Endogenous adenosine produced during hypoxia attenuates neutrophil accumulation: coordination by extracellular nucleotide metabolism

Abstract Hypoxia is a well-documented inflammatory stimulus and results in tissue polymorphonuclear leukocyte (PMN) accumulation. Likewise, increased tissue adenosine levels are commonly associated with hypoxia, and given the anti-inflammatory properties of adenosine, we hypothesized that adenosine production via adenine nucleotide metabolism at the vascular surface triggers an endogenous anti-inflammatory response during hypoxia. Initial in vitro studies indicated that endogenously generated adenosine, through activation of PMN adenosine A2A and A2B receptors, functions as an antiadhesive signal for PMN binding to microvascular endothelia. Intravascular nucleotides released by inflammatory cells undergo phosphohydrolysis via hypoxia-induced CD39 ectoapyrase (CD39 converts adenosine triphosphate/adenosine diphosphate [ATP/ADP] to adenosine monophosphate [AMP]) and CD73 ecto-5′-nucleotidase (CD73 converts AMP to adenosine). Extensions of our in vitro findings using cd39- and cd73-null animals revealed that extracellular adenosine produced through adenine nucleotide metabolism during hypoxia is a potent anti-inflammatory signal for PMNs in vivo. These findings identify CD39 and CD73 as critical control points for endogenous adenosine generation and implicate this pathway as an innate mechanism to attenuate excessive tissue PMN accumulation. (Blood. 2004;104:3986-3992)

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The Murine Misty Mutation: Phenotypic Effects on Melanocytes, Platelets and Brown Fat

Genetics ◽

10.1093/genetics/148.1.381 ◽

1998 ◽

Vol 148 (1) ◽

pp. 381-390

Author(s):

Elena V Sviderskaya ◽

Edward K Novak ◽

Richard T Swank ◽

Dorothy C Bennett

Keyword(s):

Coat Color ◽

Adenine Nucleotide ◽

Primary Cultures ◽

Cell Types ◽

Nucleotide Metabolism ◽

Brown Fat ◽

Melanocyte Stimulating Hormone ◽

Prolonged Bleeding Time ◽

Adenine Nucleotide Metabolism

Abstract Although the recessive murine mutation misty (m) is well known, its phenotype has never been reported beyond brief descriptions of a dilution of coat color and white spotting of the belly and extremities, suggesting a developmental mutation. A report in abstract has also suggested effects on white fat and body weight. Here, we report effects of the homozygous misty mutation on an unusual combination of three cell types: melanocytes, platelets, and brown fat. Brown fat appeared to be completely absent from all expected locations in neonatal m/m mice. A prolonged bleeding time was observed; platelet count and platelet serotonin and ATP levels were normal, but the level of ADP in m/m platelets was low. Primary cultures and immortal lines of melanocytes from m/m mice showed several abnormalities. There was a marked deficiency in net proliferation, suggesting that the color dilution and spotting in vivo may result from reduced numbers of melanocytes and their precursors. m/m melanocytes were also hyperdendritic in morphology, overproduced melanin, and had deficient responses to the cAMP agonists cholera toxin and melanocyte-stimulating hormone, which normally promote melanin production. The misty gene product may be involved in adenine nucleotide metabolism or signaling.

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Studies on the Platelet Defect in Alcoholism

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647883 ◽

1975 ◽

Vol 33 (02) ◽

pp. 310-327 ◽

Cited By ~ 7

Author(s):

Dale H Cowan ◽

Richard C Graham

Keyword(s):

Platelet Function ◽

Adenine Nucleotide ◽

Specific Radioactivity ◽

Protein Composition ◽

Nucleotide Metabolism ◽

Supernatant Fraction ◽

Release Mechanism ◽

Adenine Nucleotide Metabolism ◽

Thrombocytopenic Patient

SummaryPlatelet ultrastructure, protein composition, and adenine nucleotide metabolism were studied in patients ingesting ethanol to elucidate the mechanism of ethanol-induced changes in platelet function and survival. Serial measurements were made in 2 patients who maintained blood ethanol levels in excess of 300 mg/100 ml for 3 to 4 weeks. No major changes in structure or metabolism were detected in platelets from the patient whose platelet counts remained stable during the ingestion period. By contrast, the development of thrombocytopenia in the other patient was associated with significantly reduced intracellular ADP, increased ATP/ADP ratio, decreased release of ADP, increased specific radioactivity of intracellular ATP and ADP, and increased formation of hypoxanthine. Additionally, platelets from this patient varied markedly in size, contained giant granules, and possessed a poorly defined micro-tubular system. After stimulation with ADP or collagen, centripetal granule migration was retarded, and the aggregates formed were small and loose. Several large proteins were absent from the supernatant fraction of sonicated platelets from the thrombocytopenic patient. Exposure of normal platelets to ethanol in vitro resulted in no detectable change in platelet ultrastructure. The data indicate that the ethanol-related abnormalities of platelet function are due in part to subnormal amounts of intracellular ADP and a deficit in the storage pool of ADP. Additionally, the results suggest that impairment in the release mechanism to the observed defect in the release reaction.

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Cyclic nucleotide metabolism and vasodilation in canine mesenteric artery

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1977.232.2.h191 ◽

1977 ◽

Vol 232 (2) ◽

pp. H191-H196

Author(s):

D. Mailman ◽

W. Pawilk ◽

A. P. Shepherd ◽

L. L. Tague ◽

E. D. Jacobson

Keyword(s):

Adenosine Monophosphate ◽

Peak Effect ◽

Nucleotide Metabolism ◽

Mesenteric Arteries ◽

Tissue Uptake ◽

Dibutyryl Camp ◽

Intracellular Metabolism ◽

Layer Chromatography

The uptake and extracellular and intracellular metabolism of radioisotopically labeled cyclic 3',5'-adenosine monophosphate (cAMP) and dibutyryl cAMP (DBcAMP) was determined in canine mesenteric arteries incubated in vitro. Intracellular tissue uptake was measured by radioisotope counting and labeled metabolites separated by thin-layer chromatography. Extracellularly, cAMP was extensively metabolized to AMP, adenosine, and Pi. DBcAMP was metabolized to monobutyryl cAMP (MBcAMP) intracellularly. Vasodilation of the mesenteric circulation in vivo was produced by cAMP, its metabolites and DBcAMP. DBcAMP caused greater vasodilation than cAMP but had a response time to its peak effect of 12 min versus 90 s for cAMP. The vasodilator properties of cAMP and DBcAMP were related to their metabolism. It was concluded that the vasodilation caused by cAMP was due to cAMP metabolites produced by extracellular metabolism.

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Aminophylline and progesterone prevent inflammation-induced preterm parturition in the mouse†

Biology of Reproduction ◽

10.1093/biolre/ioz112 ◽

2019 ◽

Vol 101 (4) ◽

pp. 813-822 ◽

Cited By ~ 4

Author(s):

Bronwen R Herbert ◽

Danijela Markovic ◽

Ektoras Georgiou ◽

Pei F Lai ◽

Natasha Singh ◽

...

Keyword(s):

Ex Vivo ◽

Phosphodiesterase Inhibitor ◽

Adenosine Monophosphate ◽

Cytokine Gene Expression ◽

Intracellular Camp ◽

Myometrial Cells ◽

Anti Inflammatory ◽

Camp Levels

Abstract Although progesterone (P4) supplementation is the most widely used therapy for the prevention of preterm labor (PTL), reports of its clinical efficacy have been conflicting. We have previously shown that the anti-inflammatory effects of P4 can be enhanced by increasing intracellular cyclic adenosine monophosphate (cAMP) levels in primary human myometrial cells. Here, we have examined whether adding aminophylline (Am), a non-specific phosphodiesterase inhibitor that increases intracellular cAMP levels, to P4 might improve its efficacy using in vivo and in vitro models of PTL. In a mouse model of lipopolysaccharide (LPS)-induced PTL, we found that the combination of P4 and Am delayed the onset of LPS-induced PTL, while the same dose of P4 and Am alone had no effect. Pup survival was not improved by either agent alone or in combination. Myometrial prolabor and inflammatory cytokine gene expression was reduced, but the reduction was similar in P4 and P4/Am treated mice. There was no effect of the combination of P4 and Am on an ex vivo assessment of myometrial contractility. In human myometrial cells and myometrial tissue explants, we found that the combination had marked anti-inflammatory effects, reducing cytokine and COX-2 mRNA and protein levels to a greater extent than either agent alone. These data suggest that the combination of P4 and Am has a more potent anti-inflammatory effect than either agent alone and may be an effective combination in women at high-risk of PTL.

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Correlation between in vitro Cyclic Adenosine Monophosphate Phosphodiesterase Inhibition and in vivo Anti-Inflammatory Effect

Skin Pharmacology and Physiology ◽

10.1159/000029912 ◽

2000 ◽

Vol 13 (2) ◽

pp. 86-92 ◽

Cited By ~ 7

Author(s):

Earl Goyarts ◽

Thomas Mammone ◽

Neelam Muizzuddin ◽

Ken Marenus ◽

Daniel Maes

Keyword(s):

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Phosphodiesterase Inhibition ◽

Anti Inflammatory ◽

Inflammatory Effect

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Participation of the adenosine salvage pathway and cyclic AMP modulation in oocyte energy metabolism

Scientific Reports ◽

10.1038/s41598-019-54693-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Dulama Richani ◽

Cathy F. Lavea ◽

Raji Kanakkaparambil ◽

Angelique H. Riepsamen ◽

Michael J. Bertoldo ◽

...

Keyword(s):

Cyclic Amp ◽

Adenine Nucleotide ◽

Cumulus Cells ◽

Nucleotide Metabolism ◽

Salvage Pathway ◽

Developmental Potential ◽

Mouse Oocytes ◽

Junctional Communication

AbstractA follicular spike in cyclic AMP (cAMP) and its subsequent degradation to AMP promotes oocyte maturation and ovulation. In vitro matured (IVM) oocytes do not receive the cAMP increase that occurs in vivo, and artificial elevation of cAMP in IVM cumulus-oocyte complexes improves oocyte developmental potential. This study examined whether mouse oocytes can use the cAMP degradation product AMP to generate ATP via the adenosine salvage pathway, and examined whether pharmacological elevation of cAMP in IVM cumulus-oocyte complexes alters ATP levels. Oocytes cultured with isotopic 13C5-AMP dose-dependently produced 13C5-ATP, however total cellular ATP remained constant. Pharmacological elevation of cAMP using forskolin and IBMX prior to IVM decreased oocyte ATP and ATP:ADP ratio, and promoted activity of the energy regulator AMPK. Conversely, cumulus cells exhibited higher ATP and no change in AMPK. Culture of oocytes without their cumulus cells or inhibition of their gap-junctional communication yielded lower oocyte 13C5-ATP, indicating that cumulus cells facilitate ATP production via the adenosine salvage pathway. In conclusion, this study demonstrates that mouse oocytes can generate ATP from AMP via the adenosine salvage pathway, and cAMP elevation alters adenine nucleotide metabolism and may provide AMP for energy production via the adenosine salvage pathway during the energetically demanding process of meiotic maturation.

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Phospholipid and adenine nucleotide metabolism in muscle after burn injury

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1985.249.5.r603 ◽

1985 ◽

Vol 249 (5) ◽

pp. R603-R610

Author(s):

J. Turinsky ◽

I. H. Chaudry

Keyword(s):

Burn Injury ◽

Adenine Nucleotide ◽

Adenine Nucleotides ◽

Energy Charge ◽

Nucleotide Metabolism ◽

Adenylate Energy Charge ◽

Adenine Nucleotide Metabolism ◽

Limb Muscles ◽

32P Incorporation

The role of phospholipid and adenine nucleotide metabolism in postburn unresponsiveness of muscle to insulin was examined. A single hindlimb scald in the rat was produced, and 3 days later soleus muscles were incubated in vitro with and without insulin. Under basal conditions muscles from the burned limbs had normal contents of phosphatidylcholine and phosphatidylinositol but decreased diphosphatidylglycerol (-39%) and phosphatidylethanolamine (-24%) and increased sphingomyelin (+62%), lysophosphatidylcholine (+68%), and phosphatidylserine (+13%) compared with the contralateral unburned limb. Such muscle also incorporated 107-396% more [32P]phosphate into all measured phospholipids, except for diphosphatidylglycerol. The presence of insulin had no effect on either the mass of phospholipids or 32P incorporation in any muscle. The burned limb muscles (frozen in situ) also exhibited lower levels of ATP (-25%) and total adenine nucleotides (-24%) than uninjured muscle but normal adenylate energy charge. The burned limb muscles had lower adenosine (-37%), but inosine and hypoxanthine were 82 and 39% higher, respectively. These data suggest recovery of muscle from local thermal injury is associated with alterations in mass, and possibly also turnover, of tissue phospholipids, the measured phospholipids do not mediate the postreceptor action of insulin in normal muscle, energy charge of the recovering injured muscle is restored before ATP level at the time when this muscle is unresponsive to insulin stimulation.

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