Molecular mechanisms and cellular events involved in the neuroprotective actions of estradiol. Analysis of sex differences

Estradiol, either from peripheral or central origin, activates multiple molecular neuroprotective and neuroreparative responses that, being mediated by estrogen receptors or by estrogen receptor independent mechanisms, are initiated at the membrane, the cytoplasm or the cell nucleus of neural cells. Estrogen-dependent signaling regulates a variety of cellular events, such as intracellular Ca²⁺ levels, mitochondrial respiratory capacity, ATP production, mitochondrial membrane potential, autophagy and apoptosis. In turn, these molecular and cellular actions of estradiol are integrated by neurons and non-neuronal cells to generate different tissue protective responses, decreasing blood-brain barrier permeability, oxidative stress, neuroinflammation and excitotoxicity and promoting synaptic plasticity, axonal growth, neurogenesis, remyelination and neuroregeneration. Recent findings indicate that the neuroprotective and neuroreparative actions of estradiol are different in males and females and further research is necessary to fully elucidate the causes for this sex difference.     

Neurotoxicity assessment of triazole fungicides on mitochondrial oxidative respiration and lipids in differentiated human SH-SY5Y neuroblastoma cells

Indiscriminate overuse or occupational exposure to agricultural chemicals can lead to neurotoxicity. Many pesticides act to impair mitochondrial function which can lead to exacerbation of neurodegeneration. Triazole fungicides are applied to grain, fruit, and vegetable crops to combat mold and fungi and their use is increasing worldwide. Here, we assessed the in vitro toxicity of two widely used triazole fungicides, propiconazole and tebuconazole, to mitochondria using differentiated SH-SY5Y neuroblastoma cells as an in vitro cell model used in Parkinson’s disease research. Cell viability (based on ATP levels), mitochondrial membrane potential, oxidative respiration, and reactive oxygen species (ROS) were measured following fungicide treatments. Cell viability was decreased with 100 μM propiconazole after 24 and 48 h, while tebuconazole required higher doses to affect viability (−200 μM at 24 h). Mitochondrial membrane potential (MMP) was reduced with 50 μM propiconazole after 24 h while 200 μM tebuconazole reduced MMP. Oxidative respiration of SH-SY5Y cells was then measured using a XFe24 Flux analyzer and 100 μM propiconazole reduced basal respiration, oligomycin-induced ATP production, and FCCP-induced maximum respiration by −40−50%, while tebuconazole did not affect mitochondrial bioenergetics at the concentrations tested. Acute exposure to 100 μM propiconazole over 4 h did not immediately affect oxidative respiration in SH-SY5Y cells. ROS were not induced by propiconazole and tebuconazole up to 100 and 300 μM respectively. Based on these results, we focused our lipidomics investigations on SH-SY5Y exposed only to propiconazole, as lipid dysregulation is associated with mitochondrial dysfunction. Both 50 and 100 μM propiconazole altered the abundance of some ceramides, specifically reducing glucosylceramide non-hydroxyfatty acid-sphingosine (HexCer-NS) and increasing N-stearoyl-phytosphingosine (CerNP). Moreover, a recently discovered bioactive lipid called fatty acid ester of hydroxy fatty acid (FAHFA) was increased 5-fold, hypothesized to be a neuroprotective mechanism that has been demonstrated in other studies of human diseases. Additional lipids reduced in abundance included oxidized phosphatidylcholine (OxPC) and oxidized phosphatidylethanolamine (OxPE). There were no changes in cellular triacylglycerols nor total lipids with exposure to propiconazole. Taken together, this study provides insight into the toxicity of triazole fungicides in neuronal cells, which has implications for neurodegenerative diseases that involve the mitochondria such as Parkinson’s disease.     

Role of cell-free DNA for predicting incidence and outcome of patients with ischemic stroke

Early diagnosis and prognosis of ischemic stroke remains a critical challenge in clinical settings. A blood biomarker can be a promising quantitative tool to represent the clinical manifestations in ischemic stroke. Cell-free DNA (cfDNA) has recently turned out to be a popular circulating biomarker due to its potential relevance for diagnostic applications in a variety of disorders. Despite bright outlook of cfDNA in clinical applications, very less is known about its origin, composition, or function. Several recent studies have identified cell-derived mitochondrial components including mitochondrial DNA (mtDNA) in the extracellular spaces including blood and cerebrospinal fluid. However, the time course of alterations in plasma mtDNA concentrations in patients after an ischemic stroke is poorly understood. DNA is thought to be freed into the plasma shortly after the commencement of an ischemic stroke and then gradually decreased. However, the importance of cell-free mtDNA (cf-mtDNA) in ischemic stroke is still unknown. This review summarizes about the utility of biomarkers which has been standardized in clinical settings and role of cfDNA including cf-mtDNA as a non-invasive potential biomarker of ischemic stroke.     

短时间高氧对肺泡Ⅱ型上皮细胞线粒体活性氧产生及相关通路的影响

目的探讨短时间高氧对肺泡Ⅱ型上皮细胞（AECⅡ）线粒体Ca²⁺ /烟酰胺腺嘌呤二核苷酸（NAD⁺）/沉默信息调节因子3（SIRT3）/超氧化物歧化酶2（SOD2）通路及活性氧的影响。 方法将RLE-6TN细胞株细胞分为对照组、高氧组及线粒体钙通道拮抗剂组（拮抗剂组）。对照组细胞置于常规细胞培养箱中，高氧组细胞置于氧浓度为90%的培养箱中，拮抗剂组细胞加入钌红（2 μmol / L）后置于氧浓度为90%的培养箱中，各组均持续培养4 h。随后，对各组细胞线粒体内Ca²⁺、活性氧、NAD⁺、还原型烟酰胺腺嘌呤二核苷酸（NADH）含量进行检测，并计算NAD⁺ / NADH比值；同时，采用实时荧光定量PCR检测SIRT3和SOD2信使RNA（mRNA）水平。 结果各组间细胞线粒体内Ca²⁺、活性氧、NAD⁺、NADH、NAD⁺ / NADH比值及SIRT3 mRNA、SOD2 mRNA表达水平的比较，差异均有统计学意义（F = 183.500、135.900、32.140、51.520、128.300、59.970、45.020，P均< 0.001）。且与对照组及拮抗剂组比较，高氧组细胞线粒体内Ca²⁺[（19.5 ± 0.8）、（17.2 ± 0.7）、（24.3 ± 0.3）nmol / L]、活性氧[（491 ± 9）、（480 ± 5）、（530 ± 6）相对荧光单位]及NADH[（0.85 ± 0.03）、（0.87 ± 0.04）、（1.06 ± 0.06）nmol / 10⁴ cells]含量均明显升高，而NAD⁺含量[（3.30 ± 0.12）、（3.24 ± 0.14）、（2.58 ± 0.29）nmol / 10⁴ cells]、NAD⁺ / NADH比值[（3.89 ± 0.15）、（3.71 ± 0.15）、（2.44 ± 0.27）]、SIRT3 mRNA[（1.01 ± 0.11）、（0.96 ± 0.08）、（0.45 ± 0.09）]及SOD2 mRNA[（1.01 ± 0.14）、（1.05 ± 0.11）、（0.48 ± 0.10）]表达水平均显著降低（P均< 0.05）。 结论短时间高氧可通过AECⅡ线粒体内Ca²⁺ / NAD⁺ / SIRT3 / SOD2通路导致活性氧蓄积。     

Mitochondria in the signaling pathways that control longevity and health span

Genetic and pharmacological intervention studies have identified evolutionarily conserved and functionally interconnected networks of cellular energy homeostasis, nutrient-sensing, and genome damage response signaling pathways, as prominent regulators of longevity and health span in various species. Mitochondria are the primary sites of ATP production and are key players in several other important cellular processes. Mitochondrial dysfunction diminishes tissue and organ functional performance and is a commonly considered feature of the aging process. Here we review the evidence that through reciprocal and multilevel functional interactions, mitochondria are implicated in the lifespan modulation function of these pathways, which altogether constitute a highly dynamic and complex system that controls the aging process. An important characteristic of these pathways is their extensive crosstalk and apparent malleability to modification by non-invasive pharmacological, dietary, and lifestyle interventions, with promising effects on lifespan and health span in animal models and potentially also in humans.     

Combinatory antitumor therapy by cascade targeting of a single drug

Combination therapy has shown its promise in the clinic for enhancing the efficacy of tumor treatment. However, the dose control of multiple drugs and their non-overlapping toxicity from different drugs are still great challenge. In this work, a single model drug, paclitaxel (PTX), is used to realize combination therapy and solve the problems mentioned above. Either PTX or its triphenylphosphine derivative (TPTX) is encapsulated in galactose-modified liposomes (GLips) to obtain GLips-P or GLips-TP, which are simply mixed in different ratios to finely control the proportion of PTX and TPTX. These mixed liposomes, GLips-P/TP, feature a cascade target delivery of PTX, from tissue to cell, and then to organelle. PTX plays a primary role to cause the cytotoxicity by microtubule bindings in cytoplasm, while TPTX is proved to increase the intracellular levels of caspase-3 and caspase-9 that cause apoptosis via a mitochondria-mediated pathway. Notably, GLips-P/TP 3:1 exhibited the significant drug synergy in both cytotoxicity assay of HepG2 cells and the treatment efficacy in Heps xenograft ICR mouse models. This work not only demonstrates the great promise of a cascade targeting delivery for precise tumor treatment, but also offers a novel platform to design combinatory therapy systems using a single drug.     

Mitochondrial dysfunction from malathion and chlorpyrifos exposure is associated with degeneration of GABAergic neurons in Caenorhabditis elegans

Toxicity resulting from off-target effects, beyond acetylcholine esterase inhibition, for the commonly used organophosphate (OP) insecticides chlorpyrifos (CPS) and malathion (MA) was investigated using Saccharomyces cerevisiae and Caenorhabditis elegans model systems. Mitochondrial damage and dysfunction were observed in yeast following exposure to CPS and MA, suggesting this organelle is a major target. In the C. elegans model, the mitochondrial unfolded protein response pathway showed the most robust induction from CPS and MA treatment among stress responses examined. GABAergic neurodegeneration was observed with CPS and MA exposure. Impaired movement observed in C. elegans exposed to CPS and MA may be the result of motor neuron damage. Our analysis suggests that stress from CPS and MA results in mitochondrial dysfunction, with GABAergic neurons sensitized to these effects. These findings may aid in the understanding of toxicity from CPS and MA from high concentration exposure leading to insecticide poisoning.     

多囊卵巢综合征患者卵母细胞超微结构观察

目的 对多囊卵巢综合征（PCOS）患者卵母细胞的超微结构和线粒体DNA（mtDNA）拷贝数进行分析,探讨PCOS患者卵母细胞质量下降的原因。方法 根据临床指征,选取2017年1～12月于中国科学技术大学附属第一医院生殖医学中心因男方因素行卵胞质内单精子注射技术（ICSI）助孕的患者115例,根据是否患有PCOS分为试验组和对照组,其中试验组为PCOS患者57例,对照组为非PCOS患者58例。所有患者均接受标准长方案控制性促排卵,共收集187枚卵母细胞用于透射电镜（TEM）的超微结构分析和mtDNA拷贝数的荧光实时定量PCR检测。其中试验组52枚用于超微结构观察,另38枚用于mtDNA拷贝数检测;对照组57枚和40枚分别用于超微结构观察和mtDNA拷贝数检测。对比观察试验组与对照组来源的卵母细胞超微结构各指标：透明带、卵周隙、微绒毛、皮质颗粒、高尔基体和内质网的形态和分布、线粒体的结构与数量。结果 与对照组相比,试验组卵母细胞的透明带、卵周隙、微绒毛、皮质颗粒、高尔基体、内质网等细胞结构和细胞器没有变化。但试验组卵母细胞内异常线粒体比例（58.7%高于对照组17.7%（P<0.05）,且线粒体数量试验组（44.3±9.6）个/切片低于对照组（65.4±12.7）个/切片（P<0.05）。同时,试验组卵母细胞所含的mtDNA拷贝数为（54 390±19 139）个,低于对照组的（88 135±44 235）个（P<0.05）。结论 PCOS患者卵母细胞内线粒体结构和数量均出现改变,可能与其卵母细胞质量受损有关。