Viability Of PC12 Cells Research Articles

Notoginsenoside R1 alleviates lipopolysaccharide-triggered PC-12 inflammatory damage via elevating microRNA-132

Background Delayed inflammatory response is closely associated with the severity of Spinal cord injury (SCI). Herein, the function and molecular mechanism of notoginsenoside R1 (NGR1) in the in vitro model of SCI inflammation injury were explored. Methods PC-12 neuronal cells were subjected with LPS to construct a cell-based model of SCI inflammatory injury. NGR1 was applied in this cell model. miR-132 was silenced by transfection with miR-132 inhibitor. Cell viability and apoptosis were assessed, respectively. Then, the expression changes of pro-inflammatory cytokines and JNK pathway were examined. Results In this model, LPS was neurotoxic, with inhibiting PC-12 cell viability, inducing apoptosis, and enhancing concentrations of IL-6, IL-8 and TNF-α. However, NGR1 weakened the influence of LPS on PC-12 cells via elevating cell viability, decreasing apoptosis, decreasing pro-inflammatory cytokines expression, and suppressing activation of JNK signalling pathway. miR-132 was up-regulated by NGR1 treatment. Silence of miR-132 eliminated the influence of NGR1 on LPS-stimulated PC-12 cells. Conclusion NGR1 relieved PC-12 cells from LPS-triggered inflammatory damage via elevating miR-132 and hereafter suppressing JNK pathway.

Antiepileptic Effects of Protein-Rich Extract from Bombyx batryticatus on Mice and Its Protective Effects against H2O2-Induced Oxidative Damage in PC12 Cells via Regulating PI3K/Akt Signaling Pathways.

Bombyx batryticatus is a known traditional Chinese medicine (TCM) utilized to treat convulsions, epilepsy, cough, asthma, headaches, and purpura in China for thousands of years. This study is aimed at investigating the antiepileptic effects of protein-rich extracts from Bombyx batryticatus (BBPs) on seizure in mice and exploring the protective effects of BBPs against H2O2-induced oxidative stress in PC12 cells and their underlying mechanisms. Maximal electroshock-induced seizure (MES) and pentylenetetrazole- (PTZ-) induced seizure in mice and the histological analysis were carried out to evaluate the antiepileptic effects of BBPs. The cell viability of PC12 cells stimulated by H2O2 was determined by MTT assay. The apoptosis and ROS levels of H2O2-stimulated PC12 cells were determined by flow cytometry analysis. Furthermore, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), lactate dehydrogenase (LDH), and glutathione (GSH) in PC12 cells were assayed by ELISA and expressions of caspase-3, caspase-9, Bax, Bcl-2, PI3K, Akt, and p-Akt were evaluated by Western blotting and quantitative real-time polymerase chain reaction (RT-qPCR) assays. The results revealed that BBPs exerted significant antiepileptic effects on mice. In addition, BBPs increased the cell viability of H2O2-stimulated PC12 cells and reduced apoptotic cells and ROS levels in H2O2-stimulated PC12 cells. By BBPs treatments, the levels of MDA and LDH were reduced and the levels of SOD and GSH-Px were increased in H2O2-stimulated PC12 cells. Moreover, BBPs upregulated the expressions of PI3K, Akt, p-Akt, and Bcl-2, whereas they downregulated the expressions of caspase-9, caspase-3, and Bax in H2O2-stimulated PC12 cells. These findings suggested that BBPs possessed potential antiepileptic effects on MES and PTZ-induced seizure in mice and protective effects on H2O2-induced oxidative stress in PC12 cells by exerting antioxidative and antiapoptotic effects via PI3K/Akt signaling pathways.

Quercetin protects PC-12 cells against hypoxia injury by down-regulation of miR-122.

Objective(s):Impairment of nerve cells of brain induced by hypoxia results in energy-deprivation and dysfunction, which accompanies with neurons apoptosis. Improving function of nerve cells is important for treating cerebral anoxia. This study aimed to investigate the role of Quercetin (Quer) in hypoxia-induced injury of pheochromocytoma (PC-12) cells. Materials and Methods:PC-12 cells were cultured under anoxic condition for induction of hypoxia injury and/or treatment with Quer, transfection with pre-miR-122, anti-miR-122 or their negative controls. After Quer treatment, viability, migration, and cell apoptosis of PC-12 cells were analyzed by CCK-8 assay, transwell assay and flowcytometry analysis, respectively. Cell proliferation-associated proteins and cell apoptosis-associated proteins were analyzed by Western blot. Relative miR-122 expression in Quer-treated cells or transfection efficacy of miR-122 was analyzed by qRT-PCR. Finally, main components in AMP-activated protein kinase (AMPK) and Wnt/β-catenin signaling pathways were analyzed by Western blot.Results:Quer alleviated hypoxia-induced injury in PC-12 cells by increasing viability, promoting cell proliferation, enhancing migration and repressing apoptosis. Also, miR-122 was down-regulated in Quer-treated cells. miR-122 overexpression decreased cell viability and migration, and increased cell apoptosis in hypoxia- treated PC-12 cells, but miR-122 silencing led to the opposite results. We also found that AMPK and Wnt/β-catenin signaling pathways were activated by Quer in hypoxia-induced injury, but were inactivated in hypoxia-induced cells by overexpression of miR-122.Conclusion:Quer could repress hypoxia-induced injury in PC-12 cells by activating AMPK and Wnt/β-catenin signaling pathways via down-regulation of miR-122.

Citicoline protects against lead-induced oxidative injury in neuronal PC12 cells.

Lead is a major environmental pollutant that causes serious adverse effects on biological systems and cells. In this study, we examined the effect of citicoline on lead-induced apoptosis in PC12 cells. The PC12 cells were pre-treated with citicoline and then exposed to lead for 48 h. The effect of citicoline on cell survival was examined by MTT assay. In addition, levels of lipid peroxidation (LPO), total thiol groups, total antioxidant power (TAP), catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) were evaluated. The levels of Bax, Bcl-2, and caspase-3 were also measured, by Western blot analysis. Citicoline significantly increased the cell viability of PC12 cells exposed to lead. Treatment of PC12 cells with lead increased LPO levels, and citicoline effectively decreased LPO. Levels of total thiol groups and TAP, CAT, SOD, and GSH were significantly increased in citicoline-treated PC12 cells compared with the lead-treated group. Citicoline pretreatment significantly reduced Bax expression, and increased the level of Bcl-2 expression. Citicoline also reduced caspase-3 activation in PC12 cells compared with the lead-treated group. Our findings indicate that citicoline exerts a neuroprotective effect against lead-induced injury in PC12 cells through mitigation of oxidative stress and, at least in part, through suppression of the mitochondria-mediated apoptotic pathway.

The antidepressant effects of hesperidin on chronic unpredictable mild stress-induced mice

Hesperidin, a kind of citrus bioflavonoid distributed in foods including grapefruits, oranges and lemons, has many pharmacological activities. This study was aimed to evaluate the anti-depressant-like effect of hesperidin on chronic unpredictable mild stress (CUMS)-induced mice. Depressive-like behavior was detected by the sucrose preference test (SPT), tail suspension test (TST) and forced swimming test (FST). A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to assess the cell viability of corticosterone-induced PC12 cells. The serum, hippocampal and cell supernatant concentrations of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α were determined using enzyme-linked immunosorbent assay (ELISA) commercial kits. Furthermore, the protein expression levels of high-mobility group box 1 protein (HMGB1), receptor for advanced glycation end-products (RAGE)/NF-κB and brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway in the hippocampus and corticosterone-induced PC12 cells were detected by Western blot. Our results showed that hesperidin (100, 200 mg/kg) significantly relieved depressive-like behaviors, including decreased sucrose consumption in sucrose preference test (SPT), immobility in the forced swimming test (FST), tail suspension test, and locomotor activity in the open field test (OFT). Hesperidin reduced inflammatory cytokine levels by attenuating the HMGB1/RAGE/NF-κB signaling pathway and BDNF/TrkB pathway both in vivo and in vitro. In conclusion, hesperidin possessed efficient neuroprotective effects on depression, which was associated with neuroinflammation mediated by the HMGB1/RAGE/NF-κB and BDNF/TrkB pathways.

25C-NBOMe, a Novel Designer Psychedelic, Induces Neurotoxicity 50 Times More Potent Than Methamphetamine In Vitro.

25C-NBOMe is a designer substituted phenethylamine and a high-potency psychedelic that acts on the 5-HT2A receptor. Although 25C-NBOMe overdoses have been related to several deaths in the USA and Europe, very limited data exists on the in vitro neurotoxicity of 25C-NBOMe. In this study, we found that 25C-NBOMe potently reduced cell viability of SH-SY5Y, PC12, and SN4741 cells, with IC50 values of 89, 78, and 62μM, respectively. Methamphetamine decreased the cell viability of these cells with IC50 values at millimolar range in the same tests, indicating that 25C-NBOMe is > 50 times more potent than methamphetamine in its ability to reduce viability of SH-SY5Y cells. The neurotoxicity of 25C-NBOMe on SH-SY5Y cells was further confirmed by using fluorescein diacetate/propidium iodide double staining. 25C-NBOMe elevated the expression of phosphorylated extracellular signal-regulated kinase (pERK), but decreased the expression of phosphorylated Akt and phosphorylated Ser9- glycogen synthase kinase 3β (GSK3β) in time- and concentration-dependent manners. Interestingly, either specific GSK3β inhibitors or specific mitogen-activated protein kinase kinase (MEK) inhibitors significantly prevented 25C-NBOMe-induced neurotoxicity in SH-SY5Y cells. These results suggest that 25C-NBOMe unexpectedly produced more potent neurotoxicity than methamphetamine and that the inhibition of the Akt pathway and activation of the ERK cascade might be involved in 25C-NBOMe-induced neurotoxicity. Most importantly, these findings further inform the toxicity of 25C-NBOMe abuse to the central nervous system for public health.

Luteolin protects PC-12 cells from H2O2-induced injury by up-regulation of microRNA-21

BackgroundIschemic cerebrovascular disease (ICVD) is the third leading cause of death worldwide. Luteolin is a naturally flavonoid widely distributed in many plant leaves. This study aimed to explore the effects of luteolin on H2O2-induced ICVD cell oxidative injury model, as well as underlying molecular mechanisms. MethodsViability and apoptosis of PC-12 cells and rat brain microvascular endothelial cells (rBMECs) were detected using CCK-8 assay and FITC-Annexin V/PI staining, respectively. The levels of ROS and MDA were measured using DCFH-DA staining and MDA assay kit, respectively. Cell transfection was conducted to change the expression level of miR-21. Expression levels of key factors involved in cell proliferation, oxidative stress, apoptosis, PI3K/AKT and PDCD4/p21 pathways were evaluated using western blotting. ResultsLow concentration of luteolin had no significant effect on PC-12 cell viability and presented protective effects on H2O2-induced PC-12 cell viability loss, proliferation inhibition, ROS generation, oxidative stress increase and apoptosis. Moreover, luteolin up-regulated the expression level of miR-21 in H2O2-treated PC-12 cells. Overexpression of miR-21 strengthened the protective effects of luteolin on H2O2-induced PC-12 cell oxidative injury. Suppression of miR-21 had opposite effects. Furthermore, luteolin alleviated H2O2-induced inactivation of PI3K/AKT pathway and activation of PDCD4/p21 pathway in PC-12 cells by up-regulating miR-21. Besides, luteolin also protected rBMECs from H2O2-induced oxidative injury. ConclusionOur research revealed the protective effects of luteolin on H2O2-induced ICVD cell oxidative injury. Luteolin protected PC-12 cells from H2O2-induced oxidative injury by up-regulating miR-21, activating PI3K/AKT pathway and inactivating PDCD4/p21 pathway.

Nrf2 mediates the protective effect of edaravone after chlorpyrifos-induced nervous system toxicity.

We aim to confirm the impairment of chlorpyrifos (CPF) in PC12 cells, evaluate the protective effect of edaravone on CPF-induced injury, and try to unravel its underlying mechanism perspective from Nrf2 signaling pathway. Viability of PC12 cells treated with CPF and edaravone (Ed) were evaluated by MTT assay. Cell apoptosis was observed by the Hoechst 33342 stain. The level of reactive oxygen species (ROS), the content of malondialdehyde (MDA), and the activity of superoxide dismutase (SOD) were detected to evaluate the oxidative stress injury. The expression of Nrf2 was detected by Western blot; profoundly, RNA interference was conducted to construct Nrf2 gene knockdown PC12 cells and to uncover its underlying mechanism. MTT results showed CPF injured PC12 cells in a concentration-dependent manner. Increased ROS and MDA content, decreased total SOD activity, or even apoptosis were occurred in PC12 cells when treated with CPF. Interestingly, CPF-induced cell injury was conspicuously reversed after Ed administration. Nrf2 signaling pathway was activated after Ed treatment and the neuroprotective effect of Ed was not significant in cells after Nrf2 gene knockdown. In conclusion, Ed exerts neuroprotective effect on CPF-induced oxidative stress injury and its mechanism was correlated with the Nrf2 signaling pathway.

Protective effect of ethyl vanillin against Aβ-induced neurotoxicity in PC12 cells via the reduction of oxidative stress and apoptosis.

Increased aggregation of β-amyloid (Aβ) peptides induces oxidative stress, which is considered a major contributor in the development of Alzheimer's disease (AD). Prevention of Aβ-induced neurotoxicity is proposed as a possible modality for treatment of AD. The present study aimed to elucidate possible effects of ethyl vanillin (EVA), an analog of vanillin isolated from vanilla beans, on the Aβ1-42-induced oxidative injury in PC12 cells. EVA restrained the decrease in PC12 cell viability and apoptosis induction caused by treatment with Aβ1-42. In addition, EVA markedly alleviated intracellular lipid peroxidation as demonstrated by malondialdehyde levels and reactive oxygen species production in Aβ1-42-treated PC12 cells. In addition, the reduction in the activity levels of the antioxidative enzymes superoxide dismutase, catalase and glutathione peroxidase was detected in Aβ1-42-treated PC12 cells. This effect was partially reversed by treatment with EVA. Furthermore, the results indicated that EVA attenuated Aβ1-42-induced caspase-3 activation and the increase noted in the apoptosis regulator Bcl-2/apoptosis regulator Bax ratio of PC12 cells. These results indicated that EVA could be used as an efficient and novel agent for the prevention of neurodegenerative diseases via inhibition of oxidative stress and cell apoptosis.

Protective Role of SOCS3 Modified Bone Marrow Mesenchymal Stem Cells in Hypoxia-Induced Injury of PC12 Cells

We attempted to explore the possible effects of SOCS3 (suppressor of cytokine signaling 3)-modified bone marrow mesenchymal stem cells (BMSCs) on the hypoxic injury of rat adrenal gland pheochromocytoma (PC-12) cells. PC12 cells were cultured with EGFP (enhanced green fluorescent protein)-BMSCs and SOCS3-BMSCs respectively under hypoxia in vitro and classified into control, hypoxia, EGFP-BMSCs, and SOCS3-BMSC groups. CCK-8, Hoechst 33258 staining, and Annexin V-FITC/PI staining were assessed to measure the viability and apoptosis of hypoxia-induced PC12 cells. The JAK/STAT3 pathway- and apoptosis-related proteins were identified by Western blot. Finally, rat models of permanent middle cerebral artery occlusion (pMCAO) were established to verify the potential influences of SOCS3-BMSCs in vivo. SOCS3-modified BMSCs can stably express SOCS3 protein. EGFP-BMSCs, especially SOCS3-BMSCs, can improve cell viability and SOD content, and reduce cell apoptosis, LDH viability, and MDA content in hypoxia-induced PC12 cells (all P < 0.05). Besides, EGFP-BMSCs and SOCS3-BMSCs decreased cleaved caspase-3 level and increased Bcl-2/Bax of hypoxia-induced PC12 cells, while SOCS3-BMSCs could also elevate SOCS3 protein and reduce p-STAT3 protein level in hypoxia-induced PC12 cells (all P < 0.05). In vivo experiments confirmed that EGFP-BMSCs, particularly SOCS3-BMSCs, could ameliorate infarct size and inhibit neuronal apoptosis of different degrees in pMACO rats (all P < 0.05). SOCS3-modified BMSCs can alleviate oxidative stress, improve cell viability, and reduce neuronal apoptosis by downregulation of JAK/STAT3 pathway, thereby exerting the neuroprotective role in ischemic brain injury.

ESE1 expression correlates with neuronal apoptosis in the hippocampus after cerebral ischemia/reperfusion injury.

Epithelial-specific ETS-1 (ESE1), a member of the ETS transcription factor family, is widely expressed in multiple tissues and performs various functions in inflammation. During neuroinflammation, ESE1 promotes neuronal apoptosis; however, the expression and biological functions of ESE1 remain unclear after cerebral ischemia/reperfusion. We performed in vivo and in vitro experiments to explore the role of ESE1 in cerebral ischemic injury. A modified four vessel occlusion method was used in adult Sprague-Dawley rats. At 6, 12, 24, 48, and 72 hours after model induction, the hippocampus was collected for analysis. Western blot assays and immunohistochemistry showed that the expression of ESE1, phosphorylated p65 and active caspase-3 was significantly up-regulated after ischemia. Double immunofluorescence staining indicated that ESE1 and NeuN were mostly co-located in the hippocampus after ischemia. Furthermore, ESE1 was also co-expressed with active caspase-3. PC12 cells were stimulated with cobalt chloride (CoCl2) to establish a chemical hypoxia model. After ESE1 knockdown by siRNA for 6 hours, cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assays. The levels of ESE1, phosphorylated p65 and active caspase-3 were also remarkably increased in PC12 cells after CoCl2 stimulation. After ESE1 knockdown, PC12 cell viability was increased after hypoxia. siRNA knockdown of ESE1 decreased the level of p-p65 and active caspase-3 after CoCl2 stimulation. These data reveal that ESE1 levels are elevated in the hippocampus after cerebral ischemia/reperfusion injury. This may play a role in neuronal apoptosis via activation of the nuclear factor-κB pathway.

Green tea polyphenols protect PC12 cells against H2O2-induced damages by upregulating lncRNA MALAT1.

It is of significance to alleviate oxidative damages for the treatment of spinal cord injury (SCI). Studies have ascertained that green tea polyphenols (GTPs) exert protective activities against oxidative damages. In this study, we aimed to investigate the protective effects of GTP against H2O2-caused injuries in PC12 cells as well as the molecular underpinnings associated with long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). PC12 cells were preincubated with GTP prior to H2O2 stimulation. Furthermore, MALAT1-deficient PC12 cells were constructed by transfection and identified by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Next, viability and apoptosis were detected by cell counting kit-8 and flow cytometry, respectively. Meanwhile, Western blot assay was carried out to monitor the expression alteration of proteins associated with apoptosis (Bcl-2, Bax, pro-Caspase-3/9, and cleaved Caspase-3/9) and autophagy (microtubule-associated protein 1 light chain 3 (LC3)-II, LC3-I, Beclin-1, and p62). Moreover, we examined the expression of β-catenin and dissected the phosphorylation of phosphatidylinositol 3′-kinase (PI3K) and protein kinase B (AKT). We found that H2O2 decreased the viability of PC12 cells while initiated apoptosis and autophagy processes. GTP-preincubated PC12 cells maintained the viability and resisted the apoptosis and autophagy induced by H2O2. Pointedly, GTP-pretreated PC12 cells showed an increase in MALAT1 after H2O2 stimulation. Of note, the protective effects of GTP were buffered in MALAT1-deficient cells in response to H2O2. The expression of β-catenin and phosphorylation of PI3K and AKT were upregulated by GTP, while MALAT1 knockdown led to opposite results. To sum up, GTP protected PC12 cells from H2O2-induced damages by the upregulation of MALAT1. This process might be through activating Wnt/β-catenin and PI3K/AKT signal pathways.

Fe3+ Facilitates Endocytic Internalization of Extracellular Aβ1-42 and Enhances Aβ1-42-Induced Caspase-3/Caspase-4 Activation and Neuronal Cell Death.

Amyloid β (Aβ) peptide is a critical causative factor in Alzheimer's disease (AD) and of a variety of fragmented Aβ peptides Aβ1-42 thought to exhibit the most neurotoxic effect. The present study investigated the effects of Fe3+ on Aβ1-42 internalization and Aβ1-42-induced caspase activation and neurotoxicity using mouse hippocampal slices and cultured PC-12 cells. Extracellularly applied Aβ1-42 increased the cell-associated Aβ1-42 levels in a concentration-dependent manner, and the effect was enhanced by adding Fe3+. Fe3+-induced enhancement of the cell-associated Aβ1-42 levels was significantly inhibited by the endocytosis inhibitors dynasore and methyl-β-cyclodextrin. Aβ1-42 reduced PC-12 cell viability in a concentration-dependent manner, and further reduction of the cell viability was obtained with Fe3+. Aβ1-42-induced reduction of cell viability was not affected by A187, an antagonist of amylin-3 receptor. Aβ1-42 activated caspase-3, caspase-4, and caspase-8 to a variety of degrees and Fe3+ further enhanced Aβ1-42-induced activation of caspase-3 and caspase-4. Taken together, these results indicate that Fe3+ accelerates endocytic internalization of extracellular Aβ1-42, enhances Aβ1-42-induced caspase-3/caspase-4 activation, and promotes Aβ1-42-induced neuronal cell death, regardless of amylin receptor.

Inhibition of ROS-mediated activation Src-MAPK/AKT signaling by orientin alleviates H2O2-induced apoptosis in PC12 cells.

PurposeReactive oxygen species (ROS) are considered a direct cause of neurodegenerative diseases (NDDs). Drugs developed to target ROS are effective for the treatment of NDDs. Orientin is a pyrone glucoside extracted from Polygonum orientale, and it exhibits many pharmacological activities. In this study, we aimed to determine whether orientin could relieve hydrogen peroxide (H2O2)-induced neuronal apoptosis and to investigate the specific target of orientin.Materials and methodsIn this study, the neuroprotective effect and its possible mechanisms of orientin in mouse pheochromocytoma cell line (PC12) cells stimulated by H2O2, establishing an oxidative stress model, were investigated. And we further tested the role of ROS in the neuroprotective effects of orientin.ResultsOrientin (5–100 µg/mL) did not cause toxicity in PC12 cells but significantly decreased H2O2-induced reduction in PC12 cell viability, cell apoptosis rates, and nuclear condensation. It also inhibited the activation of caspase-3 and degradation of poly(ADP-ribose) polymerase (PARP). Under the stimulation of H2O2, MAPKs (ERK, JNK, and p38), AKT, and Src signaling proteins in PC12 cells were activated in a time-dependent manner. The application of inhibitors that were specific for MAPKs, AKT, and Src effectively alleviated H2O2-induced cell apoptosis. In addition, the Src inhibitor decreased the activation of MAPKs and AKT signaling. More importantly, orientin effectively decreased H2O2-induced phosphorylation of MAPKs, AKT, and Src signaling proteins. Finally, we confirmed that orientin effectively inhibited H2O2-induced accumulation of ROS in cells. In addition, ROS inhibitors blocked the Src-MAPKs/AKT signaling pathway-dependent cell apoptosis stimulated by H2O2.ConclusionThese results indicate that alleviation of H2O2-induced cell apoptosis by orientin is Src-MAPKs/AKT dependent. Overall, our study confirms that orientin alleviates H2O2-induced cell apoptosis by inhibiting the ROS-mediated activation of Src-MAPKs/AKT signaling.

Morphine reverses the effects of 1-methyl-4-phenylpyridinium in PC12 cells through activating PI3K/Akt

Aim of the study: Parkinson’s disease (PD) is a neurodegenerative disorder. It is caused by the degeneration of dopaminergic neurons and the dopamine (DA) deletion in the substantia nigra pars compacta (SNpc). Morphine elevates the level of dopamine in the mesolimbic dopamine system and plays a role in alleviating PD symptoms. However, the molecular mechanism is still unclear. The aim of the study is to investigate the mechanism on morphine alleviating PD symptoms.Materials and methods: The viability of PC12 cells was measured by using MTT assay. The expressions of tyrosine hydroxylase (TH), thioredoxin-1 (Trx-1), CyclinD1 and Cyclin-dependent kinase5 (Cdk5) were detected by Western Blot.Results: In present study, we found that morphine increased the cell viability in PC12 cells. 1-methyl-4-phenylpyridi-nium (MPP+) reduced the cell viability and TH expression, which were reversed by morphine. MPP+ decreased the expressions of Trx-1, CyclinD1, Cdk5, which were restored by morphine. Moreover, the role of morphine in restoring the expressions of Trx-1, CyclinD1 and Cdk5 decreased by MPP+ was abolished by LY294002, phosphatidylinositol-3-kinase (PI3K)/Akt inhibitor.Conclusions: These results suggest that morphine reverses effects induced by MPP þ through activating PI3K/Akt pathway.

Synthesis and biological evaluation of genistein-O-alkylamine derivatives as potential multifunctional anti-Alzheimer agents.

A series of genistein derivatives were synthesized and evaluated as multifunctional anti-Alzheimer agents. The results showed that these derivatives had significant acetylcholinesterase (AChE) inhibitory activity; compound 5a exhibited the strongest inhibition to AChE with an IC50 value (0.034μM) much lower than that of rivastigmine (6.53μM). A Lineweaver-Burk plot and molecular modeling study showed that compound 5a targeted both the catalytic active site and the peripheral anionic site of AChE. These compounds also showed potent peroxy scavenging activity and metal-chelating ability. The compounds did not show obvious effect on HepG2 and PC12 cell viability at the concentration of 100μM. Therefore, these genistein derivatives can be utilized as multifunctional agents for the treatment of AD.

A comparative study on the shape-dependent biological activity of nanostructured zinc oxide

Monitoring and stimulating in biological systems are strongly dependent on the nature of the interfaces between biological systems and devices; in addition, one-dimensional nanostructures show high-charge accumulation at their surfaces which result in forming a conductive pathway between devices and cells. ZnO nanostructures because of their dual semiconducting properties and their piezoelectricity show a great potential to deploy in optoelectronic devices, biosensors and transducers in biological systems. For this purpose, we introduced a novel one-step hydrothermal nanowire array fabrication and compared it with ZnO nanorods array and ZnO compact film. Grazing incidence X-ray Diffraction (GIXRD), field-emission scanning electron microscope (FE-SEM), disperse X-ray spectroscopy (EDS) detector and inductively couples plasma optical emission spectrometry (ICP-OES) were used for physical and chemical characterizations of the arrays. In addition, we investigated the ability of zinc oxide nanostructures to control cell adhesion and viability of neuron-like PC12 cells. Furthermore, we examined the zinc oxide solubility and our results indicated that cytotoxicity were occurred in 2.23 ± 0.41 µg/ml concentration of zinc ions which was much less than the safe amount of zinc ions (10.23 ± 0.41 µg/ml) reported in previous studies. It is believed that ZnO dissociation behavior crucially affects cell fates even in rare amounts.

RETRACTED: Angelica polysaccharide protects PC-12 cells from lipopolysaccharide-induced injury via down-regulating microRNA-223.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concerns were initially raised regarding the Western Blots from Figures 1C, 1G, 2B, 2D, 4D, 4F, 5 (left panel), 6C and 6E. Given also the comments of Dr Elisabeth Bik regarding this article “… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated”, the journal requested the authors to provide the raw data. The authors have not provided raw data of sufficient quality and detail to support the authors’™ claim and therefore the Editor-in-Chief decided to retract the article.

Interaction of silica nanoparticles with tau proteins and PC12 cells: Colloidal stability, thermodynamic, docking, and cellular studies

Study on the side effects of the nanoparticles (NPs) can provide useful information regarding their biological and medical applications. Herein, the colloidal stability of the silicon dioxide NPs (SiO2 NPs) in the absence and presence of tau was investigated by TEM and DLS techniques. Afterwards, the thermodynamic parameters of interaction between SiO2 NPs and tau were determined by fluorescence spectroscopy and docking studies. Finally, the cytotoxic effects of SiO2 NPs on the viability of PC12 cells were investigated by MTT, AO/EB staining and flow cytometry assays. TEM, DLS, and zeta potential investigations revealed that tau can reduce the colloidal stability of SiO2 NPs. Fluorescence spectroscopy study indicated that SiO2 NPs bound to the tau with high affinity through hydrogen bonds and van der Waals interactions. Docking study also determined that Ser, Thr and Tyr residues provide a polar microenvironment for SiO2 NPs/tau interaction. Cellular studies demonstrated that SiO2 NPs can induce cell mortality through both apoptosis and necrosis mechanisms. Therefore, it may be concluded that the biological systems such as nervous system proteins can affect the colloidal stability of NPs and vice versa NPs in the biological systems can bind to proteins and cell membranes non-specifically and may induce toxicity.

GLP-1 receptor regulates cell growth through regulating IDE expression level in Aβ1-42-treated PC12 cells.

This study aimed to validate whether glucagon-like peptide-1 receptor (GLP-1R) / cyclic adenosine monophosphate (cAMP) / protein kinase (PKA) / insulin-degrading enzyme (IDE) signaling pathway was associated with neuronal apoptosis. We developed an animal model presenting both Alzheimer’s disease (AD) and type 2 diabetes (T2D), by crossing APP/PS1 mice (AD model) with streptozotocin (STZ)-treated mice (a T2D model). Neuronal apoptosis was detected by TUNEL staining and the expression levels of apoptosis-related proteins were examined by Western blotting. The viability of PC12 cells was analyzed by MTT assay and apoptosis of PC12 cells was detected by flow cytometry. The mRNA expression level was detected by qRT-PCR. T2D contributes to AD progress by prompting neuronal apoptosis and increasing expression of pro-apoptotic protein. β-Amyloid peptide1–42 (Aβ1–42) was shown to exert effects on inhibiting cell viability and prompting cell apoptosis of PC12 cells. However, GLP-1R agonist geniposide (Gen) significantly reversed them, exerting a protective role on PC12 cells. And IDE antagonist bacitracin (Bac) markedly reversed the protective effects of Gen on Aβ1–42-treated PC12 cells. Besides, Gen significantly reversed the effects of Aβ1–42 treatment on IDE expression, and the inhibitor of cAMP/PKA signaling pathway markedly reversed the effects of Gen on IDE expression level in Aβ1–42-treated PC12 cells. In conclusion, GLP-1R regulates cell growth, at least partially, through regulating cAMP/PKA/IDE signaling pathway in Aβ1–42-treated PC12 cells.