@article{WorkuStichDaugschiesetal.2015, author = {Worku, Netsanet and Stich, August and Daugschies, Arwid and Wenzel, Iris and Kurz, Randy and Thieme, Rene and Kurz, Susanne and Birkenmeier, Gerd}, title = {Ethyl Pyruvate Emerges as a Safe and Fast Acting Agent against Trypanosoma brucei by Targeting Pyruvate Kinase Activity}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {9}, doi = {10.1371/journal.pone.0137353}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150002}, pages = {e0137353}, year = {2015}, abstract = {Background Human African Trypanosomiasis (HAT) also called sleeping sickness is an infectious disease in humans caused by an extracellular protozoan parasite. The disease, if left untreated, results in 100\% mortality. Currently available drugs are full of severe drawbacks and fail to escape the fast development of trypanosoma resistance. Due to similarities in cell metabolism between cancerous tumors and trypanosoma cells, some of the current registered drugs against HAT have also been tested in cancer chemotherapy. Here we demonstrate for the first time that the simple ester, ethyl pyruvate, comprises such properties. Results The current study covers the efficacy and corresponding target evaluation of ethyl pyruvate on T. brucei cell lines using a combination of biochemical techniques including cell proliferation assays, enzyme kinetics, phasecontrast microscopic video imaging and ex vivo toxicity tests. We have shown that ethyl pyruvate effectively kills trypanosomes most probably by net ATP depletion through inhibition of pyruvate kinase (Ki = 3.0\(\pm\)0.29 mM). The potential of ethyl pyruvate as a trypanocidal compound is also strengthened by its fast acting property, killing cells within three hours post exposure. This has been demonstrated using video imaging of live cells as well as concentration and time dependency experiments. Most importantly, ethyl pyruvate produces minimal side effects in human red cells and is known to easily cross the blood-brain-barrier. This makes it a promising candidate for effective treatment of the two clinical stages of sleeping sickness. Trypanosome drug-resistance tests indicate irreversible cell death and a low incidence of resistance development under experimental conditions. Conclusion Our results present ethyl pyruvate as a safe and fast acting trypanocidal compound and show that it inhibits the enzyme pyruvate kinase. Competitive inhibition of this enzyme was found to cause ATP depletion and cell death. Due to its ability to easily cross the blood-brain-barrier, ethyl pyruvate could be considered as new candidate agent to treat the hemo-lymphatic as well as neurological stages of sleeping sickness.}, language = {en} } @article{WeilandBeezWestermaieretal.2021, author = {Weiland, Judith and Beez, Alexandra and Westermaier, Thomas and Kunze, Ekkehard and Sir{\´e}n, Anna-Leena and Lilla, Nadine}, title = {Neuroprotective strategies in aneurysmal subarachnoid hemorrhage (aSAH)}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {11}, issn = {1422-0067}, doi = {10.3390/ijms22115442}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260755}, year = {2021}, abstract = {Aneurysmal subarachnoid hemorrhage (aSAH) remains a disease with high mortality and morbidity. Since treating vasospasm has not inevitably led to an improvement in outcome, the actual emphasis is on finding neuroprotective therapies in the early phase following aSAH to prevent secondary brain injury in the later phase of disease. Within the early phase, neuroinflammation, thromboinflammation, disturbances in brain metabolism and early neuroprotective therapies directed against delayed cerebral ischemia (DCI) came into focus. Herein, the role of neuroinflammation, thromboinflammation and metabolism in aSAH is depicted. Potential neuroprotective strategies regarding neuroinflammation target microglia activation, metalloproteases, autophagy and the pathway via Toll-like receptor 4 (TLR4), high mobility group box 1 (HMGB1), NF-κB and finally the release of cytokines like TNFα or IL-1. Following the link to thromboinflammation, potential neuroprotective therapies try to target microthrombus formation, platelets and platelet receptors as well as clot clearance and immune cell infiltration. Potential neuroprotective strategies regarding metabolism try to re-balance the mismatch of energy need and supply following aSAH, for example, in restoring fuel to the TCA cycle or bypassing distinct energy pathways. Overall, this review addresses current neuroprotective strategies in aSAH, hopefully leading to future translational therapy options to prevent secondary brain injury.}, language = {en} } @article{TrivanovicVolkmannStoeckletal.2023, author = {Trivanovic, Drenka and Volkmann, Noah and Stoeckl, Magdalena and Tertel, Tobias and Rudert, Maximilian and Giebel, Bernd and Herrmann, Marietta}, title = {Enhancement of immunosuppressive activity of mesenchymal stromal cells by platelet-derived factors is accompanied by apoptotic priming}, series = {Stem Cell Reviews and Reports}, volume = {19}, journal = {Stem Cell Reviews and Reports}, number = {3}, doi = {10.1007/s12015-022-10471-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324669}, pages = {713-733}, year = {2023}, abstract = {The pro-inflammatory phase of bone healing, initiated by platelet activation and eventually hematoma formation, impacts bone marrow mesenchymal stromal cells (MSCs) in unknown ways. Here, we created platelet-rich plasma (PRP) hydrogels to study how platelet-derived factors modulate functional properties of encapsulated MSCs in comparison to a non-inflammatory fibrin (FBR) hydrogel environment. MSCs were isolated from human bone marrow, while PRP was collected from pooled apheresis thrombocyte concentrates and used for hydrogel preparation. After their encapsulation in hydrogels for 72 h, retrieved MSCs were analyzed for immunomodulatory activities, apoptosis, stem cell properties, senescence, CD9\(^+\), CD63\(^+\) and CD81\(^+\) extracellular vesicle (EV) release, and metabolism-related changes. PRP-hydrogels stimulated immunosuppressive functions of MSCs, along with their upregulated susceptibility to cell death in communication with PBMCs and augmented caspase 3/7 activity. We found impaired clonal growth and cell cycle progression, and more pronounced β-galactosidase activity as well as accumulation of LC3-II-positive vacuoles in PRP-MSCs. Stimuli derived from PRP-hydrogels upregulated AKT and reduced mTOR phosphorylation in MSCs, which suggests an initiation of survival-related processes. Our results showed that PRP-hydrogels might represent a metabolically stressful environment, inducing acidification of MSCs, reducing polarization of the mitochondrial membrane and increasing lipid accumulation. These features were not detected in FBR-MSCs, which showed reduced CD63\(^+\) and CD81\(^+\) EV production and maintained clonogenicity. Our data revealed that PRP-derived hematoma components cause metabolic adaptation of MSCs followed by increased immune regulatory functions. For the first time, we showed that PRP stimuli represent a survival challenge and "apoptotic priming" that are detrimental for stem cell-like growth of MSCs and important for their therapeutic consideration.}, language = {en} } @article{TomeNaegeleAdamoetal.2014, author = {Tome, Filipa and N{\"a}gele, Thomas and Adamo, Mattia and Garg, Abhroop and Marco-Ilorca, Carles and Nukarinen, Ella and Pedrotti, Lorenzo and Peviani, Alessia and Simeunovic, Andrea and Tatkiewicz, Anna and Tomar, Monika and Gamm, Magdalena}, title = {The low energy signaling network}, series = {Frontiers in Plant Science}, volume = {5}, journal = {Frontiers in Plant Science}, number = {353}, issn = {1664-462X}, doi = {10.3389/fpls.2014.00353}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115813}, year = {2014}, abstract = {Stress impacts negatively on plant growth and crop productivity, causing extensive losses to agricultural production worldwide. Throughout their life, plants are often confronted with multiple types of stress that affect overall cellular energy status and activate energy-saving responses. The resulting low energy syndrome (LES) includes transcriptional, translational, and metabolic reprogramming and is essential for stress adaptation. The conserved kinases sucrose-non-fermenting-1-related protein kinase-1 (SnRK1) and target of rapamycin (TOR) play central roles in the regulation of LES in response to stress conditions, affecting cellular processes and leading to growth arrest and metabolic reprogramming. We review the current understanding of how TOR and SnRK1 are involved in regulating the response of plants to low energy conditions. The central role in the regulation of cellular processes, the reprogramming of metabolism, and the phenotypic consequences of these two kinases will be discussed in light of current knowledge and potential future developments.}, language = {en} } @article{SchmitzKodererElMeseryetal.2021, author = {Schmitz, Werner and Koderer, Corinna and El-Mesery, Mohamed and Gobik, Sebastian and Sampers, Rene and Straub, Anton and K{\"u}bler, Alexander Christian and Seher, Axel}, title = {Metabolic fingerprinting of murine L929 fibroblasts as a cell-based tumour suppressor model system for methionine restriction}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {6}, issn = {1422-0067}, doi = {10.3390/ijms22063039}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259198}, year = {2021}, abstract = {Since Otto Warburg reported in 1924 that cancer cells address their increased energy requirement through a massive intake of glucose, the cellular energy level has offered a therapeutic anticancer strategy. Methionine restriction (MetR) is one of the most effective approaches for inducing low-energy metabolism (LEM) due to the central position in metabolism of this amino acid. However, no simple in vitro system for the rapid analysis of MetR is currently available, and this study establishes the murine cell line L929 as such a model system. L929 cells react rapidly and efficiently to MetR, and the analysis of more than 150 different metabolites belonging to different classes (amino acids, urea and tricarboxylic acid cycle (TCA) cycles, carbohydrates, etc.) by liquid chromatography/mass spectrometry (LC/MS) defines a metabolic fingerprint and enables the identification of specific metabolites representing normal or MetR conditions. The system facilitates the rapid and efficient testing of potential cancer therapeutic metabolic targets. To date, MS studies of MetR have been performed using organisms and yeast, and the current LC/MS analysis of the intra- and extracellular metabolites in the murine cell line L929 over a period of 5 days thus provides new insights into the effects of MetR at the cellular metabolic level.}, language = {en} } @article{SchererFleishmanJonesetal.2021, author = {Scherer, Marc and Fleishman, Sarel J. and Jones, Patrik R. and Dandekar, Thomas and Bencurova, Elena}, title = {Computational Enzyme Engineering Pipelines for Optimized Production of Renewable Chemicals}, series = {Frontiers in Bioengineering and Biotechnology}, volume = {9}, journal = {Frontiers in Bioengineering and Biotechnology}, issn = {2296-4185}, doi = {10.3389/fbioe.2021.673005}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240598}, year = {2021}, abstract = {To enable a sustainable supply of chemicals, novel biotechnological solutions are required that replace the reliance on fossil resources. One potential solution is to utilize tailored biosynthetic modules for the metabolic conversion of CO2 or organic waste to chemicals and fuel by microorganisms. Currently, it is challenging to commercialize biotechnological processes for renewable chemical biomanufacturing because of a lack of highly active and specific biocatalysts. As experimental methods to engineer biocatalysts are time- and cost-intensive, it is important to establish efficient and reliable computational tools that can speed up the identification or optimization of selective, highly active, and stable enzyme variants for utilization in the biotechnological industry. Here, we review and suggest combinations of effective state-of-the-art software and online tools available for computational enzyme engineering pipelines to optimize metabolic pathways for the biosynthesis of renewable chemicals. Using examples relevant for biotechnology, we explain the underlying principles of enzyme engineering and design and illuminate future directions for automated optimization of biocatalysts for the assembly of synthetic metabolic pathways.}, language = {en} } @article{SchanbacherHermannsLorenzetal.2023, author = {Schanbacher, Constanze and Hermanns, Heike M. and Lorenz, Kristina and Wajant, Harald and Lang, Isabell}, title = {Complement 1q/tumor necrosis factor-related proteins (CTRPs): structure, receptors and signaling}, series = {Biomedicines}, volume = {11}, journal = {Biomedicines}, number = {2}, issn = {2227-9059}, doi = {10.3390/biomedicines11020559}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304136}, year = {2023}, abstract = {Adiponectin and the other 15 members of the complement 1q (C1q)/tumor necrosis factor (TNF)-related protein (CTRP) family are secreted proteins composed of an N-terminal variable domain followed by a stalk region and a characteristic C-terminal trimerizing globular C1q (gC1q) domain originally identified in the subunits of the complement protein C1q. We performed a basic PubMed literature search for articles mentioning the various CTRPs or their receptors in the abstract or title. In this narrative review, we briefly summarize the biology of CTRPs and focus then on the structure, receptors and major signaling pathways of CTRPs. Analyses of CTRP knockout mice and CTRP transgenic mice gave overwhelming evidence for the relevance of the anti-inflammatory and insulin-sensitizing effects of CTRPs in autoimmune diseases, obesity, atherosclerosis and cardiac dysfunction. CTRPs form homo- and heterotypic trimers and oligomers which can have different activities. The receptors of some CTRPs are unknown and some receptors are redundantly targeted by several CTRPs. The way in which CTRPs activate their receptors to trigger downstream signaling pathways is largely unknown. CTRPs and their receptors are considered as promising therapeutic targets but their translational usage is still hampered by the limited knowledge of CTRP redundancy and CTRP signal transduction.}, language = {en} } @article{SchadtIsraelBeezetal.2023, author = {Schadt, Fabian and Israel, Ina and Beez, Alexandra and Alushi, Kastriot and Weiland, Judith and Ernestus, Ralf-Ingo and Westermaier, Thomas and Samnick, Samuel and Lilla, Nadine}, title = {Analysis of cerebral glucose metabolism following experimental subarachnoid hemorrhage over 7 days}, series = {Scientific Reports}, volume = {13}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-022-26183-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300725}, year = {2023}, abstract = {Little is known about changes in brain metabolism following SAH, possibly leading towards secondary brain damage. Despite sustained progress in the last decade, analysis of in vivo acquired data still remains challenging. The present interdisciplinary study uses a semi-automated data analysis tool analyzing imaging data independently from the administrated radiotracer. The uptake of 2-[18F]Fluoro-2-deoxy-glucose ([\(^{18}\)F]FDG) was evaluated in different brain regions in 14 male Sprague-Dawley rats, randomized into two groups: (1) SAH induced by the endovascular filament model and (2) sham operated controls. Serial [\(^{18}\)F]FDG-PET measurements were carried out. Quantitative image analysis was performed by uptake ratio using a self-developed MRI-template based data analysis tool. SAH animals showed significantly higher [\(^{18}\)F]FDG accumulation in gray matter, neocortex and olfactory system as compared to animals of the sham group, while white matter and basal forebrain region showed significant reduced tracer accumulation in SAH animals. All significant metabolic changes were visualized from 3 h, over 24 h (day 1), day 4 and day 7 following SAH/sham operation. This [\(^{18}\)F]FDG-PET study provides important insights into glucose metabolism alterations following SAH—for the first time in different brain regions and up to day 7 during course of disease.}, language = {en} } @article{RiegerBaehrMaureretal.2014, author = {Rieger, Johannes and B{\"a}hr, Oliver and Maurer, Gabriele D. and Hattingen, Elke and Franz, Kea and Brucker, Daniel and Walenta, Stefan and K{\"a}mmerer, Ulrike and Coy, Johannes F. and Weller, Michael and Steinbach, Joachim P.}, title = {ERGO: A pilot study of ketogenic diet in recurrent glioblastoma}, series = {International Journal of Oncology}, volume = {44}, journal = {International Journal of Oncology}, number = {6}, doi = {10.3892/ijo.2014.2382}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121170}, pages = {1843-52}, year = {2014}, abstract = {Limiting dietary carbohydrates inhibits glioma growth in preclinical models. Therefore, the ERGO trial (NCT00575146) examined feasibility of a ketogenic diet in 20 patients with recurrent glioblastoma. Patients were put on a low-carbohydrate, ketogenic diet containing plant oils. Feasibility was the primary endpoint, secondary endpoints included the percentage of patients reaching urinary ketosis, progression-free survival (PFS) and overall survival. The effects of a ketogenic diet alone or in combination with bevacizumab was also explored in an orthotopic U87MG glioblastoma model in nude mice. Three patients (15\%) discontinued the diet for poor tolerability. No serious adverse events attributed to the diet were observed. Urine ketosis was achieved at least once in 12 of 13 (92\%) evaluable patients. One patient achieved a minor response and two patients had stable disease after 6 weeks. Median PFS of all patients was 5 (range, 3-13) weeks, median survival from enrollment was 32 weeks. The trial allowed to continue the diet beyond progression. Six of 7 (86\%) patients treated with bevacizumab and diet experienced an objective response, and median PFS on bevacizumab was 20.1 (range, 12-124) weeks, for a PFS at 6 months of 43\%. In the mouse glioma model, ketogenic diet alone had no effect on median survival, but increased that of bevacizumab-treated mice from 52 to 58 days (p<0.05). In conclusion, a ketogenic diet is feasible and safe but probably has no significant clinical activity when used as single agent in recurrent glioma. Further clinical trials are necessary to clarify whether calorie restriction or the combination with other therapeutic modalities, such as radiotherapy or anti-angiogenic treatments, could enhance the efficacy of the ketogenic diet.}, language = {en} } @article{PetritschKoestlerGassenmaieretal.2016, author = {Petritsch, Bernhard and K{\"o}stler, Herbert and Gassenmaier, Tobias and Kunz, Andreas S and Bley, Thorsten A and Horn, Michael}, title = {An investigation into potential gender-specific differences in myocardial triglyceride content assessed by \(^{1}\)H-Magnetic Resonance Spectroscopy at 3Tesla}, series = {Journal of International Medical Research}, volume = {44}, journal = {Journal of International Medical Research}, number = {3}, doi = {10.1177/0300060515603884}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168808}, pages = {585-591}, year = {2016}, abstract = {Objective: Over the past decade, myocardial triglyceride content has become an accepted biomarker for chronic metabolic and cardiac disease. The purpose of this study was to use proton (hydrogen 1)-magnetic resonance spectroscopy (\(^{1}\)H-MRS) at 3Tesla (3 T) field strength to assess potential gender-related differences in myocardial triglyceride content in healthy individuals. Methods: Cardiac MR imaging was performed to enable accurate voxel placement and obtain functional and morphological information. Double triggered (i.e., ECG and respiratory motion gating) \(^{1}\)H-MRS was used to quantify myocardial triglyceride levels for each gender. Two-sample t-test and Mann-Whitney U-test were used for statistical analyses. Results: In total, 40 healthy volunteers (22 male, 18 female; aged >18 years and age matched) were included in the study. Median myocardial triglyceride content was 0.28\% (interquartile range [IQR] 0.17-0.42\%) in male and 0.24\% (IQR 0.14-0.45\%) in female participants, and no statistically significant difference was observed between the genders. Furthermore, no gender-specific difference in ejection fraction was observed, although on average, male participants presented with a higher mean ± SD left ventricular mass (136.3 ± 25.2 g) than female participants (103.9 ± 16.1 g). Conclusions: The study showed that \(^{1}\)H-MRS is a capable, noninvasive tool for acquisition of myocardial triglyceride metabolites. Myocardial triglyceride concentration was shown to be unrelated to gender in this group of healthy volunteers.}, language = {en} } @article{OhlebuschBorstFrankenbachetal.2020, author = {Ohlebusch, Barbara and Borst, Angela and Frankenbach, Tina and Klopocki, Eva and Jakob, Franz and Liedtke, Daniel and Graser, Stephanie}, title = {Investigation of alpl expression and Tnap-activity in zebrafish implies conserved functions during skeletal and neuronal development}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, doi = {10.1038/s41598-020-70152-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230024}, year = {2020}, abstract = {Hypophosphatasia (HPP) is a rare genetic disease with diverse symptoms and a heterogeneous severity of onset with underlying mutations in the ALPL gene encoding the ectoenzyme Tissue-nonspecific alkaline phosphatase (TNAP). Considering the establishment of zebrafish (Danio rerio) as a new model organism for HPP, the aim of the study was the spatial and temporal analysis of alpl expression in embryos and adult brains. Additionally, we determined functional consequences of Tnap inhibition on neural and skeletal development in zebrafish. We show that expression of alpl is present during embryonic stages and in adult neuronal tissues. Analyses of enzyme function reveal zones of pronounced Tnap-activity within the telencephalon and the mesencephalon. Treatment of zebrafish embryos with chemical Tnap inhibitors followed by axonal and cartilage/mineralized tissue staining imply functional consequences of Tnap deficiency on neuronal and skeletal development. Based on the results from neuronal and skeletal tissue analyses, which demonstrate an evolutionary conserved role of this enzyme, we consider zebrafish as a promising species for modeling HPP in order to discover new potential therapy strategies in the long-term.}, language = {en} } @article{NwoghaAbtewRaveendranetal.2023, author = {Nwogha, Jeremiah S. and Abtew, Wosene G. and Raveendran, Muthurajan and Oselebe, Happiness O. and Obidiegwu, Jude E. and Chilaka, Cynthia A. and Amirtham, Damodarasamy D.}, title = {Role of non-structural sugar metabolism in regulating tuber dormancy in white yam (Dioscorea rotundata)}, series = {Agriculture}, volume = {13}, journal = {Agriculture}, number = {2}, issn = {2077-0472}, doi = {10.3390/agriculture13020343}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304486}, year = {2023}, abstract = {Changes in sugar composition occur continuously in plant tissues at different developmental stages. Tuber dormancy induction, stability, and breaking are very critical developmental transitions in yam crop production. Prolonged tuber dormancy after physiological maturity has constituted a great challenge in yam genetic improvement and productivity. In the present study, biochemical profiling of non-structural sugar in yam tubers during dormancy was performed to determine the role of non-structural sugar in yam tuber dormancy regulation. Two genotypes of the white yam species, one local genotype (Obiaoturugo) and one improved genotype (TDr1100873), were used for this study. Tubers were sampled at 42, 56, 87, 101, 115, and 143 days after physiological maturity (DAPM). Obiaoturugo exhibited a short dormant phenotype and sprouted at 101-DAPM, whereas TDr1100873 exhibited a long dormant phenotype and sprouted at 143-DAPM. Significant metabolic changes were observed in non-structural sugar parameters, dry matter, and moisture content in Obiaoturugo from 56-DAPM, whereas in TDr1100873, significant metabolic changes were observed from 101-DAPM. It was observed that the onset of these metabolic changes occurred at a point when the tubers of both genotypes exhibited a dry matter content of 60\%, indicating that a dry matter content of 60\% might be a critical threshold for white yam tuber sprouting. Non-reducing sugars increased by 9-10-fold during sprouting in both genotypes, which indicates their key role in tuber dormancy regulation in white yam. This result implicates that some key sugar metabolites can be targeted for dormancy manipulation of the yam crop.}, language = {en} } @article{MunzJakobBorisjuk2016, author = {Munz, Eberhard and Jakob, Peter M. and Borisjuk, Ljudmilla}, title = {The potential of nuclear magnetic resonance to track lipids in planta}, series = {Biochimie}, volume = {130}, journal = {Biochimie}, doi = {10.1016/j.biochi.2016.07.014}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186828}, pages = {97-108}, year = {2016}, abstract = {Nuclear Magnetic Resonance (NMR) provides a highly flexible platform for non invasive analysis and imaging biological samples, since the manipulation of nuclear spin allows the tailoring of experiments to maximize the informativeness of the data. MRI is capable of visualizing a holistic picture of the lipid storage in living plant/seed. This review has sought to explain how the technology can be used to acquire functional and physiological data from plant samples, and how to exploit it to characterize lipid deposition in vivo. At the same time, we have referred to the current limitations of NMR technology as applied to plants, and in particular of the difficulty of transferring methodologies optimized for animal/medical subjects to plant ones. A forward look into likely developments in the field is included, anticipating its key future role in the study of living plant.}, language = {en} } @article{MirasSeyfriedPhinikaridouetal.2014, author = {Miras, Alexander D. and Seyfried, Florian and Phinikaridou, Alkystis and Andia, Marcelo E. and Christakis, Ioannis and Spector, Alan C. and Botnar, Rene M. and le Roux, Carel W.}, title = {Rats Fed Diets with Different Energy Contribution from Fat Do Not Differ in Adiposity}, series = {OBESITY FACTS}, volume = {7}, journal = {OBESITY FACTS}, number = {5}, doi = {10.1159/000368622}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115249}, pages = {302-310}, year = {2014}, abstract = {Objective: To determine whether rats reaching the same body mass, having been fed either a low-fat (LFD) or a high-fat diet (HFD), differ in white adipose tissue (WAT) deposition. Methods: In experiment 1, 22 Sprague-Dawley rats of the same age were divided into 11 rats with body mass below the batch median and fed a HFD, and 11 above the median and fed a LFD. In experiment 2, 20 Sprague-Dawley rats of the same age and starting body mass were randomised to either a HFD or LFD. When all groups reached similar final body mass, WAT was quantified using magnetic resonance imaging (MRI), dissection, and plasma leptin. Results: In experiment 1, both groups reached similar final body mass at the same age; in experiment 2 the HFD group reached similar final body mass earlier than the LFD group. There were no significant differences in WAT as assessed by MRI or leptin between the HFD and LFD groups in both experiments. Dissection revealed a trend for higher retroperitoneal and epididymal adiposity in the HFD groups in both experiments. Conclusions: We conclude that at similar body mass, adiposity is independent of the macronutrient composition of the feeding regimen used to achieve it. (C) 2014 S Karger GmbH, Freiburg}, language = {en} } @article{MayerLoefflerLozaValdesetal.2019, author = {Mayer, Alexander E. and L{\"o}ffler, Mona C. and Loza Vald{\´e}s, Angel E. and Schmitz, Werner and El-Merahbi, Rabih and Trujillo-Viera, Jonathan and Erk, Manuela and Zhang, Thianzhou and Braun, Ursula and Heikenwalder, Mathias and Leitges, Michael and Schulze, Almut and Sumara, Grzegorz}, title = {The kinase PKD3 provides negative feedback on cholesterol and triglyceride synthesis by suppressing insulin signaling}, series = {Science Signaling}, journal = {Science Signaling}, edition = {accepted manuscript}, doi = {10.1126/scisignal.aav9150}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250025}, year = {2019}, abstract = {Hepatic activation of protein kinase C (PKC) isoforms by diacylglycerol (DAG) promotes insulin resistance and contributes to the development of type 2 diabetes (T2D). The closely related protein kinase D (PKD) isoforms act as effectors for DAG and PKC. Here, we showed that PKD3 was the predominant PKD isoform expressed in hepatocytes and was activated by lipid overload. PKD3 suppressed the activity of downstream insulin effectors including the kinase AKT and mechanistic target of rapamycin complex 1 and 2 (mTORC1 and mTORC2). Hepatic deletion of PKD3 in mice improved insulin-induced glucose tolerance. However, increased insulin signaling in the absence of PKD3 promoted lipogenesis mediated by SREBP (sterol regulatory element-binding protein) and consequently increased triglyceride and cholesterol content in the livers of PKD3-deficient mice fed a high-fat diet. Conversely, hepatic-specific overexpression of a constitutively active PKD3 mutant suppressed insulin-induced signaling and caused insulin resistance. Our results indicate that PKD3 provides feedback on hepatic lipid production and suppresses insulin signaling. Therefore, manipulation of PKD3 activity could be used to decrease hepatic lipid content or improve hepatic insulin sensitivity.}, language = {en} } @article{MajumderJugovicSauletal.2021, author = {Majumder, Snigdha and Jugovic, Isabelle and Saul, Domenica and Bell, Luisa and Hundhausen, Nadine and Seal, Rishav and Beilhack, Andreas and Rosenwald, Andreas and Mougiakakos, Dimitrios and Berberich-Siebelt, Friederike}, title = {Rapid and Efficient Gene Editing for Direct Transplantation of Naive Murine Cas9\(^+\) T Cells}, series = {Frontiers in Immunology}, volume = {12}, journal = {Frontiers in Immunology}, issn = {1664-3224}, doi = {10.3389/fimmu.2021.683631}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242896}, year = {2021}, abstract = {Gene editing of primary T cells is a difficult task. However, it is important for research and especially for clinical T-cell transfers. CRISPR/Cas9 is the most powerful gene-editing technique. It has to be applied to cells by either retroviral transduction or electroporation of ribonucleoprotein complexes. Only the latter is possible with resting T cells. Here, we make use of Cas9 transgenic mice and demonstrate nucleofection of pre-stimulated and, importantly, of naive CD3\(^+\) T cells with guideRNA only. This proved to be rapid and efficient with no need of further selection. In the mixture of Cas9\(^+\)CD3\(^+\) T cells, CD4\(^+\) and CD8\(^+\) conventional as well as regulatory T cells were targeted concurrently. IL-7 supported survival and naivety in vitro, but T cells were also transplantable immediately after nucleofection and elicited their function like unprocessed T cells. Accordingly, metabolic reprogramming reached normal levels within days. In a major mismatch model of GvHD, not only ablation of NFATc1 and/or NFATc2, but also of the NFAT-target gene IRF4 in na{\"i}ve primary murine Cas9\(^+\)CD3\(^+\) T cells by gRNA-only nucleofection ameliorated GvHD. However, pre-activated murine T cells could not achieve long-term protection from GvHD upon single NFATc1 or NFATc2 knockout. This emphasizes the necessity of gene-editing and transferring unstimulated human T cells during allogenic hematopoietic stem cell transplantation.}, language = {en} } @article{LillaFuellgrafStetteretal.2017, author = {Lilla, Nadine and F{\"u}llgraf, Hannah and Stetter, Christian and K{\"o}hler, Stefan and Ernestus, Ralf-Ingo and Westermaier, Thomas}, title = {First Description of Reduced Pyruvate Dehydrogenase Enzyme Activity Following Subarachnoid Hemorrhage (SAH)}, series = {Frontiers in Neuroscience}, volume = {11}, journal = {Frontiers in Neuroscience}, number = {37}, doi = {10.3389/fnins.2017.00037}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157636}, year = {2017}, abstract = {Object: Several previous studies reported metabolic derangements and an accumulation of metabolic products in the early phase of experimental subarachnoid hemorrhage (SAH), which may contribute to secondary brain damage. This may be a result of deranged oxygen utilization due to enzymatic dysfunction in aerobic glucose metabolism. This study was performed to investigate, if pyruvate dehydrogenase enzyme (PDH) is affected in its activity giving further hints for a derangement of oxidative metabolism. Methods: Eighteen male Sprague-Dawley rats were randomly assigned to one of two experimental groups (n = 9): (1) SAH induced by the endovascular filament model and (2) sham-operated controls. Mean arterial blood pressure (MABP), intracranial pressure (ICP), and local cerebral blood flow (LCBF; laser-Doppler flowmetry) were continuously monitored from 30 min before until 3 h after SAH. Thereafter, the animals were sacrificed and PDH activity was measured by ELISA. Results: PDH activity was significantly reduced in animals subjected to SAH compared to controls. Conclusion: The results of this study demonstrate for the first time a reduction of PDH activity following SAH, independent of supply of substrates and may be an independent factor contributing to a derangement of oxidative metabolism, failure of oxygen utilization, and secondary brain damage.}, language = {en} } @article{LiangRiosMiguelJaricketal.2021, author = {Liang, Chunguang and Rios-Miguel, Ana B. and Jarick, Marcel and Neurgaonkar, Priya and Girard, Myriam and Fran{\c{c}}ois, Patrice and Schrenzel, Jacques and Ibrahim, Eslam S. and Ohlsen, Knut and Dandekar, Thomas}, title = {Staphylococcus aureus transcriptome data and metabolic modelling investigate the interplay of Ser/Thr kinase PknB, its phosphatase Stp, the glmR/yvcK regulon and the cdaA operon for metabolic adaptation}, series = {Microorganisms}, volume = {9}, journal = {Microorganisms}, number = {10}, issn = {2076-2607}, doi = {10.3390/microorganisms9102148}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248459}, year = {2021}, abstract = {Serine/threonine kinase PknB and its corresponding phosphatase Stp are important regulators of many cell functions in the pathogen S. aureus. Genome-scale gene expression data of S. aureus strain NewHG (sigB\(^+\)) elucidated their effect on physiological functions. Moreover, metabolic modelling from these data inferred metabolic adaptations. We compared wild-type to deletion strains lacking pknB, stp or both. Ser/Thr phosphorylation of target proteins by PknB switched amino acid catabolism off and gluconeogenesis on to provide the cell with sufficient components. We revealed a significant impact of PknB and Stp on peptidoglycan, nucleotide and aromatic amino acid synthesis, as well as catabolism involving aspartate transaminase. Moreover, pyrimidine synthesis was dramatically impaired by stp deletion but only slightly by functional loss of PknB. In double knockouts, higher activity concerned genes involved in peptidoglycan, purine and aromatic amino acid synthesis from glucose but lower activity of pyrimidine synthesis from glucose compared to the wild type. A second transcriptome dataset from S. aureus NCTC 8325 (sigB\(^-\)) validated the predictions. For this metabolic adaptation, PknB was found to interact with CdaA and the yvcK/glmR regulon. The involved GlmR structure and the GlmS riboswitch were modelled. Furthermore, PknB phosphorylation lowered the expression of many virulence factors, and the study shed light on S. aureus infection processes.}, language = {en} } @article{KochCappelNockeretal.2013, author = {Koch, Oliver and Cappel, Daniel and Nocker, Monika and J{\"a}ger, Timo and Floh{\´e}, Leopold and Sotriffer, Christoph A. and Selzer, Paul M.}, title = {Molecular Dynamics Reveal Binding Mode of Glutathionylspermidine by Trypanothione Synthetase}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {2}, doi = {10.1371/journal.pone.0056788}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131070}, pages = {e56788}, year = {2013}, abstract = {The trypanothione synthetase (TryS) catalyses the two-step biosynthesis of trypanothione from spermidine and glutathione and is an attractive new drug target for the development of trypanocidal and antileishmanial drugs, especially since the structural information of TryS from Leishmania major has become available. Unfortunately, the TryS structure was solved without any of the substrates and lacks loop regions that are mechanistically important. This contribution describes docking and molecular dynamics simulations that led to further insights into trypanothione biosynthesis and, in particular, explains the binding modes of substrates for the second catalytic step. The structural model essentially confirm previously proposed binding sites for glutathione, ATP and two \(Mg^{2+}\) ions, which appear identical for both catalytic steps. The analysis of an unsolved loop region near the proposed spermidine binding site revealed a new pocket that was demonstrated to bind glutathionylspermidine in an inverted orientation. For the second step of trypanothione synthesis glutathionylspermidine is bound in a way that preferentially allows \(N^1\)-glutathionylation of \(N^8\)-glutathionylspermidine, classifying \(N^8\)-glutathionylspermidine as the favoured substrate. By inhibitor docking, the binding site for \(N^8\)-glutathionylspermidine was characterised as druggable.}, language = {en} } @article{KaltdorfSrivastavaGuptaetal.2016, author = {Kaltdorf, Martin and Srivastava, Mugdha and Gupta, Shishir K. and Liang, Chunguang and Binder, Jasmin and Dietl, Anna-Maria and Meir, Zohar and Haas, Hubertus and Osherov, Nir and Krappmann, Sven and Dandekar, Thomas}, title = {Systematic Identification of Anti-Fungal Drug Targets by a Metabolic Network Approach}, series = {Frontiers in Molecular Bioscience}, volume = {3}, journal = {Frontiers in Molecular Bioscience}, doi = {10.3389/fmolb.2016.00022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147396}, pages = {22}, year = {2016}, abstract = {New antimycotic drugs are challenging to find, as potential target proteins may have close human orthologs. We here focus on identifying metabolic targets that are critical for fungal growth and have minimal similarity to targets among human proteins. We compare and combine here: (I) direct metabolic network modeling using elementary mode analysis and flux estimates approximations using expression data, (II) targeting metabolic genes by transcriptome analysis of condition-specific highly expressed enzymes, and (III) analysis of enzyme structure, enzyme interconnectedness ("hubs"), and identification of pathogen-specific enzymes using orthology relations. We have identified 64 targets including metabolic enzymes involved in vitamin synthesis, lipid, and amino acid biosynthesis including 18 targets validated from the literature, two validated and five currently examined in own genetic experiments, and 38 further promising novel target proteins which are non-orthologous to human proteins, involved in metabolism and are highly ranked drug targets from these pipelines.}, language = {en} } @article{JanzWalzCirnuetal.2024, author = {Janz, Anna and Walz, Katharina and Cirnu, Alexandra and Surjanto, Jessica and Urlaub, Daniela and Leskien, Miriam and Kohlhaas, Michael and Nickel, Alexander and Brand, Theresa and Nose, Naoko and W{\"o}rsd{\"o}rfer, Philipp and Wagner, Nicole and Higuchi, Takahiro and Maack, Christoph and Dudek, Jan and Lorenz, Kristina and Klopocki, Eva and Erg{\"u}n, S{\"u}leyman and Duff, Henry J. and Gerull, Brenda}, title = {Mutations in DNAJC19 cause altered mitochondrial structure and increased mitochondrial respiration in human iPSC-derived cardiomyocytes}, series = {Molecular Metabolism}, volume = {79}, journal = {Molecular Metabolism}, issn = {2212-8778}, doi = {10.1016/j.molmet.2023.101859}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350393}, year = {2024}, abstract = {Highlights • Loss of DNAJC19's DnaJ domain disrupts cardiac mitochondrial structure, leading to abnormal cristae formation in iPSC-CMs. • Impaired mitochondrial structures lead to an increased mitochondrial respiration, ROS and an elevated membrane potential. • Mutant iPSC-CMs show sarcomere dysfunction and a trend to more arrhythmias, resembling DCMA-associated cardiomyopathy. Background Dilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from truncating mutations in DNAJC19, which encodes an inner mitochondrial membrane protein. Clinical features include an early onset, often life-threatening, cardiomyopathy associated with other metabolic features. Here, we aim to understand the metabolic and pathophysiological mechanisms of mutant DNAJC19 for the development of cardiomyopathy. Methods We generated induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two affected siblings with DCMA and a gene-edited truncation variant (tv) of DNAJC19 which all lack the conserved DnaJ interaction domain. The mutant iPSC-CMs and their respective control cells were subjected to various analyses, including assessments of morphology, metabolic function, and physiological consequences such as Ca\(^{2+}\) kinetics, contractility, and arrhythmic potential. Validation of respiration analysis was done in a gene-edited HeLa cell line (DNAJC19tv\(_{HeLa}\)). Results Structural analyses revealed mitochondrial fragmentation and abnormal cristae formation associated with an overall reduced mitochondrial protein expression in mutant iPSC-CMs. Morphological alterations were associated with higher oxygen consumption rates (OCRs) in all three mutant iPSC-CMs, indicating higher electron transport chain activity to meet cellular ATP demands. Additionally, increased extracellular acidification rates suggested an increase in overall metabolic flux, while radioactive tracer uptake studies revealed decreased fatty acid uptake and utilization of glucose. Mutant iPSC-CMs also showed increased reactive oxygen species (ROS) and an elevated mitochondrial membrane potential. Increased mitochondrial respiration with pyruvate and malate as substrates was observed in mutant DNAJC19tv HeLa cells in addition to an upregulation of respiratory chain complexes, while cellular ATP-levels remain the same. Moreover, mitochondrial alterations were associated with increased beating frequencies, elevated diastolic Ca\(^{2+}\) concentrations, reduced sarcomere shortening and an increased beat-to-beat rate variability in mutant cell lines in response to β-adrenergic stimulation. Conclusions Loss of the DnaJ domain disturbs cardiac mitochondrial structure with abnormal cristae formation and leads to mitochondrial dysfunction, suggesting that DNAJC19 plays an essential role in mitochondrial morphogenesis and biogenesis. Moreover, increased mitochondrial respiration, altered substrate utilization, increased ROS production and abnormal Ca\(^{2+}\) kinetics provide insights into the pathogenesis of DCMA-related cardiomyopathy.}, language = {en} } @article{DembekBarquistBoinettetal.2015, author = {Dembek, Marcin and Barquist, Lars and Boinett, Christine J. and Cain, Amy K. and Mayho, Matthew and Lawley, Trevor D. and Fairweather, Neil F. and Fagan, Robert P.}, title = {High-throughput analysis of gene essentiality and sporulation in Clostridium difficile}, series = {mBio}, volume = {6}, journal = {mBio}, number = {2}, doi = {10.1128/mBio.02383-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143745}, pages = {e02383-14}, year = {2015}, abstract = {Clostridium difficile is the most common cause of antibiotic-associated intestinal infections and a significant cause of morbidity and mortality. Infection with C. difficile requires disruption of the intestinal microbiota, most commonly by antibiotic usage. Therapeutic intervention largely relies on a small number of broad-spectrum antibiotics, which further exacerbate intestinal dysbiosis and leave the patient acutely sensitive to reinfection. Development of novel targeted therapeutic interventions will require a detailed knowledge of essential cellular processes, which represent attractive targets, and species-specific processes, such as bacterial sporulation. Our knowledge of the genetic basis of C. difficile infection has been hampered by a lack of genetic tools, although recent developments have made some headway in addressing this limitation. Here we describe the development of a method for rapidly generating large numbers of transposon mutants in clinically important strains of C. difficile. We validated our transposon mutagenesis approach in a model strain of C. difficile and then generated a comprehensive transposon library in the highly virulent epidemic strain R20291 (027/BI/NAP1) containing more than 70,000 unique mutants. Using transposon-directed insertion site sequencing (TraDIS), we have identified a core set of 404 essential genes, required for growth in vitro. We then applied this technique to the process of sporulation, an absolute requirement for C. difficile transmission and pathogenesis, identifying 798 genes that are likely to impact spore production. The data generated in this study will form a valuable resource for the community and inform future research on this important human pathogen.}, language = {en} } @article{DandekarFieselmannPoppetal.2012, author = {Dandekar, Thomas and Fieselmann, Astrid and Popp, Jasmin and Hensel, Michael}, title = {Salmonella enterica: a surprisingly well-adapted intracellular lifestyle}, series = {Frontiers in Microbiology}, journal = {Frontiers in Microbiology}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123135}, year = {2012}, abstract = {The infectious intracellular lifestyle of Salmonella enterica relies on the adaptation to nutritional conditions within the Salmonella-containing vacuole (SCV) in host cells. We summarize latest results on metabolic requirements for Salmonella during infection. This includes intracellular phenotypes of mutant strains based on metabolic modeling and experimental tests, isotopolog profiling using (13)C-compounds in intracellular Salmonella, and complementation of metabolic defects for attenuated mutant strains towards a comprehensive understanding of the metabolic requirements of the intracellular lifestyle of Salmonella. Helpful for this are also genomic comparisons. We outline further recent studies and which analyses of intracellular phenotypes and improved metabolic simulations were done and comment on technical required steps as well as progress involved in the iterative refinement of metabolic flux models, analyses of mutant phenotypes, and isotopolog analyses. Salmonella lifestyle is well-adapted to the SCV and its specific metabolic requirements. Salmonella metabolism adapts rapidly to SCV conditions, the metabolic generalist Salmonella is quite successful in host infection.}, language = {en} } @article{DandekarFieselmannFischeretal.2014, author = {Dandekar, Thomas and Fieselmann, Astrid and Fischer, Eva and Popp, Jasmin and Hensel, Michael and Noster, Janina}, title = {Salmonella—how a metabolic generalist adopts an intracellular lifestyle during infection}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {4}, journal = {Frontiers in Cellular and Infection Microbiology}, number = {191}, issn = {2235-2988}, doi = {10.3389/fcimb.2014.00191}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120686}, year = {2014}, abstract = {The human-pathogenic bacterium Salmonella enterica adjusts and adapts to different environments while attempting colonization. In the course of infection nutrient availabilities change drastically. New techniques, "-omics" data and subsequent integration by systems biology improve our understanding of these changes. We review changes in metabolism focusing on amino acid and carbohydrate metabolism. Furthermore, the adaptation process is associated with the activation of genes of the Salmonella pathogenicity islands (SPIs). Anti-infective strategies have to take these insights into account and include metabolic and other strategies. Salmonella infections will remain a challenge for infection biology.}, language = {en} } @article{DandekarFieselmannFischeretal.2015, author = {Dandekar, Thomas and Fieselmann, Astrid and Fischer, Eva and Popp, Jasmin and Hensel, Michael and Noster, Janina}, title = {Salmonella - how a metabolic generalist adopts an intracellular lifestyle during infection}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {4}, journal = {Frontiers in Cellular and Infection Microbiology}, number = {191}, doi = {10.3389/fcimb.2014.00191}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149029}, year = {2015}, abstract = {The human-pathogenic bacterium Salmonella enterica adjusts and adapts to different environments while attempting colonization. In the course of infection nutrient availabilities change drastically. New techniques, "-omics" data and subsequent integration by systems biology improve our understanding of these changes. We review changes in metabolism focusing on amino acid and carbohydrate metabolism. Furthermore, the adaptation process is associated with the activation of genes of the Salmonella pathogenicity islands (SPIs). Anti-infective strategies have to take these insights into account and include metabolic and other strategies. Salmonella infections will remain a challenge for infection biology.}, language = {en} } @article{DandekarEisenreich2015, author = {Dandekar, Thomas and Eisenreich, Wolfgang}, title = {Host-adapted metabolism and its regulation in bacterial pathogens}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {5}, journal = {Frontiers in Cellular and Infection Microbiology}, number = {28}, issn = {2235-2988}, doi = {10.3389/fcimb.2015.00028}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196876}, year = {2015}, abstract = {No abstract available.}, language = {en} } @article{BensaadFavaroLewisetal.2014, author = {Bensaad, Karim and Favaro, Elena and Lewis, Caroline A. and Peck, Barrie and Lord, Simon and Collins, Jennifer M. and Pinnick, Katherine E. and Wigfield, Simon and Buffa, Francesca M. and Li, Ji-Liang and Zhang, Qifeng and Wakelam, Michael J. O. and Karpe, Fredrik and Schulze, Almut and Harris, Adrian L.}, title = {Fatty Acid Uptake and Lipid Storage Induced by HIF-1 alpha Contribute to Cell Growth and Survival after Hypoxia-Reoxygenation}, series = {Cell Reports}, volume = {9}, journal = {Cell Reports}, number = {1}, issn = {2211-1247}, doi = {10.1016/j.celrep.2014.08.056}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115162}, pages = {349-365}, year = {2014}, abstract = {An in vivo model of antiangiogenic therapy allowed us to identify genes upregulated by bevacizumab treatment, including Fatty Acid Binding Protein 3 (FABP3) and FABP7, both of which are involved in fatty acid uptake. In vitro, both were induced by hypoxia in a hypoxia-inducible factor-1 alpha (HIF-1 alpha)-dependent manner. There was a significant lipid droplet (LD) accumulation in hypoxia that was time and O-2 concentration dependent. Knockdown of endogenous expression of FABP3, FABP7, or Adipophilin (an essential LD structural component) significantly impaired LD formation under hypoxia. We showed that LD accumulation is due to FABP3/7-dependent fatty acid uptake while de novo fatty acid synthesis is repressed in hypoxia. We also showed that ATP production occurs via beta-oxidation or glycogen degradation in a cell-type-dependent manner in hypoxia-reoxygenation. Finally, inhibition of lipid storage reduced protection against reactive oxygen species toxicity, decreased the survival of cells subjected to hypoxia-reoxygenation in vitro, and strongly impaired tumorigenesis in vivo.}, language = {en} } @article{AmpattuHagmannLiangetal.2017, author = {Ampattu, Biju Joseph and Hagmann, Laura and Liang, Chunguang and Dittrich, Marcus and Schl{\"u}ter, Andreas and Blom, Jochen and Krol, Elizaveta and Goesmann, Alexander and Becker, Anke and Dandekar, Thomas and M{\"u}ller, Tobias and Schoen, Christoph}, title = {Transcriptomic buffering of cryptic genetic variation contributes to meningococcal virulence}, series = {BMC Genomics}, volume = {18}, journal = {BMC Genomics}, number = {282}, doi = {10.1186/s12864-017-3616-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157534}, year = {2017}, abstract = {Background: Commensal bacteria like Neisseria meningitidis sometimes cause serious disease. However, genomic comparison of hyperinvasive and apathogenic lineages did not reveal unambiguous hints towards indispensable virulence factors. Here, in a systems biological approach we compared gene expression of the invasive strain MC58 and the carriage strain α522 under different ex vivo conditions mimicking commensal and virulence compartments to assess the strain-specific impact of gene regulation on meningococcal virulence. Results: Despite indistinguishable ex vivo phenotypes, both strains differed in the expression of over 500 genes under infection mimicking conditions. These differences comprised in particular metabolic and information processing genes as well as genes known to be involved in host-damage such as the nitrite reductase and numerous LOS biosynthesis genes. A model based analysis of the transcriptomic differences in human blood suggested ensuing metabolic flux differences in energy, glutamine and cysteine metabolic pathways along with differences in the activation of the stringent response in both strains. In support of the computational findings, experimental analyses revealed differences in cysteine and glutamine auxotrophy in both strains as well as a strain and condition dependent essentiality of the (p)ppGpp synthetase gene relA and of a short non-coding AT-rich repeat element in its promoter region. Conclusions: Our data suggest that meningococcal virulence is linked to transcriptional buffering of cryptic genetic variation in metabolic genes including global stress responses. They further highlight the role of regulatory elements for bacterial virulence and the limitations of model strain approaches when studying such genetically diverse species as N. meningitidis.}, language = {en} }