Mechanism Of Mitochondrial Damage Research Articles

The emerging role of mtDNA release in sepsis: Current evidence and potential therapeutic targets.

Sepsis is a systemic inflammatory reaction caused by infection, and severe sepsis can develop into septic shock, eventually leading to multiorgan dysfunction and even death. In recent years, studies have shown that mitochondrial damage is closely related to the occurrence and development of sepsis. Recent years have seen a surge in concern over mitochondrial DNA (mtDNA), as anomalies in this material can lead to cellular dysfunction, disruption of aerobic respiration, and even death of the cell. In this review, we discuss the latest findings on the mechanisms of mitochondrial damage and the molecular mechanisms controlling mitochondrial mtDNA release. We also explored the connection between mtDNA misplacement and inflammatory activation. Additionally, we propose potential therapeutic targets of mtDNA for sepsis treatment.

Mechanism of Mitochondrial Damage in Cardiac Dysfunction Induced by Sepsis

Sepsis is a syndrome with a high fatality rate, which is the dysfunction of multiple organs in the whole body caused by the host’s inflammation response caused by infection. The cardiac insufficiency caused by sepsis is called Septic-Induced Myocardial Dysfunction (SIMD), which is mainly characterized by bilateral systolic and diastolic dysfunction of the heart, which is one of the most serious complications of sepsis. Normal mitochondrial structure and function are essential for maintaining mitochondrial homeostasis. Mitochondrial homeostasis plays a central role in the pathophysiology of SIMD, and its structural changes, oxidative stress, inflammation, endoplasmic reticulum stress and autophagy are directly or indirectly related to the occurrence and development of SIMD, which has a promising future as a targeted therapy for SIMD. Therefore, this paper focuses on the molecular mechanism and signaling pathway of mitochondrial homeostasis in the pathogenesis of SIMD, and provides implications for the search for therapeutic targets and biomarkers of SIMD. In addition, many traditional Chinese medicine components play a protective role in maintaining mitochondrial homeostasis in sepsis, and have the potential to be developed as novel therapeutics for SIMD.

Mitochondrial oxidative stress regulates LonP1-TDP-43 pathway and rises mitochondrial damage in carbon tetrachloride-induced liver fibrosis

Carbon tetrachloride (CCl4)-mediated liver damage has been well recognized, but the sources and mechanisms of mitochondrial damage during this progress still remain poorly understood. Accumulating evidence has revealed that LonP1-TDP-43 pathway affect proper mitochondrial integrity and function in neurodegenerative diseases. The current study aims to investigate whether mitochondrial oxidative stress regulate LonP1-TDP-43 pathway and the possible roles of this pathway in CCl4-driven liver fibrosis. We found that TDP-43 interacted with LonP1 in chronic CCl4 exposure-induced hepatic fibrogenesis. Moreover, CCl4 led to deficiency of LonP1 and excessive accumulation of TDP-43 on mitochondria. Particularly, the gene correlation analysis for liver fibrosis patients RNA sequencing (RNA-seq) results (GSE159676) showed an obvious negative correlation between LonP1 and TDP-43. By contrast, MitoQ enhanced the occurrence of mitochondrial unfolded protein response (mtUPR), especially the activation of LonP1 after CCl4 treatment. Importantly, mitochondrial antioxidant also promoted the degradation of TDP-43 and alleviated mitochondrial damage. In addition, our results showed that CCl4 induced the release of mitochondrial DNA (mtDNA) and effectively elevated cGAS-STING-mediated immune response, which can be inhibited by MitoQ. Finally, MitoQ prevented CCl4-induced liver fibrosis. Together, our study revealed that LonP1-TDP-43 pathway mediated by mitochondrial oxidative stress participated in the progress of CCl4-drived liver fibrosis. Therefore, mitigating or reversing mitochondrial damage through targeting LonP1-TDP-43 pathway may serve as a promising therapeutic strategy for CCl4 exposure-induced liver diseases.

Research progress on hepatotoxicity of acetaminophen

Acetaminophen (APAP) is a widely used antipyretic and analgesic drug that is safe and effective in the therapeutic doses, but overdose may cause hepatotoxicity and even acute liver failure (ALF). Finding reliable biomarkers for APAP toxicity is not only a hot spot of current research, but also a problem that needs to be solved urgently. Clinicians should consider the existence of APAP hepatotoxicity when using APAP treatment, and explain that APAP may have a certain degree of dose dependence. This paper reviews the most promising biomarkers currently being evaluated, and expounds their application in the field of APAP hepatotoxicity, as well as the mechanism of mitochondrial damage and mitochondrial autophagy, thereby contributing to the diagnosis, prognosis, mechanism and research progress of therapeutic targets of APAP hepatotoxicity.

Mitochondrial dysfunction in endothelial cells induced by airborne fine particulate matter (

Exposure to ambient fine particulate matter (<2.5μm; PM2.5 ) increases the risk of the physiopathology of vascular diseases. However, the underlying mechanism, particularly the mitochondrial damage mechanism, of PM2.5 -induced vascular dysfunction is still unclear. In this study, we examined PM2.5 -induced alterations of mitochondrial morphology, and further demonstrated the adverse effects on mitochondrial dynamics and function in vascular endothelial cells. Consequently, cultured EA.hy926 cells were subjected to PM2.5 collected from Beijing. A Cell Counting Assay Kit-8 demonstrated that PM2.5 exposure decreased the proliferation of EA.hy926 cells in a dose-dependent manner. The exposure caused an increment of abnormal mitochondria coupled with the decrease of fusion protein MFN2 and the increase of fission protein FIS1, suggesting that PM2.5 inhibits mitochondrial fusion. Further analyses revealed PM2.5 decreased the mitochondrial membrane potential (ΔΨm) and increased the mitochondrial permeability transport pore opening, eventually resulting in impairments in adenosine triphosphate synthesis. Therefore, it is clearly shown that PM2.5 triggered endothelial toxicity through mitochondria as the target, including the damage of mitochondrial homeostasis.

Mitochondrial DNA Leakage Caused by Streptococcus pneumoniae Hydrogen Peroxide Promotes Type I IFN Expression in Lung Cells.

Streptococcus pneumoniae (S. pn), the bacterial pathogen responsible for invasive pneumococcal diseases, is capable of producing substantial amounts of hydrogen peroxide. However, the impact of S. pn-secreted hydrogen peroxide (H2O2) on the host immune processes is not completely understood. Here, we demonstrated that S. pn-secreted H2O2 caused mitochondrial damage and severe histopathological damage in mouse lung tissue. Additionally, S. pn-secreted H2O2 caused not only oxidative damage to mitochondrial deoxyribonucleic acid (mtDNA), but also a reduction in the mtDNA content in alveolar epithelia cells. This resulted in the release of mtDNA into the cytoplasm, which subsequently induced type I interferons (IFN-I) expression. We also determined that stimulator of interferon genes (STING) signaling was probably involved in S. pn H2O2-inducing IFN-I expression in response to mtDNA damaged by S. pn-secreted H2O2. In conclusion, our study demonstrated that H2O2 produced by S. pn resulted in mtDNA leakage from damaged mitochondria and IFN-I production in alveolar epithelia cells, and STING may be required in this process, and this is a novel mitochondrial damage mechanism by which S. pn potentiates the IFN-I cascade in S. pn infection.

Role of mitochondrial dysfunction in the pathogenesis of septic cardiomyopathy

The incidence and mortality of septic cardiomyopathy were high, which is the common cause of death in the patients with sepsis. The pathogenesis of sepsis induced myocardial injury is still unclear. The mitochondrial dysfunction of myocardial cells plays a very important role in the pathophysiological mechanism. This review attempts to introduce the mitochondrial damage of cardiomyocyte from the regulation of mitochondrial energy metabolism, the mechanism of mitochondrial damage, the role of aquaporin and the adjustment of mitochondrial dynamic, in order to provide help for the early prevention of septic cardiomyopathy.

Mechanism of anti-aging therapy on Parkinson's disease

Many studies have shown that anti-aging treatment has value to prevention and treatment of some diseases. For the treatment of Parkinson' s disease, clinical and experimental researches have proved the potential value of anti-aging treatment, yet the mechanism remains unclear. For this reason, this work used the anti-aging prescriptions of Buyang Huanwu decoction in traditional Chinese medicines example to discover the anti-aging treatment mechanism on Parkinson's disease. The results showed that the mechanism of mitochondrial damage, apoptosis, free radicals and oxidative stress could contribute to the treatment of Parkinson' s disease. Buyang Huanwu decoction is more than as the carrier in this article, the discovered anti-aging treatment mechanism Parkinson's disease is not confined to Buyang Huanwu decoction, could also be used to understand the anti-aging treatment mechanism using other prescription. The main contribution of this paper is to clarify the mechanism of anti-aging treatment of Parkinson's disease, and provide a new strategy for the treatment and prevention of Parkinson's disease.

Mitochondrial damage: An important mechanism of ambient PM2.5 exposure-induced acute heart injury in rats

Epidemiological studies suggested that ambient fine particulate matter (PM2.5) exposure was associated with cardiovascular disease. However, the underlying mechanism, especially the mitochondrial damage mechanism, of PM2.5-induced heart acute injury is still unclear. In this study, the alterations of mitochondrial morphology and mitochondrial fission/fusion gene expression, oxidative stress, calcium homeostasis and inflammation in hearts of rats exposed to PM2.5 with different dosages (0.375, 1.5, 6.0 and 24.0mg/kg body weight) were investigated. The results indicated that the PM2.5 exposure induced pathological changes and ultra-structural damage in hearts such as mitochondrial swell and cristae disorder. Furthermore, PM2.5 exposure significantly increased specific mitochondrial fission/fusion gene (Fis1, Mfn1, Mfn2, Drp1 and OPA1) expression in rat hearts. These changes were accompanied by decreases of activities of superoxide dismutase (SOD), Na+K+-ATPase and Ca2+-ATPase and increases of levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS) and nitric oxide (NO) as well as levels of pro-inflammatory mediators including TNF-α, IL-6 and IL-1β in rat hearts. The results implicate that mitochondrial damage, oxidative stress, cellular homeostasis imbalance and inflammation are potentially important mechanisms for the PM2.5-induced heart injury, and may have relations with cardiovascular disease.

Mechanisms of Mitochondrial Damage in Keratinocytes by Pemphigus Vulgaris Antibodies

The development of nonhormonal treatment of pemphigus vulgaris (PV) has been hampered by a lack of clear understanding of the mechanisms leading to keratinocyte (KC) detachment and death in pemphigus. In this study, we sought to identify changes in the vital mitochondrial functions in KCs treated with the sera from PV patients and healthy donors. PV sera significantly increased proton leakage from KCs, suggesting that PV IgGs increase production of reactive oxygen species. Indeed, measurement of intracellular reactive oxygen species production showed a drastic increase of cell staining in response to treatment by PV sera, which was confirmed by FACS analysis. Exposure of KCs to PV sera also caused dramatic changes in the mitochondrial membrane potential detected with the JC-1 dye. These changes can trigger the mitochondria-mediated intrinsic apoptosis. Although sera from different PV patients elicited unique patterns of mitochondrial damage, the mitochondria-protecting drugs nicotinamide (also called niacinamide), minocycline, and cyclosporine A exhibited a uniform protective effect. Their therapeutic activity was validated in the passive transfer model of PV in neonatal BALB/c mice. The highest efficacy of mitochondrial protection of the combination of these drugs found in mitochondrial assay was consistent with the ability of the same drug combination to abolish acantholysis in mouse skin. These findings provide a theoretical background for clinical reports of the efficacy of mitochondria-protecting drugs in PV patients. Pharmacological protection of mitochondria and/or compensation of an altered mitochondrial function may therefore become a novel approach to development of personalized nonhormonal therapies of patients with this potentially lethal autoimmune blistering disease.

Molecular mechanisms of mitochondrial damage in the development of liver failure

肝功能衰竭是由多种因素引起的,以肝细胞大量凋亡、坏死为特征的临床综合征.其病情危重,发展迅速,病死率高达60％～80％.线粒体是真核细胞中一种非常重要的细胞器,与肝脏的生物合成、代谢和解毒功能密不可分.三羧酸循环、脂肪酸β-氧化、氧化磷酸化及鸟氨酸循环等均在线粒体内进行.此外,线粒体在调节细胞内钙离子浓度、信息传递及细胞死亡等过程中也具有重要作用.线粒体是肝细胞内较敏感的细胞器之一,多种急、慢性肝病均存在线粒体结构和功能的异常.有研究结果显示,线粒体与肝衰竭的发病关系密切,可能的作用途径包括:呼吸链被抑制导致三磷酸腺苷(adenosine-triphosphate,ATP)耗竭、氧化应激、脂肪酸β-氧化的抑制、线粒体通透性转换(mitochondrial permeability transition,MPT)所致肝细胞凋亡或坏死等,但其作用机制尚未完全阐明[1].现就目前的相关研究进展作一综述. 关键词：线粒体;肝功能衰竭;氧化应激;细胞凋亡;线粒体通透性转换孔

Regulation of mitochondrial dynamics in acute kidney injury in cell culture and rodent models

The mechanism of mitochondrial damage, a key contributor to renal tubular cell death during acute kidney injury, remains largely unknown. Here, we have demonstrated a striking morphological change of mitochondria in experimental models of renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. This change contributed to mitochondrial outer membrane permeabilization, release of apoptogenic factors, and consequent apoptosis. Following either ATP depletion or cisplatin treatment of rat renal tubular cells, mitochondrial fragmentation was observed prior to cytochrome c release and apoptosis. This mitochondrial fragmentation was inhibited by Bcl2 but not by caspase inhibitors. Dynamin-related protein 1 (Drp1), a critical mitochondrial fission protein, translocated to mitochondria early during tubular cell injury, and both siRNA knockdown of Drp1 and expression of a dominant-negative Drp1 attenuated mitochondrial fragmentation, cytochrome c release, caspase activation, and apoptosis. Further in vivo analysis revealed that mitochondrial fragmentation also occurred in proximal tubular cells in mice during renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. Notably, both tubular cell apoptosis and acute kidney injury were attenuated by mdivi-1, a newly identified pharmacological inhibitor of Drp1. This study demonstrates a rapid regulation of mitochondrial dynamics during acute kidney injury and identifies mitochondrial fragmentation as what we believe to be a novel mechanism contributing to mitochondrial damage and apoptosis in vivo in mouse models of disease.

Ascorbate and low concentrations of FeSO4 induce Ca2+-dependent pore in rat liver mitochondria.

Oxidative stress is one of the most frequent causes of tissue and cell injury in various pathologies. The molecular mechanism of mitochondrial damage under conditions of oxidative stress induced in vitro with low concentrations of FeSO4 and ascorbate (vitamin C) was studied. FeSO4 (1-4 microM) added to rat liver mitochondria that were incubated in the presence of 2.3 mM ascorbate induced (with a certain delay) a decrease in membrane potential and high-amplitude swelling. It also significantly decreased the ability of mitochondria to accumulate exogenous Ca2+. All the effects of FeSO4 + ascorbate were essentially prevented by cyclosporin A, a specific inhibitor of the mitochondrial Ca2+-dependent pore (also known as the mitochondrial permeability transition). EGTA restored the membrane potential of mitochondria de-energized with FeSO4 + ascorbate. We hypothesize that oxidative stress induced in vitro with FeSO4 and millimolar concentrations of ascorbate damages mitochondria by inducing the cyclosporin A-sensitive Ca2+-dependent pore in the inner mitochondrial membrane.

A mechanism of mitochondrial damage induced by tert-butyl hydroperoxide and microsomes in vitro

A mechanism of mitochondrial damage induced by tert-butyl hydroperoxide and microsomes in vitro

The effect of coenzyme Q 10 on reperfusion injury in canine myocardium

The mechanism of mitochondrial damage during reperfusion injury of ischemic myocardium was studied using mongrel dogs in vivo and isolated mitochondria in vitro. Seventy-seven adult dogs were divided into three groups: the control group (n = 38), the Coenzyme Q10 (CoQ10)-5 mg group (n = 24), and the CoQ10-15 mg group (n = 15). In the control group, the left anterior descending coronary artery (LAD) of the dog was occluded for 15 min followed by 5 min of reperfusion after 40 min of premedication with physiological saline. In both CoQ10 groups, 5 mg/kg or 15 mg/kg of CoQ10 was infused intravenously for 20 min and then physiological saline was administered for 20 min before 15 min occlusion of the LAD. Subsequently, reperfusion was allowed for 5 min. Each group was further divided into two subgroups depending on the presence (arrhythmia group) or the absence (non-arrhythmia group) of ventricular arrhythmias. Immediately after 15 min occlusion, myocardial samples were taken from the normal and reperfused areas to measure CoQ10 content of myocardium. Heart mitochondria were prepared after 5 min of reperfusion from both areas. Arrhythmias appeared in 12 of 38 dogs in the control group (32%), two of 24 dogs in the CoQ10-5 mg group (8%) and none of 15 dogs in the CoQ10-15 mg group (0%). Premedication with CoQ10 increased tissue CoQ10 content in a dose-dependent manner. In the CoQ10-5 mg group, the increase in CoQ10 content of dogs with reperfusion arrhythmias was relatively less than that of dogs without reperfusion arrhythmias. In each group, mitochondrial function was decreased in the arrhythmia group compared to that of the non-arrhythmia group. The increase in free fatty acid (FFA) content and the decrease in phospholipid content were also observed in mitochondria from the reperfused area of each arrhythmia group. The increase in FFA and mitochondrial dysfunction were induced by the incubation of mitochondria in vitro with phospholipase (PLase) A2 or PLase C, and protected by the addition of CoQ10. These results suggest that PLase plays an important role in the development of mitochondrial damage associated with reperfusion.

Mechanism of mitochondrial damage after coronary reperfusion.

We investigated the mechanism of the reperfusion-accelerated mitochondrial dysfunction. To clarify this mechanism, we performed the following experiments using 40 mongrel dogs. Experiment I: Prostaglandin (PG) E and F2 alpha levels in the great cardiac vein (GCV) were examined before, during occlusion and after reperfusion of the left anterior descending coronary artery (LAD). Experiment II: Heart mitochondria were prepared from the normal area and the occluded or the reperfused area after 15 min of the LAD occlusion, or after 5 min of reperfusion following the occlusion with or without premedication of indomethacin. The PGE level in the GCV did not change significantly during occlusion, but increased significantly soon after reperfusion. Mitochondrial dysfunction was caused by occlusion and further accelerated by reperfusion. The PG E level in mitochondria isolated from the reperfused area increased significantly. Indomethacin significantly prevented both the increase in PG E and the acceleration of mitochondrial dysfunction by reperfusion. These results suggest that the increase in PG E level is closely related to the reperfusion-accelerated mitochondrial dysfunction, and that premedication with indomethacin significantly prevented the extension of mitochondrial dysfunction induced by coronary reperfusion.

Mitochondrial oxidative phosphorylation in low-flow hypoxia: Role of free fatty acids

The mechanism of mitochondrial damage was investigated in hypoxic hearts, perfused at low pressure without exogenous substrate, as a model of myocardial ischaemia. Mitochondrial and tissue free fatty acid (FFA) contents were determined in control hearts (perfused aerobically at a higher pressure, without exogenous substrate), and in the hypoxic hearts; the functional capacities of mitochondria isolated from the two types of tissue were also compared. Mitochondrial FFA contents were found to be elevated, relative to the controls, after 20 min of low-flow hypoxic perfusion. However, mitochondrial FFA contents were not different in control and hypoxic hearts after 70 min of perfusion. Low-flow hypoxic perfusion for 70 min caused a significant elevation of tissue C16:0, C18:0 and C18:1 FFA fractions, while total FFA and triglyceride contents were also increased. Accumulation of FFA in whole tissue was accompanied by a depression in mitochondrial function. Thus, after 20 min, both tissue FFA contents and ADP O and RCI values of mitochondria isolated from control and hypoxic hearts were not different, whereas after 70 min, tissue FFA levels were significantly elevated in hypoxic hearts, with an equally significant depression in the function of isolated mitochondria.

The hypoxic, low-flow perfused rat heart: characterization as a model of global ischaemia

In the study of the mechanism of mitochondrial damage in myocardial ischaemia, production of a small animal model of global ischaemia proved to be necessary. Thus, the effects of coronary flow rate, oxygen availability and substrate availability were studied on the functional capacity of mitochondria isolated from perfused rat hearts. The hypoxic, low-flow perfused heart eventually chosen was evaluated as a model of myocardial ischaemia by measuring tissue contents of high energy phosphate compounds and glycolytic intermediates and by assessing the effects of exogenous substrates on the above parameters.