MicroRNA-34a protects myocardial cells against ischemia–reperfusion injury through inhibiting autophagy via regulating TNFα expression

2018 ◽  
Vol 96 (3) ◽  
pp. 349-354 ◽  
Author(s):  
Haifeng Shao ◽  
Lili Yang ◽  
Li Wang ◽  
Bozan Tang ◽  
Jian Wang ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Heart Tissue ◽  
Neonatal Rat ◽  
Cell Counting ◽  
In Vivo Model ◽  
Myocardial Cells ◽  
Rat Cardiomyocytes ◽  
Cardiac Tissues

Background: ischemia–reperfusion (I/R) is a consequence of restored blood supply after myocardial infarction. Myocardial I/R injury can be alleviated by reducing autophagy in heart tissue. MicroRNA-34a (miR-34a) has been shown to regulate autophagy in a renal model of I/R, but it is not known whether it can protect cardiac tissues from I/R injury. This study investigated how miR-34a protects myocardial cells from I/R injury by inhibiting autophagy via regulation of tumor necrosis factor α (TNFα). Methods: we constructed an I/R model in vivo using Langendorff perfusion, and we constructed an in vivo model by treating neonatal rat cardiomyocytes (NRCMs) with hypoxia–reoxygenation (H/R method). Transfected adenoviral-overexpressed miR-34a mimics and controlled NRCMs after H/R. We analyzed cell viability using the MTT assay and a cell counting kit-8 (CCK-8) assay. Changes in the rate of apoptosis were detected by flow cytometry. We investigated the effect mechanisms of miR-34a with Western blot and luciferase assays. Results: miR-34a expression decreased after in vivo reperfusion of the myocardial cells and heart tissues of neonatal rats. MiR-34a reduced apoptosis of the NRCMs and autophagy levels, simultaneously, after H/R injury. Further, miR-34a decreased the expression of Lc3-II and p62, indicating that miR-34a reduces myocardial I/R injury by decreasing TNFα expression. Conclusion: miR-34a can inhibit autophagy levels after I/R by targeting TNFα, thereby reducing myocardial injury.

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.

Necrostatin-1 Analog DIMO Exerts Cardioprotective Effect against Ischemia Reperfusion Injury by Suppressing Necroptosis via Autophagic Pathway in Rats

Pharmacology ◽  
2021 ◽  
Vol 106 (3-4) ◽  
pp. 189-201
Author(s):  
Shigang Qiao ◽  
Wen-jie Zhao ◽  
Huan-qiu Li ◽  
Gui-zhen Ao ◽  
Jian-zhong An ◽  
...  
Keyword(s):  
Cell Death ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Neonatal Rat ◽  
Ligand Docking ◽  
Autophagic Flux ◽  
Myocardial Infarct Size ◽  
Rat Cardiomyocytes

Aim: It has been reported that necrostatin-1 (Nec-1) is a specific necroptosis inhibitor that could attenuate programmed cell death induced by myocardial ischemia/reperfusion (I/R) injury. This study aimed to observe the effect and mechanism of novel Nec-1 analog (Z)-5-(3,5-dimethoxybenzyl)-2-imine-1-methylimidazolin-4-1 (DIMO) on myocardial I/R injury. Methods: Male SD rats underwent I/R injury with or without different doses of DIMO (1, 2, or 4 mg/kg) treatment. Isolated neonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) treatment with or without DIMO (0.1, 1, 10, or 100 μM). Myocardial infarction was measured by TTC staining. Cardiomyocyte injury was assessed by lactate dehydrogenase assay (LDH) and flow cytometry. Receptor-interacting protein 1 kinase (RIP1K) and autophagic markers were detected by co-immunoprecipitation and Western blotting analysis. Molecular docking of DIMO into the ATP binding site of RIP1K was performed using GLIDE. Results: DIMO at doses of 1 or 2 mg/kg improved myocardial infarct size. However, the DIMO 4 mg/kg dose was ineffective. DIMO at the dose of 0.1 μM decreased LDH leakage and the ratio of PI-positive cells followed by OGD/R treatment. I/R or OGD/R increased RIP1K expression and in its interaction with RIP3K, as well as impaired myocardial autophagic flux evidenced by an increase in LC3-II/I ratio, upregulated P62 and Beclin-1, and activated cathepsin B and L. In contrast, DIMO treatment reduced myocardial cell death and reversed the above mentioned changes in RIP1K and autophagic flux caused by I/R and OGD/R. DIMO binds to RIP1K and inhibits RIP1K expression in a homology modeling and ligand docking. Conclusion: DIMO exerts cardioprotection against I/R- or OGD/R-induced injury, and its mechanisms may be associated with the reduction in RIP1K activation and restoration impaired autophagic flux.

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).

scholarly journals Effects of the Delta Opioid Receptor Agonist DADLE in a Novel Hypoxia-Reoxygenation Model on Human and Rat-Engineered Heart Tissue: A Pilot Study

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1309
Author(s):  
Sandra Funcke ◽  
Tessa R. Werner ◽  
Marc Hein ◽  
Bärbel M. Ulmer ◽  
Arne Hansen ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Ischemia Reperfusion ◽  
Heart Tissue ◽  
Contractile Force ◽  
Neonatal Rat ◽  
Rat Cardiomyocytes ◽  
Engineered Heart Tissue ◽  
Hypoxia Reoxygenation

Intermittent hypoxia and various pharmacological compounds protect the heart from ischemia reperfusion injury in experimental approaches, but the translation into clinical trials has largely failed. One reason may lie in species differences and the lack of suitable human in vitro models to test for ischemia/reperfusion. We aimed to develop a novel hypoxia-reoxygenation model based on three-dimensional, spontaneously beating and work performing engineered heart tissue (EHT) from rat and human cardiomyocytes. Contractile force, the most important cardiac performance parameter, served as an integrated outcome measure. EHTs from neonatal rat cardiomyocytes were subjected to 90 min of hypoxia which led to cardiomyocyte apoptosis as revealed by caspase 3-staining, increased troponin I release (time control vs. 24 h after hypoxia: cTnI 2.7 vs. 6.3 ng/mL, ** p = 0.002) and decreased contractile force (64 ± 6% of baseline) in the long-term follow-up. The detrimental effects were attenuated by preceding the long-term hypoxia with three cycles of 10 min hypoxia (i.e., hypoxic preconditioning). Similarly, [d-Ala2, d-Leu5]-enkephalin (DADLE) reduced the effect of hypoxia on force (recovery to 78 ± 5% of baseline with DADLE preconditioning vs. 57 ± 5% without, p = 0.012), apoptosis and cardiomyocyte stress. Human EHTs presented a comparable hypoxia-induced reduction in force (55 ± 5% of baseline), but DADLE failed to precondition them, likely due to the absence of δ-opioid receptors. In summary, this hypoxia-reoxygenation in vitro model displays cellular damage and the decline of contractile function after hypoxia allows the investigation of preconditioning strategies and will therefore help us to understand the discrepancy between successful conditioning in vitro experiments and its failure in clinical trials.

Intravenous bilirubin provides incomplete protection against renal ischemia-reperfusion injury in vivo

2007 ◽  
Vol 292 (2) ◽  
pp. F888-F894 ◽  
Author(s):  
Kristin Kirkby ◽  
Chris Baylis ◽  
Anupam Agarwal ◽  
Byron Croker ◽  
Linda Archer ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Rat Kidney ◽  
Ischemia Reperfusion ◽  
Renal Plasma Flow ◽  
In Vivo Model ◽  
Protective Effects ◽  
Sprague Dawley ◽  
Organ Systems

Exogenous bilirubin (BR) substitutes for the protective effects of heme oxygenase (HO) in several organ systems. Our objective was to investigate the effects of exogenous BR in an in vivo model of ischemia-reperfusion injury (IRI) in the rat kidney. Four groups of male Sprague-Dawley rats were anesthetized using isoflurane in oxygen and treated with 1) 5 mg/kg intravenous (iv) BR, 1 h before ischemia and 6-h reperfusion; 2) vehicle 1 h before ischemia and 6-h reperfusion; 3) 20 mg/kg iv BR, 1 h before and during ischemia; and 4) vehicle 1 h before and during ischemia. Bilateral renal clamping (30 min) was followed by 6-h reperfusion. Infusion of 5 mg/kg iv BR achieved target levels in the serum at 6 h postischemia (31 ± 9 μmol/l). Infusion of 20 mg/kg BR reached 50 ± 22 μmol/l at the end of ischemia, and a significant improvement was seen in serum creatinine at 6 h (1.07 ± 28 vs. 1.38 ± 0.18 mg/dl, P = 0.043). Glomerular filtration rate, estimated renal plasma flow, fractional excretion of electrolytes, and renal vascular resistance were not significantly improved in BR-treated groups. Histological grading demonstrated a trend toward preservation of cortical proximal tubules in rats receiving 20 mg/kg iv BR compared with control; however, neither BR dose provided protection against injury to the renal medulla. At the doses administered, iv BR did not provide complete protection against IRI in vivo. Combined supplementation of both BR and carbon monoxide may be required to preserve renal blood flow and adequately substitute for the protective effects of HO in vivo.

scholarly journals Transient Receptor Potential Ankyrin 1 Activation within the Cardiac Myocyte Limits Ischemia–reperfusion Injury in Rodents

2016 ◽  
Vol 125 (6) ◽  
pp. 1171-1180 ◽  
Author(s):  
Yao Lu ◽  
Honit Piplani ◽  
Stacy L. McAllister ◽  
Carl M. Hurt ◽  
Eric R. Gross
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiac Injury ◽  
In Vivo Model

Abstract Background Recent evidence suggests that cross talk exists between cellular pathways important for pain signaling and ischemia–reperfusion injury. Here, the authors address whether the transient receptor potential ankyrin 1 (TRPA1) channel, important in pain signaling, is present in cardiac myocytes and regulates cardiac ischemia–reperfusion injury. Methods For biochemical analysis of TRPA1, techniques including quantitative polymerase chain reaction, Western blot, and immunofluorescence were used. To determine how TRPA1 mediates cellular injury, the authors used an in vivo model of rat cardiac ischemia–reperfusion injury and adult rat–isolated cardiac myocytes subjected to hypoxia–reoxygenation. Results The authors’ biochemical analysis indicates that TRPA1 is within the cardiac myocytes. Further, using a rat in vivo model of cardiac injury, the TRPA1 activators ASP 7663 and optovin reduce myocardial injury (45 ± 5%* and 44 ± 8%,* respectively, vs. control, 66 ± 6% infarct size/area at risk; n = 6 per group; mean ± SD; *P < 0.001). TRPA1 inhibition also blocked the infarct size–sparing effects of morphine. In isolated cardiac myocytes, the TRPA1 activators ASP 7663 and optovin reduce cardiac myocyte cell death when given during reoxygenation (20 ± 3%* and 22 ± 4%* vs. 36 ± 3%; percentage of dead cells per field, n = 6 per group; mean ± SD; *P < 0.05). For a rat in vivo model of cardiac injury, the infarct size–sparing effect of TRPA1 activators also occurs during reperfusion. Conclusions The authors’ data suggest that TRPA1 is present within the cardiac myocytes and is important in regulating myocardial reperfusion injury. The presence of TRPA1 within the cardiac myocytes may potentially explain why certain pain relievers that can block TRPA1 activation, such as cyclooxygenase-2 inhibitors or some nonsteroidal antiinflammatory drugs, could be associated with cardiovascular risk.

scholarly journals Overexpression of TIMP3 Protects Against Cardiac Ischemia/Reperfusion Injury by Inhibiting Myocardial Apoptosis Through ROS/Mapks Pathway

2017 ◽  
Vol 44 (3) ◽  
pp. 1011-1023 ◽  
Author(s):  
Hui Liu ◽  
Xibo Jing ◽  
Aiqiao Dong ◽  
Baobao Bai ◽  
Haiyan Wang
Keyword(s):  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Tunel Staining ◽  
Ros Production ◽  
Rat Cardiomyocytes ◽  
Doxorubicin Treatment ◽  
Myocardial Apoptosis

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. Methods: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. Results: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. Conclusion: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.

scholarly journals miR-19a/b-3p promotes inflammation during cerebral ischemia/reperfusion injury via SIRT1/FoxO3/SPHK1 pathway

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Feng Zhou ◽  
Yu-Kai Wang ◽  
Cheng-Guo Zhang ◽  
Bing-Yi Wu
Keyword(s):  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Luciferase Assay ◽  
In Vivo Model ◽  
Tunel Staining

Abstract Background Stroke affects 3–4% of adults and kills numerous people each year. Recovering blood flow with minimal reperfusion-induced injury is crucial. However, the mechanisms underlying reperfusion-induced injury, particularly inflammation, are not well understood. Here, we investigated the function of miR-19a/b-3p/SIRT1/FoxO3/SPHK1 axis in ischemia/reperfusion (I/R). Methods MCAO (middle cerebral artery occlusion) reperfusion rat model was used as the in vivo model of I/R. Cultured neuronal cells subjected to OGD/R (oxygen glucose deprivation/reperfusion) were used as the in vitro model of I/R. MTT assay was used to assess cell viability and TUNEL staining was used to measure cell apoptosis. H&E staining was employed to examine cell morphology. qRT-PCR and western blot were performed to determine levels of miR-19a/b-3p, SIRT1, FoxO3, SPHK1, NF-κB p65, and cytokines like TNF-α, IL-6, and IL-1β. EMSA and ChIP were performed to validate the interaction of FoxO3 with SPHK1 promoter. Dual luciferase assay and RIP were used to verify the binding of miR-19a/b-3p with SIRT1 mRNA. Results miR-19a/b-3p, FoxO3, SPHK1, NF-κB p65, and cytokines were elevated while SIRT1 was reduced in brain tissues following MCAO/reperfusion or in cells upon OGD/R. Knockdown of SPHK1 or FoxO3 suppressed I/R-induced inflammation and cell death. Furthermore, knockdown of FoxO3 reversed the effects of SIRT1 knockdown. Inhibition of the miR-19a/b-3p suppressed inflammation and this suppression was blocked by SIRT1 knockdown. FoxO3 bound SPHK1 promoter and activated its transcription. miR-19a/b-3p directly targeted SIRT1 mRNA. Conclusion miR-19a/b-3p promotes inflammatory responses during I/R via targeting SIRT1/FoxO3/SPHK1 axis.

Abstract 34: A Human G109E Polymorphism in Inibitor-1 Compromises Cardiomyocyte Function and Induces Arrhythmias

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Kobra Haghighi ◽  
Tracy J Pritchard ◽  
Vivek P Singh ◽  
Parthib Das ◽  
Erica L Vanderbilt ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Stress Conditions ◽  
Rat Cardiomyocytes ◽  
Promising Therapeutic Target ◽  
Endogenous Protein ◽  
Heart Failure Progression ◽  
Underlying Mechanisms

Protein phosphatase 1 (PP1) has emerged as a nodal regulator of function and survival in the heart. Indeed, the increased activity of this enzyme in failing hearts contributes to depressed SR Ca-cycling and deteriorative remodeling. PP1 is negatively regulated by endogenous inhibitor-1, which is considered a promising therapeutic target. Increases in inhibitor-1 activity and decreases in PP1 protect against ischemia/reperfusion injury, chronic isoproterenol stimulation and heart failure progression. We recently identified a polymorphism (G109E) in the inhibitor-1 gene in heart failure patients with a frequency of 6%. Expression of G109E (called mutant) in rat cardiomyocytes resulted in ~20% decreases in contractile parameters, Ca-transients and sarcoplasmic reticulum Ca-load. This depressed function was rescued by isoproterenol. Interestingly, when subjected to stress conditions (2 Hz +/- Iso), the mutant cells were more susceptible to aftercontractions. Similar findings were obtained by expression of G109E in inhibitor-1 knockout cardiomyocytes in the absence of endogenous protein. The underlying mechanisms included reduced binding of mutant to PP1, increased PP1 activity and hyper-phosphorylation of S2814 in ryanodine receptor (RyR), promoting aberrant SR Ca-release. These findings were also reflected by in vivo cardiac overexpression of G109E. Contractile and Ca-kinetic parameters were depressed by ~30% in mutant cardiomyocytes, while isoproterenol relieved these inhibitory effects. Stress conditions were associated with induction of Ca waves and aftercontractions in G109E cells. Furthermore, serial caffeine/Iso injections in vivo, elicited higher incidence of ventricular ectopy (bigeminy, trigeminy and non-sustained ventricular tachycardia) in mutant mice, whereas WTs had normal rhythm. Our findings suggest that G109E and increased PP1 may dephosphorylate the RyR and promote Ca-leak, in agreement with previous reports. Subsequently, the increased Ca-levels activate CAMK, leading to hyperphosphorylation of RyR and further increases in Ca-leak. Thus, inhibitor-1 is critical in cardiac function and represents a key control in balancing phosphatase/kinase activities to stabilize Ca-cycling in the heart.

Abstract 13914: Ischemic Preconditioning Induces MG53 Secretion From the Heart Through H 2 O 2 /PKC-delta Signaling

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Dan Shan ◽  
Yan Zhang ◽  
Rui-ping Xiao
Keyword(s):  
Ischemic Preconditioning ◽  
Cell Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Embryonic Stem ◽  
Underlying Mechanism ◽  
Neonatal Rat ◽  
Control Group ◽  
Systemic Delivery

Introduction: Ischemic heart disease is the leading cause of morbidity and mortality worldwide. Ischemic preconditioning (IPC) is the most powerful intrinsic protection against cardiac ischemia/reperfusion (I/R) injury. Previous studies have shown that a multifunctional TRIM family protein, MG53 (or TRIM72), not only plays an essential role in IPC-mediated cardioprotection, but also as a myokine/cardiokine, can be secreted from the heart and skeletal muscle in response to metabolic stress in addition to its intracellular actions. Hypothesis: We hypothesized that IPC-mediated cardioprotection is causally related to MG53 secretion and figured out the underlying mechanism. Methods and Results: Using proteomic analysis in conjunction with genetic and pharmacological approaches, we examined MG53 secretion in response to IPC and explored the underlying mechanism using rodents in in vivo , isolated perfused hearts, and cultured neonatal rat ventricular cardiomyocytes. IPC profoundly increased perfusate MG53 levels in mouse hearts by 5.50 ± 0.32 and 4.26 ± 0.40 folds from baseline over 0-60 and 60-120 min of reperfusion, respectively. Mechanistically, IPC-induced MG53 secretion is dependent on H 2 O 2 -evoked, Src-mediated phosphorylation of PKC-δ-Y311. Functionally, systemic delivery of recombinant human MG53 proteins (rhMG53) to mimic elevated circulating MG53 not only restored IPC function in MG53-deficient mice, but also protected rodent hearts from I/R injury even in the absence of IPC. Treatment of rhMG53 overtly decreased the infarct size (IF/AAR) induced by I/R compared to the BSA-treated control group (11.9 ± 1.8% vs 27.3 ± 2.0%, P <0.01), and reduced the mortality from 44.7% to 5.3% in rats. Moreover, H 2 O 2 augmented MG53 secretion, and MG53 knockdown exacerbated H 2 O 2 -induced cell injury in human embryonic stem cell-derived cardiomyocytes. Conclusions: In conclusion, IPC and oxidative stress can trigger MG53 secretion from the heart via an H 2 O 2 -PKC-δ-dependent mechanism, and secreted MG53 acts as an essential factor conveying IPC-induced cardioprotection against ischemia/reperfusion injury. Recombinant MG53 proteins can be developed into a novel treatment for various diseases of human heart in which the endogenous MG53 is low.

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