@article{WuZhaoHochreinetal.2023,
  author    = {Wu, Hao and Zhao, Xiufeng and Hochrein, Sophia M. and Eckstein, Miriam and Gubert, Gabriela F. and Kn{\"o}pper, Konrad and Mansilla, Ana Maria and {\"O}ner, Arman and Doucet-Ladev{\`e}ze, Remi and Schmitz, Werner and Ghesqui{\`e}re, Bart and Theurich, Sebastian and Dudek, Jan and Gasteiger, Georg and Zernecke, Alma and Kobold, Sebastian and Kastenm{\"u}ller, Wolfgang and Vaeth, Martin},
  title     = {Mitochondrial dysfunction promotes the transition of precursor to terminally exhausted T cells through HIF-1α-mediated glycolytic reprogramming},
  series = {Nature Communications},
  volume    = {14},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-023-42634-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358052},
  year      = {2023},
  abstract  = {T cell exhaustion is a hallmark of cancer and persistent infections, marked by inhibitory receptor upregulation, diminished cytokine secretion, and impaired cytolytic activity. Terminally exhausted T cells are steadily replenished by a precursor population (Tpex), but the metabolic principles governing Tpex maintenance and the regulatory circuits that control their exhaustion remain incompletely understood. Using a combination of gene-deficient mice, single-cell transcriptomics, and metabolomic analyses, we show that mitochondrial insufficiency is a cell-intrinsic trigger that initiates the functional exhaustion of T cells. At the molecular level, we find that mitochondrial dysfunction causes redox stress, which inhibits the proteasomal degradation of hypoxia-inducible factor 1α (HIF-1α) and promotes the transcriptional and metabolic reprogramming of Tpex cells into terminally exhausted T cells. Our findings also bear clinical significance, as metabolic engineering of chimeric antigen receptor (CAR) T cells is a promising strategy to enhance the stemness and functionality of Tpex cells for cancer immunotherapy.},
  language  = {en}
}
@article{VollmuthSchlickerGuoetal.2022,
  author    = {Vollmuth, Nadine and Schlicker, Lisa and Guo, Yongxia and Hovhannisyan, Pargev and Janaki-Raman, Sudha and Kurmasheva, Naziia and Schmitz, Werner and Schulze, Almut and Stelzner, Kathrin and Rajeeve, Karthika and Rudel, Thomas},
  title     = {c-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis},
  series = {eLife},
  volume    = {11},
  journal   = {eLife},
  doi       = {10.7554/eLife.76721},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301385},
  year      = {2022},
  abstract  = {Chlamydia trachomatis (Ctr) can persist over extended times within their host cell and thereby establish chronic infections. One of the major inducers of chlamydial persistence is interferon-gamma (IFN-γ) released by immune cells as a mechanism of immune defence. IFN-γ activates the catabolic depletion of L-tryptophan (Trp) via indoleamine-2,3-dioxygenase (IDO), resulting in persistent Ctr. Here, we show that IFN-γ induces the downregulation of c-Myc, the key regulator of host cell metabolism, in a STAT1-dependent manner. Expression of c-Myc rescued Ctr from IFN-γ-induced persistence in cell lines and human fallopian tube organoids. Trp concentrations control c-Myc levels most likely via the PI3K-GSK3β axis. Unbiased metabolic analysis revealed that Ctr infection reprograms the host cell tricarboxylic acid (TCA) cycle to support pyrimidine biosynthesis. Addition of TCA cycle intermediates or pyrimidine/purine nucleosides to infected cells rescued Ctr from IFN-γ-induced persistence. Thus, our results challenge the longstanding hypothesis of Trp depletion through IDO as the major mechanism of IFN-γ-induced metabolic immune defence and significantly extends the understanding of the role of IFN-γ as a broad modulator of host cell metabolism.},
  language  = {en}
}
@article{VollandKauppSchmitzetal.2022,
  author    = {Volland, Julian Manuel and Kaupp, Johannes and Schmitz, Werner and W{\"u}nsch, Anna Chiara and Balint, Julia and M{\"o}llmann, Marc and El-Mesery, Mohamed and Frackmann, Kyra and Peter, Leslie and Hartmann, Stefan and K{\"u}bler, Alexander Christian and Seher, Axel},
  title     = {Mass spectrometric metabolic fingerprinting of 2-Deoxy-D-Glucose (2-DG)-induced inhibition of glycolysis and comparative analysis of methionine restriction versus glucose restriction under perfusion culture in the murine L929 model system},
  series = {International Journal of Molecular Sciences},
  volume    = {23},
  journal   = {International Journal of Molecular Sciences},
  number    = {16},
  issn      = {1422-0067},
  doi       = {10.3390/ijms23169220},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286007},
  year      = {2022},
  abstract  = {All forms of restriction, from caloric to amino acid to glucose restriction, have been established in recent years as therapeutic options for various diseases, including cancer. However, usually there is no direct comparison between the different restriction forms. Additionally, many cell culture experiments take place under static conditions. In this work, we used a closed perfusion culture in murine L929 cells over a period of 7 days to compare methionine restriction (MetR) and glucose restriction (LowCarb) in the same system and analysed the metabolome by liquid chromatography mass spectrometry (LC-MS). In addition, we analysed the inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) over a period of 72 h. 2-DG induced very fast a low-energy situation by a reduced glycolysis metabolite flow rate resulting in pyruvate, lactate, and ATP depletion. Under perfusion culture, both MetR and LowCarb were established on the metabolic level. Interestingly, over the period of 7 days, the metabolome of MetR and LowCarb showed more similarities than differences. This leads to the conclusion that the conditioned medium, in addition to the different restriction forms, substantially reprogramm the cells on the metabolic level.},
  language  = {en}
}
@article{ThomasFiebigKuhnetal.2023,
  author    = {Thomas, Sarah and Fiebig, Juliane E. and Kuhn, Eva-Maria and Mayer, Dominik S. and Filbeck, Sebastian and Schmitz, Werner and Krischke, Markus and Gropp, Roswitha and Mueller, Thomas D.},
  title     = {Design of glycoengineered IL-4 antagonists employing chemical and biosynthetic glycosylation},
  series = {ACS Omega},
  volume    = {8},
  journal   = {ACS Omega},
  number    = {28},
  issn      = {2470-1343},
  doi       = {10.1021/acsomega.3c00726},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350278},
  pages     = {24841-24852},
  year      = {2023},
  abstract  = {Interleukin-4 (IL-4) plays a key role in atopic diseases. It coordinates T-helper cell differentiation to subtype 2, thereby directing defense toward humoral immunity. Together with Interleukin-13, IL-4 further induces immunoglobulin class switch to IgE. Antibodies of this type activate mast cells and basophilic and eosinophilic granulocytes, which release pro-inflammatory mediators accounting for the typical symptoms of atopic diseases. IL-4 and IL-13 are thus major targets for pharmaceutical intervention strategies to treat atopic diseases. Besides neutralizing antibodies against IL-4, IL-13, or its receptors, IL-4 antagonists can present valuable alternatives. Pitrakinra, an Escherichia coli-derived IL-4 antagonist, has been evaluated in clinical trials for asthma treatment in the past; however, deficits such as short serum lifetime and potential immunogenicity among others stopped further development. To overcome such deficits, PEGylation of therapeutically important proteins has been used to increase the lifetime and proteolytic stability. As an alternative, glycoengineering is an emerging strategy used to improve pharmacokinetics of protein therapeutics. In this study, we have established different strategies to attach glycan moieties to defined positions in IL-4. Different chemical attachment strategies employing thiol chemistry were used to attach a glucose molecule at amino acid position 121, thereby converting IL-4 into a highly effective antagonist. To enhance the proteolytic stability of this IL-4 antagonist, additional glycan structures were introduced by glycoengineering utilizing eucaryotic expression. IL-4 antagonists with a combination of chemical and biosynthetic glycoengineering could be useful as therapeutic alternatives to IL-4 neutralizing antibodies already used to treat atopic diseases.},
  language  = {en}
}
@article{SchmitzRiesKodereretal.2021,
  author    = {Schmitz, Werner and Ries, Elena and Koderer, Corinna and V{\"o}lter, Maximilian Friedrich and W{\"u}nsch, Anna Chiara and El-Mesery, Mohamed and Frackmann, Kyra and K{\"u}bler, Alexander Christian and Linz, Christian and Seher, Axel},
  title     = {Cysteine restriction in murine L929 fibroblasts as an alternative strategy to methionine restriction in cancer therapy},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {21},
  issn      = {1422-0067},
  doi       = {10.3390/ijms222111630},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265486},
  year      = {2021},
  abstract  = {Methionine restriction (MetR) is an efficient method of amino acid restriction (AR) in cells and organisms that induces low energy metabolism (LEM) similar to caloric restriction (CR). The implementation of MetR as a therapy for cancer or other diseases is not simple since the elimination of a single amino acid in the diet is difficult. However, the in vivo turnover rate of cysteine is usually higher than the rate of intake through food. For this reason, every cell can enzymatically synthesize cysteine from methionine, which enables the use of specific enzymatic inhibitors. In this work, we analysed the potential of cysteine restriction (CysR) in the murine cell line L929. This study determined metabolic fingerprints using mass spectrometry (LC/MS). The profiles were compared with profiles created in an earlier work under MetR. The study was supplemented by proliferation studies using D-amino acid analogues and inhibitors of intracellular cysteine synthesis. CysR showed a proliferation inhibition potential comparable to that of MetR. However, the metabolic footprints differed significantly and showed that CysR does not induce classic LEM at the metabolic level. Nevertheless, CysR offers great potential as an alternative for decisive interventions in general and tumour metabolism at the metabolic level.},
  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{PeterBultinckMyantetal.2014,
  author    = {Peter, Stefanie and Bultinck, Jennyfer and Myant, Kevin and Jaenicke, Laura A. and Walz, Susanne and M{\"u}ller, Judith and Gmachl, Michael and Treu, Matthias and Boehmelt, Guido and Ade, Casten P. and Schmitz, Werner and Wiegering, Armin and Otto, Christoph and Popov, Nikita and Sansom, Owen and Kraut, Norbert and Eilers, Martin},
  title     = {H Tumor cell-specific inhibition of MYC function using small molecule inhibitors of the HUWE1 ubiquitin ligase},
  series = {EMBO Molecular Medicine},
  volume    = {6},
  journal   = {EMBO Molecular Medicine},
  number    = {12},
  issn      = {1757-4684},
  doi       = {10.15252/emmm.201403927},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118132},
  pages     = {1525-41},
  year      = {2014},
  abstract  = {Deregulated expression of MYC is a driver of colorectal carcinogenesis, necessitating novel strategies to inhibit MYC function. The ubiquitin ligase HUWE1 (HECTH9, ARF-BP1, MULE) associates with both MYC and the MYC-associated protein MIZ1. We show here that HUWE1 is required for growth of colorectal cancer cells in culture and in orthotopic xenograft models. Using high-throughput screening, we identify small molecule inhibitors of HUWE1, which inhibit MYC-dependent transactivation in colorectal cancer cells, but not in stem and normal colon epithelial cells. Inhibition of HUWE1 stabilizes MIZ1. MIZ1 globally accumulates on MYC target genes and contributes to repression of MYC-activated target genes upon HUWE1 inhibition. Our data show that transcriptional activation by MYC in colon cancer cells requires the continuous degradation of MIZ1 and identify a novel principle that allows for inhibition of MYC function in tumor cells.},
  language  = {en}
}
@article{PeixotoJanakiRamanSchlickeretal.2021,
  author    = {Peixoto, Joana and Janaki-Raman, Sudha and Schlicker, Lisa and Schmitz, Werner and Walz, Susanne and Winkelkotte, Alina M. and Herold-Mende, Christel and Soares, Paula and Schulze, Almut and Lima, Jorge},
  title     = {Integrated metabolomics and transcriptomics analysis of monolayer and neurospheres from established glioblastoma cell lines},
  series = {Cancers},
  volume    = {13},
  journal   = {Cancers},
  number    = {6},
  issn      = {2072-6694},
  doi       = {10.3390/cancers13061327},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234110},
  year      = {2021},
  abstract  = {Altered metabolic processes contribute to carcinogenesis by modulating proliferation, survival and differentiation. Tumours are composed of different cell populations, with cancer stem-like cells being one of the most prominent examples. This specific pool of cells is thought to be responsible for cancer growth and recurrence and plays a particularly relevant role in glioblastoma (GBM), the most lethal form of primary brain tumours. Here, we have analysed the transcriptome and metabolome of an established GBM cell line (U87) and a patient-derived GBM stem-like cell line (NCH644) exposed to neurosphere or monolayer culture conditions. By integrating transcriptome and metabolome data, we identified key metabolic pathways and gene signatures that are associated with stem-like and differentiated states in GBM cells, and demonstrated that neurospheres and monolayer cells differ substantially in their metabolism and gene regulation. Furthermore, arginine biosynthesis was identified as the most significantly regulated pathway in neurospheres, although individual nodes of this pathway were distinctly regulated in the two cellular systems. Neurosphere conditions, as opposed to monolayer conditions, cause a transcriptomic and metabolic rewiring that may be crucial for the regulation of stem-like features, where arginine biosynthesis may be a key metabolic pathway. Additionally, TCGA data from GBM patients showed significant regulation of specific components of the arginine biosynthesis pathway, providing further evidence for the importance of this metabolic pathway in GBM.},
  language  = {en}
}
@article{OelschlaegelWeissSadanSalpeteretal.2020,
  author    = {Oelschlaegel, Diana and Weiss Sadan, Tommy and Salpeter, Seth and Krug, Sebastian and Blum, Galia and Schmitz, Werner and Schulze, Almut and Michl, Patrick},
  title     = {Cathepsin inhibition modulates metabolism and polarization of tumor-associated macrophages},
  series = {Cancers},
  volume    = {12},
  journal   = {Cancers},
  number    = {9},
  issn      = {2072-6694},
  doi       = {10.3390/cancers12092579},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-213040},
  year      = {2020},
  abstract  = {Stroma-infiltrating immune cells, such as tumor-associated macrophages (TAM), play an important role in regulating tumor progression and chemoresistance. These effects are mostly conveyed by secreted mediators, among them several cathepsin proteases. In addition, increasing evidence suggests that stroma-infiltrating immune cells are able to induce profound metabolic changes within the tumor microenvironment. In this study, we aimed to characterize the impact of cathepsins in maintaining the TAM phenotype in more detail. For this purpose, we investigated the molecular effects of pharmacological cathepsin inhibition on the viability and polarization of human primary macrophages as well as its metabolic consequences. Pharmacological inhibition of cathepsins B, L, and S using a novel inhibitor, GB111-NH\(_2\), led to changes in cellular recycling processes characterized by an increased expression of autophagy- and lysosome-associated marker genes and reduced adenosine triphosphate (ATP) content. Decreased cathepsin activity in primary macrophages further led to distinct changes in fatty acid metabolites associated with increased expression of key modulators of fatty acid metabolism, such as fatty acid synthase (FASN) and acid ceramidase (ASAH1). The altered fatty acid profile was associated with an increased synthesis of the pro-inflammatory prostaglandin PGE\(_2\), which correlated with the upregulation of numerous NF\(_k\)B-dependent pro-inflammatory mediators, including interleukin-1 (IL-1), interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), and tumor necrosis factor-alpha (TNFα). Our data indicate a novel link between cathepsin activity and metabolic reprogramming in macrophages, demonstrated by a profound impact on autophagy and fatty acid metabolism, which facilitates a pro-inflammatory micromilieu generally associated with enhanced tumor elimination. These results provide a strong rationale for therapeutic cathepsin inhibition to overcome the tumor-promoting effects of the immune-evasive tumor micromilieu.},
  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}
}