scholarly journals Matrix metalloproteinase-2 in oncostatin M-induced sarcomere degeneration in cardiomyocytes

2016 ◽  
Vol 311 (1) ◽  
pp. H183-H189 ◽  
Author(s):  
Xiaohu Fan ◽  
Bryan G. Hughes ◽  
Mohammad A. M. Ali ◽  
Brandon Y. H. Chan ◽  
Katherine Launier ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Troponin I ◽  
Ventricular Myocytes ◽  
Oncostatin M ◽  
Neonatal Rat ◽  
Matrix Metalloproteinase 2 ◽  
Mmp Inhibitor ◽  
Confocal Immunofluorescence ◽  
Neonatal Rat Ventricular Myocytes

Cardiomyocyte dedifferentiation may be an important source of proliferating cardiomyocytes facilitating cardiac repair. Cardiomyocyte dedifferentiation and proliferation induced by oncostatin-M (OSM) is characterized by sarcomere degeneration. However, the mechanism underlying sarcomere degeneration remains unclear. We hypothesized that this process may involve matrix metalloproteinase-2 (MMP-2), a key protease localized at the sarcomere in cardiomyocytes. We tested the hypothesis that MMP-2 is involved in the sarcomere degeneration that characterizes cardiomyocyte dedifferentiation. Confocal immunofluorescence and biochemical methods were used to explore the role of MMP-2 in OSM-induced dedifferentiation of neonatal rat ventricular myocytes (NRVM). OSM caused a concentration- and time-dependent loss of sarcomeric α-actinin and troponin-I in NRVM. Upon OSM-treatment, the mature sarcomere transformed to a phenotype resembling a less-developed sarcomere, i.e., loss of sarcomeric proteins and Z-disk transformed into disconnected Z bodies, characteristic of immature myofibrils. OSM dose dependently increased MMP-2 activity. Both the pan-MMP inhibitor GM6001 and the selective MMP-2 inhibitor ARP 100 prevented sarcomere degeneration induced by OSM treatment. OSM also induced NRVM cell cycling and increased methyl-thiazolyl-tetrazolium (MTT) staining, preventable by MMP inhibition. These results suggest that MMP-2 mediates sarcomere degeneration in OSM-induced cardiomyocyte dedifferentiation and thus potentially contributes to cardiomyocyte regeneration.

Doxorubicin induces de novo expression of N-terminal-truncated matrix metalloproteinase-2 in cardiac myocytes

2018 ◽  
Vol 96 (12) ◽  
pp. 1238-1245 ◽  
Author(s):  
Brandon Y.H. Chan ◽  
Andrej Roczkowsky ◽  
Nils Moser ◽  
Mathieu Poirier ◽  
Bryan G. Hughes ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Matrix Metalloproteinase ◽  
Troponin I ◽  
De Novo ◽  
Ventricular Myocytes ◽  
Cardiac Injury ◽  
Full Length ◽  
Neonatal Rat ◽  
Matrix Metalloproteinase 2 ◽  
Independent Manner

Anthracyclines, such as doxorubicin, are commonly prescribed antineoplastic agents that cause irreversible cardiac injury. Doxorubicin cardiotoxicity is initiated by increased oxidative stress in cardiomyocytes. Oxidative stress enhances intracellular matrix metalloproteinase-2 (MMP-2) by direct activation of its full-length isoform and (or) de novo expression of an N-terminal-truncated isoform (NTT-MMP-2). As MMP-2 is localized to the sarcomere, we tested whether doxorubicin activates intracellular MMP-2 in neonatal rat ventricular myocytes (NRVM) and whether it thereby proteolyzes two of its identified sarcomeric targets, α-actinin and troponin I. Doxorubicin increased oxidative stress within 12 h as indicated by reduced aconitase activity. This was associated with a twofold increase in MMP-2 protein levels and threefold higher gelatinolytic activity. MMP inhibitors ARP-100 or ONO-4817 (1 μM) prevented doxorubicin-induced MMP-2 activation. Doxorubicin also increased the levels and activity of MMP-2 secreted into the conditioned media. Doxorubicin upregulated the mRNA expression of both full-length MMP-2 and NTT-MMP-2. α-Actinin levels remained unchanged, whereas doxorubicin downregulated troponin I in an MMP-independent manner. Doxorubicin induces oxidative stress and stimulates a robust increase in MMP-2 expression and activity in NRVM, including NTT-MMP-2. The sarcomeric proteins α-actinin and troponin I are, however, not targeted by MMP-2 under these conditions.

Cytochrome P-450 metabolites in endothelin-stimulated cardiac hormone secretion

2004 ◽  
Vol 286 (5) ◽  
pp. R888-R893 ◽  
Author(s):  
Sook Jeong Lee ◽  
Carol S. Landon ◽  
Stanley J. Nazian ◽  
John R. Dietz
Keyword(s):  
Protein Kinase ◽  
Inhibitory Action ◽  
Ventricular Myocytes ◽  
Hormone Secretion ◽  
Neonatal Rat ◽  
Kinase C ◽  
Neonatal Rat Ventricular Myocytes ◽  
Cytochrome P 450 ◽  
Kinase A

We examined the role of cytochrome P-450-arachidonate (CYP450-AA) metabolites in endothelin-1 (ET-1)-stimulated atrial natriuretic peptide (ANP) and pro-ANP-(1-30) secretion from the heart. 17-Octadecynoic acid (17-ODYA, 10-5 M) significantly inhibited ANP secretion stimulated by ET-1 (10-8 M) in the isolated perfused rat atria and inhibited pro-ANP-(1-30) secretion stimulated by ET-1 (10-8 M) or 20-hydroxyeicosatetraenoic acid in cultured neonatal rat ventricular myocytes (NRVM). In NRVM, 17-ODYA significantly ( P < 0.05) increased secretion of cAMP but had no significant effect on the secretion of cGMP from NRVM. Staurosporine, an inhibitor of protein kinase C, completely blocked the inhibitory action of 17-ODYA, whereas a protein kinase A inhibitor, H-89 (5 × 10-5 M), did not significantly attenuate the effects of 17-ODYA. The results show that the inhibitory action of 17-ODYA on ET-1-augmented ANP secretion is mediated through cAMP and suggest that CYP450-AA may play an important role in ET-1-induced cardiac hormone secretion.

scholarly journals Nitric oxide-induced cardioprotection in cultured rat ventricular myocytes

2000 ◽  
Vol 278 (4) ◽  
pp. H1211-H1217 ◽  
Author(s):  
Roby D. Rakhit ◽  
Richard J. Edwards ◽  
James W. Mockridge ◽  
Anwar R. Baydoun ◽  
Amanda W. Wyatt ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ventricular Myocytes ◽  
Culture Conditions ◽  
Neonatal Rat ◽  
No Donor ◽  
Rat Ventricular Myocytes ◽  
Kinase C ◽  
Neonatal Rat Ventricular Myocytes ◽  
Oxide Synthase

The aim of this study was to investigate the role of nitric oxide (NO) in a cellular model of early preconditioning (PC) in cultured neonatal rat ventricular myocytes. Cardiomyocytes “preconditioned” with 90 min of stimulated ischemia (SI) followed by 30 min reoxygenation in normal culture conditions were protected against subsequent 6 h of SI. PC was blocked by N G-monomethyl-l-arginine monoacetate but not by dexamethasone pretreatment. Inducible nitric oxide synthase (NOS) protein expression was not detected during PC ischemia. Pretreatment (90 min) with the NO donor S-nitroso- N-acetyl-l,l-penicillamine (SNAP) mimicked PC, resulting in significant protection. SNAP-triggered protection was completely abolished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) but was unaffected by chelerythrine or the presence of glibenclamide and 5-hydroxydecanoate. With the use of RIA, SNAP treatment increased cGMP levels, which were blocked by ODQ. Hence, NO is implicated as a trigger in this model of early PC via activation of a constitutive NOS isoform. After exposure to SNAP, the mechanism of cardioprotection is cGMP dependent but independent of protein kinase C or ATP-sensitive K+ channels. This differs from the proposed mechanism of NO-induced cardioprotection in late PC.

Abstract 16870: Dissociation of Mitochondrial HK-II Triggers Mitochondria Specific Autophagy

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Shigeki Miyamoto ◽  
David J Roberts ◽  
Valerie P Tan-Sah
Keyword(s):  
Energy Production ◽  
Ventricular Myocytes ◽  
Neonatal Rat ◽  
Mouse Heart ◽  
Hexokinase Ii ◽  
Survival Pathway ◽  
Mitochondrial Membrane Depolarization ◽  
Neonatal Rat Ventricular Myocytes

Introduction: There is emerging evidence that the metabolic pathway interplays with the survival pathway to preserve cellular homeostasis. Hexokinases (HKs) catalyze the first step of glucose metabolism and hexokinase-II (HK-II) is the predominant isoform in the heart. Our recent study revealed that HK-II positively regulates general autophagy in the absence of glucose. Mitochondrial HK-II (mitoHK-II) is regulated by Akt and provides cardioprotection while it is decreased in the ischemic heart. Hypothesis: We tested the hypothesis that mitoHK-II dissociation triggers mitochondria specific autophagy (mitophagy). Results: As previously reported, mitoHK-II levels were decreased by ~40% in the perfused mouse heart subjected to global ischemia and in neonatal rat ventricular myocytes (NRVMs) subjected to simulated ischemia. To assess the role of mitoHK-II dissociation, mitoHK-II dissociating peptide (15NG) was expressed in NRVMs. MitoHK-II was decreased by 40% in NRVMs expressing 15NG which was accompanied with Parkin translocation to mitochondria and ubiquitination of mitochondrial proteins. This response was attenuated by Parkin knockdown and reversed by the recovery of mitoHK-II by co-expression of HK-II but not by that of mitochondria binding deficient mutant. 15NG expression did not induce mitochondrial membrane depolarization nor PINK1 stabilization at mitochondria, suggesting that the effects of mitoHK-II dissociation is not dependent on the previously established mitochondria depolarization/PINK1 pathway. This was confirmed by the experiments using PINK1 siRNA. Modest dissociation of mitoHK-II (by 20%) did not induce mitophagic responses but remarkably enhanced FCCP induced mitophagy, indicating that these two pathways are synergetic. We will be analyzing 15NG transgenic mice generated in our lab to determine the mitophagic role of mitoHK-II dissociation in vivo. Conclusions: These results suggest that mitoHK-II dissociation can regulate Parkin dependent mitophagy, in conjunction with depolarization dependent mechanisms and that HK-II could confer cardioprotection by switching the cell from an energy production to an energy conservation mode under ischemia.

Abstract 307: Phospholipase Cε Is Involved in Gq-Dependent Protein Kinase D Activation in Cardiac Myocytes

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Alan Smrcka ◽  
Lianghui Zhang ◽  
Sundeep Malik
Keyword(s):  
Protein Kinase ◽  
G Proteins ◽  
Ventricular Myocytes ◽  
Neonatal Rat ◽  
Protein Kinase D ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Neonatal Rat Ventricular Myocytes ◽  
Phospholipase Cε

We previously demonstrated that PLCε is a critical mediator of endothelin-1 (ET-1)- and norepinephrine (NE)-dependent hypertrophy in neonatal rat ventricular myocytes (NRVMs). Both α-adrenergic and ET-1 receptors couple to Gq as well as other G proteins. To determine if PLCε is required for Gαq-dependent hypertrophy NRVMs were infected with adenoviruses expressing wtGαq and PLCε siRNA followed by measurement of hypertrophy. PLCε-siRNA significantly inhibited Gαq-induced increases in myocyte area and atrial natriuretic factor (ANF) mRNA expression. Similarly, disruption of PLCε association with perinuclear mAKAP inhibited Gαq-dependent hypertrophy. These data suggest that ET-1 and PE signal, at least in part, through Gαq and PLCε. To explore the functional role of PLCε in ET-1/Gq dependent hypertrophy, activation of protein kinase D (PKD) in NRVMs was assessed in response to ET-1. PLCε-siRNA significantly inhibited ET-1 induced PKD activation (∼50% inhibition). Disruption of PLCε-mAKAP interactions also significantly inhibited ET-1 induced PKD activation (∼50% inhibition). We propose that PLCε scaffolded to mAKAP at the nuclear envelope responds to Gαq-dependent, as well as other hypertrophic signals, to locally regulate PKD in a process that is critical for hypertrophy development.

scholarly journals KLF15 Regulates Oxidative Stress Response in Cardiomyocytes through NAD+

Metabolites ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 620
Author(s):  
Le Li ◽  
Weiyi Xu ◽  
Lilei Zhang
Keyword(s):  
Oxidative Stress ◽  
Ventricular Myocytes ◽  
Cardiac Metabolism ◽  
Neonatal Rat ◽  
Oxygen Species ◽  
Oxidative Stresses ◽  
Neonatal Rat Ventricular Myocytes ◽  
Rate Limiting ◽  
Defective Clearance

KLF15 has recently emerged as a central regulator of metabolism. Although its connection to oxidative stress has been suspected, there has not been any study to date that directly demonstrates the molecular link. In this study, we sought to determine the role of KLF15 in cardiac oxidative stress. We found that KLF15 deficiency in the heart is associated with increased oxidative stress. Acute deficiency of KLF15 in neonatal rat ventricular myocytes (NRVMs) leads to the defective clearance of reactive oxygen species (ROS) and an exaggerated cell death following a variety of oxidative stresses. Mechanistically, we found that KLF15 deficiency leads to reduced amounts of the rate-limiting NAD+ salvage enzyme NAMPT and to NAD+ deficiency. The resultant SIRT3-dependent hyperacetylation and the inactivation of mitochondrial antioxidants can be rescued by MnSOD mimetics or NAD+ precursors. Collectively, these findings suggest that KLF15 regulates cardiac ROS clearance through the regulation of NAD+ levels. Our findings establish KLF15 as a central coordinator of cardiac metabolism and ROS clearance.

CARP Plays a Key Role in Cellular Growth Under Hypertrophic Stimuli in Neonatal Rat Ventricular Myocytes

2013 ◽  
Vol 9 ◽  
Author(s):  
Tara A Shrout
Keyword(s):  
Gene Expression ◽  
Ventricular Myocytes ◽  
Cellular Growth ◽  
Neonatal Rat ◽  
Transcriptional Level ◽  
Dual Nature ◽  
Hypertrophic Growth ◽  
Rat Ventricular Myocytes ◽  
Neonatal Rat Ventricular Myocytes ◽  
Over Time

Cardiac hypertrophy is a growth process that occurs in response to stress stimuli or injury, and leads to the induction of several pathways to alter gene expression. Under hypertrophic stimuli, sarcomeric structure is disrupted, both as a consequence of gene expression and local changes in sarcomeric proteins. Cardiac-restricted ankyrin repeat protein (CARP) is one such protein that function both in cardiac sarcomeres and at the transcriptional level. We postulate that due to this dual nature, CARP plays a key role in maintaining the cardiac sarcomere. GATA4 is another protein detected in cardiomyocytes as important in hypertrophy, as it is activated by hypertrophic stimuli, and directly binds to DNA to alter gene expression. Results of GATA4 activation over time were inconclusive; however, the role of CARP in mediating hypertrophic growth in cardiomyocytes was clearly demonstrated. In this study, Neonatal Rat Ventricular Myocytes were used as a model to detect changes over time in CARP and GATA4 under hypertrophic stimulation by phenylephrine and high serum media. Results were detected by analysis of immunoblotting. The specific role that CARP plays in mediating cellular growth under hypertrophic stimuli was studied through immunofluorescence, which demonstrated that cardiomyocyte growth with hypertrophic stimulation was significantly blunted when NRVMs were co-treated with CARP siRNA. These data suggest that CARP plays an important role in the hypertrophic response in cardiomyocytes.

Cardiac mitofusin-1 is declined in non-responding patients with idiopathic dilated cardiomyopathy

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Hsiao ◽  
I Shimizu ◽  
T Wakasugi ◽  
S Jiao ◽  
T Watanabe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heart Failure ◽  
Ventricular Myocytes ◽  
Severe Heart Failure ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Heart Failure Patients ◽  
Underlying Mechanisms ◽  
Neonatal Rat Ventricular Myocytes ◽  
Mitofusin 1

Abstract Background/Introduction Mitochondria are dynamic regulators of cellular metabolism and homeostasis. The dysfunction of mitochondria has long been considered a major contributor to aging and age-related diseases. The prognosis of severe heart failure is still unacceptably poor and it is urgent to establish new therapies for this critical condition. Some patients with heart failure do not respond to established multidisciplinary treatment and they are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown. Purpose Studies indicate mitochondrial dysfunction has causal roles for metabolic remodeling in the failing heart, but underlying mechanisms remain to be explored. This study tried to elucidate the role of Mitofusin-1 in a failing heart. Methods We examined twenty-two heart failure patients who underwent endomyocardial biopsy of intraventricular septum. Patients were classified as non-responders when their left-ventricular (LV) ejection fraction did not show more than 10% improvement at remote phase after biopsy. Fourteen patients were classified as responders, and eight as non-responders. Electron microscopy, quantitative PCR, and immunofluorescence studies were performed to explore the biological processes or molecules involved in failure to respond. In addition to studies with cardiac tissue specific knockout mice, we also conducted functional in-vitro studies with neonatal rat ventricular myocytes. Results Twenty-two patients with IDCM who underwent endomyocardial biopsy were enrolled in this study, including 14 responders and 8 non-responders. Transmission electron microscopy (EM) showed a significant reduction in mitochondrial size in cardiomyocytes of non-responders compared to responders. Quantitative PCR revealed that transcript of mitochondrial fusion protein, Mitofusin-1, was significantly reduced in non-responders. Studies with neonatal rat ventricular myocytes (NRVMs) indicated that the beta-1 adrenergic receptor-mediated signaling pathway negatively regulates Mitofusin-1 expression. Suppression of Mitofusin-1 resulted in a significant reduction in mitochondrial respiration of NRVMs. We generated left ventricular pressure overload model with thoracic aortic constriction (TAC) in cardiac specific Mitofusin-1 knockout model (c-Mfn1 KO). Systolic function was reduced in c-Mfn1 KO mice, and EM study showed an increase in dysfunctional mitochondria in the KO group subjected to TAC. Conclusions Mitofusin-1 becomes a biomarker for non-responders with heart failure. In addition, our results suggest that therapies targeting mitochondrial dynamics and homeostasis would become next generation therapy for severe heart failure patients. Funding Acknowledgement Type of funding source: None

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