24 results on '"Künstle, Gerald"'
Search Results
2. Anti-Inflammatory Activities of Arnica montana Planta Tota versus Flower Extracts: Analytical, In Vitro and In Vivo Mouse Paw Oedema Model Studies.
- Author
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Röhrl, Johann, Piqué-Borràs, Maria-Riera, Jaklin, Manuela, Werner, Markus, Werz, Oliver, Josef, Heinke, Hölz, Hubert, Ammendola, Aldo, and Künstle, Gerald
- Subjects
ANTI-inflammatory agents ,EDEMA ,ARACHIDONIC acid ,MICE ,BLOOD cells ,VENOM - Abstract
Arnica montana is well known for its anti-inflammatory properties. While the anti-inflammatory activity of Arnica flowers (Arnicae flos) has been extensively studied, that of the whole plant (Arnicae planta tota) is less characterized. We compared the ability of Arnicae planta tota and Arnicae flos extracts to inhibit the pro-inflammatory NF-κB—eicosanoid pathway, using several in vitro and in vivo assays. We showed that Arnicae planta tota inhibited NF-κB reporter activation, with an IC
50 of 15.4 μg/mL (vs. 52.5 μg/mL for Arnicae flos). Arnicae planta tota also inhibited LPS-induced expression of ALOX5 and PTGS2 genes in human differentiated macrophages. ALOX5 and PTGS2 encode the 5-lipoxygenase (5-LO) and cyclooxygenase-2 (COX-2) enzymes that initialize the conversion of arachidonic acid into leukotrienes and prostaglandins, respectively. Arnicae planta tota inhibited 5-LO and COX-2 enzymatic activity in vitro and in human primary peripheral blood cells, with lower IC50 compared to Arnicae flos. Finally, Arnicae planta tota applied topically reduced carrageenan-induced mouse paw oedema more efficiently than Arnicae flos. Altogether, Arnicae planta tota displayed a superior anti-inflammatory activity compared to Arnicae flos, suggesting that Arnicae-planta-tota-containing products might be more effective in alleviating the manifestations of acute inflammation than those based on Arnicae flos alone. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
3. The 55-kD Tumor Necrosis Factor Receptor and CD95 Independently Signal Murine Hepatocyte Apoptosis and Subsequent Liver Failure
- Author
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Leist, Marcel, Gantner, Florian, Künstle, Gerald, Bohlinger, Ines, Tiegs, Gisa, Bluethmann, Horst, and Wendel, Albrecht
- Published
- 1996
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4. Herbal Amara extract induces gastric fundus relaxation via inhibition of the M2 muscarinic receptor.
- Author
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Piqué‐Borràs, Maria‐Riera, Röhrl, Johann, and Künstle, Gerald
- Abstract
Background Methods Key Results Conclusion and Inferences Impaired gastric accommodation is one of the most frequent symptoms of functional dyspepsia. The safety and efficacy of conventional treatments remain to be proven and alternative herbal therapies have been proposed to alleviate gastrointestinal symptoms. This preclinical study examined the role of herbal Amara extract (containing Artemisia absinthium, Centaurium erythraea, Cichorium intybus, Gentiana lutea, Juniperus communis, Achillea millefolium, Peucedanum ostruthium, Salvia officinalis, and Taraxacum extracts) on gastric (fundus) accommodation and the possible implication of muscarinic receptors in its regulation.The effect of Amara extract on fundus motility was investigated in organ baths of smooth muscle strips isolated from the fundus of guinea pigs, and the role of the muscarinic receptor pathway was evaluated using functional and radioligand binding assays in cell lines expressing the M2 or M3 muscarinic receptor.Amara extract inhibited carbachol‐induced contraction of guinea pig smooth muscle strips in a dose‐dependent manner. This relaxant effect was not affected by the M3 antagonist J‐104129. Amara extract also inhibited M2, but not M3, receptor activity in CHO‐K1 cells (IC50 219 μg mL−1), and specifically bound the M2 receptor (IC50 294 μg mL−1). Of the nine herbal components of Amara extract, Juniperus communis, P. ostruthium, and Salvia officinalis inhibited M2 receptor activity (IC50 32.0, 20.8, and 20.1 μg mL−1, respectively), and P. ostruthium was sufficient to reverse carbachol‐induced ex vivo contraction of guinea pig fundic smooth muscles.Amara extract relaxes gastric smooth muscles by inhibiting the M2 muscarinic receptor. This study suggests the potential benefit of Amara extract for patients with impaired gastric accommodation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Metabolic Depletion of ATP by Fructose Inversely Controls CD95- and Tumor Necrosis Factor Receptor 1-mediated Hepatic Apoptosis
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Latta, Markus, Künstle, Gerald, Leist, Marcel, and Wendel, Albrecht
- Published
- 2000
6. Cytokine-Mediated Hepatic Apoptosis
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Leist, Marcel, Gantner, Florian, Wendel, Albrecht, and Künstle, Gerald
- Subjects
ddc:570 - Abstract
Thirty years ago liver pathology defined apoptosis as a novel mode of cell death. Recently, experimental models of liver injury have been made available for examining the signaling molecules and receptors of apoptotic mechanisms as well as their pathological relevance. Experimental evidence suggests the involvement of apoptosis not only in various inflammatory liver disorders, but also in conditions of poisoning with xenobiotic hepatotoxins. The presence of several differentially regulated apoptosismediating receptors and their ligands on hepatocytes may explain the liver's susceptibility to autoimmune reactions, toxins, and viruses causing chronic liver disease, as well as the differential sensitivity of this system in various metabolic and pathologic conditions. Tumor necrosis factor (TNF) and its receptors (TNF-R), as well as CD95L and its receptor (CD95), are well-known cytokine/cytokine receptor systems relevant to hepatic disease and to apoptosis. Neutralization of endogenously released TNF prevents hepatocyte apoptosis associated with inflammatory liver damage. Direct injection of TNF in sensitized mice results in large scale hepatocyte apoptosis which is exclusively and selectively mediated by the 55-kDa TNF-R. Fulminant apoptotic liver damage is also triggered upon stimulation of CD95. Possible triggering cells include hepatocytes that express CD95L under pathological conditions. Despite the lack of interaction between TNF-R and CD95 on the receptor level, their signal transduction inside the cell seems to involve common proteolytic steps since inhibition of proteases of the caspase family blocks hepatocyte death, liver damage, or lethality in mice signaled by either receptor.
- Published
- 1998
7. Vitex agnus-castus dry extract BNO 1095 (Agnucaston) inhibits uterine hyper-contractions and inflammation in experimental models for primary dysmenorrhea.
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Röhrl, Johann, Werz, Oliver, Ammendola, Aldo, and Künstle, Gerald
- Subjects
VITEX agnus-castus ,PLANT extracts ,UTERINE contraction ,TREATMENT of dysmenorrhea ,PREMENSTRUAL syndrome ,LEUKOTRIENES ,LABORATORY rats ,THERAPEUTICS - Abstract
Background: For many women, the monthly suffering induced by menstrual 'cramps' is severe enough to profoundly disrupt their quality of life. In the case of primary dysmenorrhea, a condition related to premenstrual syndrome (PMS), intense uterine contractions are thought to trigger moderate to intense pain despite the absence of an underlying infection or other medically-identifiable disease states. The associated uterine hyper-contractility is reminiscent of labor, and associated pain is likely to be mediated by the release of prostaglandins, leukotrienes and the infiltration of leukocytes that normally accompany the breakdown of the endometrial lining. Standardized extracts of Vitex agnus-castus berries (VAC extracts of chaste tree, or chaste berries) are clinically effective in treating the symptoms of PMS, yet the mechanisms of how the chemically complex mixture acts are largely unknown. Methods: Using an in vivo dysmenorrhea model rats were treated with 10 mg/kg estradiol-benzoate i.p. once daily for 12 days and with 2.1, 10.3 or 20.7 mg/kg VAC dry extract p.o. once daily for 7 days prior to induction of convulsions. Uterine contractions where induced with 2 IU/kg oxytocin i.p., followed by monitoring of abdominal convulsions and signs of pain on the last day of the experiment. Moreover, in vitro methods were applied that are described in the methods section. Results: Here, we show that the VAC herbal dry extract BNO 1095 (commercially available as Agnucaston) targets the uterine myometrial tissue and inflammatory signaling molecules of associated migratory/inflammatory cells. Specifically, BNO 1095 dose-dependently inhibited oxytocin-induced uterine contractions in a rat dysmenorrhea model in vivo and drug-induced contractions in isolated human and rat uterine tissue in vitro. Furthermore, BNO 1095 showed a promising anti-inflammatory capacity by potently inhibiting 5-lipoxygenase activity and leukotriene production and by reducing the production of reactive oxygen species and inflammatory cytokines in vitro. Conclusion: These results provide evidence that BNO 1095 effectively treats menstruation-related complaints including primary dysmenorrhea. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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- View/download PDF
8. ICE-protease inhibitors block murine liver injury and apoptosis caused by CD95 or by TNF-alpha
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Künstle, Gerald, Uhlig, Stefan, Revesz, Laszlo, Feifel, Roland, MacKenzie, Andrew, Leist, Marcel, and Wendel, Albrecht
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converting enzyme ,Fas/APO-1 ,ddc:570 ,Caspases ,TNF ,Interleukin-1 beta ,CPP32 ,biological phenomena, cell phenomena, and immunity ,ICE-like proteases - Abstract
The two apoptosis receptors of mammalian cells, i.e. the 55 kDa TNF receptor (TNF-R1) and CD95 (Fas/APO1) are activated independently of each other, however, their signaling involves a variety of ICE-related proteases. We used a cell-permeable inhibitor of ICE-like protease activity to examine in vivo whether post-receptor signaling of TNF and CD95 are fully independent processes. Mice pretreated with the inhibitor, Z-VAD-fluoromethylketone (FMK) were dose-dependently protected from liver injury caused by CD95 activation as determined by plasma alanine aminotransferase and also from hepatocyte apoptosis assessed by DNA fragmentation (ID50=0.1 mg/kg). A dose of 10 mg/kg protected mice also from liver injury induced by TNF-α. Similar results were found when apoptosis was initiated via TNF-α or via CD95 in primary murine hepatocytes (IC50=1.5 nM) or in various human cell lines. In addition to prevention, an arrest of cell death by Z-VAD-FMK was demonstrated in vivo and in vitro after stimulation of apoptosis receptors. These findings show in vitro and in vivo in mammals that CD95 and the TNF-α receptor share a distal proteolytic apoptosis signal.
- Published
- 1997
9. Differential immunotoxicity of histone deacetylase inhibitors on malignant and naïve hepatocytes.
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Weiller, Markus, Weiland, Timo, Dünstl, Georg, Sack, Ulrike, Künstle, Gerald, and Wendel, Albrecht
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LIVER cancer ,HISTONE deacetylase ,ENZYME inhibitors ,IMMUNOTOXICOLOGY ,LIVER cells ,CELL culture ,LABORATORY mice ,WESTERN immunoblotting ,APOPTOSIS - Abstract
Abstract: Histone deacetylases (HD) represent a novel target in cancer treatment, particularly for scattered small tumours such as the hepatocellular carcinoma (HCC). However, only few studies address the toxicological impact of HD Inhibitors (HDIs) on malignantly transformed cells versus primary hepatocytes. We examined whether and how different classes of HDIs sensitise the human HCC cell line HepG2, primary healthy murine and human liver cells towards the death receptor agonists TNFα and CD95L. Apicidin, M344 (N-hydroxy-7-(-4-dimethylaminobenzol)aminoheptanamide), CBHA (m-carboxycinnamic acid bis-hydroxamide) and VPA (valproic acid) sensitised liver cell cultures towards CD95-triggered apoptosis with the following potency: apicidin>M344≈CBHA≫VPA. Apicidin sensitised towards CD95 also in the intact organ, i.e. in the isolated perfused mouse liver. No significant sensitisation towards TNFα was found in vitro. Western blot analysis showed that all HDIs studied downregulated the anti-apoptotic protein cFLIP, but only VPA additionally affected the expression level of XIAP. Furthermore, in models of the intrinsic apoptosis pathway, i.e. in HepG2 cells treated with Melphalan and in primary hepatocytes irradiated with UV light, only VPA exhibited significant sensitisation. These findings extend the biochemical, pharmacological and toxicological basis for HDI therapy and provide a caveat for clinical use in patients with an accompanying critical inflammatory state in which the CD95 system might be pre-activated. [Copyright &y& Elsevier]
- Published
- 2011
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10. Redox control of hepatic cell death
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Hentze, Hannes, Latta, Markus, Künstle, Gerald, Lucas, Rudolf, and Wendel, Albrecht
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- 2003
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11. Topoisomerase inhibitor camptothecin sensitizes mouse hepatocytes in vitro and in vivo to TNF-mediated apoptosis.
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Hentze, Hannes, Latta, Markus, Künstle, Gerald, Dhakshinamoorthy, Saravanakumar, Ng, Poh Yong, Porter, Alan G., and Wendel, Albrecht
- Published
- 2004
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12. Concanavalin A hepatotoxicity in mice: Tumor necrosis factor-mediated organ failure independent of caspase-3-like protease activation.
- Author
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Künstle, Gerald, Hentze, Hannes, Germann, Paul-Georg, Tiegs, Gisa, Meergans, Thomas, and Wendel, Albrecht
- Published
- 1999
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13. CD95-mediated murine hepatic apoptosis requires an intact glutathione status.
- Author
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Hentze, Hannes, Künstle, Gerald, Volbracht, Christiane, Ertel, Wolfgang, and Wendel, Albrecht
- Published
- 1999
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14. In vivo evidence for a functional role of both tumor necrosis factor (TNF) receptors and transmembrane TNF in experimental hepatitis.
- Author
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Küsters, Sabine, Tiegs, Gisa, Alexopoulou, Lena, Pasparakis, Manolis, Douni, Eleni, Künstle, Gerald, Bluethmann, Horst, Wendel, Albrecht, Pfizenmaier, Klaus, Kollias, George, and Grell, Matthias
- Published
- 1997
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15. The standardized herbal combination BNO 2103 contained in Canephron® N alleviates inflammatory pain in experimental cystitis and prostatitis.
- Author
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Nausch, Bernhard, Pace, Simona, Pein, Helmut, Koeberle, Andreas, Rossi, Antonietta, Künstle, Gerald, and Werz, Oliver
- Abstract
Background: Urinary tract infections are among the most common types of infections and give rise to inflammation with pain as one of the main symptoms. The herbal medicinal product Canephron® N contains BNO 2103, a defined mixture of pulverized rosemary leaves, centaury herb, and lovage root, and has been used in the treatment of urinary tract infections for more than 25 years.Purpose: To test the hypothesis that BNO 2103 reduces pain in cystitis and prostatitis by virtue of anti-inflammatory properties, and to reveal potential mechanisms underlying the anti-inflammatory features.Study Design: BNO 2103 was studied for anti-inflammatory and analgesic properties in three animal models in vivo, and the mode of action underlying the anti-inflammatory features was investigated in human leukocytes and cell-free assays in vitro.Methods: To assess the anti-inflammatory and analgesic efficacy of BNO 2103 we employed cyclophosphamide-induced cystitis and carrageenan-induced prostatitis in rats, and zymosan-induced peritonitis in mice. Human neutrophils and monocytes as well as isolated human 5-lipoxygenase and microsomal prostaglandin E2 synthase-1-containing microsomes were utilized to assess inhibition of leukotriene and/or prostaglandin E2 production by HPLC and/or ELISA.Results: When given orally, BNO 2103 reduced inflammation and hyperalgesia in experimental cystitis in rats, while individual components of BNO 2103 also reduced hyperalgesia. Furthermore, BNO 2103 reduced hyperalgesia in rats with carrageenan-induced prostatitis. Cell-based and cell-free studies implicate inhibition of prostaglandin E2 and leukotriene B4 biosynthesis as potential mechanisms underlying the analgesic and anti-inflammatory effects.Conclusion: Our data support the hypothesis that BNO 2103 reduces pain by virtue of its anti-inflammatory properties, possibly related to suppression of prostaglandin E2 and leukotriene B4 formation, and suggest that this combination has the potential to treat clinical symptoms such as inflammatory pain. Thus BNO 2103 may represent an alternative to reduce the use of antibiotics in urinary tract infections. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
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16. Serotonin receptor targeting activities for Cimicifuga racemosa dry extract (BNO 1055) as active component of Klimadynon®.
- Author
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Röhrl, Johann and Künstle, Gerald
- Subjects
- *
SEROTONIN receptors , *BUGBANE , *PHYTOTHERAPY , *CLIMACTERIC ,THERAPEUTIC use of plant extracts - Published
- 2017
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17. ICE-protease inhibitors block murine liver injury and apoptosis caused by CD95 or by TNF-α
- Author
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Künstle, Gerald, Leist, Marcel, Uhlig, Stefan, Revesz, Laszlo, Feifel, Roland, MacKenzie, Andrew, and Wendel, Albrecht
- Published
- 1997
- Full Text
- View/download PDF
18. Activation of an alternative death receptor-induced signaling pathway in human hepatocytes under caspase arrest
- Author
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Dünstl, Georg, Weiland, Timo, Schlaeger, Christof, Nüssler, Andreas, Künstle, Gerald, and Wendel, Albrecht
- Subjects
- *
CELL death , *LIVER cells , *APOPTOSIS , *AMINO acids - Abstract
Abstract: Caspases are thought to be essential in execution of death receptor-induced apoptosis. However, recent findings suggest the existence of alternative pathways independent of caspases. We provide further evidence for such signaling in hepatocytes. Results: Death receptor-induced activation of caspases and apoptosis in primary murine hepatocytes was completely blocked in presence of 1.5μM N-benzyloxycarbonyl-Val-Ala-Asp-(O-methyl)fluoromethylketone (zVAD-fmk). Whereas the same concentration of the inhibitor was sufficient to block TNF receptor 1-, CD95- or TRAIL receptor 1/-2-induced activation of caspases in primary human hepatocytes or HepG2 cells, complete prevention apoptotic cell death needed almost 100μM zVAD-fmk. Under caspase-inhibitory but non-protective conditions, i.e. at 1.5μM zVAD-fmk, various serine protease inhibitors prevented apoptosis-like cell death. Neither sole arrest of caspases nor inhibition of serine proteases alone protected human hepatocytes. Conclusion: Human but not murine hepatocytes bear the potential to activate a permissive, serine protease inhibitor-sensitive alternative death signaling pathway under caspase-inhibitory conditions. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
19. The standardized herbal combination BNO 2103 contained in Canephron ® N alleviates inflammatory pain in experimental cystitis and prostatitis.
- Author
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Nausch B, Pace S, Pein H, Koeberle A, Rossi A, Künstle G, and Werz O
- Subjects
- Analgesics chemistry, Animals, Anti-Inflammatory Agents chemistry, Carrageenan adverse effects, Cyclophosphamide adverse effects, Cystitis chemically induced, Drugs, Chinese Herbal, Female, Humans, Hyperalgesia drug therapy, Hyperalgesia etiology, Inflammation drug therapy, Inflammation etiology, Male, Mice, Monocytes drug effects, Neutrophils drug effects, Pain etiology, Plant Extracts chemistry, Prostatitis chemically induced, Rats, Rats, Sprague-Dawley, Analgesics pharmacology, Anti-Inflammatory Agents pharmacology, Cystitis complications, Pain drug therapy, Plant Extracts pharmacology, Prostatitis complications
- Abstract
Background: Urinary tract infections are among the most common types of infections and give rise to inflammation with pain as one of the main symptoms. The herbal medicinal product Canephron
® N contains BNO 2103, a defined mixture of pulverized rosemary leaves, centaury herb, and lovage root, and has been used in the treatment of urinary tract infections for more than 25 years., Purpose: To test the hypothesis that BNO 2103 reduces pain in cystitis and prostatitis by virtue of anti-inflammatory properties, and to reveal potential mechanisms underlying the anti-inflammatory features., Study Design: BNO 2103 was studied for anti-inflammatory and analgesic properties in three animal models in vivo, and the mode of action underlying the anti-inflammatory features was investigated in human leukocytes and cell-free assays in vitro., Methods: To assess the anti-inflammatory and analgesic efficacy of BNO 2103 we employed cyclophosphamide-induced cystitis and carrageenan-induced prostatitis in rats, and zymosan-induced peritonitis in mice. Human neutrophils and monocytes as well as isolated human 5-lipoxygenase and microsomal prostaglandin E2 synthase-1-containing microsomes were utilized to assess inhibition of leukotriene and/or prostaglandin E2 production by HPLC and/or ELISA., Results: When given orally, BNO 2103 reduced inflammation and hyperalgesia in experimental cystitis in rats, while individual components of BNO 2103 also reduced hyperalgesia. Furthermore, BNO 2103 reduced hyperalgesia in rats with carrageenan-induced prostatitis. Cell-based and cell-free studies implicate inhibition of prostaglandin E2 and leukotriene B4 biosynthesis as potential mechanisms underlying the analgesic and anti-inflammatory effects., Conclusion: Our data support the hypothesis that BNO 2103 reduces pain by virtue of its anti-inflammatory properties, possibly related to suppression of prostaglandin E2 and leukotriene B4 formation, and suggest that this combination has the potential to treat clinical symptoms such as inflammatory pain. Thus BNO 2103 may represent an alternative to reduce the use of antibiotics in urinary tract infections., (Copyright © 2019 Elsevier GmbH. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
20. Sensitization by 5-azacytidine toward death receptor-induced hepatic apoptosis.
- Author
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Weiland T, Weiller M, Künstle G, and Wendel A
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- Animals, Apoptosis drug effects, Caspases metabolism, Cell Culture Techniques, Cell Death drug effects, Cell Death physiology, Cell Survival drug effects, Hepatocytes drug effects, Hepatocytes pathology, Humans, Liver drug effects, Liver Neoplasms pathology, Liver Neoplasms surgery, Mice, Microscopy, Fluorescence, Apoptosis physiology, Azacitidine pharmacology, Hepatocytes physiology, Liver cytology, Liver physiology, Receptors, Death Domain agonists, Receptors, Death Domain physiology
- Abstract
5-Azacytidine (5-aza-CR) is a DNA-hypomethylating antineoplastic agent used because of its inhibitory activity on DNA methyltransferases. Today, it is approved as an epigenetically active drug therapy for treatment of myelodysplastic disorders, with a contraindication as to pre-existing liver diseases. Because the mechanism of its hepatotoxicity is still unknown, we investigated the pharmacodynamic properties of 5-aza-CR with regard to death receptor/ligand-induced apoptosis and the mode of execution of cell death. In a time- and concentration-dependent manner, primary murine, human hepatocytes and HepG2 cells exposed to 5-aza-CR became highly sensitive toward cell death induced by CD95L, tumor necrosis factor (TNF)-related apoptosis-inducing ligand, or TNF. Cell death was characterized as apoptotic by membrane blebbing, chromatin condensation, and exposure of phosphatidylserine on the outer membrane. Neither 5-aza-2'-deoxycytidine nor the common DNA methyltransferase inhibitors S-(5'-adenosyl)-L-homocysteine or RG 108 showed any significant effects under these conditions. Despite the complete protection of HepG2 by high concentrations of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp(O-Me) fluoromethyl ketone (z-VAD-fmk), effector caspase-3/7 activity was completely abolished at approximately a 20-fold lower concentration of z-VAD-fmk. Under these conditions, the serine protease inhibitors N,alpha-tosyl-L-phenylalanine chloromethyl ketone, N,p-tosyl-L-lysine chloromethyl ketone, and 4-(2-aminoethyl)-benzenesulfonyl fluoride, respectively, conferred protection against death receptor ligands. We conclude that this caspase-independent apoptosis is executed by a yet-unidentified serine protease.
- Published
- 2009
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21. ATP-depleting carbohydrates prevent tumor necrosis factor receptor 1-dependent apoptotic and necrotic liver injury in mice.
- Author
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Latta M, Künstle G, Lucas R, Hentze H, and Wendel A
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- Adenosine pharmacology, Alanine Transaminase blood, Animals, Caspase 3 metabolism, Caspase 8 metabolism, Cell Survival drug effects, Cells, Cultured, Dactinomycin pharmacology, Hepatocytes cytology, Hepatocytes drug effects, Hepatocytes metabolism, Interferon-gamma blood, Interleukin-4 blood, Lipopolysaccharides pharmacology, Liver metabolism, Liver pathology, Male, Mice, Mice, Inbred BALB C, Models, Biological, NF-kappa B metabolism, Necrosis prevention & control, T-Lymphocytes cytology, T-Lymphocytes drug effects, T-Lymphocytes metabolism, Tumor Necrosis Factor-alpha blood, Tumor Necrosis Factor-alpha metabolism, Tumor Necrosis Factor-alpha pharmacology, Adenosine Triphosphate metabolism, Apoptosis drug effects, Hexoses pharmacology, Liver drug effects, Receptors, Tumor Necrosis Factor, Type I metabolism
- Abstract
We demonstrated previously that depletion of hepatic ATP by endogenous metabolic shunting of phosphate after fructose treatment renders hepatocytes resistant to tumor necrosis factor (TNF)-induced apoptosis. We here address the question whether this principle extends to TNF receptor 1-mediated caspase-independent apoptotic and to necrotic liver injury. As in the apoptotic model of galactosamine/lipopolysaccharide (LPS)-induced liver damage, the necrotic hepatotoxicity initiated by sole high-dose LPS treatment was abrogated after depletion of hepatic ATP. Although systemic TNF and interferon-gamma levels were suppressed, animals still were protected when ATP depletion was initiated after the peak of proinflammatory cytokines upon LPS injection, showing that fructose-induced ATP depletion affects both cytokine release and action. In T cell-dependent necrotic hepatotoxicity elicited by concanavalin A or galactosamine + staphylococcal enterotoxin B, ATP depletion prevented liver injury as well, but here without modulating cytokine release. By attenuating caspase-8 activation, ATP depletion of hepatocytes in vitro impaired TNF receptor signaling by the death-inducing signaling complex, whereas receptor internalization and nuclear factor-kappaB activation upon TNF stimulation were unaffected. These findings demonstrate that sufficient target cell ATP levels are required for the execution of both apoptotic and necrotic TNF-receptor 1-mediated liver cell death.
- Published
- 2007
- Full Text
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22. Kupffer cell-expressed membrane-bound TNF mediates melphalan hepatotoxicity via activation of both TNF receptors.
- Author
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Kresse M, Latta M, Künstle G, Riehle HM, van Rooijen N, Hentze H, Tiegs G, Biburger M, Lucas R, and Wendel A
- Subjects
- ADAM Proteins antagonists & inhibitors, ADAM17 Protein, Animals, Apoptosis, Caspases metabolism, Cell Communication, Cells, Cultured, Hepatocytes pathology, Liver Diseases etiology, Male, Membrane Proteins, Mice, Mice, Inbred C57BL, Mice, Knockout, Chemical and Drug Induced Liver Injury, Kupffer Cells metabolism, Melphalan adverse effects, Receptors, Tumor Necrosis Factor, Type I metabolism, Receptors, Tumor Necrosis Factor, Type II metabolism, Tumor Necrosis Factor-alpha metabolism
- Abstract
Isolated hepatic perfusion of nonresectable liver cancer using the combination of TNF and melphalan can be associated with a treatment-related hepatotoxicity. We investigated whether, apart from TNF, also melphalan is cytotoxic in primary murine liver cells in vitro and investigated mediators, mode of cell death, and cell types involved. Melphalan induced a caspase-dependent apoptosis in hepatocytes, which was not seen in liver cell preparations depleted of Kupffer cells. Neutralization of TNF prevented melphalan-induced apoptosis and liver cells derived from mice genetically deficient in either TNFR 1 or 2, but not from lpr mice lacking a functional CD95 receptor, were completely resistant. Cell-cell contact between hepatocytes and Kupffer cells was required for apoptosis to occur. Melphalan increased membrane-bound but not secreted TNF in Kupffer cells and inhibited recombinant TNF-alpha converting enzyme in vitro. Melphalan induced also severe hepatotoxicity in the isolated recirculating perfused mouse liver from wild-type mice but not from TNFR 1 or 2 knockout mice. In conclusion, this study shows that melphalan elicits membrane TNF on Kupffer cells due to inhibition of TNF processing and thereby initiates apoptosis of hepatocytes via obligatory activation of both TNFRs. The identification of this novel mechanism allows a causal understanding of melphalan-induced hepatotoxicity.
- Published
- 2005
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23. Identification of Akt association and oligomerization domains of the Akt kinase coactivator TCL1.
- Author
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Künstle G, Laine J, Pierron G, Kagami Si S, Nakajima H, Hoh F, Roumestand C, Stern MH, and Noguchi M
- Subjects
- Active Transport, Cell Nucleus, Apoptosis, Binding Sites, Enzyme Activation, Glutamic Acid, Humans, Isoleucine, Models, Molecular, Mutation, Protein Binding, Protein Conformation, Protein Structure, Secondary, Proto-Oncogene Mas, Proto-Oncogene Proteins c-akt, Protein Serine-Threonine Kinases, Proto-Oncogene Proteins metabolism
- Abstract
Serine/threonine kinase Akt/protein kinase B, the cellular homologue of the transforming viral oncogene v-Akt, plays a central role in the regulation of cell survival and proliferation. We have previously demonstrated that the proto-oncogene TCL1 is an Akt kinase coactivator. TCL1 binds to Akt and mediates the formation of oligomeric TCL1-Akt high-molecular-weight protein complexes in vivo. Within these protein complexes, Akt is preferentially phosphorylated and activated. The MTCP1/TCL1/TCL1b oncogene activation is the hallmark of human T-cell prolymphocytic leukemia (T-PLL), a form of adult leukemia. In the present study, using a PCR-generated random TCL1 library combined with a yeast two-hybrid screening detecting loss of interaction, we identified D16 and I74 as amino acid residues mediating the association of TCL1 with Akt. Based on molecular modeling, we determined that the beta C-sheet of TCL1 is essential for TCL1 homodimerization. Studies with mammalian overexpression systems demonstrated that both Akt association and oligomerization domains of TCL1 are distinct functional domains. In vitro kinase assays and overexpression experiments in mammalian cells demonstrated that both TCL1-Akt interaction and oligomerization of TCL1 were required for TCL1-induced Akt activation and substrate phosphorylation. Assays for mitochondrial permeability transition, nuclear translocation, and cell recovery demonstrated that both Akt association and homodimerization of TCL1 are similarly needed for the full function of TCL1 as an Akt kinase coactivator in vivo. The results demonstrate the structural basis of TCL1-induced activation of Akt, which causes human T-PLL.
- Published
- 2002
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24. Differential regulation of Akt kinase isoforms by the members of the TCL1 oncogene family.
- Author
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Laine J, Künstle G, Obata T, and Noguchi M
- Subjects
- Animals, Cell Line, Cloning, Molecular, DNA Primers, Glutathione Transferase genetics, Humans, Kinetics, Mammals, Phosphorylation, Polymerase Chain Reaction, Protein Binding, Protein-Tyrosine Kinases genetics, Protein-Tyrosine Kinases metabolism, Proto-Oncogene Mas, Proto-Oncogene Proteins metabolism, Proto-Oncogene Proteins c-akt, Recombinant Fusion Proteins metabolism, Restriction Mapping, T-Lymphocytes, Transfection, Gene Expression Regulation, Enzymologic, Protein Serine-Threonine Kinases, Proto-Oncogene Proteins genetics, Proto-Oncogenes
- Abstract
The members of the TCL1 proto-oncogene family (TCL1, MTCP1, and TCL1b) bind to Akt1, increasing its phosphorylation status and kinase activity. This is thought to be secondary to the formation of TCL1-Akt oligomers within which Akt is preferentially phosphorylated. Here we show that, in contrast to Akt1 and Akt2, which bind to all members of the TCL1 family, Akt3 specifically interacts with TCL1 but not with MTCP1 or TCL1b. This association is functional, as the presence of TCL1 but not MTCP1 or TCL1b increased Akt3 kinase activity in in vitro kinase assays. Functional specificity is determined by the Akt pleckstrin homology domain as chimeric Akt1, where Akt1 PH domain was replaced by that of Akt3 was no longer able to interact with MTCP1 or TCL1b and its kinase activity was solely enhanced by TCL1. Moreover, we show that, in TCL1-overexpressing SUPT-11 T-cell leukemia and P3HR-1 Burkitt's lymphoma cell lines, TCL1 interacts with endogenous Akt1, Akt2, and Akt3. TCL1 enhanced hetero-oligomerization of Akt1 with Akt3 and as a consequence facilitated transphosphorylation of Akt molecules, which may contribute to Akt activation and TCL1-induced leukemogenesis in vivo.
- Published
- 2002
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