Sexual dimorphism in the effect of maternal obesity on antioxidant defense mechanisms in the human placenta

IntroductionMaternal obesity creates an adverse intrauterine environment, negatively impacts placental respiration, is associated with a higher incidence of pregnancy complications and programs the offspring for disease in adult life in a sexually dimorphic manner. We defined the effect of maternal obesity and fetal sex on pro- and anti-oxidant status in placenta and placental mitochondria. Methods: Placental villous tissue was collected at term via c-section prior to labor from four groups of patients based on fetal sex and prepregnancy/1st trimester body mass index: lean - BMI 22.1 ± 0.3 (6 male, 6 female) and obese - BMI 36.3 ± 0.4 (6 male, 6 female). Antioxidant enzyme activity, mitochondrial protein carbonyls, nitrotyrosine residues, total and nitrated superoxide dismutase (SOD) and nitric oxide synthesis were measured. Results: Maternal obesity was associated with decreased SOD and catalase activity, and total antioxidant capacity (TAC), but increased oxidative (protein carbonyls) and nitrative (nitrotyrosine) stress in a sexually dimorphic manner. Placentas of lean women with a male fetus had higher SOD activity and TAC (p < 0.05) than other groups whereas obese women with a male fetus had highest carbonyls and nitrotyrosine (p < 0.05). Glutathione peroxidase and thioredoxin reductase activity increased with obesity, significantly with a male fetus, perhaps as a compensatory response. Conclusion: Maternal obesity affects oxidative stress and antioxidant activity in the placenta in a sexually dimorphic manner. The male fetus of a lean women has the highest antioxidant activity, a protection which is lost with obesity perhaps contributing to the increased incidence of adverse outcomes with a male fetus.     

Nitric oxide and calcium together inactivate mitochondrial complex I and induce cytochrome c release

Cellular nitric oxide (NO) and calcium levels have been reported to increase during various pathologies, including particularly ischaemia. In this study, we investigated whether elevated NO and calcium levels can synergistically damage isolated rat heart mitochondria. We found that NO and calcium together inhibited the oxygen consumption of mitochondria respiring on pyruvate + malate, but not mitochondria respiring on succinate. In the same conditions, complex I activity was synergistically inhibited by NO and calcium, and this inhibition was completely prevented by superoxide dismutase or urate, suggesting that the inhibition was mediated by peroxynitrite. Indeed, we found NO and calcium-stimulated mitochondrial production of peroxynitrite. The inhibition of complex I activity by NO and calcium was reversed by reduced thiols or light (as was complex I inhibition by S-nitrosothiols or peroxynitrite) suggesting that the inhibition may involve S-nitrosation or Fe-nitrosylation of complex I. However, NO and calcium also caused loss of mitochondrial cytochrome c, and the induced inhibition of respiration was partially reversed by addition of exogenous cytochrome c. Thus, NO and calcium appear to synergistically inhibit mitochondrial respiration, partly by inactivation of complex I and partly by inducing cytochrome c release.     

电针对老年性痴呆模型大鼠海马线粒体酶活性的影响

目的研究电针对老年性痴呆（AD）模型大鼠海码神经元线粒体酶活性的影响，从能量代谢的角度探讨电针治疗AD的部分作用机制。方法以D-半乳糖腹腔注射和Aβ1-40海马注射诱导形成的AD模型大鼠为研究对象，电针“百会”、“涌泉”穴，每日1次，连续20d。以通道式水迷宫测试学习记忆能力的变化，评价电针对AD的治疗效庸；以生化方法检测海马神经元线粒体琥珀酸脱氢酶、Na^＋ -K^＋ -ATP酶、Ca^2＋ -Mg^2＋ -ATP酶的活性。结果电针能有效改善AD模型大鼠学习记忆能力，提高线粒体琥珀酸脱氢酶、Na^＋ -K^＋ -ATP酶、Ca^2＋ -Mg^2＋ -ATP酶活性。结论电针可促进ATP的合成与分解利用，调节线粒体功能，改善AD能量代谢障碍。     

REM-PCL对犬缺血再灌注心肌线粒体抗氧化能力的影响

目的：观察REM-PCL对体外循环（CPB）中犬心肌线粒体抗氧化能力的影响。方法：采用CPB心肌缺血再灌注模型,12只犬随机分为REM-PCL组（RP组,n=6）和对照组（C组,n=6）。RP组和C组分别于CPB前静脉注射0.2 mg/kg REM-PCL及等量生理盐水。两组分别于转机前、缺血60 min、再灌注30 min和60 min时,检测总抗氧化能力（T-AOC）、谷胱甘肽过氧化物酶（GSH-PX）、丙二醛（MDA）、超氧化物歧化酶（SOD）和心肌线粒体线粒体肿胀度（MSD）。结果：与转机前比较,两组缺血后T-AOC、GSH-PX及SOD均降低,MDA和MSD含量均升高（P<0.01）;再灌注后C组T-AOC、GSH-PX及SOD均降低（P<0.01）,MDA和MSD含量均升高（P<0.01）;再灌注60 min时RP组T-AOC、MDA、MSD、GSH-PX及SOD与转机前比较差异无统计学意义（P>0.05）。缺血60 min和再灌注后RP组MDA和MSD含量均显著低于C组（P<0.01）,T-AOC、GSH-PX及SOD均显著高于C组（P<0.01）。结论：REM-PCL预处理可通过提高CPB中心肌线粒体抗氧化能力来减轻心肌线粒体损伤。     

The Potential Application of Mitochondrial Medicine in Toxicologic Poisoning

The advancement of biomolecular techniques has continued to advance in the area of mitochondrial medicine. This has allowed clinicians and researchers to more effectively study the bioenergetics of the mitochondria in various disease states. One potential technique in mitochondrial medicine is the generation of cytoplasmic hybrids. A cytoplasmic hybrid or cybrid are created by introducing mitochondrial DNA (mtDNA) of interest into cells depleted of mtDNA. A cybrid is therefore a hybrid cell that mixes the nuclear genome from one cell with the mitochondrial genes from another cell. Cybrids are currently utilized in mitochondrial research to demonstrate mitochondrial involvement in a wide range of diseases that include diabetes, Parkinson’s disease and inherited diseases. At this time the use of cybrids to study toxicologic poisoning is limited and offers a potential avenue of research in this area.     

母体肢体缺血预处理对宫内窘迫胎鼠复氧后海马神经元线粒体结构和功能的影响

目的:探索母体肢体缺血预处理(LIP)对宫内窘迫胎鼠复氧后海马神经元线粒体结构和功能的影响。方法:将孕20 d的40只SD大鼠随机分为假手术组(S组)、LIP对照组、胎鼠宫内窘迫组(FD组)和LIP+FD组。通过实验设计建立胎鼠宫内窘迫模型,观察各组胎鼠海马CA1区线粒体超微结构的变化;检测海马线粒体跨膜电位变化;测定海马组织活性氧簇(ROS)、三磷酸腺苷(ATP)、丙二醛(MDA)含量及锰-超氧化物歧化酶(MnSOD)活性变化。结果:(1)与S组比较,FD组和LIP+FD组电镜下观察胎鼠海马CA1区线粒体呈不同程度破坏,线粒体膜电位下降,ATP含量和Mn-SOD活性降低,ROS和MDA含量增加(P0.05)。(2)与FD组比较,LIP+FD组胎鼠海马CA1区线粒体的超微结构保持较好的完整性,线粒体膜电位明显提高,海马ATP含量和Mn-SOD活性显著增高,ROS和MDA含量减少(P0.05)。结论:母体肢体缺血预处理对宫内窘迫胎鼠复氧后海马神经元线粒体功能具有保护作用。     

吡那地尔后处理大鼠缺血再灌注损伤心肌线粒体的蛋白质组学研究

 目的: 运用蛋白质组学研究方法探讨吡那地尔后处理对缺血再灌注损伤大鼠心肌的保护作用。方法: 建立Langendorff大鼠离体心脏缺血再灌注损伤模型,随机分为吡那地尔后处理组(Pina组)和缺血再灌注损伤组(I/R组),每组9只。提取心肌线粒体蛋白质行双向凝胶电泳,应用质谱鉴定差异大于2倍的蛋白质点。结果: Pina组与I/R组比较,共发现7个差异蛋白质:Pina组NADH脱氢酶1α亚复合体10亚基(NDUFA10)﹑NADH脱氢酶铁硫蛋白2(NDUFS2)和NADH脱氢酶黄素蛋白2(NDUFV2)表达低于I/R组;Pina组异柠檬酸脱氢酶α亚基(IDHA)和Δ^3,5-Δ^2,4-二烯酰辅酶A异构酶(ECH1)表达高于I/R组;另有2个蛋白质点均被鉴定为ATP合酶δ亚基,一个蛋白质点表达升高,而另一个表达降低。结论:吡那地尔后处理可能抑制了复合体Ⅰ的亚基(NDUFA10﹑NDUFS2和NDUFV2)代偿性增加,但促进了IDHA和ECH1表达并引发了ATP合酶δ亚基发生磷酸化,这些改变可能均与吡那地尔后处理保护心肌的作用有关。     

Epigenetic dimension of oxygen radical injury in spermatogonial epithelial cells

The present work reports a direct role of mitochondrial oxidative stress induced aberrant chromatin regulation, as a central phenomenon, to perturbed genomic integrity in the testicular milieu. Oxygen-radical injury following N-succinimidyl N-methylcarbamate treatment in mouse spermatogonial epithelial (GC-1 spg) cells induced functional derailment of mitochondrial machinery. Mitophagy resulted in marked inhibition of mitochondrial respiration and reduced mtDNA copy number. Impaired cell cycle progression along with altered H3K9me1, H4K20me3, H3, AcH3 and uH2A histone modifications were observed in the treated cells. Dense heterochromatin foci and aberrant expression of HP1α in nuclei of treated cells implied onset of senescence associated secretory phenotype mediated through nuclear accumulation of NF-κB. Neoplastic nature of daughter clones, emerged from senescent mother phenotypes was confirmed by cytogenetic instability, aberrant let-7a and let-7b miRNA expression and anchorage independent growth. Together, our results provide the first insights of redox-dependent epigenomic imbalance in spermatogonia, a previously unknown molecular paradigm.     

Calcium,mitochondria and the initiation of acute pancreatitis

Acute pancreatitis is characterized by necrosis of its parenchymal cells and influx and activation of inflammatory cells that further promote injury and necrosis. This review is intended to discuss the central role of disorders of calcium metabolism and mitochondrial dysfunction in the mechanism of pancreatitis development. The disorders are placed in context of calcium and mitochondria in physiologic function of the pancreas. Moreover, we discuss potential therapeutics for preventing pathologic calcium signals that injure mitochondria and interventions that promote the removal of injured mitochondria and regenerate new and heathy populations of mitochondria.     

Recycle or die: the role of autophagy in cardioprotection

Autophagy is a highly conserved cellular process responsible for the degradation of long-lived proteins and organelles. Autophagy occurs at low levels under normal conditions, but is upregulated in response to stress such as nutrient deprivation, hypoxia, mitochondrial dysfunction, and infection. Upregulation of autophagy may be beneficial to the cell by recycling of proteins to generate free amino acids and fatty acids needed to maintain energy production, by removing damaged organelles, and by preventing accumulation of protein aggregates. In contrast, there is evidence that enhanced autophagy can contribute to cell death, possibly through excessive self-digestion. In the heart, autophagy has an essential role for maintaining cellular homeostasis under normal conditions and increased autophagy can be seen in conditions of starvation, ischemia/reperfusion, and heart failure. However, the functional significance of autophagy in heart disease is unclear and controversial. Here, we review the literature and discuss the evidence that autophagy can have both beneficial and detrimental roles in the myocardium depending on the level of autophagy, and discuss potential mechanisms by which autophagy provides protection in cells.