391 results found
Ahmetaj-Shala B, Kawai R, Marei I, et al., 2020, A bioassay system of autologous human endothelial, smooth muscle cells and leucocytes for use in drug discovery, phenotyping and tissue engineering, The FASEB Journal, Vol: 34, Pages: 1745-1754, ISSN: 0892-6638
Purpose: Blood vessels are comprised of endothelial and smooth muscle cells. Obtaining both types of cells from vessels of living donors is not possible without invasive surgery. To address this we have devised a strategy whereby human endothelial and smooth muscle cells derived from blood progenitors from the same donor could be cultured with autologous leucocytes to generate a same donor ‘vessel in a dish’ bioassay. Basic procedures: Autologous sets of blood outgrowth endothelial cells (BOECs), smooth muscle cells (BO-SMCs) and leucocytes were obtained from 4 donors. Cells were treated in mono and cumulative co-culture conditions. The endothelial specific mediator endothelin-1 along with interleukin (IL)-6, IL-8, tumour necrosis factor α, and interferon gamma-induced protein 10 were measured under control culture conditions and after stimulation with cytokines.Main findings: Co-cultures remained viable throughout. The profile of individual mediators released from cells was consistent with what we know of endothelial and smooth muscle cells cultured from blood vessels.Principle conclusions: For the first time, we report a proof of concept study where autologous blood outgrowth ‘vascular’ cells and leucocytes were studied alone and in co-culture. This novel bioassay has utility in vascular biology research, patient phenotyping, drug testing and tissue engineering.
Kirkby N, Raouf J, Ahmetaj-Shala B, et al., 2019, Mechanistic definition of the cardiovascular mPGES-1/COX-2/ADMA axis, Cardiovascular Research, ISSN: 0008-6363
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 eNOS, 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 compartmentalisation 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.Conclusions:These data demonstrate that inhibition of mPGES-1 spares the renal COX-2/ADMA pathway and define mechanistically how COX-2 regulates ADMA.
Mitchell J, Shala F, Elghazouli Y, et al., 2019, Cell-Specific Gene Deletion Reveals the Antithrombotic Function of COX1 and Explains the Vascular COX1/Prostacyclin Paradox, Circulation Research, Vol: 125, Pages: 847-854, ISSN: 0009-7330
Rationale: Endothelial cells and platelets, which respectively produce anti-thrombotic prostacyclin and pro-thrombotic thromboxane A2, both express COX1. Consequently, there has been no way to delineate any anti-thrombotic role for COX1-derived prostacyclin from the pro-thrombotic effects of platelet COX1. By contrast an anti-thrombotic role for COX2, which is absent in platelets, is straightforward to demonstrate. This has resulted in an incomplete understanding of the relative importance of COX1 versus COX2 in prostacyclin production and anti-thrombotic protection in vivo.Objective: We sought to identify the role, if any, of COX1-derived prostacyclin in anti-thrombotic protection in vivo and compare this to the established protective role of COX2.Methods and Results: We developed vascular-specific COX1 knockout mice and studied them alongside endothelial-specific COX2 knockout mice. COX1 immunoreactivity and prostacyclin production were primarily associated with the endothelial layer of aortae; freshly isolated aortic endothelial cells released >10-fold more prostacyclin than smooth muscle cells. Moreover, aortic prostacyclin production, the ability of aortic rings to inhibit platelet aggregation and plasma prostacyclin levels were reduced when COX1 was knocked out in endothelial cells but not in smooth muscle cells. When thrombosis was measured in vivo after FeCl3 carotid artery injury, endothelial COX1 deletion accelerated thrombosis to a similar extent as prostacyclin receptor blockade. However, but this effect was lost when COX1 was deleted from both endothelial cells and platelets. Deletion of COX2 from endothelial cells also resulted in a pro-thrombotic phenotype that was independent of local vascular prostacyclin production.Conclusions:These data demonstrate for the first time that, in healthy animals, endothelial COX1 provides an essential anti-thrombotic tone, which is masked when COX1 activity is lost in both endothelial cells and platelets. These res
George PM, Mitchell JA, 2019, Defining a pathological role for the vasculature in the development of fibrosis and pulmonary hypertension in interstitial lung disease, AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY, Vol: 317, Pages: L431-L433, ISSN: 1040-0605
Marei I, Mongey R, Gashaw H, et al., 2019, Isolation of blood outgrowth endothelial cells under shear conditions: A move towards a more physiological vascular cell platform, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 3033-3033, ISSN: 0007-1188
Ahmetaj-Shala B, Kawai R, Marei I, et al., 2019, A bioassay system of autologous human endothelial and smooth muscle cells for use in cardiovascular drug discovery and patient phenotyping, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 3040-3041, ISSN: 0007-1188
Mohamed NA, Davies RP, Lickiss PD, et al., 2019, Mil-89 nanoformulation as a platform to improve pulmonary arterial hypertension treatment, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 3075-3075, ISSN: 0007-1188
Marei I, Al Shammari H, Latif N, et al., 2019, Effect of toll-like receptor antagonists on side specific aortic valve endothelial cells, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 2999-3000, ISSN: 0007-1188
Mazi SI, Ahmetaj-Shala B, Warner TD, et al., 2019, Omic profiling in healthy volunteers taking celecoxib reveals novel biomarkers regulated by cyclooxygenase-2, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 1628-1628, ISSN: 0306-5251
Ciano M, Mantellato G, Connolly M, et al., 2019, EGF receptor (EGFR) inhibition promotes a slow-twitch oxidative, over a fast-twitch, muscle phenotype, Scientific Reports, Vol: 9, ISSN: 2045-2322
A low quadriceps slow-twitch (ST), oxidative (relative to fast-twitch) fiber proportion is prevalent in chronic diseases such Chronic Obstructive Pulmonary Disease (COPD) and is associated with exercise limitation and poor outcomes. Benefits of an increased ST fiber proportion are demonstrated in genetically modified animals. Pathway analysis of published data of differentially expressed genes in mouse ST and FT fibers, mining of our microarray data and a qPCR analysis of quadriceps specimens from COPD patients and controls were performed. ST markers were quantified in C2C12 myotubes with EGF-neutralizing antibody, EGFR inhibitor or an EGFR-silencing RNA added. A zebrafish egfra mutant was generated by genome editing and ST fibers counted. EGF signaling was (negatively) associated with the ST muscle phenotype in mice and humans, and muscle EGF transcript levels were raised in COPD. In C2C12 myotubes, EGFR inhibition/silencing increased ST, including mitochondrial, markers. In zebrafish, egfra depletion increased ST fibers and mitochondrial content. EGF is negatively associated with ST muscle phenotype in mice, healthy humans and COPD patients. EGFR blockade promotes the ST phenotype in myotubes and zebrafish embryos. EGF signaling suppresses the ST phenotype, therefore EGFR inhibitors may be potential treatments for COPD-related muscle ST fiber loss.
Lucotti S, Cerutti C, Soyer M, et al., 2019, Aspirin blocks formation of metastatic intravascular niches by inhibiting platelet-derived COX-1/thromboxane A(2), JOURNAL OF CLINICAL INVESTIGATION, Vol: 129, Pages: 1845-1862, ISSN: 0021-9738
Akhmedov D, Kirkby NS, Mitchell JA, et al., 2019, Imaging of Tissue-Specific and Temporal Activation of GPCR Signaling Using DREADD Knock-In Mice., Pages: 361-376
Engineered G protein-coupled receptors (DREADDs, designer receptors exclusively activated by designer drugs) are convenient tools for specific activation of GPCR signaling in many cell types. DREADDs have been utilized as research tools to study numerous cellular and physiologic processes, including regulation of neuronal activity, behavior, and metabolism. Mice with random insertion transgenes and adeno-associated viruses have been widely used to express DREADDs in individual cell types. We recently created and characterized ROSA26-GsDREADD knock-in mice to allow Cre recombinase-dependent expression of a Gαs-coupled DREADD (GsD) fused to GFP in distinct cell populations in vivo. These animals also harbor a CREB-activated luciferase reporter gene for analysis of CREB activity by in vivo imaging, ex vivo imaging, or biochemical reporter assays. In this chapter, we provide detailed methods for breeding GsD animals, inducing GsD expression, stimulating GsD activity, and measuring basal and stimulated CREB reporter bioluminescence in tissues in vivo, ex vivo, and in vitro. These animals are available from our laboratory for non-profit research.
Mitchell J, Kirkby NS, 2019, Eicosanoids, prostacyclin and cyclooxygenase in the cardiovascular system, British Journal of Pharmacology, Vol: 176, Pages: 1038-1050, ISSN: 1476-5381
Eicosanoids represent a diverse family of lipid mediators with fundamental roles in controlling physiology and disease. Within the eicosanoid super family are prostanoids, which are specifically derived from arachidonic acid by the enzyme cyclooxygenase(COX). COX has two isoforms; COX-1 and COX-2. COX-2 is the therapeutic target for the nonsteroidal anti-inflammatory drug (NSAID) class of pain medications. Of the prostanoids,prostacyclin, first discovered by Sir Professor John Vane in 1976,remains amongst the best studied and retains an impressive pedigree as onethe bodies fundamental cardiovascular protective pathways. Since this time, we have learnt much about how eicosanoids, COXenzymes and prostacyclin function in the cardiovascular system which has allowed us to, for example, harness the power of prostacyclin as therapy to treat pulmonary arterial hypertension and peripheral vascular disease. However, there remain many unanswered questions in our basic understanding of the pathways and how they can be usedto improve human health. Perhaps the most importantand controversial outstanding question in the field remains;‘how do NSAIDsproduce their much publicized cardiovascular side effects?’This review summarises the history, biology and cardiovascular function of key eicosanoids with particular focus on prostacyclin and other COXproducts and discusses how our knowledge of these pathways can applied in future drug discovery and be used to explain the cardiovascular side effects of NSAIDs.
Alvarez-Fuente M, Moreno L, Mitchell JA, et al., 2019, Preventing bronchopulmonary dysplasia: new tools for an old challenge, PEDIATRIC RESEARCH, Vol: 85, Pages: 432-441, ISSN: 0031-3998
Mitchell JA, Bishop-Bailey D, 2019, PPARβ/δ a potential target in pulmonary hypertension blighted by cancer risk, Pulmonary Circulation, Vol: 9, Pages: 1-2, ISSN: 2045-8940
Mitchell J, Bishop-Bailey D, PPARβ/δ a potential target in pulmonary hypertension blighted by cancer risk., Pulmonary Circulation, ISSN: 2045-8940
Dear Editor,Our group and others have used preclinical in vitro and in vivo models that highlight the potential therapeutic benefit of PPARβ/δ as a target in the treatment of pulmonary arterial hypertension. Selective agonists of PPARβ/δ inhibit fibroblast and pulmonary arterial vascular smooth muscle cell growth and prevent right heart hypertrophy in rat models of pulmonary arterial hypertension. Further work published in Pulmonary Circulation established the transcriptomic profile and pathways associated with activating PPARβ/δ in a model of pulmonary artery banding and right heart hypertrophy (1). These results and the fact that enhancing PPARβ/δ is linked to increased endurance exercise performance (2) supports the idea that drugs working on this pathway could be beneficial in pulmonary arterial hypertension. However, there is cause for concern regarding at least one drug that activates PPARβ/δ, GW501516, developed by GlaxoSmithKline plc (GSK) in the early 2000’s. Despite these concerns and although not confirmed in humans, following the publication of endurance exercise studies in rodents, a significant underground market has developed for unlicensed GW501516 (also referred to as Endurobol or Cardarine) in a bid to enhance human athletic performance. PPARβ/δ agonists, including GW501516 were developed for the treatment of hyperlipidemia and other cardiovascular diseases and a number of clinical trails have been registered on clinicaltrials.gov (Clinical trials id NCT00388180; NCT00318617; NCT00158899; NCT00841217). Whilst, long term clinical data are not available, GW501516 improved lipid profiles in short term studies in man (3-5). However safety concerns over GW501516 and potentially other drugs in the class have emerged. Of particular relevance are two abstracts from GSK showing that GW501516 causes cancer in rats (6) and mice (7) after 104 weeks of dosing. Although, neither of these stu
Kawai R, Ahmetaj-Shala B, Shih CC, et al., 2018, Development of a human autologous 3-cell cytokine release assay that models the vascular wall in vitro, 54th Congress of the European-Societies-of-Toxicology (EUROTOX) - Toxicology Out of the Box, Publisher: ELSEVIER IRELAND LTD, Pages: S114-S114, ISSN: 0378-4274
Ahmetaj-Shala B, Olanipekun M, Tesfai A, et al., 2018, Development of a novel UPLC-MS/MS-based platform to quantify amines, amino acids and methylarginines for applications in human disease phenotyping, Scientific Reports, Vol: 8, ISSN: 2045-2322
Amine quantification is an important strategy in patient stratification and personalised medicine. This is because amines, including amino acids and methylarginines impact on many homeostatic processes. One important pathway regulated by amine levels is nitric oxide synthase (NOS). NOS is regulated by levels of (i) the substrate, arginine, (ii) amino acids which cycle with arginine and (iii) methylarginine inhibitors of NOS. However, biomarker research in this area is hindered by the lack of a unified analytical platform. Thus, the development of a common metabolomics platform, where a wide range of amino acids and methylarginines can be measured constitutes an important unmet need. Here we report a novel high-throughput ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) platform where ≈40 amine analytes, including arginine and methylarginines can be detected and quantified on a molar basis, in a single sample of human plasma. To validate the platform and to generate biomarkers, human plasma from a well-defined cohort of patients before and after coronary artery bypass surgery, who developed systemic inflammatory response syndrome (SIRS), were analysed. Bypass surgery with SIRS significantly altered 26 amine analytes, including arginine and ADMA. Consequently, pathway analysis revealed significant changes in a range of pathways including those associated with NOS.
Mitchell JA, Knowles RB, Kirkby NS, et al., 2018, Letter by Mitchell et al Regarding Article, "Urinary Prostaglandin Metabolites: An Incomplete Reckoning and a Flush to Judgment"., Circulation Research, Vol: 122, Pages: e84-e85, ISSN: 0009-7330
Kirkby NS, Sampaio W, Etelvino G, et al., 2018, Cyclooxygenase-2 Selectively Controls Renal Blood Flow Through a Novel PPAR beta/delta-Dependent Vasodilator Pathway (vol 71, pg 297, 2018), HYPERTENSION, Vol: 71, Pages: e10-e10, ISSN: 0194-911X
Mitchell JA, Knowles RB, Kirkby NS, et al., 2018, Kidney Transplantation in a Patient Lacking Cytosolic Phospholipase A2Proves Renal Origins of Urinary PGI-M and TX-M., Circulation Research, Vol: 122, Pages: 555-559, ISSN: 0009-7330
RATIONALE: The balance between vascular prostacyclin, which is antithrombotic, and platelet thromboxane A2, which is prothrombotic, is fundamental to cardiovascular health. Prostacyclin and thromboxane A2are formed after the concerted actions of cPLA2α (cytosolic phospholipase A2) and COX (cyclooxygenase). Urinary 2,3-dinor-6-keto-PGF1α(PGI-M) and 11-dehydro-TXB2(TX-M) have been taken as biomarkers of prostacyclin and thromboxane A2formation within the circulation and used to explain COX biology and patient phenotypes, despite concerns that urinary PGI-M and TX-M originate in the kidney. OBJECTIVE: We report data from a remarkable patient carrying an extremely rare genetic mutation in cPLA2α, causing almost complete loss of prostacyclin and thromboxane A2, who was transplanted with a normal kidney resulting in an experimental scenario of whole-body cPLA2α knockout, kidney-specific knockin. By studying this patient, we can determine definitively the contribution of the kidney to the productions of PGI-M and TX-M and test their validity as markers of prostacyclin and thromboxane A2in the circulation. METHODS AND RESULTS: Metabolites were measured using liquid chromatography-tandem mass spectrometry. Endothelial cells were grown from blood progenitors. Before kidney transplantation, the patient's endothelial cells and platelets released negligible levels of prostacyclin (measured as 6-keto-prostaglandin F1α) and thromboxane A2(measured as TXB2), respectively. Likewise, the urinary levels of PGI-M and TX-M were very low. After transplantation and the establishment of normal renal function, the levels of PGI-M and TX-M in the patient's urine rose to within normal ranges, whereas endothelial production of prostacyclin and platelet production of thromboxane A2remained negligible. CONCLUSIONS: These data show that PGI-M and TX-M can be derived exclusively from the kidney without contribution from prostacyclin made by endothelial cells or thromb
Kirkby NS, Sampaio W, Etelvino G, et al., 2018, Cyclooxygenase-2 selectively controls renal blood flow through a novel PPARβ/δ-dependent renal vasodilator pathway, Hypertension, Vol: 71, Pages: 297-305, ISSN: 0194-911X
Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in inflammation and cancer targeted by nonsteroidal anti-inflammatory drugs. COX-2 is also expressed constitutively in discreet locations where its inhibition drives gastrointestinal and cardiovascular/renal side effects. Constitutive COX-2 expression in the kidney regulates renal function and blood flow; however, the global relevance of the kidney versus other tissues to COX-2–dependent blood flow regulation is not known. Here, we used a microsphere deposition technique and pharmacological COX-2 inhibition to map the contribution of COX-2 to regional blood flow in mice and compared this to COX-2 expression patterns using luciferase reporter mice. Across all tissues studied, COX-2 inhibition altered blood flow predominantly in the kidney, with some effects also seen in the spleen, adipose, and testes. Of these sites, only the kidney displayed appreciable local COX-2 expression. As the main site where COX-2 regulates blood flow, we next analyzed the pathways involved in kidney vascular responses using a novel technique of video imaging small arteries in living tissue slices. We found that the protective effect of COX-2 on renal vascular function was associated with prostacyclin signaling through PPARβ/δ (peroxisome proliferator-activated receptor-β/δ). These data demonstrate the kidney as the principle site in the body where local COX-2 controls blood flow and identifies a previously unreported PPARβ/δ-mediated renal vasodilator pathway as the mechanism. These findings have direct relevance to the renal and cardiovascular side effects of drugs that inhibit COX-2, as well as the potential of the COX-2/prostacyclin/PPARβ/δ axis as a therapeutic target in renal disease.
Kirkby NS, Morris AP, Lytton J, et al., 2017, Genome-Wide Association Study Links Variants With Occurrence of Cardiovascular Events in People Taking the COX-2 Inhibitor Celecoxib: Identification of NCKX2 as a Novel Protective Pathway in Renal Vessels, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Mitchell JA, Shala F, Ahmetaj-Shala B, et al., 2017, Novel Tissue-specific Cyclooxygenase-1 Knockout Mice Demonstrate a Dominant Role for Endothelial Cyclooxygenase-1 in Prostacyclin Production, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Mitchell JA, Benson J, Shala F, et al., 2017, Vascular Prostanoids Paradoxically Amplify Vasoconstriction During Platelet Activation, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Kirkby NS, Jiao J, Herschman HR, et al., 2017, Production of High Levels of PGI-M in the Kidney and Bladder Explains the Renal Origin of Urinary Markers of Prostacyclin, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Tesfai A, MacCallum N, Kirkby NS, et al., 2017, Metabolomic profiling of amines in sepsis predicts changes in NOS canonical pathways, PLoS ONE, Vol: 12, ISSN: 1932-6203
RationaleNitric oxide synthase (NOS) is a biomarker/target in sepsis. NOS activity is driven by amino acids, which cycle to regulate the substrate L-arginine in parallel with cycles which regulate the endogenous inhibitors ADMA and L-NMMA. The relationship between amines and the consequence of plasma changes on iNOS activity in early sepsis is not known.ObjectiveOur objective was to apply a metabolomics approach to determine the influence of sepsis on a full array of amines and what consequence these changes may have on predicted iNOS activity.Methods and measurements34 amino acids were measured using ultra purification mass spectrometry in the plasma of septic patients (n = 38) taken at the time of diagnosis and 24–72 hours post diagnosis and of healthy volunteers (n = 21). L-arginine and methylarginines were measured using liquid-chromatography mass spectrometry and ELISA. A top down approach was also taken to examine the most changed metabolic pathways by Ingenuity Pathway Analysis. The iNOS supporting capacity of plasma was determined using a mouse macrophage cell-based bioassay.Main resultsOf all the amines measured 22, including L-arginine and ADMA, displayed significant differences in samples from patients with sepsis. The functional consequence of increased ADMA and decreased L-arginine in context of all cumulative metabolic changes in plasma resulted in reduced iNOS supporting activity associated with sepsis.ConclusionsIn early sepsis profound changes in amine levels were defined by dominant changes in the iNOS canonical pathway resulting in functionally meaningful changes in the ability of plasma to regulate iNOS activity ex vivo.
Mohamed NA, Davies RP, Lickiss PD, et al., 2017, Chemical and biological assessment of metal organic frameworks (MOFs) in pulmonary cells and in an acute in vivo model: relevance to pulmonary arterial hypertension therapy, Pulmonary Circulation, Vol: 7, Pages: 1-11, ISSN: 2045-8940
Pulmonary arterial hypertension (PAH) is a progressive and debilitating condition. Despite promoting vasodilation, current drugs have a therapeutic window within which they are limited by systemic side effects. Nanomedicine uses nanoparticles to improve drug delivery and/or reduce side effects. We hypothesize that this approach could be used to deliver PAH drugs avoiding the systemic circulation. Here we report the use of iron metal organic framework (MOF) MIL-89 and PEGylated MIL-89 (MIL-89 PEG) as suitable carriers for PAH drugs. We assessed their effects on viability and inflammatory responses in a wide range of lung cells including endothelial cells grown from blood of donors with/without PAH. Both MOFs conformed to the predicted structures with MIL-89 PEG being more stable at room temperature. At concentrations up to 10 or 30 µg/mL, toxicity was only seen in pulmonary artery smooth muscle cells where both MOFs reduced cell viability and CXCL8 release. In endothelial cells from both control donors and PAH patients, both preparations inhibited the release of CXCL8 and endothelin-1 and in macrophages inhibited inducible nitric oxide synthase activity. Finally, MIL-89 was well-tolerated and accumulated in the rat lungs when given in vivo. Thus, the prototypes MIL-89 and MIL-89 PEG with core capacity suitable to accommodate PAH drugs are relatively non-toxic and may have the added advantage of being anti-inflammatory and reducing the release of endothelin-1. These data are consistent with the idea that these materials may not only be useful as drug carriers in PAH but also offer some therapeutic benefit in their own right.
Crescente M, Armstrong PC, Chan MV, et al., 2017, PLATELET COX-1 KNOCKOUT MOUSE AS A MODEL OF THE EFFECTS OF ASPIRIN IN THE CARDIOVASCULAR SYSTEM, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: BMJ PUBLISHING GROUP, Pages: A108-A109, ISSN: 1355-6037
Parzych K, Zetterqvist A, Wright WR, et al., 2017, Differential role of the pannexin-1/ATP/P2X7 axis in IL-1β release by human monocytes, The FASEB Journal, Vol: 31, Pages: 2439-2445, ISSN: 0892-6638
IL-1βrelease is integral to the innateimmune system. The release of mature IL-1β depends on two regulated events; (i) the denovoinduction of pro-IL-1β, generally via NFκB-dependenttransduction pathwaysand (ii) the assembly and activation of the NLRP3 inflammasome. This latter step is reliant on active capase-1, pannexin-1 and P2X7receptor activation. Pathogen associated molecular patterns in Gram-positive and Gram-negative bacteria activate IL-1β release from immune cells via TLR2 and TLR4 receptors respectively. Here,we show that pro-IL-1β and mature IL-1β release from human monocytes is stimulated by the TLR2 agonists,Pam3CSK4 or FSL-1,and the TLR4 agonist,LPS, in the absence of additional ATP. TLR2 agonists required pannexin-1 and P2X7receptor activationto stimulate IL-1βrelease. By contrast, IL-1β release stimulated by the TLR4 agonist,LPS,is independent of both pannexin-1 and P2X7activation. In the absence of exogenous ATP,P2X7activation requires endogenous ATP release, which occurs in some cells via pannexin-1. In line with this,we found that LPS-stimulated human monocytes released relatively low levels of ATP,whereas cells stimulated with TLR2 agonists released high levels of ATP. These findings suggest that,in human monocytes, TLR2 and TLR4 signalling bothinduce pro-IL-1β expression,but the mechanism by which they activate caspase-1 diverges at the level of the pannexin-1/ATP/P2X7axis.
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