-
Archives of Biochemistry and Biophysics May 2022Mitochondria change their morphology and inner membrane structure depending on their activity. Since mitochondrial activity also depends on their structure, it is...
Mitochondria change their morphology and inner membrane structure depending on their activity. Since mitochondrial activity also depends on their structure, it is important to elucidate the interrelationship between the activity and structure of mitochondria. However, the mechanism by which mitochondrial activity affects the structure of cristae, the folded structure of the inner membrane, is not well understood. In this study, the effect of the mitochondrial activity on the cristae structure was investigated by examining the structural rigidity of cristae. Taking advantage of the fact that unfolding of cristae induces mitochondrial swelling, we investigated the relationship between mitochondrial activity and the susceptibility to swelling. The swelling of individual isolated mitochondria exposed to a hypotonic solution was observed with an optical microscope. The presence of respiratory substrates (malate and glutamate) increased the percentage of mitochondria that underwent swelling, and the further addition of rotenone or KCN (inhibitors of proton pumps) reversed the increase. In the absence of respiratory substrates, acidification of the buffer surrounding the mitochondria also increased the percentage of swollen mitochondria. These observations suggest that acidification of the outer surface of inner membranes, especially intracristal space, by proton translocation from the matrix to the intracristal space, decreases the structural rigidity of the cristae. This interpretation was verified by the observation that ADP or CCCP, which induces proton re-entry to the matrix, suppressed the mitochondrial swelling in the presence of respiratory substrates. The addition of CCCP to the cells induced a morphological change in mitochondria from an initial elongated structure to a largely curved structure at pH 7.4, but there were no morphological changes when the pH of the cytosol dropped to 6.2. These results suggest that a low pH in the intracristal space may be helpful in maintaining the elongated structure of mitochondria. The present study shows that proton pumping by the electron transfer chain is the mechanism underlying mitochondrial morphology and the flexibility of cristae structure.
Topics: Carbonyl Cyanide m-Chlorophenyl Hydrazone; Mitochondria; Mitochondrial Membranes; Proton Pumps; Protons
PubMed: 35276212
DOI: 10.1016/j.abb.2022.109172 -
Biochemical and Biophysical Research... Sep 2023Calcium overload performs a crucial function in the pathogenesis of myocardial ischemia-reperfusion (I/R) damage, which contributes to mitochondrial impairment and...
Calcium overload performs a crucial function in the pathogenesis of myocardial ischemia-reperfusion (I/R) damage, which contributes to mitochondrial impairment and apoptosis of cardiomyocytes. Suberoylanilide hydroxamic acid (SAHA), a small molecule histone deacetylases inhibitor with modulatory capacity on Na-Ca exchanger (NCX), is proven to have protective potential towards cardiac remodeling and injury, but the mechanism remains unclear. Hence, Hence, our present research explored the modulation of NCX-Ca-CaMKII by SAHA in myocardial I/R damage. Our outcomes indicate that in vitro hypoxia and reoxygenation models of myocardial cells, SAHA treatment inhibited the increase in expression of NCX1, intracellular Ca concentration, expression of CaMKII and self-phosphorylated CaMKII, and cell apoptosis. In addition, SAHA treatment improved myocardial cell mitochondrial swelling inhibited mitochondrial membrane potential diminution and the openness of the mitochondrial permeability transition pore, and protected against mitochondrial dysfunction following I/R injury. In vivo, SAHA treatment alleviated the decrease in FS% and EF%, the increase in the myocardial infarct area, and myocardial enzyme levels caused by I/R injury, while also reducing myocardial cell apoptosis, and inhibiting mitochondrial fission and mitochondrial membrane rupture. These results indicated that SAHA treatment alleviated myocardial cell apoptosis as well as mitochondrial dysfunction resulting from myocardial I/R impairment, and contributed to myocardial function recovery by inhibiting the NCX-Ca-CaMKII pathway. These findings offered additional theoretical support to explore the mechanism of SAHA as a therapeutic agent in cardiac I/R damage and develop new treatment strategies.
Topics: Humans; Vorinostat; Histone Deacetylase Inhibitors; Myocardial Reperfusion Injury; Sodium-Calcium Exchanger; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Myocytes, Cardiac; Apoptosis
PubMed: 37300940
DOI: 10.1016/j.bbrc.2023.05.120 -
Biochimica Et Biophysica Acta.... Oct 2022Plant mitochondria are sensitive organelles affected by changing environmental stressors. Upon heat shock or the presence of reactive oxygen species, plant mitochondria... (Review)
Review
Plant mitochondria are sensitive organelles affected by changing environmental stressors. Upon heat shock or the presence of reactive oxygen species, plant mitochondria undergo in vivo morphological derangements associated with the extensively characterized opening of the mitochondrial permeability transition pore. Nevertheless, the classic mitochondrial permeability transition is known to be triggered by calcium overload causing mitochondrial swelling and dysfunction. Here we review evidence concerning calcium handling, permeability transition and mitochondrial impairments in plants, supporting the notion that the mitochondrial morphology transition is an in vivo indicator of the permeability transition.
Topics: Calcium; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Permeability
PubMed: 35772521
DOI: 10.1016/j.bbabio.2022.148586 -
JHEP Reports : Innovation in Hepatology Nov 2023Mitochondrial permeability transition pore (mPTP) opening is critical for mediating cell death during hepatic ischaemia-reperfusion injury (IRI). Blocking mPTP opening...
BACKGROUND & AIMS
Mitochondrial permeability transition pore (mPTP) opening is critical for mediating cell death during hepatic ischaemia-reperfusion injury (IRI). Blocking mPTP opening by inhibiting cyclophilin D (CypD) is a promising pharmacological approach for the treatment of IRI. Here, we show that diastereoisomers of a new class of small-molecule cyclophilin inhibitors (SMCypIs) have properties that make them attractive candidates for the development of therapeutic agents against liver IRI.
METHODS
Derivatives of the parent SMCypI were synthesised and evaluated for their ability to inhibit CypD peptidyl-prolyl - isomerase (PPIase) activity and for their mitoprotective properties, evaluated by measuring mitochondrial swelling and calcium retention capacity in liver mitochondria. The ability of the selected compounds to inhibit mPTP opening was evaluated in cells subjected to hypoxia/reoxygenation using a calcein/cobalt assay. Their ability to inhibit cell death was evaluated in cells subjected to hypoxia/reoxygenation by measuring lactate dehydrogenase (LDH) release, propidium iodide staining, and cell viability. The compound performing best was selected for efficacy evaluation in a mouse model of hepatic IRI.
RESULTS
The two compounds that showed the strongest inhibition of CypD PPIase activity and mPTP opening, C105 and C110, were selected. Their SR diastereoisomers carried the activity of the racemic mixture and exhibited mitoprotective properties superior to those of the known macrocyclic cyclophilin inhibitors cyclosporin A and alisporivir. C105SR was more potent than C110SR in inhibiting mPTP opening and prevented cell death in a model of hypoxia/reoxygenation. Finally, C105SR substantially protected against hepatic IRI by reducing hepatocyte necrosis and apoptosis.
CONCLUSIONS
We identified a novel cyclophilin inhibitor with strong mitoprotective properties both and that represents a promising candidate for cellular protection in hepatic IRI.
IMPACT AND IMPLICATIONS
Hepatic ischaemia-reperfusion injury (IRI) is one of the main causes of morbidity and mortality during or after liver surgery. However, no effective therapies are available to prevent or treat this devastating syndrome. An attractive strategy to prevent hepatic IRI aims at reducing cell death by targeting mitochondrial permeability transition pore opening, a phenomenon regulated by cyclophilin D. Here, we identified a new small-molecule cyclophilin inhibitor, and demonstrated the enhanced mitoprotective and hepatoprotective properties of one of its diastereoisomers both and , making it an attractive lead compound for subsequent clinical development.
PubMed: 37860051
DOI: 10.1016/j.jhepr.2023.100876 -
Glia Sep 2020Mitochondrial fission mediated by cytosolic dynamin related protein 1 (Drp1) is essential for mitochondrial quality control but may contribute to apoptosis as well....
Mitochondrial fission mediated by cytosolic dynamin related protein 1 (Drp1) is essential for mitochondrial quality control but may contribute to apoptosis as well. Blockade of Drp1 with mitochondrial division inhibitor 1 (mdivi-1) provides neuroprotection in several models of neurodegeneration and cerebral ischemia and has emerged as a promising therapeutic drug. In oligodendrocytes, overactivation of AMPA-type ionotropic glutamate receptors (AMPARs) induces intracellular Ca overload and excitotoxic death that contributes to demyelinating diseases. Mitochondria are key to Ca homeostasis, however it is unclear how it is disrupted during oligodendroglial excitotoxicity. In the current study, we have analyzed mitochondrial dynamics during AMPAR activation and the effects of mdivi-1 on excitotoxicity in optic nerve-derived oligodendrocytes. Sublethal AMPAR activation triggered Drp1-dependent mitochondrial fission, whereas toxic AMPAR activation produced Drp1-independent mitochondrial swelling. Accordingly, mdivi-1 efficiently inhibited Drp1-mediated mitochondrial fission and did not prevent oligodendrocyte excitotoxicity. Unexpectedly, mdivi-1 also induced mitochondrial depolarization, ER Ca depletion and modulation of AMPA-induced Ca signaling. These off-target effects of mdivi-1 sensitized oligodendrocytes to excitotoxicity and ER stress and eventually produced oxidative stress and apoptosis. Interestingly, in cultured astrocytes mdivi-1 induced nondetrimental mitochondrial depolarization and oxidative stress that did not cause toxicity or sensitization to apoptotic stimuli. In summary, our results provide evidence of Drp1-mediated mitochondrial fission during activation of ionotropic glutamate receptors in oligodendrocytes, and uncover a deleterious and Drp1-independent effect of mdivi-1 on mitochondrial and ER function in these cells. These off-target effects of mdivi-1 limit its therapeutic potential and should be taken into account in clinical studies.
Topics: Apoptosis; Dynamins; Homeostasis; Mitochondria; Mitochondrial Dynamics; Oligodendroglia; Quinazolinones; Receptors, Ionotropic Glutamate; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
PubMed: 32060978
DOI: 10.1002/glia.23802 -
Phytomedicine : International Journal... Sep 2023A proprietary Chinese herbal product called Dan-Deng-Tong-Nao softgel capsule (DDTNC) is used to treat ischemic stroke. However, the preventive mechanisms of DDTNC...
Dan-Deng-Tong-Nao softgel capsule promotes angiogenesis of cerebral microvasculature to protect cerebral ischemia reperfusion injury via activating HIF-1α-VEGFA-Notch1 signaling pathway.
BACKGROUND
A proprietary Chinese herbal product called Dan-Deng-Tong-Nao softgel capsule (DDTNC) is used to treat ischemic stroke. However, the preventive mechanisms of DDTNC against cerebral ischemia reperfusion injury (CIRI) haven not been characterized.
OBJECTIVE
To explore the mechanisms of protective effects of DDTNC against CIRI from both internal and external levels.
METHODS
Chemical characterization was performed using UPLC. The potential protective mechanisms of DDTNC against CIRI were predicted using network pharmacology. Model of middle cerebral artery occlusion/reperfusion (MCAO/R) was established in rats. An model of brain microvascular endothelial cells (BMECs) induced by oxygen-glucose deprivation/reoxygenation (OGD/R) was also established. We evaluated neurological deficits, cerebral infarct volume, cortical neuron damage, and mitochondrial swelling in vivo. We evaluated the expression of VEGFR2, VEGFA, HIF-1α, CD31, and CD34 in ischemic cortex, and VEGF, bFGF, BDNF, angiostatin, and endostatin in serum of rats and in BMEC supernatants. We also evaluated cell viability, cytotoxicity, intracellular ROS, apoptosis, and migration ability in vitro.
RESULTS
Seven components were detected in DDTNC. KEGG enrichment analysis showed that DDTNC may modulate angiogenesis via the HIF-1 signaling pathway. DDTNC treatment reduced neurological score and infarct volume, and improved cell morphology of damaged neurons. Transmission electron microscopy showed that DDTNC reduced mitochondria swelling in cortical neurons. Furthermore, DDTNC reduced intracellular ROS and inhibited apoptosis. DDTNC boosted the expression of CD31, CD34, VEGFR2, VEGFA and HIF-1α, highlighting its involvement in angiogenesis, according to immunofluorescence studies. Furthermore, DDTNC enhanced tube formation and migration of BMECs in vitro. ELISA and western blotting indicated that DDTNCCSF induced the expression of VEGF, BDNF and bFGF, reduced the level of angiostatin and endostatin, increased the protein expression of VEGFA, Notch1 and HIF-1α in vitro and in vivo.
CONCLUSIONS
DDTNC promoted angiogenesis to protect brain tissue against MCAO/R, and exerted protective effects against OGD/R in BMECs via activating HIF-1α-VEGFA-NOTCH1 signal transduction pathway.
Topics: Rats; Animals; Endothelial Cells; Vascular Endothelial Growth Factor A; Angiostatins; Brain-Derived Neurotrophic Factor; Endostatins; Reactive Oxygen Species; Signal Transduction; Brain Ischemia; Infarction, Middle Cerebral Artery; Reperfusion Injury; Microvessels; Receptor, Notch1
PubMed: 37487254
DOI: 10.1016/j.phymed.2023.154966 -
Journal of Biochemical and Molecular... Jul 2022Mitochondrial dysfunction and oxidative stress are identified to contribute to the mechanisms responsible for the pathogenesis of Alzheimer's disease (AD). Scopolamine...
Mitochondrial dysfunction and oxidative stress are identified to contribute to the mechanisms responsible for the pathogenesis of Alzheimer's disease (AD). Scopolamine (SCO) as a potent drug for inducing memory and learning impairment is associated with mitochondrial dysfunction and oxidative stress. In AD clinical trials molecules with antioxidant properties have shown modest benefit. Betanin as a multifunctional molecule with powerful antioxidative properties may be effective in the treatment of neurodegenerative. Hence, this study was designed to investigate the possible therapeutic effect of betanin against SCO-induced AD on Wistar rats. SCO (1 mg/kg) was administrated intraperitoneally to induce the AD in Wistar rats. The rats were treated with betanin doses (25 mg/kg and 50 mg/kg) intraperitoneally for 9 consecutive days. At the end of the 9th day, the animals were subjected to behavioral examination such as novel object recognition and passive avoidance tests and killed to study the mitochondrial and histological parameters. The results showed attenuation of SCO-induced memory and learning impairment by betanin at 50 mg/kg dose. Also, mitochondrial toxicity parameters such as mitochondrial membrane potential collapse, mitochondrial swelling, decreased activity of succinate dehydrogenase, and reactive oxygen species (ROS) production were reversed by betanin (50 mg/kg) compared to the SCO group. In addition, the ameliorative effect of betanin against SCO was demonstrated in histopathological results of hippocampus. The present investigation established that the betanin ameliorates the SCO-induced memory impairments, tissue injuries, and mitochondrial dysfunction by reducing mitochondrial ROS, which may be due to the potent antioxidant action of betanin.
Topics: Alzheimer Disease; Animals; Antioxidants; Betacyanins; Mitochondria; Oxidative Stress; Rats; Rats, Wistar; Reactive Oxygen Species; Scopolamine
PubMed: 35411685
DOI: 10.1002/jbt.23076 -
Archives of Biochemistry and Biophysics Dec 2020Organic acidurias (OADs) are inherited disorders of amino acid metabolism biochemically characterized by accumulation of short-chain carboxylic acids in tissues and... (Review)
Review
Organic acidurias (OADs) are inherited disorders of amino acid metabolism biochemically characterized by accumulation of short-chain carboxylic acids in tissues and biological fluids of the affected patients and clinically by predominant neurological manifestations. Some of these disorders are amenable to treatment, which significantly decreases mortality and morbidity, but it is still ineffective to prevent long-term neurologic and systemic complications. Although pathogenesis of OADs is still poorly established, recent human and animal data, such as lactic acidosis, mitochondrial morphological alterations, decreased activities of respiratory chain complexes and altered parameters of oxidative stress, found in tissues from patients and from genetic mice models with these diseases indicate that disruption of critical mitochondrial functions and oxidative stress play an important role in their pathophysiology. Furthermore, organic acids that accumulate in the most prevalent OADs were shown to compromise bioenergetics, by decreasing ATP synthesis, mitochondrial membrane potential, reducing equivalent content and calcium retention capacity, besides inducing mitochondrial swelling, reactive oxygen and nitrogen species generation and apoptosis. It is therefore presumed that secondary mitochondrial dysfunction and oxidative stress caused by major metabolites accumulating in OADs contribute to tissue damage in these pathologies.
Topics: Amino Acid Metabolism, Inborn Errors; Animals; Brain; Carboxylic Acids; Humans; Mitochondria; Nervous System Diseases; Oxidative Stress
PubMed: 33098870
DOI: 10.1016/j.abb.2020.108646 -
Acta Pharmacologica Sinica Oct 2020Heart failure (HF) represents one of the leading causes of cardiovascular diseases with high rates of hospitalization, morbidity and mortality worldwide. Ample evidence... (Review)
Review
Heart failure (HF) represents one of the leading causes of cardiovascular diseases with high rates of hospitalization, morbidity and mortality worldwide. Ample evidence has consolidated a crucial role for mitochondrial injury in the progression of HF. It is well established that mitochondrial Ca participates in the regulation of a wide variety of biological processes, including oxidative phosphorylation, ATP synthesis, reactive oxygen species (ROS) generation, mitochondrial dynamics and mitophagy. Nonetheless, mitochondrial Ca overload stimulates mitochondrial permeability transition pore (mPTP) opening and mitochondrial swelling, resulting in mitochondrial injury, apoptosis, cardiac remodeling, and ultimately development of HF. Moreover, mitochondria possess a series of Ca transport influx and efflux channels, to buffer Ca in the cytoplasm. Interaction at mitochondria-associated endoplasmic reticulum membranes (MAMs) may also participate in the regulation of mitochondrial Ca homeostasis and plays an essential role in the progression of HF. Here, we provide an overview of regulation of mitochondrial Ca homeostasis in maintenance of cardiac function, in an effort to identify novel therapeutic strategies for the management of HF.
Topics: Adenosine Triphosphate; Animals; Apoptosis; Calcium; Endoplasmic Reticulum; Heart Failure; Homeostasis; Humans; Intracellular Membranes; Mitochondria; Mitophagy; Necrosis; Reactive Oxygen Species
PubMed: 32694759
DOI: 10.1038/s41401-020-0476-5 -
BMC Pharmacology & Toxicology Apr 2023Medical therapies can cause cardiotoxicity. Chloroquine (QC) and hydroxychloroquine (HQC) are drugs used in the treatment of malaria and skin and rheumatic disorders....
BACKGROUND
Medical therapies can cause cardiotoxicity. Chloroquine (QC) and hydroxychloroquine (HQC) are drugs used in the treatment of malaria and skin and rheumatic disorders. These drugs were considered to help treatment of coronavirus disease (COVID-19) in 2019. Despite the low cost and availability of QC and HQC, reports indicate that this class of drugs can cause cardiotoxicity. The mechanism of this event is not well known, but evidence shows that QC and HQC can cause cardiotoxicity by affecting mitochondria and lysosomes.
METHODS
Therefore, our study was designed to investigate the effects of QC and HQC on heart mitochondria. In order to achieve this aim, mitochondrial function, reactive oxygen species (ROS) level, mitochondrial membrane disruption, and cytochrome c release in heart mitochondria were evaluated. Statistical significance was determined using the one-way and two-way analysis of variance (ANOVA) followed by post hoc Tukey to evaluate mitochondrial succinate dehydrogenase (SDH) activity and cytochrome c release, and Bonferroni test to evaluate the ROS level, mitochondrial membrane potential (MMP) collapse, and mitochondrial swelling.
RESULTS
Based on ANOVA analysis (one-way), the results of mitochondrial SDH activity showed that the IC concentration for CQ is 20 µM and for HCQ is 50 µM. Based on two-way ANOVA analysis, the highest effect of CQ and HCQ on the generation of ROS, collapse in the MMP, and mitochondrial swelling were observed at 40 µM and 100 µM concentrations, respectively (p < 0.05). Also, the highest effect of these two drugs has been observed in 60 min (p < 0.05). The statistical results showed that compared to CQ, HCQ is able to cause the release of cytochrome c from mitochondria in all applied concentrations (p < 0.05).
CONCLUSIONS
The results suggest that QC and HQC can cause cardiotoxicity which can lead to heart disorders through oxidative stress and disfunction of heart mitochondria.
Topics: Humans; Hydroxychloroquine; Chloroquine; Reactive Oxygen Species; Cardiotoxicity; Cytochromes c; COVID-19; COVID-19 Drug Treatment; Mitochondria
PubMed: 37085872
DOI: 10.1186/s40360-023-00666-x