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The Journal of Toxicological Sciences 2017The herb Ephedra sinica (also known as Chinese ephedra or Ma Huang), used in traditional Chinese medicine, contains alkaloids identical to ephedrine and pseudoephedrine...
The herb Ephedra sinica (also known as Chinese ephedra or Ma Huang), used in traditional Chinese medicine, contains alkaloids identical to ephedrine and pseudoephedrine as its principal active constituents. Recent studies have reported that ephedrine has various side effects in the cardiovascular and nervous systems. In addition, herbal Ephedra, a plant containing many pharmacologically active alkaloids, principally ephedrine, has been reported to cause acute hepatitis. Many studies reported clinical cases, however, the cellular mechanism of liver toxicity by ephedrine remains unknown. In this study, we investigated hepatotoxicity and key regulation of mitophagy in ephedrine-treated LX-2 cells. Ephedrine triggered mitochondrial oxidative stress and depolarization. Mitochondrial swelling and autolysosome were observed in ephedrine-treated cells. Ephedrine also inhibited mitochondrial biogenesis, and the mitochondrial copy number was decreased. Parkin siRNA recovered the ephedrine-induced mitochondrial damage. Excessive mitophagy lead to cell death through imbalance of autophagic flux. Moreover, antioxidants and reducing Parkin level could serve as therapeutic targets for ephedrine-induced hepatotoxicity.
Topics: Antioxidants; Autophagy; Cell Death; Cells, Cultured; Chemical and Drug Induced Liver Injury; Ephedra sinica; Ephedrine; Gene Dosage; Hepatic Stellate Cells; Humans; Lysosomes; Mitochondria, Liver; Mitochondrial Swelling; Mitophagy; Molecular Targeted Therapy; Organelle Biogenesis; Oxidative Stress; RNA, Small Interfering; Ubiquitin-Protein Ligases
PubMed: 28717105
DOI: 10.2131/jts.42.461 -
Acta Biochimica Et Biophysica Sinica Jan 2019Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmosis. Previous studies have shown that the perturbation of mitochondrial metabolism in T....
Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmosis. Previous studies have shown that the perturbation of mitochondrial metabolism in T. gondii results in growth deficiency in host cells and lack of virulence in animals. Members of this Letm1 protein family are inner mitochondrial membrane proteins which play a role in potassium and hydrogen ion exchange. Letm1 has not been characterized in T. gondii. In this study, a potential TgLetm1 gene (TgGT1_288400) with Letm1-like protein domain coding sequence was identified in T. gondii. Indirect immunofluorescence assays suggested that TgLetm1 localized to the mitochondria in tachyzoites, as indicated by the colocalization with mitochondrial marker Mitotracker. TgLetm1 was found in the membrane fraction by western blot analysis. To investigate the role of TgLetm1 in T. gondii, we generated a tetracycline-inducible TgLetm1-knock-down mutant. The conditional deletion of TgLetm1 resulted in mitochondrial swelling. Functional studies showed that the conditional deletion of TgLetm1 resulted in growth inhibition, deficiency in invasion and replication, and lack of virulence in mice.
Topics: Animals; Chlorocebus aethiops; Host-Parasite Interactions; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Mitochondrial Membranes; Mitochondrial Proteins; Mitochondrial Swelling; Mutation; Protozoan Proteins; Survival Analysis; Toxoplasma; Toxoplasmosis, Animal; Vero Cells; Virulence
PubMed: 30423025
DOI: 10.1093/abbs/gmy138 -
Asian Pacific Journal of Tropical... Oct 2013To evaluate the antioxidant and radical scavenging activities of Solanum anguivi fruit (SAG) and its possible effect on mitochondrial permeability transition pore as...
African eggplant (Solanum anguivi Lam.) fruit with bioactive polyphenolic compounds exerts in vitro antioxidant properties and inhibits Ca(2+)-induced mitochondrial swelling.
OBJECTIVE
To evaluate the antioxidant and radical scavenging activities of Solanum anguivi fruit (SAG) and its possible effect on mitochondrial permeability transition pore as well as mitochondrial membrane potential (ΔΨm) isolated from rat liver.
METHODS
Antioxidant activity of SAG was assayed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, iron chelation and ability to inhibit lipid peroxidation in both liver and brain homogenate of rats. Also, the effect of SAG on mitochondrial membrane potential and mitochondrial swelling were determined. Identification and quantification of bioactive polyphenolics was done by HPLC-DAD.
RESULTS
SAG exhibited potent and concentration dependent free radical-scavenging activity (IC50/DPPH=275.03±7.8 μg/mL). Reductive and iron chelation abilities also increase with increase in SAG concentration. SAG also inhibited peroxidation of cerebral and hepatic lipids subjected to iron oxidative assault. SAG protected against Ca(2+) (110 μmol/L)-induced mitochondrial swelling and maintained the ΔΨm. HPLC analysis revealed the presence of gallic acid [(17.54±0.04) mg/g], chlorogenic acid (21.90±0.02 mg/g), caffeic acid (16.64±0.01 mg/g), rutin [(14.71±0.03) mg/g] and quercetin [(7.39±0.05) mg/g].
CONCLUSIONS
These effects could be attributed to the bioactive polyphenolic compounds present in the extract. Our results suggest that SAG extract is a potential source of natural antioxidants that may be used not only in pharmaceutical and food industry but also in the treatment of diseases associated with oxidative stress.
Topics: Animals; Antioxidants; Calcium; Fruit; Iron Chelating Agents; Lipid Peroxidation; Male; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Oxidation-Reduction; Permeability; Phenols; Plant Extracts; Polyphenols; Rats; Solanum
PubMed: 24075339
DOI: 10.1016/S2221-1691(13)60152-5 -
Scientific Reports Jul 2017Mitochondrial integrity is critical for the regulation of cellular energy and apoptosis. Metformin is an energy disruptor targeting complex I of the respiratory chain....
Mitochondrial integrity is critical for the regulation of cellular energy and apoptosis. Metformin is an energy disruptor targeting complex I of the respiratory chain. We demonstrate that metformin induces endoplasmic reticulum (ER) stress, calcium release from the ER and subsequent uptake of calcium into the mitochondria, thus leading to mitochondrial swelling. Metformin triggers the disorganization of the cristae and inner mitochondrial membrane in several cancer cells and tumors. Mechanistically, these alterations were found to be due to calcium entry into the mitochondria, because the swelling induced by metformin was reversed by the inhibition of mitochondrial calcium uniporter (MCU). We also demonstrated that metformin inhibits the opening of mPTP and induces mitochondrial biogenesis. Altogether, the inhibition of mPTP and the increase in mitochondrial biogenesis may account for the poor pro-apoptotic effect of metformin in cancer cells.
Topics: Animals; Calcium; Cell Line, Tumor; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Energy Metabolism; Humans; Metformin; Mice; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Models, Biological; Organelle Biogenesis
PubMed: 28698627
DOI: 10.1038/s41598-017-05052-2 -
The Journal of Biological Chemistry Nov 1985The amount of light scattered by a mitochondrial suspension depends on matrix volume (Tedeschi, H., and Harris, D.L. (1955) Arch. Biochem. Biophys. 58, 52-67), a...
The amount of light scattered by a mitochondrial suspension depends on matrix volume (Tedeschi, H., and Harris, D.L. (1955) Arch. Biochem. Biophys. 58, 52-67), a correlation which has been extensively exploited for qualitative studies of solute transport across the inner membrane. To obtain reliable, quantitative estimates of solute transport, it is first necessary to characterize the factors determining mitochondrial light scattering. We show that the dependence of absorbance on mitochondrial concentration can be linearized, resulting in an intrinsic light scattering parameter which is independent of the concentration and source of mitochondria. We show that the absorbance osmotic curve is segmentally linear, exhibiting discontinuities which disappear irreversibly following preswelling. In contrast, direct measurements reveal matrix volume to be reversibly and linearly dependent on inverse osmolality. This divergence is a consequence of the fact that the optical technique samples total particle volume, including contributions from folded membranes and trapped medium. These contributions are minimized by structural components, such as intermembrane connections and the outer membrane, which contribute to efficient packaging of the mitochondrion. When these structures are broken, the mitochondrion cannot return to its native state. We observe that the swelling-induced, irreversible transition from efficient packaging to a random packing state begins at a matrix volume of 1.9 microliter/mg and is complete at 3.1 microliter/mg. These findings complicate the interpretation of light scattering results but do not appear to present an insurmountable obstacle to the quantitative application of this technique to transport kinetics.
Topics: Animals; Biological Transport; Colorimetry; In Vitro Techniques; Kinetics; Light; Male; Mitochondria; Mitochondrial Swelling; Osmolar Concentration; Rats; Rats, Inbred Strains; Scattering, Radiation; Tetraethylammonium Compounds
PubMed: 4055741
DOI: No ID Found -
The Journal of Biological Chemistry Nov 1985The relationship between matrix volume and the amount of light scattered by a mitochondrial suspension has been characterized for equilibrium measurements and shown to...
The relationship between matrix volume and the amount of light scattered by a mitochondrial suspension has been characterized for equilibrium measurements and shown to depend in a complex but predictable manner on native structure of the mitochondrion (Beavis, A. D., Brannan, R. D., and Garlid, K. D. (1985) J. Biol. Chem. 260, 13424-13433). In the present report, we show that this characterization also applies to kinetic measurements of salt and nonelectrolyte transport. We derive and evaluate quantitative methods for determining permeability constants from light scattering kinetics. We apply these equations to the problem of whether matrix swelling itself induces permeability changes secondary to membrane stretching or changes in surface available for transport. A study of erythritol transport over a 7-fold range of matrix volume reveals dramatic changes in light scattering rates, as previously observed (Tedeschi, H. (1959) J. Biophys. Biochem. Cytol. 6, 241-252). These transitions correspond exactly to structure-dependent transitions in the relationship between absorbance and matrix volume. When this is taken into account, erythritol permeability is found to be constant over the entire volume range. Factors affecting intrinsic membrane porters, such as Mg2+ depletion and dicyclohexylcarbodiimide, are also found to be without effect on erythritol permeability. The broader significance of this study is that the light scattering technique is shown to be capable of providing quantitative answers to important questions about solute transport across the inner membrane.
Topics: Animals; Biological Transport; Colorimetry; Dicyclohexylcarbodiimide; Erythritol; In Vitro Techniques; Kinetics; Light; Magnesium; Male; Mitochondria; Mitochondrial Swelling; Osmolar Concentration; Quinine; Rats; Rats, Inbred Strains; Scattering, Radiation; Thiocyanates
PubMed: 4055742
DOI: No ID Found -
The Journal of Biophysical and... Jan 1959The in vitro swelling action of L-thyroxine on rat liver mitochondria as examined photometrically represents an acceleration of a process which the mitochondria are...
The in vitro swelling action of L-thyroxine on rat liver mitochondria as examined photometrically represents an acceleration of a process which the mitochondria are already inherently capable of undergoing spontaneously, as indicated by the identical kinetic characteristics and the extent of thyroxine-induced and spontaneous swelling, the nearly identical pH dependence, and the fact that sucrose has a specific inhibitory action on both types of swelling. However, thyroxine does not appear to be a "catalyst" or coenzyme since it does not decrease the temperature coefficient of spontaneous swelling. The temperature coefficient is very high, approximately 6.0 near 20 degrees . Aging of mitochondria at 0 degrees causes loss of thyroxine sensitivity which correlates closely with the loss of bound DPN from the mitochondria, but not with loss of activity of the respiratory chain or with the efficiency of oxidative phosphorylation. Tests with various respiratory chain inhibitors showed that the oxidation state of bound DPN may be a major determinant of thyroxine sensitivity; the oxidation state of the other respiratory carriers does not appear to influence sensitivity to thyroxine. These facts and other considerations suggest that a bound form of mitochondrial DPN is the "target" of the action of thyroxine. The thyroxine-induced swelling is not reversed by increasing the osmolar concentration of external sucrose, but can be "passively" or osmotically reversed by adding the high-particle weight solute polyvinylpyrrolidone. The mitochondrial membrane becomes more permeable to sucrose during the swelling reaction. On the other hand, thyroxine-induced swelling can be "actively" reversed by ATP in a medium of 0.15 M KCl or NaCl but not in a 0.30 M sucrose medium. The action of ATP is specific; ADP, Mn(++), and ethylenediaminetetraacetate are not active. It is concluded that sucrose is an inhibitor of the enzymatic relationship between oxidative phosphorylation and the contractility and permeability properties of the mitochondrial membrane. Occurrence of different types of mitochondrial swelling, the intracellular factors affecting the swelling and shrinking of mitochondria, as well as the physiological significance of thyroxine-induced swelling are discussed.
Topics: Animals; Liver; Mitochondria; Mitochondria, Liver; Mitochondrial Swelling; Osmolar Concentration; Oxidation-Reduction; Oxidative Phosphorylation; Permeability; Rats; Thyroxine
PubMed: 13630940
DOI: 10.1083/jcb.5.1.97 -
PloS One 2013Calreticulin is a Ca(2+)-binding chaperone of the endoplasmic reticulum which regulates the signal transducer and activator of transcription 3 (STAT3). The effects of...
BACKGROUND
Calreticulin is a Ca(2+)-binding chaperone of the endoplasmic reticulum which regulates the signal transducer and activator of transcription 3 (STAT3). The effects of the calreticulin-STAT3 signaling pathway on cardiac mitochondria and on the progress of dilated cardiomyopathy (DCM) are still unclear.
METHODS AND RESULTS
The DCM model was generated in rats by the daily oral administration of furazolidone. Echocardiographic and hemodynamic studies demonstrated enlarged LV dimensions and reduced systolic and diastolic functions at thirty weeks after the first furazolidone administration. Morphometric analysis showed significant myocardial degeneration, interstitial fibrosis, and mitochondrial swelling with fractured or dissolved cristae in the model group. Compared with the control group, the mitochondrial membrane potential (MMP) level of the freshly isolated cardiac mitochondria and the enzyme activities of cytochrome c oxidase and succinate dehydrogenase in the model group were significantly decreased (P<0.05). Real-time PCR and western-blot revealed the increased expression of calreticulin associated with decreased activity of STAT3 in the model group. When cultured neonatal rat cardiomyocytes were exposed to furazolidone, a dose-dependent decrease in cell viability and MMP, and the increase of apoptosis rate were observed. The mRNA and protein expression of CRT gradually increased with the increase of furazolidone concentration, associated with a gradual decrease of the STAT3 phosphorylation level both in the whole cell and mitochondrial fraction. When calreticulin was knocked down with siRNA in cardiomyocytes, these changes of cardiomyocytes and mitochondria induced by furazolidone were significantly attenuated.
CONCLUSIONS
A rat model of DCM induced by furazolidone is successfully established. The calreticulin-STAT3 signaling pathway is involved in cardiac mitochondrial injury and the progress of furazolidone induced DCM.
Topics: Animals; Animals, Newborn; Apoptosis; Blotting, Western; Calreticulin; Cardiomyopathy, Dilated; Cell Survival; Cells, Cultured; Disease Models, Animal; Dose-Response Relationship, Drug; Electron Transport Complex IV; Furazolidone; Humans; Male; Membrane Potential, Mitochondrial; Mitochondria, Heart; Mitochondrial Swelling; Myocytes, Cardiac; RNA Interference; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; STAT3 Transcription Factor; Signal Transduction; Succinate Dehydrogenase
PubMed: 23818963
DOI: 10.1371/journal.pone.0066779 -
Experimental Physiology Jul 2011In both 3,5,3-triiodothyronine (T(3))-induced hyperthyroidism and cold-induced functional hyperthyroidism, the heart displays an increased susceptibility to oxidative...
In both 3,5,3-triiodothyronine (T(3))-induced hyperthyroidism and cold-induced functional hyperthyroidism, the heart displays an increased susceptibility to oxidative challenge in vitro. Hearts from T(3)-treated rats also exhibit an increased susceptibility to ischaemia-reperfusion, a condition that raises free radical production. The present study was designed to establish whether cold-exposed rats exhibit an increased cardiac susceptibility to ischaemia-reperfusion which can be attenuated by vitamin E. The following four groups of animals were used: C, control rats (n = 8, temperature 24°C); C+VE, vitamin E-treated rats (n = 8, temperature 24°C); CE, cold-exposed rats (n = 8, temperature 4°C); and CE+VE, cold-exposed vitamin E-treated rats (n = 8, temperature 4°C). Langendorff preparations from these animals were submitted to 20 min ischaemia followed by 25 min reperfusion. At the end of the ischaemia-reperfusion protocol, homogenates and mitochondria were prepared and used for analytical procedures. With respect to control hearts, cold hearts showed a lower inotropic recovery and a higher oxidative stress, as inferred by higher levels of oxidized proteins and lipids and lower reduced glutathione levels. These changes were prevented when cold rats were treated with vitamin E. Evidence was also obtained that mitochondria are involved in the tissue derangement of cold hearts. Indeed, they display a faster production of reactive oxygen species, which causes mitochondrial oxidative damage and functional decline that parallel the tissue dysfunction. Moreover, vitamin E-linked improvement of tissue function was associated with a lower oxidative damage and a restored function of mitochondria. Finally, the mitochondrial population composition and Ca(2+)-induced swelling data indicate that the decline in mitochondrial function is in part due to a decrease in the amount of the highly functional heavy mitochondria linked to their higher susceptibility to oxidative damage and swelling. In conclusion, our work shows that vitamin E treatment attenuates harmful side-effects of the cardiac response to cold, such as oxidative damage and susceptibility to oxidants, thus preserving mitochondrial function and tissue recovery from ischaemia-reperfusion.
Topics: Animals; Calcium; Cold Temperature; Heart; Hydrogen Peroxide; Hyperthyroidism; Male; Mitochondria, Heart; Mitochondrial Swelling; Myocardial Reperfusion Injury; Oxidative Stress; Oxygen Consumption; Rats; Rats, Wistar; Vitamin E
PubMed: 21527542
DOI: 10.1113/expphysiol.2011.058289 -
International Journal of Molecular... May 2018Excessive generation of reactive oxygen species (ROS) in mitochondria and the opening of the nonselective mitochondrial permeability transition pore are important...
Excessive generation of reactive oxygen species (ROS) in mitochondria and the opening of the nonselective mitochondrial permeability transition pore are important factors that promote cardiac pathologies and dysfunction. The hormone melatonin (MEL) is known to improve the functional state of mitochondria via an antioxidant effect. Here, the effect of MEL administration on heart mitochondria from aged rats with acute cardiac failure caused by isoprenaline hydrochloride (ISO) was studied. A histological analysis revealed that chronic intake of MEL diminished the age-dependent changes in the structure of muscle fibers of the left ventricle, muscle fiber swelling, and injury zones characteristic of acute cardiac failure caused by ISO. In acute heart failure, the respiratory control index (RCI) and the Ca retention capacity in isolated rat heart mitochondria (RHM) were reduced by 30% and 40%, respectively, and mitochondrial swelling increased by 34%. MEL administration abolished the effect of ISO. MEL partially prevented ISO-induced changes at the subunit level of respiratory complexes III and V and drastically decreased the expression of complex I subunit NDUFB8 both in control RHM and in RHM treated with ISO, which led to the inhibition of ROS production. MEL prevents the mitochondrial dysfunction associated with heart failure caused by ISO. It was shown that the level of 2′,3′-cyclicnucleotide-3′-phosphodiasterase (CNPase), which is capable of protecting cells in aging, increased in acute heart failure. MEL also retained the CNPase content in RHM both in control experiments and after ISO-induced heart damage. We concluded that an increase in the CNPase level promotes cardioprotection.
Topics: 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase; Aging; Animals; Calcium; Cell Respiration; Cryoultramicrotomy; Electron Transport; Heart Failure; Heart Ventricles; Isoproterenol; Male; Melatonin; Mitochondria, Heart; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Rats, Wistar; Reactive Oxygen Species; Voltage-Dependent Anion Channels
PubMed: 29882895
DOI: 10.3390/ijms19061555