Phenolic compounds from <Emphasis Type="Italic">Pueraria lobata</Emphasis> protect PC12 cells against Aβ-induced toxicity

Bioassay-guided fractionation of the EtOAc-soluble extract of Pueraria lobata based on the inhibition of Aβ-induced toxicity in PC12 cells resulted in the isolation of four known active compounds, genistein (8), biochanin A (9), sissotrin (10), and puerol B (11). Of these, genistein (8) and biochanin A (9) exhibited potent neuroprotective effects with ED₅₀ values of 33.7 and 27.8 μM, respectively. In addition, a new coumestan, 2-(α,α-dimethylallyl)coumestrol (1) was isolated and characterized, but proved to be inactive, as were additional seven known compounds. The structure of new compound 1 was determined using spectroscopic techniques.     

Neuroprotection by the synthetic neurosteroid enantiomers ent-PREGS and ent-DHEAS against Aβ25–35 peptide-induced toxicity in vitro and in vivo in mice

Rationale

Pregnenolone sulfate (PREGS) and dehydroepiandrosterone sulphate (DHEAS) are pro-amnesic, anti-amnesic and neuroprotective steroids in rodents. In Alzheimer’s disease (AD) patient’s brains, their low concentrations are correlated with high levels of Aβ and tau proteins. The unnatural enantiomer ent-PREGS enhanced memory in rodents. We investigated here whether ent-PREGS and ent-DHEAS could be neuroprotective in AD models.

Objective

The effects of PREGS, ent-PREGS, DHEAS and ent-DHEAS against Aβ_25–35 peptide-induced toxicity were examined in vitro on B104 neuroblastoma cells and in vivo in mice.

Methods

B104 cells pretreated with the steroids before Aβ_25–35 were analysed by flow cytometry measuring cell viability and death processes. Mice injected intracerebroventricularly with Aβ_25–35 and the steroids were analysed for their memory abilities. Additionally, lipid peroxidation levels in the hippocampus were measured.

Results

ent-PREGS and PREGS significantly attenuated the Aβ_25–35-induced decrease in cell viability. Both steroids prevented the Aβ_25–35-induced increase in late apoptotic cells. PREGS further attenuated the ratio of necrotic cells. ent-DHEAS and DHEAS significantly reduced the Aβ_25–35-induced toxicity and prevented the cells from entering late apoptosis and necrosis. All steroids stimulated neurite outgrowth per se and prevented the Aβ_25–35-induced decrease. In vivo, ent-PREGS and ent-DHEAS significantly attenuated the Aβ_25–35-induced decrease in memory (spontaneous alternation and passive avoidance) and an increase in lipid peroxidation levels. In contrast to the natural steroids, both enantiomers prevented amnesia when injected 6 h before Aβ_25–35 in contrast to the natural steroids.

Conclusion

The unnatural steroids ent-PREGS and ent-DHEAS are potent neuroprotective agents and could be effective therapeutical tools in AD.     

Neuroprotective effect of naturally occurring RXR agonists isolated from Sophora tonkinensis Gagnep. on amyloid-β-induced cytotoxicity in PC12 cells

Journal of Natural Medicines - Neuronal cell death induced by amyloid-β (Aβ) oligomers is implicated in neuronal degeneration and is a leading cause of Alzheimer’s disease (AD)....     

Correction to: Neuroprotective effect of naturally occurring RXR agonists isolated from Sophora tonkinensis Gagnep. on amyloid-β-induced cytotoxicity in PC12 cells

Journal of Natural Medicines - In the original publication of the article, Table&nbsp;1 and Fig.&nbsp;1 were incorrectly published.     

白果内酯对抗淀粉样β-肽25-35所致PC12细胞毒作用(英文)

目的:观察白果内酯对β-淀粉样蛋白片段25-35(Aβ25-35)所致PC12细胞毒性的影响。方法:用噻唑兰(MTF)及乳酸脱氢酶法检测PC12细胞的存活率;硫代巴比妥酸法测定细胞脂质过氧化;并同时检测了细胞内抗氧化酶活性。结果:白果内酯(25-100)μmol·L~(-1)剂量依赖性地抑制Aβ25-35(100 μmol·L~(-1))引起的细胞存活率下降,脂质过氧化及抗氧化酶活性下降。结论:白果内酯具有对抗Aβ25-35引起的PC12细胞毒性的作用。     

Inhibitory effects of (1R,9S)-β-hydrastine on calcium transport in PC12 cells

(1R,9S)-beta-Hydrastine (BHS), at 100 microM, has been shown to mainly reduce the K+-induced dopamine release and Ca2+ influx by blocking the L-type Ca2+ channel and inhibit the caffeine activated store-operated Ca2+ channels, but not those activated by thapsigargin, in PC12 cells. In this study, the effects of BHS on Ca2+ transport from Ca2+ stores in the absence of external Ca2+ were investigated in PC12 cells. BHS decreased the basal intracellular Ca2+ concentration ([Ca2+]i) in the absence of external Ca2+ in PC12 cells. In the absence of external Ca2+, pretreating PC12 cells with 100 microM BHS reduced the rapid increase in the [Ca2+]i elicited by 20 mM caffeine, but not that by 1 microM thapsigargin. In addition, BHS inhibited the increase in the [Ca2+]i elicited by restoration of 2 mM CaCl2 after the Ca2+ stores had been depleted by 20 mM caffeine, but not those depleted by 1 microM thapsigargin, in the absence of external Ca2+. These results suggested that BHS mainly inhibited Ca2+ leakage from the Ca2+ stores and the caffeine-stimulated release of Ca2+ from the caffeine-sensitive Ca2+ stores in PC12 cells.     

原花青素对Aβ_(25-35)诱导PC12细胞凋亡的影响及其机制的研究

目的　探讨原花青素(Procyanidins,PC)对β淀粉样肽25~35(βamyloidpeptide25 -35, Aβ25-35 )诱导PC12细胞凋亡的影响及其机制。方法　采用MTT比色法分析细胞存活率, Hoechst33258 PI荧光染色法检测凋亡, RT PCR检测P53和bcl 2基因mRNA表达,Westernblot检测P53和Bcl 2蛋白表达。结果　不同剂量PC预处理PC12细胞 1h可剂量依赖性对抗Aβ25-35引起的凋亡,提高细胞的存活率,减少Aβ25-35引起的核固缩,凝聚和碎裂,降低P53mRNA表达以及P53蛋白表达,增加bcl 2mRNA表达以及Bcl 2蛋白表达。结论　PC可剂量依赖性对抗Aβ25-35对PC12细胞的毒性作用,其机制可能与下调凋亡基因P53和上调抗凋亡基因bcl 2表达有关。     

MCI-186对Aβ_(25-35)诱导PC12细胞氧化损伤韵神经保护作用

目的 探讨MCI-186(edaravone)对阿尔茨海默病(AD)细胞损伤的保护作用.方法 利用淀粉样β蛋白25-35(Aβ_(25-35))诱导PCI2细胞制备成AD细胞模型;采用MTT法确定Aβ_(25-35)抑制PC12细胞生长的半数抑制浓度(IC_(50))和MCF-186对AD细胞保护作用最强时的浓度;利用邻菲罗啉化学发光法测定羟自由基(.OH)含量,确定MCI-186清除.OH最强作用时的浓度.结果 Aβ_(25-35)诱导PC12细胞的IC_(50)是29.76 μmol/L,此浓度的Aβ_(25-35)对PC12细胞生长的最大抑制率发生在36 h;30 μol/L Aβ_(25-35)诱导PC12细胞36 h可以制成理想的AD细胞模型.20 μmol/L MCI-186清除.OH作用最强,即对AD细胞的保护作用最强.结论 MCI-186可以通过清除Aβ_(25-35)产生的.OH,在AD中发挥其神经细胞保护作用.     

槲皮素对Aβ_(25-35)致PC12细胞损伤的雌激素样保护作用及分子机制

目的以Aβ_(25-35)诱导PC12细胞损伤,建立阿尔茨海默病体外模型,探讨槲皮素(quercetin,Que)的雌激素样保护作用及分子机制。方法 MTT法检测细胞活力;免疫荧光染色检测雌激素受体两种亚型ERα和ERβ的表达;Western blot检测ERα、ERβ,以及p-Akt、total-Akt、p-GSK-3β、total-GSK-3β蛋白表达量的变化。结果 MTT结果显示, 20μmol·L~(-1)的Aβ_(25-35)作用PC12细胞24 h后,能明显降低细胞的存活率(P<0.01);Que(40、60、80μmol·L~(-1))组与模型组相比,能明显增加细胞的存活率(P<0.05);免疫荧光染色和Western blot结果显示,与模型组相比,Que明显提高ERα、p-Akt、p-GSK-3β蛋白表达量(P<0.01),ERβ蛋白表达虽有增加,但差异无显著性(P>0.05),而各实验组total-Akt和total-GSK-3β蛋白表达量基本无变化。当雌激素受体受到ICI182,780抑制后,PC12细胞活力及p-Akt、p-GSK-3β蛋白表达明显下降(P<0.01)。结论槲皮素对Aβ_(25-35)诱导的PC12细胞损伤具有保护作用,其雌激素样神经保护作用机制是通过ERα介导激活PI3K/Akt/GSK-3β信号通路。     

Houttuyniae Herba protects rat primary cortical cells from Aβ(25-35)-induced neurotoxicity via regulation of calcium influx and mitochondria-mediated apoptosis

Amyloid beta (Aβ) fibrils are believed to play a major role in the pathogenesis of Alzheimer's disease. Although the mechanisms underlying Aβ toxicity remain largely unknown, Aβ fibrils disrupt calcium homeostasis and generate free radicals, resulting in oxidative stress, mitochondrial dysfunction, and apoptotic cell death. Houttuyniae Herba, the aerial part of Houttuynia cordata Thunb. (Saururaceae), is a commonly used herb in traditional Asian medicine. It has been reported to have various bioactivities, including antioxidant effects. In the present study, we investigated the protective effect of standardised Houttuyniae Herba water extract (HCW) against Aβ(25-35)-induced neurotoxicity and its possible mechanisms in rat primary cortical cells. Pretreatment with HCW attenuated the cell damage caused by 8?μM Aβ(25-35) exposure, as evidenced by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a lactate dehydrogenase assay, and microtubule-associated protein 2 immunostaining. Moreover, HCW inhibited the Aβ(25-35)-induced elevation of the intracellular calcium level, reactive oxygen species overproduction, mitochondrial membrane potential disruption, and caspase 3 activation. These results indicate that HCW protects rat primary cortical neurons against Aβ(25-35)-induced toxicity via the regulation of calcium and the inhibition of mitochondria-mediated apoptosis.     

姜黄素影响Aβ_(25-35)诱导PC12细胞周期变化与细胞凋亡的可能机制

目的探讨姜黄素(curcum in,Cur)对β-淀粉样肽(25-35)[β-amyloidpeptide-(25-35),Aβ25-35]诱导体外血清饥饿培养的PC12细胞周期异常与凋亡保护作用的可能机制。方法5μmol.L-1Cur预处理同步于G0期的PC12细胞,加入终浓度为25μmol.L-1Aβ25-35处理0～20h,用RT-PCR和Western blot从mRNA及蛋白水平检测p21、CDK4、E2F1、bax的表达。结果与Aβ25-35诱导组比较,Cur保护组p21mRNA和p21蛋白的表达增加;CDK4、E2F1、baxmRNA和CDK4、Bax蛋白的表达降低。结论Cur可能通过上调p21的表达,下调CDK4、E2F1、bax的表达,对Aβ25-35诱导的PC12细胞周期异常与凋亡起保护作用。     

Evaluation of in vitro toxicity of peptide (N-acetyl-Leu-Gly-Leu-COOH)-substituted-β-cyclodextrin derivative,a novel drug carrier,in PC-12 cells

Background

Cyclodextrins (CDs) have been shown to improve physicochemical and biopharmaceutical properties of drugs when low solubility and low safety limit their use in the pharmaceutical field. Recently, a new amphiphilic peptide-substituted-β-CD, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD (hepta-(N-acetyl-LGL)-β-CD), is developed which exhibited good solubility, strong inclusion ability and an appropriate average molecular weight. However, there is limited information available about its toxic effects. This study was designed to evaluate cytotoxic effects of the hepta-(N-acetyl-LGL)-β-CD (50, 200, 400, and 800 μg/ml) on rat pheochromocytoma PC-12 cells.

Results

A significant reduction of cell viability with IC₅₀ values of 1115.0 μg/ml, 762.4 μg/ml, and 464.9 μg/ml at 6, 12, and 24 h post-treatment, respectively, as well as increased lipid peroxide levels and DNA damage were observed.

Conclusions

In conclusion, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD exhibit significant toxic properties at high concentrations, probably through induction of oxidative stress and genotoxicity.     

姜黄素对β-淀粉样肽(25-35)诱导去血清培养PC12细胞周期异常与细胞凋亡的影响

目的探讨姜黄素(Cur)对β-淀粉样肽(25-35)(βamyloid peptide-25-35,Aβ25-35)诱导体外去血清培养的PC12细胞周期异常与凋亡的影响.方法PC12细胞用常用的去血清培养使细胞同步于G0期,用MTT比色法分析细胞存活率,流式细胞仪检测分析细胞周期与凋亡,Hoechst33258荧光染色观察细胞核凋亡的形态学改变,RT-PCR和Western blot从mRNA及蛋白水平检测p21基因的变化.结果用不同终浓度(0,1.25,2.5,5,10,20 μmol·L-1)Cur预处理去血清培养的PC12细胞1 h,再用Aβ25-35处理24 h,细胞存活率增加;Aβ25-35引起的S期细胞百分率明显减少,凋亡率明显降低(P＜0.01),亚二倍体峰消失;核固缩、碎裂减少;p21 mRNA表达和P21蛋白表达增加.结论Cur可以影响Aβ25-35诱导的去血清培养PC12细胞周期分布及减少凋亡,可能与上调p21的表达有关.     

Thannilignan glucoside and 2-(β-glucopyranosyl)-3-isoxazolin-5-one derivative,two new compounds isolated from Terminalia bellirica

Journal of Natural Medicines - Two new compounds, thannilignan 9-O-β-glucoside (1) and 2-(β-glucopyranosyl)-3-isoxazolin-5-one derivative (2), and seven known compounds were isolated from...     

阿立哌唑对Aβ_(25-35)诱导的神经PC12细胞损伤的影响及机制

目的:研究阿立哌唑对Aβ淀粉样蛋白(Aβ_(25-35))诱导的神经PC12细胞损伤的影响及其机制。方法:将PC12细胞随机分为正常对照组、模型组(20μmol/L Aβ_(25-35))和阿立哌唑低、中、高浓度组(5、10、20μmol/L阿立哌唑+20μmol/L Aβ_(25-35)),加入含相应药物的培养基培养48 h,每组6个复孔。MTT法检测细胞活力(光密度值),Hoechst染色法检测细胞凋亡情况,分光光度法检测细胞中天冬氨酸特异性蛋白酶3(Caspase-3)、Caspase-9活性,Western blot法检测细胞中B淋巴细胞瘤2(Bcl-2)、Bcl-2相关X蛋白(Bax)、磷脂酰肌醇3激酶(PI3K)蛋白表达及蛋白激酶B(Akt)磷酸化水平。结果:与正常对照组比较,模型组细胞光密度值降低,凋亡率增加,Caspase-3、Caspase-9活性和Bax蛋白表达均增强,Bcl-2、PI3K蛋白表达和Akt磷酸化水平均降低(P<0.01)。与模型组比较,阿立哌唑低、中、高浓度组细胞光密度值增加,凋亡率减少,Caspase-3、Caspase-9活性减弱,Bcl-2、PI3K蛋白表达和Akt磷酸化水平均增加;阿立哌唑中、高浓度组细胞Bax蛋白表达减弱(P<0.05或P<0.01)。结论:阿立哌唑可明显抑制Aβ_(25-35)诱导的PC12细胞凋亡,其作用可能与激活PI3K/Akt信号通路有关。     

JAK2/STAT5/Bcl-xL signalling is essential for erythropoietin-mediated protection against apoptosis induced in PC12 cells by the amyloid β?peptide Aβ25–35

BACKGROUND AND PURPOSE

Erythropoietin (EPO) exerts neuroprotective actions in the CNS, including protection against apoptosis induced by the amyloid β−peptide Aβ_25–35. However, it remains unclear which signalling pathway activated by EPO is involved in this neuroprotection. Here, we have investigated whether JAK2/STAT5/Bcl-xL and ERK1/2 signalling pathways are essential for EPO-mediated protection against apoptosis induced by Aβ_25–35.

EXPERIMENTAL APPROACH

EPO was added to cultures of PC12 cells, 1 h before Aβ_25–35. For kinase inhibitor studies, AG490 and PD98059 were added to PC12 cells, 0.5 h before the addition of EPO. Transfection with siRNA was used to knockdown STAT5. Activation of JAK2/STAT5/Bcl-xL and ERK1/2 signalling pathways were investigated by Western blotting. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl-tetrazolium bromide assay and apoptosis was detected by TUNEL and acridine orange–ethidium bromide double staining.

KEY RESULTS

EPO increased phosphorylation of JAK2 and STAT5 in PC12 cells treated with Aβ_25–35. Furthermore, EPO modulated the nuclear translocation of phospho-STAT5, which increased expression of Bcl-xL and decreased levels of caspase-3. These beneficial effects were blocked by the JAK2 inhibitor, AG490 or STAT5 knockdown. However, the ERK1/2 pathway did not play a crucial role in our model.

CONCLUSIONS AND IMPLICATIONS

EPO protected PC12 cells against Aβ_25–35-induced neurotoxicity. Activation of JAK2/STAT5/Bcl-xL pathway was important in EPO-mediated neuroprotection. EPO may serve as a novel protective agent against Aβ_25–35-induced cytotoxicity in, for instance, Alzheimer''s disease.     

姜黄素对Aβ25-35诱导去血清培养PC12细胞p53、p21基因表达的影响

目的：在β-淀粉样肽（25—35）[βamyloid peptide-（25—35），Aβ25—35]诱导去血清培养PC12细胞周期异常模型的基础上．研究姜黄素（Curcumin，Cur）对Ap25-35诱导体外去血清培养的PC12细胞p53、p21基因表达的影响；方法：种入培养瓶的PC12细胞贴壁后用常用的去血清培养法使细胞同步于G0期，每次实验分对照组（0）、诱导组和保护组，通过RT—PCR和Western blot从mRNA及蛋白水平检测p53、p2l基因表达水平的变化.结果用5μmol／LCur预处理细胞1h，再加入终浓度为25μmol／L Aβ25-35处理0～20h，与Aβ25-35诱导组比较，     

The syntheses and characterization 3β-(4-fluorobenzoyloxy)tropane (fluorotropacocaine) and its 3α isomer

3β‐(4‐Fluorobenzoyloxy)tropane (3β‐FBT, fluorotropacocaine) was first reported by Finnish authorities to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) via the Early Warning System (EWS) in 2008 and our own laboratory tentatively identified it in 2010 in several products purchased from head shops. Very little is known about this cocaine‐like drug and, as no reference standards were available, we have synthesized and characterized both 3β‐FBT and its 3α isomer for use as reference standards. The two compounds are separable by gas chromatography (GC) but their electron‐impact (EI) mass spectra were found to be almost identical. ¹⁹F NMR spectroscopy was also found to be a useful technique for distinguishing the two isomers. Copyright © 2011 John Wiley & Sons, Ltd.     

Anti-inflammatory effect of tricin 4′-O-(threo-β-guaiacylglyceryl) ether,a novel flavonolignan compound isolated from Njavara on in RAW264.7 cells and in ear mice edema

Although recent study has shown tricin 4′-O-(threo-β-guaiacylglyceryl) ether (TTGE), an isolated compound from Njavara rice, to have the most potent anti-inflammatory effects, the action mechanism has not been fully understood. Here, we examined the effect of TTGE on the inflammation and elucidated the potential mechanism. We demonstrated that TTGE significantly inhibited LPS-induced NO and ROS generation in RAW264.7 cells, which was correlated with the down-regulating effect of TTGE on the iNOS and COX-2 expression via NF-κB and STAT3. TPA-induced ear edema was also efficiently inhibited by the TTGE treatment. TTGE blocked the induction of iNOS and COX-2 through the regulation of NF-κB and STAT3, which could explain the reduced TPA-induced edema symptoms. Moreover, the introduction of ERK inhibitor abrogated the anti-inflammatory effect of TTGE via the recovery of NF-κB and STAT3 signalings. Taken together, these results suggest that TTGE has anti-inflammatory properties through down-regulation of NF-κB and STAT3 pathways.