Abstract P311: Blocking Succinate Release Enhances Mitochondrial Reactive Oxygen Species Generation And Worsens Ischemia-reperfusion Injury

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Alexander S Milliken ◽  
Sergiy M Nadtochiy ◽  
Paul S Brookes
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen Species Generation ◽  
Ros Generation ◽  
Ros Production ◽  
Succinate Oxidation ◽  
Fluorescence Measurements ◽  
Mitochondrial Ros ◽  
The Impact ◽  
Infarction Heart

Succinate is a metabolite that plays a central role in ischemia-reperfusion (IR) injury,which is relevant to myocardial infarction (heart attack) and stroke. Succinateaccumulates during ischemia and is rapidly consumed at reperfusion driving reactiveoxygen species (ROS) generation at complex-I (Cx-I) and III of the mitochondrial electrontransport chain. This ROS production triggers cell-death, leading to tissue necrosis.Although succinate oxidation has been extensively studied and exploited as a noveltherapeutic target, only 1/3 of the succinate accumulated in ischemia is oxidized atreperfusion, with the remaining 2/3 being released from the cell via monocarboxylatetransporter 1 (MCT1). Extracellular succinate is thought to be pro-inflammatory, and ithas been proposed that preventing succinate release may be therapeutically beneficial.To determine the impact of preventing succinate release on IR injury, we comparedfunctional recovery (i.e. rate x pressure product, RPP) and infarction (i.e. tissue necrosis)of Langendorff perfused mouse hearts treated with an MCT1 inhibitor, AR-C155858,versus vehicle control. This revealed that succinate retention worsens IR injury (i.e.increased infarction and decreased functional recovery) likely due to increased ROS. Totest this hypothesis, we utilized a Langendorff apparatus positioned within aspectrofluorimeter, which permits real-time fluorescence measurements in beatingmouse hearts. Using the mitochondria targeted superoxide probe, MitoSOX red tomeasure ROS production at reperfusion + AR-C155858, demonstrated that succinateretention leads to enhanced mitochondrial ROS generation at the onset of reperfusion.Overall, these results suggest that inhibiting succinate release in the context of IR injurymay not be a viable therapeutic approach, regardless of any downstream anti-inflammatory effects.

Exercise training decreases rat heart mitochondria free radical generation but does not prevent Ca2+-induced dysfunction

2007 ◽  
Vol 102 (5) ◽  
pp. 1793-1798 ◽  
Author(s):  
Joseph W. Starnes ◽  
Brian D. Barnes ◽  
Marissa E. Olsen
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Electron Flow ◽  
Respiratory Control ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Calcium Overload ◽  
Ros Generation ◽  
Ros Production ◽  
Ptp Opening

Exercise provides cardioprotection against ischemia-reperfusion injury, a process involving mitochondrial reactive oxygen species (ROS) generation and calcium overload. This study tested the hypotheses that isolated mitochondria from hearts of endurance-trained rats have decreased ROS production and improved tolerance against Ca2+-induced dysfunction. Male Fischer 344 rats were either sedentary (Sed, n = 8) or endurance exercise trained (ET, n = 11) by running on a treadmill for 16 wk (5 days/wk, 60 min/day, 25 m/min, 6° grade). Mitochondrial oxidative phosphorylation measures were determined with glutamate-malate or succinate as substrates, and H2O2 production and permeability transition pore (PTP) opening were determined with succinate. All assays were carried out in the absence and presence of calcium. In response to 25 and 50 μM CaCl2, Sed and ET displayed similar decreases in state 3 respiration, respiratory control ratio, and ADP:O ratio. Ca2+-induced PTP opening was also similar. However, H2O2 production by ET was lower than Sed ( P < 0.05) in the absence of calcium (323 ± 12 vs. 362 ± 11 pmol·min−1·mg protein−1) and the presence of 50 μM CaCl2 (154 ± 3 vs. 197 ± 7 pmol·min−1·mg protein−1). Rotenone, which blocks electron flow from succinate to complex 1, reduced H2O2 production and eliminated differences between ET and Sed. Mitochondrial superoxide dismutase and glutathione peroxidase were not affected by exercise. Catalase activity was extremely low but increased 49% in ET ( P < 0.05). In conclusion, exercise reduces ROS production in myocardial mitochondria through adaptations specific to complex 1 but does not improve mitochondrial tolerance to calcium overload.

scholarly journals ZP2495 Protects against Myocardial Ischemia/Reperfusion Injury in Diabetic Mice through Improvement of Cardiac Metabolism and Mitochondrial Function: The Possible Involvement of AMPK-FoxO3a Signal Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Shuang Li ◽  
Hao Wu ◽  
Dong Han ◽  
Mingming Zhang ◽  
Na Li ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Cardiac Function ◽  
Mitochondrial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Ros Generation ◽  
Mitochondrial Morphology ◽  
Signal Pathways ◽  
The Impact

Coronary heart disease patients with type 2 diabetes were subject to higher vulnerability for cardiac ischemia-reperfusion (I/R) injury. This study was designed to evaluate the impact of ZP2495 (a glucagon-GLP-1 dual-agonist) on cardiac function and energy metabolism after myocardial I/R injury in db/db mice with a focus on mitochondrial function. C57BLKS/J-lepr+/lepr+ (BKS) and db/db mice received 4-week treatment of glucagon, ZP131 (GLP-1 receptor agonist), or ZP2495, followed by cardiac I/R injury. The results showed that cardiac function, cardiac glucose metabolism, cardiomyocyte apoptosis, cardiac mitochondrial morphology, and energetic transition were improved or ameliorated by ZP2495 to a greater extent than that of glucagon and ZP131. In vitro study showed that ZP2495, rather than glucagon, alleviated mitochondrial depolarization, cytochrome C release, and mitochondria ROS generation in neonatal rat ventricular myocytes subjected to high-glucose and simulated I/R injury conditions, the effects of which were weaker in the ZP131 group. Furthermore, the expressions of Akt, FoxO3a, and AMPK phosphorylation were elevated by ZP2495 to a greater extent than that of ZP131. In conclusion, ZP2495 may contribute to the improvement of cardiac function and energy metabolism in db/db mice after myocardial I/R injury by improving mitochondrial function possibly through Akt/FoxO3a and AMPK/FoxO3a signal pathways.

Mitochondrial ROS production during ischemia-reperfusion injury

2020 ◽  
pp. 513-538 ◽  
Author(s):  
Hiran A. Prag ◽  
Duvaraka Kula-Alwar ◽  
Timothy E. Beach ◽  
Anja V. Gruszczyk ◽  
Nils Burger ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Production ◽  
Mitochondrial Ros

scholarly journals Brain-Specific Serine-47 Modification of Cytochrome c Regulates Cytochrome c Oxidase Activity Attenuating ROS Production and Cell Death: Implications for Ischemia/Reperfusion Injury and Akt Signaling

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1843 ◽  
Author(s):  
Hasini A. Kalpage ◽  
Junmei Wan ◽  
Paul T. Morse ◽  
Icksoo Lee ◽  
Maik Hüttemann
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Reperfusion Injury ◽  
Cell Line ◽  
Cytochrome C Oxidase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Generation ◽  
Ros Production ◽  
The Brain

We previously reported that serine-47 (S47) phosphorylation of cytochrome c (Cytc) in the brain results in lower cytochrome c oxidase (COX) activity and caspase-3 activity in vitro. We here analyze the effect of S47 modification in fibroblast cell lines stably expressing S47E phosphomimetic Cytc, unphosphorylated WT, or S47A Cytc. Our results show that S47E Cytc results in partial inhibition of mitochondrial respiration corresponding with lower mitochondrial membrane potentials (ΔΨm) and reduced reactive oxygen species (ROS) production. When exposed to an oxygen-glucose deprivation/reoxygenation (OGD/R) model simulating ischemia/reperfusion injury, the Cytc S47E phosphomimetic cell line showed minimal ROS generation compared to the unphosphorylated WT Cytc cell line that generated high levels of ROS upon reoxygenation. Consequently, the S47E Cytc cell line also resulted in significantly lower cell death upon exposure to OGD/R, confirming the cytoprotective role of S47 phosphorylation of Cytc. S47E Cytc also resulted in lower cell death upon H2O2 treatment. Finally, we propose that pro-survival kinase Akt (protein kinase B) is a likely mediator of the S47 phosphorylation of Cytc in the brain. Akt inhibitor wortmannin abolished S47 phosphorylation of Cytc, while the Akt activator SC79 maintained S47 phosphorylation of Cytc. Overall, our results suggest that loss of S47 phosphorylation of Cytc during brain ischemia drives reperfusion injury through maximal electron transport chain flux, ΔΨm hyperpolarization, and ROS-triggered cell death.

scholarly journals Circular RNA TTC3 regulates cerebral ischemia-reperfusion injury and neural stem cells by miR-372-3p/TLR4 axis in cerebral infarction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo Yang ◽  
Li’e Zang ◽  
Jingwen Cui ◽  
Linlin Wei
Keyword(s):  
Stem Cells ◽  
Cerebral Ischemia ◽  
Cerebral Infarction ◽  
Neural Stem Cells ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Cerebral Ischemia Reperfusion ◽  
The Impact

Abstract Background Stroke serves as a prevalent cerebrovascular disorder with severe cerebral ischemia/reperfusion (CIR) injury, in which neural stem cells (NSCs) play critical roles in the recovery of cerebral function. Circular RNAs (circRNAs) have been widely found to participate in stroke and NSC modulation. However, the role of circRNA TTC3 (circTTC3) in the regulation of CIR injury and NSCs remains elusive. Here, we aimed to explore the impact of circTTC3 on CIR injury and NSCs. Methods The middle cerebral artery occlusion/repression (MCAO/R) model was established in C57BL/6J mice. The primary astrocytes were isolated from the cerebellum from C57BL/6J mice. The primary NSCs were obtained from rat embryos. The effect of circTTC3 on CIR injury and NSCs was analyzed by TTC staining, qPCR, Western blot, LDH colorimetric kits, MTT assays, Annexin V-FITC Apoptosis Detection Kit, luciferase reporter gene assays, and others in the system. Results Significantly, the expression of circTTC3 was elevated in the MCAO/R mice and oxygen and glucose deprivation (OGD)-treated astrocytes. The depletion of circTTC3 attenuated cerebral infarction, neurological score, and brain water content. The OGD treatment induced apoptosis and the levels of lactate dehydrogenase (LDH) in the astrocytes, in which circTTC3 depletion reduced this phenotype in the system. Moreover, the depletion of circTTC3 promoted the proliferation and upregulated the nestin and β-tubulin III expression in NSCs. Mechanically, circTTC3 was able to sponge miR-372-3p, and miR-372-3p can target Toll-like receptor 4 (TLR4) in NSCs. The miR-372-3p inhibitor or TLR4 overexpression could reverse circTTC3 depletion-mediated astrocyte OGD injury and NSC regulation. Conclusion Thus, we conclude that circTTC3 regulates CIR injury and NSCs by the miR-372-3p/TLR4 axis in cerebral infarction. Our finding presents new insight into the mechanism by which circTTC3 modulates CIR injury and NSC dysfunction. CircTTC3, miR-372-3p, and TLR4 may serve as potential targets for the treatment of CIR injury during stroke.

Decline of contractility during ischemia-reperfusion injury: actin glutathionylation and its effect on allosteric interaction with tropomyosin

2006 ◽  
Vol 290 (3) ◽  
pp. C719-C727 ◽  
Author(s):  
Frank C. Chen ◽  
Ozgur Ogut
Keyword(s):  
Reperfusion Injury ◽  
Posttranslational Modifications ◽  
Actin Polymerization ◽  
Time Course ◽  
Troponin I ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
High Concentration ◽  
Cross Sectional ◽  
The Impact

The severity and duration of ischemia-reperfusion injury is hypothesized to play an important role in the ability of the heart subsequently to recover contractility. Permeabilized trabeculae were prepared from a rat model of ischemia-reperfusion injury to examine the impact on force generation. Compared with the control perfused condition, the maximum force (Fmax) per cross-sectional area and the rate of tension redevelopment of Ca2+-activated trabeculae fell by 71% and 44%, respectively, during ischemia despite the availability of a high concentration of ATP. The reduction in Fmax with ischemia was accompanied by a decline in fiber stiffness, implying a drop in the absolute number of attached cross bridges. However, the declines during ischemia were largely recovered after reperfusion, leading to the hypothesis that intrinsic, reversible posttranslational modifications to proteins of the contractile filaments occur during ischemia-reperfusion injury. Examination of thin-filament proteins from ischemic or ischemia-reperfused hearts did not reveal proteolysis of troponin I or T. However, actin was found to be glutathionylated with ischemia. Light-scattering experiments demonstrated that glutathionylated G-actin did not polymerize as efficiently as native G-actin. Although tropomyosin accelerated the time course of native and glutathionylated G-actin polymerization, the polymerization of glutathionylated G-actin still lagged native G-actin at all concentrations of tropomyosin tested. Furthermore, cosedimentation experiments demonstrated that tropomyosin bound glutathionylated F-actin with significantly reduced cooperativity. Therefore, glutathionylated actin may be a novel contributor to the diverse set of posttranslational modifications that define the function of the contractile filaments during ischemia-reperfusion injury.

Abstract 223: The Role Of Angiogenesis In The Myocardial Ischemia/reperfusion Injury In Pregnancy

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Jingyuan li ◽  
Zoltan Pierre Arany ◽  
Mansoureh Eghbali
Keyword(s):  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Angiogenic Factor ◽  
Daily Injection ◽  
Rate Pressure Product ◽  
Ctrl Group ◽  
The Impact ◽  
In Pregnancy

Angiogenesis plays an important role in the pathogenesis of cardiovascular disease. Pro-angiogenic and anti-angiogenic treatments have provided new insights into the impact of angiogenesis-based approaches on coronary artery disease. We have recently reported that the hearts of late pregnant (LP) mice are more prone to ischemia/reperfusion (I/R) injury compared to non pregnant(NP) mice. Provided the significant change of angiogenesis status in pregnancy, here we explored whether stimulating the angiogenesis with VEGF is able to protect the heart against I/R injury in late pregnancy, and whether anti-antigenic treatment with soluble endoglin(sENG), an anti-angiogenic factor, aggravates cardiac I/R injury in NP. Pregnant mice at day 12 either received daily injection of VEGF (100 ug/kg daily subcutaneous injection) or PBS(LP CTRL) for 7 days, and at day 19 the LP mice hearts were subjected to 20 min ischemia followed by 40 min reperfusion in Langendorff. NP mice either received a single adenovirus sENG(2х10 8particles via tail vein injection) or vehicle(NP CTRL), and 10 days later NP mice were subjected to 20 min ischemia followed by 40 min reperfusion in Langendorff. The heart function was recorded throughout the experiments, and the infarct size was measured by TTC staining at the end of experiments. Exogenous VEGF treatment significantly improved the cardiac function of LP mice after ischemia. The rate pressure product (RPP) at the end of reperfusion was improved from 1617±287 mmHg*beats/min (n=6) in LP CTRL to 11287±1783 mmHg*beats/min (n=3) in the VEGF group(p<0.01). The infarct size was also significantly reduced by VEGF treatment to 25.0±4.3% (n=3) from 57.4±5.2%(n=6) in CTRL (p<0.01). While sENG aggravated the cardiac I/R injury in NP, as the RPP at the end of reperfusion in the sENG group (4523±1281 mmHg*beats/min, n=4) was significantly lower compared with NP CTRL group(12818±1213 mmHg*beats/min, n=6)(p<0.01). Furthermore, the infarct size in the sENG group was markedly higher compared with NP CTRL group (34.0±3.3% (n=4) vs. 16.3±1.4%(n=6) in NP CTRL, p<0.05). In conclusion, anti-angiogenic treatment aggravates the cardiac I/R injury in NP, while angiogenic therapy protects the heart against I/R injury in LP.

scholarly journals Transient Receptor Potential Melastatin 2 Negatively Regulates LPS-ATP-Induced Caspase-1-Dependent Pyroptosis of Bone Marrow-Derived Macrophage by Modulating ROS Production

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Haihong Wang ◽  
Xinyi Zhou ◽  
Hui Li ◽  
Xiaowei Qian ◽  
Yan Wang ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Morphological Characteristics ◽  
Receptor Potential ◽  
Ros Production ◽  
Caspase 1 ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Background. Pyroptosis, a new form of cell death, which has special morphological characteristics, depends on caspase-1 activation and occupies an important role in inflammatory immune diseases and ischemia-reperfusion injury. ROS is a common activator of NLR/caspase-1. Transient receptor potential melastatin 2 (TRPM2), a selective cation channel, is involved in inflammatory regulation. This study was designed to explore the role of TRPM2 in activating caspase-1 and caspase-1-dependent pyroptosis of mouse BMDMs. Methods. BMDMs isolated from WT and TRPM2−/− mice were treated with LPS and ATP, along with ROS inhibitor (NAC and DPI), caspase-1 inhibitor (Z-YVAD), or not. The activation of caspase-1 was measured by western blot. EtBr and EthD-2 staining were used to assess the incidence of pyroptosis. Results. Compared with WT, the activated caspase-1-P10 was higher and the percentage of EtBr positive cells was also increased in TRPM2−/− group, which were both inhibited by Z-YVAD, NAC, or DPI. ASC oligomerization was increased in TRPM2−/− group. Conclusion. Deletion of TRPM2 can enhance the activation of caspase-1 and pyroptosis, which may be via modulating ROS production, suggesting that TRPM2 plays a critical role in immune adjustment.

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