scholarly journals Protective Effects of Euthyroidism Restoration on Mitochondria Function and Quality Control in Cardiac Pathophysiology

2019 ◽  
Vol 20 (14) ◽  
pp. 3377 ◽  
Author(s):  
Francesca Forini ◽  
Giuseppina Nicolini ◽  
Claudia Kusmic ◽  
Giorgio Iervasi

Mitochondrial dysfunctions are major contributors to heart disease onset and progression. Under ischemic injuries or cardiac overload, mitochondrial-derived oxidative stress, Ca2+ dis-homeostasis, and inflammation initiate cross-talking vicious cycles leading to defects of mitochondrial DNA, lipids, and proteins, concurrently resulting in fatal energy crisis and cell loss. Blunting such noxious stimuli and preserving mitochondrial homeostasis are essential to cell survival. In this context, mitochondrial quality control (MQC) represents an expanding research topic and therapeutic target in the field of cardiac physiology. MQC is a multi-tier surveillance system operating at the protein, organelle, and cell level to repair or eliminate damaged mitochondrial components and replace them by biogenesis. Novel evidence highlights the critical role of thyroid hormones (TH) in regulating multiple aspects of MQC, resulting in increased organelle turnover, improved mitochondrial bioenergetics, and the retention of cell function. In the present review, these emerging protective effects are discussed in the context of cardiac ischemia-reperfusion (IR) and heart failure, focusing on MQC as a strategy to blunt the propagation of connected dangerous signaling cascades and limit adverse remodeling. A better understanding of such TH-dependent signaling could provide insights into the development of mitochondria-targeted treatments in patients with cardiac disease.

2017 ◽  
Vol 43 (5) ◽  
pp. 1813-1828 ◽  
Author(s):  
Qiu Zeng ◽  
Qining Fu ◽  
Xuehu Wang ◽  
Yu Zhao ◽  
Hong Liu ◽  
...  

Background/Aims: Skeletal muscle ischemia/reperfusion (I/R) injury is a common and severe disease. Sonic hedgehog (Shh) plays a critical role in post-natal skeletal muscle regeneration. In the present study, the role of Shh in skeletal muscle I/R injury and the mechanisms involved were investigated. Methods: The expression of Shh, AKT/mTOR/p70S6K and apoptosis pathway components were evaluated following tourniquet-induced skeletal muscle I/R injury. Then, mice were subjected to systemic administration of cyclopamine or one-shot treatment of a plasmid encoding the human Shh gene (phShh) to examine the effects of Shh on I/R injury. Moreover, mice were subjected to systemic administration of NVP-BEZ235 to investigate the role of the AKT/mTOR/p70S6K pathway in Shh-triggered skeletal muscle protection. Results: We found that the levels of Shh, AKT/mTOR/p70S6K pathway components and Cleaved Caspase 3 and the Bax/Bcl2 ratio initially increased and then decreased at different time points post-I/R injury. Moreover, Shh protected skeletal muscle against I/R injury by alleviating muscle destruction, reducing interstitial fibrosis and inhibiting apoptosis, and these protective effects were abrogated when the AKT/mTOR/p70S6K pathway was inhibited. Conclusion: Collectively, these data suggest that Shh signaling exerts a protective role through the AKT/mTOR/p70S6K signaling pathway during skeletal muscle I/R injury. Thus, Shh signaling may be a therapeutic target for protecting skeletal muscle from I/R injury.


2018 ◽  
Vol 127 (05) ◽  
pp. 320-325 ◽  
Author(s):  
Fatemeh Ramezani-Aliakbari ◽  
Mohammad Badavi ◽  
Mahin Dianat ◽  
Seyed Mard ◽  
Akram Ahangarpour

AbstractTrimetazidine (TMZ), as an anti-ischemic drug, plays a critical role in protecting against cardiovascular complications induced by diabetes. This study was therefore aimed to evaluate the protective effects of TMZ on reperfusion-induced arrhythmias in the diabetic rats. Male Sprague-Dawley rats (250±20 g) were randomly assigned to four (n=8): control rats (C), alloxan induced diabetic rats (D), diabetic rats treated with TMZ (10 mg/kg, D+T10), diabetic rats treated with TMZ (30 mg/kg, D+T30). TMZ was treated orally once daily for 8 weeks. Diabetes was induced by a single intraperitoneal injection of alloxan (120 mg/kg). Ischemia-reperfusion (I/R) was carried out via 30 min of ischemia and following120-min reperfusion. The magnitude and score of arrhythmia, the left ventricular function, infarct size, lactate dehydrogenase (LDH), myocardial creatine kinase (CK-MB) and troponin (cTnI) were measured. The findings were evaluated by two-way repeated measures and one-way ANOVA followed by LSD post hoc test and Fisher's exact test for incidence percentage. The duration, incidence and score of arrhythmia (p<0.001), infarct size (p<0.01) were significantly increased, the cardiac contractility (±dp/dt), LDH, CK-MB (p<0.001) and cTnI (p<0.05) were significantly decreased in the diabetic rats in comparison with the control group. However, treatment with TMZ in the diabetic rats was significantly improved the duration (p<0.001), incidence and score of arrhythmia,±dp/dt LDH, CK-MB, cTnI (p<0.05) and infarct size (p<0.01) in comparison with the untreated diabetic group. The present study indicates anti-arrhythmic effect of TMZ in reducing arrhythmias induced by reperfusion in the diabetic rats.


Author(s):  
Shanjun Zhao ◽  
Lei Yu

BACKGROUND: Ischemia reperfusion usually results in certain degree of damage to the myocardium, which is called myocardial ischemia/reperfusion (I/R) injury. OBJECTIVE: Previous studies have found that Sirt1 plays a critical role in I/R injury by protecting cardiac function. SRT1460 is the activator for Sirt1 that participates in the regulation of various diseases. However, whether SRT1460 has any effects on myocardial I/R injury needs further study. METHODS: The I/R rat model and H/R H9C2 model were established to simulate myocardial I/R injury. The infarct area of the rat heart was examined through TTC staining. The EF and FS of rats were detected through echocardiography. The levels of CK-MB, LDH, MDA, SOD and CK in cardiac tissues, serum or H9C2 cells were measured using commercial kits. Cell viability was assessed through MTT assay. Apoptosis was determined through flow cytometry analysis. Sirt1 expression was measured through western blot. RESULTS: Our work found that SRT1460 reduced the infarct area of the heart induced by myocardial I/R injury. In addition, SRT1460 was confirmed to ameliorate cardiac dysfunction induced by myocardial I/R injury. Further exploration discovered that SRT1460 weakened oxidative stress induced by myocardial I/R injury. Findings from in vitro assays demonstrated that SRT1460 relieved injury of H/R-treated H9C2 cells. Finally, rescue assays proved that Sirt1 knockdown reversed the protective effects of SRT1460 on the injury of H/R-treated H9C2 cells. CONCLUSION: Sirt1 activated by SRT1460 protected against myocardial I/R injury. This discovery may offer new sights on the treatment of myocardial I/R injury.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jia Huang ◽  
Ruibing Li ◽  
Chengbin Wang

A healthy mitochondrial network produces a large amount of ATP and biosynthetic intermediates to provide sufficient energy for myocardium and maintain normal cell metabolism. Mitochondria form a dynamic and interconnected network involved in various cellular metabolic signaling pathways. As mitochondria are damaged, controlling mitochondrial quantity and quality is activated by changing their morphology and tube network structure, mitophagy, and biogenesis to replenish a healthy mitochondrial network to preserve cell function. There is no doubt that mitochondrial dysfunction has become a key factor in many diseases. Ischemia/reperfusion (IR) injury is a pathological manifestation of various heart diseases. Cardiac ischemia causes temporary tissue and organelle damage. Although reperfusion is essential to compensate for nutrient deficiency, blood flow restoration inconsequently further kills the previously ischemic cardiomyocytes. To date, dysfunctional mitochondria and disturbed mitochondrial quality control have been identified as critical IR injury mechanisms. Many researchers have detected abnormal mitochondrial morphology and mitophagy, as well as aberrant levels and activity of mitochondrial biogenesis factors in the IR injury model. Although mitochondrial damage is well-known in myocardial IR injury, the causal relationship between abnormal mitochondrial quality control and IR injury has not been established. This review briefly describes the molecular mechanisms of mitochondrial quality control, summarizes our current understanding of the complex role of mitochondrial quality control in IR injury, and finally speculates on the possibility of targeted control of mitochondria and the methods available to mitigate IR injury.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xu Luo ◽  
Shumin Cai ◽  
Yunfeng Li ◽  
Guicheng Li ◽  
Yuanyuan Cao ◽  
...  

Mitochondria-dependent apoptotic signaling has a critical role in the pathogenesis of vascular hyperpermeability (VH). Dynamin-related protein-1- (Drp-1-) mediated mitochondrial fission plays an important role in mitochondrial homeostasis. In the present study, we studied the involvement of Drp-1 in resistance to VH induced by lipopolysaccharide (LPS). To establish the model of LPS-induced VH, LPS at 15 mg/kg was injected into rats in vivo and rat pulmonary microvascular endothelial cells were exposed to 500 ng/ml LPS in vitro. We found that depletion of Drp-1 remarkedly exacerbated the mitochondria-dependent apoptosis induced by LPS, as evidenced by reduced apoptosis, mitochondrial membrane potential (MMP) depolarization, and activation of caspase-3 and caspase-9. Increased FITC-dextran flux indicated endothelial barrier disruption. In addition, overexpression of Drp-1 prevented LPS-induced endothelial hyperpermeability and upregulated mitophagy, as evidenced by the loss of mitochondrial mass and increased PINK1 expression and mitochondrial Parkin. However, the mitophagy inhibitor, 3-Methyladenine, blocked these protective effects of Drp-1. Furthermore, inhibition of Drp-1 using mitochondrial division inhibitor 1 markedly inhibited LPS-induced mitophagy and aggravated LPS-induced VH, as shown by increased FITC-dextran extravasation. These findings implied that Drp-1 strengthens resistance to mitochondria-dependent apoptosis by regulating mitophagy, suggesting Drp-1 as a possible therapeutic target in LPS-induced VH.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jun Shao ◽  
Chen Miao ◽  
Zhi Geng ◽  
Maohong Gu ◽  
Yanhu Wu ◽  
...  

Autophagy is involved in the development of numerous illnesses, including ischemia/reperfusion (I/R). Endothelial nitric oxide synthase (eNOS) participates in the protective effects of ischemic postconditioning (IPostC). However, it remains unclear whether eNOS-mediated autophagy serves as a critical role in IPostC in the hearts of mice, in protecting against I/R injury. In the present study, the hearts of mice with left anterior descending coronary artery ligation were studied as I/R models. H9c2 cells underwent exposure to hypoxia/reoxygenation (H/R) and were examined as in vitro model. IPostC reduced mice myocardial infarct size and improved the structure of the heart. IPostC increased the formation of autophagosomes and increased the phosphorylation of eNOS and adenosine monophosphate-activated protein kinase (AMPK). Autophagy and eNOS inhibition suppressed the cardioprotective effects of IPostC. AMPK or eNOS inhibition abolished the improvement effect of IPostC on autophagy. AMPK inhibition decreased eNOS phosphorylation in the heart. Additionally, H9c2 cells suffering hypoxia were used as in vitro model. Autophagy or eNOS inhibition abolished the protective effects of hypoxic postconditioning (HPostC) against H/R injury. AMPK and eNOS inhibition/knockout decreased autophagic activity in the HPostC group. These results indicated that IPostC protects the heart against I/R injury, partially via promoting AMPK/eNOS-mediated autophagy.


2020 ◽  
Author(s):  
Victoria L. Hewitt ◽  
Leonor Miller-Fleming ◽  
Simonetta Andreazza ◽  
Francesca Mattedi ◽  
Julien Prudent ◽  
...  

AbstractThe complex cellular architecture of neurons combined with their longevity makes maintaining a healthy mitochondrial network particularly important and challenging. One of the many roles of mitochondrial-ER contact sites (MERCs) is to mediate mitochondrial quality control through regulating mitochondrial turn over. Pdzd8 is a newly discovered MERC protein, the organismal functions of which have not yet been explored. Here we identify and provide the first functional characterization of the Drosophila melanogaster ortholog of Pdzd8. We find that reducing pdzd8-mediated MERCs in neurons slows age-associated decline in locomotor activity and increases lifespan in Drosophila. The protective effects of pdzd8 knockdown in neurons correlate with an increase in mitophagy, suggesting that increased mitochondrial turnover may support healthy aging of neurons. In contrast, increasing MERCs by expressing a constitutive, synthetic ER-mitochondria tether disrupts mitochondrial transport and synapse formation, accelerates age-related decline in locomotion and reduces lifespan. We also show that depletion of pdzd8 rescues the locomotor defects characterizing an Alzheimer’s disease (AD) fly model over-expressing Amyloidβ1–42 (Aβ42) and prolongs the survival of flies fed with mitochondrial toxins. Together, our results provide the first in vivo evidence that MERCs mediated by the tethering protein pdzd8 play a critical role in the regulation of mitochondrial quality control and neuronal homeostasis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Hai-Jian Sun ◽  
Zhi-Yuan Wu ◽  
Xiao-Wei Nie ◽  
Xin-Yu Wang ◽  
Jin-Song Bian

Cardiovascular diseases are the most common complications of diabetes, and diabetic cardiomyopathy is a major cause of people death in diabetes. Molecular, transcriptional, animal, and clinical studies have discovered numerous therapeutic targets or drugs for diabetic cardiomyopathy. Within this, hydrogen sulfide (H2S), an endogenous gasotransmitter alongside with nitric oxide (NO) and carbon monoxide (CO), is found to play a critical role in diabetic cardiomyopathy. Recently, the protective roles of H2S in diabetic cardiomyopathy have attracted enormous attention. In addition, H2S donors confer favorable effects in myocardial infarction, ischaemia-reperfusion injury, and heart failure under diabetic conditions. Further studies have disclosed that multiplex molecular mechanisms are responsible for the protective effects of H2S against diabetes-elicited cardiac injury, such as anti-oxidative, anti-apoptotic, anti-inflammatory, and anti-necrotic properties. In this review, we will summarize the current findings on H2S biology and pharmacology, especially focusing on the novel mechanisms of H2S-based protection against diabetic cardiomyopathy. Also, the potential roles of H2S in diabetes-aggravated ischaemia-reperfusion injury are discussed.


2019 ◽  
Vol 316 (6) ◽  
pp. H1426-H1438 ◽  
Author(s):  
Nelson Escobales ◽  
Rebeca E. Nuñez ◽  
Sabzali Javadov

A growing body of data provides strong evidence that intracellular angiotensin II (ANG II) plays an important role in mammalian cell function and is involved in the pathogenesis of human diseases such as hypertension, diabetes, inflammation, fibrosis, arrhythmias, and kidney disease, among others. Recent studies also suggest that intracellular ANG II exerts protective effects in cells during high extracellular levels of the hormone or during chronic stimulation of the local tissue renin-angiotensin system (RAS). Notably, the intracellular RAS (iRAS) described in neurons, fibroblasts, renal cells, and cardiomyocytes provided new insights into regulatory mechanisms mediated by intracellular ANG II type 1 (AT1Rs) and 2 (AT2Rs) receptors, particularly, in mitochondria and nucleus. For instance, ANG II through nuclear AT1Rs promotes protective mechanisms by stimulating the AT2R signaling cascade, which involves mitochondrial AT2Rs and Mas receptors. The stimulation of nuclear ANG II receptors enhances mitochondrial biogenesis through peroxisome proliferator-activated receptor-γ coactivator-1α and increases sirtuins activity, thus protecting the cell against oxidative stress. Recent studies in ANG II-induced preconditioning suggest that plasma membrane AT2R stimulation exerts protective effects against cardiac ischemia-reperfusion by modulating mitochondrial AT1R and AT2R signaling. These studies indicate that iRAS promotes the protection of cells through nuclear AT1R signaling, which, in turn, promotes AT2R-dependent processes in mitochondria. Thus, despite abundant data on the deleterious effects of intracellular ANG II, a growing body of studies also supports a protective role for iRAS that could be of relevance to developing new therapeutic strategies. This review summarizes and discusses previous studies on the role of iRAS, particularly emphasizing the protective and counterbalancing actions of iRAS, mitochondrial ANG II receptors, and their implications for organ protection.


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