4-苯基丁酸钠通过抑制内质网应激减轻皮层神经元氧糖剥夺/再灌注损伤

4-苯基丁酸钠（4-phenylbutyric acid,4-PBA）是协助内质网中蛋白质转录后修饰和折叠的分子伴侣,故可减轻非折叠蛋白反应（unfolded protein response,UPR）及其介导的细胞凋亡。既往研究表明,4-PBA可以减轻脑组织的缺血性损伤,但采用原代皮层神经元构建氧糖剥夺/再灌注（oxygen glucose deprivation/reoxygenation, OGD/R）损伤模型,来研究4-PBA对神经元损伤的保护作用及其机制尚未见报道。本文采用原代培养的皮层神经元OGD/R损伤模型,同时给予4-PBA处理,探讨4-PBA对OGD/R诱导的神经元内质网应激（endoplasmic reticulum stress,ERS）的作用及其机制。分别采用MTT、LDH和Hoechst 33342染色法检测神经元存活率、细胞膜完整性和细胞凋亡情况。Western印迹检测ERS标志物葡萄糖调节蛋白78 (glucose regulated protein 78,GRP78),以及肌醇必需酶1（inositol requiring enzyme 1, IRE1）通路相关蛋白质的表达。Western印迹结果显示,在OGD/R后0～48 h,GRP78的表达较对照组明显升高。MTT、LDH漏出率和Hoechst 33342染色法检测显示,4-PBA显著改善OGD/R所导致的神经元存活率下降、LDH漏出率升高和细胞凋亡增加,且具有明显的剂量依赖性。通过Western印迹检测发现,4-PBA显著逆转OGD/R所致GRP78蛋白表达水平的上调。此外,对肌醇必需酶1通路相关蛋白质的检测显示,4-PBA下调氧糖剥夺/再灌注组神经元p IRE1和p JNK的表达,增加抗凋亡蛋白Bcl 2表达。上述研究结果表明,4-PBA在氧糖剥夺/再灌注情况下对神经元具有保护作用,该保护作用可能是通过抑制肌醇必需酶1信号通路介导的非折叠蛋白反应和内质网应激实现的。     

Ephrin-A3逆向通路对海马星形胶质细胞谷氨酸摄取能力的影响

目的观察EphA4介导的ephrin-A3逆向通路激活对星形胶质细胞谷氨酸摄取能力的影响。方法采用原代培养的大鼠海马星形胶质细胞,使用免疫荧光双标法定位ephrin-A3在海马星形胶质细胞上的表达,Western blot法观察糖氧剥夺(oxygen-glucose deprivation,OGD)后星形胶质细胞ephrin-A3表达水平的变化,随后实验分为三组:空白对照组(不含星形胶质细胞),药物对照组(加入IgG-Fc)和EphA4组(加入ephrin-A3逆向通路激动剂预聚集化的EphA4-Fc),分别在正常及缺血条件下的特定时间点以谷氨酸浓度测定试剂盒检测不同干预组星形胶质细胞谷氨酸摄取能力的变化。结果 ephrin-A3高表达于海马星形胶质细胞,并在缺血后出现蛋白表达水平一过性上调。与对照组相比,EphA4干预组星形胶质细胞谷氨酸摄取能力较对照组明显下降。结论 Ephrin-A3高表达于海马星形胶质细胞并参与调节星形胶质细胞谷氨酸摄取能力。     

S24795上调星形胶质细胞内源性Cryab抑制Aβ聚集的研究

该文探讨了S24795激活星形胶质细胞α7胆碱能受体(α7 nicotinic receptors,α7 n ACh Rs)上调内源性αB-晶状体蛋白(αB-crystallin,Cryab)并抑制β淀粉样蛋白(amyloidβ,Aβ)集聚的现象及其形成机制。分离24 h内新生乳鼠大脑皮质培养原代星形胶质细胞并鉴定;体外制备Aβ1-42寡聚体;将细胞分组处理。用Western blot检测细胞内Cryab、Phospho-Akt、Aβ寡聚体的水平。结果显示,S24795可以显著上调星形胶质细胞内源性Cryab蛋白质,该上调效应能被(methyllycaconitine,MLA)或LY294002抑制;S24795能够显著上调磷酸化Akt水平上调,该上调效应能被MLA或LY294002抑制;在细胞裂解液及培养基中,S24795显著增强星形胶质细胞对Aβ聚集的抑制作用,该效应被LY294002抑制。该研究结果提示,磷脂酰肌醇3激酶(phosphatidylinositol 3-kinase,PI3K)信号通路可能参与S24795激活星形胶质细胞α7 n ACh Rs上调内源性Cryab的表达,从而进一步抑制Aβ集聚。这为进一步研究S24795抑制Aβ集聚的可能机制提供了实验基础。     

13-甲基十四烷酸对大鼠脑皮层星形胶质细胞氧反常的影响

目的研究13-甲基十四烷酸(13-methyltetradecanoic Acid,13-MTD)对大鼠脑皮质星形胶质细胞氧反常的保护作用。方法传代培养新生SD乳鼠大脑皮质星形胶质原代细胞,以氧糖剥夺/再复氧糖(OGD/R)方法复制氧反常模型,OGD 10 h/R 24 h,于再复氧糖即刻分别给予13-MTD 20,40,80μg/m L(M20,M40,M80)干预,倒置显微镜动态观察星形胶质细胞形态,细胞免疫化学鉴定角质纤维酸性蛋白(glial fibrillary acidic protein,GFAP),MTT法检测线粒体活性,免疫组化法检测星形胶质细胞的水通道蛋白4(aquaporin 4,AQP4)蛋白表达。结果OGD 10 h/R 24 h损伤后,体外培养的SD乳鼠脑皮质星形胶质细胞出现明显损伤,线粒体活性显著下降(P0.01),星形胶质细胞膜AQP4蛋白表达量明显增加(P0.01);与模型组比较,13-MTD 20,40,80μg/m L可减少损伤,使线粒体活性上升、AQP4蛋白表达减少,以80μg/m L效果最好(P0.01)。结论 13-MTD可通过降低AQP4的表达,提高线粒体活性,减轻细胞水肿,进而保护氧反常诱导的星形胶质细胞损伤。     

ZnCl_2阻断电压门控质子通道对缺氧后小胶质细胞产生活性氧及促炎因子的影响

为明确电压门控质子通道(voltage-gated proton channel,Hv1)对小胶质细胞的影响,研究了Hv1在正常、激活及抑制后对小胶质细胞活性氧、促炎因子产生的影响及机制,该研究使用原代培养的小胶质细胞,利用免疫荧光染色明确Hv1表达。用Hv1非特异性抑制剂Zn Cl2阻断该通道,用DCFH-DA染色、Real-time PCR观察糖氧剥夺(oxygen glucose deprivation,OGD)处理后小胶质细胞产生活性氧(reactive oxygen species,ROS)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)水平的变化。采用Western blot检测Hv1和Nox2蛋白质水平。实验结果显示,小鼠脑部小胶质细胞可检测到Hv1通道的表达;单纯ODG组缺氧后小胶质细胞ROS、TNF-α、IL-1β的产生明显增加;而OGD加Zn Cl2干预组,小胶质细胞ROS、TNF-α、IL-1β的产生较单纯OGD组显著降低;Western blot显示,OGD导致小胶质细胞中Hv1和Nox2蛋白质水平显著增加。以上结果表明,小鼠脑部小胶质细胞存在Hv1通道蛋白质,Zn Cl2阻断该通道可降低OGD诱导的小胶质细胞ROS和TNF-α、IL-1β的产生,该抑制作用可能与其抑制NADPH氧化酶的作用相关。     

TRPV2激活对缺氧再灌注时体外培养星形胶质细胞神经生长因子释放的影响

神经生长因子对脑缺血后神经元的存活有重要意义。该研究观察了TRPV2激活剂2APB对体外缺血再灌注模型中原代培养大鼠大脑皮层星形胶质细胞神经生长因子释放的影响。将原代培养大鼠大脑皮层星形胶质细胞分为2APB组（0．5mmol／L）和对照组（不含2APB）,在糖氧剥夺情况下培养2h,然后恢复正常全培养基复氧培养48h。用Westem blot检测星形胶质细胞神经生长因子的表达水平;用ELISA检测星形胶质细胞条件培养液中神经生长因子的含量。结果表明,0．5mmol／L2APB可以诱导正常情况下及糖氧剥夺再灌注情况下体外培养星形胶质细胞NGF的合成和释放LP〈0．01）。此外,JNK阻滞剂可抑制糖氧剥夺再灌注情况下2APB诱导的星形胶质细胞神经生长因子的释放。综上．TRPV2激活可以影响糖氧剥夺再灌注情况下体外培养星形胶质细胞神经生长因子的合成和释放。TRPV2有可能成为脑缺血再灌注后的潜在治疗靶点。     

氧化低密度脂蛋白诱导巨噬细胞内质网应激及CD36的可能作用

本文旨在研究在鼠源巨噬细胞泡沫化过程中氧化低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)对巨噬细胞内质网应激(endoplasmic reticulum stress,ERS)的诱导作用及其机制。体外培养RAW264.7巨噬细胞,分别给予ox-LDL(25、50和100mg/L)、抗CD36抗体+ox-LDL和衣霉素(tunicamycin,TM)等不同处理。采用油红O染色观察细胞内脂质蓄积情况,酶比色法测定细胞内总胆固醇含量,免疫细胞化学法检测ERS标志分子糖调节蛋白94(glucose-regulated protein94,GRP94)表达,免疫印迹法检测GRP94及未折叠蛋白反应关键分子p-IRE1(phosphorylated inositol-requiring enzyme1)和X盒结合蛋白1(X box binding protein1,XBP1)蛋白表达水平。结果显示,不同浓度(25、50和100mg/L)ox-LDL处理细胞24h后,胞浆内可见大量油红O染色阳性脂质颗粒,细胞内总胆固醇含量明显增加,分别为空白对照组的2.1倍、2.8倍和3.1倍;使用抗CD36抗体阻断ox-LDL的摄入,可显著减少100mg/Lox-LDL所致的细胞内胆固醇蓄积。不同浓度ox-LDL和ERS诱导剂TM均可显著增加GRP94及其上游信号分子p-IRE1和XBP1蛋白表达,且表达强度随着ox-LDL诱导浓度的增加而增强;抗CD36抗体显著抑制100mg/Lox-LDL所致的上述3种蛋白表达上调。上述结果提示,ox-LDL可呈剂量依赖性诱导RAW264.7巨噬细胞产生ERS,激活未折叠蛋白反应信号通路;该过程可能由清道夫受体CD36所介导。     

内质网应激介导氧化低密度脂蛋白所诱导的巨噬细胞清道夫受体A1上调

本文旨在研究内质网应激(endoplasmic reticulum stress,ERS)是否介导氧化低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)所诱导的巨噬细胞清道夫受体A1(scavenger receptor A1,SR-A1)上调。体外培养RAW264.7巨噬细胞,给予20mmol/L ERS抑制剂4-苯丁酸(4-phenylbutyric acid,PBA)处理30 min后,再加入ox-LDL(50 mg/L)继续培养12 h或2 mg/L ERS诱导剂衣霉素(tunicamycin,TM)或2μmol/L毒胡萝卜素(thapsigagin,TG)继续培养4 h。另外培养巨噬细胞分别给予0.5、1和2 mg/L TM处理4 h或给予2 mg/L TM处理1、2和4 h。采用试剂盒检测细胞内总胆固醇(total cholesterol,TC)含量;分别采用免疫印迹法和实时定量聚合酶链反应(real-time PCR)技术检测SR-A1和ERS标志分子糖调节蛋白78(glucose-regulated protein 78,GRP78)蛋白和mRNA表达变化;采用多功能酶标仪检测Dil-ox-LDL摄取情况。结果显示,PBA显著抑制ox-LDL所诱导的巨噬细胞内胆固醇蓄积。ox-LDL可显著上调SR-A1和GRP78表达,而PBA可明显抑制ox-LDL所诱导的SR-A1上调(P0.05),并使GRP78降低39.3%(P=0.057)。TM明显上调SR-A1蛋白表达,并促进巨噬细胞对ox-LDL的摄取,且呈浓度和时间依赖性,但对SR-A1转录水平没有明显影响,且ERS另一诱导剂TG也可明显上调SR-A1表达;而PBA则明显抑制TM和TG所诱导的上述变化。以上结果表明,ERS在ox-LDL所诱导的SR-A1上调中具有重要作用,进而促使巨噬细胞摄取更多的ox-LDL,导致泡沫细胞形成。     

TRPC3/6/7通道在氧糖剥夺星形胶质细胞凋亡中的作用

目的 研究TRPC3/6/7在氧糖剥夺/复氧(oxygen glucose deprivation/reoxygenation,OGD/R)后对星形胶质细胞凋亡的影响及其可能机制.方法 将体外培养星形胶质细胞分为空白对照组、野生型(wild type,WT)OGD/R组、TRPC3/6/7基因敲除OGD/R组,通过We...     

神经元-小胶质细胞EphA4/ephrin通路调控小胶质细胞介导的缺血后炎性损伤

目的观察神经元-小胶质细胞间EphA4/ephrin信号通路在脑缺血后的炎性损伤中的作用及机制。方法建立神经元-小胶质细胞混合培养体系和糖氧剥夺再复氧(oxygen-glucose deprivation and reperfusion, OGD/R)模型,使用预聚集化的EphA4-Fc激动小胶质细胞ephrin配体,检测OGD/R后的细胞凋亡、小胶质细胞增殖和亚型极化以及小胶质细胞功能改变。结果 EphA4受体高表达于原代神经元,与对照组相比,预聚集化EphA4-Fc干预加重OGD/R导致的细胞凋亡,促进小胶质细胞增殖以及向M1型(促炎型)极化(炎症表型)。结论神经元-小胶质细胞间EphA4/ephrin信号通路通过调控小胶质细胞亚型极化参与脑缺血后的炎性损伤的过程。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势, 重大成果频出, 具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈, 如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中, 有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外, 值得一提的是, 长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果“水稻高产优质性状形成的分子机理及品种设计”荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理, 旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态, 与广大读者共同分享我国科学家所取得的辉煌成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义.综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望.     

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.     

Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.