@article{vonLoeffelholzLieskeNeuschaeferRubeetal.2017, author = {von Loeffelholz, Christian and Lieske, Stefanie and Neuschaefer-Rube, Frank and Willmes, Diana M. and Raschzok, Nathanael and Sauer, Igor M. and K{\"o}nig, J{\"o}rg and Fromm, Martin F. and Horn, Paul and Chatzigeorgiou, Antonios and Pathe-Neuschaefer-Rube, Andrea and Jordan, Jens and Pfeiffer, Andreas F. H. and Mingrone, Geltrude and Bornstein, Stefan R. and Stroehle, Peter and Harms, Christoph and Wunderlich, F. Thomas and Helfand, Stephen L. and Bernier, Michel and de Cabo, Rafael and Shulman, Gerald I. and Chavakis, Triantafyllos and P{\"u}schel, Gerhard Paul and Birkenfeld, Andreas L.}, title = {The human longevity gene homolog INDY and interleukin-6 interact in hepatic lipid metabolism}, series = {Hepatology}, volume = {66}, journal = {Hepatology}, number = {2}, publisher = {Wiley}, address = {Hoboken}, issn = {0270-9139}, doi = {10.1002/hep.29089}, pages = {616 -- 630}, year = {2017}, abstract = {Reduced expression of the Indy ("I am Not Dead, Yet") gene in lower organisms promotes longevity in a manner akin to caloric restriction. Deletion of the mammalian homolog of Indy (mIndy, Slc13a5) encoding for a plasma membrane-associated citrate transporter expressed highly in the liver, protects mice from high-fat diet-induced and aging-induced obesity and hepatic fat accumulation through a mechanism resembling caloric restriction. We studied a possible role of mIndy in human hepatic fat metabolism. In obese, insulin-resistant patients with nonalcoholic fatty liver disease, hepatic mIndy expression was increased and mIndy expression was also independently associated with hepatic steatosis. In nonhuman primates, a 2-year high-fat, high-sucrose diet increased hepatic mIndy expression. Liver microarray analysis showed that high mIndy expression was associated with pathways involved in hepatic lipid metabolism and immunological processes. Interleukin-6 (IL-6) was identified as a regulator of mIndy by binding to its cognate receptor. Studies in human primary hepatocytes confirmed that IL-6 markedly induced mIndy transcription through the IL-6 receptor and activation of the transcription factor signal transducer and activator of transcription 3, and a putative start site of the human mIndy promoter was determined. Activation of the IL-6-signal transducer and activator of transcription 3 pathway stimulated mIndy expression, enhanced cytoplasmic citrate influx, and augmented hepatic lipogenesis in vivo. In contrast, deletion of mIndy completely prevented the stimulating effect of IL-6 on citrate uptake and reduced hepatic lipogenesis. These data show that mIndy is increased in liver of obese humans and nonhuman primates with NALFD. Moreover, our data identify mIndy as a target gene of IL-6 and determine novel functions of IL-6 through mINDY. Conclusion: Targeting human mINDY may have therapeutic potential in obese patients with nonalcoholic fatty liver disease. German Clinical Trials Register: DRKS00005450.}, language = {en} } @article{PatheNeuschaeferRubeNeuschaeferRubeGenzetal.2015, author = {Pathe-Neuschaefer-Rube, Andrea and Neuschaefer-Rube, Frank and Genz, Lara and P{\"u}schel, Gerhard Paul}, title = {Botulinum Neurotoxin Dose-Dependently Inhibits Release of Neurosecretory Vesicle-Targeted Luciferase from Neuronal Cells}, series = {Alternatives to animal experimentation : ALTEX ; a journal for new paths in biomedical science}, volume = {32}, journal = {Alternatives to animal experimentation : ALTEX ; a journal for new paths in biomedical science}, number = {4}, publisher = {Springer}, address = {Heidelberg}, issn = {1868-596X}, pages = {297 -- 306}, year = {2015}, abstract = {Botulinum toxin is a bacterial toxin that inhibits neurotransmitter release from neurons and thereby causes a flaccid paralysis. It is used as drug to treat a number of serious ailments and, more frequently, for aesthetic medical interventions. Botulinum toxin for pharmacological applications is isolated from bacterial cultures. Due to partial denaturation of the protein, the specific activity of these preparations shows large variations. Because of its extreme potential toxicity, pharmacological preparations must be carefully tested for their activity. For the current gold standard, the mouse lethality assay, several hundred thousand mice are killed per year. Alternative methods have been developed that suffer from one or more of the following deficits: In vitro enzyme assays test only the activity of the catalytic subunit of the toxin. Enzymatic and cell based immunological assays are specific for just one of the different serotypes. The current study takes a completely different approach that overcomes these limitations: Neuronal cell lines were stably transfected with plasmids coding for luciferases of different species, which were N-terminally tagged with leader sequences that redirect the luciferase into neuro-secretory vesicles. From these vesicles, luciferases were released upon depolarization of the cells. The depolarization-dependent release was efficiently inhibited by botulinum toxin in a concentration range (1 to 100 pM) that is used in pharmacological preparations. The new assay might thus be an alternative to the mouse lethality assay and the immunological assays already in use.}, language = {en} } @article{NeuschaeferRubeSchraplauScheweetal.2015, author = {Neuschaefer-Rube, Frank and Schraplau, Anne and Schewe, Bettina and Lieske, Stefanie and Kruetzfeldt, Julia-Mignon and Ringel, Sebastian and Henkela, Janin and Birkenfeld, Andreas L. and P{\"u}schel, Gerhard Paul}, title = {Arylhydrocarbon receptor-dependent mIndy (SIc13a5) induction as possible contributor to benzo[a]pyrene-induced lipid accumulation in hepatocytes}, series = {Toxicology}, volume = {337}, journal = {Toxicology}, publisher = {Elsevier}, address = {Clare}, issn = {0300-483X}, doi = {10.1016/j.tox.2015.08.007}, pages = {1 -- 9}, year = {2015}, abstract = {Non-alcoholic fatty liver disease is a growing problem in industrialized and developing countries. Hepatic lipid accumulation is the result of an imbalance between fatty acid uptake, fatty acid de novo synthesis, beta-oxidation and secretion of triglyceride-rich lipoproteins from the hepatocyte. A central regulator of hepatic lipid metabolism is cytosolic citrate that can either be derived from the mitochondrium or be taken up from the blood via the plasma membrane sodium citrate transporter NaCT, the product of the mammalian INDY gene (SLC13A5). mINDY ablation protects against diet-induced steatosis whereas mINDY expression is increased in patients with hepatic steatosis. Diet-induced hepatic steatosis is also enhanced by activation of the arylhyrocarbon receptor (AhR) both in humans and animal models. Therefore, the hypothesis was tested whether the mINDY gene might be a target of the AhR. In accordance with such a hypothesis, the AhR activator benzo[a]pyrene induced the mINDY expression in primary cultures of rat hepatocytes in an AhR-dependent manner. This induction resulted in an increased citrate uptake and citrate incorporation into lipids which probably was further enhanced by the benzo[a]pyrene-dependent induction of key enzymes of fatty acid synthesis. A potential AhR binding site was identified in the mINDY promoter that appears to be conserved in the human promoter. Elimination or mutation of this site largely abolished the activation of the mINDY promoter by benzo[a]pyrene. This study thus identified the mINDY as an AhR target gene. AhR-dependent induction of the mINDY gene might contribute to the development of hepatic steatosis. (C) 2015 Elsevier Ireland Ltd. All rights reserved.}, language = {en} } @article{NeuschaeferRubeLieskeKunaetal.2014, author = {Neuschaefer-Rube, Frank and Lieske, Stefanie and Kuna, Manuela and Henkel, Janin and Perry, Rachel J. and Erion, Derek M. and Pesta, Dominik and Willmes, Diana M. and Brachs, Sebastian and von Loeffelholz, Christian and Tolkachov, Alexander and Schupp, Michael and Pathe-Neuschaefer-Rube, Andrea and Pfeiffer, Andreas F. H. and Shulman, Gerald I. and P{\"u}schel, Gerhard Paul and Birkenfeld, Andreas L.}, title = {The mammalian INDY homolog is induced by CREB in a rat model of type 2 diabetes}, series = {Diabetes : a journal of the American Diabetes Association}, volume = {63}, journal = {Diabetes : a journal of the American Diabetes Association}, number = {3}, publisher = {American Diabetes Association}, address = {Alexandria}, issn = {0012-1797}, pages = {1048 -- 1057}, year = {2014}, language = {en} } @article{WienekeNeuschaeferRubeBodeetal.2009, author = {Wieneke, Nadine and Neuschaefer-Rube, Frank and Bode, L. M. and Kuna, Manuela and Andres, Jesus and Carnevali Junior, Luiz Carlos and Hirsch-Ernst, Karen I. and P{\"u}schel, Gerhard Paul}, title = {Synergistic acceleration of thyroid hormone degradation by phenobarbital and the PPAR alpha agonist WY14643 in rat hepatocytes}, issn = {0041-008X}, doi = {10.1016/j.taap.2009.07.014}, year = {2009}, abstract = {Energy balance is maintained by controlling both energy intake and energy expenditure. Thyroid hormones play a crucial role in regulating energy expenditure. Their levels are adjusted by a tight feed back-control led regulation of thyroid hormone production/incretion and by their hepatic metabolism. Thyroid hormone degradation has previously been shown to be enhanced by treatment with phenobarbital or other antiepileptic drugs due to a CAR-dependent induction of phase 11 enzymes of xenobiotic metabolism. We have recently shown, that PPAR alpha agonists synergize with phenobarbital to induce another prototypical CAR target gene, CYP2B1. Therefore, it was tested whether a PPAR alpha agonist could enhance the phenobarbital-dependent acceleration of thyroid hormone elimination. In primary cultures of rat hepatocytes the apparent half-life of T3 was reduced after induction with a combination of phenobarbital and the PPARa agonist WY14643 to a larger extent than after induction with either Compound alone. The synergistic reduction of the half-life could be attributed to a synergistic induction of CAR and the CAR target genes that code for enzymes and transporters involved in the hepatic elimination of T3, such as OATP1A1, OATP1A3, UGT1A3 and UCT1A10. The PPAR alpha-dependent CAR induction and the subsequent induction of T3-eliminating enzymes might be of physiological significance for the fasting- incluced reduction in energy expenditure by fatty acids as natural PPARa ligands. The synergism of the PPAR alpha agonist WY14643 and phenobarbital in inducing thyroid hormone breakdown might serve as a paradigm for the synergistic disruption of endocrine control by other combinations of xenobiotics.}, language = {en} } @article{HenkelNeuschaeferRubePatheNeuschaeferRubeetal.2009, author = {Henkel, Janin and Neuschaefer-Rube, Frank and Pathe-Neuschaefer-Rube, Andrea and P{\"u}schel, Gerhard Paul}, title = {Aggravation by prostaglandin e-2 of interleukin-6-dependent insulin resistance in hepatocytes}, issn = {0270-9139}, doi = {10.1002/Hep.23064}, year = {2009}, abstract = {Hepatic insulin resistance is a major contributor to fasting hyperglycemia in patients with metabolic syndrome and type 2 diabetes. Circumstantial evidence suggests that cyclooxygenase products in addition to cytokines might contribute to insulin resistance. However, direct evidence for a role of prostaglandins in the development of hepatic insulin resistance is lacking. Therefore, the impact of prostaglandin E-2 (PGE(2)) alone and in combination with interleukin-6 (IL-6) on insulin signaling was studied in primary hepatocyte cultures. Rat hepatocytes were incubated with IL-6 and/or PGE(2) and subsequently with insulin. Glycogen synthesis was monitored by radiochemical analysis; the activation state of proteins of the insulin receptor signal chain was analyzed by western blot with phosphospecific antibodies. In hepatocytes, insulin-stimulated glycogen synthesis and insulin-dependent phosphorylation of Akt-kinase were attenuated synergistically by prior incubation with IL-6 and/or PGE(2) while insulin receptor autophosphorylation was barely affected. IL-6 but not PGE(2) induced suppressors of cytokine signaling (SOCS3). PGE(2) but not IL-6 activated extracellular signal-regulated kinase 1/2 (ERK1/2) persistently. Inhibition of ERK1/2 activation by PD98059 abolished the PGE(2)-dependent but not the IL-6-dependent attenuation of insulin signaling. In HepG2 cells expressing a recombinant EP3-receptor, PGE(2) pre-incubation activated ERK1/2, caused a serine phosphorylation of insulin receptor substrate 1 (IRS1), and reduced the insulin-dependent Akt-phosphorylation. Conclusion: PGE(2) might contribute to hepatic insulin resistance via an EP3-receptor-dependent ERK1/2 activation resulting in a serine phosphorylation of insulin receptor substrate, thereby preventing an insulin-dependent activation of Akt and glycogen synthesis. Since different molecular mechanisms appear to be employed, PGE(2) may synergize with IL-6, which interrupted the insulin receptor signal chain, principally by an induction of SOCS, namely SOCS3.}, language = {en} }