numbers of intestinal E. coli are observed in inflammatory bowel disease, but the reasons for this proliferation and it exact role in intestinal inflammation are unknown. Aim of this PhD-project was to identify E. coli proteins involved in E. coli's adaptation to the inflammatory conditions in the gut and to investigate whether these factors affect the host. Furthermore, the molecular basis for strain-specific differences between probiotic and harmful E. coli in their response to intestinal inflammation was investigated. Methods: Using mice monoassociated either with the adherent-invasive E. coli (AIEC) strain UNC or the probiotic E. coli Nissle, two different mouse models of intestinal inflammation were analysed: On the one hand, severe inflammation was induced by treating mice with 3.5\% dextran sodium sulphate (DSS). On the other hand, a very mild intestinal inflammation was generated by associating interleukin 10-deficient (IL-10-/-) mice with E. coli. Differentially expressed proteins in the E. coli strains collected from caecal contents of these mice were identified by two-dimensional fluorescence difference gel electrophoresis. Results DSS-experiment: All DSS-treated mice revealed signs of a moderate caecal and a severe colonic inflammation. However, mice monoassociated with E. coli Nissle were less affected. In both E. coli strains, acute inflammation led to a downregulation of pathways involved in carbohydrate breakdown and energy generation. Accordingly, DSS-treated mice had lower caecal concentrations of bacterial fermentation products than the control mice. Differentially expressed proteins also included the Fe-S cluster repair protein NfuA, the tryptophanase TnaA, and the uncharacterised protein YggE. NfuA was upregulated nearly 3-fold in both E. coli strains after DSS administration. Reactive oxygen species produced during intestinal inflammation damage Fe-S clusters and thereby lead to an inactivation of Fe-S proteins. In vitro data indicated that the repair of Fe-S proteins by NfuA is a central mechanism in E. coli to survive oxidative stress. Expression of YggE, which has been reported to reduce the intracellular level of reactive oxygen species, was 4- to 8-fold higher in E. coli Nissle than in E. coli UNC under control and inflammatory conditions. In vitro growth experiments confirmed these results, indicating that E. coli Nissle is better equipped to cope with oxidative stress than E. coli UNC. Additionally, E. coli Nissle isolated from DSS-treated and control mice had TnaA levels 4- to 7-fold higher than E. coli UNC. In turn, caecal indole concentrations resulting from cleavage of tryptophan by TnaA were higher in E. coli Nissle- associated control mice than in the respective mice associated with E. coli UNC. Because of its anti-inflammatory effect, indole is hypothesised to be involved in the extension of the remission phase in ulcerative colitis described for E. coli Nissle. Results IL-10-/--experiment: Only IL-10-/- mice monoassociated with E. coli UNC for 8 weeks exhibited signs of a very mild caecal inflammation. In agreement with this weak inflammation, the variations in the bacterial proteome were small. Similar to the DSS-experiment, proteins downregulated by inflammation belong mainly to the central energy metabolism. In contrast to the DSS-experiment, no upregulation of chaperone proteins and NfuA were observed, indicating that these are strategies to overcome adverse effects of strong intestinal inflammation. The inhibitor of vertebrate C-type lysozyme, Ivy, was 2- to 3-fold upregulated on mRNA and protein level in E. coli Nissle in comparison to E. coli UNC isolated from IL-10-/- mice. By overexpressing ivy, it was demonstrated in vitro that Ivy contributes to a higher lysozyme resistance observed for E. coli Nissle, supporting the role of Ivy as a potential fitness factor in this E. coli strain. Conclusions: The results of this PhD-study demonstrate that intestinal bacteria sense even minimal changes in the health status of the host. While some bacterial adaptations to the inflammatory conditions are equal in response to strong and mild intestinal inflammation, other reactions are unique to a specific disease state. In addition, probiotic and colitogenic E. coli differ in their response to the intestinal inflammation and thereby may influence the host in different ways.}, language = {en} } @article{SchaperDickhautJaptoketal.2013, author = {Schaper, Katrin and Dickhaut, Jeannette and Japtok, Lukasz and Kietzmann, Manfred and Mischke, Reinhard and Kleuser, Burkhard and B{\"a}umer, Wolfgang}, title = {Sphingosine-1-phosphate exhibits anti-proliferative and anti-inflammatory effects in mouse models of psoriasis}, series = {Journal of dermatological scienc}, volume = {71}, journal = {Journal of dermatological scienc}, number = {1}, publisher = {Elsevier}, address = {Clare}, issn = {0923-1811}, doi = {10.1016/j.jdermsci.2013.03.006}, pages = {29 -- 36}, year = {2013}, abstract = {Background: It has been indicated that the sphingolipid sphingosine-1-phosphate (SIP) restrains the ability of dendritic cells to migrate to lymph nodes. Furthermore SIP has been demonstrated to inhibit cell growth in human keratinocytes. However, only little is known about the effect of S1P in hyperproliferative and inflammatory in vivo models. Objective: In this study, locally acting SIP was explored in different experimental mouse models of psoriasis vulgaris. Methods: S1P and FTY720 were tested in the imiquimod-induced psoriasis mouse model, the mouse tail assay and a pilot study of the severe combined immunodeficiency mice (SCID). Results: In the imiquimod model the positive control diflorasone diacetate and S1P, but not FTY720 reduced the imiquimod-induced epidermal hyperproliferation of the ear skin. This effect was confirmed in the SCID model, where S1P treated skin from patients suffering from psoriasis showed a decrease in epidermal thickness compared to vehicle. In the imiquimod model, there was also significant inhibition of ear swelling and a moderate reduction of inflammatory cell influx and oedema formation in ear skin by SIP treatment. The inflammatory response on the back skin was, however, only reduced by diflorasone diacetate. In the mouse tail assay, the influence of S1P and FTY720 in stratum granulosum formation was tested compared to the positive control calcipotriol. Whereas topical administration of calcipotriol led to a low but significant increase of stratum granulosum, S1P and FTY720 lacked such an effect. Conclusion: Taken together, these results imply that topical administration of SIP might be a new option for the treatment of mild to moderate psoriasis lesions.}, language = {en} } @phdthesis{Neymeyer2013, author = {Neymeyer, Hanna}, title = {Annexin A1 im chronischen Nierenversagen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69670}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Die Expansion des renalen Tubulointerstitiums aufgrund einer Akkumulation zellul{\"a}rer Bestandteile und extrazellul{\"a}rer Matrix ist eine charakteristische Eigenschaft der chronischen Nierenerkrankung (CKD) und f{\"u}hrt zu einer Progression der Erkrankung in Richtung eines terminalen Nierenversagens. Die Fibroblasten Proliferation und ihre Transformation hin zum sekretorischen Myofibroblasten-Ph{\"a}notyp stellen hierbei Schl{\"u}sselereignisse dar. Signalprozesse, die zur Induktion der Myofibroblasten f{\"u}hren, werden aktiv beforscht um anti-fibrotische Therapieans{\"a}tze zu identifizieren. Das anti-inflammatorische Protein Annexin A1 und sein Rezeptor Formyl-Peptid Rezeptor 2 (FPR2) wurden in verschiedenen Organsystemen mit der Regulation von Fibroblastenaktivit{\"a}t in Verbindung gebracht, jedoch wurden ihre Expression und Funktion bei renalen fibrotischen Erkrankungen bisher nicht untersucht. Ziel der aktuellen Studie war daher die Untersuchung der renalen Annexin A1- und FPR2-Expression in einem Tiermodell des chronischen Nierenversagens, sowie die Charakterisierung der funktionellen Rolle von Annexin A1 in der Regulation des Fibroblasten Ph{\"a}notyps und ihrer Syntheseleistung. Dazu wurden neugeborene Sprague-Dawley Ratten in den ersten zwei Wochen ihres Lebens entweder mit Vehikel oder mit einem Angiotensin II Typ I Rezeptor Antagonisten behandelt und ohne weitere Intervention bis zu einem Alter von 11 Monaten (CKD Ratten) gehalten. Die Regulation und Lokalisation von Annexin A1 und FPR2 wurden mit Hilfe von Real-Time PCR und Immunhistochemie erfasst. Annexin A1- und FPR2-exprimierende Zellen wurden weiter durch Doppelimmunfluoreszenzf{\"a}rbungen charakterisiert. Gef{\"a}rbt wurde mit Antik{\"o}rpern gegen endotheliale Zellen (rat endothelial cell antigen), Makrophagen (CD 68), Fibroblasten (CD73) und Myofibroblasten (alpha-smooth muscle actin (α-sma)). Zellkulturstudien wurden an immortalisierten renalen kortikalen Fibroblasten aus Wildtyp- und Annexin A1-defizienten M{\"a}usen, sowie an etablierten humanen und murinen renalen Fibrolasten durchgef{\"u}hrt. Eine {\"U}berexpression von Annexin A1 wurde durch eine stabile Transfektion erreicht. Die Expression von Annexin A1, α-sma und Kollagen 1α1 wurde durch Real-Time PCR, Western Blot und Immuhistochemie erfasst. Die Sekretion des Annexin A1 Proteins wurde nach TCA-F{\"a}llung des Zellkultur{\"u}berstandes im Western Blot untersucht. Wie zu erwarten zeigten die CKD Ratten eine geringere Anzahl an Nephronen mit deutlicher glomerul{\"a}ren Hypertrophie. Der tubulointerstitielle Raum war durch fibrill{\"a}res Kollagen, aktivierte Fibroblasten und inflammatorische Zellen expandiert. Parallel dazu war die mRNA Expression von Annexin A1 und Transforming growth factor beta (TGF-β) signifikant erh{\"o}ht. Die Annexin A1-Lokalisation mittels Doppelimmunfluorsezenz identifizierte eine große Anzahl von CD73-positiven kortikalen Fibroblasten und eine Subpopulation von Makrophagen als Annexin A1-positiv. Die Annexin A1-Menge in Myofibroblasten und renalen Endothelien war gering. FPR2 konnte in der Mehrzahl der renalen Fibroblasten, in Myofibroblasten, in einer Subpopulation von Makrophagen und in renalen Epithelzellen nachgewiesen werden. Eine Behandlung der murinen Fibroblasten mit dem pro-fibrotischen Zytokin TGF-β f{\"u}hrte zu einem parallelen Anstieg der α-sma-, Kollagen 1α1- und Annexin A1-Biosynthese und zu einer gesteigerten Sekretion von Annexin A1. Eine {\"U}berexpression von Annexin A1 in murinen Fibroblasten reduzierte das Ausmaß der TGF-β induzierten α-sma- und Kollagen 1α1-Biosynthese. Fibroblasten aus Annexin A1-defizienten M{\"a}usen zeigten einen starken Myofibroblasten-Ph{\"a}notyp mit einer gesteigerten Expression an α-sma und Kollagen 1α1. Der Einsatz eines Peptidantagonisten des FPR2 (WRW4) resultierte in einer Stimulation der α-sma-Biosynthese, was die Vermutung nahe legte, dass Annexin A1 FPR2-vermittelt anti-fibrotische Effekte hat. Zusammenfassend zeigen diese Ergebnisse, dass renale kortikale Fibroblasten eine Hauptquelle des Annexin A1 im renalen Interstitium und einen Ansatzpunkt f{\"u}r Annexin A1-Signalwege in der Niere darstellen. Das Annexin A1/FPR2-System k{\"o}nnte daher eine wichtige Rolle in der Kontrolle des Fibroblasten Ph{\"a}notyp und der Fibroblasten Aktivit{\"a}t spielen und daher einen neuen Ansatz f{\"u}r die anti-fibrotischen pharmakologischen Strategien in der Behandlung des CKD darstellen.}, language = {de} } @phdthesis{Slezak2013, author = {Slezak, Kathleen}, title = {Impact of intestinal bacteria on the anatomy and physiology of the intestinal tract in the PRM/Alf mouse model}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68946}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Introduction: Intestinal bacteria influence gut morphology by affecting epithelial cell proliferation, development of the lamina propria, villus length and crypt depth [1]. Gut microbiota-derived factors have been proposed to also play a role in the development of a 30 \% longer intestine, that is characteristic of PRM/Alf mice compared to other mouse strains [2, 3]. Polyamines and SCFAs produced by gut bacteria are important growth factors, which possibly influence mucosal morphology, in particular villus length and crypt depth and play a role in gut lengthening in the PRM/Alf mouse. However, experimental evidence is lacking. Aim: The objective of this work was to clarify the role of bacterially-produced polyamines on crypt depth, mucosa thickness and epithelial cell proliferation. For this purpose, C3H mice associated with a simplified human microbiota (SIHUMI) were compared with mice colonized with SIHUMI complemented by the polyamine-producing Fusobacterium varium (SIHUMI + Fv). In addition, the microbial impact on gut lengthening in PRM/Alf mice was characterized and the contribution of SCFAs and polyamines to this phenotype was examined. Results: SIHUMI + Fv mice exhibited an up to 1.7 fold higher intestinal polyamine concentration compared to SIHUMI mice, which was mainly due to increased putrescine concentrations. However, no differences were observed in crypt depth, mucosa thickness and epithelial proliferation. In PRM/Alf mice, the intestine of conventional mice was 8.5 \% longer compared to germfree mice. In contrast, intestinal lengths of C3H mice were similar, independent of the colonization status. The comparison of PRM/Alf and C3H mice, both associated with SIHUMI + Fv, demonstrated that PRM/Alf mice had a 35.9 \% longer intestine than C3H mice. However, intestinal SCFA and polyamine concentrations of PRM/Alf mice were similar or even lower, except N acetylcadaverine, which was 3.1-fold higher in PRM/Alf mice. When germfree PRM/Alf mice were associated with a complex PRM/Alf microbiota, the intestine was one quarter longer compared to PRM/Alf mice colonized with a C3H microbiota. This gut elongation correlated with levels of the polyamine N acetylspermine. Conclusion: The intestinal microbiota is able to influence intestinal length dependent on microbial composition and on the mouse genotype. Although SCFAs do not contribute to gut elongation, an influence of the polyamines N acetylcadaverine and N acetylspermine is conceivable. In addition, the study clearly demonstrated that bacterial putrescine does not influence gut morphology in C3H mice.}, language = {en} } @phdthesis{Junick2013, author = {Junick, Jana}, title = {Einfluss von Synbiotika auf die intestinale Mikrobiota gesunder Neugeborener}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69525}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Hintergrund: Gestillte Kinder haben im Vergleich zu nicht gestillten Kindern eine geringere Inzidenz von gastrointestinalen Infektionen und atopischen Erkrankungen. Man geht davon aus, dass der gesundheitsf{\"o}rdernde Effekt der Muttermilch teilweise {\"u}ber die intestinale Mikrobiota vermittelt wird. Diese ist in Stillkindern durch eine geringe Diversit{\"a}t und einen hohen Anteil an Bifidobakterien charakterisiert. Neueste Ans{\"a}tze in der Weiterentwicklung industriell hergestellter S{\"a}uglingsnahrung zielen darauf ab, eine intestinale Mikrobiota zu f{\"o}rdern, die der von gestillten Kindern {\"a}hnelt. Die Supplementation von S{\"a}uglingsnahrung mit Probiotika (lebende Mikroorganismen) oder Pr{\"a}biotika (unverdauliche Kohlenhydrate, die als Energiesubstrat f{\"u}r probiotische Bakterien dienen) k{\"o}nnte die bifidogene und antipathogene, aber auch immunmodulierende Wirkung der Muttermilch nachahmen. Aufgrund unterschiedlicher Interaktionen mit der Darmmikrobiota und dem Immunsystem fokussiert man mit der gleichzeitigen Gabe von Pro- und Pr{\"a}biotika (Synbiotika) eine synergistische Wirkung an. Zielstellung und Studiendesign: In einer randomisiert-kontrollierten, klinischen Studie wurde untersucht, ob sich in den ersten drei Lebensmonaten von gesunden und termingerecht geborenen Kindern mit einer Synbiotikum-haltigen S{\"a}uglingsnahrung eine intestinale Mikrobiota etabliert, die der von gestillten Kindern gleicht. Das Synbiotikum setzte sich aus Bifidobacterium animalis ssp. lactis CNCM I 3446 ({\"a}ltere Bezeichnung B. lactis BB-12) und Kuhmilcholigosacchariden zusammen. Die Studie umfasste zwei Gruppen von Kindern, die eine S{\"a}uglingsnahrung mit (SYN-Gruppe, n=21) oder ohne Supplement (KON-Gruppe, n=18) erhielten. Gestillte Kinder dienten als Referenz (REF-Gruppe, n=23). Um die Diversit{\"a}t der Bifidobakterien auf Speziesebene umfassend zu charakterisieren, wurden quantitative Real-Time PCR (qPCR)-Verfahren, basierend auf dem single-copy groEL als phylogenetisches Zielgen, zur spezifischen Quantifizierung von zw{\"o}lf Bifidobakterienspezies in humanen F{\"a}zes entwickelt und validiert. Ergebnisse: Die supplementierte S{\"a}uglingsnahrung war gut vertr{\"a}glich und unterst{\"u}tzte eine gesunde Entwicklung; vergleichbare anthropometrische Daten von SYN- und REF-Gruppe. Das Synbiotikum stimulierte selektiv das Wachstum von Laktobazillen und Bifidobakterien. Die Zellzahl f{\"u}r Laktobazillen der SYN-Gruppe war zur REF-Gruppe {\"a}quivalent (9,07±0,32 versus 9,90±0,27 log10 Zellen/g F{\"a}zes TM [MW±SEM]; p<0,0019; {\"A}quivalenzdifferenz von 1 log10 Zellen/g F{\"a}zes TM) und h{\"o}her als in der KON-Gruppe (8,27±0,31 log10 Zellen/g F{\"a}zes TM [MW±SEM]). Die Zellzahl f{\"u}r Bifidobakterien war in der SYN-Gruppe am h{\"o}chsten (11,54±0,05 versus 11,00±0,17 [REF-Gruppe] und 10,54±0,24 [KON-Gruppe] log10 Zellen/g F{\"a}zes TM [MW±SEM]). In der SYN-Gruppe wurde die h{\"o}chste Anzahl an Bifidobakterienspezies erfasst (167 mit [128 ohne] B. animalis in 56 F{\"a}zesproben versus 98 und 93 in jeweils 51 F{\"a}zesproben der REF- und KON-Gruppe). Neben Kinder-typischen Spezies wie B. bifidum und B. breve wurden auch Spezies, die f{\"u}r Erwachsene charakteristisch sind (B. adolescentis), h{\"a}ufiger in der SYN-Gruppe als in den Vergleichsgruppen nachgewiesen. Der pH-Wert in F{\"a}zes von Kindern aus der SYN-Gruppe war niedriger als der aus der KON-Gruppe (6,07±0,20 versus 6,45±0,17 [MW±SEM]) und n{\"a}her an dem von gestillten Kindern mit 5,29±0,12 (MW±SEM). Schlussfolgerung: Die Supplementation einer S{\"a}uglingsnahrung mit dem Synbiotikum aus CNCM I-3446 und Kuhmilcholigosacchariden f{\"u}hrte zu einer Angleichung in der Zusammensetzung der intestinalen Mikrobiota und des f{\"a}kalen pH-Wertes an gestillte Kinder. Die in dieser Arbeit entwickelten groEL-basierten qPCR-Verfahren erlaubten eine spezifische und genaue Analyse der Bifidobakterienpopulation unter dem Einfluss eines Synbiotikums.}, language = {de} } @phdthesis{Khalil2013, author = {Khalil, Mahmoud Abd Elhamid}, title = {Improvement of stability and bioavailability of lutein and lutein ester in emulsion-based delivery systems}, address = {Potsdam}, pages = {145 S.}, year = {2013}, language = {en} }