Project description:Early reperfusion of ischemic cardiac tissue remains the most effective intervention for improving clinical outcome following myocardial infarction. However, abrupt increases in intracellular Ca2+ during myocardial reperfusion cause cardiomyocyte death and consequent loss of cardiac function, referred to as ischemia/reperfusion (IR) injury. Cardiac IR is accompanied by dynamic changes in expression of microRNAs (miRNAs), which inhibit specific mRNA targets. miR-214 is up-regulated during ischemic injury and heart failure in mice and humans, but its potential role in these processes is unknown. We show that genetic deletion of miR-214 in mice causes loss of cardiac contractility, increased apoptosis, and excessive fibrosis in response to IR injury. The microarray contains 6 samples, each containing cDNA pooled from 3 mice per group. There are no replicates. The array was designed to make 3 different pairwise comparisons between the following: P14 WT and miR-214 KO hearts; adult WT and miR-214 KO skeletal muscle; adult WT and miR-214 KO hearts
Project description:Early reperfusion of ischemic cardiac tissue remains the most effective intervention for improving clinical outcome following myocardial infarction. However, abrupt increases in intracellular Ca2+ during myocardial reperfusion cause cardiomyocyte death and consequent loss of cardiac function, referred to as ischemia/reperfusion (IR) injury. Cardiac IR is accompanied by dynamic changes in expression of microRNAs (miRNAs), which inhibit specific mRNA targets. miR-214 is up-regulated during ischemic injury and heart failure in mice and humans, but its potential role in these processes is unknown. We show that genetic deletion of miR-214 in mice causes loss of cardiac contractility, increased apoptosis, and excessive fibrosis in response to IR injury.
Project description:Ischemic preconditioning is effective in limiting subsequent ischemic acute kidney injury in experimental models. microRNAs are an important class of post-transcriptional regulator and show promise as biomarkers of kidney injury. An evaluation was performed of the time- and dose-dependent effects of ischemic preconditioning in a rat model of functional (bilateral) ischemia-reperfusion injury. A short, repetitive sequence of ischemic preconditioning resulted in optimal protection from subsequent ischemia-reperfusion injury. A detailed characterization of microRNA expression in ischemic preconditioning/ischemia-reperfusion injury was performed by small RNA-Seq.
Project description:Ischemic preconditioning is effective in limiting subsequent ischemic acute kidney injury in experimental models. microRNAs are an important class of post-transcriptional regulator and show promise as biomarkers of kidney injury. An evaluation was performed of the time- and dose-dependent effects of ischemic preconditioning in a rat model of functional (bilateral) ischemia-reperfusion injury. A short, repetitive sequence of ischemic preconditioning resulted in optimal protection from subsequent ischemia-reperfusion injury. A detailed characterization of microRNA expression in ischemic preconditioning/ischemia-reperfusion injury was performed by Exiqon miRCURY microRNA array.
Project description:Heart disease remains the leading cause of death globally. Although reperfusion following myocardial ischemia can prevent death by restoring nutrient flow, ischemia/reperfusion injury can cause significant heart damage. The mechanisms that drive ischemia/reperfusion injury are not well understood; currently, few methods can predict the state of the cardiac muscle cell and its metabolic conditions during ischemia. Here, we explored the energetic sustainability of cardiomyocytes, using a model for cellular metabolism to predict the levels of ATP following hypoxia. We modeled glycolytic metabolism with a system of coupled ordinary differential equations describing the individual metabolic reactions within the cardiomyocyte over time. Reduced oxygen levels and ATP consumption rates were simulated to characterize metabolite responses to ischemia. By tracking biochemical species within the cell, our model enables prediction of the cell’s condition up to the moment of reperfusion. The simulations revealed a distinct transition between energetically sustainable and unsustainable ATP concentrations for various energetic demands. Our model illustrates how even low oxygen concentrations allow the cell to perform essential functions. We found that the oxygen level required for a sustainable level of ATP increases roughly linearly with the ATP consumption rate. An extracellular O2 concentration of ~0.007 mM could supply basic energy needs in non-beating cardiomyocytes, suggesting that increased collateral circulation may provide an important source of oxygen to sustain the cardiomyocyte during extended ischemia. Our model provides a time-dependent framework for studying various intervention strategies to change the outcome of reperfusion.
Project description:Restoration of blood flow is the definitive therapy to salvage myocardium following ischemic injury. However, sudden restoration of blood flow to the ischemic myocardium causes ischemia reperfusion injury (IRI). Here, the cardioprotective effect of remote ischemic postconditioning (RPostC) was investigated, based on our in vitro rat model of myocardial IRI. Three groups, including Sham, IRI, and IRI+ RPostC, were utilized for the analysis of Affymetrix Rat Gene 2.0 ST chip.
Project description:The management of cardiac ischemic injury has been challenged by ischemia and reperfusion (I/R) injury. Reactive oxygen species (ROS) generated from mitochondrial reverse electron transport (RET) during the early phase of reperfusion is considered to be the initiating cause for ischemia and reperfusion injury. Ginsenosides and their prescriptions are widely used in the clinic for treatment of myocardial ischemia, however, the action to combat ROS remains to be elucidated. In this work, we used TMT-based proteomic approach to detect differential proteins from mitochondrial fractions of mice hearts with ischemia-reperfusion. Results indicated that the mass error of identified peptides was within 10 ppm, and most of the identified peptides were composed of 7-23 amino acids. Using these qualified data, 17,262 peptides, with a confidence level ≥ 95%, were mapped to 3,054 protein groups. PCA analysis showed that the model group was clearly separated from the blank group, while the protein pattern was partly reversed with Rb1 treatment. With a criteria of p-value < 0.05, 591 significantly changed proteins including 186 increased and 405 decreased ones in the model group were identified compared with the blank group. These proteins were divided into 4 clusters. Proteins in Cluster I highly increased in the model group, but clearly decreased in the Rb1 group. Proteins in Cluster IV clearly decreased in the model group, but markedly increased in the Rb1 group. Proteins in Cluster III and in Cluster IV were not significantly or slightly regulated by the Rb1 treatment. GO analysis of Cluster I and II indicated that the molecular function of these proteins were closely related to oxidoreductase activity and NADH dehydrogenase activity. Our result showed that Rb1 administration before ischemia markedly decreased infarct size (48 h post-I/R), and preserved cardiac function (2 weeks post-I/R), and subsequently limited tissue fibrosis (28 days post-I/R). These results indicated that targeted inhibition of mitochondrial complex I in the early stage of reperfusion by Rb1 is a potential therapeutic strategy for alleviating IR injury. This work not only indicates a potent molecular target for the precision therapy of myocardial ischemia by Rb1, but also provides novel knowledge for the management of cardiac ischemic injury by traditional Chinese medicine.
Project description:Cardiac remodeling is the primary factor for the development of ischemic heart failure, which can result from various cardiomyopathies. Pyruvate Dehydrogenase Kinase1 (PDK1) is one of the components of AGC kinase family that maintain mitochondrial metabolism. We here report a PDK1-deficient human cardiac myocyte (CM) model that mimicked the human PDK1 homozygous frameshift mutation and determined the effects of PDK1 dysfunction and its underlying mechanism. PDK1 gene knockout did not affect the pluripotency and differentiation efficiency of hiPSCs. Myocardial cells with a PDK1 gene knockout showed abnormal metabolism, increased oxidative stress levels, decreased cell viability, and increased apoptosis. In addition, lentivirus transfection significantly improved the mitochondrial metabolism in the PDK1-deficient human myocardial model. Taken together, our data provide a PDK1-deficient human cardiomyocyte model that exhibits abnormal mitochondrial metabolism, this model represents an important tool to gain insight into the mechanism of action of metabolism disorders resulting in myocardial remodeling, elucidate the gene-phenotype relationship of PDK1 deficiency, and facilitate drug screening.
Project description:Mitochondrial Creatine Kinase 2 (Ckmt2) as a Plasma-Based Biomarker for Evaluating Reperfusion Injury in Acute Myocardial Infarction
Project description:Myocardial ischemic preconditioning (IPC) enhances myocardial resilience to ischemic injury. Myocardial stunning is a transient, reversible dysfunction, while necrosis involves irreversible cell death. The relationship between IPC, stunning, and necrosis is not well understood, requiring further molecular investigation. This study aimed to investigate the proteomic changes associated with IPC, focusing on its relationship with myocardial stunning and necrosis. A novel 13.5-minute ischemia-reperfusion (I/R) rat model was specifically chosen to induce myocardial stunning, providing a unique approach to assess IPC effects in this context. Rats underwent either IPC with two 5-minute ischemia/reperfusion cycles followed by a 13.5-minute ischemic period or the procedure without IPC (no ischemic preconditioning, NIPC). Myocardial samples were collected at early (T1) and 4-hour post-reperfusion (T2) time points for proteomic analysis. Protein levels were quantified by differential labeling using TMTpro reagents, and subsequent liquid chromatography-mass spectrometry. IPC induced upregulation of proteins involved in endocytosis and Fc gamma R-mediated phagocytosis pathways at T1, while downregulating proteins related to tissue remodeling, immune response, and coagulation at T2. Conversely, NIPC exhibited upregulation of proteins associated with tissue damage and inflammation. IPC rats demonstrated enhanced leukocyte migration, complement activation, and immune response between T1 and T2. Consistent proteomic changes were observed between T1 and T2 in IPC vs. NIPC groups, and common alterations between IPC T2 vs. T1 and NIPC T2 vs. T1 comparisons underline shared pathways in cardiac complement and coagulation cascades. Our study reveals distinct proteomic changes induced by IPC in the context of myocardial stunning and necrosis. IPC activates early protective pathways, attenuates tissue damage and inflammation, and preserves myocardial function. These findings underscore IPC's reparative potential and identify myocardial stunning as an important, transient adaptation, which may have implications for supportive clinical management in I/R.