人参皂苷Rb1抑制β淀粉样蛋白25-35诱导的皮层神经元tau蛋白过度磷酸化

目的探讨人参皂苷Rb1对凝聚态β-AP_25-35诱导的胎鼠皮层神经元tau蛋白过度磷酸化的影响及其可能的作用机制。方法通过蛋白免疫印迹法和免疫细胞化学染色法检测神经元tau蛋白磷酸化水平、总tau蛋白水平和糖原合成酶3β(GSK-3β)的蛋白表达水平。结果凝聚态β-AP_25-35(20 μmol·L^-1)作用于皮层神经元12 h，tau蛋白磷酸化水平和总tau蛋白水平均增高，同时GSK-3β蛋白表达也增多。用人参皂苷Rb1或GSK-3β特异性抑制剂氯化锂预处理后，凝聚态β-AP_25-35诱导的tau蛋白的过度磷酸化受到明显抑制，同时GSK-3β的表达也降低。结论人参皂苷Rb1可通过抑制GSK-3β的表达来抑制凝聚态β-AP_25-35诱导的皮层神经元tau蛋白的过度磷酸化。     

人参皂苷Rb1可能通过CDK5途径减轻Aβ25-35诱导的胎鼠海马神经元tau蛋白过度磷酸化

观察人参皂苷Rb1对Aβ_25-35诱导的海马神经元tau蛋白过度磷酸化的影响，并探讨其对周期依赖性蛋白激酶(cyclin-dependent kinase 5，CDK5)及激动亚基p25/p35的可能作用。通过蛋白免疫印迹法和免疫细胞化学染色法检测胎鼠海马神经元tau蛋白在Thr²⁰⁵、Ser³⁹⁶和Ser⁴⁰⁴位点的磷酸化水平，及CDK5的两个亚基cdk5和p25/p35的蛋白水平。20 μmol·L^-1凝聚态Aβ_25-35作用于海马神经元12 h，可使海马神经元tau蛋白在Thr²⁰⁵、Ser³⁹⁶和Ser⁴⁰⁴位点的磷酸化水平增高，p25的数量增多，但并不影响cdk5亚基的表达。人参皂苷Rb1可减轻凝聚态Aβ_25-35诱导的海马神经元tau蛋白的过度磷酸化，抑制p35的降解并减少海马神经元p25的生成。人参皂苷Rb1可能通过CDK5途径减轻Aβ_25-35诱导的胎鼠海马神经元tau蛋白过度磷酸化。     

p25/cdk5可能参与人参皂苷Rb1减轻Aβ_(25-35)诱导的tau蛋白过度磷酸化

目的探讨在Aβ25-35诱导的皮层神经元tau蛋白过度磷酸化中,人参皂苷Rb1对周期依赖性蛋白激酶(cyc lin-de-pendent k inase 5,CDK 5)的激动亚基p35/p25的影响。方法通过蛋白免疫印迹法和免疫细胞化学染色法检测胎鼠皮层神经元CDK 5的两个亚基cdk5和p35/p25的蛋白水平,以及CDK 5的磷酸化底物tau蛋白在Ser199/202、Thr205、Ser396和Ser404位点的磷酸化水平。结果凝聚态Aβ25-35(20μmol.L-1)作用于皮层神经元12 h,可使皮层神经元中p25的数量增多,以及tau蛋白在Ser199/202、Thr205、Ser396和Ser404位点的磷酸化水平增高,但对cdk 5亚基表达水平影响并不明显。Rb1和calpain特异性抑制剂calpeptin可减少皮层神经元p25的生成,同时人参皂苷Rb 1和CDK 5特异性抑制剂roscovitine可减轻凝聚态Aβ25-35诱导的皮层神经元tau蛋白的过度磷酸化水平。结论p25/cdk 5可能参与人参皂苷Rb1减轻Aβ25-35诱导的tau蛋白过度磷酸化。     

慢性孵育β-淀粉样肽(25-35)对培养大鼠海马神经元外向钾电流的影响

目的　研究慢性孵育β-淀粉样肽_(25-35) (β-AP_25-35)对海马神经元上瞬时外向钾电流(I_A)和延迟整流钾电流(I_K)的影响。方法　在培养的大鼠海马神经元上用膜片钳全细胞记录钾通道电流。结果　β-AP_25-35 3μmol·L^-1 孵育细胞24h ,I_K 电流幅度增加(44.3±5.4)% ,电流密度由(30.4±6.4)pA·PF^-1 增加至(43.8±4.7)pA·PF^-1 ;β-AP_25-3510μmol·L^-1 孵育12h ,I_K 电流幅度增加(69.8±4.1) % ,电流密度增加至(51.6±7.9)pA·PF^-1,呈浓度依赖性;β-AP_25-35引起的I_K 增加对TEA 5mmol·L^-1 敏感;β-AP_25-35上调I_K 的作用主要发生在β-AP_25-355用药后48h内。β-AP_25-35对I_A无显著性影响。结论　β-AP_25-35选择性地增加海马神经元上I_K,这一作用可能与β-AP的神经毒性有关     

人参皂苷Rb1调控MAPK通路改善小鼠脑缺血再灌注诱导血脑屏障损伤的作用研究

目的 探讨人参皂苷Rb₁对小鼠脑缺血再灌注诱导的血脑屏障（BBB）损伤的作用及机制。方法 将C57BL/6小鼠随机分为假手术组、模型组和人参皂苷Rb₁低、中、高剂量（5、10、20 mg·kg^-1）组,采用线栓法栓塞颈内动脉1 h后复灌建立脑缺血再灌注损伤模型,假手术组不栓塞,其余操作同模型小鼠。缺血1 h后ip相应药物,于再灌注24 h后处死取材。采用伊文思蓝染色法检测各组小鼠BBB损伤程度;采用实时荧光定量PCR （qRT-PCR）法检测各组小鼠脑组织中炎症因子白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）以及紧密连接蛋白1（ZO-1）、闭合蛋白（Occludin）的mRNA表达水平;同时采用Western blotting检测各组小鼠脑组织中ZO-1、Occludin蛋白,金属基质蛋白酶-2（MMP-2）、基质金属蛋白酶-9（MMP-9）以及MAPK通路相关蛋白磷酸化的表达水平。结果 与模型组相比,人参皂苷Rb₁可显著减少脑缺血再灌注小鼠脑组织中伊文思蓝的渗漏量（P<0.05）,显著降低脑组织中IL-1β、IL-6和TNF-α的mRNA转录水平（P<0.05、0.01）;显著上调ZO-1和Occludin的mRNA转录和蛋白表达水平（P<0.05、0.01）;显著降低MMP-2、MMP-9的蛋白表达水平（P<0.05、0.01）;显著抑制MAPK通路p38、JNK及ERK磷酸化蛋白的表达（P<0.05、0.01）。结论 人参皂苷Rb₁对小鼠脑缺血再灌注诱导的BBB损伤具有一定的改善作用,其作用机制可能与抑制MAPK信号通路激活,减少MMP-2、MMP-9蛋白的表达,进而减轻对ZO-1、Occludin等紧密连接蛋白的降解有关。     

左旋黄皮酰胺对冈田酸和β淀粉样肽25-35神经毒性的保护作用

探讨左旋黄皮酰胺对冈田酸(okadaic acid，OA)诱导的人神经瘤细胞(SH-SY5Y)和去卵巢(ovariectomy，OVX)及单侧侧脑室注射Aβ_25-35所致神经元损伤的保护作用。通过MTT试验、LDH释放测定试验、Hoechst 33258荧光染色试验以及SH-SY5Y细胞检测，考察左旋黄皮酰胺拮抗冈田酸诱导的细胞毒作用。通过避暗试验、电镜检测、Nissl体染色及HE染色，考察左旋黄皮酰胺对去卵巢及侧脑室注射Aβ_25-35大鼠神经元的保护作用。左旋黄皮酰胺可明显拮抗冈田酸诱导的细胞毒作用，提高去卵巢及侧脑室注射Aβ_25-35大鼠的学习记忆能力，保护海马及皮层神经元。左旋黄皮酰胺可拮抗冈田酸及Aβ_25-35诱导的神经毒性，具有神经保护作用。     

五味子乙素抑制M146L细胞Aβ42生成的机制研究

目的研究五味子乙素抑制M146L细胞Aβ₄₂生成的机制。方法体外培养高效表达Aβ42的M146L细胞株，分别加入不同浓度的五味子乙素(1.67，5.00和15.00 μg·mL^-1)、 β分泌酶抑制剂(S4562，100.00 μg·mL^-1)和γ分泌酶抑制剂(S2188，13.68 μg·mL^-1)。用CCK-8(cell counting kit-8)比色法检测不同处理对M146L细胞活性的影响；用ELISA法测定M146L细胞所分泌的Aβ₄₂的变化；用Western blotting检测APP的β分泌酶剪切产物C99蛋白的含量变化，结合用β和γ分泌酶活性试剂盒，检测五味子乙素对这两种酶活性的影响。结果不同处理因素对M146L细胞的存活率均无影响，不具有细胞毒作用。中、高剂量的五味子乙素均不同程度地抑制M146L细胞分泌Aβ₄₂及γ分泌酶的活性，但都不改变M146L细胞C99蛋白的含量及β分泌酶的活性。结论五味子乙素可抑制γ分泌酶活性，其降低Aβ₄₂生成是通过抑制γ分泌酶的活性来实现的。     

HPLC-MS/MS测定同济2号颗粒剂中黄芪甲苷、绿原酸、人参皂苷Rg1、人参皂苷Rb1和三七皂苷R1

目的 建立HPLC-MS/MS同时测定同济2号颗粒中5个主要活性成分黄芪甲苷、绿原酸、人参皂苷Rg₁、人参皂苷Rb₁及三七皂苷R₁的方法。方法 以水(0.1%甲酸)-乙腈(0.1%甲酸)为流动相,梯度洗脱,体积流量为0.4 mL/min。YMC-Pack Pro C₈色谱柱分离,采用电喷雾离子源(ESI源),负离子模式,以选择性离子监测模式(SIM)进行测定。监测离子分别是m/z 829(黄芪甲苷)、m/z 353(绿原酸)、m/z 845(人参皂苷Rg₁)、m/z 1 108(人参皂苷Rb₁)、m/z 932(三七皂苷R₁)。结果 黄芪甲苷、绿原酸、人参皂苷Rg₁、人参皂苷Rb₁和三七皂苷R₁分别在0.075～2.4、0.95～30.3、1.71～54.72、1.12～35.92、0.45～14.28 μg/mL与峰面积呈良好线性关系。结论 该方法专属性好,灵敏度高,准确快捷,适用于同济2号颗粒的快速检测,为该药的质量标准提供依据。     

药学学报第43卷第1—12期文题分类索引

药理学双环醇对四环素诱发小鼠急性脂肪肝的保护作用唐韬,李燕(23)………………………………………………………………人参皂苷Rb1通过JNK/p38 MAPK途径减轻Aβ25-35诱导的胎鼠皮层神经元tau蛋白过度磷酸化……………………宋锦秋,陈晓春,张静,黄天文,曾育琦,沈杰,陈丽敏(29)三     

大黄酸对人肾小球系膜细胞功能的影响

目的探讨大黄酸防治糖尿病肾病的作用机制。方法用细胞培养、ELISA、明胶酶谱及免疫沉淀、Western blot等技术,研究了大黄酸对肾小球系膜细胞转化生长因子(TGFβ₁)、基质金属蛋白酶-2,-9(MMP-2和MMP-9)及p38活化丝裂原活化蛋白激酶(p38MAPK)活性的作用。结果大黄酸可显著抑制肾小球系膜细胞的增殖,对抗高糖诱导肾小球系膜细胞TGFβ₁活性升高的作用;对高糖诱导肾小球系膜细胞MMP-2,MMP-9,pro-MMP-2及pro-MMP-9的活性增加无明显影响,但可明显对抗高糖引起的肾小球系膜细胞p38MAPK活性增加。结论大黄酸减少FN的分泌可能与其降低p38MAPK及TGFβ₁活性有关。     

氯化锂抑制β-淀粉样蛋白诱导细胞Tau蛋白磷酸化

目的探讨GSK-3β抑制剂氯化锂(LiCl)在β-淀粉样蛋白25～35片断(Aβ25-35)诱导的细胞Tau蛋白磷酸化中的作用及机制。方法MTT法观察不同浓度的LiCl(1、5、10、20mmol.L-1)单独作用24h,对SH-SY5Y细胞存活率的影响;20μmol.L-1的凝聚态Aβ25-35作用于SH-SY5Y细胞不同时间点,蛋白免疫印迹法研究Tau蛋白磷酸化位点(Ser199、Ser396及Tau1)水平的变化;LiCl(20mmol.L-1)预处理细胞1h后,观察Aβ的作用有无变化及可能的作用机制。结果不同浓度的LiCl作用24h后,MTT法示细胞存活率无明显变化(P>0.05);20μmol.L-1Aβ25-35作用不同时间点后,Tau蛋白在Ser396、Ser199位点的磷酸化水平在3h逐渐增加,6h达到最高峰,12h后又逐渐下降,在这3个时间点的增加量均具有统计学意义(P<0.05),而对非磷酸化Tau1没有影响(P>0.05);LiCl预处理可抑制Aβ25-35的作用(P<0.05),并可诱导失活形式的GSK-3β在Ser9位点的磷酸化(p-GSK-3βSer9)表达增高。结论GSK-3β参与了Aβ25-35诱导细胞Tau蛋白磷酸化的作用,LiCl可通过诱导失活形式的p-GSK-3βSer9表达增高而抑制GSK-3β的活性,进而抑制Aβ诱导的细胞Tau蛋白磷酸化。该实验为研究AD的发病机制及探索有效治疗药物提供了重要的理论基础。     

HMGB1 increases RAGE expression in vascular smooth muscle cells via ERK and p-38 MAPK-dependent pathways

The increased expression of receptors for advanced glycation end-product (RAGE) is known as a key player in the progression of vascular remodeling. However, the precise signal pathways regulating RAGE expression in vascular smooth muscle cells (VSMCs) in the injured vasculatures are unclear. Given the importance of mitogen-activated protein kinase (MAPK) signaling in cell proliferation, we investigated the importance of MAPK signaling in high-mobility group box 1 (HMGB1)-induced RAGE expression in VSMCs. In HMGB1 (100 ng/ml)-stimulated human VSMCs, the expression of RAGE mRNA and protein was increased in association with an increase in AGE-induced VSMC proliferation. The HMGB1-induced RAGE expression was attenuated in cells pretreated with inhibitors for ERK (PD98059, 10 μM) and p38 MAPK (SB203580, 10 μM) as well as in cells deficient in ERK and p38 MAPK using siRNAs, but not in cells deficient of JNK signaling. In cells stimulated with HMGB1, the phosphorylation of ERK, JNK, and p38 MAPK was increased. This increase in ERK and p38 MAPK phosphorylation was inhibited by p38 MAPK and ERK inhibitors, respectively, but not by JNK inhibitor. Moreover, AGE-induced VSMC proliferation in HMGB1-stimulated cells was attenuated in cells treated with ERK and p38 MAPK inhibitors. Taken together, our results indicate that ERK and p38 MAPK signaling are involved in RAGE expression in HMGB1-stimulated VSMCs. Thus, the ERK/p38 MAPK-RAGE signaling axis in VSMCs was suggested as a potential therapeutic target for vascular remodeling in the injured vasculatures.     

MAP激酶家族在淀粉样β蛋白片段25～35引起的大鼠海马炎症反应及细胞凋亡中的作用(英文)

目的　研究淀粉样β蛋白片段2 5～35(Aβ2 5～35)引起的大鼠海马炎症反应、细胞凋亡机制及抗炎药物布洛芬的保护作用。方法　大鼠灌胃给予布洛芬7.5mg·kg- 1,连续应用3周,脑室内单次注射Aβ2 5～35(10 μL ,1mmol·L- 1) ,注射后继续应用布洛芬1周后,取脑,进行尼氏染色和胶质原纤维酸性蛋白(GFAP)免疫细胞化学染色,研究海马CA1区锥体神经元形态学改变和星形胶质细胞激活。Western印迹观察白细胞介素 1β(IL 1β) ,胞外信号调节激酶1/ 2 (ERK1/ 2 ) ,有丝分裂原活化蛋白激酶p38(p38MAPK) ,蛋白激酶C(PKC)和半胱氨酸天冬氨酸蛋白酶 3(caspase 3)蛋白表达。RT PCR分析IL 1βmRNA表达水平。结果　脑室内注射Aβ2 5～35可引起海马CA1区星形胶质细胞激活和浸润,IL 1β蛋白表达和IL 1βmRNA表达水平明显增加,这种炎症反应伴有海马CA1区锥体神经元损伤。另外,Aβ2 5～35也能引起磷酸化的p38MAPK蛋白表达较对照组明显增加,从对照组0 .16 7±0 .0 91增加到0 .4 97±0 .0 5 9(P <0 .0 1,n =4 )。使磷酸化的ERK1/ 2蛋白表达下调,ERK1的表达从对照组0 .14 6±0 .0 10下降到0 (P <0 .0 1,n =4 )。ERK2表达从对照组的0 .4 12±0 .0 5 4下降到0 .131±0 .0 38(P <0 .0 1,n =4 )。这些改变伴随有caspase 3蛋白表达的增加     

Microcystin-LR induces cytoskeleton system reorganization through hyperphosphorylation of tau and HSP27 via PP2A inhibition and subsequent activation of the p38 MAPK signaling pathway in neuroendocrine (PC12) cells

Cyanobacteria-derived microcystin-LR (MC-LR) commonly characterized as a hepatotoxin has recently been documented to show potential neurotoxicity, but the detailed neurotoxic effects of MC-LR and its mechanisms are unclear. In the present study, the neuroendocrine PC12 cell line was used to investigate whether MC-LR causes alterations of neuronal morphology and abnormalities in the phosphorylation status of cytoskeletal-associated proteins, and to elucidate the underlying mechanisms. The results showed that treatment of PC12 cells with MC-LR-triggered microtubule (MT) and actin cytoskeleton rearrangement, leading to a loss of their filamentous distribution and the display of a similar rearrangement pattern with decreased amounts of tubules or actin fibers in the cytosol and increased amounts of these structures in the cell periphery. An increase in MT tyrosination and a decrease in MT acetylation, which demonstrated MT destabilization, were also found. Moreover, MC-LR-induced hyperphosphorylation of the neural microtubule-associated protein tau, which correlated with an increase in soluble tau and a decrease in cytoskeleton-associated tau. Besides, the phosphorylation of the actin-associated protein HSP27 was also increased in MC-LR-treated cells. Furthermore, MC-LR caused a concentration-dependent decrease in the activity of protein phosphatase 2A (PP2A), and a dramatic activation of p38 mitogen-activated protein kinase (MAPK). The dephosphorylated tau dissociated from PP2A, whereas the tau phosphorylation status paralleled the activation of p38 MAPK. Pretreatment with the p38 MAPK inhibitor SB203580 effectively abolished hyperphosphorylation of tau and HSP27, and blocked MC-LR-triggered cytoskeletal alterations. Taken together, MC-LR leads to the reorganization of cytoskeletal architectures in PC12 cells and hyperphosphorylation of tau and HSP27, which may be caused by direct PP2A inhibition and indirect p38 MAPK activation.     

Microcystin‐LR‐Caused ROS generation involved in p38 activation and tau hyperphosphorylation in neuroendocrine (PC12) cells

Microcystin‐LR (MC‐LR), a potent specific hepatotoxin produced by cyanobacteria, has recently been reported to show neurotoxicity. Our previous study demonstrated that MC‐LR caused the reorganization of cytoskeleton architectures and hyperphosphorylation of the cytoskeletal‐associated proteins tau and HSP27 in neuroendocrine PC12 cell line by direct PP2A inhibition and indirect p38 mitogen‐activated protein kinase (MAPK) activation. It has been shown that oxidative stress is extensively associated with MC‐LR toxicity, mainly resulting from an excessive production of reactive oxygen species (ROS). However, the mechanisms by which ROS mediates the cytotoxic action of MC‐LR are unclear. In the present study, we investigated whether ROS might play a critical role in MC‐LR‐induced hyperphosphorylation of microtubule‐associated protein tau and the activation of the MAPKs in PC12 cell line. The results showed that MC‐LR had time‐ and concentration‐dependent effects on ROS generation, p38‐MAPK activation and tau phosphorylation. The time‐course studies indicated similar biphasic changes in ROS generation and tau hyperphosphorylation, which started to increase within 1 h and reached the maximum level at 3 h followed by a decrease after prolonged treatment. Furthermore, pretreatment with the antioxidants, N‐acetylcysteine and vitamin C, significantly decreased MC‐LR‐induced ROS generation and effectively attenuated p38‐MAPK activation as well as tau hyperphosphorylation. Taken together, these findings suggest that ROS generation triggered by MC‐LR is a key intracellular event that contributes to an induction of p38‐MAPK activation and tau phosphorylation, and that blockade of this ROS‐mediated redox‐sensitive signal cascades may attenuate the toxic effects of MC‐LR. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 366–374, 2015.     

Effects of sodium ferulate on amyloid-beta-induced MKK3/MKK6-p38 MAPK-Hsp27 signal pathway and apoptosis in rat hippocampus

AIM: To observe the effects of sodium ferulate (SF) on amyloid beta (Abeta)1-40-induced p38 mitogen-activated protein kinase (MAPK) signal transduction pathway and the neuroprotective effects of SF. METHODS: Rats were injected intracerebroventricularly with Abeta1-40. Six hours after injection, Western blotting was used to determine the expressions of phosphorylated mitogen-activated protein kinase kinase (MKK) 3/MKK6, phospho-p38 MAPK, interleukin (IL)-1beta, phospho-MAPK activating protein kinase 2 (MAPKAPK-2), the 27 kDa heat shock protein (Hsp27), procaspase-9, -3, and -7 cleavage, and poly (ADP-ribose) polymerase (PARP) cleavage. Seven days after injection, Nissl staining was used to observe the morphological change in hippocampal CA1 regions. RESULTS: Intracerebroventricular injection of Abeta1-40 induced an increase in phosphorylated MKK3/MKK6 and p38 MAPK expressions in hippocampal tissue. These increases, in combination with enhanced interleukin (IL)-1beta protein expression and reduced phospho-MAPKAPK2 and phospho-Hsp27 expression, mediate the Abeta-induced activation of cell death events as assessed by cleavage of procaspase-9, -3, and -7 and caspase-3 substrate PARP cleavage. Pretreatment with SF (100 mg/kg and 200 mg/kg daily, 3 weeks) significantly prevented Abeta1-40-induced increases in phosphorylated MKK3/MKK6 and p38 MAPK expression. The Abeta1-40-induced increase in IL-1beta protein level was attenuated by pretreatment with SF. In addition, Abeta1-40-induced decreases in phosphorylated MAPKAPK2 and Hsp27 expression were abrogated by administration of SF. In parallel with these findings, Abeta1-40-induced changes in activation of caspase-9, caspase-7, and caspase-3 were inhibited by pretreatment with SF. CONCLUSION: SF prevents Abeta1-40-induced neurotoxicity through suppression of MKK3/MKK6-p38 MAPK activity and IL-1beta expression and upregulation of phospho-Hsp27 expression.