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BACKGROUND: We sought to explore the relationship between dexmedetomidine as an anesthetic adjuvant in cardiac surgery and postoperative complications and length of stay (LOS) in the cardiac intensive care unit (CICU). METHODS: We conducted a retrospective study of patients aged 18 years and older who underwent heart valve surgery between October 2020 and June 2022. The primary endpoint of the study was major postoperative complications (cardiac arrest, atrial fibrillation, myocardial injury/infarction, heart failure) and the secondary endpoint was prolonged CICU LOS (defined as LOS > 90th percentile). Multivariate logistic regression analysis was performed for variables that were significant in the univariate analysis. RESULTS: A total of 856 patients entered our study. The 283 patients who experienced the primary and secondary endpoints were included in the adverse outcomes group, and the remaining 573 were included in the prognostic control group. Multivariate logistic regression analysis revealed that age > 60 years (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.23-2.31; p < 0.01), cardiopulmonary bypass (CPB) > 180 min (OR, 1.62; 95% CI, 1.03-2.55; p = 0.04) and postoperative mechanical ventilation time > 10 h (OR, 1.84; 95% CI, 1.35-2.52; p < 0.01) were independent risk factors for major postoperative complications; Age > 60 years (OR, 3.20; 95% CI, 1.65-6.20; p < 0.01), preoperative NYHA class 4 (OR, 4.03; 95% CI, 1.74-9.33; p < 0.01), diabetes mellitus (OR, 2.57; 95% CI, 1.22-5.41; p = 0.01), Intraoperative red blood cell (RBC) transfusion > 650 ml (OR, 2.04; 95% CI, 1.13-3.66; p = 0.02), Intraoperative bleeding > 1200 ml (OR, 2.69; 95% CI, 1.42-5.12; p < 0.01) were independent risk factors for prolonged CICU length of stay. Intraoperative use of dexmedetomidine as an anesthetic adjunct was a protective factor for major complications (odds ratio, 0.51; 95% confidence interval, 0.35-0.74; p < 0.01) and prolonged CICU stay. (odds ratio, 0.37; 95% confidence interval, 0.19-0.73; p < 0.01). CONCLUSIONS: In patients undergoing heart valve surgery, age, duration of cardiopulmonary bypass, and duration of mechanical ventilation are associated with major postoperative complication. Age, preoperative NYHA classification 4, diabetes mellitus, intraoperative bleeding, and RBC transfusion are associated with increased CICU length of stay. Intraoperative use of dexmedetomidine may improve such clinical outcomes.
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Procedimientos Quirúrgicos Cardíacos , Dexmedetomidina , Diabetes Mellitus , Humanos , Dexmedetomidina/uso terapéutico , Tiempo de Internación , Estudios Retrospectivos , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Unidades de Cuidados Intensivos , Factores de Riesgo , Válvulas Cardíacas/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiologíaRESUMEN
Studies in the past decades have uncovered an emerging role of the nucleolus in stress response and human disease progression. The disruption of ribosome biogenesis in the nucleolus causes aberrant nucleolar architecture and function, termed nucleolar stress, to initiate stress-responsive pathways via nucleolar release sequestration of various proteins. While data obtained from both clinical and basic investigations have faithfully demonstrated an involvement of nucleolar stress in the pathogenesis of cardiomyopathy, much remains unclear regarding its precise role in the progression of cardiac diseases. On the one hand, the initiation of nucleolar stress following acute myocardial damage leads to the upregulation of various cardioprotective nucleolar proteins, including nucleostemin (NS), nucleophosmin (NPM) and nucleolin (NCL). As a result, nucleolar stress plays an important role in facilitating the survival and repair of cardiomyocytes. On the other hand, abnormalities in nucleolar architecture and function are correlated with the deterioration of cardiac diseases. Notably, the cardiomyocytes of advanced ischemic and dilated cardiomyopathy display impaired silver-stained nucleolar organiser regions (AgNORs) and enlarged nucleoli, resembling the characteristics of tissue aging. Collectively, nucleolar abnormalities are critically involved in the development of cardiac diseases.
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Besides the canonical function in ribosome biogenesis, there have been significant recent advances towards the fascinating roles of the nucleolus in stress response, cell destiny decision and disease progression. Nucleolar stress, an emerging concept describing aberrant nucleolar structure and function as a result of impaired rRNA synthesis and ribosome biogenesis under stress conditions, has been linked to a variety of signaling transductions, including but not limited to Mdm2-p53, NF-κB and HIF-1α pathways. Studies have uncovered that nucleolus is a stress sensor and signaling hub when cells encounter various stress conditions, such as nutrient deprivation, DNA damage and oxidative and thermal stress. Consequently, nucleolar stress plays a pivotal role in the determination of cell fate, such as apoptosis, senescence, autophagy and differentiation, in response to stress-induced damage. Nucleolar homeostasis has been involved in the pathogenesis of various chronic diseases, particularly tumorigenesis, neurodegenerative diseases and metabolic disorders. Mechanistic insights have revealed the indispensable role of nucleolus-initiated signaling in the progression of these diseases. Accordingly, the intervention of nucleolar stress may pave the path for developing novel therapies against these diseases. In this review, we systemically summarize recent findings linking the nucleolus to stress responses, signaling transduction and cell-fate decision, set the spotlight on the mechanisms by which nucleolar stress drives disease progression, and highlight the merit of the intervening nucleolus in disease treatment.
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FN-kappa B , Proteína p53 Supresora de Tumor , Nucléolo Celular/metabolismo , Progresión de la Enfermedad , Humanos , FN-kappa B/metabolismo , Transcripción Genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Nucleostemin (NS)/GNL3 protein has been recently documented to be a nucleolar protein that was abundantly expressed in stem cells and cancer cells. Herein, we showed that NS was upregulated in HCC tissues and the expression of NS was inversely correlated with that of p53. Overexpression of NS predicted significantly worsened prognosis in HCC patients, suggesting that NS might serve as a prognostic marker of HCC. In addition, we found that depletion of NS sensitized HCC cells to sorafenib-induced apoptosis. Moreover, we found that the mechanism underlying NS-mediated sorafenib resistance involved dysregulated expression of p53, and downstream Bax and Bcl-2 proteins. NS interacted with p53 in HCC cells. Depletion of NS increased the expression of p53 and Bax, whereas impaired the level of cellular Bcl-2. Interference of NS enhanced the cytotoxic effects of sorafenib in HCC cells. Furthermore, ectopic expression of NS impaired the apoptosis of HCC cells following sorafenib exposure. Therefore, NS may contribute to sorafenib resistance in HCC cells through the modulation of p53 pathway and Bcl-2 proteins. These findings indicated that the combination of silencing NS expression and sorafenib treatment is a promising therapeutic strategy in treatment of HCC.
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Antineoplásicos/uso terapéutico , Carcinoma Hepatocelular/metabolismo , Resistencia a Antineoplásicos/fisiología , Proteínas de Unión al GTP/metabolismo , Neoplasias Hepáticas/metabolismo , Niacinamida/análogos & derivados , Proteínas Nucleares/metabolismo , Compuestos de Fenilurea/uso terapéutico , Adulto , Anciano , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Femenino , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Niacinamida/farmacología , Niacinamida/uso terapéutico , Compuestos de Fenilurea/farmacología , Pronóstico , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Sorafenib , Tasa de Supervivencia , Regulación hacia Arriba , Adulto Joven , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Myocardial ischemia and reperfusion (MIR) results in cardiomyocyte apoptosis with severe outcomes, which blocks cardiac tissue recovering from myocardial ischemia diseases. Heat shock protein 70 (HSP70) is one of protective molecule chaperones which could regulate the nucleus translocation of other proteins. In addition, eukaryotic elongation factor 2 (eEF2), which modulates protein translation process, is vital to the recovery of heart during MIR. However, the relationship between HSP70 and eEF2 and its effects on MIR are unclear. The expression and relationship between HSP70 and eEF2 is confirmed by western blot, immunoprecipitation in vitro using cardiomyocyte cell line H9c2 and in vivo rat MIR model. The further investigation was conducted in H9c2 cells with detection for cell-cycle and apoptosis. It is revealed that eEF2 interacted and be regulated by HSP70, which kept eEF2 as dephosphorylated status and preserved the function of eEF2 during MIR. In addition, HSP70 suppressed the nucleus translocation of phosphorylated eEF2, which inhibited cardiomyocyte apoptosis during myocardial reperfusion stage. Furthermore, HSP70 also interacted with C-terminal fragment of eEF2, which could reverse the nucleus translocation and cardiomyocyte apoptosis caused by N-terminal fragment of eEF2. HSP70 draw on advantage and avoid defect of MIR through regulating phosphorylation and nucleus translocation of eEF2.
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Apoptosis/genética , Quinasa del Factor 2 de Elongación/genética , Proteínas HSP70 de Choque Térmico/genética , Daño por Reperfusión Miocárdica/genética , Animales , Transporte Biológico/genética , Línea Celular , Núcleo Celular/genética , Regulación de la Expresión Génica/genética , Humanos , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/patología , Fosforilación , Ratas , SumoilaciónRESUMEN
BACKGROUND: Cardiomyocyte apoptosis after myocardial ischemia reperfusion (MIR) blocks the recovery of cardiac function during revascularization treatment. Protein synthesis mediated by eukaryotic elongation factor 2 (eEF2) is vital for the recovery of MIR. eEF2 promotes peptide elongation without phosphorylation of itself. However, the exact function of eEF2 during MIR is unknown. METHODS: We used suture tie-down of left coronary artery (LCA) to induce MIR in vivo, which was confirmed by electrocardiography and Evan's blue/triphenyltetrazolium chloride double staining. Hypoxia/reoxygenation (H/R) treatment was utilized to stimulate H9c2 cells, which was detected by CCK8 assay to evaluate cell viability. eEF2, phosphorylated eEF2, SUMO, Bax, and Bcl-2 protein expressions and location of eEF2 and phosphorylated eEF2 were determined by western blot, immunocytochemistry and immunofluorescent staining. H9c2 cell apoptosis was assessed by flow cytometry. The effects of eEF2 full-length plasmid and its fragments on H9c2 cells were also detected. RESULTS: In vivo, phosphorylated eEF2 to eEF2 ratio decreased gently in rat MIR model. Immunocytochemistry showed that phosphorylated eEF2 translocated to the nucleus of cardiomyocytes during myocardial reperfusion. Furthermore, double immunofluorescent staining in H9c2 cells after H/R treatment also showed phosphorylated eEF2 translocated to the nucleus. Meanwhile, SUMOylation of eEF2 was detected. The overexpression of eEF2 upregulated Bcl-2 expression after H/R treatment, suggesting that eEF2 might reduce cardiomyocyte apoptosis during MIR. In addition, the N-terminal fragment of eEF2 transfection could promote apoptosis. CONCLUSIONS: eEF2 plays a bidirectional role in regulating cardiomyocyte apoptosis during MIR, in which eEF2 can be SUMOylated and translocate into nucleus of cardiomyocytes to promote cardiomyocyte apoptosis when eEF2 is phosphorylated.
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Apoptosis , Reperfusión Miocárdica , Miocitos Cardíacos/patología , Sumoilación , Animales , Modelos Animales de Enfermedad , Masculino , Factor 2 de Elongación Peptídica/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ratas Sprague-Dawley , Proteína X Asociada a bcl-2/metabolismoRESUMEN
p27kip, as a cyclin dependent kinase inhibitor (CDKI), plays a pivotal role in the regulation of cell cycle progression and hepatocarcinogenesis. Herein, we revealed that p27 exhibited apparent nucleolar distribution and interacted with nucleolar protein nucleostemin (NS) in Hepatocellular carcinoma (HCC) cells. Furthermore, subcellular fractionation experiments demonstrated that nucleolar p27 had significantly higher level of polyubiquitylation, compared with nucleoplasmic fraction. Depletion of NS inhibited nucleolar polyubiquitylation of p27, indicating an involvement of NS in triggering p27 ubiquitylation and inactivation during HCC development. Moreover, we found that knockdown of NS promoted p27 to bind to CDK2-Cyclin E complex and inhibited the activity of CDK2, resulting in consequent cell cycle arrest in HCC cells. Furthermore, silencing NS expression reduced in vitro colony formation and in vivo tumor growth of HCC cells. Finally, we found that NS was upregulated in HCC tissues, compared with adjacent non-tumorous tissues. Kaplan-Meier analysis indicated patients with high expression of NS and low expression of p27 had significantly worsened prognosis. Our results suggested NS mediated p27-dependent cell cycle control via inducing nucleolar sequestration and polyubiquitylation of p27 in HCC. These findings help gain an insightful view into the mechanism underlying aberrant cell cycle progression during hepatocarcinogenesis, and thus benefit the development of molecular-targeted therapies in HCC.
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Carcinoma Hepatocelular/genética , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/metabolismo , Proteínas de Unión al GTP/metabolismo , Neoplasias Hepáticas/genética , Proteínas Nucleares/metabolismo , Animales , Carcinoma Hepatocelular/patología , Femenino , Humanos , Neoplasias Hepáticas/patología , Ratones , Ratones Desnudos , TransfecciónRESUMEN
Phosphoglycerate mutase 5 (PGAM5) is a mitochondrial membrane protein that plays crucial roles in necroptosis and apoptosis. Though PGAM5 is known to be required for inducing intrinsic apoptosis through interacting with BCL2 associated X protein (Bax) and dynamin-related protein 1 (Drp1), the expression and role of PGAM5 in cardiomyocyte apoptosis driven by myocardial ischemia/reperfusion injury(MIRI) has not been studied. The present study shows that PGAM5 expression decreased after MIRI in vivo, positively correlated with Bcl-xL expression, negatively correlated with Kelch-ECH associating protein 1 (Keap1) expression. Furthermore, PGAM5 expression also decreased in cardiomyocytes after hypoxia/reoxygenation (H/R) treatment in vitro. PGAM5 silence promoted cardiomyocyte apoptosis and inhibited Bcl-xL expression, but with no effect on Keap1 expression. Accordingly, Keap1 overexpression further inhibited Bcl-xL and PGAM5 expression. Additionally, PGAM5-Bcl-xL-Keap1 interaction was identified, suggesting that PGAM5 might participate in the degradation of Bcl-xL mediated by Keap1. In summary, PGAM5 controls cardiomyocyte apoptosis induced by MIRI through regulating Keap1-mediated Bcl-xL degradation, which may supply a novel molecular target for acute myocardial infarction (AMI) therapy. Graphical abstract á .
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Proteína 1 Asociada A ECH Tipo Kelch/biosíntesis , Infarto del Miocardio/genética , Daño por Reperfusión Miocárdica/genética , Fosfoproteínas Fosfatasas/genética , Proteína bcl-X/biosíntesis , Animales , Apoptosis/genética , Modelos Animales de Enfermedad , Dinaminas/biosíntesis , Humanos , Proteína 1 Asociada A ECH Tipo Kelch/genética , Mitocondrias/genética , Mitocondrias/metabolismo , Infarto del Miocardio/patología , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Necrosis/genética , Necrosis/patología , Fosfoproteínas Fosfatasas/biosíntesis , Ratas , Proteína bcl-X/genéticaRESUMEN
Poly(C)binding protein 2 (PCBP2) is a member of the PCBP family, and plays an important role in posttranscriptional and translational regulation of various signaling molecules through direct binding to singlestranded poly(C) motifs. PCBP2 has been reported to play a critical role in the development of multiple human tumors. However, whether PCBP2 participates in hepatocellular carcinoma (HCC) development remains largely elusive. Herein, we showed that PCBP2 was upregulated in human HCC tissues and cell lines. Overexpression of PCBP2 predicted significantly worsened prognosis in HCC patients, suggesting that PCBP2 may serve as a prognostic marker of HCC. In addition, we found that depletion of PCBP2 inhibited HCC cell proliferation, accompanying the increase in the cyclindependent kinase inhibitor p27 level. Moreover, we found that high expression of PCBP2 may contribute to sorafenib resistance in HCC cells, involving dysregulated expression of Bax and Bcl2 proteins. In conclusion, our results suggest that PCBP2 may serve as a prognostic marker and potential therapeutic target of HCC.
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Carcinoma Hepatocelular/metabolismo , Proliferación Celular , Neoplasias Hepáticas/metabolismo , Proteínas de Unión al ARN/metabolismo , Adulto , Anciano , Antineoplásicos/farmacología , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Resistencia a Antineoplásicos , Femenino , Expresión Génica , Humanos , Concentración 50 Inhibidora , Estimación de Kaplan-Meier , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Niacinamida/análogos & derivados , Niacinamida/farmacología , Compuestos de Fenilurea/farmacología , Pronóstico , Proteínas de Unión al ARN/genética , Sorafenib , Adulto JovenRESUMEN
Cardiac allograft vasculopathy (CAV) was the leading cause of late death in heart transplantation recipients. Matrix metalloproteinase-14 (MMP-14), as a member of the MMPs family, has been reported to play a vital role in coronary vascular lesions of allotransplanted hearts. However, concrete mechanism is still unclear. Herein, we showed that the expression of MMP-14 was different between isografts and allografts. Interestingly, we found MMP-14 could interact with CD44 in allografts. Cluster of differentiation 44 (CD44), as a cell adhesion receptor and is involved in cell migration, caused our interest in MMP-14/CD44 complex in allografts. Then we analyzed the effect of MMP-14/CD44 complex on pro-MMP-9 activation and vascular smooth muscle cell (VSMC) migration in rat VSMC TNF-α treated model. Then, we further found intervention of MMP-14/CD44 complex could inhibit VSMC migration. Our results elucidate the molecular mechanism of VSMC migration after cardiac transplantation and provide theoretical basis for seeking new specific drug targets for CAV prevention and treatment.
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Movimiento Celular/fisiología , Trasplante de Corazón , Receptores de Hialuranos/metabolismo , Metaloproteinasa 14 de la Matriz/metabolismo , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Regulación hacia Arriba , Aloinjertos , Animales , Isoinjertos , Masculino , Músculo Liso Vascular/patología , Miocardio/metabolismo , Miocardio/patología , Miocitos del Músculo Liso/patología , Ratas , Ratas Endogámicas Lew , Ratas Wistar , Serina Endopeptidasas/metabolismoRESUMEN
BACKGROUND: Cardiac allograft vasculopathy (CAV) decreases the long-term survival of heart transplantation recipients. Vascular smooth muscle cell (VSMC) apoptosis is an important pathological feature of CAV. Erythroblast transformation-specific 2 (Ets-2), as a transcription factor, participates in cell apoptosis and plays an important role in organ transplantation. METHODS: Hearts from Wistar-Furth (WF:RT1u) rats were heterotopically transplanted into Lewis (Lew:RT1(l)) rats without immunosuppression. Additional syngeneic heterotopic cardiac transplantations were performed in Lewis rats. HE staining was used to identify CAV. Ets-2 expression was examined by western blot. Ets-2 tissue location was examined by immunohistochemical assay and double immunostaining. Cleaved caspase 3 expression was detected by western blot. Co-localization of Ets-2 and cleaved caspase 3 was detected by double immunostaining. Ets-2, p53, cleaved caspase 3 and Bcl-xl expression in rat VSMC line A7R5 was examined after Ets-2 siRNA transfection. TUNEL assay was applied to detect A7R5 apoptosis with or without ETS-2 siRNA transfection. Immunoprecipitation was performed to explore the interaction between Ets-2 and p53. RESULTS: Ets-2 expression decreased in the allograft group but had no obvious change in the isograft group. Meanwhile, the phenomenon of CAV was observed in the allograft group and there is neointima formation in the isograft group which is not obvious compared with allograft group. Additionally, Ets-2 expression was opposite to VSMC apoptosis in the allograft group. In vitro, Ets-2 siRNA transfection in A7R5cells resulted in enhanced cell apoptosis. Finally, Ets-2 interacted with p53. CONCLUSIONS: Ets-2 might inhibit VSMC apoptosis via p53 pathway. The results further elucidate the molecular mechanism of VSMC apoptosis after heart transplantation during CAV and provide theoretical basis for seeking new specific drug targets for CAV prevention and treatment.
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Irreversible damage of cardiac function arisen from myocardial ischemia/reperfusion injury (MIRI) leads to an emerging challenge in the treatments of cardiac ischemic diseases. Molecular chaperone heat shock protein 70 (HSP70) attenuates heat-stimulated cell autophagy, apoptosis, and damage in the heart. Under specific conditions, autophagy may, directly or indirectly, induce cell death including necroptosis. Whether HSP70 inhibits cardiomyocyte necroptosis via suppressing autophagy during MIRI is unknown. In our study, HSP70 expression was opposite to necroptosis marker RIP1 and autophagy marker LC3A/B expression after myocardial ischemia/reperfusion (MIR) in vivo. Furthermore, in vitro primary rat cardiomyocytes mimicked MIRI by hypoxia/reoxygenation (H/R) treatment. Knockdown of HSP70 expression promoted cardiomyocyte autophagy and necroptosis following H/R treatment, while the increase tendency was downregulated by autophagy inhibitor 3-MA, showing that autophagy-induced necroptosis could be suppressed by HSP70. In summary, HSP70 downregulates cardiomyocyte necroptosis through suppressing autophagy during myocardial IR, revealing the novel protective mechanism of HSP70 and supplying a novel molecular target for the treatment of heart ischemic diseases.
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Proteínas HSP70 de Choque Térmico/fisiología , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/patología , Animales , Autofagia/fisiología , Hipoxia de la Célula , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Proteínas HSP70 de Choque Térmico/antagonistas & inhibidores , Proteínas HSP70 de Choque Térmico/genética , Inmunohistoquímica , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Miocitos Cardíacos/metabolismo , Necrosis/fisiopatología , Proteínas Serina-Treonina Quinasas , Ratas , Ratas Sprague-Dawley , Proteína Serina-Treonina Quinasas de Interacción con ReceptoresRESUMEN
The receptor for activated C kinase 1 (RACK1) is a multifaceted scaffolding protein that mediates the shuttling of activated protein kinase C (PKC) to cellular membranes. In addition, RACK1 could decrease cell apoptosis in a variety of disease models. However, the function of RACK1 in cardiomyocyte apoptosis after myocardial ischemia/reperfusion (I/R) is unknown. In this study, male Sprague-Dawley rats were anesthetized and subjected to myocardial I/R insult consisting of 30 min left anterior descending coronary artery (LAD) occlusion followed by reperfusion for 1, 2, 4, 6, 8, 12, and 24 h. The expression of RACK1 was decreased after myocardial I/R and was associated with cardiomyocyte apoptosis. To further verify the relationship between RACK1 and cardiomyocyte apoptosis, H9c2 cardiomyocytes were cultured under hypoxia for 6 h, then maintained in the regular incubator to reoxygenation. After H9c2 cells were transfected with Flag-RACK1 to overexpress RACK1, RACK1 expression was upregulated in hypoxia/reoxygenation (H/R) 4 h group accompanied with the decrease of cleaved caspase-3 and the increase of Bcl-2 expression. Terminal transferase-mediated biotin dUTP nick end labeling (TUNEL) assay showed that RACK1 overexpression inhibited H9c2 cell apoptosis induced by H/R treatment. Our data suggested that RACK1 might suppress cardiomyocyte apoptosis after I/R, providing a novel molecular target for the therapy of ischemia heart disease.
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Apoptosis/fisiología , Cardiotónicos/metabolismo , Proteínas de Unión al GTP/metabolismo , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/metabolismo , Animales , Caspasa 3/metabolismo , Células Cultivadas , Regulación hacia Abajo , Etiquetado Corte-Fin in Situ , Masculino , Infarto del Miocardio/patología , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Cinasa C ActivadaRESUMEN
Cardiomyocyte apoptosis, which occurs during ischemia and reperfusion injury, can cause irreversible damage to cardiac function. There is accumulating evidence that nuclear factor 45 (NF45) and regulatory pathways are important in understanding reparative processes in the myocardium. NF45 is a multifunctional regulator of gene expression that participates in the regulation of DNA break repair. Recently, NF45 has been proved to be associated with tumor cell apoptosis in various human malignancies. However, the underlying mechanism of NF45 regulating myocardial ischemia-reperfusion (I/R) injury remains unclear. In this study, western blot showed that NF45 expression decreased after myocardial I/R in vivo. Double immunofluorescent staining revealed that NF45, located in the nucleus of cardiomyocyes, was correlated with cardiomyocyte apoptosis. Furthermore, NF45 expression decreased in H9c2 cells after hypoxia-reoxygenation (H/R) treatment in vitro, which was in line with the results in vivo. Overexpression of NF45 in H9c2 cells reduced cell apoptosis, as evidenced by increased Bcl-2 level, as well as decreased cleaved caspase-3, p53 and p21 expression. The expression of NF45 was reduced by LY294002 (a PI3K/Akt inhibitor), but not SB203580 (a p38 inhibitor), suggesting that NF45 prevented H/R-induced H9c2 cell apoptosis via PI3K/Akt pathway. Our data may supply a novel molecular target for acute myocardial infarction (AMI) therapy.
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Apoptosis/fisiología , Isquemia Miocárdica/patología , Miocitos Cardíacos/patología , Proteína del Factor Nuclear 45/metabolismo , Daño por Reperfusión/patología , Animales , Western Blotting , Modelos Animales de Enfermedad , Inmunohistoquímica , Masculino , Isquemia Miocárdica/metabolismo , Miocitos Cardíacos/metabolismo , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/metabolismoRESUMEN
Cardiomyocytes apoptosis following reperfusion injury causes irreversible damage to cardiac function. Understanding the mechanisms underlying cardiomyocytes death under these conditions can be helpful to identify strategies to abrogate such detrimental effects. Stem cell-specific proteins and regulatory pathways become important in understanding reparative processes in the myocardium. One such regulatory protein named nucleostemin (NS) has vital roles in cardiac ischemia. Although the relationship between NS and cell apoptosis has been studied, it is unknown how NS is controlled and how it participates in cardiomyocytes apoptosis induced by ischemia reperfusion (I/R). In the present study, we aimed to investigate the direct role of NS in myocardial I/R. In vivo, NS was highly expressed in cardiac tissues after I/R. Double immunofluorescent staining showed that NS located in the nucleolar of cardiomyocytes and correlated with cardiomyocytes apoptosis. Furthermore, in vitro primary rat cardiomyocytes increased NS expression induced by hypoxia-reoxygenation (H/R) treatment, in line with results in vivo. Suppression of NS expression by siNS promoted the expression of terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL)-positive cells p53 and cleaved caspase-3, which demonstrates I/R may require increased expression of NS to suppress p53 activation and maintain cardiomyocytes survival.
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Apoptosis/fisiología , Proteínas Portadoras/metabolismo , Daño por Reperfusión Miocárdica/patología , Miocardio/patología , Proteínas Nucleares/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Apoptosis/genética , Procedimientos Quirúrgicos Cardíacos , Proteínas Portadoras/genética , Caspasa 3/biosíntesis , Células Cultivadas , Proteínas de Unión al GTP , Etiquetado Corte-Fin in Situ , Miocitos Cardíacos/metabolismo , Proteínas Nucleares/genética , Interferencia de ARN , ARN Interferente Pequeño/genética , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Transducción de Señal/fisiología , Proteína p53 Supresora de Tumor/biosíntesisRESUMEN
Acute allograft rejection is initiated by a large number of recipient T cells that recognize donor alloantigens. Apoptotic signals trigger Nur77 production. Nur77 translocates from the nucleus to the mitochondria to induce a loss of mitochondrial membrane potential and the release of mitochondrial cell-death mediators, including HtrA2/Omi. In this study, we investigated the relationship between Nur77, HtrA2/Omi, and T lymphocyte apoptosis during acute allograft rejection in a rat cardiac transplantation model. The median survival time of the isograft group was longer than that of the allograft group. The cardiac grafts in isogenic (Lewis to Lewis) and allogenic (Wistar to Lewis) models were subjected to HE stain, showing that no rejection occurred in the isografts and that the rejection level was increased in allografts. Compared with the rare expression in syngeneic Lewis rat hearts by western blot analysis, Nur77 protein level in allograft increased from day 1, peaked at day 5 after transplantation, and maintained the highest level until day 7. Double immunofluorescence staining on allograft tissues at day 5 showed Nur77 immunocompetence in most CD3(+) cells, and Nur77 positive T cells also showed HtrA2/Omi-positive signal. Meanwhile, active caspase-3 was apparent in these HtrA2/Omi-positive T cells. Immunohistochemical results suggested that both Nur77 and active caspase-3 were expressed in increasing infiltrating lymphocytes. Our results demonstrated that upregulated Nur77 may promote graft-infiltrating T lymphocyte apoptosis by translocating and inducing HtrA2/Omi release from mitochondria in acute rejection after cardiac transplantation.