TY - JOUR A1 - Bhabak, Krishna P. A1 - Kleuser, Burkhard A1 - Huwiler, Andrea A1 - Arenz, Christoph T1 - Effective inhibition of acid and neutral ceramidases by novel B-13 and LCL-464 analogues JF - Bioorganic & medicinal chemistry : a Tetrahedron publication for the rapid dissemination of full original research papers and critical reviews on biomolecular chemistry, medicinal chemistry and related disciplines N2 - Induction of apoptosis mediated by the inhibition of ceramidases has been shown to enhance the efficacy of conventional chemotherapy in several cancer models. Among the inhibitors of ceramidases reported in the literature, B-13 is considered as a lead compound having good in vitro potency towards acid ceramidase. Furthermore, owing to the poor activity of B-13 on lysosoamal acid ceramidase in living cells, LCL-464 a modified derivative of B-13 containing a basic omega-amino group at the fatty acid was reported to have higher potency towards lysosomal acid ceramidase in living cells. In a search for more potent inhibitors of ceramidases, we have designed a series of compounds with structural modifications of B-13 and LCL-464. In this study, we show that the efficacy of B-13 in vitro as well as in intact cells can be enhanced by suitable modification of functional groups. Furthermore, a detailed SAR investigation on LCL-464 analogues revealed novel promising inhibitors of aCDase and nCDase. In cell culture studies using the breast cancer cell line MDA-MB-231, some of the newly developed compounds elevated endogenous ceramide levels and in parallel, also induced apoptotic cell death. In summary, this study shows that structural modification of the known ceramidase inhibitors B-13 and LCL-464 generates more potent ceramidase inhibitors that are active in intact cells and not only elevates the cellular ceramide levels, but also enhances cell death. KW - Sphingolipids KW - Ceramide KW - Ceramidase inhibitors KW - Structure-activity-relationship Y1 - 2013 U6 - https://doi.org/10.1016/j.bmc.2012.12.014 SN - 0968-0896 VL - 21 IS - 4 SP - 874 EP - 882 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - McVey, Mark J. A1 - Kim, Michael A1 - Tabuchi, Arata A1 - Srbely, Victoria A1 - Japtok, Lukasz A1 - Arenz, Christoph A1 - Rotstein, Ori A1 - Kleuser, Burkhard A1 - Semple, John W. A1 - Kuebler, Wolfgang M. T1 - Acid sphingomyelinase mediates murine acute lung injury following transfusion of aged platelets JF - American journal of physiology : Lung cellular and molecular physiology N2 - Pulmonary complications from stored blood products are the leading cause of mortality related to transfusion. Transfusion-related acute lung injury is mediated by antibodies or bioactive mediators, yet underlying mechanisms are incompletely understood. Sphingolipids such as ceramide regulate lung injury, and their composition changes as a function of time in stored blood. Here, we tested the hypothesis that aged platelets may induce lung injury via a sphingolipid-mediated mechanism. To assess this hypothesis, a two-hit mouse model was devised. Recipient mice were treated with 2 mg/kg intraperitoneal lipopolysaccharide (priming) 2 h before transfusion of 10 ml/kg stored (1-5 days) platelets treated with or without addition of acid sphingomyelinase inhibitor ARC39 or platelets from acid sphingomyelinase-deficient mice, which both reduce ceramide formation. Transfused mice were examined for signs of pulmonary neutrophil accumulation, endothelial barrier dysfunction, and histological evidence of lung injury. Sphingolipid profiles in stored platelets were analyzed by mass spectrophotometry. Transfusion of aged platelets into primed mice induced characteristic features of lung injury, which increased in severity as a function of storage time. Ceramide accumulated in platelets during storage, but this was attenuated by ARC39 or in acid sphingomyelinase-deficient platelets. Compared with wild-type platelets, transfusion of ARC39-treated or acid sphingomyelinase-deficient aged platelets alleviated lung injury. Aged platelets elicit lung injury in primed recipient mice, which can be alleviated by pharmacological inhibition or genetic deletion of acid sphingomyelinase. Interventions targeting sphingolipid formation represent a promising strategy to increase the safety and longevity of stored blood products. KW - transfusion-related acute lung injury KW - ceramide KW - acid sphingomyelinase KW - platelets KW - storage Y1 - 2017 U6 - https://doi.org/10.1152/ajplung.00317.2016 SN - 1040-0605 SN - 1522-1504 VL - 312 IS - 5 SP - 625 EP - 637 PB - American Physiological Society CY - Bethesda ER - TY - GEN A1 - Naser, Eyad A1 - Kadow, Stephanie A1 - Schumacher, Fabian A1 - Mohamed, Zainelabdeen H. A1 - Kappe, Christian A1 - Hessler, Gabriele A1 - Pollmeier, Barbara A1 - Kleuser, Burkhard A1 - Arenz, Christoph A1 - Becker, Katrin Anne A1 - Gulbins, Erich A1 - Carpinteiro, Alexander T1 - Characterization of the small molecule ARC39 BT - a direct and specific inhibitor of acid sphingomyelinase in vitro[S] T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Inhibition of acid sphingomyelinase (ASM), a lysosomal enzyme that catalyzes the hydrolysis of sphingomyelin into ceramide and phosphorylcholine, may serve as an investigational tool or a therapeutic intervention to control many diseases. Specific ASM inhibitors are currently not sufficiently characterized. Here, we found that 1-aminodecylidene bis-phosphonic acid (ARC39) specifically and efficiently (>90%) inhibits both lysosomal and secretory ASM in vitro. Results from investigating sphingomyelin phosphodiesterase 1 (SMPD1/Smpd1) mRNA and ASM protein levels suggested that ARC39 directly inhibits ASM's catalytic activity in cultured cells, a mechanism that differs from that of functional inhibitors of ASM. We further provide evidence that ARC39 dose- and time-dependently inhibits lysosomal ASM in intact cells, and we show that ARC39 also reduces platelet- and ASM-promoted adhesion of tumor cells. The observed toxicity of ARC39 is low at concentrations relevant for ASM inhibition in vitro, and it does not strongly alter the lysosomal compartment or induce phospholipidosis in vitro. When applied intraperitoneally in vivo, even subtoxic high doses administered short-term induced sphingomyelin accumulation only locally in the peritoneal lavage without significant accumulation in plasma, liver, spleen, or brain. These findings require further investigation with other possible chemical modifications. In conclusion, our results indicate that ARC39 potently and selectively inhibits ASM in vitro and highlight the need for developing compounds that can reach tissue concentrations sufficient for ASM inhibition in vivo. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1407 KW - sphingolipids KW - sphingomyelin KW - cerami-des KW - lipid metabolism KW - enzymology KW - lysosome KW - lysosomal hydrolases KW - acid ceramidase KW - bisphosphonates KW - functional inhibitors of acid sphin-gomyelinase KW - 1-aminodecylidene bis-phosphonic acid Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516635 SN - 1866-8372 IS - 6 ER - TY - JOUR A1 - Naser, Eyad A1 - Kadow, Stephanie A1 - Schumacher, Fabian A1 - Mohamed, Zainelabdeen H. A1 - Kappe, Christian A1 - Hessler, Gabriele A1 - Pollmeier, Barbara A1 - Kleuser, Burkhard A1 - Arenz, Christoph A1 - Becker, Katrin Anne A1 - Gulbins, Erich A1 - Carpinteiro, Alexander T1 - Characterization of the small molecule ARC39 BT - a direct and specific inhibitor of acid sphingomyelinase in vitro[S] JF - Journal of Lipid Research N2 - Inhibition of acid sphingomyelinase (ASM), a lysosomal enzyme that catalyzes the hydrolysis of sphingomyelin into ceramide and phosphorylcholine, may serve as an investigational tool or a therapeutic intervention to control many diseases. Specific ASM inhibitors are currently not sufficiently characterized. Here, we found that 1-aminodecylidene bis-phosphonic acid (ARC39) specifically and efficiently (>90%) inhibits both lysosomal and secretory ASM in vitro. Results from investigating sphingomyelin phosphodiesterase 1 (SMPD1/Smpd1) mRNA and ASM protein levels suggested that ARC39 directly inhibits ASM's catalytic activity in cultured cells, a mechanism that differs from that of functional inhibitors of ASM. We further provide evidence that ARC39 dose- and time-dependently inhibits lysosomal ASM in intact cells, and we show that ARC39 also reduces platelet- and ASM-promoted adhesion of tumor cells. The observed toxicity of ARC39 is low at concentrations relevant for ASM inhibition in vitro, and it does not strongly alter the lysosomal compartment or induce phospholipidosis in vitro. When applied intraperitoneally in vivo, even subtoxic high doses administered short-term induced sphingomyelin accumulation only locally in the peritoneal lavage without significant accumulation in plasma, liver, spleen, or brain. These findings require further investigation with other possible chemical modifications. In conclusion, our results indicate that ARC39 potently and selectively inhibits ASM in vitro and highlight the need for developing compounds that can reach tissue concentrations sufficient for ASM inhibition in vivo. KW - sphingolipids KW - sphingomyelin KW - cerami-des KW - lipid metabolism KW - enzymology KW - lysosome KW - lysosomal hydrolases KW - acid ceramidase KW - bisphosphonates KW - functional inhibitors of acid sphin-gomyelinase KW - 1-aminodecylidene bis-phosphonic acid Y1 - 2021 U6 - https://doi.org/10.1194/jlr.RA120000682 SN - 1539-7262 SN - 0022-2275 VL - 61 IS - 6 SP - 896 EP - 910 PB - American Society for Biochemistry and Molecular Biology CY - Bethesda ER - TY - JOUR A1 - Samaha, Doaa A1 - Hamdo, Housam H. A1 - Cong, Xiaojing A1 - Schumacher, Fabian A1 - Banhart, Sebastian A1 - Aglar, Öznur A1 - Möller, Heiko Michael A1 - Heuer, Dagmar A1 - Kleuser, Burkhard A1 - Saied, Essa M. A1 - Arenz, Christoph T1 - Liposomal FRET assay identifies potent drug-like inhibitors of the Ceramide Transport Protein (CERT) JF - Chemistry - a European journal N2 - Ceramide transfer protein (CERT) mediates non-vesicular transfer of ceramide from endoplasmic reticulum to Golgi apparatus and thus catalyzes the rate-limiting step of sphingomyelin biosynthesis. Usually, CERT ligands are evaluated in tedious binding assays or non-homogenous transfer assays using radiolabeled ceramides. Herein, a facile and sensitive assay for CERT, based on Forster resonance energy transfer (FRET), is presented. To this end, we mixed donor and acceptor vesicles, each containing a different fluorescent ceramide species. By CERT-mediated transfer of fluorescent ceramide, a FRET system was established, which allows readout in 96-well plate format, despite the high hydrophobicity of the components. Screening of a 2 000 compound library resulted in two new potent CERT inhibitors. One is approved for use in humans and one is approved for use in animals. Evaluation of cellular activity by quantitative mass spectrometry and confocal microscopy showed inhibition of ceramide trafficking and sphingomyelin biosynthesis. KW - enzyme assays KW - Forster resonance energy transfer (FRET) KW - liposomes KW - sphingolipids KW - transport proteins Y1 - 2020 U6 - https://doi.org/10.1002/chem.202003283 SN - 0947-6539 SN - 1521-3765 VL - 26 IS - 70 SP - 16616 EP - 16621 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Zivanovic, Vesna A1 - Kochovski, Zdravko A1 - Arenz, Christoph A1 - Lu, Yan A1 - Kneipp, Janina T1 - SERS and Cryo-EM Directly Reveal Different Liposome Structures during Interaction with Gold Nanoparticles JF - The journal of physical chemistry letters N2 - The combination of gold nanoparticles with liposomes is important for nano- and biotechnology. Here, we present direct, label-free characterization of liposome structure and composition at the site of its interaction with citrate-stabilized gold nanoparticles by surface-enhanced Raman scattering (SERS) and cryogenic electron microscopy (cryo-EM). Evidenced by the vibrational spectra and cryo-EM, the gold nanoparticles destroy the bilayer structure of interacting liposomes in the presence of a high amount of citrate, while at lower citrate concentration the nanoparticles interact with the surface of the intact liposomes. The spectra of phosphatidylcholine and phosphatidylcholine/sphingomyelin liposomes show that at the site of interaction the lipid chains are in the gel phase. The SERS spectra indicate that cholesterol has strong effects on the contacts of the vesicles with the nanoparticles. By combining cryo-EM and SERS, the structure and properties of lipid nanoparticle composites could be tailored for the development of drug delivery systems. Y1 - 2018 U6 - https://doi.org/10.1021/acs.jpclett.8b03191 SN - 1948-7185 VL - 9 IS - 23 SP - 6767 EP - 6772 PB - American Chemical Society CY - Washington ER -