Publications by authors named "Susanne Trappe"

5 Publications

  • Page 1 of 1

The Combined Influence of Magnesium and Insulin on Central Metabolic Functions and Expression of Genes Involved in Magnesium Homeostasis of Cultured Bovine Adipocytes.

Int J Mol Sci 2021 May 31;22(11). Epub 2021 May 31.

Institute of Veterinary Physiology, Freie Universität Berlin, 14163 Berlin, Germany.

At the onset of lactation, dairy cows suffer from insulin resistance, insulin deficiency or both, similar to human diabetes, resulting in lipolysis, ketosis and fatty liver. This work explored the combined effects of different levels of magnesium (0.1, 0.3, 1 and 3 mM) and insulin (25, 250 and 25,000 pM) on metabolic pathways and the expression of magnesium-responsive genes in a bovine adipocyte model. Magnesium starvation (0.1 mM) and low insulin (25 pM) independently decreased or tended to decrease the accumulation of non-polar lipids and uptake of the glucose analog 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-6-deoxyglucose (6-NBDG). Activity of glycerol 3-phosphate dehydrogenase (GPDH) was highest at 25 pM insulin and 3 mM magnesium. Expression of and was reduced at 0.1 mM magnesium either across insulin concentrations () or at 250 pM insulin (). expression was reduced at 3 mM magnesium. expression was reduced at 3 mM and 0.1 mM magnesium at 25 and 250 pM insulin, respectively. Expression of , , and was not affected. We conclude that magnesium promotes lipogenesis in adipocytes and inversely regulates the transcription of genes that increase vs. decrease cytosolic magnesium concentration. The induction of GAPDH activity by surplus magnesium at low insulin concentration can counteract excessive lipomobilization.
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http://dx.doi.org/10.3390/ijms22115897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8199494PMC
May 2021

Optimizing adipogenic transdifferentiation of bovine mesenchymal stem cells: a prominent role of ascorbic acid in induction.

Adipocyte 2020 12;9(1):35-50

Institute of Veterinary-Physiology, Freie Universität Berlin, Berlin, Germany.

Adipocyte differentiation of bovine adipose-derived stem cells (ASC) was induced by foetal bovine serum (FBS), biotin, pantothenic acid, insulin, rosiglitazone, dexamethasone and 3-isobutyl-1-methylxanthine, followed by incubation in different media to test the influence of ascorbic acid (AsA), bovine serum lipids (BSL), FBS, glucose and acetic acid on transdifferentiation into functional adipocytes. Moreover, different culture plate coatings (collagen-A, gelatin-A or poly-L-lysine) were tested. The differentiated ASC were subjected to Nile red staining, DAPI staining, immunocytochemistry and quantitative reverse transcription PCR (for ). Nile red quantification showed a significant increase in the development of lipid droplets in treatments with AsA and BSL without FBS. The presence of BSL induced a prominent increase in mRNA abundance and in FABP4 immunofluorescence signals in coincubation with AsA. The abundance of and mRNA decreased or tended to decrease in the absence of FBS, and ENG was additionally suppressed by AsA. DAPI fluorescence was higher in cells cultured in poly-L-lysine or gelatin-A coated wells. In additional experiments, the multi-lineage differentiation potential to osteoblasts was verified in medium containing ß-glycerophosphate, dexamethasone and 1,25-dihydroxyvitamin D using alizarin red staining. In conclusion, bovine ASC are capable of multi-lineage differentiation. Poly-L-lysine or gelatin-A coating, the absence of FBS, and the presence of BSL and AsA favour optimal transdifferentiation into adipocytes. AsA supports transdifferentiation via a unique role in induction, but this is not linearly related to the primarily BSL-driven lipid accumulation.: AcA: acetic acid; AsA: ascorbic acid; ASC: adipose-derived stem cells; BSL: bovine serum lipids; DAPI: 4´,6-diamidino-2-phenylindole; DLK: delta like non-canonical notch ligand; DMEM: Dulbecco's modified Eagle's medium; DPBS: Dulbecco's phosphate-buffered saline; ENG: endoglin; FABP: fatty acid binding protein; FAS: fatty acid synthase; GLUT4: glucose transporter type 4; IBMX: 3-isobutyl-1-methylxanthine; LPL: lipoprotein lipase; MSC: mesenchymal stem cells; α-MEM: α minimum essential medium; NT5E: ecto-5'-nucleotidase; PDGFRα: platelet derived growth factor receptor α; PPAR: peroxisome proliferator activated receptor γ; RPS19: ribosomal protein S19; SEM: standard error of the mean; THY1: Thy-1 cell surface antigen; TRT: treatment; TRT-Con: treatment negative control; YWHAZ: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta.
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http://dx.doi.org/10.1080/21623945.2020.1720480DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6999845PMC
December 2020

Influence of Bovine Serum Lipids and Fetal Bovine Serum on the Expression of Cell Surface Markers in Cultured Bovine Preadipocytes.

Cells Tissues Organs 2017 12;204(1):13-24. Epub 2017 May 12.

Institute of Veterinary Physiology, Free University of Berlin, Berlin, Germany.

To establish the influence of fetal bovine serum (FBS) and bovine serum lipids (BSL) on cell differentiation marker expression, bovine adipose-derived stem cells from subcutaneous tissue were incubated for 14 days in 4 types of differentiation media containing 10% FBS and 10 µL/mL BSL (TRT-1), no FBS and 10 µL/mL of BSL (TRT-2), 10% FBS and no BSL (TRT-3), or no supplements (TRT-4). Cells were subjected to Nile red staining, immunocytochemistry (CD73, CD90, CD105, DLK1, FabP4), and quantitative real-time PCR (CD73, CD90, CD105, FabP4). The number of cells presenting FabP4 and the percentage of mature adipocytes with large lipid droplets were increased in TRT-2, accompanied by a robust increase in FabP4 mRNA abundance and a decrease in DLK1-positive cells. In preadipocytes, CD73 was present around the nucleus and translocated towards cell membranes during differentiation. Although the percentage of CD73-positive cells was not different among treatments, its mRNA abundance, immunocytochemical staining intensity, and translocation towards cell membranes were decreased when the medium contained no FBS (TRT-2 and TRT-4). All cells showed a diffuse distribution of CD90 and CD105 and remained positive for these markers irrespective of the treatment. However, the CD90 and CD105 mRNA abundance was decreased in TRT-2 and TRT-4; i.e., in media containing no FBS. The presence of FBS increased the absolute number of cell nuclei as assessed by DAPI fluorescence. Our results suggest that bovine subcutaneous preadipocytes display typical stem cell markers. The differentiation into mature adipocytes is promoted by BSL, whereas FBS endorses cell proliferation.
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http://dx.doi.org/10.1159/000472708DOI Listing
March 2018

Metabolically competent human skin models: activation and genotoxicity of benzo[a]pyrene.

Toxicol Sci 2013 Feb 11;131(2):351-9. Epub 2012 Nov 11.

German Federal Institute for Risk Assessment (BfR), Department of Product Safety, 10589 Berlin, Germany.

The polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BP) is metabolized into a complex pattern of BP derivatives, among which the ultimate carcinogen (+)-anti-BP-7,8-diol-9,10-epoxide (BPDE) is formed to certain extents. Skin is frequently in contact with PAHs and data on the metabolic capacity of skin tissue toward these compounds are inconclusive. We compared BP metabolism in excised human skin, commercially available in vitro 3D skin models and primary 2D skin cell cultures, and analyzed the metabolically catalyzed occurrence of seven different BP follow-up products by means of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All models investigated were competent to metabolize BP, and the metabolic profiles generated by ex vivo human skin and skin models were remarkably similar. Furthermore, the genotoxicity of BP and its derivatives was monitored in these models via comet assays. In a full-thickness skin, equivalent BP-mediated genotoxic stress was generated via keratinocytes. Cultured primary keratinocytes revealed a level of genotoxicity comparable with that of direct exposure to 50-100 nM of BPDE. Our data demonstrate that the metabolic capacity of human skin ex vivo, as well as organotypic human 3D skin models toward BP, is sufficient to cause significant genotoxic stress and thus cutaneous bioactivation may potentially contribute to mutations that ultimately lead to skin cancer.
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http://dx.doi.org/10.1093/toxsci/kfs316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551429PMC
February 2013

Renaturation and purification of bone morphogenetic protein-2 produced as inclusion bodies in high-cell-density cultures of recombinant Escherichia coli.

J Biotechnol 2002 Mar;94(2):185-94

Biochemical Engineering Division, National Research Center for Biotechnology (GBF), Mascheroder Weg 1, 38124, Braunschweig, Germany.

Eschericha coli was genetically engineered to produce recombinant human bone morphogenetic protein-2 (rhBMP-2) in a non-active aggregated form using a temperature-inducible expression system. High concentrations of both biomass (75 g cell dry weight per liter of culture broth) and inactive rhBMP-2 (8.6 gl(-1)) were obtained by applying a high-cell-density cultivation procedure. After washing and solubilizing the inclusion bodies, rhBMP-2 was refolded and dimerized at concentrations up to 100 mgl(-1) by means of a simple dilution method with yields exceeding 50%. Finally, a one-step purification procedure based on affinity chromatography was implemented to isolate the rhBMP-2 dimer. With the established renaturation and purification protocols, yields of more than 10 mg rhBMP-2 dimer per gram cell dry weight were obtained corresponding to 750 mg rhBMP-2 dimer per liter of culture broth. The purified rhBMP-2 dimer showed biological activity equivalent to CHO produced rhBMP-2 as tested by the induction of alkaline phosphatase activity in C2C12 cells.
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http://dx.doi.org/10.1016/s0168-1656(01)00425-4DOI Listing
March 2002
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