Discovery of a celecoxib binding site on PTGES with a cleavable chelation-assisted biotin probe

2019 ◽  
Author(s):  
David K. Miyamoto ◽  
Hope A. Flaxman ◽  
Hung-Yi Wu ◽  
Jinxu Gao ◽  
Christina M. Woo

AbstractThe coxibs are a subset of non-steroidal anti-inflammatory drugs (NSAIDs) that primarily target cyclooxygenase-2 (COX-2) to inhibit prostaglandin signaling and reduce inflammation. However, mechanisms to inhibit other members of the prostaglandin signaling pathway may improve selectivity and reduce off-target toxicity. Here, we report a novel binding site for celecoxib on prostaglandin E synthase (PTGES), an enzyme downstream of COX-2 in the prostaglandin signaling pathway, using a cleavable chelation-assisted biotin probe 6. Evaluation of the multi-functional probe 6 revealed significantly improved tagging efficiencies attributable to the embedded picolyl functional group. Application of the probe 6 within the small molecule interactome mapping by photo-affinity labeling (SIM-PAL) platform using photo-celecoxib as a reporter for celecoxib identified PTGES and other membrane proteins in the top eight enriched proteins from A549 cells. Carbonic anhydrase 12, a known protein target of celecoxib, was also enriched. Four binding sites to photo-celecoxib were additionally mapped by the probe 6, including a binding site with PTGES. The binding interaction with PTGES was validated by competitive displacement with celecoxib and known PTGES inhibitor licofelone. The binding site of photo-celecoxib on PTGES enabled the development of a structural model of the interaction and will inform the design of new selective inhibitors of the prostaglandin signaling pathway.

2007 ◽  
Vol 282 (38) ◽  
pp. 27622-27632 ◽  
Author(s):  
Byeong-Churl Jang ◽  
Su-Haeng Sung ◽  
Jong-Gu Park ◽  
Jong-Wook Park ◽  
Jae Hoon Bae ◽  
...  

COX-2 and its products, including prostaglandin E2, are involved in many inflammatory processes. Glucosamine (GS) is an amino monosaccharide and has been widely used for alternative regimen of (osteo) arthritis. However, the mechanism of action of GS on COX-2 expression remains unclear. Here we describe a new action mechanism of glucosamine hydrochloride (GS-HCl) to tackle endogenous and agonistdriven COX-2 at protein level. GS-HCl (but not GS sulfate, N-acetyl GS, or galactosamine HCl) resulted in a shift in the molecular mass of COX-2 from 72–74 to 66–70 kDa and concomitant inhibition of prostaglandin E2 production in a concentration-dependent manner in interleukin (IL)-1β-treated A549 human lung epithelial cells. Remarkably, GS-HCl-mediated decrease in COX-2 molecular mass was associated with inhibition of COX-2 N-glycosylation during translation, as assessed by the effect of tunicamycin, the protein N-glycosylation inhibitor, or of cycloheximide, the translation inhibitor, on COX-2 modification. Specifically, the effect of low concentration of GS-HCl (1 mm) or of tunicamycin (0.1 μg/ml) to produce the aglycosylated COX-2 was rescued by the proteasomal inhibitor MG132 but not by the lysosomal or caspase inhibitors. However, the proteasomal inhibitors did not show an effect at 5 mm GS-HCl, which produced the aglycosylated or completely deglycosylated form of COX-2. Notably, GS-HCl (5 mm) also facilitated degradation of the higher molecular species of COX-2 in IL-1β-treated A549 cells that was retarded by MG132. GS-HCl (5 mm) was also able to decrease the molecular mass of endogenous and IL-1β- or tumor necrosis factor-α-driven COX-2 in different human cell lines, including Hep2 (bronchial) and H292 (laryngeal). However, GS-HCl did not affect COX-1 protein expression. These results demonstrate for the first time that GS-HCl inhibits COX-2 activity by preventing COX-2 co-translational N-glycosylation and by facilitating COX-2 protein turnover during translation in a proteasome-dependent manner.


2002 ◽  
Vol 283 (3) ◽  
pp. L612-L618 ◽  
Author(s):  
Helen C. Rodgers ◽  
Linhua Pang ◽  
Elaine Holland ◽  
Lisa Corbett ◽  
Simon Range ◽  
...  

Interleukin (IL)-8, the C-X-C chemokine, is a potent neutrophil chemoattractant that has been implicated in a number of inflammatory airway diseases such as cystic fibrosis. Here we tested the hypothesis that bradykinin, an inflammatory mediator and chloride secretagogue, would increase IL-8 generation in airway epithelial cells through autocrine generation of endogenous prostanoids. Bradykinin increased IL-8 generation in both a non-cystic fibrosis (A549) and cystic fibrosis epithelial cell line (CFTE29[Formula: see text]) that was inhibited by the nonselective cyclooxygenase (COX) inhibitor indomethacin and the COX-2 selective inhibitor NS-398. COX-2 was the only isoform of COX expressed in both cell lines. Furthermore, the COX substrate arachidonic acid and exogenous prostaglandin E2 both increased IL-8 release in A549 cells. These results suggest that bradykinin may contribute to neutrophilic inflammation in the airway by generation of IL-8 from airway epithelial cells. The dependence of this response on endogenous production of prostanoids by COX-2 suggests that selective COX-2 inhibitors may have a role in the treatment of airway diseases characterized by neutrophilic inflammation such as cystic fibrosis or chronic obstructive pulmonary disease.


2001 ◽  
Vol 69 (8) ◽  
pp. 5056-5063 ◽  
Author(s):  
Tae Il Kim ◽  
Yong Chan Lee ◽  
Kwang Hyoung Lee ◽  
Jae Ho Han ◽  
Chae Yoon Chon ◽  
...  

ABSTRACT Helicobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) are two well-known important causative factors of gastric damage. While H. pylori increases apoptosis and the proliferation of gastric epithelial cells and is an important factor in peptic ulcer and gastric cancer, NSAIDs induce cell apoptosis and have antineoplastic effects. We investigated the effects of NSAIDs (a nonselective cyclooxygenase [COX] inhibitor [indomethacin] and a selective COX-2 inhibitor [NS-398]) on the apoptosis and proliferation of gastric epithelial cells and gastric inflammation inH. pylori-infected mice. C57BL/6 mice were sacrificed 8 weeks after H. pylori SS1 inoculation. Indomethacin (2 mg/kg) or NS-398 (10 mg/kg) was administered subcutaneously once daily for 10 days before sacrifice. The following were assessed: gastric inflammatory activity, gastric COX protein expression by Western blotting; gastric prostaglandin E2 levels by enzyme immunoassay, apoptosis by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, and cell proliferation by Ki67 immunostaining. Compared to the controls, H. pylori infection and/or NSAID treatment increased COX-1 and COX-2 protein expression. Gastric prostaglandin E2 levels, apoptotic index, cell proliferation index, neutrophil activity, and the degree of chronic inflammation were all increased by H. pylori infection, and these effects were significantly decreased by indomethacin treatment. However, NS-398 treatment after H. pylori infection did not induce a significant reduction, although it did result in a tendency to decrease. These results show that NSAIDs can reverse the increased apoptosis and proliferation of epithelial cells and inflammatory activity in the stomachs of H. pylori-infected mice and that, like COX-2 activation, COX-1 induction contributes to the change of gastric mucosal cell turnover and inflammation induced by H. pylori infection.


2012 ◽  
Vol 303 (5) ◽  
pp. L401-L412 ◽  
Author(s):  
Chih-Chung Lin ◽  
I-Ta Lee ◽  
Wan-Ling Wu ◽  
Wei-Ning Lin ◽  
Chuen-Mao Yang

Non-small cell lung carcinoma (NSCLC) accounts for most of all lung cancers, which is the leading cause of mortality in human beings. High level of cyclooxygenase-2 (COX-2) is one of the features of NSCLC and related to the low survival rate of NSCLC. However, whether extracellular nucleotides releasing from stressed resident tissues contributes to the expression of COX-2 remains unclear. Here, we showed that stimulation of A549 cells by adenosine 5′- O-(3-thiotriphosphate) (ATPγS) led to an increase in COX-2 gene expression and prostaglandin E2 (PGE2) synthesis, revealed by Western blotting, RT-PCR, promoter assay, and enzyme-linked immunosorbent assay. In addition, ATPγS induced intracellular reactive oxygen species (ROS) generation through the activation of NADPH oxidase. The increase of ROS level resulted in activation of the c-Src/epidermal growth factor receptor (EGFR)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor (NF)-κB cascade. We also found that activated Akt was translocated into the nucleus and recruited with NF-κB and p300 to form a complex. Thus, activation of p300 modulated the acetylation of histone H4 via the NADPH oxidase/c-Src/EGFR/PI3K/Akt/NF-κB cascade stimulated by ATPγS. Our results are the first to show a novel role of NADPH oxidase-dependent Akt/p65/p300 complex formation that plays a key role in regulating COX-2/PGE2 expression in ATPγS-treated A549 cells. Taken together, we demonstrated that ATPγS stimulated activation of NADPH oxidase, resulting in generation of ROS, which then activated the downstream c-Src/EGFR/PI3K/Akt/NF-κB/p300 cascade to regulate the expression of COX-2 and synthesis of PGE2 in A549 cells. Understanding the regulation of COX-2 expression and PGE2 release by ATPγS on A549 cells may provide potential therapeutic targets of NSCLC.


mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Molly C. Sutherland ◽  
Nathan L. Tran ◽  
Dustin E. Tillman ◽  
Joshua M. Jarodsky ◽  
Jason Yuan ◽  
...  

ABSTRACTAlthough intracellular heme trafficking must occur for heme protein assembly, only a few heme transporters have been unequivocally discovered and nothing is known about their structure or mechanisms. Cytochromecbiogenesis in prokaryotes requires the transport of heme from inside to outside for stereospecific attachment to cytochromecvia two thioether bonds (at CXXCH). The CcsBA integral membrane protein was shown to transport and attach heme (and thus is a cytochromecsynthetase), but the structure and mechanisms underlying these two activities are poorly understood. We employed a new cysteine/heme crosslinking tool that traps endogenous heme in heme binding sites. We combined these data with a comprehensive imidazole correction approach (for heme ligand interrogation) to map heme binding sites. Results illuminate the process of heme transfer through the membrane to an external binding site (called the WWD domain). Using meta-genomic data (GREMLIN) and Rosetta modeling programs, a structural model of the transmembrane (TM) regions in CcsBA were determined. The heme mapping data were then incorporated to model the TM heme binding site (with TM-His1 and TM-His2 as ligands) and the external heme binding WWD domain (with P-His1 and P-His2 as ligands). Other periplasmic structure/function studies facilitated modeling of the full CcsBA protein as a framework for understanding the mechanisms. Mechanisms are proposed for heme transport from TM-His to WWD/P-His and subsequent stereospecific attachment of heme. A ligand exchange of the P-His1 for histidine of CXXCH at the synthetase active site is suggested.IMPORTANCEThe movement or trafficking of heme is critical for cellular functions (e.g., oxygen transport and energy production); however, intracellular heme is tightly regulated due to its inherent cytotoxicity. These factors, combined with the transient nature of transport, have resulted in a lack of direct knowledge on the mechanisms of heme binding and trafficking. Here, we used the cytochromecbiogenesis system II pathway as a model to study heme trafficking. System II is composed of two integral membrane proteins (CcsBA) which function to transport heme across the membrane and stereospecifically position it for covalent attachment to apocytochromec. We mapped two heme binding domains in CcsBA and suggest a path for heme trafficking. These data, in combination with metagenomic coevolution data, are used to determine a structural model of CcsBA, leading to increased understanding of the mechanisms for heme transport and the cytochromecsynthetase function of CcsBA.


2004 ◽  
Vol 72 (12) ◽  
pp. 6860-6869 ◽  
Author(s):  
Kei-ichi Uchiya ◽  
Toshiaki Nikai

ABSTRACT Salmonella pathogenicity island 2 (SPI-2) is required for intramacrophage survival and systemic infection in mice. We have recently reported that Salmonella enterica causes activation of the protein kinase A (PKA) signaling pathway in a manner dependent on SPI-2, resulting in the upregulation of interleukin-10 expression in macrophages (K. Uchiya et al., Infect. Immun. 72:1964-1973, 2004). We show in the present study the involvement of SPI-2 in a signal transduction pathway that induces the expression of cyclooxygenase 2 (COX-2), an inducible enzyme involved in the synthesis of prostanoids. High levels of prostaglandin E2 (PGE2) and prostacyclin (PGI2), which are known to activate the PKA signaling pathway via their receptors, were induced in J774 macrophages infected with wild-type Salmonella compared to a strain carrying a mutation in the spiC gene, located within SPI-2. The increased production of both prostanoids was dependent on COX-2. COX-2 expression was dose dependently blocked by treatment with a specific inhibitor of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway, and the phosphorylation level of ERK1/2 was higher in macrophages infected with wild-type Salmonella compared to the spiC mutant. Taken together, these results indicate that Salmonella causes an SPI-2-dependent ERK1/2 activation that leads to increased COX-2 expression, resulting in the upregulation of PGE2 and PGI2 production in macrophages. A COX-2 inhibitor inhibited not only Salmonella-induced activation of the PKA signaling pathway but also growth of wild-type Salmonella within macrophages, suggesting that Salmonella utilizes the COX-2 pathway to survive within macrophages and that the mechanism involves activation of the PKA signaling pathway.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 586
Author(s):  
Hyun Ji Eo ◽  
Jun Hyuk Jang ◽  
Gwang Hun Park

Berchemia floribunda (Wall.) Brongn. (BF), which belongs to Rhamnaceae, is a special plant of Anmyeon Island in Korea. BF has been reported to have antioxidant and whitening effects. However, the anti-inflammatory activity of BR has not been elucidated. In this study, we evaluated the anti-inflammatory effect of leaves (BR-L), branches (BR-B) and fruit (BR-F) extracted with 70% ethanol of BR and elucidated the potential signaling pathway in LPS-induced RAW264.7 cells. BR-L showed a strong anti-inflammatory activity through the inhibition of NO production. BR-L significantly suppressed the production of the pro-inflammatory mediators such as iNOS, COX-2, IL-1β, IL-6 and TNF-α in LPS-stimulated RAW264.7 cells. BR-L suppressed the degradation and phosphorylation of IκB-α, which contributed to the inhibition of p65 nuclear accumulation and NF-κB activation. BR-L obstructed the phosphorylation of MAPKs (ERK1/2, p38 and JNK) in LPS-stimulated RAW264.7 cells. Consequently, these results suggest that BR-L may have great potential for the development of anti-inflammatory drugs to treat acute and chronic inflammatory disorders.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7818 ◽  
Author(s):  
Hua Yang ◽  
Yan-Lin Liu ◽  
Yuan-Yuan Tao ◽  
Wei Yang ◽  
Chun-Ping Yang ◽  
...  

The bamboo snout beetle Cyrtotrachelus buqueti is a widely distributed wood-boring pest found in China, and its larvae cause significant economic losses because this beetle targets a wide range of host plants. A potential pest management measure of this beetle involves regulating olfactory chemoreceptors. In the process of olfactory recognition, pheromone-binding proteins (PBPs) play an important role. Homology modeling and molecular docking were conducted in this study for the interaction between CbuqPBP1 and dibutyl phthalate to better understand the relationship between PBP structures and their ligands. Site-directed mutagenesis and binding experiments were combined to identify the binding sites of CbuqPBP1 and to explore its ligand-binding mechanism. The 3D structural model of CbuqPBP1 has six a-helices. Five of these a-helices adopt an antiparallel arrangement to form an internal ligand-binding pocket. When docking dibutyl phthalate within the active site of CbuqPBP1, a CH-π interaction between the benzene ring of dibutyl phthalate and Phe69 was observed, and a weak hydrogen bond formed between the ester carbonyl oxygen and His53. Thus, Phe69 and His53 are predicted to be important residues of CbuqPBP1 involved in ligand recognition. Site-directed mutagenesis and fluorescence assays with a His53Ala CbuqPBP1 mutant showed no affinity toward ligands. Mutation of Phe69 only affected binding of CbuqPBP1 to cedar camphor. Thus, His53 (Between α2 and α3) of CbuqPBP1 appears to be a key binding site residue, and Phe69 (Located at α3) is a very important binding site for particular ligand interactions.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Guangrui Yang ◽  
Lihong Chen

Nonsteroidal anti-inflammatory drugs (NSAIDs), especially cyclooxygenase-2 (COX-2) selective inhibitors, are among the most widely used drugs to treat pain and inflammation. However, clinical trials have revealed that these inhibitors predisposed patients to a significantly increased cardiovascular risk, consisting of thrombosis, hypertension, myocardial infarction, heart failure, and sudden cardiac death. Thus, microsomal prostaglandin E (PGE) synthase-1 (mPGES-1), the key terminal enzyme involved in the synthesis of inflammatory prostaglandin E2(PGE2), and the four PGE2receptors (EP1–4) have gained much attention as alternative targets for the development of novel analgesics. The cardiovascular consequences of targeting mPGES-1 and the PGE2receptors are substantially studied. Inhibition of mPGES-1 has displayed a relatively innocuous or preferable cardiovascular profile. The modulation of the four EP receptors in cardiovascular system is diversely reported as well. In this review, we highlight the most recent advances from our and other studies on the regulation of PGE2, particularly mPGES-1 and the four PGE2receptors, in cardiovascular function, with a particular emphasis on blood pressure regulation, atherosclerosis, thrombosis, and myocardial infarction. This might lead to new avenues to improve cardiovascular disease management strategies and to seek optimized anti-inflammatory therapeutic options.


2019 ◽  
Vol 116 (12) ◽  
pp. 1972-1980 ◽  
Author(s):  
Nicholas S Kirkby ◽  
Joan Raouf ◽  
Blerina Ahmetaj-Shala ◽  
Bin Liu ◽  
Sarah I Mazi ◽  
...  

Abstract Aims Cardiovascular side effects caused by non-steroidal anti-inflammatory drugs (NSAIDs), which all inhibit cyclooxygenase (COX)-2, have prevented development of new drugs that target prostaglandins to treat inflammation and cancer. Microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors have efficacy in the NSAID arena but their cardiovascular safety is not known. Our previous work identified asymmetric dimethylarginine (ADMA), an inhibitor of endothelial nitric oxide synthase, as a potential biomarker of cardiovascular toxicity associated with blockade of COX-2. Here, we have used pharmacological tools and genetically modified mice to delineate mPGES-1 and COX-2 in the regulation of ADMA. Methods and results Inhibition of COX-2 but not mPGES-1 deletion resulted in increased plasma ADMA levels. mPGES-1 deletion but not COX-2 inhibition resulted in increased plasma prostacyclin levels. These differences were explained by distinct compartmentalization of COX-2 and mPGES-1 in the kidney. Data from prostanoid synthase/receptor knockout mice showed that the COX-2/ADMA axis is controlled by prostacyclin receptors (IP and PPARβ/δ) and the inhibitory PGE2 receptor EP4, but not other PGE2 receptors. Conclusion These data demonstrate that inhibition of mPGES-1 spares the renal COX-2/ADMA pathway and define mechanistically how COX-2 regulates ADMA.


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