scholarly journals Mitochondrial Ion Channels of the Inner Membrane and Their Regulation in Cell Death Signaling

2021 ◽  
Vol 8 ◽  
Author(s):  
Andrea Urbani ◽  
Elena Prosdocimi ◽  
Andrea Carrer ◽  
Vanessa Checchetto ◽  
Ildikò Szabò
Keyword(s):  
Cell Death ◽  
Ion Channels ◽  
Cell Fate ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Second Messengers ◽  
Fine Tuning ◽  
Respiratory Chain Complexes ◽  
Inner Membrane ◽  
Atp Production

Mitochondria are bioenergetic organelles with a plethora of fundamental functions ranging from metabolism and ATP production to modulation of signaling events leading to cell survival or cell death. Ion channels located in the outer and inner mitochondrial membranes critically control mitochondrial function and, as a consequence, also cell fate. Opening or closure of mitochondrial ion channels allow the fine-tuning of mitochondrial membrane potential, ROS production, and function of the respiratory chain complexes. In this review, we critically discuss the intracellular regulatory factors that affect channel activity in the inner membrane of mitochondria and, indirectly, contribute to cell death. These factors include various ligands, kinases, second messengers, and lipids. Comprehension of mitochondrial ion channels regulation in cell death pathways might reveal new therapeutic targets in mitochondria-linked pathologies like cancer, ischemia, reperfusion injury, and neurological disorders.

scholarly journals Protein kinase C-ε activation induces mitochondrial dysfunction and fragmentation in renal proximal tubules

2011 ◽  
Vol 301 (1) ◽  
pp. F197-F208 ◽  
Author(s):  
Grazyna Nowak ◽  
Diana Bakajsova ◽  
Allen M. Samarel
Keyword(s):  
Cell Death ◽  
Mitochondrial Dysfunction ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Primary Cultures ◽  
Protective Effects ◽  
Mitochondrial Fragmentation ◽  
Atp Production ◽  
Mitochondrial Functions ◽  
Oxidant Production

PKC-ε activation mediates protection from ischemia-reperfusion injury in the myocardium. Mitochondria are a subcellular target of these protective mechanisms of PKC-ε. Previously, we have shown that PKC-ε activation is involved in mitochondrial dysfunction in oxidant-injured renal proximal tubular cells (RPTC; Nowak G, Bakajsova D, Clifton GL Am J Physiol Renal Physiol 286: F307–F316, 2004). The goal of this study was to examine the role of PKC-ε activation in mitochondrial dysfunction and to identify mitochondrial targets of PKC-ε in RPTC. The constitutively active and inactive mutants of PKC-ε were overexpressed in primary cultures of RPTC using the adenoviral technique. Increases in active PKC-ε levels were accompanied by PKC-ε translocation to mitochondria. Sustained PKC-ε activation resulted in decreases in state 3 respiration, electron transport rate, ATP production, ATP content, and activities of complexes I and IV and F0F1-ATPase. Furthermore, PKC-ε activation increased mitochondrial membrane potential and oxidant production and induced mitochondrial fragmentation and RPTC death. Accumulation of the dynamin-related protein in mitochondria preceded mitochondrial fragmentation. Antioxidants blocked PKC-ε-induced increases in the oxidant production but did not prevent mitochondrial fragmentation and cell death. The inactive PKC-ε mutant had no effect on mitochondrial functions, morphology, oxidant production, and RPTC viability. We conclude that active PKC-ε targets complexes I and IV and F0F1-ATPase in RPTC. PKC-ε activation mediates mitochondrial dysfunction, hyperpolarization, and fragmentation. It also induces oxidant generation and cell death, but oxidative stress is not the mechanism of RPTC death. These results show that in contrast to protective effects of PKC-ε activation in cardiomyocytes, sustained PKC-ε activation is detrimental to mitochondrial function and viability in RPTC.

scholarly journals TRAP1 Provides Protection Against Myocardial Ischemia-Reperfusion Injury by Ameliorating Mitochondrial Dysfunction

2015 ◽  
Vol 36 (5) ◽  
pp. 2072-2082 ◽  
Author(s):  
Peng Zhang ◽  
Yong Lu ◽  
Dong Yu ◽  
Dadong Zhang ◽  
Wei Hu
Keyword(s):  
Cell Death ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Generation ◽  
Complex Activity ◽  
Atp Production

Background: Tumor necrosis factor receptor-associated protein 1 (TRAP1), an essential mitochondrial chaperone is induced in rat hearts following ischemia/reperfusion (I/R), but its role in myocardial I/R injury is unclear. The present study examined the function of TRAP1 in cardiomyocyte hypoxia/reoxygenation injury in vitro and myocardial I/R injury in vivo. Methods: HL-1 cardiomyocytes transfected with TRAP1 or vector were subjected to simulated I/R (SI/R) in vitro. Cell death and mitochondrial function were assessed. Wild type (WT) and TRAP1 knockout (TRAP1 KO) mice were subjected to cardiac I/R in vivo. The infarct size and myocardial apoptosis were determined. WT and TRAP1 KO cardiomyocytes were subjected to SI/R in vitro. Mitochondrial function was assessed. Results: TRAP1 overexpression protects HL-1 cardiomyocytes from SI/R-induced cell death in vitro. The reduced cell death was associated with decreased ROS generation, better-preserved mitochondrial ETC complex activity, membrane potential, and ATP production, as well as delayed mPTP opening. Loss of TRAP1 aggravates SI/R-induced mitochondrial damage in cardiomyocytes in vitro and myocardial I/R injury and apoptosis in vivo. Conclusion: The results of the present study show that TRAP1 provides cardioprotection against myocardial I/R by ameliorating mitochondrial dysfunction.

Necrostatin-1 Analog DIMO Exerts Cardioprotective Effect against Ischemia Reperfusion Injury by Suppressing Necroptosis via Autophagic Pathway in Rats

Pharmacology ◽  
2021 ◽  
Vol 106 (3-4) ◽  
pp. 189-201
Author(s):  
Shigang Qiao ◽  
Wen-jie Zhao ◽  
Huan-qiu Li ◽  
Gui-zhen Ao ◽  
Jian-zhong An ◽  
...  
Keyword(s):  
Cell Death ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Neonatal Rat ◽  
Ligand Docking ◽  
Autophagic Flux ◽  
Myocardial Infarct Size ◽  
Rat Cardiomyocytes

Aim: It has been reported that necrostatin-1 (Nec-1) is a specific necroptosis inhibitor that could attenuate programmed cell death induced by myocardial ischemia/reperfusion (I/R) injury. This study aimed to observe the effect and mechanism of novel Nec-1 analog (Z)-5-(3,5-dimethoxybenzyl)-2-imine-1-methylimidazolin-4-1 (DIMO) on myocardial I/R injury. Methods: Male SD rats underwent I/R injury with or without different doses of DIMO (1, 2, or 4 mg/kg) treatment. Isolated neonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) treatment with or without DIMO (0.1, 1, 10, or 100 μM). Myocardial infarction was measured by TTC staining. Cardiomyocyte injury was assessed by lactate dehydrogenase assay (LDH) and flow cytometry. Receptor-interacting protein 1 kinase (RIP1K) and autophagic markers were detected by co-immunoprecipitation and Western blotting analysis. Molecular docking of DIMO into the ATP binding site of RIP1K was performed using GLIDE. Results: DIMO at doses of 1 or 2 mg/kg improved myocardial infarct size. However, the DIMO 4 mg/kg dose was ineffective. DIMO at the dose of 0.1 μM decreased LDH leakage and the ratio of PI-positive cells followed by OGD/R treatment. I/R or OGD/R increased RIP1K expression and in its interaction with RIP3K, as well as impaired myocardial autophagic flux evidenced by an increase in LC3-II/I ratio, upregulated P62 and Beclin-1, and activated cathepsin B and L. In contrast, DIMO treatment reduced myocardial cell death and reversed the above mentioned changes in RIP1K and autophagic flux caused by I/R and OGD/R. DIMO binds to RIP1K and inhibits RIP1K expression in a homology modeling and ligand docking. Conclusion: DIMO exerts cardioprotection against I/R- or OGD/R-induced injury, and its mechanisms may be associated with the reduction in RIP1K activation and restoration impaired autophagic flux.

scholarly journals miR-380-5p facilitates NRF2 and attenuates cerebral ischemia/reperfusion injury-induced neuronal cell death by directly targeting BACH1

2021 ◽  
Vol 12 (1) ◽  
pp. 210-217
Author(s):  
Yibiao Wang ◽  
Min Xu
Keyword(s):  
Cell Death ◽  
Cerebral Ischemia ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Luciferase Assay ◽  
Neuroprotective Effects ◽  
Cerebral Ischemia Reperfusion

Abstract Background This study aimed to explore the role of miR-380-5p in cerebral ischemia/reperfusion (CIR) injury-induced neuronal cell death and the potential signaling pathway involved. Methodology Human neuroblastoma cell line SH-SY5Y cells were used in this study. Oxygen and glucose deprivation/reperfusion (OGD/R) model was used to mimic ischemia/reperfusion injury. CCK-8 assay and flow cytometry were used to examine cell survival. Quantitative real time PCR (RT-qPCR) assay and Western blotting were used to measure the change of RNA and protein expression, respectively. TargetScan and Luciferase assay was used to confirm the target of miR-380-5p. Malondialdehyde (MDA) superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) were measured using commercial kits. Results miR-380-5p was downregulated in SH-SY5Y cells after OGD/R. Cell viability was increased by miR-380-5p, while cell apoptosis was reduced by miR-380-5p mimics. MDA was reduced by miR-380-5p mimics, while SOD and GSHPx were increased by miR-380-5p. Results of TargetScan and luciferase assay have showed that BACH1 is the direct target of miR-380-5p. Expression of NRF2 was upregulated after OGD/R, but was not affected by miR-380-5p. mRNA expression of HO-1 and NQO1 and ARE activity were increased by miR-380-5p. Overexpression of BACH1 reversed the antioxidant and neuroprotective effects of miR-380-5p. Conclusion miR-380-5p inhibited cell death induced by CIR injury through target BACH1 which also facilitated the activation of NRF2, indicating the antioxidant and neuroprotective effects of miR-380-5p.

scholarly journals Kaempferol Ameliorates Oxygen-Glucose Deprivation/Reoxygenation-Induced Neuronal Ferroptosis by Activating Nrf2/SLC7A11/GPX4 Axis

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 923
Author(s):  
Yuan Yuan ◽  
Yanyu Zhai ◽  
Jingjiong Chen ◽  
Xiaofeng Xu ◽  
Hongmei Wang
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Antioxidant Capacity ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
Related Factor ◽  
Protective Effects

Kaempferol has been shown to protect cells against cerebral ischemia/reperfusion injury through inhibition of apoptosis. In the present study, we sought to investigate whether ferroptosis is involved in the oxygen-glucose deprivation/reperfusion (OGD/R)-induced neuronal injury and the effects of kaempferol on ferroptosis in OGD/R-treated neurons. Western blot, immunofluorescence, and transmission electron microscopy were used to analyze ferroptosis, whereas cell death was detected using lactate dehydrogenase (LDH) release. We found that OGD/R attenuated SLC7A11 and glutathione peroxidase 4 (GPX4) levels as well as decreased endogenous antioxidants including nicotinamide adenine dinucleotide phosphate (NADPH), glutathione (GSH), and superoxide dismutase (SOD) in neurons. Notably, OGD/R enhanced the accumulation of lipid peroxidation, leading to the induction of ferroptosis in neurons. However, kaempferol activated nuclear factor-E2-related factor 2 (Nrf2)/SLC7A11/GPX4 signaling, augmented antioxidant capacity, and suppressed the accumulation of lipid peroxidation in OGD/R-treated neurons. Furthermore, kaempferol significantly reversed OGD/R-induced ferroptosis. Nevertheless, inhibition of Nrf2 by ML385 blocked the protective effects of kaempferol on antioxidant capacity, lipid peroxidation, and ferroptosis in OGD/R-treated neurons. These results suggest that ferroptosis may be a significant cause of cell death associated with OGD/R. Kaempferol provides protection from OGD/R-induced ferroptosis partly by activating Nrf2/SLC7A11/GPX4 signaling pathway.

Abstract 204: HAX-1: A Novel Regulator of Energetics and Oxidative Stress in the Heart

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Chi K Lam ◽  
Wen Zhao ◽  
Wenfeng Cai ◽  
Guansheng Liu ◽  
Phil Bidwell ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Calcium Handling ◽  
Calcium Kinetics ◽  
Atp Production ◽  
Homologous Protein ◽  
Induced Apoptosis ◽  
Factor C

Sarcoplasmic reticulum (SR) calcium handling is central not only in the control of heart function during excitation-contraction coupling but also in mitochondrial energetics and apoptosis. Recent studies have identified the anti-apoptotic protein, HS-1 associated protein X-1 (HAX-1) as a novel regulator of SR calcium cycling. Although HAX-1 has been shown to localize to mitochondria in various tissues, we found out that it also localizes to SR through its interaction with phospholamban (PLN) in cardiac muscle. Acute or chronic overexpression of HAX-1 in cardiomyocytes promoted PLN inhibition on the calcium ATPase (SERCA) and decreased cardiomyocyte calcium kinetics and contractile parameters. Accordingly, ablation of HAX-1 significantly enhanced SERCA activity and calcium kinetics. Furthermore, the HAX-1/PLN interaction appeared to also regulate cardiomyocyte survival. Indeed, overexpression of HAX-1 and the associated depressed SR Ca-load attenuated endoplasmic reticulum stress induced apoptosis, as evidenced by reduction of both caspase-12 activation and pro-apoptotic transcription factor C/EBP homologous protein induction during ischemia/reperfusion injury. In addition, the depressed SR Ca-cycling by HAX-1 overexpression was associated with reduced mitochondrial Ca-load as reflected by: a) hyper-phosphorylation of pyruvate dehydrogenase (PDH) and decreases in its activity, to diminish ATP production consistent with the attenuated energetic demand in these hearts; and b) reduced levels of reactive oxygen species, indicating protection from oxidative damage and preserved mitochondrial integrity. These findings suggest that HAX-1 is a key regulator of Ca-cycling, apoptosis and energetics in the heart. Thus, decreases in HAX-1 levels, observed during ischemia/reperfusion injury, may contribute to the deteriorated function and progression to heart failure development.

Abstract 205: Recovery from Ischemia-Reperfusion Injury Is Metabolic Substrate-Dependent

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Sergiy M Nadtochiy ◽  
Paul S Brookes
Keyword(s):  
Cell Death ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Lactate Production ◽  
Protective Role ◽  
Reserve Capacity ◽  
Similar Response ◽  
Fat Cells ◽  
Metabolic Reserve

Introduction: The adult heart utilizes mostly fat for energy production, with adaptation to different fuels (“metabolic plasticity”) being a hallmark of the healthy heart. However, metabolic maladaptation is known to occur in heart failure. As such, the ability of the heart to metabolize specific substrates could impact the outcome of pathological insults, such as ischemia-reperfusion (IR) injury. The aim of this study was to develop a system whereby adult mouse cardiomyocytes (AMC) subjected to IR injury could be supplied with different fuels, and metabolism measured in real-time. Methods: AMC were divided in 3 groups, supplied either with glucose (GLU, 5mM), palmitate/fat free BSA (FAT, 100µM) or GLU+FAT. A previously developed method for in-vitro IR injury using a Seahorse XF24 [1], was adopted for ACM. IR comprised 60 min. ischemia and 60 min. reperfusion, and additional metabolic parameters were measured separately using mitochondrial inhibitors and uncouplers [2]. Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were simultaneously measured during the IR protocol, followed by a cell death assay. Results: FAT cells showed higher baseline OCR and lower ECAR rates compare to GLU cells, although uncoupled OCR was lower in FAT group, suggesting a lower metabolic reserve capacity for cells respiring on fat. Upon IR, the drop in pH was significantly greater in GLU compare to FAT, indicating faster lactate production. During reperfusion, both OCR and ECAR recovered to pre-ischemic levels in GLU cells but failed to do so in FAT cells. Post-IR cell death was significantly higher in FAT vs. GLU. Surprisingly, GLU+FAT (modeling a “physiologic” substrate mix) replicated the same metabolic profile and cell death as GLU. Conclusions: (i) AMC had better recovery from IR injury using glucose as fuel. (ii) Lower cell viability in FAT (vs. GLU) correlated with smaller metabolic reserve capacity and with a smaller pH drop during ischemia. This is consistent with a known protective role for acidification during IR injury. (iii) Mixed substrates (GLU+FAT) gave a similar response to glucose alone, suggesting that fat may not be toxic, rather glucose is protective, in IR injury. [1] Circ Res. (2012), 110. 948-57. [2] J Vis Exp. (2010), 46. pii: 2511.

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