Regulation of metabolism by mitochondrial enzyme acetylation in cardiac ischemia-reperfusion injury

The role and mechanism of epigenetics in anticancer drug-induced cardiotoxicity

Cardiovascular disease is the main factor contributing to the global burden of diseases, and the cardiotoxicity caused by anticancer drugs is an essential component that cannot be ignored. With the development of anticancer drugs, the survival period of cancer patients is prolonged; however, the cardiotoxicity caused by anticancer drugs is becoming increasingly prominent. Currently, cardiovascular disease has emerged as the second leading cause of mortality among long-term cancer survivors. Anticancer drug-induced cardiotoxicity has become a frontier and hot topic. The discovery of epigenetics has given the possibility of environmental changes in gene expression, protein synthesis, and traits. It has been found that epigenetics plays a pivotal role in promoting cardiovascular diseases, such as heart failure, coronary heart disease, and hypertension. In recent years, increasing studies have underscored the crucial roles played by epigenetics in anticancer drug-induced cardiotoxicity. Here, we provide a comprehensive overview of the role and mechanisms of epigenetics in anticancer drug-induced cardiotoxicity.

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

β-hydroxybutyrate administered at reperfusion reduces infarct size and preserves cardiac function by improving mitochondrial function through autophagy in male mice

Ischemia/reperfusion (I/R) injury after revascularization contributes ∼50% of infarct size and causes heart failure, for which no established clinical treatment exists. β-hydroxybutyrate (β-OHB), which serves as both an energy source and a signaling molecule, has recently been reported to be cardioprotective when administered immediately before I/R and continuously after reperfusion. This study aims to determine whether administering β-OHB at the time of reperfusion with a single dose can alleviate I/R injury and, if so, to define the mechanisms involved. We found plasma β-OHB levels were elevated during ischemia in STEMI patients, albeit not to myocardial protection level, and decreased after revascularization. In mice, compared with normal saline, β-OHB administrated at reperfusion reduced infarct size (by 50%) and preserved cardiac function, as well as activated autophagy and preserved mtDNA levels in the border zone. Our treatment with one dose β-OHB reached a level achievable with fasting and strenuous physical activity. In neonatal rat ventricular myocytes (NRVMs) subjected to I/R, β-OHB at physiologic level reduced cell death, increased autophagy, preserved mitochondrial mass, function, and membrane potential, in addition to attenuating reactive oxygen species (ROS) levels. ATG7 knockdown/knockout abolished the protective effects of β-OHB observed both in vitro and in vivo. Mechanistically, β-OHB's cardioprotective effects were associated with inhibition of mTOR signaling. In conclusion, β-OHB, when administered at reperfusion, reduces infarct size and maintains mitochondrial homeostasis by increasing autophagic flux (potentially through mTOR inhibition). Since β-OHB has been safely tested in heart failure patients, it may be a viable therapeutic to reduce infarct size in STEMI patients.

Iron deficiency in myocardial ischaemia: molecular mechanisms and therapeutic perspectives

Systemic iron deficiency (SID), even in the absence of anaemia, worsens the prognosis and increases mortality in heart failure (HF). Recent clinical-epidemiological studies, however, have shown that a myocardial iron deficiency (MID) is frequently present in cases of severe HF, even in the absence of SID and without anaemia. In addition, experimental studies have shown a poor correlation between the state of systemic and myocardial iron. MID in animal models leads to severe mitochondrial dysfunction, alterations of mitophagy, and mitochondrial biogenesis, with profound alterations in cardiac mechanics and the occurrence of a fatal cardiomyopathy, all effects prevented by intravenous administration of iron. This shifts the focus to the myocardial state of iron, in the absence of anaemia, as an important factor in prognostic worsening and mortality in HF. There is now epidemiological evidence that SID worsens prognosis and mortality also in patients with acute and chronic coronary heart disease and experimental evidence that MID aggravates acute myocardial ischaemia as well as post-ischaemic remodelling. Intravenous administration of ferric carboxymaltose (FCM) or ferric dextrane improves post-ischaemic adverse remodelling. We here review such evidence, propose that MID worsens ischaemia/reperfusion injury, and discuss possible molecular mechanisms, such as chronic hyperactivation of HIF1-α, exacerbation of cytosolic and mitochondrial calcium overload, amplified increase of mitochondrial [NADH]/[NAD+] ratio, and depletion of energy status and NAD+ content with inhibition of sirtuin 1-3 activity. Such evidence now portrays iron metabolism as a core factor not only in HF but also in myocardial ischaemia.

Intermittent fasting promotes adipocyte mitochondrial fusion through Sirt3-mediated deacetylation of Mdh2

Fat deposition and lipid metabolism are closely related to the morphology, structure and function of mitochondria. The morphology of mitochondria between fusion and fission processes is mainly regulated by protein posttranslational modification. Intermittent fasting (IF) promotes high expression of Sirtuin 3 (Sirt3) and induces mitochondrial fusion in high-fat diet (HFD)-fed mice. However, the mechanism by which Sirt3 participates in mitochondrial protein acetylation during IF to regulate mitochondrial fusion and fission dynamics remains unclear. This article demonstrates that IF promotes mitochondrial fusion and improves mitochondrial function in HFD mouse inguinal white adipose tissue. Proteomic sequencing revealed that IF increased protein deacetylation levels in HFD mice and significantly increased Sirt3 mRNA and protein expression. After transfecting with Sirt3 overexpression or interference vectors into adipocytes, we found that Sirt3 promoted adipocyte mitochondrial fusion and improved mitochondrial function. Furthermore, Sirt3 regulates the JNK-FIS1 pathway by deacetylating malate dehydrogenase 2 (MDH2) to promote mitochondrial fusion. In summary, our study indicates that IF promotes mitochondrial fusion and improves mitochondrial function by upregulating the high expression of Sirt3 in HFD mice, promoting deacetylation of MDH2 and inhibiting the JNK-FIS1 pathway. This research provides theoretical support for studies related to energy limitation and animal lipid metabolism.

UBIAD1 effectively alleviated myocardial ischemia reperfusion injury by activating SIRT1/PGC1α

BACKGROUND AND OBJECTIVES

Myocardial ischemia-reperfusion injury (MIRI) threatens global health and lowers people's sense of happiness. Till now, the mechanism of MIRI has not been well-understood. Therefore, this study was designed to explore the role of UBIAD1 in MIRI as well as its detailed reaction mechanism.

METHODS

The mRNA and protein expressions of UBIAD1 before or after transfection were measured using RT-qPCR and western blot. Western blot was also adopted to measure the expressions of signaling pathway-, mitochondrial damage- and apoptosis-related proteins. Moreover, mitochondrial membrane potential and ATP level were verified by JC-1 immunofluorescence and ATP kits, respectively. With the application of CCK-8, LDH and CK-MB assays, the cell viability, LDH and CK-MB levels were evaluated, respectively. In addition, the cell apoptosis was detected using TUNEL. Finally, the expressions of ROS, SOD, MDA and CAT were measured using DCFH-DA, SOD, MDA and CAT assays, respectively.

RESULTS

In the present study, we found that UBIAD1 was downregulated in hypoxia-reoxygenation (H/R) -induced H9C2 cells and its upregulation could activate SIRT1/PGC1α signaling pathway. It was also found that UBIAD1 regulated mitochondrial membrane potential and ATP level via activating SIRT1/PGC1α signaling pathway. In addition, the injury of H/R-induced H9C2 cells could be relieved by UBIAD1 through the activation of SIRT1/PGC1α signaling pathway. Moreover, UBIAD1 exhibited inhibitory effects on apoptosis and oxidative stress of H/R-induced H9C2 cells through activating SIRT1/PGC1α signaling pathway.

CONCLUSION

To sum up, UBIAD1 could alleviate apoptosis, oxidative stress and H9C2 cell injury by activating SIRT1/PGC1α, which laid experimental foundation for the clinical treatment of MIRI.

Metabolomics analysis in rat hearts with ischemia/reperfusion injury after diazoxide postconditioning

Background: Diazoxide is a selective mitochondrial-sensitive potassium channel opening agent that has a definite effect on reducing myocardial ischemia/reperfusion injury (MIRI). However, the exact effects of diazoxide postconditioning on the myocardial metabolome remain unclear, which might contribute to the cardioprotective effects of diazoxide postconditioning. Methods: Rat hearts subjected to Langendorff perfusion were randomly assigned to the normal (Nor) group, ischemia/reperfusion (I/R) group, diazoxide (DZ) group and 5-hydroxydecanoic acid + diazoxide (5-HD + DZ) group. The heart rate (HR), left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), and maximum left ventricular pressure (+dp/dtmax) were recorded. The mitochondrial Flameng scores were analysed according to the ultrastructure of the ventricular myocardial tissue in the electron microscopy images. Rat hearts of each group were used to investigate the possible metabolic changes relevant to MIRI and diazoxide postconditioning. Results: The cardiac function indices in the Nor group were better than those in the other groups at the end point of reperfusion, and the HR, LVDP and +dp/dt_max of the Nor group at T2 were significantly higher than those of the other groups. Diazoxide postconditioning significantly improved cardiac function after ischaemic injury, and the HR, LVDP and +dp/dt_max of the DZ group at T2 were significantly higher than those of the I/R group, which could be abolished by 5-HD. The HR, LVDP and +dp/dt_max of the 5-HD + DZ group at T2 were significantly lower than those of the DZ group. The myocardial tissue in the Nor group was mostly intact, while it exhibited considerable damage in the I/R group. The ultrastructural integrity of the myocardium in the DZ group was higher than that in the I/R and 5-HD + DZ groups. The mitochondrial Flameng score in the Nor group was lower than that in the I/R, DZ and 5-HD + DZ groups. The mitochondrial Flameng score in the DZ group was lower than that in the I/R and 5-HD + DZ groups. Five metabolites, namely, L-glutamic acid, L-threonine, citric acid, succinate, and nicotinic acid, were suggested to be associated with the protective effects of diazoxide postconditioning on MIRI. Conclusion: Diazoxide postconditioning may improve MIRI via certain metabolic changes. This study provides resource data for future studies on metabolism relevant to diazoxide postconditioning and MIRI.

Deciphering mechanism of Zhishi-Xiebai-Guizhi Decoction against hypoxia/reoxygenation injury in cardiomyocytes by cell metabolomics: Regulation of oxidative stress and energy acquisition

Myocardial ischemia/reperfusion (MI/R) injury is a life-threatening syndrome with high morbidity and mortality. Zhishi-Xiebai-Guizhi Decoction (ZSXBGZD) is a classic traditional Chinese medicine formula, used to treat cardiovascular diseases for centuries. However, its underlying medicinal mechanism has not been clearly elucidated, which hinders its widespread application. Here, the curative effects and therapeutic mechanism of ZSXBGZD against MI/R were addressed based on an integration of pharmaceutical evaluation and cellular metabolomics. First, a hypoxia/reoxygenation (H/R) model in H9c2 cells was employed to resemble MI/R and multiple pharmacological indicators were performed to assess the efficacy of ZSXBGZD. The results showed that ZSXBGZD possessed exceptional ability in attenuating cardiomyocyte injury, concerning oxidative stress, mitochondrial dysfunction, energy acquisition and cell apoptosis. Furthermore, a cell metabolomics approach based on HILIC and UPLC-Q-TOF-MS coupled with multivariate analysis was conducted to explore the metabolic regulation of ZSXBGZD. 38 differential polar metabolites related to H/R were uncovered, and 34 of them were reversed to normal state after the treatment of ZSXBGZD, revealing the perturbations of energy metabolism and amino acid metabolism. Moreover, formula decomposition justified the combination of single herbs to form ZSXBZGD and confirmed the pivotal status of Allii Macrostemonis Bulbus and Trichosanthis Fructus.

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

Perspectives on pediatric congenital aortic valve stenosis: Extracellular matrix proteins, post translational modifications, and proteomic strategies

In heart valve biology, organization of the extracellular matrix structure is directly correlated to valve function. This is especially true in cases of pediatric congenital aortic valve stenosis (pCAVS), in which extracellular matrix (ECM) dysregulation is a hallmark of the disease, eventually leading to left ventricular hypertrophy and heart failure. Therapeutic strategies are limited, especially in pediatric cases in which mechanical and tissue engineered valve replacements may not be a suitable option. By identifying mechanisms of translational and post-translational dysregulation of ECM in CAVS, potential drug targets can be identified, and better bioengineered solutions can be developed. In this review, we summarize current knowledge regarding ECM proteins and their post translational modifications (PTMs) during aortic valve development and disease and contributing factors to ECM dysregulation in CAVS. Additionally, we aim to draw parallels between other fibrotic disease and contributions to ECM post-translational modifications. Finally, we explore the current treatment options in pediatrics and identify how the field of proteomics has advanced in recent years, highlighting novel characterization methods of ECM and PTMs that may be used to identify potential therapeutic strategies relevant to pCAVS.

Processed lateral root of Aconitum carmichaelii Debx.: A review of cardiotonic effects and cardiotoxicity on molecular mechanisms

Fuzi, the lateral root of A. carmichaelii Debx., is a typical traditional herbal medicine with both poisonousness and effectiveness, and often used in the treatment of heart failure and other heart diseases. In this review, we searched domestic and foreign literature to sort out the molecular mechanisms of cardiotonic and cardiotoxicity of Fuzi, also including its components. The major bioactive components of Fuzi for cardiotonic are total alkaloids, polysaccharide and the water-soluble alkaloids, with specific mechanisms manifested in the inhibition of myocardial fibrosis, apoptosis and autophagy, and improvement of mitochondrial energy metabolism, which involves RAAS system, PI3K/AKT, JAK/STAT, AMPK/mTOR signaling pathway, etc. Diester-diterpenoid alkaloids in Fuzi can produce cardiotoxic effects by over-activating Na⁺ and Ca²⁺ ion channels, over-activating NLRP3/ASC/caspase-3 inflammatory pathway and mitochondria mediated apoptosis pathway. And three clinically used preparations containing Fuzi are also used as representatives to summarize their cardiac-strengthening molecular mechanisms. To sum up, Fuzi has shown valuable cardiotonic effects due to extensive basic and clinical studies, but its cardiotonic mechanisms have not been systematically sorted out. Therefore, it is a need for deeper investigation in the mechanisms of water-soluble alkaloids with low content but obvious therapeutic effect, as well as polysaccharide.

Serum Metabolomics Reveals Distinct Profiles during Ischemia and Reperfusion in a Porcine Model of Myocardial Ischemia-Reperfusion

Acute myocardial infarction (MI) is one of the leading causes of death worldwide. Early identification of ischemia and establishing reperfusion remain cornerstones in the treatment of MI, as mortality and morbidity can be significantly reduced by establishing reperfusion to the affected areas. The aim of the current study was to investigate the metabolomic changes in the serum in a swine model of MI induced by ischemia and reperfusion (I/R) injury, and to identify circulating metabolomic biomarkers for myocardial injury at different phases. Female Yucatan minipigs were subjected to 60 min of ischemia followed by reperfusion, and serum samples were collected at baseline, 60 min of ischemia, 4 h of reperfusion, and 24 h of reperfusion. Circulating metabolites were analyzed using an untargeted metabolomic approach. A bioinformatic approach revealed that serum metabolites show distinct profiles during ischemia and during early and late reperfusion. Some notable changes during ischemia include accumulation of metabolites that indicate impaired mitochondrial function and N-terminally modified amino acids. Changes in branched-chain amino-acid metabolites were noted during early reperfusion, while bile acid pathway derivatives and intermediates predominated in the late reperfusion phases. This indicates a potential for such an approach toward identification of the distinct phases of ischemia and reperfusion in clinical situations.

Structural Analysis of Mitochondrial Dynamics-From Cardiomyocytes to Osteoblasts: A Critical Review

Mitochondria play a crucial role in cell physiology and pathophysiology. In this context, mitochondrial dynamics and, subsequently, mitochondrial ultrastructure have increasingly become hot topics in modern research, with a focus on mitochondrial fission and fusion. Thus, the dynamics of mitochondria in several diseases have been intensively investigated, especially with a view to developing new promising treatment options. However, the majority of recent studies are performed in highly energy-dependent tissues, such as cardiac, hepatic, and neuronal tissues. In contrast, publications on mitochondrial dynamics from the orthopedic or trauma fields are quite rare, even if there are common cellular mechanisms in cardiovascular and bone tissue, especially regarding bone infection. The present report summarizes the spectrum of mitochondrial alterations in the cardiovascular system and compares it to the state of knowledge in the musculoskeletal system. The present paper summarizes recent knowledge regarding mitochondrial dynamics and gives a short, but not exhaustive, overview of its regulation via fission and fusion. Furthermore, the article highlights hypoxia and its accompanying increased mitochondrial fission as a possible link between cardiac ischemia and inflammatory diseases of the bone, such as osteomyelitis. This opens new innovative perspectives not only for the understanding of cellular pathomechanisms in osteomyelitis but also for potential new treatment options.

Role of Higenamine in Heart Diseases: A Mini-Review

Higenamine, a natural product with multiple targets in heart diseases, is originally derived from Aconitum, which has been traditionally used in China for the treatment of heart disease, including heart failure, arrhythmia, bradycardia, cardiac ischemia/reperfusion injury, cardiac fibrosis, etc. This study is aimed to clarify the role of higenamine in heart diseases. Higenamine has effects on improving energy metabolism of cardiomyocytes, anti-cardiac fibroblast activation, anti-oxidative stress and anti-apoptosis. Accumulating evidence from various studies has shown that higenamine exerts a wide range of cardiovascular pharmacological effects in vivo and in vitro, including alleviating heart failure, reducing cardiac ischemia/reperfusion injury, attenuating pathological cardiac fibrosis and dysfunction. In addition, several clinical studies have reported that higenamine could continuously increase the heart rate levels of healthy volunteers as well as patients with heart disease, but there are variable effects on systolic blood pressure and diastolic blood pressure. Moreover, the heart protection and therapeutic effects of higenamine on heart disease are related to regulating LKB1/AMPKα/Sirt1, mediating the β2-AR/PI3K/AKT cascade, induction of heme oxygenase-1, suppressing TGF-β1/Smad signaling, and targeting ASK1/MAPK (ERK, P38)/NF-kB signaling pathway. However, the interventional effects of higenamine on heart disease and its underlying mechanisms based on experimental studies have not yet been systematically reviewed. This paper reviewed the potential pharmacological mechanisms of higenamine on the prevention, treatment, and diagnosis of heart disease and clarified its clinical applications. The literature shows that higenamine may have a potent effect on complex heart diseases, and proves the profound medicinal value of higenamine in heart disease.

Network Pharmacology-Based Investigation and Experimental Exploration of the Antiapoptotic Mechanism of Colchicine on Myocardial Ischemia Reperfusion Injury

Background: The beneficial effects of colchicine on cardiovascular disease have been widely reported in recent studies. Previous research demonstrated that colchicine has a certain protective effect on ischemic myocardium and has the potential to treat myocardial ischemia reperfusion injury (MIRI). However, the potential targets and pharmacological mechanism of colchicine to treat MIRI has not been reported.

Methods: In this study, we used network pharmacology and experimental verification to investigate the pharmacological mechanisms of colchicine for the treatment of MIRI. Potential targets of colchicine and MIRI related genes were screened from public databases. The mechanism of colchicine in the treatment of MIRI was determined by protein-protein interaction (PPI), gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Additionally, we evaluated the effect of colchicine on H9C2 cell activity using CCK-8 assays, observed the effect of colchicine on H9C2 cell apoptosis via flow cytometry, and further verified the expression of key targets after colchicine treated by Western blot.

Results: A total of 626 target genes for colchicine and 1549 MIRI disease targets were obtained. 138 overlapping genes were determined as potential targets of colchicine in treating MIRI. the PPI network analysis demonstrated that the targets linked to MIRI were ALB, TNF, ACTB, AKT1, IL6, TP53, IL1B, CASP3 and these targets showed nice affinity with colchicine in molecular docking experiments. The results of GO analysis and KEGG pathway enrichment demonstrated that the anti-MIRI effect of colchicine involves in apoptotic signaling pathway. Further tests suggested that colchicine can protect H9C2 cell from Hypoxia/Reoxygenation (H/R) injury through anti-apoptotic effects. Western blot results demonstrated that colchicine can inhibited MIRI induced apoptosis of H9C2 cell by enhancing the decreased levels of Caspase-3 in myocardial injure model induced by H/R and activating the PI3K/AKT/eNOS pathway.

Conclusions: we performed network pharmacology and experimental evaluation to reveal the pharmacological mechanism of colchicine against MIRI. The results from this study could provide a theoretical basis for the development and clinical application of colchicine.

Multiple pathways are responsible to the inhibitory effect of butorphanol on OGD/R-induced apoptosis in AC16 cardiomyocytes

Ischemic heart disease is the leading cause of cardiovascular mortality, which is related to cardiac myocyte apoptosis. Butorphanol is an opioid receptor agonist with potential cardioprotective function. The purpose of this work is to explore the function and mechanism of butorphanol in oxygen and glucose deprivation/reperfusion (OGD/R)-induced cardiomyocyte apoptosis. The overlapping targets of ischemic heart disease and butorphanol were analyzed according to GeneCards, ParmMapper, Cytoscape, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Human cardiomyocyte AC16 cells were incubated with butorphanol and then stimulated with OGD/R. Cell injury was investigated by Cell Counting Kit-8, lactate dehydrogenase (LDH) assay kit, TUNEL staining, caspase-3 activity assay kit, and Western blotting. The proteins in signaling pathways were measured using Western blotting. A total of 93 overlapping targets of ischemic heart disease and butorphanol were obtained. Pathway analysis exhibited that these targets might be involved in multiple signaling pathways. Butorphanol alone showed little cytotoxicity to cardiomyocytes, and it protected against OGD/R-induced viability inhibition, LDH release, cell apoptosis, and increase of caspase-3 activity and expression levels of cleaved caspase-3 and Bim. Butorphanol promoted the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/forkhead box O (FoxO) and hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathways and attenuated the activation of the mitogen-activated protein kinase (MAPK) signaling in OGD/R-treated cardiomyocytes. In conclusion, butorphanol prevents OGD/R-induced cardiomyocyte apoptosis through activating the PI3K/Akt/FoxO and HIF-1α/VEGF pathways and inactivating the MAPK pathway.

IL-22 ameliorated cardiomyocyte apoptosis in cardiac ischemia/reperfusion injury by blocking mitochondrial membrane potential decrease, inhibiting ROS and cytochrome C

Irreversible cardiomyocyte death is one of the main reasons of heart failure following cardiac injury. Therefore, controlling cardiomyocyte death is an effective method to delay the progression of cardiac disease after injury. IL-22 plays critical roles in tissue homeostasis and repair, and has become an important bridge between the immune system and specific tissues or organs. However, whether IL-22 can prevent of cardiomyocyte apoptosis from cardiac injury remains unclear. Therefore, the present work would address the above question. Our results showed that, in vitro, IL-22 prevented cardiomyocyte apoptosis induced by Angiotensin II via enhancing the activity of SOD, blocking the decrease of mitochondrial membrane potential, inhibiting ROS production and release of cytochrome C. The similar results were also found in vivo and patients. Our results shed a light on the therapy of cardiac injury.

A link between protein acetylation and mitochondrial dynamics under energy metabolism: A comprehensive overview

Cells adjust mitochondrial morphologies to coordinate between the cellular demand for energy and the availability of resources. Mitochondrial morphology is regulated by the balance between two counteracting mitochondrial processes of fusion and fission. Fission and fusion are dynamic and reversible processes that depend on the coordination of a number of proteins and are primarily regulated by posttranslational modifications. In the mitochondria, more than 20% of proteins are acetylated in proteomic surveys, partly involved in the dynamic regulation of mitochondrial fusion and fission. This article focuses on the molecular mechanism of the mitochondrial dynamics of fusion and fission, and summarizes the related mechanisms and targets of mitochondrial protein acetylation to regulate the mitochondrial dynamics of fusion and fission in energy metabolism.

The regulation of protein acetylation influences the redox homeostasis to protect the heart

The cellular damage caused by redox imbalance is involved in the pathogenesis of many cardiovascular diseases. Besides, redox imbalance is related to the alteration of protein acetylation processes, causing not only chromatin remodeling but also disturbances in so many processes where protein acetylation is involved, such as metabolism and signal transduction. The modulation of acetylases and deacetylases enzymes aids in maintaining the redox homeostasis, avoiding the deleterious cellular effects associated with the dysregulation of protein acetylation. Of note, regulation of protein acetylation has shown protective effects to ameliorate cardiovascular diseases. For instance, HDAC inhibition has been related to inducing cardiac protective effects and it is an interesting approach to the management of cardiovascular diseases. On the other hand, the upregulation of SIRT protein activity has also been implicated in the relief of cardiovascular diseases. This review focuses on the major protein acetylation modulators described, involving pharmacological and bioactive compounds targeting deacetylase and acetylase enzymes contributing to heart protection through redox homeostasis.

Sestrin2 as a gatekeeper of cellular homeostasis: Physiological effects for the regulation of hypoxia-related diseases

Sestrin2 (SESN2) is a conserved stress‐inducible protein (also known as hypoxia‐inducible gene 95 (HI95)) that is induced under hypoxic conditions. SESN2 represses the production of reactive oxygen species (ROS) and provides cytoprotection against various noxious stimuli, including hypoxia, oxidative stress, endoplasmic reticulum (ER) stress and DNA damage. In recent years, the determination of the regulation and signalling mechanisms of SESN2 has increased our understanding of its role in the hypoxic response. SESN2 has well‐documented roles in hypoxia‐related diseases, making it a potential target for diagnosis and treatment. This review discusses the regulatory mechanisms of SESN2 and highlights the significance of SESN2 as a biomarker and therapeutic target in hypoxia‐related diseases, such as cancer, respiratory‐related diseases, cardiovascular diseases and cerebrovascular diseases.

Restoration of NRF2 attenuates myocardial ischemia reperfusion injury through mediating microRNA-29a-3p/CCNT2 axis

Accumulated studies have been implemented for comprehending the mechanism of myocardial ischemia reperfusion injury (MI/RI). Nuclear factor erythroid-2 related factor 2 (NRF2)-mediated transcription activity in MI/RI has not been completely interpreted from the perspective of microRNA-29a-3p (miR-29a-3p) and cyclin T2 (CCNT2). Therein, this study intends to decode the mechanism of NRF2/miR-29a-3p/CCNT2 axis in MI/RI. Rat MI/RI models were established by left anterior descending artery ligation. Rats were injected with NRF2 or CCNT2 overexpression plasmids or miR-29a-3p agomir to explore their effects on MI/RI. Hypoxia/reoxygenation (H/R) cardiomyocytes were established and transfected with restored NRF2 or miR-29a-3p or CCNT2 for further exploration of their roles. NRF2, miR-29a-3p, and CCNT2 expression in myocardial tissues in rats with MI/RI and in cardiomyocytes in H/R injury were detected. ChIP assay verified the relationship between miR-29a-3p and NRF2, and the bioinformatics software and dual-luciferase reporter experiment verified the interaction between miR-29a-3p and CCNT2. NRF2 and miR-29a-3p were down-regulated while CCNT2 was up-regulated in myocardial tissues in rats with MI/RI and in H/R-treated cardiomyocytes. Restoration of NRF2 or miR-29a-3p improved hemodynamics and myocardial injury and suppressed serum inflammation and cardiomyocyte apoptosis via CCNT2 in rats with MI/RI. Upregulation of NRF2 or miR-29a-3p inhibited LDH and CK-MB activities, oxidative stress, and apoptosis and promoted viability of cardiomyocytes with H/R injury. NRF2 bound to the promoter of miR-29a-3p and CCNT2 was targeted by miR-29a-3p. This study elucidates that up-regulating NRF2 or miR-29a-3p attenuates MI/RI via inhibiting CCNT2, which may renew the existed knowledge of MI/RI-related mechanism and provide a novel guidance toward MI/RI treatment.

Protein acetylation in cardiac aging

Biological aging is attributed to progressive dysfunction in systems governing genetic and metabolic integrity. At the cellular level, aging is evident by accumulated DNA damage and mutation, reactive oxygen species, alternate lipid and protein modifications, alternate gene expression programs, and mitochondrial dysfunction. These effects sum to drive altered tissue morphology and organ dysfunction. Protein-acylation has emerged as a critical mediator of age-dependent changes in these processes. Despite decades of research focus from academia and industry, heart failure remains a leading cause of death in the United States while the 5 year mortality rate for heart failure remains over 40%. Over 90% of heart failure deaths occur in patients over the age of 65 and heart failure is the leading cause of hospitalization in Medicare beneficiaries. In 1931, Cole and Koch discovered age-dependent accumulation of phosphates in skeletal muscle. These and similar findings provided supporting evidence for, now well accepted, theories linking metabolism and aging. Nearly two decades later, age-associated alterations in biochemical molecules were described in the heart. From these small beginnings, the field has grown substantially in recent years. This growing research focus on cardiac aging has, in part, been driven by advances on multiple public health fronts that allow population level clinical presentation of aging related disorders. It is estimated that by 2030, 25% of the worldwide population will be over the age of 65. This review provides an overview of acetylation-dependent regulation of biological processes related to cardiac aging and introduces emerging non-acetyl, acyl-lysine modifications in cardiac function and aging.

Down-regulating miR-217-5p Protects Cardiomyocytes against Ischemia/Reperfusion Injury by Restoring Mitochondrial Function via Targeting SIRT1

Downregulating miR-217-5p could protect cardiomyocytes against ischemia/reperfusion (I/R) injury, but its role in restoring mitochondrial function of I/R-injured cardiomyocytes remained unclear. H9C2 cardiomyocyte-derived cell line with I/R injury was established in vitro on the basis of hypoxia/reperfusion (H/R) model. Cell viability and apoptosis were respectively detected by MTT assay and flow cytometry. Contents of lactate dehydrogenase (LDH) and adenosine triphosphate (ATP) were determined. Flow cytometry was performed to measure the production of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP). Target gene and potential binding sites between miR-217-5p and Sirtuin1 (SIRT1) were predicted by TargetScan and confirmed by dual-luciferase reporter assay. Relative SIRT1 and expressions of autophagy-related and apoptosis-related genes were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. After I/R treatment, the viability of H9C2 cardiomyocyte-derived cell line and ATP contents were reduced, but LDH and ROS contents were increased, at the same time, cell apoptosis and the expressions of miR-217-5p, p62 and cleaved caspase-3 were increased, whereas the expressions of SIRT1, LC3 (light chain 3), PINK1 (PTEN-induced kinase 1), Parkin, Bcl-2, and c-IAP (inhibitor of apoptosis protein) were reduced. However, downregulating miR-217-5p expression reversed the effects of I/R. SIRT1 was predicted and verified to be the target of miR-217-5p, and silencing SIRT1 reversed the effects of downregulating miR-217-5p on I/R-injured cells. Downregulating miR-217-5p could help restore mitochondrial function via targeting SIRT1, so as to protect cardiomyocytes against I/R-induced injury.

Molecular characterization and expression of sirtuin 2, sirtuin 3, and sirtuin 5 in the Wuchang bream (Megalobrama amblycephala) in response to acute temperature and ammonia nitrogen stress

This study sought to characterize sirtuin 2 (sirt2), sirtuin 3 (sirt3), and sirtuin 5 (sirt5) in Megalobrama amblycephala (M. amblycephala) by cloning the open reading frame (ORF) of sirt2, sirt3, and sirt5. The full-lengths of the resulting M. amblycephala sirt2, sirt3, and sirt5 cDNA sequences were 1845, 1534, and 1920 bp, respectively, with 92%, 98%, and 91% similarities to Danio rerio sequences. Based on our bioinformatic analyses and predictions, the sirt2 and sirt3 genes of M. amblycephala were classified within the Sir2 I family, whereas sirt5 belonged to the Sir2 III family. Furthermore, sirt2, sirt3, and sirt5 were widely distributed in different M. amblycephala tissues. Particularly, sirt2 and sirt5 were highly expressed in gills, intestines, and liver (P < 0.05), whereas sirt3 was highly expressed in gills, kidney, liver, and spleen (P < 0.05). A 2 × 2 factorial experiment was also conducted to analyze sirt2, sirt3, and sirt5 expression patterns in response to acute temperature (25 and 32 °C) and ammonia nitrogen (0 and 20 mg/L) stress. Notably, these two stressors were found to interactively affect sirt2, sirt3, and sirt5 expression patterns in M. amblycephala liver. At the higher water temperature (32 °C) and ammonia nitrogen concentration (20 mg/L) tested herein, sirt2, sirt3, and sirt5 had similar expression levels and exhibited a down-regulation trend at 6 and 48 h post-stress but became up-regulated thereafter to counteract the stressors at 96 h post-stress.

The Role of Arachidonic Acid Metabolism in Myocardial Ischemia-Reperfusion Injury

Patients with myocardial ischemic diseases or who are undergoing one of various heart treatments, such as open heart surgery, coronary artery bypass grafting, percutaneous coronary artery intervention or drug thrombolysis, face myocardial ischemia-reperfusion injury (MIRI). However, no effective treatment is currently available for MIRI. To improve the prognosis of people with cardiovascular disease, it is important to research the mechanism of MIRI. Arachidonic acid (AA) is one of the focuses of current research. The various metabolic pathways of AA are closely related to the development of cardiovascular disease, and the roles of various metabolites in ischemia-reperfusion injury have gradually been confirmed. AA is mainly metabolized in the cyclooxygenase (COX) pathway, lipoxygenase (LOX) pathway, and cytochrome P450 monooxygenase (CYP) pathway. This paper summarizes the progress of research on these three major AA metabolic pathways with respect to MIRI.