@article{KressJessenHufnageletal.2023, author = {Kreß, Julia Katharina Charlotte and Jessen, Christina and Hufnagel, Anita and Schmitz, Werner and Da Xavier Silva, Thamara Nishida and Ferreira Dos Santos, Anc{\´e}ly and Mosteo, Laura and Goding, Colin R. and Friedmann Angeli, Jos{\´e} Pedro and Meierjohann, Svenja}, title = {The integrated stress response effector ATF4 is an obligatory metabolic activator of NRF2}, series = {Cell Reports}, volume = {42}, journal = {Cell Reports}, number = {7}, doi = {10.1016/j.celrep.2023.112724}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350312}, year = {2023}, abstract = {Highlights • The integrated stress response leads to a general ATF4-dependent activation of NRF2 • ATF4 causes a CHAC1-dependent GSH depletion, resulting in NRF2 stabilization • An elevation of NRF2 transcript levels fosters this effect • NRF2 supports the ISR/ATF4 pathway by improving cystine and antioxidant supply Summary The redox regulator NRF2 becomes activated upon oxidative and electrophilic stress and orchestrates a response program associated with redox regulation, metabolism, tumor therapy resistance, and immune suppression. Here, we describe an unrecognized link between the integrated stress response (ISR) and NRF2 mediated by the ISR effector ATF4. The ISR is commonly activated after starvation or ER stress and plays a central role in tissue homeostasis and cancer plasticity. ATF4 increases NRF2 transcription and induces the glutathione-degrading enzyme CHAC1, which we now show to be critically important for maintaining NRF2 activation. In-depth analyses reveal that NRF2 supports ATF4-induced cells by increasing cystine uptake via the glutamate-cystine antiporter xCT. In addition, NRF2 upregulates genes mediating thioredoxin usage and regeneration, thus balancing the glutathione decrease. In conclusion, we demonstrate that the NRF2 response serves as second layer of the ISR, an observation highly relevant for the understanding of cellular resilience in health and disease.}, 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{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} }