[Different concentrations of adapalene induce differentiation and apoptosis of SH-SY5Y cells]

OBJECTIVES

To investigate the effects of different concentrations of adapalene on the morphology and functions of neuroblastoma cell line SH-SY5Y, as well as its role in inducing cell differentiation and apoptosis.

METHODS

SH-SY5Y cells were divided into control group, low concentration (0.1 μM and 1 μM) adapalene groups, and high concentration (10 μM) adapalene group. Time-lapse microscopy was used to observe the morphological changes of SH-SY5Y cells. Immunofluorescence staining was performed to detect the expression of neuronal specific marker βIII-tubulin and mature neuronal marker neurofilament heavy polypeptide (NFH). Multi-electrode array was used to record the electrophysiological features of SH-SY5Y cells. Cell apoptosis was evaluated using a cell apoptosis detection kit.

RESULTS

Low concentrations of adapalene promoted the formation of neurite outgrowth in SH-SY5Y cells, with the neurites interconnected to form a network. Spontaneous discharge activity was observed in SH-SY5Y cells treated with low concentrations of adapalene. Compared to the control group, the expression of βIII-tubulin and NFH increased in the 1 μM adapalene group, while the level of cell apoptosis increased in the high concentration adapalene group (P<0.05).

CONCLUSIONS

Low concentrations of adapalene can induce differentiation of SH-SY5Y cells into mature functional neurons, while high concentrations of adapalene can induce apoptosis in SH-SY5Y cells.

Effects of barakol from Cassia siamea on neuroblastoma SH-SY5Y cell line: A potential combined therapy with doxorubicin

Management of neuroblastoma is challenging because of poor response to drugs, chemotherapy resistance, high relapse, and treatment failures. Doxorubicin is a potent anticancer drug commonly used for neuroblastoma treatment. However, doxorubicin induces considerable toxicities, particularly those caused by oxidative-related damage. To minimize drug-induced adverse effects, the combined use of anticancer drugs with natural-derived compounds possessing antioxidant properties has become an interesting treatment strategy. Barakol is a major compound found in Cassia siamea, an edible plant with antioxidant and anticancer properties. Therefore, barakol could potentially be used in combination with doxorubicin to synergize the anticancer effect, while minimizing the oxidative-related toxicities. Herein, the potential of barakol (0.0043-43.0 μM) to synergize the anticancer effect of low-dose doxorubicin (0.5 and 1.0 μM) was investigated. Results indicated that barakol could enhance the cytotoxic effect of low-dose doxorubicin by affecting the cell viability of the treated cells. Furthermore, the co-treatment with barakol and low-dose doxorubicin decreased the levels of intracellular ROS when compared with the control. Moreover, the antimetastatic effect of the barakol itself was studied through its ability to inhibit metalloproteinase-3 (MMP-3) activity and prevent cell migration. Results revealed that the barakol inhibited MMP-3 activity and prevented cell migration in time- and dose-dependent manners. Additionally, barakol was a non-cytotoxic agent against the normal tested cell line (MRC-5), which suggested its selectivity and safety. Taken together, barakol could be a promising compound to be further developed for combination treatment with low-dose doxorubicin to improve therapeutic effectiveness but decrease drug-induced toxicities. The inhibitory effects of barakol on MMP-3 activity and cancer cell migration also supported its potential to be developed as an antimetastatic agent.

Degree of differentiation impacts neurobiological signature and resistance to hypoxia of SH-SY5Y cells

Objective.SH-SY5Y cells are valuable neuronalin vitromodels for studying patho-mechanisms and treatment targets in brain disorders due to their easy maintenance, rapid expansion, and low costs. However, the use of various degrees of differentiation hampers appreciation of results and may limit the translation of findings to neurons or the brain. Here, we studied the neurobiological signatures of SH-SY5Y cells in terms of morphology, expression of neuronal markers, and functionality at various degrees of differentiation, as well as their resistance to hypoxia. We compared these to neurons derived from human induced pluripotent stem cells (hiPSCs), a well-characterized neuronalin vitromodel.Approach.We cultured SH-SY5Y cells and neurons derived from hiPSCs on glass coverslips or micro-electrode arrays. We studied expression of mature neuronal markers, electrophysiological activity, and sensitivity to hypoxia at various degrees of differentiation (one day up to three weeks) in SH-SY5Y cells. We used hiPSC derived neurons as a reference.Main results.Undifferentiated and shortly differentiated SH-SY5Y cells lacked neuronal characteristics. Expression of neuronal markers and formation of synaptic puncta increased during differentiation. Longer differentiation was associated with lower resistance to hypoxia. At three weeks of differentiation, MAP2 expression and vulnerability to hypoxia were similar to hiPSC-derived neurons, while the number of synaptic puncta and detected events were significantly lower. Our results show that at least three weeks of differentiation are necessary to obtain neurobiological signatures that are comparable to those of hiPSC-derived neurons, as well as similar sensitivities to metabolic stress. Significance.This indicates that extended differentiation protocols should be used to study neuronal characteristics and to model brain disorders with SH-SY5Y cells. We provided insights that may offer the basis for the utilization of SH-SY5Y cells as a more relevant neuronal model in the study of brain disorders.

Monocarboxylate Transporters 1 and 2 Are Responsible for L-Lactate Uptake in Differentiated Human Neuroblastoma SH-SY5Y Cells

L-Lactate transport via monocarboxylate transporters (MCTs) in the central nervous system, represented by the astrocyte-neuron lactate shuttle (ANLS), is crucial for the maintenance of brain functions, including memory formation. Previously, we have reported that MCT1 contributes to L-lactate transport in normal human astrocytes. Therefore, in this study, we aimed to identify transporters that contribute to L-lactate transport in human neurons. SH-SY5Y cells, which are used as a model for human neurons, were differentiated using all-trans-retinoic acid. L-Lactate uptake was measured using radiolabeled L-lactate, and the expression of MCT proteins was confirmed Western blotting. L-Lactate transport was pH-dependent and saturated at high concentrations. Kinetic analysis suggested that L-lactate uptake was biphasic. Furthermore, MCT1, 2 selective inhibitors inhibited L-lactate transport. In addition, the expression of MCT1 and 2 proteins, but not MCT4, was confirmed. In this study, we demonstrated that MCT1 and 2 are major contributors to L-lactate transport in differentiated human neuroblastoma SH-SY5Y cells from the viewpoint of kinetic analysis. These results lead to a better understanding of ANLS in humans, and further exploration of the factors that can promote MCT1 and 2 functions is required.

NTRK1-mediated protection against manganese-induced neurotoxicity and cell apoptosis via IGF2 in SH-SY5Y cells

BACKGROUND

Excessive manganese (Mn) exposure has been linked to neurotoxicity, cognitive impairments. Neurotrophic Receptor Kinase 1 (NTRK1) encodes Tropomyosin kinase A (TrkA), a neurotrophic receptor, as a mediator of neuron differentiation and survival. Insulin-like growth factor 2 (IGF2), a pivotal member of the insulin gene family, plays a crucial role in brain development and neuroprotection. Despite this knowledge, the precise mechanisms through which NTRK1 and IGF2 influence cell responses to Mn-induced neuronal damage remain elusive.

METHODS

Cell apoptosis was assessed using CCK8, TUNEL staining, and Western blot analysis of cleaved Caspase-3. Lentiviral vectors facilitated NTRK1 overexpression, while small interfering RNAs (siRNAs) facilitated IGF2 knockdown. Real-time Quantitative PCR (qPCR) determined gene expression levels, while Western blotting measured protein expression.

RESULTS

The study reveals that NTRK1 inhibits MnCl2-induced apoptosis in SH-SY5Y cells. NTRK1 overexpression significantly upregulated IGF2 expression, and subsequent siRNA-IGF2 experiments confirmed IGF2's pivotal role in NTRK1-mediated neuroprotection. Notably, the study identifies that NTRK1 regulates the expression of IGF2 in the neuroprotective mechanism with the involvement of ER stress pathways.

DISCUSSION

The study reveals NTRK1's neuroprotective role via IGF2 against Mn-induced neurotoxicity and ER stress modulation in SH-SY5Y cells. These findings offer insights into potential therapies for neurodegenerative disorders related to Mn exposure and NTRK1 dysfunction, driving future research in this domain.

Interaction of the C9orf72-Amyotrophic Lateral Sclerosis-Related Proline-Arginine Dipeptide Repeat Protein with the RNA-Binding Protein NOVA1 Causes Decreased Expression of UNC13A Due to Enhanced Inclusion of Cryptic Exons, Which Is Reversed by Betulin Treatment

C9orf72 mutations are the most common form of familial amyotrophic lateral sclerosis (C9-ALS). It causes the production of proline-arginine dipeptide repeat proteins (PR-DPRs) in motor neurons (MNs), leading to the molecular pathology characteristic of ALS. UNC13A is critical for maintaining the synaptic function of MNs. Most ALS patients have nuclear deletion of the splicing repressor TDP-43 in MNs, which causes inclusion of the cryptic exon (CE) of UNC13A mRNA, resulting in nonsense-mediated mRNA decay and reduced protein expression. Therefore, in this study, we explored the role of PR-DPR in CE inclusion of UNC13A mRNA. Our results showed that PR-DPR (PR50) induced CE inclusion and decreased the protein expression of UNC13A in human neuronal cell lines. We also identified an interaction between the RNA-binding protein NOVA1 and PR50 by yeast two-hybrid screening. NOVA1 expression is known to be reduced in patients with ALS. We found that knockdown of NOVA1 enhanced CE inclusion of UNC13A mRNA. Furthermore, the naturally occurring triterpene betulin can inhibit the interaction between NOVA1 and PR50, thus preventing CE inclusion of UNC13A mRNA and protein reduction in human neuronal cell lines. This study linked PR-DPR with CE inclusion of UNC13A mRNA and developed candidate therapeutic strategies for C9-ALS using betulin.

Chiisanoside Mediates the Parkin/ZNF746/PGC-1α Axis by Downregulating MiR-181a to Improve Mitochondrial Biogenesis in 6-OHDA-Caused Neurotoxicity Models In Vitro and In Vivo: Suggestions for Prevention of Parkinson's Disease

The degeneration of dopamine (DA) neurons is known to be associated with defects in mitochondrial biogenesis caused by aging, environmental factors, or mutations in genes, leading to Parkinson's disease (PD). As PD has not yet been successfully cured, the strategy of using small molecule drugs to protect and restore mitochondrial biogenesis is a promising direction. This study evaluated the efficacy of synthetic chiisanoside (CSS) identified in the leaves of Acanthopanax sessiliflorus to prevent PD symptoms. The results show that in the 6-hydroxydopamine (6-OHDA) model, CSS pretreatment can effectively alleviate the reactive oxygen species generation and apoptosis of SH-SY5Y cells, thereby lessening the defects in the C. elegans model including DA neuron degeneration, dopamine-mediated food sensitivity behavioral disorders, and shortened lifespan. Mechanistically, we found that CSS could restore the expression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α), a key molecule in mitochondrial biogenesis, and its downstream related genes inhibited by 6-OHDA. We further confirmed that this is due to the enhanced activity of parkin leading to the ubiquitination and degradation of PGC-1α inhibitor protein Zinc finger protein 746 (ZNF746). Parkin siRNA treatment abolished this effect of CSS. Furthermore, we found that CSS inhibited 6-OHDA-induced expression of miR-181a, which targets parkin. The CSS's ability to reverse the 6-OHDA-induced reduction in mitochondrial biogenesis and activation of apoptosis was abolished after the transfection of anti-miR-181a and miR-181a mimics. Therefore, the neuroprotective effect of CSS mainly promotes mitochondrial biogenesis by regulating the miR-181a/Parkin/ZNF746/PGC-1α axis. CSS potentially has the opportunity to be developed into PD prevention agents.

Preventive Roles of Rice-koji Extracts and Ergothioneine on Anxiety- and Pain-like Responses under Psychophysical Stress Conditions in Male Mice

This study determined the effect of daily administration of Rice-koji on anxiety and nociception in mice subjected to repeated forced swim stress (FST). In a parallel experiment, it was determined whether ergothioneine (EGT) contained in Rice-koji displayed similar effects. Anxiety and nociception were assessed behaviorally using multiple procedures. c-Fos and FosB immunoreactivities were quantified to assess the effect of both treatments on neural responses in the paraventricular nucleus of the hypothalamus (PVN), nucleus raphe magnus (NRM), and lumbar spinal dorsal horn (DH). FST increased anxiety- and pain-like behaviors in the hindpaw. Rice-koji or EGT significantly prevented these behaviors after FST. In the absence of formalin, both treatments prevented decreased FosB expressions in the PVN after FST, while no effect was seen in the NRM and DH. In the presence of formalin, both treatments prevented changes in c-Fos and FosB expressions in all areas in FST mice. Further, in vitro experiments using SH-SY5Y cells were conducted. Rice-koji and EGT did not affect cell viability but changed the level of brain-derived neurotrophic factor. In conclusion, Rice-koji could reduce anxiety and pain associated with psychophysical stress, possibly mediated by the modulatory effects of EGT on neural functions in the brain.

Postmortem Brains from Subjects with Diabetes Mellitus Display Reduced GLUT4 Expression and Soma Area in Hippocampal Neurons: Potential Involvement of Inflammation

Diabetes mellitus (DM) is an important risk factor for dementia, which is a common neurodegenerative disorder. DM is known to activate inflammation, oxidative stress, and advanced glycation end products (AGEs) generation, all capable of inducing neuronal dysfunctions, thus participating in the neurodegeneration progress. In that process, disturbed neuronal glucose supply plays a key role, which in hippocampal neurons is controlled by the insulin-sensitive glucose transporter type 4 (GLUT4). We investigated the expression of GLUT4, nuclear factor NF-kappa B subunit p65 [NFKB (p65)], carboxymethyllysine and synapsin1 (immunohistochemistry), and soma area in human postmortem hippocampal samples from control, obese, and obese+DM subjects (41 subjects). Moreover, in human SH-SY5Y neurons, tumor necrosis factor (TNF) and glycated albumin (GA) effects were investigated in GLUT4, synapsin-1 (SYN1), tyrosine hydroxylase (TH), synaptophysin (SYP) proteins, and respective genes; NFKB binding activity in the SLC2A4 promoter; effects of increased histone acetylation grade by histone deacetylase 3 (HDAC3) inhibition. Hippocampal neurons (CA4 area) of obese+DM subjects displayed reduced GLUT4 expression and neuronal soma area, associated with increased expression of NFKB (p65). Challenges with TNF and GA decreased the SLC2A4/GLUT4 expression in SH-SY5Y neurons. TNF decreased SYN1, TH, and SYP mRNAs and respective proteins, and increased NFKB binding activity in the SLC2A4 promoter. Inhibition of HDAC3 increased the SLC2A4 expression and the total neuronal content of CRE-binding proteins (CREB/ICER), and also counterbalanced the repressor effect of TNF upon these parameters. This study revealed reduced postmortem human hippocampal GLUT4 content and neuronal soma area accompanied by increased proinflammatory activity in the brains of DM subjects. In isolated human neurons, inflammatory activation by TNF reduced not only the SLC2A4/GLUT4 expression but also the expression of some genes related to neuronal function (SYN1, TH, SYP). These effects may be related to epigenetic regulations (H3Kac and H4Kac status) since they can be counterbalanced by inhibiting HDAC3. These results uncover the improvement in GLUT4 expression and/or the inhibition of HDAC3 as promising therapeutic targets to fight DM-related neurodegeneration.

Garcinol protects SH-SY5Y cells against MPP+-induced cell death by activating DJ-1/SIRT1 and PGC-1α mediated antioxidant pathway in sequential stimulation of p-AMPK mediated autophagy

Parkinson's disease (PD), a chronic and progressive neurodegenerative disease, can reduce the population of dopaminergic neurons in the substantia nigra. The cause of this neuronal death remains unclear. 1-Methyl-4-phenylpyridinium ion (MPP+) is a potent neurotoxin that can destroy dopaminergic (DA) neurons and promote PD. Garcinol, a polyisoprenylated benzophenone derivative, was extracted from Garcinia indica and is an important active compound it has been used as an anticancer, antioxidant, and anti-inflammatory, agent and it can suppress reactive oxygen species (ROS) mediated cell death in a PD model. Human neuroblastoma (SH-SY5Y) cells (1 × 10⁵  cells) were treated with MPP+ (1 mM) for 24 h to induce cellular ROS production. The formation of ROS was suppressed by pretreatment with different concentrations of garcinol (0.5 and 1.0 μM) for 3 h in SH-SY5Y cells. The present study found that MPP+ treatment increased the formation of reactive oxygen species (ROS), and the increased ROS began to promote cell death in SH-SY5Y cells. However, our natural compound garcinol effectively blocked MPP+-mediated ROS formation by activating the DJ-1/SIRT1 and PGC-1α mediated antioxidant pathway. Further findings indicate that the activated SIRT1 can also regulate p-AMPK-mediated autophagy to protect the neurons from the damage it concludes that garcinol sub-sequential regulates intracellular autophagy in this model, and the productive efficacy of garcinol was confirmed by western blot analysis and MitoSOX DCFDA and MTT assays. The results showed garcinol increased protection due to the prevention of MPP+-induced ROS and the promotion of cell survival.

In Vitro Effects of Acitretin on Human Neuronal SH-SY5Y Cells

Acitretin is an oral drug approved by the Food and Drug Administration that is commonly used to treat psoriasis. In recent years, acitretin has been identified as a candidate drug for the treatment of Alzheimer's disease, but its role in neuronal development is still unclear. In this study, the human neuroblastoma cell line SH-SY5Y was used as a model to study neuronal differentiation. We found that acitretin effectively promoted the differentiation of SH-SY5Y cells into neuronal cells and upregulated the expression of the neuronal marker β-III tubulin and the mature neuronal marker NFH. Differentially expressed genes were identified by RNA sequencing and analyzed by bioinformatics approaches. The results showed that genes associated with neuron development-related pathways, such as SSPO and KCNT1, had significant changes in expression. Analysis showed that PRKCA and CAMK2B may play important roles in the process by which acitretin promotes neurodevelopment. Through whole-cell patch clamping and a microelectrode array assay, we found that acitretin-treated neurons generated electrical spikes similar to those generated by mature neurons. This study provided evidence to support an accessible and safe model of neuron-like cells and verified that acitretin can promote the differentiation of neurons and has the potential to treat brain tumors and neurodevelopmental and neurodegenerative diseases.

3,4-Dihydroxybenzalacetone Inhibits the Propagation of Hydrogen Peroxide-Induced Oxidative Effect via Secretory Components from SH-SY5Y Cells

The polyphenol derivative 3,4-dihydroxybenzalacetone (DBL) is the primary antioxidative component of the medicinal folk mushroom Chaga (Inonotus obliquus (persoon) Pilat). In this study, we investigated whether the antioxidative effect of DBL could propagate to recipient cells via secreted components, including extracellular vesicles (EVs), after pre-exposing SH-SY5Y human neuroblastoma cells to DBL. First, we prepared EV-enriched fractions via sucrose density gradient ultracentrifugation using conditioned medium from SH-SY5Y cells exposed to 100 µM hydrogen peroxide (H₂O₂) for 24 h, with and without 1 h of 5 µM DBL pre-treatment. CD63 immuno-dot blot analysis demonstrated that fractions with density of 1.06-1.09 g/cm³ had CD63-like immuno-reactivities. Furthermore, the 2,2-diphenyl-1-picrylhydrazyl assay revealed that the radical scavenging activity of fraction 11 (density of 1.06 g/cm³), prepared after 24-h H₂O₂ treatment, was significantly increased compared to that in the control group (no H₂O₂ treatment). Notably, 1 h of 5 µM DBL pre-treatment or 5 min of heat treatment (100 °C) diminished this effect, although concentrating the fraction by 100 kDa ultrafiltration enhanced it. Overall, the effect was not specific to the recipient cell types. In addition, the uptake of fluorescent Paul Karl Horan-labeled EVs in concentrated fraction 11 was detected in all treatment groups, particularly in the H₂O₂-treated group. The results suggest that cell-to-cell communication via bioactive substances, such as EVs, in conditioned SH-SY5Y cell medium, propagates the H₂O₂-induced radical scavenging effect, whereas pre-conditioning with DBL inhibits it.

Inhibition of p38 Mitogen-Activated Protein Kinases Attenuates Methylmercury Toxicity in SH-SY5Y Neuroblastoma Cells

Methylmercury (MeHg) is a toxic metal that causes irreversible damage to the nervous system, making it a risk factor for neuronal degeneration and diseases. MeHg activates various cell signaling pathways, particularly the mitogen-activated protein kinase (MAPK) cascades, which are believed to be important determinants of stress-induced cell fate. However, little is known about the signaling pathways that mitigate the neurotoxic effects of MeHg. Herein, we showed that pretreatment with a p38 MAPK-specific inhibitor, SB203580, attenuates MeHg toxicity in human neuroblastoma SH-SY5Y cells, whereas pretreatment with the extracellular signaling-regulated kinase inhibitor U0126 and the c-Jun N-terminal kinase inhibitor SP600125 does not. Specifically, we quantified the levels of intracellular mercury (Hg) and found that pretreatment with SB203580 reduced Hg levels compared to MeHg treatment alone. Further analysis showed that pretreatment with SB203580 increased multidrug resistance-associated protein 2 (MRP2) mRNA levels after MeHg treatment. These results indicate that detoxification of MeHg by p38 MAPK inhibitors may involve an efflux function of MeHg by inducing MRP2 expression.

The oxidative stress, mitochondrial pathway apoptosis, and the antagonistic effects of chrysophanol in SH-SY5Y cells via DTPP-induced photodynamic therapy

BACKGROUND

To investigate the susceptibility of SH-SY5Y cells to DTPP-based photodynamic therapy (PDT) and the antagonistic effects of chrysophanol (Chr) on PDT.

METHODS

PDT photocytotoxicity to cells was quantified and determined by exposing increasing concentrations of DTPP between 2.5 to 20 μg/mL to radiation with energy densities of 1.2-9.6 J/cm² at 630-nm wavelength. Sodium azide (SA, NaN₃) and d-mannitol (DM) were employed to study the reaction type of PDT. The photodynamic stress after PDT was assessed by superoxide dismutase (SOD), malondialdehyde (MDA), and total antioxidative capacity (T-AOC) assays. The apoptosis pathway of SH-SY5Y cells after PDT was studied by the determination of JC-1 and caspase-9/Caspase-3 concentrations. MTT and double fluorescence staining assays were applied to study the effect of Chr on cell survival and apoptosis rate in PDT, respectively. PI was used to detect the effect of Chr on cell membrane integrity after DTPP-PDT treatment.

RESULTS

The dose-dependent killing effect of high DTPP concentrations and irradiation doses were identified. Cell apoptosis is mediated by a mitochondrial pathway with a total apoptosis rate of 33.8% at 10 μg/mL of DTPP after irradiation with 2.4 J/cm². Oxidative stress was produced by ROS in PDT and non-reversible cell oxidative damage appeared due to the cells' modulation of the oxidative stress balance during the PDT response. Chr had a- effect on ROS capture and an inhibitory effect on the PDT-induced destruction of cell membranes.

CONCLUSIONS

SH-SY5Y cells were susceptible to DTPP-PDT, resulting in a mitochondrial apoptosis pathway. There is an antagonistic effect of Chr on PDT in SH-SY5Y neuroblastoma cells.

Neuroblastoma SH-SY5Y Cell Differentiation to Mature Neuron by AM580 Treatment

Neuroblastoma is a type of developmental childhood cancer that arises from the neural crest. It is the most common pediatric solid tumor in the world. AM580 is a powerful cyto-differentiating molecule on acute promyelocytic leukemia cells and induced pluripotent stem cells, but its effect on neuroblastoma is still unknown. In this study, the neuronal differentiation impact of AM580 was investigated using the human neuroblastoma cell line SH-SY5Y as a model. AM580 successfully stimulated the SH-SY5Y cells to develop into neuron-like cells. Functional enrichment analysis of RNAseq data revealed that differentially expressed genes (DEGs) were substantially enriched for GO keywords and KEGG pathways linked to neuron development. Some potassium ion channel genes associated with neuronal excitation, such as KCNT1, were shown to be upregulated. Through the MEA tests, we found the AM580-induced neurons possessed electrical spikes as mature neurons. AM580 also induced the neuronal marker β-tubulin III and mature neurons marker Neurofilament H. Our study proved that AM580 can promote the differentiation of neurons and has the potential to treat neuroblastoma, neurodevelopmental and neurodegenerative diseases.

Assessment of mechanism involved in the apoptotic and anti-cancer activity of Quercetin and Quercetin-loaded chitosan nanoparticles

In prior studies, Quercetin was revealed to exhibit anti-cancer features in a variety of cancer cell lines. However, the impact of Quercetin on neuroblastoma is unknown. This study looked into the potential cytotoxic effects of Quercetin and Quercetin-loaded chitosan nanoparticles (NPs) on the SH-SY5Y cell line. In this study, NPs containing Quercetin was prepared and characterization studies were performed. The vitality of the cells was measured using the XTT test after 24 h of treatment with various concentrations of Quercetin (0.5, 1, 2, 4, and 8 µg/mL). ELISA kits were used to detect the amounts of cleaved PARP, BCL-2, 8-Hydroxy-deoxyguanosine (8-oxo-dG), cleaved caspase 3, Bax, total oxidant status, and total antioxidant status in the cells. The results of the chitosan NPs characterization investigation revealed that the particle size, encapsulation effectiveness, and drug release profile of NPs were all appropriate for cell culture studies. Quercetin and Quercetin-loaded chitosan NPs significantly reduced cell viability in SH-SY5Y cells at different concentrations (**p < 0.05). 2 µg/mL Quercetin and Quercetin-loaded chitosan NPs significantly enhanced the levels of 8-oxo-dG, cleaved caspase 3, Bax, cleaved PARP, and total oxidant in ELISA testing. However, treatment with 2 µg/mL of Quercetin and Quercetin-loaded chitosan NPs did not affect the amount of BCL-2 protein. Overall, Quercetin and Quercetin-loaded chitosan NPs caused significant cytotoxicity in SH-SY5Y cells via producing oxidative stress, DNA damage, and eventually apoptosis.

Investigation of the mechanisms involved in anticancer effect of glucosamine sulfate on SH-SY5Y cell line

AIM

Glucosamine derivatives have been found to have anticancer effects in many cancer cell lines in previous investigations. The effect of glucosamine sulfate on neuroblastoma, however, is uncertain. The potential cytotoxic effects of glucosamine sulfate on the SH-SY5Y cell line were investigated in this study. The underlying mechanisms of this cytotoxicity have also been studied.

MATERIAL AND METHODS

In this study, the SH-SY5Y cell lines were used. The cells were treated with various concentrations of glucosamine sulfate (0.3125, 0.625, 1.25 and 2.5 μg/mL) and the viability of the cells was determined using the XTT assay after 24 hours. The quantities of cleaved PARP, BCL-2, 8-Hydroxy-desoxyguanosine (8-oxo-dG), cleaved caspase 3, Bax, total oxidant, and total antioxidant in the cells were determined by ELISA kits.

RESULTS

At doses of 0.3125, 0.625, 1.25 and 2.5 μg/mL, glucosamine sulfate dramatically reduced cell viability in SH-SY5Y cells (p<0.001). ELISA tests demonstrated that 1.25 μg/mL glucosamine sulfate considerably increased the amounts of 8-oxo-dG, cleaved caspase 3, Bax, cleaved PARP and total oxidant. However, 1.25 μg/mL glucosamine sulfate treatment did not change the quantity of BCL-2 protein.

CONCLUSIONS

Altogether, glucosamine sulfate produced considerable cytotoxicity in SH-SY5Y cells by triggering oxidative stress, inducing DNA damage, and finally causing apoptosis. In addition, more research is needed to determine the efficacy of glucosamine sulfate as an anticancer drug in the treatment of neuroblastoma (Fig. 5, Ref. 39).

PDGF-BB is involved in phosphate regulation via the phosphate transporters in human neuroblastoma SH-SY5Y cells

Inorganic phosphate (Pi) is the second most abundant inorganic ion in the body. Since abnormalities in Pi metabolism are risk factors for various diseases, serum Pi levels are strictly controlled. Type-III sodium-dependent Pi transporters, PiT-1 (encoded by SLC20A1) and PiT-2 (encoded by SLC20A2), are distributed throughout the tissues of the body, including the central nervous system, and are known to be responsible for extracellular to intracellular Pi transport. Platelet-derived growth factor (PDGF) is a major growth factor of mesenchymal cells. PDGF-BB, a homodimer of PDGF-B, regulates intracellular Pi by increasing PiT-1 expression in vascular smooth muscle cells. However, the effects of PDGF-BB on Pi transporters in neurons have yet to be reported. Here, we investigated the effect of PDGF-BB on Pi transporters in human neuroblastoma SH-SY5Y cells. PDGF-BB did not induce SLC20A1 mRNA expression, but it increased the intracellular uptake of Pi via PiT-1 in SH-SY5Y cells. Among the signaling pathways associated with PDGF-BB, AKT signaling was shown to be involved in the increase in Pi transport. In addition, the PDGF-BB-induced increase in Pi mediated neuroprotective effects in SLC20A2-suppressed cells, in an in vitro model of the pathological condition found in idiopathic basal ganglia calcification. Moreover, the increase in Pi uptake was found to occur through promotion of intracellular PiT-1 translocation to the plasma membrane. Overall, these results indicate that PDGF-BB exerts neuroprotective effects via Pi transport, and they demonstrate the potential utility of PDGF-BB against abnormal Pi metabolism in neurons.

Kaposi's sarcoma-associated herpesvirus infection promotes proliferation of SH-SY5Y cells by the Notch signaling pathway

Background

The cancer caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) infection is one of the major causes of death in AIDS patients. Some patients have neurological symptoms, which appear to be associated with KSHV infection, based on the neurotropic tendency of this virus in recent years. The objectives of this study were to investigate the effects of KSHV infection on neuronal SH-SY5Y cells and to identify differentially expressed genes.

Methods

KSHV was collected from islk.219 cells. Real-time PCR was used to quantify KSHV copy numbers. KSHV was used to infect SH-SY5Y cells. The KSHV copy number in the supernatants and mRNA levels of latency-associated nuclear antigen (LANA), ORF26, K8.1 A, and replication and transcriptional activator (RTA) were detected by real-time PCR. Proteins were detected by immunohistochemistry. The effect of KSHV infection on cell proliferation was detected by MTT and Ki-67 staining. Cell migration was evaluated by Transwell and wound healing assays. The cell cycle was analyzed by flow cytometry. The expression of CDK4, CDK5, CDK6, cyclin D1, and p27 were measured by western blotting. The levels of cell cycle proteins were re-examined in LANA-overexpressing SH-SY5Y cells. Transcriptome sequencing was used to identify differentially expressed genes in KSHV-infected cells. The levels of Notch signaling pathway proteins were measured by western blotting. RNA interference was used to silence Notch1 and proliferation were analyzed again.

Results

SH-SY5Y cells were successfully infected with KSHV, and they maintained the ability to produce virions. KSHV-infected SH-SY5Y expressed LANA, ORF26, K8.1 A, and RTA. After KSHV infection, cell proliferation was enhanced, but cell migration was suppressed. KSHV infection accelerated the G0/G1 phase. CDK4, CDK5, CDK6, and cyclin D1 expression was increased, whereas p27 expression was decreased. After LANA overexpression, CDK4, CDK6 and cyclin D1 expression was increased. Transcriptome sequencing showed that 11,258 genes were upregulated and 1,967 genes were downregulated in KSHV-infected SH-SY5Y. The Notch signaling pathway played a role in KSHV infection in SH-SY5Y, and western blots confirmed that Notch1, NICD, RBP-Jĸ and Hes1 expression was increased. After silencing of Notch1, the related proteins and cell proliferation ability were decreased.

Conclusions

KSHV infected SH-SY5Y cells and promoted the cell proliferation. KSHV infection increased the expression of Notch signaling pathway proteins, which may have been associated with the enhanced cell proliferation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02269-0.

Neuroprotective effect of bromelain in 6-hydroxydopamine induced in vitro model of Parkinson's disease

BACKGROUND

This study was designed to investigate the neuroprotective effects of bromelain, which is known to have anti-oxidant and anti-inflammatory properties, against the neurotoxicity (induced by 6-OHDA) in SH-SY5Y cells.

METHODS AND RESULTS

To establish Parkinson's Disease (PD) model in cell culture conditions, SH-SY5Y cells were exposed to 200 µM 6-OHDA for 1 day. Prior to 6-OHDA treatment, SH-SY5Y cells had been pre-treated with bromelain (25 µg/mL, 50 µg/mL, 75 µg/mL and 100 µg/mL). After 1 day, cell viability was determined with the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and lactate dehydrogenase (LDH) assays. Oxidative stress was assessed with total antioxidant capacity (TAC), total oxidant status (TOS), glutathione reductase (GR) and malondialdehyde (MDA) analyses. The effect of the bromelain in SH-SY5Ycells was also examined by 4',6-diamidino-2-phenylindole (DAPI) staining. We found that 6-OHDA increased LDH leakage, and cellular apoptosis in SH-SY5Y cells. 6-OHDA aggravated oxidative stress by increasing TOS, MDA and GR and eventually promoted apoptosis in SH-SY5Y cells, while pretreatment with bromelain attenuated these toxic effects of 6-OHDA.

CONCLUSIONS

These findings indicated that bromelain, with its neuroprotective features can be useful for neuroprotection in PD.

Protective role of selenium on MPP+ and homocysteine-induced TRPM2 channel activation in SH-SY5Y cells

Homocysteine is an intermediate product of biochemical reactions occurring in living organisms. It is known that drugs that increase dopamine synthesis used in Parkinson's disease (PD) cause an increase in the plasma homocysteine level. As the plasma homocysteine level increases, the amount of intracellular free calcium ion ([Ca²⁺]_i) and oxidative stress increase. As a result, it contributes to the excitotoxic effect by causing neurodegeneration. TRPM2 cation channel is activated by high [Ca²⁺]_i and oxidative stress. The role of TRPM2 in the development of neuronal damage due to the increase in homocysteine in PD has not yet been elucidated. In current study, we aimed to investigate the role of the TRPM2 and selenium (Se) in SH-SY5Y neuronal cells treated with homocysteine (HCT) and MPP . SH-SY5Y cells were divided into four groups: control, MPP, MPP + HCT, and MPP + HCT + Se. The results of plate reader assay, confocal microscope imaging, and western blot analyses indicated upregulation of apoptosis, [Ca²⁺]_i, mitochondrial membrane depolarization, caspase activation, and intracellular ROS values in the cells. The MPP + HCT group had considerably higher values than the other groups. The MPP + HCT + Se group had significantly lower values than all the other groups except the control group. In addition, incubation of MPP + HCT and MPP + HCT + Se groups with TRPM2 antagonist 2-APB increased cell viability and reduced intracellular calcium influx and apoptosis levels. It is concluded that the activation of TRPM2 was propagated in HCT and MPP-induced SH-SY5Y cells by the increase of oxidative stress. The antioxidant property of Se regulated the TRPM2 channel activation and neurodegeneration by providing intracellular oxidant/antioxidant balance.

[Mechanism of puerarin reversing SH-SY5Y cell injury induced by Aβ_(1-42) based on proteomics]

Puerarin has the anti-Alzheimer&apos;s disease (AD) activity,which can reverse nerve injury induced by Aβand inhibit neuronal apoptosis.However,its potential pharmacodynamic mechanism still needs to be further researched.The occurrence and development of AD is due to the change of multiple metabolic links in the body,which leads to the destruction of balance.Puerarin may act on multiple targets and multiple metabolic processes to achieve therapeutic purposes.Quantitative proteomic analysis provides a new choice to understand the mechanism as completely as possible.This research adopted SH-SY5Y cells induced by Aβ_(1-42)to establish AD cell model,and Aβimmunofluorescence detection showed that Aβdecreased significantly after puerarin intervention.The mechanism of puerarin reversing SH-SY5Y cell injured by Aβ_(1-42)was further explored by using label-free non-labeled quantitative technology and Western blot detection based on bioinformatics analysis result.The results showed that most of the differential proteins were related to biological processes such as cellular component organization or biogenesis,cellular component organization and cellular component biogenesis,and they mainly participated in the top ten pathways of P value such as pathogenic Escherichia coli infection,m TOR signaling pathway,regulation of autophagy,regulation of actin cytoskeleton,spliceosome,hepatocellular carcinoma,tight junction,non-small cell lung cancer,apoptosis and gap junction.Annexin V/PI flow cytometry and TUNEL were used to detect apoptosis,and the results showed that Aβdecreased significantly and the rate of apoptosis decreased significantly after puerarin intervention.Western blot analysis found that the protein expression level of autophagy related protein LC3Ⅱwas up-regulated after Aβinduction,and the degree of this up-regulation was further enhanced in puerarin intervention group.The trend of the ratio of LC3Ⅱ/LC3Ⅰamong groups was the same as the protein expression level of LC3Ⅱ，the protein expression level of p62 in the control group,AD model group and puerarin intervention group decreased successively.Protein interaction network analysis showed that CAP1 was correlated with TUBA1B,HSP90AB2P,DNM1L,TUBA1A and ERK1/2,and the correlation between CAP1 and ERK1/2 was the highest among them.Western blot showed that the expressions of p-ERK1/2,Bax and CAP1 were significantly down-regulated and the protein expression level of Bcl-2 was significantly up-regulated after puerarin intervention.Therefore,puerarin might improve the SH-SY5Y cells injured by Aβ_(1-42)through the interaction of multiple biological processes and pathways in cells multiple locations,and CAP1 might play an important role among them.

Estradiol exerts a neuroprotective effect on SH-SY5Y cells through the miR-106b-5p/TXNIP axis

Alzheimer's disease (AD) is a neurodegenerative disease. Thioredoxin and thioredoxin-interacting protein (TXNIP) complexes help sustain cell oxidation/reduction balance. In the present study, we verified the neuroprotective role of estradiol against amyloid-beta 42 in SH-SY5Y cells through inhibiting TXNIP expression, promoting cell viability and DNA synthesis ability, inhibiting cell apoptosis, and affecting caspase and Bax/Bcl-2 apoptotic signaling. miR-106b-5p could bind to TXNIP 3'-untranslated region to inhibit the expression level of TXNIP. Within SH-SY5Y cells, miR-106b-5p inhibition repressed cell viability and DNA synthesis ability and promoted cell apoptosis through caspase and Bax/Bcl-2 apoptotic signaling, while miR-106b-5p overexpression or TXNIP knockdown exerted the opposite effects on SH-SY5Y cells; TXNIP knockdown remarkably attenuated the roles of miR-106b-5p inhibition. In conclusion, estradiol treatment on SH-SY5Y cells downregulates TXNIP expression and upregulates miR-106b-5p expression. miR-106b-5p exerts a neuroprotective effect on SH-SY5Y cells by promoting cell proliferation and inhibiting cell apoptosis through targeting TXNIP.

SOX21-AS1 modulates neuronal injury of MMP+-treated SH-SY5Y cells via targeting miR-7-5p and inhibiting IRS2

Parkinson's disease (PD), caused by the decreased number of dopaminergic neurons in the substantia nigra, is identified as the second most familiar age-dependent neurodegenerative disease to the public. Long non-coding RNAs (lncRNAs) have been reported to participate in the development of PD. In our research, the expression of lncRNA SRY-box transcription factor 21 antisense divergent transcript 1 (SOX21-AS1) was up-regulated in 1-methyl-4-phenylpyridinium (MMP⁺)-treated SH-SY5Y cells. In addition, SOX21-AS1 depletion weakened the cell injury induced by MMP⁺. Moreover, SOX21-AS1 knockdown decreased Reactive Oxygen Species (ROS) generation and levels of TNF-α, IL-1β and IL-6, but increased SOD activity. However, SOX21-AS1 up-regulation led to opposite results. Further, SOX21-AS1 could bind with miR-7-5p, whose overexpression relieved MMP⁺-induced cell injury. Additionally, insulin receptor substrate 2 (IRS2) served as the target gene of miR-7-5p, and its expression was positively modulated by SOX21-AS1. Similarly, IRS2 knockdown also had alleviative effects on cell injury stimulated by MMP⁺ treatment. In sum up, our study demonstrated a new regulatory network consisted of SOX21-AS1, miR-7-5p and IRS2 in SH-SY5Y cells, supplying with a better comprehension about the pathogenic mechanism of PD.

Low Levels of Brain-Derived Neurotrophic Factor Trigger Self-aggregated Amyloid β-Induced Neuronal Cell Death in an Alzheimer's Cell Model

Alzheimer's disease (AD) is pathologically characterized by accumulation of amyloid β (Aβ) and hyperphosphorylated tau, and thereby induction of neuronal cell death. The Aβ-induced neuronal cell death has been shown to occur by several modes, such as apoptosis, necrosis, and necroptosis. Interestingly, in AD patients, the brain and serum levels of brain-derived neurotrophic factor (BDNF) have been reported to be significantly decreased. However, the relationship between Aβ and BDNF in the onset of AD remains to be fully understood. Here, we used neuron-like differentiated human neuroblastoma SH-SY5Y (ndSH-SY5Y) cells to study the neurotoxicity of self-aggregated Aβ_1-42 peptide under different concentrations of BDNF in the culture medium. Importantly, decreasing levels of BDNF caused a considerable suppression in the extension of neurite length. Furthermore, only under low levels of BDNF, the aggregated Aβ was revealed to induce neurite fragmentation and neuronal cell death in ndSH-SY5Y cells. Notably, the aggregated Aβ and low levels of BDNF-induced neuronal cell death was characterized at least as caspase-6 dependent cell death and necroptosis. These results indicate that our ndSH-SY5Y cell system, cultured under decreasing levels of BDNF and aggregated Aβ, has the potential to be applied in the analysis of the molecular mechanisms of the progressive neurodegenerative processes of AD and the discovery of neuroprotective drug candidates.

[Autophagic dysfunction contributes to α-synuclein accumulation in dopaminergic neurons induced by paraquat]

Objective: To investigate the effects of Paraquat on autophagy level in SH-SY5Y cell and the mechanism of abnormal aggregation of α-synuclein. Methods: Human neuroblastoma cell (SH-SY5Y cell) was used as model of dopaminergic neurons in vitro. The cells were treated with different concentrations of PQ (0, 18.75, 37.5, 75, 150, 300, 600 μmol/L) for 24 hours, and induced by 150 μmol/L PQ for 0, 12, 24, 36, 48, 60, 72, 96 hours to detect the relative survival rate of cells and determine dose/time-effect relationship. The cells were treated with concentration of 0, 75, 150, 300, 600 μmol/L PQ for 24 hours, and induced by 150 μmol/L PQ for different hours to detect intracellular LDH activity. The expression levels of autophagy-related proteins(LC3I, LC3II, Beclin1 , Vps34 and p62) and α-synuclein were detected by Western blot. The gene expression level of α-synuclein was assayed by Real-time quantitative PCR. The expression level of α-synuclein was also evaluated by immunofluorescence. The cells were pretreated with 100 nmol/L autophagy inducer rapamycin (RAPA) for 6 hours. The expression levels of autophagy-related proteins and α-synuclein were detected by Western blot. Results: CCK8 assay showed PQ induced cell survival rate decrease in a time and dose dependent manner; Compared with control group, the activity of LDH in the cell supernatant increased significantly after PQ exposure (P<0.05) ; Western blot analysis showed the ratio of autophagy-related protein LC3II/LC3I, Beclin1 and Vps34 protein expression were significantly lower after PQ treatment while the expression of p62 protein was higher (P<0.05) ; The protein and gene expression of α-synuclein were increased significantly after PQ treatment (P <0.05) ; Immunofluorescence showed the fluorescence intensity of α- synuclein in cells was significantly enhanced (P <0.05) . Compared with PQ group, the expression levels of autophagy-related proteins LC3II/LC3I and Beclin1 were significantly increased whlie α-synuclein protein level was decreased after RAPA induction (P<0.05) . Similarly, the IF result showed the fluorescence signal of α- synuclein significantly decreased after RAPA induction (P<0.05) . Conclusion: Paraquat induced autophagy dysfunction in SH-SY5Y cells, which leads to an abnormal aggregation of α-synuclein.

Maackiain Ameliorates 6-Hydroxydopamine and SNCA Pathologies by Modulating the PINK1/Parkin Pathway in Models of Parkinson's Disease in Caenorhabditis elegans and the SH-SY5Y Cell Line

The movement disorder Parkinson's disease (PD) is the second most frequently diagnosed neurodegenerative disease, and is associated with aging, the environment, and genetic factors. The intracellular aggregation of α-synuclein and the loss of dopaminergic neurons in the substantia nigra pars compacta are the pathological hallmark of PD. At present, there is no successful treatment for PD. Maackiain (MK) is a flavonoid extracted from dried roots of Sophora flavescens Aiton. MK has emerged as a novel agent for PD treatment that acts by inhibiting monoamine oxidase B. In this study, we assessed the neuroprotective potential of MK in Caenorhabditis elegans and investigated possible mechanism of this neuroprotection in the human SH-SY5Y cell line. We found that MK significantly reduced dopaminergic neuron damage in 6-hydroxydopamine (6-OHDA)-exposed worms of the BZ555 strain, with corresponding improvements in food-sensing behavior and life-span. In transgenic worms of strain NL5901 treated with 0.25 mM MK, the accumulation of α-synuclein was diminished by 27% (p < 0.01) compared with that in untreated worms. Moreover, in worms and the SH-SY5Y cell line, we confirmed that the mechanism of MK-mediated protection against PD pathology may include blocking apoptosis, enhancing the ubiquitin-proteasome system, and augmenting autophagy by increasing PINK1/parkin expression. The use of small interfering RNA to downregulate parkin expression in vivo and in vitro could reverse the benefits of MK in PD models. MK may have considerable therapeutic applications in PD.

Synthesis of Novel Baicalein Amino Acid Derivatives and Biological Evaluation as Neuroprotective Agents

Baicalein, a famously effective component of the traditional Chinese medicine Rhizoma Huang Qin (Scutellaria altissima L.), has been proved to have potent neuroprotection and anti-platelet aggregation effects with few side effects. Meanwhile, recent studies have revealed that the introduction of amino acid to baicalein could improve its neuroprotective activity. In the present study, a series of novel baicalein amino acid derivatives were designed, synthesized, and screened for their neuroprotective effect against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells and toxicity on the normal H9C2 cell line by standard methylthiazol tetrazolium (MTT) assay. In addition, all of the newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, and high resolution mass spectrometry (HR-MS). The results showed that most of the compounds provided more potent neuroprotection than baicalein, and were equivalent to the positive drug edaravin. They showed no obvious cytotoxicity on normal H9C2 cells. Notably, the most active compound 8 displayed the highest protective effect (50% effective concentration (EC₅₀) = 4.31 μM) against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells, which was much better than the baicalein (EC₅₀ = 24.77 μM) and edaravin (EC₅₀ = 5.62 μM). Further research on the chick chorioallantoic membrane (CAM) model indicated that compound 8 could significantly increase angiogenesis, which might promote neurovascular proliferation. The detection of apoptosis analysis showed that compound 8 could dramatically alleviate morphological manifestations of cell damage. Moreover, the benzyloxycarbonyl (cbz)-protected baicalein amino acid derivatives showed better neuroprotective activity than the t-Butyloxy carbonyl (boc)-protected derivatives.

Comparative analysis of in vitro neurotoxicity of methylmercury, mercury, cadmium, and hydrogen peroxide on SH-SY5Y cells

Mercury (Hg) and cadmium (Cd) are the major toxic heavy metals and are known to induce neurotoxicity. Although many studies have shown that several heavy metals have neurotoxic effects, the cellular and molecular mechanisms thereof are still not clear. Oxidative stress is reported to be a common and important mechanism in cytotoxicity induced by heavy metals. However, the assays for identifying toxic mechanisms were not performed under the same experimental conditions, making it difficult to compare toxic properties of the heavy metals. In this study, we investigated the mechanisms underlying neurotoxicity induced by heavy metals and H₂O₂, focusing on cell death, cell proliferation, and oxidative stress under the same experimental condition. Our results showed that MeHg caused lactate dehydrogenase (LDH) release, caspase activation and cell-cycle alteration, and ROS generation in accordance with decreased cell viability. HgCl₂ caused LDH release and cell-cycle alteration, but not caspase activation. CdCl₂ had a remarkable effect on the cell cycle profiles without induction of LDH release, caspase activation, or ROS generation. Pretreatment with N-acetyl-l-cysteine (NAC) prevented the decrease in cell viability induced by MeHg and HgCl₂, but not CdCl₂. Our results demonstrate a clear difference in neurotoxic mechanisms induced by MeHg, HgCl₂, CdCl₂ or H₂O₂ in SH-SY5Y cells. Elucidating the characteristics and mechanisms of each heavy metal under the same experimental conditions will be helpful to understand the effect of heavy metals on health and to develop a more effective therapy for heavy metal poisoning.

[Effect of Ginkgo biloba extract (EGb50) on mitochondrial function in SH-SY5Y cells after hypoxia/reoxygenation injury]

Ischemic cerebrovascular disease and cerebral ischemia/reperfusion injury threaten the health of human being. We studied the protective effect of Ginkgo biloba extract 50 (EGb50) on the mitochondrial function in SH-SY5Y cells after hypoxia/reoxygenation (H/R) injury and explored its mechanisms, so as to provide new ideas for studies on the treatment for ischemic cerebrovascular disease. We established the H/R injury model in SH-SY5Y cells after administrating EGb50. Subsequently, the mitochondrial membrane potential and the concentration of intracellular Ca²⁺ were measured by flow cytometer. The levels of optic atrophy1 (Opa1) and dynamin-like protein 1 (Drp1) were evaluated by immunofluorescence and western blot. The results showed that the mitochondrial membrane potential was decreased and the level of intracellular Ca²⁺ was increased after H/R injury. Moreover, the expression of mitochondrial fusion protein Opa1 was decreased, while the expression of mitochondrial fission protein Drp1 was increased. However, EGb50 significantly increased the mitochondrial membrane potential and suppressed the level of intracellular Ca²⁺. In addition, EGb50 increased the expression of Opa1 and decreased the expression of Drp1. The results demonstrated that EGb50 has a neuroprotective effect on SH-SY5Y cells after H/R injury, and could improve the energy metabolism and mitochondrial function. The underlying mechanisms may be associated with the regulation of mitochondrial fusion and fission, which provided data support for the treatment of ischemic cerebrovascular disease with EGb50.

Anthocyanins Extracted from Aronia melanocarpa Protect SH-SY5Y Cells against Amyloid-beta (1-42)-Induced Apoptosis by Regulating Ca2+ Homeostasis and Inhibiting Mitochondrial Dysfunction

We investigated the cytoprotective effects of anthocyanins in Aronia melanocarpa against apoptosis induced by Aβ_1-42, a key mediator of AD pathophysiology. We measured intracellular calcium with a colorimetric kit, cellular apoptosis with DAPI, intracellular ROS with the fluorescent marker 2,3-dimethoxy-1,4-naphthoquinone, mitochondrial membrane potential with JC-1, and ATP with a colorimetric kit. Gene transcription and protein expression levels of calmodulin, cytochrome c, caspase-9, cleaved caspase-3, Bcl-2, and Bax were analyzed by RT-PCR and Western blotting. The results showed that pretreatment with anthocyanins significantly inhibited Aβ_1-42-induced apoptosis, decreased intracellular calcium and ROS, and increased ATP and mitochondrial membrane potential. RT-PCR and Western blotting revealed that anthocyanins upregulated the gene transcription and protein expression of calmodulin and Bcl-2 and downregulated those of cytochrome c, caspase-9, cleaved caspase-3, and Bax. A. melanocarpa anthocyanins protected SH-SY5Y cells against Aβ_1-42-induced apoptosis by regulating Ca²⁺ homeostasis and apoptosis-related genes and inhibiting mitochondrial dysfunction.

Melatonin inhibits rotenone-induced SH-SY5Y cell death via the downregulation of Dynamin-Related Protein 1 expression

Previous studies have shown that melatonin can protect cells against rotenone-induced cell death. Yet, the mechanism involved in this protection requires further research. In this study, we aimed to further investigate the effects of melatonin on inhibiting rotenone-induced SH-SY5Y cells and the underlying molecular mechanisms. Human neuroblastoma SH-SY5Y cells were treated with 0.3 or 1μM rotenone for 6 or 12h. Cell viability was measured with an MTS assay, the mitochondrial membrane potential was determined with a Rhodamine 123 staining assay, and the protein expression levels of the markers of autophagy, including cytochrome C release (Cyt C), light chain 3B (LC3 B) and Dynamin-Related Protein 1 (Drp1) were analyzed by western blotting. The co-localization of Drp1 and TOM20 proteins in the mitochondria of SH-SY5Y cells was measured by immunofluorescence coupled with confocal microscopy and the overexpression of the Drp1 gene was then conducted. The viability and expression levels of Cyt C and LC3 B in rotenone and melatonin + rotenone-treated Drp1-overexpressed SH-SY5Y cells were analyzed with MTS and western blotting, respectively. We found that rotenone effectively induced SH-SY5Y cell death by causing mitochondrial dysfunction and increasing Cyt C expression. Drp1 expression and its regulation of mitochondrial translocation mediated the rotenone-induced cell death and melatonin inhibited this process. Overexpression of Drp1 protein attenuated melatonin's inhibition of rotenone-induced SH-SY5Y cell death. In conclusion, melatonin effectively inhibits rotenone-induced neuronal cell death via the regulation of Drp1 expression.

Protective effects of β-sheet breaker α/β-hybrid peptide against amyloid β-induced neuronal apoptosis in vitro

Alzheimer's disease is most common neurodegenerative disorder and is characterized by increased production of soluble amyloid-β oligomers, the main toxic species predominantly formed from aggregation of monomeric amyloid-β (Aβ). Increased production of Aβ invokes a cascade of oxidative damages to neurons and eventually leads to neuronal death. This study was aimed to investigate the neuroprotective effects of a β-sheet breaker α/β-hybrid peptide (BSBHp) and the underlying mechanisms against Aβ₄₀ -induced neurotoxicity in human neuroblastoma SH-SY5Y cells. Cells were pretreated with the peptide Aβ₄₀ to induce neurotoxicity. Assays for cell viability, cell membrane damage, cellular apoptosis, generation of reactive oxygen species (ROS), intracellular free Ca²⁺ , and key apoptotic protein levels were performed in vitro. Our results showed that pretreatment with BSBHp significantly attenuates Aβ₄₀ -induced toxicity by retaining cell viability, suppressing generation of ROS, Ca²⁺ levels, and effectively protects neuronal apoptosis by suppressing pro-apoptotic protein Bax and up-regulating antiapoptotic protein Bcl-2. These results suggest that α/β-hybrid peptide has neuroprotective effects against Aβ₄₀ -induced oxidative stress, which might be a potential therapeutic agent for treating or preventing neurodegenerative diseases.

Component analysis and target cell-based neuroactivity screening of Panax ginseng by ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry

Ginseng is one of the most widely used natural medicines in the world. Recent studies have suggested Panax ginseng has a wide range of beneficial effects on aging, central nervous system disorders, and neurodegenerative diseases. However, knowledge about the specific bioactive components of ginseng is still limited. This work aimed to screen for the bioactive components in Panax ginseng that act against neurodegenerative diseases, using the target cell-based bioactivity screening method. Firstly, component analysis of Panax ginseng extracts was performed by UPLC-QTOF-MS, and a total of 54 compounds in white ginseng were characterized and identified according to the retention behaviors, accurate MW, MS characteristics, parent nucleus, aglycones, side chains, and literature data. Then target cell-based bioactivity screening method was developed to predict the candidate compounds in ginseng with SH-SY5Y cells. Four ginsenosides, Rg2, Rh1, Ro, and Rd, were observed to be active. The target cell-based bioactivity screening method coupled with UPLC-QTOF-MS technique has suitable sensitivity and it can be used as a screening tool for low content bioactive constituents in natural products.

Design and synthesis of new piperidone grafted acetylcholinesterase inhibitors

Alzheimer's disease (AD) is a neurodegenerative disorder affecting 35million people worldwide. A common strategy to improve the well-being of AD patients consists on the inhibition of acetylcholinesterase with the concomitant increase of the neurotransmitter acetylcholine at cholinergic synapses. Two series of unreported N-benzylpiperidines 5(a-h) and thiazolopyrimidines 9(a-q) molecules were synthesized and evaluated in vitro for their acetylcholinesterase (AChE) inhibitory activities. Among the newly synthesized compounds, 5h, 9h, 9j, and 9p displayed higher AChE enzyme inhibitory activities than the standard drug, galantamine, with IC₅₀ values of 0.83, 0.98, and 0.73μM, respectively. Cytotoxicity studies of 5h, 9h, 9j, 9n and 9p on human neuroblastoma cells SH-SY5Y, showed no toxicity up to 40μM concentration. Molecular docking simulations of the active compounds 5h and 9p disclosed the crucial role of π-π-stacking in their binding interaction to the active site AChE enzyme. The presented compounds have potential as AChE inhibitors and potential AD drugs.

Chemical constituents of Narcissus tazetta var. chinensis and their antioxidant activities

Two new flavan derivatives tazettones C-D (1-2), one new β-coumaranone (tazettone E, 3), one new flavan (tazettone F, 4), and one new phenylpropanoid (tazettone G, 5), together with six known flavonoids (6-11), were isolated from the bulbs of Narcissus tazetta var. chinensis Roem. Their structures were elucidated by spectroscopic analysis. In addition, the structures of 1-3 were confirmed by single crystal X-ray diffraction. All isolated compounds were tested for antioxidant activity by Cell Counting Kit-8 (CCK-8) assay. Compounds 6-8 and 10-11 exhibited potent antioxidant activity against H2O2-induced impairment in human SH-SY5Y neuroblastoma cells at tested concentrations.

Water-soluble fractions from defatted sesame seeds protect human neuroblast cells against peroxyl radicals and hydrogen peroxide-induced oxidative stress

Oxidative stress is involved in the development of aging-related diseases, such as neurodegenerative diseases. Dietary antioxidants that can protect neuronal cells from oxidative damage play an important role in preventing such diseases. Previously, we reported that water-soluble fractions purified from defatted sesame seed flour exhibit good antioxidant activity in vitro. In the present study, we investigated the protective effects of white and gold sesame seed water-soluble fractions (WS-wsf and GS-wsf, respectively) against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H2O2) induced oxidative stress in human neuroblast SH-SY5Y cells. Pretreatment with WS-wsf and GS-wsf did not protect cells against AAPH-induced cytotoxicity, while simultaneous co-treatment with AAPH significantly improved cell viability and inhibited membrane lipid peroxidation. These results suggest that WS-wsf and GS-wsf protect cells from AAPH-induced extracellular oxidative damage via direct scavenging of peroxyl radicals. When oxidative stress was induced by H2O2, pretreatment WS-wsf and GS-wsf significantly enhanced cell viability. These results suggest that in addition to radical scavenging, WS-wsf and GS-wsf enhance cellular resistance to intracellular oxidative stress by activation of the Nrf-2/ARE pathway as confirmed by the increased Nrf2 protein level in the nucleus and increased heme oxygenase 1 (HO-1) mRNA expression. The roles of ferulic and vanillic acids as bioactive antioxidants in these fractions were also confirmed. In conclusion, our results indicated that WS-wsf and GS-wsf, which showed antioxidant activity in vitro, are also efficient antioxidants in a cell system protecting SH-SY5Y cells against both extracellular and intracellular oxidative stress.

PINK1/Parkin-mediated mitophagy play a protective role in manganese induced apoptosis in SH-SY5Y cells

Manganese (Mn) as an environmental risk factor of Parkinson's disease (PD) is considered to cause manganism. Mitophagy is thought to play a key role in elimination the injured mitochondria. The goal of this paper was to explore whether the PINK1/Parkin-mediated mitophagy is activated and its role in Mn-induced mitochondrial dysfunction and cell death in SH-SY5Y cells. Here, we investigated effects of MnCl2 on ROS generation, mitochondrial membrane potential (MMP/ΔΨm) and apoptosis by FACS and examined PINK1/Parkin-mediated mitophagy by western-blotting and the co-localization of mitochondria and acidic lysosomes. Further, we explore the role of mitophagy in Mn-induced apoptosis by inhibition the mitophagy by knockdown Parkin level. Results show that MnCl2 dose-dependently caused ΔΨm decrease, ROS generation and apoptosis of dopaminergic SH-SY5Y cells. Moreover, Mn could induce mitophagy and PINK1/Parkin-mediated pathway was activated in SH-SY5Y cells. Transient transfection of Parkin siRNA knockdown the expressing level of parkin inhibited Mn-induced mitophagy and aggravated apoptosis of SH-SY5Y cells. In conclusion, our study demonstrated that Mn may induce PINK1/Parkin-mediated mitophagy, which may exert significant neuro-protective effect against Mn-induced dopaminergic neuronal cells apoptosis.

Structure-Activity Relationship Study of the Neuritogenic Potential of the Glycan of Starfish Ganglioside LLG-3 (‡)

LLG-3 is a ganglioside isolated from the starfish Linchia laevigata. To clarify the structure-activity relationship of the glycan of LLG-3 toward rat pheochromocytoma PC12 cells in the presence of nerve growth factor, a series of mono- to tetrasaccharide glycan derivatives were chemically synthesized and evaluated in vitro. The methyl group at C8 of the terminal sialic acid residue was crucial for neuritogenic activity, and the terminal trisaccharide moiety was the minimum active motif. Furthermore, the trisaccharide also stimulated neuritogenesis in human neuroblastoma SH-SY5Y cells via mitogen-activated protein kinase (MAPK) signaling. Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was rapidly induced by adding 1 or 10 nM of the trisaccharide. The ratio of phosphorylated ERK to ERK reached a maximum 5 min after stimulation, and then decreased gradually. However, the trisaccharide did not induce significant Akt phosphorylation. These effects were abolished by pretreatment with the MAPK inhibitor U0126, which inhibits enzymes MEK1 and MEK2. In addition, U0126 inhibited the phosphorylation of ERK 1/2 in response to the trisaccharide dose-dependently. Therefore, we concluded that the trisaccharide promotes neurite extension in SH-SY5Y cells via MAPK/ERK signaling, not Akt signaling.

Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIβ pathway

Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIβ (TopoIIβ), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIβ expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80μM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin βIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIβ, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIβ gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIβ expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIβ signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIβ in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system.

Glial U87 cells protect neuronal SH-SY5Y cells from indirect effect of radiation by reducing oxidative stress and apoptosis

Recent studies have demonstrated the role of indirect effect of radiation in neurodegeneration. However, the role of glial cells in neuroprotection against indirect effect of radiation is still not clear, although they are known to protect neurons under stress conditions in central nervous system. Our study showed that indirect effect of radiation increased the oxidative stress that further enhances the expression of key apoptotic proteins and leads to neuronal cell death. We also investigated the indirect effect of radiation on neuronal cells in the presence of glial cells in a transwell co-culture system, while our analysis was focused on neuronal cells. Irradiated cell-conditioned medium (ICCM) was used as source of indirect radiation and neuroprotective effect was analyzed by various endpoints. It was observed that ICCM-induced reactive oxidative species level was significantly reduced in SH-SY5Y cells co-cultured with glial U87 cells, which might help to maintain the integrity of mitochondrial membrane potential. Increased levels of antioxidant enzyme superoxide dismutase and antioxidant glutathione were observed in SH-SY5Y cells co-cultured with glial U87 cells. Moreover, it was also observed that co-culture with glial cells inhibits the expression of ICCM-induced apoptotic proteins, i.e. Bax, cytochrome c, and caspase-3 in SH-SY5Y cells. Hence, it can be speculated that in co-culture system glial cells may protect the neuronal SH-SY5Y cells by reducing the ICCM-induced oxidative stress and apoptotic death.

ATP13A2/PARK9 Deficiency Neither Cause Lysosomal Impairment Nor Alter α-Synuclein Metabolism in SH-SY5Y Cells

Parkinson's disease is a multifactorial disorder with several genes linked to the familial types of the disease. ATP13A2 is one of those genes and encode for a transmembrane protein localized in lysosomes and late endosomes. Previous studies suggested the roles of this protein in lysosomal functions and cellular ion homeostasis. Here, we set out to investigate the role of ATP13A2 in lysosomal function and in metabolism of α-synuclein, another PD-linked protein whose accumulation is implicated in the pathogenesis. We generated non-sense mutations in both copies of ATP13A2 gene in SH-SY5Y human neuroblastoma cells. We examined lysosomal function of ATP13A2-/- cells by measuring the accumulation of lysosomal substrate proteins, such as p62 and polyubiquitinated proteins, induction of acidic compartments, and degradation of ectopically introduced dextran. None of these measures were altered by ATP13A2 deficiency. The steady-state levels of α-synuclein in cells or secretion of this protein were unaltered either in ATP13A2-/- compared to the normal cells. Therefore, the proposed roles of ATP13A2 in lysosomal functions may not be generalized and may depend on the cellular context. The ATP13A2-/- cells generated in the current study may provide a useful control for studies on the roles of PD genes in lysosomal functions.

Anti-neurotoxicity effects of oxoisoaporphine-lipoic acid hybrids

Four oxoisoaporphine-lipoic acid hybrids were designed, synthesized, and investigated in this study. To develop the hybrids, the oxoisoaporphine fragment was used for its inhibition of cholinesterases and β-amyloid (Aβ) aggregation, while the unit of lipoic acid was used for its radical-capturing and neuroprotective effects. The hybrids exhibited moderate inhibitory effects on the activity of acetylcholinesterase (AChE), with IC50 values in the micromolar range and low toxicity in SH-SY5Y cells. Moreover, the learning and memory abilities, climbing capability, and average life expectancy of the Aβ42 transgenic Drosophila were all significantly improved by the hybrids. They also enhanced the intracephalic antioxidant activity, the metabolism, and the activity cholinesterase in the flies. More strikingly, Aβ42 aggregation in the hybrids-treated Drosophila was attenuated with effective neuroprotection. Our results indicate the potential of using these oxoisoaporphine-lipoic acid hybrids in AD treatments.

Nanomolar concentration of alpha-synuclein enhances dopaminergic neuronal survival via Akt pathway

Although alpha-synuclein is generally thought to have a pathological role in Parkinson's disease, accumulative evidence exists that alpha-synuclein has a neuroprotective effect. The aim of this study was to evaluate the effect of extracellular alpha-synuclein on dopaminergic cell survival. We assessed cell viability using the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltertazolium bromide (MTT) assay both in undifferentiated SH-SY5Y (SHSY) cells and neuronally-differentiated SH-SY5Y (ndSHSY) cells after 24 hour treatment with monomeric alpha-synuclein at various concentrations (0 [control], 50, 100 nmol/L, 1 μmol/L). To determine whether cell viability assessed by MTT assay was affected by cell proliferation, 5-bromo-2’-deoxyuridine (BrdU) incorporation assay was performed. Level of both Akt and phosphorylated Akt was measured using western blot method in ndSHSY cells with or without 24 hour alpha-synuclein treatment. Cell viability was increased in ndSHSY cells at the nanomolar concentration of alpha-synuclein, but not in SHSY cells. Proportion of BrdU-positive ndSHSY cells was decreased in alpha-synuclein-treated group compared with control group. Level of phosphorylated Akt in alpha-synuclein-treated group was higher compared with the control group. Our study shows that extracellular alpha-synuclein at nanomolar concentration benefits dopaminergic cell survival via Akt pathway.

PDYN, a gene implicated in brain/mental disorders, is targeted by REST in the adult human brain

The dynorphin κ-opioid receptor system is implicated in mental health and brain/mental disorders. However, despite accumulating evidence that PDYN and/or dynorphin peptide expression is altered in the brain of individuals with brain/mental disorders, little is known about transcriptional control of PDYN in humans. In the present study, we show that PDYN is targeted by the transcription factor REST in human neuroblastoma SH-SY5Y cells and that that interfering with REST activity increases PDYN expression in these cells. We also show that REST binding to PDYN is reduced in the adult human brain compared to SH-SY5Y cells, which coincides with higher PDYN expression. This may be related to MIR-9 mediated down-regulation of REST as suggested by a strong inverse correlation between REST and MIR-9 expression. Our results suggest that REST represses PDYN expression in SH-SY5Y cells and the adult human brain and may have implications for mental health and brain/mental disorders.

Protective effect of tomatine against hydrogen peroxide-induced neurotoxicity in neuroblastoma (SH-SY5Y) cells

OBJECTIVES

Reactive oxygen species can induce cell apoptosis, and oxidative stress has been implicated in a variety of neurodegenerative disorders. Tomatine, which is a naturally occurring steroidal glycoalkaloid isolated from Solanum cathayanum, has shown potent anti-oxidant properties.

METHODS

In this study, we used the SH-SY5Y cell line as an in vitro model and investigated the protective effect of tomatine against hydrogen peroxide (H2 O2 )-induced neurotoxicity in SH-SY5Y cells.

KEY FINDINGS

Tomatine might inhibit the release of cellular lactate dehydrogenase, increase anti-oxidant enzyme activity and glutathione content, reverse the downregulated protein expression of the brain-derived neurotrophic factor (BDNF), inhibit expression of Bax and activations of caspase-3 and caspase-9 in H2 O2 -induced SH-SY5Y cells.

CONCLUSIONS

Tomatine exerted beneficially neuroprotective effect on H2 O2 -induced SH-SY5Y cells, mainly enhancing intracellular anti-oxidant enzyme activity and BDNF expression, inhibiting H2 O2 -induced oxidative stress as well as expression of Bax and activations of caspase-3 and caspase-9, alleviating H2 O2 -induced SH-SY5Y cell injury and cell death.

TRPC1 protects dopaminergic SH-SY5Y cells from MPP+, salsolinol, and N-methyl-(R)-salsolinol-induced cytotoxicity

Neurotoxins and alterations in Ca2+ homeostasis have been associated with Parkinson's disease (PD), but the role of store-operated Ca2+ entry channels is not well understood. Previous studies have shown the neurotoxicity of salsolinol and 1-methyl-4-phenylpyridinium ion on SH-SY5Y cells and cytoprotection induced by transient receptor potential protein 1 (TRPC1). In the present study, N-methyl-(R)-salsolinol was tested for its cellular toxicity and effects on TRPC1 expression. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, DAPI (4',6-diamidino-2-phenylindole), fluorescein isothiocyanate-Annexin-V/propidium iodide, western blot analysis, and JC-1 labeling revealed that the three indicated drugs could induce caspase-dependent, mitochondrial-mediated apoptosis. Exposure of SH-SY5Y cells to the indicated drugs resulted in a significant decrease in thapsigargin-mediated Ca2+ influx and TRPC1 expression. Immunocytochemistry experiments revealed that neurotoxins treatment induced TRPC1 translocation to the cytoplasm. Taken together, our results indicate that treatment with neurotoxins may alter Ca2+ homeostasis and induce mitochondrial-mediated caspase-dependent cytotoxicity, an important characteristic of PD.

Protective effect of theaflavins on neuron against 6-hydroxydopamine-induced apoptosis in SH-SY5Y cells

Theaflavins, the oxidation products of tea polyphenols are important biologically active components of black tea. 6-hydroxydopamine is a pro-parkinsonian neurotoxin. Theaflavins could inhibit the auto-oxidation of 6-hydroxydopamine in a dose-dependent manner from 0.5 µg/ml to 25 µg/ml. Here we investigated the protective effect of theaflavins on 6-hydroxydopamine induced SH-SY5Y cells against apoptosis (within this concentration range). It was found that pretreating SH-SY5Y cells with 0.5 µg/ml of theaflavins prevented 6-hydroxydopamine-induced loss of cell viability, condensed nuclear morphology, attenuated 6-hydroxydopamine-induced apoptosis, decrease of mitochondrial membrane potential and the increase of intracellular nitric oxide levels. Our results indicated that theaflavins had protective effect against 6-hydroxydopamine induced apoptosis at low concentrations, possibly through inhibition of reactive oxygen species and nitric oxide production.