Lysosomal membrane permeabilization is involved in oxidative stress-induced apoptotic cell death in LAMP2-deficient iPSCs-derived cerebral cortical neurons

Patients with Danon disease may suffer from severe cardiomyopathy, skeletal muscle dysfunction as well as varying degrees of mental retardation, in which the primary deficiency of lysosomal membrane-associated protein-2 (LAMP2) is considerably associated. Owing to the scarcity of human neurons, the pathological role of LAMP2 deficiency in neural injury of humans remains largely elusive. However, the application of induced pluripotent stem cells (iPSCs) may shed light on overcoming such scarcity.In this study, we obtained iPSCs derived from a patient carrying a mutated LAMP2 gene that is associated with Danon disease. By differentiating such LAMP2-deficient iPSCs into cerebral cortical neurons and with the aid of various biochemical assays, we demonstrated that the LAMP2-deficient neurons are more susceptible to mild oxidative stress-induced injury.The data from MTT assay and apoptotic analysis demonstrated that there was no notable difference in cellular viability between the normal and LAMP2-deficient neurons under non-stressed condition. When exposed to mild oxidative stress (10 μM H₂O₂), the LAMP2-deficient neurons exhibited a significant increase in apoptosis. Surprisingly, we did not observe any aberrant accumulation of autophagic materials in the LAMP2-deficient neurons under such stress condition.Our results from cellular fractionation and inhibitor blockade experiments further revealed that oxidative stress-induced apoptosis in the LAMP2-deficient cortical neurons was caused by increased abundance of cytosolic cathepsin L. These results suggest the involvement of lysosomal membrane permeabilization in the LAMP2 deficiency associated neural injury.     

Partial contribution of mitochondrial permeability transition to t-butyl hydroperoxide-induced cell death

Mitochondrial permeability transition (MPT) is thought to determine cell death under oxidative stress. However, MPT inhibitors only partially suppress oxidative stress-induced cell death. Here, we demonstrate that cells in which MPT is inhibited undergo cell death under oxidative stress. When C6 cells were exposed to 250 μM t-butyl hydroperoxide (t-BuOOH), the loss of a membrane potential-sensitive dye (tetramethylrhodamine ethyl ester, TMRE) from mitochondria was observed, indicating mitochondrial depolarization leading to cell death. The fluorescence of calcein entrapped in mitochondria prior to addition of t-BuOOH was significantly decreased to 70% after mitochondrial depolarization. Cyclosporin A suppressed the decrease in mitochondrial calcein fluorescence, but not mitochondrial depolarization. These results show that t-BuOOH induced cell death even when it did not induce MPT. Prior to MPT, lactate production and respiration were hampered. Taken together, these data indicate that the decreased turnover rate of glycolysis and mitochondrial respiration may be as vital as MPT for cell death induced under moderate oxidative stress.     

番茄AT-hook基因家族的鉴定及胁迫条件下的表达分析

AT-hook蛋白家族在植物生长发育、器官构建及逆境胁迫和激素信号应答中发挥重要作用。本研究在番茄基因组范围内,利用生物信息学方法对番茄AT-hook基因家族的成员、分布、结构和功能进行分析。结果表明,番茄AT-hook家族包含32个成员,分为3种类型,其中类型Ⅰ含有13个成员;遗传进化分析表明番茄AT-hook基因成员与拟南芥家族基因具有相似分类。利用实时荧光定量PCR对番茄32个基因开展组织表达分析,结果表明AT-hook基因具有表达差异,主要在根和花中表达较高。氧化胁迫分析结果表明,32个基因受ABA、SA、盐、高温和低温诱导表达,其中部分基因显著上调或下调表达,很可能参与了番茄逆境胁迫条件下的防御应答反应。本研究结果将为番茄AT-hook家族基因的深入研究提供依据,为进一步解析番茄AT-hook基因的功能奠定基础。     

血清尿酸、超敏C 反应蛋白与老年永久性房颤的关系

目的:探讨血清尿酸(UA)、超敏C反应蛋白(hs-CRP)、左心房内径(LAD)与老年永久性房颤的相关性。方法:选取2012年8月至2015年9月于首都医科大学宣武医院综合科住院的老年永久性房颤患者78例作为房颤组,选取同期住院窦性心律且无房颤病史的老年患者72例作为对照组,记录各组一般资料及超声心动图、尿酸、hs-CRP水平等,进行比较及相关性分析。结果:1与对照组相比,房颤组血清UA及hs CRP水平、左心房内径大小明显增高(P0.05),2以房颤是否发生为因变量,多因素logistic回归分析显示血清尿酸(OR=2.016,P=0.004)、左房内径(OR=4.180,P=0.001)和hs-CRP(OR=2.846,P=0.002)是老年永久性房颤发生的独立危险因素。3房颤组患者血清尿酸与hs-CRP水平呈正相关(r=0.28,P0.05),尿酸与左心房内径大小呈轻度正相关(r=0.12,P0.05)。结论:血清尿酸、hs-CRP、左房内径是老年永久性房颤发生的独立危险因素;尿酸参与的炎症反应和结构重构可能参与老年永久性房颤的发生。     

Cell‐to‐cell heterogeneity emerges as consequence of metabolic cooperation in a synthetic yeast community

Cells that grow together respond heterogeneously to stress even when they are genetically similar. Metabolism, a key determinant of cellular stress tolerance, may be one source of this phenotypic heterogeneity, however, this relationship is largely unclear. We used self‐establishing metabolically cooperating (SeMeCo) yeast communities, in which metabolic cooperation can be followed on the basis of genotype, as a model to dissect the role of metabolic cooperation in single‐cell heterogeneity. Cells within SeMeCo communities showed to be highly heterogeneous in their stress tolerance, while the survival of each cell under heat or oxidative stress, was strongly determined by its metabolic specialization. This heterogeneity emerged for all metabolite exchange interactions studied (histidine, leucine, uracil, and methionine) as well as oxidant (H₂O₂, diamide) and heat stress treatments. In contrast, the SeMeCo community collectively showed to be similarly tolerant to stress as wild‐type populations. Moreover, stress heterogeneity did not establish as sole consequence of metabolic genotype (auxotrophic background) of the single cell, but was observed only for cells that cooperated according to their metabolic capacity. We therefore conclude that phenotypic heterogeneity and cell to cell differences in stress tolerance are emergent properties when cells cooperate in metabolism.     

氧化应激反应与膝关节骨性关节炎的相关性探究

目的:了解膝关节骨性关节炎患者机体的氧化应激状态,探讨氧化应激反应与膝关节骨性关节炎发生、发展的关系。方法:收集膝关节骨性关节炎患者及健康人群的血清,采用分光光度法测定和比较其SOD、GSH-Px、MDA水平。结果:与健康对照人群相比,膝关节骨性关节炎患者体内SOD、GSH-Px酶类抗氧化剂活力显著增强(P0.05);MDA脂质过氧化损伤产物明显降低(P0.05)。结论:膝关节骨性关节炎患者体内氧化还原状态发生了改变,可能处于抗氧化应激的慢性代偿状态;氧化应激反应参与了骨性关节炎的发生、发展过程。     

氯化锂对脓毒症大鼠血清促炎细胞因子及氧化损伤的影响

目的:探讨氯化锂对脓毒症大鼠的促炎细胞因子及氧化损伤的影响。方法:将50只Wistar大鼠按随机数字表随机分为假手术组(S组,n=10)、模型组(CLP组,n=20)、氯化锂干预组(CLP+Li Cl组,n=20),每组又分为8 h、16 h、24 h 3个时间观察点亚组,CLP组采用盲肠结扎穿孔术(CLP)制备脓毒症模型。氯化锂干预组于CLP手术后立即给予腹腔注射Li Cl溶液(50 mg/Kg),假手术组和CLP组给予等量生理盐水腹腔注射。每组每只大鼠分别于术后8 h、16 h、24 h采集眼眶静脉血检测其中肿瘤坏死因子α(TNF-α)、白介素6(IL-6)、超氧化物歧化酶(SOD)、丙二醛(MDA)浓度,并记录术后24 h各组大鼠生存率。结果:与S组相比,CLP组及CLP+Li Cl组各时间点血清TNF-α、IL-6和MDA的浓度上升,SOD浓度降低,差异有统计学意义(P0.05);与CLP组同时间点比较,CLP+Li Cl组血清TNF-α、IL-6和MDA的浓度下降,SOD浓度升高;与CLP组术后24h生存率相比,CLP+Li Cl组生存率提高,差异有统计学意义(P0.05)。结论:氯化锂可能通过抑制炎性细胞因子释放以及减轻氧化应激损伤的机制实现提高脓毒症大鼠生存率的作用。     

二甲双胍联合西格列汀对2型糖尿病患者氧化应激、胰岛素抵抗的影响

目的:探讨二甲双胍联合西格列汀对2型糖尿病患者氧化应激、胰岛素抵抗的影响。方法:收集我院就诊或住院治疗的80例2型糖尿病患者,随机分为实验组和对照组,每组40例。两组患者入院后均给予相应的治疗措施,对照组患者给予二甲双胍250 mg/次,2次/d;实验组患者在对照组的基础上给予西格列汀100 mg/次,1次/d,治疗均连续8周。治疗结束后对患者血清丙二醛(MDA)、8异前列腺素F2α(8-iso-PGF2α)、空腹血糖(FBG)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)以及患者临床治疗效果进行检测并比较。结果:与治疗前相比,治疗后两组患者MDA、8-iso-PGF2α、FBG、FINS以及HOMA-IR水平均下降(P0.05);与对照组相比,实验组患者MDA、8-iso-PGF2α、FBG、FINS以及HOMA-IR水平较低(P0.05),临床治疗总有效率较高(P0.05)。结论:二甲双胍联合西格列汀能够降低2型糖尿病患者血糖水平,降低MDA、8-iso-PGF2α水平,减轻氧化应激反应,降低胰岛素抵抗,临床疗效较好。     

椎弓根钉棒系统加植骨融合治疗胸腰椎爆裂性骨折并脊髓损伤的 临床研究

目的:探讨椎弓根钉棒系统加植骨融合治疗胸腰椎爆裂性骨折并脊髓损伤的疗效。方法:回顾性分析2010年3月至2014年12月,采用椎弓根钉棒系统加植骨融合治疗93例胸腰椎爆裂性骨折并脊髓损伤患者的资料,男56例,女37例。致伤原因:交通事故伤27例,高处坠落伤47例,重物压伤19例。骨折节段:L1骨折22例,L2骨折16例,L3骨折6例,T11骨折15例,T12骨折34例。结果:本研究共93例患者,所有患者经过一般12个月的随访,其中平均随访13.8月(10-16月)。与术前相比,患者术后6个月伤椎前缘高度比值明显增加,Cobb角值和椎管占位率明显降低(t=6.167,7.241,7.143,P0.05)。术后12个月伤椎前缘高度比值明显增加,Cobb角值和椎管占位率明显降低(t=9.345,11.541,11.263,P0.05)。且患者术后12个月与术后6个月在伤椎前缘高度比值、Cobb角、椎管占位率上比较,差异具有统计学意义(t=9.632,8.154,7.415,P0.05),根据Frankel神经分级,术后大部分患者神经功能有所恢复。其中,Frankel分级为A的患者有35例恢复,术后有效恢复率为87.5%;B级患者有25例恢复,术后有效恢复率89.3%。C级和D级患者术后有效恢复率均为100%,B,C,D级患者与A级患者有效恢复率相比,差异没有统计学意义(x~2=0.051,2.196,1.253,P0.05),随访12个月期间,2例患者术后5个月出现内固定物松动,1例术后12个月发生螺钉断裂,其余患者无伤口感染、肺部感染、深静脉血栓等并发症发生。结论:椎弓根钉棒系统加植骨融合能有效治疗胸腰椎爆裂性骨折并脊髓神经损伤,术后患者神经功能恢复较好,并发症较少,值得临床推广使用。     

酒精性肺疾病的临床研究及进展

酒精对全身器官均有损害,随着研究的深入,酒精性肺疾病逐渐被人们重视。基于酒精的挥发性和肺脏的丰富血供,酒精可以通过支气管循环从纤毛上皮进入到气道,汽化的酒精还可以沉积回气道随呼气再次被释放,这种重复循环使局部气道上皮细胞持续暴露于高浓度酒精下。酒精在肺脏的代谢分为氧化和非氧化代谢两种途径,氧化代谢产物乙醛可引起氧化应激,并产生大量的ROS和自由离子。酒精可影响肾素-血管紧张素系统,提高血管紧张素II水平,并引起内皮细胞应激。酒精还可降低肺脏内还原型谷胱甘肽含量,损害机体先天性和获得性免疫功能。本文将阑述酒精在肺脏的代谢途径及代谢产物对肺脏的损害,其引起重要的应激反应对肺脏均造成损害,是发生肺炎、慢性阻塞性肺疾病、急性呼吸窘迫征等肺疾病的重要因素之一。作者通过酒精对肺脏的作用机制,总结最新的治疗措施。