Mitochondrial Free Radical Research Articles

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.

A novel therapeutic application of solid lipid nanoparticles encapsulated thymoquinone (TQ-SLNs) on 3-nitroproponic acid induced Huntington’s disease-like symptoms in wistar rats

Huntington’s disease (HD), a devastating neurodegenerative disease causing a remarkable pathogenesis involves mitochondrial dysfunction and bioenergetics failure. 3-Nitropropionic acid (3-NP) is a unique toxin model of HD that are mainly confined to mitochondrial complex-II inhibition and free radical generation. Recently, several nanoparticle formulations were developed to treat against various neurodegenerative diseases including HD. One among them is solid lipid nanoparticles (SLNs), a colloidal carrier designed to enhance the brain drug delivery and to prolong the bio-availability of drugs in the system. Hence, the present study was framed to evaluate solid lipid nanoparticles encapsulated thymoquinone (TQ-SLNs) in comparison with thymoquinone suspension (TQ-S) against 3-NP induced behavioral despair, oxidative injury and striatal pathology. This study reports that theTQ-SLNs (10 and 20 mg/kg) and TQ-S (80 mg/kg) treated animals showed a significant (P < 0.01) improvement in the muscle strength, rigidity, movement and memory performances on 7th and 14th day behavioral analysis than TQ-S (40 mg/kg) treated group. Similarly, TQ-SLNs highly attenuated the levels of oxidative stress markers such as LPO, NO and protein carbonylsin 3-NP induced animals. Further, TQ-SLNs significantly restored the antioxidant defense system, controls the mitochondrial SDH inhibition and alleviates anti-cholinergic effect upon 3-NP induction. In addition, TQ-SLNs efficiently protected the striatal structural microelements against 3-NP toxicity, which was confirmed by light microscopic studies. Thus, the present investigation, collectively suggests that the low dose of TQ-SLNs supplementation is highly sufficient to attain the effect of TQ-S (80 mg/kg) to attenuate behavioral, biochemical and histological modifications in 3-NP exposed HD model.

Alcohol hangover: impairments in behavior and bioenergetics in central nervous system

Alcohol hangover (AH) is defined as the temporary state after alcohol binge-like drinking, starting when EtOH is absent in plasma. Results from our laboratory have shown behavioral impairments and mitochondrial dysfunction in an experimental model of AH in mice. Our model consisted in a single i.p. injection of EtOH (3.8 g/kg BW) or saline solution in male and female mice, sacrificing the animals 6 hours after injection. Motor and affective behavior together with mitochondrial function and free radical production were evaluated in brain cortex and cerebellum during AH. Results showed that hangover animals exhibited a significant reduction in neuromuscular coordination, motor strength and locomotion together with a loss of gait stability and walking deficiencies. Moreover, an increment in anxiety-like behavior together with fear-related phenotype and depression signs were observed. In relation to bioenergetics metabolism, AH induced a reduction in oxygen uptake, inhibition of respiratory complexes, changes in mitochondrial membrane permeability, decrease in transmembrane potential, increase in O2 •- and H2O2 production and impairment in nitric oxide metabolism. All together our data suggest that the physiopathological state of AH involves behavioral impairments and mitochondrial dysfunction in mouse brain cortex and cerebellum showing the long lasting effects of acute EtOH exposure in CNS.

Effects of inhalation of low-dose nitrite or carbon monoxide on post-reperfusion mitochondrial function and tissue injury in hemorrhagic shock swine.

IntroductionTissue reperfusion following hemorrhagic shock may paradoxically cause tissue injury and organ dysfunction by mitochondrial free radical expression. Both nitrite and carbon monoxide (CO) may protect from this reperfusion injury by limiting mitochondrial free radial production. We explored the effects of very small doses of inhaled nitrite and CO on tissue injury in a porcine model of hemorrhagic shock.MethodsTwenty pigs (mean wt. 30.6 kg, range 27.2 to 36.4 kg) had microdialysis catheters inserted in muscle, peritoneum, and liver to measure lactate, pyruvate, glucose, glycerol, and nitrite. Nineteen of the pigs were bled at a rate of 20 ml/min to a mean arterial pressure of 30 mmHg and kept between 30 and 40 mmHg for 90 minutes and then resuscitated. One pig was instrumented but not bled (sham). Hemorrhaged animals were randomized to inhale nothing (control, n = 7), 11 mg nitrite (nitrite, n = 7) or 250 ppm CO (CO, n = 5) over 30 minutes before fluid resuscitation. Mitochondrial respiratory control ratio was measured in muscle biopsies. Repeated measures from microdialysis catheters were analyzed in a random effects mixed model.ResultsNeither nitrite nor CO had any effects on the measured hemodynamic variables. Following inhalation of nitrite, plasma, but not tissue, nitrite increased. Following reperfusion, plasma nitrite only increased in the control and CO groups. Thereafter, nitrite decreased only in the nitrite group. Inhalation of nitrite was associated with decreases in blood lactate, whereas both nitrite and CO were associated with decreases in glycerol release into peritoneal fluid. Following resuscitation, the muscular mitochondrial respiratory control ratio was reduced in the control group but preserved in the nitrite and CO groups.ConclusionsWe conclude that small doses of nebulized sodium nitrite or inhaled CO may be associated with intestinal protection during resuscitation from severe hemorrhagic shock.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0903-z) contains supplementary material, which is available to authorized users.

Bcl11b: A New Piece to the Complex Puzzle of Amyotrophic Lateral Sclerosis Neuropathogenesis?

Amyotrophic lateral sclerosis (ALS) is an idiopathic, fatal, neurodegenerative disease of the human motor system. The pathogenesis of ALS is a topic of fascinating speculation and experimentation, with theories revolving around intracellular protein inclusions, mitochondrial structural issues, glutamate excitotoxicity and free radical formation. This review explores the rationale for the involvement of a novel protein, B-cell lymphoma/leukaemia 11b (Bcl11b) in ALS. Bcl11b is a multifunctional zinc finger protein transcription factor. It functions as both a transactivator and genetic suppressor, acting both directly, binding to promoter regions, and indirectly, binding to promoter-bound transcription factors. It has essential roles in the differentiation and growth of various cells in the central nervous system, immune system, integumentary system and cardiovascular system, to the extent that Bcl11b knockout mice are incompatible with extra-uterine life. It also has various roles in pathology including the suppression of latent retroviruses, thymic tumourigenesis and neurodegeneration. In particular its functions in neurodevelopment, viral latency and T-cell development suggest potential roles in ALS pathology.

Effects of different formulations of α-tocopherol acetate (vitamin E) on growth performance, meat quality and antioxidant capacity in broiler chickens

The objective of this study was to investigate and compare the effects of α-tocopherol acetate (vitamin E (VE)) and microencapsulated VE (MVE) on growth performance, meat quality and antioxidant capacity in broiler chickens.A total of 360 d-old broiler chicks were procured and randomly allocated into three groups with 6 replicates. Each replicate had 20 chickens. Chickens were fed with basal diets (CON group) or experimental diets supplemented with 20 mg/kg VE (VE group) or 20 mg/kg MVE (MVE group) for 42 d.The results showed that the MVE group had higher body weight gain (BWG) than the CON and VE groups, and higher gain/feed ratio (G/F ratio) than the CON group during the period of 22–42 d. During the whole experiment, a higher increase in BWG was found in the MVE group than the CON group.Chickens fed on diets supplemented with the VE or MVE had lower abdominal fat percentage, higher pH and antioxidant enzyme activity than the CON group in the breast meat.There was an increased tendency in the hepatic glutathione peroxidase (GSH-Px) enzyme activity of the VE and MVE groups than the CON group. The hepatic mitochondrial total antioxidant capacity and GSH-Px enzyme activity in the MVE group were higher than the CON group. Hepatic 2,2-dipheny-ʟ-picrylhydrazyl scavenging activity of the MVE group was higher than the CON group.These results suggested that the dietary addition of VE or MVE could improve breast meat quality in broilers. MVE supplementation may improve growth performance, hepatic mitochondrial antioxidant capacity and free radical scavenging capacity in chickens. In addition, dietary supplementation of MVE gave better broiler growth performance than VE.

Alcohol hangover induces mitochondrial dysfunction and free radical production in mouse cerebellum.

Alcohol hangover (AH) is defined as the temporary state after alcohol binge-like drinking, starting when ethanol (EtOH) is absent in plasma. Previous data indicate that AH induces mitochondrial dysfunction and free radical production in mouse brain cortex. The aim of this work was to study mitochondrial function and reactive oxygen species production in mouse cerebellum at the onset of AH. Male mice received a single i.p. injection of EtOH (3.8g/kg BW) or saline solution. Mitochondrial function was evaluated 6h after injection (AH onset). At the onset of AH, malate-glutamate and succinate-supported state 4 oxygen uptake was 2.3 and 1.9-fold increased leading to a reduction in respiratory control of 55% and 48% respectively, as compared with controls. Decreases of 38% and 16% were found in Complex I-III and IV activities. Complex II-III activity was not affected by AH. Mitochondrial membrane potential and mitochondrial permeability changes were evaluated by flow cytometry. Mitochondrial membrane potential and permeability were decreased by AH in cerebellum mitochondria. Together with this, AH induced a 25% increase in superoxide anion and a 92% increase in hydrogen peroxide production in cerebellum mitochondria. Related to nitric oxide (NO) metabolism, neuronal nitric oxide synthase (nNOS) protein expression was 52% decreased by the hangover condition compared with control group. No differences were found in cerebellum NO production between control and treated mice. The present work demonstrates that the physiopathological state of AH involves mitochondrial dysfunction in mouse cerebellum showing the long-lasting effects of acute EtOH exposure in the central nervous system.

Reconsidering the Role of Mitochondria in Aging.

Mitochondrial dysfunction has long been considered a major contributor to aging and age-related diseases. Harman's Mitochondrial Free Radical Theory of Aging postulated that somatic mitochondrial DNA mutations that accumulate over the life span cause excessive production of reactive oxygen species that damage macromolecules and impair cell and tissue function. Indeed, studies have shown that maximal oxidative capacity declines with age while reactive oxygen species production increases. Harman's hypothesis has been seriously challenged by recent studies showing that reactive oxygen species evoke metabolic health and longevity, perhaps through hormetic mechanisms that include autophagy. The purpose of this review is to scan the ever-growing literature on mitochondria from the perspective of aging research and try to identify priority questions that should be addressed in future research. A systematic search of peer-reviewed studies was performed using PubMed. Search terms included (i) mitochondria or mitochondrial; (ii) aging, ageing, older adults or elderly; and (iii) reactive oxygen species, mitochondria dynamics, mitochondrial proteostasis, cytosol, mitochondrial-associated membranes, redox homeostasis, electron transport chain, electron transport chain efficiency, epigenetic regulation, DNA heteroplasmy. The importance of mitochondrial biology as a trait d'union between the basic biology of aging and the pathogenesis of age-related diseases is stronger than ever, although the emphasis has moved from reactive oxygen species production to other aspects of mitochondrial physiology, including mitochondrial biogenesis and turnover, energy sensing, apoptosis, senescence, and calcium dynamics. Mitochondria could play a key role in the pathophysiology of aging or in the earlier stages of some events that lead to the aging phenotype. Therefore, mitochondria will increasingly be targeted to prevent and treat chronic diseases and to promote healthy aging.

SkQ-1 Regulates Xanthine Oxidase Activity in the Settings of Epilepsic Seizures in Rats

Interdependence between mitochondrial dysfunctions and synthesis of the free radicals during the epileptogenesis is proved by number of publications. Xanthine Oxidase (XO) might serve as a source of hydrogen peroxide synthesis, which by its turn is able to disturb the process of ATP generation in mitochondria. Antioxidants, such as Skulachev’s cations, might be used as possible inhibitors of XO and prevent the formation of free radicals in mitochondria. In our current work, we found out that SkQ-1 might inhibit the activity of XO in homogenate as well as in the purified fraction in vitro. In vivo modeling of epilepsy with the utility of korazol showed that the quantity of XO final product – uric acid, is elevating, whereas addition of SkQ-1 might suppress that increase in mitochondria. Keywords: ATP, epilepsy, mitochondria, SkQ-1, xanthine oxidase.

Intermittent Fasting with a High Fat Diet Reveals the Contribution of Mitochondrial Free Radicals to the Endothelium‐Dependent Relaxation of Mouse Aorta

Obesity leads to endothelial dysfunction, promoting age‐related cardiovascular diseases. In mice, a high fat diet (HFD) impairs endothelial function, while caloric restriction slows age‐dependent endothelial dysfunction and increases lifespan. Whether intermittent fasting (IF) influences endothelial function is unknown. Three‐month old C57BL6 mice were fed ad libitum (AL) or every other day (IF) either a regular diet (RD) or a HFD for 16 weeks. Caloric intake was similar in mice fed a RD either AL or in IF; however, RD‐IF prevented body weight gain (p&lt;.05), improved glucose tolerance and insulin sensitivity (p&lt;.05). As expected, HFD‐AL increased caloric intake (+27 %), body weight (+7 g), adipose tissue and liver weight (2 fold), glucose intolerance and insulin resistance (p&lt;.05). Combining HFD and IF reduced by 50 % the rise in caloric intake compared to HFD‐AL (p&lt;.05), fully prevented HFD‐induced gain in body weight, kept optimal (equal to RD‐IF) glucose tolerance, and normalized insulin sensitivity (p&lt;.05). Acetylcholine (Ach)‐induced relaxation was measured in isolated aortic rings. Ach‐induced maximal relaxation (Emax, see Table) was increased in HDF‐AL mice (p&lt;.05) due to a compensatory increase in eNOS activity. IF tended to ameliorate Emax (p=.06), irrespectively of the diet and without changing eNOS activity. In the 4 groups, TEMPOL (SOD mimetic) led to higher (p&lt;.05) vascular sensitivity and Emax to Ach. Interestingly, mitoTEMPO targeting mitochondria, reduced (p&lt;.05) endothelium‐dependent relaxation in HFD‐IF fed mice only, revealing the contribution of mitochondrial free radicals to the endothelium‐dependent relaxation of mouse aorta. Emax (%) RD‐AL HFD‐AL RD‐IF HFD‐IF Control 52 ± 6 78 ± 4 * 68 ± 5 68 ± 7 L‐NNA (eNOS inhibitor) 22 ± 7 $ 41 ± 10 $ 33 ± 10 $ 31 ± 13 $ TEMPOL (SOD mimetic) 95 ± 2 $ 90 ± 3 90 ± 4 $ 85 ± 5 mitoTEMPO (mitochondrial SOD2 mimetic) 66 ± 12 70 ± 6 66 ± 8 46 ± 8 $ data are presented as mean ± SEM; * p&amp;lt;0.05 vs. RD‐AL; $ p&amp;lt;0.05 vs. Control.

Mitochondrial free radical overproduction due to respiratory chain impairment in the brain of a mouse model of Rett syndrome: protective effect of CNF1

Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene associated with severe intellectual disability, movement disorders, and autistic-like behaviors. Its pathogenesis remains mostly not understood and no effective therapy is available. High circulating levels of oxidative stress markers in patients and the occurrence of oxidative brain damage in MeCP2-deficient mouse models suggest the involvement of oxidative stress in RTT pathogenesis. However, the molecular mechanism and the origin of the oxidative stress have not been elucidated. Here we demonstrate that a redox imbalance arises from aberrant mitochondrial functionality in the brain of MeCP2-308 heterozygous female mice, a condition that more closely recapitulates that of RTT patients. The marked increase in the rate of hydrogen peroxide generation in the brain of RTT mice seems mainly produced by the dysfunctional complex II of the mitochondrial respiratory chain. In addition, both membrane potential generation and mitochondrial ATP synthesis are decreased in RTT mouse brains when succinate, the complex II respiratory substrate, is used as an energy source. Respiratory chain impairment is brain area specific, owing to a decrease in either cAMP-dependent phosphorylation or protein levels of specific complex subunits. Further, we investigated whether the treatment of RTT mice with the bacterial protein CNF1, previously reported to ameliorate the neurobehavioral phenotype and brain bioenergetic markers in an RTT mouse model, exerts specific effects on brain mitochondrial function and consequently on hydrogen peroxide production. In RTT brains treated with CNF1, we observed the reactivation of respiratory chain complexes, the rescue of mitochondrial functionality, and the prevention of brain hydrogen peroxide overproduction. These results provide definitive evidence of mitochondrial reactive oxygen species overproduction in RTT mouse brain and highlight CNF1 efficacy in counteracting RTT-related mitochondrial defects.

Current perspectives on neonatal hypoglycemia, its management, and cerebral injury risk

Glucose is an essential substrate for mammalian cells; in particular, the brain needs glucose continuously as a primary source of energy. Hypoglycemia is the most common biochemical finding in the neonatal period. However, despite the common occurrence, there is still controversy on the definition of hypoglycemia in the newborn period. This has led to the development of guidelines designed to identify infants at-risk and the implementation of an operational threshold for physicians to consider intervention. In healthy term infants, the optimal hormonal and metabolic adaptations during the immediate neonatal period ensure an adequate energy substrate for the vital organs, whereas the abnormal glucose homeostasis observed in preterm and growth-retarded infants is multifactorial in origin. For these high-risk infants, it is important to identify, screen, and prevent significant hypoglycemia. Detailed investigations are warranted in infants with severe and persistent hypoglycemia. Neonatal hypo- glycemia is a major cause of brain injury. The speculated mechanisms of cellular injury include excitatory neurotoxins active at N-methyl-D-aspartate receptors, increased mitochondrial free radical generation with initiation of apoptosis and altered cerebral energetic characteristics. This hypoglycemic brain injury predominantly affects parieto-occipital regions causing cognitive, sensory, psychomotor, and behavioral deficits in children. This state of the art review article covers the fetal-neonatal metabolic adaptation, glucose homeostasis in normal and abnormal conditions, management strategies, and late neurological sequelae of hypoglycemia.

Mitochondrial fission and fusion in astrocytes: a new pathway towards senescence

Event Abstract Back to Event Mitochondrial fission and fusion in astrocytes: a new pathway towards senescence Sonia L. Albarracin1*, Bernd R. Stab1*, Maria C. Tovar1, Laura Martinez1 and Mabel A. Grismaldo1 1 Pontificia Universidad Javeriana, Nutrition and Biochemistry, Colombia Astrocytes are highly specialized cells that can maintain the integrity of the synapse, facilitate nutrition and trophic support to neurons, and regulate metabolic coupling between neurons and glia. However, astrocytes are involved in resolving different types of injuries and in aging processes in the brain. Senescence has also been reported in the brain, and senescence-associated loss of astrocyte function is linked to neuronal dysfunction in age-related neurodegenerative diseases such as Alzheimer’s disease and Parkinson's disease. For example, astrocyte senescence per se inhibits synapse maturation and affects synaptic transmission. In response to the cell’s bio-energetic state, mitochondria continuously undergo structural remodeling through fission and fusion processes. These tightly regulated events are believed to be involved in many cellular events such as apoptosis, senescence, and age-related diseases. Although, little is known about the age-related changes that occur in astrocytes and if these cells are able to generate a senescent phenotype mediated by mitochondria, in the present study we evaluated the involvement of mitochondrial remodeling in the senescence process of rat astrocytes in vitro. The results obtained showed that when comparing cells at population doubling two (PD2) with cells at population doubling ten (PD10) there is a significant increase in the activity of the senescence-associated β-galactosidase marker in PD10 cells. In addition, PD10 cells had increased mitochondrial volume, decreased superoxide production, and decreased mitochondrial membrane potential. Protein characterization evidenced changes in the balance between mitochondrial fission and fusion proteins. Collectively, our results demonstrated a senescent-astrocyte phenotype at PD10, which is associated with metabolic and mitochondrial phenotype changes. Acknowledgements This work was supported by grants Pontificia Universidad Javeriana ID 4468. References Andreyev, A.Y., Y.E. Kushnareva, and Starkov, A.A. (2005). Mitochondrial metabolism of reactive oxygen species. Biochemistry (Mosc). 70, 200-214. Griffin, E.E., S.A. Detmer, and Chan, D.C. (2006). Molecular mechanism of mitochondrial membrane fusion. Biochim Biophys Acta, 1763, 482-489. Hoppins, S., Lackner, L. and Nunnari, J. (2007). The machines that divide and fuse mitochondria. Annu Rev Biochem, 2007. 76, 751-780. Sanz, A. and Stefanatos, R.K. (2008). The mitochondrial free radical theory of aging: a critical view. Curr Aging Sci, 1, 10-21. Ziegler, D.V., Wiley, C.D., and Velarde, M.C. (2015). Mitochondrial effectors of cellular senescence: beyond the free radical theory of aging. Aging Cell, 14, 1-7. doi: 10.1111/acel.12287 Keywords: Aging, Astrocytes, Mitochondria, Reactive Oxygen Species, senescence, mitochondrial fission and fusion proteins, neurodegeneration Conference: Latin-American School on glial cells in the diseased brain (IBRO), Bogotá, Colombia, 13 Jul - 17 Jul, 2015. Presentation Type: Poster Presentation Topic: Neural excitability, synaptic transmission, glia: Cellular and molecular mechanisms Citation: Albarracin SL, Stab BR, Tovar MC, Martinez L and Grismaldo MA (2015). Mitochondrial fission and fusion in astrocytes: a new pathway towards senescence. Conference Abstract: Latin-American School on glial cells in the diseased brain (IBRO). doi: 10.3389/conf.fncel.2015.35.00030 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Feb 2015; Published Online: 11 Jun 2015. * Correspondence: Dr. Sonia L Albarracin, Pontificia Universidad Javeriana, Nutrition and Biochemistry, Bogota, D.C., Colombia, albarra@javeriana.edu.co Dr. Bernd R Stab, Pontificia Universidad Javeriana, Nutrition and Biochemistry, Bogota, D.C., Colombia, b.r.stab@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sonia L Albarracin Bernd R Stab Maria C Tovar Laura Martinez Mabel A Grismaldo Google Sonia L Albarracin Bernd R Stab Maria C Tovar Laura Martinez Mabel A Grismaldo Google Scholar Sonia L Albarracin Bernd R Stab Maria C Tovar Laura Martinez Mabel A Grismaldo PubMed Sonia L Albarracin Bernd R Stab Maria C Tovar Laura Martinez Mabel A Grismaldo Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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Tetrahydrocannabinol induces brain mitochondrial respiratory chain dysfunction and increases oxidative stress: a potential mechanism involved in cannabis-related stroke.

Cannabis has potential therapeutic use but tetrahydrocannabinol (THC), its main psychoactive component, appears as a risk factor for ischemic stroke in young adults. We therefore evaluate the effects of THC on brain mitochondrial function and oxidative stress, key factors involved in stroke. Maximal oxidative capacities V max (complexes I, III, and IV activities), V succ (complexes II, III, and IV activities), V tmpd (complex IV activity), together with mitochondrial coupling (V max/V 0), were determined in control conditions and after exposure to THC in isolated mitochondria extracted from rat brain, using differential centrifugations. Oxidative stress was also assessed through hydrogen peroxide (H2O2) production, measured with Amplex Red. THC significantly decreased V max (−71%; P < 0.0001), V succ (−65%; P < 0.0001), and V tmpd (−3.5%; P < 0.001). Mitochondrial coupling (V max/V 0) was also significantly decreased after THC exposure (1.8±0.2 versus 6.3±0.7; P < 0.001). Furthermore, THC significantly enhanced H2O2 production by cerebral mitochondria (+171%; P < 0.05) and mitochondrial free radical leak was increased from 0.01±0.01 to 0.10±0.01% (P < 0.001). Thus, THC increases oxidative stress and induces cerebral mitochondrial dysfunction. This mechanism may be involved in young cannabis users who develop ischemic stroke since THC might increase patient's vulnerability to stroke.

A panoramic overview of mitochondria and mitochondrial redox biology.

Mitochondria dysfunction was first described in the 1960s. However, the extent and mechanisms of mitochondria dysfunction’s role in cellular physiology and pathology has only recently begun to be appreciated. To adequately evaluate mitochondria-mediated toxicity, it is not only necessary to understand mitochondria biology, but discerning mitochondrial redox biology is also essential. The latter is intricately tied to mitochondrial bioenergetics. Mitochondrial free radicals, antioxidants, and antioxidant enzymes are players in mitochondrial redox biology. This review will provide an across-the-board, albeit not in-depth, overview of mitochondria biology and mitochondrial redox biology. With accumulating knowledge on mitochondria biology and mitochondrial redox biology, we may devise experimental methods with adequate sensitivity and specificity to evaluate mitochondrial toxicity, especially in vivo in living organisms, in the near future.

Mitochondrial catastrophe during doxorubicin-induced cardiotoxicity: a review of the protective role of melatonin.

Anthracyclines, such as doxorubicin, are among the most valuable treatments for various cancers, but their clinical use is limited due to detrimental side effects such as cardiotoxicity. Doxorubicin-induced cardiotoxicity is emerging as a critical issue among cancer survivors and is an area of much significance to the field of cardio-oncology. Abnormalities in mitochondrial functions such as defects in the respiratory chain, decreased adenosine triphosphate production, mitochondrial DNA damage, modulation of mitochondrial sirtuin activity and free radical formation have all been suggested as the primary causative factors in the pathogenesis of doxorubicin-induced cardiotoxicity. Melatonin is a potent antioxidant, is nontoxic, and has been shown to influence mitochondrial homeostasis and function. Although a number of studies support the mitochondrial protective role of melatonin, the exact mechanisms by which melatonin confers mitochondrial protection in the context of doxorubicin-induced cardiotoxicity remain to be elucidated. This review focuses on the role of melatonin on doxorubicin-induced bioenergetic failure, free radical generation, and cell death. A further aim is to highlight other mitochondrial parameters such as mitophagy, autophagy, mitochondrial fission and fusion, and mitochondrial sirtuin activity, which lack evidence to support the role of melatonin in the context of cardiotoxicity.

Effect of N-methyl-D-aspartic acid on activity of superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione level in selected organs of the mouse.

One of the major classes of ionotropic glutamate receptors is the class of N-methyl-D-aspartate receptors (NMDARs). Receptor activation recruits, via calcium signal transduction mechanisms which play important roles in oxidative metabolism, mitochondrial free radical production and occurrence of other mitochondrial factors which potentially contribute to excitotoxicity and neuronal death. In the present study, the effects of stimulation of NMDARs by applying N-methyl-D-aspartic acid (NMDA) in the brain, liver, kidneys and pancreas on change of the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) and in the amount of reduced glutathione (GSH) in blood, brain, liver and kidneys has been investigated. Statistically significant decrease of the activity of SOD, CAT and GSHPx and in the amount of reduced glutathione (GSH) was found in the examined organs after administration of NMDA, an agonist of NMDA receptors, demonstrating that NMDA administration compromises the antioxidant status in the investigated organs of the mouse.

Beta-nodavirus B2 protein induces hydrogen peroxide production, leading to Drp1-recruited mitochondrial fragmentation and cell death via mitochondrial targeting.

Because the role of the viral B2 protein in the pathogenesis of nervous necrosis virus infection remains unknown, the aim of the present study was to determine the effects of B2 protein on hydrogen peroxide (H2O2)-mediated cell death via mitochondrial targeting. Using a B2 deletion mutant, the B2 mitochondrial targeting signal sequence (41RTFVISAHAA50) correlated with mitochondrial free radical production and cell death in fish cells, embryonic zebrafish, and human cancer cells. After treatment of grouper fin cells (GF-1) overexpressing B2 protein with the anti-oxidant drug, N-acetylcysteine (NAC), and overexpression of the antioxidant enzymes, zfCu/Zn superoxide dismutase (SOD) and zfCatalase, decreased H2O2 production and cell death were observed. To investigate the correlation between B2 cytotoxicity and H2O2 production in vivo, B2 was injected into zebrafish embryos. Cell damage, as assessed by the acridine orange assay, gradually increased over 24 h post-fertilization, and was accompanied by marked increases in H2O2 production and embryonic death. Increased oxidative stress, as evidenced by the up-regulation of Mn SOD, catalase, and Nrf2, was also observed during this period. Finally, B2-induced dynamin-related protein 1 (Drp1)-mediated mitochondrial fragmentation and cell death could be reversed by NAC and inhibitors of Drp1 and Mdivi in GF-1 cells. Taken together, betanodavirus B2 induces H2O2 production via targeting the mitochondria, where it inhibits complex II function. H2O2 activates Drp1, resulting in its association with the mitochondria, mitochondrial fission and cell death in vitro and in vivo.

Mitochondria selective S-nitrosation by mitochondria-targeted S-nitrosothiol protects against post-infarct heart failure in mouse hearts.

AimsRecently it has been shown that the mitochondria-targeted S-nitrosothiol MitoSNO protects against acute ischaemia/reperfusion (IR) injury by inhibiting the reactivation of mitochondrial complex I in the first minutes of reperfusion of ischaemic tissue, thereby preventing free radical formation that underlies IR injury. However, it remains unclear how this transient inhibition of mitochondrial complex I-mediated free radicals at reperfusion affects the long-term recovery of the heart following IR injury. Here we determined whether the acute protection by MitoSNO at reperfusion prevented the subsequent development of post-myocardial infarction heart failure.Methods and resultsMice were subjected to 30 min left coronary artery occlusion followed by reperfusion and recovery over 28 days. MitoSNO (100 ng/kg) was applied 5 min before the onset of reperfusion followed by 20 min infusion (1 ng/kg/min). Infarct size and cardiac function were measured by magnetic resonance imaging (MRI) 24 h after infarction. MitoSNO-treated mice exhibited reduced infarct size and preserved function. In addition, MitoSNO at reperfusion improved outcome measures 28 days post-IR, including preserved systolic function (63.7 ±1.8% LVEF vs. 53.7 ± 2.1% in controls, P = 0.01) and tissue fibrosis.ConclusionsMitoSNO action acutely at reperfusion reduces infarct size and protects from post-myocardial infarction heart failure. Therefore, targeted inhibition of mitochondrial complex I in the first minutes of reperfusion by MitoSNO is a rational therapeutic strategy for preventing subsequent heart failure in patients undergoing IR injury.

The role of mitochondria in longevity and healthspan.

The role of mitochondria in aging and disease remains contentious more than 40 years after the mitochondrial free radical theory of aging was first proposed. As part of a wider cross-journal series on contemporary mitochondrial biology, Longevity & Healthspan presents a thematic series of four reviews that discuss the evidence for and against the modern incarnations of the theory, and examine the relevance of mitochondrial membrane phospholipid unsaturation and the interactions of mitochondria with sex hormones.