Targeted deletion of A2A adenosine receptors attenuates the protective effects of myocardial postconditioning

2007 ◽  
Vol 293 (4) ◽  
pp. H2523-H2529 ◽  
Author(s):  
R. Ray Morrison ◽  
Xing Lin Tan ◽  
Catherine Ledent ◽  
S. Jamal Mustafa ◽  
Polly A. Hofmann

Endogenous adenosine is an important ligand trigger for the cardioprotective effects of postconditioning (POC), yet it is unclear which adenosine receptor subtype is primarily responsible. To evaluate the role of A2A adenosine receptors in POC-induced protection, global ischemia-reperfusion was performed with and without POC in isolated wild-type (WT) and A2A adenosine receptor knockout (A2AKO) mouse hearts. Injury was measured in terms of postischemic functional recovery and release of cardiac troponin I (cTnI). Activation of protective signaling with POC was assessed by Akt and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation. In WT hearts, POC improved recovery of postischemic developed pressure in early (81.6 ± 6.4% of preischemic baseline vs. 37.5 ± 5.6% for non-POC WT at 1 min) and late (62.2 ± 4.2% of baseline vs. 45.5 ± 5.3% for non-POC WT at 30 min) reperfusion, reduced cTnI release by 37%, and doubled the phosphorylation of both Akt and ERK1/2. These beneficial effects of POC were blocked by treatment with the selective A2A adenosine receptor antagonist ZM-241385 during reperfusion. Postischemic functional recovery, cTnI release, and phosphorylation of Akt and ERK1/2 were not different between non-POC WT and A2AKO hearts. In A2AKO hearts, POC did not improve functional recovery, reduce cTnI release, nor increase phosphorylation of Akt or ERK1/2. Thus the protective effects of POC are attenuated by both selective A2A receptor antagonism and targeted deletion of the gene encoding A2A adenosine receptors. These observations support the conclusion that endogenous activation of A2A adenosine receptors is an essential trigger leading to the protective effects of POC in isolated murine hearts.

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Xinglin Tan ◽  
Stephen L Tilley ◽  
Thomas Krahn ◽  
Bunyen Teng ◽  
S. J Mustafa ◽  
...  

Endogenous adenosine is an important ligand trigger for the cardioprotective effects of postconditioning (PostCon). To assess the hypothesis that A 2B adenosine receptor (A 2B AR) activation contributes to PostCon-induced protection, global ischemia-reperfusion was performed with and without PostCon or the selective A 2B agonist, BAY 60 – 6583 (BAY), in isolated wild-type (WT) and A 2B AR knockout (A 2B KO) mouse hearts. In WT hearts, PostCon improved post-ischemic recovery of left ventricular developed pressure (LVDP) to 63.3±1.6 % of pre-ischemic baseline vs. 49.9±1.6 % in non-PostCon controls (CTL), lowered end diastolic pressure (EDP) to 15.8±1.5 mmHg vs. 27.9±1.6 mmHg in CTL, and reduced coronary efflux of cardiac troponin I (cTnI) to 2507±359 ng/g heart weight vs. 4693±343 ng/g in CTL (n=12 both groups, p <0.05 each comparison). Treatment with BAY in the first two min of reperfusion mimicked beneficial effects of PostCon in WT hearts (LVDP: 64.7±2.0 % baseline, EDP: 16.2±2.0 mmHg, cTnI: 3311±366; n=13, not significant compared to respective PostCon values). Real-time PCR confirmed absence of A 2B AR in A 2B KO hearts and demonstrated no changes in expression of other adenosine receptor subtypes compared with WT hearts. In A 2B KO hearts, neither PostCon nor BAY improved recovery of LVDP (50.8±1.6 % baseline for CTL vs. 54.5±1.7 % with PostCon vs. 53.0±1.4 with BAY; n=6 each group), and neither affected EDP or release of cTnI. During reperfusion, both PostCon and BAY increased survival kinase signaling through Akt and ERK1/2 phosphorylation in WT but not A 2B KO hearts. In non-ischemic WT hearts, Akt and ERK1/2 phosphorylation was increased by both BAY treatment and application of the PostCon stimulus. These data demonstrate that the protective effects of PostCon are attenuated by targeted deletion of A 2B AR and are mimicked by selective A 2B AR activation, suggesting A 2B AR activation is an important trigger leading to PostCon-induced myocardial protection.


2001 ◽  
Vol 280 (2) ◽  
pp. H591-H602 ◽  
Author(s):  
James D. McCully ◽  
Yoshiya Toyoda ◽  
Masahisa Uematsu ◽  
Robert D. Stewart ◽  
Sidney Levitsky

Adenosine-enhanced ischemic preconditioning (APC) extends the cardioprotection of ischemic preconditioning (IPC) by both significantly decreasing myocardial infarct size and significantly enhancing postischemic functional recovery. In this study, the role of adenosine receptors during ischemia-reperfusion was determined. Rabbit hearts ( n = 92) were used for Langendorff perfusion. Control hearts were perfused for 180 min, global ischemia hearts received 30-min ischemia and 120-min reperfusion, and IPC hearts received 5-min ischemia and 5-min reperfusion before ischemia. APC hearts received a bolus injection of adenosine coincident with IPC. Adenosine receptor (A1, A2, and A3) antagonists were used with APC before ischemia and/or during reperfusion. GR-69019X (A1/A3) and MRS-1191/MRS-1220 (A3) significantly increased infarct size in APC hearts when administered before ischemia and significantly decreased functional recovery when administered during both ischemia and reperfusion ( P < 0.05 vs. APC). DPCPX (A1) administered either before ischemia and/or during reperfusion had no effect on APC cardioprotection. APC-enhanced infarct size reduction is modulated by adenosine receptors primarily during ischemia, whereas APC-enhanced postischemic functional recovery is modulated by adenosine receptors during both ischemia and reperfusion.


2006 ◽  
Vol 291 (4) ◽  
pp. H1875-H1882 ◽  
Author(s):  
R. Ray Morrison ◽  
Bunyen Teng ◽  
Peter J. Oldenburg ◽  
Laxmansa C. Katwa ◽  
Jurgen B. Schnermann ◽  
...  

To examine ischemic tolerance in the absence of A1 adenosine receptors (A1ARs), isolated wild-type (WT) and A1AR knockout (A1KO) murine hearts underwent global ischemia-reperfusion, and injury was measured in terms of functional recovery and efflux of lactate dehydrogenase (LDH). Hearts were analyzed by real-time RT-PCR both at baseline and at intervals during ischemia-reperfusion to determine whether compensatory expression of other adenosine receptor subtypes occurs with either A1AR deletion and/or ischemia-reperfusion. A1KO hearts had higher baseline coronary flow (CF) and left ventricular developed pressure (LVDP) than WT hearts, whereas heart rate was unchanged by A1AR deletion. After 20 min of ischemia, CF was attenuated in A1KO compared with WT hearts, and this reduction persisted throughout reperfusion. Final recovery of LVDP was decreased in A1KO hearts (54.4 ± 5.1 vs. WT 81.1 ± 3.4% preischemic baseline) and correlated with higher diastolic pressure during reperfusion. Postischemic efflux of LDH was greater in A1KO compared with WT hearts. Real-time RT-PCR demonstrated the absence of A1AR transcript in A1KO hearts, and the message for A2A, A2B, and A3 adenosine receptors was similar in uninstrumented A1KO and WT hearts. Ischemia-reperfusion increased A2B mRNA expression 2.5-fold in both WT and A1KO hearts without changing A1 or A3 expression. In WT hearts, ischemia transiently doubled A2A mRNA, which returned to preischemic level upon reperfusion, a pattern not observed in A1KO hearts. Together, these data affirm the cardioprotective role of A1ARs and suggest that induced expression of other adenosine receptor subtypes may participate in the response to ischemia-reperfusion in isolated murine hearts.


2001 ◽  
Vol 281 (4) ◽  
pp. H1751-H1758 ◽  
Author(s):  
Rachael J. Cerniway ◽  
Zequan Yang ◽  
Marlene A. Jacobson ◽  
Joel Linden ◽  
G. Paul Matherne

A3 adenosine receptors (A3ARs) have been implicated in regulating mast cell function and in cardioprotection during ischemia-reperfusion injury. The physiological role of A3ARs is unclear due to the lack of widely available selective antagonists. Therefore, we examined mice with targeted gene deletion of the A3AR together with pharmacological studies to determine the role of A3ARs in myocardial ischemia-reperfusion injury. We evaluated the functional response to 15-min global ischemia and 30-min reperfusion in isovolumic Langendorff hearts from A3AR−/−and wild-type (A3AR+/+) mice. Loss of contractile function during ischemia was unchanged, but recovery of developed pressure in hearts after reperfusion was improved in A3AR−/− compared with wild-type hearts (80 ± 3 vs. 51 ± 3% at 30 min). Tissue viability assessed by efflux of lactate dehydrogenase was also improved in A3AR−/− hearts (4.5 ± 1 vs. 7.5 ± 1 U/g). The adenosine receptor antagonist BW-A1433 (50 μM) decreased functional recovery following ischemia in A3AR−/− but not in wild-type hearts. We also examined myocardial infarct size using an intact model with 30-min left anterior descending coronary artery occlusion and 24-h reperfusion. Infarct size was reduced by over 60% in A3AR−/− hearts. In summary, targeted deletion of the A3AR improved functional recovery and tissue viability during reperfusion following ischemia. These data suggest that activation of A3ARs contributes to myocardial injury in this setting in the rodent. Since A3ARs are thought to be present on resident mast cells in the rodent myocardium, we speculate that A3ARs may have proinflammatory actions that mediate the deleterious effects of A3AR activation during ischemia-reperfusion injury.


2000 ◽  
Vol 279 (3) ◽  
pp. H1071-H1078 ◽  
Author(s):  
R. Ray Morrison ◽  
Rachael Jones ◽  
Anne M. Byford ◽  
Alyssa R. Stell ◽  
Jason Peart ◽  
...  

The role of A1adenosine receptors (A1AR) in ischemic preconditioning was investigated in isolated crystalloid-perfused wild-type and transgenic mouse hearts with increased A1AR. The effect of preconditioning on postischemic myocardial function, lactate dehydrogenase (LDH) release, and infarct size was examined. Functional recovery was greater in transgenic versus wild-type hearts (44.8 ± 3.4% baseline vs. 25.6 ± 1.7%). Preconditioning improved functional recovery in wild-type hearts from 25.6 ± 1.7% to 37.4 ± 2.2% but did not change recovery in transgenic hearts (44.8 ± 3.4% vs. 44.5 ± 3.9%). In isovolumically contracting hearts, pretreatment with selective A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine attenuated the improved functional recovery in both wild-type preconditioned (74.2 ± 7.3% baseline rate of pressure development over time untreated vs. 29.7 ± 7.3% treated) and transgenic hearts (84.1 ± 12.8% untreated vs. 42.1 ± 6.8% treated). Preconditioning wild-type hearts reduced LDH release (from 7,012 ± 1,451 to 1,691 ± 1,256 U · l−1 · g−1 · min−1) and infarct size (from 62.6 ± 5.1% to 32.3 ± 11.5%). Preconditioning did not affect LDH release or infarct size in hearts overexpressing A1AR. Compared with wild-type hearts, A1AR overexpression markedly reduced LDH release (from 7,012 ± 1,451 to 917 ± 1,123 U · l−1 · g−1 · min−1) and infarct size (from 62.6 ± 5.1% to 6.5 ± 2.1%). These data demonstrate that murine preconditioning involves endogenous activation of A1AR. The beneficial effects of preconditioning and A1AR overexpression are not additive. Taken with the observation that A1AR blockade equally eliminates the functional protection resulting from both preconditioning and transgenic A1AR overexpression, we conclude that the two interventions affect cardioprotection via common mechanisms or pathways.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Juan Zhang ◽  
Jiangang Song ◽  
Jin Xu ◽  
Xuemei Chen ◽  
Peihao Yin ◽  
...  

Early growth response- (Egr-) 1 is an upstream master switch in controlling inflammatory responses following myocardial ischemia-reperfusion (I/R). Activation of extracellular signal-regulated protein kinase-1 and kinase-2 (ERK1/2) signaling is known to upregulate Egr-1. ERK1/2 pathway has been previously shown to mediate the therapeutic action of electroacupucture (EA). Thus, we hypothesized that EA would reduce myocardial I/R injury and inflammatory responses through inhibiting Egr-1 expression via the ERK1/2 pathway. Mice were pretreated with EA, U0126, or combination of EA and U0126 and then underwent 1 h myocardial ischemia and 3 h reperfusion. We investigated that EA significantly attenuated the I/R-induced upregulation of both Egr-1 and phosporylated-ERK1/2 (p-ERK1/2), decreased myocardial inflammatory cytokines including tumor necrosis factor-α(TNF-α) and interleukin-1β(IL-1β), and reduced the infarct size and the release of cardiac troponin I (cTnI). U0126 treatment also exhibited the same effect as EA on Egr-1 level and subsequent cardioprotective effects. There was no additive effect of cotreatment with EA and U0126 on the expression of Egr-1 and its downstream target genes (TNF-α, IL-1β) or serum cTnI level. Collectively, these observations suggested that EA attenuates myocardial I/R injury, possibly through inhibiting the ERK1/2-Egr-1 signaling pathway and reducing the release of proinflammatory cytokines.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Claudia Penna ◽  
Manuela Aragno ◽  
Alessia Sofia Cento ◽  
Saveria Femminò ◽  
Isabella Russo ◽  
...  

Inhibition of either P2Y12 receptor or the nucleotide-binding oligomerization domain- (NOD-) like receptor pyrin domain containing 3 (NLRP3) inflammasome provides cardioprotective effects. Here, we investigate whether direct NLRP3 inflammasome inhibition exerts additive effects on myocardial protection induced by the P2Y12 receptor antagonist Ticagrelor. Ticagrelor (150 mg/kg) was orally administered to rats for three consecutive days. Then, isolated hearts underwent an ischemia/reperfusion (30 min ischemia/60 min reperfusion; IR) protocol. The selective NLRP3 inflammasome inhibitor INF (50 μM) was infused before the IR protocol to the hearts from untreated animals or pretreated with Ticagrelor. In parallel experiments, the hearts isolated from untreated animals were perfused with Ticagrelor (3.70 μM) before ischemia and subjected to IR. The hearts of animals pretreated with Ticagrelor showed a significantly reduced infarct size (IS, 49±3% of area at risk, AAR) when compared to control IR group (69±2% of AAR). Similarly, ex vivo administration of INF before the IR injury resulted in significant IS reduction (38±3% of AAR). Myocardial IR induced the NLRP3 inflammasome complex formation, which was attenuated by either INF pretreatment ex vivo, or by repeated oral treatment with Ticagrelor. The beneficial effects induced by either treatment were associated with the protective Reperfusion Injury Salvage Kinase (RISK) pathway activation and redox defence upregulation. In contrast, no protective effects nor NLRP3/RISK modulation were recorded when Ticagrelor was administered before ischemia in isolated heart, indicating that Ticagrelor direct target is not in the myocardium. Our results confirm that Ticagrelor conditioning effects are likely mediated through platelets, but are not additives to the ones achieved by directly inhibiting NLRP3.


2012 ◽  
Vol 303 (5) ◽  
pp. H605-H618 ◽  
Author(s):  
Lanfang Li ◽  
Heng Zeng ◽  
Jian-Xiong Chen

Apelin is an endogenous ligand for the angiotensin-like 1 receptor (APJ) and has beneficial effects against myocardial ischemia-reperfusion injury. Little is known about the role of apelin in the homing of vascular progenitor cells (PCs) and cardiac functional recovery postmyocardial infarction (post-MI). The present study investigated whether apelin affects PC homing to the infarcted myocardium, thereby mediating repair and functional recovery post-MI. Mice were infarcted by coronary artery ligation, and apelin-13 (1 mg·kg−1·day−1) was injected for 3 days before MI and for 14 days post-MI. Homing of vascular PCs [CD133+/c-Kit+/Sca1+, CD133+/stromal cell-derived factor (SDF)-1α+, and CD133+/CXC chemokine receptor (CXCR)-4+] into the ischemic area was examined. Myocardial Akt, endothelial nitric oxide synthase (eNOS), VEGF, jagged1, notch3, SDF-1α, and CXCR-4 expression were assessed at 24 h and 14 days post-MI. Functional analyses were performed on day 14 post-MI. Mice that received apelin-13 treatment demonstrated upregulation of SDF-1α/CXCR-4 expression and dramatically increased the number of CD133+/c-Kit+/Sca1+, CD133+/SDF-1α+, and c-Kit+/CXCR-4+ cells in infarcted hearts. Apelin-13 also significantly increased Akt and eNOS phosphorylation and upregulated VEGF, jagged1, and notch3 expression in ischemic hearts. This was accompanied by a significant reduction of myocardial apoptosis. Furthermore, treatment with apelin-13 promoted myocardial angiogenesis and attenuated cardiac fibrosis and hypertrophy together with a significant improvement of cardiac function at 14 days post-MI. Apelin-13 increases angiogenesis and improves cardiac repair post-MI by a mechanism involving the upregulation of SDF-1α/CXCR-4 and homing of vascular PCs.


2016 ◽  
Vol 125 (3) ◽  
pp. 547-560 ◽  
Author(s):  
Tiago F. Granja ◽  
David Köhler ◽  
Jessica Schad ◽  
Claudia Bernardo de Oliveira Franz ◽  
Franziska Konrad ◽  
...  

Abstract Background Liver ischemia/reperfusion (IR) injury is characterized by hepatic tissue damage and an inflammatory response. This is accompanied by the formation and vascular sequestration of platelet–neutrophil conjugates (PNCs). Signaling through Adora2b adenosine receptors can provide liver protection. Volatile anesthetics may interact with adenosine receptors. This study investigates potential antiinflammatory effects of the volatile anesthetic sevoflurane during liver IR. Methods Experiments were performed ex vivo with human blood and in a liver IR model with wild-type, Adora2a−/−, and Adora2b−/− mice. The effect of sevoflurane on platelet activation, PNC formation and sequestration, cytokine release, and liver damage (alanine aminotransferase release) was analyzed using flow cytometry, luminometry, and immunofluorescence. Adenosine receptor expression in liver tissue was analyzed using immunohistochemistry and real-time polymerase chain reaction. Results Ex vivo experiments indicate that sevoflurane inhibits platelet and leukocyte activation (n = 5). During liver IR, sevoflurane (2 Vol%) decreased PNC formation 2.4-fold in wild-type (P &lt; 0.05) but not in Adora2b−/− mice (n ≥ 5). Sevoflurane reduced PNC sequestration 1.9-fold (P &lt; 0.05) and alanine aminotransferase release 3.5-fold (P &lt; 0.05) in wild-type but not in Adora2b−/− mice (n = 5). In Adora2a−/− mice, sevoflurane also inhibited PNC formation and cytokine release. Sevoflurane diminished cytokine release (n ≥ 3) and increased Adora2b transcription and expression in liver tissue of wild-types (n = 4). Conclusions Our experiments highlight antiinflammatory and tissue-protective properties of sevoflurane during liver IR and reveal a mechanistic role of Adora2b in sevoflurane-associated effects. The targeted use of sevoflurane not only as an anesthetic but also to prevent IR damage is a promising approach in the treatment of critically ill patients.


2006 ◽  
Vol 34 (03) ◽  
pp. 493-502 ◽  
Author(s):  
Xiang-Jian Chen ◽  
Zhi-Ping Bian ◽  
Shu Lu ◽  
Jin-Dan Xu ◽  
Chun-Rong Gu ◽  
...  

In clinical practice, Astragali Radix (Astragalus), the root of Astragalus membranaceus Bunge, has been widely applied to treat patients with viral diseases, including viral myocarditis in China. The present study was designed to evaluate the protective effects of Astragalus on the function of sarcoplasmic reticulum calcium ATPase (SERCA2) activity and endothelin system at acute and chronic periods of myocarditis mice induced by CVB 3 infection. Astragalus feeding (2.2 mg/kg/day) could significantly increase the survival rate, alleviate pathological alterations and serum cardiac troponin I (cTnI), as well as restore impaired SERCA activity at the acute stage. Low affinity and capacity of ETR were reversed with Astragalus after the first CVB 3 inoculation up to 7 days and after the second virus inoculation up to 150 days. In the meantime, the contents of cardiac ET-1 and ANP were reduced. Comparison the myocarditis mice treated with Perindopril (0.44 mg/kg/day), an ACE inhibitor, shows that Astragalus achieved a similar effect on survival rate, SERCA2 and ET system. These results indicated that the beneficial effects of Astragalus and Perindopril for treating viral myocarditis might be partly mediated by preserving the functions of SERCA 2 activity and ET system.


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