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Novel Inhibitors (novel + inhibitor)
Selected AbstractsProstaglandin E2 -Mediated Anabolic Effect of a Novel Inhibitor of Phosphodiesterase 4, XT-611, in the In Vitro Bone Marrow Culture,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2003Ken-Ichi Miyamoto Abstract The mechanism of osteoblast formation by a novel PDE4 inhibitor, XT-611, was studied in the in vitro bone marrow culture system. The compound potentiated the osteoblast differentiation through accumulation of cyclic AMP after autocrine stimulation of EP4 receptor by PGE2 in pro-osteoblastic cells. Introduction: We previously reported that inhibitors of phosphodiesterase (PDE)4 isoenzyme increase osteoblast formation in an in vitro bone marrow culture system and inhibit bone loss in animal osteoporosis models. Here we investigated the mechanism of the effect of a novel PDE4 inhibitor, 3,4-dipropyl-4,5,7,8-tetrahydro-3H -imidazo[1,2- i]-purin-5-one (XT-611), on osteoblast formation in the in vitro bone marrow culture system. Materials and Methods: Rodent bone marrow cells were cultured in the presence of 0.2 mM ascorbic acid phosphate ester, 1 mM ,-glycerophosphate, and 10 nM dexamethasone for 10 days. Drug treatments were done for 24 h on day 3 of culture. Results: PDE4 inhibitors, including XT-611, but not PDE3 and PDE5 inhibitors, increased mineralized nodule formation in rat and mouse bone marrow cell cultures. During culture of the bone marrow cells, prostaglandin E2 (PGE2) production increased with a peak on day 4, but the increase was completely inhibited by indomethacin, an unselective cyclo-oxygenase (COX) inhibitor. Spontaneous and XT-611-induced mineralized-nodule formation was also inhibited by indomethacin and COX-2 inhibitors, in a similar potential. Alkaline phosphatase-positive nodule formation in the absence or presence of XT-611 was inhibited by an antagonist of EP4 receptor, AH23848B, and synergistically potentiated by 11-deoxy-PGE1, but it was not influenced by other EP antagonists and agonists examined. The expression of PDE4 and EP4 mRNAs was observed in bone marrow cells. The effect of XT-611 was also confirmed to involve an increase of cyclic AMP and the cyclic AMP-dependent protein kinase pathway. Conclusion: These results suggest that PGE2 stimulates differentiation of osteoblast progenitor cells through the EP4 receptor in an autocrine manner, and the PDE4 inhibitor potentiates the differentiation by inhibiting hydrolysis of cyclic AMP in the cells. [source] S14-95, a Novel Inhibitor of the JAK/STAT Pathway from a Penicillium Species.CHEMINFORM, Issue 41 2003Gerhard Erkel Abstract For Abstract see ChemInform Abstract in Full Text. [source] Novel Inhibitors of Alkaline Phosphatase Suppress Vascular Smooth Muscle Cell Calcification,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2007Sonoko Narisawa Abstract We report three novel inhibitors of the physiological pyrophosphatase activity of alkaline phosphatase and show that these compounds are capable of reducing calcification in two models of vascular calcification (i.e., they suppress in vitro calcification by cultured Enpp1,/, VSMCs and they inhibit the increased pyrophosphatase activity in a rat aortic model). Introduction: Genetic ablation of tissue-nonspecific alkaline phosphatase (TNALP) leads to accumulation of the calcification inhibitor inorganic pyrophosphate (PPi). TNALP deficiency ameliorates the hypermineralization phenotype in Enpp1,/, and ank/ank mice, two models of osteoarthritis and soft tissue calcification. We surmised that the pharmacological inhibition of TNALP pyrophosphatase activity could be used to prevent/suppress vascular calcification. Materials and Methods: Comprehensive chemical libraries were screened to identify novel drug-like compounds that could inhibit TNALP pyrophosphatase function at physiological pH. We used these novel compounds to block calcification by cultured vascular smooth muscle cells (VSMCs) and to inhibit the upregulated pyrophosphatase activity in a rat aortic calcification model. Results: Using VSMC cultures, we determined that Enpp1,/, and ank/ank VSMCs express higher TNALP levels and enhanced in vitro calcification compared with wildtype cells. By high-throughput screening, three novel compounds, 5361418, 5923412, and 5804079, were identified that inhibit TNALP pyrophosphatase function through an uncompetitive mechanism, with high affinity and specificity when measured at both pH 9.8 and 7.5. These compounds were shown to reduce the calcification by Enpp1,/, VSMCs. Furthermore, using an ex vivo rat whole aorta PPi hydrolysis assay, we showed that pyrophosphatase activity was inhibited by all three lead compounds, with compound 5804079 being the most potent at pH 7.5. Conclusions: We conclude that TNALP is a druggable target for the treatment and/or prevention of ectopic calcification. The lead compounds identified in this study will serve as scaffolds for medicinal chemistry efforts to develop drugs for the treatment of soft tissue calcification. [source] ChemInform Abstract: Imidazoacridin-6-ones as Novel Inhibitors of the Quinone Oxidoreductase NQO2.CHEMINFORM, Issue 42 2010K. A. Nolan Abstract NSC660841 (I) is found to be the most potent inhibitor of NQO2 reported. [source] Trimethylsilylpyrazoles as Novel Inhibitors of p38 MAP Kinase: A New Use of Silicon Bioisosteres in Medicinal Chemistry.CHEMINFORM, Issue 22 2007Matthew J. Barnes Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] The Design and Synthesis of Novel Inhibitors of NADH:Ubiquinone Oxidoreductase.CHEMINFORM, Issue 17 2004Stephen D. Lindell Abstract For Abstract see ChemInform Abstract in Full Text. [source] High Throughput Screening Identifies Novel Inhibitors of Escherichia coli Dihydrofolate Reductase that Are Competitive with Dihydrofolate.CHEMINFORM, Issue 43 2003Michela Zolli-Juran Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cyclohex-1-ene Carboxylic Acids: Synthesis and Biological Evaluation of Novel Inhibitors of Human 5, Reductase.CHEMINFORM, Issue 28 2003Eckhard Baston Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Novel Inhibitors of the Enzyme Estrone Sulfatase (ES).CHEMINFORM, Issue 27 2001Sabbir Ahmed Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Novel Inhibitors of Checkpoint Kinase,1CHEMMEDCHEM, Issue 11 2007Kenneth Inhibition of Chk1 kinase has garnered attention as a possible complement to DNA-damaging chemotherapeutic agents, widening their therapeutic window. As a result, several distinct classes of Chk1 inhibitors have been recently identified with selected compound advancing to clinical trials stage. This review focuses on the challenges and recent progress achieved in this area from a medicinal chemistry perspective. [source] Novel inhibitors targeted to methionine aminopeptidase 2 (MetAP2) strongly inhibit the growth of cancers in xenografted nude modelINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Eunyoung Chun Abstract Inhibition of angiogenesis is emerging as a promising strategy for the treatment of cancer. In our study reported here, the effects of 4 highly potent methionine aminopeptidase 2 (MetAP2) inhibitors, IDR-803, IDR-804, IDR-805 and CKD-732 (designed by structure-based molecular modeling), on angiogenesis and tumor growth were assessed. Concentrations of these inhibitors as low as 2.5 nM were able to inhibit the growth of human umbilical vein endothelial cells (HUVEC) by as much as 50%, arresting growth in the G1 stage of mitosis. An intracellular accumulation of p21WAF1/Cip1 protein was also observed. Furthermore, at higher concentrations (25 nM) of these 4 MetAP2 inhibitors, a significant induction of apoptosis was apparent in the same HUVEC cultures. As a result of these findings, the possible anticancer effects of these inhibitors were examined, utilizing the SNU-398 hepatoma cell line. Interestingly, pretreatment with these inhibitors led to an increased number of apoptotic cells of up to 60% or more, compared to untreated controls. Moreover, utilizing an in vivo xenografted murine model, these inhibitors suppressed the growth of engrafted tumor. In conclusion, these 4 inhibitory compounds potently exert an antiangiogenic effect to inhibit the growth of cancers in vivo and could potentially be useful for the treatment of a variety of cancers. © 2004 Wiley-Liss, Inc. [source] Polypropylene glycol is a selective binding inhibitor for LTA and other structurally related TLR2 agonistsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2008Christian Draing Abstract Polypropylene glycol (PPG) is commonly added to bacterial cultures to avoid foaming. However, lipoteichoic acid (LTA) from bacteria grown with PPG lacked cytokine-inducing potency in human blood. We tested the blocking efficacy of several glycols on the cytokine response to staphylococcal LTA in human blood. PPG 1200 was the most potent inhibitor tested, shown for TNF, IL-1,, IL-6, IL-8, IL-10 and TGF-, induction, and displayed no cytotoxic effects. TNF induction by Staphylococcus aureus or by Toll-like receptor (TLR)2 agonists (di- and triacylated lipopeptides and LTA) was also inhibited by PPG 1200, but not that induced by Escherichia,coli or TLR4 agonists. In flow cytometric studies, PPG-carrying nanobeads bound more rhodamine-labeled LTA than those with glycerol. Additionally, the methyl group peak in the 1H-NMR of LTA shifted after incubation with increasing PPG 1200 concentrations. Sequential incubation of polystyrene plates with LTA, then PPG 1200 and then blood, with washing steps in between, showed that LTA-induced TNF release was inhibited. But when PPG 1200 was pre-incubated with blood that was washed before LTA was added, TNF induction was not repressed, demonstrating that PPG binds LTA and not cellular structures. In summary, PPG 1200 is a novel inhibitor of cytokine induction by TLR2 agonists, which interferes directly with the ligands. [source] ApoG2, a novel inhibitor of antiapoptotic Bcl-2 family proteins, induces apoptosis and suppresses tumor growth in nasopharyngeal carcinoma xenograftsINTERNATIONAL JOURNAL OF CANCER, Issue 10 2008Zhe-Yu Hu Abstract Nasopharyngeal carcinoma (NPC) is a common malignant tumor in South China. It has been reported that overexpression of antiapoptotic Bcl-2 family proteins in NPC has caused the lack of long-term efficacy of conventional therapies. Apogossypolone (ApoG2), a novel small-molecule inhibitor of antiapoptotic Bcl-2 family proteins, has been discovered as the optimized derivative of gossypol. In this study, we found that in NPC cells, ApoG2 totally blocked the antiapoptotic function of Bcl-2 family proteins without affecting the expression levels of these proteins. ApoG2 selectively inhibited proliferation of 3 NPC cell lines (C666-1, CNE-1 and CNE-2) that highly expressed the antiapoptotic Bcl-2 proteins. This inhibitory activity was associated with release of cytochrome c, activation of caspase-9 and caspase-3 and apoptosis of sensitive NPC cells. However, ApoG2 had no obvious inhibitory effect on NPC cell line HONE-1, which expressed antiapoptotic Bcl-2 and Bcl-xL at a low level. We further found that ApoG2 effectively suppressed tumor growth of NPC xenografts in nude mice and enhanced the antitumor effect of CDDP (cisplatin) on NPC cells in vitro and in vivo. Immunohistochemical results showed that the expression of CD31 decreased after ApoG2 treatment, which suggested inhibition of angiogenesis in NPC xenografts. Our findings strongly suggest that ApoG2 may serve as a novel inhibitor of Bcl-2 family proteins and, by targeting these proteins, may become a promising drug for the treatment of NPC. © 2008 Wiley-Liss, Inc. [source] A Vacuolar ATPase Inhibitor, FR167356, Prevents Bone Resorption in Ovariectomized Rats With High Potency and Specificity: Potential for Clinical Application,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2005Kazuaki Niikura MS Abstract FR167356, a novel inhibitor of vacuolar ATPase, has high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. FR167356 is the first compound of this nature to be tested. It has the potential to be useful for clinical application. Introduction: It has been suggested that the key issue regarding the therapeutic usefulness of V-ATPase inhibitors is their selectivity. Materials and Methods: In in vitro and in vivo studies, we compared FR167356 with other vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 and SB242784. H+ transport by various membrane vesicles was assayed by measuring uptake of acridine orange. Inhibitory activity against in vitro bone resorption was examined by measuring the Ca2+ release from cultured calvariae. In vivo, hypercalcemia was induced by retinoic acid in thyroparathyroidectomized-ovariectomized rats, and the effect on serum Ca2+ level was assessed. Ovariectomized rats were treated with FR167356 or SB242784. One week after surgery, free deoxypyridinoline levels in 24-h urine samples, which were collected from 6 h after administration of FR167356, were measured by ELISA. After 4 weeks of treatment, plasma biochemical parameters were analyzed. BMD of the distal femur metaphysis was measured with pQCT. Histomorphometric analysis of the proximal tibias was performed. Blood gases of rats treated with FR167356 were measured with a blood gas analyzer for estimating the effect of FR167356 on in vivo function of renal V-ATPase. Results: FR167356, which is distinctly different from other V-ATPase inhibitors, has a high potency against osteoclast V-ATPase and low potency against lysosomal V-ATPase. Similarly, FR167356 inhibited bone resorption in vitro when stimulated by PTH, IL-1, and IL-6. FR167356 reduced retinoic acid-induced hypercalcemia in thyroparathyroidectomized-ovariectomized rats in a dose-dependent manner. Moreover, FR167356 was shown to restore BMD of ovariectomized rats caused by the inhibition of bone resorption. Ovariectomized rats treated with FR167356 did not show adverse symptoms, whereas SB242784 caused a decrease in body weight gain and significant changes in two plasma biochemical parameters. Interestingly, FR167356 treatment did not affect blood acid-base balance; however, FR167356 inhibited renal V-ATPase with a similar potency as for osteoclast V-ATPase inhibition. Conclusion: Comparison of FR167356 with SB242784 implies that the characteristics of FR167356 may be more appropriate for clinical application as a V-ATPase inhibitor. [source] A novel inhibitor of Smad-dependent transcriptional activation suppresses tissue fibrosis in mouse models of systemic sclerosisARTHRITIS & RHEUMATISM, Issue 11 2009Minoru Hasegawa Objective Tissue fibrosis is a major cause of morbidity and mortality in systemic sclerosis (SSc), and an increasing number of promising molecular targets for antifibrotic therapies have been described recently. Transforming growth factor , (TGF,) is well known to be the principal factor that leads to tissue fibrosis. The present study was undertaken to investigate the ability of HSc025, a novel small compound that antagonizes TGF,/Smad signaling through the activation of nuclear translocation of Y-box binding protein 1, to prevent tissue fibrosis in vitro or in mouse models of SSc. Methods Human dermal fibroblasts were exposed to HSc025 at various concentrations in the presence of TGF,, and levels of collagen or fibronectin expression were determined. HSc025 (15 mg/kg/day for 14 days) was administered orally to tight skin mice and to mice with bleomycin-induced pulmonary fibrosis. Improvement of tissue fibrosis was evaluated by histologic or biochemical examination in each model. Results Pretreatment with HSc025 prevented Smad-dependent promoter activation, in a dose-dependent manner; however, HSc025 had no effect on TGF,-induced phosphorylation of Smad3. The inhibitory effects of HSc025 on TGF,-induced collagen or fibronectin expression were also confirmed in vitro. Orally administered HSc025 significantly reduced hypodermal thickness and hydroxyproline content in tight skin mice, and markedly decreased the histologic score and hydroxyproline content in the lungs of bleomycin-treated mice. Conclusion These results demonstrate that HSc025 is a novel inhibitor of TGF,/Smad signaling, resulting in the improvement of skin and pulmonary fibrosis. Orally available HSc025 might therefore be useful in the treatment of SSc. [source] Polystyrene microbridges used in sitting-drop crystallization release 1,4-diphenyl-2-butene, a novel inhibitor of human MAO BACTA CRYSTALLOGRAPHICA SECTION D, Issue 10 2003Frantisek Hubálek In the course of protein-structure determinations of the membrane-bound enzyme monoamine oxidase B (MAO B) by X-ray crystallography, a compound was found in the active site of the enzyme that consists of two phenyl rings separated by four C atoms. This compound was identified by chromatography and by mass spectrometry to be 1,4-diphenyl-2-butene and found to be a component of the polystyrene microbridges that are used in protein crystallization. This compound is present at a level of ,0.3,mg (,1.5,µmol) per microbridge and functions as a competitive inhibitor of MAO B with a Ki of 35,µM. The presence of detergents in the crystallization solutions facilitates the extraction of this compound from the polymer medium. [source] Pharmacological profile of SL 59.1227, a novel inhibitor of the sodium/hydrogen exchangerBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2000Janine Lorrain The NHE1 isoform of the Na+/H+ exchanger plays an important role in the regulation of intracellular pH and in cardiac cell injury caused by ischaemia and reperfusion. SL 59.1227 is a novel imidazolypiperidine Na+/H+ antiport inhibitor which is structurally unrelated to previously described acylguanidine inhibitors such as cariporide. Recovery of pHi following an intracellular acid load was measured in CCL39-derived PS120 variant cells, selectively expressing either NHE1 or NHE2 isoforms of the Na+/H+ exchanger. pHi recovery was potently and selectively slowed by SL 59.1227 in NHE1-expressing cells (IC50 3.3±1.3 nM) versus NHE2-expressing cells (2.3±1.0 ,M). The respective IC50 values for cariporide were 103±28 nM (NHE1) and 73±46 ,M (NHE2). In anaesthetized rats following left coronary artery occlusion (7 min) and reperfusion (10 min) SL 59.1227 (10,100 ,g kg,1 min,1 i.v.) inhibited ischaemia-mediated ventricular tachycardia (71,100%) and reperfusion-induced ventricular fibrillation (75,87%) and prevented mortality. Bolus i.v. administration of SL 59.1227 (1 mg kg,1) produced anti-arrhythmic effects when administered either before or during ischaemia. Cardiac infarct size was determined in anaesthetized rabbits following left coronary artery occlusion (30 min) and reperfusion (120 min). Infarct size measured as a percentage of the area at risk was 36.2±3.4% (control group) versus 15.3±3.9% (SL 59.1227 0.6 mg kg,1 i.v.). SL 59.1227 is the first example of a potent and NHE1-selective non-acylguanidine Na+/H+ exchanger inhibitor. It possesses marked cardioprotective properties. British Journal of Pharmacology (2000) 131, 1188,1194; doi:10.1038/sj.bjp.0703671 [source] Commercial broth microdilution panel validation and reproducibility trials for NVP PDF-713 (LBM 415), a novel inhibitor of bacterial peptide deformylaseCLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2004T. R. Fritsche Abstract NVP PDF-713 (LBM 415) is a peptide deformylase inhibitor being progressed into clinical trials. Dry-form broth microdilution panels of NVP PDF-713 were compared to reference MIC panels of 552 recent clinical isolates. Most (99.2%) dry-form MIC results were within ± 1 log2 dilution of the reference panel MICs. Of the bacteria tested, Streptococcus pneumoniae and Haemophilus influenzae showed a bias towards higher and lower MICs, respectively. Same-day and between-day reproducibility tests showed that 98.9% and 96.7% of MIC values, respectively, were within ± 1 log2 dilution step, thereby demonstrating a high degree of reliability of the dry-form MIC product for clinical studies. [source] Dynamic Enzymatic Kinetic Resolution of Methyl 2,3-Dihydro-1H -indene-1-carboxylateEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 35 2009Jörg Pietruszka Abstract A new reaction setup for kinetic enzymatic resolution was established and is demonstrated for the case of the hydrolase-catalysed conversion of methyl 2,3-dihydro-1H -indene-1-carboxylate (1) in conjunction with a base-catalysed racemisation. The system allows controlled racemisation, resulting in efficient dynamic kinetic resolution (DKR) of the title compound. Short reaction times and high enantioselectivities were obtained with CAL-B and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene). Compound (R)- 1 (ee 95,%) served as a starting material in a domino reaction that led to the biaryl indanyl ketone (R)- 8, a lead compound for novel inhibitors of peptidyl-prolyl- cis/trans -isomerases, in 94,% ee. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Structural and thermodynamic insights into the binding mode of five novel inhibitors of lumazine synthase from Mycobacterium tuberculosisFEBS JOURNAL, Issue 20 2006Ekaterina Morgunova Recently published genomic investigations of the human pathogen Mycobacterium tuberculosis have revealed that genes coding the proteins involved in riboflavin biosynthesis are essential for the growth of the organism. Because the enzymes involved in cofactor biosynthesis pathways are not present in humans, they appear to be promising candidates for the development of therapeutic drugs. The substituted purinetrione compounds have demonstrated high affinity and specificity to lumazine synthase, which catalyzes the penultimate step of riboflavin biosynthesis in bacteria and plants. The structure of M. tuberculosis lumazine synthase in complex with five different inhibitor compounds is presented, together with studies of the binding reactions by isothermal titration calorimetry. The inhibitors showed the association constants in the micromolar range. The analysis of the structures demonstrated the specific features of the binding of different inhibitors. The comparison of the structures and binding modes of five different inhibitors allows us to propose the ribitylpurinetrione compounds with C4,C5 alkylphosphate chains as most promising leads for further development of therapeutic drugs against M. tuberculosis. [source] Discovery and design of novel inhibitors of botulinus neurotoxin A: targeted ,hinge' peptide librariesJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2003J. Hayden Abstract Intoxication by the zinc protease botulinus neurotoxin A (BoNT-A) results from cleavage of a single Q,R bond in the neuronal protein SNAP-25, which disables the docking mechanism required for neurotransmitter release. In the present study, potential inhibitors of BoNT-A were assessed from their effects on the BoNT-A cleavage of a synthetic 17-mer peptide (SNAP-25, residues 187,203) spanning the Q,R cleavage site. Compounds that inhibited BoNT-A included thiols (zinc chelators) such as dithiothreitol, dimercaptopropanesulfonic acid, mercaptosuccinic acid and captopril. In addition, compounds containing multiple acidic functions, such as the SNARE motif V2 (ELDDRADALQ), the tripeptide Glu-Glu-Glu and the steroid glycoside glycyrrhizic acid, were effective inhibitors. ,Hinge' peptide mini-libraries (PMLs) having the structure acetyl-X1 -X2 -linker-X3 -X4 -NH2 or X1 -X2 -linker-X3, where X1,X4 were mixtures of selected amino acids and the flexible linker was 4-aminobutyric acid, also provided effective inhibition. Targeted PMLs containing the acidic amino acids Asp and Glu, the scissile-bond amino acids Gln and Arg and the zinc chelators His and Cys produced pronounced inhibition of BoNT-A. Deconvolution of these libraries will provide novel ligands with improved inhibitory potency as leads in the design of peptide mimetics to treat BoNT poisoning. Copyright ? 2003 Crown in the right of Canada. Published by John Wiley and Sons, Ltd. [source] Novel Inhibitors of Alkaline Phosphatase Suppress Vascular Smooth Muscle Cell Calcification,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2007Sonoko Narisawa Abstract We report three novel inhibitors of the physiological pyrophosphatase activity of alkaline phosphatase and show that these compounds are capable of reducing calcification in two models of vascular calcification (i.e., they suppress in vitro calcification by cultured Enpp1,/, VSMCs and they inhibit the increased pyrophosphatase activity in a rat aortic model). Introduction: Genetic ablation of tissue-nonspecific alkaline phosphatase (TNALP) leads to accumulation of the calcification inhibitor inorganic pyrophosphate (PPi). TNALP deficiency ameliorates the hypermineralization phenotype in Enpp1,/, and ank/ank mice, two models of osteoarthritis and soft tissue calcification. We surmised that the pharmacological inhibition of TNALP pyrophosphatase activity could be used to prevent/suppress vascular calcification. Materials and Methods: Comprehensive chemical libraries were screened to identify novel drug-like compounds that could inhibit TNALP pyrophosphatase function at physiological pH. We used these novel compounds to block calcification by cultured vascular smooth muscle cells (VSMCs) and to inhibit the upregulated pyrophosphatase activity in a rat aortic calcification model. Results: Using VSMC cultures, we determined that Enpp1,/, and ank/ank VSMCs express higher TNALP levels and enhanced in vitro calcification compared with wildtype cells. By high-throughput screening, three novel compounds, 5361418, 5923412, and 5804079, were identified that inhibit TNALP pyrophosphatase function through an uncompetitive mechanism, with high affinity and specificity when measured at both pH 9.8 and 7.5. These compounds were shown to reduce the calcification by Enpp1,/, VSMCs. Furthermore, using an ex vivo rat whole aorta PPi hydrolysis assay, we showed that pyrophosphatase activity was inhibited by all three lead compounds, with compound 5804079 being the most potent at pH 7.5. Conclusions: We conclude that TNALP is a druggable target for the treatment and/or prevention of ectopic calcification. The lead compounds identified in this study will serve as scaffolds for medicinal chemistry efforts to develop drugs for the treatment of soft tissue calcification. [source] Interactions between neural membrane glycerophospholipid and sphingolipid mediators: A recipe for neural cell survival or suicideJOURNAL OF NEUROSCIENCE RESEARCH, Issue 9 2007Akhlaq A. Farooqui Abstract The neural membranes contain phospholipids, sphingolipids, cholesterol, and proteins. Glycerophospholipids and sphingolipids are precursors for lipid mediators involved in signal transduction processes. Degradation of glycerophospholipids by phospholipase A2 (PLA2) generates arachidonic acid (AA) and docosahexaenoic acids (DHA). Arachidonic acid is metabolized to eicosanoids and DHA is metabolized to docosanoids. The catabolism of glycosphingolipids generates ceramide, ceramide 1-phosphate, sphingosine, and sphingosine 1-phosphate. These metabolites modulate PLA2 activity. Arachidonic acid, a product derived from glycerophospholipid catabolism by PLA2, modulates sphingomyelinase (SMase), the enzyme that generates ceramide and phosphocholine. Furthermore, sphingosine 1-phosphate modulates cyclooxygenase, an enzyme responsible for eicosanoid production in brain. This suggests that an interplay and cross talk occurs between lipid mediators of glycerophospholipid and glycosphingolipid metabolism in brain tissue. This interplay between metabolites of glycerophospholipid and sphingolipid metabolism may play an important role in initiation and maintenance of oxidative stress associated with neurologic disorders as well as in neural cell proliferation, differentiation, and apoptosis. Recent studies indicate that PLA2 and SMase inhibitors can be used as neuroprotective and anti-apoptotic agents. Development of novel inhibitors of PLA2 and SMase may be useful for the treatment of oxidative stress, and apoptosis associated with neurologic disorders such as stroke, Alzheimer disease, Parkinson disease, and head and spinal cord injuries. © 2007 Wiley-Liss, Inc. [source] Glycosylphosphatidylinositols are potential targets for the development of novel inhibitors for aerolysin-type of pore-forming bacterial toxinsMEDICINAL RESEARCH REVIEWS, Issue 2 2010Qiuye Wu Abstract Many bacteria produce toxins that cause damage through the formation of pores in the host cell membrane. Some of these toxins, such as aerolysin, use glycosylphosphatidylinositols (GPIs) as their binding receptors to assist the pore formation on the host cell surface and the subsequent insertion of the resultant pores into the cell membrane. GPIs are a class of complex glycolipids that anchor surface proteins and glycoproteins onto the cell membrane in eukaryotic species. This review has summarized the reported evidences supporting the GPI-dependent pore-forming mechanism for aerolysin-type of toxins and analyzed the possibility of targeting this unique process for the design and development of novel GPI-based inhibitors for these pore-forming bacterial toxins. © 2009 Wiley Periodicals, Inc. Med Res Rev, 30, No. 2, 258,269, 2010 [source] HIV-1 integrase inhibitors: 2005,2006 updateMEDICINAL RESEARCH REVIEWS, Issue 1 2008Raveendra Dayam Abstract HIV-1 integrase (IN) catalyzes the integration of proviral DNA into the host genome, an essential step for viral replication. Inhibition of IN catalytic activity provides an attractive strategy for antiretroviral drug design. Currently two IN inhibitors, MK-0518 and GS-9137, are in advanced stages of human clinical trials. The IN inhibitors in clinical evaluation demonstrate excellent antiretroviral efficacy alone or in combination regimens as compared to previously used clinical antiretroviral agents in naive and treatment-experienced HIV-1 infected patients. However, the emergence of viral strains resistant to clinically studied IN inhibitors and the dynamic nature of the HIV-1 genome demand a continued effort toward the discovery of novel inhibitors to keep a therapeutic advantage over the virus. Continued efforts in the field have resulted in the discovery of compounds from diverse chemical classes. In this review, we provide a comprehensive report of all IN inhibitors discovered in the years 2005 and 2006. © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 1, 118,154, 2008 [source] Structure and function of the Mur enzymes: development of novel inhibitorsMOLECULAR MICROBIOLOGY, Issue 1 2003Ahmed El Zoeiby Summary One of the biggest challenges for recent medical research is the continuous development of new antibiotics interacting with bacterial essential mechanisms. The machinery for peptidoglycan biosynthesis is a rich source of crucial targets for antibacterial chemotherapy. The cytoplasmic steps of the biosynthesis of peptidoglycan precursor, catalysed by a series of Mur enzymes, are excellent candidates for drug development. There has been growing interest in these bacterial enzymes over the last decade. Many studies attempted to understand the detailed mechanisms and structural features of the key enzymes MurA to MurF. Only MurA is inhibited by a known antibiotic, fosfomycin. Several attempts made to develop novel inhibitors of this pathway are discussed in this review. Three novel inhibitors of MurA were identified recently. 4-Thiazolidinone compounds were designed as MurB inhibitors. Many phosphinic acid derivatives and substrate analogues were identified as inhibitors of the MurC to MurF amino acid ligases. [source] High-quality crystals of human haematopoietic prostaglandin D synthase with novel inhibitorsACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Sachiko Takahashi Human haematopoietic prostaglandin D synthase (H-PGDS; EC 5.3.99.2) produces prostaglandin D2, an allergic and inflammatory mediator, in mast cells and Th2 cells. H-PGDS has been crystallized with novel inhibitors with half-maximal inhibitory concentrations (IC50) in the low nanomolar range by the counter-diffusion method onboard the Russian Service Module on the International Space Station. The X-ray diffraction of a microgravity-grown crystal of H-PGDS complexed with an inhibitor with an IC50 value of 50,nM extended to 1.1,Å resolution at 100,K using SPring-8 synchrotron radiation, which is one of the highest resolutions obtained to date for this protein. [source] Crystallization and preliminary crystallographic studies of dihydrofolate reductase-thymidylate synthase from Trypanosoma cruzi, the Chagas disease pathogenACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009Penchit Chitnumsub Trypanosoma cruzi dihydrofolate reductase-thymidylate synthase (TcDHFR-TS) was crystallized in complexes with the dihydrotriazine-based or quinazoline-based antifolates C-448, cycloguanil (CYC) and Q-8 in order to gain insight into the interactions of this DHFR enzyme with classical and novel inhibitors. The TcDHFR-TS,C-448,NDP,dUMP crystal belonged to space group C2221 with two molecules per asymmetric unit and diffracted to 2.37,Å resolution. The TcDHFR-TS,CYC, TcDHFR-TS,CYC,NDP and TcDHFR-TS,Q-8,NDP crystals belonged to space group P21 with four molecules per asymmetric unit and diffracted to 2.1, 2.6 and 2.8,Å resolution, respectively. Crystals belonging to the two different space groups were suitable for structure determination. [source] Structure of Staphylococcus aureus guanylate monophosphate kinaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2006Kamel El Omari Nucleotide monophosphate kinases (NMPKs) are potential antimicrobial drug targets owing to their role in supplying DNA and RNA precursors. The present work reports the crystal structure of Staphylococcus aureus guanylate monophosphate kinase (SaGMK) at 1.9,Å resolution. The structure shows that unlike most GMKs SaGMK is dimeric, confirming the role of the extended C-terminus in dimer formation as first observed for Escherichia coli GMK (EcGMK). One of the two SaGMK dimers within the crystal asymmetric unit has two monomers in different conformations: an open form with a bound sulfate ion (mimicking the ,-phosphate of ATP) and a closed form with bound GMP and sulfate ion. GMP-induced domain movements in SaGMK can thus be defined by comparison of these conformational states. Like other GMKs, the binding of GMP firstly triggers a partial closure of the enzyme, diminishing the distance between the GMP-binding and ATP-binding sites. In addition, the closed structure shows the presence of a potassium ion in contact with the guanine ring of GMP. The potassium ion appears to form an integral part of the GMP-binding site, as the Tyr36 side chain has significantly moved to form a metal ion,ligand coordination involving the lone pair of the side-chain O atom. The potassium-binding site might also be exploited in the design of novel inhibitors. [source] Structure of Staphylococcus aureus cytidine monophosphate kinase in complex with cytidine 5,-monophosphateACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 8 2006Jingshan Ren The crystal structure of Staphylococcus aureus cytidine monophosphate kinase (CMK) in complex with cytidine 5,-monophosphate (CMP) has been determined at 2.3,Å resolution. The active site reveals novel features when compared with two orthologues of known structure. Compared with the Streptococcus pneumoniae CMK solution structure of the enzyme alone, S. aureus CMK adopts a more closed conformation, with the NMP-binding domain rotating by ,16° towards the central pocket of the molecule, thereby assembling the active site. Comparing Escherichia coli and S. aureus CMK,CMP complex structures reveals differences within the active site, including a previously unreported indirect interaction of CMP with Asp33, the replacement of a serine residue involved in the binding of CDP by Ala12 in S. aureus CMK and an additional sulfate ion in the E. coli CMK active site. The detailed understanding of the stereochemistry of CMP binding to CMK will assist in the design of novel inhibitors of the enzyme. Inhibitors are required to treat the widespread hospital infection methicillin-resistant S. aureus (MRSA), currently a major public health concern. [source] | |||||||||||||||||||||||||||||||