Embryo development is impaired by sperm mitochondrial-derived ROS

BACKGROUND: Basal energetic metabolism in sperm, particularly oxidative phosphorylation, is known to condition not only their oocyte fertilising ability, but also the subsequent embryo development. While the molecular pathways underlying these events still need to be elucidated, reactive oxygen species (ROS) could have a relevant role. We, therefore, aimed to describe the mechanisms through which mitochondrial activity can influence the first stages of embryo development. RESULTS: We first show that embryo development is tightly influenced by both intracellular ROS and mitochondrial activity. In addition, we depict that the inhibition of mitochondrial activity dramatically decreases intracellular ROS levels. Finally, we also demonstrate that the inhibition of mitochondrial respiration positively influences sperm DNA integrity, most likely because of the depletion of intracellular ROS formation. CONCLUSION: Collectively, the data presented in this work reveals that impairment of early embryo development may result from the accumulation of sperm DNA damage caused by mitochondrial-derived ROS.

The effects of aerobic exercise on myocardial energy metabolism and mitochondrial respiration after myocardial infarction / 中华物理医学与康复杂志

Objective:To explore any effect of aerobic exercise on cardiac energy metabolism and mitochondrial respiration after myocardial infarction.Methods:Forty-five Sprague-Dawley rats were randomly divided into a sham operation group, a heart failure control group and a heart failure exercise group. Myocardial infarction was induced in the heart failure groups using coronary artery ligation. Four weeks after the successful modeling, the heart failure exercise group underwent 8 weeks of aerobic treadmill exercise. The cardiac function and exercise ability of all of the rats were then observed using echocardiography and the incremental treadmill exercise test. Myocardial creatine phosphate (PCr) and adenosine triphosphate (ATP) were measured by magnetic resonance spectroscopy, and the respiratory function of the myocardial mitochondria was evaluated by using cell respirometry.Results:Compared with the sham operation group, the average PCr content, PCr/ATP ratio, oxygen consumption of mitochondrial respiratory chain complexes I and II, left ventricular shortening fraction (FS) and ejection fraction (EF), maximum running speed, exhaustion distance and exhaustion time in the incremental treadmill exercise test were all significantly worse in the heart failure control group. Moreover, the average ATP content, complex I oxygen consumption, left ventricular FS and EF, and the maximum running speed, exhaustion distance and exhaustion time in incremental treadmill exercise of the heart failure exercise group were all superior to those of the heart failure control group.However, no significant differences were observed in the average PCr/ATP ratio between the heart failure exercise and control groups.Conclusions:Regular aerobic exercise can improve cardiac performance after chronic heart failure, at least in rats. The mechanism may be related to increased levels of myocardial ATP and better mitochondrial complex I functioning. The PCr/ATP ratio may not be a suitable biomarker for evaluating the benefits of exercise for the heart.

Allergens of the urushiol family promote mitochondrial dysfunction by inhibiting the electron transport at the level of cytochromes b and chemically modify cytochrome c1

BACKGROUND: Urushiols are pro-electrophilic haptens that cause severe contact dermatitis mediated by CD8+ effector T-cells and downregulated by CD4+ T-cells. However, the molecular mechanism by which urushiols stimulate innate immunity in the initial stages of this allergic reaction is poorly understood. Here we explore the sub-cellular mechanisms by which urushiols initiate the allergic response. RESULTS: Electron microscopy observations of mouse ears exposed to litreol (3-n-pentadecyl-10-enyl-catechol]) showed keratinocytes containing swollen mitochondria with round electron-dense inclusion bodies in the matrix. Biochemical analyses of sub-mitochondrial fractions revealed an inhibitory effect of urushiols on electron flow through the mitochondrial respiratory chain, which requires both the aliphatic and catecholic moieties of these allergens. Moreover, urushiols extracted from poison ivy/oak (mixtures of 3-n-pentadecyl-8,11,13 enyl/3-n-heptadecyl-8,11 enyl catechol) exerted a higher inhibitory effect on mitochondrial respiration than did pentadecyl catechol or litreol, indicating that the higher number of unsaturations in the aliphatic chain, stronger the allergenicity of urushiols. Furthermore, the analysis of radioactive proteins isolated from mitochondria incubated with 3H-litreol, indicated that this urushiol was bound to cytochrome c1. According to the proximity of cytochromes c1 and b, functional evidence indicated the site of electron flow inhibition was within complex III, in between cytochromes bL (cyt b566) and bH (cyt b562). CONCLUSION: Our data provide functional and molecular evidence indicating that the interruption of the mitochondrial electron transport chain constitutes an important mechanism by which urushiols initiates the allergic response. Thus, mitochondria may constitute a source of cellular targets for generating neoantigens involved in the T-cell mediated allergy induced by urushiols.

Lidocaine inhibits the malignant proliferation, invasion and regulates the mitochondrial respiration of osteosarcoma MG-63 cells / 中国临床药理学与治疗学

AIM: To investigate the effects of lidocaine on malignant proliferation, invasion and mitochondrial respiration of osteosarcoma MG-63 cells. METHODS: MG-63 cells were treated with 25, 50 and 100 μmol/L of lidocaine and were randomly divided into four groups: lidocaine 0 μmol/L, lidocaine 25 μmol/L, lidocaine 50 μmol/L and lidocaine 100 μmol/L for subsequent experiments. BrdU staining was used to detect cell proliferation. Transwell for cell invasion. Protein expression levels of Ki67, Survivin, VEGF and Vimentin were detected by Western blot. Mitochondrial membrane potential was detected by flow separator. Activity of mitochondrial respiratory complex was detected by Clark oxygen electrode method. The kit detected the content of ATP, SOD and MDA.RESULTS: Results showed that compared with lidocaine 0 μmol/L group, BrdU positive cells in lidocaine 50, 100 μmol/L group was significantly reduced (P<0.05), invasive cells was significantly reduced (P<0.05), Ki67, Survivin, VEGF, Vimentin protein levels decreased significantly (P<0.05), mitochondrial membrane potential decreased significantly, compound I, II, IV activity decreased significantly (P<0.05), ATP, SOD content decreased significantly (P<0.05), MDA content was significantly increased (P<0.05). CONCLUSION: Lidocaine can inhibit the malignant proliferation, invasion and improve the mitochondrial function of osteosarcoma MG-63 cells.

Effects of carbon monoxide releasing molecule-2 on post-resuscitation myocardial dysfunction / 中华急诊医学杂志

Objective To investigate the protective role of carbon monoxide releasing molecule-2 (CORM-2) in post-resuscitation myocardial dysfunction (PRMD) in rat models of cardiopulmonary resuscitation (CPR).Methods Cardiopulmonary resuscitation model was established after cardiac arrest induced by ventricular fibrillation.Male healthy Sprague-Dawley (SD) rats were randomly (random number) divided into 4 groups according to random number table:control group,CORM-2 group,inactive CORM-2 (iCORM-2) group and Sham group,in which the equal volume (1 mL) of 0.2％ DMSO,50 μmol/kg CORM-2,50 μmol/kg iCORM-2 and 0.2％ DMSO were respectively administered into the rats of these groups after resuscitation.The ejection fraction (EF) of left ventricle and myocardial performance index (MPI) were measured to detect the myocardial function by echocardiography at 12 hours after resuscitation.Mitochondrial respiration was assessed with Clark oxygen electrode at the same time.Western blot was used to determine the ratio of mitochondrial cytochrome c (cyt c) to cytoplasmic cyt c as well as caspase-3 level.Multiple comparisons were made by analysis of variance.Results Compared with the control group,higher EF and MPI,higher state Ⅲ respiration rate and respiratory control rate (RCR) of mitochondria,and decreased ratio of mitochondrial cytc/cytoplasmic cyt c and lower caspase-3 level were observed in the CORM-2 group (P ＜ 0.05).However,there were no significant differences in above biomarkers found between iCORM-2 group and control group (P ＞ 0.05).Conclusions The CO released from CORM-2 might improve mitochondrial respiration and PRMD by inhibition of myocardial apoptosis via a mitochondrial pathway.

Role of platelet-derived growth factor after hemorrhagic shock in rats / 局解手术学杂志

Objective To investigate platelet-derived growth factor ( PDGF ) protection on blood flow and mitochondrial function of hemorrhagic shock rats. Methods Ninety-six SD rats were randomly divided into six groups including shock group, lactated ringer's solution (LR) resuscitation group,PDGF treatment groups(1,3. 5,7,15μg/kg). Laster-Doppler and oxygen concentration determination method were applied to observe the protective effect of PDGF treatment on animal survival,blood flow and mitochondrial function in liver and kidney. Re-sults As compared with LR resuscitation group,PDGF treatment increased animal survival rate and also improved blood fiow of liver and kindy,mitochondrial respiration control ration(RCR),of which the group with 3. 5μg/kg had the best result. Conclusion This finding sug-gests that PDGF may be a potential agent to treat acute critical such as hemorrhagic shock.

MicroRNA let-7f mediates mitochondrial respiratory deficit induced by repeated ethanol exposure and withdrawal in HT22 cells.

Aims: The expression of gene and gene product is typically inhibited by a small noncoding RNA (microRNA) or DNA methylation. The aim of this study is to investigate mechanisms involving microRNA let-7f by which the repeated cycles of ethanol exposure and withdrawal provoke mitochondrial respiratory damage. Study Design: The rat or cell model of repeated withdrawal from a high dose of ethanol exposure was used to mimic human alcoholics who repeat the cycles of heavy drinking and unsuccessful attempts at abstaining. Place and Duration of Study: Department of Pharmacology and Neuroscience University of North Texas Health Science Center at Fort Worth, between June 2011 and March 2014. Methodology: Male adult rats received an ethanol program, consisting of two cycles of ethanol exposure (4 weeks) and withdrawal (2 weeks). At the end of the ethanol program, one hemisphere of each rat was used to measure the level of let-7f using TaqMan let-7f primers and qPCR. The other hemisphere was used to measure the methylation of cytosine in let-7f gene using bisulfite conversion and pyrosequencing. Separately, HT22 cells (mouse hippocampal cells) were exposed to an ethanol program, consisting of two cycles of ethanol exposure (20 hours) and withdrawal (4 hours). During the entire ethanol program, the cells were treated with let-7f antagomir (inhibitor) or a methylation-inducing methyl-donor. The role of let-7f in mitochondria was assessed by quantifying a mitochondrial enzyme, cytochrome c oxidase-IV (COX subunit IV) and realtime mitochondrial respiration using an immunoblot method and XF respirometry, respectively. Results: The level of let-7f increased (2.4±0.5 fold increase), whereas the methylation of let-7f gene decreased in the brain of rats that underwent repeated ethanol exposure and withdrawal (called “repeated-ethanol/withdrawal”). The methyl-donor treatment completely abolished the increase in let-7f induced by repeated-ethanol/withdrawal. let-7f antagomir treatment also abolished the inhibiting effect of repeated-ethanol/withdrawal on COX-IV and mitochondrial respiration. Conclusion: These data suggest that repeated-ethanol/withdrawal provokes the dysregulation of let-7f, thereby damaging brain mitochondria. Mitochondria-associated microRNA may be a potential research and drug target to manage alcoholism.

Plant growth inhibitory activity of N, N´-di-(4-R-phenyl)-alkanediamides / Actividad inhibitoria de crecimiento de plantas de N, N’-di-(4-R-phenyl)-alcanodiamidas

Diamides are a class of metabolites that occurring in some Meliaceae plants, in Aglaia spp for example, with an ample body of biological activities, being insecticidal and herbicidal two of the most important. In our program of search for botanical pesticides, a series of N,N´-di-(4-R-phenyl)-alkanediamides was evaluated for its herbicidal activity. Many of the analogues tested exhibited moderate to good herbicidal activity both pre-emergence and post-emergence and have been found to inhibit energetic metabolism of pre-emergence weeds. The structure-activity relationships were probed by substitution on the benzene ring. Among the variations investigated, it was found that maximal herbicidal activity was obtained by substitution of –F, -CN and -Br at the aromatic portion and by n=2 of the aliphatic long chain. This last number of carbons (n=2) substitution was the key for the inhibitory activity.

Diamidas son una clase de metabolitos que estan presentes en plantas perteneciente a la familia de la Meliaceas, en Aglaia por ejemplo, poseen un amplio cuerpo de actividades biologicas, siendo la insecticida y la herbicida dos de las mas importantes. En nuestro programa para la busqueda de pesticidas botanicos, una serie de N,N’-di-(4-R-phenyl)-alkanodiamidas se evaluo para su actividad herbicida. Muchos de los analogos exhibieron desde buenas a moderadas actividades, tanto como pre-emergentes como post-emergentes y ademas se encontro que inhiben el metabolismo pre-emergente energetico de malezas. La relacion estructura-actividad fue probada por sustitución sobre al anillo aromatico. Entre las variaciones investigadas, se encontro que la maxima actividad herbicida se obtuvo por sustitución de F, CN y Br en la porcion aromatica y por n=2 del largo de la cadena alifatica. Este ultimo numero de carbonos de sustitución (n=2) fue clave para la actividad inhibitoria.

Catechol inhibits FADH2-linked respiration in rat liver mitochondrial fraction

PURPOSE: The aim of this work was to investigate the hypothesis that catechol inhibits FADH2-linked basal respiration in mitochondria isolated from rat liver homogenates. Moreover, catechol ability to induce peroxidation of biomolecules in liver nuclear fractions was also studied. METHODS: Rat liver homogenates were incubated with 1mM 1,2-dihydroxybenzene (catechol) at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate. Nuclear fractions were incubated in the presence of 1 mM catechol for 17 hours at room temperature and the peroxidation of biomolecules was investigated by the reaction with thiobarbituric acid, which was determined spectrophotometrically at 535 nm. RESULTS: Catechol induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration, however this substance was unable to induce a direct peroxidation of biomolecules in hepatic nuclear fractions. CONCLUSION: Catechol produced an inhibition of basal respiration associated to FADH2 in isolated liver mitochondria that could lead to cytotoxicity, ROS generation and cell death.

OBJETIVO: Testar a hipótese do catecol inibir a respiração basal associada ao FADH2 em frações mitocondriais hepáticas de rato. Além disso, estudou-se também a capacidade do catecol de induzir peroxidação de biomoléculas nas frações nucleares. MÉTODOS: Os homogeneizados de fígado de ratos foram incubados com catecol a 1 mM em pH fisiológico. Depois disso, as frações mitocondriais foram isoladas por centrifugação diferencial. O consumo basal de oxigênio foi medido com um eletrodo do tipo Clark após injeção de succinato a 10 mM. Frações nucleares foram incubadas com catecol por 17 horas à temperatura ambiente e a peroxidação de biomoléculas foi investigada pela reação com o ácido tiobarbitúrico e mensurada espectrofotometricamente. RESULTADOS: O catecol induziu uma inibição parcial da respiração basal mitocondrial associada ao FADH2 de forma dependente do tempo, contudo essa substância não induziu peroxidação direta das biomoléculas presentes nas frações nucleares hepáticas. CONCLUSÃO: O catecol produz inibição da respiração basal associada ao FADH2 em mitocôndrias isoladas de fígado, o que pode levar à toxicidade, produção de espécies reativas e morte celular.

The opening of neuronal mitochondria permeability transition pore affects respiratory function during thrombotic cerebral ischemia in tree shrews / 中国病理生理杂志

AIM: The present study explored those changes in brain mitochondrial respiration in different times after thrombotic cerebral ischemia induced by photochemical reaction in primate's animal tree shrew and o bserved the effects of platelet-activating factor (PAF) receptor antagonist gin kgolide B (GB) and immunosuppressor cyclosporin A (CsA) on neuronal mitochondria l respiration and mitochondrial permeability transition pore(MPT) in twenty-four hours after occlusion and showed their neuronprotective mechanism and expatiate the relationship between mitochondrial respiration and MPT. METHODS: The focal thrombotic cerebral ischemia was formed by photochemistry-induce d technology in tree shrews. At 4,24,72 h after focal cerebral ischemia, the n euronal mitochondria were centrifuged. Clark oxygen electrode was used to measur e the changes in neuronal mitochondrial respiration.Pretreatment for experiment al animals with GB and CsA at 6h after occlusion, we centrifuged the mitochondri a and measured the changes in neuronal mitochondrial respiration at 24 h after o cclusion. In addition, experiments were performed in a flurometer by measuring CaCl 2 100 ?mol/L induced centrifuged mitochondrial swelling and GB or CsA were added at the same time. RESULTS: All of respiration state Ⅲ, RCR and P/O decreased after cerebral ischemia. There were significant difference s between every ischemic group and sham, especially at 24 h (P