NK Cells Stimulate Recruitment of cDC1 into the Tumor Microenvironment Promoting Cancer Immune Control

Conventional type 1 dendritic cells (cDC1) are critical for antitumor immunity, and their abundance within tumors is associated with immune-mediated rejection and the success of immunotherapy. Here, we show that cDC1 accumulation in mouse tumors often depends on natural killer (NK) cells that produce the cDC1 chemoattractants CCL5 and XCL1. Similarly, in human cancers, intratumoral CCL5, XCL1, and XCL2 transcripts closely correlate with gene signatures of both NK cells and cDC1 and are associated with increased overall patient survival. Notably, tumor production of prostaglandin E2 (PGE2) leads to evasion of the NK cell-cDC1 axis in part by impairing NK cell viability and chemokine production, as well as by causing downregulation of chemokine receptor expression in cDC1. Our findings reveal a cellular and molecular checkpoint for intratumoral cDC1 recruitment that is targeted by tumor-derived PGE2 for immune evasion and that could be exploited for cancer therapy.

Impaired balance of mitochondrial fission and fusion in Alzheimer's disease

Mitochondrial dysfunction is a prominent feature of Alzheimer's disease (AD) neurons. In this study, we explored the involvement of an abnormal mitochondrial dynamics by investigating the changes in the expression of mitochondrial fission and fusion proteins in AD brain and the potential cause and consequence of these changes in neuronal cells. We found that mitochondria were redistributed away from axons in the pyramidal neurons of AD brain. Immunoblot analysis revealed that levels of DLP1 (also referred to as Drp1), OPA1, Mfn1, and Mfn2 were significantly reduced whereas levels of Fis1 were significantly increased in AD. Despite their differential effects on mitochondrial morphology, manipulations of these mitochondrial fission and fusion proteins in neuronal cells to mimic their expressional changes in AD caused a similar abnormal mitochondrial distribution pattern, such that mitochondrial density was reduced in the cell periphery of M17 cells or neuronal process of primary neurons and correlated with reduced spine density in the neurite. Interestingly, oligomeric amyloid-beta-derived diffusible ligands (ADDLs) caused mitochondrial fragmentation and reduced mitochondrial density in neuronal processes. More importantly, ADDL-induced synaptic change (i.e., loss of dendritic spine and postsynaptic density protein 95 puncta) correlated with abnormal mitochondrial distribution. DLP1 overexpression, likely through repopulation of neuronal processes with mitochondria, prevented ADDL-induced synaptic loss, suggesting that abnormal mitochondrial dynamics plays an important role in ADDL-induced synaptic abnormalities. Based on these findings, we suggest that an altered balance in mitochondrial fission and fusion is likely an important mechanism leading to mitochondrial and neuronal dysfunction in AD brain.

Astrocyte-mediated control of cerebral blood flow

Local increase in blood flow during neural activity forms the basis for functional brain imaging, but its mechanism remains poorly defined. Here we show that cortical astrocytes in vivo possess a powerful mechanism for rapid vasodilation. We imaged the activity of astrocytes labeled with the calcium (Ca(2+))-sensitive indicator rhod-2 in somatosensory cortex of adult mice. Photolysis of caged Ca(2+) in astrocytic endfeet ensheathing the vessel wall was associated with an 18% increase in arterial cross-section area that corresponded to a 37% increase in blood flow. Vasodilation occurred with a latency of only 1-2 s, and both indomethacin and the cyclooxygenase-1 inhibitor SC-560 blocked the photolysis-induced hyperemia. These observations implicate astrocytes in the control of local microcirculation and suggest that one of their physiological roles is to mediate vasodilation in response to increased neural activity.

Impaired mitochondrial dynamics and abnormal interaction of amyloid beta with mitochondrial protein Drp1 in neurons from patients with Alzheimer's disease: implications for neuronal damage

The purpose of our study was to better understand the relationship between mitochondrial structural proteins, particularly dynamin-related protein 1 (Drp1) and amyloid beta (Aβ) in the progression of Alzheimer's disease (AD). Using qRT-PCR and immunoblotting analyses, we measured mRNA and protein levels of mitochondrial structural genes in the frontal cortex of patients with early, definite and severe AD and in control subjects. We also characterized monomeric and oligomeric forms of Aβ in these patients. Using immunoprecipitation/immunoblotting analysis, we investigated the interaction between Aβ and Drp1. Using immunofluorescence analysis, we determined the localization of Drp1 and intraneuronal and oligomeric Aβ in the AD brains and primary hippocampal neurons from Aβ precursor protein (AβPP) transgenic mice. We found increased expression of the mitochondrial fission genes Drp1 and Fis1 (fission 1) and decreased expression of the mitochondrial fusion genes Mfn1 (mitofusin 1), Mfn2 (mitofusin 2), Opa1 (optic atrophy 1) and Tomm40. The matrix gene CypD was up-regulated in AD patients. Results from our qRT-PCR and immunoblotting analyses suggest that abnormal mitochondrial dynamics increase as AD progresses. Immunofluorescence analysis of the Drp1 antibody and the Aβ antibodies 6E10 and A11 revealed the colocalization of Drp1 and Aβ. Drp1 immunoprecipitation/immunoblotting analysis of Aβ antibodies 6E10 and A11 revealed that Drp1 interacts with Aβ monomers and oligomers in AD patients, and these abnormal interactions are increased with disease progression. Primary neurons that were found with accumulated oligomeric Aβ had lost branches and were degenerated, indicating that oligomeric Aβ may cause neuronal degeneration. These findings suggest that in patients with AD, increased production of Aβ and the interaction of Aβ with Drp1 are crucial factors in mitochondrial fragmentation, abnormal mitochondrial dynamics and synaptic damage. Inhibiting, these abnormal interactions may be a therapeutic strategy to reduce mitochondrial fragmentation, neuronal and synaptic damage and cognitive decline in patients with AD.

A comparison of six major platelet function tests to determine the prevalence of aspirin resistance in patients with stable coronary artery disease

AIMS

We sought to compare the results obtained from six major platelet function tests in the assessment of the prevalence of aspirin resistance in patients with stable coronary artery disease.

METHODS AND RESULTS

201 patients with stable coronary artery disease receiving daily aspirin therapy (> or =80 mg) were recruited. Platelet aggregation was measured by: (i) light transmission aggregometry (LTA) after stimulation with 1.6 mM of arachidonic acid (AA), (ii) LTA after adenosine diphosphate (ADP) (5, 10, and 20 microM) stimulation, (iii) whole blood aggregometry, (iv) PFA-100, (v) VerifyNow Aspirin; urinary 11-dehydro-thromboxane B(2) concentrations were also measured. Eight patients (4%, 95% CI 0.01-0.07) were deemed resistant to aspirin by LTA and AA. The prevalence of aspirin resistance varied according to the assay used: 10.3-51.7% for LTA using ADP as the agonist, 18.0% for whole blood aggregometry, 59.5% for PFA-100, 6.7% for VerifyNow Aspirin, and finally, 22.9% by measuring urinary 11-dehydro-thromboxane B(2) concentrations. Results from these tests showed poor correlation and agreement between themselves.

CONCLUSION

Platelet function tests are not equally effective in measuring aspirin's antiplatelet effect and correlate poorly amongst themselves. The clinical usefulness of the different assays to classify correctly patients as aspirin resistant remains undetermined.

The modern pharmacology of paracetamol: therapeutic actions, mechanism of action, metabolism, toxicity and recent pharmacological findings

Paracetamol is used worldwide for its analgesic and antipyretic actions. It has a spectrum of action similar to that of NSAIDs and resembles particularly the COX-2 selective inhibitors. Paracetamol is, on average, a weaker analgesic than NSAIDs or COX-2 selective inhibitors but is often preferred because of its better tolerance. Despite the similarities to NSAIDs, the mode of action of paracetamol has been uncertain, but it is now generally accepted that it inhibits COX-1 and COX-2 through metabolism by the peroxidase function of these isoenzymes. This results in inhibition of phenoxyl radical formation from a critical tyrosine residue essential for the cyclooxygenase activity of COX-1 and COX-2 and prostaglandin (PG) synthesis. Paracetamol shows selectivity for inhibition of the synthesis of PGs and related factors when low levels of arachidonic acid and peroxides are available but conversely, it has little activity at substantial levels of arachidonic acid and peroxides. The result is that paracetamol does not suppress the severe inflammation of rheumatoid arthritis and acute gout but does inhibit the lesser inflammation resulting from extraction of teeth and is also active in a variety of inflammatory tests in experimental animals. Paracetamol often appears to have COX-2 selectivity. The apparent COX-2 selectivity of action of paracetamol is shown by its poor anti-platelet activity and good gastrointestinal tolerance. Unlike both non-selective NSAIDs and selective COX-2 inhibitors, paracetamol inhibits other peroxidase enzymes including myeloperoxidase. Inhibition of myeloperoxidase involves paracetamol oxidation and concomitant decreased formation of halogenating oxidants (e.g. hypochlorous acid, hypobromous acid) that may be associated with multiple inflammatory pathologies including atherosclerosis and rheumatic diseases. Paracetamol may, therefore, slow the development of these diseases. Paracetamol, NSAIDs and selective COX-2 inhibitors all have central and peripheral effects. As is the case with the NSAIDs, including the selective COX-2 inhibitors, the analgesic effects of paracetamol are reduced by inhibitors of many endogenous neurotransmitter systems including serotonergic, opioid and cannabinoid systems. There is considerable debate about the hepatotoxicity of therapeutic doses of paracetamol. Much of the toxicity may result from overuse of combinations of paracetamol with opioids which are widely used, particularly in USA.

Distinct ATOH1 and Neurog3 requirements define tuft cells as a new secretory cell type in the intestinal epithelium

The unique morphology of tuft cells was first revealed by electron microscopy analyses in several endoderm-derived epithelia. Here, we explore the relationship of these cells with the other cell types of the intestinal epithelium and describe the first marker signature allowing their unambiguous identification. We demonstrate that although mature tuft cells express DCLK1, a putative marker of quiescent stem cells, they are post-mitotic, short lived, derive from Lgr5-expressing epithelial stem cells, and are found in mouse and human tumors. We show that whereas the ATOH1/MATH1 transcription factor is essential for their differentiation, Neurog3, SOX9, GFI1, and SPDEF are dispensable, which distinguishes these cells from enteroendocrine, Paneth, and goblet cells, and raises from three to four the number of secretory cell types in the intestinal epithelium. Moreover, we show that tuft cells are the main source of endogenous intestinal opioids and are the only epithelial cells that express cyclooxygenase enzymes, suggesting important roles for these cells in the intestinal epithelium physiopathology.

Mechanisms of Damage to the Gastrointestinal Tract From Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) can damage the gastrointestinal tract, causing widespread morbidity and mortality. Although mechanisms of damage involve the activities of prostaglandin-endoperoxide synthase 1 (PTGS1 or cyclooxygenase [COX] 1) and PTGS1 (COX2), other factors are involved. We review the mechanisms of gastrointestinal damage induction by NSAIDs via COX-mediated and COX-independent processes. NSAIDs interact with phospholipids and uncouple mitochondrial oxidative phosphorylation, which initiates biochemical changes that impair function of the gastrointestinal barrier. The resulting increase in intestinal permeability leads to low-grade inflammation. NSAID inhibition of COX enzymes, along with luminal aggressors, results in erosions and ulcers, with potential complications of bleeding, protein loss, stricture formation, and perforation. We propose a model for NSAID-induced damage to the gastrointestinal tract that includes these complex, interacting, and inter-dependent factors. This model highlights the obstacles for the development of safer NSAIDs.

Acetaminophen (paracetamol) is a selective cyclooxygenase-2 inhibitor in man

For more than three decades, acetaminophen (INN, paracetamol) has been claimed to be devoid of significant inhibition of peripheral prostanoids. Meanwhile, attempts to explain its action by inhibition of a central cyclooxygenase (COX)-3 have been rejected. The fact that acetaminophen acts functionally as a selective COX-2 inhibitor led us to investigate the hypothesis of whether it works via preferential COX-2 blockade. Ex vivo COX inhibition and pharmacokinetics of acetaminophen were assessed in 5 volunteers receiving single 1000 mg doses orally. Coagulation-induced thromboxane B(2) and lipopolysaccharide-induced prostaglandin E(2) were measured ex vivo and in vitro in human whole blood as indices of COX-1 and COX-2 activity. In vitro, acetaminophen elicited a 4.4-fold selectivity toward COX-2 inhibition (IC(50)=113.7 micromol/L for COX-1; IC(50)=25.8 micromol/L for COX-2). Following oral administration of the drug, maximal ex vivo inhibitions were 56% (COX-1) and 83% (COX-2). Acetaminophen plasma concentrations remained above the in vitro IC(50) for COX-2 for at least 5 h postadministration. Ex vivo IC(50) values (COX-1: 105.2 micromol/L; COX-2: 26.3 micromol/L) of acetaminophen compared favorably with its in vitro IC(50) values. In contrast to previous concepts, acetaminophen inhibited COX-2 by more than 80%, i.e., to a degree comparable to nonsteroidal antiinflammatory drugs (NSAIDs) and selective COX-2 inhibitors. However, a >95% COX-1 blockade relevant for suppression of platelet function was not achieved. Our data may explain acetaminophen's analgesic and antiinflammatory action as well as its superior overall gastrointestinal safety profile compared with NSAIDs. In view of its substantial COX-2 inhibition, recently defined cardiovascular warnings for use of COX-2 inhibitors should also be considered for acetaminophen.

Anti-inflammatory drugs in the 21st century

Historically, anti-inflammatory drugs had their origins in the serendipitous discovery of certain plants and their extracts being applied for the relief of pain, fever and inflammation. When salicylates were discovered in the mid-19th century to be the active components of Willow Spp., this enabled these compounds to be synthesized and from this, acetyl-salicylic acid or Aspirin was developed. Likewise, the chemical advances of the 19th-20th centuries lead to development of the non-steroidal anti-inflammatory drugs (NSAIDs), most of which were initially organic acids, but later non-acidic compounds were discovered. There were two periods of NSAID drug discovery post-World War 2, the period up to the 1970's which was the pre-prostaglandin period and thereafter up to the latter part of the last century in which their effects on prostaglandin production formed part of the screening in the drug-discovery process. Those drugs developed up to the 1980-late 90's were largely discovered empirically following screening for anti-inflammatory, analgesic and antipyretic activities in laboratory animal models. Some were successfully developed that showed low incidence of gastro-intestinal (GI) side effects (the principal adverse reaction seen with NSAIDs) than seen with their predecessors (e.g. aspirin, indomethacin, phenylbutazone); the GI reactions being detected and screened out in animal assays. In the 1990's an important discovery was made from elegant molecular and cellular biological studies that there are two cyclo-oxygenase (COX) enzyme systems controlling the production of prostanoids [prostaglandins (PGs) and thromboxane (TxA2)]; COX-1 that produces PGs and TxA2 that regulate gastrointestinal, renal, vascular and other physiological functions, and COX-2 that regulates production of PGs involved in inflammation, pain and fever. The stage was set in the 1990's for the discovery and development of drugs to selectively control COX-2 and spare the COX-1 that is central to physiological processes whose inhibition was considered a major factor in development of adverse reactions, including those in the GI tract. At the turn of this century, there was enormous commercial development following the introduction of two new highly selective COX-2 inhibitors, known as coxibs (celecoxib and rofecoxib) which were claimed to have low GI side effects. While found to have fulfilled these aims in part, an alarming turn of events took place in the late 2004 period when rofecoxib was withdrawn worldwide because of serious cardiovascular events and other coxibs were subsequently suspected to have this adverse reaction, although to a varying degree. Major efforts are currently underway to discover why cardiovascular reactions took place with coxibs, identify safer coxibs, as well as elucidate the roles of COX-2 and COX-1 in cardiovascular diseases and stroke in the hope that there may be some basis for developing newer agents (e.g. nitric oxide-donating NSAIDs) to control these conditions. The discovery of the COX isoforms led to establishing their importance in many non-arthritic or non-pain states where there is an inflammatory component to pathogenesis, including cancer, Alzheimer's and other neurodegenerative diseases. The applications of NSAIDs and the coxibs in the prevention and treatment of these conditions as well as aspirin and other analogues in the prevention of thrombo-embolic diseases now constitute one of the major therapeutic developments of the this century. Moreover, new anti-inflammatory drugs are being discovered and developed based on their effects on signal transduction and as anti-cytokine agents and these drugs are now being heralded as the new therapies to control those diseases where cytokines and other nonprostaglandin components of chronic inflammatory and neurodegenerative diseases are manifest. To a lesser extent safer application of corticosteroids and the applications of novel drug delivery systems for use with these drugs as well as with NSAIDs also represent newer technological developments of the 21st century. What started out as drugs to control inflammation, pain and fever in the last two centuries now has exploded to reveal an enormous range and type of anti-inflammatory agents and discovery of new therapeutic targets to treat a whole range of conditions that were never hitherto envisaged.

GPR109A (PUMA-G/HM74A) mediates nicotinic acid-induced flushing

Nicotinic acid (niacin) has long been used as an antidyslipidemic drug. Its special profile of actions, especially the rise in HDL-cholesterol levels induced by nicotinic acid, is unique among the currently available pharmacological tools to treat lipid disorders. Recently, a G-protein-coupled receptor, termed GPR109A (HM74A in humans, PUMA-G in mice), was described and shown to mediate the nicotinic acid-induced antilipolytic effects in adipocytes. One of the major problems of the pharmacotherapeutical use of nicotinic acid is a strong flushing response. This side effect, although harmless, strongly affects patient compliance. In the present study, we show that mice lacking PUMA-G did not show nicotinic acid-induced flushing. In addition, flushing in response to nicotinic acid was also abrogated in the absence of cyclooxygenase type 1, and mice lacking prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) receptors had reduced flushing responses. The mouse orthologue of GPR109A, PUMA-G, is highly expressed in macrophages and other immune cells, and transplantation of wild-type bone marrow into irradiated PUMA-G-deficient mice restored the nicotinic acid-induced flushing response. Our data clearly indicate that GPR109A mediates nicotinic acid-induced flushing and that this effect involves release of PGE(2) and PGD(2), most likely from immune cells of the skin.

Mesenchymal stem cells induce resistance to chemotherapy through the release of platinum-induced fatty acids

The development of resistance to chemotherapy is a major obstacle for lasting effective treatment of cancer. Here, we demonstrate that endogenous mesenchymal stem cells (MSCs) become activated during treatment with platinum analogs and secrete factors that protect tumor cells against a range of chemotherapeutics. Through a metabolomics approach, we identified two distinct platinum-induced polyunsaturated fatty acids (PIFAs), 12-oxo-5,8,10-heptadecatrienoic acid (KHT) and hexadeca-4,7,10,13-tetraenoic acid (16:4(n-3)), that in minute quantities induce resistance to a broad spectrum of chemotherapeutic agents. Interestingly, blocking central enzymes involved in the production of these PIFAs (cyclooxygenase-1 and thromboxane synthase) prevents MSC-induced resistance. Our findings show that MSCs are potent mediators of resistance to chemotherapy and reveal targets to enhance chemotherapy efficacy in patients.

Regulation of intracellular cyclooxygenase levels by gene transcription and protein degradation

Cyclooxygenases-1 and -2 (COX-1 and -2) catalyze the committed step in prostaglandin formation. Each isozyme subserves different biological functions. This is, at least in part, a consequence of differences in patterns of COX-1 and COX-2 expression. COX-1 is induced during development, and COX-1 mRNA and COX-1 protein are very stable. These latter properties can explain why COX-1 protein levels usually remain constant in those cells that express this isozyme. COX-2 is usually expressed inducibly in association with cell replication or differentiation. Both COX-2 mRNA and COX-2 protein have short half-lives relative to those of COX-1. Therefore, COX-2 protein is typically present for only a few hours after its synthesis. Here we review and develop the concepts that (a) COX-2 gene transcription can involve at least six different cis-acting promoter elements interacting with trans-acting factors generated by multiple, different signaling pathways, (b) the relative contribution of each cis-acting COX-2 promoter element depends on the cell type, the stimulus and the time following the stimulus and (c) a unique 27 amino acid instability element located just upstream of the C-terminus of COX-2 targets this isoform to the ER-associated degradation system and proteolysis by the cytosolic 26S proteasome.

Synthesis and biological evaluation of some thiazolyl and thiadiazolyl derivatives of 1H-pyrazole as anti-inflammatory antimicrobial agents

Four series of pyrazolyl benzenesulfonamide derivatives have been synthesized. The first series was prepared by cyclization of the intermediate N,N-dimethylaminomethylene-4[3-phenyl-4-(substituted thiosemicarbamoyl hydrazonomethyl)-1H-pyrazol-1-yl]benzenesulfonamide 2a-c with ethyl bromoacetate to afford the corresponding thiazolidinyl derivatives 3a-c. The second series was prepared by cyclization of the key intermediates 2a-c with 4-bromophenacyl bromide giving rise to thiazolinyl derivatives 4a-c. Thiadiazolyl derivatives 5a-c were obtained by heating 2a-c with 2M FeCl(3) solution. Refluxing the intermediates 2a-c in acetic anhydride yielded the corresponding thiadiazolinyl derivatives 6a-c. All the target compounds showed anti-inflammatory activity and three of them 3b, 3c and 4c surpassed that of indomethacin both locally and systemically in the cotton pellet granuloma and rat paw edema bioassay. The active compounds showed selective inhibitory activity towards COX-2 enzyme as revealed by the in vitro enzymatic assay. All the tested compounds proved to have superior gastrointestinal (GI) safety profiles as compared to indomethacin, when tested for their ulcerogenic effects. The acute toxicity study of compounds having promising anti-inflammatory activity (3b, 3c and 4c) indicated that they are well tolerated both orally and parenterally. Antimicrobial activity tests expressed as minimal inhibitory concentrations (MIC), revealed that compounds 3b and 4a showed comparable antibacterial activity to that of ampicillin against Escherichia coli, while compounds 3a, 3c and 4a possessed about half the activity of ampicillin against Staphylococcus aureus. On the other hand, the results showed that all the tested compounds have weak or no antifungal activity against Candida albicans except for compounds 6b and 6c that showed half the activity of the control antifungal drug used (clotrimazole).

Uptake and biological effects of environmentally relevant concentrations of the nonsteroidal anti-inflammatory pharmaceutical diclofenac in rainbow trout (Oncorhynchus mykiss)

Diclofenac, a nonsteroidal anti-inflammatory drug, is widely detected in surface waters and can potentially cause deleterious effects in fish. Here, we investigated the biological effects of 21-day exposure to waterborne diclofenac at environmentally relevant concentrations (0, 0.5, 1, 5, and 25 μg/L) in rainbow trout Accumulation of diclofenac in the bile was measured and responses in selected tissues were assessed via changes in the expression of selected genes (cytochrome P450 (cyp) 1a1, cyclooxygenase (cox) 1 and 2, and p53) involved in metabolism of xenobiotics, prostaglandin synthesis, and cell cycle control, respectively, together with histopathological alterations in these tissues. Diclofenac accumulated in the bile by a factor of between 509 ± 27 and 657 ± 25 and various metabolites were putatively identified as hydroxydiclofenac, diclofenac methyl ester, and the potentially reactive metabolite hydroxydiclofenac glucuronide. Expression levels of both cox1 and cox2 in liver, gills, and kidney were significantly reduced by diclofenac exposure from only 1 μg/L. Expression of cyp1a1 was induced in the liver and the gills but inhibited in the kidney of exposed fish. Diclofenac exposure induced tubular necrosis in the kidney and hyperplasia and fusion of the villi in the intestine from 1 μg/L. This study demonstrates that subchronic exposure to environmental concentrations of diclofenac can interfere with the biochemical functions of fish and lead to tissue damage, highlighting further the concern about this pharmaceutical in the aquatic environment.

Gastrointestinal safety and anti-inflammatory effects of a hydrogen sulfide-releasing diclofenac derivative in the rat

BACKGROUND & AIMS

Gastrointestinal damage caused by nonsteroidal anti-inflammatory drugs (NSAIDs) remains a significant clinical problem. Hydrogen makes an important contribution to mucosal defense, and NSAIDs can suppress its synthesis. In this study, we evaluated the gastrointestinal safety and anti-inflammatory effects of a novel "HS-NSAID" (ATB-337) that consists of diclofenac linked to a hydrogen sulfide-releasing moiety.

METHODS

The gastrointestinal injury-inducing effects of single or repeated administration of diclofenac versus ATB-337 were compared in rats, as were their effects on prostaglandin synthesis and cyclooxygenase-1 and -2 activities. The ability of these drugs to reduce carrageenan-induced paw edema and to elicit leukocyte adherence to the vascular endothelium (intravital microscopy) were also examined in rats.

RESULTS

Diclofenac (10-50 micromol/kg) dose-dependently damaged the stomach, while ATB-337 did not. Repeated administration of diclofenac caused extensive small intestinal damage and reduced hematocrit by 50%. ATB-337 induced >90% less intestinal damage and had no effect on hematocrit. Diclofenac, but not ATB-337, elevated gastric granulocyte infiltration and expression of tumor necrosis factor alpha, lymphocyte function-associated antigen 1, and intercellular adhesion molecule 1. ATB-337 inhibited cycloxygenase-1 and cyclooxygenase-2 activity as effectively as diclofenac. ATB-337 did not induce leukocyte adherence, whereas diclofenac did, and was more potent at reducing paw edema.

CONCLUSIONS

An HS-NSAID spares the gastric mucosa of injury despite markedly suppressing prostaglandin synthesis. This effect may be related to hydrogen sulfide-mediated inhibition of tumor necrosis factor-alpha expression and of the leukocyte adherence to vascular endothelium normally induced by cyclooxygenase inhibitors.

Nuclear factor-{kappa}B activation contributes to vascular endothelial dysfunction via oxidative stress in overweight/obese middle-aged and older humans

BACKGROUND

We tested the hypothesis that nuclear factor-kappaB (NF-kappaB) activity contributes to vascular endothelial dysfunction with aging and obesity in humans.

METHODS AND RESULTS

We conducted a randomized, double-blind, placebo-controlled crossover study in 14 nondiabetic overweight or obese (body mass index > or =25 kg/m(2)) middle-aged and older (age 52 to 68 years) adults. Salsalate (nonacetylated salicylate, 4500 mg/d), a compound that inhibits NF-kappaB activity, or placebo was administered for 4-day periods. Plasma salicylate concentrations reached the midtherapeutic range (21.8+/-1.1 mg/100 mL, P< or =0.0001 versus placebo) by day 4 of salsalate treatment. Salsalate increased expression of the inhibitor of NF-kappaB and reduced total and nuclear expression of NF-kappaB in endothelial cells obtained from the subjects (all P<0.05). Salsalate increased brachial artery flow-mediated dilation by 74% (from 4.0+/-0.4% to 6.6+/-0.5%, P<0.001) but did not affect endothelium-independent dilation (P=0.83). The change in brachial artery flow-mediated dilation with salsalate was inversely related to baseline flow-mediated dilation (r=-0.77, P<0.01). Infusion of vitamin C increased brachial artery flow-mediated dilation during placebo (P<0.001) but not after salsalate (P=0.23). Salsalate reduced nitrotyrosine (P=0.06) and expression of NADPH oxidase p47(phox) (P<0.05) in endothelial cells obtained from the subjects but did not influence circulating or endothelial cell inflammatory proteins.

CONCLUSIONS

Our findings provide the first direct evidence that NF-kappaB, in part via stimulation of oxidative stress, plays an important role in mediating vascular endothelial dysfunction in overweight and obese middle-aged and older humans.

PGC-1alpha is not mandatory for exercise- and training-induced adaptive gene responses in mouse skeletal muscle

The aim of the present study was to test the hypothesis that peroxisome proliferator activated receptor-gamma coactivator (PGC) 1alpha is required for exercise-induced adaptive gene responses in skeletal muscle. Whole body PGC-1alpha knockout (KO) and littermate wild-type (WT) mice performed a single treadmill-running exercise bout. Soleus and white gastrocnemius (WG) were obtained immediately, 2 h, or 6 h after exercise. Another group of PGC-1alpha KO and WT mice performed 5-wk exercise training. Soleus, WG, and quadriceps were obtained approximately 37 h after the last training session. Resting muscles of the PGC-1alpha KO mice had lower ( approximately 20%) cytochrome c (cyt c), cytochrome oxidase (COX) I, and aminolevulinate synthase (ALAS) 1 mRNA and protein levels than WT, but similar levels of AMP-activated protein kinase (AMPK) alpha1, AMPKalpha2, and hexokinase (HK) II compared with WT mice. A single exercise bout increased phosphorylation of AMPK and acetyl-CoA carboxylase-beta and the level of HKII mRNA similarly in WG of KO and WT. In contrast, cyt c mRNA in soleus was upregulated in WT muscles only. Exercise training increased cyt c, COXI, ALAS1, and HKII mRNA and protein levels equally in WT and KO animals, but cyt c, COXI, and ALAS1 expression remained approximately 20% lower in KO animals. In conclusion, lack of PGC-1alpha reduced resting expression of cyt c, COXI, and ALAS1 and exercise-induced cyt c mRNA expression. However, PGC-1alpha is not mandatory for training-induced increases in ALAS1, COXI, and cyt c expression, showing that factors other than PGC-1alpha can exert these adaptations.

COX isoforms in the cardiovascular system: understanding the activities of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the formation of prostanoids by the enzyme cyclooxygenase (COX). Work in the past 15 years has shown that COX exists in two forms: COX1, which is largely associated with physiological functions, and COX2, which is largely associated with pathological functions. Heated debate followed the introduction of selective COX2 inhibitors around 5 years ago: do these drugs offer any advantages over the traditional NSAIDs theywere meant to replace, particularly in regard to gastrointestinal and cardiovascular side effects? Here we discuss the evidence and the latest recommendations for the use of selective inhibitors of COX2 as well as the traditional NSAIDs.

Reticulated platelets and uninhibited COX-1 and COX-2 decrease the antiplatelet effects of aspirin

BACKGROUND

The mechanisms for the variability in antiplatelet effects of aspirin are unclear. Immature (reticulated) platelets may modulate the antiplatelet effects of aspirin through uninhibited cyclooxygenase (COX)-1 and COX-2.

OBJECTIVES

To evaluate the role of reticulated platelets in the antiplatelet effects of aspirin.

METHODS

Sixty healthy volunteers had platelet studies performed before and 24 h after a single 325-mg dose of aspirin. Platelet studies included light transmission aggregometry; P-selectin and integrin alpha(IIb)beta(3) expression, and serum thromboxane B(2) (TxB(2)) levels. Reticulated platelets and platelet COX-2 expression were measured using flow cytometry.

RESULTS

Subjects were divided into tertiles based on the percentage of reticulated platelets in whole blood. Baseline platelet aggregation to 1 microg mL(-1) collagen, and postaspirin aggregations to 5 microm and 20 microm ADP and collagen, were greater in the upper than in the lower tertile of reticulated platelets. Stimulated P-selectin and integrin alpha(IIb)beta(3) expression were also higher in the upper tertile both before and after aspirin. Platelet COX-2 expression was detected in 12 +/- 7% (n = 10) of platelets in the upper tertile, and in 7 +/- 3% (n = 12) of platelets in the lower two tertiles (P = 0.03). Postaspirin serum TxB(2) levels were higher in the upper (5.5 +/- 4 ng mL(-1)) than in the lower tertile (3.2 +/- 2.5 ng mL(-1), P = 0.03), and decreased even further with ex vivo additional COX-1 and COX-2 inhibition. The incidence of aspirin resistance (>or= 70% platelet aggregation to 5 microm ADP) was significantly higher in the upper tertile (45%) than in the lower tertile (5%, P < 0.0001).

CONCLUSIONS

Reticulated platelets are associated with diminished antiplatelet effects of aspirin and increased aspirin resistance, possibly because of increased reactivity, and uninhibited COX-1 and COX-2 activity.

The effects of resveratrol, a phytoalexin derived from red wines, on chronic inflammation induced in an experimentally induced colitis model

Neutrophil infiltration, proinflammatory cytokines, eicosanoid generation and oxidative stress have been implicated in colitis. Resveratrol is a polyphenolic compound found in grapes and wine, with multiple pharmacological actions, including anti-inflammatory, antioxidant, antitumour and immunomodulatory activities. In a previous report, we documented that resveratrol decreases the degree of inflammation associated with acute experimental colonic inflammation, but its effects on chronic experimental colitis remain undetermined. The aim of this research was to investigate the effects of resveratrol on the chronic colonic injury caused by intracolonic instillation of trinitrobenzenesulphonic acid (TNBS) in rats. The inflammatory response was assessed by histology and myeloperoxidase activity. Tumour necrosis factor alpha (TNF-alpha) production, histological and histochemical analysis of the lesions were also carried out. We determined the production of prostaglandin (PG) E2 and D2 in colon mucosa, as well as cyclooxygenase (COX)-1 and -2 and nuclear transcription factor NF-kappa B (NF-kappaB) p65 protein expression. Finally, since resveratrol has been found to modulate apoptosis, we intended to elucidate its effects on colonic mucosa under chronic inflammatory conditions. Resveratrol (10 mg kg(-1) day(-1)) significantly attenuated the damage score and corrected the disturbances in morphology associated to injury. In addition, the degree of neutrophil infiltration and the levels of TNF-alpha were significantly ameliorated. Resveratrol did not modify PGD2 levels but returned the decreased PGE2 values to basal levels and also reduced COX-2 and the NF-kappaB p65 protein expression. Furthermore, treatment of rats with resveratrol caused a significant increase of TNBS-induced apoptosis in colonic cells. In conclusion, resveratrol reduces the damage in chronic experimentally induced colitis, alleviates the oxidative events, returns PGE2 production to basal levels and stimulates apoptosis in colonic cells.

Targeting cyclooxygenases-1 and -2 in neuroinflammation: Therapeutic implications

Neuroinflammation has been implicated in the pathogenesis or the progression of a variety of acute and chronic neurological and neurodegenerative disorders, including Alzheimer's disease. Prostaglandin H synthases or cyclooxygenases (COX -1 and COX-2) play a central role in the inflammatory cascade by converting arachidonic acid into bioactive prostanoids. In this review, we highlighted recent experimental data that challenge the classical view that the inducible isoform COX-2 is the most appropriate target to treat neuroinflammation. First, we discuss data showing that COX-2 activity is linked to anti-inflammatory and neuroprotective actions and is involved in the generation of novel lipid mediators with pro-resolution properties. Then, we review recent data demonstrating that COX-1, classically viewed as the homeostatic isoform, is actively involved in brain injury induced by pro-inflammatory stimuli including Aβ, lipopolysaccharide, IL-1β, and TNF-α. Overall, we suggest revisiting the traditional views on the roles of each COX during neuroinflammation and we propose COX-1 inhibition as a viable therapeutic approach to treat CNS diseases with a marked inflammatory component.

Selective synthesis and biological evaluation of sulfate-conjugated resveratrol metabolites

Five resveratrol sulfate metabolites were synthesized and assessed for activities known to be mediated by resveratrol: inhibition of tumor necrosis factor (TNF) alpha induced NFkappaB activity, cylcooxygenases (COX-1 and COX-2), aromatase, nitric oxide production in endotoxin-stimulated macrophages, proliferation of KB or MCF7 cells, induction of quinone reductase 1 (QR1), accumulation in the sub-G(1) phase of the cell cycle, and quenching of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. Two metabolites showed activity in these assays; the 3-sulfate exhibited QR1 induction, DPPH free radical scavenging, and COX-1 and COX-2 inhibitory activities and the 4'-sulfate inhibited NFkappaB induction, as well as COX-1 and COX-2 activities. Resveratrol and its 3'-sulfate and 4-sulfate inhibit NO production by NO scavenging and down-regulation of iNOS expression in RAW 264.7 cells. Resveratrol sulfates displayed low antiproliferative activity and negligible uptake in MCF7 cells.

Enhancement of antinociception by coadministration of nonsteroidal anti-inflammatory drugs and soluble epoxide hydrolase inhibitors

Combination therapies have long been used to treat inflammation while reducing side effects. The present study was designed to evaluate the therapeutic potential of combination treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and previously undescribed soluble epoxide hydrolase inhibitors (sEHIs) in lipopolysaccharide (LPS)-challenged mice. NSAIDs inhibit cyclooxygenase (COX) enzymes and thereby decrease production of metabolites that lead to pain and inflammation. The sEHIs, such as 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester (AUDA-BE), stabilize anti-inflammatory epoxy-eicosatrienoic acids, which indirectly reduce the expression of COX-2 protein. Here we demonstrate that the combination therapy of NSAIDs and sEHIs produces significantly beneficial effects that are additive for alleviating pain and enhanced effects in reducing COX-2 protein expression and shifting oxylipin metabolomic profiles. When administered alone, AUDA-BE decreased protein expression of COX-2 to 73 +/- 6% of control mice treated with LPS only without altering COX-1 expression and decreased PGE(2) levels to 52 +/- 8% compared with LPS-treated mice not receiving any therapeutic intervention. When AUDA-BE was used in combination with low doses of indomethacin, celecoxib, or rofecoxib, PGE(2) concentrations dropped to 51 +/- 7, 84 +/- 9, and 91 +/- 8%, respectively, versus LPS control, without disrupting prostacyclin and thromboxane levels. These data suggest that these drug combinations (NSAIDs and sEHIs) produce a valuable beneficial analgesic and anti-inflammatory effect while prospectively decreasing side effects such as cardiovascular toxicity.