Human Dopaminergic Cell Line SH-SY5Y Research Articles

Preclinical Evaluation of an Imidazole-Linked Heterocycle for Alzheimer's Disease.

Humanity is facing a vast prevalence of neurodegenerative diseases, with Alzheimer's disease (AD) being the most dominant, without efficacious drugs, and with only a few therapeutic targets identified. In this scenario, we aim to find molecular entities that modulate imidazoline I2 receptors (I2-IRs) that have been pointed out as relevant targets in AD. In this work, we explored structural modifications of well-established I2-IR ligands, giving access to derivatives with an imidazole-linked heterocycle as a common key feature. We report the synthesis, the affinity in human I2-IRs, the brain penetration capabilities, the in silico ADMET studies, and the three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of this new bunch of I2-IR ligands. Selected compounds showed neuroprotective properties and beneficial effects in an in vitro model of Parkinson's disease, rescued the human dopaminergic cell line SH-SY5Y from death after treatment with 6-hydroxydopamine, and showed crucial anti-inflammatory effects in a cellular model of neuroinflammation. After a preliminary pharmacokinetic study, we explored the action of our representative 2-(benzo[b]thiophen-2-yl)-1H-imidazole LSL33 in a mouse model of AD (5xFAD). Oral administration of LSL33 at 2 mg/Kg for 4 weeks ameliorated 5XFAD cognitive impairment and synaptic plasticity, as well as reduced neuroinflammation markers. In summary, this new I2-IR ligand that promoted beneficial effects in a well-established AD mouse model should be considered a promising therapeutic strategy for neurodegeneration.

Insights into the Pharmacokinetics and In Vitro Cell-Based Studies of the Imidazoline I2 Receptor Ligand B06.

The impact of neurodegenerative diseases (ND) is becoming unbearable for humankind due to their vast prevalence and the lack of efficacious treatments. In this scenario, we focused on imidazoline I2 receptors (I2-IR) that are widely distributed in the brain and are altered in patients with brain disorders. We took the challenge of modulating I2-IR by developing structurally new molecules, in particular, a family of bicyclic α-iminophosphonates, endowed with high affinity and selectivity to these receptors. Treatment of two murine models, one for age-related cognitive decline and the other for Alzheimer’s disease (AD), with representative compound B06 ameliorated their cognitive impairment and improved their behavioural condition. Furthermore, B06 revealed beneficial in vitro ADME-Tox properties. The pharmacokinetics (PK) and metabolic profile are reported to de-risk B06 for progressing in the preclinical development. To further characterize the pharmacological properties of B06, we assessed its neuroprotective properties and beneficial effect in an in vitro model of Parkinson’s disease (PD). B06 rescued the human dopaminergic cell line SH-SY5Y from death after treatment with 6-hydroxydopamine (6-OHDA) and showed a crucial anti-inflammatory effect in a cellular model of neuroinflammation. This research reveals B06 as a putative candidate for advancing in the difficult path of drug discovery and supports the modulation of I2-IR as a fresh approach for the therapy of ND.

Inhibition of γH2AX, COX-2 and regulation of antioxidant enzymes in MPP+-exposed SH-SY5Y cells pre-treated with rutin.

Many plant-derived bioactive compounds such as rutin are reportedly effective in attenuating neuronal death in most neurodegenerative disorders. Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra of the midbrain, and has previously been modelled in-vitro through the specific neurotoxic activity of 1-methyl-4-phenylpyridinium (MPP+) on dopaminergic neurons. Rutin is a bioflavonoid with multiple pharmacological effects, and this study investigated the neuroprotective effects of rutin in the human dopaminergic SH-SY5Y cell line using the neurotoxin MPP+. SH-SY5Y cells pretreated with rutin, were exposed to MPP+ and evaluated for cell viability, nitric oxide (NO), reactive oxygen species (ROS) and antioxidant enzymes activities. In addition, western blot techniques were used to determine the protein expression levels of γH2AX and COX-2. Rutin significantly attenuated MPP+-induced loss of cell viability, mitigated ROS and NO production and inhibited the disruption of antioxidant enzymes activity. It was also observed that rutin significantly reduced protein expression levels of γH2AX and COX-2 in SH-SY5Y cells treated with MPP+. Taken together, findings from this study tend to suggest that rutin is a promising neuroprotective compound for the treatment of PD through its effects on some of the mechanisms that characterize this neurodegenerative disease.

Protective effects of valproic acid on 6-hydroxydopamine-induced neuroinjury.

Oxidative stress may play critically important roles in the etiology of Parkinson's disease (PD). 6-Hydroxydopamine (6-OHDA) is a physiological neurotoxin reported to induce oxidative-induced apoptosis of dopaminergic neurons in PD mice models. Valproic acid (VPA), a clinical mood stabilizer, is a HDAC inhibitor with neuroprotective capacities. In the study, we aim at examining the feasibility of VPA as a protector for dopaminergic neurons against damage from 6-OHDA, and the intracellular mechanisms. The 6-OHDA-induced neurotoxicity to the human dopaminergic cell line SH-SY5Y was applied for examining VPA protective effects. Pretreatment with VPA was able to improve cell viability and reduce 6-OHDA-induced reactive oxygen species. Furthermore, a significant suppression of apoptotic caspases including cleaved caspase-3, caspase-7, and caspase-9 was observed. The results also revealed VPA decreased the 6-OHDA-induced Bax/Bcl2 ratio, as measured at protein level. These novel findings indicate that VPA may be capable of protecting the SH-SY5Y dopaminergic neuronal cells from 6-OHDA-induced toxicity via the deceasing of apoptotic caspases (cleaved caspase-3, caspase-7, and caspase-9) and reducing of the Bax/Bcl2 ratio. Very possibly, VPA could serve as not only a mood stabilizer but also a potential antidote for PD prevention.

Phosphodiesterase 7 Regulation in Cellular and Rodent Models of Parkinson's Disease.

Parkinson's disease is characterized by a loss of dopaminergic neurons in the ventral midbrain. This disease is diagnosed when around 50% of these neurons have already died; consequently, therapeutic treatments start too late. Therefore, an urgent need exists to find new targets involved in the onset and progression of the disease. Phosphodiesterase 7 (PDE7) is a key enzyme involved in the degradation of intracellular levels of cyclic adenosine 3', 5'-monophosphate in different cell types; however, little is known regarding its role in neurodegenerative diseases, and specifically in Parkinson's disease. We have previously shown that chemical as well as genetic inhibition of this enzyme results in neuroprotection and anti-inflammatory activity in different models of neurodegenerative disorders, including Parkinson's disease. Here, we have used in vitro and in vivo models of Parkinson's disease to study the regulation of PDE7 protein levels. Our results show that PDE7 is upregulated after an injury both in the human dopaminergic cell line SH-SY5Y and in primary rat mesencephalic cultures and after lipopolysaccharide or 6-hidroxydopamine injection in the Substantia nigra pars compacta of adult mice. PDE7 increase takes place mainly in degenerating dopaminergic neurons and in microglia cells. This enhanced expression appears to be direct since 6-hydroxydopamine and lipopolysaccharide increase the expression of a 962-bp fragment of its promoter. Taking together, these results reveal an essential function for PDE7 in the pathways leading to neurodegeneration and inflammatory-mediated brain damage and suggest novel roles for PDE7 in neurodegenerative diseases, specifically in PD, opening the door for new therapeutic interventions.

Biochemical profile and in vitro neuroprotective properties of Carpobrotus edulis L., a medicinal and edible halophyte native to the coast of South Africa

This work reports the nutritional profile and in vitro neuroprotective properties of leaves of Carpobrotus edulis L., a medicinal and edible succulent species native to the coast of South Africa. Biomass was evaluated for proximate composition and for contents in carotenoids, liposoluble pigments and minerals. Hexane, dichloromethane, ethyl acetate and methanol extracts were prepared by Soxhlet extraction from dried biomass and evaluated for in vitro inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), capacity to attenuate hydrogen peroxide (H2O2)-induced injury in the human dopaminergic cell line SH-SY5Y and for anti-neuroinflammatory potential on lipopolysaccharide (LPS)-stimulated microglia cells. Extracts were evaluated for antioxidant activity by four complementary methods, total content of phenolics, tannins and flavonoids. Finally the profile of the main phenolic compounds was determined by high performance liquid chromatography with diode array detection (HPLC-DAD). C. edulis has a high moisture content, high levels of crude protein, fibre, ash, carotenoids, calcium and iron and a low fat level. The extracts were able to efficiently scavenge the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), reduce iron and chelate copper and iron ions, and exhibited different levels of phenolic compounds in the order ethyl acetate>methanol>dichloromethane>hexane. The main compounds detected were gallic and salicylic acids and quercetin, all in the ethyl acetate extract. The extracts allowed a dual and potent inhibition of AChE and BuChE. The dichloromethane and methanol extracts had the strongest capacity to prevent cell death induced by H2O2, and the methanol extract had anti-neuronflammatory properties. All together our results suggest that consumption of leaves of C. edulis can contribute for a balanced diet, and that they may add to the improvement of cognitive functions. It also suggests possible novel biotechnological applications of C. edulis such as source of molecules and/or products for the food and/or pharmaceutical industries. Studies aiming to the isolation and identification of the bioactive compounds are already in progress.

Cx43 Mediates Resistance against MPP⁺-Induced Apoptosis in SH-SY5Y Neuroblastoma Cells via Modulating the Mitochondrial Apoptosis Pathway.

Neuronal apoptosis in the substantia nigra par compacta (SNpc) appears to play an essential role in the pathogenesis of Parkinson’s disease. However, the mechanisms responsible for the death of dopaminergic neurons are not fully understood yet. To explore the apoptotic mechanisms, we used a well-known parkinsonian toxin, 1-methyl-4-phenylpyridine (MPP+), to induce neuronal apoptosis in the human dopaminergic SH-SY5Y cell line. The most common method of interaction between cells is gap junctional intercellular communication (GJIC) mediated by gap junctions (GJs) formed by transmembrane proteins called connexins (Cx). Modulation of GJIC affects cell viability or growth, implying that GJIC may have an important role in maintaining homeostasis in various organs. Here, we hypothesized that increasing the level of the gap junction protein Cx43 in SH-SY5Y neuroblastoma cells could provide neuroprotection. First, our experiments demonstrated that knocking down Cx43 protein by using Cx43-specific shRNA in SH-SY5Y neuroblastoma cells potentiated MPP+-induced neuronal apoptosis evident from decreased cell viability. In another experiment, we demonstrated that over-expression of Cx43 in the SH-SY5Y cell system decreased MPP+-induced apoptosis based on the MTT assay and reduced the Bax/Bcl-2 ratio and the release of cytochrome C based on Western blot analysis. Taken together, our results suggest that Cx43 could mediate resistance against MPP+-induced apoptosis in SH-SY5Y neuroblastoma cells via modulating the mitochondrial apoptosis pathway.

ChemInform Abstract: 3,4‐seco‐28‐Nor‐oleanane Triterpenes from Camellia japonica Protect from Neurotoxicity in a Rotenone Model of Parkinson′s Disease.

A natural material extract library (Korea Bioactive Natural Material Bank) was screened with respect to their protective effects on neuronal cells, and a 70% ethanol extract from the flowers of Camellia japonica turned out to be a potential hit. Bioassay-guided fractionation of this active extract led to the isolation of six new 3,4-seco-28-nor-oleanane triterpenoids (1–6). The molecular structures of these new triterpenoids were elucidated through extensive spectroscopic analyses, including high-resolution MS and 1D- and 2D-NMR data. In a rotenone model of Parkinson's disease (PD), compounds 3–6 effectively protected against neurotoxicity in the human dopaminergic SH-SY5Y cell line. Among these 3,4-seco-28-nor-oleanane triterpenoids, 4,17β,29-trihydroxy-16-oxo-3,4-seco-28-norolean-12-en-3-oic acid n-butyl ester (5) exerted the strongest neuroprotective effect by suppressing the expression of α-synuclein and the intracellular production of reactive oxygen species (ROS) induced by rotenone treatment. In addition, compound 5 induced microtubule-associated protein 1A/1B-light chain 3 (LC3), which is known as an autophagy biomarker. These results suggest a new class of chemical entities for developing bioactive compounds for PD therapy.

3,4-seco-28-Nor-oleanane triterpenes from Camellia japonica protect from neurotoxicity in a rotenone model of Parkinson's disease

A natural material extract library (Korea Bioactive Natural Material Bank) was screened with respect to their protective effects on neuronal cells, and a 70% ethanol extract from the flowers of Camellia japonica turned out to be a potential hit. Bioassay-guided fractionation of this active extract led to the isolation of six new 3,4-seco-28-nor-oleanane triterpenoids (1–6). The molecular structures of these new triterpenoids were elucidated through extensive spectroscopic analyses, including high-resolution MS and 1D- and 2D-NMR data. In a rotenone model of Parkinson's disease (PD), compounds 3–6 effectively protected against neurotoxicity in the human dopaminergic SH-SY5Y cell line. Among these 3,4-seco-28-nor-oleanane triterpenoids, 4,17β,29-trihydroxy-16-oxo-3,4-seco-28-norolean-12-en-3-oic acid n-butyl ester (5) exerted the strongest neuroprotective effect by suppressing the expression of α-synuclein and the intracellular production of reactive oxygen species (ROS) induced by rotenone treatment. In addition, compound 5 induced microtubule-associated protein 1A/1B-light chain 3 (LC3), which is known as an autophagy biomarker. These results suggest a new class of chemical entities for developing bioactive compounds for PD therapy.

3,4-methylenedioxypyrovalerone (MDPV) Induces Cytotoxic Effects on Human Dopaminergic SH-SY5Y Cells

Background. Synthetic cathinones are a rapidly growing group of psychostimulant drugs usually referred to as bath salts and have been used as an alternative to classic amphetamine-like drugs, with 3,4-methylenedioxypyrovalerone (MDPV) being one of the most prevalent constituents. Consistent with the effects of other psychostimulants, MDPV may induce neurotoxicity by altering monoamine systems in the brain or by inducing neuronal apoptosis. Purpose. The aim of this study was to evaluate the effects of MDPV on the human dopaminergic cell line SH-SY5Y. Experimental design. After 24-hour exposure to MDPV (100µ Mt o 2.5 mM), cytotoxicity, cellular proliferation, and apoptosis were evaluated, whereas reactive oxygen species (ROS) production was evaluated at 2 h, 4 h, 6 h, 22 h, and 24 h. Results. MDPV increased ROS production after 1 h, 4 h, and 6 h of exposure in all but the highest concentration; a moderate increase was observed at 22 h and 24 h. Only high concentrations of the drug decreased cellular proliferation and induced apoptosis and necrosis. Conclusion. MDPV induces dopaminergic toxicity by decreasing cellular proliferation and by increasing apoptosis and necrosis. The production of ROS may play a role in the early response to the drug.

Neuroprotection of inositol hexaphosphate and changes of mitochondrion mediated apoptotic pathway and α-synuclein aggregation in 6-OHDA induced parkinson׳s disease cell model

Animal and cell experiments showed that inositol hexaphosphate (IP6) was protective on neurons in parkinson׳s disease (PD) model, but the underlying mechanism of this action was not extensively elucidated. To address this question, we established 6-hydroxydopamine (6-OHDA) induced human dopaminergic cell line SH-SY5Y as PD cell model and testified the neuroprotection of IP6. Through hoechst nuclear stain method and flow cytometric analysis, apoptosis induced by 6-OHDA was blocked by IP6 pretreatment. Significant protection against reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) was observed in 6-OHDA induced cells pretreated with IP6. To further investigate the mechanism of anti-apoptotic effect of IP6, expression of mediators in mitochondrion dependent apoptotic pathway was detected. Results indicated that loss of mitochondrial membrane potential, cytochrome c releasing, upregulation of Bcl-2-associated X protein (Bax), downregulation of B-cell CLL/lymphoma 2 (Bcl-2) and caspases activation were reversed by IP6. In addition, using flow cytometric method and western blot approach, our data showed that IP6 attenuated the rise of calcium and α-synuclein aggregation in cytosol. Collectively, IP6 exerted its neuroprotection on dopaminergic cells in PD cell model and the mechanism may be associated with changes of mitochondrion mediated apoptotic pathway and α-synuclein aggregation.

Botryococcus braunii and Nannochloropsis oculata extracts inhibit cholinesterases and protect human dopaminergic SH-SY5Y cells from H2O2-induced cytotoxicity

Extracts of Botryococcus braunii and Nannochloropsis oculata were evaluated for inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase (TYRO) and capacity to attenuate hydrogen peroxide (H2O2)-induced injury in the human dopaminergic cell line SH-SY5Y. We also report the antioxidant activity, the total phenolic content (TPC) and the fatty acid (FA) profile of these microalgae. Both species had low levels of TPC and considerable amounts of polyunsaturated fatty acids (PUFA). The highest radical scavenging activity (RSA) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) was observed in the acetone extract of B. braunii and in the diethyl ether extracts of both strains. The acetone extract of B. braunii had the highest RSA against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid). The extracts had a higher capacity to chelate iron than copper, and the highest iron chelation was achieved with the hexane extract of N. oculata. The diethyl ether and water extracts of the latter species also displayed the highest copper chelation. Except for the acetone extract of B. braunii and the water extract of N. oculata, all samples inhibited AChE, especially the hexane extract of N. oculata. Samples had moderate BChE inhibition and no effect towards TYRO. Almost all samples effectively protected neuronal cells against oxidative stress induced by H2O2. These results suggest possible novel applications of biomass from those microalgae in the pharmaceutical industry and/or as functional foods.

Heat shock protein 60: an endogenous inducer of dopaminergic cell death in Parkinson disease.

BackgroundIncreasing evidence suggests that inflammation associated with microglial cell activation in the substantia nigra (SN) of patients with Parkinson disease (PD) is not only a consequence of neuronal degeneration, but may actively sustain dopaminergic (DA) cell loss over time. We aimed to study whether the intracellular chaperone heat shock protein 60 (Hsp60) could serve as a signal of CNS injury for activation of microglial cells.MethodsHsp60 mRNA expression in the mesencephalon and the striatum of C57/BL6 mice treated with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and the Hsp60/TH mRNA ratios in the SN of PD patients and aged-matched subjects were measured. To further investigate a possible link between the neuronal Hsp60 response and PD-related cellular stress, Hsp60 immunoblot analysis and quantification in cell lysates from SH-SY5Y after treatment with 100 μM MPP+ (1-methyl-4-phenylpyridinium) at different time points (6, 12, 24 and 48 hours) compared to control cells were performed. Additional MTT and LDH assay were used. We next addressed the question as to whether Hsp60 influences the survival of TH+ neurons in mesencephalic neuron-glia cultures treated either with MPP+ (1 μM), hHsp60 (10 μg/ml) or a combination of both. Finally, we measured IL-1β, IL-6, TNF-α and NO-release by ELISA in primary microglial cell cultures following treatment with different hHsp60 preparations. Control cultures were exposed to LPS.ResultsIn the mesencephalon and striatum of mice treated with MPTP and also in the SN of PD patients, we found that Hsp60 mRNA was up-regulated. MPP+, the active metabolite of MPTP, also caused an increased expression and release of Hsp60 in the human dopaminergic cell line SH-SY5Y. Interestingly, in addition to being toxic to DA neurons in primary mesencephalic cultures, exogenous Hsp60 aggravated the effects of MPP+. Yet, although we demonstrated that Hsp60 specifically binds to microglial cells, it failed to stimulate the production of pro-inflammatory cytokines or NO by these cells.ConclusionsOverall, our data suggest that Hsp60 is likely to participate in DA cell death in PD but via a mechanism unrelated to cytokine release.

Extracts from Quercus sp. acorns exhibit in vitro neuroprotective features through inhibition of cholinesterase and protection of the human dopaminergic cell line SH-SY5Y from hydrogen peroxide-induced cytotoxicity

In this work non polar (hexane) and polar (methanol and hot water) extracts of cork oak (Quercus suber) and holm oak (Quercus ilex) acorns were evaluated for the first time for in vitro neuroprotective properties, by determining their in vitro inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and their capacity to attenuate hydrogen peroxide-induced injury in the human dopaminergic cell line SH-SY5Y. Total content of phenolics, tannins and flavonoids, HPLC profile of the main phenolic compounds and antioxidant activity were also determined. The methanol extracts showed inhibitory activities against AChE and BChE. The best results toward AChE were obtained with cork oak extract (69.4% inhibition at the concentration of 1mg/ml), while for BChE the highest inhibition (46% inhibition at the concentration of 1mg/ml) was obtained with holm oak. Moreover, methanol extracts were able to prevent oxidative stress-induced cytotoxicity in SH-S5SY cells. The methanol extract of holm oak exhibited the highest RSA, with values of 63.8% and 49.7% on DPPH and ABTS radicals at the concentration of 1mg/ml, respectively. In general the extracts exhibited no reducing potential. The methanol extract from cork oak acorns had the highest content in phenolic compounds (25.2mg GAE/g, DW), while the water extracts had the maximum level of flavonoids (1.7mg RE/g, DW). Tannins were present in higher amounts in the water extract of holm oak (91.6CE/g, DW). The main compounds in the methanol extract from holm oak acorns were (−)-epicatechin and catechol, while gallic acid and (+)-catechin were the main constituents of the methanol extract from cork oak acorns. Our results indicate that cork and holm oak acorns provide a valuable source of biomolecules useful for alleviating symptoms associated with Alzheimer's disease and other neurodegenerative ailments.

Phosphodiesterase 7 Inhibition Preserves Dopaminergic Neurons in Cellular and Rodent Models of Parkinson Disease

BackgroundPhosphodiesterase 7 plays a major role in down-regulation of protein kinase A activity by hydrolyzing cAMP in many cell types. This cyclic nucleotide plays a key role in signal transduction in a wide variety of cellular responses. In the brain, cAMP has been implicated in learning, memory processes and other brain functions.Methodology/Principal FindingsHere we show a novel function of phosphodiesterase 7 inhibition on nigrostriatal dopaminergic neuronal death. We found that S14, a heterocyclic small molecule inhibitor of phosphodiesterase 7, conferred significant neuronal protection against different insults both in the human dopaminergic cell line SH-SY5Y and in primary rat mesencephalic cultures. S14 treatment also reduced microglial activation, protected dopaminergic neurons and improved motor function in the lipopolysaccharide rat model of Parkinson disease. Finally, S14 neuroprotective effects were reversed by blocking the cAMP signaling pathways that operate through cAMP-dependent protein kinase A.Conclusions/SignificanceOur findings demonstrate that phosphodiesterase 7 inhibition can protect dopaminergic neurons against different insults, and they provide support for the therapeutic potential of phosphodiesterase 7 inhibitors in the treatment of neurodegenerative disorders, particularly Parkinson disease.

A Nucleotide-based Drug Protects Against Glutamate- and MPP+- Induced Neurotoxicity

Nucleo CMP Forte(R) is a nucleotide-based drug consisting of cytidinemonophosphate, uridinemonophosphate, uridin-ediphosphate and uridinetriphosphate. It has been prescribed for peripheral nervous system disorders, such as lum-bosciatalgia, diabetic or alcoholic polyneuropathy, or trigeminal neuralgia. Its effects on brain pathologies has re-ceived little attention. We examined its neuroprotective effects on cell toxicity induced by glutamate excitotoxicity or by 1-methyl-4-phenyl-pyridinium (MPP+), an in vitro cell model of Parkinson’s disease. We used the human dopaminergic cell line SH-SY5Y and a primary culture of rat cortical cells pre-treated with the drug for 24 hours and then exposed to MPP+ or glutamate at a range of concentrations. Cell viability was measured at different times. Nucleo CMP Forte(R) pre-treatment significantly increased the rate of cell division in SH-SY5Y cells, as well as the synthesis of triglycerides and phospholipids. More interestingly, drug pre-treatment significantly reduced MPP+- and glutamate-induced cell death in SH-SY5Y cells and in rat cortical cells. These results indicate that the nucleotides included in Nucleo CMP Forte(R) are promising therapeutic molecules for the prevention of neuronal death in brain caused by focal ischemia, Parkinson’s disease or other neurodegenerative pathologies.

Curcumin I protects the dopaminergic cell line SH-SY5Y from 6-hydroxydopamine-induced neurotoxicity through attenuation of p53-mediated apoptosis

Oxidative stress (OS) plays a pivotal role in the pathogenesis of Parkinson's disease (PD). 6-Hydroxydopamine (6-OHDA) is a neurotoxin used to induce oxidative cell death of dopaminergic neurons in experimental models of PD. Curcumin I, or diferuloylmethane is a pure compound isolated from Curcuma longa Linn. that has been reported to have neuroprotective properties. The precise mechanism, however, remains unclear. This study aims to elucidate the mechanisms by which curcumin I exerts its effects, using 6-OHDA-induced neurotoxicity in the human dopaminergic cell line SH-SY5Y. In our experiments, pretreatment with curcumin I improved cell viability, and significantly reduced reactive oxygen species (ROS). Further investigations revealed a reduction of p53 phosphorylation and decrease of the Bax/Bcl-2 ratio, as measured by mRNA expression and protein level. Taken together, these findings indicate that curcumin I protects dopaminergic neurons from 6-OHDA-induced toxicity via the reduction of ROS production, and subsequent attenuation of p53 phosphorylation and reduction of the Bax/Bcl-2 ratio.

A Detoxified Extract ofRhus vernicifluaStokes Upregulated the Expression of BDNF and GDNF in the Rat Brain and the Human Dopaminergic Cell Line SH-SY5Y

Rhus verniciflua Stokes (RVS) has traditionally been used as a food supplement and a traditional herbal medicine for centuries in Korea. This study attempted to evaluate the effects of RVS on the expression of Brain derived neurotrophic factor (BDNF) and Glial cell line-derived neurotrophic factor (GDNF) in SH-SY5Y cells and the rat brain. The results indicated that RVS is a potent inducer of Neurotrophic factor (NTF) production both in vitro and in vivo. Treatment with 10 µg/ml and 10 mg/kg RVS for 4 h of SH-SY5Y cells and rats yielded significant increases in BDNF and GDNF protein levels. We also detected BDNF and GDNF immunoreactive neurons in the rat brain. Both BDNF and GDNF-immunohistochemical staining was markedly enhanced in the animals treated with RVS. These results suggest that RVS serves as an ideal adjuvant in regard to regulating NTF expression, and can contribute to neuroprotection in neurodegenerative diseases.

PF9601N [N-(2-propynyl)-2-(5-benzyloxy-indolyl) methylamine] confers MAO-B independent neuroprotection in ER stress-induced cell death

Endoplasmic reticulum (ER) stress has recently been proposed as one of the factors contributing to apoptotic cell death in Parkinson's disease (PD). Although MAO-B inhibitors have been suggested to exert neuroprotective effects in several experimental models of PD, their effectiveness against ER stress has not been fully determined. Therefore, we have studied the potential usefulness of PF9601N, a non-amphetamine-like MAO-B inhibitor, in preventing cell death in a cell culture model of ER stress. Exposure of human dopaminergic cell line SH-SY5Y to the ER stressor brefeldin A led to Golgi disassembly, activation of the unfolded protein response (UPR), and subsequent expression of the proapoptotic mediator GADD153/CHOP. In this context, PF9601N pretreatment prevented brefeldin A-induced UPR responses, thus blocking the expression of GADD153/CHOP and resulting apoptotic features. In summary, our data suggests that PF9601N is able to block the responses elicited by ER stress, thus preventing apoptotic cell death in brefeldin A-treated cells.

Silencing of human α-synuclein in vitro and in rat brain using lentiviral-mediated RNAi

Human α-synuclein overexpression and its toxic accumulation in neurons or glia are known to play key roles in the pathogenesis of Parkinson's disease and other related neurodegenerative synucleinopathies. Several single point mutations in the α-synuclein gene, as well as gene duplication and triplication, have been linked to familial Parkinson's disease. Moreover, genetic variability of the α-synuclein gene promoter is associated with idiopathic Parkinson's disease. Silencing of the human α-synuclein gene by vector-based RNA interference (RNAi) is a promising therapeutic approach for synucleinopathies. Here, we report identification of a 21-nucleotide sequence in the coding region of human α-synuclein that constitutes an effective target for robust silencing by RNAi and demonstrate allele-specific silencing of the A53T mutant of human α-synuclein. Furthermore, we have developed a plasmid vector-based RNAi for silencing of human α-synuclein in vitro. Lastly, using a dual cassette lentivirus that co-expresses an α-synuclein-targeting small hairpin RNA (shRNA) and enhanced green fluorescent protein (EGFP) as a marker gene, we demonstrate effective silencing of endogenous human α-synuclein in vitro in the human dopaminergic cell line SH-SY5Y and also of experimentally expressed human α-synuclein in vivo in rat brain. Our results demonstrate potent silencing of human α-synuclein expression in vitro and in vivo by viral vector-based RNAi and provide the tools for developing effective gene silencing therapeutics for synucleinopathies, including Parkinson's disease.