RESUMO
BACKGROUND: Exercise-induced physiological cardiac growth regulators may protect the heart from ischemia/reperfusion (I/R) injury. Homeobox-containing 1 (Hmbox1), a homeobox family member, has been identified as a putative transcriptional repressor and is downregulated in the exercised heart. However, its roles in exercise-induced physiological cardiac growth and its potential protective effects against cardiac I/R injury remain largely unexplored. METHODS: We studied the function of Hmbox1 in exercise-induced physiological cardiac growth in mice after 4 weeks of swimming exercise. Hmbox1 expression was then evaluated in human heart samples from deceased patients with myocardial infarction and in the animal cardiac I/R injury model. Its role in cardiac I/R injury was examined in mice with adeno-associated virus 9 (AAV9) vector-mediated Hmbox1 knockdown and in those with cardiac myocyte-specific Hmbox1 ablation. We performed RNA sequencing, promoter prediction, and binding assays and identified glucokinase (Gck) as a downstream effector of Hmbox1. The effects of Hmbox1 together with Gck were examined in cardiomyocytes to evaluate their cell size, proliferation, apoptosis, mitochondrial respiration, and glycolysis. The function of upstream regulator of Hmbox1, ETS1, was investigated through ETS1 overexpression in cardiac I/R mice in vivo. RESULTS: We demonstrated that Hmbox1 downregulation was required for exercise-induced physiological cardiac growth. Inhibition of Hmbox1 increased cardiomyocyte size in isolated neonatal rat cardiomyocytes and human embryonic stem cell-derived cardiomyocytes but did not affect cardiomyocyte proliferation. Under pathological conditions, Hmbox1 was upregulated in both human and animal postinfarct cardiac tissues. Furthermore, both cardiac myocyte-specific Hmbox1 knockout and AAV9-mediated Hmbox1 knockdown protected against cardiac I/R injury and heart failure. Therapeutic effects were observed when sh-Hmbox1 AAV9 was administered after I/R injury. Inhibition of Hmbox1 activated the Akt/mTOR/P70S6K pathway and transcriptionally upregulated Gck, leading to reduced apoptosis and improved mitochondrial respiration and glycolysis in cardiomyocytes. ETS1 functioned as an upstream negative regulator of Hmbox1 transcription, and its overexpression was protective against cardiac I/R injury. CONCLUSIONS: Our studies unravel a new role for the transcriptional repressor Hmbox1 in exercise-induced physiological cardiac growth. They also highlight the therapeutic potential of targeting Hmbox1 to improve myocardial survival and glucose metabolism after I/R injury.
Assuntos
Glucose , Proteínas de Homeodomínio , Traumatismo por Reperfusão Miocárdica , Miócitos Cardíacos , Animais , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Humanos , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Camundongos , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Glucose/metabolismo , Glucose/deficiência , Masculino , Sobrevivência Celular , Ratos , Camundongos Endogâmicos C57BL , Glicólise , Transdução de Sinais , Apoptose , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/genéticaRESUMO
Neutrophils are not only involved in immune defense against infection but also contribute to the exacerbation of tissue damage after ischemia and reperfusion. We have previously shown that genetic ablation of regulatory Gαi proteins in mice has both protective and deleterious effects on myocardial ischemia reperfusion injury (mIRI), depending on which isoform is deleted. To deepen and analyze these findings in more detail the contribution of Gαi2 proteins in resident cardiac vs circulating blood cells for mIRI was first studied in bone marrow chimeras. In fact, the absence of Gαi2 in all blood cells reduced the extent of mIRI (22,9% infarct size of area at risk (AAR) Gnai2-/- â wt vs 44.0% wt â wt; p < 0.001) whereas the absence of Gαi2 in non-hematopoietic cells increased the infarct damage (66.5% wt â Gnai2-/- vs 44.0% wt â wt; p < 0.001). Previously we have reported the impact of platelet Gαi2 for mIRI. Here, we show that infarct size was substantially reduced when Gαi2 signaling was either genetically ablated in neutrophils/macrophages using LysM-driven Cre recombinase (AAR: 17.9% Gnai2fl/fl LysM-Cre+/tg vs 42.0% Gnai2fl/fl; p < 0.01) or selectively blocked with specific antibodies directed against Gαi2 (AAR: 19.0% (anti-Gαi2) vs 49.0% (IgG); p < 0.001). In addition, the number of platelet-neutrophil complexes (PNCs) in the infarcted area were reduced in both, genetically modified (PNCs: 18 (Gnai2fl/fl; LysM-Cre+/tg) vs 31 (Gnai2fl/fl); p < 0.001) and in anti-Gαi2 antibody-treated (PNCs: 9 (anti-Gαi2) vs 33 (IgG); p < 0.001) mice. Of note, significant infarct-limiting effects were achieved with a single anti-Gαi2 antibody challenge immediately prior to vessel reperfusion without affecting bleeding time, heart rate or cellular distribution of neutrophils. Finally, anti-Gαi2 antibody treatment also inhibited transendothelial migration of human neutrophils (25,885 (IgG) vs 13,225 (anti-Gαi2) neutrophils; p < 0.001), collectively suggesting that a therapeutic concept of functional Gαi2 inhibition during thrombolysis and reperfusion in patients with myocardial infarction should be further considered.
Assuntos
Subunidade alfa Gi2 de Proteína de Ligação ao GTP , Camundongos Knockout , Traumatismo por Reperfusão Miocárdica , Neutrófilos , Animais , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Traumatismo por Reperfusão Miocárdica/imunologia , Traumatismo por Reperfusão Miocárdica/genética , Neutrófilos/metabolismo , Neutrófilos/imunologia , Subunidade alfa Gi2 de Proteína de Ligação ao GTP/metabolismo , Subunidade alfa Gi2 de Proteína de Ligação ao GTP/genética , Camundongos , Camundongos Endogâmicos C57BL , Masculino , Humanos , Modelos Animais de Doenças , Transdução de SinaisRESUMO
BACKGROUND: As an integral component of cell membrane repair machinery, MG53 (mitsugumin 53) is important for cardioprotection induced by ischemia preconditioning and postconditioning. However, it also impairs insulin signaling via its E3 ligase activity-mediated ubiquitination-dependent degradation of IR (insulin receptor) and IRS1 (insulin receptor substrate 1) and its myokine function-induced allosteric blockage of IR. Here, we sought to develop MG53 into a cardioprotection therapy by separating its detrimental metabolic effects from beneficial actions. METHODS: Using immunoprecipitation-mass spectrometry, site-specific mutation, in vitro kinase assay, and in vivo animal studies, we investigated the role of MG53 phosphorylation at serine 255 (S255). In particular, utilizing recombinant proteins and gene knock-in approaches, we evaluated the potential therapeutic effect of MG53-S255A mutant in treating cardiac ischemia/reperfusion injury in diabetic mice. RESULTS: We identified S255 phosphorylation as a prerequisite for MG53 E3 ligase activity. Furthermore, MG53S255 phosphorylation was mediated by GSK3ß (glycogen synthase kinase 3 beta) and markedly elevated in the animal models with metabolic disorders. Thus, IR-IRS1-GSK3ß-MG53 formed a vicious cycle in the pathogenesis of metabolic disorders where aberrant insulin signaling led to hyper-activation of GSK3ß, which in turn, phosphorylated MG53 and enhanced its E3 ligase activity, and further impaired insulin sensitivity. Importantly, S255A mutant eliminated the E3 ligase activity while retained cell protective function of MG53. Consequently, the S255A mutant, but not the wild type MG53, protected the heart against ischemia/reperfusion injury in db/db mice with advanced diabetes, although both elicited cardioprotection in normal mice. Moreover, in S255A knock-in mice, S255A mutant also mitigated ischemia/reperfusion-induced myocardial damage in the diabetic setting. CONCLUSIONS: S255 phosphorylation is a biased regulation of MG53 E3 ligase activity. The MG53-S255A mutant provides a promising approach for the treatment of acute myocardial injury, especially in patients with metabolic disorders.
Assuntos
Diabetes Mellitus Experimental , Traumatismo por Reperfusão , Camundongos , Animais , Fosforilação , Proteínas de Transporte/metabolismo , Serina/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Diabetes Mellitus Experimental/complicações , Proteínas de Membrana/metabolismo , Insulina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , IsquemiaRESUMO
The N7-methylguanosine (m7G) methyltransferase Mettl1 has been recently implicated in cardiac repair and fibrosis. In this study we investigated the role of Mettl1 in mouse cardiomyocytes injury and the underlying mechanisms. Cardiac ischemia/reperfusion (I/R) I/R model was established in mice by ligation of the left anterior descending coronary artery (LAD) for 45 min followed by reperfusion for 24 h. We showed the mRNA and protein levels of Mettl1 were significantly upregulated in mouse I/R hearts and H2O2-treated neonatal mouse cardiomyocytes (NMCMs). Mettl1 knockdown markedly ameliorated cardiac I/R injury, evidenced by decreased infarct size, apoptosis, and improved cardiac function. Overexpression of Mettl1 triggered cardiomyocytes apoptosis in vivo and in vitro. By performing RNA sequencing combined with m7G methylated RNA sequencing in Mettl1-overexpressing mouse hearts, we revealed that Mettl1 catalyzed m7G modification of the deubiquitinase cylindromatosis (CYLD) mRNA to increase the expression of CYLD, which enhanced the stability of P53 via abrogating its ubiquitination degradation. Vice versa, P53 served as a transcriptional factor to positively regulate Mettl1 expression during I/R injury. Knockdown of CYLD mitigated cardiomyocytes apoptosis induced by Mettl1 overexpression or oxidative stress. From the available drug-targets databases and literature, we identified 4 small molecule inhibitors of m7G modification. Sinefungin, one of the Mettl1 inhibitors exerted profound protection against cardiac I/R injury in vivo and in vitro. Collectively, this study has identified Mettl1 as a key regulator of cardiomyocyte apoptosis, and targeting the Mettl1-CYLD-P53 positive feedback circuit may represent a novel therapeutic avenue for alleviating cardiac I/R injury.
RESUMO
Myocardial ischemia-reperfusion (I/R) injury exacerbates cellular damage upon restoring blood flow to ischemic cardiac tissue, causing oxidative stress, inflammation, and apoptosis. This study investigates Nicotinamide Riboside (NR), a precursor of nicotinamide adenine dinucleotide (NAD+), for its cardioprotective effects. Administering NR to mice before I/R injury and evaluating heart function via echocardiography showed that NR significantly improved heart function, increased left ventricular ejection fraction (LVEF) and fractional shortening (FS), and reduced left ventricular end-diastolic (LVDd) and end-systolic diameters (LVSd). NR also restored E/A and E/e' ratios. It reduced cardiomyocyte apoptosis both in vivo and in vitro, inhibiting elevated caspase-3 activity and returning Bax protein levels to normal. In vitro, NR reduced the apoptotic rate in hydrogen peroxide (H2O2)-treated HL-1 cells from 30% to 10%. Mechanistically, NR modulated the SIRT3/mtROS/JNK pathway, reversing H2O2-induced SIRT3 downregulation, reducing mitochondrial reactive oxygen species (mtROS), and inhibiting JNK activation. Using SIRT3-knockout (SIRT3-KO) mice, we confirmed that NR's cardioprotective effects depend on SIRT3. Echocardiography showed that NR's benefits were abrogated in SIRT3-KO mice. In conclusion, NR provides significant cardioprotection against myocardial I/R injury by enhancing NAD+ levels and modulating the SIRT3/mtROS/JNK pathway, suggesting its potential as a novel therapeutic agent for ischemic heart diseases, meriting further clinical research.
Assuntos
Apoptose , Camundongos Knockout , Traumatismo por Reperfusão Miocárdica , Niacinamida , Compostos de Piridínio , Espécies Reativas de Oxigênio , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Camundongos , Compostos de Piridínio/farmacologia , Compostos de Piridínio/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Apoptose/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Humanos , Cardiotônicos/farmacologia , Cardiotônicos/uso terapêutico , Modelos Animais de Doenças , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacosRESUMO
Myocardial infarction and revascularization cause cardiac ischemia/reperfusion (I/R) injury featuring cardiomyocyte death and inflammation. The Ca2+/calmodulin dependent protein kinase II (CaMKII) family are serine/ threonine protein kinases that are involved in I/R injury. CaMKII exists in four different isoforms, α, ß, γ, and δ. In the heart, CaMKII-δ is the predominant isoformï¼with multiple splicing variants, such as δB, δC and δ9. During I/R, elevated intracellular Ca2+ concentrations and reactive oxygen species activate CaMKII. In this review, we summarized the regulation and function of CaMKII in multiple cell types including cardiomyocytes, endothelial cells, and macrophages during I/R. We conclude that CaMKII mediates inflammation in the microenvironment of the myocardium, resulting in cell dysfunction, elevated inflammation, and cell death. However, different CaMKII-δ variants exhibit distinct or even opposite functions. Therefore, reagents/approaches that selectively target specific CaMKII isoforms and variants are needed for evaluating and counteracting the exact role of CaMKII in I/R injury and developing effective treatments against I/R injury.
Assuntos
Infarto do Miocárdio , Traumatismo por Reperfusão Miocárdica , Humanos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Células Endoteliais/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Infarto do Miocárdio/metabolismo , Isoformas de Proteínas/metabolismoRESUMO
Prenatal hypoxia is associated with enhanced susceptibility to cardiac ischemia-reperfusion (I/R) injury in adult offspring, however, the mechanisms remain to be fully investigated. Endothelin-1 (ET-1) is a vasoconstrictor that acts via endothelin A (ETA) and endothelin B (ETB) receptors and is essential in maintaining cardiovascular (CV) function. Prenatal hypoxia alters the ET-1 system in adult offspring possibly contributing to I/R susceptibility. We previously showed that ex vivo application of ETA antagonist ABT-627 during I/R prevented the recovery of cardiac function in prenatal hypoxia-exposed males but not in normoxic males nor normoxic or prenatal hypoxia-exposed females. In this follow-up study, we examined whether placenta-targeted treatment with a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ) during hypoxic pregnancies could alleviate this hypoxic phenotype observed in adult male offspring. We used a rat model of prenatal hypoxia where pregnant Sprague-Dawley rats were exposed to hypoxia (11% O2) from gestational days (GD) 15-21 after injection with 100 µL saline or nMitoQ (125 µM) on GD15. Male offspring were aged to 4 mo and ex vivo cardiac recovery from I/R was assessed. Offspring born from hypoxic pregnancies and treated with nMitoQ had increased cardiac recovery from I/R in the presence of ABT-627 compared with their untreated counterparts where ABT-627 prevented recovery. Cardiac ETA levels were increased in males born from hypoxic pregnancies with nMitoQ treatment compared with saline controls (Western blotting). Our data indicate a profound impact of placenta-targeted treatment to prevent an ETA receptor cardiac phenotype observed in adult male offspring exposed to hypoxia in utero.NEW & NOTEWORTHY In this follow-up study, we showed a complete lack of recovery from I/R injury after the application of an ETA receptor antagonist (ABT-627) in adult male offspring exposed to hypoxia in utero while maternal treatment with nMitoQ during prenatal hypoxia exposure prevented this effect. Our data suggest that nMitoQ treatment during hypoxic pregnancies may prevent a hypoxic cardiac phenotype in adult male offspring.
Assuntos
Hipóxia , Receptores de Endotelina , Gravidez , Feminino , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Atrasentana , Seguimentos , Hipóxia/complicações , Placenta , Endotelina-1RESUMO
PURPOSE: There is an increasing body of evidence to show that impairment in mitochondrial dynamics including excessive fission and insufficient fusion has been observed in the pre-diabetic condition. In pre-diabetic rats with cardiac ischemia-reperfusion (I/R) injury, acute treatment with a mitochondria fission inhibitor (Mdivi-1) and a fusion promoter (M1) showed cardioprotection. However, the potential preventive effects of chronic Mdivi-1 and M1 treatment in a pre-diabetic model of cardiac I/R have never been elucidated. METHODS: Male Wistar rats (n = 40) were fed with a high-fat diet (HFD) for 12 weeks to induce prediabetes. Then, all pre-diabetic rats received the following treatments daily via intraperitoneal injection for 2 weeks: (1) HFDV (Vehicle, 0.1% DMSO); (2) HFMdivi1 (Mdivi-1 1.2 mg/kg); (3) HFM1 (M1 2 mg/kg); and (4) HFCom (Mdivi-1 + M1). At the end of treatment protocols, all rats underwent 30 min of coronary artery ligation followed by reperfusion for 120 min. RESULTS: Chronic Mdivi-1, M1, and the combined treatment showed markedly improved cardiac mitochondrial function and dynamic control, leading to a decrease in cardiac arrhythmias, myocardial cell death, and infarct size (49%, 42%, and 51% reduction for HFMdivi1, HFM1, and HFCom, respectively vs HFDV). All of these treatments improved cardiac function following cardiac I/R injury in pre-diabetic rats. CONCLUSION: Chronic inhibition of mitochondrial fission and promotion of fusion exerted cardioprevention in prediabetes with cardiac I/R injury through the relief of cardiac mitochondrial dysfunction and dynamic alterations, and reduction in myocardial infarction, thus improving cardiac function.
Assuntos
Diabetes Mellitus Experimental , Traumatismo por Reperfusão Miocárdica , Estado Pré-Diabético , Ratos , Masculino , Animais , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Traumatismo por Reperfusão Miocárdica/metabolismo , Ratos Wistar , Dinâmica Mitocondrial , Estado Pré-Diabético/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Miócitos Cardíacos , Mitocôndrias/metabolismo , ApoptoseRESUMO
Exercise and its regulated molecules have myocardial protective effects against cardiac ischemia/reperfusion (I/R) injury. The muscle-enriched miR-486 was previously identified to be upregulated in the exercised heart, which prompted us to investigate the functional roles of miR-486 in cardiac I/R injury and to further explore its potential in contributing to exercise-induced protection against I/R injury. Our data showed that miR-486 was significantly downregulated in the heart upon cardiac I/R injury. Both preventive and therapeutic interventions of adeno-associated virus 9 (AAV9)-mediated miR-486 overexpression could reduce cardiac I/R injury. Using AAV9 expressing miR-486 with a cTnT promoter, we further demonstrated that cardiac muscle cell-targeted miR-486 overexpression was also sufficient to protect against cardiac I/R injury. Consistently, miR-486 was downregulated in oxygen-glucose deprivation/reperfusion (OGDR)-stressed cardiomyocytes, while upregulating miR-486 inhibited cardiomyocyte apoptosis through PTEN and FoxO1 inhibition and AKT/mTOR activation. Finally, we observed that miR-486 was necessary for exercise-induced protection against cardiac I/R injury. In conclusion, miR-486 is protective against cardiac I/R injury and myocardial apoptosis through targeting of PTEN and FoxO1 and activation of the AKT/mTOR pathway, and mediates the beneficial effect of exercise for myocardial protection. Increasing miR-486 might be a promising therapeutic strategy for myocardial protection.
Assuntos
MicroRNAs , Traumatismo por Reperfusão Miocárdica , Apoptose/genética , Humanos , Isquemia/metabolismo , MicroRNAs/metabolismo , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismoRESUMO
Fetal hypoxia, a major consequence of complicated pregnancies, impairs offspring cardiac tolerance to ischemia-reperfusion (I/R) insult; however, the mechanisms remain unknown. Endothelin-1 (ET-1) signaling through the endothelin A receptors (ETA) is associated with cardiac dysfunction. We hypothesized that prenatal hypoxia exacerbates cardiac susceptibility to I/R via increased ET-1 and ETA levels, whereas ETA inhibition ameliorates this. Pregnant Sprague-Dawley rats were exposed to normoxia (21% O2) or hypoxia (11% O2) on gestational days 15-21. Offspring were aged to 4 mo, and hearts were aerobically perfused or subjected to ex vivo I/R, with or without preinfusion with an ETA antagonist (ABT-627). ET-1 levels were assessed with ELISA in aerobically perfused and post-I/R left ventricles (LV). ETA and ETB levels were assessed by Western blotting in nonperfused LV. As hypothesized, ABT-627 infusion tended to improve post-I/R recovery in hypoxic females (P = 0.0528); however, surprisingly, ABT-627 prevented post-I/R recovery only in the hypoxic males (P < 0.001). ET-1 levels were increased in post-I/R LV in both sexes regardless of the prenatal exposure (P < 0.01). ETA expression was similar among all groups, whereas ETB (isoform C) levels were decreased in prenatally hypoxic females (P < 0.05). In prenatally hypoxic males, ETA signaling may be essential for tolerance to I/R, whereas in prenatally hypoxic females, ETA may contribute to cardiac dysfunction. Our data illustrate that understanding the prenatal history has critical implications for treatment strategies in adult chronic diseases.NEW & NOTEWORTHY We demonstrated that prenatal hypoxia (a common condition of pregnancy) can have profound differential effects on treatment strategies in adult cardiovascular disease. Our data using a rat model of prenatal hypoxia demonstrated that, as adults, although inhibition of endothelin (ETA) receptors before an ex vivo cardiac ischemic insult improved recovery in females, it strikingly prevented recovery in males. Our data indicate a sex-specific effect of prenatal hypoxia on the cardiac ET-1 system in adult offspring.
Assuntos
Cardiopatias , Hipóxia , Animais , Atrasentana , Endotelina-1 , Endotelinas , Feminino , Isquemia/complicações , Masculino , Gravidez , Ratos , Ratos Sprague-Dawley , Receptor de Endotelina ARESUMO
OBJECTIVE: Microglial hyperactivation and apoptosis were observed following myocardial infarction and ischemia reperfusion (I/R) injury. This study aimed to test the hypothesis that the apoptosis inhibitor, Z-VAD, attenuates microglial and astrocytic hyperactivation and brain inflammation in rats with cardiac I/R injury. MATERIALS AND METHODS: Rats were subjected to either sham or cardiac I/R operation (30 min-ischemia followed by 120-min reperfusion), rats in the cardiac I/R group were given either normal saline solution or Z-VAD at 3.3 mg/kg via intravenous injection 15 min prior to cardiac ischemia. Left ventricular ejection fraction (% LVEF) was determined during the cardiac I/R protocol. The brain tissues were removed and used to determine brain apoptosis, brain inflammation, microglial and astrocyte morphology. RESULTS: Cardiac dysfunction was observed in rats with cardiac I/R injury as indicated by decreased %LVEF. In the brain, we found brain apoptosis, brain inflammation, microglia hyperactivation, and reactive astrogliosis occurred following cardiac I/R injury. Pretreatment with Z-VAD effectively increased %LVEF, reduced brain apoptosis, attenuated brain inflammation by decreasing IL-1ß mRNA levels, suppressed microglial and astrocytic hyperactivation and proliferation after cardiac I/R injury. CONCLUSION: Z-VAD exerts neuroprotective effects against cardiac I/R injury not only targeting apoptosis but also microglial and astrocyte activation.
Assuntos
Encefalite , Traumatismo por Reperfusão Miocárdica , Traumatismo por Reperfusão , Animais , Apoptose , Microglia , Ratos , Traumatismo por Reperfusão/tratamento farmacológico , Volume Sistólico , Função Ventricular EsquerdaRESUMO
Mitochondria are extraordinarily dynamic organelles that have a variety of morphologies, the status of which are controlled by the opposing processes of fission and fusion. Our recent study shows that inhibition of excessive mitochondrial fission by Drp1 inhibitor (Mdivi-1) leads to a reduction in infarct size and left ventricular (LV) dysfunction following cardiac ischemia-reperfusion (I/R) injury in high fat-fed induced pre-diabetic rats. In the present study, we investigated the cardioprotective effects of a mitochondrial fusion promoter (M1) and a combined treatment (M1 and Mdivi-1) in pre-diabetic rats. Wistar rats were given a high-fat diet for 12 weeks to induce prediabetes. The rats then subjected to 30 min-coronary occlusions followed by reperfusion for 120 min. These rats were intravenously administered M1 (2 mg/kg) or M1 (2 mg/kg) combined with Mdivi-1 (1.2 mg/kg) prior to ischemia, during ischemia or at the onset of reperfusion. We showed that administration of M1 alone or in combination with Mdivi-1 prior to ischemia, during ischemia or at the onset of reperfusion all significantly attenuated cardiac mitochondrial ROS production, membrane depolarization, swelling and dynamic imbalance, leading to reduced arrhythmias and infarct size, resulting in improved LV function in pre-diabetic rats. In conclusion, the promotion of mitochondrial fusion at any time-points during cardiac I/R injury attenuated cardiac mitochondrial dysfunction and dynamic imbalance, leading to decreased infarct size and improved LV function in pre-diabetic rats.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Estado Pré-Diabético/metabolismo , Animais , Diabetes Mellitus Experimental/induzido quimicamente , Dieta Hiperlipídica/efeitos adversos , Relação Dose-Resposta a Droga , Masculino , Dinâmica Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Traumatismo por Reperfusão Miocárdica/induzido quimicamente , Estado Pré-Diabético/induzido quimicamente , Quinazolinonas/farmacologia , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
Diabetic hearts are vulnerable to myocardial ischemia/reperfusion injury (IRI), but are insensitive to sevoflurane postconditioning (SPC), activating peroxiredoxins that confer cardioprotection. Previous studies have demonstrated that hydrogen sulfide (H2 S) can suppress oxidative stress of diabetic rats through increasing the expression of silent information regulator factor 2-related enzyme 1 (SIRT1), but whether cardioprotection by SPC can be restored afterward remains unclear. Diabetic rat was subjected to IRI (30 min of ischemia followed by 120 min reperfusion). Postconditioning treatment with sevoflurane was administered for 15 min upon the onset of reperfusion. The diabetic rats were treated with GYY4137 (H2 S donor) 5 days before the experiment. Myocardial infarct size, mitochondrial structure and function, ATP content, activities of complex I-IV, marker of oxidative stress, SIRT1, nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADPH Oxidase-2 (Nox-2) protein expression were detected after reperfusion, and cardiac function was evaluated by echocardiography at 24 h after reperfusion. After H2 S activated SIRT1 in the impaired myocardium of diabetic rats, SPC significantly upregulated the expression of Nrf2 and its downstream mediator HO-1, thus reduced the expression of Nox-2. In addition, H2 S remarkably increased cytoplasmic and nuclear SIRT1 which was further enhanced by SPC. Furthermore, H2 S combined with SPC reduced the production of reactive oxygen species, increased the content of ATP, and maintained mitochondrial enzyme activity. Finally, myocardial infarct size and myocardium damage were decreased, and cardiac function was improved. Taken together, our study proved that H2 S could restore SPC-induced cardioprotection in diabetic rats by enhancing and promoting SIRT1/Nrf2 signaling pathway mediated mitochondrial dysfunction and oxidative stress.
Assuntos
Cardiotônicos/farmacologia , Sulfeto de Hidrogênio/metabolismo , Infarto do Miocárdio/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Sevoflurano/farmacologia , Sirtuína 1/metabolismo , Animais , Diabetes Mellitus Experimental/patologia , Heme Oxigenase (Desciclizante)/metabolismo , Mitocôndrias/patologia , Morfolinas/farmacologia , Traumatismo por Reperfusão Miocárdica/patologia , NADPH Oxidase 2/metabolismo , Compostos Organotiofosforados/farmacologia , Estresse Oxidativo/fisiologia , Peroxirredoxinas/metabolismo , Ratos , Transdução de Sinais/fisiologiaRESUMO
Current evidence indicates that coronary microcirculation is a key target for protecting against cardiac ischemia-reperfusion (I/R) injury. Mitochondrial calcium uniporter (MCU) complex activation and mitochondrial calcium ([Ca2+]m) overload are underlying mechanisms involved in cardiovascular disease. Histidine triad nucleotide-binding 2 (HINT2) has been reported to modulate [Ca2+]m via the MCU complex, and our previous work demonstrated that HINT2 improved cardiomyocyte survival and preserved heart function in mice with cardiac ischemia. This study aimed to explore the benefits of HINT2 on cardiac microcirculation in I/R injury with a focus on mitochondria, the MCU complex, and [Ca2+]m overload in endothelial cells. The present work demonstrated that HINT2 overexpression significantly reduced the no-reflow area and improved microvascular perfusion in I/R-injured mouse hearts, potentially by promoting endothelial nitric oxide synthase (eNOS) expression and phosphorylation. Microvascular barrier function was compromised by reperfusion injury, but was repaired by HINT2 overexpression via inhibiting VE-Cadherin phosphorylation at Tyr731 and enhancing the VE-Cadherin/ß-Catenin interaction. In addition, HINT2 overexpression inhibited the inflammatory response by suppressing vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Mitochondrial fission occurred in cardiac microvascular endothelial cells (CMECs) subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury and resulted in mitochondrial dysfunction and mitochondrion-dependent apoptosis, the effects of which were largely relieved by HINT2 overexpression. Additional experiments confirmed that [Ca2+]m overload was an initiating factor for mitochondrial fission and that HINT2 suppressed [Ca2+]m overload via modulation of the MCU complex through directly interacting with MCU in CMECs. Regaining [Ca2+]m overload by spermine, an MCU agonist, abolished all the protective effects of HINT2 on OGD/R-injured CMECs and I/R-injured cardiac microcirculation. In conclusion, the present report demonstrated that HINT2 overexpression inhibited MCU complex-mitochondrial calcium overload-mitochondrial fission and apoptosis pathway, and thereby attenuated cardiac microvascular ischemia-reperfusion injury.
Assuntos
Canais de Cálcio/metabolismo , Cálcio , Hidrolases/metabolismo , Proteínas Mitocondriais/metabolismo , Traumatismo por Reperfusão , Animais , Cálcio/metabolismo , Células Endoteliais/metabolismo , Camundongos , Mitocôndrias , Miócitos Cardíacos/metabolismo , Traumatismo por Reperfusão/metabolismoRESUMO
Left ventricular (LV) dysfunction is commonly associated with a variety of health conditions including acute myocardial infarction and obesity/diabetes. In addition, administration of several pharmacological agents such as anticancer, antiviral, and immunosuppressive drugs has been shown to be related with LV dysfunction. The molecular mechanism responsible for LV dysfunction has been extensively studied, and it has been proposed that the overproduction of reactive oxygen species (ROS) plays a crucial role in the regulation of this function. Mitochondria require the balance between ROS production and antioxidants to maintain their appropriate function and to prevent excessive ROS production. Thus, the excessive production of ROS and the reduced scavenging process under any pathological conditions could disrupt mitochondrial function, leading to energy depletion with subsequent cell death. Therefore, maintenance of the balance between oxidative stress and antioxidants is essential. Resveratrol, a stilbene, has been investigated extensively, and potentially used to treat or prevent various cardiovascular diseases. Resveratrol directly upregulates antioxidative capacity by increasing antioxidant genes such as heme oxygenase-1, superoxide dismutase, catalase, and glutathione. In this review, accumulated data from in vitro, ex vivo, and in vivo studies regarding the effects of resveratrol on cardiac mitochondrial function in cardiac pathologies are comprehensively summarized and discussed. Since there is no conclusive available clinical study regarding the effects of resveratrol on cardiac mitochondrial function, this review also aims to encourage more clinical investigations to confirm findings from basic research. This comprehensive review will provide insight regarding the potential mechanistic roles of resveratrol in preventing and/or treating patients with cardiovascular diseases to improve LV function and their health status.
Assuntos
Cardiopatias , Estilbenos , Antioxidantes/metabolismo , Cardiopatias/tratamento farmacológico , Cardiopatias/prevenção & controle , Humanos , Mitocôndrias/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Resveratrol/farmacologia , Estilbenos/farmacologiaRESUMO
Acute myocardial infarction (AMI) is a fetal cardiovascular disease with high morbidity and mortality worldwide. In the present study, we elucidated the role of galectin-3 in preventing myocardial ischemic reperfusion injury. We found that galactin-3 was significantly up-regulated in the myocardium and cardiomyocyte subjected to ischemia/reperfusion (I/R) and hypoxia/reoxygenation (H/R) treatment, respectively. Galectin-3 knockdown significantly decreased the ischemic size of the left ventricular and the apoptosis of cardiomyocytes. Moreover, galectin-3 knockdown reversed the decrease of mitochondrial membrane potential and inhibited the inflammation response in myocardium and cultured cardiomyocyte induced by I/R and H/R, respectively. Further, this study revealed that galectin-3 interacted with bcl-2, instead of bax, in the cardiomyocyte, and regulated the phosphorylation of AKT, p70s6k, JNK, IκB and p65. Our findings demonstrated that galectin-3 could prevent myocardial I/R injury through interacting with bcl-2.
Assuntos
Apoptose/fisiologia , Galectina 3/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Galectina 3/genética , Técnicas de Silenciamento de Genes , Inflamação/metabolismo , Masculino , Potencial da Membrana Mitocondrial/fisiologia , Mitocôndrias/metabolismo , Ratos Sprague-Dawley , Regulação para CimaRESUMO
Donation after circulatory death (DCD) could improve donor heart availability; however, warm ischemia-reperfusion injury raises concerns about graft quality. Mechanical postconditioning (MPC) may limit injury, but mechanisms remain incompletely characterized. Therefore, we investigated the roles of glucose metabolism and key signaling molecules in MPC using an isolated rat heart model of DCD. Hearts underwent 20 minutes perfusion, 30 minutes global ischemia, and 60 minutes reperfusion with or without MPC (two cycles: 30 seconds reperfusion-30 seconds ischemia). Despite identical perfusion conditions, MPC either significantly decreased (low recovery = LoR; 32 ± 5%; p < 0.05), or increased (high recovery = HiR; 59 ± 7%; p < 0.05) the recovery of left ventricular work compared with no MPC (47 ± 9%). Glucose uptake and glycolysis were increased in HiR vs. LoR hearts (p < 0.05), but glucose oxidation was unchanged. Furthermore, in HiR vs. LoR hearts, phosphorylation of raptor, a downstream target of AMPK, increased (p < 0.05), cytochrome c release (p < 0.05) decreased, and TNFα content tended to decrease. Increased glucose uptake and glycolysis, lower mitochondrial damage, and a trend towards decreased pro-inflammatory cytokines occurred specifically in HiR vs. LoR MPC hearts, which may result from greater AMPK activation. Thus, we identify endogenous cellular mechanisms that occur specifically with cardioprotective MPC, which could be elicited in the development of effective reperfusion strategies for DCD cardiac grafts.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Morte , Glucose/metabolismo , Transplante de Coração/métodos , Traumatismo por Reperfusão/prevenção & controle , Doadores de Tecidos/provisão & distribuição , Condicionamento Pré-Transplante , Animais , Masculino , Modelos Animais , Ratos , Ratos WistarRESUMO
MicroRNAs (miRs) were involved in numerous cardiovascular diseases, especially ischemic heart diseases, but the miR changes during cardiac ischemia-reperfusion (I/R) injury following sevoflurane (SEV) preconditioning are still unknown. This study aims to investigate the effect of miR-874 on cardiac I/R injury in mouse models pretreated with SEV. Following establishment of mouse models with myocardial I/R injury, mice were pretreated with SEV. The functional mechanism of miR-874 in I/R injury was explored when miR-874 and the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway were inhibited. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP biotin nick-end labeling (TUNEL) staining was used to detect cardiomyocyte apoptosis and dual luciferase reporter gene assay to identify the targeting relationship between miR-874 and STAT3. Expression of the JAK2/STAT3 signaling pathway and apoptosis-related genes was determined. Initially, upregulated miR-874 was observed in I/R mice. Then, miR-874 inhibition improved cardiac function of I/R mice, inhibited cardiomyocyte apoptosis (also shown as decreased Bcl-2 associated X protein B [Bax] and increased B-cell lymphoma-2 [Bcl-2]), and activated the JAK2/STAT3 signaling pathway. STAT3, a target gene of miR-874, was upregulated following miR-874 inhibition. Finally, we also observed that the effect of miR-874 was lost when the JAK2/STAT3 signaling pathway was blocked. The findings indicate miR-874 as a contributory role in cardiac I/R injury, with miR-874 inhibition alleviating cardiac I/R injury in mice following SEV pretreatment by targeting STAT3 through the JAK2/STAT3 signaling pathway.
Assuntos
Apoptose/fisiologia , MicroRNAs/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Modelos Animais de Doenças , Masculino , Camundongos , Transdução de Sinais/fisiologiaRESUMO
Berberine (BBR) is an isoquinnoline derivative alkaloid extracted from Rhizoma Coptidis that has the potential to protect myocardial tissues from ischemia/reperfusion (I/R) injuries. We attempted to evaluate the effect of BBR on the proliferation and apoptosis of a hypoxia/reoxygenation (H/R) cell model and to reveal the mechanism driving the improving function of BBR myocardial tissues. The H/R cell model was established using H9c2 rat cardiac myoblasts. The cell viability, apoptotic rates, and cell cycle distribution were measured with CCK-8 assay and flow cytometry. The expression of Smad7 and caspase-3 were determined both at mRNA and protein levels. In addition, expression of Smad7 was knocked down with specific siRNA and the effect of the interference was assessed. The proliferation ability of H/R cells was enhanced after the administration of BBR, and the apoptosis and cell cycle arrest due to H/R injury were also alleviated by BBR treatment. Moreover, the treatment of BBR on H/R injury functioned through the Smad7-activation-induced attenuating of apoptosis by activating Smad7 pathway which resulted suppression of caspase 3 expression and activity. The knockdown of Smad7 confirmed our conclusion about the key role of Smad7 in the function of BBR administration. However, our results as well as some previous studies also demonstrated that the effect of BBR was tissue and protocol specific, and the underlying mechanism related to the BBR treatment was so complicated that practical application should be carefully investigated based on certain diseases and patients.
Assuntos
Apoptose , Berberina/uso terapêutico , Cardiotônicos/uso terapêutico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/metabolismo , Proteína Smad7/metabolismo , Animais , Apoptose/efeitos dos fármacos , Berberina/administração & dosagem , Berberina/farmacologia , Cardiotônicos/farmacologia , Caspase 3/metabolismo , Inibidores de Caspase/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Inativação Gênica/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/patologia , RatosRESUMO
The prevalence of chronic pain increases with age. The pain occurrence in the elderly ranges from 25% to 80% in different countries. Ischemic heart disease is also prevailing in the aged people. Restored blood flow quickly rescues myocardium but also causes ischemia-reperfusion (IR) injury. Brief episodes of ischemia at a distant organ could reduce the myocardial reperfusion injury. This is called remote ischemic preconditioning (RIPC) cardioprotection. Several circulating factors and neurogenic signals contribute to the cardioprotection by RIPC. Preinfarction angina, a form of chest pain, is associated with significant cardioprotection in myocardial infarction patients. Activation of peripheral nociception also induces cardioprotection against IR injury via neurogenic pathway. It is possible that angina also induces nociceptive signal pathway to provide cardioprotection. It is unclear whether pre-existing chronic pain will also have a cardioprotection effect. We recently reported chronic neuropathic pain attenuates cardiac IR injury in mice. ERK activation in anterior nucleus of paraventricular thalamus (PVA) is required for this remote cardioprotection. Direct activation of PVA neurons also provides cardioprotection against cardiac IR injury. Chronic neuropathic pain-induced cardioprotection requires activation of parasympathetic nerves. This review summarizes the potential interaction of chronic pain and cardiac IR injury.