Project description:Mitochondria-induced cell death is a vital mechanism of heart failure (HF). Thus, identification of mitochondria-related genes (Mito-RGs) based on transcriptome sequencing data of HF might provide novel diagnostic markers and therapeutic targets for HF. First, bioinformatics analysis was conducted on the GSE57338, GSE76701, GSE136547, and GSE77399 datasets in the Gene Expression Omnibus. Next, we analyzed HF-Mito differentially expressed genes (DEGs) using the protein-protein interaction (PPI) network for obtaining critical genes and exploring their functions. Subsequently, immune cell scores of the HF and normal groups were compared. The potential alteration mechanisms of the key genes were investigated by constructing a competing endogenous RNA network. Finally, we predicted potential therapeutic agents and validated the expression levels of the key genes. Twenty-three HF-Mito DEGs were acquired in the GSE57338 dataset, and the PPI network obtained four key genes, including IFIT3, XAF1, RSAD2, and MX1. According to gene set enrichment analysis, the key genes showed high enrichment in myogenesis and hypoxia. Immune cell analysis demonstrated that aDCs, B cells, and 20 other immune cell types varied between the HF and normal groups. Moreover, we observed that H19 might affect the expression of IFIT3, AXF1, and RSAD2. PCGEM1 might regulate RSAD2 expression. A total of 515 potential therapeutic drugs targeting the key genes, such as tretinoin, silicon dioxide, and bisphenol A, were acquired. Finally, IFIT3, RSAD2, and MX1 expression increased in HF samples compared with normal samples in the GSE76701 dataset, conforming to the GSE57338 dataset analysis. This work screened four key genes, namely, IFIT3, XAF1, RSAD2, and MX1, which can be further explored in subsequent studies for their specific molecular mechanisms in HF.
Project description:Rationale: Over 50% of heart failure patients have preserved, rather than reduced ejection fraction (HFpEF vs. HFrEF). Complexity of its pathophysiology and the lack of animal models hamper the development of effective therapy for HFpEF. Objective: This study was designed to investigate the metabolic mechanisms of HFpEF and test therapeutic interventions using a novel animal model. Methods and Results: By combining the age, long-term high-fat diet and desoxycorticosterone pivalate challenge in a mouse model we were able to recapture the myriad features of HFpEF. In these mice, mitochondrial hyperacetylation exacerbated while increasing ketone body availability rescued the phenotypes. The HFpEF mice exhibited overproduction of interleukin (IL)-1β/IL-18, and tissue fibrosis due to increased assembly of NLPR3 inflammasome on hyperacetylated mitochondria. Increasing β-hydroxybutyrate (β-OHB) level attenuated NLPR3 inflammasome formation and antagonized proinflammatory cytokines-triggered mitochondrial dysfunction and fibrosis. Moreover, β-OHB downregulated the acetyl-CoA pool and mitochondrial acetylation, partially via activation of citrate synthase and inhibition of fatty acid uptake. Conclusions: Therefore, we identify the interplay of mitochondrial hyperacetylation and inflammation as a key driver in HFpEF pathogenesis which can be ameliorated by promoting β-OHB abundance.
Project description:Heart failure (HF) is associated with mitochondrial dysfunction and energy metabolism impairment. MicroRNAs are implicated in the development of heart failure. However, the mitochondria enriched microRNA during heart failure remains elusive. Here, we generated a pressure overload-induced early and late stage heart failure model at 4 weeks and 8 weeks following transverse aortic constriction (TAC) in mice. We found that expression of mitochondrion protein COX4 was highly enriched in isolated mitochondria from cardiac tissues while GAPDH could hardly be detected. Furthermore, small RNA sequencing for mitochondria RNAs from failing hearts was performed. It was found that 69 microRNAs were upregulated and 2 were downregulated in early heart failure, while 16 microRNAs were upregulated and 6 were downregulated in late heart failure. 15 microRNA candidates were measured in both mitochondria and total cardiac tissues of heart failure by real-time PCR. MiR-696, miR-532, miR-690, and miR-345-3p were enriched in mitochondria from the failing heart at early stage. Bioinformatics analysis showed that mitochondria enriched microRNAs in HF were associated with energy metabolism and oxidative stress pathway. For the first time, we demonstrated microRNAs were enriched in mitochondria during heart failure, which established a link between microRNA and mitochondrion in heart failure.
Project description:Acute heart failure (AHF) represents a common clinical scenario that requires prompt evaluation and therapy and that is characterized by a high risk of mortality or subsequent rehospitalizations. The pathophysiology leading to AHF decompensation is still not fully understood. Significant activation of inflammatory pathways has been identified in patients with AHF, particularly in its most severe forms, and it has been hypothesized that systemic inflammation has a role in AHF pathogenesis. Several inflammatory mediators and cytokines, such as high sensitivity C-reactive protein, tumor necrosis factor-α, interleukin-6, interleukin-1, soluble suppression of tumorigenicity 2 and galectin-3, have been shown to play a role in the pathogenesis, development and worsening of this condition with an independent prediction of adverse outcomes. This manuscript reviews the prevalence and prognostic value of systemic inflammation in AHF, as well as the potential role of anti-inflammatory therapies, focusing on available evidence from clinical trials and ongoing studies.
Project description:Mitochondria are considered the main organelles in the cell. They play an important role in both normal and abnormal heart function. There is a supramolecular organization between the complexes of the respiratory chain (supercomplexes (SCs)), which are involved in mitochondrial respiration. Prohibitins (PHBs) participate in the regulation of oxidative phosphorylation (OXPHOS) activity and interact with some subunits of the OXPHOS complexes. In this study, we identified a protein whose level was decreased in the mitochondria of the heart in rats with heart failure. This protein was PHB. Isoproterenol (ISO) has been used as a compound to induce heart failure in rats. We observed that astaxanthin (AX) increased the content of PHB in rat heart mitochondria isolated from ISO-injected rats. Since it is known that PHB forms complexes with some mitochondrial proteins and proteins that are part of the complexes of the respiratory chain, the change in the levels of these proteins was investigated under our experimental conditions. We hypothesized that PHB may be a target for the protective action of AX.
Project description:The burden of heart failure (HF) in terms of health care expenditures, hospitalizations, and mortality is substantial and growing. The failing heart has been described as "energy-deprived" and mitochondrial dysfunction is a driving force associated with this energy supply-demand imbalance. Existing HF therapies provide symptomatic and longevity benefit by reducing cardiac workload through heart rate reduction and reduction of preload and afterload but do not address the underlying causes of abnormal myocardial energetic nor directly target mitochondrial abnormalities. Numerous studies in animal models of HF as well as myocardial tissue from explanted failed human hearts have shown that the failing heart manifests abnormalities of mitochondrial structure, dynamics, and function that lead to a marked increase in the formation of damaging reactive oxygen species and a marked reduction in on demand adenosine triphosphate synthesis. Correcting mitochondrial dysfunction therefore offers considerable potential as a new therapeutic approach to improve overall cardiac function, quality of life, and survival for patients with HF.
Project description:Liver failure induced by systemic inflammatory response (SIRS) is often associated with mitochondrial dysfunction but the mechanism linking SIRS and mitochondria-mediated liver failure is still a matter of discussion. Current hypotheses suggest that causative events could be a drop in ATP synthesis, opening of mitochondrial permeability transition pore, specific changes in mitochondrial morphology, impaired Ca2+ uptake, generation of mitochondrial reactive oxygen species (mtROS), turnover of mitochondria and imbalance in electron supply to the respiratory chain. The aim of this review is to critically analyze existing hypotheses, in order to highlight the most promising research lines helping to prevent liver failure induced by SIRS. Evaluation of the literature shows that there is no consistent support that impaired Ca++ metabolism, electron transport chain function and ultrastructure of mitochondria substantially contribute to liver failure. Moreover, our analysis suggests that the drop in ATP levels has protective rather than a deleterious character. Recent data suggest that the most critical mitochondrial event occurring upon SIRS is the release of mtROS in cytoplasm, which can activate two specific intracellular signaling cascades. The first is the mtROS-mediated activation of NADPH-oxidase in liver macrophages and endothelial cells; the second is the acceleration of the expression of inflammatory genes in hepatocytes. The signaling action of mtROS is strictly controlled in mitochondria at three points, (i) at the site of ROS generation at complex I, (ii) the site of mtROS release in cytoplasm via permeability transition pore, and (iii) interaction with specific kinases in cytoplasm. The systems controlling mtROS-signaling include pro- and anti-inflammatory mediators, nitric oxide, Ca2+ and NADPH-oxidase. Analysis of the literature suggests that further research should be focused on the impact of mtROS on organ failure induced by inflammation and simultaneously providing a new theoretical basis for a targeted therapy of overwhelmed inflammatory response.
Project description:AimsMitochondrial dysfunction is a major factor in heart failure (HF). A pronounced variability of mitochondrial electron transport chain (ETC) defects is reported to occur in severe acquired cardiomyopathies without a consistent trend for depressed activity or expression. The aim of this study was to define the defect in the integrative function of cardiac mitochondria in coronary microembolization-induced HF.Methods and resultsStudies were performed in the canine coronary microembolization-induced HF model of moderate severity. Oxidative phosphorylation was assessed as the integrative function of mitochondria, using a comprehensive variety of substrates in order to investigate mitochondrial membrane transport, dehydrogenase activity and electron-transport coupled to ATP synthesis. The supramolecular organization of the mitochondrial ETC also was investigated by native gel electrophoresis. We found a dramatic decrease in ADP-stimulated respiration that was not relieved by an uncoupler. Moreover, the ADP/O ratio was normal, indicating no defect in the phosphorylation apparatus. The data point to a defect in oxidative phosphorylation within the ETC. However, the individual activities of ETC complexes were normal. The amount of the supercomplex consisting of complex I/complex III dimer/complex IV, the major form of respirasome considered essential for oxidative phosphorylation, was decreased.ConclusionsWe propose that the mitochondrial defect lies in the supermolecular assembly rather than in the individual components of the ETC.
Project description:With the intention to summarize the currently available evidence on the pathophysiological relevance of inflammation in heart failure, this review addresses the question whether inflammation is a cause or consequence of heart failure, or both.This review discusses the diversity (sterile, para-inflammation, chronic inflammation) and sources of inflammation and gives an overview of how inflammation (local versus systemic) can trigger heart failure. On the other hand, the review is outlined how heart failure-associated wall stress and signals released by stressed, malfunctioning, or dead cells (DAMPs: e.g., mitochondrial DNA, ATP, S100A8, matricellular proteins) induce cardiac sterile inflammation and how heart failure provokes inflammation in various peripheral tissues in a direct (inflammatory) and indirect (hemodynamic) manner. The crosstalk between the heart and peripheral organs (bone marrow, spleen, gut, adipose tissue) is outlined and the importance of neurohormonal mechanisms including the renin angiotensin aldosteron system and the ß-adrenergic nervous system in inflammation and heart failure is discussed. Inflammation and heart failure are strongly interconnected and mutually reinforce each other. This indicates the difficulty to counteract inflammation and heart failure once this chronic vicious circle has started and points out the need to control the inflammatory process at an early stage avoiding chronic inflammation and heart failure. The diversity of inflammation further addresses the need for a tailored characterization of inflammation enabling differentiation of inflammation and subsequent target-specific strategies. It is expected that the characterization of the systemic and/or cardiac immune profile will be part of precision medicine in the future of cardiology.