TY - JOUR A1 - Laeger, Thomas A1 - Castano-Martinez, Teresa A1 - Werno, Martin W. A1 - Japtok, Lukasz A1 - Baumeier, Christian A1 - Jonas, Wenke A1 - Kleuser, Burkhard A1 - Schürmann, Annette T1 - Dietary carbohydrates impair the protective effect of protein restriction against diabetes in NZO mice used as a model of type 2 diabetes JF - Diabetologia : journal of the European Association for the Study of Diabetes (EASD) N2 - Aims/hypothesis Low-protein diets are well known to improve glucose tolerance and increase energy expenditure. Increases in circulating fibroblast growth factor 21 (FGF21) have been implicated as a potential underlying mechanism. Methods We aimed to test whether low-protein diets in the context of a high-carbohydrate or high-fat regimen would also protect against type 2 diabetes in New Zealand Obese (NZO) mice used as a model of polygenetic obesity and type 2 diabetes. Mice were placed on high-fat diets that provided protein at control (16 kJ%; CON) or low (4 kJ%; low-protein/high-carbohydrate [LP/HC] or low-protein/high-fat [LP/HF]) levels. Results Protein restriction prevented the onset of hyperglycaemia and beta cell loss despite increased food intake and fat mass. The effect was seen only under conditions of a lower carbohydrate/fat ratio (LP/HF). When the carbohydrate/fat ratio was high (LP/HC), mice developed type 2 diabetes despite the robustly elevated hepatic FGF21 secretion and increased energy expenditure. Conclusion/interpretation Prevention of type 2 diabetes through protein restriction, without lowering food intake and body fat mass, is compromised by high dietary carbohydrates. Increased FGF21 levels and elevated energy expenditure do not protect against hyperglycaemia and type 2 diabetes per se. KW - Energy expenditure KW - FGF21 KW - Hyperglycaemia KW - Insulin resistance KW - NZO KW - Obesity KW - Protein restriction Y1 - 2018 U6 - https://doi.org/10.1007/s00125-018-4595-1 SN - 0012-186X SN - 1432-0428 VL - 61 IS - 6 SP - 1459 EP - 1469 PB - Springer CY - New York ER - TY - JOUR A1 - Reichel, Martin A1 - Rhein, Cosima A1 - Hofmann, Lena M. A1 - Monti, Juliana A1 - Japtok, Lukasz A1 - Langgartner, Dominik A1 - Füchsl, Andrea M. A1 - Kleuser, Burkhard A1 - Gulbins, Erich A1 - Hellerbrand, Claus A1 - Reber, Stefan O. A1 - Kornhuber, Johannes T1 - Chronic Psychosocial Stress in Mice Is Associated With Increased Acid Sphingomyelinase Activity in Liver and Serum and With Hepatic C16:0-Ceramide Accumulation JF - Frontiers in Psychiatry N2 - Chronic psychosocial stress adversely affects human morbidity and is a risk factor for inflammatory disorders, liver diseases, obesity, metabolic syndrome, and major depressive disorder (MDD). In recent studies, we found an association of MDD with an increase of acid sphingomyelinase (ASM) activity. Thus, we asked whether chronic psychosocial stress as a detrimental factor contributing to the emergence of MDD would also affect ASM activity and sphingolipid (SL) metabolism. To induce chronic psychosocial stress in male mice we employed the chronic subordinate colony housing (CSC) paradigm and compared them to non-stressed single housed control (SHC) mice. We determined Asm activity in liver and serum, hepatic SL concentrations as well as hepatic mRNA expression of genes involved in SL metabolism. We found that hepatic Asm activity was increased by 28% (P = 0.006) and secretory Asm activity by 47% (P = 0.002) in stressed mice. C16:0-Cer was increased by 40% (P = 0.008). Gene expression analysis further revealed an increased expression of tumor necrosis factor (TNF)-alpha (P = 0.009) and of several genes involved in SL metabolism (Cers5, P = 0.028; Cers6, P = 0.045; Gba, P = 0.049; Gba2, P = 0.030; Ormdl2, P = 0.034; Smpdl3B; P = 0.013). Our data thus provides first evidence that chronic psychosocial stress, at least in mice, induces alterations in SL metabolism, which in turn might be involved in mediating the adverse health effects of chronic psychosocial stress and peripheral changes occurring in mood disorders. KW - chronic psychosocial stress KW - acid sphingomyelinase KW - ceramide KW - sphingolipid metabolism KW - chronic subordinate colony housing (CSC) KW - liver metabolism Y1 - 2018 U6 - https://doi.org/10.3389/fpsyt.2018.00496 SN - 1664-0640 VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Plöhn, Svenja A1 - Edelmann, Bärbel A1 - Japtok, Lukasz A1 - He, Xingxuan A1 - Hose, Matthias A1 - Hansen, Wiebke A1 - Schuchman, Edward H. A1 - Eckstein, Anja A1 - Berchner-Pfannschmidt, Utta T1 - CD40 enhances sphingolipids in orbital fibroblasts BT - potential role of sphingosine-1-phosphate in inflammatory T-Cell migration in graves' orbitopathy JF - Investigative ophthalmology & visual science N2 - METHODS. OFs and T cells were derived from GO patients and healthy control (Ctl) persons. S1P abundance in orbital tissues was evaluated by immunofluorescence. OFs were stimulated with CD40 ligand and S1P levels were determined by ELISA. Further, activities of acid sphingomyelinase (ASM), acid ceramidase, and sphingosine kinase were measured by ultraperformance liquid chromatography. Sphingosine and ceramide contents were analyzed by mass spectrometry. Finally, the role for S1P in T-cell attraction was investigated by T-cell migration assays. RESULTS. GO orbital tissue showed elevated amounts of S1P as compared to control samples. Stimulation of CD40 induced S1P expression in GO-derived OFs, while Ctl-OFs remained unaffected. A significant increase of ASM and sphingosine kinase activities, as well as lipid formation, was observed in GO-derived OFs. Migration assay of T cells in the presence of SphK inhibitor revealed that S1P released by GO-OFs attracted T cells for migration. CONCLUSIONS. The results demonstrated that CD40 ligand stimulates GO fibroblast to produce S1P, which is a driving force for T-cell migration. The results support the use of S1P receptor signaling modulators in GO management. KW - inflammation Y1 - 2018 U6 - https://doi.org/10.1167/iovs.18-25466 SN - 0146-0404 SN - 1552-5783 VL - 59 IS - 13 SP - 5391 EP - 5397 PB - Association for Research in Vision and Opthalmology CY - Rockville ER -