The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Friedrich Marks - One of the best experts on this subject based on the ideXlab platform.
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rottlerin a novel Protein Kinase Inhibitor
Biochemical and Biophysical Research Communications, 1994Co-Authors: Michael Gschwendt, Walter Kittstein, H J Muller, K Kielbassa, R Zang, Gabriele Rincke, Friedrich MarksAbstract:Rottlerin, a compound from Mallotus philippinensis, is shown to inhibit Protein Kinases with some specificity for PKC. To some extent, the novel Inhibitor is able to differentiate between PKC isoenzymes, with IC50 values for PKC delta of 3-6 microM, PKC alpha,beta,gamma of 30-42 microM and PKC epsilon,eta,zeta of 80-100 microM. Inhibition of PKC appears, at least in part, to be due to a competition between rottlerin and ATP. Among the Protein Kinases tested, only CaM-Kinase III is suppressed by rottlerin as effectively as PKC delta. The chemical structure of rottlerin might serve as a basis for the development of novel Inhibitors with improved selectivity for a distinct PKC isoenzyme, such as PKC delta, or for CaM-Kinase III.
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Elongation factor-2 Kinase: effective inhibition by the novel Protein Kinase Inhibitor rottlerin and relative insensitivity towards staurosporine.
FEBS letters, 1994Co-Authors: Michael Gschwendt, Walter Kittstein, Friedrich MarksAbstract:The elongation factor-2 (eEF-2) is selectively phosphorylated by the eEF-2 Kinase (calmodulin-dependent Kinase III). This phosphorylation can be inhibited by calmodulin antagonists, such as CGS 9343B (IC5o = 4 μM). The novel Protein Kinase Inhibitor rottlerin is shown to suppress eEF-2 phosphorylation with an IC50 of 5.3 μM. By contrast, the eEF-2 Kinase is rather resistant towards the potent but non-selective Protein Kinase Inhibitor staurosporine (IC50> 50 μM) and thus can be differentiated from most other Protein Kinases that are suppressed by staurosporine in the nM range.
Hidenobu Tanihara - One of the best experts on this subject based on the ideXlab platform.
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Potential Role of Rho-Associated Protein Kinase Inhibitor Y-27632 in Glaucoma Filtration Surgery
2013Co-Authors: Megumi Honjo, Hidenobu Tanihara, Takanori Kameda, Nagahisa Yoshimura, Takahiro Kawaji, Makoto AraieAbstract:PURPOSE. To investigate the role of Y-27632, a specific Inhibitor of Rho-associated Protein Kinase (ROCK) in regulating human Tenon fibroblast (HTF) activities including proliferation, adhesion, contraction, migratory response, and myofibroblast transdifferentiation. Effects of Y-27632 on prevention of postoperative scar formation were also examined in a rabbit model of glaucoma filtration surgery. METHODS. After treatment of HTFs with Y-27632, cell toxicity, proliferation, migration, adhesion, and contraction were studied. The cytoskeleton and �-smooth muscle actin (�-SMA) expression were examined via immunohistochemistry. In vivo studies in Japanese white rabbits consisted of a full-thickness sclerostomy followed in the 7-day postoperative period by topical application of Y-27632. Intraocular pressure, morphologic changes in bleb features, and histology of surgical site
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the effect of rho associated Protein Kinase Inhibitor on monkey schlemm s canal endothelial cells
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Takanori Kameda, Toshihiro Inoue, Masaru Inatani, Tomokazu Fujimoto, Megumi Honjo, Nanako Kasaoka, Miyuki Inouemochita, Nagahisa Yoshimura, Hidenobu TaniharaAbstract:Purpose To investigate the effect of a specific Inhibitor of Rho-associated Protein Kinase, Y-27632, on monkey Schlemm's canal endothelial (SCE) cells. Methods SCE cells were isolated from cynomolgus monkey eyes. The effects of Y-27632 on aqueous outflow facility were evaluated using enucleated monkey eyes and a constant-pressure perfusion system. The effect of Y-27632 on the barrier function of the confluent SCE-cell monolayer was evaluated by measuring transendothelial electrical resistance (TEER) and fluorescein permeability. Y-27632-induced changes in the intracellular localization of ZO-1, claudin-5, β-catenin, pan-cadherin, and filamentous actin (F-actin) were examined by immunofluorescence. Gene-expression changes induced by Y-27632 were analyzed with microarray, and the functional categories of changed genes were identified by gene ontology analysis. The concentrations of intracellular calcium ions were estimated using Fluo-4/AM and a fluorescence microscope system. Results Y-27632 significantly increased the outflow facility and the number of associated giant vacuoles, decreased TEER of the SCE-cell monolayer, and increased the transendothelial flux of fluorescein. Y-27632 disrupted ZO-1 and claudin-5 expression in a confluent SCE-cell monolayer. Among 12,544 genes, Y-27632 treatment increased the expression of 57 genes and decreased the expression of 15 genes. Gene ontology analysis revealed that changed genes were related to various cellular functions, including regulation of calcium ion transport into the cytosol. Y-27632 partially diminished the A23187-induced increase in intracellular calcium ions. Conclusions Y-27632 increased the permeability of the SCE-cell monolayer in association with disruption of the tight junction, F-actin depolymerization, and changes in various cell functions, including calcium transfer.
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effects of y 39983 a selective rho associated Protein Kinase Inhibitor on blood flow in optic nerve head in rabbits and axonal regeneration of retinal ganglion cells in rats
Current Eye Research, 2011Co-Authors: Hideki Tokushige, Mitsunori Waki, Yoshiko Takayama, Hidenobu TaniharaAbstract:Purpose: To investigate the effects of Y-39983, a selective Rho-associated coiled coil-forming Protein Kinase Inhibitor, on blood flow in the optic nerve head (ONH) in rabbits and axonal regeneration of retinal ganglion cells (RGCs) in rats.Methods: Blood flow in ONH was measured by the laser speckle method after topical administration of 0.05% Y-39983 solution or its vehicle in rabbit eyes. To investigate the effects of Y-39983 on axonal regeneration of RGCs, RGCs purified from rat eyes were cultured with or without 10 μM Y-39983 and morphologically observed by phase-contrast microscopy. Moreover, the effects of intravitreal administration of Y-39983 were evaluated using an in vivo model of axotomized RGCs in peripheral nerve-grafted rats.Results: Topical administration of 0.05% Y-39983 solution significantly increased blood flow in ONH compared with the vehicle group in rabbits. Maximum increase in blood flow in the 0.05% Y-39983 group was 122.84 ± 5.98 % (Mean ± S.E.) at 90 minutes after administration...
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Potential role of Rho-associated Protein Kinase Inhibitor Y-27632 in glaucoma filtration surgery.
Investigative ophthalmology & visual science, 2007Co-Authors: Megumi Honjo, Hidenobu Tanihara, Takanori Kameda, Nagahisa Yoshimura, Takahiro Kawaji, Makoto AraieAbstract:PURPOSE. To investigate the role of Y-27632, a specific Inhibitor of Rho-associated Protein Kinase (ROCK) in regulating human Tenon fibroblast (HTF) activities including proliferation, adhesion, contraction, migratory response, and myofibroblast transdifferentiation. Effects of Y-27632 on prevention of postoperative scar formation were also examined in a rabbit model of glaucoma filtration surgery. METHODS. After treatment of HTFs with Y-27632, cell toxicity, proliferation, migration, adhesion, and contraction were studied. The cytoskeleton and -smooth muscle actin (-SMA) expression were examined via immunohistochemistry. In vivo studies in Japanese white rabbits consisted of a full-thickness sclerostomy followed in the 7-day postoperative period by topical application of Y-27632. Intraocular pressure, morphologic changes in bleb features, and histology of surgical sites were evaluated. RESULTS. Y-27632 had no direct toxicity or significant effects on cell proliferation of HTF. The cell adhesion assay showed that Y-27632 promoted adhesiveness to both fibronectin and collagen type I. Use of Y-27632 significantly inhibited collagen gel contraction and -SMA expression in HTFs. Y-27632 also increased HTF motility. In vivo, Y-27632 inhibited wound healing and fibroproliferation after filtration surgery and significantly improved surgical outcome compared with the vehicle. Histologic examination revealed that blebs in the Y-27632treated group differed from those in the vehicle-treated group in that they lacked significant collagen deposition in the sclerostomy area. CONCLUSIONS. Y-27632 had profound effects on activities of HTFs and was effective in preventing fibroproliferation and scar formation in a rabbit model of glaucoma surgery. A ROCK Inhibitor may be an effective anti-scarring agent after glaucoma filtering surgery. (Invest Ophthalmol Vis Sci. 2007;48: 5549‐5557) DOI:10.1167/iovs.07-0878 T he main cause of failure of glaucoma filtration surgery is postoperative scarring in the filtering bleb. Perioperative administration of antimetabolites such as 5-fluorouracil and mitomycin C (MMC) is effective in limiting the scarring process. However, use of these antiproliferative agents is accom
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Effects of Rho-Associated Protein Kinase Inhibitor Y-27632 on Intraocular Pressure and Outflow Facility
Investigative ophthalmology & visual science, 2001Co-Authors: Megumi Honjo, Hidenobu Tanihara, Shuh Narumiya, Masaru Inatani, Noriaki Kido, Tatsuya Sawamura, Beatrice Y. J. T. Yue, Yoshihito HondaAbstract:Purpose To elucidate the roles of Rho-associated Protein Kinase (ROCK) in regulating intraocular pressure (IOP) and outflow facility in the rabbit eye. Methods A specific ROCK Inhibitor Y-27632 was used. The IOP, the outflow facility, and the pupil diameter were determined before and after the topical, intracameral, or intravitreal administration of Y-27632 in rabbits. Western blot analysis was used to identify specific ROCK isoform in human trabecular meshwork (TM) cells and bovine ciliary muscle (CM) tissues. The cell morphology and distribution of actin filaments and vinculin in TM cells were studied by cell biology techniques. Carbachol (Cch)-induced contraction of isolated bovine CM strips after administration of Y-27632 was measured in a perfusion chamber. Results In rabbit eyes, administration of Y-27632 resulted in a significant decrease in IOP in a dose-dependent manner. An increase of the outflow facility and pupil size dilation was also observed in Y-27632-treated eyes. Western blot analysis revealed the presence of p160ROCK in human TM cells and bovine CM tissues. In cultured human TM cells, exposure to Y-27632 caused retraction and rounding of cell bodies as well as disruption of actin bundles and impairment of focal adhesion formation. Y-27632 in addition inhibited Cch-induced contraction of isolated bovine CM strips. Conclusions Administration of Y-27632 caused a reduction in IOP and an increase in the outflow facility. The in vitro experiments suggest that the IOP-lowering effects of Y-27632 may be related to the altered cellular behavior of TM cells and relaxation of CM contraction. These studies suggest that ROCK Inhibitors may have great potential to be developed for treatment of glaucoma and other ocular diseases.
Megumi Honjo - One of the best experts on this subject based on the ideXlab platform.
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Potential Role of Rho-Associated Protein Kinase Inhibitor Y-27632 in Glaucoma Filtration Surgery
2013Co-Authors: Megumi Honjo, Hidenobu Tanihara, Takanori Kameda, Nagahisa Yoshimura, Takahiro Kawaji, Makoto AraieAbstract:PURPOSE. To investigate the role of Y-27632, a specific Inhibitor of Rho-associated Protein Kinase (ROCK) in regulating human Tenon fibroblast (HTF) activities including proliferation, adhesion, contraction, migratory response, and myofibroblast transdifferentiation. Effects of Y-27632 on prevention of postoperative scar formation were also examined in a rabbit model of glaucoma filtration surgery. METHODS. After treatment of HTFs with Y-27632, cell toxicity, proliferation, migration, adhesion, and contraction were studied. The cytoskeleton and �-smooth muscle actin (�-SMA) expression were examined via immunohistochemistry. In vivo studies in Japanese white rabbits consisted of a full-thickness sclerostomy followed in the 7-day postoperative period by topical application of Y-27632. Intraocular pressure, morphologic changes in bleb features, and histology of surgical site
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the effect of rho associated Protein Kinase Inhibitor on monkey schlemm s canal endothelial cells
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Takanori Kameda, Toshihiro Inoue, Masaru Inatani, Tomokazu Fujimoto, Megumi Honjo, Nanako Kasaoka, Miyuki Inouemochita, Nagahisa Yoshimura, Hidenobu TaniharaAbstract:Purpose To investigate the effect of a specific Inhibitor of Rho-associated Protein Kinase, Y-27632, on monkey Schlemm's canal endothelial (SCE) cells. Methods SCE cells were isolated from cynomolgus monkey eyes. The effects of Y-27632 on aqueous outflow facility were evaluated using enucleated monkey eyes and a constant-pressure perfusion system. The effect of Y-27632 on the barrier function of the confluent SCE-cell monolayer was evaluated by measuring transendothelial electrical resistance (TEER) and fluorescein permeability. Y-27632-induced changes in the intracellular localization of ZO-1, claudin-5, β-catenin, pan-cadherin, and filamentous actin (F-actin) were examined by immunofluorescence. Gene-expression changes induced by Y-27632 were analyzed with microarray, and the functional categories of changed genes were identified by gene ontology analysis. The concentrations of intracellular calcium ions were estimated using Fluo-4/AM and a fluorescence microscope system. Results Y-27632 significantly increased the outflow facility and the number of associated giant vacuoles, decreased TEER of the SCE-cell monolayer, and increased the transendothelial flux of fluorescein. Y-27632 disrupted ZO-1 and claudin-5 expression in a confluent SCE-cell monolayer. Among 12,544 genes, Y-27632 treatment increased the expression of 57 genes and decreased the expression of 15 genes. Gene ontology analysis revealed that changed genes were related to various cellular functions, including regulation of calcium ion transport into the cytosol. Y-27632 partially diminished the A23187-induced increase in intracellular calcium ions. Conclusions Y-27632 increased the permeability of the SCE-cell monolayer in association with disruption of the tight junction, F-actin depolymerization, and changes in various cell functions, including calcium transfer.
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Potential role of Rho-associated Protein Kinase Inhibitor Y-27632 in glaucoma filtration surgery.
Investigative ophthalmology & visual science, 2007Co-Authors: Megumi Honjo, Hidenobu Tanihara, Takanori Kameda, Nagahisa Yoshimura, Takahiro Kawaji, Makoto AraieAbstract:PURPOSE. To investigate the role of Y-27632, a specific Inhibitor of Rho-associated Protein Kinase (ROCK) in regulating human Tenon fibroblast (HTF) activities including proliferation, adhesion, contraction, migratory response, and myofibroblast transdifferentiation. Effects of Y-27632 on prevention of postoperative scar formation were also examined in a rabbit model of glaucoma filtration surgery. METHODS. After treatment of HTFs with Y-27632, cell toxicity, proliferation, migration, adhesion, and contraction were studied. The cytoskeleton and -smooth muscle actin (-SMA) expression were examined via immunohistochemistry. In vivo studies in Japanese white rabbits consisted of a full-thickness sclerostomy followed in the 7-day postoperative period by topical application of Y-27632. Intraocular pressure, morphologic changes in bleb features, and histology of surgical sites were evaluated. RESULTS. Y-27632 had no direct toxicity or significant effects on cell proliferation of HTF. The cell adhesion assay showed that Y-27632 promoted adhesiveness to both fibronectin and collagen type I. Use of Y-27632 significantly inhibited collagen gel contraction and -SMA expression in HTFs. Y-27632 also increased HTF motility. In vivo, Y-27632 inhibited wound healing and fibroproliferation after filtration surgery and significantly improved surgical outcome compared with the vehicle. Histologic examination revealed that blebs in the Y-27632treated group differed from those in the vehicle-treated group in that they lacked significant collagen deposition in the sclerostomy area. CONCLUSIONS. Y-27632 had profound effects on activities of HTFs and was effective in preventing fibroproliferation and scar formation in a rabbit model of glaucoma surgery. A ROCK Inhibitor may be an effective anti-scarring agent after glaucoma filtering surgery. (Invest Ophthalmol Vis Sci. 2007;48: 5549‐5557) DOI:10.1167/iovs.07-0878 T he main cause of failure of glaucoma filtration surgery is postoperative scarring in the filtering bleb. Perioperative administration of antimetabolites such as 5-fluorouracil and mitomycin C (MMC) is effective in limiting the scarring process. However, use of these antiproliferative agents is accom
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Effects of Rho-Associated Protein Kinase Inhibitor Y-27632 on Intraocular Pressure and Outflow Facility
Investigative ophthalmology & visual science, 2001Co-Authors: Megumi Honjo, Hidenobu Tanihara, Shuh Narumiya, Masaru Inatani, Noriaki Kido, Tatsuya Sawamura, Beatrice Y. J. T. Yue, Yoshihito HondaAbstract:Purpose To elucidate the roles of Rho-associated Protein Kinase (ROCK) in regulating intraocular pressure (IOP) and outflow facility in the rabbit eye. Methods A specific ROCK Inhibitor Y-27632 was used. The IOP, the outflow facility, and the pupil diameter were determined before and after the topical, intracameral, or intravitreal administration of Y-27632 in rabbits. Western blot analysis was used to identify specific ROCK isoform in human trabecular meshwork (TM) cells and bovine ciliary muscle (CM) tissues. The cell morphology and distribution of actin filaments and vinculin in TM cells were studied by cell biology techniques. Carbachol (Cch)-induced contraction of isolated bovine CM strips after administration of Y-27632 was measured in a perfusion chamber. Results In rabbit eyes, administration of Y-27632 resulted in a significant decrease in IOP in a dose-dependent manner. An increase of the outflow facility and pupil size dilation was also observed in Y-27632-treated eyes. Western blot analysis revealed the presence of p160ROCK in human TM cells and bovine CM tissues. In cultured human TM cells, exposure to Y-27632 caused retraction and rounding of cell bodies as well as disruption of actin bundles and impairment of focal adhesion formation. Y-27632 in addition inhibited Cch-induced contraction of isolated bovine CM strips. Conclusions Administration of Y-27632 caused a reduction in IOP and an increase in the outflow facility. The in vitro experiments suggest that the IOP-lowering effects of Y-27632 may be related to the altered cellular behavior of TM cells and relaxation of CM contraction. These studies suggest that ROCK Inhibitors may have great potential to be developed for treatment of glaucoma and other ocular diseases.
Michael Gschwendt - One of the best experts on this subject based on the ideXlab platform.
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rottlerin a novel Protein Kinase Inhibitor
Biochemical and Biophysical Research Communications, 1994Co-Authors: Michael Gschwendt, Walter Kittstein, H J Muller, K Kielbassa, R Zang, Gabriele Rincke, Friedrich MarksAbstract:Rottlerin, a compound from Mallotus philippinensis, is shown to inhibit Protein Kinases with some specificity for PKC. To some extent, the novel Inhibitor is able to differentiate between PKC isoenzymes, with IC50 values for PKC delta of 3-6 microM, PKC alpha,beta,gamma of 30-42 microM and PKC epsilon,eta,zeta of 80-100 microM. Inhibition of PKC appears, at least in part, to be due to a competition between rottlerin and ATP. Among the Protein Kinases tested, only CaM-Kinase III is suppressed by rottlerin as effectively as PKC delta. The chemical structure of rottlerin might serve as a basis for the development of novel Inhibitors with improved selectivity for a distinct PKC isoenzyme, such as PKC delta, or for CaM-Kinase III.
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Elongation factor-2 Kinase: effective inhibition by the novel Protein Kinase Inhibitor rottlerin and relative insensitivity towards staurosporine.
FEBS letters, 1994Co-Authors: Michael Gschwendt, Walter Kittstein, Friedrich MarksAbstract:The elongation factor-2 (eEF-2) is selectively phosphorylated by the eEF-2 Kinase (calmodulin-dependent Kinase III). This phosphorylation can be inhibited by calmodulin antagonists, such as CGS 9343B (IC5o = 4 μM). The novel Protein Kinase Inhibitor rottlerin is shown to suppress eEF-2 phosphorylation with an IC50 of 5.3 μM. By contrast, the eEF-2 Kinase is rather resistant towards the potent but non-selective Protein Kinase Inhibitor staurosporine (IC50> 50 μM) and thus can be differentiated from most other Protein Kinases that are suppressed by staurosporine in the nM range.
Solomon S. Solomon - One of the best experts on this subject based on the ideXlab platform.
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Paradoxical regulation of SP1 transcription factor by glucagon
Endocrinology, 2002Co-Authors: Chithra Keembiyehetty, Antonio Martinez-hernandez, Rosalind Pitpitan Candelaria, Gipsy Majumdar, Rajendra Raghow, Solomon S. SolomonAbstract:Insulin is a potent regulator of Sp1 transcription factor. To examine if glucagon, which usually antagonizes insulin, regulates Sp1, we assessed the levels of Sp1 by Western blotting from H-411E cells exposed to glucagon with or without insulin. Glucagon alone (1.5 × 10−9 to 1.5 × 10−5 m) stimulated Sp1 accumulation but inhibited insulin’s (10,000 μU/ml) stimulatory effect on Sp1. We also assessed the effect of TNF-α, wortmannin, a PI3K Inhibitor, and cAMP-dependent Protein Kinase Inhibitor on Sp1 accumulation. While TNF-α (5 ng/ml) blocked insulin-stimulated Sp1, it failed to block stimulation of Sp1 by glucagon (1.5 × 10−5 m). Similarly, wortmannin inhibited insulin- but not glucagon-stimulated Sp1, whereas Protein Kinase Inhibitor had an opposite effect. Thus, insulin acts primarily via PI3K, and glucagon apparently stimulates through a cAMP-dependent pathway. Insulin increased the staining intensity of Sp1 seen exclusively in the nuclei of H-411E cells. Sp1 was demonstrable in both nucleus and cytopla...
