scholarly journals Myocardial MMP-2 contributes to SERCA2a proteolysis during cardiac ischaemia–reperfusion injury

2019 ◽  
Author(s):  
Andrej Roczkowsky ◽  
Brandon Y H Chan ◽  
Tim Y T Lee ◽  
Zabed Mahmud ◽  
Bridgette Hartley ◽  
...  
Keyword(s):  
Muscle Relaxation ◽  
Matrix Metalloproteinase 2 ◽  
Contractile Dysfunction ◽  
Ischaemia Reperfusion Injury ◽  
Cardiac Contractile ◽  
Ischaemia Reperfusion ◽  
Rat Hearts ◽  
Cardiac Contractile Dysfunction ◽  
Isolated Rat

Abstract Aims Matrix metalloproteinase-2 (MMP-2) is a zinc-dependent protease which contributes to cardiac contractile dysfunction when activated during myocardial ischaemia–reperfusion (IR) injury. MMP-2 is localized to several subcellular sites inside cardiac myocytes; however, its role in the sarcoplasmic reticulum (SR) is unknown. The Ca2+ ATPase SERCA2a, which pumps cytosolic Ca2+ into the SR to facilitate muscle relaxation, is degraded in cardiac IR injury; however, the protease responsible for this is unclear. We hypothesized that MMP-2 contributes to cardiac contractile dysfunction by proteolyzing SERCA2a, thereby impairing its activity in IR injury. Methods and results Isolated rat hearts were subjected to IR injury in the presence or absence of the selective MMP inhibitor ARP-100, or perfused aerobically as a control. Inhibition of MMP activity with ARP-100 significantly improved the recovery of cardiac mechanical function and prevented the increase of a 70 kDa SERCA2a degradation fragment following IR injury, although 110 kDa SERCA2a and phospholamban levels appeared unchanged. Electrophoresis of IR heart samples followed by LC-MS/MS confirmed the presence of a SERCA2a fragment of ∼70 kDa. MMP-2 activity co-purified with SR-enriched microsomes prepared from the isolated rat hearts. Endogenous SERCA2a in SR-enriched microsomes was proteolyzed to ∼70 kDa products when incubated in vitro with exogenous MMP-2. MMP-2 also cleaved purified porcine SERCA2a in vitro. SERCA activity in SR-enriched microsomes was decreased by IR injury; however, this was not prevented with ARP-100. Conclusion This study shows that MMP-2 activity is found in SR-enriched microsomes from heart muscle and that SERCA2a is proteolyzed by MMP-2. The cardioprotective actions of MMP inhibition in myocardial IR injury may include the prevention of SERCA2a degradation.

scholarly journals Detecting Validated Intracellular ROS Generation with 18F-dihydroethidine-Based PET

2021 ◽  
Author(s):  
Edward C. T. Waters ◽  
Friedrich Baark ◽  
Zilin Yu ◽  
Filipa Mota ◽  
Thomas R. Eykyn ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Contractile Function ◽  
Ex Vivo ◽  
Glutathione Depletion ◽  
Ros Generation ◽  
Cardiac Contractile ◽  
Rat Hearts ◽  
Intracellular Ros ◽  
Cardiac Contractile Dysfunction

Abstract Purpose To determine the sensitivity of the 18F-radiolabelled dihydroethidine analogue ([18F]DHE) to ROS in a validated ex vivo model of tissue oxidative stress. Procedures The sensitivity of [18F]DHE to various ROS-generating systems was first established in vitro. Then, isolated rat hearts were perfused under constant flow, with contractile function monitored by intraventricular balloon. Cardiac uptake of infused [18F]DHE (50–150 kBq.min−1) was monitored by γ-detection, while ROS generation was invoked by menadione infusion (0, 10, or 50 μm), validated by parallel measures of cardiac oxidative stress. Results [18F]DHE was most sensitive to oxidation by superoxide and hydroxyl radicals. Normalised [18F]DHE uptake was significantly greater in menadione-treated hearts (1.44 ± 0.27) versus control (0.81 ± 0.07) (p < 0.05, n = 4/group), associated with concomitant cardiac contractile dysfunction, glutathione depletion, and PKG1α dimerisation. Conclusion [18F]DHE reports on ROS in a validated model of oxidative stress where perfusion (and tracer delivery) is unlikely to impact its pharmacokinetics.

scholarly journals Matrix Metalloproteinase-2 Inhibition in Acute Ischemia-Reperfusion Heart Injury—Cardioprotective Properties of Carvedilol

2021 ◽  
Vol 14 (12) ◽  
pp. 1276
Author(s):  
Monika Skrzypiec-Spring ◽  
Joanna Urbaniak ◽  
Agnieszka Sapa-Wojciechowska ◽  
Jadwiga Pietkiewicz ◽  
Alina Orda ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Troponin I ◽  
Ischemia Reperfusion ◽  
Matrix Metalloproteinase 2 ◽  
Acute Ischemia ◽  
Mechanical Function ◽  
Cardiac Contractile ◽  
Injury Group ◽  
Rat Hearts ◽  
Cardiac Contractile Dysfunction

Matrix metalloproteinase 2 (MMP-2) is activated in hearts upon ischemia-reperfusion (IR) injury and cleaves sarcomeric proteins. It was shown that carvedilol and nebivolol reduced the activity of different MMPs. Hence, we hypothesized that they could reduce MMPs activation in myocytes, and therefore, protect against cardiac contractile dysfunction related with IR injury. Isolated rat hearts were subjected to either control aerobic perfusion or IR injury: 25 min of aerobic perfusion, followed by 20 min global, no-flow ischemia, and reperfusion for 30 min. The effects of carvedilol, nebivolol, or metoprolol were evaluated in hearts subjected to IR injury. Cardiac mechanical function and MMP-2 activity in the heart homogenates and coronary effluent were assessed along with troponin I content in the former. Only carvedilol improved the recovery of mechanical function at the end of reperfusion compared to IR injury hearts. IR injury induced the activation and release of MMP-2 into the coronary effluent during reperfusion. MMP-2 activity in the coronary effluent increased in the IR injury group and this was prevented by carvedilol. Troponin I levels decreased by 73% in IR hearts and this was abolished by carvedilol. Conclusions: These data suggest that the cardioprotective effect of carvedilol in myocardial IR injury may be mediated by inhibiting MMP-2 activation.

scholarly journals Garlic Oil Alleviates MAPKs- and IL-6-mediated Diabetes-related Cardiac Hypertrophy in STZ-induced DM Rats

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Sheng-Huang Chang ◽  
Chung-Jung Liu ◽  
Chia-Hua Kuo ◽  
Hong Chen ◽  
Wen-Yuan Lin ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Natriuretic Peptide ◽  
Contractile Function ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Contractile Dysfunction ◽  
Garlic Oil ◽  
Cardiac Contractile ◽  
Rat Hearts ◽  
Cardiac Contractile Dysfunction

Garlic oil has been reported to protect the cardiovascular system; however, the effects and mechanisms behind the cardioprotection of garlic oil on diabetes-induced cardiaomyopathy are unclear. In this study, we used streptozotocin (STZ)-induced diabetic rats to investigate whether garlic oil could protect the heart from diabetes-induced cardiomyopathy. Wistar STZ-induced diabetic rats received garlic oil (0, 10, 50 or 100 mg kg−1body weight) by gastric gavage every 2 days for 16 days. Normal rats without diabetes were used as control. Cardiac contractile dysfunction and cardiac pathologic hypertrophy responses were observed in diabetic rat hearts. Cardiac function was examined using echocardiography. In addition to cardiac hypertrophy-related mitogen-activated protein kinases (MAPK) pathways (e.g., p38, c-Jun N-terminal kinases (JNK) and extracellularly responsive kinase (ERK1/2)), the IL-6/MEK5/ERK5 signaling pathway was greatly activated in the diabetic rat hearts, which contributes to the up-regulation of cardiac pathologic hypertrophy markers including atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), and leads to cardiac contractile dysfunction. Garlic oil treatment significantly inhibited the up-regulation in MAPK (e.g., p38, JNK and ERK1/2) and IL-6/MEK5/ERK5 signaling pathways in the diabetic rat hearts, reducing the levels of cardiac pathologic hypertrophy markers such as ANP and BNP, and improving the cardiac contractile function. Collectively, data from these studies demonstrate that garlic oil shows the potential cardioprotective effects for protecting heart from diabetic cardiomyopathy.

scholarly journals Novel roles of an intragenic G-quadruplex in controlling microRNA expression and cardiac function

2021 ◽  
Author(s):  
Min Zhu ◽  
Juan Gao ◽  
Xian-Juan Lin ◽  
Yun-Yun Gong ◽  
Yan-Chao Qi ◽  
...  
Keyword(s):  
Heart Function ◽  
Contractile Dysfunction ◽  
Normal Heart ◽  
Cardiac Contractile ◽  
G Quadruplex ◽  
Cardiac Contractile Dysfunction ◽  
Rna Motif ◽  
Rat Genome

Abstract Simultaneous dysregulation of multiple microRNAs (miRs) affects various pathological pathways related to cardiac failure. In addition to being potential cardiac disease-specific markers, miR-23b/27b/24-1 were reported to be responsible for conferring cardiac pathophysiological processes. In this study, we identified a conserved guanine-rich RNA motif within the miR-23b/27b/24-1 cluster that can form an RNA G-quadruplex (rG4) in vitro and in cells. Disruption of this intragenic rG4 significantly increased the production of all three miRs. Conversely, a G4-binding ligand tetrandrine (TET) stabilized the rG4 and suppressed miRs production in human and rodent cardiomyocytes. Our further study showed that the rG4 prevented Drosha-DGCR8 binding and processing of the pri-miR, suppressing the biogenesis of all three miRs. Moreover, CRISPR/Cas9-mediated G4 deletion in the rat genome aberrantly elevated all three miRs in the heart in vivo, leading to cardiac contractile dysfunction. Importantly, loss of the G4 resulted in reduced targets for the aforementioned miRs critical for normal heart function and defects in the L-type Ca2+ channel-ryanodine receptor (LCC-RyR) coupling in cardiomyocytes. Our results reveal a novel mechanism for G4-dependent regulation of miR biogenesis, which is essential for maintaining normal heart function.

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