TY  - JOUR
A1  - Lambour, Benjamin
A1  - Glenz, René
A1  - Forner, Carmen
A1  - Krischke, Markus
A1  - Mueller, Martin J.
A1  - Fekete, Agnes
A1  - Waller, Frank
T1  - Sphingolipid long-chain base phosphate degradation can be a rate-limiting step in long-chain base homeostasis
JF  - Frontiers in Plant Science
N2  - Sphingolipid long-chain bases (LCBs) are building blocks for membrane-localized sphingolipids, and are involved in signal transduction pathways in plants. Elevated LCB levels are associated with the induction of programmed cell death and pathogen-derived toxin-induced cell death. Therefore, levels of free LCBs can determine survival of plant cells. To elucidate the contribution of metabolic pathways regulating high LCB levels, we applied the deuterium-labeled LCB D-erythro-sphinganine-d7 (D7-d18:0), the first LCB in sphingolipid biosynthesis, to Arabidopsis leaves and quantified labeled LCBs, LCB phosphates (LCB-Ps), and 14 abundant ceramide (Cer) species over time. We show that LCB D7-d18:0 is rapidly converted into the LCBs d18:0P, t18:0, and t18:0P. Deuterium-labeled ceramides were less abundant, but increased over time, with the highest levels detected for Cer(d18:0/16:0), Cer(d18:0/24:0), Cer(t18:0/16:0), and Cer(t18:0/22:0). A more than 50-fold increase of LCB-P levels after leaf incubation in LCB D7-d18:0 indicated that degradation of LCBs via LCB-Ps is important, and we hypothesized that LCB-P degradation could be a rate-limiting step to reduce high levels of LCBs. To functionally test this hypothesis, we constructed a transgenic line with dihydrosphingosine-1-phosphate lyase 1 (DPL1) under control of an inducible promotor. Higher expression of DPL1 significantly reduced elevated LCB-P and LCB levels induced by Fumonisin B1, and rendered plants more resistant against this fungal toxin. Taken together, we provide quantitative data on the contribution of major enzymatic pathways to reduce high LCB levels, which can trigger cell death. Specifically, we provide functional evidence that DPL1 can be a rate-limiting step in regulating high LCB levels.
KW  - sphingolipid
KW  - long-chain base
KW  - plant sphingolipid metabolism
KW  - cell death
KW  - metabolic flux analysis
KW  - dihydrosphingosine-1-phosphate lyase
KW  - LC–MS/MS
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-277679
SN  - 1664-462X
VL  - 13
ER  - 
TY  - JOUR
A1  - Alepee, Natalie
A1  - Bahinski, Anthony
A1  - Daneshian, Mardas
A1  - De Weyer, Bart
A1  - Fritsche, Ellen
A1  - Goldberg, Alan
A1  - Hansmann, Jan
A1  - Hartung, Thomas
A1  - Haycock, John
A1  - Hogberg, Helena T.
A1  - Hoelting, Lisa
A1  - Kelm, Jens M.
A1  - Kadereit, Suzanne
A1  - McVey, Emily
A1  - Landsiedel, Robert
A1  - Leist, Marcel
A1  - Lübberstedt, Marc
A1  - Noor, Fozia
A1  - Pellevoisin, Christian
A1  - Petersohn, Dirk
A1  - Pfannenbecker, Uwe
A1  - Reisinger, Kerstin
A1  - Ramirez, Tzutzuy
A1  - Rothen-Rutishauser, Barbara
A1  - Schäfer-Korting, Monika
A1  - Zeilinger, Katrin
A1  - Zurich, Marie-Gabriele
T1  - State-of-the-Art of 3D Cultures (Organs-on-a-Chip) in Safety Testing and Pathophysiology
JF  - ALTEX - Alternatives to Animal Experimentation
N2  - Integrated approaches using different in vitro methods in combination with bioinformatics can (i) increase the success rate and speed of drug development; (ii) improve the accuracy of toxicological risk assessment; and (iii) increase our understanding of disease. Three-dimensional (3D) cell culture models are important building blocks of this strategy which has emerged during the last years. The majority of these models are organotypic, i.e., they aim to reproduce major functions of an organ or organ system. This implies in many cases that more than one cell type forms the 3D structure, and often matrix elements play an important role. This review summarizes the state of the art concerning commonalities of the different models. For instance, the theory of mass transport/metabolite exchange in 3D systems and the special analytical requirements for test endpoints in organotypic cultures are discussed in detail. In the next part, 3D model systems for selected organs liver, lung, skin, brain are presented and characterized in dedicated chapters. Also, 3D approaches to the modeling of tumors are presented and discussed. All chapters give a historical background, illustrate the large variety of approaches, and highlight up- and downsides as well as specific requirements. Moreover, they refer to the application in disease modeling, drug discovery and safety assessment. Finally, consensus recommendations indicate a roadmap for the successful implementation of 3D models in routine screening. It is expected that the use of such models will accelerate progress by reducing error rates and wrong predictions from compound testing.
KW  - 3D models
KW  - organotypic
KW  - organ-on-a-chip
KW  - multicellular tumor spheroids
KW  - primary human hepatocytes
KW  - embryonic stem cell
KW  - reconstructed human epidermis
KW  - in-vitro models
KW  - full thickness skin
KW  - necrosis-factor-alpha
KW  - metabolic flux analysis
KW  - long-term
KW  - human liver cells
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117826
VL  - 31
IS  - 4
ER  -