TY  - JOUR
A1  - Mayer, Alexander E.
A1  - Löffler, Mona C.
A1  - Loza Valdés, Angel E.
A1  - Schmitz, Werner
A1  - El-Merahbi, Rabih
A1  - Trujillo-Viera, Jonathan
A1  - Erk, Manuela
A1  - Zhang, Thianzhou
A1  - Braun, Ursula
A1  - Heikenwalder, Mathias
A1  - Leitges, Michael
A1  - Schulze, Almut
A1  - Sumara, Grzegorz
T1  - The kinase PKD3 provides negative feedback on cholesterol and triglyceride synthesis by suppressing insulin signaling
JF  - Science Signaling
N2  - 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.
KW  - Protein kinase D3 (PKD3)
KW  - cholesterol
KW  - diacylglycerol (DAG)
KW  - liver
KW  - metabolism
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250025
ET  - accepted manuscript
ER  - 
TY  - JOUR
A1  - Peixoto, Joana
A1  - Janaki-Raman, Sudha
A1  - Schlicker, Lisa
A1  - Schmitz, Werner
A1  - Walz, Susanne
A1  - Winkelkotte, Alina M.
A1  - Herold-Mende, Christel
A1  - Soares, Paula
A1  - Schulze, Almut
A1  - Lima, Jorge
T1  - Integrated metabolomics and transcriptomics analysis of monolayer and neurospheres from established glioblastoma cell lines
JF  - Cancers
N2  - 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.
KW  - glioblastoma
KW  - neurospheres
KW  - monolayer
KW  - metabolome
KW  - transcriptome
KW  - arginine metabolism
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234110
SN  - 2072-6694
VL  - 13
IS  - 6
ER  - 
TY  - JOUR
A1  - Oelschlaegel, Diana
A1  - Weiss Sadan, Tommy
A1  - Salpeter, Seth
A1  - Krug, Sebastian
A1  - Blum, Galia
A1  - Schmitz, Werner
A1  - Schulze, Almut
A1  - Michl, Patrick
T1  - Cathepsin inhibition modulates metabolism and polarization of tumor-associated macrophages
JF  - Cancers
N2  - 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.
KW  - cathepsin
KW  - activity-based probes
KW  - tumor-associated macrophage
KW  - autophagy
KW  - lysosome
KW  - lipid metabolism
KW  - inflammation
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213040
SN  - 2072-6694
VL  - 12
IS  - 9
ER  - 
TY  - JOUR
A1  - Hartmann, Oliver
A1  - Reissland, Michaela
A1  - Maier, Carina R.
A1  - Fischer, Thomas
A1  - Prieto-Garcia, Cristian
A1  - Baluapuri, Apoorva
A1  - Schwarz, Jessica
A1  - Schmitz, Werner
A1  - Garrido-Rodriguez, Martin
A1  - Pahor, Nikolett
A1  - Davies, Clare C.
A1  - Bassermann, Florian
A1  - Orian, Amir
A1  - Wolf, Elmar
A1  - Schulze, Almut
A1  - Calzado, Marco A.
A1  - Rosenfeldt, Mathias T.
A1  - Diefenbacher, Markus E.
T1  - Implementation of CRISPR/Cas9 Genome Editing to Generate Murine Lung Cancer Models That Depict the Mutational Landscape of Human Disease
JF  - Frontiers in Cell and Developmental Biology
N2  - Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in both men and women. Despite the development of novel therapeutic interventions, the 5-year survival rate for non-small cell lung cancer (NSCLC) patients remains low, demonstrating the necessity for novel treatments. One strategy to improve translational research is the development of surrogate models reflecting somatic mutations identified in lung cancer patients as these impact treatment responses. With the advent of CRISPR-mediated genome editing, gene deletion as well as site-directed integration of point mutations enabled us to model human malignancies in more detail than ever before. Here, we report that by using CRISPR/Cas9-mediated targeting of Trp53 and KRas, we recapitulated the classic murine NSCLC model Trp53fl/fl:lsl-KRasG12D/wt. Developing tumors were indistinguishable from Trp53fl/fl:lsl-KRasG12D/wt-derived tumors with regard to morphology, marker expression, and transcriptional profiles. We demonstrate the applicability of CRISPR for tumor modeling in vivo and ameliorating the need to use conventional genetically engineered mouse models. Furthermore, tumor onset was not only achieved in constitutive Cas9 expression but also in wild-type animals via infection of lung epithelial cells with two discrete AAVs encoding different parts of the CRISPR machinery. While conventional mouse models require extensive husbandry to integrate new genetic features allowing for gene targeting, basic molecular methods suffice to inflict the desired genetic alterations in vivo. Utilizing the CRISPR toolbox, in vivo cancer research and modeling is rapidly evolving and enables researchers to swiftly develop new, clinically relevant surrogate models for translational research.
KW  - non-small cell lung cancer
KW  - CRISPR-Cas9
KW  - mouse model
KW  - lung cancer
KW  - MYC
KW  - JUN
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230949
SN  - 2296-634X
VL  - 9
ER  - 
TY  - JOUR
A1  - Vollmuth, Nadine
A1  - Schlicker, Lisa
A1  - Guo, Yongxia
A1  - Hovhannisyan, Pargev
A1  - Janaki-Raman, Sudha
A1  - Kurmasheva, Naziia
A1  - Schmitz, Werner
A1  - Schulze, Almut
A1  - Stelzner, Kathrin
A1  - Rajeeve, Karthika
A1  - Rudel, Thomas
T1  - c-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis
JF  - eLife
N2  - 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.
KW  - Chlamydia trachomatis
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301385
VL  - 11
ER  -