TY  - THES
A1  - Bourdet, Patric
T1  - Entwicklung einer auf Antikörpern basierten Therapie von chirurgischen Infektionen verursacht durch methicillinresistente und -sensible Staphylococcus aureus (MRSA und MSSA)
T1  - Development of an antibody based therapy of surgical infections caused by methicillinresistant and -sensitive Staphylococcus aureus (MRSA and MSSA)
N2  - Staphylococcus aureus ist einer der häufigsten Erreger von nosokomialen Infektionen. Diese grampositiven Bakterien verursachen neben harmlosen oberflächlichen Hautinfektionen auch lebensbedrohliche Systeminfektionen. Ein großes Problem in der Therapie von S. aureus-Infektionen stellen die zunehmenden Multiresistenzen dar. Die Entwicklung neuer Antibiotika wird zukünftig wahrscheinlich nicht ausreichen, da immer wieder neue Resistenzen der Bakterien zu erwarten sind. Es besteht daher dringender Bedarf an der Entwicklung alternativer Therapieformen im Kampf gegen multiresistente Problemkeime wie S. aureus. Eine Möglichkeit besteht in der Immuntherapie, zum Beispiel durch Gewinnung von monoklonalen Antikörpern gegen geeignete Targetstrukturen von S. aureus. Ziel dieser Arbeit war es, zunächst zwei Proteine IsaA und IsaB herzustellen, um diese Proteine für Immunisierungsstudien zu nutzen. Zunächst wurde das gereinigte IsaA-Protein verwendet, um ein Kaninchen zu immunisieren. Mit den daraus gewonnenen Antikörpern wurden dann erste Tierversuche begonnen, um die Bedingungen für den therapeutischen Einatz von gegen IsaA-gerichteten Antikörpern zu ermitteln und die Wirksamkeit einer Antikörper-Behandlung zu evaluieren. Für die Herstellung der gewünschten Proteine wurden die Gensequenzen zunächst aus verschiedenen S. aureus-Stämmen mittels PCR amplifiziert und in den kommerziellen Expressionsvektor pQE30 kloniert. Die amplifizierte Gensequenz stammt aus den klinischen Stämmen 418 (IsaA) bzw. 134 (IsaB). Nach der Klonierung wurden geeignete Expressions- und Reinigungsstrategien entwickelt. Dabei wurden folgende Bedingungen als optimal für Wachstum und Überexpression herausgearbeitet: IsaA: Induktion der Überexpression mit 100 µM IPTG, 3 h Wachstum bei 37°C. IsaB: Induktion der Überexpression mit 100 µM IPTG, 4 h Wachstum bei 37°C. Es stellte sich auch heraus, dass IsaA zunächst in nur unzureichender Quantität vorhanden bzw. exprimiert worden war. Die Vermutung, dass IsaA überwiegend im Pellet in sogenannten Einschlusskörpern (inclusion bodies) eingeschlossen war, erklärte dieses Phänomen. Das Protein konnte erfolgreich aus dem Pellet isoliert werden. Die Produktion und Aufreinigung beider Proteine IsaA und IsaB unter optimierten Bedingungen ergab, dass beide Proteine nun in ausreichender Menge und Konzentration für die folgende Immunisierung und die weiteren Arbeiten vorlagen. Aus Kaninchen, die mit IsaA immunisiert wurden, konnten polyklonale Antikörper gewonnen werden, die die Grundlage für einen ersten Tierversuch mit 24 Ratten bildeten. Hierbei zeigte sich, dass die Tiere, die mit 1.000.000.000 Bakterien infiziert worden waren deutlich stärkere Infektionszeichen aufwiesen als diejenigen, die mit 100.000.000 Bakterien infiziert worden waren. Weiterhin wurde deutlich, dass die Tiere, die Serum (mit Antikörper gegen IsaA) erhalten hatten, gegenüber den Vergleichstieren mit Placebo einen deutlichen Vorteil hinsichtlich Infektionszeichen und Immunantwort hatten. Somit belegen die tierexperimentiellen Ergebnisse in dieser Arbeit erstmalig den therapeutischen Nutzen von Antikörpern gegen IsaA. IsaA ist demnach ein geeignetes Target für eine Immuntherapie gegen S. aureus.
N2  - Staphylococcus aureus is one of the most common pathogens of nosocomial infections. These grampositive bacteria not only cause harmless superficial skin infections but also life threatening systemic infections. A huge problem in therapy of S. aureus infections is the increasing rate of multiresistance. The development of new antibiotics will probably not be sufficient in the future because new resistance in bacteria is to expect. Therefore there is urgent need for alternative therapies fighting multiresistant bacteria such as S. aureus. One approach is immunotherapy, e.g. by production of monoclonal antibodies against adequate targets of S. aureus. The purpose of this paper was to produce two proteins, IsaA and IsaB, to use these for immunisation studies. First purified IsaA was used to immunise a rabbit. The extracted antibodies were used for early animal experiments to evaluate conditions for the therapeutic use and efficiency of antibodies against IsaA. For production of the wanted proteins gene sequences from various S. aureus strains were amplified by PCR and cloned into pQE30, a commercial expression vector. The amplified gene sequences come from strain 418 (IsaA) and strain 134 (IsaB). After cloning appropriate conditions for expression and purifiing were elaborated: IsaA: induction of overexpression with 100 µM IPTG, 3 h growth at 37°C. IsaB: induction of overexpression with 100 µM IPTG, 4 h growth at 37°C. First IsaA emerged to be present respectively expressed of low quantity only. The presumption that IsaA was predominantly enclosed in so called inclusion bodies explained this phenomenon. The protein could successfully isolated from the pellet. Production and purification of both proteins IsaA and IsaB under optimised conditions led to sufficient quantitiy and concentration for the immunisation following and further research. From a rabbit, immunised with IsaA, polyclonal antibodies were obtained and provided a basis for the first animal experiment with 24 rats. It showed that animals infected with 1.000.000.000 bacteria had considerably more signs of infection than those infected with 100.000.000 bacteria. It could also be shown that animals treated with serum (with antibodies against IsaA) had clear advantage regarding signs of infections and immune response compared to those animals treated with placebo. These results of the animal experiment document the therapeutic benefit of antibodies against IsaA for the first time. Therefore IsaA is an adequate target for immunotherapy against S. aureus.
KW  - MRSA
KW  - Staphylococcus aureus
KW  - Immuntherapie
KW  - Antikörper
KW  - Infektion
KW  - Target
KW  - IsaA
KW  - IsaB
KW  - IsaA
KW  - IsaB
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-56199
ER  - 
TY  - JOUR
A1  - Kayisoglu, Özge
A1  - Schlegel, Nicolas
A1  - Bartfeld, Sina
T1  - Gastrointestinal epithelial innate immunity-regionalization and organoids as new model
JF  - Journal of Molecular Medicine
N2  - The human gastrointestinal tract is in constant contact with microbial stimuli. Its barriers have to ensure co-existence with the commensal bacteria, while enabling surveillance of intruding pathogens. At the centre of the interaction lies the epithelial layer, which marks the boundaries of the body. It is equipped with a multitude of different innate immune sensors, such as Toll-like receptors, to mount inflammatory responses to microbes. Dysfunction of this intricate system results in inflammation-associated pathologies, such as inflammatory bowel disease. However, the complexity of the cellular interactions, their molecular basis and their development remains poorly understood. In recent years, stem cell-derived organoids have gained increasing attention as promising models for both development and a broad range of pathologies, including infectious diseases. In addition, organoids enable the study of epithelial innate immunity in vitro. In this review, we focus on the gastrointestinal epithelial barrier and its regional organization to discuss innate immune sensing and development.
KW  - regionalization and organoids
KW  - immunity
KW  - gastrointestinal tract
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265220
VL  - 99
IS  - 4
ER  - 
TY  - JOUR
A1  - Dischinger, Ulrich
A1  - Heckel, Tobias
A1  - Bischler, Thorsten
A1  - Hasinger, Julia
A1  - Königsrainer, Malina
A1  - Schmitt-Böhrer, Angelika
A1  - Otto, Christoph
A1  - Fassnacht, Martin
A1  - Seyfried, Florian
A1  - Hankir, Mohammed Khair
T1  - Roux-en-Y gastric bypass and caloric restriction but not gut hormone-based treatments profoundly impact the hypothalamic transcriptome in obese rats
JF  - Nutrients
N2  - Background: The hypothalamus is an important brain region for the regulation of energy balance. Roux-en-Y gastric bypass (RYGB) surgery and gut hormone-based treatments are known to reduce body weight, but their effects on hypothalamic gene expression and signaling pathways are poorly studied. Methods: Diet-induced obese male Wistar rats were randomized into the following groups: RYGB, sham operation, sham + body weight-matched (BWM) to the RYGB group, osmotic minipump delivering PYY3-36 (0.1 mg/kg/day), liraglutide s.c. (0.4 mg/kg/day), PYY3-36 + liraglutide, and saline. All groups (except BWM) were kept on a free choice of high- and low-fat diets. Four weeks after interventions, hypothalami were collected for RNA sequencing. Results: While rats in the RYGB, BWM, and PYY3-36 + liraglutide groups had comparable reductions in body weight, only RYGB and BWM treatment had a major impact on hypothalamic gene expression. In these groups, hypothalamic leptin receptor expression as well as the JAK–STAT, PI3K-Akt, and AMPK signaling pathways were upregulated. No significant changes could be detected in PYY3-36 + liraglutide-, liraglutide-, and PYY-treated groups. Conclusions: Despite causing similar body weight changes compared to RYGB and BWM, PYY3-36 + liraglutide treatment does not impact hypothalamic gene expression. Whether this striking difference is favorable or unfavorable to metabolic health in the long term requires further investigation.
KW  - obesity
KW  - Roux-en-Y gastric bypass surgery
KW  - liraglutide
KW  - PYY3-36
KW  - hypothalamic gene expression
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252392
SN  - 2072-6643
VL  - 14
IS  - 1
ER  - 
TY  - JOUR
A1  - Metzner, Valentin
A1  - Herzog, Gloria
A1  - Heckel, Tobias
A1  - Bischler, Thorsten
A1  - Hasinger, Julia
A1  - Otto, Christoph
A1  - Fassnacht, Martin
A1  - Geier, Andreas
A1  - Seyfried, Florian
A1  - Dischinger, Ulrich
T1  - Liraglutide + PYY\(_{3-36}\) combination therapy mimics effects of Roux-en-Y bypass on early NAFLD whilst lacking-behind in metabolic improvements
JF  - Journal of Clinical Medicine
N2  - Background: Treatment options for NAFLD are still limited. Bariatric surgery, such as Roux-en-Y gastric bypass (RYGB), has been shown to improve metabolic and histologic markers of NAFLD. Glucagon-like-peptide-1 (GLP-1) analogues lead to improvements in phase 2 clinical trials. We directly compared the effects of RYGB with a treatment using liraglutide and/or peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\)) in a rat model for early NAFLD. Methods: Obese male Wistar rats (high-fat diet (HFD)-induced) were randomized into the following treatment groups: RYGB, sham-operation (sham), liraglutide (0.4 mg/kg/day), PYY\(_{3-36}\) (0.1 mg/kg/day), liraglutide+PYY\(_{3-36}\), and saline. After an observation period of 4 weeks, liver samples were histologically evaluated, ELISAs and RNA sequencing + RT-qPCRs were performed. Results: RYGB and liraglutide+PYY\(_{3-36}\) induced a similar body weight loss and, compared to sham/saline, marked histological improvements with significantly less steatosis. However, only RYGB induced significant metabolic improvements (e.g., adiponectin/leptin ratio 18.8 ± 11.8 vs. 2.4 ± 1.2 in liraglutide+PYY\(_{3-36}\)- or 1.4 ± 0.9 in sham-treated rats). Furthermore, RNA sequencing revealed a high number of differentially regulated genes in RYGB treated animals only. Conclusions: The combination therapy of liraglutide+PYY\(_{3-36}\) partly mimics the positive effects of RYGB on weight reduction and on hepatic steatosis, while its effects on metabolic function lack behind RYGB.
KW  - liraglutide
KW  - GLP-1
KW  - peptide tyrosine tyrosine (PYY)
KW  - peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\))
KW  - RYGB
KW  - gastric bypass
KW  - obesity
KW  - NASH
KW  - NAFLD
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-255244
SN  - 2077-0383
VL  - 11
IS  - 3
ER  - 
TY  - JOUR
A1  - Wallaschek, Nina
A1  - Reuter, Saskia
A1  - Silkenat, Sabrina
A1  - Wolf, Katharina
A1  - Niklas, Carolin
A1  - Özge, Kayisoglu
A1  - Aguilar, Carmen
A1  - Wiegering, Armin
A1  - Germer, Christoph-Thomas
A1  - Kircher, Stefan
A1  - Rosenwald, Andreas
A1  - Shannon-Lowe, Claire
A1  - Bartfeld, Sina
T1  - Ephrin receptor A2, the epithelial receptor for Epstein-Barr virus entry, is not available for efficient infection in human gastric organoids
JF  - PLoS Pathogens
N2  - Epstein-Barr virus (EBV) is best known for infection of B cells, in which it usually establishes an asymptomatic lifelong infection, but is also associated with the development of multiple B cell lymphomas. EBV also infects epithelial cells and is associated with all cases of undifferentiated nasopharyngeal carcinoma (NPC). EBV is etiologically linked with at least 8% of gastric cancer (EBVaGC) that comprises a genetically and epigenetically distinct subset of GC. Although we have a very good understanding of B cell entry and lymphomagenesis, the sequence of events leading to EBVaGC remains poorly understood. Recently, ephrin receptor A2 (EPHA2) was proposed as the epithelial cell receptor on human cancer cell lines. Although we confirm some of these results, we demonstrate that EBV does not infect healthy adult stem cell-derived gastric organoids. In matched pairs of normal and cancer-derived organoids from the same patient, EBV only reproducibly infected the cancer organoids. While there was no clear pattern of differential expression between normal and cancer organoids for EPHA2 at the RNA and protein level, the subcellular location of the protein differed markedly. Confocal microscopy showed EPHA2 localization at the cell-cell junctions in primary cells, but not in cancer cell lines. Furthermore, histologic analysis of patient tissue revealed the absence of EBV in healthy epithelium and presence of EBV in epithelial cells from inflamed tissue. These data suggest that the EPHA2 receptor is not accessible to EBV on healthy gastric epithelial cells with intact cell-cell contacts, but either this or another, yet to be identified receptor may become accessible following cellular changes induced by inflammation or transformation, rendering changes in the cellular architecture an essential prerequisite to EBV infection.
KW  - Organoids
KW  - ephitelial cells
KW  - gastrointestinal infections
KW  - cancers and neoplasms
KW  - Epstein-Barr virus
KW  - flow cytometry
KW  - epithelium
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259206
VL  - 17
IS  - 2
ER  -