Inhibition Of Mitochondrial Oxidative Stress Research Articles

Nicotinamide riboside attenuates myocardial ischemia-reperfusion injury via regulating SIRT3/SOD2 signaling pathway

Ischemic heart disease invariably leads to devastating damage to human health. Nicotinamide ribose (NR), as one of the precursors of NAD+ synthesis, has been discovered to exert a protective role in various neurological and cardiovascular disorders. Our findings demonstrated that pretreatment with 200 mg/kg NR for 3 h significantly reduced myocardial infarct area, decreased levels of CK-MB and LDH in serum, and improved cardiac function in the rats during myocardial ischemia-reperfusion (I/R) injury. Meanwhile, 0.5 mM NR also effectively increased the viability and decreased the LDH release of H9c2 cells during OGD/R. We had provided evidence that NR pretreatment could decrease mitochondrial reactive oxygen species (mtROS) production and MDA content, and enhance SOD activity, thereby mitigating mitochondrial damage and inhibiting apoptosis during myocardial I/R injury. Further investigations revealed that NR increased NAD+ content and upregulated SIRT3 protein expression in myocardium. Through using of SIRT3 small interfering RNA and the SIRT3 deacetylase activity inhibitor 3-TYP, we had confirmed that the cardioprotective effect of NR on cardiomyocytes was largely dependent on the inhibition of mitochondrial oxidative stress via SIRT3-SOD2 axis. Overall, our study suggested that exogenous supplementation with NR mitigated mitochondrial damage and inhibited apoptosis during myocardial I/R injury by reducing mitochondrial oxidative stress via SIRT3-SOD2-mtROS pathway.

20(R)-ginsenoside Rg3 attenuates cerebral ischemia-reperfusion injury by mitigating mitochondrial oxidative stress via the Nrf2/HO-1 signaling pathway.

Reducing mitochondrial oxidative stress has become an important strategy to prevent neuronal death in ischemic stroke. Previous studies have shown that 20(R)-ginsenoside Rg3 can significantly improve behavioral abnormalities, reduce infarct size, and decrease the number of apoptotic neurons in cerebral ischemia/reperfusion injury rats. However, it remains unclear whether 20(R)-ginsenoside Rg3 can inhibit mitochondrial oxidative stress in ischemic stroke and the potential molecular mechanism. In this study, we found that 20(R)-ginsenoside Rg3 notably inhibited mitochondrial oxidative stress in middle cerebral artery occlusion/reperfusion (MCAO/R) rats and maintained the stability of mitochondrial structure and function. Treatment with 20(R)-ginsenoside Rg3 also decreased the levels of mitochondrial fission proteins (Drp1 and Fis1) and increased the levels of fusion proteins (Opa1, Mfn1, and Mfn2) in MCAO/R rats. Furthermore, we found that 20(R)-ginsenoside Rg3 promoted nuclear aggregation of nuclear factor erythroid2-related factor 2 (Nrf2) but did not affect Kelch-like ECH-associated protein-1 (Keap1), resulting in the downstream expression of antioxidants. In in vitro oxygen-glucose deprivation/reperfusion stroke models, the results of PC12 cells treated with 20(R)-ginsenoside Rg3 were consistent with animal experiments. After transfection with Nrf2 short interfering RNA (siRNA), the protective effect of 20(R)-ginsenoside Rg3 on PC12 cells was reversed. In conclusion, the inhibition of mitochondrial oxidative stress plays a vital position in the anti-cerebral ischemia-reperfusion injury of 20(R)-ginsenoside Rg3, and its neuroprotective mechanism is related to the activation of the nuclear factor erythroid2-related factor 2/heme oxygenase 1 signaling pathway.

Selenium Ameliorated Oxidized Fish Oil-Induced Lipotoxicity via the Inhibition of Mitochondrial Oxidative Stress, Remodeling of Usp4-Mediated Deubiquitination, and Stabilization of Pparα.

Aims: Studies demonstrated that oxidized fish oil (OFO) promoted oxidative stress and induced mitochondrial dysfunction and lipotoxicity, which attenuated beneficial effects of fish oil supplements in the treatment of nonalcoholic fatty liver disease (NAFLD). The current study was performed on yellow catfish, a good model to study NAFLD, and its hepatocytes to explore whether selenium (Se) could alleviate OFO-induced lipotoxicity via the inhibition of oxidative stress and determine its potential mechanism. Results: The analysis of triglycerides content, oxidative stress parameters, and histological and transmission electronic microscopy observation showed that high dietary Se supplementation alleviated OFO-induced lipotoxicity, oxidative stress, and mitochondrial injury and dysfunction. RNA-sequencing and immunoblotting analysis indicated that high dietary Se reduced OFO-induced decline of peroxisome-proliferator-activated receptor alpha (Pparα) and ubiquitin-specific protease 4 (Usp4) protein expression. High Se supplementation also alleviated OFO-induced reduction of thioredoxin reductase 2 (txnrd2) messenger RNA (mRNA) expression level and activity. The txnrd2 knockdown experiments revealed that txnrd2 mediated Se- and oxidized eicosapentaenoic acid (oxEPA)-induced changes of mitochondrial reactive oxygen species (mtROS) and further altered Usp4 mediated-deubiquitination and stabilization of Pparα, which, in turn, modulated mitochondrial fatty acid β-oxidation and metabolism. Mechanistically, Usp4 deubiquitinated Pparα and ubiquitin-proteasome-mediated Pparα degradation contributed to oxidative stress-induced mitochondrial dysfunction. Innovation: These findings uncovered a previously unknown mechanism by which Se and OFO interacted to affect lipid metabolism via the Txnrd2-mtROS-Usp4-Pparα pathway, which provides the new target for NAFLD prevention and treatment. Conclusion: Se ameliorated OFO-induced lipotoxicity via the inhibition of mitochondrial oxidative stress, remodeling of Usp4-mediated deubiquitination, and stabilization of Pparα. Antioxid. Redox Signal. 40, 433-452.

(226) Mito-Q, a Mitochondrial-targeted Antioxidant, Partially Improves Relaxation of the Corpus Cavernosum in Aged Diabetic Mice

Abstract Introduction Erectile dysfunction is associated with increased contraction and decreased relaxation of the corpus cavernosum (CC). Excessive reactive oxygen species produced by mitochondria play a key role in aging- and diabetes-induced erectile dysfunction. Erectile dysfunction is associated with increased contraction and decreased relaxation of the corpus cavernosum. Mitochondrial deterioration is part of normal physiological aging, and it plays a role in the pathogenesis of age-related disorders by producing reactive oxygen species (ROS). It is also known that excessive ROS produced by mitochondria plays a key role in aging- and diabetes-induced erectile dysfunction. Objective We aimed to test the hypothesis that in vitro inhibition of mitochondrial oxidative stress improves the reactivity of the CC. Methods To test this hypothesis, the CC of young (3 to 4-month-old) and old (10 to 14-month-old) male lean and diabetic (dbdb-/-) mice were mounted in myographs. Concentration-response curves to acetylcholine (ACh 1 nM – 30 uM) and relaxation induced by electrical field stimulation (EFS – 1, 2, 4, 8 and 16 Hz) were obtained. All curves were repeated after 30 minutes of incubation with the antioxidant Mito-Q (100 nM). Results Results: Relaxation to ACh was significantly reduced in the CC of diabetic mice (Lean: 87 ± 8% vs dbdb-/-: 60 ± 6%). Similarly, aged lean mice presented impaired relaxation to ACh (Lean old: 54 ± 6%) while old diabetic mice displayed a further decrease in the relaxing response to ACh (35 ± 6%). After 30 minutes of incubation with Mito-Q, the relaxation produced by ACh was improved in the CC of the aged lean mice (62 ± 3%) and aged diabetic mice (44 ± 1%). Relaxing responses to EFS were significantly decreased in obese and aged mice compared to the lean young animals. However, no improvement in the relaxing response to EFS was seen after incubation with Mito-Q. Conclusions Impairment in the endothelium-dependent relaxation of the CC induced by aging and diabetes is associated with increased production of mitochondrial reactive oxygen species. The use of the mitochondrial-targeted antioxidant Mito-Q improved at least in part the relaxation of the CC in both aged and diabetic mice. Disclosure No

Intermedin Alleviates Vascular Calcification in CKD through Sirtuin 3-Mediated Inhibition of Mitochondrial Oxidative Stress.

Vascular calcification (VC) is a common pathophysiological process of chronic kidney disease (CKD). Sirtuin 3 (Sirt3), a major NAD+-dependent protein deacetylase predominantly in mitochondria, is involved in the pathogenesis of VC. We previously reported that intermedin (IMD) could protect against VC. In this study, we investigated whether IMD attenuates VC by Sirt3-mediated inhibition of mitochondrial oxidative stress. A rat VC with CKD model was induced by the 5/6 nephrectomy plus vitamin D3. Vascular smooth muscle cell (VSMC) calcification was induced by CaCl2 and β-glycerophosphate. IMD1-53 treatment attenuated VC in vitro and in vivo, rescued the depressed mitochondrial membrane potential (MMP) level and decreased mitochondrial ROS levels in calcified VSMCs. IMD1-53 treatment recovered the reduced protein level of Sirt3 in calcified rat aortas and VSMCs. Inhibition of VSMC calcification by IMD1-53 disappeared when the cells were Sirt3 absent or pretreated with the Sirt3 inhibitor 3-TYP. Furthermore, 3-TYP pretreatment blocked IMD1-53-mediated restoration of the MMP level and inhibition of mitochondrial oxidative stress in calcified VSMCs. The attenuation of VSMC calcification by IMD1-53 through upregulation of Sirt3 might be achieved through activation of the IMD receptor and post-receptor signaling pathway AMPK, as indicated by pretreatment with an IMD receptor antagonist or AMPK inhibitor blocking the inhibition of VSMC calcification and upregulation of Sirt3 by IMD1-53. AMPK inhibitor treatment reversed the effects of IMD1-53 on restoring the MMP level and inhibiting mitochondrial oxidative stress in calcified VSMCs. In conclusion, IMD attenuates VC by improving mitochondrial function and inhibiting mitochondrial oxidative stress through upregulating Sirt3.

Neuroprotective Effects of VEGF-A Nanofiber Membrane and FAAH Inhibitor URB597 Against Oxygen-Glucose Deprivation-Induced Ischemic Neuronal Injury.

IntroductionBrain ischemia is a common neurological disorder worldwide that activates a cascade of pathophysiological events involving decreases in oxygen and glucose levels. Despite substantial efforts to explore its pathogenesis, the management of ischemic neuronal injury remains an enormous challenge. Accumulating evidence suggests that VEGF modified nanofiber (NF) materials and the fatty-acid amide hydrolase (FAAH) inhibitor URB597 exert an influence on alleviating ischemic brain damage. We aimed to further investigate their effects on primary hippocampal neurons, as well as the underlying mechanisms following oxygen–glucose deprivation (OGD).MethodsDifferent layers of VEGF-A loaded polycaprolactone (PCL) nanofibrous membranes were first synthesized by using layer-by-layer (LBL) self-assembly of electrospinning methods. The physicochemical and biological properties of VEGF-A NF membranes, and their morphology, hydrophilicity, and controlled-release of VEGF-A were then estimated. Furthermore, the effects of VEGF-A NF and URB597 on OGD-induced mitochondrial oxidative stress, inflammatory responses, neuronal apoptosis, and endocannabinoid signaling components were assessed.ResultsThe VEGF-A NF membrane and URB597 can not only promote hippocampal neuron adhesion and viability following OGD but also exhibited antioxidant/anti-inflammatory and mitochondrial membrane potential protection. The VEGF-A NF membrane and URB597 also inhibited OGD-induced cellular apoptosis through activating CB1R signaling. These results indicate that VEGF-A could be controlled-released by LBL self-assembled NF membranes.DiscussionThe VEGF-A NF membrane and URB597 displayed positive synergistic neuroprotective effects through the inhibition of mitochondrial oxidative stress and activation of CB1R/PI3K/AKT/BDNF signaling, suggesting that a VEGF-A loaded NF membrane and the FAAH inhibitor URB597 could be of therapeutic value in ischemic cerebrovascular diseases.

Mitochondrial Permeability Transition Pore Sealing Agents and Antioxidants Protect Oxidative Stress and Mitochondrial Dysfunction Induced by Naproxen, Diclofenac and Celecoxib

Nonsteroidal anti-inflammatory drugs (NSAIDs) like naproxen, diclofenac and celecoxib used to reduce pain. Many of these drugs have been associated with an increased risk of cardiovascular disease (CVD). The molecular mechanism(s) by which NSAIDs induce CVD up to now is unknown. We investigated the effects of naproxen, diclofenac and celecoxib with different structures and mechanism action on isolated rat heart mitochondria. All tested NSAIDs increased reactive oxygen species (ROS) formation, mitochondrial membrane collapse (MMP), mitochondrial swelling, lipid peroxidation, and glutathione and ATP depletion, which all of them play important roles in developing cardiotoxicity. We reported that mitochondrial permeability transition (MPT) pore sealing agents and antioxidants have the capacity to significantly prevent mitochondrial toxicity. Therefore, the inhibition of mitochondrial oxidative stress and mitochondrial dysfunction by MPT pore sealing agents and antioxidants can double confirm NSAID-induced cardiomyocytes toxicity is resulted from induction of apoptosis signaling trough ROS-mediated mitochondrial permeability transition.

Mitochondrial protective and antioxidant agents protect toxicity induced by depleted uranium in isolated human lymphocytes

Depleted uranium (DU) is a by-product of the enrichment procedure of natural uranium. During production and usage, uranium may be released into the environment due to failure to follow standard procedures, thus causing environmental pollution. In this study, toxicity effects of uranium (VI) and protective role of mitochondrial permeability transition pore sealing and antioxidant agents studied by isolated human lymphocytes. Human lymphocytes were exposed to different concentrations (0.1, 0.5, 1, 2 and 5 mM) of DU for 6 h and cytotoxicity was measured by trypan blue assay. The mechanistic parameters were assessed after 1, 2 and 3 h of lymphocyte treatment with 1/2 IC506h (0.3 mM), IC506h (0.8 mM) and 2 IC506h (1.6 mM) of DU. The reactive oxygen species (ROS), lysosomal membrane destabilization, mitochondrial membrane potential (MMP), lipid peroxidation, GSH and GSSG levels on human lymphocytes exposed to UA, were measured. The results indicate that toxicity of U (VI) was concentration dependent on human lymphocytes. Also, U (VI) induced ROS production, MMP reduction, lysosomal membrane destabilization and lipid peroxidation in human lymphocytes. In U (VI) treated lymphocytes, decrease in intracellular GSH and raise in extracellular GSSG levels were observed. We report that mitochondrial permeability transition (MPT) pore sealing and antioxidant agents, have the capacity significantly to prevents, mitochondrial toxicity. Thus, the inhibition of mitochondrial oxidative stress and mitochondrial dysfunction by MPT pore sealing and antioxidant agents is associated with the inhibition of DU-induced mitochondrial damages and activation of apoptosis in lymphocytes.

Eugenol attenuates concanavalin A-induced hepatitis through modulation of cytokine levels and inhibition of mitochondrial oxidative stress

Therapeutic management of hepatitis with conventional drugs alone worsens hepatic functioning in the long term because of sustained oxidative stress. Active compounds from several plant sources have been investigated to counteract this. Eugenol, a phytochemical abundant in various plants, is known for its wide range of pharmacological effects. There is a lacuna in the deeper understanding of its hepatoprotective activity at the molecular level. Our present study aimed to determine the effects of eugenol on the changes in antioxidant components, inflammatory cytokines and modulation of mitochondrial oxidative stress in immune-mediated hepatitis. We employed a model that mimics viral hepatitis using concanavalin A (ConA) to induce T-cell-mediated acute hepatitis. Eugenol increased (P<0.01) antioxidant enzyme activities, including reduced glutathione (GSH)-regenerating enzyme, glutathione reductase, and glucose-6-phosphate dehydrogenase. Its antiinflammatory and antifibrogenic effects were evident from the reduction (P<0.01) in interleukin and tumor necrosis factor levels. Eugenol was found to decrease mitochondrial oxidative stress, which was elevated in hepatitis. The hepatoprotective effects of eugenol were confirmed by histological findings. The current investigation shows that eugenol exerts a hepatoprotective effect through the modulation of different pathways which include restoration of mitochondrial oxidative stress. Eugenol could be a promising candidate for human hepatitis management, warranting preclinical studies.

Mulberry Fruit Extract Ameliorates Nonalcoholic Fatty Liver Disease (NAFLD) through Inhibition of Mitochondrial Oxidative Stress in Rats.

Mulberry is known to have pharmacological effects against cholesterol, obesity, and dyslipidemia. Many studies have revealed that mulberry leaf possesses hepatoprotective properties against nonalcoholic fatty liver disease (NAFLD); however, mulberry fruit is less studied in this context. Therefore, this study aimed to investigate the preventive effects of mulberry fruit against high fat diet- (HFD-) induced NAFLD. To evaluate the effects of mulberry fruit on NAFLD, two doses of mulberry fruit ethanol extracts [MB, 100, and 200 mg/kg BW (body weight)] were given to HFD-fed rats for 10 weeks. MB dramatically prevented liver damage as shown by biochemical analysis of the liver injury markers, alanine transaminase, and aspartate transaminase. MB treatment significantly inhibited the increased levels of total cholesterol, triacylglycerol, and low-density lipoprotein-cholesterol but restored the level of high-density lipoprotein-cholesterol in HFD-fed rats. Notably, histological analysis of liver tissues demonstrated that MB substantially ameliorated lipid accumulation. Expression of cholesterol-regulating genes was also suppressed by MB treatment. For its underlying mechanisms, MB suppressed hepatic reactive oxygen species (ROS) overproduction and mitochondrial oxidative stress in HFD-fed rats. MB potentially protects liver tissue against NAFLD by inhibition of mitochondrial oxidative stress, suggesting its possible use as a therapeutic agent for treatment of NAFLD.

Calorie restriction protects against apoptosis, mitochondrial oxidative stress and increased calcium signaling through inhibition of TRPV1 channel in the hippocampus and dorsal root ganglion of rats.

The TRPV1 channel is activated in neurons by capsaicin, oxidative stress, acidic pH and heat factors, and these factors are attenuated by the antioxidant role of calorie restriction (CR). Hence, we investigated the hypothesis that the antioxidant roles of CR and food frequency (FF) may modulate TRPV1 activity and apoptosis through inhibition of mitochondrial oxidative stress in hippocampal (HIPPON) and dorsal root ganglion neurons (DRGN). We investigated the contribution of FF and CR to neuronal injury and apoptosis through inhibition of TRPV1 in rats. We assigned rats to control, FF and FF + CR groups. A fixed amount of food ad libitum was supplemented to the control and FF groups for 20weeks, respectively. FF + CR group were fed the same amount of food as the control group but with 20% less calories during the same period. In major results, TRPV1 currents, intracellular Ca2+ levels, apoptosis, reactive oxygen species, mitochondrial depolarization, PARP-1 expression, caspase 3 and 9 activity and expression values were found to be increased in the HIPPON and DRGN following FF treatment, and these effects were decreased following FF + CR treatment. The FF-induced decrease in cell viability of HIPPO and DRGN, and vitamin E concentration of brain, glutathione peroxidase, vitamin A, and β-carotene values of the HIPPO, DRGN, plasma, liver and kidney were increased by FF + DR treatment, although lipid peroxidation levels in the same samples were decreased. In conclusion, CR reduces FF-induced increase of oxidative stress, apoptosis and Ca2+ entry through TRPV1 in the HIPPON and DRGN. Our findings may be relevant to the etiology and treatment of obesity following CR treatment.

The MKK7 inhibitor peptide GADD45β-I attenuates ER stress-induced mitochondrial dysfunction in HT22 cells: Involvement of JNK-Wnt pathway

JNK, a member of the mitogen activated protein kinases (MAPKs) superfamily, plays a key role in cell death in many neurological disorders, but systemic inhibition of JNK has detrimental side effects. JNK can be regulated by two direct upstream kinases: MAPK kinase 4 (MKK4) and MAPK kinase 7 (MKK7). Here, we investigated the effect of GADD45β-I, a recently designed cell-permeable inhibitor peptide for MKK7, on endoplasmic reticulum (ER) stress-induced cytotoxicity in neuronal HT22 cells. We found that treatment with the ER stress inducer tunicamycin (TM) increased the phosphorylation of JNK and MKK7 in HT22 cells, which was nullified by GADD45β-I. GADD45β-I significantly attenuated TM-induced toxicity via inhibiting apoptotic cell death, as evidenced by decreased number of TUNEL-positive cells and reduced caspase-3 activity. GADD45β-I treatment also decreased expression of ER stress associated pro-apoptotic proteins and prevented morphological changes of the ER after TM exposure. In addition, inhibition of mitochondrial oxidative stress and preservation of intracellular ATP levels were observed in GADD45β-I-treated cells. The experiments using siRNA transfection and Topflash reporter assay revealed a possible involvement of Wnt/β-catenin pathway in GADD45β-I-induced protection in HT22 cells. In summary, our results demonstrated that GADD45β-I exerted protective effects against TM-induced cytotoxicity via regulating JNK-Wnt pathway. Targeting MKK7 could represent a new therapeutic strategy for the treatment of neurological diseases where ER stress associated neuronal injury are involved.

Rotenone Protects Against Acetaminophen-Induced Kidney Injury by Attenuating Oxidative Stress and Inflammation

Background/Aims: In clinic, excessive acetaminophen (APAP) can cause kidney damage with uncertain mechanisms. Recently, accumulating evidence demonstrated a pathogenic role of mitochondrial dysfunction in the kidney injury. Thus, in this study, rotenone, a mitochondrial complex I inhibitor, was applied to the mice with APAP-induced acute kidney injury to evaluate the effect of mitochondrial complex I inhibition on APAP nephrotoxicity. Methods: After 3 days of rotenone pretreatment, mice were administered with APAP (300mg/kg) by intraperitoneal injection for 24 h. Then the kidney injury, inflammation, and oxidative stress were evaluated. Results: APAP significantly enhanced the BUN, serum creatine, and cystatin C levels in line with a moderate alteration of renal morphology. Strikingly, rotenone treatment normalized BUN, serum creatinine, and cystatin C levels, as well as the kidney morphology. Meanwhile, APAP enhanced tubular injury markers of NGAL and KIM-1 by 347- and 5-fold at mRNA levels, respectively. By Western blotting, we confirmed a 15-fold increment of NGAL in APAP-exposed kidneys. Importantly, rotenone treatment largely normalized NGAL and KIM-1 levels and attenuated inflammatory response in APAP-treated mice. Similarly, rotenone treatment enhanced the expressions of SOD1-3 compared with APAP group in line with a significant suppression of kidney MDA content. Finally, we observed that inhibition of mitochondrial complex III failed to protect against APAP-induced nephrotoxicity. Conclusion: Mitochondrial complex I inhibitor rotenone protected kidneys against APAP-induced injury possibly via the inhibition of mitochondrial oxidative stress and inflammation.

N-Methyl, N-propynyl-2-phenylethylamine (MPPE), a Selegiline Analog, Attenuates MPTP-induced Dopaminergic Toxicity with Guaranteed Behavioral Safety: Involvement of Inhibitions of Mitochondrial Oxidative Burdens and p53 Gene-elicited Pro-apoptotic Change.

Selegiline is a monoamine oxidase-B (MAO-B) inhibitor with anti-Parkinsonian effects, but it is metabolized to amphetamines. Since another MAO-B inhibitor N-Methyl, N-propynyl-2-phenylethylamine (MPPE) is not metabolized to amphetamines, we examined whether MPPE induces behavioral side effects and whether MPPE affects dopaminergic toxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Multiple doses of MPPE (2.5 and 5mg/kg/day) did not show any significant locomotor activity and conditioned place preference, whereas selegiline (2.5 and 5mg/kg/day) significantly increased these behavioral side effects. Treatment with MPPE resulted in significant attenuations against decreases in mitochondrial complex I activity, mitochondrial Mn-SOD activity, and expression induced by MPTP in the striatum of mice. Consistently, MPPE significantly attenuated MPTP-induced oxidative stress and MPPE-mediated antioxidant activity appeared to be more pronounced in mitochondrial-fraction than in cytosolic-fraction. Because MPTP promoted mitochondrial p53 translocation and p53/Bcl-xL interaction, it was also examined whether mitochondrial p53 inhibitor pifithrin-μ attenuates MPTP neurotoxicity. MPPE, selegiline, or pifithrin-μ significantly attenuated mitochondrial p53/Bcl-xL interaction, impaired mitochondrial transmembrane potential, cytosolic cytochrome c release, and cleaved caspase-3 in wild-type mice. Subsequently, these compounds significantly ameliorated MPTP-induced motor impairments. Neuroprotective effects of MPPE appeared to be more prominent than those of selegiline. MPPE or selegiline did not show any additional protective effects against the attenuation by p53 gene knockout, suggesting that p53 gene is a critical target for these compounds. Our results suggest that MPPE possesses anti-Parkinsonian potentials with guaranteed behavioral safety and that the underlying mechanism of MPPE requires inhibition of mitochondrial oxidative stress, mitochondrial translocation of p53, and pro-apoptotic process.

Rotenone remarkably attenuates oxidative stress, inflammation, and fibrosis in chronic obstructive uropathy.

Mitochondrial abnormality has been shown in many kidney disease models. However, its role in the pathogenesis of chronic kidney diseases (CKDs) is still uncertain. In present study, a mitochondrial complex I inhibitor rotenone was applied to the mice subjected to unilateral ureteral obstruction (UUO). Following 7-days rotenone treatment, a remarkable attenuation of tubular injury was detected by PAS staining. In line with the improvement of kidney morphology, rotenone remarkably blunted fibrotic response as shown by downregulation of fibronectin (FN), plasminogen activator inhibitor-1 (PAI-1), collagen I, collagen III, and α-SMA, paralleled with a substantial decrease of TGF-β 1. Meanwhile, the oxidative stress markers thiobarbituric acid-reactive substances (TBARS) and heme oxygenase 1 (HO-1) and inflammatory markers TNF-α, IL-1β, and ICAM-1 were markedly decreased. More importantly, the reduction of mitochondrial DNA copy number and mitochondrial NADH dehydrogenase subunit 1 (mtND1) expression in obstructed kidneys was moderately but significantly restored by rotenone, suggesting an amelioration of mitochondrial injury. Collectively, mitochondrial complex I inhibitor rotenone protected kidneys against obstructive injury possibly via inhibition of mitochondrial oxidative stress, inflammation, and fibrosis, suggesting an important role of mitochondrial dysfunction in the pathogenesis of obstructive kidney disease.

Specific inhibition of mitochondrial oxidative stress suppresses inflammation and improves cardiac function in a rat pneumonia-related sepsis model

Using a mitochondria-targeted vitamin E (Mito-Vit-E) in a rat pneumonia-related sepsis model, we examined the role of mitochondrial reactive oxygen species in sepsis-mediated myocardial inflammation and subsequent cardiac contractile dysfunction. Sepsis was produced in adult male Sprague-Dawley rats via intratracheal injection of S. pneumonia (4 × 10(6) colony formation units per rat). A single dose of Mito-Vit-E, vitamin E, or control vehicle, at 21.5 μmol/kg, was administered 30 min postinoculation. Blood was collected, and heart tissue was harvested at various time points. Mito-Vit-E in vivo distribution was confirmed by mass spectrometry. In cardiac mitochondria, Mito-Vit-E improved total antioxidant capacity and suppressed H(2)O(2) generation, whereas vitamin E offered little effect. In cytosol, both antioxidants decreased H(2)O(2) levels, but only vitamin E strengthened antioxidant capacity. Mito-Vit-E protected mitochondrial structure and function in the heart during sepsis, demonstrated by reduction in lipid and protein oxidation, preservation of mitochondrial membrane integrity, and recovery of respiratory function. While both Mito-Vit-E and vitamin E suppressed sepsis-induced peripheral and myocardial production of proinflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6), Mito-Vit-E exhibited significantly higher efficacy (P < 0.05). Stronger anti-inflammatory action of Mito-Vit-E was further shown by its near-complete inhibition of sepsis-induced myeloperoxidase accumulation in myocardium, suggesting its effect on neutrophil infiltration. Echocardiography analysis indicated that Mito-Vit-E ameliorated cardiac contractility of sepsis animals, shown by improved fractional shortening and ejection fraction. Together, our data suggest that targeted scavenging of mitochondrial reactive oxygen species protects mitochondrial function, attenuates tissue-level inflammation, and improves whole organ activities in the heart during sepsis.

Gallic acid prevents nonsteroidal anti-inflammatory drug-induced gastropathy in rat by blocking oxidative stress and apoptosis

Nonsteroidal anti-inflammatory drug (NSAID)-induced oxidative stress plays a critical role in gastric mucosal cell apoptosis and gastropathy. NSAIDs induce the generation of hydroxyl radical (•OH) through the release of free iron, which plays an important role in developing gastropathy. Thus, molecules having both iron-chelating and antiapoptotic properties will be beneficial in preventing NSAID-induced gastropathy. Gallic acid (GA), a polyphenolic natural product, has the capacity to chelate free iron. Here, we report that GA significantly prevents, as well as heals, NSAID-induced gastropathy. In vivo, GA blocks NSAID-mediated mitochondrial oxidative stress by preventing mitochondrial protein carbonyl formation, lipid peroxidation, and thiol depletion. In vitro, GA scavenges free radicals and blocks •OH-mediated oxidative damage. GA also attenuates gastric mucosal cell apoptosis in vivo as well as in vitro in cultured gastric mucosal cells as evident from the TUNEL assay. GA prevents NSAID-induced activation of caspase-9, a marker for the mitochondrial pathway of apoptosis, and restores NSAID-mediated collapse of the mitochondrial transmembrane potential and dehydrogenase activity. Thus, the inhibition of mitochondrial oxidative stress by GA is associated with the inhibition of NSAID-induced mitochondrial dysfunction and activation of apoptosis in gastric mucosal cells, which are responsible for gastric injury or gastropathy.

Abstract 3542: Role of Mitochondrial Oxidative Stress in Angiotensin II Mediated Hypertension

Oxidative stress is strongly implicated in the pathogenesis of hypertension; however, the role of mitochondrial oxidative stress is not clear. We have investigated the role of mitochondria in endothelial dysfunction and hypetention using cultured bovine endothelial cells (BAECs) and mice infused with angiotensin II (AngII). Production of O 2 •− was measured by dihydroethidium and HPLC. Nitric oxide and H 2 O 2 were detected by ESR. Sytolic blood presure was measured in mice infused with saline, AngII (0.7mg/kg/day), AngII plus mitochondria targeted antioxidant mitoTEMPO or non-targeted antioxidant TEMPOL (50 μg/kg/day). AngII significantly increased mitochondrial H 2 O 2 . MitoTEMPO blocked AngII-induced oxidative stress and restored NO • production in BAECs and mouse aorta. Supplementation of BAECs with malonate, inhibitor of complex II, or rotenone abolished AngII induced oxidative stress. Interestingly, inhibition of mitochondrial oxidative stress decreased the activity of NADPH oxidases. Co-infusion of mitoTEMPO with AngII significantly attenuated the increase in the blood pressure by 30-mm Hg (Fig. 1 ), while i.p. injection to hypertensive mice decreased the blood presure by 20-mm Hg. We suggest that mitoTEMPO can be used as an effective inhibitor of the oxidative stress induced by Ang II as well as an antihypertensive agent and, thereby, can be effective in ameliorating hypertension-related nephrosclerosis, diabetic nephropathy, or atherosclerosis. Figure 1. (A) Attenuation of hypertensive effect of Ang II in C57Blk/6 mice by co-infusion of mitoTEMPO. (B) Dose dependent effect of mitoTEMPO (50, 150 and 500 μg/kg/day) after 14-days of Ang II and drug administration. This research has received full or partial funding support from the American Heart Association, AHA National Center.

Mitochondrial Oxidative Stress, DNA Damage, and Heart Failure

Recent experimental and clinical studies have suggested that oxidative stress is enhanced in heart failure. The production of oxygen radicals is increased in the failing heart, whereas antioxidant enzyme activities are preserved as normal. Mitochondrial electron transport is an enzymatic source of oxygen radical generation and also a target of oxidant-induced damage. Chronic increases in oxygen radical production in the mitochondria can lead to a catastrophic cycle of mitochondrial DNA (mtDNA) damage as well as functional decline, further oxygen radical generation, and cellular injury. Reactive oxygen species induce myocyte hypertrophy, apoptosis, and interstitial fibrosis by activating matrix metalloproteinases. These cellular events play an important role in the development and progression of maladaptive cardiac remodeling and failure. Therefore, mitochondrial oxidative stress and mtDNA damage are good therapeutic targets. Overexpression of mitochondrial transcription factor A (TFAM) could ameliorate the decline in mtDNA copy number and preserve it at a normal level in failing hearts. Consistent with alterations in mtDNA, the decrease in oxidative capacities was also prevented. Therefore, the activation of TFAM expression could ameliorate the pathophysiologic processes seen in myocardial failure. Inhibition of mitochondrial oxidative stress and mtDNA damage could be novel and potentially very effective treatment strategies for heart failure.

Mitochondrial Oxidative Stress and Heart Failure

Recent experimental and clinical studies have suggested that oxidative stress is enhanced in heart failure. Chronic increases in oxygen radical production in the mitochondria can lead to a catastrophic cycle of mitochondrial DNA (mtDNA) damage as well as functional decline, further oxygen radical generation, and cellular injury. Reactive oxygen species induce myocyte hypertrophy, apoptosis, and interstitial fibrosis by activating matrix metalloproteinases. These cellular events play an important role in the development and progression of maladaptive cardiac remodeling and failure. Overexpression of mitochondrial transcription factor A (TFAM) could ameliorate the decline in mtDNA copy number and preserve it at a normal level in failing hearts. Consistent with alterations in mtDNA, the decrease in oxidative capacities was also prevented. Therefore, the activation of TFAM expression could ameliorate the pathophysiological processes seen in myocardial failure. Inhibition of mitochondrial oxidative stress and DNA damage could be the most effective and novel treatment strategies for heart failure.