LncRNA JHDM1D-AS1 Suppresses MPP + -Induced Neuronal Injury in Parkinson's Disease via miR-134-5p/PIK3R3 Axis.

Parkinson's disease (PD) is a multi-factorial neurodegenerative disease. Long noncoding RNAs (lncRNAs) have been revealed to be involved in the process of PD. Herein, this study aimed to investigate the potential function and mechanism of JHDM1D-AS1 (JHDM1D antisense 1) in PD process. 1-Methyl-4-phenylpyridinium (MPP +)-induced SK-N-SH cells were used to conduct expression and function analyses. Levels of genes and proteins were examined using real-time reverse transcription PCR (RT-qPCR) and Western blot. Cell viability and apoptosis were determined using CCK-8 assay, flow cytometry, and Western blot, respectively. ELISA analysis was performed for the detection of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α. The contents of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured using commercial kits. The direct interactions between miR-134-5p and PIK3R3 (Phosphoinositide-3-Kinase Regulatory Subunit 3) or JHDM1D-AS1 were verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. JHDM1D-AS1 expression was decreased by MPP + in SK-N-SH cells in a dose- or time-dependent manner. Functionally, JHDM1D-AS1 overexpression attenuated MPP + -evoked neuronal apoptosis, inflammation, and oxidative stress. Mechanistically, JHDM1D-AS1 competitively bound to miR-134-5p to upregulate the expression of its target PIK3R3. Rescue experiments suggested that miR-134-5p upregulation reversed the inhibitory effects of JHDM1D-AS1 on MPP + -induced neuronal injury. Moreover, inhibition of miR-134-5p protected neurons against MPP + -induced neuronal apoptosis, inflammation, and oxidative stress, which were abolished by PIK3R3 silencing. JHDM1D-AS1 protected against MPP + -induced neuron injury via miR-134-5p/PIK3R3 axis, suggesting the potential involvement of this axis in PD process.

Characterization of the antiapoptotic effect of copper sulfate on striatal and midbrain damage induced by MPP+ in rats.

1-Methyl-4-phenylpyridinium ion (MPP+)-induced neurotoxicity produces cellular damage resembling that encountered in Parkinson's disease. The mechanisms of cellular death after MPP+ include the participation of oxidative stress in the loss of dopaminergic neurons. Among the mechanisms of defense against oxidative stress, several copper-dependent proteins have been implicated: Cu/Zn-SOD, ceruloplasmin, and metallothionein. Another important mechanism of damage, is MPP + interference with mitochondrial respiration. Both, oxidative stress and inhibition of mitochondrial respiration may trigger apoptosis in the neurons after MPP+. The aim of the present study was to characterize the time-course of apoptosis induced by MPP+ to determine if copper sulfate pretreatment is able to prevent the activation of caspases and decreased the neuronal apoptosis. MPP+ was microinjected into rat striatum using a stereotactic frame. The results showed increased activities of caspases 8, 9 and 3, between 72-120 hours after administration of MPP+, both in striatum and midbrain. After this study, we tested the effect of CuSO4 on MPP+ neurotoxicity, showing a diminution of the apoptotic damage induced by MPP+, decreased levels of enzymatic activity of caspases: 8 (-34 and -25 %), 9 (-25 and -42 %) and 3 (-40 and -29 %) in striatum and midbrain, respectively. Finally, we performed an immunohistochemical analysis, evidencing a decreased number of apoptotic cells in the groups pretreated with copper sulfate pretreatment compared to the control group. With these findings, it is concluded that pretreatment with copper sulfate may be a good alternative to prevent MPP+-induced apoptosis.

MiR-133b inhibits MPP+-induced apoptosis in Parkinson's disease model by inhibiting the ERK1/2 signaling pathway.

OBJECTIVE: The aim of this study was to explore the effect of micro ribonucleic acid (miR)-133b on 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis in the Parkinson's disease (PD) model. MATERIALS AND METHODS: PC12 cells were induced by different concentrations of MPP+ to establish the PD cell model. Subsequently, the survival rate of PC12 cells was detected using Cell Counting Kit-8 (CCK-8) assay. Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of miR-133b in the PD model induced by different concentrations of MPP+. Next, PC12 cells were transfected with miR-133b mimic and miR-negative control (NC), and divided into MPP+ group, MPP+ + miR-NC group and MPP+ + miR-133b mimic group. Transfection efficiency was verified using qRT-PCR. The apoptosis of cells was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Moreover, the expressions of extracellular signal-regulated kinase 1/2 (ERK1/2) and phosphorylated (p)-ERK1/2 were determined using Western blotting. RESULTS: After MPP+ treatment, the survival rate of PC12 cells significantly declined (p<0.05). MPP+ exhibited toxicity against PC12 cells in a concentration-dependent manner. Meanwhile, cell survival rate decreased remarkably with the increase of MPP+ concentration (p<0.05). With increased concentration of MPP+, the expression of miR-133b in the PD cell model declined significantly (p<0.05). The apoptosis of PC12 cells was remarkably inhibited by overexpression of miR-133b in the PD cell model (p<0.05). In addition, the protein expression of p-ERK1/2 in PC12 cells was notably reduced after overexpression of miR-133b in the PD cell model (p<0.05). CONCLUSIONS: MiR-133b is lowly expressed in the PD cell model. Furthermore, overexpression of miR-133b inhibits cell apoptosis in the PD cell model by regulating the ERK1/2 signaling pathway.

Protective Effect of Fucoidan against MPP+-Induced SH-SY5Y Cells Apoptosis by Affecting the PI3K/Akt Pathway.

The main pathologic changes of the Parkinson's disease (PD) is dopaminergic (DA) neurons lost. Apoptosis was one of the important reasons involved in the DA lost. Our previous study found a fucoidan fraction sulfated heterosaccharide (UF) had neuroprotective activity. The aim of this study was to clarify the mechanism of UF on DA neurons using human dopaminergic neuroblastoma (SH-SY5Y) cells a typical as a PD cellular model. Results showed that UF prevented MPP+-induced SH-SY5Y cells apoptosis and cell death. Additionally, UF pretreated cells increased phosphorylation of Akt, PI3K and NGF, which means UF-treated active PI3K-Akt pathway. Moreover, UF treated cells decreased the expression of apoptosis-associated protein, such as the ratio of Bax/Bcl-2, GSK3ß, caspase-3 and p53 nuclear induced by MPP+. This effect was partially blocked by PI3K inhibitor LY294002. Our data suggested that protective effect of UF against MPP+-induced SH-SY5Y cells death by affecting the PI3K-Akt pathway. These findings contribute to a better understanding of the critical roles of UF in treating PD and may elucidate the molecular mechanisms of UF effects in PD.

Hydroxytyrosol inhibits MAO isoforms and prevents neurotoxicity inducible by MPP+ invivo.

Parkinson's disease is considered to be due to an increase in the catabolism of dopamine by the action of monoamine oxidase (MAO) enzymes which leads to an increase in reactive oxygen species (ROS) and loss of dopaminergic neurons. Here, in a model of neurotoxicity inducible by 1-methyl-4-phenylpyridinium (MPP+), we tested the effect of hydroxytyrosol (HTy), a potent antioxidant, on generation of ROS. Five minutes after a single intravenous administration of 1.5 mg/Kg of Hty, Wistar rats received an intrastriatal micro-injection of 10 micrograms of MPP+ while control animals received saline solution. Six days later, all animals were treated with apomorphine (1 mg/Kg), subcutaneously and ipsilateral rotations were assessed within an hour. Then, the rats were sacrificed, striatal tissues were removed and their catecholamines and MAO-A and B activities were quantitated. Pretreatment with HTy significantly diminished the number of ipsilateral rotations. This recovery correlated with significant preservation of striatal dopamine and significant inhibition of of the MAO activity. These results are consistent with the inhibitory effect of HTy on the MAO isoforms and form a basis for the neuroprotective mechanism of this phenylpropanoid in MPP+ induced Parkinson's disease.

Chrysoeriol mediates mitochondrial protection via PI3K/Akt pathway in MPP+ treated SH-SY5Y cells.

Chrysoeriol is a plant flavone extracted from the roots and leaves of the genus Phyllanthus. Although many biological properties of chrysoeriol have been reported, such as its antioxidant and anti-inflammatory activities, the effects of chrysoeriol on the cellular models of Parkinson's disease (PD) have not yet been elucidated. In the present study, we aimed to investigate whether chrysoeriol prevents neurotoxicity induced by 1-methyl-4-phenylpyridinium iodide (MPP+) in SH-SY5Y cells, a typical in vitro PD model. The cell viability was measured by MTT assay. The morphological changes of apoptotic cell nuclei were observed by Hoechst 33,342 staining. The expression of Bax, Bcl-2 and Caspase-3 were detected by western blot analysis. The mitochondria location in the cells was observed by Mitotracker staining. Mitochondrial membrane potential was evaluated by the JC-10 assay. Treatment with MPP+ significantly caused a decrease in the viability of cells and an increase in apoptosis, as evidenced by the upregulation of apoptotic cells, caspase-3 activity and antiapoptotic ratio. These effects were all reversed by pretreatment with chrysoeriol in SH-SY5Y cells. Moreover, pretreatment with chrysoeriol markedly mitigated the MPP+-caused increases in the levels of the prosurvial signaling proteins, phosphorylated Akt and phosphorylated mTOR. The presence of a specific PI3K inhibitor, wortmannin, particularly abolished the chrysoeriol-induced activation of Akt phosphorylation and prevented the chrysoeriol-induced survival effect. These results indicate that the neuroprotective effect of chrysoeriol against MPP+ treatment requires the activation of PI3K/Akt pathway. Ultimately, chrysoeriol could be a promising therapeutic agent for the further experiment on the treatment of PD.

Discovery of cycloneolignan enantiomers from Isatis indigotica Fortune with neuroprotective effects against MPP+-induced SH-SY5Y cell injury.

A pair of new cycloneolignan enantiomers (1a and 1b) were isolated from the leaves of Isatis indigotica Fortune. Their structures were elucidated by extensive spectroscopic data analysis, including 1D and 2D NMR, HRESIMS, MS/MS analysis, together with theoretical electronic circular dichroism (ECD) calculations. Compounds 1a and 1b were then evaluated for their neuroprotective effects against MPP+-induced SH-SY5Y cell injury. As a result, compounds 1a (77.64%) and 1b (78.62%) exhibited moderate neuroprotective activity at the concentration of 12.5 µM compared with that of MPP+ treated group (62.00% at 1 mM) by MTT assay. Furthermore, Annexin V-FITC/PI analysis showed that apoptosis ratios of 1a and 1b were reduced to 10.99% and 9.31%, respectively.

Hsp90 Co-chaperone p23 contributes to dopaminergic mitochondrial stress via stabilization of PHD2: Implications for Parkinson's disease.

The heat shock factor 90 (hsp90) complex has long been associated with neuropathological phenotypes linked to Parkinson's disease (PD) and its inhibition is neuroprotective in disease models. Hsp90 is conventionally believed to act by suppressing induction of hsp70. Here, we report a novel hsp70-independent mechanism by which Hsp90 may also contribute to PD-associated neuropathology. We previously reported that inhibition of the enzyme prolyl hydroxylase domain 2 (PHD2) in conjunction with increases in hypoxia-inducible factor 1 alpha (HIF1α) results in protection of vulnerable dopaminergic substantia nigra pars compacta (DAergic SNpc) neurons in in vitro and in vivo models of PD. We discovered an increased interaction between PHD2 and the p23:Hsp90 chaperone complex in response to mitochondrial stress elicited by the mitochondrial neurotoxin 1-methyl-4-phenylpyridine (MPP+) within cultured DAergic cells. Genetic p23 knockdown was found to result in decreases in steady-state PHD2 protein and activity and reduced susceptibility to MPP+ neurotoxicity. Administration of the p23 inhibitor gedunin was also neuroprotective in these cells as well as in human induced pluripotent stem cell (iPSC)-derived neurons. Our data suggests that mitochondrial stress-mediated elevations in PHD2 interaction with the p23-hsp90 complex have detrimental effects on the survival of DAergic neurons, while p23 inhibition is neuroprotective. We propose that neurotoxic effects are tied to enhanced PHD2 stabilization by the hsp90-p23 chaperone complex that is abrogated by p23 inhibition. This demonstrates a novel connection between two independent pathways previously linked to PD, hsp90 and PHD2-HIF1α, which could have important implications for here-to-fore unexplored mechanisms underlying PD neuropathology.

SIRT1 mediates salidroside-elicited protective effects against MPP+ -induced apoptosis and oxidative stress in SH-SY5Y cells: involvement in suppressing MAPK pathways.

Parkinson's disease (PD) is a progressive neurodegenerative disease, leading to tremor, rigidity, bradykinesia, and gait impairment. Salidroside has been reported to exhibit antioxidative and neuroprotective properties in PD. However, the underlying neuroprotective mechanisms effects of salidroside are poorly understood. Recently, a growing body of evidences suggest that silent information regulator 1 (SIRT1) plays important roles in the pathophysiology of PD. Hence, the present study investigated the roles of SIRT1 in neuroprotective effect of salidroside against N-methyl-4-phenylpyridinium (MPP+ )-induced SH-SY5Y cell injury. Our findings revealed that salidroside attenuates MPP+ -induced neurotoxicity as evidenced by the increase in cell viability, and the decreases in the caspase-3 activity and apoptosis ratio. Simultaneously, salidroside pretreatment remarkably increased SIRT1 activity, SIRT1 mRNA and protein levels in MPP+ -treated SH-SY5Y cell. However, sirtinol, a SIRT1 activation inhibitor, significantly blocked the inhibitory effects of salidroside on MPP+ -induced cytotoxicity and apoptosis. In addition, salidroside abolished MPP+ -induced the production of reactive oxygen species (ROS), the up-regulation of NADPH oxidase 2 (NOX2) expression, the down-regulations of superoxide dismutase (SOD) activity and glutathione (GSH) level in SH-SY5Y cells, while these effects were also blocked by sirtinol. Finally, we found that the inhibition of salidroside on MPP+ -induced phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) were also reversed by sirtinol in SH-SY5Y cells. Taken together, these results indicated that SIRT1 contributes to the neuroprotection of salidroside against MPP+ -induced apoptosis and oxidative stress, in part through suppressing of mitogen-activated protein kinase (MAPK) pathways.

Isorhynchophylline Attenuates MPP+-Induced Apoptosis Through Endoplasmic Reticulum Stress- and Mitochondria-Dependent Pathways in PC12 Cells: Involvement of Antioxidant Activity.

Endoplasmic reticulum stress (ERS) and mitochondrial dysfunctions are thought to be involved in the dopaminergic neuronal death in Parkinson's disease (PD). In this study, we found that isorhynchophylline (IRN) significantly attenuated 1-methyl-4-phenylpyridinium (MPP+)-induced apoptotic cell death and oxidative stress in PC12 cells. IRN markedly reduced MPP+-induced-ERS responses, indicative of inositol-requiring enzyme 1 (IRE1) phosphorylation and caspase-12 activation. Furthermore, IRN inhibits MPP+-triggered apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal Kinase (JNK) signaling-mediated mitochondria-dependent apoptosis pathway. IRN-mediated attenuation of endoplasmic reticulum modulator caspase-12 activation was abolished by diphenyleneiodonium (DPI) or IRE-1α shRNA, but not by SP600125 or pifithrin-α in MPP+-treated PC12 cells. Inhibitions of MPP+-induced both cytochrome c release and caspase-9 activation by IRN were blocked by pre-treatment with DPI or pifithrin-α, but not by IRE-1α shRNA. IRN blocks the generation of reactive oxygen species upstream of both ASK1/JNK pathway and IRE1/caspase-12 pathway. Altogether, our in vitro findings suggest that IRN possesses potent neuroprotective activity and may be a potential candidate for the treatment of PD.

P7C3 inhibits GSK3ß activation to protect dopaminergic neurons against neurotoxin-induced cell death in vitro and in vivo.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. Although its pathogenesis remains unclear, mitochondrial dysfunction plays a vital role in the pathology of PD. P7C3, an aminopropyl carbazole, possesses a significant neuroprotective ability in several neurodegenerative disorders, including PD. Here, we showed that P7C3 stabilized mitochondrial membrane potential, reduced reactive oxygen species production, and inhibited cytochrome c release in MES23.5 cells (a dopaminergic (DA) cell line) exposed to 1-methyl-4-phenylpyridinium (MPP+). In MES23.5 cells, P7C3 inhibited glycogen synthase kinase-3 beta (GSK3ß) activation induced by MPP+. P7C3 also inhibited p53 activity and repressed Bax upregulation to protect cells from MPP+ toxicity. In addition, the activation of p53 was significantly attenuated with the inhibition of GSK3ß activity by P7C3. Furthermore, P7C3 blocked GSK3ß and p53 activation in the midbrain, and prevented DA neuronal loss in the substantia nigra in 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine mice. Thus, our study demonstrates that P7C3 protects DA neurons from neurotoxin-induced cell death by repressing the GSK3ß-p53-Bax pathway both in vitro and in vivo, thus providing a theoretical basis for P7C3 in the potential clinical treatment of PD.

Mild MPP+ exposure impairs autophagic degradation through a novel lysosomal acidity-independent mechanism.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, but its underlying cause remains unknown. Although recent studies using PD-related neurotoxin MPP+ suggest autophagy involvement in the pathogenesis of PD, the effect of MPP+ on autophagic processes under mild exposure, which mimics the slow progressive nature of PD, remains largely unclear. We examined the effect of mild MPP+ exposure (10 and 200 µM for 48 h), which induces a more slowly developing cell death, on autophagic processes and the mechanistic differences with acute MPP+ toxicity (2.5 and 5 mM for 24 h). In SH-SY5Y cells, mild MPP+ exposure predominantly inhibited autophagosome degradation, whereas acute MPP+ exposure inhibited both autophagosome degradation and basal autophagy. Mild MPP+ exposure reduced lysosomal hydrolase cathepsin D activity without changing lysosomal acidity, whereas acute exposure decreased lysosomal density. Lysosome biogenesis enhancers trehalose and rapamycin partially alleviated mild MPP+ exposure induced impaired autophagosome degradation and cell death, but did not prevent the pathogenic response to acute MPP+ exposure, suggesting irreversible lysosomal damage. We demonstrated impaired autophagic degradation by MPP+ exposure and mechanistic differences between mild and acute MPP+ toxicities. Mild MPP+ toxicity impaired autophagosome degradation through novel lysosomal acidity-independent mechanisms. Sustained mild lysosomal damage may contribute to PD. We examined the effects of MPP+ on autophagic processes under mild exposure, which mimics the slow progressive nature of Parkinson's disease, in SH-SY5Y cells. This study demonstrated impaired autophagic degradation through a reduction in lysosomal cathepsin D activity without altering lysosomal acidity by mild MPP+ exposure. Mechanistic differences between acute and mild MPP+ toxicity were also observed. Sustained mild damage of lysosome may be an underlying cause of Parkinson's disease. Cover Image for this issue: doi: 10.1111/jnc.13338.

The Neuroprotective Role of Insulin Against MPP(+) -Induced Parkinson's Disease in Differentiated SH-SY5Y Cells.

Parkinson's disease (PD) is a common chronic neurodegenerative disorder associated with aging that primarily caused by the death of dopaminergic neurons in the substantia nigra pars compacta (SN). Retinoic acid (RA)-differentiated human neuroblastoma SH-SY5Y cells (SH-SY5Y+RA) have been broadly utilized in studies of mechanisms of the pathogenesis underlying 1-Methyl-4-phenyl pyridinium (MPP(+))-induced PD models. Here, we investigated the neuroprotective mechanisms of insulin on MPP(+)-induced neurotoxicity on SH-SY5Y+RA cells. Recent studies suggest that insulin has a protective effect against oxidative stress but not been elucidated for PD. In this study, pretreatment of insulin prevented the cell death in a dose dependent manner and lowered nitric oxide (NO) release, reactive oxygen species (ROS), and calcium ion (Ca(2+)) influx induced by MPP(+). Insulin also elevated tyrosine hydroxylase (TH) and insulin signaling pathways in dopaminergic neuron through activating PI3K/Akt/GSK-3 survival pathways which in turn inhibits MPP(+)-induced iNOS and ERK activation, and Bax to Bcl-2 ratio. These results suggest that insulin has a protective effect on MPP(+)-neurotoxicity in SH-SY5Y+RA cells.

Crocin protects PC12 cells against MPP(+)-induced injury through inhibition of mitochondrial dysfunction and ER stress.

The molecular machinery that mediates neuronal injury in neurodegenerative conditions such as Parkinson's disease (PD) remains to be fully deciphered, which will hopefully provide novel therapeutic targets for these disorders. Crocin, one of the water-soluble carotenoids isolated from the Crocus sativus L (saffron) stigma, has been reported to exert therapeutic potential in many disease models. Here, we establish an in vitro PD model using 1-methyl-4-phenylpyridinium (MPP(+))-injured PC12 cells to investigate the protective effects of crocin. Crocin treatment significantly attenuated MPP(+)-induced cell injury and apoptosis with little toxicity, and these protective effects were still observed even if crocin treatment was delayed to 6 h after injury. Crocin also inhibited MPP(+)-induced mitochondrial dysfunction, as evidenced by preservation of mitochondrial membrane potential (MMP) and ATP synthesis, which correlates with suppressed endoplasmic reticulum (ER) stress through inhibiting ER chaperone and ER related apoptotic factors. In addition, ER calcium release and morphological changes in ER lumen after MPP(+) exposure were all partially prevented by crocin. By using specific targeted small interfering RNA (siRNA) to knockdown the expression of the C/EBP homologous protein (CHOP), we found that crocin-induced protection and inhibition of ER stress was mediated by inverting MPP(+)-induced decrease of Wnt through the CHOP pathway. Our study demonstrates a pivotal role of ER stress in mediating PD related neuronal injury via the regulation of CHOP-Wnt pathway, and suggests the therapeutic values of crocin against ER stress-associated cytotoxicity.

MicroRNA-7 protects against 1-methyl-4-phenylpyridinium-induced cell death by targeting RelA.

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Mitochondrial complex I impairment in PD is modeled in vitro by the susceptibility of dopaminergic neurons to the complex I inhibitor 1-methyl-4-phenylpyridinium (MPP+). In the present study, we demonstrate that microRNA-7 (miR-7), which is expressed in tyrosine hydroxylase-positive nigral neurons in mice and humans, protects cells from MPP+-induced toxicity in dopaminergic SH-SY5Y cells, differentiated human neural progenitor ReNcell VM cells, and primary mouse neurons. RelA, a component of nuclear factor-κB (NF-κB), was identified to be downregulated by miR-7 using quantitative proteomic analysis. Through a series of validation experiments, it was confirmed that RelA mRNA is a target of miR-7 and is required for cell death following MPP+ exposure. Further, RelA mediates MPP+-induced suppression of NF-κB activity, which is essential for MPP+-induced cell death. Accordingly, the protective effect of miR-7 is exerted through relieving NF-κB suppression by reducing RelA expression. These findings provide a novel mechanism by which NF-κB suppression, rather than activation, underlies the cell death mechanism following MPP+ toxicity, have implications for the pathogenesis of PD, and suggest miR-7 as a therapeutic target for this disease.

3-O-demethylswertipunicoside inhibits MPP⁺-induced oxidative stress and apoptosis in PC12 cells.

The 3-O-demethylswertipunicoside (3-ODS) is extracted from Swertia punicea. Recent study from our laboratory has demonstrated that the 3-ODS protects against oxidative toxicity and apoptosis in PC12 cells (Zhang, S.P., Du, X.G., Pu, X.P., 2010. Biol. Pharm. Bull. 33, 1529-1533). The aim of our study is to further investigate the neuroprotective mechanisms of 3-ODS in 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in PC12 cells. The results indicated that pre-treatment with 3-ODS significantly increased the cell viability compared with MPP(+) treatment. It also alleviated the oxidative stress by increasing superoxide dismutase (SOD) activity and decreasing malondialdehyde (MDA) level and reactive oxygen specise (ROS) production. Moreover, 3-ODS also attenuated MPP(+)-induced apoptosis by inhibiting Bax and Bcl-2 expressions, activating caspase-9, caspase-3, poly (ADP-ribose) polymerase-1 (PARP-1) cleavage, apoptosis-inducing factor (AIF) translocation and α-synuclein expression. These results suggest that 3-ODS might has applications as a complementary medicine for the treatment of Parkinson's disease (PD) or other neurodegenerative diseases.

Simvastatin inhibited the apoptosis of PC12 cells induced by 1-methyl-4-phenylpyridinium ion via inhibiting reactive oxygen species production.

In the present study, we investigated the neuroprotection of simvastatin in PC12 cells following 1-methyl-4-phenylpyridinium ion (MPP+) neurotoxicity. Simvastatin inhibited the decrease of cell viability induced by MPP+ in PC12 cells. The damage of PC12 cells in morphology was alleviated and the apoptotic rates were decreased due to simvatatin pretreatment against MPP+ cytotoxicity. The reactive oxygen species production exposure to MPP+ was inhibited by simvatatin in PC12 cells. So simvastatin may be of therapeutic benefit for PD patients.

Protective effect of BAG5 on MPP+-induced apoptosis in PC12 cells.

OBJECTIVES: Parkinson's disease (PD) is the most common neurodegenerative disease in humans, and an abundance of evidence has implicated apoptosis signaling pathways in the neurodegeneration of PD. The purpose of this study was to assess the role of B-cell lymphoma 2 (Bcl-2)-associated athanogene 5 (BAG5) protein, which was previously confirmed to play an important role in the pathogenesis of PD, in the regulation of apoptosis induced by 1-methyl-4-phenyl-pyridinium (MPP(+)) in PC12 cells. METHODS: PC12 cells were treated with MPP(+) for 48 hours to induce apoptosis, and activation of Bcl-2, Bcl-xl, and caspase 3 was measured by western blot. RESULTS: The upregulation of BAG5 in PC12 cells inhibited apoptosis and increased the expression of anti-apoptotic proteins, including Bcl-2 and Bcl-xl, after MPP(+) treatment. In addition, downregulation of BAG5 in PC12 cells enhanced apoptosis and decreased the expression of these proteins after MPP(+) treatment. DISCUSSION: The data suggest that BAG5 inhibits MPP(+)-induced apoptosis through both endogenous and mitochondria-mediated pathways of apoptosis. Through this mechanism, the upregulation of BAG5 levels may occur through its anti-apoptotic activity in PD.

Neuroprotective efficacy of aminopropyl carbazoles in a mouse model of Parkinson disease.

We previously reported the discovery of P7C3, an aminopropyl carbazole having proneurogenic and neuroprotective properties in newborn neural precursor cells of the dentate gyrus. Here, we provide evidence that P7C3 also protects mature neurons in brain regions outside of the hippocampus. P7C3 blocks 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated cell death of dopaminergic neurons in the substantia nigra of adult mice, a model of Parkinson disease (PD). Dose-response studies show that the P7C3 analog P7C3A20 blocks cell death with even greater potency and efficacy, which parallels the relative potency and efficacy of these agents in blocking apoptosis of newborn neural precursor cells of the dentate gyrus. P7C3 and P7C3A20 display similar relative effects in blocking 1-methyl-4-phenylpyridinium (MPP(+))-mediated death of dopaminergic neurons in Caenorhabditis elegans, as well as in preserving C. elegans mobility following MPP(+) exposure. Dimebon, an antihistaminergic drug that is weakly proneurogenic and neuroprotective in the dentate gyrus, confers no protection in either the mouse or the worm models of PD. We further demonstrate that the hippocampal proneurogenic efficacy of eight additional analogs of P7C3 correlates with their protective efficacy in MPTP-mediated neurotoxicity. In vivo screening of P7C3 analogs for proneurogenic efficacy in the hippocampus may thus provide a reliable means of predicting neuroprotective efficacy. We propose that the chemical scaffold represented by P7C3 and P7C3A20 provides a basis for optimizing and advancing pharmacologic agents for the treatment of patients with PD.

Isolation, structural elucidation, and neuroprotective effects of iridoids from Valeriana jatamansi.

Two new iridoids, jatadoids A (1) and B (2), and two known compounds (3 and 4) were isolated from Valeriana jatamansi. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR). Compound 1 possessed an isovaleroxy group at the C-3 position that has previously been unreported in the class of iridoids. Four compounds were evaluated and compounds 1 and 3 showed moderate neuroprotective effects against MPP+-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.