Investigation of the Phosphorylation of theC-terminal domains of the cardiac MyosinBinding Protein C by the 5-AMP-activatedProtein Kinase

The existence of MyBP-C in striated muscle has been known for over 35 years and about 150 mutations in the gene encoding cMyBP-C have been found to be a common cause of hypertrophic cardiomyopathy. Despite this, the structure and function of MyBP-C remains less well understood than most other sarcomeric proteins, with roles in both regulation of contraction and thick filament formation/stability being proposed. In addition to the well known interactions of MyBP-C with other proteins of the sarcomeric apparatus (LMM, titin, actin) and with PKA, CaMKK and PKC at the N-terminal end of the protein, the aim of this study was to investigate interactions of MyBP-Cs C-terminus with the 5-AMP-activated protein kinase. This enzyme came in the focus of research during the last decade as it appears to function in a plethora of cell processes. Further, it has been elucidated that mutations in PRKAG2, encoding for the γ2 subunit of AMPK, causes left ventricular hypertrophy associated with conduction system diseases (e.g. Wolf-Parkinson-White syndrome). Important questions that have to be answered for a better understanding of this issue are, beside others, the identification of the full repertoire of cardiac protein targets. My project aimed at identifying the site or sites of AMPK phosphorylation within the C-terminal three domains of cMyBP-C as suggested by earlier yeast-two-hybridscreen data and biochemical work. The latter hinted that the C8 domain was most likely the target, and it is this fragment that my work began with. Having optimised the expression and purification of recombinant wild type MyBP-C C8 domain and a number of mutated C8 domains as discussed in Chapter 3, it was possible to disprove the hypothesis of phosphorylatable residues being in this domain. In contrast, it was revealed that a phosphorylatable serine moiety was present in the N-terminal leader of the recombinant protein, encoded by the vector pET-28a. This serine lies in the thrombin recognition sequence itself and its phosphorylation inhibits cleavage. However, it was shown in vitro that a phosphorylatable serine residue is located in the C10 domain of the protein and this further confirms the association of the C8-C10 fragment of MyBP-C with AMPK, first observed in the yeast two-hybrid assay. The hypotheses that arise from these results will be discussed in this chapter. Additionally, I showed that the N-terminal domains of cMyBP-C (C0-C2), which contain the well characterized PKA and CaMII sites, are not a good substrate for AMPK in vitro

Neuronale Signalwege in der Entstehung und Progression gastrointestinaler Tumore unter besonderer Berücksichtigung des duktalen Pankreaskarzinoms

Die Entitäten des Pankreaskarzinoms und des Magenkarzinoms sind häufige Tumorentitäten, bei denen die chirurgische Resektion, wenn der Primärtumor respektabel ist, die zentrale Rolle spielt. Die Chirurgie muss dann in ein multimodales Behandlungskonzept eingebunden werden. Trotz der chirurgischen Resektion besteht allerdings in vielen Fällen ein hohes Rezidiv- und Metastasierungsrisiko. Hinzu kommt, dass eine Heilung in der metastasierten Situation praktisch unmöglich ist. Dementsprechend liegt hier ein erheblicher Forschungsbedarf sowohl bei adjuvanten und palliativen Therapieverfahren als auch im besseren Verständnis der Biologie dieser Erkrankungen vor, um weitere potentielle therapeutische Zielstrukturen zu identifizieren und entsprechende Behandlungsstrategien zu entwickeln. Die hier vorliegende kumulative Habilitationsschrift beschäftigt sich mit dem Einfluss des autonomen Nervensystems auf die Initiierung und Progression des Pankreas und Magenkarzinoms. Die Schrift setzt sich aus Arbeiten zusammen, bei denen zum einen die Rolle des autonomen Nervensystems (Sympathikus und Parasympathikus) in der Initiierung und Progression des PDACs und zum anderen die Rolle des N. vagus in der Entwicklung des Magenkarzinoms untersucht wurden. Hierzu wurden aktuellste in vitro Methoden verwendet und teilweise neue GEMMs für in vivo Untersuchungen entwickelt. Im Rahmen der Arbeiten wurden einige dieser GEMMs neu generiert. Aufgeführt werden hier die vier wichtigsten Arbeiten des Autors aus dem Bereich der Tumorneurobiologie

Neuronale Signalwege in der Entstehung und Progression gastrointestinaler Tumore unter besonderer Berücksichtigung des duktalen Pankreaskarzinoms

Die Entitäten des Pankreaskarzinoms und des Magenkarzinoms sind häufige Tumorentitäten, bei denen die chirurgische Resektion, wenn der Primärtumor respektabel ist, die zentrale Rolle spielt. Die Chirurgie muss dann in ein multimodales Behandlungskonzept eingebunden werden. Trotz der chirurgischen Resektion besteht allerdings in vielen Fällen ein hohes Rezidiv- und Metastasierungsrisiko. Hinzu kommt, dass eine Heilung in der metastasierten Situation praktisch unmöglich ist. Dementsprechend liegt hier ein erheblicher Forschungsbedarf sowohl bei adjuvanten und palliativen Therapieverfahren als auch im besseren Verständnis der Biologie dieser Erkrankungen vor, um weitere potentielle therapeutische Zielstrukturen zu identifizieren und entsprechende Behandlungsstrategien zu entwickeln. Die hier vorliegende kumulative Habilitationsschrift beschäftigt sich mit dem Einfluss des autonomen Nervensystems auf die Initiierung und Progression des Pankreas und Magenkarzinoms. Die Schrift setzt sich aus Arbeiten zusammen, bei denen zum einen die Rolle des autonomen Nervensystems (Sympathikus und Parasympathikus) in der Initiierung und Progression des PDACs und zum anderen die Rolle des N. vagus in der Entwicklung des Magenkarzinoms untersucht wurden. Hierzu wurden aktuellste in vitro Methoden verwendet und teilweise neue GEMMs für in vivo Untersuchungen entwickelt. Im Rahmen der Arbeiten wurden einige dieser GEMMs neu generiert. Aufgeführt werden hier die vier wichtigsten Arbeiten des Autors aus dem Bereich der Tumorneurobiologie

On Qualitative Route Descriptions: Representation and Computational Complexity

The generation of route descriptions is a fundamental task of navigation systems. A particular problem in this context is to identify routes that can easily be described and processed by users. In this work, we present a framework for representing route

Exercise as a Potential Intervention to Modulate Cancer Outcomes in Children and Adults?

Exercise is recommended for the healthy population as it increases fitness and prevents diseases. Moreover, exercise is also applied as an adjunct therapy for patients with various chronic diseases including cancer. Childhood cancer is a rare, heterogeneous disease that differs from adult cancer. Improved therapeutic strategies have increased childhood cancer survival rates to above 80% in developed countries. Although this is higher than the average adult cancer survival rate of about 50%, therapy results often in substantial long-term side effects in childhood cancer survivors. Exercise in adult cancer patients has many beneficial effects and may slow down tumor progression and improve survival in some cancer types, suggesting that exercise may influence cancer cell behavior. In contrast to adults, there is not much data on general effects of exercise in children. Whilst it seems possible that exercise might delay cancer progression or improve survival in children as well, there is no reliable data yet to support this hypothesis. Depending on the type of cancer, animal studies of adult cancer types show that the exercise-induced increase of the catecholamines epinephrine and norepinephrine, have suppressive as well as promoting effects on cancer cells. The diverse effects of exercise in adult cancer patients require investigating whether these results can be achieved in children with cancer

Monitoring of multiple fabrication parameters of electrospun polymer fibers using mueller matrix analysis

Electrospun polymer fiber mats feature versatile applications in tissue engineering, drug delivery, water treatment and chemical processes. The orientation of fibers within these mats is a crucial factor that significantly influences their properties and performance. However, the analysis of fiber samples using scanning electron microscopy (SEM) has limitations such as time consumption, fixed assembly, and restricted field of vision. Therefore, a fast and reliable method for qualitative measurements of fiber orientation is required. Mueller matrix polarimetry, a well-established method for measuring orientation of chemical and biological species, was employed in this case. We investigated the effect of four important parameters of the electrospinning process, namely collector speed, applied voltage, needle-to-collector distance, and solution concentration, on fiber orientation using Mueller matrix polarimetry thus extending the range of parameters analyzed. Measurements were performed using two extreme values and a central optimized value for each fabrication parameter. Changes in matrix values were observed for each fabrication parameter, and their correlation with fiber orientation was analyzed based on the Lu-Chipman decomposition. The results were compared with SEM images, which served as the ground truth, and showed overall good agreement. In the future, the analysis of electrospun polymer fibers can be done by using Mueller matrix polarimetry as alternative to current technology and fabrication parameters, including solution concentration for the first time in this context and the production can quickly be adjusted based on the outcome of the measurements

Investigation of the molecular switching process between spin crossover states of triazole complexes as basis for optical sensing applications

With the advent of the first laser sources and suitable detectors, optical sensor applications immediately also came into focus. During the last decades, a huge variety of optical sensor concepts were developed, yet the forecast for the future application potential appears even larger. In this context, the development of new sensor probes at different scales down to the atomic or molecular level open new avenues for research and development. We investigated an iron based triazole molecular spin-crossover complex changing its absorption characteristics significantly by varying environmental parameters such as humidity, temperature, magnetic or electric field, respectively, with respect to its suitability for a new class of versatile molecular sensor probes. Hereby, besides the investigation of synthesized pure bulk material using different analyzing methods, we also studied amorphous micro particles which were applied in or onto optical waveguide structures. We found that significant changes of the reflection spectra can also be obtained after combining the particles with different types of optical waveguides.The obtained results demonstrate the suitability of the material complex for a broad field of future sensor applications

Thin films with implemented molecular switches for the application in polymer-based optical waveguides

Complexes like iron (II)-triazoles exhibit spin crossover behavior at ambient temperature and are often considered for possible application. In previous studies, we implemented complexes of this type into polymer nanofibers and first polymer-based optical waveguide sensor systems. In our current study, we synthesized complexes of this type, implemented them into polymers and obtained composites through drop casting and doctor blading. We present that a certain combination of polymer and complex can lead to composites with high potential for optical devices. For this purpose, we used two different complexes [Fe(atrz)3](2ns)2 and [Fe(atrz)3]Cl1.5(BF4)0.5 with different polymers for each composite. We show through transmission measurements and UV/VIS spectroscopy that the optical properties of these composite materials can reversibly change due to the spin crossover effect

The Analgesic Effect of the Mitochondria-Targeted Antioxidant SkQ1 in Pancreatic Inflammation

Background. Chronic pancreatitis is one of the main risk factors for pancreatic cancer. In acute and chronic pancreatitis, oxidative stress is thought to play a key role. In this respect, the recently described mitochondria-targeted antioxidant SkQ1 effectively scavenges reactive oxygen species at nanomolar concentrations. Therefore, we aimed to characterize the influence of SkQ1 on tissue injury and pain in acute and chronic pancreatitis. Methods. Both acute and chronic pancreatitis were induced in C57BL/6 mice by intraperitoneal cerulein injections and treatment with SkQ1 was carried out by peroral applications. Hyperalgesia was assessed by behavioral observation and measurement of abdominal mechanical sensitivity. Blood serum and pancreatic tissue were harvested for analysis of lipase and histology. Results. SkQ1 did not influence pain, serological, or histological parameters of tissue injury in acute pancreatitis. In chronic pancreatitis, a highly significant reduction of pain-related behavior (p < 0.0001) was evident, but histological grading revealed increased tissue injury in SkQ1-treated animals (p = 0.03). Conclusion. After SkQ1 treatment, tissue injury is not ameliorated in acute pancreatitis and increased in chronic pancreatitis. However, we show an analgesic effect in chronic pancreatitis. Further studies will need to elucidate the risks and benefits of mitochondria-targeted antioxidants as an analgesic

Infections after kidney transplantation: A comparison of mTOR‐Is and CNIs as basic immunosuppressants. A systematic review and meta‐analysis

Background Side effects of the immunosuppressive therapy after solid organ transplantation are well known. Recently, significant benefits were shown for mTOR‐Is with respect to certain viral infections in comparison with CNIs. However, reported total incidences of infections under mTOR‐Is vs CNIs are usually not different. This raises the question to additional differences between these immunosuppressants regarding development and incidence of infections. Methods The current literature was searched for prospective randomized controlled trials in renal transplantation. There were 954 trials screened of which 19 could be included (9861 pts.). The 1‐year incidence of infections, patient and graft survival were assessed in meta‐analyses. Results Meta‐analysis on 1‐year incidence of infections showed a significant benefit of an mTOR‐I based therapy when combined with a CNI vs CNI‐based therapy alone (OR 0.76). There was no difference between mTOR‐I w/o CNI and CNI therapy (OR 0.97). For pneumonia, a significant disadvantage was seen only for mTOR‐I monotherapy compared to CNI's (OR 2.09). The incidence of CMV infections was significantly reduced under mTOR‐I therapy (combination with CNI: OR 0.30; mTOR w/o CNI: OR: 0.46). There was no significant difference between mTOR‐I and CNI therapy with respect to patient survival (mTOR‐I w/o CNI vs CNI: OR 1.22; mTOR‐I with CNI vs CNI: OR 0.86). Graft survival was negatively affected by mTOR‐I monotherapy (OR 1.52) but not when combined with a CNI (OR 0.97). Conclusion Following renal transplantation the incidence of infections is lower when mTOR‐Is are combined with a CNI compared to a standard CNI therapy. Pneumonia occurs more often under mTOR‐I w/o CNI