Melatonin confers cardioprotective effect against myocardial ischemia/reperfusion (MI/R) injury by reducing oxidative stress. Activation of silent information regulator 1 (SIRT1) signaling also reduces MI/R injury. We hypothesize that melatonin may protect against MI/R injury by activating SIRT1 signaling. This study investigated the protective effect of melatonin treatment on MI/R heart and elucidated its potential mechanisms. Rats were exposed to melatonin treatment in the presence or the absence of the melatonin receptor antagonist luzindole or SIRT1 inhibitor EX527 and then subjected to MI/R operation. Melatonin conferred a cardioprotective effect by improving postischemic cardiac function, decreasing infarct size, reducing apoptotic index, diminishing serum creatine kinase and lactate dehydrogenase release, upregulating SIRT1, Bcl-2 expression and downregulating Bax, caspase-3 and cleaved caspase-3 expression. Melatonin treatment also resulted in reduced myocardium superoxide generation, gp91(phox) expression, malondialdehyde level, and increased myocardium superoxide dismutase (SOD) level, which indicate that the MI/R-induced oxidative stress was significantly attenuated. However, these protective effects were blocked by EX527 or luzindole, indicating that SIRT1 signaling and melatonin receptor may be specifically involved in these effects. In summary, our results demonstrate that melatonin treatment attenuates MI/R injury by reducing oxidative stress damage via activation of SIRT1 signaling in a receptor-dependent manner.
Although silybin, a natural flavonolignan, has been shown to exhibit potent antitumor activities against various types of cancers, including lung cancer, the molecular mechanisms behind these activities remain unclear. Silent information regulator 1 (SIRT1) is a conserved NAD(+)-dependent deacetylase that has been implicated in the modulation of transcriptional silencing and cell survival. Furthermore, it plays a key role in carcinogenesis through the deacetylation of important regulatory proteins, including p53. In this study, we investigated the antitumor activity of silybin towards human lung adenocarcinoma cells in vitro and in vivo and explored the role of the SIRT1 signaling pathway in this process. Silybin treatment resulted in a dose- and time-dependent decrease in lung adenocarcinoma A549 cell viability. In addition, silybin exhibited strong antitumor activity illustrated by reductions in tumor cell adhesion, migratory capability, and glutathione levels and by increased apoptotic indices and reactive oxygen species levels. Silybin treatment also downregulated SIRT1 and upregulated p53 acetylation. SIRT1 siRNA (in vitro) or cambinol (a known SIRT1 inhibitor used for in vivo studies) further enhanced the antitumor activity of silybin. In summary, silybin is a potent inhibitor of lung adenocarcinoma cell growth that interferes with SIRT1 signaling, and this inhibition is a novel mechanism of silybin action that may be used for therapeutic intervention in lung adenocarcinoma treatment.
The pentalogy of Cantrell is a rare and fatal malformation. A left ventricular diverticulum is a common finding of this pentalogy. The present report summarizes our experience with three patients who suffered from pentalogy of Cantrell. All three cases had a left ventricular diverticulum. The intracardiac malformations and the left ventricular diverticulum were corrected simultaneously. All patients recovered uneventfully. One-stage surgical correction could improve short-term outcomes in selected patients with pentalogy of Cantrell.
Silent information regulator 1 (SIRT1) is a type of histone deacetylase whose activity is dependent on nicotinamide adenine dinucleotide. SIRT1 plays a key role in the longevity effects elicited by calorie restriction. Recently, a neuroprotective effect of SIRT1 was reported for neurological diseases. The focus of this review is to summarize the protective effects of SIRT1 in cerebral ischemia. First, the posttranslational modifications of SIRT1 are illustrated; then, we discuss the roles of SIRT1 in cerebral immune homeostasis. Next, we introduce the deacetylase activity of SIRT1 in cerebral ischemia and provide some examples of relevant studies. In addition, we discuss several activated mediators of SIRT1, such as resveratrol, caloric restriction, ischemic preconditioning, and other proteins and compounds. Finally, we highlight a few SIRT1-related signaling pathways, such as the peroxisome proliferator-activated receptor ? coactivator 1?, nuclear transcription factor ?B, uncoupling protein 2, and forkhead box O pathways. Taken together, the information compiled in this article will serve as a comprehensive reference for the actions of SIRT1 in the nervous system and will help in the design of future experimental research and promote SIRT1 as a new therapeutic target.
Ischemia reperfusion (IR) injury (IRI) is harmful to the cardiovascular system and causes mitochondrial oxidative stress. Silent information regulator 1 (SIRT1), a type of histone deacetylase, contributes to IRI. Curcumin (Cur) is a strong natural antioxidant and is the active component in Curcuma longa; Cur has protective effects against IRI and may regulate the activity of SIRT1. This study was designed to investigate the protective effect of Cur pretreatment on myocardial IRI and to elucidate this potential mechanism. Isolated and in vivo rat hearts and cultured neonatal rat cardiomyocytes were subjected to IR. Prior to this procedure, the hearts or cardiomyocytes were exposed to Cur in the absence or presence of the SIRT1 inhibitor sirtinol or SIRT1 siRNA. Cur conferred a cardioprotective effect, as shown by improved postischemic cardiac function, decreased myocardial infarct size, decreased myocardial apoptotic index, and several biochemical parameters, including the up-regulation of the antiapoptotic protein Bcl2 and the down-regulation of the proapoptotic protein Bax. Sirtinol and SIRT1 siRNA each blocked the Cur-mediated cardioprotection by inhibiting SIRT1 signaling. Cur also resulted in a well-preserved mitochondrial redox potential, significantly elevated mitochondrial superoxide dismutase activity, and decreased formation of mitochondrial hydrogen peroxide and malondialdehyde. These observations indicated that the IR-induced mitochondrial oxidative damage was remarkably attenuated. However, this Cur-elevated mitochondrial function was reversed by sirtinol or SIRT1 siRNA treatment. In summary, our results demonstrate that Cur pretreatment attenuates IRI by reducing IR-induced mitochondrial oxidative damage through the activation of SIRT1 signaling.
Ischemia/reperfusion injury (IRI) is harmful to the cardiovascular system and causes mitochondrial oxidative stress. Numerous data indicate that the JAK2/STAT3 signaling pathway is specifically involved in preventing myocardial IRI. Melatonin has potent activity against IRI and may regulate JAK2/STAT3 signaling. This study investigated the protective effect of melatonin pretreatment on myocardial IRI and elucidated its potential mechanism. Perfused isolated rat hearts and cultured neonatal rat cardiomyocytes were exposed to melatonin in the absence or presence of the JAK2/STAT3 inhibitor AG490 or JAK2 siRNA and then subjected to IR. Melatonin conferred a cardio-protective effect, as shown by improved postischemic cardiac function, decreased infarct size, reduced apoptotic index, diminished lactate dehydrogenase release, up-regulation of the anti-apoptotic protein Bcl2, and down-regulation of the pro-apoptotic protein Bax. AG490 or JAK2 siRNA blocked melatonin-mediated cardio-protection by inhibiting JAK2/STAT3 signaling. Melatonin exposure also resulted in a well-preserved mitochondrial redox potential, significantly elevated mitochondrial superoxide dismutase (SOD) activity, and decreased formation of mitochondrial hydrogen peroxide (H2 O2 ) and malondialdehyde (MDA), which indicates that the IR-induced mitochondrial oxidative damage was significantly attenuated. However, this melatonin-induced effect on mitochondrial function was reversed by AG490 or JAK2 siRNA treatment. In summary, our results demonstrate that melatonin pretreatment can attenuate IRI by reducing IR-induced mitochondrial oxidative damage via the activation of the JAK2/STAT3 signaling pathway.
Previous studies have shown that the JAK2/STAT3 signaling pathway plays a regulatory role in cellular oxidative stress injury (OSI). In this study, we explored the role of the JAK2/STAT3 signaling pathway in hydrogen peroxide (H2O2)-induced OSI and the protective effect of melatonin against (H2O2)-induced injury in human umbilical vein endothelial cells (HUVECs). AG490 (a specific inhibitor of the JAK2/STAT3 signaling pathway) and JAK2 siRNA were used to manipulate JAK2/STAT3 activity, and the results showed that AG490 and JAK2 siRNA inhibited OSI and the levels of p-JAK2 and p-STAT3. HUVECs were then subjected to H2O2 in the absence or presence of melatonin, the main secretory product of the pineal gland. Melatonin conferred a protective effect against H2O2, which was evidenced by improvements in cell viability, adhesive ability and migratory ability, decreases in the apoptotic index and reactive oxygen species (ROS) production and several biochemical parameters in HUVECs. Immunofluorescence and Western blotting showed that H2O2 treatment increased the levels of p-JAK2, p-STAT3, Cytochrome c, Bax and Caspase3 and decreased the levels of Bcl2, whereas melatonin treatment partially reversed these effects. We, for the first time, demonstrate that the inhibition of the JAK2/STAT3 signaling pathway results in a protective effect against endothelial OSI. The protective effects of melatonin against OSI, at least partially, depend upon JAK2/STAT3 inhibition.
Hepatocellular carcinoma (HCC) is a global health burden that is associated with limited treatment options and poor patient prognoses. Silybin (SIL), an antioxidant derived from the milk thistle plant (Silybum marianum), has been reported to exert hepatoprotective and antitumorigenic effects both in vitro and in vivo. While SIL has been shown to have potent antitumor activity against various types of cancer, including HCC, the molecular mechanisms underlying the effects of SIL remain largely unknown. The Notch signaling pathway plays crucial roles in tumorigenesis and immune development. In the present study, we assessed the antitumor activity of SIL in human HCC HepG2 cells in vitro and in vivo and explored the roles of the Notch pathway and of the apoptosis-related signaling pathway on the activity of SIL. SIL treatment resulted in a dose- and time-dependent inhibition of HCC cell viability. Additionally, SIL exhibited strong antitumor activity, as evidenced not only by reductions in tumor cell adhesion, migration, intracellular glutathione (GSH) levels and total antioxidant capability (T-AOC) but also by increases in the apoptotic index, caspase3 activity, and reactive oxygen species (ROS). Furthermore, SIL treatment decreased the expression of the Notch1 intracellular domain (NICD), RBP-J?, and Hes1 proteins, upregulated the apoptosis pathway-related protein Bax, and downregulated Bcl2, survivin, and cyclin D1. Notch1 siRNA (in vitro) or DAPT (a known Notch1 inhibitor, in vivo) further enhanced the antitumor activity of SIL, and recombinant Jagged1 protein (a known Notch ligand in vitro) attenuated the antitumor activity of SIL. Taken together, these data indicate that SIL is a potent inhibitor of HCC cell growth that targets the Notch signaling pathway and suggest that the inhibition of Notch signaling may be a novel therapeutic intervention for HCC.
Although pterostilbene (PTE) has been shown to have potent antitumor activities against various cancer types, the molecular mechanisms of these activities remain unclear. In this study, we investigated the antitumor activity of PTE against human lung adenocarcinoma in vitro and in vivo and explored the role of the Notch1 signaling pathway in this process. PTE treatment resulted in a dose- and time-dependent decrease in the viability of A549 cells. Additionally, PTE exhibited strong antitumor activity, as evidenced not only by a reduced mitochondrial membrane potential (MMP) and a decreased intracellular glutathione content but also by increases in the apoptotic index and the level of reactive oxygen species (ROS). Furthermore, PTE treatment induced the activation of the Notch1 Intracellular Domain (NICD) protein and activated Hes1. DAPT (a gamma secretase inhibitor) and Notch1 siRNA prevented the induction of NICD and Hes1 activation by PTE treatment and sensitized the cells to PTE treatment. The down-regulation of Notch signaling also prevented the activation of pro-survival pathways (most notably the PI3K/Akt pathway) after PTE treatment. In summary, lung adenocarcinoma cells may enhance Notch1 activation as a protective mechanism in response to PTE treatment. Combining a gamma secretase inhibitor with PTE treatment may represent a novel approach for treating lung adenocarcinoma by inhibiting the survival pathways of cancer cells.
A one-stage repair was planned for an 11-year-old boy with tetralogy of Fallot. After initial attempts to wean from cardiopulmonary bypass were unsuccessful, an atrial septal defect and a ventricular septal defect were created in order to achieve hemodynamic stability. The boy recovered from the operation but had large volume of chest drainage. Transthoracic echocardiography revealed left to right shunting at both atrial and ventricular levels. Interventional catheter-directed devices were used to repair the residual shunts successfully in the catheterization laboratory.
Adenosine pretreatment reduces injury caused by ischemia-reperfusion. To investigate the hypothesis that adenosine pretreatment would modulate injury induced by cardiopulmonary bypass (CPB) and myocardial ischemia/reperfusion, we conducted a randomized controlled trial on the effects of adenosine pretreatment in children undergoing surgery to repair congenital heart defects.
Myxomas are the most common type of primary cardiac tumors. We report our use of totally thoracoscopic surgery in resecting cardiac myxomas in 12 cases with 10 in the left atria and 2 in the right atria. Totally thoracoscopic surgical resection of myxoma was successfully performed in all cases through three minimal incisions, with the largest incision less than 3 cm. The cardiopulmonary bypass time was 96 to 126 minutes, and the aortic cross-clamp time was 46 to 63 minutes. Postoperative ventilation assistance was 3 to 11 hours. We show that the method is safe and achieves complete tumor resection.
Ischemic preconditioning (IPC) is the strongest endogenous myocardial protective mechanism, but up to now, its specific mechanisms have not been completely understood. The Notch network regulates multiple cellular processes, including cell fate determination, development, differentiation, proliferation, apoptosis, and regeneration. Recent loss-of-function studies have shown that the Notch1 receptor controls the response to injury in the adult heart by limiting myocyte hypertrophy, enhancing myocyte survival, promoting precursor proliferation and reducing interstitial fibrosis. Notch signaling also plays a regulatory role in adult cardiac injury and in protection of myocardial function after ischemia. The Notch pathway cross-talks with the PI3K/Akt and NF-?B signaling pathways, both of which are well-known factors involved in IPC-induced myocardial protection. We therefore hypothesize that Notch signaling may play a regulatory role in myocardial protection during ischemic preconditioning and hope to find new drug targets to attain the same beneficial effects of Notch signaling without ischemic insults.
The objective was to report the surgical results following failed transcatheter intervention for closure of ventricular septal defects (VSDs). This study is a retrospective analysis of patients (n = 9) from Xijing Hospital (Xian, China) with failed transcatheter intervention for VSDs who subsequently underwent open heart surgery. Five patients experienced complications during transcatheter intervention, including third-degree atrioventricular block (III° AVB) (n = 2), aortic incompetence (n = 2), or tricuspid incompetence (n = 1). The devices were immediately removed in the catheterization laboratory followed by open heart surgery to repair VSDs. Four patients experienced complications after transcatheter intervention; one patients device was displaced into the right ventricle, and 3 patients had III° AVB. These patients underwent surgery to retrieve the devices and to repair VSDs. All cardiac surgery was performed under general anesthesia and under cardiopulmonary bypass. Postoperatively, all patients recovered uneventfully with no deaths or complications. The patients with III° AVB after device implantation recovered sinus rhythm postoperatively, and tricuspid apparatus injuries were surgically repaired with valvuloplasty. Transcatheter interventional VSD closure is safe and effective, but only under the conditions of strict patient selection, proper technique, and device application. Once severe complications are observed and diagnosed, devices should be retrieved immediately, and open heart surgery should be performed to avoid further injury.
One of the most important factors restricting heart transplantation is the limited myocardial ischemia time. This study investigated the effects of urethane on the hypothermic preservation of donor rat hearts.
The modification of proteins with O-linked N-acetylglucosamine (O-GlcNAc) is increasingly recognized as an important posttranslational modification that modulates cellular function. Recent studies suggested that augmentation of O-GlcNAc levels increase cell survival following stress. Salidroside, one of the active components of Rhodiola rosea, shows potent anti-hypoxia property. In the present study, we reported the cardioprotection of salidroside from ischemia and reperfusion. Cardiomyocytes were exposed to 4 h of ischemia and 16 h of reperfusion, and then cell viability, apoptosis, glucose uptake, ATP levels and cytosolic Ca(2+) concentration were determined, and O-GlcNAc levels were assessed by Western blotting. Salidroside (80 uM) was added 24 h before ischemia/reperfusion was induced. Treatment with salidroside markedly improved cell viability from 64.7+/-4.5% to 85.8+/-3.1%, decreased lactate dehydrogenase (LDH) release from 38.5+/-2.1% to 21.2+/-1.7%, reduced cell apoptosis from 27.2+/-3.2% to 12.2+/-1.9%, significantly improved cardiomyocytes glucose uptake by 1.7-fold and increased O-GlcNAc levels by 1.6-fold, as well as reducing cytosolic Ca(2+) concentration compared to untreated cells following ischemia/reperfusion. Furthermore, the improved cell survival and the increase in O-GlcNAc with salidroside were attenuated by alloxan, an inhibitor of O-GlcNAc transferase. These results suggested that salidroside significantly enhances glucose uptake and increases protein O-GlcNAc levels and this is associated with decreased cardiomyocytes injury following ischemia/reperfusion.
Previous studies have demonstrated that Notch signaling pathway plays a regulatory role in cellular oxidative stress injury (OSI). In this study, our aim was to explore the role of the Notch signaling pathway in hydrogen peroxide (H(2)O(2))-induced OSI and the protective effect of curcumin during (H(2)O(2))-induced injury in human umbilical vein endothelial cells (HUVECs). DAPT, a specific inhibitor of the Notch signaling pathway, and Notch1 siRNA were used to study Notch activity. Further, HUVECs were exposed to H(2)O(2) in the absence or presence of curcumin. DAPT and Notch1 siRNA significantly inhibited OSI and the expression of Notch1 and Hes1. Curcumin conferred a protective effect on the HUVECs against H(2)O(2), which was evidenced by improved cell viability, adhesive ability and migratory ability and a decreased apoptotic index, decreased production of reactive oxygen species (ROS) and a reduction in several biochemical parameters. Immunofluorescence and Western blotting analyses demonstrated that H(2)O(2) treatment upregulated the expression of Notch1, Hes1, Caspase3, Bax and cytochrome c downregulated the expression of Bcl2, and treatment with curcumin reversed these effects. We demonstrated for the first time that the inhibition of Notch signaling pathway imparts a protective effect against endothelial OSI. The protective effects of curcumin against OSI are at least in part dependent on Notch1 inhibition.
Myocardial ischemia/reperfusion injury (I/RI) is the principal cause of mortality and morbidity in diabetic patients undergoing cardiac surgery. However, there is no specific measure available to protect diabetic hearts in this clinical setting. Our clinical studies showed that adenosine pre-treatment or post-treatment and adding adenosine to cardioplegia solution had significant myocardial protective effects in patients undergoing cardiac surgery. However, the specific protective effects and mechanisms of adenosine in diabetic myocardial I/RI are not clear. Calpain is an important proteolytic enzyme in the myocardium. Studies show that the activation of calpain is an injury factor in not only the diabetic myocardium but also myocardial I/RI progression. We therefore hypothesize that adenosine play a protective role in diabetic myocardial I/RI through the inhibition of calpain.
In this study, we evaluated the effect of curcumin (Cur) post-treatment on isolated perfused rat hearts that had been subjected to a protocol of ischemia and reperfusion injury. We also examined whether the Janus kinase 2 and signal transducer and activator 3 of transcription (JAK2/STAT3) signaling pathway plays a role in the cardioprotective effects of Cur post-treatment. Isolated perfused rat hearts were subjected to 60 min of ischemia, followed by 60 min of reperfusion. The hearts were exposed to 1-?M Cur during the first 10 min of reperfusion in the absence or presence of the JAK kinase-specific inhibitor AG490 (AG, 1 ?M). The Cur treatment conferred a cardioprotective effect, and the treated hearts demonstrated an improved post-ischemic cardiac functional recovery, a decreased myocardial infarct size and decreased lactate dehydrogenase release in the coronary flow, a reduced number of apoptotic cardiomyocytes, up-regulation of the anti-apoptotic protein Bcl2 and down-regulation of the pro-apoptotic protein Caspase3. AG blocked the Cur-mediated cardioprotection by inhibiting the JAK2/STAT3 signaling pathway, as reflected by the abrogation of the Cur-induced up-regulation of Bcl2 and down-regulation of Caspase3. The results suggest that Cur post-treatment can attenuate IR injury through the activation of the JAK2/STAT3 signaling pathway, which transmits a survival signal to the myocardium.
Heat shock protein (HSP) 70 plays a critical role in protecting the heart from various stressor-induced cell injuries; the mechanism remains to be further understood. The present study aims to elucidate the effect of a probiotics-derived protein, LGG-derived protein p75 (LGP), in alleviating the ischemia/reperfusion (I/R)-induced heart injury. We treated rats with the I/R with or without preadministration with LGP. The levels of HSP70 and carboxy terminus of HSP70-interacting protein (CHIP) in the heart tissue were assessed by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The effect of CHIP on suppression of HSP70 and the effect of LGP on suppression of CHIP were investigated with an I/R rat model and a cell culture model. The results showed that I/R-induced infarction in the heart could be alleviated by pretreatment with LGP. HSP70 was detected in naïve rat heart tissue extracts. I/R treatment significantly suppressed the level of HSP70 and increased the levels of CHIP in the heart. A complex of CHIP/HSP70 was detected in heart tissue extracts. The addition of recombinant CHIP to culture inhibited HSP70 in heart cells. LGP was bound CHIP in heart cells and prevented the CHIP from binding HSP70. In summary, I/R can suppress HSP70 and increase CHIP in heart cells. CHIP can suppress HSP70 that can be prevented by pretreatment with LGP. The results imply that CHIP may be a potential target in the prevention of I/R-induced heart cell injury.
Related JoVE Video
Journal of Visualized Experiments
What is Visualize?
JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.
How does it work?
We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.
Video X seems to be unrelated to Abstract Y...
In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.