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Normal Saline solutions cause endothelial dysfunction through loss of membrane integrity, ATP release, and inflammatory responses mediated by P2X7R/p38 MAPK/MK2 signaling pathways.
Cheung-Flynn J, Alvis BD, Hocking KM, Guth CM, Luo W, McCallister R, Chadalavada K, Polcz M, Komalavilas P, Brophy CM
(2019) PLoS One 14: e0220893
MeSH Terms: Adenosine Triphosphate, Animals, Aorta, Cell Membrane, Endothelial Cells, Humans, Inflammation, Intracellular Signaling Peptides and Proteins, Phosphorylation, Protein-Serine-Threonine Kinases, Rats, Receptors, Purinergic P2X7, Saline Solution, Saphenous Vein, Signal Transduction, Swine, p38 Mitogen-Activated Protein Kinases
Show Abstract · Added March 3, 2020
Resuscitation with 0.9% Normal Saline (NS), a non-buffered acidic solution, leads to increased morbidity and mortality in the critically ill. The goal of this study was to determine the molecular mechanisms of endothelial injury after exposure to NS. The hypothesis of this investigation is that exposure of endothelium to NS would lead to loss of cell membrane integrity, resulting in release of ATP, activation of the purinergic receptor (P2X7R), and subsequent activation of stress activated signaling pathways and inflammation. Human saphenous vein endothelial cells (HSVEC) incubated in NS, but not buffered electrolyte solution (Plasma-Lyte, PL), exhibited abnormal morphology and increased release of lactate dehydrogenase (LDH), adenosine triphosphate (ATP), and decreased transendothelial resistance (TEER), suggesting loss of membrane integrity. Incubation of intact rat aorta (RA) or human saphenous vein in NS but not PL led to impaired endothelial-dependent relaxation which was ameliorated by apyrase (hydrolyzes ATP) or SB203580 (p38 MAPK inhibitor). Exposure of HSVEC to NS but not PL led to activation of p38 MAPK and its downstream substrate, MAPKAP kinase 2 (MK2). Treatment of HSVEC with exogenous ATP led to interleukin 1β (IL-1β) release and increased vascular cell adhesion molecule (VCAM) expression. Treatment of RA with IL-1β led to impaired endothelial relaxation. IL-1β treatment of HSVEC led to increases in p38 MAPK and MK2 phosphorylation, and increased levels of arginase II. Incubation of porcine saphenous vein (PSV) in PL with pH adjusted to 6.0 or less also led to impaired endothelial function, suggesting that the acidic nature of NS is what contributes to endothelial dysfunction. Volume overload resuscitation in a porcine model after hemorrhage with NS, but not PL, led to acidosis and impaired endothelial function. These data suggest that endothelial dysfunction caused by exposure to acidic, non-buffered NS is associated with loss of membrane integrity, release of ATP, and is modulated by P2X7R-mediated inflammatory responses.
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17 MeSH Terms
Aberrant FGFR signaling mediates resistance to CDK4/6 inhibitors in ER+ breast cancer.
Formisano L, Lu Y, Servetto A, Hanker AB, Jansen VM, Bauer JA, Sudhan DR, Guerrero-Zotano AL, Croessmann S, Guo Y, Ericsson PG, Lee KM, Nixon MJ, Schwarz LJ, Sanders ME, Dugger TC, Cruz MR, Behdad A, Cristofanilli M, Bardia A, O'Shaughnessy J, Nagy RJ, Lanman RB, Solovieff N, He W, Miller M, Su F, Shyr Y, Mayer IA, Balko JM, Arteaga CL
(2019) Nat Commun 10: 1373
MeSH Terms: Aminopyridines, Animals, Antineoplastic Agents, Hormonal, Antineoplastic Combined Chemotherapy Protocols, Breast Neoplasms, Circulating Tumor DNA, Cyclin D1, Cyclin-Dependent Kinase 4, Cyclin-Dependent Kinase 6, Drug Resistance, Neoplasm, Female, Fulvestrant, High-Throughput Nucleotide Sequencing, Humans, MCF-7 Cells, Mice, Mutation, Naphthalenes, Piperazines, Progression-Free Survival, Proportional Hazards Models, Protein Kinase Inhibitors, Purines, Pyrazoles, Pyridines, Quinolines, Quinoxalines, Receptor, Fibroblast Growth Factor, Type 1, Receptor, Fibroblast Growth Factor, Type 2, Receptors, Estrogen, Signal Transduction, Xenograft Model Antitumor Assays
Show Abstract · Added April 2, 2019
Using an ORF kinome screen in MCF-7 cells treated with the CDK4/6 inhibitor ribociclib plus fulvestrant, we identified FGFR1 as a mechanism of drug resistance. FGFR1-amplified/ER+ breast cancer cells and MCF-7 cells transduced with FGFR1 were resistant to fulvestrant ± ribociclib or palbociclib. This resistance was abrogated by treatment with the FGFR tyrosine kinase inhibitor (TKI) lucitanib. Addition of the FGFR TKI erdafitinib to palbociclib/fulvestrant induced complete responses of FGFR1-amplified/ER+ patient-derived-xenografts. Next generation sequencing of circulating tumor DNA (ctDNA) in 34 patients after progression on CDK4/6 inhibitors identified FGFR1/2 amplification or activating mutations in 14/34 (41%) post-progression specimens. Finally, ctDNA from patients enrolled in MONALEESA-2, the registration trial of ribociclib, showed that patients with FGFR1 amplification exhibited a shorter progression-free survival compared to patients with wild type FGFR1. Thus, we propose breast cancers with FGFR pathway alterations should be considered for trials using combinations of ER, CDK4/6 and FGFR antagonists.
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32 MeSH Terms
Genome-wide and candidate gene approaches of clopidogrel efficacy using pharmacodynamic and clinical end points-Rationale and design of the International Clopidogrel Pharmacogenomics Consortium (ICPC).
Bergmeijer TO, Reny JL, Pakyz RE, Gong L, Lewis JP, Kim EY, Aradi D, Fernandez-Cadenas I, Horenstein RB, Lee MTM, Whaley RM, Montaner J, Gensini GF, Cleator JH, Chang K, Holmvang L, Hochholzer W, Roden DM, Winter S, Altman RB, Alexopoulos D, Kim HS, Déry JP, Gawaz M, Bliden K, Valgimigli M, Marcucci R, Campo G, Schaeffeler E, Dridi NP, Wen MS, Shin JG, Simon T, Fontana P, Giusti B, Geisler T, Kubo M, Trenk D, Siller-Matula JM, Ten Berg JM, Gurbel PA, Hulot JS, Mitchell BD, Schwab M, Ritchie MD, Klein TE, Shuldiner AR, ICPC Investigators
(2018) Am Heart J 198: 152-159
MeSH Terms: Acute Coronary Syndrome, Aged, Clopidogrel, Female, Genetic Association Studies, Genome-Wide Association Study, Humans, Internationality, Male, Middle Aged, Molecular Targeted Therapy, Pharmacogenetics, Prognosis, Receptors, Purinergic P2Y12, Risk Assessment, Survival Rate, Treatment Outcome
Show Abstract · Added March 24, 2020
RATIONALE - The P2Y receptor inhibitor clopidogrel is widely used in patients with acute coronary syndrome, percutaneous coronary intervention, or ischemic stroke. Platelet inhibition by clopidogrel shows wide interpatient variability, and high on-treatment platelet reactivity is a risk factor for atherothrombotic events, particularly in high-risk populations. CYP2C19 polymorphism plays an important role in this variability, but heritability estimates suggest that additional genetic variants remain unidentified. The aim of the International Clopidogrel Pharmacogenomics Consortium (ICPC) is to identify genetic determinants of clopidogrel pharmacodynamics and clinical response.
STUDY DESIGN - Based on the data published on www.clinicaltrials.gov, clopidogrel intervention studies containing genetic and platelet function data were identified for participation. Lead investigators were invited to share DNA samples, platelet function test results, patient characteristics, and cardiovascular outcomes to perform candidate gene and genome-wide studies.
RESULTS - In total, 17 study sites from 13 countries participate in the ICPC, contributing individual patient data from 8,829 patients. Available adenosine diphosphate-stimulated platelet function tests included vasodilator-stimulated phosphoprotein assay, light transmittance aggregometry, and the VerifyNow P2Y assay. A proof-of-principle analysis based on genotype data provided by each group showed a strong and consistent association between CYP2C19*2 and platelet reactivity (P value=5.1 × 10).
CONCLUSION - The ICPC aims to identify new loci influencing clopidogrel efficacy by using state-of-the-art genetic approaches in a large cohort of clopidogrel-treated patients to better understand the genetic basis of on-treatment response variability.
Copyright © 2017 Elsevier Inc. All rights reserved.
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Mechanosensitive Ion Channels: TRPV4 and P2X7 in Disseminating Cancer Cells.
Hope JM, Greenlee JD, King MR
(2018) Cancer J 24: 84-92
MeSH Terms: Animals, Cell Movement, Humans, Mechanotransduction, Cellular, Neoplasms, Receptors, Purinergic P2X7, TRPV Cation Channels
Show Abstract · Added April 15, 2019
Cancer metastasis is the second leading cause of death in the United States. Despite its morbidity, metastasis is an inefficient process that few cells can survive. However, cancer cells can overcome these metastatic barriers via cellular responses to microenvironmental cues, such as through mechanotransduction. This review focuses on the mechanosensitive ion channels TRPV4 and P2X7, and their roles in metastasis, as both channels have been shown to significantly affect tumor cell dissemination. Upon activation, these channels help form tumor neovasculature, promote transendothelial migration, and increase cell motility. Conversely, they have also been linked to forms of cancer cell death dependent upon levels of activation, implying the complex functionality of mechanosensitive ion channels. Understanding the roles of TRPV4, P2X7 and other mechanosensitive ion channels in these processes may reveal new possible drug targets that modify channel function to reduce a tumor's metastatic potential.
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Oxidative stress increases M1dG, a major peroxidation-derived DNA adduct, in mitochondrial DNA.
Wauchope OR, Mitchener MM, Beavers WN, Galligan JJ, Camarillo JM, Sanders WD, Kingsley PJ, Shim HN, Blackwell T, Luong T, deCaestecker M, Fessel JP, Marnett LJ
(2018) Nucleic Acids Res 46: 3458-3467
MeSH Terms: Animals, Bone Morphogenetic Protein Receptors, Type II, DNA Adducts, DNA, Mitochondrial, Electron Transport, Endothelial Cells, Gene Expression Regulation, Humans, Hypertension, Pulmonary, Lipid Peroxidation, Mice, Mice, Transgenic, Mitochondria, Mutagenesis, Oxidants, Oxidative Stress, Purine Nucleosides, Reactive Oxygen Species, Superoxides
Show Abstract · Added March 14, 2018
Reactive oxygen species (ROS) are formed in mitochondria during electron transport and energy generation. Elevated levels of ROS lead to increased amounts of mitochondrial DNA (mtDNA) damage. We report that levels of M1dG, a major endogenous peroxidation-derived DNA adduct, are 50-100-fold higher in mtDNA than in nuclear DNA in several different human cell lines. Treatment of cells with agents that either increase or decrease mitochondrial superoxide levels leads to increased or decreased levels of M1dG in mtDNA, respectively. Sequence analysis of adducted mtDNA suggests that M1dG residues are randomly distributed throughout the mitochondrial genome. Basal levels of M1dG in mtDNA from pulmonary microvascular endothelial cells (PMVECs) from transgenic bone morphogenetic protein receptor 2 mutant mice (BMPR2R899X) (four adducts per 106 dG) are twice as high as adduct levels in wild-type cells. A similar increase was observed in mtDNA from heterozygous null (BMPR2+/-) compared to wild-type PMVECs. Pulmonary arterial hypertension is observed in the presence of BMPR2 signaling disruptions, which are also associated with mitochondrial dysfunction and oxidant injury to endothelial tissue. Persistence of M1dG adducts in mtDNA could have implications for mutagenesis and mitochondrial gene expression, thereby contributing to the role of mitochondrial dysfunction in diseases.
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19 MeSH Terms
Vascular surgical stretch injury leads to activation of P2X7 receptors and impaired endothelial function.
Komalavilas P, Luo W, Guth CM, Jolayemi O, Bartelson RI, Cheung-Flynn J, Brophy CM
(2017) PLoS One 12: e0188069
MeSH Terms: Animals, Endothelium, Vascular, Female, Nitric Oxide, Phosphorylation, Rats, Rats, Sprague-Dawley, Receptors, Purinergic P2X7, Vascular Surgical Procedures, p38 Mitogen-Activated Protein Kinases
Show Abstract · Added May 22, 2018
A viable vascular endothelial layer prevents vasomotor dysfunction, thrombosis, inflammation, and intimal hyperplasia. Injury to the endothelium occurs during harvest and "back table" preparation of human saphenous vein prior to implantation as an arterial bypass conduit. A subfailure overstretch model of rat aorta was used to show that subfailure stretch injury of vascular tissue leads to impaired endothelial-dependent relaxation. Stretch-induced impaired relaxation was mitigated by treatment with purinergic P2X7 receptor (P2X7R) inhibitors, brilliant blue FCF (FCF) and A740003, or apyrase, an enzyme that catalyzes the hydrolysis of ATP. Alternatively, treatment of rat aorta with exogenous ATP or 2'(3')-O-(4-Benzoyl benzoyl)-ATP (BzATP) also impaired endothelial-dependent relaxation. Treatment of human saphenous vein endothelial cells (HSVEC) with exogenous ATP led to reduced nitric oxide production which was associated with increased phosphorylation of the stress activated protein kinase, p38 MAPK. ATP- stimulated p38 MAPK phosphorylation of HSVEC was inhibited by FCF and SB203580. Moreover, ATP inhibition of nitric oxide production in HSVEC was prevented by FCF, SB203580, L-arginine supplementation and arginase inhibition. Finally, L-arginine supplementation and arginase inhibition restored endothelial dependent relaxation after stretch injury of rat aorta. These results suggest that vascular stretch injury leads to ATP release, activation of P2X7R and p38 MAPK resulting in endothelial dysfunction due to arginase activation. Endothelial function can be restored in both ATP treated HSVEC and intact stretch injured rat aorta by P2X7 receptor inhibition with FCF or L-arginine supplementation, implicating straightforward therapeutic options for treatment of surgical vascular injury.
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P2X7R antagonism after subfailure overstretch injury of blood vessels reverses vasomotor dysfunction and prevents apoptosis.
Luo W, Feldman D, McCallister R, Brophy C, Cheung-Flynn J
(2017) Purinergic Signal 13: 579-590
MeSH Terms: Animals, Aorta, Apoptosis, Coronary Artery Bypass, Female, Humans, Male, Purinergic P2X Receptor Antagonists, Rats, Rats, Sprague-Dawley, Receptors, Purinergic P2X7, Saphenous Vein, Specimen Handling
Show Abstract · Added May 22, 2018
Human saphenous vein (HSV) is harvested and prepared prior to implantation as an arterial bypass graft. Injury and the response to injury from surgical harvest and preparation trigger cascades of molecular events and contribute to graft remodeling and intimal hyperplasia. Apoptosis is an early response after implantation that contributes the development of neointimal lesions. Here, we showed that surgical harvest and preparation of HSV leads to vasomotor dysfunction, increased apoptosis and downregulation of the phosphorylation of the anti-apoptotic protein, Niban. A model of subfailure overstretch injury in rat aorta (RA) was used to demonstrate impaired vasomotor function, increased extracellular ATP (eATP) release, and increased apoptosis following pathological vascular injury. The subfailure overstretch injury was associated with activation of p38 MAPK stress pathway and decreases in the phosphorylation of the anti-apoptotic protein Niban. Treatment of RA after overstretch injury with antagonists to purinergic P2X7 receptor (P2X7R) antagonists or P2X7R/pannexin (PanX1) complex, but not PanX1 alone, restored vasomotor function. Inhibitors to P2X7R and PanX1 reduced stretch-induced eATP release. P2X7R/PanX1 antagonism led to decrease in p38 MAPK phosphorylation, restoration of Niban phosphorylation and increases in the phosphorylation of the anti-apoptotic protein Akt in RA and reduced TNFα-stimulated caspase 3/7 activity in cultured rat vascular smooth muscle cells. In conclusion, inhibition of P2X7R after overstretch injury restored vasomotor function and inhibited apoptosis. Treatment with P2X7R/PanX1 complex inhibitors after harvest and preparation injury of blood vessels used for bypass conduits may prevent the subsequent response to injury that lead to apoptosis and represents a novel therapeutic approach to prevent graft failure.
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13 MeSH Terms
Adenosine triphosphate as a molecular mediator of the vascular response to injury.
Guth CM, Luo W, Jolayemi O, Chadalavada KS, Komalavilas P, Cheung-Flynn J, Brophy CM
(2017) J Surg Res 216: 80-86
MeSH Terms: Adenosine Triphosphate, Animals, Aorta, Abdominal, Biomarkers, Biomechanical Phenomena, Blotting, Western, Female, Muscle Contraction, Rats, Rats, Sprague-Dawley, Receptors, Purinergic P2X7, Stress, Mechanical, Vascular System Injuries, p38 Mitogen-Activated Protein Kinases
Show Abstract · Added May 22, 2018
BACKGROUND - Human saphenous veins used for arterial bypass undergo stretch injury at the time of harvest and preimplant preparation. Vascular injury promotes intimal hyperplasia, the leading cause of graft failure, but the molecular events leading to this response are largely unknown. This study investigated adenosine triphosphate (ATP) as a potential molecular mediator in the vascular response to stretch injury, and the downstream effects of the purinergic receptor, P2X7R, and p38 MAPK activation.
MATERIALS AND METHODS - A subfailure stretch rat aorta model was used to determine the effect of stretch injury on release of ATP and vasomotor responses. Stretch-injured tissues were treated with apyrase, the P2X7R antagonist, A438079, or the p38 MAPK inhibitor, SB203580, and subsequent contractile forces were measured using a muscle bath. An exogenous ATP (eATP) injury model was developed and the experiment repeated. Change in p38 MAPK phosphorylation after stretch and eATP tissue injury was determined using Western blotting. Noninjured tissue was incubated in the p38 MAPK activator, anisomycin, and subsequent contractile function and p38 MAPK phosphorylation were analyzed.
RESULTS - Stretch injury was associated with release of ATP. Contractile function was decreased in tissue subjected to subfailure stretch, eATP, and anisomycin. Contractile function was restored by apyrase, P2X7R antagonism, and p38-MAPK inhibition. Stretch, eATP, and anisomycin-injured tissue demonstrated increased phosphorylation of p38 MAPK.
CONCLUSIONS - Taken together, these data suggest that the vascular response to stretch injury is associated with release of ATP and activation of the P2X7R/P38 MAPK pathway, resulting in contractile dysfunction. Modulation of this pathway in vein grafts after harvest and before implantation may reduce the vascular response to injury.
Copyright © 2017 Elsevier Inc. All rights reserved.
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Prostaglandin E glyceryl ester is an endogenous agonist of the nucleotide receptor P2Y.
Brüser A, Zimmermann A, Crews BC, Sliwoski G, Meiler J, König GM, Kostenis E, Lede V, Marnett LJ, Schöneberg T
(2017) Sci Rep 7: 2380
MeSH Terms: Animals, Binding Sites, Cell Line, Tumor, Cyclooxygenase 2, Dinoprostone, HEK293 Cells, High-Throughput Nucleotide Sequencing, High-Throughput Screening Assays, Humans, Kinetics, Ligands, Mice, Molecular Docking Simulation, Protein Binding, Protein Conformation, alpha-Helical, Protein Conformation, beta-Strand, Protein Interaction Domains and Motifs, Purinergic Agonists, RAW 264.7 Cells, Receptors, Purinergic P2, Substrate Specificity, Thermodynamics, Transcriptome
Show Abstract · Added March 17, 2018
Cyclooxygenase-2 catalyses the biosynthesis of prostaglandins from arachidonic acid but also the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. Previous studies identified PG-Gs as signalling molecules involved in inflammation. Thus, the glyceryl ester of prostaglandin E, PGE-G, mobilizes Ca and activates protein kinase C and ERK, suggesting the involvement of a G protein-coupled receptor (GPCR). To identify the endogenous receptor for PGE-G, we performed a subtractive screening approach where mRNA from PGE-G response-positive and -negative cell lines was subjected to transcriptome-wide RNA sequencing analysis. We found several GPCRs that are only expressed in the PGE-G responder cell lines. Using a set of functional readouts in heterologous and endogenous expression systems, we identified the UDP receptor P2Y as the specific target of PGE-G. We show that PGE-G and UDP are both agonists at P2Y, but they activate the receptor with extremely different EC values of ~1 pM and ~50 nM, respectively. The identification of the PGE-G/P2Y pair uncovers the signalling mode of PG-Gs as previously under-appreciated products of cyclooxygenase-2.
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23 MeSH Terms
Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli.
Shaffer CL, Zhang EW, Dudley AG, Dixon BREA, Guckes KR, Breland EJ, Floyd KA, Casella DP, Algood HMS, Clayton DB, Hadjifrangiskou M
(2017) Infect Immun 85:
MeSH Terms: Animals, Cytoplasm, Epithelial Cells, Escherichia coli Infections, Escherichia coli Proteins, Female, Humans, Mice, Mice, Inbred C3H, Purines, Urinary Bladder, Urinary Tract Infections, Uropathogenic Escherichia coli, Virulence
Show Abstract · Added November 3, 2016
The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement.
Copyright © 2016 American Society for Microbiology.
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14 MeSH Terms