Abstract P451: Depletion Of Rbl2 Exacerbates Cardiomyocyte Apoptosis And Ischemia-reperfusion Injury By Augmenting E2f1-mediated Bnip3 Expression

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Jingrui Chen ◽  
Yuening Liu ◽  
Peng Xia ◽  
Zhaokang Cheng
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiomyocyte Apoptosis ◽  
Neonatal Rat ◽  
Mouse Heart ◽  
Wild Type ◽  
Rat Cardiomyocytes

Background: Reperfusion therapy, an effective treatment for myocardial infarction, triggers ischemia-reperfusion (I/R) injury and eventually may result in heart failure. Retinoblastoma-like 2 (Rbl2), a major retinoblastoma family member expressed in the heart, maintains the postmitotic state of adult cardiac myocytes. However, the role of Rbl2 in myocardial I/R injury remains unclear. We hypothesize that Rbl2 deficiency exacerbates myocardial injury following I/R. Methods and results: Wild type C57BL/6 (8–10-week, male) mice were subjected to 30 min of ischemia followed reperfusion. I/R induced phosphorylation of Rbl2 at Ser952, which has been associated with Rbl2 protein inactivation. To determine the role of Rbl2 in vivo, Rbl2-deficient mice and wild-type littermates were subjected to I/R and infarct size was evaluated by Evans blue/TTC staining. Rbl2 deficiency significantly increased infarct size at 24 h post I/R when compared with wild-type littermate controls. Echocardiography and Masson’s trichrome staining revealed that Rbl2 deficiency exacerbated I/R-induced cardiac dysfunction and fibrosis. Moreover, ablation of Rbl2 exacerbated I/R-induced cardiomyocyte apoptosis, as evidenced by the increased TUNEL positive signal. Consistently, knockdown of Rbl2 augmented H 2 O 2 -induced cleavage of PARP and caspase 3 in neonatal rat cardiomyocytes , suggesting that depletion of Rbl2 exacerbated oxidative stress-induced cardiomyocyte apoptosis. Mechanistically, both I/R and H 2 O 2 induced expression of the pro-apoptotic protein BNIP3, which was augmented by depletion of Rbl2. Since the BNIP3 promoter contains an E2F-binding site, we further examined the levels of the transcriptional activator E2F1 and the transcriptional repressor E2F4. Western blotting revealed that disruption of Rbl2 reduced E2F4 but increased E2F1 levels in mouse heart both at baseline and following I/R. Conclusion: Our findings suggest that Rbl2 deficiency exacerbates cardiomyocyte apoptosis and ischemia-reperfusion injury by augmenting E2F1-mediated BNIP3 expression.

Targeted deletion of A3 adenosine receptors improves tolerance to ischemia-reperfusion injury in mouse myocardium

2001 ◽  
Vol 281 (4) ◽  
pp. H1751-H1758 ◽  
Author(s):  
Rachael J. Cerniway ◽  
Zequan Yang ◽  
Marlene A. Jacobson ◽  
Joel Linden ◽  
G. Paul Matherne
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Functional Recovery ◽  
Adenosine Receptors ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Wild Type ◽  
Tissue Viability ◽  
Targeted Deletion

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.

Percutaneous Intracoronary Delivery of Plasma Extracellular Vesicles Protects the Myocardium Against Ischemia-Reperfusion Injury in Canis

Hypertension ◽  
2021 ◽  
Vol 78 (5) ◽  
pp. 1541-1554
Author(s):  
Hongyun Wang ◽  
Rusitanmujiang Maimaitiaili ◽  
Jianhua Yao ◽  
Yuling Xie ◽  
Sujing Qiang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Human Embryonic Stem Cell ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Embryonic Stem ◽  
Cardiomyocyte Apoptosis ◽  
Neonatal Rat ◽  
Rat Cardiomyocytes ◽  
Neonatal Rat Cardiomyocytes

Plasma circulating extracellular vesicles (EVs) have been utilized as a potential therapeutic strategy to treat ischemic disease through intramyocardial injection (efficient but invasive) or tail vein injection (noninvasive but low cardiac retention). An effective and noninvasive delivery of EVs for future clinical use is necessary. The large animal (canine) model was complemented with a murine ischemia-reperfusion injury (IRI) model, as well as H9 human embryonic stem cell–induced cardiomyocytes or neonatal rat cardiomyocytes to investigate the effective delivery method and the role of plasma EVs in the IRI model. We further determine the crucial molecule within EVs that confers the cardioprotective role in vivo and in vitro and investigate the efficiency of CHP (cardiac homing peptide)-linked EVs in alleviating IRI. D-SPECT imaging showed that percutaneous intracoronary delivery of EVs reduced infarct extent in dogs. CHP-EVs further reduced IRI-induced cardiomyocyte apoptosis in mice and neonatal rat cardiomyocytes. Mechanistically, administration of EVs by percutaneous intracoronary delivery (in dog) and myocardial injection (in mice) just before reperfusion reduced infarct size of IRI by increasing miR-486 levels. miR-486–deleted EVs exacerbated oxygen-glucose deprivation/reoxygenation–induced human embryonic stem cell–induced cardiomyocytes and neonatal rat cardiomyocyte apoptosis. EV-miR-486 inhibited the PTEN (phosphatase and tensin homolog deleted on chromosome ten) expression and then promoted AKT (protein kinase B) activation in human embryonic stem cell–induced cardiomyocytes and neonatal rat cardiomyocytes. In conclusion, plasma-derived EVs convey miR-486 to the myocardium and attenuated IRI-induced infarction and cardiomyocyte apoptosis. CHP strategy was effective to improve cardiac retention of EVs in mice (in vivo) and dogs (ex vivo).

Role of α/β and γ/δ T cells in renal ischemia-reperfusion injury

2007 ◽  
Vol 293 (3) ◽  
pp. F741-F747 ◽  
Author(s):  
Kathrin Hochegger ◽  
Tobias Schätz ◽  
Philipp Eller ◽  
Andrea Tagwerker ◽  
Dorothea Heininger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Wild Type ◽  
Renal Ischemia Reperfusion Injury ◽  
Deficient Mice

T cells have been implicated in the pathogenesis of renal ischemia-reperfusion injury (IRI). To date existing data about the role of the T cell receptor (Tcr) are contradictory. We hypothesize that the Tcr plays a prominent role in the late phase of renal IRI. Therefore, renal IRI was induced in α/β, γ/δ T cell-deficient and wild-type mice by clamping renal pedicles for 30 min and reperfusing for 24, 48, 72, and 120 h. Serum creatinine increased equally in all three groups 24 h after ischemia but significantly improved in Tcr-deficient animals compared with wild-type controls after 72 h. A significant reduction in renal tubular injury and infiltration of CD4+ T-cells in both Tcr-deficient mice compared with wild-type controls was detected. Infiltration of α/β T cells into the kidney was reduced in γ/δ T cell-deficient mice until 72 h after ischemia. In contrast, γ/δ T cell infiltration was equal in wild-type and α/β T cell-deficient mice, suggesting an interaction between α/β and γ/δ T cells. Data from γ/δ T cell-deficient mice were confirmed by in vivo depletion of γ/δ T cells in C57BL/6 mice. Whereas α/β T cell-deficient mice were still protected after 120 h, γ/δ T cell-deficient mice showed a “delayed wild-type phenotype” with a dramatic increase in kidney-infiltrating α/β, Tcr-expressing CD4+ T-cells. This report provides further evidence that α/β T cells are major effector cells in renal IRI, whereas γ/δ T cells play a role as mediator cells in the first 72 h of renal IRI.

Abstract 16598: The Role of Paraoxonase 2 in Myocardial Ischemia/Reperfusion Injury

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jingyuan Li ◽  
Victor R Grijalva ◽  
Srinivasa T Reddy ◽  
Mansoureh Eghbali
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Er Stress ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Production ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Objectives: Paraoxonases (PON) gene family consists of three proteins PON1, PON2, and PON3. PON2 is an intracellular membrane-associated protein that is widely expressed in vascular cells and many tissues. At the subcellular level, PON2 is localized to both the ER and mitochondria, and protects against oxidative stress. Hypothesis: The aim of this study was to investigate the role of PON2 in myocardial ischemia reperfusion injury. Methods: PON2 deficient (PON2-/-) and WT male mice were subjected to in-vivo ischemia/reperfusion injury. The left anterior descending coronary artery was occluded for 30 min followed by 24 hr of reperfusion. The infarct size, mitochondrial calcium retention capacity (CRC) and reactive oxygen species (ROS) generation were measured. The expression of C/EBP homologous protein (CHOP), GSK3b and phosphate GSK3b protein were examined by Western Blot. The number of animals was 5-7/group and data were expressed as mean±SEM. T test were used for statistical analysis. Probability values <0.05 were considered statistically significant. Results: The infarct size was ~2 fold larger in PON2 deficient mice compared to WT mice (p<0.05). The threshold for opening of mitochondrial permeability transition pore (mPTP) in response to calcium overload was much lower in PON2-/- mice compared with WT mice (173±19 in PON2-/-, 250±41 in WT, nmol/mg-mitochondrial protein, p<0.05). The ROS production was ~2 fold higher in isolated cardiac mitochondria from PON2-/- mice compared with WT mice (p<0.05). ER stress protein CHOP increased significantly in PON2-/- mice compared to WT mice (normalized to WT: 1±0.05 in WT, 1.66±0.08 in PON2-/-, p<0.001). Phospho-GSK3b level was significantly downregulated in in PON2-/- mice compared to WT mice (pGSK3b/GSK3b normalized to WT: 1±0.06 in WT 0.67±0.08 in PON2-/-, p<0.05). Conclusions: PON2 regulates myocardial ischemia/reperfusion injury via inhibiting the opening of mPTP, which is associated with reduced mitochondria ROS production, deactivation of ER stress signaling CHOP and GSK3b.

Cardioprotection induced by cardiac-specific overexpression of fibroblast growth factor-2 is mediated by the MAPK cascade

2005 ◽  
Vol 289 (5) ◽  
pp. H2167-H2175 ◽  
Author(s):  
Stacey L. House ◽  
Kevin Branch ◽  
Gilbert Newman ◽  
Thomas Doetschman ◽  
Jo El J. Schultz
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Mapk Signaling ◽  
Low Flow ◽  
Wild Type ◽  
Erk Inhibition ◽  
Sb 203580

Our laboratory showed previously that cardiac-specific overexpression of FGF-2 [FGF-2 transgenic (Tg)] results in increased recovery of contractile function and decreased infarct size after ischemia-reperfusion injury. MAPK signaling is downstream of FGF-2 and has been implicated in other models of cardioprotection. Treatment of FGF-2 Tg and wild-type hearts with U-0126, a MEK-ERK pathway inhibitor, significantly reduced recovery of contractile function after global low-flow ischemia-reperfusion injury in FGF-2 Tg (86 ± 2% vehicle vs. 66 ± 4% U-0126; P < 0.05) but not wild-type (61 ± 7% vehicle vs. 67 ± 7% U-0126) hearts. Similarly, MEK-ERK inhibition significantly increased myocardial infarct size in FGF-2 Tg (12 ± 3% vehicle vs. 31 ± 2% U-0126; P < 0.05) but not wild-type (30 ± 4% vehicle vs. 36 ± 7% U-0126) hearts. In contrast, treatment of FGF-2 Tg and wild-type hearts with SB-203580, a p38 inhibitor, did not abrogate FGF-2-induced cardioprotection from postischemic contractile dysfunction. Instead, inhibition of p38 resulted in decreased infarct size in wild-type hearts (30 ± 4% vehicle vs. 11 ± 2% SB-203580; P < 0.05) but did not alter infarct size in FGF-2 Tg hearts (12 ± 3% vehicle vs. 14 ± 1% SB-203580). Western blot analysis of ERK and p38 activation revealed signaling alterations in FGF-2 Tg and wild-type hearts during early ischemia or reperfusion injury. In addition, MEK-independent ERK inhibition by p38 was observed during early ischemic injury. Together these data suggest that activation of ERK and inhibition of p38 by FGF-2 is cardioprotective during ischemia-reperfusion injury.

Abstract 354: Prostaglandin D 2 -F Type Prostanoid Receptor Signaling Is a Novel Cardiomyocyte Survival Pathway

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Yoshinori Katsumata ◽  
Motoaki Sano ◽  
Tomohiro Matsuhashi ◽  
Atsushi Anzai ◽  
Cardex Yan ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Expression Profiles ◽  
Ischemia Reperfusion ◽  
Cardioprotective Effect ◽  
Neonatal Rat ◽  
Th2 Cells ◽  
Dependent Manner ◽  
Rat Cardiomyocytes ◽  
Fp Receptor

Background: Lipocalin-type prostaglandin D synthase (L-PGDS) is abundantly expressed on cardiomyocytes. We recently demonstrated that dexamethasone stimulates PGD 2 -dominated activation of prostanoid biosynthesis, thereby protecting hearts against ischemia/reperfusion injury. Here, we examined the downstream signaling responsible for cardioprotection mediated through PGD 2 -dominated activation. Methods and Results: (1) In cultured neonatal rat cardiomyocytes, PGD 2 strongly activates ERK in a dose-dependent manner, although canonical PGD 2 receptors, including DP (PGD 2 receptor) and CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells) receptors, are hardly expressed on cardiomyocytes. (2) Interestingly, PGD 2 bounds to FP receptor (the canonical PGF 2 α receptor) with an affinity comparable to that for the DP receptor, and the FP receptor is abundantly expressed on cardiomyocytes. (3) PGD 2 -induced ERK activation is completely blocked by FP antagonist or siRNA-mediated knockdown of the FP, but not by DP and CRTH2 antagonist and siRNA-mediated knockdown of DP and CRTH2. (4) PGD 2 activates ERK in Langendorff perfused DP-knock out (KO) and CRTH2-KO mice hearts to comparable levels as those observed for wild-type hearts, while cannot activate it in FP-KO hearts. (5) Consistently, the cardioprotective effect of PGD 2 -dominated activation by dexamethasone was blunted in FP KO hearts. (6) Furtermore, genomewide gene expression profiles by microarray analysis and quantitative real-time RT-PCR analysis identified that Nrf-2 was the downstream target of L-PGDS-mediated PGD 2 biosynthesis. (7) In cultured cardiomyocytes, FP agonist stimulated Nrf2 nuclear translocation and consequently induced Nrf2-target genes expression in an ERK-dependent manner. (8) Finally, The cardioprotective effect by dexamethasone was completely abolished in Nrf-2 KO hearts. Conclusion: FP serves as a functionally relevant PGD 2 receptor in the hearts and PGD 2 -FP signaling plays a substantial role in the improvement of functional recovery after ischemia-reperfusion injury in the heart. Nrf-2 is a major effector molecule responsible for the cardioprotecton elicited by L-PGDS-derived PGD 2 .

scholarly journals Hyperglycemia-Induced Inhibition of DJ-1 Expression Compromised the Effectiveness of Ischemic Postconditioning Cardioprotection in Rats

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Min Liu ◽  
Bin Zhou ◽  
Zhong-Yuan Xia ◽  
Bo Zhao ◽  
Shao-Qing Lei ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Diabetic Rats ◽  
Ischemia And Reperfusion Injury ◽  
Correlation Relationship ◽  
Myocardial Ischemia Reperfusion

Ischemia postconditioning (IpostC) is an effective way to alleviate ischemia and reperfusion injury; however, the protective effects seem to be impaired in candidates with diabetes mellitus. To gain deep insight into this phenomenon, we explored the role of DJ-1, a novel oncogene, that may exhibit powerful antioxidant capacity in postconditioning cardioprotection in a rat model of myocardial ischemia reperfusion injury. Compared with normal group, cardiac DJ-1 was downregulated in diabetes. Larger postischemic infarct size as well as exaggeration of oxidative stress was observed, while IpostC reversed the above changes in normal but not in diabetic rats. DJ-1 was increased after ischemia and postconditioning contributed to a further elevation; however, no alteration of DJ-1 was documented in all subgroups of diabetic rats. Alteration of the cardioprotective PI3K/Akt signaling proteins may be responsible for the ineffectiveness of postconditioning in diabetes. There is a positive correlation relationship between p-Akt and DJ-1 but a negative correlation between infarct size and DJ-1, which may partially explain the interaction of DJ-1 and IpostC cardioprotection. Our result indicates a beneficial role of DJ-1 in myocardial ischemia reperfusion. Downregulation of cardiac DJ-1 may be responsible for the compromised diabetic heart responsiveness to IpostC cardioprotection.

Intestinal reperfusion injury is mediated by IgM and complement

1999 ◽  
Vol 86 (3) ◽  
pp. 938-942 ◽  
Author(s):  
Julian P. Williams ◽  
Taine T. V. Pechet ◽  
Martin R. Weiser ◽  
Russell Reid ◽  
Les Kobzik ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Intestinal Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Complement Factor ◽  
Wild Type ◽  
Complement Receptor 1 ◽  
Immunohistological Staining ◽  
Intestinal Ischemia Reperfusion

Intestinal ischemia-reperfusion injury is dependent on complement. This study examines the role of the alternative and classic pathways of complement and IgM in a murine model of intestinal ischemia-reperfusion. Wild-type animals, mice deficient in complement factor 4 (C4), C3, or Ig, or wild-type mice treated with soluble complement receptor 1 were subjected to 40 min of jejunal ischemia and 3 h of reperfusion. Compared with wild types, knockout and treated mice had significantly reduced intestinal injury, indicated by lowered permeability to radiolabeled albumin. When animals deficient in Ig were reconstituted with IgM, the degree of injury was restored to wild-type levels. Immunohistological staining of intestine for C3 and IgM showed colocalization in the mucosa of wild-type controls and minimal staining for both in the intestine of Ig-deficient and C4-deficient mice. We conclude that intestinal ischemia-reperfusion injury is dependent on the classic complement pathway and IgM.

scholarly journals Activation of Autophagic Flux Blunts Cardiac Ischemia/Reperfusion Injury

2021 ◽  
Author(s):  
Min Xie ◽  
Geoffrey W Cho ◽  
Yongli Kong ◽  
Dan L Li ◽  
Francisco Altamirano ◽  
...  
Keyword(s):  
Cell Death ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Border Zone ◽  
Relative Reduction ◽  
Autophagic Flux ◽  
Hdac Inhibition

Rationale: Reperfusion injury accounts for up to half of myocardial infarct size, and meaningful clinical therapies targeting it do not exist. We have reported previously that autophagy is reduced during reperfusion and that HDAC inhibition enhances cardiomyocyte autophagy and blunts ischemia/reperfusion (I/R) injury when administered at the time of reperfusion. However, whether inducing autophagy per se, as opposed to other effects triggered by HDAC inhibition, is sufficent to protect against reperfusion injury is not clear. Objective: We set out to test whether augmentation of autophagy using a specific autophagy-inducing peptide, Tat-Beclin, protects the myocardium through reduction of reactive oxygen species (ROS) during reperfusion injury. Methods and Results: Eight to twelve-week-old, wild-type, C57BL6 mice and drug-inducible cardiomyocyte-specific ATG7 knockout mice (to test the dependency on autophagy) were randomized into two groups: exposed to a control Tat-Scrambled (TS) peptide or a Tat-Beclin (TB) peptide. Each group was subjected to I/R surgery (45min coronary ligation, 24h reperfusion). Infarct size, systolic function, autophagic flux, and ROS were assayed. Cultured neonatal rat ventricular myocytes (NRVMs) were exposed to TB during simulated ischemia/reperfusion injury. ATG7 knockdown by siRNA in NRVMs was used to evaluate the role of autophagy. TB treatment at reperfusion reduced infarct size by 20% (absolute reduction; 50% relative reduction) and improved contractile function. Improvement correlated with increased autophagic flux in the border zone with less oxidative stress. ATG7 KO mice did not manifest TB-promoted cardioprotection during I/R. In NRVMs subjected to I/R, TB reduced cell death by 41% and reduced I/R-induced ROS generation. Conversely, ATG7 knockdown in NRVMs abolished these beneficial effects of TB on cell death and ROS reduction. Conclusions: Induction of autophagy at the time of reperfusion is sufficient to mitigate myocardial reperfusion injury by reducing ROS and cell death. Maintenance of appropriate autophagic flux may emerge as a viable clinical therapy to reduce reperfusion injury in acute myocardial infarction.

scholarly journals RRM2 Improves Cardiomyocyte Proliferation after Myocardial Ischemia Reperfusion Injury through the Hippo-YAP Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Huamin Yu ◽  
Haiyan Tang ◽  
Chaochao Deng ◽  
Qing Lin ◽  
Peng Yu ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Cell Counting ◽  
Cardiomyocyte Proliferation ◽  
Rat Cardiomyocytes ◽  
Qrt Pcr ◽  
Myocardial Ischemia Reperfusion ◽  
Deoxyribonucleoside Triphosphate

Objective. Ribonucleotide reductase M2 (RRM2) as an enzyme that catalyzes the deoxyreduction of nucleosides to deoxyribonucleoside triphosphate (dNTP) has been extensively studied, and it plays a crucial role in regulating cell proliferation. However, its role in ischemia-reperfusion injury (I/RI) is still unclear. Methods. SD rats were used as the research object to detect the expression of RRM2 in the myocardium by constructing an I/RI model. At the same time, primary SD neonatal rat cardiomyocytes were extracted, and hypoxia/reoxygenation (H/R) treatment simulated the I/RI model. Using transfection technology to overexpress RRM2 in cardiomyocytes, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of RRM2, Cell Counting Kit-8 (CCK-8) assay was used to detect cell viability, and immunofluorescence staining was used to detect Ki67 and EdU-positive cells. Western blot (WB) technology was used to detect YAP and its phosphorylation expression. Results. qRT-PCR results indicated that the expression of RRM2 was inhibited in the model group, and cardiomyocytes overexpressing RRM2 can obviously promote the proliferation of primary cardiomyocytes and improve the damage of cardiac structure and function caused by I/R. At the same time, RRM2 can promote the increase of YAP protein expression and the increase of Cyclin D1 mRNA expression. Conclusion. RRM2 expression was downregulated in myocardial tissue with I/R. After overexpression of RRM2, cardiomyocyte proliferation was upregulated and the Hippo-YAP signaling pathway was activated.

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