cytochrome-c-t and Cardiomegaly

Metabolic disorders often lead to cardiac complications. Metabolic deregulations during diabetic conditions are linked to mitochondrial dysfunctions, which are the key contributing factors in cardiac hypertrophy. However, the underlying mechanisms involved in diabetes-induced cardiac hypertrophy are poorly understood. In the current study, we initially established a diabetic rat model by alloxan-administration, which was validated by peripheral glucose measurement. Diabetic rats displayed myocardial stiffness and fibrosis, changes in heart weight/body weight, heart weight/tibia length ratios, and enhanced size of myocytes, which altogether demonstrated the establishment of diabetic cardiac hypertrophy (DCH). Furthermore, we examined the expression of genes associated with mitochondrial signaling impairment. Our data show that the expression of PGC-1α, cytochrome c, MFN-2, and Drp-1 was deregulated. Mitochondrial-signaling impairment was further validated by redox-system dysregulation, which showed a significant increase in ROS and thiobarbituric acid reactive substances, both in serum and heart tissue, whereas the superoxide dismutase, catalase, and glutathione levels were decreased. Additionally, the expression levels of pro-apoptotic gene PUMA and stress marker GATA-4 genes were elevated, whereas ARC, PPARα, and Bcl-2 expression levels were decreased in the heart tissues of diabetic rats. Importantly, these alloxan-induced impairments were rescued by N-acetyl cysteine, ascorbic acid, and selenium treatment. This was demonstrated by the amelioration of myocardial stiffness, fibrosis, mitochondrial gene expression, lipid profile, restoration of myocyte size, reduced oxidative stress, and the activation of enzymes associated with antioxidant activities. Altogether, these data indicate that the improvement of mitochondrial dysfunction by protective agents such as N-acetyl cysteine, selenium, and ascorbic acid could rescue diabetes-associated cardiac complications, including DCH.

Topics: Acetylcysteine; Animals; Antioxidants; Apoptosis; Apoptosis Regulatory Proteins; Ascorbic Acid; Biomarkers; Blood Glucose; Body Weight; Calcium; Cardiomegaly; Cardiotonic Agents; Cytochromes c; Diabetic Cardiomyopathies; Disease Models, Animal; Down-Regulation; GATA4 Transcription Factor; Lipid Peroxidation; Lipids; Mitochondria, Heart; Myocardium; Oxidation-Reduction; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; PPAR alpha; Rats, Sprague-Dawley; Reactive Oxygen Species; RNA, Messenger; Selenium

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and β-myosin heavy chain. Taurine also reduced ROS, intracellular Ca

Topics: Animals; Apoptosis; Apoptotic Protease-Activating Factor 1; Atrial Natriuretic Factor; bcl-2-Associated X Protein; Calcium; Calcium-Binding Proteins; Calpain; Cardiomegaly; Caspase 3; Caspase 9; Cell Line; Cytochromes c; Isoproterenol; Membrane Potential, Mitochondrial; Mitochondria; Myocytes, Cardiac; Natriuretic Peptide, Brain; Natriuretic Peptides; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Rats; Taurine; Ventricular Myosins

Herein, we investigated the effects of B. diffusa (BDE), a well-known cardiotonic edible medicinal plant against apoptosis in Angiotensin II (Ang II)-stimulated hypertrophic cardiac cells (H9c2). The cells were analyzed for viability, markers of hypertrophy, apoptosis, and the expression of various proteins related to apoptosis. Ang II (100 nM for 48 h)-exposed H9c2 cells treated with BDE (75 μg/ml) showed a significant reduction in apoptosis (58.60%↓) compared to Ang II-alone treated cells. BDE treatment significantly reduced the up-regulation of Bax and cytosolic cytochrome-C caused by Ang II as well as reduced the degree of Ang II- induced down-regulation of Bcl-2. A reduction in caspase-3 activity (33.77%↓) and down-regulation of TNF-α was also observed in BDE treated cells stimulated with Ang II. Furthermore, the up-regulation of phospho-p38 MAPK was attenuated by BDE treatment. Bioactive components in the extract were identified as boeravinone B, quercetin, kaempferol, and caffeic acid as evident from high-performance liquid chromatography (HPLC). Overall, our study shows that B. diffusa is effective in attenuating apoptosis in cardiac cells, which is a major contributor to sudden cardiac death in addition to its nutraceutical properties.

Topics: Angiotensin II; Animals; Apoptosis; bcl-2-Associated X Protein; Biomarkers; Cardiomegaly; Caspases; Cell Survival; Cytochromes c; Interleukin-10; Nyctaginaceae; p38 Mitogen-Activated Protein Kinases; Phenols; Plant Extracts; Rats; RNA, Messenger; Staining and Labeling; Tumor Necrosis Factor-alpha

Cardiomyocyte apoptosis acts as a prime modulator of cardiac hypertrophy leading to heart failure, a major cause of human mortality worldwide. Recent therapeutic interventions have focussed on translational applications of diverse pharmaceutical regimes among which, Curcumin (from Curcuma longa) is known to have an anti-hypertrophic potential but with limited pharmacological efficacies due to low aqueous solubility and poor bioavailability. In this study, Curcumin encapsulated by carboxymethyl chitosan (CMC) nanoparticle conjugated to a myocyte specific homing peptide was successfully delivered in bioactive form to pathological myocardium for effective regression of cardiac hypertrophy in a rat (Rattus norvegicus) model. Targeted nanotization showed higher cardiac bioavailability of Curcumin at a low dose of 5 mg/kg body weight compared to free Curcumin at 35 mg/kg body weight. Moreover, Curcumin/CMC-peptide treatment during hypertrophy significantly improved cardiac function by downregulating expression of hypertrophy marker genes (ANF, β-MHC), apoptotic mediators (Bax, Cytochrome-c) and activity of apoptotic markers (Caspase 3 and PARP); whereas free Curcumin in much higher dose showed minimal improvement during compromised cardiac function. Targeted Curcumin treatment significantly lowered p53 expression and activation in diseased myocardium via inhibited interaction of p53 with p300-HAT. Thus attenuated acetylation of p53 facilitated p53 ubiquitination and reduced the apoptotic load in hypertrophied cardiomyocytes; thereby limiting cardiomyocytes' need to enter the regeneration cycle during hypertrophy. This study elucidates for the first time an efficient targeted delivery regimen for Curcumin and also attributes towards probable mechanistic insight into its therapeutic potential as a cardio-protective agent for regression of cardiac hypertrophy.

Topics: Acetylation; Animals; Apoptosis; bcl-2-Associated X Protein; Biological Availability; Cardiomegaly; Caspase 3; Cell Survival; Chitosan; Curcumin; Cytochromes c; Disease Models, Animal; Dose-Response Relationship, Drug; Down-Regulation; Drug Delivery Systems; E1A-Associated p300 Protein; Myocardium; Myocytes, Cardiac; Nanoparticles; Rats; Rats, Wistar; Tumor Suppressor Protein p53

Oxidative stress is a crucial factor inducing cardiomyocyte apoptosis due to cardiac hypertrophy. Additional evidence has revealed that H2S plays an antioxidant role and is cytoprotective. Hence, we aimed to elucidate whether H2S prevents cardiomyocyte apoptosis due to cardiac hypertrophy via its antioxidant function. The cardiac hypertrophy model was obtained by injecting a high dose of isoproterenol (ISO) subcutaneously, and the hemodynamic parameters were measured in groups that received either ISO or ISO with the treatment of NaHS. TUNEL (terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling) and EM (electron microscopy) experiments were performed to determine the occurrence of apoptosis in heart tissues. The expression of caspase-3 protein in the cytoplasm and NADPH oxidase 4 (NOX4), and cytochrome c (cyt c) proteins in the mitochondria were analyzed using Western blotting. In contrast, to determine whether ISO-induced apoptosis in the cultured cardiomyocytes may be related to oxidative stress, JC-1 and MitoSOX assays were performed to detect the mitochondrial membrane potential and reactive oxygen species (ROS) production in the mitochondria. Exogenous H2S was found to ameliorate cardiac function. The histological observations obtained from TUNEL and EM demonstrated that treatment with NaHS inhibited the occurrence of cardiac apoptosis and improved cardiac structure. Moreover, H2S reduced the expression of the cleaved caspase-3, NOX4 and the leakage of cyt c from the mitochondria to the cytoplasm. We also observed that exogenous H2S could maintain the mitochondrial membrane potential and reduce ROS production in the mitochondria. Therefore, H2S reduces oxidative stress due to cardiac hypertrophy through the cardiac mitochondrial pathway.

Topics: Animals; Animals, Newborn; Apoptosis; Benzimidazoles; Carbocyanines; Cardiomegaly; Cardiotonic Agents; Caspase 3; Cytochromes c; Fluorescein-5-isothiocyanate; Fluorescence; Heart Function Tests; Heart Ventricles; Hemodynamics; Hydrogen Sulfide; In Situ Nick-End Labeling; Isoproterenol; Male; Membrane Potential, Mitochondrial; Mitochondria, Heart; Myocardium; Myocytes, Cardiac; NADPH Oxidase 4; NADPH Oxidases; Phenanthridines; Rats; Rats, Wistar; Reactive Oxygen Species

Alterations in calcium homeostasis in the intracellular endo/sarcoplasmic reticulum (ER/SR) and mitochondria of cardiomyocytes cause cell death via the SR and mitochondrial apoptotic pathway, contributing to ventricular dysfunction. However, the role of the calcium-sensing receptor (CaR) in cardiac hypertrophy and heart failure has not been studied. This study examined the possible involvement of CaR in the SR and mitochondrial apoptotic pathway in an experimental model of heart failure.. In Wistar rats, cardiac hypertrophy and heart failure were induced by subcutaneous injection of isoproterenol (Iso). Calindol, an activator of CaR, and calhex231, an inhibitor of CaR, were administered by caudal vein injection. Cardiac remodeling and left ventricular function were then analyzed in these rats. After 2, 4, 6 and 8 weeks after the administration of Iso, the rats developed cardiac hypertrophy and failure. The cardiac expression of ER chaperones and related apoptotic proteins was significantly increased in the failing hearts. Furthermore, the expression of ER chaperones and the apoptotic rate were also increased with the administration of calindol, whereas the expression of these proteins was reduced with the treatment of calhex231. We also induced cardiac hypertrophy and failure via thoracic aorta constriction (TAC) in mice. After 2 and 4 weeks of TAC, the expression of ER chaperones and apoptotic proteins were increased in the mouse hearts. Furthermore, Iso induced ER stress and apoptosis in cultured cardiomyocytes, while pretreatment with calhex231 prevented ER stress and protected the myocytes against apoptosis. To further investigate the effect of CaR on the concentration of intracellular calcium, the calcium concentration in the SR and mitochondria was determined with Fluo-5N and x-rhod-1 and the mitochondrial membrane potential was examined with JC-1 using laser confocal microscopy. After treatment with Iso for 48 hours, activation of CaR reduced [Ca(2+)]SR, increased [Ca(2+)]m, decreased the mitochondrial membrane potential, increased the expression of ER stress chaperones and related apoptotic proteins, and induced the release of cytochrome c from the mitochondria.. Our results demonstrated that CaR activation caused Ca(2+) release from the SR into the mitochondria and induced cardiomyocyte apoptosis through the SR and mitochondrial apoptotic pathway in failing hearts.

Topics: Animals; Aorta, Thoracic; Apoptosis; Benzamides; Calcium; Cardiomegaly; Cyclohexylamines; Cytochromes c; Heart Failure; Indoles; Inositol 1,4,5-Trisphosphate Receptors; Isoproterenol; Male; Membrane Potential, Mitochondrial; Mitochondria; Molecular Chaperones; Myocytes, Cardiac; Naphthalenes; Rats; Rats, Wistar; Receptors, Calcium-Sensing; Sarcoplasmic Reticulum

The cysteine protease cathepsin K has been implicated in pathogenesis of cardiovascular disease. We hypothesized that ablation of cathepsin K protects against obesity-associated cardiac dysfunction. Wild-type mice fed a high-fat diet exhibited elevated heart weight, enlarged cardiomyocytes, increased left ventricular wall thickness, and decreased fractional shortening. All these changes were reconciled in cathepsin K knockout mice. Cathepsin K knockout partly reversed the impaired cardiomyocyte contractility and dysregulated calcium handling associated with high-fat diet. Additionally, cathepsin K knockout alleviated whole-body glucose intolerance and improved insulin-stimulated Akt phosphorylation in high-fat diet-fed mice. High-fat feeding increased the expression of cardiac hypertrophic proteins and apoptotic markers, which were inhibited by cathepsin K knockout. Furthermore, high-fat feeding resulted in cathepsin K release from lysosomes into the cytoplasm. In H9c2 myoblasts, silencing of cathepsin K inhibited palmitic acid-induced release of cytochrome c from mitochondria and expression of proapoptotic signaling molecules. Collectively, our data indicate that cathepsin K contributes to the development of obesity-associated cardiac hypertrophy and may represent a potential target for the treatment to obesity-associated cardiac anomalies.

Topics: Animals; Apoptosis; Calcium; Cardiomegaly; Cathepsin K; Cell Line; Cytochromes c; Cytoplasm; Diet, High-Fat; Enzyme Inhibitors; Gene Silencing; Glucose Intolerance; Hypoglycemic Agents; Insulin; Lysosomes; Male; Mice; Mice, Knockout; Mitochondria; Myocardial Contraction; Myocytes, Cardiac; Obesity; Palmitic Acid; Phosphorylation; Proto-Oncogene Proteins c-akt; Ventricular Remodeling

Increased myocyte apoptosis in diabetic hearts has been previously reported. Therefore, the purpose of this study was to evaluate the effects of insulin on cardiac apoptotic, hypertrophic, and survival pathways in streptozotocin (STZ)-induced diabetic rats. Forty-eight male Wistar rats at 8 weeks of age were randomly divided into control group (Control), STZ-induced (65 mg/kg STZ i.v.) Type 1-like diabetic rats (DM), and DM rats with 4 IU insulin replacement (DI) for 4 and 8 weeks, respectively. The levels of protein involved in cardiac apoptotic, hypertrophic, and survival pathways were measured by Western blotting. Cardiac mitochondrial-dependent apoptotic pathways, such as Bad, cytosolic cytochrome c, activated caspase 9 and 3, and calcineurin-nuclear factor activation transcription 3 (NFAT3) hypertrophic pathway in DM were increased compared to Control and attenuated in DI group after 8 weeks whereas those were not found after 4 weeks. Cardiac anti-apoptotic Bcl2 and phosphorylated-Bad were significantly decreased in DM group but not in DI group after 8 weeks. Insulin-like growth factor-I receptor (IGFIR), phosphatidylinositol 3'-kinase (PI3K), and the protein kinase B (Akt) were significantly decreased in DM relative to Control and DI after 8 weeks whereas those were not found after 4 weeks. Insulin replacement not only prevents activation of the cardiac mitochondrial-dependent apoptotic pathway and calcineurin-related NFAT3 hypertrophic pathway in diabetes but it also enhances the cardiac insulin/IGFIR-PI3K-Akt survival pathway, all of which are attenuated with insulin therapeutic duration-dependent manners. The findings may provide possible diabetes-related apoptotic, hypertrophic, and survival pathways for potentially preventing cardiac abnormality in diabetes.

Topics: Animals; Apoptosis; bcl-Associated Death Protein; Body Weight; Calcineurin; Cardiomegaly; Caspase 3; Caspase 9; Cell Survival; Cytochromes c; Diabetes Mellitus, Experimental; Enzyme Activation; Insulin; Mitochondria; Models, Biological; Myocardium; NFATC Transcription Factors; Organ Size; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Receptor, IGF Type 1; Streptozocin

In spite of opposing changes in rates of adenosine triphosphate turnover, hypertrophy and atrophy of the heart are accompanied by the same changes in gene expression, resembling a fetal genotype. Fetal hearts are characterized by increased ischemia tolerance. We assessed respiratory capacity of mitochondrial subpopulations from unloaded and pressure-overloaded hearts before and after 15 minutes of normothermic ischemia. Unloading was achieved by heterotopic rat heart transplantation and overloading by aortic banding. Respiratory chain gene expression (NADH dehydrogenase, cytochrome c oxidase [COX]) were analyzed by reverse transcriptase-polymerase chain reaction. Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) were isolated by differential centrifugation. Citrate synthase was used as mitochondrial marker enzyme. Adenosine diphosphate-stimulated oxygen consumption (state 3) was measured with a Clark-type electrode. Unloading resulted in atrophy, overloading in hypertrophy. State 3 was reduced in atrophied hearts both in SSM and IFM (SSM: 204 +/- 79 vs 804 +/- 147 natoms oxygen min(-1) mL(-1), P < .001; IFM: 468 +/- 158 vs 1141 +/- 296 natoms oxygen min(-1) mL(-1), P < .05), but was unchanged in hypertrophied hearts. NADH dehydrogenase and COX expression was also decreased with atrophy and was unchanged with hypertrophy. Ischemia caused decreased recovery of citrate synthase in isolates of SSM (P < .05) but not of IFM. State 3 in control hearts was reduced in IFM (-41%, P < .01) and SSM (-19%, not significant). This ischemia-induced decrease was less pronounced in SSM (-2%) and IFM (-22%) of atrophied and IFM (-23%) of hypertrophied hearts. Subsarcolemmal mitochondria of hypertrophied hearts displayed the greatest ischemia-induced decrease of state 3 (-32%, P < .05). In conclusion, (1) long-term changes in workload differentially affect maximal respiratory capacity and ischemia tolerance of isolated mitochondria. The changes are not parallel to the changes in energy requirements. (2) Mitochondria of atrophied hearts appear to be more resistant against ischemia than controls.

Topics: Adenosine Diphosphate; Animals; Atrophy; Body Weight; Cardiomegaly; Citrate (si)-Synthase; Cytochromes c; Electron Transport; Gene Expression Regulation, Enzymologic; Heart Diseases; In Vitro Techniques; Male; Mitochondria, Heart; Muscle Proteins; Myocardial Ischemia; Myocardial Reperfusion Injury; NADH Dehydrogenase; Organ Size; Oxygen Consumption; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction

Iron deficiency is associated with multiple health problems, including the cardiovascular system. However, the mechanism of action of iron-deficiency-induced cardiovascular damage is unclear. The aim of the present study was to examine the effect of dietary iron deficiency on cardiac ultrastructure, mitochondrial cytochrome c release, NOS (nitric oxide synthase) and several stress-related protein molecules, including protein nitrotyrosine, the p47phox subunit of NADPH oxidase, caveolin-1 and RhoA. Male weanling rats were fed with either control or iron-deficient diets for 12 weeks. Cardiac ultrastructure was examined by transmission electron microscopy. Western blot analysis was used to evaluate cytochrome c, endothelial and inducible NOS, NADPH oxidase, caveolin-1 and RhoA. Protein nitrotyrosine formation was measured by ELISA. Rats fed an iron-deficient diet exhibited increased heart weight and size compared with the control group. Heart width, length and ventricular free wall thickness were similar between the two groups. However, the left ventricular dimension and chamber volume were significantly enhanced in the iron-deficient group compared with controls. Ultrastructural examination revealed mitochondrial swelling and abnormal sarcomere structure in iron-deficient ventricular tissues. Cytochrome c release was significantly enhanced in iron-deficient rats. Protein expression of eNOS (endothelial NOS) and iNOS (inducible NOS), and protein nitrotyrosine formation were significantly elevated in cardiac tissue or mitochondrial extraction from the iron-deficient group. Significantly up-regulated NADPH oxidase, caveolin-1 and RhoA expression were also detected in ventricular tissue of the iron-deficient group. Taken together, these results suggest that dietary iron deficiency may have induced cardiac hypertrophy characterized by aberrant mitochondrial and irregular sarcomere organization, which was accompanied by increased reactive nitrogen species and RhoA expression.

Topics: Animals; Body Weight; Cardiomegaly; Cytochromes c; Heart Ventricles; Heat-Shock Proteins; Iron Deficiencies; Male; Microscopy, Electron; Mitochondria, Heart; Myocardium; Myocytes, Cardiac; Nitric Oxide Synthase; Organ Size; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Tyrosine