47 results on '"Danker, Kerstin"'
Search Results
2. Irradiation of human oral mucosa by 233 nm far UV-C LEDs for the safe inactivation of nosocomial pathogens
- Author
-
Schleusener, Johannes, Lohan, Silke B., Busch, Loris, Zamudio Díaz, Daniela F., Opitz, Nevin, Sicher, Claudia, Lichtenthäler, Tom, Danker, Kerstin, Dommerich, Steffen, Filler, Thomas, Meinke, Martina C., and Zwicker, Paula
- Published
- 2023
- Full Text
- View/download PDF
3. The α1 integrin cytoplasmic tail interacts with phosphoinositides and interferes with Akt activation
- Author
-
Labus, Josephine, Tang, Kerstin, Henklein, Petra, Krüger, Ulrike, Hofmann, Andreas, Hondke, Sylvia, Wöltje, Kerstin, Freund, Christian, Lucka, Lothar, and Danker, Kerstin
- Published
- 2024
- Full Text
- View/download PDF
4. Dichloroacetate and PX-478 exhibit strong synergistic effects in a various number of cancer cell lines
- Author
-
Parczyk, Jonas, Ruhnau, Jérôme, Pelz, Carsten, Schilling, Max, Wu, Hao, Piaskowski, Nicole Nadine, Eickholt, Britta, Kühn, Hartmut, Danker, Kerstin, and Klein, Andreas
- Published
- 2021
- Full Text
- View/download PDF
5. Synergisms of genome and metabolism stabilizing antitumor therapy (GMSAT) in human breast and colon cancer cell lines: a novel approach to screen for synergism
- Author
-
Ruhnau, Jérôme, Parczyk, Jonas, Danker, Kerstin, Eickholt, Britta, and Klein, Andreas
- Published
- 2020
- Full Text
- View/download PDF
6. Inositol-C2-PAF acts as a biological response modifier and antagonizes cancer-relevant processes in mammary carcinoma cells
- Author
-
Pelz, Carsten, Häckel, Sonja, Semini, Geo, Schrötter, Sandra, Bintig, Willem, Stricker, Sebastian, Mrawietz, Gudrun, Klein, Andreas, Lucka, Lothar, Shmanai, Vadim, Eickholt, Britta, Hildmann, Annette, and Danker, Kerstin
- Published
- 2018
- Full Text
- View/download PDF
7. Synthetic glycosidated phospholipids induce apoptosis through activation of FADD, caspase-8 and the mitochondrial death pathway
- Author
-
von Haefen, Clarissa, Wendt, Jana, Semini, Geo, Sifringer, Marco, Belka, Claus, Radetzki, Silke, Reutter, Werner, Daniel, Peter T., and Danker, Kerstin
- Published
- 2011
- Full Text
- View/download PDF
8. Inositol-C2-PAF down-regulates components of the antigen presentation machinery in a 2D-model of epidermal inflammation
- Author
-
Semini, Geo, Hildmann, Annette, Klein, Andreas, Lucka, Lothar, Schön, Margarete, Schön, Michael P., Shmanai, Vadim, and Danker, Kerstin
- Published
- 2014
- Full Text
- View/download PDF
9. Novel Adhesive Nanocarriers Based on Mussel-Inspired Polyglycerols for the Application onto Mucosal Tissues.
- Author
-
Rajes, Keerthana, Nölte, Peer, Yapto, Cynthia V., Danker, Kerstin, Dommisch, Henrik, and Haag, Rainer
- Subjects
MUCOUS membranes ,NANOCARRIERS ,STAINS & staining (Microscopy) ,ADHESIVES ,CATECHOL ,ORAL mucosa - Abstract
A synthetic route for adhesive core-multishell (CMS) nanocarriers for application to the oral mucosa was established using mussel-inspired catechol moieties. The three CMS nanocarriers with 8%, 13%, and 20% catechol functionalization were evaluated for loading capacity using Nile red, showing an overall loading of 1 wt%. The ability of Nile red loaded and functionalized nanocarriers to bind to a moist mucosal surface was tested in two complementary adhesion assays under static and dynamic conditions using monolayers of differentiated gingival keratinocytes. Adhesion properties of functionalized nanocarriers were compared to the adhesion of the non-functionalized nanocarrier. In both assays, the CMS nanocarrier functionalized with 8% catechol exhibited the strongest adhesion compared to its catechol-free counterpart and the CMS nanocarriers functionalized with 13% and 20% catechol. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. Key role of [[alpha].sub.1][[beta].sub.1]-integrin in the activation of PI3-kinase-Akt by flow (shear stress) in resistance arteries
- Author
-
Loufrani, Laurent, Retailleau, Kevin, Bocquet, Arnaud, Dumont, 0dile, Danker, Kerstin, Louis, Huguette, Lacolley, Patrick, and Henrion, Daniel
- Subjects
Cardiovascular diseases -- Risk factors ,Cardiovascular diseases -- Genetic aspects ,Cardiovascular diseases -- Care and treatment ,Cardiovascular diseases -- Research ,Nitric oxide -- Dosage and administration ,Protein kinases -- Health aspects ,Protein kinases -- Research ,Biological sciences - Abstract
Resistance arteries are the site of the earliest manifestations of many cardiovascular and metabolic diseases. Flow (shear stress) is the main physiological stimulus for the endothelium through the activation of vasodilatory pathways generating flow-mediated dilation (FMD). The role of FMD in local blood flow control and angiogenesis is well established, and alterations in FMD are early markers of cardiovascular disorders, [[alpha].sub.1]-Integrin, which has a role in angiogenesis, could be involved in FMD. FMD was studied in mesenteric resistance arteries (MRA) isolated in arteriographs. The role of [[alpha].sub.1] -integrins in FMD was tested with selective antibodies and mice lacking the gene encoding for [[alpha].sub.1]integrins. Both anti-[[alpha].sub.1] blocking antibodies and genetic deficiency in [[alpha].sub.1]-integrin in mice ([[alpha].sub.1.sup.-/-]) inhibited FMD without affecting receptor-mediated (acetylcholine) endothelium-dependent dilation or endothelium-independent dilation (sodium nitroprusside). Similarly, vastconstrictor tone (myogenic tone and phenylephrine-induced contraction) was not affected. In MRA phosphorylated Akt and phosphatidylinositol 3-kinase (PI3-kinase) were significantly lower in [[alpha].sub.1.sup.-/-] mice than in [[alpha].sub.+/+] mice, although total Akt and endothelial nitric oxide synthase (eNOS) were not affected. Pharmacological blockade of PI3-kinaseAkt pathway with LY-294002 inhibited FMD. This inhibitory effect of LY-294002 was significantly lower in [[alpha].sub.1-/-] mice than in [[alpha].sub.1.sup.+/+] mice. Thus [[alpha].sub.1]-integrin has a key role in flow (shear stress)-dependent vasodilation in resistance arteries by transmitting the signal to eNOS through activation of PI3-kinase and Akt. Because of the central role of flow (shear stress) activation of the endothelium in vascular disorders, this finding opens new perspectives in the pathophysiology of the microcirculation and provides new therapeutic targets. myogenic tone; nitric oxide; [N.sup.G]-nitro-L-arginine methyl ester; Akt; [[alpha].sub.1]-integrin; transgenic mice; mechanotransduction
- Published
- 2008
11. Biochemical engineering of the acyl side chain of sialic acids stimulates integrin-dependent adhesion of HL60 cells to fibronectin
- Author
-
Villavicencio-Lorini, Pablo, Laabs, Stephan, Danker, Kerstin, Reutter, Werner, and Horstkorte, Rüdiger
- Published
- 2002
- Full Text
- View/download PDF
12. The novel synthetic ether lipid inositol–C2–PAF inhibits phosphorylation of the tyrosine kinases Src and FAK independent of integrin activation in transformed skin cells
- Author
-
Semini, Geo, Hildmann, Annette, Reissig, Hans–Ulrich, Reutter, Werner, and Danker, Kerstin
- Published
- 2011
- Full Text
- View/download PDF
13. Glycosidated phospholipids: uncoupling of signalling pathways at the plasma membrane
- Author
-
Danker, Kerstin, Reutter, Werner, and Semini, Geo
- Published
- 2010
- Full Text
- View/download PDF
14. Role of the α1 integrin cytoplasmic tail in the formation of focal complexes, actin organization, and in the control of cell migration
- Author
-
Smerling, Christiane, Tang, Kerstin, Hofmann, Werner, and Danker, Kerstin
- Published
- 2007
- Full Text
- View/download PDF
15. Pharmacological SARM1 inhibition protects axon structure and function in paclitaxel-induced peripheral neuropathy.
- Author
-
Bosanac, Todd, Hughes, Robert O, Engber, Thomas, Devraj, Rajesh, Brearley, Andrew, Danker, Kerstin, Young, Kenneth, Kopatz, Jens, Hermann, Melanie, Berthemy, Antoine, Boyce, Susan, Bentley, Jonathan, and Krauss, Raul
- Subjects
PACLITAXEL ,SCIATIC nerve injuries ,PERIPHERAL nervous system ,PERIPHERAL neuropathy ,CENTRAL nervous system ,SCIATIC nerve ,LABORATORY mice ,PROTEINS ,RESEARCH ,NEURONS ,CELL culture ,ANIMAL experimentation ,RESEARCH methodology ,CYTOSKELETAL proteins ,ANTINEOPLASTIC agents ,MEDICAL cooperation ,EVALUATION research ,COMPARATIVE studies ,DOSE-effect relationship in pharmacology ,STEM cells ,EPITHELIAL cells ,THIAZOLES ,MICE ,PHARMACODYNAMICS ,CHEMICAL inhibitors - Abstract
Axonal degeneration is an early and ongoing event that causes disability and disease progression in many neurodegenerative disorders of the peripheral and central nervous systems. Chemotherapy-induced peripheral neuropathy (CIPN) is a major cause of morbidity and the main cause of dose reductions and discontinuations in cancer treatment. Preclinical evidence indicates that activation of the Wallerian-like degeneration pathway driven by sterile alpha and TIR motif containing 1 (SARM1) is responsible for axonopathy in CIPN. SARM1 is the central driver of an evolutionarily conserved programme of axonal degeneration downstream of chemical, inflammatory, mechanical or metabolic insults to the axon. SARM1 contains an intrinsic NADase enzymatic activity essential for its pro-degenerative functions, making it a compelling therapeutic target to treat neurodegeneration characterized by axonopathies of the peripheral and central nervous systems. Small molecule SARM1 inhibitors have the potential to prevent axonal degeneration in peripheral and central axonopathies and to provide a transformational disease-modifying treatment for these disorders. Using a biochemical assay for SARM1 NADase we identified a novel series of potent and selective irreversible isothiazole inhibitors of SARM1 enzymatic activity that protected rodent and human axons in vitro. In sciatic nerve axotomy, we observed that these irreversible SARM1 inhibitors decreased a rise in nerve cADPR and plasma neurofilament light chain released from injured sciatic nerves in vivo. In a mouse paclitaxel model of CIPN we determined that Sarm1 knockout mice prevented loss of axonal function, assessed by sensory nerve action potential amplitudes of the tail nerve, in a gene-dosage-dependent manner. In that CIPN model, the irreversible SARM1 inhibitors prevented loss of intraepidermal nerve fibres induced by paclitaxel and provided partial protection of axonal function assessed by sensory nerve action potential amplitude and mechanical allodynia. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
16. Protein kinase C phosphorylates and regulates UDP- N-acetylglucosamine-2-epimerase/ N-acetylmannosamine kinase
- Author
-
Horstkorte, Rüdiger, Nöhring, Sabine, Danker, Kerstin, Effertz, Karin, Reutter, Werner, and Lucka, Lothar
- Published
- 2000
- Full Text
- View/download PDF
17. IL-1β strengthens the physical barrier in gingival epithelial cells.
- Author
-
Stolte, Kim Natalie, Pelz, Carsten, Yapto, Cynthia V., Raguse, Jan-Dirk, Dommisch, Henrik, and Danker, Kerstin
- Subjects
EPITHELIAL cells ,ORAL mucosa ,TIGHT junctions ,PERIODONTITIS ,GINGIVA - Abstract
Periodontitis is one of the most common oral diseases worldwide and is caused by a variety of interactions between oral bacteria and the host. Here, pathogens induce inflammatory host responses that cause the secretion of proinflammatory cytokines such as IL-1β, IL-6, and IL-8 by oral epithelial cells. In various systems, it has been shown that inflammation compromises physical barriers, which enables bacteria to invade the tissue. In this study, we investigated the barrier properties of the oral mucosa under physiological and inflamed conditions. For this purpose, we assessed the influence of IL-1β on the transepithelial electrical resistance and in particular on tight junctions in vitro in human stratified squamous epithelium models. Indirect immunofluorescence and western blot analyses were performed to investigate localization and expression of tight junction proteins in primary gingival cells, immortalized gingival cells and native gingiva. Furthermore, the TEER of gingival keratinocytes was assessed. The results showed that IL-1β led to strengthening of the gingival keratinocyte barrier. This was demonstrated by an increase in TEER, the upregulation of TJ proteins, and an increase in the formation of TJ strands. The IL-1β-mediated upregulation of occludin was prevented by the NF-κB inhibitor BAY 11–7085. These observations provide insights into host responses in the early stages of periodontal disease and offer information about TJ formation in human gingival epithelial cells under physiological and inflammatory conditions. Comprehensive knowledge of the physical barrier during inflammation may help in developing strategies to effectively target the inflammatory barrier to improve the bioavailability of drugs for the treatment of periodontitis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
18. Modified phospholipids: From detergents towards small molecular response modifiers.
- Author
-
Hildmann, Annette and Danker, Kerstin
- Subjects
- *
PHOSPHOLIPIDS , *DETERGENTS , *CLEANING compounds , *CELL membranes , *BIOLOGICAL membranes - Abstract
Natural living cell membrane phospholipids undergo rapid and continuous turnover that provides essential signalling pathways controlling cell survival. Derived from (lyso)phosphatidylcholine, alkylphopspholipids (APL) were synthesized as metabolically stable analogues 50 years ago. The nature of the chemical structure of APLs allows them to be inserted into membranes easily and partition into the membrane bilayers according to the degree of unsaturation of phospholipid alkyl chains. In an effort to overcome the severe side effects of existing anti-tumour drugs, novel APLs with variations in alkyl side chain length, glycerol backbone, ester versus ether bonds, and different polar headgroups were developed to combine high anti-proliferative capacity with reduced cytotoxicity. The platelet activating factor (PAF) is a natural alkylphospholipid. Substituting the sn-2 position of platelet activating factor with an ether linked C2 spacer coupled to inositol created Inositol-C2-PAF. The effects of Inositol-C2-PAF can be divided into short-term and long-term effects. Short-term effects include the inhibition of phosphorylation events, resulting in inhibition of cell proliferation and reduced cell migration. Long-term effects of Inositol-C2-PAF, which are characterised by changes in gene expression, include up-regulation of biological processes linked to cell differentiation or system development. Inspired by the natural phospholipid platelet activating factor (PAF) derivatives are shown, that intercalate in plasma membranes and at sub-toxic concentrations disturb plasma membrane microdomain composition and/or intracellular responses. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
19. Soluble adenylyl cyclase accounts for high basal cCMP and cUMP concentrations in HEK293 and B103 cells.
- Author
-
Hasan, Alan, Danker, Kerstin Y., Wolter, Sabine, Bähre, Heike, Kaever, Volkhard, and Seifert, Roland
- Subjects
- *
BICARBONATE ions , *GENETIC regulation , *FORSKOLIN , *CANCER cells , *CYCLIC adenylic acid , *CYCLIC guanylic acid ,ADENYLATE cyclase inhibitors - Abstract
Highlights: [•] Bicarbonate effectively regulates basal cCMP and cUMP concentrations. [•] The sAC inhibitor KH7 reduces bicarbonate-stimulated cCMP and cUMP. [•] The mAC activator forskolin increases cAMP, but not cGMP, cCMP and cUMP. [•] sGC plays no major role in the regulation of basal cNMPs in HEK293 and B103 cells. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
20. Nucleotidyl cyclase activity of soluble guanylyl cyclase in intact cells.
- Author
-
Bähre, Heike, Danker, Kerstin Y., Stasch, Johannes-Peter, Kaever, Volkhard, and Seifert, Roland
- Subjects
- *
GUANYLATE cyclase , *CELL physiology , *CYCLIC-AMP-dependent protein kinase , *CGMP-dependent protein kinase , *CELLULAR control mechanisms , *INOSINE - Abstract
Highlights: [•] The presence of cCMP and cUMP in intact cells is unambiguously documented. [•] Soluble guanlyl cyclase generates cCMP and cUMP in intact cells. [•] cGMP, cCMP and cUMP show different regulatory patterns. [•] Mn2+ is a physiological cofactor for soluble guanylyl cyclase. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
21. Synthetic glycosidated phospholipids induce apoptosis through activation of FADD, caspase-8 and the mitochondrial death pathway.
- Author
-
Haefen, Clarissa, Wendt, Jana, Semini, Geo, Sifringer, Marco, Belka, Claus, Radetzki, Silke, Reutter, Werner, Daniel, Peter, and Danker, Kerstin
- Abstract
poptosis is modulated by extrinsic and intrinsic signaling pathways through the formation of the death receptor-mediated death-inducing signaling complex (DISC) and the mitochondrial-derived apoptosome, respectively. Ino-C2-PAF, a novel synthetic phospholipid shows impressive antiproliferative and apoptosis-inducing activity. Little is known about the signaling pathway through which it stimulates apoptosis. Here, we show that this drug induces apoptosis through proteins of the death receptor pathway, which leads to an activation of the intrinsic apoptotic pathway. Apoptosis induced by Ino-C2-PAF and its glucosidated derivate, Glc-PAF, was dependent on the DISC components FADD and caspase-8. This can be inhibited in FADD−/− and caspase-8−/− cells, in which the breakdown of the mitochondrial membrane potential, release of cytochrome c and activation of caspase-9, -8 and -3 do not occur. In addition, the overexpression of crmA, c-Flip or dominant negative FADD as well as treatment with the caspase-8 inhibitor z-IETD-fmk protected against Ino-C2-PAF-induced apoptosis. Apoptosis proceeds in the absence of CD95/Fas-ligand expression and is independent of blockade of a putative death-ligand/receptor interaction. Furthermore, apoptosis cannot be inhibited in CD95/Fas−/− Jurkat cells. Expression of Bcl-2 in either the mitochondria or the endoplasmic reticulum (ER) strongly inhibited Ino-C2-PAF- and Glc-PAF-induced apoptosis. In conclusion, Ino-C2-PAF and Glc-PAF trigger a CD95/Fas ligand- and receptor-independent atypical DISC that relies on the intrinsic apoptotic pathway via the ER and the mitochondria. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
22. Key role of α1β1-integrin in the activation of PI3-kinase-Akt by flow (shear stress) in resistance arteries.
- Author
-
Loufrani, Laurent, Retailleau, Kevin, Bocquet, Arnaud, Dumont, Odile, Danker, Kerstin, Louis, Huguette, Lacolley, Patrick, and Henrion, Daniel
- Subjects
INTEGRINS ,CELL adhesion molecules ,GLYCOPROTEINS ,ARTERIES ,CARDIOVASCULAR diseases - Abstract
Resistance arteries are the site of the earliest manifestations of many cardiovascular and metabolic diseases. Flow (shear stress) is the main physiological stimulus for the endothelium through the activation of vasodilatory pathways generating flow-mediated dilation (FMD). The role of FMD in local blood flow control and angiogenesis is well established, and alterations in FMD are early markers of cardiovascular disorders. a, - Integrin, which has a role in angiogenesis, could be involved in FMD. FMD was studied in mesenteric resistance arteries (MRA) isolated in arteriographs. The role of a,-integrins in FMD was tested with selective antibodies and mice lacking the gene encoding for a, - integrins. Both anti-a1 blocking antibodies and genetic deficiency in a1-integrin in mice (a,~) inhibited FMD without affecting receptor-mediated (acetylcholine) endothelium-dependent dilation or endo- thelium-independent dilation (sodium nitroprusside). Similarly, vasoconstrictor tone (myogenic tone and phenylephrine-induced contraction) was not affected. In MRA phosphorylated Akt and phosphatidylinositol 3-kinase (P13-kinase) were significantly lower in a1~ mice than in a1~ mice, although total Akt and endothelial nitric oxide synthase (eNOS) were not affected. Pharmacological blockade of P13-kinase- Akt pathway with LY-294002 inhibited FMD. This inhibitory effect of LY-294002 was significantly lower in a,~ mice than in a1'~ mice. Thus a,-integrin has a key role in flow (shear stress)-dependent vasodilation in resistance arteries by transmitting the signal to eNOS through activation of P13-kinase and Akt. Because of the central role of flow (shear stress) activation of the endothelium in vascular disorders, this finding opens new perspectives in the pathophysiology of the microcirculation and provides new therapeutic targets. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
23. The Ether Lipid Inositol-C2-PAF is a Potent Inhibitor of Cell Proliferation in HaCaT Cells.
- Author
-
Fischer, Annette, Müller, Dieter, Zimmermann-Kordmann, Martin, Kleuser, Burkhard, Mickeleit, Michael, Laabs, Stephan, Löwe, Werner, Cantagrel, Frédéric, Reutter, Werner, and Danker, Kerstin
- Published
- 2006
- Full Text
- View/download PDF
24. Biochemical engineering of the <f>N</f>-acyl side chain of sialic acid leads to increased calcium influx from intracellular compartments and promotes differentiation of HL60 cells
- Author
-
Horstkorte, Rüdiger, Rau, Kirstin, Laabs, Stephan, Danker, Kerstin, and Reutter, Werner
- Subjects
CARBOHYDRATES ,ADHESION ,BIOCHEMICAL engineering ,BIOTECHNOLOGY - Abstract
Sialylation of glycoconjugates is essential for mammalian cells. Sialic acid is synthesized in the cytosol from
N -acetylmannosamine by several consecutive steps. UsingN -propanoylmannosamine, a novel precursor of sialic acid, we are able to incorporate unnatural sialic acids with a prolongedN -acyl side chain (e.g.,N -propanoylneuraminic acid) into glycoconjugates taking advance of the cellular sialylation machinery. Here, we report that unnatural sialylation of HL60-cells leads to an increased release of intracellular calcium after application of thapsigargin, an inhibitor of SERCA Ca2+ -ATPases. Furthermore, this increased intracellular calcium concentration leads to an increased adhesion to fibronectin. Finally, we observed an increase of the lectin galectin-3, a marker of monocytic differentiation of HL60-cells. [Copyright &y& Elsevier]- Published
- 2004
- Full Text
- View/download PDF
25. C-Cam-meditated adhesion leads to an outside-in dephosphorylation signal.
- Author
-
Lucka, Lothar, Budt, Matthias, Cichocka, Iwona, Danker, Kerstin, Horstkorte, Rudiger, and Reutter, Werner
- Subjects
CELL adhesion ,PHOSPHORYLATION - Abstract
Examines the effect of cell-cell adhesion molecule (C-CAM) to the phosphorylation of the cytoplasmic domain of C-CAM. Reduction in C-CAM[sub L] phosphorylation; Dephosphorylation of C-CAM by antibody-induced clustering in the plasma membrane; Indication of C-CAM-mediated outside-in signaling induced by cell-cell adhesion.
- Published
- 1999
- Full Text
- View/download PDF
26. Tissue expression and amino acid sequence of murine UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase.
- Author
-
Horstkorte, Rudiger, Nohring, Sabine, Wiechens, Nicola, Schwartzkopf, Martina, Danker, Kerstin, Reutter, Werner, and Lucka, Lothar
- Subjects
NEURAMINIDASE ,GLYCOCONJUGATES ,AMINO acid sequence - Abstract
Examines the expression of neuraminic acids on glycoconjugates. Involvement of the acids in a variety of biological functions; Analysis of the complete amino acid sequence of the mouse UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase; Generation of the tissues with a maximal expression in the liver.
- Published
- 1999
- Full Text
- View/download PDF
27. Primary structure and expression analysis of human UDP-N-acetyl-glucosamine-2-epimerase/N-acetylmannosamine kinase, the bifunctional enzyme in neuraminic acid biosynthesis
- Author
-
Lucka, Lothar, Krause, Matthias, Danker, Kerstin, Reutter, Werner, and Horstkorte, Rüdiger
- Subjects
Tissue expression ,Neuraminic acid biosynthesis ,UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase - Abstract
N-Acetylneuraminic acid is a main constituent of glycoproteins and gangliosides. In many membrane-bound receptors it is the target for external stimuli. The key enzyme for its biosynthesis is the bifunctional enzyme UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase, catalysing the first two steps of the biosynthesis in the cytosol. The rat enzyme was previously isolated and characterised. In this report we present the corresponding human cDNA sequence, compare it with the primary structure of the rodent enzyme, and report the analysis of its expression in different human tissues and cell lines.
- Full Text
- View/download PDF
28. Carcinoembryonic antigen-related cell-cell adhesion molecule C-CAM is greatly increased in serum and urine of rats with liver diseases
- Author
-
Lucka, Lothar, Sel, Serdar, Danker, Kerstin, Horstkorte, Rüdiger, and Reutter, Werner
- Published
- 1998
- Full Text
- View/download PDF
29. Impact of alkylphospholipids on the gene expression profile of HaCaT cells.
- Author
-
Semini, Geo, Klein, Andreas, and Danker, Kerstin
- Abstract
New alkylphospholipids (APLs) that are structurally derived from the platelet-activating factor (PAF) are promising candidates for anticancer treatment. After incorporation into cell membranes, APLs are able to interfere with a wide variety of key enzymes implicated in cell growth, motility, invasion, and apoptosis. In addition to the prototype 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (edelfosine), we presented a novel group of APLs, the glycosidated phospholipids that efficiently inhibit cell proliferation. Two members of this group, Ino-C2-PAF and Glc-PAF, display high efficacy and low cytotoxicity in immortalized nontumorigenic skin keratinocyte cell line, HaCaT. This study investigated the impact of APLs on the transcription of the whole genome.Using Agilent complementary DNA microarray technology, we compared global gene expression profiles of HaCaT cells treated with edelfosine, Ino-C2-PAF, or Glc-PAF with the profile of control cells.We found that Ino-C2-PAF has the strongest influence on gene expression in comparison with edelfosine and Glc-PAF. Gene Ontology analysis showed that differentially expressed transcripts regulated by the three APLs are mainly implicated in lipid metabolism, lipid biosynthesis, cell differentiation, cell development, and ion homeostasis. Nevertheless, the most remarkable finding is represented by the ability of Ino-C2-PAF to downregulate a broad spectrum of genes associated with the regulation of the innate and acquired immune response and of genes linked to inflammation.These results identify Ino-C2-PAF as the most effective APL used in this study. Therefore, Ino-C2-PAF might be a promising compound for further studies that concentrate on the inhibition of inflammatory responses. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
30. IL-1β promotes transendothelial migration of PBMCs by upregulation of the FN/α5β1 signalling pathway in immortalised human brain microvascular endothelial cells.
- Author
-
Labus, Josephine, Wöltje, Kerstin, Stolte, Kim Natalie, Häckel, Sonja, Kim, Kwang Sik, Hildmann, Annette, and Danker, Kerstin
- Subjects
- *
CELL migration , *LEUCOCYTES , *ENDOTHELIAL cells , *GENE expression , *INTEGRINS - Abstract
Abstract Neuroinflammation is often associated with pathological changes in the function of the blood-brain barrier (BBB) caused by disassembly of tight and adherens junctions that under physiological conditions are important for the maintenance of the BBB integrity. Consequently, in inflammation the BBB becomes dysfunctional, facilitating leukocyte traversal of the barrier and accumulation of immune cells within the brain. The extracellular matrix (ECM) also contributes to BBB integrity but the significance of the main ECM receptors, the β 1 integrins also expressed on endothelial cells, is less well understood. To evaluate whether β 1 integrin function is affected during inflammation and impacts barrier function, we used a transformed human brain microvascular endothelial cell (THBMEC)-based Interleukin 1β (IL-1β)-induced inflammatory in vitro BBB model. We demonstrate that IL-1β increases cell-matrix adhesion and induces a redistribution of active β 1 integrins to the basal surface. In particular, binding of α 5 β 1 integrin to its ligand fibronectin is enhanced and α 5 β 1 integrin-dependent signalling is upregulated. Additionally, localisation of the tight junction protein claudin-5 is altered. Blockade of the α 5 β 1 integrin reduces the IL-1β-induced transendothelial migration of peripheral blood mononuclear cells (PBMCs). These data imply that IL-1β-induced inflammation not only destabilizes tight junctions but also increases α 5 β 1 integrin-dependent cell-matrix adhesion to fibronectin. Graphical abstract fx1 Highlights • IL-1β-induced inflammation of THBMECs increases cell-matrix adhesion. • Active β 1 integrins are redistributed under inflammatory conditions. • IL-1β activates the FN/α 5 β 1 integrin/FAK/Src-signalling pathway. • Blocking the α 5 integrin subunit reduces IL-1β-induced transendothelial migration. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. Inositoylated Platelet-Activating Factor (Ino-C2-PAF) Modulates Dynamic Lymphocyte-Endothelial Cell Interactions and Alleviates Psoriasis-Like Skin Inflammation in Two Complementary Mouse Models.
- Author
-
Forkel, Susann, Schön, Margarete, Hildmann, Annette, Claßen, Anna, John, Swen-Malte, Danker, Kerstin, and Schön, Michael P
- Subjects
- *
PLATELET activating factor , *LYMPHOCYTES , *ENDOTHELIAL cells , *CELL communication , *SKIN inflammation , *LABORATORY mice - Abstract
Psoriasis, a tumor necrosis factor alpha (TNFα)-governed inflammatory disorder with prominent dysregulation of cutaneous vascular functions, has evolved into a model disorder for studying anti-inflammatory therapies. We present experimental in vitro and in vivo data on 1-O-octadecyl-2-O-(2-(myo-inositolyl)-ethyl)-sn-glycero-3-(R/S)-phosphatidyl-choline (Ino-C2-PAF), the lead compound of a class of synthetic glycosylated phospholipids, in anti-inflammatory therapy. Ino-C2-PAF strongly induced apoptosis only in TNFα-stimulated, but not in untreated human vascular endothelial cells. Moreover, TNFα-induced endothelial adhesion molecules that mediated the rolling and firm adhesion of leukocytes (vascular cell adhesion protein-1 (VCAM-1), E-selectin, and ICAM-1) were selectively downregulated by Ino-C2-PAF. Similarly, expression of L-selectin, VCAM-1 receptor α4β1 integrin , and lymphocyte function-associated antigen-1 on human peripheral blood mononuclear cells was reduced without induction of apoptosis. Functionally, these changes were accompanied by significant impairment of rolling and adhesion of human peripheral blood lymphocytes on TNFα-activated endothelial cells in a dynamic flow chamber system. When the therapeutic potential of Ino-C2-PAF was assessed in two complementary mouse models of psoriasis, K5.hTGFβ1 transgenic and JunB/c-Jun-deficient mice, Ino-C2-PAF led to significant alleviation of the clinical symptoms and normalized the pathological cutaneous changes including vascularization. There were no overt adverse effects. These findings suggested that Ino-C2-PAF is a potential candidate in the therapy of inflammatory skin diseases that include abnormal vascular functions. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Interleukin-1β induces an inflammatory response and the breakdown of the endothelial cell layer in an improved human THBMEC-based in vitro blood–brain barrier model.
- Author
-
Labus, Josephine, Häckel, Sonja, Lucka, Lother, and Danker, Kerstin
- Subjects
- *
INTERLEUKIN-1 , *INFLAMMATION , *ENDOTHELIAL cells , *BLOOD-brain barrier , *IN vitro studies , *CELL lines - Abstract
Highlights: [•] A blood–brain barrier model based on the THBMEC cell line was improved. [•] A novel inflammatory blood–brain barrier model was established. [•] IL-1β induced a strong inflammatory response in this model. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
33. Role of the α1 integrin cytoplasmic tail in the formation of focal complexes, actin organization, and in the control of cell migration
- Author
-
Smerling, Christiane, Tang, Kerstin, Hofmann, Werner, and Danker, Kerstin
- Subjects
- *
CELL migration , *CYTOPLASM , *CELLS , *CYTOLOGICAL research - Abstract
Abstract: Integrins play a key role in cellular motility; an essential process for embryonic development and tissue morphogenesis, and also for pathological processes such as tumor cell invasion and metastasis. Recently, we showed that the cytoplasmic tail of integrin α1 regulates the formation of focal complexes, F-actin cytoskeleton reorganization, and migration. We now report that the α1 tail directly engages in collagen IV-mediated migration by regulation of the small GTPase Rac1. Deletion variants of the α1 integrin differ in their ability to activate Rac1. Constitutively active Rac1 rescues motility in otherwise immotile cells expressing a truncated α1 integrin without any cytoplasmic tail. In these cells, levels of GTP-Rac1 are constitutively elevated, but kept non-functional in the cytoplasm. The conserved GFFKR motif is sufficient to convey Rac1 activation, but downregulates the amount of GTP-Rac1 in the absence of the α1-specific sequence PLKKKMEK. This sequence is also required for the recruitment of PI3K to focal adhesions following Rac1 activation. Our results demonstrate that the short α1 cytoplasmic tail is crucial for Rac1 activation and PI3K localization, which in turn results in cytoskeletal rearrangement and subsequent migration. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
34. Keratinocyte differentiation and signal transduction is defined by antipodal expression of two homologous membrane glycoproteins, Trop-1 and Trop-2
- Author
-
Schön, Margarete, Klein, C.Eberhard, Alberti, Saverio, Danker, Kerstin, Ruzicka, Thomas, and Schön, Michael P.
- Published
- 1998
- Full Text
- View/download PDF
35. Topical Application of Dexamethasone-Loaded Core-Multishell Nanocarriers Against Oral Mucosal Inflammation.
- Author
-
Yapto CV, Rajes K, Inselmann A, Staufenbiel S, Stolte KN, Witt M, Haag R, Dommisch H, and Danker K
- Abstract
Topical treatment of oral inflammatory diseases is challenging due to the intrinsic physicochemical barriers of the mucosa and the continuous flow of saliva, which dilute drugs and limit their bioavailability. Nanocarrier technology can be an innovative approach to circumvent these problems and thus improve the efficacy of topical drug delivery to the mucosa. Core-multishell (CMS) nanocarriers are putative delivery systems with high biocompatibility and the ability to adhere to and penetrate the oral mucosa. Ester-based CMS nanocarriers release the anti-inflammatory compound dexamethasone (Dx) more efficiently than a conventional cream. Mussel-inspired functionalization of a CMS nanocarrier with catechol further improves the adhesion of the nanocarrier and may enhance the efficacy of the loaded drugs. In the present study, the properties of the ester-based CMS 10-E-15-350 nanocarrier (CMS-NC) are further evaluated in comparison to the catechol-functionalized variant (CMS-C
0.08 ). While the mucoadhesion of CMS-NC is inhibited by saliva, CMS-C0.08 exhibits better mucoadhesion in the presence of saliva. Due to the improved adhesion properties, CMS-C0.08 loaded with dexamethasone (Dx-CMS-C0.08 ) shows a better anti-inflammatory effect than Dx-CMS-NC when applied dynamically. These results highlight the superiority of CMS-C0.08 over CMS-NC as an innovative drug delivery system (DDS) for the treatment of oral mucosal diseases., (© 2024 The Author(s). Macromolecular Bioscience published by Wiley‐VCH GmbH.)- Published
- 2024
- Full Text
- View/download PDF
36. Anti-inflammatory IL-8 Regulation via an Advanced Drug Delivery System at the Oral Mucosa.
- Author
-
Witt M, Cherri M, Ferraro M, Yapto C, Vogel K, Schmidt L, Haag R, Danker K, and Dommisch H
- Subjects
- Animals, Swine, Anti-Inflammatory Agents pharmacology, Anti-Inflammatory Agents therapeutic use, Polymers pharmacology, Drug Delivery Systems, Interleukin-8, Mouth Mucosa
- Abstract
Oral inflammatory diseases are highly prevalent in the worldwide population. Topical treatment of inflammation is challenging due to dilution effects of saliva and crevicular fluid. Thus, there is a great medical need to develop smart anti-inflammatory drug delivery systems for mucosa treatment. We compared two promising anti-inflammatory dendritic poly(glycerol-caprolactone) sulfate (dPGS-PCL) polymers for their applicability to the oral mucosa. Using an ex vivo porcine tissue model, cell monolayers, and full-thickness 3D oral mucosal organoids, the polymers were evaluated for muco-adhesion, penetration, and anti-inflammatory properties. The biodegradable dPGS-PCL
97 polymers adhered to and penetrated the masticatory mucosa within seconds. No effects on metabolic activity and cell proliferation were found. dPGS-PCL97 revealed a significant downregulation of pro-inflammatory cytokines with a clear preference for IL-8 in cell monolayers and mucosal organoids. Thus, dPGS-PCL97 exhibits excellent properties for topical anti-inflammatory therapy, suggesting new therapeutic avenues in the treatment of oral inflammatory diseases.- Published
- 2023
- Full Text
- View/download PDF
37. Pharmacological SARM1 inhibition protects axon structure and function in paclitaxel-induced peripheral neuropathy.
- Author
-
Bosanac T, Hughes RO, Engber T, Devraj R, Brearley A, Danker K, Young K, Kopatz J, Hermann M, Berthemy A, Boyce S, Bentley J, and Krauss R
- Subjects
- Animals, Antineoplastic Agents, Phytogenic toxicity, Armadillo Domain Proteins deficiency, Armadillo Domain Proteins genetics, Axons metabolism, Cells, Cultured, Cytoskeletal Proteins deficiency, Cytoskeletal Proteins genetics, Dose-Response Relationship, Drug, HEK293 Cells, Humans, Induced Pluripotent Stem Cells drug effects, Induced Pluripotent Stem Cells metabolism, Mice, Mice, Knockout, Peripheral Nervous System Diseases genetics, Peripheral Nervous System Diseases metabolism, Thiazoles pharmacology, Armadillo Domain Proteins antagonists & inhibitors, Axons drug effects, Cytoskeletal Proteins antagonists & inhibitors, Paclitaxel toxicity, Peripheral Nervous System Diseases chemically induced, Peripheral Nervous System Diseases drug therapy, Thiazoles therapeutic use
- Abstract
Axonal degeneration is an early and ongoing event that causes disability and disease progression in many neurodegenerative disorders of the peripheral and central nervous systems. Chemotherapy-induced peripheral neuropathy (CIPN) is a major cause of morbidity and the main cause of dose reductions and discontinuations in cancer treatment. Preclinical evidence indicates that activation of the Wallerian-like degeneration pathway driven by sterile alpha and TIR motif containing 1 (SARM1) is responsible for axonopathy in CIPN. SARM1 is the central driver of an evolutionarily conserved programme of axonal degeneration downstream of chemical, inflammatory, mechanical or metabolic insults to the axon. SARM1 contains an intrinsic NADase enzymatic activity essential for its pro-degenerative functions, making it a compelling therapeutic target to treat neurodegeneration characterized by axonopathies of the peripheral and central nervous systems. Small molecule SARM1 inhibitors have the potential to prevent axonal degeneration in peripheral and central axonopathies and to provide a transformational disease-modifying treatment for these disorders. Using a biochemical assay for SARM1 NADase we identified a novel series of potent and selective irreversible isothiazole inhibitors of SARM1 enzymatic activity that protected rodent and human axons in vitro. In sciatic nerve axotomy, we observed that these irreversible SARM1 inhibitors decreased a rise in nerve cADPR and plasma neurofilament light chain released from injured sciatic nerves in vivo. In a mouse paclitaxel model of CIPN we determined that Sarm1 knockout mice prevented loss of axonal function, assessed by sensory nerve action potential amplitudes of the tail nerve, in a gene-dosage-dependent manner. In that CIPN model, the irreversible SARM1 inhibitors prevented loss of intraepidermal nerve fibres induced by paclitaxel and provided partial protection of axonal function assessed by sensory nerve action potential amplitude and mechanical allodynia., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2021
- Full Text
- View/download PDF
38. Novel insights in the dysfunction of human blood-brain barrier after glycation.
- Author
-
Hussain M, Bork K, Gnanapragassam VS, Bennmann D, Jacobs K, Navarette-Santos A, Hofmann B, Simm A, Danker K, and Horstkorte R
- Subjects
- Antigens, Neoplasm metabolism, Blood-Brain Barrier pathology, Cells, Cultured, Endothelial Cells pathology, Humans, Interleukin-6 metabolism, Interleukin-8 metabolism, Mitogen-Activated Protein Kinases metabolism, Occludin metabolism, Zonula Occludens-1 Protein metabolism, Blood-Brain Barrier metabolism, Endothelial Cells metabolism, Glycation End Products, Advanced metabolism
- Abstract
The blood-brain barrier (BBB) provides a dynamic and complex interface consisting of endothelial cells, pericytes and astrocytes, which are embedded in a collagen and fibronectin-rich basement membrane. This complex structure restricts the diffusion of small hydrophilic solutes and macromolecules as well as the transmigration of leukocytes into the brain. It has been shown that carbonyl stress followed by the formation of advanced glycation endproducts (AGE=glycation) interfere with the BBB integrity and function. Here, we present data that carbonyl stress induced by methylglyoxal leads to glycation of endothelial cells and the basement membrane, which interferes with the barrier-function and with the expression of RAGE, occludin and ZO-1. Furthermore, methylglyoxal induced carbonyl stress promotes the expression of the pro-inflammatory interleukins IL-6 and IL-8. In summary, this study provides new insights into the relationship between AGE formation by carbonyl stress and brain microvascular endothelial barrier dysfunction., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
39. Glycosidated phospholipids - a promising group of anti-tumour lipids.
- Author
-
Semini G, Hildmann A, von Haefen C, and Danker K
- Subjects
- Animals, Antineoplastic Agents chemistry, Antineoplastic Agents metabolism, Antineoplastic Agents therapeutic use, Apoptosis drug effects, Cell Adhesion drug effects, Cell Differentiation drug effects, Cell Movement drug effects, Cell Proliferation drug effects, Extracellular Matrix drug effects, Extracellular Matrix physiology, Gene Expression drug effects, Glycosylation, Humans, Inositol analogs & derivatives, Inositol chemistry, Inositol metabolism, Inositol pharmacology, Inositol therapeutic use, Neoplasms immunology, Neoplasms pathology, Phospholipids chemistry, Phospholipids metabolism, Phospholipids therapeutic use, Platelet Activating Factor analogs & derivatives, Platelet Activating Factor chemistry, Platelet Activating Factor metabolism, Platelet Activating Factor pharmacology, Platelet Activating Factor therapeutic use, Antineoplastic Agents pharmacology, Neoplasms drug therapy, Phospholipids pharmacology
- Abstract
Synthetic alkylphospholipids (APLs), exhibit similarity to the platelet-activating factor (PAF). These compounds have antiproliferative effects on tumour cells and can therefore be regarded as a new class of drugs. Unlike classic cytostatic agents, synthetic alkylphospholipids do not interfere with the DNA or the mitotic spindle apparatus. Instead, due to their aliphatic character, alkylphospholipids accumulate in cell membranes, where they have an impact on lipid metabolism and lipid-dependent signalling pathways which leads to inhibition of proliferation and induction of apoptosis in malignant cells. Normal cells remain unaffected by these compounds. Glycosidated phospholipids, are a novel class of alkylphospholipids, in which carbohydrates or carbohydrate-related molecules are introduced in the chemical lead of PAF. These hybrid alkylphospholipids also exhibit anti-proliferative capacity. Furthermore, members of this subfamily also modulate cell adhesion, differentiation, apoptosis and migration of tumour cells. Among the members of this group, Inositol-C2-platelet-activating factor (Ino-C2-PAF) is the most effective compound developed so far. Recently, we also showed that Ino-C2-PAF exhibited the strongest impact on the gene expression levels of immortalised keratinocytes in comparison to edelfosine and another glycosidated alkylphospholipid, Glucose-platelet-activating factor (Glc-PAF). Furthermore, Ino-C2-PAF reduced the expression of genes encoding proteins associated with inflammation and the innate and acquired immune responses.
- Published
- 2014
- Full Text
- View/download PDF
40. Structure/activity relationships of (M)ANT- and TNP-nucleotides for inhibition of rat soluble guanylyl cyclase α1β1.
- Author
-
Dove S, Danker KY, Stasch JP, Kaever V, and Seifert R
- Subjects
- Adenylyl Cyclase Inhibitors, Adenylyl Cyclases chemistry, Animals, Guanylate Cyclase chemistry, Hydrogen Bonding, Hydrophobic and Hydrophilic Interactions, Molecular Docking Simulation, Protein Binding, Protein Conformation, Protein Subunits antagonists & inhibitors, Protein Subunits chemistry, Rats, Receptors, Cytoplasmic and Nuclear chemistry, Recombinant Proteins chemistry, Soluble Guanylyl Cyclase, Structure-Activity Relationship, Guanylate Cyclase antagonists & inhibitors, Nitro Compounds chemistry, Purine Nucleotides chemistry, Pyrimidine Nucleotides chemistry, Receptors, Cytoplasmic and Nuclear antagonists & inhibitors, ortho-Aminobenzoates chemistry
- Abstract
Soluble guanylyl cyclase (sGC) plays an important role in cardiovascular function and catalyzes formation of cGMP. sGC is activated by nitric oxide and allosteric stimulators and activators. However, despite its therapeutic relevance, the regulatory mechanisms of sGC are still incompletely understood. A major reason for this situation is that no crystal structures of active sGC have been resolved so far. An important step toward this goal is the identification of high-affinity ligands that stabilize an sGC conformation resembling the active, "fully closed" state. Therefore, we examined inhibition of rat sGCα1β1 by 38 purine- and pyrimidine-nucleotides with 2,4,6,-trinitrophenyl and (N-methyl)anthraniloyl substitutions at the ribosyl moiety and compared the data with that for the structurally related membranous adenylyl cyclases (mACs) 1, 2, 5 and the purified mAC catalytic subunits VC1:IIC2. TNP-GTP [2',3'-O-(2,4,6-trinitrophenyl)-GTP] was the most potent sGCα1β1 inhibitor (Ki, 10.7 nM), followed by 2'-MANT-3'-dATP [2'-O-(N-methylanthraniloyl)-3'-deoxy-ATP] (Ki, 16.7 nM). Docking studies on an sGCαcat/sGCβcat model derived from the inactive heterodimeric crystal structure of the catalytic domains point to similar interactions of (M)ANT- and TNP-nucleotides with sGCα1β1 and mAC VC1:IIC2. Reasonable binding modes of 2'-MANT-3'-dATP and bis-(M)ANT-nucleotides at sGC α1β1 require a 3'-endo ribosyl conformation (versus 3'-exo in 3'-MANT-2'-dATP). Overall, inhibitory potencies of nucleotides at sGCα1β1 versus mACs 1, 2, 5 correlated poorly. Collectively, we identified highly potent sGCα1β1 inhibitors that may be useful for future crystallographic and fluorescence spectroscopy studies. Moreover, it may become possible to develop mAC inhibitors with selectivity relative to sGC.
- Published
- 2014
- Full Text
- View/download PDF
41. Interleukin (IL)-23 mediates Toxoplasma gondii-induced immunopathology in the gut via matrixmetalloproteinase-2 and IL-22 but independent of IL-17.
- Author
-
Muñoz M, Heimesaat MM, Danker K, Struck D, Lohmann U, Plickert R, Bereswill S, Fischer A, Dunay IR, Wolk K, Loddenkemper C, Krell HW, Libert C, Lund LR, Frey O, Hölscher C, Iwakura Y, Ghilardi N, Ouyang W, Kamradt T, Sabat R, and Liesenfeld O
- Subjects
- Animals, Female, Intestine, Small immunology, Matrix Metalloproteinase 9 physiology, Mice, Mice, Inbred C57BL, Piperazines pharmacology, Pyrimidines pharmacology, Toxoplasmosis, Animal immunology, Interleukin-22, Interleukin-17 physiology, Interleukin-23 physiology, Interleukins physiology, Intestine, Small pathology, Matrix Metalloproteinase 2 physiology, Toxoplasma pathogenicity
- Abstract
Peroral infection with Toxoplasma gondii leads to the development of small intestinal inflammation dependent on Th1 cytokines. The role of Th17 cells in ileitis is unknown. We report interleukin (IL)-23-mediated gelatinase A (matrixmetalloproteinase [MMP]-2) up-regulation in the ileum of infected mice. MMP-2 deficiency as well as therapeutic or prophylactic selective gelatinase blockage protected mice from the development of T. gondii-induced immunopathology. Moreover, IL-23-dependent up-regulation of IL-22 was essential for the development of ileitis, whereas IL-17 was down-regulated and dispensable. CD4(+) T cells were the main source of IL-22 in the small intestinal lamina propria. Thus, IL-23 regulates small intestinal inflammation via IL-22 but independent of IL-17. Gelatinases may be useful targets for treatment of intestinal inflammation.
- Published
- 2009
- Full Text
- View/download PDF
42. Role of the alpha(1) integrin cytoplasmic tail in the formation of focal complexes, actin organization, and in the control of cell migration.
- Author
-
Smerling C, Tang K, Hofmann W, and Danker K
- Subjects
- Actins ultrastructure, Amino Acid Sequence, Animals, CHO Cells, Cricetinae, Cricetulus, Cytoskeleton metabolism, Enzyme Activation, Phosphatidylinositol 3-Kinases metabolism, Signal Transduction physiology, rac1 GTP-Binding Protein genetics, rac1 GTP-Binding Protein metabolism, Actins metabolism, Cell Movement physiology, Integrin alpha1 chemistry, Integrin alpha1 genetics, Integrin alpha1 metabolism, Protein Structure, Tertiary
- Abstract
Integrins play a key role in cellular motility; an essential process for embryonic development and tissue morphogenesis, and also for pathological processes such as tumor cell invasion and metastasis. Recently, we showed that the cytoplasmic tail of integrin alpha(1) regulates the formation of focal complexes, F-actin cytoskeleton reorganization, and migration. We now report that the alpha(1) tail directly engages in collagen IV-mediated migration by regulation of the small GTPase Rac1. Deletion variants of the alpha(1) integrin differ in their ability to activate Rac1. Constitutively active Rac1 rescues motility in otherwise immotile cells expressing a truncated alpha(1) integrin without any cytoplasmic tail. In these cells, levels of GTP-Rac1 are constitutively elevated, but kept non-functional in the cytoplasm. The conserved GFFKR motif is sufficient to convey Rac1 activation, but downregulates the amount of GTP-Rac1 in the absence of the alpha(1)-specific sequence PLKKKMEK. This sequence is also required for the recruitment of PI3K to focal adhesions following Rac1 activation. Our results demonstrate that the short alpha(1) cytoplasmic tail is crucial for Rac1 activation and PI3K localization, which in turn results in cytoskeletal rearrangement and subsequent migration.
- Published
- 2007
- Full Text
- View/download PDF
43. Integrin alpha3beta1 interacts with I1PP2A/lanp and phosphatase PP1.
- Author
-
Mutz D, Weise C, Mechai N, Hofmann W, Horstkorte R, Brüning G, and Danker K
- Subjects
- Animals, Blotting, Western methods, Calbindins, Cell Differentiation drug effects, Cell Differentiation physiology, Chromatography, Affinity methods, Gene Expression physiology, Green Fluorescent Proteins metabolism, Immunohistochemistry methods, Neurites physiology, PC12 Cells, Peptide Fragments metabolism, Peptide Mapping methods, Potassium Chloride pharmacology, Protein Binding physiology, Rats, Recombinant Fusion Proteins metabolism, S100 Calcium Binding Protein G metabolism, Transfection, Atrial Natriuretic Factor metabolism, Integrin alpha3beta1 metabolism, Phosphoric Monoester Hydrolases metabolism
- Abstract
Integrin alpha3beta1 is a receptor for the extracellular matrix component laminin 5. To elucidate possible signaling pathways induced by integrin alpha3beta1, we looked for proteins that interact with the cytoplasmic part of the alpha3A integrin subunit. We identified several multifunctional proteins by affinity chromatography and subsequent MALDI-TOF-MS and focused on the inhibitor 1 of serine/threonine phosphatase PP2A (I1PP2A, synonym: lanp) which also plays a role during the development of the mouse cerebellum. I1PP2A/lanp colocalizes with the alpha3A integrin subunit in differentiated PC12 cells in the cell body and in neurites as well as in Purkinje cells of mouse cerebellum. Overexpression of GFP-I1PP2A/lanp in PC12 cells leads to markedly reduced neurite length on laminin 5 after induction with nerve growth factor. By affinity chromatography the protein phosphatase PP1 can also be identified as a alpha3A/cyto-binding protein. PP1 and integrin alpha3beta1 can be pulled down by GST-I1PP2A/lanp from cell lysates of differentiated and undifferentiated PC12 cells. The phosphatase binds to the cytoplasmic membrane-proximal conserved GFFKR motif of the alpha integrin subunit, whereas I1PP2A/lanp requires a longer sequence for binding. PP1 but not PP2A is able to dephosphorylate precipitated integrin alpha3beta1 in vitro. Furthermore, PP1 releases phosphate from T1046 of phosphopeptides that mimic the phosphorylation consensus sequence in the cytoplasmic part of the alpha3A integrin subunit. These data suggest that I1PP2A/lanp forms a complex with PP1 and the alpha3A integrin subunit and might possibly regulate the phosphorylation status of integrin alpha3beta1 and/or integrin downstream targets.
- Published
- 2006
- Full Text
- View/download PDF
44. The cytoplasmic tail of the alpha3 integrin subunit promotes neurite outgrowth in PC12 cells.
- Author
-
Mechai N, Wenzel M, Koch M, Lucka L, Horstkorte R, Reutter W, and Danker K
- Subjects
- Animals, Antibodies pharmacology, Blotting, Western methods, Carcinoma pathology, Cell Adhesion Molecules immunology, Cell Adhesion Molecules pharmacology, Cell Differentiation drug effects, Cell Differentiation physiology, Cell Line, Tumor, Cytoplasm drug effects, Enzyme Inhibitors pharmacology, Flow Cytometry methods, Fluorescent Antibody Technique methods, Gene Expression Regulation physiology, Humans, PC12 Cells, Protein Structure, Tertiary, RNA, Messenger biosynthesis, Rats, Receptors, Interleukin-2 metabolism, Reverse Transcriptase Polymerase Chain Reaction methods, Transfection methods, Kalinin, Cytoplasm metabolism, Integrin alpha3beta1 physiology, Neurites physiology
- Abstract
Binding of integrins to proteins of the extracellular matrix (ECM) provides structural and signaling information for biological processes such as cell proliferation, migration, neurite outgrowth, and differentiation. Integrins represent a family of heterodimeric transmembrane cell surface receptors. Besides connecting the ECM with the cytoskeleton, integrins also induce various signaling pathways in response to ligand binding. Integrin ligation leads to cytoplasmic protein-protein interactions requiring both integrin cytoplasmic tails. These sequences are initiation points for focal adhesion formation and subsequent signal transduction cascades. In this study, we addressed the question of whether the short cytoplasmic tail of the alpha(3) integrin subunit of alpha(3)beta(1) integrin is required for alpha(3)beta(1) integrin-dependent processes. For this purpose, cDNA representing the extracellular and transmembrane domain of the interleukin 2 receptor (IL2R) alpha subunit and the cytoplasmic sequence of the alpha(3) integrin subunit was transfected into PC12 cells. Autonomous expression of the cytoplasmic alpha(3) tail does not affect attachment but leads to inhibition of neuronal differentiation on laminin 5. This indicates that the cytoplasmic alpha(3) sequence is not required for cell attachment but is necessary for long-term adhesion and for the reorganization of the cytoskeleton that precedes neuronal differentiation. Inhibition of neurite outgrowth by chimeric IL2R-alpha(3) can be rescued by treatment of transfected cells with the pharmacological inhibitor Y27632, which inhibits the RhoA downstream effector Rho kinase alpha.
- Published
- 2005
- Full Text
- View/download PDF
45. Glucosamine-glycerophospholipids that activate cell-matrix adhesion and migration.
- Author
-
Bartolmäs T, Heyn T, Mickeleit M, Fischer A, Reutter W, and Danker K
- Subjects
- Antineoplastic Agents pharmacology, Antineoplastic Agents toxicity, Cell Line, Cell Proliferation drug effects, Dose-Response Relationship, Drug, Glucosamine pharmacology, Glucosamine toxicity, Glycerophospholipids pharmacology, Glycerophospholipids toxicity, Glycolipids pharmacology, Glycolipids toxicity, Humans, Structure-Activity Relationship, Antineoplastic Agents chemical synthesis, Cell Adhesion drug effects, Cell Movement drug effects, Glucosamine analogs & derivatives, Glucosamine chemical synthesis, Glycerophospholipids chemical synthesis, Glycolipids chemical synthesis
- Abstract
Two new analogues derived from the platelet activating factor (PAF), containing glucosamine instead of the acetyl group, were synthesized, and their effect on the human keratinocyte cell line HaCaT was evaluated with respect to cytotoxicity, proliferation, adhesion, and migration. Starting with (R)-1,2-isopropylideneglycerol (3), the glycosylation acceptor 1-O-octadecyl-3-O-tert-butyldimethylsilyl-sn-glycerol (6) was synthesized in three steps. Glycosylation of 6 with the already known O-(3,4,6-tri-O-acetyl-2-deoxy-2-dimethylmaleimido-beta-D-glycopyranosyl)trichloracetimidate gave 1-O-octadecyl-2-O-(3',4',6'-tri-O-acetyl-2'-deoxy-2'-dimethylmaleimido-beta-D-glucopyranosyl)-3-O-tert-butyldimethylsilyl-sn-glycerol (7). After removing the (tert-butyldimethyl)silyl (TBDMS) group with FeCl3x6H2O, phosphoryl choline was introduced, yielding [1-O-octadecyl-2-O-(2'-deoxy-2'-dimethylmaleimido-beta-D-glucopyranosyl)-sn-glycero(3)]phosphorylcholine (2) (glucosimide-PAF). pH controlled cleavage of the amino protection group gave [1-O-octadecyl-2-O-(2'-deoxy-2'-amino-beta-D-glucopyranosyl)-sn-glycero(3)]phosphorylcholine hydrochloride (1) (glucosamine-PAF). 2 inhibited proliferation of HaCaT cells by 26% at nontoxic concentrations, while 1 increased the proliferation rate by 30% at low concentrations. At higher concentrations, both compounds showed cytotoxic properties with LD50 = 30 micromol/L (1) and LD50 = 5-6 micromol/L (2). Both 1 and 2 were potent promoters of cell adhesion and migration of HaCaT cells.
- Published
- 2005
- Full Text
- View/download PDF
46. Biochemical engineering of the N-acyl side chain of sialic acid leads to increased calcium influx from intracellular compartments and promotes differentiation of HL60 cells.
- Author
-
Horstkorte R, Rau K, Laabs S, Danker K, and Reutter W
- Subjects
- Acylation, Calcium-Transporting ATPases antagonists & inhibitors, Enzyme Inhibitors pharmacology, Glycoconjugates metabolism, HL-60 Cells, Humans, Thapsigargin pharmacology, Calcium metabolism, Cell Differentiation physiology, N-Acetylneuraminic Acid metabolism
- Abstract
Sialylation of glycoconjugates is essential for mammalian cells. Sialic acid is synthesized in the cytosol from N-acetylmannosamine by several consecutive steps. Using N-propanoylmannosamine, a novel precursor of sialic acid, we are able to incorporate unnatural sialic acids with a prolonged N-acyl side chain (e.g., N-propanoylneuraminic acid) into glycoconjugates taking advance of the cellular sialylation machinery. Here, we report that unnatural sialylation of HL60-cells leads to an increased release of intracellular calcium after application of thapsigargin, an inhibitor of SERCA Ca2+-ATPases. Furthermore, this increased intracellular calcium concentration leads to an increased adhesion to fibronectin. Finally, we observed an increase of the lectin galectin-3, a marker of monocytic differentiation of HL60-cells.
- Published
- 2004
- Full Text
- View/download PDF
47. Phospholipase Cgamma binds alpha1beta1 integrin and modulates alpha1beta1 integrin-specific adhesion.
- Author
-
Vossmeyer D, Hofmann W, Löster K, Reutter W, and Danker K
- Subjects
- Amino Acid Motifs, Amino Acid Sequence, Animals, Blotting, Western, CHO Cells, Cell Adhesion, Collagen chemistry, Cricetinae, Cytoplasm metabolism, Dose-Response Relationship, Drug, Electrophoresis, Polyacrylamide Gel, Enzyme Inhibitors pharmacology, Estrenes pharmacology, Immunoglobulin G metabolism, Integrin alpha1beta1, Laminin chemistry, Models, Biological, Molecular Sequence Data, PC12 Cells, Peptides chemistry, Phosphodiesterase Inhibitors pharmacology, Phosphoinositide-3 Kinase Inhibitors, Phospholipase C gamma, Phosphorylation, Precipitin Tests, Protein Binding, Protein Structure, Tertiary, Pyrrolidinones pharmacology, Rats, Time Factors, Transfection, Tyrosine chemistry, Integrins chemistry, Integrins metabolism, Isoenzymes chemistry, Isoenzymes metabolism, Type C Phospholipases chemistry, Type C Phospholipases metabolism
- Abstract
Integrin adhesion receptors have been implicated in bidirectional signal transduction. The dynamic regulation of integrin affinity and avidity as well as post-ligand effects involved in outside-in signaling depends on the interaction of integrins with cytoskeletal and signaling proteins. In this study, we attempted to identify cytoplasmic binding partners of alpha(1)beta(1) integrin. We were able to show that cell adhesion to alpha(1)beta(1)-specific substrates results in the association of phospholipase Cgamma (PLCgamma) with the alpha(1)beta(1) integrin independent of PLCgamma tyrosine phosphorylation. Using peptide-binding assays, the membrane proximal sequences within the alpha(1)beta(1) integrin subunits were identified as binding sites for PLCgamma. In particular, the conserved sequence of beta(1) subunit binds the enzyme very efficiently. Because purified PLCgamma also binds the integrin peptides, binding seems to be direct. Inhibition of PLC by leads to reduced cell adhesion on alpha(1)beta(1)-specific substrates. Cells lacking the conserved domain of the alpha(1) subunit fail to respond to the PLC inhibition, indicating that this domain is necessary for PLC-dependent adhesion modulation of alpha(1)beta(1) integrin.
- Published
- 2002
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.